The soil erosion is the most serious environmental problem in watershed areas in Iran. The main factors affecting the amount of soil erosion and sediment yield include vegetation cover, topography, soil, and climate. In order to describe the areas with high soil erosion and sediment yield risks and to develop adequate erosion preventation measures in watersheds of dams, erosion and sediment yield maps should be generated considering these factors. The purpose of this study was to investigate the spatial distribution of annual soil loss and sediment yield in Cham Gardalan watershed, Ilam Province, Iran, using Revised Universal Soil Loss Equation (RUSLE) model. Remote Sensing (RS) and Geographic Information System(GIS) technologies were used for erosion and sediment yield risk mapping, based on the this model. The R-, K-, LS-, C- and P- factors were obtained from monthly and annual rainfall data, soil map of the region, 50-meter Digital Elevation Model (DEM), Remote Sensing (RS) techniques (with use of NDVI), and GIS, respectively. The mean values of the R-, k-, LS-, C- and P- factors were 265.96 MJ mm ha−1 h−1 year−1, 0.29 t h MJ-1 mm-1, 14.31, 0.48 and 1 , respectively. The study indicated that the slope length (L) and slope steepness (S) of the RUSLE model (R2 = 0.84) were the most effective factors controlling soil erosion in the region. The average annual soil loss and sediment yield is predicted up to 38.81 and 19.01 (t h-1 year-1), respectively. The measured average annual sediment yield 16.58 (t h-1 year-1) was very close to estimated value (19.01 t h-1 year-1). Moreover, the results indicated that 47.46%, 11.22%, 9.69%, 11.29%, 20.34% of the study area was under minimal, low, moderate, high and extreme actual erosion risks, respectively. Since 31.63% of the region is under high and extreme erosion risk, adoption of suitable conservation measures seems to be inevitable. The RUSLE model integrated with RS and GIS technologies has great potential for producing accurate and inexpensive erosion and sediment yield risk maps in Iran.
کلید واژگان :GIS, RS, RUSLE, Sediment yield, Soil erosion, Cham Gardalan watershed
ارزش ریالی : 600000 ریال
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