Water Supply Planning Model for West Africa

Abstract

A model is formulated for use in the arid, underdeveloped Sahel-Sudan region, West Africa. Its purpose is to determine either the least cost set of sources to meet fixed demands or the sources and water uses that maximize the net benefits of water use. Since for planning purposes the model is designed to apply to the entire region and some subareas have only small-scale development options, both large and small-scale development of a wide variety of demands and supplies are modelled. The model is a mixed integer programming (MIP) optimization model. The objective function can be expressed either as the minimization of supply costs or as the maximization of the net benefits of water use. The major constraints are that in each planning subarea and in each season hydrologic continuity must exist, and demand must be met. The major decision variables are the capacities of supply sources, and in the net benefit maximization case, the water demand quantities. MIP is used to model the possibility of different reservoir operating at a site.