Assessment of land suitability impacts on runoff values using SWAT ‎model (Case study: Karde watershed)‎

One of the suitable strategies for runoff management in watershed area is correct use of land according to its ‎capability. Watershed manager could be offer optimal land use between different combination of land uses ‎according capability and limitations which existing in watershed. The purpose of this study is land suitability ‎classification using Fuzzy-AHP method in the Kardeh dam watershed of Mashhad and its effects on runoff ‎quantity using SWAT model.‎‏ ‏For this purpose, the present land use map of the study area was prepared using ‎remote sensing and field surveys. The SWAT model was calibrated and evaluated using current land use map. ‎Then, criteria and constraints were determined for rangeland, agriculture, forest, and urban land use. Land ‎suitability map for mentioned land uses was prepared using combination of Fuzzy and AHP method by MCE ‎in EDRISI software. The prepared land suitability map introduced into the SWAT model instead to the existing ‎land use map and results were evaluated. Results showed that 13.98 percent of the watershed area is suitable ‎for forest and the area of rangelands has decreased in land suitability map. The results of the SWAT model ‎showed with optimal land use in Karde dam watershed, mean and maximum of daily discharge have been ‎reduced respectively 16.25 and 4 percentages. Reduction of the discharge amount helps to flood declining and ‎recharge of groundwater.‎