Modeling saline water intrusion and determining the interphase boundary in the desert aquifer of Sarayan plain

Document Type : Research paper

Authors

1 Department of Water Engineering, Faculty of Agricultural Technology, University of Tehran, Iran

2 Water Research Institute, Ministry of Energy, Tehran, Iran

10.22034/hydro.2024.61289.1314

Abstract

The advancement of saline water intrusion into freshwater tables is not limited to islands and ocean coasts, but it can also render aquifers unusable through the intrusion of saline water from deserts, marshes, and saline pits. This study examines the quantitative and qualitative impact of saline water intrusion from deserts on the Sarayan Plain, presenting managerial scenarios, simulations, and predictions. To simulate the quantitative status of aquifers, the MODFLOW model was utilized. Subsequently, the MT3DMS package was used to model the quality of saline water intrusion, and the SEAWAT model was employed to simulate and predict the intrusion fronts of saline water. The results indicate that the maximum intrusion of saline water occurs up to 750 meters along the aquifer in the southeast region of the Sarayan aquifer, with an average salt concentration increase of 160 milligrams per liter in extraction wells. The exploitation scenarios show that a 5% reduction in pumping from extraction wells leads to a decrease in the intrusion fronts by 700 meters, a reduction in the advancement of saline water in the plain aquifer by 1200 meters, and an increase in salt concentration by 464 milligrams per liter, which is 10% less compared to the current trend assumption. On the other hand, reducing the extraction from exploitation wells by 15%, leads to a decrease in the water table level, as well as an average salt concentration reduction of 82 milligrams per liter.

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