Evaluation of soil losses and sediment yield using modified PSIAC model

ABSTRACT- One of the big problems today human societies are faced with is the problem of soil erosion. In this study, the "MPSIAC model" was used to estimate sediment yield and provide sediment yield map in Cachoyeh watershed. The MPSIAC method incorporates nine environmental factors that contribute to sediment yield of the watershed. These factors are: surface geology, soil, climate, runoff, topography, ground cover, land use, channel and surface erosion. ArcGIS 10.2 software was used to prepare the map of each factor and analyze them to create the sediment yield map and erosion map. According to the results based on MPSIAC model, 94.2 % (476.1km2) of study area was classified in the slight sedimentation and 29.2 % (147.5 km2) of it was classified in the moderate erosion classes. The total sediment yield of basin was calculated as 1236.5 (m3 km−2 year−1) and the total of erosion was calculated as 5091.6 (m3 km−2 year−1). The sensitivity analysis of parameters of MPSIAC model showed that the most sensitive parameters of the model based on their importance were: channel erosion, land cover and geology with Pearson correlation of 0.75 to 0.36. Land use factor was found to have a lower effect than the output model.