The Study of Effect of Vegetation Cover Factor on the Water Erosion Case Study: Razin Basin

One of the important parameters, that reduce negative influence of the other known parameters, is cover vegetation. In this study were estimated cover vegetation influence in soil erosion of Razin basin in Kermanshah province that is our study area. The first step is preparation map of NDVI obtained & category of cover vegetation by the Landsat TM data. Then Revised Universal Soil Loss Equation with six factors (Annual Rainfall Erosivity, Soil Erodibility, Vegetation cover & Topographic) & hydro physic model with five factors (Rainfall, Topography, vegetation, area, erosion) Were used for evaluating & estimating of soil erosion in Razin basin. After product data layout of models factors to estimating of influence of cover vegetation, each models twist performance, with calculating ratio coverage & without calculating this ratio. For estimating of intensity erosion by hydro physic model, the sediment load potential calculated in surface unit. Result indicated that erosion in different land cover is variable. With the influence of other factors in the different land cover, the influence of these factors can be changed. The highest erosion have been estimated in the south, south-west & north, north-east of Razin basin. Without calculating of cover vegetation by RUSLE equation erosion amount increase from 485 metric tons per hectare per year to 650 metric tons per hectare per year, & in hydro physic model sediment load potential amount increase from 834/259 ton per km2 per year to 1900/56 ton per km2 per year.