APPLICATION OF SWAT MODEL IN ASSESSING THE IMPACT OF LAND USE CHANGE IN RUNOFF OF MAROON RIVER IN IRAN

Proper management of watersheds is one of the most important methods for using water and soil resources. In the last few decades, accurate and timely estimates of the quantitative and qualitative runoff status are one of the major concerns of large-scale management. The aims of this research are a simulation of monthly runoff, sensitivity analysis, optimization of sensitive parameters, investigation of the effect of land use change over the last four decades on the quantity and quality of the Maroon River (southwest of Iran) at the exit point of the Maroon Watershed (Idnak) in Iran using the SWAT model. For this purpose, the semi-distributed SWAT model and the SUFI2 program were used in the SWAT CUP software package for sensitivity analysis, calibration, validation and uncertainty analysis. In this research, the map of land use change and soil mapping and vegetation cover in the Maroon watershed were first identified over the course of the four decades between 1970 and 2010, using TM and ETM satellite measurements in Landsat. Observations of the Idnak Hydrometer Station were used as the base station during 1970 to 2010 over a period of four decades. Comparison of the effects of land use management options on various components of the hydrological cycle as well as different runoff rates show that if the pessimistic scenario occurs, and with the continuation of the destructive trend in land use to the retreat, values of runoff will increase and there will be more permeability and the drainage will go down to deeper aquifers.