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Groundwater recharge and salinization in Senegal coastal semiarid regions

Climate variability and climate change affect groundwater resources through changes in the timing and magnitude of recharge, the interaction between groundwater and surface waters, and water withdrawals. Evaluation of these impacts is essential for long-term water resource management, especially in semi-arid regions where the availability of resources is often the key to economic development. In Senegal, hypersalinity occurs upstream in tidal estuaries with salinisation of groundwater in shallow aquifers up to 200 km inland. Recent studies on several aquifers (Senegal River Delta System, North Coast Littoral, Saloum Delta and the Casamance Delta) reveal high sensitivities to climate variability and climate change. Hydrochemical evidence together with numerical and analytical models informs regional groundwater recharge and flow. Sensitivity analyses involving reductions of 10–25% in mean annual recharge reveal only minor changes in the seasonality of water-table fluctuations. In the North Coast Littoral and Saloum Delta systems, changes (–1.2 to –3 m water table lowering) are more pronounced in the high water-level zone (corresponding to the high altitude zone) where recharge mostly occurs; whereas values are negligible to nil in the lower water-level region. In the Casamance catchment and the Senegal River catchments, recharge regimes deduced from the water-table fluctuation method and isotopic signatures suggest that climate change will impact these systems, but the magnitude of these impacts will vary under different geomorphological settings

Auteur(s) : Moctar DIAW
Pages : 163-176
Année de publication : 2009
Revue : IAHS
N° de volume : Publ.334
Type : Article
Statut Editorial : Revue
Mise en ligne par : DIAW Moctar