An Approach to Estimate the Efficiency of Artificial Recharge System in Ephemeral Rivers and Optimization of Major Dimensions of the System (Case Study: Emamzadeabdollah River)

Considering the overuse of the aquifers and flow regime of ephemeral rivers of the country، performing artificial recharge projects in these rivers is necessary. Although، there have been a considerable number of researches in the artificial recharge system، there has been no method for determining the recharge efficiency of the artificial recharge systems on ephemeral rivers yet. The goal of this research is to determinethe recharge efficiency of the artificial recharge systems by using the flood flows of ephemeral rivers. In the suggested method، the first step is dividing the flood hydrographs of different return periods using model between different parts of the system. So the intake efficiency of ponds is determined. Then، accordingto the dimensions of recharge ponds and the penetrated water during the flood، the amount of water that can be recharged may be determined using seepage formula. For determining the river bed infiltration، a combination of hydraulic modeling using Hec-Ras simulation and Etcheveri method has been used. Finally، after determining the recharge efficiency of system for different return periods of flood، the total recharge efficiency of the system is determined by calculating the expected value. The suggested methodis applied for the artificial recharge system of Emamzade Abdollah River of Semnan، in center of Iran. The results show that the presented method has a suitable recharge efficiency and is able to use %81 flood flow for artificial recharge