Hydrological simulation scenarios for predicting the future water status of the Niger River in Bamako, Mali, for sustainable development.

The Niger River is critical in providing water for the socio-economic activities and development of Bamako city. However, predicting future water supply and demand is challenging. Therefore, an approach capable of analysing water availability is necessary. This study aims to use the Water Evaluation And Planning (WEAP) software to forecast water availability, treatment scenarios, and the reuse of treated wastewater by 2030. Evaluating the future pollution of the river in Bamako, the simulated flow, Dissolved Oxygen (DO), and Biochemical Oxygen Demand (BOD) along the Niger River from 2017 to 2030 were compared with 2016 values. Notwithstanding the elevated water demand resulting from the accelerated urbanisation and industrialisation, the entire length of the Niger River in Bamako would be contaminated. Even though the water tends to improve downstream, a BOD concentration of 9.83 mg/l will exceed the requirement of 5 mg/l set by the European Commission's recommendation for surface water quality. The high BOD downstream indicates the river's weakening capacity for self-purification and points to a 0% water demand coverage by 2030. Contrary to irrigation needs, the river cannot be used for domestic purposes due to pollution. Establishing wastewater treatment systems will improve the reuse of treated wastewater and reduce pollution levels in the Niger River by 86%.