integrated water resources management in nigeriaintegrated water resources management in nigeria...

Integrated Water Resources Management in Nigeria

Hadejia-Jama’are Komadugu Yobe Basin (semi-arid north)Cross River Basin (humid south)Bart J.M. Goes (goebt@hotmail.com), IWRM ProjectPresentation for ‘AH K’ Hydrologists, Free University, Amsterdam, Netherlands April 8th, 2010

WATER SUPPLY AND SANITATION SECTOR

REFORM PROGRAMME(WSSSRP)

European Union Federal Republic of Nigeria

Content1) Introduction

Nigeria, Yobe and Cross River basins

2) Hadejia-Jama’are Komadugu-Yobe Basin: overview, regional IWRM issues

3) Institutional structure in water sector4) IWRM Project for Yobe Basin5) Groundwater management Damaturu6) Impact of dams on river flow

Zuma Rock, near Abuja (capital)

1 Introduction to Nigeria

Yobe and Cross River basins (basins in which IWRM Project works)

Attributes HJK Yobe Basin (Nigeria) Cross River Basin (Nigeria)

Surface basin [km2] ~179,000 ~59,000Population (106) 15-20 10-15Ethnic groups ~2 ~9Rainfall (mm/y) 350-1,300 1,000-3,500Mean river flow (109m3/y) ~4.5 50-60

River flow controlled? Yes (2 dams, 1 proposed) No

Formal irrigation [ha] ~20,000 ~1,000Hydrogeology Basement Rock (~35%),

sedimentary (~65%)Shales (~60% ), Basement Rock (~15%)

Groundwater issues Level decline sedimentary, shallow pollution

Borehole siting in shale dominated areas difficult

States/provinces 5 (+4) 8 (+1)

River Basin Development Authorities

2 3

Basin wide stakeholders forums? yes no

Yobe and Cross River basins compared

Yobe River (Geidam)

2 Hadejia-Jama’are Komadugu Yobe Basin

Intro HJKY Basin – elevation & rivers

Intro HJKY Basin – rivers

Intro HJKY Basin – annual river flow (106 m3) &geological boundary

Jama’are River in upstream Basement Complex area during wet season (draining river)

Jama’are River (Bunga Bridge) during dry-season

Intro HJKY Basin – river water uses:(in)formal irrigation, urban, Ramsar site, floodplain

Surface water intake (6) Kano City downstream of Challawa Dam in dry season, provisional bund in river to raise water level for intake

Wet-season flood rice farming Hadejia-Nguru Wetlands (Gashua)

Fishermen in Hadejia-Nguru Wetlands (Likori)

Informal rice field irrigation from Yobe River (near Damasak)

Hand dug watering hole for cattle in Lake Chad area (Kwarildem)

Regional Water Management issues HJKY Basin

WM Issues HJKY Basin – decline in river stage data

Regional water management issues HJKY Basin(or ‘triggers’ for IWRM)

• surface water demands exceeding mean river flow • river channel blockages hampering the flow of water to

downstream users• impact of large upstream dams• groundwater level decline in certain parts of the basin• potential impact of a new large dam (construction on hold)• decline in hydrometric network• little/no attention for groundwater data & management• a complex institutional structure in the water sector

3 Institutional structure in water sector

Stakeholder Consultative Forum on HJK Yobe Basin, Kano 21-22 May, 2009

Institutions – 2 River Basin Development Authoritieswater regulator (dams operation) & water user (large irrigation projects)

Institutions – 5 (or 8?) States each with: a) Ministry of Water Resources, b) Water Board/Cooperation, c) RUWASA, d) Ministry of Agriculture, e) Agricultural Dev. Programs

Other organisations on Water Management in the basin

• HJK Yobe - Trust Fund: implementation of WM measures 2007-11 (financially supported by 6 States & Federal Gov.)

• Donor supported projects (DFID, EU, IUCN)• Stake Consultative Forum = IWRM in practise but:

a) no legal statusb) no budget (depends on donors) c) leadership needs strengthening

Institutions – proposed reform under Water Resources BillRiver Basin Development Authorities Irrigation Management Authorities (water user)

Institutions – proposed reform under Water Resources Billone River Basin Management Commission (surface and groundwater regulator)

4 IWRM Yobe Basin Project

A day at the office (IWRM Yobe Project , Damaturu)

Integrated Water Resources Management – IWRMsome key principles

• manage water according to hydro(geo)logical boundaries• involve all stakeholders• separate water regulator from water user• address both surface and groundwater• take into account the environment• water resources database as a basis for informed water

management• IWRM requires ‘triggers’ or regional water issues

Situation at start of IWRM Project

Original Project plan was a bit outdated:• Planned support to River Basin Management Commission not

possible because delay in acceptance of National Water Bill• Many water plans already available for basin, why develop a

new one?• Rehabilitation hydrometric network already ongoing (TF, IUCN)

Sustainability: how to make a long-term impact with a short (~1.5 years) Project?

Making IWRM building blocksActivities that will hopefully still be useful after 5 years :1. Capacity building (counterparts & trainings)2. Complement hydromet network activities (e.g. ‘ADCP’ for

river flow, ‘divers’ for groundwater level)3. Database development & sharing (river flow, groundwater

pilots, formal irrigation projects, ..)4. Examples of data analyses for water management5. Upgrade existing (IUCN-HNWCP) river flow and water

uses model for informed planning 6. Institutional strengthening (Trust Fund, Stakeholders

Consultative Forum)

Yobe river flow database: 51 stations with number of years (850 data years in total over period 1958-2008)

River gauging – Acoustic Doppler Current Profiler

Use of river gaugings – river stage into dischargeBunga Bridge - Jama'are River (downstream of Kafin Zaki, proposed dam site) - Rating Curves

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0 200 400 600 800 1000 1200 1400

River Flow [m3/s]

Riv

er L

evel

[m]

river gaugings 1993-1994 curve 1995-1998 curve

1995-1998 rating equations: (1) H>0.5 & H=<7.7 Flow = 4*(H-0.5)^2.5(2) H>7.7 Flow = 1.55*(H-0.5)^2.98 H = river level

Outcome of ADCP River gauging – Gashua

Outcome: detailed 2D velocity profileTotal discharge4 profiles in ~30 minutes

Pilot groundwater databases: Yobe & Cross River

5 Groundwater management Damaturu

Damaturu, water vendors filling water carts from underground tank near borehole

Pilot groundwater databases Yobe – locations

Overview of groundwater work

• Means: building and analysing a database• Partners: Yobe State Ministry of Water Resources,

Water Board, RUWASA and UNIMAID• Database building: fieldwork on water quality,

GPS, water level (~4 weeks), search archives (pumping tests, litho logs, etc.), data entry

• Data analyses: GIS maps, water balance calculation, reporting

Pilot groundwater database Damaturu: 223 water points

Pilot groundwater database Damaturu: water uses

Public water supply Damaturu

• Attributes public boreholes: 4 l/s, 6 hours pumping per day, 40% transmission losses in water supply

• The ~87 existing public boreholes are enough for basic water supply of the ~ 100,000 inhabitants (40 l/d)

• Still >50% of population depends on commercial water vendors because: i) half of public boreholes not active (maintenance, delayed commissioning, diesel for pumps), ii) poor revenue generation (metering), iii) large private underground tanks hamper equitable piped water supply

Large private underground tank taking all public water

Pilot groundwater database Damaturu: aquifers

Pilot groundwater database Damaturu: fluoride map

Attributes of high (>1.5 mg/l) Fluoride pointsFluoride [mg/l]No data 125<1.5 931.5-5 25-10 2>10 1Total 223

• In eastern and northeastern part of Damaturu• Deeper boreholes in ‘Chad-B’ aquifer (90-160 m-bs)

Relation with other elements• Fair relation: high: Ph (8-9), low: Ca (≤10 mg/l), hardness

(≤25 mg/l), NO3 (≤2.5 mg/l), Mn (≤0.2)• No/unclear relation: EC, Na, Mg, K, Cr, Cl, SO4,

Fluorite mineral dissolution: CaF2 ↔ Ca2+ + 2F-

So dissolution generally takes place when low [Ca2+] Solution? Reduce [F-] by increasing [Ca2+] (e.g. add gypsum) (based on Appelo & Postma, 2005)

Pilot groundwater database Damaturu: summary map

Diver installation

for automatic

groundwater level

monitoring

Releases from Challawa Dam into Hadejia River System

6 Impact of dams on river flows

Data analyses - impact of dams on river flow

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Cumulative annual flow at Bunga [109m3]

Cum

ulat

ive a

nnua

l flo

w at

Wud

il [10

9m3]

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......

1964-73 (pre-Tiga Dam): Wudil = 0.95 x Bunga (R2=99%)

1979-89 (post-Tiga Dam): Wudil = 0.64 x Bunga + 6.8 (R2=100%)

1974-78: filling up of Tiga Reservoir

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1989

Data analyses - impact of dams on annual river flowCumulative annual flow Bunga (uncontrolled) versus Wudil (controlled)

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Cumulative annual flow at Bunga [109m3]

Cum

ulat

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annu

al fl

ow a

t Had

ejia

[109

m3]

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......

.

1964-73 (pre-Tiga Dam): Hadejia = 0.34 x Bunga

1979-90 (post-Tiga Dam): Hadejia = 0.37 x Bunga - 1.03

1974-78: filling up of Tiga Reservoir

(R2=100%)

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1973

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1990

Data analyses - impact of dams on annual river flowCumulative annual flow Bunga (uncontrolled) versus Hadejia (controlled)

Data analyses – river flow reduction Wudil-HadejiaFlow arriving at Hadejia (downstream) given flow at Wudil (upstream)

Data analyses - impact of dams on dry-season river flow

Data analyses - impact of dams on dry-season river flowDaily flow Hadejia 1967/68 (pre Tiga & Challawa Dams)

Data analyses - impact of dams on dry-season river flowDaily flow Hadejia 1995/96 (post Tiga & Challawa Dams)

Data analyses - impact of dams on dry-season river flowAnnual & dry-season flow Hadejia 1964-2001

Consequences of unnatural dry-season flows

• Channel blockages because: a) river beds no longer dry out so Typha and other weeds get water all year round, b) reduced peak flows to flush the channels

• Excess water in Marma Channel• Minimal contribution from Hadejia to Yobe River• Waste of water especially in second half of dry-

season

Consequences dry-season flows – Hadejia-Nguru Wetlands

Weed blockages in lower Burum Gana River, dry season

Excessive floods Hadejia-Nguru road near Marma Channel, 2005 wet-season

Thank you for your attention

Repairing a puncture on a cart of a water vendor, Damaturu