protection and strategic uses of groundwater...

PROTECTION AND STRATEGIC USES OF GROUNDWATER

RESOURCES IN DROUGHT PRONE AREAS

OF THE SADC REGION

GROUNDWATER SITUATION ANALYSIS OF THE

LIMPOPO RIVER BASIN

FINAL REPORT

This report is the final report on the project

Protection and Strategic Uses of Groundwater Resources in the Transboundary Limpopo

Basin and Drought Prone Areas of the SADC Region

Title of Consulting Services:

Groundwater Situation Analysis in the Limpopo River Basin

The project was funded through a grant from The Global Environmental Facility

(GEF Grant GEF-PDF TF027934 )

At the request of the World Bank a summary of the final report was prepared as a separate

document by the

Division of Water Environment and Forestry Technology

CSIR, Pretoria, South Africa

and issued as

Report No. ENV-P-C-2003-047

DIVISION OF WATER, ENVIRONMENT AND FORESTRY TECHNOLOGY CSIR

FINAL REPORT

PROTECTION AND STRATEGIC USES OF GROUNDWATER RESOURCES IN DROUGHT PRONE AREAS OF THE SADC REGION

GROUNDWATER SITUATION ANALYSIS OF THE LIMPOPO RIVER BASIN

Prepared for: Southern African Development Community (SADC)

Directorate for Infrastructure and Services Water Division Private Bag 0095 GABERONE Botswanao

Prepared by: Environmentek, CSIR

P.O. Box 395 0001 Pretoria South Africa Pretoria Project no: JQ390 October 2003 Report no: ENV-P-C 2003-026

Limpopo River Basin Groundwater Situation Analysis – Final Report

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CONTENTS 1. BACKGROUND TO AND PURPOSE OF THE STUDY.............................................. 1 2. OBJECTIVES AND SCOPE OF THE PROJECT........................................................ 3 3. SPECIFIC TERMS OF REFERENCE FOR THIS PHASE .......................................... 4 4. GROUNDWATER AND DROUGHT ............................................................................ 5 5. THE LIMPOPO BASIN AS STUDY AREA.................................................................. 6 5.1 Physiography ................................................................................................................ 6 5.2 Climate and Weather Patterns ..................................................................................... 7 5.2.1 Rainfall .......................................................................................................................... 9 5.2.2 Evaporation ................................................................................................................. 10 5.2.3 Aridity index................................................................................................................. 11 5.2.4 Temperature................................................................................................................ 12 5.2.5 Climate change and variability.................................................................................... 14 5.2.6 Drought........................................................................................................................ 14 5.2.7 Floods.......................................................................................................................... 17 5.2.8 Global warming ........................................................................................................... 18 5.3 Drainage Basins.......................................................................................................... 19 5.3.1 General description..................................................................................................... 19 5.3.2 Major tributaries of the Upper Limpopo River Reach................................................. 20 5.3.3 The Middle Reach....................................................................................................... 20 5.3.4 Lower Reach............................................................................................................... 21 5.4 Surface Water Resources and Hydrological Modelling of the Limpopo Basin .......... 21 6. WATER USE AND DEMAND IN THE LIMPOPO BASIN......................................... 24 6.1 Botswana..................................................................................................................... 24 6.2 Mozambique................................................................................................................ 26 6.3 South Africa................................................................................................................. 26 6.4 Zimbabwe.................................................................................................................... 27 7. GEOLOGY.................................................................................................................. 28 7.1 Major Geotectonic Divisions ....................................................................................... 28 7.2 Western Archaean-Mesozoic Complexes and Kalahari Basin .................................. 29 7.2.1 Archaean-Early Proterozoic basement....................................................................... 30 7.2.2. Late Archaean-Proterozoic sedimentary basins and layered intrusives.................... 30 7.2.3 Palaeozoic-Mesozoic Karoo basins............................................................................ 34 7.2.4 Cenozoic Kalahari basin ............................................................................................. 34 7.2.5 Mozambique (Coastal Basin)...................................................................................... 35 8 HYDROGEOLOGY..................................................................................................... 37 8.1 Hydrogeological Regions ............................................................................................ 37 8.2 Brief description of the hydrogeology of the four countries........................................ 38 8.2.1 Botswana..................................................................................................................... 38


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8.2.2. Mozambique................................................................................................................ 38 8.2.3 South Africa................................................................................................................. 39 8.2.4 Zimbabwe.................................................................................................................... 40 8.3 Hydrogeological region classification of the Limpopo Basin...................................... 41 8.3.1 Unit L0: Alluvium associated with river courses........................................................ 41 8.3.2 Unit L1: Fractured Basement Complex granites ........................................................ 44 8.3.3 Unit L2: Fractured Transvaal sequence and Bushveld complex .............................. 44 8.3.4 Unit L3: Fractured Waterberg, Palapye, Soutpansberg groups ................................. 45 8.3.5 Unit L4: Central Zone of the Limpopo Mobile Belt ..................................................... 45 8.3.6 Unit L5: Zimbabwean craton...................................................................................... 45 8.3.7 Unit L6: Kaapvaal craton ........................................................................................... 45 8.3.8 Unit L7: Unconsolidated sand and coastal plain aquifers ......................................... 45 8.4 Groundwater Potential and Resources ...................................................................... 45 8.4.1 Botswana..................................................................................................................... 45 8.4.2 Mozambique................................................................................................................ 46 8.4.3 South Africa................................................................................................................. 48 8.4.4 Zimbabwe.................................................................................................................... 48 8.4.5 Groundwater quality .................................................................................................... 51 8.5 Groundwater Recharge .............................................................................................. 52 8.5.1 Base flow estimation................................................................................................... 52 8.5.2 Chloride method for recharge determination.............................................................. 54 8.6 Groundwater Levels .................................................................................................... 55 8.7 Groundwater Monitoring ............................................................................................. 56 9. SHARED WATER RESOURCES.............................................................................. 58 9.1 Introduction ................................................................................................................. 58 9.2 Limpopo Alluvial Aquifers ........................................................................................... 59 9.3 River Flow ................................................................................................................... 59 9.4 Karoo Aquifers ............................................................................................................ 59 9.5 Pollution....................................................................................................................... 59 9.6 Coordinated Planning and Management.................................................................... 60 10. GROUNDWATER RELATED ENVIRONMENTAL ISSUES..................................... 61 10.1 Introduction ................................................................................................................. 61 10.2 Groundwater Dependent Ecosystems (GDEs) .......................................................... 61 10.2.1 Introduction to GDEs ............................................................................................... 61 10.2.2 GDEs and their importance in drought preparedness ............................................ 62 10.3 Aquatic Ecosystem Dependence................................................................................ 64 10.3.1 Summary ................................................................................................................. 64 10.3.2 Springs..................................................................................................................... 64 10.3.3 Wetlands.................................................................................................................. 64 10.3.4 Aquatic ecoregions .................................................................................................. 66 10.3.5 Fish and aquatic fauna ............................................................................................ 67 10.3.6 Endangered and vulnerable species....................................................................... 68 10.3.7 Aquifer and cave ecosystems................................................................................. 68 10.4 Terrestrial Ecosystems ............................................................................................... 68 10.4.1 Summary ................................................................................................................. 68


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10.4.2 Available information ............................................................................................... 69 10.4.3. Vegetation indicators of groundwater use .............................................................. 70 10.4.4 Vegetation types...................................................................................................... 70 10.4.5 Riparian areas ......................................................................................................... 73 10.4.6 Degree of impact..................................................................................................... 74 10.4.7 Conservation areas ................................................................................................. 76 10.5 Recommendations for GDE Site Selection ................................................................ 77 10.6 Recommendations for Future Work............................................................................ 77 11. GROUNDWATER MANAGEMENT ASPECTS......................................................... 81 11.1 Institutional Structures in the Different Limpopo River Basin Countries .................... 81 11.2 Regional Context ........................................................................................................ 81 11.3 Botswana..................................................................................................................... 84 11.4 South Africa................................................................................................................. 84 11.4.1 Legal framework...................................................................................................... 84 11.4.2 Institutional arrangements ....................................................................................... 85 11.4.3 Standards and guidelines ........................................................................................ 86 11.5 Zimbabwe.................................................................................................................... 86 11.6 Moçambique................................................................................................................ 87 11.6.1 Legal framework...................................................................................................... 87 11.6.2 Established standards and procedures for groundwater development.................. 88 11.6.3 Institutional framework ............................................................................................ 88 12. PILOT STUDY AREA(S) ............................................................................................ 90 12.1 Purpose of Pilot Study Area(s) ................................................................................... 90 12.2. Selection Criteria......................................................................................................... 90 12.3 Ecological Criteria ....................................................................................................... 91 12.4 Potential Pilot Study Areas and Motivations .............................................................. 92 12.5 Selection of Pilot Sites ................................................................................................ 94 12.6 Final Selection of Pilot Study Areas ........................................................................... 94 13. DESCRIPTION OF THE TWO SELECTED PILOT STUDY AREAS ........................ 98 13.1 Western Pilot Study Area............................................................................................ 98 13.1.1 Physiography, drainage and climate....................................................................... 98 13.1.2 Land cover and land-use......................................................................................... 99 13.1.3 Population distribution ........................................................................................... 101 13.1.4 Geological description ........................................................................................... 101 13.1.5 Geohydrological considerations ............................................................................ 102 13.2 Eastern Pilot Study Area........................................................................................... 104 13.2.1 Physiography, drainage and climate..................................................................... 104 13.2.2 Land cover and land-use....................................................................................... 106 13.2.3 Population distribution ........................................................................................... 106 13.2.4 Geological description ........................................................................................... 107 13.2.5 Geohydrological considerations ............................................................................ 109 13.3 Conservation Areas .................................................................................................. 109 13.4 Groundwater-Dependent Ecosystems in the Pilot Areas ......................................... 110 13.4.1 Introduction ............................................................................................................ 110


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13.4.2 Floodplain groundwater dependent ecosystems.................................................. 112 13.4.3 Preliminary Mapping of Groundwater Dependent Ecosystems............................ 114 13.4.4 Conclusions ........................................................................................................... 117 14. GROUNDWATER VALUATION IN THE LIMPOPO BASIN: A PRELIMINARY SCOPING OF THE ISSUES.......................................................... 118 15. FIELD VISITS TO AND DISCUSSIONS RELATED TO THE TWO PILOT STUDY AREAS............................................................................................. 121 15.1 Introduction ............................................................................................................... 121 15.2 Socio-economic aspects ........................................................................................... 121 15.3 Country Reports ........................................................................................................ 122 15.3.1 Botswana............................................................................................................... 122 15.3.2 South Africa ........................................................................................................... 126 15.3.3 Moçambique .......................................................................................................... 132 15.3.4 Zimbabwe.............................................................................................................. 134 15.4 Conclusions............................................................................................................... 137 16. PROJECT COMPONENTS...................................................................................... 139 17. REFERENCES.......................................................................................................... 148 APPENDIX A: TERMS OF REFERENCE............................................................................ 160 APPENDIX B: SUPPLEMENT TO SECTION 10: GROUNDWATER RELATED ENVIRONMENTAL ISSUES. DESCRIPTIONS OF ECOREGIONS FOUND IN THE LIMPOPO BASIN ........................................... 165 APPENDIX C: SUPPLEMENT TO SECTION 15: SOCIO-ECONOMIC ASPECTS OF THE TWO PILOT STUDY AREAS ............................................................... 170

LIST OF FIGURES Figure 1.1: The Limpopo catchment showing the main tributaries of the Limpopo River in the different countries.................................................................................2 Figure 4.1: Schematic representation of the role of groundwater to bridge meteorological droughts . ........................................................................................5 Figure 5.1: Percentage of total area of the Limpopo basin within each of the four riparian countries .....................................................................................................6 Figure 5.2: Digital elevation model (DEM) of the Limpopo Basin ............................................7 Figure 5.3: Landscapes of the Limpopo Basin .........................................................................8 Figure 5.4: The Limpopo Basin showing the distribution of mean annual rainfall, the major tributaries and the international borders. ................................................9


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Figure 5.5: Mean rainfall in the Limpopo Basin from two different sources, covariance of the rainfall (GHCR data) and examples of the rainfall ...................... during recent particularly dry and wet years.........................................................10 Figure 5.6: The Limpopo Basin showing the distribution of potential evapotranspiration, the major tributaries and the international borders ..............................................11 Figure 5.7: Distribution of the Aridity Index (MAP/PET) across the Limpopo Basin...............12 Figure 5.8: Mean daily temperatures in winter (top) and summer (bottom) in the Limpopo Basin. ................................................................................................13 Figure 5.9: The relationship between annual recharge and annual rainfall in Southern Africa . ....................................................................................................16 Figure 5.10: Zimbabwean National rainfall deviation from the mean for the period 1910 to 2000 . .......................................................................................................17 Figure 5.11: Mean monthly flow at Chokwe over the period 1971 to 1995 in x 106 m3/a. .....23 Figure 7.1: Simplified geological map of the Limpopo basin showing the major geological units and the broad divisions between the Archaean-Mid- Mesozoic of Botswana, South Africa and Zimbabwe and Mozambique Coastal Basin . ........29 Figure 7.2: Major stratigraphic subdivisions in the Limpopo Basin........................................32 Figure 7.3: Schematic W-E Geological cross section ............................................................33 Figure 8.1: Simplified geological map of the Limpopo Basin .................................................42 Figure 8.2: Hydrolithological units within the Limpopo Basin.................................................42 Figure 8.3: Borehole density map for Botswana, Mozambique and South Africa. ................50 Figure 8.4: Groundwater quality expressed as EC (mS/m) across the Limpopo basin.........51 Figure 8.5: Groundwater quality expressed as TDS (mg/l) across the Limpopo Basin ........52 Figure 8.6: Nitrate concentrations in groundwater of South Africa and Botswana................53 Figure 8.7: Estimated base flow at gauge A7H003 (Herold method) ....................................54 Figure 8.8: Groundwater recharge in mm/a and as a percentage of MAP for each of the main hydrogeological regions ...........................................................54 Figure 8.9: Groundwater levels (metres below ground level) ................................................55 Figure 8.10: Map showing the distribution of groundwater monitoring stations in the Limpopo Province of South Africa........................................................................57 Figure 10.1: Occurrence of Springs and Wetlands from available datasets..........................65 Figure 10.2: Aquatic ecoregions of southern Africa ...............................................................67 Figure 10.3: Average root depths for different vegetation types ............................................69 Figure 10.4: The distribution of White’s (1983) vegetation types based on plant species and plant community distribution patterns............................................71 Figure 10.5: Distribution of the vegetation ecoregions within the Limpopo Basin. ................71 Figure 10.6: Ephemeral riparian GDE. A cross-section of an ephemeral river system showing the layering of the alluvial sediments, perched storage off groundwater and deep rooting of the woody plants. ........................73 Figure 10.7: Conservation areas within the basin. .................................................................77 Figure11.1: The vicious circle of water resource management in Africa. ..............................83 Figure 12.1: Proposed pilot study sites. For an explanation of the numbers, refer to text...95 Figure 12.2: The position of the two selected Pilot Study Areas along the Limpopo River...97 Figure 13.1: Physiography of the Western Pilot Study Area showing the major


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rivers and towns...................................................................................................98 Figure 13.2: Distribution of mean annual rainfall (MAP) for the Western Pilot Study Area...99 Figure 13.3: A land cover classification of the Western Pilot Study Area............................100 Figure 13.4: Population distribution for the Western Pilot Study Area.................................101 Figure 13.5: Geological map for the Western Pilot Study Area. ..........................................102 Figure 13.6: Groundwater levels shown as depth below surface in the Western Pilot Study Area. Only borehole data were available for Botswana and South Africa. ..............................................................................................103 Figure 13.7: Physiographic map of the eastern pilot area showing the international boundaries, major rivers and towns. ............................................105 Figure 13.8: Distribution of mean annual rainfall in the eastern pilot area. .........................105 Figure 13.9: A land cover classification of the eastern pilot area. Data from the classification being developed for the SADC by the CSIR...............................106 Figure 13.10: Population distribution for the Eastern Pilot Study Area................................107 Figure 13.11: Geological map for the Eastern Pilot Study Area. .........................................108 Figure 13.12: Groundwater levels shown as depth below surface in the Eastern Pilot Area ........................................................................................................109 Figure 13.13: Existing conservation areas in the western pilot area. ..................................110 Figure 13.14: Existing conservation areas in the eastern pilot area ....................................111 Figure 13.15: Cross section of a typical alluvial river bed showing the main features and relationships with different flow and flood levels. .....................112 Figure 13.16: A cross section of the Limpopo floodplain showing the different vegetation types and species associations....................................................114 Figure 13.17: A false colour satellite image of the WPA showing vigorous vegetation as orange to red shades with bare areas in white and low vegetation cover or dead vegetation in blue shades........................115 Figure 13.18: A false colour satellite image of the EPA showing vigorous vegetation as orange to red shades with bare areas in white and low vegetation cover or dead vegetation in blue shades........................116 Figure 13.19: A processed satellite image of the WPA showing the normalized difference vegetation index (NDVI) which shows vigorous vegetation as red shades with bare areas and low vegetation cover or dead vegetation in paler shades. ............................................................................116 Figure 15.1: Water meter at yard connection in the Masisi area showing the special meter reference numbering system designed for the area. .................128

LIST OF TABLES Table 1.1: Surface areas in each country of the Limpopo Basin .............................................1 Table 5.1: Classification of climatic aridity using the Aridity Index ........................................11 Table 5.2: Recorded droughts in South and southern Africa.................................................15 Table 5.3: High rainfall periods and floods in southern Africa................................................18


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Table 5.4: Major tributaries to the Limpopo River in the Upper, Middle and Lower Reaches of the Limpopo River and the countries where they join the Limpopo. ..........................................................................................................19 Table 5.5: Flow balance details of the Limpopo Main Stem for the period 1971-1995 .........22 Table 5.6: Estimated water resources of the Limpopo Basin as per local major catchment or country.............................................................................................23 Table 6.1: Demand Forecasts for the Botswana section of the Limpopo Basin. ...................25 Table 6.2: Statistics on annual water requirements within the Limpopo Basin of South Africa for the year 2000 (x 106 m3)..............................................................26 Table 6.3: Statistics on the current annual ground water use the Limpopo Basin of South Africa ...........................................................................................................26 Table 6.4: Major irrigation areas using groundwater resources in the Limpopo Basin .........27 Table 7.1: Stratigraphic column for the Limpopo Basin geology............................................31 Table 7.2: Mesozoic-Cenozoic geologic time scale and stratigraphic units of southern Mozambique ............................................................................................35 Table 8.1: Representation of Geohydrological Regions or Units in the Limpopo Basin........43 Table 8.2: Groundwater storage in alluvium associated with the Limpopo River and its main tributaries...................................................................................................44 Table 8.3: Groundwater resources and utilization in the Limpopo Basin, South Africa ........49 Table 8.4: Estimated Base Flow in the Quaternary catchments along the Limpopo River (inside SA boundary) .....................................................................53 Table 8.5: Groundwater Monitoring Network within the Limpopo Basin (Botswana) ............56 Table 10.1: Goods and services offered by ecosystems (Jansson et al, 1994). ...................63 Table 10.2: Ecologically important riparian wetlands recorded in the southern African portion of the Limpopo Basin. ..................................................................66 Table 10.3: Major wetlands in Zimbabwe and Mozambique ...................................................66 Table 10.4: Total number of species and threatened species (T) by country and taxonomic group. ..................................................................................................68 Table 10.5:. The area of the different vegetation types within the Limpopo Basin and all the SADC countries as mapped and described by White (1983) and the WWF (WWF 2001). ..................................................................................72 Table 10.6: Area of the Limpopo Basin which is conserved in some form of reserve by country and conservation status. Summarised from data supplied by the Peace Parks Foundation. ............................................................76 Table 11.1: Institutional water management levels in the different Limpopo River Basin countries...........................................................................................82 Table 12.1: Site evaluation matrix ..........................................................................................96 Table 14.1 Water use and costs ..........................................................................................119 Table 14.2: Population statistics in the piloy study areas....................................................119 Table 15.1: Water supply to villages in the Western Pilot Study area. ................................123 Table 15.2: Mapai Administration Post Data ........................................................................133 Table 15.3: Government developed irrigation schemes in southern Zimbabwe .................137 Table 16.1: Project components, subcomponents and activities. Water use and costs ....141


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CSIR Environmentek Report No: ENV -P-C-2003-026 1

1. BACKGROUND TO AND PURPOSE OF THE STUDY This project is part of a larger initiative identified by the SADC Water Sector Coordination Unit in their Regional Strategic Action Plan for Integrated Water Resource Development and Management (RSAP). A grant from the Global Environmental Facility (GEF) to the World Bank as implementing agent has been secured for this project. Within the framework of the above-mentioned SADC Regional Strategic Action Plan, a project referred to as “Protection and Strategic Use of Groundwater Resources in the Transboundary Limpopo Basin and Drought Prone Areas of the SADC Region”, was implemented. This project forms part of a larger initiative referred to as “Protection and strategic use of groundwater resources in drought prone areas of the SADC region”. Two projects will be completed during the first phase of the larger project, namely, (1) a groundwater situation analysis of the Limpopo Basin, and (2) a regional groundwater situational analysis of the SADC region. The study area for this project and the major drainage lines contributing to the Limpopo River is shown in Figure 1.1. The four countries share the basin: Botswana, Mozambique, South Africa and Zimbabwe. Total catchment area included in the study approximately 408 000 km2. The approximate catchment sizes in the four countries is shown in Table 1.1

Table 1.1: Surface areas in each country of the Limpopo Basin

Country Surface area (km2) Percentage of Limpopo Basin Surface Area

Botswana 81 400 19.9 Mozambique 79 800 19.6 South Africa 184 150 45.1 Zimbabwe 62 900 15.4 Total 408 250 100

The current project should integrate closely with the results of previous and current hydrogeological, social, economical, and natural resource investigations carried in the four countries sharing water and other natural resources from within the Limpopo Basin. This would include for example the results of specific and regional investigations, hydrogeological mapping, development plans (water, infrastructure, economic, etc), social development, ecological and economic sustainability studies, etc. This project will consist of two main components: • Implementation of a groundwater situation analysis for the Limpopo River basin, and • Selection of a pilot area within the basin for implementing the GEF project on protection

and strategic uses of ground water resources in drought prone areas of the SADC region.



Figure 1.1: The Limpopo catchment showing the main tributaries of the Limpopo River in the different countries.

.. , ".,

, • i.\l- !li!

J South Africa .. ,

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1I I 1

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...,b.ND Cl Intemationll Boundllry

I N Rl¥er Cl Uimpopo B.-In



2. OBJECTIVES AND SCOPE OF THE PROJECT The Southern African Development Community (SADC) is aware of the critical role groundwater plays in the region, especially with regard to rural water supply and to a lesser extend for urban water supply. As the region is characterised by a rapid population growth, pressure on groundwater resources is constantly increasing. This pressure is illustrated by the extended drought periods followed by occasional extreme flood-events that are experienced in the region. SADC therefore recognises the key role of groundwater for the alleviation of drought in the region they serve. However, policy responses to drought have in the past been based on short-term crisis actions, which have generally proved to be inefficient or ineffective. To address this undesirable situation SADC supports the implementation of proactive, sustainable and integrated management of groundwater resources, taking into careful consideration the ecosystem needs. The overall objective of this project is for the SADC Member States to develop cooperatively a strategic regional approach to support and enhance the capacity of its Member States in the definition of drought management policies, specifically in relation to the role, availability (magnitude and recharge) and supply potential of groundwater resources. The intention is to carry out a rapid, but comprehensive and critical overview of existing situation and issues related to groundwater and drought mitigation, and to propose structured project options and cost estimates for discussion. Reconciliation of the demands for socio-economic development, particularly for rural communities, and those of the principal groundwater-dependent ecosystems will be assisted by the outcome of this project. The current project will be developed at two levels: the regional level and the river-basin level. In the Limpopo project we are concerned with the river basin level where the role of groundwater in proactive drought mitigation will be demonstrated in the semi-arid Limpopo river basin on a conceptual level and at the field-scale in a pilot sub-catchment. The outcome of the two projects (Regional and Limpopo River Basin scale) will provide input to a proposal for a much larger and more detailed GEF funded project addressing the entire SADC region. Key issues to be addressed during the project will include

• Review aspects related to groundwater resources and uses in the Limpopo Basin • Geology and aquifer types and condition • Recharge • Role of rivers • Study of climatic conditions and the occurrence of drought and flood conditions • Internationally shared aquifers • Ground water use and management in the area • Review of current conditions and potential threats to ground water resources • Identification of ground water user groups and key role players in the water sector

of the region • Ground water dependent ecosystems (GDE) • Social and economic sustainability within the region • Selection of a pilot area(s) within the Limpopo Basin • Stakeholder workshop in a selected pilot area(s).



3. SPECIFIC TERMS OF REFERENCE FOR THIS PHASE Critical aspects from the terms of reference of the consultancy is to prepare an overview of the groundwater conditions of those sections of the each of the four countries Botswana, Mozambique, South Africa and Zimbabwe contributing to the Limpopo basin. This information will then to be used to select a one of more potential pilot study sites where follow up work will be done concentrating on more detailed geohydrological aspects, and most importantly, address the social aspect of developing, utilizing and managing ground water resources as part of an IWRM approach by involving a wide selection of stakeholders during this phase. This will be followed by more in-depth studies in the pilot study area(s) (Phase II). Following the submission of the Inception report, SADC has requested that more emphasis should be given to environmental aspects such as groundwater dependent ecosystems, than was requested in the original Terms of Reference. These aspects have been addressed at length in this report, both for the entire basin, as well as for the Pilot Study areas. For ease of reference, the full terms of reference as issued by SADC, are included as Appendix A.



4. GROUNDWATER AND DROUGHT Meteorological droughts have become almost synonymous with Africa, not only in the low rainfall and runoff regions, but also in those areas with traditionally much higher rainfall. Many consider drought to be the most complex but least understood of all natural hazards, and partly due to its usually long duration, affecting more people than any other hazard. The concept of integrated drought management, in which groundwater has an important role to play, is promoted worldwide and has particular relevance in Sub-Saharan Africa. Coupled to this, is the impact of drought on groundwater recharge, and its link to the international concern about the long-term sustainability of groundwater resources. Reeve and Watts (1994) have stated that drought in the African continent could result in the greatest environmental and human disaster ever to occur. One of the key advantages of groundwater is its reliability during periods of surface water drought. However, the buffering capacity groundwater has during periods of drought is not without limits and needs to be managed properly. Poor management of groundwater resources during periods of source water drought can again lead to a condition of “groundwater drought” (BGS, 2002). Proper management of groundwater resources in turn, can only be achieved if all aspects of the resource are well understood. In the past the response to drought has been mainly reactive. UNESCO advocates the development and implementation of integrated drought management policies by integration across various sec tors impacted upon by drought. An important aspect here is the sustainable management of natural resources such as water. Groundwater systems have much longer reaction times compared to that of surface water systems. This phenomenon forms the key to the use of groundwater during periods of drought as it allows a bridging period when surface water deficits occur and is illustrated in Figure 4.1.

Figure 4.1: Schematic representation of the role of groundwater to bridge meteorological droughts (Ref: www.bgs.ac.uk/hydrogeology).

The development of groundwater management strategies for drought prone areas is a key priority in terms of the overall water management in the SADC region. Many areas in Africa south of the Sahara can be classified as drought prone, and therefore a better understanding of the groundwater situation of the region will assist greatly to reduce the impact of drought in the region. This project forms part of this long-term programme to address some of the aspects related to drought through the development of a better understanding of the groundwater resources of the region and how these resources can be used effectively to minimize the impact of drought.



5. THE LIMPOPO BASIN AS STUDY AREA The Limpopo Catchment covers an area of about 408 000 km2 and is shared by the four southern African countries, Botswana, Mozambique, South Africa and Zimbabwe (Figure 1.1). The largest section of the catchment is within South Africa, followed by Mozambique, Botswana and Zimbabwe. The area distribution as a percentage in the four countries is shown in Figure 5.1. The Limpopo basin is located between latitudes 22° and 26° South and longitudes 26° and 35° East. A rough outline of the catchment boundaries is given by the towns Xai-Xai, Chigubu (Mozambique), Rutenga, Bulawayo, Plumtree (Zimbabwe), Lobatse, Serowe, Thakadu (Botswana), Johannesburg, Middelburg, Phalaborwa (South Africa), Xai-Xai.

Botswana20%

Zimbabwe15%

Mozamb.20%

S Africa45%

Figure 5.1: Percentage of total area of the Limpopo basin within each of the four riparian countries. Economic activity within the South African part of the basin varies significantly across the basin and includes: livestock farming, irrigation, mining, industrial operations, forestry, tourism and eco-tourism, and game farming. In Zimbabwe the economic activity is centred mainly around livestock farming, irrigation and mining. Apart from the diamond mining activities of Botswana, the second most important area of economic activity in the country is located along the eastern border of the country, a large portion of which is within the Limpopo basin. Here the main economic activities are mining, light industries, livestock farming, and tourism. In Mozambique the economic activity in the interior of the Limpopo basin is based on informal and subsistence farming, agriculture based on large-scale irrigation from the Limpopo and, closer to the coast, fishing and tourism are the main areas of economic activity. 5.1 Physiography The Limpopo and its tributaries drain fairly flat countryside except in South Africa (Figure 5.2). In Botswana the watershed between the Limpopo basin and the central Kalahari is at an elevation of between 1 500 mamsl (south of Lobatse) and 1200 mamsl (near Thakadu), with the countryside gently sloping towards the river. At the confluence with the Shashe River the Limpopo River is at an elevation of nearly 1 000 mamsl. The northwestern watershed in Zimbabwe near Bulawayo is also close to 1 500 m with low relief between the watershed and the Limpopo. At Pafuri, where the river enters Mozambique and where the Levuvhu River joins the Limpopo, the elevation is close to 200 mamsl. In Mozambique the Limpopo River traverses the southern portion of an extensive broad coastal plain that extends for several hundred kilometres to the north along the coast.



Topographically the South African portion of the catchment is totally different with several extensive mountainous regions. The most pronounced of these are the Waterberg range north and northwest of Nylstroom, the Strydpoort Mountains south of Pietersburg, the Soutpansberg around Louis Trichardt, and the Mpumalanga Drakensberg along the eastern edge of the catchment. Elevations of more than 2 000 mamsl occur in these regions. Extensive plains are found in between these mountain ranges, for example the Springbok Flats, the Eastern Transvaal coalfields centred around Witbank, and the plains bordering onto the Limpopo River. It is interesting to note that the southern watershed in South Africa (around Johannesburg and further to the east) is also at an elevation of around 1 500 mamsl. Most of the landscapes are classified as flat or undulating plains ranging from low-lying on the Mozambique plains through the middle altitudes over most of the basin to high altitudes in the montane areas (Figure 5.3). Undulating plateaux are found on the South African highveld and the adjacent transitional areas. The gentle relief results in relatively slow flowing and meandering rivers which accumulate extensive alluvial deposits on their floodplains, particularly upstream of points where relatively hard rock such as dykes, or vertical displacement of the underlying bedrock by faults, forms natural dams (Palmer et al. 2002). Many of the grassland and bushveld wetlands are found in the flat plain and plateau areas. Escarpment areas with significant relief are found along the Drakensberg escarpment, northwards to the Soutpansberg and the Waterberg in the southwestern part of the catchment. The remaining area of the catchment is composed largely of rolling hills. All these areas tend to have relatively rapidly flowing streams and rivers which do not accumulate alluvial deposits.

Figure 5.2: Digital elevation model (DEM) of the Limpopo Basin

5.2 Climate and Weather Patterns The climate in the different parts of the basin is controlled primarily by three factors: the position of the basin relative to the Inter Tropical Convergence Zone (ITCZ) and the associated high pressure systems; the distance from the Indian Ocean which is the chief



source of moisture; and the altitude above sea-level. The three main climate systems are the (Ashton et al., 2001):

• Sub-tropical eastern continental moist maritime system and its periodic cyclones which bring high winds and heavy rainfall (e.g. Domoina in 1984);

• South Indian Ocean high pressure system which produces south-easterly winds that convey moist oceanic air over the land, bringing rains; and

• ITCZ which is situated over the tropics but, sometimes, moves sufficiently far southwards to bring heavy rains to the northern parts of the basin.

Figure 5.3: Landscapes of the Limpopo Basin

All these systems are strongly influenced by the El Nino phenomenon. When this is strong, it leads to drought conditions over southern and south-eastern Africa, and when weak brings periods of above average rainfall (Tyson and Gatebe 2001). Over South Africa the El Nino effect is modulated by the upper atmosphere Quasi Biennial Oscillation which can reduce or enhance its impact relative to the countries to the north as appears to be happening in the current drought. The climate in the Limpopo Basin varies over a wide range, from sub-tropical to semi-desert to montane. The climate of the Mozambique coastal belt is sub-tropical and sub-humid but the dominant climate over most of the central and upper river valley is subtropical and semi-arid (Schulze and McGee 1978). Much of the interior is warm temperate becoming cool temperate in the higher mountain areas of South Africa. The western end of the basin in Botswana and the South Africa has a dry, hot steppe semi-arid climate. Over most of the basin the average annual water surplus is very low, as is reflected in the low mean surface runoff of about 13 mm. The runoff only exceeds 100 mm on the Drakensberg escarpment in the Olifants River basin (Carter 1954 in Schulze and McGee 1978). The annual moisture deficit is greater than 400 mm over most of the basin, more than 800 mm over most of the Limpopo valley down river from the confluence with the Motlouse to the confluence with the Olifants, and reaches more than 1 000 mm in the upper Changane catchment.



5.2.1 Rainfall The rainfall occurs in summer over the entire basin with the wettest months being from November to March and the driest being from May to October (Knoch and Schulze, 1957 in Schulze and McGee, 1978). The lowest rainfall occurs over the central Limpopo basin, increasing northwards into Zimbabwe and southwards into South Africa (Ashton et al. 2001; Figure 5.4). The highest rainfall of more than 800 mm is found in the upper Olifants River catchment and in its sub-catchments along the Drakensberg escarpment. The mean annual rainfall varies from 250 mm in the hot dry central Limpopo valley and Mozambique interior to more than 1 000 mm in the montane areas in South Africa, reaching 1 500 mm on the crests of the mountain areas in South Africa (too limited to show in the figure). Most of the basin gets less than 500 mm per year. The rainy season is generally short, marked by intense rainstorms and dry periods between the storms, particularly in the drier areas. The long intervals between successive storms increase the risk of dryland crop failures or significant reductions in yields (SARDC/IMERCSA/ZERO 2002).

Figure 5.4: The Limpopo Basin showing the distribution of mean annual rainfall, the major tributaries

and the international borders (FAO 2001). There are differences in the mean rainfall distributions between data sets from different sources as shown in Figure 5.5. These are presumably mainly due to the different periods over which the mean values were calculated, the FAO data being specifically chosen to represent conditions prior to the onset of marked trends in the African climate which could indicate global change. The coefficient of variation (CV) of the rainfall, based on the GHCN data shows interesting patterns. The general rule is that the variability of the rainfall increases with increasing aridity so that the median rainfall becomes more representative of the expected rainfall than the mean (Schulze et al. 1997). This pattern is evident in the basin but the there are relatively low CV values in the very dry area roughly centred on the Shashe-Limpopo confluence - Beit Bridge region compared with the areas to the east and



west. There is also a high CV in southern Mozambique, probably because of the very high rainfalls associated with cyclones in this relatively low rainfall area. The high CV has important implications for groundwater recharge. The dry year of 1994 and the wet year of 2000 clearly illustrate some of these extremes, with even the higher lying, and important surface runoff yielding, areas of South Africa being very dry during 1994.

Figure 5.5: Mean rainfall in the Limpopo Basin from two different sources, covariance of the rainfall (GHCR data) and examples of the rainfall during recent particularly dry and wet years.

5.2.2 Evaporation The potential evaporation is high throughout the basin including the Mozambique coastal belt (Figure 5.6). The values in this figure are lower than those given in the text below because they are based on modelled evaporation using the FAO Penman-Monteith methodology while the figures in the text are based on measurements from evaporation pans at meteorological stations. The FAO method is believed to give a better estimate of potential evaporation from healthy vegetation but is based on relatively few sites (which have full weather measurements) compared with the number of pan measurement sites. The general distribution is very similar so both values are given here for completeness. The values in the map have also been generalised and the potential evaporation in the higher lying areas of the Drakensberg Escarpment and Soutpansberg will be lower than is shown here. Potential evaporation is high throughout the basin including the Mozambique coastal belt. Evaporation is highest in the Limpopo valley upstream of the confluence with the Shashe River, with measuring pan (open water) evaporation ranging from 1 950 mm in the southwest to 1 770 mm in the eastern part (Boroto and Görgens 1999; Schulze et al. 2001). Between the Shashe River confluence and Beit Bridge pan evaporation reaches up to 1 855 mm in the Limpopo valley dropping to about 1 520 mm in the upper reaches of the Shashe and



Umzingwane River catchments. In the reach between Beit Bridge and Pafuri evaporation ranges from 2 000 mm in the Limpopo valley to 1 600 mm in the upper reaches of the tributaries. Evaporation is high in the stretch between Pafuri and Chokwe, reaching 1 700 mm in the Limpopo valley, but decreases towards the higher lying parts of the catchment to about 1 550 mm and also towards the coast at Xai-Xai.

Figure 5.6: The Limpopo Basin showing the distribution of potential evapotranspiration, the major tributaries and the international borders (FAO 2001)

5.2.3 Aridity index The aridity index is calculated as the ratio of mean annual precipitation (MAP) to mean potential evaporation (PET) and is used as an index in classifying the aridity of climates. It is a measure which indicates the amount of energy which is available to evaporate water, relative to the amount of water received by that environment from precipitation. The Aridity Index is generally divided into a number of classes, primarily to indicate susceptibility to desertification i.e. the degradation of the vegetation with concomitant loss of the productivity required to sustain livelihoods and biodiversity (UNCCD 1994; Table 5.1). Desertification susceptibility is high in semi-arid and arid areas with hyper-arid areas being considered too extreme to support dense populations and thus very vulnerable to further desertification. Most of the Limpopo Basin falls within the arid and semi-arid classes (Figure 5.7), indicating the considerable potential for inappropriate resource and land-use practices to lead to desertification.

Table 5.1: Classification of climatic aridity using the Aridity Index (UNEP 1992). Climate Zone Ratio of Mean Annual Precipitation to Potential Evapotranspiration

Hyper-arid <0.05

Arid 0.05-0.20

Semi-arid 0.21-0.50

Dry sub-humid 0.51-0.65

Humid > 0.65



Figure 5.7: Distribution of the Aridity Index (MAP/PET) across the Limpopo Basin. For more information see the text. The values in the figure were calculated using the FAO Penman-

Monteith method and will be more conservative than those estimated using evaporation pans. 5.2.4 Temperature Air temperatures across the basin show a marked seasonal cycle, with highest temperatures recorded during the early Austral Summer months and lowest temperatures during the cool, dry winter months. In summer, the daily temperatures may soar above 40°C, while in winter temperatures may fall to zero. The general temperature figures are closely related to altitude and to the distance from the ocean. The same trends are evident in the daily mean temperatures for summer and winter (Figure 5.8). The mean maximum temperature in most of the Limpopo basin (notably South Africa, Botswana and Zimbabwe) varies from 30 to 34°C during summer to 22 to 26°C in winter. The eastern and northern parts of the Limpopo basin are frost-free while the southern and western areas experience winter frost. The January mean daily maximum temperatures in most of the Limpopo valley itself are between 32 and 34°C with the extreme maximums being more than 40°C (ACU 1961; Schulze et al. 1997). In the higher lying areas of southern Zimbabwe and South Africa, the January mean maximums are between 27 and 29°C. On the coastal plain in Mozambique the corresponding temperatures are about 30°C. January mean minimum temperatures range from 18 to 19°C in the lower-lying interior to 20 to 22°C on the coastal plain and 13 to 15°C on the highveld in South Africa. In July mean daily maximum temperatures range from 22 to 24°C in the interior to 26°C on the coastal plain. In southern Zimbabwe they range from 20 to 24°C and 18 to 20°C in the higher mountain areas (e.g. Soutpansberg) and highveld of South Africa. The mean daily minimum temperatures along the central and lower Limpopo valley itself range from 10°C in the interior to 12 to 14°C at the coast. In the upper Limpopo and on the highveld they decrease to 1 to 3°C, and –2 to 2°C in the upper Notwane and Marico catchments. The corresponding temperatures in southern Zimbabwe are 4-7°C. Daily temperature ranges in the interior can be in excess of 30°C, occasionally 35-40°C in the far west of the catchment, but are strongly moderated by the oceanic influence in the coastal areas to 4-5°C.



Figure 5.8: Mean daily temperatures in winter (top) and summer (bottom) in the Limpopo Basin. These differences in winter (July) minimum temperatures are in line with general absence of frost in the lower Limpopo River valley and the northern and eastern parts of the catchment



(SARDC/IMERCSA/ZERO 2002). The mean number of frost days in South Africa ranges from one in the central and upper Limpopo valley to 20 to 30 days in the montane and highveld areas (Schulze et al. 1997). 5.2.5 Climate change and variability The most recent overview of climatic change in eastern and southern Africa was published in 2001. Tyson and Gatebe (2001) cover the atmospheric changes and Schulze et al. (2001) review the hydrological implications. Although the general effects of global climate change and variability have been predicted for the regions, they must still be formally confirmed for both southern Africa, and the Limpopo River Basin. Two recent trends are, however, apparent:

• The last 20 years have been the warmest on record; • Drought and flood occurrences are becoming more frequent; • Atmospheric pollution levels, although steadily worsening, remain close to negligible

when considered in the global sense (SADC/IUCN/ZRA/SARDC 2000) so that local pollutants are having only a limited impact.

5.2.6 Drought From a climatic perspective, large areas in southern African are regarded as semi-arid. Scientifically, droughts are usually classified as meteorological, agricultural or hydrological, depending on the variables under consideration. The variables that indicate the presence and severity of agricultural and hydrological drought derive from those associated with meteorological drought, or are directly influenced by them. When dealing with drought in Southern Africa, a combination of the variables rainfall, temperature, soil moisture, evapotranspiration, riverflow, status of reservoirs and underground water resources are usually the critical issues. If the popular definition of drought being a period of low rainfall is applied to describe the climatic conditions in many parts of southern Africa, for example the Limpopo Basin, periods of drought would be common. Meteorologists, for example define drought solely on the basis of the degree of dryness and the duration of the dry period, whereas hydrologists link periods of shortfall to the effect on surface and subsurface water resources. Agriculturalists again link drought to soil water deficits and impacts on crops. From the social scientists view, drought is seen as a relative phenomenon, which varies according to the demand placed on the resource by the different uses. Central to all definitions is the relative shortage of water (Calow et al, 2002). The term groundwater drought has been added to this list during the last decade or two. A groundwater drought occurs when groundwater sources fail as a direct consequence of drought. Water-related activities in a region should be in harmony with the amount of water which, under normal conditions, is available for those activities. “Normal” is often taken as to be the mean amount of water available, however, this notion of drought is rather inadequate. It is the occurrence of negative deviations from the required levels rather than from the mean which constitutes droughts. In other words, a drought occurs when there is less water available than is needed, and not when there is less than expected. Droughts are multi-facetted problems and require a developmental rather than a crisis management approach (UNESCO, undated) What is more important is that the region experiences periodic times of water shortages which constitute a serious threat to life and livelihood. Four terms have been developed to describe drought conditions, or the impact thereof, more clearly. These are water shortage,



water scarcity, water stress and water security. Abrams (1997) described these four terms as follows:

• Water shortage is used describe an absolute water shortage when the available water does not meet defined minimum requirements.

• Water scarcity focuses more on the relationship between demand for water and its availability and depends to a large degree on the sectoral use patterns within a region or country.

• Water stress is the symptomatic consequence of scarcity which may manifest itself as increasing conflict over sectoral use, crop failure, decline in service levels, etc, and

• Water security is a situation of reliable and secure access to water over time. Since the single most important variable that defines drought in southern Africa is rainfall (Zucchini and Adamson, 1984). In terms of groundwater resources, rainfall is critical to the replenishment of the resource. For this discussion drought periods will therefore be viewed in terms of the rainfall record and deviations from the long term mean values. The rainfall in the basin varies on both long and medium term cycles, with the basic cycle from wet to wet being about 18-20 years (Preston and Tyson 2000). This can be seen in the severe droughts extending back to the 1920s in the historical records (Table 5.2). An analysis of climatic records for high rainfall and floods in the Kalahari region suggest that there were major droughts (probably of regional extent) in 1831-35, 1844-51, 1857-65, 1877-86 and 1894-99 (Nash and Endfield 2002).

Table 5.2: Recorded droughts in South and southern Africa (Tyson, 1986; Preston and Tyson 2000; Ashton et al. 2001; SADC/IUCN/ZRA/SARDC 2000 in SARDC/IMERCSA/ZERO 2002)

Period Notes 1905/06-1915/16 1925/26-1932/33

Driest season 1913/14 Regional drought over north-eastern South Africa and probably the rest of the basin; <80% of mean rainfall

1944/45-1952/53 Dry over the whole of South Africa and probably the rest of the basin; <90% of mean rainfall

1962/63-1970/71 Dry over the entire sub-continent; <90% of mean rainfall 1982/83 Dry over the summer rainfall region and most of sub-tropical Africa; ±68%

of mean rainfall in northern South Africa 1986/87 Dryer conditions over the region 1991/92 Southern Africa, excluding Namibia experience severe drought 1994/95 Many SADC countries were hit by the worst drought in memory,

surpassing effects of the 1991-92 drought in some parts of the region 1997/98 Normal rainfall throughout region although impacts of El Nino were

significant. 2002/03 Significant drought in the SADC region, particularly from Zimbabwe

northwards According to the Lower Limpopo Assessment, the last severe droughts prior to 2002 occurred in 1991/92 and 1994/95 (Table 5.2). These droughts aggravated the already low flows in the Limpopo River systems caused by the very high levels of water abstraction, particularly in South Africa. These two factors have changed the Limpopo from its historical state of a perennial river to one with predominantly seasonal flow (Ashton et al. 2001). Low river flows, whether due to drought or abstraction or both, result in additional stresses on the ecosystems, particularly during winter because they restrict the available habitat, the concentration of ions and other compounds may increase (particularly salinity in the lower Limpopo), water temperatures may rise, and turbidity may increase, restricting light penetration and visibility. An example is the restriction of fish to permanent pools and similar



situations where they compete with the wildlife for living space (Joint Upper Basin study in SARDC/IMERCSA/ZERO 2002). Persistent lower flows will also result in vegetation changes such as Phragmites encroachment (Carter and Rodgers 1989). High flows, but not necessarily floods, are needed to stimulate some aquatic organisms to breed so low flows can constrain breeding. The effects of these reductions on the riverine and floodplain vegetation have not been well documented. Riverbank vegetation along the lower Levuvhu River has died back, including large fig (Ficus) trees and some species which grow in local depressions and sinkholes in sections of the river with near-surface or surface bedrock sections, notably Syzygium and Breonadia trees (Deacon 1990 in SARDC/IMERCSA/ZERO 2002). This happened at a time when the flow reductions due to developments upriver were aggravated by a drought so it is difficult to determine cause and effect. A regional review suggests that aquifer recharge will respond non-linearly to drought so that a relatively small decrease in rainfall may result in a disproportional and significant reduction in recharge (Beekman et al. 1996; Figure 5.9). National rainfall statistics for Zimbabwe reveal that five periods of below national average rainfall have been experienced, the most severe one and also of longest duration, being during the early to mid 1990s (Fig 5.10). Over the period 1990 to 1998 the annual deviation from the mean was close to 100 mm/year. The Limpopo basin in Mozambique presents a high risk of agricultural drought, depending on the type of dryland cropping system in place (Gomes and Famba 1999; Ashton et al 2001). The timing of the beginning and end of the effective rains is very variable which, combined with the unpredictable intervals between rainfall events, makes the lower Limpopo a very high-risk dryland agricultural zone (crop failure likely in 75-90 percent of years).

y = 148 ln(x) - 880

0.1

1

10

100

1000

0 500 1000 1500

Annual rainfall (mm)

Rec

har

ge

(mm

/yr)

Figure 5.9: The relationship between annual recharge and annual rainfall in Southern Africa (after Beekman et al., 1996). Note the logarithmic scale on the recharge axis. The solid line represents a

fitted relationship and the dotted line a more “optimistic” interpretation.).



Figure 5.10: Zimbabwean National rainfall deviation from the mean for the period 1910 to 2000 (www.grida.no/climate , 2002).

5.2.7 Floods The Limpopo River has been subject to flooding several times during the period of the historical record, mainly due to high rainfall in the upstream countries (Table 5.3). The highest instantaneous peak flow recorded at Chokwe in Mozambique was 7 800 m3/sec in February 1955 (UNEP, PAP/RAC, MICOA 1998). The highest peaks are most likely to occur when floodwaters from the Olifants and Limpopo coincide, resulting in extensive flooding of the lower river course with its shallow gradient and extensive low-lying floodplains. A flood caused by Cyclone Bonita in February 1996 reached a maximum daily flow of 3 368 m3/sec causing severe flooding and drowning several people. Heavy rains occurred over southern Africa from about 26 January to 28 March 2000 reaching a peak with the arrival of Cyclone Eline on the eastern coastline on 22 February. The high rainfall and flooding resulted in the displacement of about 733 000 people in northern South Africa and southern and central Mozambique, and the drowning of 929 (GREFE 2000; UWHRG 2000). The cost of crop losses and damage to infrastructure and dwellings amounted to hundreds of millions of US Dollars. Flooding has significant negative and positive impacts on ecosystems, both directly and indirectly (Carter and Rodgers 1989; Rodgers 1995; Jewitt, GPW et al. 1998). The direct impacts include inundating large areas of vegetation that is not adapted to prolonged inundation, recharging of groundwater, flushing of salts in saline areas, and stripping the riparian vegetation, depositing large sediment loads and providing opportunity for vegetation rejuvenation to begin. Indirect impacts include altering the habitat for the fauna by changing the proportions of rock and sediment on the river bed, depriving terrestrial and aquatic animals of the shade and shelter and breeding habitat provided by the fringing vegetation, and exposing and creating large areas of bare sediment for colonisation by invasive introduced plant species.



Table 5.3: High rainfall periods and floods in southern Africa (Preston and Tyson 2000; Ashton et al. 2001; SADC/IUCN/ZRA/SARDC 2000 in SARDC/IMERCSA/ZERO 2002

Period Notes 1893/94 High rainfall

1915 Major floods in South Africa 1955 High rainfall

1971/72-1980/81 High rainfall over much of southern Africa; 1974 the rainfall was >100% of the mean throughout the region.

1984/85 Near normal seasons; some recovery from the drought of previous three years

1995/96 High rainfall throughout most of the SADC region

1999/2000 High rainfall and Cyclone Eline bring widespread floods to the region; significant flood damage is caused in all the Limpopo basin countries

5.2.8 Global warming Global warming will affect circulation patterns over southern Africa but the net effects on rainfall are difficult to predict reliably because they may be affected by changes in ocean currents and aerosols from savanna fires and pollution (Lutjeharms et al. 2001; Tyson and Gatebe 2001). Mean annual, and annual mean maximum, air temperatures have been increasing steadily over the past century, with a maximum increase of nearly 2°C in the interior while the southeastern coastal region of South Africa has cooled by nearly 1°C (Tyson and Gatebe 2001). There is no conclusive evidence of similar trends in rainfall, largely because these are masked by the inter-decadal cycle in rainfall described and evident in Tables 5.2 and 5.3. The intensity of earlier extreme events, particularly heavy rainfall, has increased significantly over South Africa (Schulze et al. 2001; Tyson and Gatebe 2001). Rainfall may decrease by between 0 and 15% over most the catchment and by more than 15% in the area of the basin east and west of the border between Zimbabwe and Mozambique and north of Pafuri (Schulze et al. 2001). Both summer and winter minimum temperatures in are expected to rise between 2°C at the coast and 3.5° in the interior with maximum temperatures rising 1-2°C and 1°C respectively (Joubert and Kohler 1996). Potential evaporation is expected to increase 6-8% over most of the Limpopo Basin and by 8-12% over the higher rainfall areas in South Africa and Zimbabwe (Schulze et al. 2001). This will have a significant impact on runoff and amplify the impacts of the already high year-to-year and longer-term variations in rainfall. Thus, low flows during droughts may be significantly reduced and, conversely, the size of floods is likely to increase during wet periods. There is considerable uncertainty in these predictions though because changes in the rain producing Indian Ocean atmospheric systems may result in a net increase in rainfall. In the Limpopo basin, major floods occurred in 1893 and 1894 followed by the record flood of 1915 (SARDC/IMERCSA/ZERO 2002). The next major floods occurred more than 50 years later, except for those in the late 1930s and 1950s which coincided with Hale cycle peaks. The occurrence of cyclones Demoina in 1984 (main impacts south of the Limpopo Basin), Bonita in 1996 and Eline in 2000 brought heavy rains and severe floods. These do not provide conclusive evidence of a trend but they do support the argument that the observed changes should increase the size of the cyclone formation zone in the Indian Ocean, and that the warmer ocean and higher air temperatures will lead to storms bringing more, and more intense, rainfall.



5.3 Drainage Basins 5.3.1 General description In effect the Limpopo River is an ephemeral or non-perennial river with very irregular flow periods. It is only during high rainfall periods that continuous flow over sections of the river is experienced. In contrast, during extremely high rainfall in that part of the catchment that supplies the lower reaches of the Limpopo River (eastern escarpment of South Africa), large areas of the southern Mozambique coastal plain can become inundated to a depth of up to 7 m. Such a condition occurred during February 2000 (Dyson and van Heerden, 2001). For the purpose of this discussion the Limpopo basin is divided into three logical reaches: the Upper Limpopo River Reach, the Middle Limpopo River Reach and the Lower Limpopo River Reach. The Upper Limpopo River Reach stretches from south of Lobatse to the confluence with the Shashe River, a distance of about 500 km. Over this reach the river, forms the boundary between South Africa and Botswana. The Middle Limpopo River Reach, a distance of approximately 200 km, covers the section from the confluence with the Shashe River up to the Mozambique/South Africa/Zimbabwe border at Pafuri. This reach of the river marks the boundary between South Africa and Zimbabwe. The final reach, representing a distance of approximately 400 km from Pafuri to the coast at Xai-Xai, is referred to as the Lower Limpopo River Reach and is entirely located within Mozambique. In Botswana the Limpopo basin is subdivided into a number of sub-catchments (Table 5.4). In Mozambique the northern boundary of the Limpopo basin is defined by the watershed of the Save River and in the south by that of the Incomati River. The main tributaries of the Limpopo in Mozambique are the Changane (left flank) and the Elephantes River on the right flank. The South African part of the Limpopo Basin consists of two primary drainage regions: region A which comprises the secondary drainage regions of the Limpopo and the Marico-Crocodile, and region B which comprises the secondary drainage regions of the Levuvhu and the Olifants. In Zimbabwe the primary catchment of the Limpopo Basin is referred to as the Drainage Region B and includes the Shashe (shared with Botswana), the Umzingwani, Bubye and Mwenezi rivers. Details of the major tributaries in each reach of the Limpopo River are listed In Table 5.4.

Table 5.4: Major tributaries to the Limpopo River in the Upper, Middle and Lower Reaches of the Limpopo River and the countries where they join the Limpopo.

Tributaries joining the Limpopo River Limpopo River Reach Botswana South Africa Zimbabwe Mozambique

Approximate catchment area (km2)

Upper

Notwane Bonwapitse Mahalapswe Lotsane Motloutse

Marico Crocodile Matlabas Mokolo Lephalala Mogalokwena

199 350

Middle Shashe

Sand Nzhele Nzhele Luphephe Luvuvhu Olifants

Mutshilashokwe Umzingwane Shabili Bubye

75 750

Lower Mwenezi

Mwenezi Olifants Changane Lumane

142 250



5.3.2 The Upper Reach Five tributaries join the Limpopo River from Botswana and six from South Africa (Table 5.4). The total catchment area of the Upper Limpopo River Reach is close to 148 669 km2. Various studies have been conducted in the past and of particular importance for the present project are the:

• Joint Upper Limpopo Basin Study Stage I (JULBS) completed in 1991; • Botswana National Water Master Plan (BNWMP) completed in 1991; • Hydrological Modelling of the Limpopo River Main Stem completed in 1999; • The summary of the water resources given in the first draft of the South African

National Water Resource Strategy of 2002. Some of the key findings pertaining to the surface water resources of this section of the Limpopo contained in these documents are listed below:

• The total catchment area for this region is 148 669 km2 with a naturalized mean annual runoff of 1 432.5 x 106 m3. By 1990, 863.2 x 106 m3 of this flow had already been utilised.

• The development of water resources in the tributary catchments has resulted in a significant reduction in the mean annual runoff to the Limpopo main stem, with further decreases expected in the future.

JULBS (1991) was conducted for the Joint Permanent Technical Committee (JPTC) on Water Affairs of the republics of Botswana and South Africa. This study was commissioned to: evaluate the present utilization and availability of water in the Limpopo River down to its confluence with the Shashe River; determine the potential and demand for development and determine and evaluate the most successful and cost effective method of regulating the river in order to stabilize existing water use and promote further development. Since the completion of this study, significant developments have taken place and some are planned on the tributaries contributing to the Limpopo river flow. In 1999 this report was updated by a study which covered not only the same section as the JULBS, but extended to Chokwe on the lower Limpopo River in Mozambique. On the Botswana side, the major development since JULBS (1991) has been the construction of the Letsibogo Dam on the Motloutse River in 1997 (the principal dimensions of the dam are: catchment area; 5,693 km2, annual inflow: 57.44 x 106 m3 and active storage 100 x 106 m3. The Letsibogo Dam is the first development for the supply of water to the North South carrier for the transfer from North Eastern Botswana to the greater Gaborone. Additional studies are in progress for evaluating the feasibility of damming the flow in other tributaries such as the Tati, Thune, Lotsane and lower Shashe for water supply and irrigation use. A revised assessment of the availability of the water, its utilization and impact on Limpopo flows and groundwater storage will need to be conducted in view of developments done so far and the ones that are most likely to be implemented in future in Botswana as well as in South Africa. Catchment parameters will need to be recalibrated in view of additional hydrometeorological data that has been obtained since 1991 and also in view of impact caused by damming and other human activities that may render certain areas susceptible to drought. Most of the economic activity of Botswana is centred around the eastern boundary with South Africa. As in the past, the Botswana part of the Upper Limpopo River basin will continue to play a critical role in the provision of water for both human consumption and agriculture to meet the growing needs of Botswana. In the eastern part of Botswana, the rivers drain in a general easterly direction, flowing into the left bank of the Limpopo River, which forms the international border between Botswana and South Africa. 5.3.3 The Middle Reach



Apart from the Shashe River, only two major rivers join the Limpopo River from the north in this reach (Table 5.4). These are, from west to east, the Umzingwane and the Bubye. From the southern side only three major rivers join the Limpopo River over the middle reach. These are (from west to east) the Sand, Nzhelele and the Levuvhu Rivers. The upper reaches of the rivers originating in Zimbabwe are closer to the major settlement areas and are the most developed areas of these rivers. The Umzingwane River does, however, have a dam in the lower reaches, close to Beit Bridge. Some 6 120 ha of irrigation has been developed along the banks of the Limpopo River between the confluence with the Shashe and Beit Bridge with water being extracted from the Limpopo River and boreholes tapping mainly the alluvium associated with the river (Boroto & Görgens, 1999). The major portion of this is on the South African side (~5 600 ha; du Toit, 2003). There are no major dams in either of the rivers draining the catchment between the Shashe confluence and Beit Bridge, with only a number of small farm dams on the South African side. The area that drains from Zimbabwe into the Limpopo River is one of the driest parts of Zimbabwe. Rainfall in most parts of this area, especially close to Beit Bridge, is not enough for any food production. In addition, the region has a poor groundwater potential although rural water supplies have relied on this source. Much of the Sand River catchment has been affected by development, both urban and agricultural. The catchment contains more than 700 small farm dams used mainly for stock watering and intensive irrigation, almost exclusively from groundwater resources, but often adjacent to rivers. The Nzhelele River catchment contains two large dams (Nzhelele and Albasini) and more than 80 small farm dams. Water use in this catchment is mainly for domestic, agriculture, forestry and game farming, but further development is restricted due to limited water resources. 5.3.4 The Lower Reach Four major tributaries to the lower Limpopo River flow into the Limpopo River in Mozambique. One of these, the Rio Changane, originates on the Mozambique-Zimbabwe border and drains the northeastern portion of the lower Limpopo catchment. The Nuanetzi River (also referred to as the Mwenezi) rises in the Zimbabwe highlands where one major dam, the Manyuchi Dam with a capacity of 315 x 106m3 has been constructed. It joins the Limpopo about 50 km downstream of Pafuri. The other two, the Levuvhu and the Olifants Rivers originate in South Africa. The Levuvhu River drains a relatively small area of about 3 600 km2 and joins the Limpopo at Pafuri. Considerable development has occurred in this catchment and land use ranges from commercial agriculture and forestry to subsistence agriculture and game farming. The Olifants River drains large areas of the Mpumalanga Province in South Africa and is one of the largest tributaries of the Limpopo River. Three large dams are constructed in the river, the Witbank and Loskop dams in South Africa, and the Massingir dam in Mozambique. The Olifants River, up to the Massingir dam, drains an area of about 68 500 km2. River water quality is severely degraded by the coal mining industry in its upper reaches (Ashton et al. 2001). 5.4 Surface Water Resources and Hydrological Modelling of the Limpopo Basin As a follow-up to the 1990 Joint Upper Limpopo Basin Study, Boroto and Görgens (1999) configured a multi-catchment and multi-reservoir flow model for the Limpopo Main Stem up to Chokwe. The model incorporated modules for rainfall-runoff, reservoir inflow, demand, outflow and evaporation, abstraction and point discharge functions, channel loss using a



sand-reservoir/riparian consumptive use concept, and a model to estimate the streamflow reduction due to afforestation. The results from the model are summarized in Table 5.5. There are five dams present in the Botswana section of the Limpopo Basin. These are the Gaborone, Nnywane, Shashe, Bokaa and Letsibogo Dams with a total storage capacity of 349 x 106m3. These dams contribute to the water supply system of eastern Botswana managed by the Water Utility Corporation (WUC). Four new dam projects are in the feasibility assessment stage: Lotsane River (agriculture and water supply), Lower Shashe-Dikgatlhong dam (water supply), Thune River and Tati River. Botswana has to date relied on groundwater as the main source of supply to all demand sectors of the economy. About 50% of Botswana’s domestic water supply comes from groundwater. Rapid population and economic growth has led Botswana into water supply deficit, calling for a change in water development strategies from the use of groundwater sources to the development and use of dams (LBPTC, 2001). The mean monthly flow at Chokwe over the period 1971 to 1995 is shown in Figure 5.11.

Table 5.5: Flow balance details of the Limpopo Main Stem for the period 1971-1995 (all figures in 106m3/a).

Component Upstream

of Sterkloop

Sterkloop to Shashe

Shashe to Beit

Bridge

Beit Bridge to

Pafuri

Pafuri to Chokwe

Inflow: Main stem upstream

0 497 608 1 369 1 833

Inflow: Tributaries 720 305 1 182 599 1 940

Study area runoff 15 22 8 15 90

Total entering reach 734 824 1 799 1 982 3 864

All abstraction: Main stem and lower sections of tributaries

82 53 15 18 517

Alluvial channel and riparian losses

110 163 416 132 188

Expected at flow gauging station 541 608 1 369 1 833 3 159

A major recent development in water supply was the recent completion of the North South Carrier project. It is the largest water project and the largest single infrastructure project ever undertaken in Botswana and was completed at a total cost of P1.5 billion. The pipeline now connects the cities and towns along the eastern margin of the country as well as all of the major water supply dams. The project was completed and operation of the pipeline turned over to WUC. Numerous small and medium size dams have also been constructed along various tributaries throughout the basin under the auspices of the Ministry of Agriculture for both livestock and small-scale irrigation. It is reported that many of these dams are considerably under-utilised at present and the Ministry of Agriculture is planning a project to evaluate the dams and increase their usefulness.



0

200

400

600

800

1000

1200

1400

1600

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month

Mea

n m

onth

ly f

low

(M

m3)

Figure 5.11: Mean monthly flow at Chokwe over the period 1971 to 1995 in x 106 m3/a. The largest dam in the Limpopo Basin in Mozambique is the Massingir Dam in the Elefantes River. This dam has a storage capacity of 2 256 x 106 m3 with an annual discharge of 1 800 x 106 m3. The main purpose of the dam is to provide water for irrigation. The only other reservoir in the Limpopo are weir gates at Macarrentane with an annual discharge of about 5 510 x 106 m3. The South African part of the Limpopo Basin is divided into four Water Management Areas (WMAs). These are based on the major catchments and are referred to as the Limpopo, the Levuvhu/Letaba, the Crocodile/Marico and the Olifants WMAs. Recent published figures for the total water resources in these WMAs (NWRS, 2002) are listed in Table 5.6. These figures only refer to the South African land area and have to be integrated with those for the neighbouring countries to determine the total water resources of the Limpopo Basin. Groundwater is responsible for more than 90% of the water supply to Xai-Xai, the largest town in the region. A large proportion of the flow in the Limpopo was contributed by tributaries that rise in South Africa (Table 5.6). Almost all of the surface water runoff is allocated to various so users so that, even though there are schemes which transfer additional water into the catchment, there is still a deficit of about 600 x 106 m3 per year. Available groundwater resources are estimated to be approximately 352 x 106m3 per year which will lower the water deficit to approximately 250 x 106 m3 per year.

Table 5.6: Estimated water resources of the Limpopo Basin as per local major catchment or country. Data extracted from the draft copy of the SA National Water Resource Strategy(all figures in x 106m3

per year).

Available resources

Natural

WMA / Major

catchment

Mean Annual Runoff (MAR)

Surface water

Usable return flow

Reliable yield Transfer

Require-ments Balance

Limpopo 985 160 24 184 19 325 -122 Levuvhu / Letaba 1 185 243 23 266 -13 334 -81 Marico/Crocodile 855 202 380 582 646 1328 -100 Olifants 2 042 409 103 512 164 971 -295 Total 5 067 1 014 530 1 544 816 2 958 -598



6. WATER USE AND DEMAND IN THE LIMPOPO BASIN Reliable figures for sectoral consumption and demand are not readily available and vary from country to country. In order to obtain a perspective on the water demand and use within the Limpopo Basin the following broad classification was used.

• Urban and industrial. This includes the water use in and around the larger cities and towns.

• Rural domestic. This represents all water used by the rural communities in their daily routines.

• Agriculture; this includes both livestock and irrigation requirements. • Mining • Power generation • Afforestation

6.1 Botswana Urban/industrial drinking water supply is the largest and fastest growing sector of water use in the Limpopo basin of Botswana. Growth in demand for potable water between 1990 and 2020 was estimated to be close to 100 x 106m3. The current annual use is estimated to be around 60 x 106m3. The north-south carrier project, by greatly improving water availability along its over 400 kilometre route also may significantly enhance water demand through increased economic activity along this corridor. The total area of developable soils in Botswana is 79 300 ha (793 km2) in the upper Limpopo Basin (MacDonald Shand Consortium, 1991). However, at present there is relatively little irrigated farming in Botswana, even along the Limpopo River. The total irrigated area along the Botswana bank of Limpopo was 1 500 ha in 1985, which reduced to approximately 900 ha in 1990 due to continued drought (MacDonald Shand Consortium, 1991). Over the years, the Ministry of Agriculture has put in place a number of agriculture programmes with the aim of promoting rain fed, irrigated and dairy farming by providing an enabling environment for farmers and producers. Most of the planned irrigation with fresh water is based on existing boreholes, wells, dams or riverside pumps. It has been estimated that only 2 000 ha is required to satisfy vegetable requirements for the country over the next ten years. At present irrigated agriculture consists mostly of horticulture, which is dominated by a few, relatively large-scale commercial farms in Tuli Block that have the advantage of high yielding boreholes and good soils along the Limpopo river. These farms also use water from the river during the few months in the year when there are flows. The rest of the horticulture sub-sector is fragmented, comprising numerous small farms, mostly 1 ha or less, mainly because of low borehole yields. This tends to deny growers the potential economies of scale, including the possibility of dealing with market fluctuations and high post-harvest and transportation costs. The total area devoted to horticulture production at present is less than 1 000 ha. According to survey of existing horticultural farms, the total pumping capacity of existing boreholes and “sand-river” wells that have been licensed to irrigation amounts to about 20 million cubic meters per year, while the estimated present total water utilisation is 6-7 million cubic meters per year (NAMPAAD, 2002). The main irrigation activities and future plans for specific areas in the basin are summarised as follows:



• Along Limpopo – Marico River: Farmers are using existing water rights for irrigation. No more additional water rights have been planned for this area; specific water use figures not available).

• In Mahalapye area: apart from existing water rights, some more water rights will be given to the farmers.

• Talana farm, Tuli block (from 1997 report): located at the confluence of Limpopo and Motloutse river. 500 hectares are cultivable. Source of water is 10 boreholes located on the sand aquifer on the riverbed. Water rights (including Seleka Farm) are 15.6 MCM per year. Water used in the year 1997 was 3.9 MCM.

• Seleka Farm, Tuli block (from 1992 report): Sources of water are 8 boreholes located on the sand aquifer on the riverbed and surface water from Limpopo river. Water used in the year 1992 was 452 000 m3 from boreholes. Water rights are 485 000 m3 per year. Additionally the total surface water used was 40 000 m3 in 1992. The same water rights are being used in Talana and Seleka farms. No more water rights have been planned for the farms.

• Motloutse River: There are more potential in terms of farming in the areas (Bobonong and surrounding areas like Phikwe, Mmadinare, Sefophe and others) close to this river. Additional water rights to be allocated to the farmers for irrigation in these areas have been planned.

The planned Lotsane dam is being evaluated for its feasibility to provide water for irrigation purposes. The majority of livestock in the Limpopo Basin receive their drinking water through boreholes and shallow open wells located in the river alluvium. As indicated in the 1990 estimates (Table 6.1), little growth is expected in livestock demand in the Limpopo Basin No actual water consumption figures for Botswana are available, however, demand forecasts for 1990 and 2025 are available as well as some water distribution figures of the Water Utilities Corporation (WUC) of Botswana is available. The total population living within the Botswana part of the Limpopo Basin was estimated (JULBS, 1990) to be approximately 750,000. Existing and future demand for the Limpopo Basin within Botswana was also previously estimated in 1990 (JULBS, 1990) and the figures are presented in Table 6.1. All urban centres and most major villages in the Limpopo Basin (i.e. Mahalapye, Palapye) are supplied by the Water Utilities Corporation (WUC), a parastatal entity. The WUC operates most of the dams in the Limpopo Basin as well as the North-South Carrier pipeline which interconnects the major populations centres in eastern Botswana. In the operational year 2001-2002, WUC supplied a total of 44 x 106 m3 of water derived from the Limpopo Basin to its customer base. This is up from 38 x 106 m3 in the 2000-2001 operational year.

Table 6.1: Demand Forecasts for the Botswana section of the Limpopo Basin.

Water use category Demand (m3 106/yr), 1990 Demand (m3 106/yr), 2020 Urban/Industrial 21 118 Rural domestic 4 9 Livestock 15 18 Irrigation 12 32 Power station/ mining 9 21 Total 61 198

Water supply to some major and most of the small villages in the basin is primarily from groundwater based systems. These include some relatively large wellfields such as that supplying Molepolole. The vast majority of the systems, however, are small village based



supplies with two or more boreholes equipped with diesel driven pumps. The total supply provided by these systems is not easy to estimate, however if one considers that rural water supply is presently about 12% of urban water supply (Table 6.1), then present rural water supply in the Limpopo Basin is approximately 5.3 x 106 m3 per annum. One privately operated wellfield (Paje wellfield), run by the parastatal Botswana Power Corporation (BPC), is present within the Limpopo Basin. Operation of the wellfield is moni-tored by the Water Apportionment Board (WAB) of the Department of Water Affairs, to which annual reports are submitted as part of the licensing of abstraction. Water supply is from 9 boreholes with a total annual abstraction has been approximately 600 000 m3 for the last six year (Paje wellfield monitoring report, 2000). No more water rights have been planned. 6.2 Mozambique Boroto and Görgens (1999) refer to the information contained in the Mozambique National Irrigation Development Master Plan of 1996. The Chokwe Irrigation Scheme comprised at that stage an area of some 29 000 ha representing an annual abstractions of about 846 x 106m3. 6.3 South Africa Table 6.2 summarizes the water requirements within the South African section of the Limpopo Basin. This information was extracted from the Draft National Water Resource Strategy of SA (2002). A recent assessment made by the SA Department of Water Affairs and Forestry produced figures for the use of groundwater in the Limpopo Basin (pers. comm W H du Toit, 2003). These are reflected in Table 6.3.

Table 6.2: Statistics on annual water requirements within the Limpopo Basin of South Africa for the year 2000 (x 106 m3)

Water

Management Area

Irrigation Urban Rural Mining

and bulk industrial

Power generation Afforestation Total

Limpopo 238 37 28 14 7 1 325 Levuvhu/Letaba 248 11 31 1 0 43 334 Marico/Crocodile 445 691 38 127 27 0 1 328

Olifants 557 92 44 94 181 3 971 Total 1 488 831 141 236 215 47 2 958

Table 6.3: Statistics on the current annual ground water use the Limpopo Basin of South Africa (x 106

m3) (WH du Toit, DWAF, Pers. Comm.)

Water Management

Area Irrigation Livestock

Rural Communities Municipalities Mining Total

% of Total

Limpopo 131 3 53 12 9 208 45 Levuvhu/Letaba 9 0.2 38 8 2 57.2 12.4 Marico/Crocodile 56 3 6 8 10 83 18 Olifants 79 2 20 2 11 114 24.6 Total 275 8.2 117 30 32 462.2 100



From Table 6.3 it is clear that the largest use of groundwater in the Limpopo Basin is for irrigation. The major irrigation schemes are listed in Table 6.4.

Table 6.4: Major irrigation areas using groundwater resources in the Limpopo Basin

Irrigation from groundwater in the Limpopo basin of South Africa

Geographic area Hectare under irrigation Million m3 / annum

Northern Springbok Flats 8 900 43 Sand River 8 700 42 Southern Springbok Flats 7 500 36 Upper Crocodile* 6 500 31 Pontdrift/Weipe* 5 600 55 Lower Crocodile* 5 200 25 Dendron 4 700 23 Mooketsi* 1 000 5 Altona 850 7 Louis Trichardt 420 2 Letsitele* 420 2 Levuvhu* 420 2 Taaibosch 180 1 Beauty / Marnitz 180 1 TOTAL 50 580 275

6.4 Zimbabwe In the Zimbabwe section of the Limpopo Basin very little information of water use is available. The arid nature of the area within Zimbabwe restricts irrigation to mainly run-of-river irrigation from the Limpopo and its major tributaries (Tuli and Umzingwani). In the report by Boroto and Görgens (1999) areas under irrigation are cited based on information supplied by the Zimbabwe Department of water Resources in 1997. According to this source some 640 ha and 3 840 ha are under irrigation in the Tuli River and Umzingwane River catchments respectively. Based on the figures of Boroto and Görgens (1999) and du Toit (2003), there is an additional 520 ha under irrigation on the Zimbabwe side of the Limpopo River. Irrigation areas within Nwanedzi/Luphephe and Mwenezi Rivers is estimated at 1 000 and 22 000 ha respectively. Consumption figures for domestic, industrial, mining and rural use of water in this part of the Limpopo Basin are unfortunately not available. Rural communities mainly use groundwater for domestic purposes. Commercial and economic use of groundwater is on a very small scale. No records of volumes of groundwater abstracted in the basin exist. There are unsubstantiated reports of conjunctive use of groundwater and surface water by some farmers in the area.



7. GEOLOGY This section contains a summary of the major geological features in the Limpopo River Basin. 7.1 Major Geotectonic Divisions The major geographic division of Limpopo drainage-basin geology lies between the Archaean to Mid-Mesozoic formations of South Africa, Botswana and Zimbabwe, on the one hand, and the Mesozoic to Cenozoic formations of the Mozambique Coastal Basin (Du Toit et al., 1997), on the other (Figure 7.1). For the purposes of a simple but workable scheme of hydrogeological regions (Vegter, 2001) or hydrostratigraphic units that can be consistently applied throughout the Limpopo drainage basin and extended into the wider SADC region, the descriptive geology of the basin will follow this fundamental division. Over most of the SADC countries, the hydrogeological setting is mainly similar to the Archaean-Mesozoic region of the Limpopo Basin, but there are coastal regions of South Africa and Tanzania on the eastern side of Africa, and South Africa, Namibia and Angola, on the western side, where hydrogeological settings similar to that of the Mozambique Coastal Basin occur. A further notable feature of major tectonic significance, which is of even greater importance over a major part of the SADC region in East Africa, is the extension of the great East African Rift System (EARS) into the lower portion of the Limpopo drainage basin, around the Changane River tributary. This southern extension of the EARS along part of the Nubia-Somalia (NB-SM) plate boundary (Hartnady, 2002) is most evident on earthquake epicentre maps of the subcontinent south of 150S and appear to be associated with the neotectonic reactivation of major crustal faults. The key hydrogeological aspect of this Late Cenozoic neotectonic reactivation is the concurrent distribution of significant hot springs and other geothermal phenomena along these particular structural lines. The Tshipise and Klein Tshipise hot springs in the Limpopo Province of South Africa are the prime examples. To the extent that this deep circulation system may, in periods of extreme drought, be amongst the most perennial and enduring of all the groundwater resources in the Limpopo groundwater basin, and similarly for other parts of the EARS in the wider SADC region, it will be worthy of special investigative consideration within the framework of the future larger GEF project. However, the deeply circulated thermal waters are notoriously brack to saline, or even hypersaline in some places. Yet another hydrogeologically relevant aspect of the Limpopo drainage basin is directly attributable to Late Cenozoic tectonics and EARS propagation into Southern Africa, between the Urema-Mazenga rift system in Mozambique and the Okavango rift system in Botswana. This aspect is the geologically recent, tectonic truncation or “beheading” through swell uplift of the palaeo-Limpopo drainage, which at its maximum development extended far into the interior plateau of Angola (Summerfield, 1998). The important aspects of this key stage in the evolution of the Limpopo drainage, relate to: (1) Possible basement/tectonic control on the main axis of the proto- or palaeo Limpopo

River by the giant Okavango Dyke Swarm (recent 2002 references), emplacement of which shortly preceded the break-up of the Gondwanaland supercontinent around a “failed triple junction” in Southern Mozambique;

(2) Potential vertically-stacked association of this basement dyke swarm, locations of the late- or post-Karoo rift basins in Botswana, and the Tertiary depocentres of the Kalahari basin and superimposed Late Tertiary flood-plain alluvials of the palaeo-



Limpopo along the (Motloutse River) connection between the lower Limpopo and its former Okavango headwaters.

Figure 7.1: Simplified geological map of the Limpopo basin showing the major geological units and the broad divisions between the Archaean-Mid-Mesozoic of Botswana, South

Africa and Zimbabwe (pink, purple, yellow and brown) (Section 8.2) and Mozambique Coastal Basin (Section 8.3) (yellow) clearly. (Map prepared from USGS information).

An improved understanding of these now-fossilised hydrogeological settings beneath the Okavango-Limpopo divide, and how they might be further developed for drought relief purposes at present and in the future, may provide important information for similar, but still active settings in the other large rivers of the wider SADC region, such as the Zambezi, Shire or Rovuma systems. It is here relevant to note that by 1990 the surface-water resource of the Motloutse catchment in Botswana was fully developed to the limit of the naturalised mean annual runoff; cf. Linn, 2002. 7.2 Western Archaean-Mesozoic Complexes and Kalahari Basin The major part of the Limpopo drainage basin in Botswana, South Africa and Zimbabwe is underlain by three generalised types of geological terrain, viz., Archaean-Early Proterozoic crystalline (igneous and metamorphic) basement, Late Archaean-Mesoproterozoic volcano-sedimentary basins and layered intrusives, and Palaeozoic-Mesozoic (Karoo) sedimentary-volcanic sequences in localised basins, structurally controlled by Mesoproterozoic faults and shear zones. In addition, the Karoo basins along the western drainage divide in Botswana are overlain, and to some degree concealed, by marginal parts of the Cenozoic Kalahari Basin.



The distribution of the major stratigraphic units (Table 7.1) is shown in Figure 7.2 and a schematic geological cross-section is given in Figure 7.3. A brief description of the main geological subdivisions is provided below. 7.2.1 Archaean-Early Proterozoic basement The Archaean-Early Proterozoic (Swazian-Randian-Vaalian; Table 7.1) basement complex in South Africa, Botswana and Zimbabwe regions of the Limpopo drainage consists of two cratonic blocks (the Kaapvaal and Zimbabwean cratons) and an intervening Archaean-Early Proterozoic mobile belt (the Limpopo Mobile Belt, Figure 7.3). 7.2.1.1 Kaapvaal and Zimbabwe cratons In these hydrogeological regions, the aquifers are dominantly of the “fractured-and-weathered” type, namely, “regolith aquifer” zones of generally shallow vertical extent, except where zones of heavily dyke-intruded and fractured basement may provide potential preferred flow-paths for more deeply circulating groundwaters. In these terrains the granite/greenstone belt distinction is important, mostly from a hydrogeochemical perspective; for example, relating to potential hazards of high fluoride in granitic groundwaters and toxic trace elements such as arsenic and lead in greenstone-derived groundwaters. The Great Dyke of Zimbabwe is a major feature of the country extending approximately north-south for 500 km and with a width of up to 5 km. Only a minor part of it (~50 km) occurs within the Limpopo drainage basin (Figure 7.2). 7.2.1.2 Limpopo mobile belt The highly deformed, polymetamorphic Limpopo Mobile Belt is situated between the two lower-grade granite-greenstone cratons. It is subdivided into northern and southern marginal zones and a central zone, each with a distinctive geological signature, separated from each other and from adjacent cratons by well defined shear zones of up to 10 km width. The marginal zones contain rocks that are the high-grade equivalents of the adjacent granite-greenstone terrains and display ENE trending structures. In the Southern Marginal Zone for example, tonalitic gneisses envelope numerous disconnected slivers of highly deformed pelitic and mafic gneisses, together with minor ultramafics and magnetite quartzite. The Central Zone has north trending structures and a completely different stratigraphic sequence, representing equally high grade metamorphic phases but of a more shelf-like sedimentary origin. Within it the metamorphic grade decreases to the west-southwest, until the granulite grades give way to amphibolite facies in Botswana. 7.2.2 Late Archaean-Proterozoic sedimentary basins and layered intrusives The Late Archaean-Proterozoic supracrustal units are mainly confined to the southern part of the Limpopo drainage basin, between South Africa and Botswana (Figure 7.2). These are represented by the Transvaal-Griqualand West, Wolkberg, Waterberg, Soutpansberg basins and the major layered intrusive Bushveld Complex.



Table 7.1: Stratigraphic column for the Limpopo Basin geology

E

rath

em

Era Period Epoch Period (million years BP)

Formations / lithological units

Holocene 0.01 – 0 Holocene alluvials Quaternary Pleisto-

cene 1.8 – 0.01

Pliocene 5.3 – 1.8

(Palaeo-Limpopo continental alluvials)

Upper Miocene 24 – 5.3

Cenozoic

Tertiary Lower 65 – 24

Kalahari Basin younger deposits

Cretaceous 145 – 65 Kalahari Basin older deposits and kimberlitic intrusions

Jurassic 180 – 145

Karoo Volcanics (Lebombo Group, Drakensberg Group)

Mesozoic

Triassic 250 – 180 Upper Karoo Supergroup

Pha

nero

zoic

Palaeozoic

Carboniferous – Permian (Cambrian-Carboniferous hiatus) 530-250

Lower Karoo Supergroup -

Namibian 1080-530 ~550? Kimberlitic intrusions (Venetia)

~1300 Pilanesberg Complex

Palapye Group

Soutpansberg Group ~1900-1700

Waterberg Group Mokolian 2070-1080

~2000 U. Bushveld Complex Felsics (Nebo Granite, Rashoop Granophyre)

~2100 L. Bushveld Complex mafics (Rustenberg Layered Suite)

~2500-2300 Upper Transvaal Supergroup (incl. Pretoria Group, Rooiberg Group,

~2500 Chuniespoort Group (incl. Malmani Dolomite Subgroup)

~2600-2500 Basal Transvaal formations (Godwan, Groblersdal, Buffelsfontein, Black Reef, Wolkberg)

Vaalian 2620-2070

~2540 Great Dyke of Zimbabwe

Randian 2870-2620 Various sedimentary, volcanic and granitoid intrusive units

Randian-Swazian >3300-2620 Various granitoid (intrusive and metamorphic) basement complexes

Swazian >3500 – 2870 Various mafic (“greenstone belt”) to felsic volcanic and sedimentary supracrustal units

(i) Transvaal-Griqualand West basin

Within the southern part of the Limpopo drainage basin (Figure 7.2), three main divisions are represented within the northern part of the Transvaal-Griqualand West basin. The Basal Transvaal units (e.g., Wolkberg Group in NE South Africa, Buffelsfontein Group, Black Reef Formation) are dominantly quartzitic sedimentary formations with localised acid-basic



volcanics. Units such as the Wolkberg and Black Reef may constitute thin but extensive fractured-rock aquifers with good quality groundwater and local high yields.

Figure 7.2: Major stratigraphic subdivisions in the Limpopo Basin. From a hydrogeological perspective, the chemical sedimentary formations of the Chuniespoort Group are among the most important units, in both the Limpopo drainage basin and Southern Africa generally. The Malmani Dolomite Subgroup, which has its maximum development along the southern drainage divide of the Limpopo basin (here also the karstified African land surface”). A minor but important occurrence of dolomite is present in the very upper reaches of the basin along the border with South Africa near Ramotswa. Although these “karstified-fractured” aquifers represent very small percentages of the surface exposure in the Transvaal basin, their groundwater potential (including recharge along divides and uplands) is generally high and they represent an import groundwater resource. The upper Transvaal sedimentary and volcanic units (Figure 7.2) unconformably overlie the Chuniespoort and Lower units. They are mainly shaly formations with thinner quartzitic intercalations and a prominent volcanic unit (Hekpoort Basalt) in the Pretoria Group. The uppermost fractured-and-weathered zone is hydrogeologically significant, except possibly for thinner, confined quartzitic layers in favourable locations and structures. (ii) Bushveld Complex The Bushveld Complex is divided simply (Figure 7.2) into a lower mafic unit (Rustenberg Layered Suite) and upper felsic units (Rashoop Granophyre Suite and Lebowa Granite Suite). Apart from their layered, anisotropic or “bedded” structure, these rocks are hydrogeologically similar to granite and greenstone crystalline areas, and constitute “regolith aquifers of variable thickness in the fractured-and weathered zone.



Soutpansberg

U. Limpopo

L. Limpopo

Indian Ocean

Lowveld

Karoo volcanic basement

Cretaceous formations

Mozambique Coastal Basin

Tertiary formations

Pleisto-Holocene alluvials

Pleisto-Holocene alluvials

Plio-Pleistocene alluvials and surficial regolith

Karoo volcanics

Lower-Middle Karoo sedimentary formations

Mokolian volcano-sedimentary formations

Vertically exaggerated Not strictly to horizontal scale

N Soutpansberg Trough

Archaean-Vaalian crystalline basement

Limpopo Mobile Belt

Giant Okavango dyke swarm (Karoo)

Kaapvaal Craton

Proterozoic dyke sets

Mokolian-Karoo basin border faults (neotectonic)

W

E Mazenga-Chissenga proto-rift swell

Figure 7.3: Schematic W-E Geological Cross-section



(iii) Soutpansberg-Waterberg troughs The Soutpansberg Trough separates the Southern Marginal Zone of the Limpopo Mobile Belt from the Central Zone (Figure 7.2). The northern boundary faults of the trough coincide towards the west with the Palala Shear, which together with the Zoetfontein Fault in Botswana is a structural control on the northern edge of the more extensive Waterberg Basin. Both the Soutpansberg Trough and the western portion of the Waterberg basin, crossing the border between South Africa and Botswana, have the form of structural half-grabens (see Soutpansberg cross-section in Figure 7.3) The Palapye Group occurs in an outlier basin north of the Sunnyside Shear (Figure 7.3) in Botswana. Another outlying basin of units roughly contemporaneous with these post-Bushveld strata, occurs between the Johannesburg Dome and the East lobe of the Bushveld Complex (Figure 7.2). 7.2.3 Palaeozoic-Mesozoic Karoo basins The Late Palaeozoic-Mesozoic volcano-sedimentary sequences (Karoo Supergroup) are less deformed than the underlying basement or the Mesoproterozoic strata, and are primarily sub-horizontally oriented. However, extensive block faulting is present with compartmentalisation of the Karoo units a very common feature. They are also extensively intruded by dykes and sills, including a major dyke swarm (“Giant Okavango Dyke Swarm”) trending WNW-ESE in the north of Botswana, southern Zimbabwe, and the northernmost part of Limpopo Province, South Africa. The Basal-Lower Karoo units (Ecca Group in South Africa, Wankie Sandstone and Madumabiza Mudstone in Zimbabwe, for example) act mostly as aquitards in which water quality locally can have high TDS and sulphate. The upper Karoo sedimentary formations (e.g., Forest Sandstone in Zimbabwe, Lebung Formation or Ntane Sandstone in Botswana and Clarens Formation in South Africa) contain groundwater under confined conditions, often at considerable depth. Spatially extensive outcrops of rhyolite and lava of the Drakensberg and Lebombo Groups formations represent the uppermost volcanic formations of the Karoo basins. 7.2.4 Cenozoic Kalahari basin The high percentage of porous aquifers across Botswana is due to the extensive presence of Kalahari Beds sand cover over much of the country. In northwestern parts of Botswana, the Kalahari Beds attain a thickness of >500 m, but it is much less along the drainage divide between the Limpopo and Okavango hydrological basin. Generally unconsolidated formations of the Kalahari Beds are saturated over their outcrop area and aquifers are often unconfined. Exploitation has been limited because of drilling and borehole construction difficulties, but water quality is generally good and the expected groundwater potential is high. In the area around the Motloutse River in Botswana, and other upstream tributaries on the left or west bank of the Upper Limpopo, there may be remnants of Late Tertiary fluvial deposits, dating from the time when the Okavango system (and possibly also the upper Zambezi system) was connected to the Limpopo drainage. Where clean sands are present in these palaeochannels and units are thick, groundwater potential may be high and the water quality good. These shallow aquifers are, however, vulnerable to pollution from surface sources.



7.2.5 Mozambique (Coastal Basin) Table 7.2 and its following text summarises the main features of lithology and stratigraphy in Coastal Basin of Southern Mozambique partly based on a report of the East African Regional Hydrocarbon Study (EARHS; Du Toit, Kidston and Slind, 1997). Table 7.2: Mesozoic-Cenozoic geologic time scale and stratigraphic units of southern

Mozambique

Era Period Epoch Period

(years before present)

Formations / lithological units

Holocene 10 000 – 0 years Holocene alluvials

Quaternary Pleistocene 1.8 – 0.01 million

Marine and lacustrine alluvials (Macia, Gondza and Inhaca Formations)

Pliocene 5.3 – 1.8 million (Continental alluvials)

Upper Miocene 24 – 5.3 million

Mazamba Fm Govuro, Jofane Fms Temane Fm

Oligocene 36 – 24 million Inharrime Fm. Eocene 58 – 36 million Cheringoma Fm.

Cenozoic

Tertiary

Lower Palaeocene 63 – 58 million Cheringoma Fm.

Upper Grudja Fm. Cretaceous Lower

135 – 63 million Maputo, Domo Fm.

Jurassic 180 – 135 million Karoo Volcanics Mesozoic

Triassic 230 – 180 million The sedimentary history of the broad coastal plain of Mozambique and northeastern South Africa is characterised by a number of regression and transgression cycles (Botha, 1997; Meyer and Kruger, 1988; Dingle et al, 1983) as a result of relevant sea-level oscillations since the Cretaceous (Miller, 2001). These oscillations varied from >+350 mamsl in the early Eocene to >-200 metres below mean sea level during the Miocene/Oligocene and Pliocene periods. During the first marine transgression in the Lower Cretaceous, argillaceous, glauconitic sandstones of the Maputo Formation were deposited, overlying the weathered Karoo basalts. The Domo Formation (Lower Cretaceous) and Grudja Formations (Upper Cretaceous), overlie the Maputo Formation. The Domo Formation consists of dark-grey to black coloured, thin bedded marly shales with rare sand streaks. The Grudja Formation consists predominantly of glauconitic sandstones (greensand), marls and calcarenites. The Cheringoma Formation (Eocene), consisting of algae-rich oolitic and nummulitic limestones, and argillaceous sediments of the Inharrime Formation (Oligocene to Lower/Middle Miocene), overlie the Cretaceous strata The Jofane Formation (Miocene), which predominantly consists of sandy limestones and dolomites (commonly with oolites and coral fragments), unconformably overlies the Inharrime Formation. Overlying the upper zone of the Jofane/Govuro succession (Table 7.2, in the lower Limpopo River region, the Mazamba Formation (Upper Miocene/Pliocene) is a continental/terrigenous unit with thickness >100 m in the western part, and is said to increase up to 600 m within Inhambane Province. It generally consists of sands to coarse sands (locally rich in pebbles), with intercalated clays. In outcrops along the margins of the



Limpopo River, between Mabalane and the confluence with the Uanetzi River, the Mazamba consists of ferruginous arkosic sandstones. In Southern Mozambique, the late-Miocene and Pliocene epochs are characterized by an uplift of the continent. The periods of Pliocene and subsequent Quaternary sea-level drop and coastline regression have resulted in erosion of the uplifted inland areas and, consequently, in the sedimentation of the eroded material in downstream alluvial flood plains. The resulting Pliocene and Quaternary alluvial deposits have in places been transported over long distances.

The Pliocene continental alluvial formations are unnamed (Table 7.2) and presumably little known. The Pleistocene deposits are heterogeneous, consisting of a deltaic and lacustrine sequence of clays, sands and interbedded sandstones and calcarenites. These heterogeneous deposits are the result of a complex sequence of processes, involving sedimentation during sea-level rises and coastline transgression, and erosion, wind and river action during sea-level falls and coastline regression. Three major transgressions have occurred in the area, during which the marine and lacustrine Macia, Gondza and Inhaca Formations were respectively deposited. Lower Pleistocene fine sands and clays (generally a few tens of meters thick) separate the Macia Formation from the underlying Tertiary deposits. During one of these transgressions the sea inundated the depression around the Chokwé area, extending up the Limpopo flood-plain and across a low divide between the lower Limpopo and Inkomati drainages. Groundwater quality is influenced by this history of fluctuating sea levels. Some areas protected by Macia palaeodunes escaped inundation. From the inspection of Landsat 7 satellite imagery, it appears that a former sea-level transgression flooded a tectonically controlled valley leading down from the town of Funhalouro and connecting this palaeo-drainage to the current drainage basin of the Inharrime River.



8. HYDROGEOLOGY 8.1 Concept of hydrogeological regions The hydrogeology of large geologically complex areas such as the Limpopo Basin, is best described in terms of hydrogeological regions with more or less uniform groundwater occurrence characteristics. The western and central sections of the Limpopo River Basin are underlain by geological formations predominantly of Proterozoic and Archaean age. Formations of Palaeozoic / Mesozoic age (for example the Karoo Supergroup) occur across the basin and are of importance due to their different geohydrological characteristics and potential for groundwater exploitation. In the extreme western and eastern areas of the basin (Kalahari and coastal plain respectively) younger formations (Cretaceous and Quaternary age) occur. Fundamental to groundwater hydrology is the way in which water is stored and moves in geological formations. This is controlled by the nature of the interstices, their origin, shape and interconnection that form the receptacles and conduits for groundwater. Vegter (2000) classified the interstices in two groups: primary and secondary openings and used this as a basis for his classification of geohydrological regions in South Africa and in the production of hydrogeological maps for the country. From the hydrogeological maps prepared for the other three countries in the Limpopo Basin, it is evident that this approach is equally well applicable to the hydrogeology of the entire Limpopo Basin. For the purpose of this report a hydrogeological regions classification approach was adopted but with a less detailed subdivision than that proposed by Vegter (2001). As mentioned in the previous section, the Limpopo basin (especially in Botswana, South Africa and Zimbabwe) is predominantly underlain by rocks representing Precambriam geology, of which the hydrogeology is often referred to as “hard rock hydrogeology”. On the other hand, the portion of the Limpopo Basin in Mozambique is hydrogeologically dominated by unconsolidated and semi-consolidated deposits hosting mainly primary unconfined aquifers. In addition substantial and strategically important groundwater resources are associated with the many sediments in the ephemeral streams and river courses in all four of the countries. Of these the Limpopo River is a classical example and the most important from a groundwater perspective. The current classification of groundwater regions into geohydrological units or regions differs between the four countries. The primary classification into three Classes (A, B and C) for Mozambique is based on the dominant porosity type, the extent of the aquifers and aquifer yields. Each Class was then further subdivided into three units principally based on yield prospects, coupled to geological and morphological characteristics. In this way the classification consists of three Classes, nine Groups and 32 hydrogeological Units (Ferro and Bouman, 1987). All three classes are represented in the Limpopo Basin in Mozambique. In delineating the regions in South Africa, Vegter (2001) used a combination of lithostratigraphy, physiography and climate, and not one based on primary or secondary water-bearing openings as was the case in for example Mozambique. Using this approach Vegter has identified 18 different hydrogeological regions in the South African part of the Limpopo Basin. In producing the National Groundwater Maps for Botswana (1987) and Zimbabwe (1985), a lithologically based classification system (10 units) was used and in the case of Botswana, this was also linked to water potential classification criteria (5 classes). The five main lithological groupings are

1) Archaean basement rocks (granites, gneisses, greenstone belts, volcanics); 2) Sedimentary units of Proterozoic age (i.e. Transvaal basin and Waterberg Group with

shales, quartzites, dolomite, conglomerate and associated volcanic sequences)),



3) Palaeozoic/Mesozoic age Karoo Supergroup sedimentary deposits with associated intrusions (i.e. dyke and basalt flows);

4) Cretaceous and younger age consolidated and unconsolidated sedimentary sequences mainly in Mozambique; and

5) Recent deposits associated with water courses such as the Limpopo and Shashe Rivers.

8.2 Brief description of the hydrogeology of the four countries In this section only a brief description of the major geohydrological characteristics in each of the four countries is presented. 8.2.1 Botswana The Limpopo Basin in Botswana is characterised by 4 major geologic units: Achaean basement and gneisses, Proterozoic sedimentary units (i.e. Waterberg Group), the Karoo Supergroup and Karoo age dykes and intrusions (i.e. dyke swarm). A minor but important occurrence of dolomite is present in the very upper reaches of the basin along the border with South Africa near Ramotswa. In the basin, the most extensive geologic formation is the Achaean basement and gneisses which underlay the northeastern half of the basin in Botswana as well as extensive areas in the upper basin around Gaborone. The second most extensive unit is the Karoo Supergroup, followed by the Proterozoic sedimentary formations. Groundwater resources in the Limpopo Basin of Botswana have generally been sufficient for rural water supply. However, poor groundwater potential in many of the basement aquifers (i.e. Northeast District) reflected in low yields and aquifer depletion has often created difficult supply problems for larger villages. Fractured-porous aquifers in the basin, such as Karoo and Waterberg sandstone units, also generally have good groundwater potential that is being utilised in some existing wellfields (i.e. Serowe, Palla Road, Molepolole). In particular, potential of the Ntane Sandstone Formation (Lebung Group, Karoo Supergroup) is generally quite good and characterised by high yields and good quality. Both Serowe and Palla Road Wellfields are developed in the Ntane Sandstone aquifer, and very high yields (100-150 m3/hr) and good quality. Well fields such as Palla Road and Khurutshe, form an important example of groundwater utilisation to provide backup to surface water sources during drought periods. One area of under-utilised potential is The alluvial aquifers along the Limpopo River are currently under-utilised and have the potential for high yields, whereas those aquifers along Limpopo tributaries generally have much lower potential due to limited aquifer extent and less than optimum hydraulic characteristics. 8.2.2 Mozambique Due to the different geological conditions in the Limpopo Basin in Mozambique, the hydrogeology of the basin differs totally from that of the other three countries. This is due to the difference in geology. The Lebombo rhyolite along the border between South Africa and Mozambique, represent the only real “hard rock” aquifer, whereas in the other countries these aquifers are the dominant group. The aquifers in rhyolite and basalt are of the weathered and fractured type. Yields are relatively higher in basaltic units than the rhyolitic units. While water quality in basalt is generally of an acceptable quality, the water found in the rhyolite is usually of a better quality.



To the east of the rhyolite outcrops, post-Karoo Cretaceous and younger sediments are present. Formations of the Upper Cretaceous include very thick lithologically monotonous sections, such as the Sena Formation. It consists of sandstones and conglomerates with clayey cement, both practically impermeable. Groundwater in this formation has a high TDS. Tertiary formations occur south of the Save River and crop out only along the course of some rivers. A thin alluvial sandy clay or clayey sand cover commonly masks these formations which consist essentially of calcareous sandstone and clayey calcareous sandstone. These formations have variable water bearing characteristics. The Palaeocene and Eocene formations represent marine facies with sandstone and conglomerate lithologies predominating. Groundwater from these sources is generally saline. The Quaternary dune formations and alluvium occur generally along the coast and represent the only fresh water source. The dune formations consist of fine to very fine sands. Generally, the average yield of aquifers in these units is 3 to 10 m3/h. Alluvial formations of significant extent also occur primarily along the lower reaches of the Limpopo River. 8.2.3 South Africa As is the case in Zimbabwe, the groundwater in the South African part of the Limpopo Basin occurs predominantly in secondary aquifers developed in the rocks of Achaean, Proterozoic and Palaeozoic/Mesozoic ages. In addition to the Limpopo River, there are numerous ephemeral river systems that drain into the Limpopo River with well-developed and important alluvial aquifers. Examples are the Crocodile, Olifants, Sand and Mogalakwena Rivers. In terms of strategic groundwater resources, the dolomitic aquifers of the southern part of the basin (around Pretoria, West Rand and towards the Botswana border) are the most important aquifers in the basin. The local importance of the dolomite aquifers for irrigation and domestic water supply, is illustrated by the fact that the dolomite aquifers in the Upper Molopo area north of Lichtenburg was proclaimed in 1966 as a Subterranean Government Water Control Area (Stephens and Bredenkamp, 2002). When in 1983 the drought and water shortage in the Vaal River catchment assumed serious proportions, an extensive investigation into the possible temporary mining of groundwater from the dolomites for use as emergency water supply for the region was started. It is estimated that the some 10 000 million m3 is held in storage in the dolomite aquifers and that it is replenished at a rate of 270 million m3 per annum (Vegter, 1988). Apart from the large volumes of water abstracted from these aquifers for agriculture and domestic (rural and towns) use, the gold mines on the West Rand have in the past abstracted enormous volumes of water from these aquifers in order to create safe mining condition in the gold-bearing Witwatersrand rocks underlying the dolomite of the Chuniespoort Group. This still continuous, however, at a much reduced scale due to the closure of many of the mines in the Greater Johannesburg area. Barnard (2000) mentions that more than 50% of the water supply boreholes in the dolomite have a recorded yield of >5 l/s, with a maximum recorded yield of 126l/s. In general the groundwater potential from aquifers in the weathered and fractured basement rocks is low. There are, however, exceptions, such as the area around Dendron where exceptionally large volumes of groundwater are abstracted for irrigation purposes. On the other hand, the basement granite of the Makoppa Dome area along the Botswana border in the southwestern part of the basin and where similar geological conditions exist, is poorly endowed with groundwater (Vegter, 2000). Isolated occurrences, in areas generally regarded to have a low groundwater potential, of boreholes with high yields do, however, occur. Examples of isolated high yielding boreholes, such as the Nebo Granites (Botha et al, 2001), Limpopo Mobile Belt (Sami et al, 2002), Karoo sandstones (Zwarts, 1987; Fayazi and Orpen, 1989; Du Toit and Haupt, 1995; Verhagen et al, 2000), can be found in many parts of the basin.



Four sedimentary basins of Karoo age (Palaeozoic/Mesozoic) occur in the South African part of the Limpopo Basin. These are the Springbok Flats basin, the Tshipise basin, the Ellisras basin and an extension of the Zimbabwean/Botswana Tuli basin (Bordy and Catuneanu, 2002). In terms of groundwater importance, the Springbok Flats and the Tshipise basins are the most important and best known. The sandstone aquifers of the Springbok Flats support large scale irrigation schemes, whereas at the western edge of the Tshipise basin, the groundwater occurrence is the subject of extensive research projects while also supplying parts of the domestic water needs of the region, for example to Ellisras (Fayazi and Orpen, 1989: Verhagen et al, 2000). The water saturated alluvium forming the primary aquifers associated with some of the larger rivers in the basin, for example the Limpopo, Olifants, Sand, Mogul and the Crocodile rivers, are important for local farming, mining and domestic water supply (Orpen and Fayazi, 1984; Orpen and van Rensburg, 1990; Hobbs and Parsons, 1986; Hobbs and Chips, 1986; Hobbs et al, 1987; De Klerk and Wiegmans, 1990; Bredenkamp, 1995; Hobbs and Venables, 1986; Bredenkamp et al, 1986). The towns of Mussina, Potgietersrus and Thabazimbe for example obtain most of their water needs from these aquifers, the Venetia diamond Mine southwest of Mussina gets a large proportion of its water needs from the alluvial aquifers of the Limpopo River, and large scale irrigation based farming is practiced along extensive sections of the Limpopo River, notably in the vicinity of Pontdrif. 8.2.4 Zimbabwe Across the border in Zimbabwe, >70% of the surface area of the Limpopo Basin is underlain by Archaean granite and gneiss. In the southeastern part of the basin sandstone and basalt of Karoo age occur. An extensive review of the hydrogeology of Zimbabwe is contained in the National Water Master Plan for Rural Water Supply and Sanitation (1985). In this report, the aquifers of the country are divided into 10 major hydrogeologic units, with one of the units (the Karoo) further sub-divided into 5 sub-units. However, only three main features are described here that apply to the southern parts of Zimbabwe. The Archaean granite and gneiss of the Basement and Limpopo Mobile Belt represent the main rock types in the Limpopo basin. In these groundwater occurs in the shallow weathered zone and in deeper fractured zones. Although high yields are occasionally encountered, in general the yields are low (10-50 m3/d). Water quality is generally good, but many of the smaller weathering basins are vulnerable in terms of overexploitation due to limited storage volumes. Two sedimentary basins of Karoo age and covered by late Karoo basalt, are prominent features in the southwestern and southeastern part of the basin. The western basin, known as the Tuli Basin (Bordy and Catuneanu, 2002) extends into Botswana and South Africa. The eastern basin is referred to as the Nuanetsi Basin and is connected to two other Karoo basins, the Tshipise Basin in South Africa and the Save Basin further north in Zimbabwe. In all cases the Forest sandstone underlies the basalt, and it has been proven in Botswana and South Africa that this formation can be a significant fractured and confined aquifer. It has however, not been extensively exploited in the southern part of Zimbabwe. The Zimbabwe Regional Hydrogeological Map (1986) reports yields of 50-300 m3/d with a good water quality. Where covered by basalt, these aquifers usually occur at great depth and are laterally extensive. In the extreme eastern part of the Limpopo basin (east of the Nuanetsi Basin) and along the border with Mozambique, the basalt is overlain by mainly mudstones of Cretaceous age. These do not constitute a good aquifer as yields are generally very low and the water is brackish to saline. The underlying Karoo basalt and sandstone have not been explored for its groundwater potential. Some important and significant aquifers are associated with the alluvial deposits associated with the major rivers such as the Limpopo, Shashe, Masunga and Naunetsi. Two of these, the Limpopo and Shashe Rivers, form the borders with South Africa and Botswana and therefore should be classified as transboundary or international aquifers.



8.3 Hydrogeological region classification for the Limpopo Basin In defining geohydrological regions for the Limpopo Basin, geological characteristics played a dominant role. For describing the hydrogeological characteristics of the groundwater regions a number of different approaches have been followed. These are all essentially based on the concept of “Groundwater occurrence” which plays a dominant role, and linked to an “aquifer type” classification. Groundwater occurrence is described in the different countries with terms such as “Principle groundwater occurrence”, “Borehole yield class”, “Average transmitting properties”, “Groundwater development potential classification”, and “Productive aquifers” in contrast to ”Areas with limited or no groundwater”, while aquifer type is generally described by terminology such as “Intergranular”, “Fractured”, “Intergranular and fractured” and “Karst”. The basin has been divided into the eight regions based primarily on the simplified geological map shown in Figure 8.1. These eight regions are shown in Figure 8.1 and briefly summarised in Table 8.1. A description of each region is given below. In this report a system where the geohydrological character of the water bearing rocks are classified into the four aquifer types mentioned above is used: Intergranular, Fractured, Intergranular and fractured, and Karst. 8.3.1 Unit L0: Alluvium associated with river courses The alluvium filled channels associated with the Limpopo River and its major tributaries forms a large, high yielding, sustainable aquifer that occurs over a distance of more than 2 250 km (Boroto and Görgens, 1999). Some sections of this aquifer are shared by two countries (for example sections of the Shashe River between Botswana and Zimbabwe, the Olifants (Elefantes) River in South Africa and Mozambique), while others are totally within one country (i.e. Crocodile River in South Africa). These types of aquifers are extensively developed within all four countries and can play a major role in water supply during (surface water or meteorological) drought periods. Information provided in the report by Boroto and Görgens (p. 21-22) gives an indication of the surface water channel dimensions. This information has been used to make a conservative assessment of the amount of alluvium associated with the river course and that can be utilized for groundwater storage. For this purpose the catchment is divided into river reaches as described earlier, and the groundwater storage capacity has been estimated according to these reaches. This information is captured in Table 8.2.

• River reach 1: Portion of the Upper Limpopo River Main Stem from just upstream of the confluence of the Crocodile and Marico Rivers in South Africa, to the flow gauging station at Sterkloop.

• River reach 2: From the Sterkloop flow gauging station to the confluence with the Shashe.

• River reach 3: From the Shashe confluence to Beit Bridge. • River reach 4: from Beit Bridge to Pafuri • River reach 5: From Pafuri to Chonkwe

Areas of known large water abstraction from this resource amount to 114 x 106 m3/a (only SA) Upstream of confluence between Limpopo and the Olifants River in Mozambique, the alluvial system is narrow but well developed. To the south of Chokwe the alluvial deposits constitutes a stratified layer, together with deltaic sediments. The depression at Chokwe was caused by transgressions during the Quaternary, resulting in marine deposits and eventually saline groundwater conditions.



Figure 8.1: Simplified geological map of the Limpopo basin

Figure 8.2: Hydrolithological units within the Limpopo Basin.


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Table 8.1: Representation of Geohydrological Regions or Units in the Limpopo Basin

Unit #

Unit/Region lithological description

Primary / Secondary

Main geological formations represented

Brief description and principle water bearing rocks

Country representation

L0 Alluvium Primary Alluvium associated with river courses Botswana, S. Africa, Zimbabwe, Mozamb.

L1 Fractured Basement Complex

Secondary Makoppa Dome and equivalent in Botswana

Granite Botswana, South Africa

L2

Fractured Felsic and mafic rocks, sedimentary successions; isolated Karoo basins, Basement granite

Primary and Secondary

Bushveld Complex; Transvaal Sequence; Karoo volcanics and sandstone; Halfway House granite

Felsic and mafic sequence of Bushveld Complex; sedimentary sequence of quartzite, shale, andesite, dolomite including karst conditions in places; granite

Botswana, South Africa

L3

Fractured sedimentary successions overlying fractured Archaean basement

Secondary Palapye, Waterberg, Soutpansberg, Archaean basement

Quartzites, conglomerates, sandstone, shale, granite Botswana., South Africa

L4

Fractured meta-sedimentary successions and gneiss

Secondary Northern Limpopo Mobile Belt

Gneiss, metasediments South Africa, Botswana, Zimbabwe

L5 Fractured basement rocks

Secondary Zimbabwean Craton (Archaean)

Granite, Gneiss Botswana, South Africa

L6

Weathered fractured (felsic) basement complexes

Secondary Limpopo Mobile Belt; Archaean Basement Complex

Granite and Gneiss (Limpopo Mobile Belt), Basement Complex Granite Botswana, Zimbabwe

L7

Unconsolidated sand and coastal sands; Fractured sedimentary

Primary and secondary

Elefantes and Mazamba Fms; Sena Fm

Aeolian, medium to coarse cover sands in the western part of the basin; unconsolidated to semi consolidated aeolian and shallow marine deposits in the lower reaches of the Limpopo River in Mozambique Thick Cretaceous succession of shallow marine deposits, dominated by shale and glauconitic sandstone, usually saline groundwater conditions

Predominantly Mozambique, small section in Zimbabwe

Limpopo Basin Groundwater Situation Analysis – Final Report

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Table 8.2: Groundwater storage in alluvium associated with the Limpopo River and its main tributaries.

River reach Channel bed storage

(x 106 m3) Bank/Riparian Zone storage (x 106 m3)

Total storage (x 106 m3)

1 44.4 93.2 137.6

2 34.7 104.6 139.4

3 70.8 177.2 248.1 4 60.0 56.6 116.5

5 69.8 116.5 186.6 Total 828.2

Generally the alluvial system associated with the Limpopo River in Mozambique is dominated by clay rich deposits intercalated with coarse to very coarse alluvial sands and good water quality and yields. In contrast, the Changane alluvial system is very limited in depth and extension and also very clayey, with a generally poor water quality. The Changane valley system drains the adjacent brackish aquifer system, especially along the area situated below the confluence of the Limpopo and Olifants rivers. Fresh water being recharged from the river is found occasionally in these areas. The Limpopo alluvial system in Mozambique is characterized as clayey intercalated by sands, occasionally with limestones. This feature occurs more towards Pafuri as well as along the Changane River valley. From the Limpopo mouth upstream to the Chilembene area near Chokwe the Limpopo valley aquifer system contains brackish water while the Changane River valley system contains some fresh water groundwater on a deeper brackish system from Chilembene towards Estivane. Groundwater potential of the old alluvial plains near the coast of Mozambique is very limited. Further inland in the areas adjacent to Limpopo Olifants confluence, in South-North direction (Estivane), these aquifers associated with old alluvial plains are well developed. These are characterized by calcareous sandstones and limestones. The eroded valleys overlying the Tertiary and Cretaceous sedimentary formations have very limited thickness of alluvial materials and do not constitute a significant aquifer. 8.3.2 Unit L1: Fractured Basement Complex granites This region is characterised by basement Complex granite and straddles the South African Botswana border. Borehole yields are very low, and water strikes are generally deep. Water quality is generally below 2 000 mg/l and the water level is >50 m (South African side). 8.3.3 Unit L2: Fractured Transvaal sequence and Bushveld Complex This Unit comprises of the Transvaal predominantly sedimentary sequence, the Bushveld Complex and some smaller outcrops of Karoo volcanics and sediments. Of the Transvaal Sequence the dolomites are the best aquifers and where karst conditions have developed in these, exceptionally high yields (>50 l/s) can be attained and sustained. Groundwater conditions in the rest of the Transvaal Sequence are generally low, and controlled by the fractured nature of the rocks. Where the mafic succession of the Bushveld Complex is deeply weathered, high yield have been reported. The felsic sequence (Nebo Granite) is also a low yielding formation, although extensive geophysical exploration and deep drilling has revealed the presence of some high yielding structures. These have been confirmed through drilling. Karoo basins (volcanics overlying fractured sediments) within this unit are good aquifers and provide scope for large-scale irrigation.



8.3.4 Unit L3: Fractured Waterberg, Palapye, Soutpansberg groups This Unit is mainly represented by the sedimentary successions of the Waterberg, Soutpansberg and Palapye groups. They do not possess any primary porosity and groundwater occurrences are controlled by geological structures. In general groundwater yields are low, although there may be scope in exploring the fractured basement rocks underlying the se groups. 8.3.5 Unit L4: Central Zone of the Limpopo Mobile Belt This unit comprises mainly of the granite and gneissic rocks of the Cental and Northern Marginal Zones of the Limpopo Mobile Belt. Unless associated with major geological structures, the groundwater conditions in the granite and gneiss are generally poor. A number of Karoo age sedimentary basins overlain by volcanic sequences occur in this unit. 8.3.6 Unit L5: Zimbabwean craton This unit is located on the granites and gneisses of the Zimbabwean craton. Groundwater is associated with shallow weathered basins and fracturing. Yields are generally low. 8.3.7 Unit L6: Kaapvaal craton This unit consists of mainly gneissic rocks of the Kaapvaal Craton and the Southern Marginal Zone of the Limpopo Mobile Belt. In the central part of the unit some Archaean greenstone belts are present. 8.3.8 Unit L7: Unconsolidated sand and coastal plain aquifers This unit basically represents the Kalahari group deposits in Botswana and includes the coastal sands of Mozambique. The Kalahari sands within the Limpopo catchment are not recognized as a significant aquifer and will not be dealt with in detail in this report. Along the Mozambique coast a system of Recent dunes composed of medium size sands without clay is present. An older dune system up to 100 km wide in places, is found along the coastal strip and was formed during the interfluvial periods in the Pleistocene Glacial period and occasionally reaches up to 100 m in thickness, especially to the south of Gaza and Inhambane Provinces. These dunes are composed of fine to medium grained sands and cover extensive palaeovalleys in the lower reaches of the Limpopo and Changane Rivers. The rate of recharge of this system is rather high, while the water levels follow more or less the topographic or gradient of the surface. Some artesian conditions have been identified along the limits of the dunes valley. A deeper regional confined aquifer (Bouman, 1985a) consisting of semi-consolidated continental deposits of Pliocene age is well developed over large areas of the coastal plain. Confirmed occurrences are at Mabalane (80 m deep) and Xai-Xai (200 m), but he lateral extent has not been established. These deposits are thought to be geologically equivalent to the Mazamba formation outcropping at Inhambane. 8.4 Groundwater Potential and Resources 8.4.1 Botswana Groundwater sources in the Limpopo Basin of Botswana have generally been sufficient for rural water supply. However, poor groundwater potential in many of the basement aquifers (i.e. Northeast District) reflected in low yields and aquifer depletion has often created difficult supply problems for larger villages. One area of under-utilised potential is alluvial aquifers



along the Limpopo River, where sediment thickness and lateral extent are large and average yields are quite high. Alluvial aquifers along Limpopo tributaries generally have much lower potential due to limited aquifer extent and less than optimum hydraulic characteristics (see for example BGS, 1998). Fractured-porous aquifers in the basin, such as Karoo and Waterberg sandstone units, also generally have good groundwater potential that is being utilised in some existing wellfields (i.e. Serowe, Palla Road, Molepolole). In particular, potential of the Ntane Sandstone Formation (Lebung Group, Karoo Supergroup) is generally quite good and characterised by high yields and good quality. Both Serowe and Palla Road Wellfields are developed in the Ntane Sandstone aquifer, and very high yields (100-150 m3/hr) and good quality are encountered in the Ntane Sandstone aquifer near Bobonong. The above-mentioned North-South Carrier pipeline includes a major wellfield, Palla Road/ Khurutshe, which can back up supply in the case of reduced surface water storage. The wellfield is located in Karoo sandstones and total average recharge was estimated at 11 800 m3/day. Numerical modelling has been used to evaluate the total emergency yield that could be provided by the wellfield. For back up interval of five years, the aquifers are estimated to be capable of producing up to 33 290 m3/day. These wellfields form an important example of groundwater utilisation to provide backup to surface water sources during extended periods of drought. 8.4.2 Mozambique Alluvial valleys associated with river courses form important shallow primary aquifers in Mozambique. Development of these water sources is however risky due to flood conditions often experienced in the Limpopo River flood plain. Those along the middle reaches of the Limpopo are especially important due to the good quality of the water and high specific yields of up to 20 m3/h/m. However, DNA (1985) caution that these resources should not be overestimated, as over-utilization could lead to salinisation of the aquifer. This is especially applicable to the lower reaches of the Limpopo due to marine inundations during geological times or sea water intrusion near the river mouth. 8.4.2.1 Dune aquifer system The system is found along the coastal strip where the primary aquifers are associated with young dune deposits. Older dune systems occur up to 100 km inland and often overly old erosional valleys. The old dune systems where deposited during interpluvial periods in the Pleistocene Glacial period and can reach thicknesses of up to 100 metres in the south of Gaza and Inhambane Provinces. The more recent coastal dunes are composed of medium size sands without clay. The rate of recharge of this system is rather high, while the water levels follow more or less the topographic or gradient of the surface. Some artesian conditions have been identified along the limits of the dunes valley. Aquifer productivity varies from low to medium, with recorded specific yields within a range of 0.1 to 1.5 m3/h/m while permeabilities vary between 1 and 5 m/d (Bouman, 1985). Ground water potential as estimated in the Lower Limpopo (Bouman, 1985) indicates productivities of about 5 to 10 m3/h for an area of 1 km2 and an average borehole depth of 75 meters. The hydrogeological map of Mozambique shows a dune aquifer system along the coast of low to moderate productivity (3 to 10 m3/h). The formation consists of coarse to medium aeolian sands. The dune belt is not present near the estuary of the Limpopo at Xai-Xai. Further inland (east) the aquifer productivity reduces to less than 5 m3/h. These aquifers are composed of fine loose sands sometimes with clay, overlying the sedimentary rocks. Alternating sequences deposited by under aeolian and marine transgression periods are



often present. Despite the marine depositional history, groundwater quality in these formations is found to be generally good with less than 500 mg/l salt content. In the low lying areas around Chokwe, groundwater is however found to be brackish. According to Bouman this aquifer system offers good conditions for groundwater exploitation with moderated permeabilities and good water quality owing to good recharge rate and groundwater circulation. 8.4.2.2 Alto Limpopo plains The groundwater potential in the northeastern part of Limpopo Basin in Mozambique (also referred to as the Alto Limpopo Plains) dominated by the arkosic sandstones of the Cretaceous Sena and Lower Tertiary Elefantes Formations, is low. The main water bearing strata are conglomerates and calcareous facies in these formations where occasional yields of up to approximately 1 l/s have been recorded. Water quality is reasonable (around 1 000 mg/l), but poor recharge conditions and deep water levels generally restrict the development of this limited resource. A failure rate of 40% has been reported for these formations (Ferro and Bouman, 1987). The groundwater potential of the younger Miocene age Mazamba Formation underlying the Alto Changane Plains and comprising of arkosic and argillaceous sandstones, is moderate to low. In the area between the Changane and Limpopo Rivers the sandstone has a higher clay content which impacts negatively on borehole yields. In addition, the water quality is poor with TDS values generally in excess of 3 000 mg/l reaching in places 30 000 mg/l. The quaternary cover on the Mazamba Formation is in places up to 60 m thick, but water quality is brackish to saline. A potentially higher yielding aquifer containing relatively fresh water (800 – 1 200 mg/l) is present at a depth of between 50 m (along the Limpopo and Changane valleys) and 200 m. This aquifer is referred to as the “Limpopo aquifer” and in the area to the north of the Limpopo River, the estimated renewable groundwater resources are estimated to be approximately 3 x106 m3/a (Ferro and Bouman, 1987). Permeabilities are low and range between 0.8 and 1.4 m/d. Groundwater conditions in the basalts and rhyolite of the Lebombo volcanic rocks are not favourable for the development of high yielding boreholes. In general the basalts are more productive than the rhyolite, but yields are still low. Groundwater quality of the rhyolite is better than that of the basalt and TDS is usually below 500 mg/l. Groundwater in the plains along the Lebombo mountain range is of poor quality, borehole yields are in generally low and the groundwater development potential is regarded to be low due to the poor quality of the groundwater and low recharge. 8.4.2.3 Deep aquifer system Several authors have suggested the existence of a regional aquifer in the Limpopo valley (Bouman, 1985a). A deep aquifer system was eventually discovered during the geophysical prospecting in the Catchment as part of rural development plan for cattle farming. The top of this aquifer is at 80 meters depth in Mabalane, whereas at Xai-Xai it occurs more than 200 meters below surface. This aquifer consists of semi-consolidated continental sediments of Pliocene age corresponding to the Mazamba formation outcropping in Inhambane to the East of Changane River. Average yield of this formation is 0.8 m3/h/m, decreases towards the coast to 0.2 m3/h/m beneath the dunes. One deep well in Chokwe which was drilled into this formation, had a moderate yield of 5 m3/h/m. This deep aquifer is confined and the piezometric water levels increase towards the east, suggesting a west to east regional flow direction. Water quality of this system is known to be moderate to good with mineralization less than 1 000 mg/l occasionally higher to 2 500 mg/l. This system seems to be limited on top by brackish system as well as its surroundings.



Three aquifers with moderate yields are found in the interfluvial plain between the Limpopo and Incomati Rivers. These are developed in the Palmeira Limpopo graven to the south of the Limpopo River. Although moderate yielding boreholes are developed in the upper aquifer, it contains saline water, and because of the hydraulic connection to the lower, better quality deep aquifer (80 m to 180 m), the development potential of the deeper aquifer is negatively impacted upon. The lower of the three aquifers is confined as a result of the presence of an up to 60 m thick clay layer isolating it from the upper more saline water aquifers. This aquifer occurs at a depth of between 180 m and 300 m. Average permeability of this aquifer is 2.4 m/d and average TDS value is around 1 000 mg/l. Available renewable groundwater resources have been calculated by Ferro and Bouman (1987) to be 3.5 x 106 m3/a. 8.4.3 South Africa Approximately 10 years ago the South African Department of Water Affairs embarked on a systematic collection of groundwater information. A National Groundwater Database (NGDB) was created in which all hydrogeological information is stored. This database forms the core of a long term Water Research Commission project where descriptions of all major groundwater regions in South Africa are compiled. The first three brochures, two of which cover specific hydrogeological regions, have been published to date. This database further forms the basis for the Governments water supply programme to the rural communities. In the Limpopo Province a separate database is being developed with the assistance of several groundwater consultants. This database is referred to as GRIP (Groundwater Resource Information Programme). This database, despite being in the early stages of development and population, has already proven to be an extremely valuable tool for the development of the groundwater resources in the Limpopo Province. . The Directorate Water Services has initiated a programme of “Groundwater Developing Strategies”. In the Limpopo Province these strategies are developed on a District Municipality basis and the first of these are currently under development. In the follow-up phases of this SADC project, as well as the larger GEF project, these documents will provide an invaluable source of information for future groundwater development strategies. The databases referred to above, have assisted the Department in compiling statistics on groundwater for all major catchments. Table 8.3 below provides a summary of the ground water resources in the Limpopo Basin in South Africa on a primary and secondary catchment level. A borehole density map for South Africa, Botswana and Mozambique was compiled based on information gathered during the country visits (Figure 8.3). This map indicates large areas in South Africa where more than 2.5 boreholes per square kilometre are present. This is in part a reflection of the low yielding nature of the aquifers, as well as population density. This map, read in conjunction with other maps, for example, recharge potential maps, groundwater consumption maps, groundwater dependent population density maps, Groundwater Dependent Ecosystem (GDE) maps and others, will be useful in the development of groundwater management strategies. 8.4.4 Zimbabwe Approximately 80% of the Limpopo Basin in Zimbabwe is underlain by Archaean igneous and metamorphic bedrock, primarily granites, gneisses, metavolcanics and metasediments. The rest is divided between Karoo age basalt and sedimentary successions (~15%) and Cretaceous sediments (~5%). Within the Limpopo Basin the Karoo is predominantly represented by the Clarens or Forest sandstone and the Stormberg basalt groups. In the



southwestern part of the basin, unconsolidated sands and clays of the Kalahari Beds often occur as a thick cover. Several small and elongated but significant areas of alluvium, i.e. associated with the Limpopo, Shashe, Umzingwazi and Mwenezi Rivers are also present which support large groundwater resources. Table 8.3: Surface and groundwater resources and utilization in the Limpopo Basin, South Africa (in

million m3/a)

Catchment Subcatchment Surface water

Groundwater Irrigation Urban Mining and Bulk

Total yield

Apies/Pienaar 37 24 4 109 2 176

Upper Crocodile 111 31 21 166 14 343

Elands 30 6 3 10 14 63

Lower Crocodile 7 29 14 2 8 60

Marico 14 12 2 3 1 32

Upper Molopo 3 9 0 5 2 19

Crocodile West/Marico

Subtotal 202 111 44 295 41 693

Matlabas/Mokolo 35 7 3 1 0 46

Lephalala 38 4 0 0 0 42

Mogalakwene 50 15 3 4 0 72

Sand 10 71 0 11 0 92

Nzhelele/ Nwanedsi 27 1 2 0 0 30

Limpopo

Subtotal 160 98 8 16 0 282

Luvhuvu/Mutale 88 20 5 2 0 115

Shingwedzi 1 2 0 0 0 3

Groot Letaba 133 13 13 1 0 160

Klein Letaba 21 9 1 1 0 32

Lower Letaba 0 0 0 0 0 0

Luvuvhu/ Letaba

Subtotal 243 44 19 4 0 310

Upper Olifants 194 4 2 37 4 241

Middle Olifants 99 70 34 5 1 209

Steelpoort 42 14 3 1 1 61

Lower Olifants 74 11 5 2 8 100

Olifants

Subtotal 409 99 44 45 14 611

TOTAL 1 014 352 115 360 55 1 896

Groundwater occurrence in the basement rocks is controlled by secondary porosity associated with fracturing, jointing and weathering. Average depth of weathering is of the order of 10 m to 30 m. Borehole yields from the weathered and/or fractured zones of the Archaean granitic and gneissic are generally low (10-50 m3/d) with specific capacity between 2 and 20 m3/d/m. Where weathering is well-developed yields of 50 to 100 m3/d are possible. Water levels are usually less than 10 mbgl and quality is generally good.



Relative small outcrop areas of metasediments and felsic and acid metavolcanics of the Bulawayan and Shamvaian Groups are present to the south and southeast of Bulawayo and around Gwanda. These are, though small, important aquifers in the Basin. The Bulawayan Group is characterised by laterally extensive aquifers with yields of 100-250 m3/d while the Shamvaian Group has less potential with limited aquifer development and yields of the order of 10-25 m3/d. Groundwater quality in both groups is good.

Figure 8.3: Borehole density map for Botswana, Mozambique and South Africa.

The hydrogeological unit representing the Karoo age formations (Unit 6), is only represented in outcrop by one of the sub-units identified on the hydrogeological map. This is Unit 6a which represents the upper formation of the Karoo, the Batoka Basalt. Large outcrops of this formation are present in the south and southeast of the basin. This is underlain by Unit 6b which represents the Forest sandstone formation (the geological equivalent to the Clarens (South Africa) and the Ntane sandstone formations (Botswana). In the Batoka basalt formation groundwater occurs both in weathered and/or fractured zones with yields of 20-100 m3/d. Water quality is generally good. The confined aquifer underlying the basalt is laterally extensive and has both primary as well as secondary porosity. Despite the estimated low primary porosity of <3% for the Forest sandstone, (based on experience from the South African equivalent Clarens sandstone aquifer), the aquifer has a huge groundwater potential because of its large storage. According to the hydrogeological map of Zimbabwe, yields of 50-300 m3/d are possible and water quality is good. Conservative calculations of storage, based on basalt outcrop area, a primary porosity of 2% and an aquifer thickness of 50 m, indicate that approximately 5 x 109 m3 of groundwater is potentially stored in this aquifer to the northwest of Beit Bridge. Recharge studies done by Larsen et al, (2002) at the Nyamandhlvu aquifer to the northwest of Bulawayo, and Bredenkamp et al, (1995) from studies on Letaba Basalt on the Springbok Flats area north of Pretoria in South Africa, produced recharge estimates of between 10 mm and 25 mm/a and 2.8% of mean annual rainfall (approximately 17 mm/a) respectively. Using a conservative estimate of 10 mm/a



recharge based on the studies by these authors, hydrogeological conditions (Larsen et al, 2002) and recharge (Bredenkamp et al, 1995), recharge is estimated to be only about 100x106 m3. Therefore, should this aquifer be exploited to any large degree, groundwater management will be of utmost importance.

Figure 8.4: Groundwater quality expressed as EC (mS/m) across the Limpopo basin. Mudstones, siltstones and sandstones representing the Cretaceous formations (Unit 7 of the hydrogeological map of Zimbabwe) are present along the southeastern area of the basin in Zimbabwe. Limited data are available but average yields are of the order of 10-50 m3/d. Water quality is variable and similar to the conditions found across the border in Mozambique, TDS values are generally high. The aquifers associated with alluvial deposits which are locally well developed in limited areas along the river courses of the major rivers draining the basin, are of great importance. Lithologies are highly variable, but where clean sands are present and units are thick, such as at selected sections along the left bank of the Limpopo River, groundwater potential is high. Yields in these areas are in the range of 100-5 000 m3/d. Water quality is good although the aquifers are vulnerable to pollution from surface sources. Recharge occurs through flood events in these rivers. 8.4.5 Groundwater quality Selected indicators have been used to provide indicate the regional groundwater quality across the Limpopo Basin. These included Electrical Conductivity (EC (mS/m)), TDS (mg/l), Chloride (mg/l) and nitrate (mg/l). Unfortunately no data for Zimbabwe were available. These are displayed as contour maps in Figures 8.4 to 8.6. In terms of total salt



concentrations (TDS or EC) a number of areas are of concern. These are in the northeast of Botswana, on the Limpopo Mobile Belt rock east of Polokwane, in the southwest of the basin along the Limpopo River, and large areas in Mozambique. The brackish and saline conditions in Mozambique are linked to the depositional conditions, and to identify good quality aquifers under these conditions will be a challenge. It must however be remembered that these values reflect water quality at different depths and from different aquifers, and therefore these maps do not necessarily provide a realistic representation of the groundwater quality of a particular aquifer.

Figure 8.5: Groundwater quality expressed as TDS (mg/l ) across the Limpopo Basin.

The nitrate concentration map for Botswana and South Africa is displayed in Figure 8.6. There are several areas of alarmingly high concentrations (>250 mg/l) in both countries. Some of these can definitely be linked to agricultural activities, such as the Springbok Flats, and probably also some along the Limpopo River. Although high nitrate concentrations do occur in nature, the mechanism is not yet understood fully (Tredoux, pers. comm.). In the selection of pilot sites these cognizance needs to be taken of these areas. 8.5 Groundwater Recharge 8.5.1 Base flow estimation Table 8.4 shows the base flows estimated by Hughes (1999) for the different quaternary catchments along the Limpopo River. From this table it is clear that there is very little groundwater inflow into the Limpopo River; an indication of low groundwater recharge in the area.



Figure 8.6: Nitrate concentrations (as NO3) in groundwater of South Africa and Botswana.

Table 8.4: Estimated Base Flow in the Quaternary catchments along the Limpopo River (inside SA boundary) Hughes (SARES Program, 1999]

Quaternary Catchment A10A A10B A10C A32D A41D A41E

% No flow 49 48 53 50 48 43

Base Flow (mm) 0 0 0 0 0 .09

Figure 8.7 shows base flow separation, using the Herold Method, applied to flows measured at gauging station A7H003 on the Sand River (Midgly et al, 1994), one of the main tributaries of the Limpopo River in South Africa. The average annual estimated base flow has been calculated to be 0.27 Mm3. This analysis shows that the groundwater flux towards the Limpopo River is minimal, which similarly implies that the groundwater recharge is very low in the Limpopo River Basin adjacent to the river.



0

0.5

1

1.5

2

0 50 100 150 200Time (months)

Flo

w (M

m3/

mo

nth

)Measured flow Base Flow

Figure 8.7: Estimated base flow at gauge A7H003 (Herold method)

8.5.2 Chloride method for recharge determination By using the chloride concentrations in groundwater and rainwater, together with the annual rainfall in an area, groundwater recharge can be estimated. This was done for the Limpopo Basin in those areas where these three variables were available. Although groundwater chemistry is readily available for the basin, rain water chemistry is very sparse.

Figure 8.8: Groundwater recharge in mm/a and as a percentage of MAP for each of the main

hydrogeological regions



From experience gained in the basin, the variation in rainwater chloride content over most of the basin is known. In the interior, it averages around 1.0 mg/l, but at the coast it can be up to 8 mg/l. These values were used to calculate average groundwater recharge in mm/a for each of the seven hydrogeological regions in the basin. This is displayed in Figure 8.8. There is in good agreement with the values given by Vegter (1995). Because of a lack of groundwater quality information for the most northern region (Zimbabwe Craton), recharge values given by Larsen et al (2002) were used. Recently some stations have been set up in Botswana as automatic data collection platforms to allow continuous monitoring of rainfall, evapotranspiration, soil moisture and groundwater level data. The first of these stations was set up as part of the Serowe Wellfield Extension project. Additional stations (not in Limpopo basin) have been installed at Tsabong and Hunhukwe with a further station planned for Maun and possibly Letlhakane. No recharge values for these stations are yet available. 8.6 Groundwater Levels A groundwater level map for part of the basin is presented in Figure 8.9. According to this map there are a number of small isolated areas where water levels are >50 m below surface. As was the case with the water quality maps, these maps may reflect the water levels of multiple aquifers, and to not necessarily reflect the water level conditions of similar aquifers.

Figure 8.9: Groundwater levels (metres below ground level) Over the largest part of the basin in Zimbabwe the groundwater levels are indicated to be below 20 m. This is a reflection of the shallow weathered aquifers found on the basement granites of the area. The isolated areas of deeper water levels in Zimbabwe are in the Karoo basins where the aquifers are confined and overlain by basalt. These deeper levels are



perceived to reflect potentiometric levels. The deep water levels along the Zimbabwe Mozambique border are also believed to be associated with the confined aquifer conditions on the Nuanetsi sedimentary basin. The deep water levels just to the north of the Limpopo River in Mozambique, are indicative of deeper confined aquifers not hydraulically connected to the Limpopo River. 8.7 Groundwater Monitoring Groundwater monitoring is actively practiced in Botswana and South Africa. In Botswana the DGS is responsible for groundwater resources and basin monitoring as part of the National Monitoring Network. This network comprises 476 manually monitored boreholes, 37 autographic water level recorders and 17 rain gauges. The objective of the national monitoring network is resource assessment and protection. Boreholes that are part of the national network include both those in active and defunct wellfields. The data are collected every month. A summary of the Limpopo Monitoring Network is provided in Table 8.5. Unfortunately there is a significant backlog in data entry for the National Monitoring Network of Botswana. In South Africa the monitoring network is under review, but the existing one is not as extensive as the one in Botswana. Traditionally monitoring was directed towards areas were well fields were abstracting large volumes of water. The distribution of current monitoring stations is shown in Figure 8.10. Table 8.5: Groundwater Monitoring Network within the Limpopo Basin (Botswana) Location Monitoring points

1. Palapye 12 boreholes, including 2 automatic recorders and 1 rain gauge.

2. Ramotswa 40 boreholes + 1 well, 2 automatic recorders, data exist for 9 boreholes which are now blocked/dry

3. Mochudi 13 boreholes, Includes, 2 automatic recorders, data exist for 2 boreholes which are now blocked/dry

4. Malotwana 17 boreholes, Includes, 2 automatic rec orders, data exist for 1 borehole, which is now dry.

5. Molepolole 35 boreholes, Includes, 3 automatic recorders, data exist for 1 borehole, which is now dry.

6. Metsimotlhabe 14 boreholes, Includes, 1 automatic recorder, data exist for 2 boreholes, which are now blocked/dry.

7. Molepolole/Mochudi Exploitation

48 boreholes, data exists for 11 boreholes, which are now blocked/dry.

8. Serowe Automatic Data Collection Platform and 10 boreholes

9. Pitsanyane / Nnywane

22 boreholes, Includes, 1 automatic recorder, data exist for 4 boreholes, which are now blocked/dry.

10. Lobatse Treatment Plant

11 boreholes, data exists for 2 boreholes which are now blocked/dry.

11. Kanye 68 boreholes + 2 wells, includes 1 automatic recorder.



Figure 8.10: Map showing the distribution of groundwater monitoring stations in the Limpopo Province of South Africa.



9. SHARED WATER RESOURCES 9.1 Introduction Increasing trends of exploitation of the basin’s surface water resources, especially in the upper reaches of tributaries rising in South Africa, has led to sustained reductions in river flows in downstream reaches of the main stem of the Limpopo River. Much of the surface water exploitation in the basin states relies on storage reservoirs that have been constructed on perennial and seasonally flowing tributary rivers. Surface water use is directed primarily to irrigated agriculture, afforestation and the supply of domestic water to towns and communities, with somewhat smaller quantities being used to supply industry, power generation and mining activities. Recent estimates of water availability and projected demands for water in the four Limpopo basin states have demonstrated that portions of each country already face dangerous shortages of water that are exacerbated during dry periods. Whilst most urban communities receive adequate water supplies from formal reticulation systems, rural communities are those at greatest risk of failing water supplies. This situation is worst during dry seasons each year and may often reach critical levels during periods of extended drought. Projected trends in population growth indicate that this state of affairs will continue to worsen, whilst the anticipated effects of climate change are projected to add additional levels of water stress to the entire Limpopo basin. Much of the Limpopo basin’s irrigation potential has been compromised or restricted by the extent to which the basin’s surface water resources have been controlled and utilized. As a consequence, the actual area under large-scale or commercial irrigation is much smaller than the area of potentially irrigable soils. Inevitably, both rural and urban communities show a growing reliance on the exploitation of available ground water resources. Most rural communities draw their water supplies from shallow alluvial aquifers via boreholes and hand-dug wells; larger agricultural operations, as well as some mining and industrial operations that require larger volumes of water, depend on ground water obtained from boreholes. Several critical issues face attempts by the four basin states to co-ordinate management of water resources in the Limpopo basin. Foremost amongst these issues is the need to synchronize and harmonize water resource management systems between the respective countries. In particular, each country needs to formally combine surface and ground water resources in their planning frameworks, rather than dealing with these as separate resources to be managed by different organs of state. A central requirement here is the need for all parties to contribute towards the collection, interpretation and management of appropriate data, as well as concerted efforts to share data and knowledge equally between all parties. Here, the different roles and responsibilities of the public and private sectors have to be recognized, whilst public participation in decision-making processes also has to be promoted in each country. Whilst these suggestions may perhaps represent an ‘ideal’ situation, each of the four basin states engaged in managing the water resources of the Limpopo basin have initiated processes of wider public engagement and participation in policy making. In addition, these states are also promoting a greater sense of self-sufficiency amongst communities in terms of being responsible for managing local water resources. These initiatives represent a very welcome development and indicate a positive trend towards the ideal of Integrated Water Resource Management in the Limpopo basin. Against the background of escalating demands for water coupled with diminishing supplies of surface water in the Limpopo basin, there is a clear need for considerable additional work on



co-ordinated water resource management in the basin. Here, the key role played by ground water should not be underestimated. Indeed, the mutual dependence on the ground water resources of the Limpopo basin represents a significant opportunity for the respective basin states to work together to develop a mutually agreeable system whereby the water resources of the basin can be shared equitably and fairly amongst the participants. In turn, this could form the basis for co-ordinated planning and management strategies for the Limpopo basin and the development of an appropriate River Basin Organization (RBO) to manage the basin’s resources. If the basin states do not seize this opportunity, water resource exploitation patterns will continue to be both inequitable and unreasonable, with long-term adverse consequences for the entire basin. 9.2 Limpopo Alluvial Aquifers There are considerable differences between Botswana and South Africa in the present level of use of alluvial aquifers along the Limpopo River. Throughout the length of the Limpopo border between the two countries, there is consistent development of groundwater along the South African side evident, primarily for irrigation. Much more limited development has been undertaken along the Botswana side. Given the limited extent of the alluvial aquifers and their dependence on generally reducing surface flow resulting from ever more dams being built, there is significant potential for depleting groundwater storage. Detailed hydrogeological evaluation of the alluvial aquifers along the length of the river channel would form a critical foundation for sustainable and fair development. 9.3 River Flow Due to the importance of river recharge to both alluvial aquifers as well as fractured and fractured-porous aquifers adjacent and underlying the river channel, integrated management of all developments affecting surface flow including possible impact on groundwater resources will be crucial to optimal and reliable use of groundwater in the basin, particularly during drought periods. Hydrogeological assessment of extent of aquifer’s reliance on river recharge (perhaps in conjunction with an alluvial aquifer study) would be required to define how various flow regimes would affects aquifers and future development potential. 9.4 Karoo Aquifers A large Karoo basin is present in the Archaean basement terrain straddling the Botswana-Zimbabwe border in the Limpopo basin. Drilling in Botswana has shown that Lebung Group sandstones, underlying basalt, have considerable potential and appear to be actively recharged. Given the presence of this basin in extensive basement areas where groundwater potential is generally poor, its potential as an important resource, particularly during drought periods, seems clear. It would appear that at present only limited groundwater development of the basin has been undertaken on either side of the border, making it an opportune time to conduct a bi-lateral study to determine baseline conditions and better quantify the aquifer’s true potential. 9.5 Pollution With significant portion of the groundwater potential of this section of the basin being associated with alluvial and shallow fractured aquifers, effective resource protection will be important to safeguard the aquifers. As mentioned previously, one important dolomite aquifer (which is also shared by South Africa, has been contaminated by nitrate in Botswana due presumably to human habitation on the aquifer outcrop area. Additionally, acceptable water



quality of the rivers will be critical to ensure the quality of the shallow aquifers located near the Limpopo and its tributaries. 9.6 Coordinated Planning and Management All of the above issues revolve around the need for developing coordinated planning and management of groundwater as well as surface water for the riparian nations. This coordination would likely include developing an effective mechanism to promote and ensure data sharing, expanding existing commissions and working groups to include groundwater, improving both public and government level awareness, etc.



10. GROUNDWATER RELATED ENVIRONMENTAL ISSUES 10.1 Introduction This section provides a brief introduction to the environments of the Limpopo Basin with the emphasis on groundwater’s environmental role. This overview informs the selection of pilot study sites. It focuses primarily on the biophysical aspects of groundwater dependent ecosystems (GDEs), which are easier to assess at the basin scale than management systems. Management of groundwater and GDE resources at local, provincial, basin and regional scales will be assessed more fully once the pilot site(s) are selected. The environmental role of groundwater is not well understood and recognised within the Limpopo basin and much of SADC and Sub-Saharan Africa. There have been few links made in groundwater studies to environmental functioning and impact. Policies and legislation have often recognised the importance of surface water resource allocation and use to aquatic ecosystems, but less so the link of groundwater baseflow to aquatic ecosystems and rarely the important role in terrestrial systems (Colvin and Le Maitre, 2002). Groundwater related environmental issues are linked closely to the occurrence of GDEs and the goods and services they provide to society. These goods and services need to be considered with respect to the drought resilience they contribute to local economies and ecosystems, in addition to the perennial support they provide for sustainable livelihoods in rural areas, and economic gains at larger scales (e.g. tourism). Additional environmental issues linked to groundwater may be pertinent within the pilot study areas, and these should be scoped with stakeholders in further phases of the project. 10.2 Groundwater Dependent Ecosystems (GDEs) 10.2.1 Introduction to GDEs Groundwater Dependent Ecosystems (GDEs) are defined as those where the functioning of that ecosystem would be seriously affected if the availability of the groundwater was changed. Groundwater plays an environmental role both directly by sustaining ecosystems and indirectly through its interactions with surface water resources (Le Maitre et al. 1999; Winter et al. 1999). Ecosystems that depend on groundwater to sustain them can be divided into the following types (Hatton and Evans 1998; Colvin et al. 2002):

• Discharges from aquifers that maintains stream and river base or low flows; this includes interactions between surface water and groundwater in the river bed deposits;

• Discharge from aquifers that sustain springs and wetlands; • Discharge and water table levels that maintain cave ecosystems, typically in karst

environments; and • Water table levels which sustain terrestrial ecosystems by being within the rooting

depth of at least some components of the vegetation, typical of many alluvial aquifers. An ecosystem can be dependent on the quantity of water supplied by an aquifer, or the quality, or both. Dependence can vary from permanent to seasonal to necessary only during droughts.



If groundwater is available, an ecosystem will use that water in proportion to its availability and this is likely to have a significant effect on its structure, composition and dynamics (Tilman 1988; Hatton and Evans 1998). The most obvious evidence of this is a green gallery forest along a dry ephemeral river or around an oasis (Bate & Walker, 1993; Ward & Breen, 1983) and distinctive vegetation along faults and dykes (Scott & Le Maitre, 1998). Ecosystems with access to groundwater will develop some degree of dependence on it and that dependence is likely to increase as the aridity of the adjacent dryland environment increases (Hatton & Evans 1998). At the other end of the scale, permanently shallow groundwater will also prevent certain plant species from growing, for example the floodplain grasslands and palm savanna where there are few, or no, typical savanna tree species (Werger and Coetzee 1978). The response to changes in groundwater availability is difficult to predict, and can vary from a proportional change to an abrupt ecosystem collapse as a critical threshold is exceeded (Colvin et al. 2002). The depth to the water table is likely to be the most important hydrogeological parameter controlling the availability of groundwater to most dependent ecosystems. In coastal areas, salinity may be an important controlling factor and in other areas, the presence of nutrients. Groundwater quality may differ substantially from that of the surface water because of chemical reactions between it and the aquifer medium (Stanford and Ward, 1993; Sandström, 1996; Winter et al. 1999). The differences in chemistry can be important for sustaining the productivity of the surface water ecosystems that the groundwater interacts with (Fraser and Williams 1998; Stanford & Ward 1993; Winter et al. 1999). To understand what restriction should be placed on allocable groundwater we need to understand the nature, extent and degree of dependency of ecosystems on natural patterns of variation in groundwater fluxes, water levels and discharges from aquifers (Colvin et al, 2002). In addition, even a localised aquifer may support a keystone ecosystem which has a local importance greater than its geographical extent. The nature of the dependency is possibly the most difficult to predict and may only be realised once an ecosystem has been stressed beyond a critical threshold. 10.2.2 GDEs and their importance in drought preparedness Groundwater dependent ecosystems are often most vulnerable to groundwater impacts during drought and it is at this time that their role in the broader environment is most critical. Understanding the links and nature of the dependency between GDEs and the groundwater systems that support them is critical to the sustainable optimal use of resources in drought vulnerable areas. Similarly it is necessary to understand how different aquifer systems (dealt with in this report) and social systems respond to drought. Rural communities are dependent on groundwater during dry periods for both direct consumptive uses and indirect ecological services provided. Table 10.1 below lists many of the regulation, production, carrier and information functions that GDEs may fulfil in supporting rural and urban communities and the activities on which they depend such as subsistence agriculture or tourism. Making decisions about groundwater allocation becomes greatly complicated, not only by the conflicting requirements of users (often inter-related and inter-dependent), but also by the low confidence in predicting interactions between complex hydrological, ecological and social systems. It is important to try and address the low level of understanding we have currently in this area. The Limpopo basin provides a very interesting context of different hydrogeological and ecological systems which are critical for sustainable development. Additional scientific investigation of the links between these systems is needed. The challenge of bridging land-use and conservation management to integrated water resource management is significant in all the countries of the basin.



Table 10.1: Goods and services offered by ecosystems (Jansson et al, 1994).

Regulation Functions 1. Protection against harmful cosmic influences 2. Regulation of the local and global energy balance 3. Regulation of the chemical composition of the atmosphere 4. Regulation of the chemical composition of the oceans 5. Regulation of the local and global climate 6. Regulation of runoff and flood=prevention (watershed protection) 7. Water catchment and groundwater-recharge 8. Prevention of soil erosion and sediment control 9. Formation of topsoil and maintenance o soil-fertility 10. Fixation of solar energy and biomass production 11. Storage and recycling of nutrient 12. Storage and recycling of nutrients 13. Storage and recycling of human waste 14. Regulation of biological control mechanisms 15. Maintenance of migration and nursery habitats 16. Maintenance of biological (and genetic) diversity Carrier Functions 1. Providing space and a suitable substrate for: 2. Human habitation and (indigenous) settlements 3. Cultivation (crop growing, animal husbandry, aquaculture) 4. Energy conversion 5. Recreation and tourism 6. Nature protection Production Functions 1. Oxygen 2. Water (for drinking, irrigation, industry, etc) 3. Food and nutritious drinks 4. Genetic resources 5. Medicinal resources 6. Raw materials for clothing 7. Raw materials for building, construction and industrial use 8. Biochemicals (other than fuel and medicines) 9. Fuel and energy 10. Fodder and fertilizer Information Functions 1. Aesthetic information 2. Spiritual and religious information 3. Historic information (heritage value) 4. Cultural and artistic inspiration 5. Scientific and education information Current debates in the basin countries are focused on the obstacles to sustaining the biological resources of the basin, especially the need to arrest land degradation and deforestation. Other debates include those addressing land reform and tenure rights, devolution of authorities to local communities, and joint conservation efforts of shared ecosystems as in the Great Limpopo case. Significant efforts are being made to address past policy weaknesses, and to ensure that conservation and sustainable use of biodiversity, and equitable benefit sharing are an integral part of all socio-economic development. The four riparian states are conscious of the challenges of sharing this resource. Opportunities for cooperation and the possibility of conflicts are recognized by the four countries.



10.3 Aquatic Ecosystem Dependence 10.3.1 Summary This section provides and overview of aquatic ecosystems known to occur within the basin. Aquatic systems are prevalent in the lower basin, in Mozambique, outside of the drought vulnerable area. Groundwater here provides baseflow to coastal lakes, mangroves, wetlands and rivers. These impacts should be considered as distal receiving environments in drought management plans and the downstream cumulative impacts of groundwater management in the catchment should be recognised and considered. Springs and ephemeral aquatic ecosystems are more closely related to the drought vulnerable areas. Their role as keystone (and refuge) ecosystems in the broader environment needs to be understood in addition to the nature and extent of the their dependency on groundwater. 10.3.2 Springs

Groundwater level data are not available for the entire basin and the quality of existing data sets are uncertain. The spring map (Figure 10.1) shows the location of some springs in Botswana and South Africa. This data set is by no means complete, but does indicate the existence of springs in association with fractured basalt and quartzite litho-types. Specific species and ecosystem services (in addition to direct water provision) associated with these springs should be investigated where they fall within pilot sites for more detailed work. 10.3.3 Wetlands In terms of groundwater interaction, there is a continuum from springs, which have definite discharge points, to wetlands, where discharge tends to be diffuse. Groundwater dependent wetlands would include wetlands with a known or likely component of groundwater discharge in their hydrological cycle; at least some endorheic pans and many of the coastal wetlands are examples. The combination of low rainfall and high evaporation in the Limpopo Basin limits the occurrence and extent of wetlands in the catchment as a whole (Rodgers 1997). Ecologically important wetlands are found at sites along the Limpopo floodplain, notably at the confluence with the Levuvhu (Levuvhu) River, and in the lower catchment where they extend from below the confluence with the Olifants River to the coast (Table 10.2). As noted above there are extensive floodplain wetlands in the lower Changane River catchment, most of which are relatively saline (see Zambezian halophytics ecoregion) (Table 10.3). The Limpopo River floodplain has a wide variety of ecologically important wetlands, including pans, extensive floodplains, fresh ands saline lakes, and species-rich estuarine wetlands including mangroves. It has been estimated that wetlands comprise 2.8% of the land cover in the basin (World Resources Institute 1998 in SARDC/IMERCSA/ZERO 2002). Floodplain and riverine vegetation in the mopane ecoregions areas is typically a woodland of Faidherbia albida, Acacia xanthophloea, Lonchocarpus capassa and Combretum imberbe with Hyphaene and sometimes Phoenix palm species (Werger and Coetzee 1978). In the very sandy areas there is Julbernardia savanna or a Terminalia-Guibortia woodland. On the Mozambique coastal plain the floodplain vegetation is often an extensive grassland where there is a permanently or seasonally shallow water table and poor drainage. Savanna dominated by Acacia species and fringing forests with Ficus, Trichilia, Combretum and other forest species occur on higher-lying areas. Aquatic plant communities are found where there



is permanent surface water and swampy depressions often have palm savanna with Borassus , Hyphaene and Phoenix (see also the Coastal Forest Mosaic ecoregion, below).

Figure 10.1: Occurrence of Springs and Wetlands from available datasets. A number of the catchments in the Limpopo include areas of closed (endorhoeic) drainage (Midgley et al. 1994), which typically have one or more pans (playas), most of which are seasonally or ephemerally flooded (Allan et al. 1995). They are found in a wide range of substrates and geological settings, both hard rock and sedimentary deposits, and typically in very flat landscapes. The pans are probably not linked to deep lying aquifers but shallow primary aquifers contribute to the surface flows that reach them and to the maintenance of surface water in the pan once surface inflows have ceased. Many of them are relatively saline because of the closed drainage. They support a wide range of organisms which are adapted to the harsh conditions as well as a range or species that use them seasonally, notably wading birds. Ecologically important freshwater coastal barrier lake systems occur both north and south of the Limpopo but only a little information is available because no detailed studies have been done in this area. Some of the lakes may occasionally be connected to the sea and be more saline. These lakes are very important for migratory and breeding birds (e.g. terns, waders and herons) and provide habitat for many endemic plants and amphibians, and the fish stocks support local communities. The lakes are likely to be very sensitive to disturbance and are probably hydrogeologically connected with the Limpopo River, however they do not occur in drought vulnerable areas. The lakes connected to the sea may be similar to the Kosi Bay Lake System between Mozambique and South Africa which has 133 different fish spe-cies (UNDP 1998 in SARDC/IMERCSA/ZERO 2002). The wetlands known as “machongos” are associated with peat soils which are well-structured, fertile and yield good crops but are prone to acidification if they are excessively drained for agriculture (Gomez et al. 1998). The mangroves which occur on both banks of the Limpopo and extend for about 30 km in-land, are an important ecosystem because of their role as breeding areas for shrimp and



nursery areas for many marine fish species (Berjak et al. 1996; PAP/RAC/2000). They are vulnerable to changes in the flow of the river and lateral inflows of groundwater are needed to maintain the salinity levels that appear to maintain the balance between mangrove and salt marsh vegetation (Berjak et al. 1996). Tidal interchange and water level fluctuation extend well upstream of Xai–Xai, about 70 km from the mouth. A survey in 1957 found that the swamps extended for at least 8 km either side of the river and in 1998 there was an estimated 40 000–60 000 ha of swamp and floodplain below Chokwe (SARDC/IMERCSA/ZERO 2002). Although these ecosystems do not occur in drought vulnerable areas of the basin, they are impacted by cumulative impacts from the catchment as a downstream receiving ecosystem. These dependencies are currently being investigated in the neighbouring Inkomati system (Catchment to Coast, EU Inco-DEV project). Table 10.2: Ecologically important riparian wetlands recorded in the southern African portion

of the Limpopo Basin (from Rodgers 1995 and Cowan and van Riet, 1998). River system Notes Limpopo Between Matlabas and Mokolo confluences (1 000 ha) Limpopo-Levuvhu

Mabayeni to Levuvhu (Levuvhu) confluence (1 200 ha), potential Ramsar site

Nylstroom Nylsvley, Naboomspruit, provincial nature reserve (16 000 ha), Ramsar site Moleletsane Melrose Farm, north of Soutpansberg (16 000 ha) Mokolo Tambotie vlei, near Ellisras (800 ha) Sand Near Thabazimbi (500 ha) Mutale Mutale River in former Venda homeland (650 ha) Tshwana Bophutaswana (750 ha) Pienaars Near Themba (500 ha) Limpopo Vhembe reserve

Table 10.3: Major wetlands in Zimbabwe and Mozambique (Cowan and van Riet, 1998 in

SARDC/IMERCSA/ZERO 2002) Country Wetland type Mozambique Saline wetland and saltmarsh: Changane catchment

Swamp: Zinave National Park Floodplain: Limpopo, Changane, Olifants (Elefantes) River mouth/estuary: Limpopo

Zimbabwe Pans: Gorhwana, Bubye, Manjinji Swamp: Kwaluzi Riverine wetland: Gonarezhou National Park, Matopos N.P. Tuli safari area

10.3.4 Aquatic ecoregions Aquatic ecoregions have been developed using the geomorphological, geochemical and climatological features of southern Africa (Figure 10.2) (Allanson et al. 1990). Much more detailed classifications have been developed for South Africa which have used a range of other characteristics, such as flow patterns or aquatic organisms, but these have not been widely applied to southern Africa yet. There is ecoregional classification which has been developed specifically for use in ecological reserve determinations based, inter-alia, on geology, geomorphological landscape categories and vegetation types (Kleynhans et al. 1998), but this also has not been applied more widely yet. In the regional classification the Limpopo falls primarily into two regions:

• Subtropical coastal peneplain with a strong marine influence with coastal lakes and lagoons of varying salinity; surface water low in nutrients and subsoil water with raised salinity and an alkaline pH; aquatic fauna with tropical affinities and high diversity of waterbirds.



• Elevated plateau and south-eastern coastal plain with summer rainfall; drainage patterns superimposed on an ancient land surface (Karoo sedimentary rocks) and subsequently cut into the underlying rocks; surface water permanence ranging from permanent to temporary; suspended typically sediments high, total dissolved solids (TDS) high but <500 mg/l, the higher values coming from rivers draining catchments dominated by Karoo sediments, and pH 7.5-9.0; aquatic fauna diverse due to wide range of environments.

A third region, the arid west, just enters the western boundary of the catchment in Botswana and is characterised by almost entirely temporary (ephemeral) surface waters, high TDS and an alkaline pH.

Figure 10.2: Aquatic ecoregions of southern Africa 1 = subtropical coastal peneplain; 2 = elevated plateau and south-eastern coastal plain; 3 = elevated mountain massif; 4 = temperate acid, Western

Cape montane; 5 = arid west. For more information see the text. (Allanson et al. 1990 10.3.5 Fish and aquatic fauna The Limpopo main stem may have as many as 60 fish species with 54 of these, belonging to 16 different families, recorded in the lower reaches (UNEP/FAO/PAP/MICOA, 1998; SARDC/IMERCSA/ZERO 2002). Only three species are known to be endemic to the Limpopo river basin and Barbus treurensis is the only threatened species. Changes in the historical flow regime have resulted in the formerly perennial Limpopo main stem now being a seasonal river at least as far as Pafuri. The effects of this on the fish fauna are unknown. The changes in flow undoubtedly have had a significant impact on populations of the hippopotamus, Nile crocodile, Water monitors and water-dependent species such as otters and water mongooses but there are no records of these changes.



10.3.6. Endangered and Vulnerable Species The available data on endangered and vulnerable species are based on country and more detailed regional studies within countries, there has been no overview for the Limpopo Basin as such. The total number of species is fairly similar in each of the countries, except for plant species in South Africa. The high richness in South Africa is due to the wide range of environments while Botswana has the lowest numbers because of its largely semi-arid to arid climate. The highest numbers of threatened species, and the only threatened reptiles and amphibians, are found in South Africa. The most likely animal groups to be affected by changes in groundwater resources are the species dependent on surface water which can only be determined by examining the list of species for each country, a task which falls outside the scope of this project. The most directly linked groups will be most of the mammals, water birds, amphibians and freshwater fish. The threatened waterbirds include African finfoot (Indeterminate), Whitecrowned plover (Rare) and Yellow throated sandgrouse (Indeterminate). There are threatened amphibian species but none of these are apparently, confined to the Limpopo Basin.

Table 10.4: Total number of species and threatened species (T) by country and taxonomic group (WCMC 2001). Total number of birds includes only the species recorded as breeding; nd = no data.

Mammals Birds Reptiles Amphibians Freshwater fish

Plants Country

Total T Total T Total T Total T Total T No. T Botswana 164 5 386 7 157 0 38 0 92 0 2151 0 Mozambique 179 13 498 14 167 5 62 0 Nd 2 5692 57 South Africa 255 33 596 16 315 19 108 9 94 27 23420 1875 Zimbabwe 270 9 532 9 153 0 120 0 112 0 4440 73

10.3.7 Aquifer and cave ecosystems Aquifer and cave GDEs include groundwater contributions to “hypogean life” (subterranean), including those in the aquifer itself (Hatton and Evans 1998), and to associated above-ground cave ecosystems. Areas with karst geology, such as the dolomitic systems in South Africa and the limited section at the boarder with Botswana, are examples. Currently these systems are of academic interest and considered potentially important from a biodiversity perspective. It is not known how the hypogean systems relate to surface ecosystems and their relevance to the surface environment, particularly in the context of integrated water resource management, is not clear. 10.4 Terrestrial Ecosystems 10.4.1 Summary Where terrestrial vegetation is directly dependent on groundwater (as opposed to interflow) it is in areas where the groundwater body is within the rooting depth of the plants and groundwater discharge occurs through the plant root systems. This is also called “cryptic” discharge, and is most noticeable as oasis-type vegetation in arid environments. Figure 10.3 shows the rooting depth of plants in relevant environments. It is probable that areas of terrestrial groundwater dependency occur in the basin in the savanna and forest areas (as classified by White and WWF, see figures below). These are the most extensive classes present in the basin. The forest areas occur in shallow sandy coastal aquifers and are likely to use groundwater. However, these are also areas of high precipitation and soil moisture, therefore the degree of dependency may be low. Data are not available to infer the dependency on groundwater.



Figure 10.3: Average root depths for different vegetation types (after Canadell et al, 1996) In the semi-arid savanna areas with relatively shallow water tables of less than 40 m it is likely that deeper rooted plants such as Acacia use groundwater and are significantly dependent on it. Further interpretation of good quality water level data (for dry season periods) with vegetation lushness indicators derived from satellite data would give a clearer indication of the occurrence of terrestrial GDEs. These areas occur over fractured lithologies and a correlation with fractures, in particular the more extensive regional structures, could indicate groundwater dependency where the water table is accessible. Probably the most significant terrestrial dependency, in terms of environmental and social significance and drought vulnerability, occurs on the shallow alluvial aquifers in the ephemeral and seasonal reaches of the Limpopo and its tributaries. These systems are also important in that they are trans-boundary on the main stem, in terms of their locality and impact. Typically these aquifers are drought vulnerable, due to their low storage, and links to deeper aquifer systems could be important. Riparian zones and gallery forests of ephemeral rivers play a critical role in semi-arid environments in providing food, shelter and fuel. 10.4.2 Available information The region in which the Limpopo Basin falls is best known for its large mammal fauna (the big five) but has a rich and diverse flora and fauna. A number of studies have been done in the region and parts of it, mostly within each of the four countries involved, but no overview for the entire basin is available at present. Overviews with a bias towards the vegetation include those by:

• Werger and Coetzee (1978) and Cole (1986) of the plant communities and associations (phytosociology);

• White (1983) of the patterns in plant species distributions (phytochoria); • Scholes (1997) functional, process oriented approach based on Huntley (1982); • Botanical diversity and conservation (chapters in Huntley 1994);

-70

-60

-50

-40

-30

-20

-10

0

Desert trees

and shrubs Savanna Grassland Tropical

forest D

epth

(m

)

Max Mean



• ecozones (SADC/IUCN/SARDC 1994), ecofloristic zones (Sharma 1988 and Green et al 1996 in SARDC/IMERCSA/ZERO 2002);

• Ecoregions, a global analysis of biological diversity, threats, and global uniqueness which identified about 850 terrestrial ecosystems at the global scale (Olson et al., 2001)

Each of the countries also has maps of their vegetation types that are too detailed to go into here. The focus of this section is on giving a brief overview of the vegetation and the ecosystems with the emphasis on those which are most likely to be associated with, and potentially dependent on, groundwater. Wetlands are described in some detail because they are often the most obvious areas where groundwater is likely to interact with surface water and ecosystems but there are other forms of groundwater ecosystems which often go unrecognised. 10.4.3. Vegetation indicators of groundwater use Plants can utilise groundwater wherever their roots can access it and their roots systems can reach considerable depths, even through apparently impenetrable layers such as laterites (Le Maitre et al., 1999). Roots of woody species, trees and shrubs, generally reach depths of 5-10 m and several can reach depths of 10-20 m and more (Stone & Kalisz, 1991; Jackson et al., 1996; Figure 10.3). These include a number of South Africa’s indigenous species such as Boschia albitrunca and Acacia erioloba which can reach depths of more than 50 m. A trait of many winter-deciduous trees and shrub species, even in the arid areas of the basin, is the habit of flowering and producing their first leaves before the first rains at the beginning of the wet season (Werger and Coetzee 1978). This is thought to be due to their deep-rooted habit which enables them to tap water deep in the soil, including the unsaturated zone and the saturated zones where the water table is sufficiently shallow. Shallow water tables may be indicated by the presence of palm savanna or grasslands with scattered Parinari curatellifolia. The montane and highveld grasslands in Zimbabwe and South Africa also include extensive, usually grass dominated floodplain vegetation, much of which has been drained for agriculture or has become invaded by introduced tree species such as Acacia mearnsii. The Southern African Bushveld vegetation has a species-rich riverine and floodplain vegetation which can develop into a tall forest with Ficus, Albizzia, Syzygium and other tall tree species as found along the Olifants and Levuvhu Rivers in the Kruger National Park. Trees are a prominent feature of the ephemeral watercourses and riverbeds in the arid and semi-arid western parts of the basin. Important species include Acacia species, such as A. erioloba, A. karroo and A. albida, and sometimes Colophospermum mopane. 10.4.4 Vegetation types The vegetation types of the Limpopo Basin have been described in the rapid environmental appraisal (SARDC/IMERCSA/ZERO 2002) and only the key points will be dealt with here. There a several different interpretations and names for the different vegetation types. The most detailed assessment of the distributions and relationships between plant species and plant communities is the classification developed by White (1983, Figure 10.4). The dominant vegetation types in the basin are the Moist infertile and Mopane savanna which, together, comprise 75% of the area (Table 10.5). The Moist fertile savanna is also well represented at the SADC scale but the Limpopo is situated at the southern end of the Arid-fertile savanna, better known as the Miombo woodlands.



Figure 10.4: The distribution of White’s (1983) vegetation types based on plant species and plant community distribution patterns.

Figure 10.5: Distribution of the vegetation ecoregions within the Limpopo Basin (Olson et al. 2000; WWF 2001).



For this report the ecoregional classification developed by Olson et al. (2000) and documented by the World Wide Foundation for Nature (see WWF 2001) was selected . This classification is the first consistent global one and was developed using White’s (1983) work together with additional information on the plants and fauna which are important from a conservation perspective. The Southern Africa bushveld is the main ecoregion in the Limpopo Basin but is a minor ecoregion at the scale of the SADC countries where the Kalahari xeric savanna is the most extensive (Table 10.5). The Zambesian and Mopane woodlands are more representative and also the main vegetation of the Limpopo Valley where it is shared by Zimbabwe, South Africa and Mozambique (Figure 10.5).

Table 10.5: The area of the different vegetation types within the Limpopo Basin and all the SADC countries as mapped and described by White (1983) and the WWF (WWF 2001). (The names in the

map and table are based on the functional classification developed by Huntley (1982).

Limpopo Basin SADC countries Whites Description

Area (km2)

Area (%)

Area (km2)

Area (%)

Arid-fertile savanna 63 044 15 992 585 14 Desert 8 226 2 200 946 3 Moist-infertile savanna 174 506 42 2 551 947 35 Mopane savanna 135 016 33 600 966 8 Mosaics of forest 4 368 1 745 576 10 Unpalatable grassland 29 371 7 360 194 5 Total area 414 555 7 238 285

Limpopo Basin SADC countries WWF Description

Area (km2)

Area (%)

Area (km2)

Area (%)

Drakensberg montane grasslands, woodlands and forests

13 940 3 201 838 3

Highveld grasslands 22 835 6 185 718 3 Kalahari Acacia-Baikiaea woodlands 51 824 13 334 099 5 Kalahari xeric savanna 2 430 1 586 236 8 Maputaland coastal forest mosaic 2 283 1 30 119 0 Southern Africa bushveld 180 982 44 222 272 3 Southern Miombo woodlands 19 446 5 406 275 6 Southern Zanzibar-Inhambane coastal forest mosaic 2 089 1 146 227 2

Zambezian and Mopane woodlands 110 497 27 471 182 7 Zambezian halophytics 8 226 <0.5 30 250 <0.5 Most of the information that is available from the descriptions of these ecoregions is primarily applicable to dryland environments. The limited information for ecosystems that may be groundwater dependent has been summarised here. More detail on each of the vegetation types is given in Appendix A. The main groundwater dependent ecosystems in the Kalahari Xeric savanna and Semi-arid Kalahari Acacia-Baikiaea woodland are the tall trees, mainly Acacia species which occur at densities ranging from scattered trees to gallery forest along the ephemeral rivers. The riverine vegetation in the Southern African bushveld is generally a species-rich scrub or gallery forest with many species which are shared with the forest patches (Werger and Coetzee 1978). In Zambezian and Mopane woodland the riverine vegetation ranges from woodland to a tall gallery forest, often dominated by Ficus species. Other groundwater



dependent ecosystems would include floodplain wetlands, dominated by hygrophilous grasses, reedbeds and sometimes by tree communities. The Drakensberg Montane Grassland, Woodland, and Forest: is found in the upper parts of Drakensberg escarpment (Letaba and Olifants River catchments), the Soutpansberg and Blouberg and is characterised by grasslands with woody vegetation largely confined to less fire-prone habitats. The riverine and floodplain vegetation is grassland or low scrub or thorny trees (Acacia karoo, Ziziphus mucronata). The Highveld grassland ecoregion is characterised by low relief, meandering rivers and extensive grass, sedge and reed-dominated wetlands (Palmer et al. 2002). A wide variety of groundwater dependent ecosystems are found In the Coastal forest mosaic ecoregion of the Mozambique coastal plain and the Southern Miombo woodlands. The lower Limpopo and most of the Changane River floodplain is characterised by extensive alluvial deposits, pans, cut-off river bed sections pools. Numerous pans, swamps and vleis occur parallel to the coast. Palm veld with Hyphaene and Phoenix and an open scrub with Parinari curatellifolia occurs in low-lying areas with a shallow water table. Grass and sedge vegetation is found in areas which are waterlogged or seasonally flooded. Ecologically important mangrove vegetation occurs on the western bank of the estuary and on both banks for about 30 km inland of the river mouth in association with saltmarsh areas. The Zambezian halophytic ecoregion is found along the Changane River and in its floodplain where salts have accumulated. Fresh groundwater influxes and mixing with saline groundwater probably play an important role in determining the distribution of the halophytic (salt-loving) communities and freshwater communities. 10.4.5 Ecological importance of riparian areas Riverine areas and floodplains are important areas for biodiversity, offering refuges and habitats for a variety of organisms, especially in semi-arid to arid areas (Milton, 1990; Naiman et al., 1993; Rodgers 1995; Milton et al., 1997). The floodplain and riverine ecosystems of non-perennial rivers are supported by alluvial aquifers and the perennial systems receive a substantial proportion of local groundwater fed base flow (Figure 10.6).

C o a r s e a e o l i a n s a n d

A l l u v i a l s i l t a n d s a n d

A l l u v i a l s a n d a n d g r a v e l - a q u i f e r

C o a r s e a l l u v i a l s a n d - a q u i f e r

R a i n f a l l , g r o u n d w a t e r f l o w

P e r c h e d w a t e r t a b l e

A l l u v i a l c l a y a n d s i l t

Figure 10.6: Ephemeral riparian GDE. A cross-section of an ephemeral river system showing the layering of the alluvial sediments, perched storage off groundwater and deep rooting of the woody

plants (Colvin et al, 2002).

An example is the Sabie-Sand River system in the Kruger National Park where studies have highlighted the key role of the riparian ecosystem in maintaining the biodiversity and functioning of the adjoining terrestrial ecosystems (Davies et al., 1993; Jewitt et al., 1998).



Baseflow separation techniques suggest that groundwater may comprise a substantial proportion of the dry season flow (Vegter, 1995) that sustains the riparian vegetation (Birkhead et al., 1997). In some situations riparian plants may be using the more dependable groundwater rather than the surface flows and groundwater abstraction could affect these systems. 10.4.6 Degree of impact Humans have inhabited the Limpopo basin for 1 000s of years and their steadily growing populations have utilised, and over-utilised its natural resources for centuries, particularly during the past century. The basin has also been subject to considerable variation in key driving factors such as rainfall which, combined with the increasing pressure being exercised by modern man, is resulting in the degradation of the natural resource base on which those people depend. The Limpopo Basin has a total area of about 421 123 km2 (WRI 2000). Of this area, 67.7% is grassland (mainly acacia and mopane woodland), 47.3% is arid (dry acacia savanna), 0.7% is forest, 2.8% wetland, 4.5% is built-up area (mainly in South Africa), 26.3% is cropland, and 0.9% is irrigated agriculture (WRI 20001). Deforestation rates in the basin average around 5% per year which means a halving of the area of woody plant cover every 14-15 years. The has led to high erosion levels because the deforestation is often accompanied by the loss of the grass cover, soil compaction and excessive overland flow which causes erosion varying from sheet erosion to deep dongas. On average about 10% of the basin area is considered eroded. Almost all the original forest cover is thought to have been lost, most of this being in the coastal forest mosaic ecoregions of the coastal plain. Records of droughts and floods and their impacts have been discussed in section 5.2. Their effects on natural ecosystems have been magnified by the pressures created by the growing population on its natural resources. The effects of the regional droughts from 1991 to 1992, led to water rationing in Bulawayo, very low flows in the lower Limpopo due to over-abstraction (particularly in South Africa) and the loss of crops and wildlife (SARDC/IMERCSA/ZERO 2002; UNEP 2002). Little is known of the environmental costs and long-term consequences of the floods in February 2000 which resulted in major transformations of the lower Limpopo floodplain and dumped very large quantities of sediment into the coastal environment. Introduced (alien) species are widespread in southern Africa but there appear to have been few detailed studies of their impacts, other than aquatic weeds (but see UNEP 2002), except in South Africa (Versfeld et al. 1998; Le Maitre et al. 2000). Invasive aquatic species provide conditions which increase the prevalence of water-borne diseases, adversely affect water quality and aquatic life and block river courses, increasing the damage done by floods (CEP undated; Cilliers 1999; Hill 1999; Hill and Cilliers 1999; Van Wilgen et al. 2001; UNEP 2002). The most problematic species are water hyacinth (Eichhornia crassipes), red water-fern (Azolla filiculoides) and parrot's feather (Myriophyllum aquaticum). Terrestrial plants crowd out the native riverine vegetation, displace or affect populations of aquatic organisms and fauna and trap sediment which is then released when they are washed out by floodwaters. They also typically use more water than the natural vegetation they replace, deplete soil moisture, reduce groundwater recharge, spring flows, and river and stream base flows (Le Maitre et al. 2000). Many alien species can invade and replace natural vegetation and the rate of spread is enhanced by disturbances, whether natural or of human origin. One of the most aggressive invaders is Chromolaena odorata which is rapidly spreading northwards in South Africa and probably already occurs in southern Mozambique. The Limpopo and many 1 Percentages do not add up to 100% because the data were compiled from various sources and the categories were used by the sources overlapped and were not consistent (WRI 2000).



of its South African tributaries have been invaded by Australian Acacia species (Wattles), guavas (Psidium guajava), bugweed (Solanum mauritianum), lantana (Lantana camara), jacaranda (Jacaranda mimosaefolia), syringa (Melia azedarach), amongst others (Versfeld et al. 1998). These species are likely to have widely dispersed by the floods of February 2000. Control operations are very expensive, take several years to complete and require ongoing follow-up surveys to deal with new colonists. Relatively moist environments often seem to be the most susceptible invasions and the most severely affected. Casuarina species are aggressive invaders in the dunes of the Zululand coast, South Africa, and have become established in the dune areas at the Limpopo River mouth (UNEP/FAO/PAP/MICOA 1998) The human populations in the basin have been having an increasing impact on its natural resources for centuries (Ashton et al. 2001; SARDC/IMERCSA/ZERO 2002; UNEP 2002). The rapid population growth experienced during the last century has resulted in many communities living close to or exceeding the carrying capacity of their natural resource base. This was aggravated in South Africa and Zimbabwe by the expropriation of “tribal” lands for commercial farms, usually owned by whites, and forcing the displaced people to move to already overcrowded “homelands”. The hardest hit have been the poor who lack the skills and resources to add value to their resources and have become trapped in a cycle of increasing poverty. Numbers of livestock increased as security was sought in ever larger herds, resulting in serious over-grazing. The net result is over-harvesting of natural resources such as wildlife, fish stocks, indigenous food and medicinal plants and fuelwood, reinforcing the poverty cycle. The increasing poverty has also resulted in the breakdown of the traditional laws and customs which regulated access to, and use of, land resulting in serious land degradation in large areas of Zimbabwe and South Africa. The diverse mammal fauna characteristic of the natural vegetation of the basin is now almost entirely confined to conservation areas. Large areas of the higher rainfall parts of the catchments have been converted to cultivated land, often irrigated and commercial pastures. Mining, both formal and informal, has had a significant impact on the basin, particularly on the quality of the water draining from the mined areas (Ashton et al. 2001). The most extensive mining areas are situated in South Africa along the southern margin of the basin, particularly in the Olifants (Elefantes) River catchment. The large areas of open cast coal mining have increased the amount of water reaching the groundwater; these waters are highly acidic (pH of 2.0) and the resulting groundwater discharges are having a significant impact on the aquatic life of the streams and rivers draining these areas. Heavy metals have been recorded in fish collected as far downstream as the Kruger National Park. There are plans to prospect for, and potentially mine the heavy minerals in the dunes of the Mozambique but most of this will probably occur to the north of the Limpopo Basin. In some cases the river flow patterns have been changed by significant inflows of water from sewerage works in large urban areas, for example the Pienaars River flowing northwards from Pretoria (Boroto and Görgens 1999; Ashton et al. 2001). This surface water may contain a range of pollutants but their effects on groundwater resources connected to the river are unknown. Irrigation return flows also are often polluted with nitrates due to excessive fertilisation, pesticides and herbicides. The importance of the impacts of these pollutants on the aquatic ecosystems and groundwater in the Limpopo basin has not yet been investigated. Return flows from the Chokwe irrigation scheme are believed to be increasing the salinity problems in affecting water quality in the Limpopo downstream of the irrigated areas (UNEP/FAO/PAP/MICOA, 1998). Discharges of raw effluent at Xai-Xai are probably having adverse effects on the water quality and ecosystems downstream of the town (UNEP/FAO/PAP/MICOA, 1998). The development of numerous large, medium and small dams has undoubtedly altered the hydrology of the Limpopo River, changing it from a perennial river to a seasonal river for about ¾ of its length (Boroto and Görgens 1999; Ashton et al. 2001). The size of these impacts is dealt with in sections 5.6 and 6); it is clear that the total flows have decreased but



there has also been a shift in the season with parts of the river having raised dry season flows due to, for example sewerage discharge and irrigation return flows. These changes have had a significant impact on the water-dependent and aquatic fauna (see section 10.2) and also on the vegetation, particularly the riverine and floodplain woodlands and forests and mangroves. 10.4.7 Conservation areas The total area of conservation areas of various kinds the Limpopo Basin is some 57 538 km2, most of which is found in South Africa (Table 10.6). The best protected ecoregion is the Southern African Bushveld with many areas conserved in National Parks, provincial nature reserves, conservancies and private game farms. Large areas of the Zambezian and Mopane woodlands, and the associated riparian woodland and forest, are protected within the Kruger National Park and other reserves along the Limpopo valley. More will be protected in future once the proposed Gaza–Kruger-Gonarezhou Transfrontier Park (95 700 km2) becomes established (Peace Parks Foundation 2000), adding to the roughly 40% of this ecoregion that is already protected. A small portion of the Southern miombo woodland ecoregion in the basin is protected in the Zinave National Park in Mozambique and a small portion of the Zambezian halophytics ecoregion is protected in the Banhine National Park, Mozambique. None of the Kalahari arid woodlands ecoregion in the basin is protected but large areas are protected elsewhere in Botswana. The most poorly protected vegetation type is the Springbok Flats (southern African bushveld) where only one percent is conserved within the Nylsvlei Nature Reserve. The Kalahari Acacia-Baikiaea woodlands of the Limpopo basin, most of which occur in the so-called “Hardeveld”, are densely populated (±80% of Botswana’s people) and poorly protected with only one reserve: the Stevensford Private Game Reserve on the north bank of the Limpopo, near the town of Palapye (WWF 2001; not included in the totals below).

Table 10.6: Area of the Limpopo Basin which is conserved in some form of reserve by country and conservation status. Summarised from data supplied by the Peace Parks Foundation.

Country Class Area (km2) Botswana Game Reserve 415 Mozambique National Park 11 259 South Africa Game Reserve 553 South Africa National Park 19 691 South Africa Nature Reserves 1 306 South Africa Private Reserve 291 South Africa Protected Area 18 470 South Africa Wilderness Area 14 South Africa Sub-total 51 999 Zimbabwe National Park 5 359 Zimbabwe Protected Area 9 Zimbabwe Safari Area 172 Zimbabwe Sub-total

Total (SA & Zimbabwe) 5 540

57 539 The planned Dongola/Limpopo Valley Trans Frontier Conservation Area (TFCA) will include another 4 900 km2 of South Africa, Botswana, and Zimbabwe. The TFCAs will be important for the conservation of the Limpopo River itself because they will link the management of both river banks; all of the existing conservation areas only involve one or other bank and reserves on each of the banks rarely coincide. The Drakensberg montane grasslands, woodlands and forests ecoregions in the Soutpansberg and Blouberg mountain ranges includes more than 100 endemic grassland species (Low and Rebelo 1998). Bird and reptile species richness is also quite high. This ecoregion is recognised as one of the 200 terrestrial ecosystems that is a globally important priority for conservation (Olson et al. 2000).



10.5 Recommendations for GDE Site Selection Based on the overview presented above, it is recommended that the following issues be taken into consideration in the selection of sites for further study, to ensure that GDEs are included.

• An area that is vulnerable to climatic drought as indicated by low precipitation, high aridity and high coefficients of variation for precipitation.

• An area that includes trans-boundary water resources or ecosystems (in particular the riparian zone).

• An area that is representative of the hydrogeology of drought-vulnerable areas of

SADC. This should preferably include a shallow alluvial and/ or basement aquifer in addition to a deeper (more drought resilient) aquifer such as a fractured basement or Karoo aquifer.

• An area that is representative of both highly impacted land-use and relatively pristine conservation area (Table 10.4). Figure 10.7 shows conservation areas and parks. Monitoring similar ecosystems in each of these settings will give some indication of anthropogenic impacts. The level of alien species invasion and human population density could also be considered in terms of impact.

• An area that includes both terrestrial and aquatic GDEs. The aquatic GDEs may be seasonal.

•

Figure 10.7: Conservation areas within the basin

10.6 Recommendations for Future Work A key objective of this project is to identify pilot activities necessary to recognise and sustainably manage GDEs in the pilot areas. A framework to assess the occurrence and



importance of GDEs in relation to drought preparedness is recommended (below). The GEF project should link to existing initiatives active in the pilot areas to ensure maximum incremental value. Existing projects of relevance to the GEF groundwater project are discussed under step 8. Sections 10.3 and 10.4 described some of the ecosystems and settings where there may be GDE in the two pilot areas. Step 1: Identify key hydrogeological typesettings and discharge environments Hydrogeological type-settings are outlined in Section 8. Identifying type settings based on broad lithological and hydrogeological parameters enables a simplification of the complex groundwater and ecological systems. Groundwater discharge characteristics within these types are of great importance. Understanding where groundwater is discharging as springs, seeps, baseflow to rivers or cryptically by evapotranspiration from terrestrial vegetation is a critical first step in identifying GDEs. The most obvious indicator of this is groundwater levels and springs. In the type-settings which relate to secondary aquifers, an interpretation of structural controls on groundwater discharge is essential alongside a characterisation of structural features. This activity requires the detailed investigation of groundwater level data, remote sensing analysis of vegetation lushness and geological structure. Step 2: Identify potential GDEs at points of groundwater discharge. At potential discharge areas (as characterised above) identify ecosystems which contrast with areas where groundwater is not available for environmental use. A comprehensive range of tools is recommended for terrestrial environments in Southern Africa in Colvin et al, 2002. Identification of aquatic environments will require a determination of groundwater fed baseflow contributions to rivers and a correlation of the occurrence of wetlands and lakes with potential hydrogeological discharge features such as faults or lithological contacts. Step 3: Characterise the GDEs in different hydrogeological environments. Monitor the ecosystem health of GDEs in conjunction with groundwater discharge parameters. Groundwater levels, estimates of discharge volumes and hydrogeochemical parameters relevant to the setting (e.g. salinity, nutrients, trace elements) should be monitored at the appropriate (variable) frequency. In conjunction, the health of the GDE indicated by species occurrence or diversity, leaf area index, lushness, growth, water levels, etc, should be monitored. The tools most appropriate for this monitoring will vary on a site-by-site basis. Both spatial and point data should be collected and it is expected that some remote tools will be necessary. Step 4: Identify the nature, extent and degree of dependency of the ecosystem on

groundwater. An assessment of GDE health correlated to groundwater characteristics should be undertaken by a team of scientists which includes ecologists intimately familiar with the system, in addition to hydrogeologists sensitive to the environmental role of groundwater. The assessment should indicate when the ecosystem is most dependent on groundwater and what are the critical hydrogeological features that maintain its role (e.g. water levels, salinity, etc). It should also indicate the extent of direct and indirect ecosystem links to groundwater and likely impacts if the hydrogeological regime were disturbed by changes in anthropogenic or climatic influences.



Step 5: Identify and quantify the goods and services delivered to society from the GDEs. Table 10.1 indicates typical goods and services delivered by ecosystems. Socio-economic or ecological economic expertise will be required in the assessment of the local and related economic systems and their links to GDEs (as well as in further steps 6 to 8). A full analysis of the rural economic base should be conducted. Step 6: Identify goods and services which contribute to drought resilience within the

local society and economy. Table 10.1 indicates goods and services which may be linked to increased drought resilience within society. These should be identified on a site-by-site basis. The vulnerability of various economic activities to hydrological variability should be assessed. People in the pilot areas have indicated that the impacts of floods are frequently more devastating than droughts. Some activities may be almost independent of the hydrological cycle (mining), some closely dependent (rain-fed agriculture), others linked via indirect impacts (tourism). Catchment based water flows (including groundwater) should be assessed in conjunction with local economic transfer (flows) of monetary value and services. Step 7: Give an indication of the value of the environmental role of groundwater (with

special reference to drought preparedness). The socio-economic benefits and values of these services need to be understood in the context of drought preparedness. Decision makers (and stakeholders if they are not the direct decision makers) need to appreciate costs and benefits in the trade-off of allocating groundwater to consumptive uses in under drought conditions or reserving it to maintain ecological functioning. This should be communicated through illustrative scenarios which describe the ecological, social and economic consequences of different water allocations. Clear distinctions need to be made in terms of allocations and drought-mitigation use of groundwater which may impact GDEs and that which may be allocated from aquifers with no environmental connection in that area. Step 8: Assess the current management systems which relate to GDEs and indicate

how they may be strengthened to implement the necessary protection mechanisms and derive optimal benefits for drought preparedness.

This should include an assessment of local, national and transboundary management systems, impacts and benefits. The two pilot areas include approximately 20% of land under conservancy management, either through trans-boundary, state or private control. The proportion of local, national and regional income derived from eco-tourism linked to these conservancy areas isn’t known. Clearly, the conserved natural environment is an important contributor to sustainable development in the pilot areas and the management of groundwater use and protection needs to be linked to the broader management of natural resources. At a trans-boundary level, natural resource management occurs in the Trans-Frontier Conservation Areas coordinated by Peace Parks. The GEF project should link to the conservation work coordinated by Peace Parks to assess impacts and value of the environmental role of groundwater in a trans-boundary sense. At a national level the South African National Parks Board (SANPB) manages several parks within the pilot areas. In



particular, the largest park, Kruger, has a well established scientific research plan, which currently aims the address the issue of groundwater dependency. National Parks are found in both Zimbabwe and Mocambique in the Eastern Pilot, and whist groundwater is not specifically addressed in their conservation management at present, there is an opportunity to interact with the national parks boards via the GEF project. In Zimbabwe, the Communal Areas Management Programme for Indigenous Resources (CAMPFIRE) addresses the links of sustainable livelihoods to conservancy and non-destructive use of resources. Links with this programme should be established and the value of indirect groundwater use assessed. In the Western Pilot area the proposed Limpopo-Shashe Transfrontier Conservation Area is centred on the Shashe Limpopo confluence. The core area for the South African part of the TFCA is based on the Vhembe Nature Reserve. The reserve has been taken over by the South African National Parks Board and is in the process of being expanded to form the Vhembe-Dongola National Park. The SANPB is busy developing tourist infrastructure in the park at present. To the south of this core area there are the Limpopo Valley Game Reserve and the Venetia Limpopo Nature Reserve. In Botswana the Northern Tuli Game Reserve is situated in the north-west corner of the Tuli Block, across the Limpopo from South Africa and across the Shashe from Zimbabwe. Zimbabwe currently does not have a conservation area except for the Tuli Circle Safari Area. Two farms on the northern side of the Limpopo River in Zimbabwe – Sentinel Ranch and Nottingham – may still be incorporated in the TFCA. In addition to creating a conservation area that spans the Limpopo River, the area includes the very important Mapungubwe site which dates from the African iron age period shortly after the Great Zimbabwe empire collapsed. The Maramani communal land occupies a triangle of land between the Sentinel Ranch and the NTGR and negotiations are underway to see if this land can form part of the proposed TFCA. The Greater Limpopo TFCA is much further developed and already has entered the stage of negotiations around cross-border access. It includes three national parks, Gonarezhou in Zimbabwe, the recently proclaimed Limpopo in Mozambique and Kruger in South Africa. Negotiations for further expansions are underway, particularly the corridor that will link Gonarezhou and the Kruger Parks. It also has a number of African Iron Age settlements, including Thulamila in the park and at Gumbu and Mabyeni in the Madimbo area to the west of the Kruger Park.



11. GROUNDWATER MANAGEMENT ASPECTS 11.1 Institutional Structures in the different Limpopo River Basin Countries The approach to groundwater management differs significantly from country to country and hence the level of efficiency also differs. This maybe attributed to a number of reasons or prevailing conditions such as the level of development, availability of resources (human and financial) and so forth. Although the generic outlook may look similar the level of responsibilities and efficiency on which those responsibility are taken also differ significantly from country to country. This to a large extend is closely related to the prevailing socio-economic conditions. The table below represents the groundwater management structures in different countries, it also indicates the levels at which different functions are performed. This is based on the interaction with various role players within the groundwater management system in different countries during the field work and also on the responses to the questioner sent out to people in different countries. What can be noted is that there are certain functions that are performed at the same levels in different countries and there are others that are performed at different levels in different countries. This is also to an extent dictated by the availability of resources. Table 11.1 shows the different groundwater management systems and institutional arrangements in the four countries forming the Limpopo River Basin. 11.2 Regional Context Africa wide, the New Partnership for African Development (NEPAD) aims to eradicate poverty and to place African countries, both individually and collectively, on a path for sustainable growth and development, and at the same time to participate actively in the world economy and body politic. Within this framework, the African Ministerial Conference on Water (AMCOW) identified the following key issues at the Bonn 2002 International Conference on Freshwater: governance in the water sector; inter-governmental dialogue for water security; financing; management capacity building; technology transfer; urban water demand; basic human needs; gender representation in water management; linking catchment environments to the coast. In 2002, AMCOW decided on the following key elements in an African Regional Programme of Action:

• Develop a regional support programme to strengthen water sector reforms; • Seek support for the establishment of a Regional Water Technology Collaborating

Centre for Africa; • Develop a regional strategy and plan for technical/ advisory services; • Promote actions which will realise the African Water Vision; • Designate the African Water Task Force to play the role of ‘Regional Water Watch’.

The Accra declaration, which informed the AMCOW contribution to the World Summit on Sustainable Development, focussed on paving the way for clear policies and commitment to eradicate poverty, reduce water-related diseases and achieve sustainable development in Africa (Africa Water Task Force, 2002). Specifically the Accra declaration states that African water ministers will support sustainable development by:

• Improving access to safe water supply and sanitation to reduce the proportion of Africans without access to basic water supply and sanitation by 50% by 2015 and 75% by 2025 as well as promoting good hygiene.



Table 11.1: Institutional water management levels in the different Limpopo River Basin countries Country

Level Functions Botswana Mozambique South Africa Zimbabwe

Water Custodian ? ? ? ? Formulating water laws and policies ? ? ? ? Water Providers ? Supporting and managing water catchment agencies/councils

? ?

Funding and managing water and sanitation projects

? ?

Identifying, assessing and testing groundwater resources ? ? ?

Monitoring abstraction, water level and water quality

? ? ? ?

Maintaining and updating national groundwater database

? ? ? ?

Honouring international obligations/agreements

? ? ? ?

Ensuring Integrated Water Resource Management ? ?

National Department of Water Affairs

Regulate the issuing of water use licences

? ?

Responsible for water quality related issues

? ? National Health Department Water quality monitoring ? ? ? ?

Regulate and Licence the drilling of new boreholes in farming areas ?

Land Board Register newly drilled boreholes ? Implementing water and sanitation projects

? ?

Exploring, drilling and equipping of new boreholes

? ? ? ?

Regional management and monitoring of water resources ? ? ?

Supporting local districts/council in water provision

? ? ?

Regional/Provincial Offices

Operation and maintenance ? ? Water provision ? ? ? Operation and maintenance ? ? ? ? Local management and monitoring ? ? ? ? Cost recovery ? ? ? Managing water schemes ? ?

District/Local Authorities

Water and sanitation project implementation ? ?

Monitoring proper usage of water within the villages

? ? ? ?

Serve as community representatives ? ? ? ? Contribute in the formulation of water policies at village level

? ? ? ?

Liaise with authorities on any water related issues/problems ? ? ? ?

Manage community based water schemes

? ?

Operation and maintenance ? ? ? ?

Village water committee

Cost recovery ? ? ? ? Day to day operation of pumps Basic maintenance and repairing of pumps and related water infrastructure

? ? ? ? Pump Operators

Basic monitoring and data capturing at village boreholes

?



• Promoting efficient and sustainable use of water to address food security and income generation, helping to halve the number of malnourished people by 2015 through investment in irrigated agriculture focusing on economic development as well as on food self-sufficiency, enhancing access to markets and building partnerships for funding and learning.

• Using integrated water resource management (IWRM) to promote cooperation in national and shared water basins for the mutual benefit of all water users and their communities and to increase public awareness and strengthen the political will.

• International water basins provide opportunities for regional co-operation, development and integration. Arrangements must be established and strengthened to benefit all riparian countries with assistance to and support for local and national initiatives.

• Acting to prevent, mitigate and manage water-related disasters by developing a prevention based culture, strengthening capacity to monitor and mitigate climate variability and to manage disasters.

• Focusing empowerment and capacity on improving equity and gender sensitivity and promoting pro-poor water governance and water policies.

All these activities must be undertaken in a manner designed to protect the natural environment. It will only be possible to sustain access to safe water and hygienic sanitation and create sustainable livelihoods using water if we tackle the underlying poverty of many African people. Water-based initiatives must link with broader efforts to promote sustainable development in Africa. Cooperation to improve economic conditions so Africa can meet its own needs is crucial. The focus areas outlined above are critical imperatives to overcome some of the key problems in water resource management prevalent throughout the region. Grey, has summarized some of these problems and constraints, as illustrated below, in terms of a resource legacy (limited storage, deteriorated water sheds and water quality) and a historical legacy of trans-boundary resources, poverty and limited capacity.

Water Resources Legacy

•Hydrological Variability•International Rivers

Poverty•Low infrastructure stock

•Limited capacity •Regional fragmentation

Risk•Economic

•International political

WRM Gaps•Limited storage

•Degraded watersheds•Inefficient utilization•Deteriorated quality

Policy Responses •Water resource policy

•Economic policy•Foreign Policy

Figure11.1: The vicious circle of water resource management in Africa. (Source: Grey, 2002)



Within SADC the SADC Water Sector Coordinating Unit has been set up to facilitate regional cooperation in sustainable water management. 11.3 Botswana Water is regarded as public good in Botswana and the main body of laws directly concerned with water comprises four statutes, namely; The Water Act of 1968, The Boreholes Act of 1956, The Water Works Act of 1962 and The Water Utilities Corporation Act of 1970. Some of these statutes remained unchanged since coming into force while some have been amended to cover new and changing circumstances. The Water Act of 1968 is the basic water statute for Botswana. It contains common law aspects of water and these include, but are not limited to the following: the status of public water; the inherent rights of individuals to use of water; the recording, granting, variation and termination of formal rights to use or impound water. The Borehole Act (1956) is a short statute which deals in part with drilling of boreholes or water wells in Botswana, whiles the Waterworks Act (1962) provides for the constitution of water authorities in areas designed by the Minister of Minerals, Energy, and Water Affairs. Subsequent Efforts have been as follows: a) Botswana Commissioned National Water Master Plan and report was submitted in 1991. Volume 11 of this report addressed the legislation issues; they have not yet been accepted. However, Botswana will be soon commissioning Review of the Master Plan and will address these issues. b) National Conservation Strategy Agency (NCSA) a government body has formulated a policy on National Resources Conservation and Development in 1990 and this policy is being supported by legislation and the effort to develop the act started in 1992. It is envisaged that this will be put into practice within a year. NCSA’s mandate is also to develop sector – specific guidelines and develop manuals that will be used to assist in the implementation of the proposed draft act. Sector specific guidelines will be developed in conjunction with relevant ministries responsible. The Proposed Water Act as discussed above has provisions for protecting groundwater. This Act allows for the declaration of protected areas wherein certain activities might be protected by the order of minister; where the discharge of certain waste might be prohibited. 11.4 South Africa 11.4.1 Legal framework Water management in South Africa occurs within the framework of the National Water Act (Act 36 of 1998) and the Water Services Act (Act 57 of 1996). The National Water Act (NWA) deals with the management of water resources, including groundwater. This act changed the previous status of groundwater by specifically addressing all water resources, including groundwater, in an equal manner as a common resource under the custodianship of the Minister of Water Affairs. The objective of the Act is to achieve the sustainable use of water for the benefit of all users. It aims to do this through participative, integrated water resource management delegated to a catchment level. South Africa has been divided into 19 Water Management Areas and the formation of Catchment Management Agencies is in progress.



The diagram below indicates the high priority given under the NWA to international water obligations. Water should be allocated to meet the needs of The Reserve and Resource Quality Objectives and International Obligations, before further allocations can be made. The NWA also aims to promote water use efficiency and optimal beneficiation of water resources. These issues should be taken into account in the licensing process. The main objects of the Water Services Act are to provide for-

(a) the right of access to basic water supply and the right to basic sanitation necessary to secure sufficient water and an environment not harmful to human health or well-being;

(b) the setting of national standards and norms and standards for tariffs in respect of water services;

(c) the preparation and adoption of water services development plans by water services authorities;

(d) a regulatory framework for water services institutions and water services intermediaries;

(e) the establishment and disestablishment of water boards and water services committees and their duties and powers;

(f) the monitoring of water services and intervention by the Minister or by the relevant Province;

(g) financial assistance to water services institutions; (h) the gathering of information in a national information system and the distribution of

that information; (i) the accountability of water services providers; and the promotion of effective water

resource management and conservation. The Water Services Act prescribes the role of local government in meeting the water and sanitation needs of people whilst acknowledging that the Department of Water Affairs and all spheres of government should cooperate to enable the delivery of these services. The Act also makes provision for the development of standards and guidelines. The National Disaster Act (Act 57 of 2002) coordinates the Provincial and local governments in their response to droughts. The National Disaster Management Centre is coordinated by the Department of Provincial and Local Government. 11.4.2 Institutional arrangements The South African water sector is undergoing transformation to include new institutions required by the legislation of the late 1990s. These institutions include Catchment Management Agencies, Water User Associations and Water Service Providers. The current DWAF guidelines on groundwater management as part of IWRM within the legal framework indicate the various institutions relevant to groundwater management. These are shown above.

Reserve Water required for RQ0s

Water required for international obligations

Water required for Schedule 1 uses, General authorizations and existing lawful use

Water for licensed allocations



11.4.3 Standards and guidelines The Standards South Africa (STANSA) division of South African Bureau of Standards is in the process of producing a code of practice for the development, management and maintenance of groundwater resources including borehole construction and rehabilitation standards. DWAF has produced guidelines on groundwater management for IWRM within the new Water Management Areas. These are being tested in pilot areas currently. 11.5 Zimbabwe The Minister of Rural Resources and Water Development, on behalf of the Zimbabwean Government is the custodian of all water resources in Zimbabwe. Groundwater is considered to be a public resource administered by the Minister in an equitable and sustainable way and no person shall be entitled to ownership of any water in Zimbabwe. The Minister is further also responsible to give effect to international agreements signed by Zimbabwe on shared watercourse systems in a spirit of mutual co-operation. In terms of water management, Zimbabwe is divided into seven Catchment Councils. These report to and are managed by the Zimbabwe National Water Authority (ZINWA), which in turn reports to the Minister. Integrated water resource management is the legal responsibility of these Catchment Councils, through the establishment of "Outline Water Development

Groundwater Manager

Catchment Management Agency

Consultants Other Water Managers

Water User Associations

Catchment Management Committee

NGOs

Provincial Government

Water Services Committees

Water Services Institutions

DWAF



Plans". Although the management of water resources is delegated to the Catchment Councils, the Minister provides national guidelines for water resource development, utilisation and management. On the other hand, Catchment Councils may appoint sub-catchment councils managing specific smaller river basin systems. The allocation of groundwater for use is controlled by a system of permits. All groundwater use, other than for basic human needs and for aquatic eco-systems, will require a permit granted by Catchment Councils. The responsibilities of Catchment Councils include the issuing of permits, monitoring of groundwater levels and abstraction volumes, water quality, quality Water use efficiency is among other factors considered for granting a licence for groundwater use. When issuing permits water use efficiency is taken into consideration. Due to shortage of manpower, monitoring of the groundwater resources is currently not taking place. ZINWA on the other hand is responsible for the registration of all boreholes nationwide and for the capturing of all borehole data into a groundwater database. Groundwater data are initially captured into a regional database, then forwarded to the national database kept by ZINWA. ZINWA is also responsible for water provision under all circumstances. During periods of drought, conjunctive use of water resources is common in the low rainfall regions of the country, where surface water resource are limited. In severe droughts, were both surface and groundwater are not available, the local district council may affect water cartage. Either the Government or other institutions responsible for water resources are currently practicing no official artificial recharge of groundwater in Zimbabwe. Water management has been participative to some degree through the establishment of water committees among groundwater users, especially in rural communities. This aspect of groundwater management will be enhanced with the formulation and implementation of the proposed Outline Water Management Plans for the various catchment areas. No stakeholder forums or water user associations are currently active in the Limpopo Basin of Zimbabwe. 11.6 Moçambique The information presented here is taken from the draft country report for SADC WSCU Common Minimum Standards. No further information is available which relates specifically to the Limpopo basin, and this information is presented for completeness. 11.6.1 Legal framework The Mozambican Water Law passed in 1991, is the most important legal instrument in water related activities. This law brought about tangible changes in the institutional set-up of the water sector, allowing private sector participation in water projects. For example establishment of ARA’s and privatisation of state drilling companies. In relation to urban water supply, 5 of the major water supply systems are privatised. Two of these are relying on groundwater sources and Maputo planning to increase its water production through a wellfield. The new Water Law indicates the need to establish protection zones against mining and pollution, creating real tools for groundwater protection. Besides the Water Law there are some other laws affecting groundwater management, one of them is the Environment Law 20/97 and its supporting Decree Law regulating the EIA processes 96/98. The other important sector law is the Law of Land 19/97.



In 1995 a National Water Policy was also launched which contains the governmental strategy to increase the access clean water. For example definition of forbidden activities in protected zones is implemented using the Law of Land. The Water Law does not discuss in specific aspect related to groundwater utilisation instead those are left for further regulation by Decrees and other legal supplements (Water Law chap. VI art. 62). Very recently was passed the Ministerial Diploma for contractors, which request registration for all contractors and professional active in the field of groundwater including consultants. It is not yet clear how will it be monitored. 11.6.2 Established standards and procedures for groundwater development Perhaps, due to former Institutional set up, there are not official standards for groundwater development projects in Mozambique. Before (1992) opening up of water sector for private sector participation, groundwater projects were implement by DNA through its departments DAR and DGRH using internal guideline that where allowed consistent. Unfortunately these guidelines where never published as official documents for groundwater development and exploration. Few professionals, with access to this internal guidelines use it in their projects. The following are the documents used by DNA in its projects: 1. Critérios para Construção de Furos a Serem Equipados com Bombas Manuais em

Moçambique, DGRH 1997. “criteria for construction of boreholes to be equipped with hand pumps in Mozambique, 1997”

2. Guião de Fiscalização para Construção de Furos, DGRH 1998

“Guide for Supervision of Boreholes Construction, DGRH 1998” Following intensive research and experience elsewhere AFRIDEV was established as an official standard hand pump for wells with dynamic water level not deeper than 45-50 meters. Due to lack of consensus no official standardised hand pump exist for dynamic water levels greater then 50 m, however Volant is often used and sometimes Bush Pump is considered in these areas neighbouring to Zimbabwe following experience in that country. 11.6.3 Institutional framework Until recently the Ministry of Public Works and Housing (MOPH) through its National Directorate for Water Affairs (DNA) was responsible for water resource assessment, planning, development and management. The Mozambican water law approved and under implementation since 1991, brought significant changes and shifting of responsibilities. New regional authorities are being established in order to remain responsible for water resources management in some catchment. The MOPH is changing from being an executive to regulator, manager and policy maker. National Directorate for Water Affairs is co-ordinating all action related to the water sector in Mozambique. It is divided in departments with specific tasks namely: • Department of Water Resources Management (DGRH) divided in two sections one called

Geohydrology Section (SdG) and Hydrology Section (for surface water). • The Department of Urban Water Supply and Sanitation (DASU) which is responsible for

urban water supply and sanitation. • Department of Rural Water (DAR), until recently was called National Programme for

Rural Water. This department works more as a National Directorate for rural water programs. It is responsible for all issues related to rural water projects.

• Cabinet of International Rivers (GRI) to liaison with institutions in Neighbour countries



sharing the same river courses. At national level the DGRH and DAR are key institutions for groundwater resources assessment, development, exploration and Management in Mozambique. However, it should be indicated that this is only valid for rural groundwater supply. In case of Urban, Agriculture or other uses of groundwater, there are no clear indication on whose responsibilities is to regulate or facilitate. Therefore the responsibilities are defused to other Governmental institutions such as the Ministry of Natural Resources and Energy (MIREN) through its National Directorate of Geology (DNG), Ministry for Agriculture and Rural Development (MADER) and Ministry for Environmental Co-ordination (MICOA). In general DAR, is the only department with clear responsibility in groundwater sector, which remains responsible for all activities in rural areas for water supply. SdG is in the process of changing from operational section to facilitator, manager, policy making and groundwater regulator in general. The idea is to increase and upgrade the groundwater database and to implement more studies for investment in groundwater sector including definition of protection zones . Majority of groundwater development and exploration for urban and rural is carried out by DNA through its departments DAR and DASU following national development plans of the country drafted by the Government. In other cases, non-governmental organisations or international organisations working directly with local authorities submit, groundwater development plan, for approval by DAR. In a few cases, local government implements projects using their annual budget. SdG-DGRH, is currently seldom involved in groundwater development and exploration projects. In a few cases DASU and DAR request the services of SdG for supervision or field investigation in their projects. Many projects are implemented using private consultants with little intervention of SdG. SdG is now fully involved in Database management and drafting regulatory documents for groundwater development project and regulation. SdG is still in a transitory situation therefore, not yet active in management task neither in operative actions. The current trend is to outsource groundwater development project to private national/international consultants and contracting firms whenever enough resources are available. UNICEF and CARE-International are the major partners in groundwater sector in Mozambique; UNICEF supported and continues to support the government in the process of structuring its groundwater sector. Some other External Support Agencies active in the sector are the Japanese International Co-operation Agency, GTZ, HELVETAS – Sweden, SIDA, OXFAM, German Bank etc.



12. PILOT STUDY AREA(S) 12.1 Purpose of Pilot Study Area(s) An objective of the consultancy, and more specifically during the initial phase of the project, is to identify potential areas that are suitable for conducting more detailed geohydrological, social and groundwater management studies on a pilot scale. This information will then be applied in the development of drought mitigation protocols. The main purpose of conducting further studies on a selected and smaller area is three fold: • to investigate, demonstrate and promote on the ground the optimal use of groundwater

resources; • engage key stakeholders in a drought prone area to help optimize methods that will

secure water supply for human needs; and • in utilising the groundwater resource, to ensure that local ecosystems are not negatively

impacted upon. The pilot scale study (or studies) will assist in designing strategies that demonstrate the use and role of groundwater in pro-active drought mitigation and the implementation of measures based on groundwater resources as an alternative and reliable source of water during periods of extended drought. In addition, a comprehensive groundwater management strategy for the area will be formulated. The methodologies or set of guidelines for how such studies can be planned and implemented in other geohydrological and social environments within SADC countries will be used during the larger follow-up GEF project to identify suitable pilot scale sites for further study within the wider SADC region. Eventually the results from these studies can then be used to develop individual groundwater based drought mitigation strategies for each country or drought prone catchments. In addition, in the case of international (or shared) river basins, these strategies can form the kernel of coherent, integrated basin-wide strategies for integrated water resource management that would involve all the basin states concerned. In this section the criteria used in the identification and selection of the pilot study sites are presented. The initially identified areas were first scrutinized against these criteria to enable a prioritised list of pilot study sites to be compiled. This list was then discussed and reviewed by representatives from the four riparian countries during a workshop held in Gaberone, Botswana during March 2003. The representatives of the four riparian countries recommended that two pilot study areas should be used in the follow-up phase of this consultancy, as well as for the extended GEF project. Some additional geohydrological, social and groundwater management related studies were then conducted in these areas by short field visits. The outcome of these studies was presented to a Limpopo Stakeholder Workshop held in Johannesburg during May 2003. The purpose of the pilot component of the full GEF project will be to test the suitability and applicability of various groundwater management options to reduce population and ecosystem vulnerability to drought. 12.2. Selection Criteria In the initial selection of the Limpopo Basin as a study area for this project, the SADC representatives used some criteria that could equally well be used for the selection of pilot study areas within the basin. These criteria included characteristics such as multi-country involvement, drought prone area, environmental sensitivity, good knowledge of the geology (as this will be the basis for understanding the hydrogeology), benefit to the population, and others.



Not all regions within the Limpopo River Basin are equally prone to the impacts of drought. The southern and southeastern parts (Johannesburg, Pretoria, Rustenburg, Polokwane, Middelburg and Lydenburg regions in South Africa) are much less vulnerable, mainly due to the presence of a well developed infrastructure with access to backup surface water supplies during drought periods. Such areas were not considered as pilot study areas in this project. It was not possible to identify pilot study areas that conformed to all or most of the criteria set as none of the potential sites met all of these characteristics. Nevertheless, a list of possible pilot study areas was compiled and presented to the Limpopo Basin country representatives for a final decision. In compiling the list, each of the proposed areas was provisionally evaluated by the project team against the criteria set and a provisional prioritisation was presented to the delegates at the workshop. The outcome of the evaluation process is presented in Table 12.1. Based on the outcome of group discussions at a workshop organised by SADC in March 2002 in Pretoria, South Africa, and supplemented by subsequent discussions by the project team members, the following criteria were used in the evaluation:

• Representivity and replicability throughout SADC countries with regard to: o Geology o Hydrogeology (e.g. aquifer types and characteristics, sustainability) o Water and Land use o Potential Groundwater Dependent Ecosystems (GDEs) o Social-Political aspects

• Drought-prone area (climatic drought) and drought vulnerable aquifers. • Area should be environmentally sensitive (i.e. Impact of abstraction on biodiversity,

including cumulative and/or downstream effects) • Aquifer with competition between water users or user groups (i.e. community water

supply, commercial and subsistence farming, environment, etc). • Transboundary/shared resource involving at least two countries (including

downstream /cumulative impacts). • Knowledge and data availability (e.g. geohydrology, water-use and need,

groundwater dependence) • Consideration should be given whether area has a potential for developing a water

management framework • Water-use predominantly rural with possible agricultural groundwater use. • When determining size of the pilot study area, hydrogeological units should be taken

into account, not only sub-catchments. As a guideline 10 000 km2 (~100 km x 100 km) was suggested as a maximum size.

• Priority rating in SADC WSCU groundwater management programme. • Local and provincial or district water management structures and institutional

frameworks should be in place.

In terms of commitment to Integrated Water Resource Management (IWRM) and groundwater management in particular, it is believed that Government structures (National, Provincial or Local) are of primary importance. Since the provision of water resources to communities will be the primary responsibility of these structures and not solely that of the community, these were not used in the selection of pilot study sites. 12.3 Ecological Criteria A set of ecological criteria to address questions of representivity in terms of ecoregions and importance for biodiversity conservation (e.g. ecosystem functioning, uniqueness, irreplaceability) was not available during the selection process. Unfortunately, whilst it was



not possible to rate these criteria objectively with the sparse data available, there were also other considerations; for example, the fact that ecoregions and similar types of classifications are based on the extensive dryland vegetation types that are often located away from rivers. The vegetation types associated with floodplains, areas of groundwater discharge such as springs, and shallow water tables, often differ significantly from the adjacent dryland type. The sparse information on these vegetation types has been summarised in section 8. In the absence of adequate information on groundwater occurrences, depths and discharges, it was attempted to interpret the ecological criteria in Table 12.1 based on the geohydrological settings and the likely occurrence of GDEs. Therefore a dolomitic setting was rated as important because of the occurrence of cave and solution cavity systems which may support diverse and unique fauna. Another example is the extensive alluvial systems along the Limpopo and its tributaries where there is a high probability of groundwater dependent ecosystems. In most cases our knowledge of the importance for biodiversity conservation is inadequate but there are some of the proposed pilot study areas, such as Site 6 where floodplain wetlands are being considered for proclamation under the Ramsar Convention. The criterion of data availability has been rated purely form the ecological point of view. 12.4 Potential Pilot Study Areas and Motivations This selection of sites was based on as many as possible of the listed criteria. These sites were then evaluated and subjected to a subjective rating procedure according to the matrix shown in Table 12.1. The list of sites selected with a brief discussion on each site, starting from the headwaters of the Limpopo, moving towards the coast. The approximate positions of these sites are indicated on Figure 12.1. The size of the areas indicated on the map, is not representative of the area proposed for the pilot study, but merely provides an indication of the position in terms of the geohydrological conditions. Site 1: Dolomite and karstic aquifer conditions In the southwestern corner of the Limpopo basin (Botswana and South Africa) outcrops and suboutcrops of the Malmani dolomite formation are present and straddle the border between Botswana and South Africa. The Malmani formation hosts a major and strategic aquifer in the southern part of the basin and this transboundary occurrence has the potential to be developed into a major source of water for the region. This aquifer is shared by Botswana and South Africa. On the Botswana side there are indications of elevated concentrations of nitrate presumably due to human habitation. On the South African side a number of rural communities obtain their water supply from this aquifer, for example at Dinokana. Site 2: Fractured volcanic and sedimentary Site 2 is represented by superimposed Karoo-on-Waterberg/Palapye deep fractured sedimentary rocks south of Mahalapye along the Palala-Zoetfontein shear/fault system. This fault system is seismically active and some of the major hot springs in South Africa farther west in the Soutpansberg extensions are located in this tectonically active area. The Waterberg/Palapye outcrops are flanked to the north by a Karoo sedimentary succession with a potential for sustainable groundwater development. The Palla Road well field in Botswana is developed in this transboundary aquifer shared by South Africa and Botswana. Apart from relatively localized exploitation in the Palla Road well field development, this aquifer has not been extensively explored to date.



Site 3: Fractured volcanic and sedimentary on Basement Complex Further downstream along the Limpopo River, outcrops and suboutcrops of Karoo, Waterberg, and Palapye formations occur around Palapye in Botswana. These are underlain by Basement Complex granites that straddle the Botswana/South African border. The fractured Karoo sedimentary and volcanic succession and the underlying Waterberg and Palapye Groups and basement granite, both of which may have potential as fractured aquifers, are the targets. This can be regarded as a general example of fractured sedimentary rocks overlying Basement Complex rocks. Site 4: Karoo on Basement Complex A large Karoo basin is present in the Achaean basement terrain at the RSA-Botswana-Zimbabwe junction around the confluence of the Shashe and Limpopo Rivers. This basin is also referred to as the Tuli Trough (van Biljon and Legg, 1983; Barton, 1983) or the Tuli Basin (Smith, 1984). Drilling in Botswana has shown that Lebung Group sandstones, underlying basalt, have considerable groundwater potential and appear to be actively recharged. Given the presence of this basin in extensive basement areas where groundwater potential is generally poor, its potential as an important and strategic resource seems clear, particularly during drought periods. In addition the impact of the Limpopo and Shashe rivers with the associated alluvial fill river channels, and the palaeo-Moutloutse alluvials on the recharge to deeper aquifers is important. It would appear that at present only limited groundwater development of the basin has been undertaken on either side of the borders, making it an opportune time to conduct a tri-lateral study to determine baseline conditions and better quantify the aquifer’s true potential, especially during periods of extended drought. This hydrogeological condition (fractured sandstone underlying Karoo volcanics) is replicated at several sites within the Limpopo Basin and further north. Site 5: Fractured Basement Complex Regionally extensive outcrops of Basement Complex gneiss and granite straddle the Botswana / South African and Botswana / Zimbabwe border east of Palapye and north of Selibe Pikwe respectively. Large portions of these areas in Zimbabwe, South Africa and Botswana are populated by rural communities. In addition, several large areas also populated by rural communities in especially Zimbabwe and South Africa, are underlain by similar geology. Examples of such areas are the Limpopo basin in Zimbabwe (>70%), the Limpopo Mobile Belt outcrops to the west and east of Polokwane and Giyani, the acid rocks of the Bushveld Complex (Nebo, Verena), and the Makoppa Dome area west of Thabazimbi. Because of a general lack of surface water resources and low rainfall in these areas, these communities often have to rely on groundwater resources which have to date not been well explored and studied. Site 6: Fractured sedimentary In terms of geological and hydrogeological conditions, there are many similarities between Site 4 and Site 6. This site, similar to Site 4, also covers three countries; Mozambique, Zimbabwe and South Africa. On the Mozambique side large areas are covered by younger sedimentary formations. The area also lies within part of the giant Okavango dyke system (Hartnady, 2002) and part of the new Greater Limpopo Transfrontier Conservation Park (GLTCP) is within the proposed boundaries of Site 6. The inclusion of the GLTCP is a potential benefit to the local population in terms of socio-economic benefits and also has eco-environmental and tourism significance.



Site 7: Younger Coastal plain type deposits The central plains between the Changane and Limpopo Rivers in Mozambique are reportedly underlain by deep (>100 m) relatively fresh aquifers, despite being overlain by aquifers containing saline groundwater. This area is situated in the Mazenga proto rift zone to the east of the Urrongo Plateau. Totally different geohydrological conditions are present in this area. Unfortunately, the geological and geohydrological conditions of this area are not duplicated in other countries of the Limpopo Basin (but do occur in other parts of SADC) nor do the conditions extend into any of the other three riparian countries. Site 8: Alluvial deposits Over the entire Limpopo basin many non-perennial river courses occur. These often have deep erosion channels over sections of the river filled with coarse gravel, as well as alluvial covered plains alongside the river course. The best example of such a river is the Limpopo. The alluvium associated with these river courses forms high yielding aquifers that are normally recharged during every rainfall season. If the hydrogeological characteristics of these aquifers are well mapped and understood, coupled with proper management, these can provide sustainable sources of water during longer periods of low rainfall. It was proposed that one of these systems be selected as a study site. Possible sites for consideration are located (1) along the Botswana / South Africa border where it is associated with the Limpopo River, and has not been exploited properly to date, and (2) the Limpopo River where it forms the border between South Africa and Zimbabwe. 12.5 Selection of Pilot Sites For prioritising these eight proposed sites, each site was evaluated against the main criteria and a scored according to a 3-point system. Points have been allocated according to the following scheme: Complied to the tested criterion 3 points Not sure whether it complies (mainly due to a lack of information) 2 points Does not comply to the tested criterion 1 point The outcome, with the priorities listed at the bottom of the table, is presented in Table 12.1 was presented to the Steering Committee meeting in Gaberone for discussions and debate. 12.6 Final Selection of Pilot Study Areas At the first Steering Committee Meeting of the Project “ Protection and Strategic uses of Groundwater Resources in the Transboundary Limpopo Basin and the Drought Prone Areas of the SADC Region” held in Gaborone, Botswana on 11-12 March 2003, the information described in the preceding chapters of this report were presented to the SADC country representatives attending the meeting. One of the aims of the meeting was to select a suitable pilot study area or areas based on the information presented to the delegates attending the meeting. The presentation was followed by a session during which the motivations and arguments for and against each site were thoroughly debated. In the end Sites 4 and 6 were identified as the preferred sites for future pilot scale studies. For convenience these two sites will be referred to as the Western and Eastern Pilot Study Areas in the remainder of this report. The exact boundaries of these two sites were not determined at the Gaberone meeting, and it was left to the project team to finalise the boundaries based field visits, discussions with stakeholders and the outcome of the stakeholder workshop.



Figure 12.1: Proposed pilot study sites. For an explanation of the numbers, refer to text.

-- Major rivers o Pilot Sites A lluv ium · Re<;ent Coastal sands - Rm::ent Coastal sand s - semi-cons fractured seds

_ Fractured basa~ _ Fractured basa~·rtlyol ite _ Fractured qual1zrtes. quartzrtes. sandstone and shale

Fractured quartzites, sandstone and shale _ Limestone, dolomite _ Fractured crystal line basement (felsic) _ Fractured crystalline basement (mafic-felslc) _ Fractured metavolcanics . quartzites, sandstone and shale (metamorph osed)

Fractured crystal line basement (malic) Fractured crystalline basement (fels~) ami weathered basement

_ Fractured metasedimenta basement (Malic-felsic)

25 CTlI"E

Pilot sites

300'O' E

. " . I I

, " ,

• • , ,. • • , .'

, "'0 ____ i , "



Table 12.1: Site evaluation matrix

Site 1 Site 2 Site 3 Site 4 Site 5 Site 6 Site 7 Site 8

Category Criterion Y/ U/ N

Score Y/ U/ N

Score Y/ U/ N

Score Y/ U/ N

Score Y/ U/ N

Score Y/ U/ N

Score Y/ U /N

Score Y/ U /N

Score

Replicability • Hydrogeology • Land use • GDE

Y U Y

3 2 3

U U Y

2 2 2

U U Y

2 2 2

U Y Y

2 3 3

U Y-U N

2 2.5 1

U Y Y

2 3 3

U Y Y

2 3 3

U Y Y

2 3 3

Drought prone Y 3 Y 3 Y 3 Y 3 Y-N 2.5 Y 3 U 2 Y 3

Impact on bio-diversity U 2 U 2 U 2 Y 3 U 2 Y 3 U 2 Y 3

Shared resource Y 3 Y 3 Y 3 Y 3 Y-N 2 Y 3 N 1 Y 3

Bio

-ph

ysic

al

Data availability U 2 U 2 U 2 Y? 2.5 Y-N 2 Y 3 U 2 Y? 2.5

User demand Y 3 Y 3 Y 3 Y 3 Y 3 Y 3 U 2 Y 3

Water use Y 3 Y 3 Y 3 Y 3 Y 3 U 2 U 2 Y 3

So

cio

-p

olit

ical

Socio-economical U 2 U 2 U 2 U 2 Y 3 U 2 U 2 Y 3

Score 18 24 24 27.5 23 27 21 28.5 Prioritization of sites according to score: High Site 8 Y = Complied to the tested criterion (3 points)

Site 4 U = Not sure whether it complies (mainly due to a lack of information) (2 points) Site 6 N = Does not comply to the tested criterion (1 point) Site 1 Site 2 Site 3 Site 5

Low Site 7 The four sites with the highest score are shown as bold and are shaded.



Guidelines used in the final determination of the boundaries included: • Size of each area to be of the order of 10 000 to 15 000 km2 • Approximately equal country surface areas in each Pilot Study Area • Areas to have a representative mix of different land and water users and water

demand patterns. In Figure 12.2 the outlines of the two areas, relative to the entire Limpopo River Basin, are shown. Brief visits to the two Pilot Study Areas were made by members of the project team in preparation of a planned Stakeholder Workshop. The objectives of these visits were to gather additional information on the two areas, especially with reference to the socio-economic conditions in each area, and to identify a representative group of potential stakeholders to be invited to the Stakeholder Workshop. Brief visits were made to the two Pilot Study Areas by members of the project team in preparation of a planned Stakeholder Workshop. The objectives of these visits were to gather additional information on the two areas, especially with reference to the socio-economic conditions in each area, and to identify a representative group of potential stakeholders to be invited to the Stakeholder Workshop.

Figure 12.2: The position of the two selected Pilot Study Areas along the Limpopo River



13. DESCRIPTION OF THE TWO SELECTED PILOT STUDY AREAS 13.1 Western Pilot Study Area 13.1.1 Physiography, drainage and climate The elevation of the study area varies between approximately 1 050 mamsl in the northeastern side of the study area, and approximately 450 mamsl being the lowest point on the Limpopo river where it leaves the area (Figure 13.1). The topography is gently undulating with the most prominent topographic features occurring in the Limpopo valley where ridges are formed by outcrops of the Karoo sandstone. The highest areas are formed y outcrops of the Karoo basalt. The Limpopo River forms the international boundary between South Africa in the south, Botswana in the west and Zimbabwe in the north. The highest lying parts of the WPA occur in Botswana and Zimbabwe with the high Soutpansberg Mountains in South Africa situated to the south. There are significant alluvial deposits in the lower Motloutse and Shashe Rivers and in the section of the Limpopo between the Motloutse confluence and the eastern boundary of the WPA.

Figure 13.1: Physiography of the Western Pilot Study Area showing the major rivers and towns.

The Shashe and Limpopo rivers are the most prominent drainage features with the Thune and Motloutse Rivers in Botswana draining into the Limpopo and the Tuli and Umzingwani Rivers in Zimbabwe draining into the Shashe and Limpopo Rivers respectively. No large rivers drain the South African side of the study area. All rivers in the area are classified as ephemeral. In the study areas the gradients of the Limpopo and Shashe Rivers are approximately 1:600 and 1:800 respectively. Both the Motloutse and Shahse Rivers contribute significantly to the flow in the Limpopo main stem and to the shared alluvial aquifer



(Boroto and Görgens 1999, 2001). The area experiences warm summers and cool dry winters. Temperatures typically reach >40°C in summer in the Limpopo valley. The average annual rainfall varies between 250 mm and 500 mm with the majority of the rain occurring in summer between the months of October to April (Figure 13.2). The low rainfall in much of the South African section is because this portion falls in the rain-shadow of the Soutpansberg range. The mean annual potential evaporation is very high (1 450-1 500 mm) in the central portion of the area, decreasing slightly in southern Zimbabwe. Most of the WPA is classified as semi-arid.

Figure 13.2: Distribution of mean annual rainfall (MAP) for the Western Pilot Study Area. 13.1.2 Land cover and land-use Most of the WPA is classified as bushland, a roughly 50:50 mixture of woody species (trees and shrubs of varying heights) and grasses (Figure 13.3). Woodlands which have a higher cover of taller woody species occur in the northern parts of the WPA in Zimbabwe. The vegetation on the basalts is classified as the Zambezian and Mopane woodlands. Over the rest of the WPA the vegetation is classified as Southern Africa bushveld, characterized by a mixture of mopane and Combreturm but quite species-rich, with other genera such as Commiphora and Terminalia and extensive areas, particularly on the Karoo sandstones, where baobabs are prominent. There are substantial areas of cultivated land on the southern side of the Limpopo in South Africa. The land cover classification does not show the azonal vegetation types. The most important of these are the floodplain forest and woodland types, which are particularly prominent on the floodplains of the Limpopo and its major tributaries. The forests on the river banks themselves are important as a habit and refuge for many other species.



Figure 13.3: A land cover classification of the Western Pilot Study Area. Data from the classification

being developed for the SADC by the CSIR. A section of the area has not been mapped yet, the boundary between the woodland and bushveld classes will follow the northern boundary of the shown

in the geological map.. In Zimbabwe large areas of land are classified as communal land with a low density rural population. Some land closer to Beit Bridge and the Limpopo River is set aside for large scale commercial farming, whereas two areas bordering on the Mzingwane River in the east of the study area are classified as Model A & D Resettlement areas. Two large commercial farming areas along the Limpopo River, known as Nottingham and Sentinel Ranches, were noted during the field. To the west of the Thuli River a large area, known as the Tuli Safari area is set aside for controlled hunting. Some government developed irrigation schemes utilizing groundwater from the alluvial aquifers associated with the Thuli, Shashe and Umzingwane Rivers have been developed. These are the Shashe, Bili Jarukanga and Kwala Irrigation schemes, which together cover an area of some 260 ha. In the areas demarcated as Communal Land, subsistence farming (stock and crops) is practised on a small scale. The part of the study area in Botswana is almost exclusively used for stock farming, with small areas where crops are cultivated on a small scale for subsistence farming. As is the case in Zimbabwe, some irrigation farming takes place along the banks of the Limpopo River in an area referred to as the Tuli Block. In the eastern corner of the study area in Botswana the triangle formed at the confluence of the Shashe and Limpopo Rivers, is a declared Nature Reserve known as Northern Tuli Conservation area or Mashutu Reserve. The part of the study area in South Africa is characterized by commercial game and stock farming, and large areas are set aside as Nature and Game Reserves (i.e. Vhembe, Venetia Limpopo and Kimburger) or Conservancy areas. At several areas along the Limpopo River large commercial farms (notably at Weipe just downstream of the Shashe/Limpopo confluence) using groundwater from the alluvial aquifers along the Limpopo River have been



developed. The Venetia diamond mine, situated in the Venetia Limpopo Nature Reserve, extracts large quantities of water from the alluvial aquifer of the Limpopo River on the farms Greefswald and Schroda for its operation. 13.1.3 Population distribution The population densities are low throughout the area with less than 25 people per hectare and less than 5 in Botswana (Figure 13.4). The people are not distributed evenly and there are population concentrations in the vicinity of the main towns shown on the maps. In South Africa most of the land is under commercial agriculture or game farming and the people are concentrated in small farm settlements. The workers at the Venetia Mine are bussed in from Messina each day and only a few staff live permanently at the mine.

Figure 13.4: Population distribution for the Western Pilot Study Area. 13.1.4 Geological description From a geohydrological perspective, three geological “groupings” are of importance in this study area (Figure 13.5). These are the:

a) archaean mainly gneissic rocks of the Limpopo Mobile Belt, b) sedimentary and volcanic rocks of Karoo age, and c) Quaternary alluvial deposits associated with the main rivers cutting through the

area. The dominant geological feature in the study area is the lenticular shaped Tuli Trough (Barton, 1983), also referred to as the Tuli Basin, (Smith, 1984), in the centre of the area.



This trough is filled with sedimentary formations of Karoo age (~300-150 Ma) deposited unconformably on the metamorphosed and highly distorted gneiss of the Central zone of the Archaean Limpopo Mobile Belt (Van Biljon and Legg, 1983). The sedimentary formations are capped with a thick layer of basalt, also of Karoo age. All along the edge of the basalt, and especially the southern and western sides, outcrops of the sedimentary sequence flank the basalt. The northern edge of the trough is formed by an ENE normal fault, with gneiss of the Northern Marginal Zone of the Limpopo Mobile Belt on the northern side of the fault. The southern, western and eastern edges for the Tuli Basin are formed by gneiss of the Central Zone of the Limpopo Mobile belt.

Figure 13.5: Geological map for the Western Pilot Study Area. Substantial thicknesses and volumes of alluvial deposits are associated with the two main rivers, the Shashe and Limpopo that drain the area. The geological structure is dominated by ENE directed faults and dykes in both the Archaean and Karoo age formations. The rocks of the Limpopo Mobile Belt are intensely folded and metamorphosed. A second prominent structural direction is that of the ESE trending dykes of the Okavango Dyke Swarm (Botswana Department of Geological Survey, 1999), which intruded shortly before the break-up of the Gondwanaland supercontinent (Hartnady, 2003). 13.1.5 Geohydrological considerations Initially and during times when the water demand was still relatively low, the fractured basalt was the main drilling target. Borehole yields from this aquifer are generally low (<2 l/s) compared to that from the underlying sandstone aquifers, and the Total Dissolved Solids (TDS), are often found to be in excess of 1 000 mg/l. In addition this aquifer is more vulnerable to pollution as has been shown by boreholes in and around Bobonong which had



to be abandoned as production boreholes due to pollution. As a result, attention has lately shifted towards the underlying Tsheung sandstone aquifer. As a result of intensive faulting within the Tuli Basin, giving rise to graben and horst structures, the depth to the top of the sandstone varies over short distances and can be in excess of 400 m in places. However, yields are significantly higher than in the basalt and the quality is in general also better. The best water strikes are normally encountered at the fractured zone just below the contact with the overlying basalt, but continually increasing yields are observed with deeper penetration into the sandstone. This suggests either additional fracturing of the sandstone (horizontal or bedding plane or inclined), coupled with perhaps some primary porosity, in the sandstone formation.

Figure 13.6: Groundwater levels shown as depth below surface in the Western Pilot Study Area. Only borehole data were available for Botswana and South Africa.

As a result of the experience gained from extensive groundwater exploration conducted in Botswana, it is likely that similar conditions are present in other parts of the Tuli Basin, especially Zimbabwe, and to a lesser extent in South Africa, where the deeper sandstone aquifer has not been exploited to the same degree. In South Africa, high borehole yields are observed at relatively shallow depths in fractured basalt. These occur along the Taaibosch fault and it is perceived that the fracturing is related to the faulting. Extensive research is currently underway to understand the geohydrological conditions associated with the Taaibosch fault. The Archaean gneiss terrain generally produces low yielding boreholes and exhibits a poor historical success rate with less than 40% of boreholes yielding less than 0.1 l/s. A recent study by Sami et al (2002) where two areas underlain by rocks of the Limpopo Mobile Belt (LMB), indicates that although the majority of boreholes are low yielding, high yielding targets (up to 18 l/s) do exist. An analysis of hydrocensus information indicates that the occurrence and movement of groundwater in the Archaean rocks is mainly controlled by the prevalence



and orientation of secondary features such as faults, joints and fracture zones (Sami et al, 2002). As such not much attention has been given to understand geohydrological conditions in these geological environments. However, as large areas within the Limpopo Basin are underlain by these rock types, and because these areas host mostly rural communities dependant on groundwater for their water supply, it is imperative that more attention should be given to these areas to understand the geohydrological conditions better. This knowledge is also required to define groundwater management guidelines to ensure a sustainable water supply during the extensive and often prolonged periods of drought experienced in these regions. From the experiences to date, it is therefore concluded that the two most prominent aquifers in this pilot study area would be the alluvial deposits associated with the Shashe and Limpopo Rivers, and the confined fractured sandstone aquifer underlying the basalt in the Tuli Basin. In Botswana the sandstone aquifer has been the target of geohydrological investigations to locate sustainable water resources for towns and villages in the region. The villages of Bobonong, Gobojango, Semolale, Tsetsebjwe, Pont Drif, Mathatane, Motlalatau, Mabolwe, Lepokole in Botswana are totally dependant on groundwater for their water supply. 13.2 Eastern Pilot Study Area 13.2.1 Physiography, drainage and climate The eastern pilot area (EPA) is centred roughly on the intersection of the borders of Mozambique, South Africa and Zimbabwe (Figure 13.7). Major tributaries include the Bubye from Zimbabwe, Luvuvhu from South Africa and Munezi from Zimbabwe via Mozambique. All make substantial contributions to flow in the middle and lower Limpopo. The Levuvhu River maintained quite a strong perennial flow regime until the early 1990’s when over-abstraction for irrigation in the upper reaches and droughts caused the river to become seasonal. The topography of the EPA is also generally fairly flat to gently undulating, rising northwards towards the escarpment in Zimbabwe and the eastern Soutpansberg in South Africa. The northern end of the Lebombo mountains crosses the area, roughly following the South Africa - Mozambique and the Zimbabwe - Mozambique borders. There are extensive alluvial floodplain deposits along the Limpopo, beginning about 20 km upstream of the Levuvhu confluence and extending into Mozambique. The EPA generally has a higher rainfall than the WPA, with only a small part in South Africa having 250-300 mm per year and fairly large areas with more than 450 mm (Figure 13.8). A small portion of the Soutpansberg in South Africa receives more than 500 mm. Most of the EPA has a mean annual potential evaporation of 1 450-1 500 mm per year, the maximum being 1 500-1 550 in Mozambique in the northeastern part. The aridity index for the EPA is 0.30-0.40 over much of the catchment, reaching 0.20-0.30 in the low-lying areas central part of the Limpopo valley in the western part and in Mozambique. Much of the EPA is classified as woodland vegetation, especially on the Lebombo basalts, interspersed with bushland (Figure 13.9). Grassland areas occur in the northwestern and northern parts of the Mozambican part of the EPA. The vegetation of the EPA includes a large area of Zambesian and Mopane woodlands, which range from open sparse savanna (less than 5 m tall) to tall dense woodland. In many areas the mopane dominates and almost excludes any other woody species but in other areas the diversity is quite high. Drakensberg montane grasslands, woodlands and forests are found in the eastern Soutpansberg in South Africa. Southern Africa bushveld occurs between the previous two vegetation types and extends eastwards along the Zimbabwean escarpment. Cultivated land occurs as scattered patches throughout the EPA except in the former hunting areas of Mozambique and the



Kruger National Park in South Africa. The classification does not show azonal vegetation types.

Figure 13.7: Physiographic map of the eastern pilot area showing the international

boundaries, major rivers and towns.

Figure 13.8: Distribution of mean annual rainfall in the eastern pilot area.



13.2.2 Land cover and land-use The most extensive and important of these are the floodplain forest and woodland types, which are particularly prominent on the floodplains of the Limpopo and Levuvhu Rivers. The forests are important as a habit and refuge for many other species. Another distinctive type is the salt tolerant vegetation, which occurs where there is groundwater discharge originating in the patches of high salinity in the marine deposits in Mozambique. Populations in the Mozambican section are concentrated along the Limpopo Rivers where there are several small villages and a population of roughly 14 000 people between the border in the north and Mapai in the south.

Figure 13.9: A land cover classification of the eastern pilot area. Data from the classification being developed for the SADC by the CSIR.

The main land-uses in the South African and Zimbabwean sections of the EPA are extensive commercial farming, game ranching or communal lands, the latter being clearly seen in the extensive areas of bare ground and scattered dryland cultivation (for example the area south-west of Masisi). There are large areas of irrigated land in the Luvuvhu catchment but they fall mainly outside the boundaries of the Pilot Study Area. 13.2.3. Population distribution Population densities in the eastern area generally are substantially higher than those in the western one, with more than 25 people in the Sengwe area of Zimbabwe and as high as 100-500 per hectare in the former Venda homeland in South Africa (Figure 13.10). The major conservation areas in South Africa have very low population densities because the people were removed at the time the parks were established.



Figure 13.10: Population distribution for the Eastern Pilot Study Area. 13.2.4 Geological description The three geological features dominant in the Western Pilot Study area, also occur in the eastern study area (Figure 13.11). These are the Archaean gneisses of the Limpopo Mobile Belt, the sedimentary and basalt formations of the Karoo, and the alluvial deposits associated with the large rivers. The southern and eastern parts of this study area are however, totally different. The far northwestern section of the Study area in Zimbabwe is characterised by the gneissic rocks of the Central Zone of the Limpopo Mobile Belt whereas some gneisses of the Southern Marginal Zone of the Limpopo Mobile Belt outcrop along the south-central part of the study area. Towards the southern part of the study area, another major WNW -ESE trending sedimentary Soutpansberg Basin of Proterozoic age is present consisting of predominantly sandstone, shale, conglomerate and some basalt and tuff. Along the northern flank of the basin, Karoo age sandstone and basalt, similar to those of the Tuli Basin, occur. These Karoo age formations curve towards the south and occupy an approximately 20 km wide outcrop of basalt along the eastern border of South Africa with Mozambique. The basalt outcrops extend far into southeastern Zimbabwe towards Chiredzi and the Save River. A thin fringe of Karoo sandstone occurs all along the western and northeastern edge of the basalt. The eastern edge of the basalt forms the western boundary of the extensive and broad coastal plain along the Mozambique cost. Immediately to the east of the Lebombo Basalt, outcrops of Cretaceous sandstone and limestone occur, which are in turn covered by younger Tertiary and Quaternary sedimentary successions on either side of the Limpopo River. The dominant structural direction is, similar to that in the western pilot study area, ENE-WSW. The sedimentary formations dip towards the north and are vertically displaced by ENE trending faults. The most prominent faults are the Bospoort and Klein Tshipise faults.



These faults illustrate the Late Cenozoic neotectonic reactivation this area has experienced. Concurrent to this reactivation, a significant number of hot springs, of which the one at Tshipise (South Africa) is the most well known, and other geothermal phenomena along these structural directions were formed. The eastern edge of the basalt forms the western boundary of the extensive and broad coastal plain along the Mozambique cost. Immediately to the east of the Lebombo Basalt, outcrops of Cretaceous sandstone and limestone occur, which are in turn covered by younger Tertiary and Quaternary sedimentary successions on either side of the Limpopo River.

Figure 13.11: Geological map for the Eastern Pilot Study Area. The dominant structural direction is, similar to that in the western pilot study area, ENE-WSW. The sedimentary formations dip towards the north and are vertically displaced by ENE trending faults. The most prominent faults are the Bospoort and Klein Tshipise faults. These faults illustrate the Late Cenozoic neotectonic reactivation this area has experienced. Concurrent to this reactivation, a significant number of hot springs, of which the one at Tshipise (South Africa) is the most well known, and other geothermal phenomena along these structural directions were formed. From a geohydrological perspective, the Karoo age sedimentary rocks, the younger Cretaceous and Tertiary sediments in Zimbabwe and Mozambique, and the alluvial deposits associated with the major river courses (Limpopo, Levuvhu, Bubye and Nuanetsi, are the most important features in this study area.



13.2.5 Geohydrological considerations Only borehole data were available for South Africa and very limited data for Mozambique. Water levels near the Limpopo and Mwenezi (Nuanetzi) Rivers in Mozambique are likely to be shallow (as shown in Zimbabwe) but may be saline.

Figure 13.12: Groundwater levels shown as depth below surface in the Eastern Pilot Area. 13.3 Conservation Areas The proposed Limpopo-Shashe Transfrontier Conservation Area is centred on the Shashe Limpopo confluence (Figure 13.13). The core area for the South African part of the TFCA is based on the Vhembe Nature Reserve. The reserve has been taken over by the South African National Parks Board and is in the process of being expanded to form the Vhembe-Dongola National Park. The SANPB is busy developing tourist infrastructure in the park at present. To the south of this core area there are the Limpopo Valley Game Reserve and the Venetia Limpopo Nature Reserve. In Botswana the Northern Tuli Game Reserve is situated in the northwest corner of the Tuli Block, across the Limpopo from South Africa and across the Shashe from Zimbabwe. Zimbabwe currently does not have a conservation area except for the Tuli Circle Safari Area. Two farms on the northern side of the Limpopo River in Zimbabwe – Sentinel Ranch and Nottingham – may still be incorporated in the TFCA. In addition to creating a conservation area that spans the Limpopo River, the area includes the very important Mapungubwe site which dates from the African iron age period shortly after the Great Zimbabwe empire collapsed. The boundaries of the Maramani communal land, Sentinel Ranch and Nottingham in Zimbabwe are not shown on the map. These are all areas that could potentially form part of the Limpopo-Shashe transfrontier conservation area and they cover most of the Zimbabwean section of the pilot area.



Figure 13.13: Existing conservation areas in the western pilot area.

The Maramani communal land occupies a triangle of land between the Sentinel Ranch and the NTGR. In collaboration with the Italian Association for World Solidarity, CESVI (“Cooperezione e sviluppo”), the District Development Fund (DDF) are working on a programme to integrate communal land and areas in South Africa and Botswana set aside for nature reserves around the confluence of the Shashe and Limpopo rivers into a Trans Frontier Park (TFP). The Greater Limpopo TFCA is much further developed and already has entered the stage of negotiations around cross-border access. It includes three national parks, Gonarezhou in Zimbabwe, the recently proclaimed Limpopo in Mozambique and Kruger in South Africa (Figure 13.14). Negotiations for further expansions are underway, particularly the corridor that will link Gonarezhou and the Kruger. It also has a number of African Iron Age settlements, including Thulamila in the park and at Gumbu and Mabyeni in the Madimbo area to the west of the Kruger Park. 13.4 Groundwater-Dependent Ecosystems in the Pilot Areas 13.4.1 Introduction Based on the geohydrological information for the pilot areas, the GDEs in the two pilot areas can be classified into three main types:

• Shallow, localized regolith aquifers which are widespread; they have a limited amount of water storage; therefore discharge is likely to vary seasonally and be unreliable during droughts. They are too poorly known and understood to determine whether the GDEs are likely to be resilient and how strongly they may depend on groundwater.



Similarly, it is not clear whether these systems would potentially be important sources for groundwater supplies during droughts.

• Spring-type discharges associated with fault zones, major faults, fractures, dykes and sills, and contacts between rocks with different aquifer characteristics and permeabilities; the sensitivity of the GDEs will vary with the degree of storage and thus the reliability of the discharge; GDEs associated with major aquifer discharges will be strongly to entirely dependent on groundwater; some of these systems may be associated with discharges from confined aquifers; reliable discharge will be a factor favouring the development of such systems for groundwater supply during droughts.

• Floodplain systems with shallow unconfined aquifers which can be reached by the root systems of the trees in the woodlands and forests that typically develop on these floodplains; these systems are sustained mainly by recharge during periods when there is surface flow or flooding; lateral inflows will be a minor component except, potentially where groundwater may be discharging into the rivers (e.g. where fault zones cross them); these system have, historically, been very reliable groundwater sources and the vegetation is likely to be highly dependent on access to groundwater; changes in water levels relative to the historical fluctuations (e.g. due to abstraction for irrigation) may have a significant impact; the plants will be particularly sensitive to sudden and rapid drops in water levels; these systems already sustain economically important enterprises and are well suited to development for drought backup supply systems.

In the next section the floodplain GDEs are described in more detail as they are the most likely to be used for groundwater supplies during droughts.

Figure 13.14: Existing conservation areas in the eastern pilot area. The area shown as protected in Mozambique has been formally proclaimed as the Limpopo National Park.

There are also plans to establish a corridor between Gonarezhou and the Kruger National Park.



13.4.2 Floodplain groundwater dependent ecosystems The floodplain GDEs are important because they provide habitat for a wide range of fauna and flora (Gregory et al, 1991; Naiman et al. 1993; Clark and Samways 1996; Stewart and Samways 1998; State of the Rivers 2001) and also provide goods and services to rural communities. The fauna, notably the large herbivores, in turn, have an important role to play in modifying and regenerating these ecosystems and also in the dynamics of the floodplain environments (Naiman and Rodgers 1997). 13.4.2.1 Flow regimes There is a strong relationship between the cross-sectional structure of a floodplain and the flow regimes and flood stages (depths) in a river (Figure 13.15; Van Niekerk et al. 1995; King et al. 2000). During periods of low flow there may or may not be some flow on the surface of the main river bed (macro-channel) and groundwater flow will be downstream and potentially lateral. Annual floods will typically fill the river bed from bank to bank but will not overtop the main levees; there will probably be some lateral outflow from the river that will recharge the river banks and the floodplain aquifer depending on relative water levels and rates of percolation. High floods, for example a 1:50 year flood, will recharge the entire floodplain and well as severely disturbing the river vegetation. In addition to these fluxes there are also interchanges between the hyporhoeic zone1 and the surface water which alter biogeochemical processes, including nutrient cycling (Jones et al. 1996).

High terrace (rarely inundated)

Macro channel bank

Palaeo sediments

Terrace (infrequently inundated)

Active channel bank

Flood bench (inundated by ‘annual’ flood) Active channel

Flood plain (inundated by ‘annual’ flood)

Active channel bankBar Mid channel

bar

Low-flow channels

Modern sediments

Levee

Figure 13.15: Cross section of a typical alluvial river bed showing the main features and relationships

with different flow and flood levels (after King et al. 2000).

The ecology of the floodplain systems is also highly sensitive to the flow regimes in the river.

1 The portion of the saturated zone below the river bed in which there is interchange with surface waters; the portion with no interchange is called the groundwater zone (Jones et al. 1996).



The difference between a perennial and an episodic flow pattern is not just a matter of arbitrary division according to flow frequency distributions (Uys and O’Keeffe 1997). There are important biological transitions. Perennial rivers can sustain a variety of organisms that need permanent surface water to survive, for example fish species. Rivers with regular seasonal flow can sustain species which are able to survive the dry period in some way either within the river system or elsewhere. Episodic rivers can only sustain specialized organisms that can survive the extended and unpredictable dry periods. This applies to all the organisms whether they are adapted to survive in surface water, or in the hyporhoeic zone or in deeper layers, typically in anoxic conditions. Water is also the medium driving interchanges of oxygen, nutrients and other compounds between the surface and sub-surface systems and supporting complex ecosystems (Jones et al. 1996; Woessner 2000). 13.4.2.2 Vegetation patterns When seen in cross-section, the different sections of the floodplain of a major river may have different vegetation types (Van Coller et al. 1997; Rowntree et al. 2000). The vegetation on the riverbanks (levees) in the main channel may or may not support reed beds. Reeds rapidly colonise sediments as they are deposited, so depositional rivers will tend to accumulate reed beds. They also will tend to flourish during drought periods because of the low flows, and be scoured away during floods. The vegetation on the main rivers banks (levees) will have good access to water in most years and will typically develop into tall riparian forest (Figure 13.16) with species such as sycamore fig (Ficus sycomorus), nyala berry (Xanthocercis zambesiaca), jackal berry (Diospyros mespiliformis) and ana tree (Faidherbia albida). The remainder of the floodplain is less well watered and will tend to have a woodland community or palm savanna, typically with lala palms (Hyphaene species). The section shown here is from the Limpopo in Mozambique but is very similar to the situation in the western pilot area. No detailed studies could be located for the WPA but there have been several studies in the EPA (overviews given by Deacon 1998; Peace Parks Foundation 2000) and the vegetation is basically similar. Much of the floodplain vegetation in the WPA, at least in South Africa, has been degraded or severely disturbed, and the levee forest has been cut off from the adjacent terrestrial environments by agricultural developments. Thicket vegetation usually associated with drainage lines and termitaria account for about 15% of the Limpopo National Park (Peace Parks Foundation 2000). Characteristic tree species of riverbanks include those listed above plus Acacia robusta. Scrub thickets on sodic clays associated with the basalts on the floodplain margins include Azima tetracantha, Cordia sinensis, Acacia tortilis and Ximenia caffra. Fever tree (Acacia xanthophloea) woodlands occur in depression on cut-off meanders with leadwood (Combretum imberbe), Acacia tortilis and lala palm (Hyphaene benguellensis). Open mopaniveld is found on the older flood-plain surfaces, with Kirkia acuminata, Commiphora africana, Combretum hereroense and Terminalia prunioides. Forty nine species of fish are known from the area. Three species deserve special conservation status because of their rarity and limited distribution, these being the two small seasonal pan inhabitants Nothobranchius orthonotus and Nothobranchius rachovii, as well as the lungfish Protopterus annectens. Thirty four species of frogs are known from the area. The Sandveld Pyxie (Tomopterna krugerensis) was discovered within the Kruger Park and has its main area of distribution within the Transfrontier Park area, although it has also been recorded in Kwa-Zulu Natal, South Africa. A detailed overview of the floodplain and pan communities around the Limpopo-Levuvhu confluence is given by Deacon (1996) and it is clear that this area also supports a wide variety of species. The floodplain communities of this area are very similar to those described for the Limpopo NP with the addition of grasslands dominated by Sporobolus consimilis in the outer parts of the floodplain. The Madimbo section to the west of Kruger National Park also is a unique landscape with an accompanying wilderness character. The riverine



vegetation of this area includes two of the four most endangered plant communities in the Limpopo River system. The two remaining pans in this area Nyawadi/Banyini and Klein Pannetjie are important components. This area is also an historic migratory route for elephants and buffalo from Zimbabwe to the Transvaal Lowveld. The transborder floodplains are considered to be of international importance, particularly for breeding waterbirds, 38 species of fish and 33 species of amphibians. The floodplain forests also provide a habitat for eight species of bats, including Egyptian, Rüppels, Swinny’s horseshoe, the Madagascar large free-tailed and Commerson’s leaf-nosed bats. Other mammals include the Samango monkey, Nyala antelope, Suni antelope, Four toed elephant-shrew, woodland mouse and a range of bird species (Deacon 1996; Hurford et al.1996). An application for Ramsar status is being developed at present (A.R. Deacon personal communication 2003).

M o p a n e tree savanna on o lder f loodplain surface

Depress ion o f cu t-off meander . Woodland

of fever t rees, A. tort i l is, knobthorn ,

leadwood , Hyphaenebenguellaensis

Scrub -thicket on sodicclays of Salvadora

austral is , A z i m atetracantha , X imenia ,

Grewia , Cordia , Euphorb ia , Sanseviera

Levee or r iverbank zone. B ig t imber woodland and th icket e .g F icus

sycomorus, A. robusta , Xanthocerciszambesiaca, Diospyros mespi l i formis

L impopo River

Acacia tortilis

Thicket of s imb i t s i, Commiphora , Termina l ia

p run io ides, Stercu l ia, Phy l lan thus

Figure 13.16: A cross section of the Limpopo floodplain showing the different vegetation types and species associations. Original sketch drawn by Ken Tinley (redrawn from a figure in Peace Parks

Foundation 2000).

13.4.3 Preliminary Mapping of Groundwater Dependent Ecosystems The lack of time and resources for reconnaissance of the pilot study areas meant that an alternative approach had to be considered which made use of readily available data. One of these approaches is based on the fact that GDEs will typically have more lush vegetation than the surrounding areas. Therefore they should show up in aerial photographs or suitable satellite images depending on the resolution versus the detail or level of spatial resolution of the remotely sensed data. Although aerial photographs would be give the most detail, there was no time to collect and process them. Landsat images are relatively cheap and can be used to identify extensive systems, and generally the kind that would be likely to be used for groundwater supplies during drought. In dry environments like the pilot areas, GDEs are likely to differ from other vegetation in showing little change in their conditions from dry season to wet season. Images were obtained which covered most of the pilot areas and allowed fore a comparison of dry season and wet season conditions. Vigorous and actively growing vegetation can be highlighted by using the standard red, green and blue bands with the vegetation showing up strongly as the red colour on the floodplains, along streamlines and irrigated fields (Figures 13.17 and



13.18). The dark blue shades north of the Limpopo in the WPA are due to the dark, basalt-derived soils. In the WPA the most prominent vegetation is clearly the agricultural crops which are growing in the centre-pivot irrigated fields. Red bands can also be seen along most of the water courses in the area and as patches along the Limpopo and Shashe Rivers where there is still some floodplain vegetation. The distribution of vigorous vegetation in the EPA also tracks water courses and is particularly prominent in the Limpopo and Levuvhu floodplains and the Mwenezi River. The reddish shades on the slopes of the flat, basalt topped hills (e.g. south-east of the Limpopo-Levuvhu confluence) suggest that there may be GDEs in these situations as well. The unusual distribution patterns of reddish areas in the northeast part of the pilot area (in Mozambique) needs to be examined further.

Figure 13.17: A false colour satellite image of the WPA showing vigorous vegetation as orange to red shades with bare areas in white and low vegetation cover or dead vegetation in blue shades.

An alternative to this is the normalized difference vegetation index (NDVI) which uses the red and near-infrared bands to derive an index which also gives high values for vigorous vegetation (Figure 13.19). In this figure the vigorous vegetation is represented by blue shades (e.g. the centre-pivot circles) with low cover being indicated by orange to yellow shades. The NDVI index reduces the effects of the poor reflectance of the dark basalt-derived soils seen in Figure 13.17. The results of an NDVI analysis of each dry season and wet season pair were compared by subtracting the dry season values from the wet season values. Although simple to do, the results produced by this process were disappointing because they did not pick out the areas that were predicted. The main reasons for this were that: • The images needed to be accurately calibrated to ensure that the effects of the

differences, such as the angle of the suns and clarity of the atmosphere, did not bias the results.

• The NDVI is a relative index and not based on an absolute value so a lack of a shift does not mean there has been no change in that pixel.



Figure 13.18: A false colour satellite image of the EPA showing vigorous vegetation as orange to red shades with bare areas in white and low vegetation cover or dead vegetation in blue shades.

Figure 13.19: A processed satellite image of the WPA showing the normalized difference vegetation index (NDVI) which shows vigorous vegetation as red shades with bare areas and low vegetation

cover or dead vegetation in paler shades. Note how this reduces the effects of the dark basalts north of the Limpopo in Figure 13.17..



A brief test of a more complex index, the tasselled cap, was carried out. This index uses all the frequency bands in an image to compute, among others, a brightness, wetness and

greenness value for each pixel (minimum section of land that can be resolved). These three combined with the NDVI give a much more rigorous and explicit identification of features

which can be interpreted as GDEs. The initial test was done using uncalibrated images but, even so, its looks to be a substantial improvement on the NDVI alone as it can clearly

distinguish water, bare soil and dead plant material. This approach will be taken further. 13.4.4 Conclusions A few studies have been done of the various ecological linkages between floodplain ecosystems and those in the adjacent dryland areas but we have not been able to find one which specifically examined the role of groundwater in sustaining these ecosystems. The problem is not that groundwater has been overlooked, it is often mentioned, but rather that there have not been any quantitative studies of these relationships or even much conceptual thinking about them. The same applies to the indirect and direct socio-economic benefits to humans from these systems. The kinds of benefits can easily be identified, the problem is that quantitative studies that illustrate these benefits are lacking. The ecological requirements of GDEs for groundwater (e.g. flow requirements, discharge rates, water levels) are poorly understood. Present knowledge is inadequate for doing more than guesswork. This means that the managers will have to adopt an adaptive approach to dealing with meeting the GDEs water requirements. The development guidelines for management will have to be done through experimentation, observation and adjustment – learning by doing. This in turn, will mean that monitoring systems will have to be designed to provide clear warning signals by monitoring the right things at the right times. Those warning signals will have to be communicated rapidly and effectively to enable abstractions to be adjusted to prevent or minimize any adverse impacts on the affected ecosystems.



14. GROUNDWATER VALUATION IN THE LIMPOPO BASIN: A PRELIMINARY SCOPING OF ISSUES

Groundwater provides many types of services to humans and to the environment. In most cases it is used directly for agricultural, domestic, industrial or recreational activities. Some evidence provides an indication that in this case study, at least on the Zimbabwean side, groundwater is not used to its full socio-economic potential (Waughray, Lovell & Mazhangara 1998). However, the economic value of groundwater is not only influenced by direct use, but also by expectations on future supply as well as by the potential environmental damages caused by the over-extraction of groundwater resources. When market prices for groundwater exists direct or private costs are usually reflected well. This is usually not the case for the cost of replacing the resource in future, referred to as the user cost, nor for the external environmental costs. Using market prices for valuing groundwater can only be used with confidence if groundwater, or water, is traded and the market is reasonably competitive. When groundwater is used as a factor of production, such as in the case of agriculture via irrigation, the changes in net income from production due to changes in the groundwater supply provides a partial bur reliable indication of its value. Like in the case of using market prices, user costs and external costs are not accounted for. The advantage is that this method can be used to value groundwater that is not traded in the market. Expressed preference techniques, such as the travel cost method can be applied if people expend personal resources to get to and extract groundwater. However, this only gives a very partial account of the total economic value of groundwater and is usually used in the context of recreational activities. Stated preference techniques, such as the contingent valuation method, measures the willingness to pay of individuals or households to maintain or improve the environmental quality of groundwater resources. It is the only way to measure non-use values, such as preserving groundwater for future generations, or to measure the value of the resource’s existence. Through this technique the level of demand for certain groundwater services is hypothetically constructed. Therefore, using the private cost of operating boreholes does not reflect the economic value of the water. Existing charges for water supplied from government water works do not reflect its economic value either as such rates are mainly based on the engineering costs of supply and maintenance. To use such operating costs, charges or tariffs as a proxy for groundwater would give an indication on the value of water, but will only accidentally reflect the economic value of water. The western pilot site includes parts of the magisterial district of Musina (NP341) in South Africa, parts of the Beit Bridge administrative district in Zimbabwe and in Botswana parts of the Bobonong district. The eastern pilot site include parts of the Mutala magisterial district (NP342) and the far northern area of the Kruger National Park (CBDMA4) in South Africa, parts of the Mapai, Pafuri and Eduardo Mondlane districts in Mozambique and parts of the Beit Bridge, Mwenezi and Chiredsi administrative districts in Zimbabwe. The demands on groundwater within these areas and the tariffs for groundwater in the area and the populations statistics for the two pilot study areas are illustrated in Tables 14.1 and 14.2.



Table 14.1: Water use and costs

The estimated number of users in the area are:

Table 14.2: Population statistics in the pilot staudy areas

These numbers can give an indication on the size of the local market for irrigated crops. Open markets for groundwater do not exist. Therefore, to obtain the value of groundwater the production function of agricultural crops using water as an input will have to be determined first. In such a way the benefits of groundwater in the production process can be established and weighted against the costs of doing so. Following Acharya and Barbier (2000:250) the aggregate production function for crop i, can be expressed as:

)(,.....( 1 RWxxyy iijiii = for all i and the associated costs of producing yi are:

WRcXCC wjxi )(+= for all i where Ci is the minimum costs associated with producing yi during a single growing season, cw is the cost of pumping water and Cx is a vector of cxi….cxj strictly positive, input prices associated with the variable inputs xi1…xij. The amount of water available to the farmer for abstraction is dependent on groundwater level, R. The costs of operating groundwater abstraction will increase as the lift (difference between water table and pumping elevation) increases (see Ebarvia 1997). As discussed earlier, the economic value of water is not only a function of the cost of abstracting it, therefore cw will be on the lower end of the scale. When a full economic value assessment has been carried out this term need to be expanded in the cost of production function. To obtain the value of production the number of hectares that are irrigated broken down per type of output, the tons that were produced and the demand for the product, as expressed in (local) market prices, will be needed. Only in this case can changes in economic value be determined through changes in water supply (groundwater level) as modelled through the above production and cost of production functions. In the South African side of the case study, irrigation is used for vegetables (mainly tomatoes en potatoes), lucerne and oranges to a total of 5 600 hectares. In Zimbabwe, mainly oranges are irrigated (approx. 330 hectares as state schemes, approx. 570 hectares private), while in

Population statistics

Total populationApprox. Population density/km2 Total population

Approx. Population density /km2

Botswana 30 000 5Mozambique 33 000 5South Africa 5 000 1 140 000 33Zimbabwe 20 000 4 31 500 6

Western pilot study area Eastern Pilot study area

Water use (m3/year) and costs (R/m3)Country Mining Domestic Cost (R/m3) Consumption (m3/month)

m3/year Hectares m3/year m3/haBotswana 0 Approx 500 5 000 000 10 000 1 040 000 R 2.15 0-5

R 5.30 5-20R 11.00 21-40R 13.50 >40

South Africa 9 000 000 5 600 55 000 000 10 000 1 500 000 R 1.50 flat rateMozambique 0 R 15.00 flat rateZimbabwe 900 9 000 000

Agriculture



Botswana it is mainly mealies that are produced for subsistence use (approx. 500 hectares). At least 10 000 m3/hectare is required for current production in South Africa and in Botswana. At the time of writing no numbers were available on the yields acquired per unit of additional irrigated water1. In summary, one cannot simply use existing groundwater costs as an indication of the economic value of the resource. These costs bear no direct relation to the private costs of abstraction, and much less so on the value of secured future supply and the value of clean water to the ecosystem. None of these three components of economic value can be established at the moment. As there is no competitive market for groundwater in these case studies, the production function approach can be applied to calculate the private cost. More information is required on:

- Refined numbers on irrigated crops and hectares - yields per crop per hectare with and without irrigation - costs of all inputs in production - operating costs for the abstraction of groundwater. - (local) market prices for different crops

To establish the cost of future use foregone, or the user cost, one way would be to calculate the cost of replacing the groundwater asset at some future date. However, this assumes that substitutes are available. To calculate the external costs of groundwater abstraction would require, preferably, site-specific information on increased pumping costs when the water table declines in access of the recharge rate. This situation is called a reciprocal externality2. Unidirectional externalities are the contamination of groundwater by leachate from dump sites, leakage from underground storage tanks of gasoline stations for example, interface of acquifers with polluted surface water, or damages from subsidence of overlaying lands. More specific data will have to be collected on irrigated crop production, and a resource economist will have to develop a better site-specific understanding on the costs of operating boreholes in the region and the third party costs of overabstraction and groundwater pollution, before an economic valuation model is even attempted.

1 These numbers are based on preliminary information and should be regarded as preliminary

estimates at this stage. 2 Each agent imposes costs on others, and each experiences costs imposed by others (Dasgupta 1982).



15. FIELD VISITS TO AND DISCUSSIONS RELATED TO THE TWO PILOT STUDY AREAS 15.1 Introduction Following the meeting in Gaberone and the selection of the two pilot study areas, short visits were made to the two areas by members of the project team. These visits were aimed at collecting more specific information on the two areas specifically around the socio-economic conditions in the two areas, ground water use including mining and agriculture, Transfrontier Conservation Areas, and the identification of stakeholders to attend the planned stakeholder workshop. Two of the field visits concentrated on the socio-economic, geohydrological and water supply and use aspects in the Pilot Study areas, whereas a third visits addressed issues around the Transfrontier Conservation Areas, ecology and GDEs, and the water use from the Limpopo River alluvial aquifer between Zimbabwe and South Africa by mining and agriculture. One of the reasons for the field visits was to engage in a dialogue with local inhabitants about their Part of the reason for the field visits were to engage in a dialogue with locals about their perceptions around the use, availability and quality of as well as dependency on groundwater resources and also to observe the situation on the ground. 15.2 Socio–econimic aspects During the visits semi formal interviews were held with a range of people including government officials from different ministries such as water, agriculture, land boards, and the mining industry and community leaders. The objectives were to capture a wide variety of water related issues, such as those affecting the management, use, availability, accessibility and quality of groundwater resources from a social and technical point of view. For the socio-economic aspects, the approach was to design a semi-structured interview schedule that could be comfortably administered to a wide range of respondents: local/rural residents, water committee structures, water managers, etc. This interview schedule was, however, not specifically designed for interviews with water authorities and other officials. However, when the opportunity arose, issues such as resource constraints (technical expertise, expertise in participatory planning and financial resources) experienced by government in the planning and implementation of water, sanitation or agricultural services, were explored. Where water officials were interviewed, discussions often addressed these issues in more detail. Apart from the use of a semi-structured interview schedule, a degree of observation was used to either corroborate or refute some of the points made by the respondents. It is understood and appreciated that water management strategies often would have to be implemented at a community level and therefore the design of these interventions would necessitate an understanding of the community level attitudes towards the resource. Due to time constraints, interviews for the social assessment were only held in some of the settlements and most, observations were made on short visit conducted .



From the observations made during these visits it appears that the within the pilot study areas in Botswana and South Africa that there is a strong economy, a well-developed infrastructure is in place and there are more signs of development than observed in Mozambique and Zimbabwe. The infrastructure is also well defined and developed with further developments of water infrastructure going on. Rural settlements in South Africa and Zimbabwe very few signs of economic activity except for the mining and agriculture taking place especially in South Africa and to a smaller degree in Zimbabwe. Mozambique appears to be the most impoverished part with almost no economic activity. The villages are very scattered throughout the area except for the few gravel roads, there is virtually no infrastructure in place. Some of the challenges that the project team was faced with were the lack of scheduled appointments, interviews with officials, lack of data and language.

Appointments could not be set beforehand because of a lack of time, difficulty in identifying appropriate individuals in the selected remote parts of the four countries and the non-existence of communication infrastructure in places.

A number of interviews were conducted with officials exploring issues such as water availability, costing, resource management, accessibility and institutional arrangements. , On few occasions, it was possible to interview both officials and community members, sometimes resulting in conflicting views expressed. These then had to be tested through field observations. Although information on for example water supply schemes, irrigation, cost and population density and water quality was presented to us, the level of accuracy varied. Where data and reports were not readily available, arrangements were made with the relevant authorities to forward this. The project team members managed to engage with the respondents in most of the local languages except in the more rural parts of Mozambique where Portuguese was the predominant language. In such instances use was made of local interpreters..

15.3 Country Reports 15.3.1 Botswana Interviews were conducted in Bobonong, a village situated in the Bobirwa Sub-District, northeastern Botswana with representatives of government departments. Bobonong is the main settlement in the Botswana part of the Western Pilot Study area. . The interviews were with : • The water engineer and Head of the Bobirwa Sub-District Water and Waste Water

Management who is responsible for all technical aspects of water supply and sanitation in the Sub-District.

• The Chairperson of the Village Development Committee, and • The District Agricultural Officer for Bobonong and Selebi Pikwe, Department of

Agriculture. Settlements visited and their water supply

Settlements visited:

Bobonong, Gobojang, Mabolwe, Semolale, Molalatau, Matahatahane, Tsetsejwe.



All villages within the Bobirwa Sub-District are supplied from and dependent on groundwater resources. Table 15.1 provides information of the level of groundwater supply to the villages within the Bobwira Sub district and within the boundaries of the pilot study area as at January 2003.

Table 15.1: Water supply to villages within the Western Pilot Study area. Village Population Demand

(m3/day) Supply capacity

(m3/day) Comments

Bobonong 14 622 1 750 1 092 Deficit – 8 new boreholes planned

Gobojango 1 631 93 156 Demand met Semolale 1 145 70 44 Deficit Mabolwe 735 50 155 Demand met Lepokole 505 30 47 Demand met Mathathane 1 845 100 202 Demand met Mothlabaneng 1 276 50 68 Demand met Molalatau 1 788 167 178 Demand met Tsetsebjwe 3 457 140 136 Slight deficit Sefhope 3 821 148 131 Slight deficit Len le Morit 262 39 20 Deficit Total 42 314 2 598 2 209

As shown in the table above the water demand in most of the settlements in the pilot study area supplied by the Bobirwa Sub-district Water and Waste Water Department, is met by the existing infrastructure, with the exception of Semolale, Tsetsejwe, Bobonong and Len le Morit which are experiencing water shortages. To address this shortage new boreholes have been drilled and are currently being equipped. The water quality is also of a high standard except in Mathathane where there is some pollution of ground water reported, apparently originating from poor sanitation systems.

Level of water, sanitation and waste management services in Bobonong: Bobonong residents have access to public standpipes as well as yard connections. The original design was to service 100 households per standpipe. As a result of yard connections installed during the last few years, this figure has dropped to an average of about 50 households per standpipe, and in places as low as 12 households per standpipe. The ultimate aim is to install yard connections at each household, and currently a large number of these connections have already been made, although there is still a backlog as far as the connections are concerned, this is addressed by the Council. . At Bobonong a combination of pit-latrines and a septic tank systems are in use, with a waterborne sanitation system currently being installed. The introduction of the water-borne system comes at a price for residents since each household will be required to pay a once-off payment of P1000 for installation. The waterborne sanitation system is not operational yet, as the sewage treatment plant is still under construction. The aim is to provide this service to all households, but financial constraints may slow down this process. A major reason for deciding to implement a waterborne sewage system, was to prevent further ground water pollution as the village expands. As a result of the pit latrine sanitation systems, pollution of shallow groundwater resources close to the village has been detected and has rendered some of the existing domestic water supply boreholes unusable. The implementation of this system will result in an increased demand for water, but groundwater assessment studies have indicated sufficient reserves.



Water, Sanitation and waste management services in other villages Water in all other villages within the Sub-district is supplied through public standpipes, and to a small degree in the larger villages, yard connections are available. In these villages only pit latrine systems are in use. The aim is however to upgrade both the water supply and sewage systems to yard connections and waterborne sewage systems. The time frames for implementation of these plans are dictated by the availability of financial resources, both from the authorities, as well as private individuals. From geohydrological studies, water availability is not regarded as a limiting factor. Value of Groundwater As ground water is the only source of water for the region, its strategic value to the region is clear and therefore must be managed judiciously. This aspect is well understood by the water managers, but not tested with the community at large during our visit. The abstraction and distribution systems in some of the villages (for example Bobonong where population has doubled in the last ten years) are currently under strain, but are being addressed through the drilling of additional boreholes and the upgrading of the distribution network. According to the geohydrological studies, recharge is in excess of the forecasted use. Service levels and Water Use Water Access There is general access to public standpipes and this water is supplied free of charge. Initially, residents were required to pay P200, purchase their own connection material and were responsible for excavation to have yard connections. In Bobonong the Council is currently upgrading water access through a water scheme that is aimed at the residents acquiring yard connections at a subsidised fee of P200. . In this scheme, the council provides the connection material and is responsible for the excavation. After October 2003 the fee for yard connections will increase to P750. The community apparently is of the opinion that a P750 connection fee is expensive. Since the start of the subsidised connection scheme, applications for yard connections have increased resulting in back-logs. Where standpipes have been damaged, or do not yield any water, the council provides water through tankers to the community. All residents (even those with yard connections) have equal access to a limited volume of free water from standpipes. Of great concern to the Council is water wastage at standpipes. Current regulations do not allow the provision of water from the standpipes for cattle drinking or gardening. However, this is practised on a wide scale. To address the water wastage from the public standpipes, the Bobonong Council is in the process of introducing a token system which will; allow access to a limited amount of free water. If this quota is exhausted, additional tokens have to be purchased from the district office. Water Quality

The community has access to safe water as confirmed by the analytical results of water tests by the Department of Water Affairs. The water is classified as “Class 2” as defined by the Botswana Bureau of Standards (technically expressed as STD-BOS 32:2000 Class 2), which means water quality is of an acceptable standard level for human consumption.

In Bobonong, some boreholes have had to be abandoned for domestic use because of



groundwater pollution due to the pit-latrine and septic tank sanitation systems. The boreholes are still in use, but the water is used for construction and other purposes except for household consumption. Water Use Water provided by the Council in Bobonong and the surrounding villages is mainly for domestic use. Where water is to be used for small-scale economic activities (for example brickmaking) this has to be purchased from the council. Other uses of groundwater such as livestock watering, is not allowed. Watering of livestock by leaving public standpipes to run overnight does occur and has been identified as an undesirable practice identified by both the Village Development Committee as well as the District Administration. Water for livestock and ploughed field irrigation is to be supplied from privately owned boreholes at the cattle post outside the villages. This regulation is flouted by some villagers and is worsened by the fact that is it not being enforced by the council. Groundwater is also for the irrigation of crops cultivated by small-scale farmers. Small-scale farmers lease land from their tribal authorities and are responsible for drilling, equipping and maintaining boreholes at their own cost. There is no levy on this water. Permission to drill boreholes has to be sought beforehand from the Land Board and boreholes have to be registered with the Department of Water Affairs. The authorities impose restrictions on the density of boreholes. As a guideline to the density of boreholes allowed, a figure of one borehole within an 8-10 km radius were mentioned. There is currently no system in place to monitor the abstraction rates nor is the water quality tested. Water Management The responsibility of identifying, assessing and testing of the groundwater resource is with the National Department of Water Affairs. Once a sustainable resource has been identified, finances are provided by the National fiscus to the local authority for developing the resource. The local authority is responsible for water supply, operation, maintenance and cost recovery in the sub-district. There is a Village Development Committee in each village, which is responsible for monitoring the appropriate usage of water, overseeing the running of public standpipes, and reporting any grievances and damages to the council. A concern raised by the chair of the Bobonong Village Development Committee (VDC) was about the lack of consultation by the Council with VDC on decision-making. This includes among others, the establishment of the water tariffs and the yard connections. Since this committee represents the community, consultation with it is important to secure support from the community on Council/Government-driven initiatives. Monitoring (even occasional) of the groundwater system (water levels, yield or quality) is not regularly performed by the local authorities or Government. General Issues

• Issues affecting the community identified by the VDC and observed during the visit • Lack of availability of water from public standpipes; • Cost of installing yard connections; • Affordability of water once yard connections have been installed; and



• Lack of support by some villagers of water management practises that would protect the resource and result in more water for those who relied upon the public standpipes Limited involvement of VDC in decision making at Council level.

• Issues affecting council

• The exorbitant costs associated with the maintenance of public standpipes; • The lack of enforcement of water management practices at a community level; • Backlog in repairs of standpipes; and • Backlog in installation of yard connections. 15.3.2 South Africa Introduction Both the pilot study areas cover portions of the northern part of South Africa bordering on the Limpopo River. However, in terms of land use the western and eastern areas are totally different. Whereas approximately 50% of the eastern study area is set aside for rural settlements, approximately 30% is covered by the Kruger National Park and other conservation areas, with the remainder being commercial farming area, the western study area is almost entirely used for commercial stock and game farming (approximately 80%) and conservation (approximately 15%), some irrigation farming and mining areas (approximately 5%). Therefore the field visits in terms of groundwater use, concentrated on the rural, irrigation farming and mining areas as these are the largest groundwater consumers. Attention was also given to the existing conservation areas and proposed Transfrontier Conservation Areas (TFCAs) to assess the possible impact on GDEs in the event of increased groundwater use during extended drought periods. Eastern Pilot Study area The Vhembe District office of the Department of Water Affairs and Forestry located in Thohoyandou, and some of the villages in the area were visited where discussions and information on the water supply situation to the rural areas in the district were discussed. The satellite areas Makuya, Massisi, Malamulele and Mutali are under the jurisdiction of the Department of Water Affairs and Forestry (DWAF) office in Thohayandou. These areas are served from groundwater as well as surface water sources. Most of the villages within the Eastern Pilot study area are, however, served from groundwater sources. Towards the southern boundary and the boundary with the KNP (Malamulele), some villages also rely either exclusively or partly on surface water because of their proximity to Levhubhu River. Some of the smaller villages do not yet have their own water supply system, and are supplied by tanker. The DWAF is currently the bulk water supplier for the area and is responsible for the design, construction, implementation and maintenance of these schemes. In about two years from now, all these schemes will be transferred to the local municipalities who will then manage these. Surface water schemes supplying the area source their water from the Vondo, Nzhelele, Chibase, Dangadzivha and Luphephe Dams, and weirs in the Levhuvu River. The design capacity of the Vondo scheme is 4.2 Ml/d, but is currently operating at only 3.2 Ml/d. The Funduzi dam is not used for water supply to the area, whereas the Mapuleka dam is only used for irrigation. The northern part of the Mutale area is currently served by groundwater based schemes, but the reticulation design is such that once sufficient capital is available for the completion of the water supply scheme from the Lhephephe Dam, the



existing groundwater supply scheme will be phased out and replaced by a surface water scheme. Although no confirmation for this could be obtained, reasons often provided for these decisions include: 1) Engineers who often design these schemes have more confidence in surface water sources in providing a sustainable supply than in groundwater, 2) residents often insist on surface water schemes because it is perceived that these provide a better water quality than groundwater (lower EC, lower fluoride, etc), and 3) surface water schemes often have a treatment plant associated with them (for example “Package Plants” in Thohoyandou area). According to DWAF officials the existing production boreholes will, however, be maintained as a backup supply to the area. All villages in the area have access to water either through handpumps (smaller villages), standpipes and yard connections (larger villages) or from water brought to the villages by tanker (mainly the smaller villages). Where villages are dependent on water from engine driven boreholes, residents pay some monthly fee to the Village Water Committee (VWC) for the purchase of diesel. Although DWAF issues bills to the Municipality for the amount of bulk water supplied, these are not paid by the municipalities, apparently due to the fact that the municipalities are financially not in a position to pay. All yard connections have water meters installed, but except for Thohoyandau, no billing system is yet in operation. In the Mutali and Masisi areas, meter audits are currently done (verifying accuracy of meter readings, reconciling meter numbers and stand numbers and owners, etc), but no billing system exists yet. Figure 15.1 was taken in the Masisi area and shows a water meter (with illegal take-off point!) with its registration number (174-392) clearly marked. According to DWAF officials, extensive public participation processes were conducted in the district to explain to the residents the reasons behind the introduction of a billing system. The residents appear to have accepted the concept and are willing to pay. As no official billing system is yet in place, this has not been tested in practice. Another reason cited for willingness to pay, is the vandalism associated with public standpipes, which leads to unavailability of water to residents. Apparently there has been agreement between Municipalities in the Vhembe District that the tariff for water will be R1.50/m3. Yard connections are currently installed at a cost of R285/consumer.



Figure 15.1: Water meter at yard connection in the Masisi area showing the special meter reference numbering system designed for the area.

Most villages have a Village Water Committee (VWC) that attends to all matters related to water supply. The VWC reports to their ward representative who again reports to the Satellite Office of DWAF. The Tshwalowe and Bale villages towards the northern part of the Eastern pilot study area were also visited. Semi-structured interviews did not take place at either of these sites because interviews with appropriate respondents could not be scheduled in time. In both these sites, unofficial discussions were held with village inhabitants from each settlement. Tshwalowe Village The village has a population of approximately 200 households. There is a reticulation system in place and the community can access water from standpipes. During our visit most of the standpipes appeared to be non-functional, most probably due to a diesel shortage suggesting that the community cannot afford to efficiently run the motorized water pumping scheme. Each household pays a flat rate water tariff of R5/month. The chief is responsible for collecting the water levies and purchasing of diesel, whereas operation and maintenance of the pumps is usually the responsibility of the VWC. The villagers rely on water pumped from the nearby Ngwanedi River for subsistence farming. Water is pumped into a storage tank and then released onto a cement constructed canal running on the western boundary of the village towards the fields where flood irrigation is practised. Water from the canal is also used for household requirements. . An issue of concern is the cattle that drink directly from the river and congregate on the banks of the river. This can be a serious source of pollution of the water that is also used for irrigation and domestic purposes. Bale Village • The village is comprised of roughly 180 households and the following observations

were made during the visit: • The village has a few public standpipes; • Some households have private boreholes (see note below); • They use a pit latrine sanitation system; and • The residents contribute an amount of R5 per month to the chief to purchase diesel

for the water pump. A practice that is observed frequently in the settlements in the Limpopo Province, and which was observed in many of the settlements visited, is that of cattle kraals distributed throughout a settlement. These occurrences, coupled with the presence of private boreholes drilled on individual stands, are of great concern as they represent potential point sources of groundwater pollution (especially nitrate). To test this statement, a water sample was taken from a private borehole located next to a cattle kraal in the Bale village and submitted for specific chemical analyses. The nitrate concentration (reported as N) in this water was an alarming 203 mg/l! WHO drinking water standard recommends <6 mg/l. Electrical conductivity was 233 mS/m and chloride concentration was 245 mg/l. Conservation areas During a visit to Crook’s Corner at the confluence of the lower Levuvhu and Limpopo Rivers in the Kruger National Park, the occurrence of GDEs and the geological settings in this northern part of the park was assessed, both on the floodplain and in the surrounding dryland



(upland) areas. GDEs in this environment are key habitats sustaining a variety of plant and animal species which do not occur in the adjacent dryland areas or use the riparian habitat as shelter and range out into the adjacent areas. The information derived from Tinley’s cross section of the Limpopo floodplain could be generalised to these areas as well. The area was severely affected by the recent (2000) floods which reached about 30m above the river bed at their peak. The KNP has a research strategy in place which recognises the importance of groundwater and acknowledges that research into the environmental role of groundwater has been neglected in the past. They certainly will support the follow-up GEF project should it go ahead to do research into the environmental roles of groundwater in the natural ecosystems of the Pafuri area. The development of the Greater Limpopo TFCA is progressing well but is less advanced than the one around the Shashe-Limpopo Confluence. A MoU was signed in 2002 between South Africa, Mozambique and Zimbabwe to develop a joint joint management plan and various task groups have been formed under a SA Department of Environment, Agriculture and Tourism (DEA&T) Ministerial Committee. An institutional framework has been established with a • Trilateral Ministerial Committee over a • Trilateral Technical Committee (5 representatives from each country) plus the project

coordinator; over • National Technical Committees (one for each country each with seven members); • Ad hoc specialist committees can be established and would report to the any of the

levels of committees above. There are also general water sharing agreements which have been established through Limpopo Basin Technical Committee. A 5-km wide “resource use zone” has been created along the Limpopo and Shingwedzi Rivers to meet the needs of the communities living in the TFCA. There is some concern about the state of the Levuvhu River which has been seasonal since 1991/2. Plans to build a direct road connection to Zimbabwe/Mozambique have been formulated and seven options are being considered at present. A serious problem for the TFCA are the mine fields which extend over some 60km along the Mozambique-Zimbabwe border from South Africa to Eduardo Mondlane and the ammunition stores points along the borders. According to the SANP some GDE related research work has been and still is conducted in the area. This includes the occurrences of springs and other GDE-related features in the Pafuri area, mapping of water pools and hot and cold springs in this area, and some ancient river bed studies. The Pafuri area is regarded as critical for the conservation of birdlife, particularly for the waterbirds which breed in the pans in the “panveld”, a unique phenomenon in the KNP. The riverine and floodplain forest are key habitats for many animal species. There are also a number of cultural sites in the area, probably second only to Mapungubwe in the Shashe area. The Western Study Area The visit to the western pilot study area was confined to the conservation area, the Venetia diamond mining activities and the irrigation farming along the banks of the Limpopo River.



The Shashe Transfrontier Conservation Area (TFCA) The idea of the Shashe TFCA has been in development for some time and negotiations are well advanced. At present the SANP are setting up infrastructure in the Vhembe-Dongola core area of the park (the old provincial nature reserve). The Maramani community in Zimbabwe are seen as key players in this TFCA because they control a key land area bordering on the river and on Botswana and negotiations still have some way to go. The community comprises some 5000 people who are largely dependent on water from the Shashe River and from groundwater associated with the alluvium in the Shashe River. An Italian funded NGO, CESVI, have established good working relationships with the community and would be important contacts for future stages of the project. Some CESVI representatives are stationed at Beit Bridge in Zimbabwe, and brief discussions were held with them during the visit. A concern in this area is the potential water needs of the Venetia mine in the future (see notes on Venetia below). A key area that will require restoration is the extensive floodplain of the episodically flowing Kolumpe River. This flood plain apparently gets filled by backed-up water when the Limpopo is in flood and is regarded as ecologically important. According to Mr Rassie Erasmus of Venetia Diamond Mine, the lower part of the floodplain is under irrigation farming which could make this aim difficult to achieve. No research projects on the natural resources of the area have been initiated yet. The Shashe TFCA does not have an institutional structure yet. The Venetia Diamond Mine The Venetia Diamond Mine in South Africa is some 30km directly south of the confluence of the Shashe and Limpopo Rivers and approximately 30 km northeast of the town Alldays. The water supply to the mine is currently from an off channel storage dam filled during times when the Limpopo is in flood, and supplemented by groundwater pumped from the alluvium in the river and along the southern banks of the river on the farms Greefswald and Schroda. These two farms are just downstream of the confluence of the Shashe River with the Limpopo River. New boreholes are currently drilled on the farm Schroda. The mine has a very sophisticated computer-based system for managing the water abstraction process from the alluvium and the off-channel supply dam. This system continuously monitors water-levels to ensure that they stay within pre-determined limits. All the wellfield information (e.g. pumping rates, water levels) is transferred to a central control point and relayed via a radio link to Messina. The TDS of the water supplied varies from 20 to 2000 mg/l. Since 1991 monitoring of the moisture stress levels in the leaves of Croton megalobotrys, an understorey shrub/small tree in the levee forest community, and mortality along fixed transects is done by staff from the Limpopo Province Environment Affairs Office in Polokwane. This monitoring is required by the permit conditions and starts after the Limpopo ceases flowing. Water levels and moisture stress levels are used to set pumping rates and to determine which wells are to be pumped. Monitoring reports are submitted to DWAF quarterly and annually. Venetia Mine is undertaking two developments at present. One is to move all their extraction boreholes to the Shroda wellfield so that no pumping will be from the alluvium on the farm Greefswald.. The second is to reduce water use and redesign the system to increase storage so that the mine will only abstract water when there is surface flow. Five new abstraction boreholes are being drilled in the river bank at Schroda. Subsurface well heads and minimal piping are used to avoid vandalism. The new linear well field is more spread out than before; abstraction from the old field introduced interference effects between wells. Venetia intend to pump an extra 5 x 106 m3 during the river’s surface flow (flood) period and store this in an



offline dam; this water would be classified as surface rather that groundwater. This would reduce or even avert direct groundwater abstraction. Their total permit is for only 4 x 106 m3 and they are currently abstracting around 4 x 106 m3 per year. They estimate that nearly all the water they are abstracting is coming from the Shashe system as the Limpopo barely flows at all. A water-user association for the South African farmers has been established and would participate in any initiatives aimed at establishing cross-border relationships for water resource management. Greefswald has a well developed riparian gallery forest in much better condition than the previously cleared Schroda farm. Tree species include: Ficus sycamorus, Combretum imberbe, Terminalia prunoides, Croton megalobotris, Acacia xanthophloea (fever tree), Faidherbia albida (anaboom), Xanthocercis Zambeziaca (nyala tree, meeting tree), and Sclerocarya birrea. The forest also has many creeper and liana species. The fauna observed during the visit included: bush buck, duiker, klip springer, giraffe, bush pig/ wart hog, baboons, vervet monkeys, dassies, hornbills, sun birds, impala, Martial eagle. There also are elephants, leopards, kudu and lions. Baobabs, mopane and palms are characteristic of the floodplain and hills away from the gallery forest. Irrigation schemes on the Limpopo River Extensive privately owned and developed irrigation farms have been developed along the southern (South African) and northern (Zimbabwe) banks of the Limpopo downstream and also just upstream of the confluence with the Shashe River. These irrigation farmers are well aware of the critical issues around water associated with the Limpopo floodplane and their dependence and interdependence on the limited resources of the Limpopo alluvial aquifer. As a result they have, together with the authorities, been instrumental in the setting the permit conditions for abstractions imposed on the Venetia diamond mine. The South African farming community is, however, concerned about the ever decreasing contribution to the water resources (surface and groundwater) in the Limpopo River as a result of increase in water consumption in the upper Limpopo River and the main tributaries, the Shashe and the Moutloutse Rivers. Irrigation on the Zimbabwean side of the Limpopo, is of particular concern, as apparent no control on abstraction is enforced by the authorities. Most of the South African farmers are well aware of the consequences o overabstraction and irresponsible water management. As part of their management plans they limit water level drawdown to 2m, blend the irrigation water from different sources to minimize quality fluctuations, monitor water quality on a daily basis, and abstract most of their water during periods of surface flow and store this water in specially constructed storage dams, Upstream of the confluence with the Shashe River, the Limpopo River obtains most of its water from the Motloutse River which originates in Botswana. Most farmers in the region are in favour of establishing a Water User’s Association and would support initiatives of transboundary water resource management. South African farmers are also concerned about the lack of clarity around the recently introduced water user registration process, and the water use permit application process. Some farmers have registered the potential abstraction based on total maximum borehole yields while some registered actual abstraction. Water billing is, however, based on the registered figure which may be much more than the actual use.



15.3.3 Moçambique The three main centres on the Mozambique side of this pilot study are Pafuri (on the SA Mozambique border), Mapai (along the Limpopo River) and Chicualacuala (on the Zimbabwe Mozambique border). The road network within the Pilot study area is poor and there is no bridge across the Limpopo within the study area. Only one informal crossing point exists at Mapai where a ford provides for crossing the Limpopo during periods of low flow. Two formal interviews were held in Chicualacuala, one with a District Administrator and another one with technical officer of the same office. A number of informal discussions were held with local residents met during the travels through the Mozambique section of the pilot study area. The information supplied by the District Administrator applies to the Chicualcuala District of which Chicualacuala village can be regarded as the main centre. On some maps Chicualacuala is also referred to as Eduardo Mondlane. The village is located on the border with Zimbabwe and its links to the outside world consists of a road and railway line providing access to Zimbabwe and the coastal areas of Mozambique. The Limpopo and Nuanetzi Rivers present a major logistical problem to access the pilot study area. There are no bridges across these rivers within the study area, and crossing the rivers during the rainy season is very difficult if not totally impossible, unless one is prepared to travel an additional approximately 150 km south along the Limpopo River. The Chicualacuala District is split into three Administrative posts: Mapai, Pafuri and Eduardo Mondlane. The village of Chicualacuala falls within the Eduardo Mondlane administration post. The 1997 census figure provide the following population statistics: Pafuri 15 171 Mapai 4 416 Eduardo Mondlane 13 455 Approximate total population for the pilot study area: 33 042 Background information on the settlements The dominant ethnic group in this part of Mozambique is Shangane with Portuguese and Shangane the two dominant languages spoken. The larger villages, i.e. Chicualacuala, Mapai and Pafuri are dependent on boreholes for their water supply. There are no water reticulation systems in these villages, and residents collect their water from a central reservoir or from isolated standpipes within the village. Sanitation is restricted to pit latrine and septic tank systems. Awareness and value of groundwater

This district, and especially the areas and villages away from the major rivers (Limpopo and Mwenezi), is heavily dependent on groundwater for domestic supply throughout the year. Groundwater is an extremely important resource in this district, given the surface water scarcity in the region and the large population dependent on groundwater. Those that are close to the river, also depend on groundwater during the dry seasons, sourced either from the saturated alluvium or boreholes and wells on the banks of the river. Water levels, except those associated with the alluvium, are generally deep (>80 m in Chicualauala) and water quality is often poor (because of the geological reasons). Service Levels

The main water supply in Chicualacuala and Mapai is from boreholes equipped with motorized pumps and belonging the Railway Company, CFM. These boreholes are pumping



into a one large reservoir near the railway station. In Chicualacualat these boreholes are pumped three times a week to allow sufficient recovery, and each household can collect water only once a week from the reservoir. Smaller communities close to Chicualalcuala access groundwater from handpumps (deep aquifers) and hand dug wells tapping perched, non-sustainable aquifers. Water supplied by the Council is accessed by a large majority of the community at one central distribution point, next to the railway station. General members of the community pay a tariff of 15 000 MT per week for approximately 400 l/week. Because the boreholes belong to the Railway Company (CFM) CFM employees and Civil Servants receive free water. This is a paradox in a country where unemployment is rife and where civil servants are considered to be the wealthier citizens of this largely impoverished country. The motorized boreholes are pumped on Mondays, Wednesday and on Saturdays. The boreholes are allowed to recover in between the non-pumping days. Different sectors of the populations collect their water on different days. Railway workers have access to running water in yard taps and don’t have to collect their water from the distribution point at the station. They have water available in their taps for one hour on a Saturday during which they have to collect water into containers for a week’s supply. The other groups generally use carts to carry water containers (~400l) to their homes. Residents of Chicualacuala who cannot afford to pay the water tariff get free water from the handpumps. Villages along the main rivers are mainly dependent on hand dug wells in the alluvium. Due to the deep groundwater levels and often poor technical state of the handpumps, acquiring water at the handpumps is a taxing task requiring more than one person. The responsibility of collecting water and bringing it to the households lie mainly with women and children Statistics were supplied by an administrative officer for the Chicualacuala District describing the number of boreholes per village in each of the three administration posts. This is reflected in Table15.2. However, only the data from the Mapai Administration post is useful because it stipulates the population of each village and the number of people that are being serviced by the operational boreholes. This allows one to calculate the percentage of people able to access water with relative ease. The data from the other two administrations only provides the number of people able to access a borehole and without calculating this as a percentage of the total population, one is unable to assess whether there is a reasonable access or not. What is apparent from this data, however, is that there are a high number of inoperative boreholes – for example five of the thirteen boreholes in the Eduardo Mondlane Administration Post were inoperative at the time of the borehole census. Another general concern with the data is that it is based on October 2001 Census . Nonetheless, a look at the Mapai Administration Post’s data reveals some interesting trends:

Table 15. 2: Mapai Administration Post Data

Name of Village

Popu-lation

No. of bore-holes

Damaged/ non-

operational boreholes

Oper-ational

boreholes

Population served

% of population

served

Mepuze 2 222 2 0 2 617 28% 16 de Junho 7 713 17 8 9 6 330 82% Mapai Rio 2 722 5 0 5 1 781 65% Chidulu 1 055 2 2 0 0 0 Total 13 712 26 10 16 8 728 64%



From this table, bearing in mind the limitations of the data, the following key facts can be gleaned: • 38% of the existing boreholes are not operational; • About 70% of the population, on average, have reasonable access to water from

boreholes; • There are large discrepancies in the access to water depending on which village one

lives in.

Water Use Groundwater is mainly used for domestic requirements. The district administrator claimed that people in his area are satisfied with the quality of groundwater (Measured EC in Chicualacuala was 128 mS/m), although it has a slightly salty taste. Livestock watering is mainly supplied by surface water sources (rainwater collected in low lying areas for example). Subsistence farming is practiced actively on the banks of the rivers where water is readily available and where fertile soils occur. However, these fields are vulnerable during periods of flood. In remote areas, villagers often also rely on rainwater collected in low lying areas. Due to a lack of water availability at schools, scholars bring their own water to school.

Sanitation In terms of sanitation, the locals use the pit-latrine sanitation system and there are reportedly no plans to upgrade this system due to a lack of resources. A water-borne sanitation system with septic tanks was in operation during the colonial days in parts of Chicualacuala, but this has totally deteriorated. Water Management There is a Village Water Committee which is responsible for collecting water tariffs. The Village Water Committee interacts directly with the District Administration office which in turn liaises with Provincial Government; in the case of Chicualacuala the Gaza Provincial Government. The District Administrator is responsible for water supply, repairs and maintenance of hand-pumps in the district. When new hand-pumps are installed, a local person is identified and trained to do minor repairs on damaged hand-pumps. The District Administration receives an annual budget allocation for water supply from the Gaza Provincial Government. The respondent from the District Administration office cited that these funds were insufficient. Of concern is the accuracy of information provided by the District Administrator on water services in Chicualacuala. He stated that the abstraction and distribution system from the Mwenezi River, 35 km southwest of Chicualacuala, was still functioning. During the site visit to the pumping station on the banks of the Mwenezi River, it was found to be totally deteriorated to a state of disrepair (probably as a result of a lack of maintenance during the civil war). It was clear that it has not been in operation for many years. 15.3.4 Zimbabwe Interviews were held with a number of people in Zimbabwe. These included • the Chairperson of the Makakaure Village Water Committee, • the CEO of the Rural District Council (RDC) with offices in Beit Bridge;, • Beit Bridge District Coordinator of the District Development Fund (DDF),



• Staff at the Agricultural Extension Services, Dept of Agriculture, Beit Bridge Area Co-ordinator, CESVI (Cooperzzione e Sviluppo – Italian NGO), Co-operation and Development, Beit Bridge

• Works technician< RDC office, Beit Bridge • Staff at the District Administratords Office, Beit Bridge.

A striking difference compared to those in the other three countries observed during the visit to villages in Zimbabwe relates to the nature the villages are designed and laid out. Villages in Botswana, South Africa and Mozambique appear to be more formally laid out and structured, i.e. regular street layout with fixed plot sizes, and clear boundaries to the stands and the villages. In Zimbabwe, at least in the areas visited, however, the houses appear to be widely and almost randomly placed over a much larger area than in the other countries. This results in ill-defined village and stand boundaries and no clear indication of streets between houses. Village communities are thus spread over a larger area. This makes the development and supply of infrastructure (for example water supply) more problematic and costly. 1. The total population in the western and eastern pilot study areas in Zimbabwe

are approximately 18 500 and 31 500 respectively. The main villages in the western region are Masera, Maramani, Zezani, Mashaba and Hwali, whereas in the eastern region Nuli, Matibi, Diti, Mabalauta, Malipati and Chikwarakwara are the larger villages. These areas are populated by Shona and Ndebele ethnic groups with Ndebele and Shonaalso also being the dominant languages spoken in the area.

Service levels and water use

Water supply for these villages is mostly based on groundwater sources and provided from boreholes equipped either with motorised pumps, wind pumps or handpumps. In total there are currently 460 boreholes in the district and approximately 600 hand dug wells. Of these boreholes, 300 are still operational, with <10% equipped with motorized pumps. About 66% of the hand dug wells are still functioning. Furthermore, whilst one borehole is supposed to serve a community that resides within a radius of 3 km, in practice this is seldom the case as boreholes are often either inoperative or run dry. This forces the community, and mainly the women and children, to walk long distances in search of water. According to one source, approximately 70% of the rural population in the district has access to water. Water from the boreholes is used mainly for household requirements and livestock watering, except where the villages are close to some of the larger rivers like the Shashe, Mzingwane, and Mwenezi.. The residents are in general not paying for their water consumed, but often do contribute to the operation and (basic) maintenance of the boreholes. The pump operators and members of the Village Water Committees usually provide their services on a voluntary basis. There is a general need for additional boreholes in the villages because the water supply is usually severely under stress during periods of drought and due to non-functioning boreholes and the normal population increases in the area. Promises of additional boreholes are often made by the authorities, but delays in providing these are common. Some limited subsistence farming is taking place along the mainly ephemeral rivers. Government funded irrigation schemes have been developed along the banks of the larger rivers. In some villages two-roomed homes are provided by the Government for pensioners. Some of these are provided with an outside water tank for rainwater harvesting. Sanitation facilities used in these villages are mainly pit latrine systems.



Water management The District Administration (DA) office is responsible for water supply in the district and through the District Development Fund (DDF) is responsible for drilling and maintenance of boreholes. On completion these are handed over to the community. The Zimbabwe National Water Authority (ZINWA) controls water resources in Zimbabwe and is responsible for monitoring of for groundwater levels and quality. However, in the current economic climate in the country, there appears to be very little, if any, monitoring done in the districts bordering on the Limpopo River. Some monitoring is done in cooperation with the Ministry of Health, who are responsible for water quality related aspects of water supply. The DDF resorts under the same Ministry as ZINWA and receives their budget from ZINWA. The DDF has initiated a Community Based Maintenance Programme (CBM) and have trained Water Committee members to perform basic maintenance on boreholes and hand pumps. The idea is to promote a sense of ownership in the community. Due to diesel shortages, many motorised pumps in the distinct are currently not functional. While the District Administration was previously responsible for buying diesel, the local communities have since assumed that responsibility. Water management in villages is the responsibility of Water Committees. The responsibilities of the Water Committees further include the collection of contributions from community members and the maintenance of hand-pumps. As part of the hand-pump maintenance programme, a local person is trained by the District Administration office to handle minor repairs. Though this was perceived to be a cost-sharing exercise between the community and the District Council, the intention was also to instil a sense of community ownership. The cost factor resulted in water shortages largely due to a lack of funds to purchase fuel. Through the CBM, village pump-minders are identified and trained on specialized hand-pump management by the DDF to deal with minor maintenance work. According to the District co-coordinator of the DDF the pump-minders are also issued with tools and receive salaries from the DDF. Contradictory information to this was however, provided by the Chairman of the VWC. When villagers experience water related problems, they approach the Village Water Committee, which in turn informs the pump-minder responsible for a particular area. If the problem has not been resolved by the pump-minder, the Village Water Committee will bring this to the attention of the village Ward Councillor, who will then notify the relevant district department. UNICEF is currently funding a project where boreholes are rehabilitated by flushing. UNICEF funds are also used for the procurement of materials for rehabilitation of boreholes and for the payment of contractors involved in the rehabilitation. .

The fact that the Ministry of Health is responsible for sanitation and water quality and that ZINWA, through the District Administration offices, responsible for water supply may result in institutional confusion in terms of delineation of powers and functions with regards to water and sanitation issues. Rainwater harvesting is done on a small scale at individual homes using tanks supplied by Government or local authorities. Irrigation schemes in Southern Zimbabwe According to agriculture extension officers 677 ha of land is used for irrigation as part of six irrigation schemes in the southern part of Zimbabwe. The operation and productivity of these schemes is largely restricted by the availability of water, which in turn depends on good maintenance of the pumping equipment and water distribution infrastructure. All irrigation schemes rely on either groundwater abstracted from the alluvium associated with the major



rivers (Limpopo, Shashe and Mzingwane), or from constructed dams, for example the Zhovhe Dam in the Mzingwane River. The Government developed irrigation schemes operate on a communal basis and are exclusively for community benefit. The Department of Water Affairs is responsible for maintenance of diesel engines, pumps and other infrastructure, whereas the community pays for diesel. Seed is obtained from the Grain Marketing Board (GMB) on a credit scheme, and debt is settled by selling products to the GMB. A portion of the harvest is kept for community consumption, while the balance is sold to the GMB. Extension services and training are provided free of charge by AREX (Agricultural Research and Extension), a Government funded organisation within the Department of Agriculture. Flood irrigation is usually practiced in these schemes and implements are provided by DDF. Crops cultivated are mainly wheat and maize, and too a lesser degree vegetables for local consumption. Operational problems often encountered include diesel shortages, breakdown of engines and pumps (unavailability of spare parts), and shortage of funds.

The information on irrigation schemes listed in Table 15.3 was provided by the Department of Agriculture.

Table 15.3: Government developed irrigation schemes in southern Zimbabwe

Scheme River or water source

Total size and plot size (ha)

Crops Operational status

Shashe Shashe 120; 0.25-0.5 Wheat, maize, vegetables

~30%

Bili G/w from Shashe 21.5; 0.5 Grain, vegetables 100% Jarukanga Shashe 31.5; 0.2 Unknown 100% Chiquaraquara G/w from Limpopo 65; 0.2 Unknown Unknown

Kwala G/w from Umzimwena

90; 0.2-0.5 Unknown ~40%

Dombo Surface water from dam

5; 0.2 Unknown 100%

15.4 Conclusions In concluding this report, it should be reiterated that the scope of the research was greatly limited by the duration of the fieldtrip and that these findings should be considered preliminary in nature. Further in-depth research would greatly enhance the veracity of this initial assessment. The key findings of these visits are as follows: • Every community experienced difficulties accessing water – this could be attributed to:

o Lack of boreholes; o Costs imposed to the community; o Unaffordability of more convenient access such as yard connections; o Danmaged or Depleted boreholes as a result of poor maintenance of

infrastructure and overabstraction; o Pollution of groundwater resources acting as supply for the villages, mainly

through livestock watering and primitive sanitation systems.

• Inequity in the access to water is also created by different capacity and efficiency of different authorities as far as service delivery is concerned. In Chicualacuala, for example, civil servants and railway workers receive their water for free but community members are expected to pay for it.



• Issues of water quality were also an important finding where groundwater sources had been abandoned due to pollution resulting from sanitation . Also disturbing is the fact that in very little monitoring of both quality and quantity is taking place.

• Lack of monitoring of groundwater components and water management in general is not practiced and can have serious consequences in the long run. Implementation and managementr of schemes in a participatory way is lacking. This will go a long way in ensuring sustainability and the protection of the resource by the end users. This approach also offers the opportunities for educating the general public about issues related to the sustainable use and management of the resources. It also encourages a sense of ownership of the resource to the community.

• Governments’ ability to create and maintain water and sanitation infrastructure was very poor.



16. PROJECT COMPONENTS

16.1 Overall objectives

The overall objective of the Limpopo Basin study is to develop a strategic approach to drought management policies, focussing specifically on the role, availability and sustainable supply of groundwater resources. This strategic approach should enhance cooperation between the four countries as well as the interaction with the different stakeholders. The management procedure should further be able to reconcile the demands placed on the available resources by the different user sectors and for socio-economic development (particularly rural communities), and those of the principal groundwater dependent ecosystems (GDEs). 16.2 Methodology and approach In order to achieve the objectives described above, and based on the results obtained during the study, a number of project components have been identified. It is proposed that these components be addressed during the GEF project in order to achieve the stated objectives. The components have to be addressed in the selected pilot areas as well as on the larger basin scale. From the information collected during the study it is clear that large differences exist within the four countries of their level or degree of knowledge or understanding of the geohydrological systems in each of the four countries. It is of fundamental importance that these deficiencies be addressed at an early stage of the GEF project in order to understand the geohydrological conditions that exist in each of the pilot areas as well as a thorough understanding of the groundwater conditions within the rest of the basin. Without a much improved understanding of our current understanding of the geohydrological conditions within the area, the development and design of groundwater management plans and drought mitigation strategies will be a futile exercise.

16.3 Identified and proposed project components and activities During the Stakeholder workshop held in May 2003 a number of component categories, were presented that need to be addressed during the GEF project. It was stressed that the development of these components was objective and not budget driven. When formulating the project plan of which the identified components form the basis, there is a need to structure the plan within a dynamic framework of actions. These include aspects such as a clear definition of the resource, how this resource is to be used in a responsible and sustainable manner, the challenges that exist to exploit and manage this resource in the most appropriate way, defining strategies how to achieve the above, and finally the effective implementation and transfer of the lessons learnt into other regions within SADC.

A number of key elements that form part of this process are grouped into Major Components and then expanded into different subcomponents. The originally identified components were presented during the stakeholder workshop and were then further analysed and refined within smaller stakeholder working groups. The outcome of these discussions is captured in the summary table below. It is believed that these components all have to be addressed in order to achieve the objectives of the project and to achieve a groundwater development and management model that can be implemented effectively throughout the Limpopo Basin. Furthermore, the developed model has to be such that it can also be implemented in other drought prone areas within the SADC region by making only minor adjustments to suite more specific local conditions and requirements.



16.3.1 Component categories

The sequence in which the main categories are listed below, broadly reflects the order in which they should be studied. The categories are:

• Information • Physical • Environmental • Socio-economic • Management & Institutional • IWRM • Transboundary and legal aspects • Drought mitigation • Replication and communication within SADC • Implementation within SADC region To achieve the desired end result, a number of subcomponents were identified within each of these. These component categories were then arranged in broad “component groups” each with a set of sub-components. The subcomponents, together with a brief description of each, are also listed in Table 16.1 below.



Table 16.1: Project components, subcomponents and activities.

PRIMARY COMPONENT 1: GOVERNANCE OF INTEGRATED WATER RESOURCES (IWRM, INSTITUTIONAL ARRANGEMENTS, LEGAL CONSIDERATIONS, OPERATIONAL MANAGEMENT, CAPACITY, IMPACTS OF DROUGHT)

Objective: Ensure water resources are managed to enable the delivery of groundwater for optimal sustainable use during periods of drought. Where international water resources are involved (for example shared rivers and transboundary aquifers) practical management policies should be formulated and provisionally approved for implementing on existing water supply schemes

Subcomponent 1: Enabling agreements for regional cooperation exists Activity 1: Assessment of existing SADC and national protocols on transboundary water resource use and management. Activity 2: Formulate recommendations for the minimum conditions needed for the development of an effective protocol to achieve implementation on a local level during this project.

Subcomponent 2: Enabling agreements for national legislation exists Activity 1: Assessment of existing national legislation protocols on shared water resource use and management. Activity 2: Formulate recommendations for the minimum conditions needed for the development of an effective protocol in line with national legislation and regulations to achieve implementation on a local level during this project.

Subcomponent 3: Local (sub-catchment) management structures are in place Activity 1: Establish the institutional structures in the pilot study areas for effective water resource management. Activity 2: Establish the operational structures to implement proper water resource management in the pilot study areas.

Subcomponent 4: Operational delivery of groundwater is sustainable during drought Activity 1: Design procedures for the operational staff to enable them to monitor the delivery of water to the users. Activity 2: Develop guidelines to effectively address and rectify the shortcomings in delivery identified during monitoring



Table 16.1 (continued) PRIMARY COMPONENT 2: SOCIO-ECONOMIC CONTEXT TO MITIGATE THE NEGATIVE EFFECTS OF DROUGHT Objective : Establish the negative impacts drought has on socio-economic development and how these could be improved through the provision of an adequate and sustainable supply of groundwater at all times (including under drought conditions). Subcomponent 1: Sectoral economic vulnerability to drought and economic impacts of drought in relation to sustainable livelihoods and human development is understood Activity 1: Rank different water use sectors in terms of their vulnerability to drought. Activity 2: Analyse and evaluate the economic and other impacts of drought on different sectoral users of water in the region. Activity 3: Collect and analyse information in the pilot study areas to assess socio-economic impact of drought on the communities as due to a downturn in the economic activities linked to the drought. Activity 4: Develop indicators to assess such situations. Subcomponent 2: Optimal water provision in relation to poverty alleviation is understood. Activity 1: Determine the minimum water requirements in communities to maximise poverty alleviation during periods of drought. Activity 2: Create awareness of the economic value of water, and the cost of water and/or groundwater to generate economic benefits for example in crop production). Activity 3: Design a programme on community or village level for the development of aquifers to generate economic benefits to the community Sub-component 3: Direct (i.e. groundwater irrigation) and indirect (i.e. GDEs) dependency and beneficiation of groundwater resources in terms of social use, is quantified. Activity 1: Implement a scheme in each of the two pilot study areas to demonstrate the value of groundwater in the socio-economic upliftment of the community. Activity 2: Evaluate the output of the scheme on a continuous basis to assess the direct and indirect dependency on groundwater resources.



Table 16.1 (continued) PRIMARY COMPONENT 3: INFORMATION GATHERING, SYNTHESIS AND COMMUNICATION Objective 1: Compilation of a database of information in a suitable format for each of the two identified pilot study areas as well as the rest of the Limpopo Basin Catchment required for the successful implementation of the project. Objective 2: Provide education on basic principles of groundwater occurrence and local management thereof to raise awareness of the importance to protect and manage the resource, and to service and maintain associated infrastructure in order to ensure a sustainable supply. Subcomponent 1: Demographics, water use, supply and demand patterns, existing institutional infrastructure in the water sector. Activity 1: Compile accurate population distribution, their water use and demand patterns for the pilot study areas and Limpopo Basin Activity 2: Compile database of existing water supply infrastructure, its distribution and operational state. Activity 3: Establish accurate sectoral water use on a quaternary catchment basis. Activity 4: Carry out a resource economics-based assessment of the available information on dependence of livelihoods on surface and groundwater resources and the related ecosystem services. Activity 5: Determine and analyse the existing institutional structures and mechanisms for the supply, monitoring, maintenance, cost recovery and evaluate their operational efficiency and cost structures. Activity 6: Make recommendations for establishing and implementing effective (and if possible similar) institutional infrastructures in all four countries for the development, maintenance and operation of water supply systems, especially in rural areas. Activity 7: Compile a database on the ecological and socio-economic impacts of past droughts and the responses to them in the different countries Subcomponent 2: Physical, biological and environmental information Activity 1: Complete the geological GIS-database focusing on the geohydrologically important information (e.g. aquifer-related lithology, geological structures) Activity 2: Create and populate a database with the relevant groundwater information (expand/update existing databases of countries for boreholes, springs etc.). Activity 3: Compile a database with the relevant information on surface water resources. Activity 4: Compile a GIS-linked database of the relevant climatic data for analysis of averages, variability and long-term trends. Activity 5: Compile a GIS-linked database of the relevant and planned conservation areas and conservation priority areas. Activity 6: Compile a GIS database of the land cover and ecosystem level data on natural vegetation and fauna, focusing on potential GDEs. Subcomponent 3: Socio-economic status and requirements Activity 1: Determine the dependency on groundwater of the livelihoods of the (rural) population in the pilot study area.



Activity 2: Establish the status of issues such as efficiency of service, sustainability of water resource, cost structures, maintenance of infrastructure, response to complaints, etc. Activity 3: Determine demand for (ground) water and ability to pay for water if supplied. Subcomponent 4: Knowledge gaps Activity 1: Identify gaps in our knowledge of socio economic issues & activities Activity 2: Identify critical gaps in our knowledge of hydrological/geohydrological issues & activities Activity 3: Identify critical gaps in our knowledge of biological/ecological issues & activities. Sub-component 5: Development of functional communication framework for information sharing and decision making on national and local level Activity 1: Development of Duplication/Replication strategies to roll out results to other drought prone areas in SADC region. Activity 2: Develop and implement capacity building programmes (link to all Primary Components)



Table 16.1 (continued) PRIMARY COMPONENT 4: GEOHYDROLOGICAL, HYDROLOGICAL AND BIOLOGICAL ASPECTS Objective: To understand the geohydrological, hydrological and biodiversity conditions of the basin and the pilot study areas and their vulnerability to drought. Subcomponent 1: Groundwater potential of pilot study areas

Activity 1: Compile conceptual geological and geohydrological models for the two pilot study areas. Activity 2: Assess groundwater potential of the two pilot study areas, focusing on both shallow and deep aquifer systems. Activity 3: Identify possible areas to conduct artificial recharge experiments in order to assess its potential for drought mitigation. Activity 4: Identify potential GDEs in the pilot study areas and their likely socio-economic and conservation importance. Activity 5: Evaluate the possible impact of groundwater abstraction on the environment. Activity 6: Design and conduct a groundwater exploration programme for the two pilot study areas and identify drilling targets Activity 7: Obtain the necessary hydraulic aquifer parameters for the different aquifers through drilling and appropriate test pumping. Activity 8: Design and Implement an appropriate long-term programme to obtain reliable groundwater recharge figures. Activity 9: Establish appropriate monitoring programme and network. Subcomponent 2: Role of surface water in water supply schemes in the pilot study areas Activity 1: Assess and quantify the existing and future potential of surface water in water supply schemes. Activity 2: Design appropriate integrated water supply schemes (ground and surface water), with special emphasis on the role of each during periods of drought. Activity 3: Implement a conjunctive use scheme on a trail basis. Subcomponent 3: Impact of groundwater abstraction Activity 1: Design and implement a monitoring programme to measure and evaluate the impact of groundwater abstraction on ecosystems in a one of the selected pilot study areas. Activity 2: Establish operational structures and train staff to ensure the continuation of this monitoring after the completion of the GEF project and that proper information recording takes place. Activity 3: Make recommendations for the evaluation and interpretation of the data after completion of the GEF project to achieve maximum benefit from the monitoring.



Table 16.1 (continued)

PRIMARY COMPONENT 5: DROUGHT MITIGATION PROCEDURES AND COMMUNITY UPLIFTMENT Objective: Install/establish the necessary infrastructure in pilot areas to utilise and protect groundwater resources responsibly to ensure a sustainable supply of potable water that can be used by the communities for at least basic water requirements and food production, without impacting negatively on the environment. Subcomponent 1: Climatic drought vulnerability Activity 1: Collect and analyse all historic climatic data for the pilot study areas to establish drought related indices reflecting occurrence, severity, reasons for, etc. Activity 2: Establish possible correlations between surface water droughts and groundwater indicators (water level response, base and spring flow, etc) Activity 3: Carry out a questionnaire/interview survey of local communities to develop a better understanding of the impacts of past drought and the coping mechanisms developed by these communities Activity 4: Analyse case histories to determine the positive and negative lessons learnt from previous drought mitigation measures. Activity 5: Compile list of indicators of drought and formulate methods how these can be used to predict periods of drought, the expected severity and duration, and expected water supply situation during the drought period. Subcomponent 2: Drought mitigation using groundwater Activity 1: Identify indicators for use during periods of drought to monitor groundwater conditions and the possible impact surface water drought conditions may have on groundwater resources. Activity 2: Develop guidelines for the responsible use of groundwater during periods of drought to ensure a sufficient supply for human consumption and food production during these periods (Equivalent to a groundwater management plan for periods of drought). Activity 3: Assess the priorities of groundwater use and allocation during periods of drought.



Table 16.1 (continued)

PRIMARY COMPONENT 6: DOCUMENTION OF OUTCOME/RESULTS Objective: To capture the positive and negative aspects encountered during the project and communicate these within the rest of SADC to highlight positive features and to avoid repeating mistakes Subcomponent 1: Annual reporting Activity 1: Prepare annual project status reports Activity 2: Identify and recommend changes to the original project plan if required based on results achieved. Subcomponent 2: Final report Activity 1: Compile a final report on the project. Activity 2: Prepare guidelines for the implementation of the drought mitigation programmes based on groundwater in other regions of SADC. Activity 3: Recommend procedures to be followed for the implementation of International water resource management, with the emphasis on groundwater resources, across SADC.

Limpopo Basin Groundwater Situation Analysis - Final Report


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APPENDIX A

Terms of reference as issued by SADC



Terms of reference as specified in the contract document

1. Background The Southern African Development Community (SADC) is a regional grouping of 14 sovereign states with the main purpose of fostering co-operation for mutual benefit from the resources of this region. SADC recognised the critical importance of water to regional integration and economic development and established a distinct Water Sector in 1996, dedicated to this cause. A SADC Protocol on Shared Watercourse Systems was adopted to set the rules for joint management of the resources. A Regional Strategic Action Plan for Integrated Water Resources Development and Management has been compiled and is being implemented to address key water management issues, concerning surface water bodies and aquifers (groundwater). The region is characterised by a rapid population growth, extended drought periods followed by occasional extreme flood-events and is already highly dependent on groundwater for rural water supply and to a lesser extend for urban water supply. Groundwater is a key element for the alleviation of drought in the SADC region. However, policy responses to drought have in the past been based on short-term crisis actions, which have generally proved to be inefficient or ineffective. To address this undesirable situation proactive sustainable and integrated management of groundwater resources needs to be instituted including careful consideration of ecosystem needs. Project Objective and components The objective of the present project, “Protection and Strategic Use of Groundwater Resources in the Transboundary Limpopo Basin and Drought Prone Areas of the SADC Region” is for the SADC Member States to develop cooperatively a strategic regional approach to support and enhance the capacity of its Member States in the definition of drought management policies, specifically in relation to the role, availability (magnitude and recharge) and supply potential of groundwater resources. This will assist in reconciling the demands for socio-economic development, particularly for rural communities, and those of the principal groundwater-dependent ecosystems. The project is part of the Groundwater Management Programme for the SADC Region, which was approved by SADC Institutions and is part of the Regional Strategic Action Plan for Integrated Water Resources Development and Management. A SADC Sub-Committee for Hydrogeology provides technical back up to SADC Water Sector, and has a mandate to monitor the implementation of this programme. The current project will be developed at two levels: the regional level and the river-basin level. At the regional level, i.e. in the whole of SADC, comprising the 14 Member States, the project will identify transboundary impacts of groundwater development in the various river basins of the region, identify priority groundwater drought prone areas and provide regional management tools such as basic harmonised hydrogeological map, groundwater drought vulnerability and water scarcity maps, a minimum regional groundwater monitoring network and a regional groundwater information system. The tools developed will be applied through the SADC institutional network, which is financed by the Member Countries and through the development of a Regional Groundwater Research Institution / Commission. At the river-basin level, the role of groundwater in proactive drought mitigation will be demonstrated in the semi-arid Limpopo river basin on a conceptual level and at the field-scale in a pilot sub-catchment simultaneously taking into account applicability and replicability for the region as a whole. The location of the pilot project will be determined by the steering committee in which the four riparian countries will be represented, during the PDF B phase. It is expected that the full GEF project will carry out a groundwater resources assessment of the whole Limpopo River Basin, with particular attention given to the interaction between groundwater and surface water, to better understand the functioning of the river basin system as a unitary whole and for effective drought management response addressing human and ecosystems needs. At the sub-catchment pilot scale, the full GEF project will investigate, demonstrate and promote on the ground the



optimal uses of groundwater resources, engaging key stakeholders in a drought prone area to secure water supply for human needs and the protection of ecosystems. Project implementation A Grant has been obtained from GEF (Global Environment Facility), under the “Project Development Fund B” (PDF B), to prepare a GEF Project Document on “Protection and Strategic Uses of Groundwater Resources in the Transboundary Limpopo Basin and Drought Prone Areas of the SADC Region”, in a participatory manner. The World Bank is the Implementing agency, vis-à-vis GEF. The Objective of the preparation phase (PDF B) is to carry out a rapid, but comprehensive and critical overview of existing situation and issues related to groundwater and drought mitigation, and to propose structured project options and cost estimates for discussion. The process of preparing the GEF Project document will involve consultations among institutions in the SADC region, and at the pilot river basin: the Limpopo Permanent Technical Committee, other basin organisations and local communities in the four countries. The process will also include sourcing resources from various Cooperating Partners for the implementation phase of the project. The output of PDF B is a comprehensive project proposal to GEF. The existing SADC institutions provide an institutional framework to develop the project in terms of coordination and facilitation. Such a project would enhance regional cooperation. The Client is the Southern African Development Community and the Executing Agency is the SADC Water Sector Coordinating Unit. A steering committee has been established for the study. 2. Requirement for consultants The preparation of the GEF Project Development will be developed during a period of 18 months. The corresponding project implementation is shown in Appendix 1. It involves initial consultation of regional experts, situation analysis at regional level regarding groundwater related drought sensitivity and associated environmental stresses, situation analysis at the Limpopo river basin level, several meetings of the steering committee, a workshop in the Limpopo pilot area, and the preparation of the GEF project brief. SADC WSCU will coordinate the project activities, which require three consultancies:

1. Assistance of a Project Management Consultant (PMC) for about 5 months. The PMC will assist the SADC WSCU in particular for holding regional workshops and prepare the GEF Project document,

2. Consultancy for the regional Situation Analysis, 3. Consultancy for the Limpopo River Basin Situation Analysis and Project Inception.

The present Terms of Reference concern the third consultancy, for the Limpopo River Basin Situation Analysis and Project Inception. 3. Objectives of the consultancy The objective of the consultancy is • To carry out a situation analysis in the whole Limpopo River Basin regarding the groundwater

uses, water needs and main water related environmental issues, in the context of drought preparedness and management. The situation analysis will cover the existing available information related to the regional scope of aquifers, identification and/or ranking of drought prone areas and the actual and the potential role groundwater can play in meeting bot h human and ecosystem needs. Information on groundwater uses will encompass existing policies and incentives, such as cost of water, cross subsidies, etc., which may have an impact on volume of abstraction and water allocation to various uses, influence the projection of water use as well as the long term development and management of the resource.

• To provide background information and possible location of a GEF project pilot area. Representatives of the four riparian countries will use this information to select the exact location of the project pilot area.



• To carry out a more detailed situation analysis in the selected pilot area and develop a project concept to be discussed during a Limpopo Stakeholders Workshop. The purpose of the pilot component of the full GEF project will be to test various groundwater management options to reduce population and ecosystems vulnerability to drought. Various components of groundwater management will be investigated during the consultancy, in order to contribute meaningfully to the project elaboration. Among them are:

- Identification of major stakeholders in the pilot area, - Steps to be taken in order to carry out the mapping of groundwater drought vulnerability at the

appropriate scale, - Possible conjunctive use of surface and groundwater, - Assessment of the role shallow and deep groundwater play in sustaining the natural

vegetation in the Limpopo River Basin. - Identification of potential management issues for groundwater resources shared by several

countries in the pilot area, in view of developing guidelines for joint management and planning for awareness campaign, which may appear necessary.

- Investigation of existing involvement of water user groups and individuals (communities, farmers, town councils, industries, etc.) in management of water supply systems and water resources, as well as ecosystems protection, including groundwater. The assessment will be used to propose options and guidelines to promote community based management and stakeholders participation in groundwater resources management, during the full GEF project.

4. Expected Outputs The initial situation analysis, needs assessment and identification of relevant groups of stakeholders is proposed to be implemented during the consultancy. The successful implementation of the consultancy will provide: q A Situation Report (Interim Report) on the role of groundwater in water resources management

and development of the Limpopo River Basin, including water availability, water use, factors governing water uses and their projection in the future, such as costing, water rights and water allocation policies, water needs by different sectors including the ecosystems, rough location of drought prone areas, transboundary issues related to shared aquifers, data gaps and possible improvements. The situation analysis will gather as well views of major stakeholders regarding the exact location of the pilot area,

q Guidelines and criteria for selecting the exact location of the Pilot area presented for adoption to the steering committee of “GEF PDF B Groundwater” project, as part of the Interim Report.

q Consensus reached by the steering committee members on the location of the pilot area, q A well focused and active participation of water users groups and other stakeholders in the

Limpopo (Pilot area) Stakeholders Workshop, q Consensus reached between major actors and stakeholders in the pilot area on the main

contents of the project, q A situation report including workshop outputs on the pilot area, highlighting main issues to be

addressed during GEF project implementation and guidance on main components of the pilot phase (Draft and Final Reports).

5. Activities/tasks:

Activities will take full cognition of past experiences in each of the four SADC member States in the protection, development, management and integration of groundwater resources in drought management policies. They will also take stock of past experience of the Joint Permanent Limpopo Technical Committee and current efforts to develop joint management of water resources at the river basin scale, on going groundwater based development projects in the basin and their impact on population and ecosystems, various water related initiatives from NGOs and Cooperating Partners. The present consultancy will be articulated with other components of GEF PDF B activities. Due to the pilot nature of the project, all activities implemented will be thoroughly monitored and analysed in view of their replicability. The Consultants activities shall include:

a) Briefing from the SADC WSCU professionals and World Bank officials,



b) Reviewing relevant documentation on the project including the Proposal for PDF Block B, documents related to completed activities under the Groundwater Management Programme for the SADC region, documents related to implementation strategy and procedures of the SADC Regional Strategic Action Plan for Integrated Water Resources Development and Management, World Bank and GEF policies in the “international waters” portfolio, and other reports as shall be provided or referred to by the SADC WSCU,

c) Preparing and presenting to WSCU, within the first 2 weeks of the consultancy, a brief Inception Report giving a first assessment of existing documentation, mentioning the expected difficulties, detailing the methodology and work programme for the consultancy and identifying key critical issues in terms of project management,

d) Visit the four Limpopo basin riparian states in view of the situation analysis, collect relevant synthetic data related to groundwater availability, concurrent surface water availability, water demand, water scarcity, water resources management issues, map the panorama of water sector activities and actors. The objective at this stage is not to develop a comprehensive data set, but to prepare an overview, which can identify in broad terms the current and potential role of aquifers in the context of the whole river basin,

e) Prepare a Limpopo River Basin groundwater situation analysis, including guidelines for selection of the exact pilot area location (Interim Report),

f) Prepare a Pilot Area Situation Analysis, including stakeholders contribution from the workshop and detailing key components to be included in the GEF project preparation document (Draft and Final Report),

g) Attend and actively participate in the Regional Steering Committee Meeting (RSC2), h) Identify potential relevant participants to the Limpopo Stakeholders Workshop in the pilot area

and submit key issues to be addressed during the workshop. The consensus may need to be obtained through various forms of consultations, including separate groups meetings during the Limpopo (Pilot Area) Stakeholders Workshop, so that specific needs and concerns of various water user groups can be addressed in the most equitable and efficient way,

i) Assist in the preparation and organisation of the Limpopo Stakeholders Workshop, including preliminary stakeholders consultations and detailed planning of the workshop, with a view of securing participation of all parties involved,

j) Provide technical input and incorporate lessons learned from the Limpopo Stakeholders workshop and from other participatory techniques that will have been used, in the preparation of the GEF Project brief.

6. Expertise Required Experienced Groundwater resources experts or consultant group, are required to carry out this assignment. The consultant(s) should have qualifications in the field of hydrogeology (university degrees), have an extensive knowledge of regional aquifers, and also have experience in community based water supply management issues, groundwater assessment project elaboration, management and evaluation. The Consultant(s) should have as well proven experience in: • Surface Water resources planning and management • Natural resources and project economics • Participatory planning techniques • Environmental management The Consultant(s) must have good communication skills, experience in preparing and facilitating workshops/seminars and writing reports. 7. Duration and timing The total PDF B phase is expected to be 18 months, but involvement of the Limpopo Basin Consultant is expected to be nine (9) man-month, involving two or more consultants, to carry out the expected activities, as detailed in paragraph 5, on the basis of two main missions of about 3 months each, as shown on the schedule of activi ties, Appendix 1, Consultant Group 2.



Appendix B

Supplement to Section 10

Groundwater related environmental issues:

Descriptions of ecoregions found in the Limpopo Basin



Descriptions of the ecoregions found in the Limpopo Basin based on data from the internet site maintained by the World Wide Foundation for Nature (see WWF 2001 reference). Compiled by Dr Dave Le Maitre, CSIR, Stellenbosch (References to Tables and Figures refer to those in the main text and literature citations can be found in the main reference list.) 10.1 Kalahari Xeric savanna A small part of the upper Notwane River south of Gaborone falls into this ecoregion with its arid climate, infrequent heavy rainstorms in summer and a daily temperature range that can reach 45°C (Figure 8.6). Inter-annual variability in the rainfall in this area of South Africa is about 25% (Schulze et al, 1997). The red sands reach a depth of more than 30 m in places within the basin and are underlain by calcrete (Acocks 1998) and the rocks of the basement and karoo systems. The vegetation is an open savanna dominated by fine-leaved, deciduous Acacia species with grassland dominated by tufted grasses whose cover varies with the rainfall. Plant species richness is low. Taller trees, sometimes forming a gallery forest are found along the drainage lines of the ephemeral rivers, including Acacia erioloba, A. albida, A. karoo, A. tortilis. Surface water is rare which limits the variety of the animal life but the diversity is still quite high. 10.2 Semi-arid Kalahari Acacia-Baikiaea woodland This ecoregion covers the remainder of the Notwane catchment and the area to the north, but has a more limited range in South Africa (Figure 10.5). The rainfall is about 300 mm per year, occurs in summer and is very variable, with heavy storms of 15-90 mm within a few hours. Droughts occur on roughly a 7-year cycle. Daily temperatures may exceed 40°C and can drop below zero in mid-winter. The soils are dominated by the coarse Kalahari sands and have a low water-holding capacity. The flat topography changes in the southeast to an undulating plain formed from the ancient basement rocks and karoo sediments with abrupt hills around the towns of Mahalapye and Phalapye. The soils in this regions are finer, strongly leached and more arable than those of the Kalahari. The rivers are ephemeral and flow for only a few weeks a year and the Limpopo itself is seasonal. Deciduous tree and bush savanna covers most Kalahari sand areas. Low sand ridges are dominated by trees, including: Terminalia sericea, Burkea africana and a number of Acacia species with a shrub and grassland vegetation between the ridges. The vegetation on the remainder is a tree savanna with Colophospermum mopane, Acacia nigrescens, Terminalia prunioides, and Combretum imberbe, shrubs and tufted grasses (Cenchrus ciliaris, Eragrostis spp.). The ephemeral rivers support a vegetation similar to that of the ecoregion above. The general aridity and lack of surface water limits the animal life but the diversity, particularly of the birds, is quite high. 10.3 Southern African bushveld This ecoregion covers much of the upper Limpopo Basin in South Africa, Botswana and Zimbabwe and is bounded by the Highveld Grassland in the south (Figure 10.5). The climate is characterised by hot, wet summers and cool, dry winters. The rainfall varies from 350 mm in the Limpopo valley to 750 mm on the mountain slopes. Temperatures range from –3°C to 40°C and frosts are relatively rare. The topography is generally gently undulating and the soils are mostly coarse, sandy and shallow, overlying granite, quartzite, sandstone or shale (Low and Rebelo 1998). The Waterberg Mountains reach an elevation of 1 200 m to 1 500 m and the south-western part includes the Springbok Flats with black or red vertic clay soils.



The vegetation is savanna dominated by a mixture of species or by mopane, particularly in southeastern Botswana, southern Zimbabwe and parts of South Africa. Near Bulawayo the vegetation becomes a tree savanna (Terminalia sericea, Burkea Africana and Acacia species) with a well-developed grass layer dominated by Hyparrhenia species. The savanna of the Waterberg is characterized by Faurea saligna, Acacia caffra and Burkea africana) with Kirkia acuminata, Combretum species and Protea caffra on the rocky slopes. The Waterberg Mountains are noted for their high species richness and endemism, particularly for reptiles. The riverine vegetation is generally a species-rich scrub or gallery forest with many forest associated species (Kiggelaria africana, Apodytes dimidiata, Olinia cymosa) (Werger and Coetzee 1978). 10.4 Zambezian and Mopane woodland This ecoregion covers most of the central Limpopo basin, particularly from the Pafuri area to the Mozambique coastal plain and is notable for its diverse large mammal fauna (Figure 10.5). The rainfall occurs in summer and ranges from 450-710 mm with a few areas such as the upper Olifants catchment and mountain slopes receiving 1 000 mm. Temperatures range from -4° to 46°C with the lower elevations being largely frost-free. The elevation ranges from 200-600 m and the terrain is flat or gently undulating except in the mountains areas where the elevation reaches 800 m and 1 525 m in places (White 1983). The soils are derived mainly from deeply weathered granites and gneisses, with basalt and sedimentary rocks being important in certain areas. The texture is variable but they are generally permeable and have a high water-holding capacity. The dominant vegetation is mopane woodlands and scrub with Zambezian woodlands being less widespread. Colophospermum mopane often forms pure stands but also occurs in mixtures with other species such as: Kirkia acuminata, Dalbergia melanoxylon, Adansonia digitata and Combretum species. Mopane communities range from 10-15 m in height on deep alluvial soils to stunted, 1-3 m tall on impermeable alkaline soils. Mopane soils generally possess an impervious B-horizon where minerals accumulate (White 1983). The grass layer is dominated by tufted grasses and varies from dense in open stands to sparse in closed stands. In the eastern parts of the basin there are limited areas of Zambezian undifferentiated woodlands and wooded grasslands. The underlying rock is often deeply weathered and the soils range from sandy loams on crests, to well-structured, often sodic clays on the bottomlands, with black to red clays overlying basaltic or doleritic areas (Low and Rebelo 1998). The dense tree layer is dominated by Acacia species, Combretum species, Dichrostachys cinerea, Kirkia acuminata, Peltophorum africanum, Piliostigma thonningii, Sclerocarya birrea and Terminalia sericea (White 1983, Low and Rebelo 1998). The understorey is variable and controlled by moisture availability with Themeda triandra, Panicum maximum and Heteropogon contortus in dry areas and thatch grass species (Hyperthelia dissolute, Hyparrhenia hirta) in moister areas (Low and Rebelo 1998). The riverine vegetation ranges from woodland to a tall gallery forest, often dominated by Ficus species. The ecoregion has a species-rich and diverse fauna, particularly the large mammals, birds and reptiles. 10.5 Drakensberg Montane Grassland, Woodland, and Forest This ecoregion is found in the upper parts of Drakensberg escarpment (Letaba and Olifants River catchments), the Soutpansberg and Blouberg (Figure 10.5). The elevation generally exceeds 1 500 m and the geology is dominated by Karoo shales and sandstones with dolerite intrusions (Low and Rebelo 1998). Rainfall is about 1 100 mm and may be higher on the highest peaks. This part of the catchment is the source of the major perennial tributaries that sustain the lower Limpopo River. The soils are shallow, poorly developed, rocky and heavily leached. Cold and wet conditions pervade most of the area, excluding the Lesotho Plateau, where drought can occur in the rain shadow (Low and Rebelo 1998). Temperatures vary between –13-40°C, with frequent frosts but snow is rare (White 1983; Low and Rebelo 1998). The dominant vegetation is grassland with Afromontane forest in the valleys where



they are protected from the frequent fires (White 1983). The riverine and floodplain vegetation is grassland or low scrub or thorny trees (Acacia karoo, Ziziphus mucronata). Plant species richness generally is moderate except for the Soutpansberg and Blouberg where there are more than 100 endemic grassland species (Low and Rebelo 1998). Bird and reptile species richness is also quite high. 10.6 Highveld grassland This biome is found along south-western margin of the basin (Figure 10.5) and links up with the montane grasslands described above. The shales and sandstones of the Karoo sediments are dominant and give rise to a range of soils from deep red sandy-loams to shallow rocky soils (Low and Rebelo 1998). The mean annual rainfall occurs in summer and ranges from 400 to 900 mm. The mean maximum temperatures are mild (21-24°C), maximums can reach 38°C and minimums may reach –11°C in the winter. Frequent fires, heavy frost, and heavy grazing, originally by wild herbivores which have been replaced by cattle and sheep, suppress woody plants and they are generally confined to rocky areas and drainage lines. The vegetation is dominated by tufted and creeping grasses but there is a diverse flora of geophytes and herbs. The flat topography results in meandering rivers and extensive grass, sedge and reed-dominated wetlands (Palmer et al. 2002). The species diversity of the fauna is but the endemism is low. There are a few grassland specialist bird species that are largely restricted to this ecoregion. 10.7 Coastal forest mosaic The two ecozones that cover the Mozambique coastal plain meet at the Limpopo River, the Maputaland which extends southwards as far as Port Elizabeth in South Africa and the Southern Zanzibar-Inhambane which stretches northwards into Tanzania (Figure 10.5). Each has a complex mosaic of different vegetation types, has high species diversity and many endemic species (Moll and White 1978; White 1983). The location of the boundary near the Limpopo does not indicate a significant ecological transition in this area, it is simply a convenient and easily identifiable feature to use as a boundary. The topography is a flat coastal plain reaching a maximum elevation of about 150 m with very high linear dunes (up to 120 m) forming a belt about 5 km wide along of the coast. The Limpopo River cuts through these dunes to form a relatively narrow river mouth (SARDC/IMERCSA/ZERO 2002). The soils are formed from marine sediments deposited during periods when the sea-level rose leaving windblown, infertile sands underline in places by Cretaceous limestones. The rivers incised deep valleys which were filled with fertile alluvial material and numerous pans, swamps and vleis occur along the coast, the lower Limpopo and most of the Changane River floodplain. The annual rainfall is more than 1 000 mm along the coast but decreases quite rapidly inland to about 600 mm. The sub-tropical climate is strongly moderated by the warm water of the Agulhas current in the adjacent Indian Ocean and the humidity is generally high but evaporation rates are high. The vegetation types include forest, savanna woodland, grassland, and a variety of wetlands. The original vegetation was probably coastal forest but very large areas have been cleared during the long period of human occupation leaving forest patches and extensive secondary grasslands. Both ecoregions have high plant and animal species diversity and high levels of endemism but the Limpopo Basin only includes a very small part of this ecoregion and the species richness and endemism has not been assessed. Most of the endemics are found in the “Sand” forest on the low-lying sand plains inland of the coastal dunes. Tree species such as Cleistanthus schlechteri and Newtonia hildebrandtii are frequently dominant and there is a rich flora of vines, lianans and creepers. The forest typically occurs as patches in a matrix of open savanna dominated by Terminalia sericea, Strychnos species, Acacia burkei and Combretum molle. Acacia robusta and Spirostachys africana, Palm veld with Hyphaene and Phoenix and an open scrub with Parinari curatellifolia occur in low-lying areas with a shallow water table. Grass and sedgeland vegetation is found in areas which are waterlogged or seasonally flooded. Dune



forest forms dense thickets on the seaward side of the coastal dunes in a matrix of coastal grasslands. Ecologically important mangrove vegetation occurs on the western bank of the estuary and on both banks for about 30 km inland of the river mouth in association with saltmarsh areas. The mangroves are recognised as a part of a separate ecoregion, Southern Africa mangroves, by Olson et al. (2001) but have been grouped here because they are very limited in extent compared with the whole basin. 10.8 Zambezian halophytic This ecoregion includes the saline areas along the Changane River but most of it is found around the Makgadikgadi Pan in Botswana (Figure 10.5). It is poorly known and was not recognised as a distinctive ecosystem until recently. The climate is also semi-arid (400–600 mm per year) and the wet season is from October to April (White 1983). There was extensive flooding in March 2000 after a cyclone resulted in 500 mm of rainfall in only 3 days (UNEP/FAO/PAP/MICOA, 1998). The origin of the salt appears to be the marine sediments and possibly the underlying Karoo system. The salt has accumulated because the low-lying and flat topography results in shallow water tables, poor drainage and a lack of flushing of the salts. The communities of halophytic (salt-loving) species are scattered throughout the valley bottom and floodplain and vary from perennial wetlands to seasonally flooded grasslands. The less saline areas are dominated by grasslands with scattered patches of savanna with Acacia and Combretum species . The more frequently flooded areas are more saline and are dominated by salt-tolerant grasslands (Eriochloa meyeriana, Sporobolus nitens, Aristida adscensionis) interspersed with extensive bare patches fringed with salt marsh vegetation, particularly near the river itself. The salt marsh vegetation includes species of Arthrocnemum, Salicornia, Atriplex, and Saueda (White 1983). 10.9 Southern Miombo woodlands These occur in a very limited area of the basin between the Changane River and the Rio Save. The vegetation near the coast is a dense Brachystegia woodland with a sparse undergrowth which occurs as small patches on the sub-littoral dunes (Werger and Coetzee 1978). Further inland on the dryer sand plains (700-1 000 mm/yr) the miombo changes to a Brachystegia-Julbernardia woodland and later to a Julbernardia savanna where the rainfall decreases to 400-800 mm. The patches are interspersed in other savanna communities, thickets and mopane vegetation with palm savanna on poorly drained sites. Androstachys johnsonii dominated bushveld varies from isolated clumps to quite extensive stands in the Julbernardia savanna matrix in the dry interior of the Changane River catchment (Gomes E Sousa 1967).



Appendix C

Supplement to Section 15:

Socio-economic aspects of the two pilot study areas



SOCIO-ECONOMIC ASPECTS OF THE TWO PILOT STUDY AREAS

Compiled by the L Newton, T Masemelo and A Stephens, IUCN, Pretoria

Proposed Research Guide and Interview Schedule Protection of and strategic use of Groundwater Resources in the Transboundary Limpopo Basin BACKGROUND DOCUMENTATION Background documentation has been supplied to the researcher. These include a SADC

technical report on the basin as well as an Inception report for the project as a whole. Some basic information on the project: Client: SADC Water Sector Co-ordination Unit Project Manager: CSIR (Reinhard Meyer)

Project Context: Purpose of research The purpose of this research is to visit pilot areas and to engage with local communities about their issues related to the groundwater resource , given the aridity of large parts of the basin. This is essentially a scoping process. At this point, little is known about how many settlements are included in these pilot areas and this will unfold as the researcher accompanies the project manager, Reinhard Meyer, on his technical site visits. Expectations of the researcher – pre-trip preparation The researcher will be expected to beef up his knowledge of the basin by consulting the

Limpopo Basin technical report prepared for SADC and develop a working knowledge and definition of groundwater. This can be developed in conjunction with Meyer who is a Geohydrologist and thus an expert in the field. He should also glean as much information as he can from Meyer on any other planning initiatives that will or have had an impact on the availability of water in the pilot areas. These would include dams and irrigation schemes.

Research Methodology Given the lack of knowledge of the pilot areas and the scoping nature of the research, the

preferred methodology is semi-structured interviews with the most authoritative sources on water issues in a community. This will likely to be a tribal authority or representative and in instances, representatives from water committees. However,

Regional Strategic Action Plan for Integrated Water Resource Development and Management

Protection and Strategic Use of Groundwater Resources in Drought-Prone Areas of the SADC region

Protection and Strategic Use of Groundwater Resources in the Transboundary Limpopo Basin



all communication shall be through the most authoritative people available and it will be at their discretion with whom the researcher may interact. At no point should the researcher interact with community members before it has been cleared with the highest decision-making body and if this is not possible, then observational notes shall suffice. Observation notes shall accompany the semi-structured approach thereby corroborating or questioning respondents’ input based on what can be gleaned beyond the interview e.g. no reported problems with overstocking yet it is apparent that there is severe soil erosion.

Research Outputs Field notes typed up in a narrative style with a half page comment on key issues, points of

concern, contradiction etc. that need to be flagged. It will be the contracting party’s responsibility to write this up into a summary report. These notes shall be submitted to the researcher two days’ after the return from the field visit as there is a very tight deadline to be met.

RESEARCH QUESTIONS NB – these should NOT be answered as YES/NO questions but serve as a guide for a

broader discussion around groundwater BACKGOUND INFORMATION ON RESPONDENT(S) 1. Name(s) and Surname(s) 2. Role in community 3. Reason for being selected to participate in the interview BACKGROUND INFORMATION ON THE SETTLEMENT 1. Name of settlement 2. Estimate population and number of households 3. Ethnic group(s) and dominant languages spoken 4. Rough distribution of ages 5. Level of water services (boreholes, public taps, yard taps, house tap) 6. Level of sanitation and waste management 1. Awareness and value of groundwater Trying to establish awareness of the geohydrological cycle, the language used to refer

to and describe groundwater and what significance is attached to groundwater. A) What are this settlement’s main sources of water (rainwater, surface water,

groundwater)? If groundwater is not mentioned, probe for other sources of water. Document the language used to describe groundwater and where it is said to come from.

B) Establish whether groundwater is considered to be an important resource for this community. This would include social, economic, cultural values associated with water. Probe reasons for this response – it could be either positive or negative depending on the availability and/or quality of the water.

C) Establish whether there are any issues that affect the availability of groundwater. If not spoken about probe about impact of droughts and floods, population trends, development, commercial farming and irrigation schemes, and damming.

2. Service levels and Water Use

A) Establish how water is accessed (drawn from borehole, drawn from public tap, yard



tap, tap in house etc.). What are the satisfaction levels? Do they know of any plans to upgrade their current water access?

B) Establish how the community disposes of its waste (human and material) and what are their key concerns associated with this. Do they know of any plans to improve their sanitation and waste disposal services?

C) Establish whether the community has access to SAFE / CLEAN drinking water and what the sources of this are. If the answer is positive, ascertain what steps were taken to protect available groundwater sources. If the answer is negative, establish what the cause(s) for this poor quality of water and what steps have been taken to remedy this.

D) Determine the main uses for water (domestic use; informal economic use such as brick-making, limited mining, irrigation, livestock) and which uses are supplied through which water sources e.g. subsistence crops rely on rainfall; livestock rely on borehole; domestic use draw from spring etc.

E) Try and establish a rough breakdown of the groundwater usage ratio of domestic water use, irrigation and livestock, and informal/small scale economic activities.

3. Water Management Trying to establish to what extent a settlement manages its water resource, including

drought mitigation strategies and protection of water sources A) Establish how decisions about water usage are made in this community – this

ranges from a household level to a broader community level. This question can be initiated through the following probe “have there been in any disputes about water in this community…how was this resolved?” This would include the establishing the existence of water committees and other institutional structures and where these exist, discuss any problems associated with them. Also try to explore the involvement of women in decision-making since they are primarily responsible for domestic water use and subsistence farming. (NB: you should try to get a clear understanding of the institutional management of groundwater – particularly at a community and local level.)

B) Establish how the allocation of water is decided upon. A key question here would be “Have you ever experienced a severe water shortage?” If the answer is no, establish how the community has managed to avoid this situation. Among the issues to discuss here would be whether there is control over the number of livestock kept, whether people are only allowed to grow dry crops etc.

C) If the answer is yes, establish how the community addressed this situation. Answers here would include ‘cut back on livestock and relied on game meat for protein’, ‘reduced number of crops that required irrigation’. You may well find that a community may have been aware that it was running short of water but continued its normal usage of water because there were no livelihood alternatives. This may be the case in areas where locals are no longer able to source game meat as a source of protein and where poverty levels are very high.

4. General

A) Establish whether communities have any general concerns about water, in terms of water availability, access to water, supply, etc.

B) Establish whether the community is satisfied with their access to and use of water in general. Ask for explanations and reasons around yes / no answers.

OBSERVATIONS The researcher should complement the above questions with broad observational notes

taken in the communities visited including but not limited to the following:



• socio-economic issues in the communities; • environmental issues in the communities; • factors that corroborate or dispute answers to the research questions; • water in the communities visited – pollution, supply, sources, etc

protection and strategic uses of groundwater...

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