The Site Selection of Check Dams Using Fuzzy AHP Method in Urban Watersheds Ilam City Watershed

In recent decades, along with the development of the residential area, the problems of runoff and flood in urban watersheds have increased dramatically. Check dams have a direct and rapid effect on the flood. One of the most important elements of the construction of these structures is the identification of the suitable location for construction of the structure. This stage should be done with the utmost accuracy and precision due to the stability of the structure and the financial issues. In this study, the general approach is based on the fact that after identifying the area and collecting the required information, the factors influencing the construction of the structures were determined and the layers required for suitable location were prepared. After fuzzing the layers using Arc GIS 10.5 software, each layer is weighted according to the amount of its effect on site selection. Then, the layers combined using the fuzzy gamma operator and finally, after the field surveys, 22 optimal points and 3 completely optimal points for constructing the structures in the Ilam catchment area were identified. By construction of a check dams in the selected areas, it is possible to significantly reduce the damage to the facilities and waterlogging of the passageways.