Predicting water level drawdown and assessment of land subsidence in Damaneh-Daran Aquifer by combining numerical and analytical models

Subsidence is affectedby several factors, the most important and most common of which is excessive groundwater extraction from alluvial aquifers and, conversely, reduced aquifer recharging.Subsidence of the Damaneh-Daran plain, like many of the country's plains has recently expanded.The alluvial aquifer of the plain is unconfined, but part of it operates confined due to lithological diversity and has the potential for subsidence.In this regard, in this paper,first the subsidence rate inthe aquifer was determined by radar interferometer method and the results showed that the subsidence is almost spread in most of the southeastern part of the plain and its maximum is about 6.38 cm.In order to correlate the drop in water level in the aquifer with land subsidence, the aquifer model was prepared by finite difference method, which indicates an alluvial aquifer tank deficit of 33.8 million cubic meters. Prediction of groundwater level due to50% reduction of pumpingfrom the aquifer compared to current pumps showed thatthe predicted water level shows a correlation of more than70% in thesoutheastern part of the aquiferwhere similar conditions of the aquifer are confined with subsidence and indicates its significant effect on reducing subsidence in the aquifer.The results of this study show that oneof the most important proposed solutions to control the current state is to reduce the exploitation of groundwaterresources at least 50%, which can be important bymodifying the licenses of wellsand then closely monitoring the allowable abstraction. It can be done through the installation of smart meters and the optimaluse of water inthe agricultural sector.