Optimal Design of Water Diversion System: A Case Study

Study of uncertainties in the design of dam diversion is of great importance due to its high economic impact on the construction cost. It is important to study the carrying capacity of the diversion systems, considering the hydrologic uncertainties due to climate change phenomenon and its impacts in decision making. In order to consider these uncertainties, the historical rainfall data of the nearest gauge stations have been analyzed, then the rainfall variations in the future have been predicted using down-scaling of the GCM (general circulation model) data. The runoff of the basin is simulated using rainfall runoff modeling. The results of uncertainties evaluation have been incorporated in an optimization model. In this paper, a GA-based optimization model for determining the optimal sizing of a dam diversion system is developed. The proposed model minimizes the flood damages and costs based on the optimal size of the dam diversion system in a probabilistic framework. The proposed algorithm considers risk in the decision making about diversion dam height and diversion tunnel characteristics. In this model, the hydrological uncertainties and the climate change impacts in design of dam diversion system are considered in the objective function of the optimization model. The proposed methodology is applied to the Karoun-4 Dam in the south-western part of Iran. The results show the significance value of considering flood risk and climate change impact on the design of dam diversion systems.