Site Selection of Groundwater Artificial Recharge by Flood Spreading Method (Case study: Qalhar of Delijan)

Determining suitable areas for flood spreading is essential for the artificial recharge of groundwater. Qalhar of Delijan plain has decreased by more than eleven meters in groundwater level during the last 10 years and needs to balance the aquifer. In this research, a hierarchical analysis process (AHP) and geographic information system (GIS) were used to select site for the flood spreading in the Qalhar of Delijan Basin (Markazi Province). The study was conducted in three stages. In the first stage, the most important criteria and effective indicators to select site for artificial recharge were determined. In the second stage, a hierarchical method was used to assess and prioritize these criteria. For this purpose, criteria for flood characteristics, slope, permeability, geology, storage factor, land use were used. The results showed that flood and gradient criteria are more important in determining suitable areas for groundwater artificial recharge in the Qalhar basin. In this regard, the storage coefficient and land use have less relative weight. In the third step, based on the weights matrix, the Rasterian information layers were combined with AHP extension in Arc GIS and flood spreading Spatial preference map was prepared. The results showed that considering the restricted areas and the areas susceptible to artificial recharge, 29.3% of the total catchment area is suitable for flood spreading, which covers an area of 4250 hectares.