Locating susceptible areas for short earth fill dams (Case study: Beheshtabad Watershed)

The increasing demand for water has led to the development of various methods for water resources management. Some structural methods include the construction of barriers in the path of surface flows and make water reservoirs, which earth-fill dams are in this category. Efficiency and productivity of a dam depend on many factors, most importantly, the suitable areas for the construction of these dams. This research was conducted with the aim of developing a decision support system based on RS and GIS techniques and identifying and prioritizing suitable areas for the construction of earth-fill dams in the Beheshtabad watershed of the North Karun watershed. For this purpose, previous studies in this field were reviewed and effective criteria in locating the earth fill dams were selected. After selecting the set of criteria, a pairwise comparison questionnaire was made and provided to relevant experts. Then, using the Analytic Hierarchy Process (AHP), prioritization and determination of the relative weight of these criteria were performed. Maps of each factor were prepared and standardized; then weights obtained by AHP method was then applied to them. Finally, the map was prepared with three categories of inappropriate, good, and very good for the construction of the earth-fill dam in the region. The results show that geomorphologic and geological criteria with the highest weight are the most important in determining the suitable location for earth-fill dam construction. This criterion composes of four sub-criteria: Karst, Fault, Landslide and Erosion. After this criterion, topography, investment, land use, distance from groundwater sources, distance from road and soil depth were ranked in order of importance. It was also found that more than four kilometers of the hydrological network of this watershed have a very good capability for the construction of short earth-fill dams in order to manage water resources.