Cost effectiveness of sediment management strategies for mitigation of sedimentation at Jebba Hydropower reservoir, Nigeria

Abstract

Inthisstudy,acalibratedhydrologicmodel,SoilandWaterAssessmentTool (SWAT) interfacedwithGeographicalInformationSystem(GIS)toolwasusedtostudytheeffectofdiffer entsedimentmanagementmethodsinawatershed(12,992km2)upstreamofJebbaLake,Nigeria. Sedimentmanagementstrategiesconsideredare(i)reforestationofthewatershed,(ii)applicationof vegetativefilterstrip(VFS)and(iii)constructionofstonebunds.Costanalysisofimplementingthe selectederosioncontrolmeasureswithinthewatershedwasalsocarriedout tocomparethecost effectivenessof eachof themanagement strategies.Theresults showedthatapplicationofVFS, reforestation, andstonebunds tocritical zonesof thewatershedreducedthe sediment yieldup to65.6%,63.4%and12%respectivelywhilethefinancialanalysisof implementingreforestation, VFSandstonebundsrevealed84.9%,73.3%and70.5%reductionrespectivelyinthecoststobe incurredifsedimentsareallowedtoaccumulateinthedam.Fromthisanalysis, itcanbeconcluded thatthesedimentmanagementscenariosconsideredinthisstudyarecosteffectiveandsustainable whencomparedwiththecostsincurredintacklingtheeffectduetoreservoirsedimentation.Over all, thestudyshowedthathydrologicalmodelssuchasSWATcanbeusedtostudystrategiesfor waterresourcemanagement. Inaddition, itcanprovidepolicymakersthedecisionsupport tools toevaluatethecostandbenefitsofadoptingBestManagementPractices(BMPs)particularlyfor sedimentcontrol inerosionpronewatersheds.