An integrated model for water resources management at basin level

A new model for the optimal multi-annual operating policy of a multipurpose reservoir is developed using an algorithm based on multidimensional dynamic programming. The water supply-inflow minus evaporation from the reservoir-is available for various uses (irrigation, environmental conservation, other). The Principle of Optimality is the maximization of the multi-annual agricultural profitability at the basin level. An exact solution of the algorithm is obtained. The optimal allocation process solves the competition for water use on different time scales (weekly, seasonal, multi-annual in subsequent dry seasons) and on different areal scales (in basins, between irrigation areas; in irrigation areas, between different crops). The solution allows the management of all the variables necessary for an accurate description of the time and areal competition levels analysed by the model without running into the so-called "curse of dimensionality" problem. The environmental use-defined parametrically-makes the solution vary according to the parameter.