Operating rules of an irrigation purposes reservoir using multi-objectives optimization

A multi-objective optimization technique for the operation of an irrigationreservoir is presented in this paper. The study deals with two different objective functions(OF): the minimization of reservoir release deficit from the irrigation demand (OF1) and themaximization of net benefit by the demand sector (OF2). In the first step, monthlyoptimization of each individual objective was performed with a deterministic non-linearprogramming (NLP) algorithm, that gave the lower and upper bounds for the multiobjectiveanalysis. In the second step, multi-objective optimization was performed throughthe Constraint method that operates by optimising the objective function OF1, while theother (OF2) was constrained to satisfy release strategies generated by the optimization.Non-dominated set of release strategies is generated by parametrically varying the boundsof the constraints obtained from the individual optimal solutions. In the third step, theinteractive analytical Step method was applied to find the best compromise solution,between the two OFs, by minimizing the distance of each non-dominated solution to anideal solution that represents the utopian optimum for both OF1 and OF2. Furthermore, theinteractive approach allows to improve the performance of the reservoir in terms ofcompromise irrigation releases, by changing the OF values until the satisfaction ofpredetermined criteria fixed by the planners and decision makers. The proposed waterallocation model was applied to the Pozzillo reservoir operation, that supplies the CataniaPlain irrigation area (Eastern Sicily).