Projected Hydroclimate Changes over Senegal (West Africa)

Understanding and assessing hydroclimate changes is essential to provide reliable information in developing countries such as Senegal in order to guide adaptation strategies. In this work, we have examined the projected changes in temperature and precipitation over the six eco-geographical zones in Senegal. Furthermore, we have assessed the river flow changes in the three major river basins (Casamance, Gambia, Senegal). Climate simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) were analyzed. The ensemble mean of the climate models projects a continued increase in mean, minimum and maximum temperatures across Senegal (up to more than 4 ℃ in the long term under the SSP5-8.5 scenario). The projected warming is greater in eastern Senegal and the Sylvo-pastoral zone. As for rainfall, it is characterized by very high interannual variability; the projections show decreasing trend from 2015 to 2100. The groundnut basin is the most area affected by the decrease in rainfall (24%). However, slight humidity conditions are projected for the near future (2021–2040). The downward trend of rainfall is much more pronounced around 2045 to 2100. In addition, we found a slight increase in extreme wet events that are more marked in the near future. This could increase the risk of flooding in urban and peri-urban areas. Moreover, future flows are strongly impacted by climate change. Thus, the stations of Kolda (Casamance River), Gouloumbou (Gambia River) and Kidira (Senegal River) could experience a slight increase in flow rates (up to 20%) by 2030; while by 2060 and 2100, a decline of about 40% is projected. Our findings can help the water managers and decision-makers to better plan their adaptation measures.