Stochastic multiobjective optimization model for allocating irrigation water to paddy fields

A stochastic multiobjective optimization model is presented to allocate irrigation waters to blocks of paddy fields in an agricultural district. Environmental uncertainty and temporal variation of water requirement at the fields are represented in the model formulation by employing a scenario-based description. To improve the efficiency of water use, two conflicting objectives, i.e., minimization of water withdrawal from a river and maximization of rice production, are expressed in linear objective functions. Water balances in a river, a field block and a channel network interconnecting with some blocks of paddy fields are considered as constraints. Adjusting a weight in a synthesized objective function results in producing a set of noninferior solutions, which could be useful in discussing water management alternatives in decision-making. The application of the presented model to a hypothetical irrigation district demonstrates that optimal water intake and allocations of irrigation waters could be produced.