This paper applies the principles of water-use accounts, developed in the first of the series, to the Ganges River basin in South Asia. The Ganges Basin covers six countries, and the river rises in the western Himalayas in Uttarakhand state, India. A unique feature is the strong seasonal variation in both precipitation and potential evaporation. The water related issues of the basin are both due to high and low flow.
Net runoff is about 37% of total precipitation. Rainfed agriculture covers 52% of the basin and uses about 32% of the precipitation. Grassland covers much of the upper part of the Basin, consuming about 9% of precipitation. Irrigated agriculture covers 25% of the Basin and uses about 18% of the water.
Changing irrigation efficiency from the currently assumes 40% to 60% and increasing the irrigated area by 10% has relatively little impact on water availability overall, since the water thus made available can be consumed downstream.
CPWF Working Paper: Basin Focal Projectseries, BFP05. Colombo, Sri Lanka: The CGIAR Challenge Program on Water and Food. 31 pp.