This chapter presents a combination of goal programming and mixed-integer programming models formulation for a reservoir system. Only gauged flow parameter is taken to determine optimum reservoir storage at any given time and the least downstream flow to minimize the flood water flow in the downstream section of the reservoir. To determine the optimal reservoir release at a particular time flow, the downstream and storage of the reservoir are considered as objective functions in accordance with their priority where downstream flow is given the highest priority or weight. In this chapter, we have executed various hypothetical hydrographs considering two models determining the stability and efficiency of a certain reservoir to minimize flood damage.