Simulation and Optimization of Dam Operation under Changing Cultivation Pattern Scenario (Case Study: Harsin Dam)

Due to population growth, shortage and severe constraints of water resources in the country, one of the main steps in management and planning of water resources is to optimize reservoirs and change the cultivation pattern. In this study, using 40 years discharge data of Kamish River and WEAP model, Hersin dam reservoir which is uder study, was simulated. Firstly, by considering different cultivated patterns, the reliability of domestic, industrial, agricultural, and environmental requirements were simulated by WEAP model and the proper crop pattern was selected on the basis of greater sustainability of the system. Then, optimization was performed by minimizing the shortages in downstream of the dam using LINGO model. According to the results, the annual average demands of environment, drip-irrigated gardens, sprinkler-irrigated lands and wastewater waterline, were estimated to be 98.98, 87.51, 89.79, and 95.63%, respectively, while these values obtained from the optimization model were 100, 99.99, 99.21, and 99.12%, respectively, which indicates that the percentage of shortcomings is less than 1%. The average overflow volume in simulation and optimization models were 7.31 and 4.09 million m3/year, respectively, which indicates that the optimization model has a lower water lost than the simulation model. Hence, by appropriate planning and management, it is possible to deduct the amount of deficits significantly, especially in the sector of agriculture.