This paper applies the principles of water-use accounts, developed in the first of the series, to the Niger River basin in West Africa. The Niger Basin covers 10 countries, and rises in the highlands of southern Guinea near the border with Sierra Leone just 240 km inland from the Atlantic Ocean, but there are substantial downstream tributaries from Cameroon and Nigeria. A unique feature is the inland delta which forms where its gradient suddenly decreases.
Net runoff is about 12% of total precipitation. Grassland is the most extensive vegetation, covering 50% of the Basin, consuming about 39% of the precipitation. Rainfed agriculture covers 26% of the basin and use about 27% of the precipitation. Irrigated agriculture covers less than 1% of the Basin and uses also less than 1% of the water.
Climate change, using an assumed change in rainfall distribution, shows that climate change may have a large impact on water availability in the lower Basin, and hence on the River’s wetlands.
CPWF Working Paper: Basin Focal Projectseries, BFP09. Colombo, Sri Lanka: The CGIAR Challenge Program on Water and Food. 26 pp.