Numerical simulation and prediction of regional land subsidence caused by groundwater exploitation in the southwest plain of Tehran, Iran

• Land subsidence caused by ground water exploitation in southwest plain of Tehran
• Numerical modeling and prediction of land subsidence in southwest plain of Tehran
• There is a progressive trend of land subsidence in southwest plain of Tehran, Iran.

This study characterizes land subsidence in southwest plain of Tehran using numerical modeling and predicts the trend through 2018. Excessive groundwater withdrawal has caused severe land subsidence in Tehran; in the past 28 years (1984–2012), groundwater level has decreased 11.65 m. The multi-layered aquifer system in the southwestern plain of Tehran contains three aquifers and three aquitard units. The present model was developed simulation using PMWIN (MODFLOW for Windows). First, groundwater level and land subsidence were simulated for the end of 2004. The model was calibrated using hydraulic head measurements and InSAR data. The simulation results were in fairly good agreement with the measurement results. The calibrated and evaluated model was then used to assess the future evolution of land subsidence and for prediction of subsidence through the end of 2018. Numerical results show that, assuming a constant rate of pumping in the future, land subsidence in the southwestern plain of Tehran will reach 33 cm by 2018. The study confirmed that land subsidence caused by groundwater pumping is a serious threat to southwest Tehran.