Site selection of water storage based on multi-criteria decision analysis

Water loss can be minimized and conserve through constructing small storage dams for various irrigation purposes to support local livelihood. Geographic information system provides powerful techniques for many hydrological modeling and suitable dam site selection. The current study explored potential sites for small storage dams to meet agricultural requirements in district Malakand, Khyber Pukhtunkhwa. Multi criteria decision analysis was used for selection of suitable sites for storage dam for agricultural purpose. The methodology was completed in four main steps; acquisition of data, selection of factors and constraints, giving percentage influence to each criterion and performing weighted overlay. Digital elevation model was used for watershed analysis and Landsat 8 image for land use classification. All contributing factors such as slope, soil map, settlements, canals, roads, river, watershed and recreational sites were used in weighted overlay for suitable site selection. Results showed that Masooka rockland soil possessed the highest suitability for dam construction as the high clay proportion of the soil provides cementation. Slope zone of 0-3.16 degree slope was considered best and 3.16-7.90 degrees was highly suitable. Distance (5-10 km or more) form recreational sites and presence of 140-186 Stream links which makes the site more suitable. Regarding land use, the barren land or rangeland was more preferable. Finally, 15 sites were found suitable for small storage dams in the district. The main river lies close to the selected site assuring the perennial flow of water. The study suggests that geographic information system provides efficient tools for decision makers in hydrology and dam site selection.