Investigation of the management scenarios for the aquifer recovery using mathematical modeling (Case study: Abarkuh aquifer)

Ground waters are considered as substantial water resources in many parts of the world especially in arid and semi-arid area such as Iran. The population growth, the intensive use ofsurface water and groundwater resources has often affected ground water levels. To meeting water management objectives it is essential to have a comprehensive study on the aquifer recharge and ground water withdrawal. In this paper 3-D analysis MODFLOW model served to simulate Abarkuh aquifer for a three year period (2013-2015) with 36 time steps. Modflow model was calibrated in two steady and Transient states. The model validation was measured using 36 month time steps (October 2009 to September 2012). Root Mean square (RMS) error was used to evaluated the accuracy of the calibrated and validated models. RMS error of the calibrated and validated models were 1.046 and 1.10, respectively.. The results showed that continuing current policies for managing water will only widen and deepen water crisis, this condition will reduce aquifer storage and result in decreasing hydraulic head by -1.5 m year-. To control this crisis different scenarios were simulated to represent the effects of ground water management on the aquifer. These scenarios including changes in irrigation methods, using of evaporation reduction methods and changes in cropping patterns. Results showed that all scenarios are capable to restore and protect the groundwater resources in Abarkuh aquifer. Therefore, adjusting crop farming structures and improving irrigation system have been important means of protecting groundwater resources in this region.