Land use planning based on SWAT model in a mountainous watershed to reduce runoff and sediment load

Soil erosion is a major environmental threat to the sustainability and productive capacity of soils. This study aimed to identify optimal land use types for Zayandehrood watershed in central Iran for the first time which is large and mountainous to minimize runoff production and soil loss. Two different types of land use data for two scenarios were developed using Soil and Water Assessment Tool (SWAT) in combination with Sequential Uncertainty Fitting Program (SUFI-2) at the sub-basin level with uncertainty analysis to explicitly quantify hydrological components on a daily time step. In the first Scenario, the current land use map of the study area was used and the second Scenario was constructed using an optimal land use map obtained from a land evaluation study. Promotion of the land uses in the second scenario resulted in a noticeable reduction in discharge and sediment productions in the watershed. The simulated mean discharge values by the Scenarios 1 and 2 were about 14,658 and 13,290 m3/year, respectively. The mean annual sediment yield simulated by the Scenario 1 (about 122,220 ton/year) decreased to that of the Scenario 2 (94,440 ton/year). This study provides a strong basis for reducing runoff and sediment yields in central Iran; however, its general analytical framework could be applied to other parts of the world that are facing similar challenges.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author