volta basin 2030: needs, opportunities and risks
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This was presented at the Basin Focal Project Review meeting held in Cali, Colombia from 1-5 Feb, 2008TRANSCRIPT
V lt b i 2030Volta basin 2030:Needs,
opportunitiesopportunities and risks"
Cali February 2008
Volta BasinVolta Basin area : 395 000 km2
Burkina Faso Population (2007)20 M
Burkina Faso
Data mainly from Ghana and Burkina Faso
Ghana
Burkina Faso,
The Volta basin : 6 countriesCali February 2008
Dissemination pathway
Government :Within basin
Outside the basinGo e e tRelevant Ministries, Departments
BFP VoltaOutside the basin
Scientificcommunity
and Agencies (MDA)
Di t i tInstitutions for
CPWF
District assemblies
TraditionalDonors bilateral
water management at basin scale
VBATraditional Heads (Chiefs)
Development
bilateral,international
VBA
ECOWAS-WRCUDevelopment agencies
Farmers/Water
NGOsWRC x 6
VRA Ghanausers associations
Cali February 2008
WaterWater
Water productivity
Water and poverty
P t FoodPoverty Food production
Institutions
Cali February 2008
Scale : the basin time : present and trends 2050
The challenge (1)
Volta basin
Pop. ( x106)
Starchy foodproduced
Starchy food needed basin
Year
( x10 ) produced(kcal x 1012)
needed (kcal x 1012)
Year2005 19.5 21* 172025 32 ? 282025 32 ? 282050 50 - 60 ?? 48
plus possible climate change impact
Cali February 2008
The challenge (2)The Global scenarios for SSA to 2050 (SRES and Millennium Assessment ) :
• the demand will not be matched by an increase in domestic agriculture production,g p ,
although• higher levels of agriculture productivity growth • higher levels of agriculture productivity growth
compared with north western regions,• the relatively lower level of productivity from which
SSA i i t ti l i h f thi diffSSA region is starting explains much of this difference.
Cali February 2008
Two main prioritiesTwo main priorities
The rain fed food crops in the semi-arid area
The water uses in the basin
Cali February 2008
The rain fed food crops in the semi-arid areap
present distributionyields yields water productivity
l t i f d d tirural poverty in food crop productionin fisheriesin livestock productionp
the ways out of poverty: diversification (small scale irrigation )diversification (small scale irrigation ..)intensification (...)
Cali February 2008
Food production
Rain fed = 99 % of total cultivated area
Main cropping systems
CerealsCerealsmilletsorghummaizerice
Rootcropsyamcassava
plantain
Cali February 2008
( data from MOFA and MAHRH)
Th li iThe agroclimatic zones and rainfall
-SahelSahelo sudan-Sahelo-sudan
-Sudan-Guinean
Cali February 2008
500 - 900 mm 900 - 1100 mm > 1100 mm
Cali February 2008
% of cultivated area for the different crops along theclimatic gradient
The increase in production results from increase in cultivated area,not from increase in productivity.
Cali February 2008
p yData for the Ghana and Burkina parts of the basin, 1992-2004.
The cropped areaThe cropped areaas % of total land
Cali February 2008
2,5Y Maize (t/ha)
1 5
2
1
1,5
0,5
0400 900 1400
Rainfall (mm)
Production data from Ghana and Burkina Faso, 1990-2002,rainfall from CRU
Cali February 2008
rainfall from CRU
WPr maize kg/m30,4
0 2
0,3
0,1
0,2
0,0
,
Rainfall (mm)
400 900 1400
Cali February 2008
Y millet t/ha2
2,5
1,5
2
1
0,5
Rainfall (mm)
0400 600 800 1000 1200 1400 1600 1800
Cali February 2008
0 4WPr millet kg/m3
0,3
0,4
0,2
0,3
0,1
0400 900 1400 1900
Rainfall (mm)
Cali February 2008
An analysis of rural poverty in Burkina Faso y p y
data from TASIM-AO project
3 regions, 6 villages in each30 households in each
The study was based on the food sales from theThe study was based on the food sales from the Households in order to evaluate the inland market possibilities
The results are by quartiles of the total, plus the upperdecile
Cali February 2008
Poverty incidence in Ghana Burkina FasoBurkina Fasoand Togo
Cali February 2008
Cumulated cultivated area as a function of the householdCumulated cultivated area as a function of the household sales. The three lower deciles cultivate 10 % of the land, while the
d il l i 30 % f h l dCali February 2008
upper decile cultivates 30 % of the land
From Q1-Q2 to Q3-Q4
Total sales +++area +++Water/irrig ++Family manpower ++Family manpower/ha --Hired manpower days/ha +++Hired manpower days/haInorg. fertilizer % ++Draught power % ++Draught power number ++Cattle +++Small ruminants ++Small ruminants ++Credit use % +Family credit % ++
Cali February 2008
Institutional credit % +
Total sales ( CFA )2
1 2
1,63000 USD
0,8
1,2FadaKayaDédougou
2000 USD
0
0,4
area (ha)
1000 USD
00 5 10 15 20
( )
Cali February 2008
InorgFertilizer(% of farms)= f(ha)
75
100
50
75
FadaKaya
25
h
Dédougou
00 5 10 15 20
ha
Cali February 2008
The main constraints to the increase of production for food sales (from TASIM-AO, 2005
PN5 experiments Northern Ghana
16001800
100012001400
g/ha No fertil.
600800
1000
Yie
ld k
g
Micro-doseFull dose
0200400
Effects of fertilizer on crop yields central Volta basin
0
Maize Millet Sorghum
Cali February 2008
Effects of fertilizer on crop yields, central Volta basin(from CPWF PN5)
M d li f tili i t i ldModeling fertilizer impact on yields and water productivity
Cali February 2008
Out of poverty Household water d l ff d bl t dHousehold water develop affordable access to good quality (health etc.)
Intensification = better use of rainfallIncrease power, tools, land, yield, decrease vulnerability
draught animals, plough or cart,g , p g ,fertilizers, SWC, rain harvesting (PN47)
Diversification small scale irrigation (dry season), large scale irrigationg gcash crop, small ruminants, cattle,processing ( fish, beer ...),
Cali February 2008
fishing ><cultivation
Lack of access to good qualitygood qualityhousehold water
The two darker fzones are for more
than 60 % without good access
Cali February 2008
Water related diseases : a significant limiting factorThe example of malariaThe example of malaria
High prevalence over whole basin,g p e a e ce o e o e bas ,
Health system very expensive and poor efficiency
Prevention not affordable ( > 1 USD/day)
Malaria as cause of 30 % of micro credit failure(Planet Finance), and concern at macro economic state scale
Technical solutions exist (ACT, mosquito net, maternal prevention) but poorly applied.
Cali February 2008
Basin wide malaria prevalence model(from MARA/ARMA(Program)
From environment,pop density rainypop density, rainy season,...)
10% classes
To be compared withcultivated area %
Cali February 2008 Volta BFP
Three main activities
Cultivation Livestock Fisheries
Similar status for the poorer : lack of productionSimilar status for the poorer : lack of production means and poor labour efficiency
FisheriesSocial and economic importance of fisheries for thebasinbasin
Livestock S ll i t f t t fSmall ruminants as safety net for many,Intensification needed, with improved use of fodderPresent and future export value.
Cali February 2008
p
Out of poverty
Intensification ( = better water productivity)Intensification ( = better water productivity)
f
Small farmer fisherman
Incentives and credit as for cotton development = political willWith nation wide benefits for the people now andWith nation wide benefits for the people now andlater
- Large inland market, - land tenure, market access, inland market development,
Cali February 2008
Water productivity
The general approach, at the field scale,
WP = production/water consumed by the plantsWP = production/water consumed by the plants
Grain , biomass Soil evaporation + evapotranspiration
In rain fed agriculture, the agro-climatic regions determine where specific crops can be grown. The p p gfield needs a certain amount of rainfall.With a farmer or ecological perspective, rainfall WPis chosen as a tool to measure improvement of ais chosen as a tool to measure improvement of a system (Gregory 1988 in Rockström & Barron 2007).
WP d ti / i f ll i d b th fi ldCali February 2008
WPr = production/ rainfall received by the field
Water uses in the basin
The surface water resourceThe underground waterSurface water allocationSurface water allocationOpportunities:
irrigation, small scalei i ti l lirrigation, large scalehydropowerVolta basin Authority
Risks : climate changeenvironmental flows
Simulation : two scales• whole basin and Lake Volta
b b i d ll i ( d f t Cali February 2008
• sub-basin and small reservoirs ( need for recent data)
Where does the water go ?the water go ?
Mostly in the air,
Runoff coef. (3 -12 %)
Cultivated areaCultivated area= (13.7 % of total)
= most of evap. not from cultures
Irrigation < 0.1 % of total area
Undergroundxx
Cali February 2008
xx
Many of the rivers of the Upper Volta basin used to dry up during part of the yeardry up during part of the yearbefore 1974.
Some have become perennialSome have become perennialafter the construction of hydro-electric reservoirs.
Data from Moniod et al. 1977
Cali February 2008
Lake Volta : a major component ofa major component of the aquatic system
8500 km28500 km , about 140 km3 (three yearsresidence time),and uncertainty about ythe fisheries productionCirca 70 000 fishermen
Ghana Togo
Fishing = diversification
from MODIS data base
Cali February 2008 Volta BFP
Observed inflows to Lake Volta (1985-99)
6070
(km
3)
y = 0 36x - 10730405060
Lake
Vol
ta
y = 0,36x - 107R2 = 0,66
01020
nflo
w to
L
200 250 300 350 400 450 500
Rainfall on basin (km3)
In
Observed inflows to Lake Volta as a function of annual rainfall on the basin. Data from Volta River Authority and CRU.Mean inflow : 36.7 km3/y Mean runoff coef : 9.3 %
Cali February 2008
10% change in rainfall = 39 % change in inflows
Two questionsq
• What would be the impact of rainfall change on the availability of water for electricity production ?y y p
• What relationship between small reservoirs development and water inflows to Lake Volta ?development and water inflows to Lake Volta ?
The approach :
A simulation combining river discharge (from Mac Kirby) and WEAP for water uses and ( y)allocation
Cali February 2008
Plus 1 °
ITCZ latitudinal shiftdand
rainfall changes
Minus 1°1980-2000
Cali February 2008Our climate change scenario
Domestic 156
Livestock 71
Irrig. various 242
Large dams 630
Small reservoirs 894Small reservoirs 894
Lake Volta 35000
Basin wide main water uses 1996-2000Cali February 2008
Basin wide main water uses, 1996-2000
Akosombo dam and spillway In March 2007 only 2 ofAkosombo dam and spillway. In March 2007, only 2 of the 6 turbines were working, and only one in June
Cali February 2008
50 000
60 000 ReferencescenarioWetter scenario
40 000
50 000 Wetter scenario
Drier scenario
20 000
30 000
10 000
20 000
00 2 4 6 8 10 12 14 16 18 20 22
Year of simulationInflows to Akosombo as simulated by WEAP in the three scenarios. The main variability remains dependent on the year to year rainfall
Cali February 2008
The main variability remains dependent on the year to year rainfall variations.
140 000
160 000Storage capacity (148,000 Mm3)
100 000
120 000
m3)
60 000
80 000
Stor
age
(Mm
Top of inactive (70,000 Mm3)
20 000
40 000
S
Reference scenario
Wetter scenario
D i i
Top of buffer zone (85,000 Mm3)
00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Year of simulation
Drier scenario
But on the long term, there is a progressive increase or
Year of simulation
Cali February 2008
decrease in water availability
Small reservoirs development ( see also PN47)There is a strong demand for ne small reser oirsThere is a strong demand for new small reservoirs
Present total storage in 2007 is estimated from our calculations as 900 Mm3 for 1600 reservoirscalculations as 900 Mm3 for 1600 reservoirs.
Th d l d d f h h b iThe model needs more recent data for the northern basin, because of the hydrological paradox :
In dry periods ( post 1972) the runoff coefficient hasIn dry periods ( post 1972) the runoff coefficient has almost doubled compared with the wetter period (pre 1972) in the basin with a rainfall below 750 mm/y. In Wayen, the coefficient changed from 1.4 to 2.8
Another approach indicates that the volume of the i i b t t d f th fl t L k V lt
Cali February 2008
reservoirs is substracted from the flow to Lake Volta.
Outputs of BFP Volta
Portofolio of research and development activities for VBA, UCRE, funding agencies, NGOs and technical ministries :
- underground water resource,- institutions changes for land tenure, investment- livestock (transhumant) status enforcement, ( )- bush fodder,- weather forecast (AMMA) and practical use,- fisheries monitoring (how) and improvement,- further developments of allocation model within climate and population change, at different scales,addressing local and transboundary issues,
More on social acceptance/enforcement
Ouagadougou November 2007
Water availability:
Climate change (past and future),
Rain season variability and forecastRain season variability and forecast,
Surface/underground resource and variations f ti f l d d l das a function of land cover and land use,
Impact of reservoirs on the water availability p yand transnational agreements
Water budgetWater budget.
Socio-economic analysis of hydropower generationd ith th tcompared with other water uses.
Ouagadougou November 2007
Agriculture : - soil and water conservation techniques *- soil and water conservation techniques
(cost in labour, e.g. zaï only on most degraded soil andhigh pop density, 1.5 % of cultivated area),
f tili i i- fertilizer use, socioeconomic
- groundwater use
- irrigation potentialDevelopment of small reservoirs for small irrigationDevelopment of small reservoirs for small irrigation. Social management of large schemes
W t lit lt f ti idWater quality as a result of pesticides..
Ouagadougou November 2007
Volta basin institutions (1)D l t ithDual system with
Legal state and traditional hierarchyg ylow enforcement power land tenure and
water access
conflicts use one against the other
P i hift f l d t t th th ??Progressive shift from one land tenure to the other ??
= the poor maintained poorinsecure land tenure, small investment on water and soil conservation techniques or fertilizers
Ouagadougou November 2007
Volta basin institutions (2)
Health system to be improved, by capacity building and public awareness,
Basin scale Volta basin Authority being created, and WEAP for water allocation between power generation and irrigation
Market access, for cash crops (eg cotton) and meat, and in-basinmarket development for food crops.
Ouagadougou November 2007
Dissemination pathway
Government :Within basin
Outside the basinGo e e tRelevant Ministries, Departments
BFP VoltaOutside the basin
Scientificcommunity
and Agencies (MDA)
Di t i t meetings
CPWF
District assemblies
TraditionalDonors bilateral
meetings
VBATraditional Heads (Chiefs)
Development
bilateral,international
VBA
ECOWAS-WRCUDevelopment agencies
Farmers/Water
NGOsWRC x 6
VRA Ghanausers associations
Cali February 2008
Thank youThank you
Cali February 2008
The uneven distribution of towns and population densityin Ghana and Burkina Faso
Cali February 2008
Rural PovertyyWhy
Water relatedPoor water productivity (yields)Poor water productivity (yields)Rain fed dominance, rainfall quantity and variability risk avoidance low yieldshealth (malaria), domestic water (diarrhea) human power ( ) ( )decreased low yieldsaccess to water for livestock conflicts
Non water relatedPoor soils, degraded soils, Low work power
Institutional,Land tenure access to water micro credit not for agricultureLand tenure, access to water, micro credit not for agriculture, cash crop market low (cotton), access to fertilizers, Why?Solutions and techniques available but lack of implementationSolutions and techniques available but lack of implementation
Cali February 2008