Vulnerability of Water Resources to Climate Change in the Saloum River Delta, Senegal (West Africa)

West Africa is among the most vulnerable regions to climate change. This the case of the Saloum region (Senegal), characterized by a very salty ‘reverse’ estuary and limited fresh water resources for the supply of its 618,674 residents living in 23 rural districts. The main objective of this paper is to analyze the vulnerability of water resources to climate change over this region. To this end, multi model ensemble mean based on 24 bias-corrected global climate models participating in the CMIP5 has been used following the RCP4.5 and RCP8.5 scenario pathways by midcentury (2021-2050) compared to the 1976-2005 reference period, were used to estimate the potential evapotranspiration, the effective rain, the water balance and the effective water recharge. In order to characterize the sensitivity of water resources to climate change, statistical trend analyses and Geographic Information System were used to assess the following indicators: renewal water reserve, water demand dynamics and water quality evolution. The results show that for a decrease of 9% in precipitation and an increase of 1.2°c/year in temperature by 2050, renewable water reserves are likely to decrease up to 60 Mm3/year and 65 Mm3/year for RCP4.5 and RCP8.5 in Fatick respectively. In Toubacouta, the decrease in water reserves is about 136 Mm3/year under RCP4.5 and 156 Mm3/year under RCP8.5 scenario. However, water demand may increase by more than 40 Mm3 by 2050. Furthermore, the decrease in water reserves, the overexploitation of the groundwater table, the decrease of 14% in basin flows, the salinization of the land and the sea level up to 50 cm/year will affect the quality of fresh water by marine and fluvial salt intrusion by 2050.

Keywords: climate change, water resources, water demand, water quality, vulnerability, Saloum River Delta.