As a major source of energy, the proper utilization of hydro sources are an important task. For economic operation of a power system where the hydro plants constitute a significant portion of the installed capacity the efficient utilization of hydro resources plays an important role. The optimum scheduling of hydrothermal plants is one of the important planning task in power system operation. The generation scheduling problem consists of determining the optimal operation strategy for the next scheduling period, subjected to a variety of constraints. Determination of daily optimal hydroelectric generation scheduling is a crucial task in water resource management. By utilizing the limited water resource, the purpose of hydroelectric generation scheduling is to find out the magnitude of water releases from each reservoir and hydro plant so that the total benefit of hydro generated energy can be maximized, while the various physical and operational constraints are satisfied.