This paper deals with the methodology used for conducting a water resources assessment as the core component of water resources master plans. It is basically a quantitative and qualitative water resources balance (WRB) and an essential element of any short or long-term planning of sustainable and environmentally sound river basin development and management. The use of a water resources management balance instead of the water resources balance (water budget) that includes the water withdrawals and discharges in the balance equation should be favoured in water resources assessment.
By using a water resource management balance, the multiple use of a given volume of water is accounted for so that it is possible to satisfy larger water demands than by using the natural water budget approach. This approach forces planners to look at a much wider scope of alternatives (reservoirs versus water recirculation and conservation for example) to meet the demands and also reinforces the role of water quality in water resources assessment.