Identification and Prioritization of Suitable Areas for Artificial Nutrition of Groundwater using GIS and AHP Method (Case Study: Tajan Plain)

In the coastal region reduction of groundwater is one of the most important problems. Excessive exploitation from groundwater is one of the main effective reasons that will lead to the progress of saline water, especially in seasons with low precipitation. Therefore, at the current research, identification of suitable areas for artificial groundwater recharge in the Tajan plain (with an area of approximately 33467 hectares), was conducted. For this purpose, the necessary maps including land use, geology, gradient, soil texture, dry soil thickness (non-saturated soil part) and distance from the waterway were prepared.  Then the final weight of criteria and sub-criteria were determined by using AHP method; After that, by using GIS software, the mentioned maps were combined and finally the appropriate areas were identified and prioritized. Then the different methods of artificial recharging in study area were evaluated. According to the results, 6.91, 38.80, 25.15, 21 and 8.14 percent of total studied area were completely appropriate, appropriate, normal, inappropriate and completely inappropriate for artificial recharging respectively. Because of the short distance between study area and coastal region, some options like flood spreading and construction of rubber dam is suggested to artificially recharge of groundwater and to prevent of the saline water's advance.