The estimation of erosion and sediment by using the RUSLE model and RS and GIS techniques (Case study: Arid and semi-arid regions of Doviraj, Ilam province)

Nowadays, soil erosion is expressed as one of the important topics of watershed management at national and international level. The estimation of soil reduction risk and its spatial distribution is one of the important factors for the successful assessment of soil erosion. , The purpose of this study is prediction of annual loss potential of soil and sediment load. The soil reduction due to erosion can be obtained by using prediction model like the Universal Modified Equation of Soil Erosion (RUSLE). In this research, the RUSLE model is used for estimation the erosion and sediment yield in Doviraj watershed located in Ilam province, Iran. The RUSLE factors are included R, K, LS, C and P that are calculated from data of rainfall, region soil map, Digital Elevation Model (DEM) and remote sensing techniques, respectively. The mean values of R, K, LS, C and P factors were equal to 209.04 MJ mm ha-1h-1y-1, 0.51 Mg ha h ha-1MJ-1mm-1, 10.16, 0.53 and 1, respectively. The mean annual sediment yield was calculated as 273.6 ton/hectare/year in the study area that was close to the measured value from Doviraj sediment gauging station (253.42 ton/hectare/year). The calculated sediment value is 7.96% more than that of the measured sediment value (observed) (based on calculating the relative error). Therefore, there is no significant difference between rate of the observed and calculated sediment. Also the results showed that measurement of remote sensing techniques and GIS can be used for evaluate and calculate the rate of erosion and sedimentation.

soil erosion, RUSLE model, remote sensing, GIS, Ilam province.