Determination and modeling of suspended solids transport in the Lower Porsuk stream watershed

Soil erosion is an important problem when economic, social and environmental aspects are considered. Amount of sediment carried in suspended form with streams is known to be about 450 million tons per year in Turkey. The major sources of sediment include agricultural areas, urban areas, construction works, streambank erosion, stream bed restoration, highway construction, quarry and strip mines.In this study, the model Soil and Water Assessment Tool (SWAT) developed by the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) has been used to model runoff and sediment in the Lower Porsuk Stream Watershed in western Inner Anatolia. The study has two major parts. The first part deals with the hydrologic model and the second part identifies the effects of point and non point sediment sources. Model results indicate that on the average 25% of the annual precipitation over the watershed contributed to streamflow during the 32 year period from 1978 to 2009 and produces a sediment yield 2 ton/ha per year.