Modeling of management measures taken to control groundwater level depletion (Hashtgerd plain- Alborz province)

Increased groundwater extraction has caused severe depletion (On average 65 cm/year) in the groundwater resources of Alborz province and especially Hashtgerd Plain in over the past few decades. Hence, considering the importance of these valuable resources, appropriate strategies should be considered for the sustainability of this resources. In order to realize these measures, the MODFLOW numerical simulation was calibrated in steady-state and transient conditions for three years (2013 to 2014) and validated for a one-year period (2015). Then, the influence of the implementation of the Iran Aquifer Restoration plan in Hashtgerd plain was evaluated and pollutant particle movement (Nitrate and Sulfate) in this scheme were investigated using MODPATH. According to the results, if the current conditions continued, the aquifer storage would decrease by an average of 1 MCM/year. Also from the management measures, the guidelines for restriction of unlicensed utilization wells and the step-by-step restriction of groundwater extraction cause improving the aquifer storage about 8.8 and 6.8 MCM/year. The results of the MODPATH also showed that if the plans such as scenarios 7 and 9 were implemented, the movement of nitrate particles (at concentrations of 30 to 70 mg/l) will be limited in the Hashtgerd city area. The study concludes, although the complete restriction of unlicensed utilization wells may work best in line with the objectives of the Aquifer Restoration Plan, the step-by-step restriction of utilization wells may be more acceptable and applicable.