Zoning Watershed for Artificial Recharge of Ground Water Using AHP and GIS Techniques

Iran has a dry land with very small amount of precipitation so that its average rainfall is less than one third of average rainfall in the world. Nowadays، with increase in population demand for food increased. Therefore، utilization of water resources extended much more than the past. This amount of consumption was more than the amount of ground water resources. In other words، input source become less than output. Therefore shortage of ground water resources should be compensated through artificial recharge of ground water resources. The purpose of this study is zoning watershed for artificial recharge ground water. The analytic hierarchy process (AHP) is one of the most efficient techniques designed to multiple criteria decision making. This technique allows formulation of complex issues as hierarchy and also provides the possibility to consider various quantitative and qualitative criteria in question. To ensure the final results، potential layer of study area was provided in raster calculator، weighed overlay and weighted sum methods. The results show that among the three methods mentioned above raster calculator method allocated the maximum of area to high potential against weighed overlay that allocated the minimum area. But the weighted sum method is between the two methods and results of its confidence is higher. Among these، zones with highest potential are based on more coarse alluvial sediments and most areas with the highest density and zones with lowest potential both coincide with highest altitutes with the lowest penetration and steep slope and the low areas with high density of gypsum deposits and high rate of evaporation and temperature. The results of this study can be used in environmental management of groundwater resources and also the fruitful exploitation of optimal design of water resources and prevention of over exploitation of which can be productive.