Efficiency of the groundwater artificial recharge from dam water release in arid area

This paper describes a methodology to estimate the groundwater artificial recharge efficiency. The water table fluctuation method (WTF), stream-flow (SF) estimation method and Hydrus-1D model are used to estimate the effective water quantity reaching the aquifer. The efficiency of the stream flooding on groundwater level trend was discussed based on groundwater table fluctuation. The comparison between the three methods is found to be valuable for determining the range of plausible recharge amounts and for highlighting the uncertainty of the estimates. SF method yields the largest recharge estimate whereas the WTF method provides actual recharge reaching the aquifer. SF method and Hydrus-1D model show the best fit between estimated recharge volume and water volume released with a coefficient-of-determination (R2) of 0.9 and 0.8, respectively. The combination of the stream flow with water-table fluctuations methods is recommended to increase the constancy of recharge estimates and preliminary assessment.