Assessment of climate change impacts on streamflow in the Inner Niger Delta under CMIP6 scenarios

ABSTRACT The Inner Niger Delta (IND) is an important water source for agricultural water supply, fish production, and livestock breeding. It sustains the livelihoods of more than 3 million people and is a driver of the rural economy of Mali. However, the growing water demand and the anticipated effects of climate change cast some uncertainties on the future of the resources in the basin. In this research, the effects of projected climate change on the water resource in terms of streamflow were investigated using the semi-distributed catchment model Niger-HYPE. The model was first calibrated, validated, and then forced with future rainfall, temperature, and potential evapotranspiration (PET) to simulate the future streamflow for 2021–2050 under two Shared Socioeconomic Pathways (SSPs), namely SSP126 and SSP370. Results indicated a warmer and wetter climate in the basin with an increase in the mean annual rainfall, temperature, and PET on average by 6.5%, 1.25 °C, and 5.3%, respectively. The annual streamflow increased by 7% and 10% for SSP126 and SSP370, respectively. These results have many implications for water resource management in the basin. Adaptation and mitigation strategies are necessary to counter the negative impacts of an anticipated drier dry season.