Simultaneous optimization and simulation of multi-purpose reservoir operation rule curves under extreme hydrological conditions and complex cultivation patterns using evolutionary algorithms

Implementing appropriate operating rule curves for water resources systems and hydroclimatic conditions significantly reduce damages floods and droughts damages in the downstream area. This paper uses simulation-optimization approach to establish a multi-purpose reservoir's rule curve. The hedging method is utilized for drought, and the multi-stage flood routing method is used for floods. The melody search algorithm is employed as the optimization algorithm. The Karkhe Reservoir is a case study, facing irregular water distribution and hydrological challenges from extensive domestic and agricultural water usage, varying cultivation patterns, and flood susceptibility. The region grows two types of crops - autumn and summer crops. Autumn cultivation is fundamental and strategic, but water use for summer or water-based crops reduces water resources for it. Meeting water demands from September to November is another challenge due to the overlapping water needs of summer and autumn crops. Significant changes in the upstream and downstream areas, including alterations in the shape and water resource utilization of the catchment area, as well as changes in the rivers' morphological condition and water carrying capacity, make it a constant challenge to determine the optimal water level for the reservoir. The results demonstrate the satisfactory performance of the optimized rule curve.