برآورد ضریب رسوبدهی در حوزه آ بخیز شفارود گیلان

Generally the negative affects of any component part of a Watershed can evaluate in the intensity of its produced sediment and erosion. In any basin, the erosion amount is more than sediments, becase of eroded materials in the basin due to natural sedimentary traps. Therefore it is necessary to detemine the relationship between coefficent of sedimentation and physical parameters of any basin for planning and managing policies. The Coefficient of sedimentation-that is the ratio of sediment to erosion important for evaluating the Sedimentation of dam reservoires. So, by recognition of the effective factors in basins sediment delivery ratio, appropirate strategy of sediments control, can be proposed. Erosion and sedimentation of Shafaroud basin is very acute, because ht is one of the important sources for agricultrual Water in this area and also Shafaroud Company a large area of forest hn this area.Erosion forms hn the Shafaroud Watershed hncluded gully, stream- bank massive and landslide erosin. To determine the ration of sedimetion, Shafaroud basin Was divided to six subbasin on the basis of topography map (1:5000) and the amounts of soil erosion and sedimentation was computed using PSIAC model. And physical characteristics of basin. The relationship between the effective factors in erosion of the watershed. Results indiceted that the ralationship area of watershed and the sediment delivery ratio of the shafaroud was negative (r=-0.98). in addition the correlation of gradient has direct relationship with sediment delivery ratio (r =0.86). the relationship of concentration and the coefficent of the sedimentation was also negative (r=-0.99). the ratio of flooding had direct relationship with the cofficient of sediment delivery ratio(r=0.86). Average amoung S.D.R in shafaroud catchment was equal to 0.77 and subbasins 2/4 and 3-3 had the highest S.D.R The amounts of ersion and of sedimentation in Shafaroud basin was high. Therefor, the proper management should ecercised in cutting the wood of gungle. Becaseit is on of the main in the soil protection.