در برآورد رسوبدهي حوزه آبخيز دركه در شمال تهران MUSLE و MPSIAC مقايسه و ارزيابي دو مدل

Evaluation of MUSLE and MPSIAC Models for Sediment Yield Prediction in Darakeh Watershed in Northern Tehran

For preparing the maps, Cosmos satellite colored picture with a scale of 1:25000 was used. For determining the areas, distance as well as overlying the maps GIS (Geographical Information System), and ILWIS software (Integrated Land and Water information System) were used. To advise better and more effective sediment prediction models, this study on Darakeh watershed, northern Tehran, was carried out. Darakeh watershed is of many significant aspects in location and characteristics, therefore though MUSLE and MPSIAC models sediment yield in this watershed was determined. MUSLE was used as a model, which predicts events and annual sediment yields in watersheds. It was found that coefficient of 11.8 and exponent of 0.56 are not suitable for this watershed. Therefore, with use of observed sediment yields of events, coefficient and exponent were corrected to 0.234 and 0.53 respectively. New coefficient and exponent were used to calculate sediment yield with the results showing a close correlation (r2=0.96) with the observed data of events. The predicted annual sediment yield also shows 17.6 percent difference with observed sediment yield. MPSIAC model was used to predict annual sediment yield by correcting land use factor. However, predicted sediment yield was found to be 157 percent more than the observed annual sediment yield. In this study twenty years of rain data and discharge, as well as 12 years of sediment yield data were used for statistical analyses.