Numerical modeling of unconfined aquifer artificial recharge plan using Isogeometric analysis method

Currently, uncontrolled extraction of groundwater resources has led to a decline in the water table of aquifers, especially in arid and semi-arid regions. Today, one of the ways to improve the water table of aquifers is the use of artificial recharge plans. This study has been done to numerically simulate the artificial recharge plan of Birjand plain through the construction of injection wells using the numerical model of Isogeometric analysis. In this regard, first a standard example with two wells with discharges of 1142.85 and 1428.57 m3/day was used to simulate the water table for 210 days. After evaluating the accuracy of the model, the water table before injection was simulated based on the existing conditions and after injection using 20 injection wells with a constant flow of 7638.44 m3/day in 12 time steps in the unconfined aquifer of Birjand plain. Comparison of the results of Isogeometric analysis and analytical solution model in standard aquifer with estimated evaluation criteria equal to ME=-0.0096, MAE=0.0111 and RMSE=0.0146 and also in Birjand plain unconfined aquifer with evaluation criteria of ME=-0.033, MAE=0.372 and RMSE=0.229 shows the model accuracy in simulating the water table before injection. Also, after running the numerical code of the injection wells construction plan, by interpolating the water table obtained at the control points in the location of 10 existing observation wells, the results at the end of the simulation period shows increasing the water table maximum 60.53 cm in observation well number 2 and minimum 1.25 cm in observation well number 9.