Groundwater Rational Use To Enhance Urban Water Security .

AfWA Conference, Bamako, Mali, February 2018Governance and institutional framework sessionGroundwater – rational use to enhanceurban water security under global changeLead researcher: Dr. Stephen Foster, IAH past Pres. and , visiting Pr., University College LondonDr. Sean Furey, Swiss Resource Centre & Consultancy For DevelopmentDr. Anne Bousquet, Regional Coordinator for Africa and Asia, GWOPA-UN-Habitat

OUTLINE OF THE PRESENTATION1) Introducing UPGro2) Water security and ground water resourcesConcept of water securityRole of groundwater in water security3) Self-supply boom – current trends in use of ground waterUrban growth unprecedented and growth of water demandTypical “supply” responseAfrica regional evolution of type of supplyCauses and consequences of the self-supply boom (Rich and Poor people)Advantages of using groundwater resources for the utilities/ water security4) How to enhance water security through ground water useExample of conjunctive use of ground and surface with loop of reuseWhat should be done to optimize use of ground water in the utilities’ perspective (to enhance source security)Mapping the sources of pollution of the aquifers (Risks and hazards assessment)What should be done to regulate and optimize; policy implications, role of the utilities

1) INTRODUCING UPGroUnlocking the Potential of Groundwater for the Poor (UPGro),7 year international research programme (2013-2020)Focus on improving the evidence base around groundwateravailability and management in sub-Saharan Africa (SSA) toenable developing countries and partners to use groundwaterin a sustainable way in order to benefit the poor.UPGro Knowledge Broker charged with facilitating the uptakethe research findings into policy and practice.

4Diverse groundwaterGroundwater storage(Source: MacDonald et al, 2012)2012: firstquantitativecontinent-widemaps of aquiferstorage andpotential published 0.66 million km3of storage (not allavailable forabstraction)

6The Consortium Projects (2015-19)GrofuturesHidden CrisisWorking in Benin, Burkina Faso,Ethiopia, Ghana, Kenya, Malawi,Niger, Nigeria, South Africa,Tanzania, Uganda research commissioned onground water use and urbanutilities Stephen FosterUpgro.org

2) WATER SECURITY AND GROUND WATER RESOURCESDEFINITION ‘Availability of an acceptable quantity and quality of water forhealth, livelihoods, ecosystems and production, coupled withand acceptable level of water-related risks to people,environments and economies’*. The ‘scale’ issue – use at national level too nebulous better when referred to specificcity (or basin) and to a specific function (like water-supply)** Urban water-supply security assessed in terms of:accessibility – in effect availability and continuityaffordability – cost especially for lowest income quintileacceptability – safety as regards qualitysustainability – susceptibility to decline/vulnerability to pollution*Grey & Sadoff, 2007 ** Foster & MacDonald, 2014

ROLE OF GROUNDWATER IN WATER-SUPPLY SECURITYvast stocks (storage) but modest fluxes (flows)Predominant form of global freshwaterstorage95-97% of ‘circulating freshwater’ groundwater – but only 0.03 % of‘groundwater stock’ replenished annuallyVery large storage means subsurface‘residence times’ large and ‘aquifermemories’ long (decades to millennia)high microbiological and chemical qualityBut any pollution can be very persistentand remediation problematic

3) SELF-SUPPLY BOOM AND CURRENT TRENDSUnprecedented growth in urban population andwater demand, especially West Africa

TEMPORAL GROWTH IN URBAN WATER DEMANDwith typical supply-side response

EVOLUTION OF WATER-SUPPLY SOURCES IN AFRICAN CITIES: ACCESSIBILITY AND AFFORDABILITY *Regional average urban water-supply s/dugwells)STAND-POSTSSURFACE 5-20002000-2005Regional average urbanwater-supply affordability* Sources: World Bank AICD Foster & Briceño-Garmendia, 2010, and Banerjee et al, 2017

GROUNDWATER USE IN SELECTED AFRICAN CITIESdata for sometime in period 2011-2015CATEGORYOF CITYWater Utility with MajorGroundwater DependencyAbidjan **UTILITY GWUSE (Ml/d)(propn)285 (100%)UTILITYSERVICELEVELmoderatePRIVATEGW USE(Ml/d)some #Dakar **210 (70%)excellentminor #50 (80%)excellentminorDodoma **45 (100%)goodminorKabwe40 (100%)goodminorN’Djamena **35 (100%)poorsome #120 (40%)*moderateminor #CITYArushaWater Utility withConjunctiveResource UseAddis AbabaWater Utility withPoor Service Levels& Major PrivateGroundwater Use*Dar-es-Salaam30 (10%)*poormajorBenin City45 (50%)poormajorNairobi30 (5%)moderate80-240 #Lusaka135 (45%)moderate100-300Mombasa80 (100%)poormajormajor new groundwater source under exploration/development** modern supply system deploying external wellfield(s)# cost constructing/equipping private water borehole US 10k

CAUSES AND CONSEQUENCES OF THE SELF-SUPPLY BOOM (RICH AND POOR PEOPLE) Coping strategy’ for confronting poor water-utility service coverage and/or reliability High cost of constructing/equipping water-supply boreholes means only affordable byhigh-income quintile Poorer households have to resort (where feasible) to shallow handpump dugwells withpoor sanitary completion which are more vulnerable to pollution Private borehole use likely to be perpetuated long-term as cost-reduction strategy Massive private domestic self-supply reality – can distort utility water operations withmajor implications for finance/investment Open-access to groundwater cannot be regarded as ‘pro-poor’ since reduces revenue ofwater utilities Could be regarded as reducing demand on (and recovering leakage from) utility watersupply and very good practice for ‘secondary uses’ ‘Banning’ such practice too simplistic (unrealistic and impractical), except where it posesmajor public health or environmental hazard Need for systematic study of hydrogeologic dynamics, engineering economics andsociologic impact (only limited work in districts of Accra, Lusaka & Lagos)

WHY TAPPING INTO THE POTENTIAL OF GROUND WATER RESOURCES allow phased investment in supplyexpansion at much lower capital cost(avoiding advanced treatment) suitability located and constructedgroundwater sources provide supplysecurity against drought and pollution basis for providing a high level of watersupply reliability and continuity but requires proactive involvement inresource management and qualityprotection

4) HOW TO ENHANCE WATER SECURITY THROUGH GROUND WATER USERecommendations on management ofthe aquifers:Enhance recharge, reduce pollutionload, improve construction standardsfor private wells and in-situ sanitation,advise users on potential hazards,charge or regulate groundwater use(?)Su st ainab ley ie ldM ixed st rat e g yLim i tab st ract io n s t on o m o re t h ant h e l o ng - t ermaverag erech arg e.Pla nn edd ep let i on f o r ali m it ed p erio df ol lo w ed b yab st ract io n ata su st ai nab l erat e.M in in gLo ng - t ermp ro g re ssived ep let i on ,red u cin g t h eg rou n d w at errese rve s o vert im e .W ell/Bo reho leSo il andun sat ur at edro ckRenew ableGro un dw at er‘Fo ssil’Gro un dw at erW at er levelaf t ersust ainedp um p in g“Li vi ng of f t h ein t ere st o rearn in g s”“Sp en d in g so m eo f t h e savin g sf ol lo w ed b y livi ngo ff t h e in t erest o rearn in g s”“Sp en d i ng t h esavin g s”

UTILITIES’ INVOLVEMENT, RECOMMENDATIONS: Proactively integrate utility and private investment Coordinate piped and non-piped service provision Develop utility involvement and capacity for groundwaterresource management and protection Establish utility low-income user support units for :- construction/operation of community stand-postboreholes- advisory/registration services for private waterwellusers (with appropriate charging especially if generatingsewer discharge)

CONJUNCTIVE USE & MANAGEMENT OF RESOURCESkey to urban water-supply security

RECOMMENDATIONS (ctd)Measures to enhance the source security develop protected external municipal wellfields (withagreement between urban and rural municipalities involvedon land-use controls) establish municipal waterwell protection zones (to takeadvantage of parkland and prevent generation of pollutingdischarges) prioritise main sewerage in densely-populated zones andlimit population density of new unsewered zones undertake groundwater pollution hazard assessments andreduce dependence on vulnerable municipal waterwells

GROUNDWATER POLLUTION PROTECTION’avoiding unexpected hazards from above’ understand vadose-zone attenuation map aquifer pollution vulnerability assess pollution risk andmanage by prevent/limit measures

THANK ResearchGate.net/Stephen tions/spring

OUTLINE OF THE PRESENTATION 1) Introducing UPGro 2) Water security and ground water resources Concept of water security Role of groundwater in water security 3) Self-supply boom –current trends in use of ground water Urban growth unprecedented and growth of water demand Typical “supply” response Africa regional evolution of type of supply