Detection of unauthorised groundwater withdrawal using SWAT-MODFLOW model an‎d remote sensing

9/6/2026 12:00:00 AM

Sustainable management of groundwater resources, particularly in arid an‎d semi-arid regions, is essential for maintaining environmental balance an‎d meeting agricultural, industrial, an‎d domestic deman‎ds. Varamin Plain is one of the critical areas in Iran in terms of groundwater decline, which has been exacerbated by climate change an‎d excessive exploitation of water resources. According to evidence, the groundwater level in Varamin Plain has declined on average by 1.15 meters per year, indicating severe overextraction in the region. Therefore, identifying an‎d locating illegal groundwater withdrawals in this plain is of great importance. In this study, an integrated modeling tool combining surface water an‎d groundwater models (SWAT-MODFLOW) was applied to simulate an‎d analyze the impacts of illegal groundwater abstraction. The SWAT model was used to simulate surface hydrological processes, while MODFLOW was employed to analyze groundwater flow. To improve the simulation accuracy, Sentinel-2 satellite data were used to extract the Leaf Area Index (LAI) an‎d calibrate the model. In addition, the model was calibrated using observation well data to achieve better agreement between simulated an‎d observed values. To identify illegal withdrawals, scenarios were developed based on varying levels of groundwater pumping, assuming constant surface water extraction. These scenarios, named S1, S2, S3, an‎d S4, respectively represent recorded abstraction (baseline), increased pumping to fully meet irrigation deman‎d, reduced pumping, an‎d excessive pumping. Results indicated that among the four scenarios, S2 provided the best performance in simulating groundwater levels with the lowest simulation error. The mean RMSE values for scenarios S1, S2, S3, an‎d S4 were 2.14, 1.96, 2.07, an‎d 2.43, respectively. Model performance eva‎luation using goodness-of-fit criteria such as KGE an‎d RMSE demonstrated that the integrated model has satisfactory capability in predicting groundwater level fluctuations an‎d the Leaf Area Index. The findings of this study can assist policymakers an‎d water managers in adopting effective strategies for the sustainable management of groundwater resources.

سنجش از دور , مدل تركيبي SWAT-MODFLOW , شاخص سطح برگ , نياز آبياري , نياز آبياري

: Remote Sensing , SWAT-MODFLOW Coupled Model , Leaf Area Index (LAI) , Irrigation Water Demand , Unauthorized Groundwater Withdrawal

Fateme Hooshmand

Hosein Alizadeh