The impact of construction of Tangooye dam on the groundwater resources by model simulation of Sirjan plain aquifer using Modflow software

There has been a continuous over-use of groundwater resources of Sirjan plain. Due toincreasing overexploitation of groundwater, a significant decline of water levels hasoccurred. This has led to saltwater intrusion into the freshwater aquifer. Sirjan aquifersrecharge capacity has decreased as a result of construction of Tangooye Dam in 2002. Inthis study, water table variation of Sirjan aquifer was simulated with Modflow software.Parameters such as hydraulic conductivity, storage coefficient, and recharge content wereestimated with Pest subroutine. The simulation model was calibrated using observed datafor a period from 1995 to 2004. Model verification was carried out for a 12-month periodand it showed that the developed model can simulate water table variation of the aquiferand matches closely with field data with a RMSE value of 0.8923. The effective factorswere evaluated on decreasining of groundwater quality of this aquifer. Recharge volumeof this plain were computed before and after dam construction. It is concluded that thedam construction led to decreasing of recharge of Sirjan plain. The results from modelindicate that with current trend of groundwater use in this plain, groundwater storagevolume will drastically decline and there is a great danger of saltwater intrusion into theaquifer in not a distant future