Sediment Yield Investigation using Hydrophysical Model and GIS in Forest Watersheds

ABSTRACT: One of the most important models for investigating sediment yield in forest watersheds is the hydrophysical model. In order to estimate the sediment yield potential in this study, the watershed was divided into seven subbasins using topographic maps. Then, hydrophysical factors including area, slope, erosion potential, vegetation and rainfall were analyzed. After the evaluation and calculation of hydrophysical factors and their impact on erosion, sedimentation coefficient and rate were calculated using the model. In order to make possible the comparison between subbasins, the sediment yield potential of each subbasin was divided by its surface area in hectare; and therefore, the amount of ‘sediment per hectare’ was obtained. The results showed that Javaherdeh Subbasin, is the first priority; in Nildasht and Lat-Mahalleh Subbasins were obtained the lowest amounts. Also, it is possible to calculate the sediment yield potential for the subbasins of a watershed based on priority using the hydrophysical model, which makes it a suitable model for soil conservation and watershed management projects.