Population growth, urban expansion, and the development of agricultural and industrial sectors have significantly increased the demand for freshwater. Due to climate change and the rising need for water, the exploitation of groundwater resources—particularly in arid regions—has sharply intensified, leading to a decline in water table levels and reduced groundwater reserves.

The aim of this study is to evaluate the quantitative effects of water demand management programs—including improving irrigation efficiency and changing cropping patterns—on the Dehgolan aquifer, the largest aquifer in Kurdistan Province. For this purpose, three-dimensional groundwater flow modeling was performed using the MODFLOW model, while surface water modeling was conducted using the WEAP model. Demand and supply values were then estimated for various sectors including rural and urban domestic use, industry, agriculture, and environmental needs. Finally, the monthly fluctuations in the groundwater table during the prediction period were assessed under three scenarios: baseline, improved irrigation efficiency, and changes in cropping patterns, by integrating the WEAP and MODFLOW models.The results from the coupled WEAP-MODFLOW model showed that the average annual change in the storage volume of the Sang-e-Siah Dam reservoir during the prediction period under the baseline, improved irrigation efficiency, and cropping pattern change scenarios were -20.02, -10.68, and -11.73 million cubic meters, respectively. Under the combined management scenario (improving irrigation efficiency and altering cropping patterns), the average annual recharge to the aquifer is estimated to increase by 17.63 million cubic meters. Although implementing this combined management scenario will not fully eliminate the negative groundwater balance of the studied aquifer, it will bring the water table level at the end of the prediction period closer to that at the beginning of the period. Therefore, this management approach has the potential to contribute significantly to the aquifer’s recovery.