Early Release Reservoir Operation Simulation Model of Multi Reservoir

This research intends to investigate the effectiveness of reservoir operation pattern for flood control in the parallel reservoirs of Tugu and Bagong reservoirs. These parallel reservoirs meet in the same junction before the town house of Trenggalek Regency. The Tugu reservoir supplies water requirement in 1,250 ha irrigation area, 12 l/s raw water supply, and 0.40 MW mini hydro electrical power. However, Bagong reservoir supplies water requirement in 857 ha irrigation area and 465 l/s raw water supply. The beneficiary from the two reservoirs do not overlap with each other except as the function of flood control. The methodology consists of simulation of reservoir operation based on the irrigation and raw water supplies, simulation of reservoir operation for flood control, and assessment of reservoir reliability. The reservoir operation pattern for flood control focuses on the decreasing of reservoir water level during the flood period so there is an empty space that can be utilized as flood control storage by regulating the outflow structure because the spillway structures of both reservoirs are not completed by regulator gates. The research result is hoped can obtain the most optimum flood storage by considering the maximum capacity in the river downstream of each reservoirs so it can minimize the flood risk due to 25 years return period.