Dynamic fuzzy criterion model for reservoir operations and a case study

Reservoir operation is a special inventory problem under conditions of uncertain supply and controlled demand. In this paper, we will restrict our attention to reservoir operations. In many cases, the problem which the reservoir manager is concerned with is not to maximize the direct economic benefit, but to operate the reservoir system as normally as possible, i.e., to fulfill the requirement for water demand, recreation, fishing, generating electricity, and ecology, etc., and to avoid flooding, as much as possible. This paper presents a dynamic fuzzy criterion model (DFCM) for reservoir operations. In DFCM, a satisfactory degree function is adopted as a criterion function. The objective is to let the reservoir system be in the highest possible satisfactory state. This model is available to the reservoir system whose parameters are fuzzy or whose economical benefits are very difficult to measure. We obtain the existence, uniqueness, and stability theorems to the equation of DFCM, and prove that the optimal release policy for a reservoir is a bounded critical number policy. Finally, the application of DFCM in Qinhuangdao region water resource system is discussed.