Impact of climate and anthropogenic changes on current and future variability in flows in the Nyong River Basin (equatorial Central Africa)

Due to climate and environmental changes, sub-Saharan Africa (SSA) has experienced several drought and flood events in recent decades with serious consequences on the economy of the sub-region. In this context, the region needs to enhance its capacity in water resources management, based on both good knowledge of contemporary variations in river flows and reliable forecasts. The objective of this article was to study the evolution of current and future flows in the Nyong River Basin (NRB) in Cameroon. To achieve this, the Pettitt and modified Mann-Kendall tests were used to analyze the hydrometeorological time series in the basin. The SWAT model was used to simulate the future flows in the NRB. During the 1970s, the Nyong basin experienced a joint decrease in rainfall and flow. Despite a general decrease in future precipitation, a significant increase in runoff is expected in this basin, regardless of the period (2022-2060 or 2061-2100), the model (RCA4 or CCCma) and the scenario (representative concentration pathway (RCP) 4.5 or RCP8.5). This increase in flow will be the result of the increase in impervious areas to the detriment of forest in the basin, which will compensate for the drop in precipitation with an increase in runoff.