Estimating groundwater recharge from water isotope (δ2H, δ18) depth profiles in the Densu River basin, Ghana [Estimation de la recharge des eaux souterraines à partir des profils en profondeur des isotopes de l'eau (d2H, d18O) dans le bassin de la Rivière Densu, Ghana]

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dc.contributor.authorAdomako, D.
dc.contributor.authorMaloszewski, P.
dc.contributor.authorStumpp, C.
dc.contributor.authorOsae, S.
dc.contributor.authorAkiti, T.T.
dc.date.accessioned2019-04-30T10:26:20Z
dc.date.available2019-04-30T10:26:20Z
dc.date.issued2010
dc.description.abstractAccurate estimation of groundwater recharge is essential for the proper management of aquifers. A study of water isotope (δ2H, δ18O) depth profiles was carried out to estimate groundwater recharge in the Densu River basin in Ghana, at three chosen observation sites that differ in their altitude, geology, climate and vegetation. Water isotopes and water contents were analysed with depth to determine water flow in the unsaturated zone. The measured data showed isotope enrichment in the pore water near the soil surface due to evaporation. Seasonal variations in the isotope signal of the pore water were also observed to a depth of 2.75 m. Below that depth, the seasonal variation of the isotope signal was attenuated due to diffusion/dispersion and low water flow velocities. Groundwater recharge rates were determined by numerical modelling of the unsaturated water flow and water isotope transport. Different groundwater recharge rates were computed at the three observation sites and were found to vary between 94 and 182 mm/year (± max. 7%). Further, the approximate peak-shift method was applied to give information about groundwater recharge rates. Although this simple method neglects variations in flow conditions and only considers advective transport, it yielded mean ground water recharge rates of 110-250 mm/year (± max. 30%), which were in the same order of magnitude as computed numerical modelling values. Integrating these site-specific groundwater recharge rates to the whole catchment indicates that more water is potentially renewed than consumed nowadays. With increases in population and irrigation, more clean water is required, and knowledge about groundwater recharge rates essential for improving the groundwater management in the Densu River basin can be easily obtained by measuring water isotope depth profiles and applying a simple peak-shift approach. © 2010 IAHS Press.en_US
dc.identifier.other10.1080/02626667.2010.527847
dc.identifier.urihttp://ugspace.ug.edu.gh/handle/123456789/29681
dc.language.isoenen_US
dc.publisherHydrological Sciences Journalen_US
dc.subjectDensu River basinen_US
dc.subjectGhanaen_US
dc.subjectGroundwater rechargeen_US
dc.subjectUnsaturated zoneen_US
dc.subjectWater isotopesen_US
dc.titleEstimating groundwater recharge from water isotope (δ2H, δ18) depth profiles in the Densu River basin, Ghana [Estimation de la recharge des eaux souterraines à partir des profils en profondeur des isotopes de l'eau (d2H, d18O) dans le bassin de la Rivière Densu, Ghana]en_US
dc.typeArticleen_US

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