Effect of Improvement in Surface Water Delivery and Distribution Processes on Reduction of Groundwater Overexploitation in Rudasht Irrigation Network

 This study investigated the impact of improving surface water delivery and distribution systems on reducing groundwater abstraction. For this purpose, the current operational management of the Rudasht irrigation network, located in Isfahan province, was modeled and evaluated. Then, impact of two methods as the modernization alternatives, including an improved manual operation and an automatic control system by using the Model Predictive Control (MPC), was investigated. Operation of the canal system was simulated under two operating scenarios, demonstrating the operational status under the normal and water shortages conditions. Improvement of water supply and distribution process in the canal was evaluated using adequacy and dependability indicators of water distribution. In the next step, the amount of surface water replaced by groundwater was calculated by improving the process of water distribution in the main canal based on spatial analysis of the adequacy index. The results obtained from the operational simulation in the normal condition scenario showed improvement of the adequacy index by 5% and 32% and the dependability index by 7% and 21%, respectively, for the improved manual method and MPC. Moreover, the improvement in this scenario resulted in 3% and 25% reduction in the aquifer extraction, respectively, for the modernization alternatives. Operational simulation results under the water shortage scenario revealed 2% and 13% higher adequacy index, and 11% and 25% improvement in the dependability index by employing the improved manual and MPC approaches, respectively. This improvement resulted in 1% effectiveness for the improved manual method and 9% effectiveness for the MPC method in reducing aquifer abstraction under water shortage scenario. According to the spatial maps of the adequacy index obtained for the MPC method, this method can achieve more uniform and fair water delivery to farmers, especially under water shortage conditions.