Effect of Land Use Change on Runoff yield Using WetSpa Model in the Firoozkooh Watershed Basin

The main objective of this research is investigating the effects of land use change on hydrological conditions in the Firoozkouh Watershed. Land use maps for the years 2000 and 2014 were prepared through a synthetic method using the Landsat 5 and 7 satellite imagery. Runoff simulation was carried out on a daily basis for 8 years (5 years for calibration and 3 years for validation) using the WetSpa model for land use in 2000 and 2014. Land use change showed that conversion of rangeland to farm fields and residential areas is the main change of land utilization in the Firoozkooh Watershed. Results showed that total runoff, surface runoff and peak discharge had increased following land use changes from 2000 to 2014. The total runoff in 2000 was 1480.22 m3h-1, and for the year 2014 it was 15350 m3h-1. Results showed that parts of the rangeland in the Firoozkooh Watershed, which had been converted to farmfields become agricultural and residential area during the past years had increased changed the runoff volume as well as peak discharge