Determining the Main Factors Effecting the Sediment Yield from Derindere Watershed of Sir Dam in Kahramanmaras by Using GIS Techniques

Abstract

Sir Dam with 4750 ha of water reservation area is very important fresh water source for Kahramanmaras region. Sir Dam is located in Derindere watershed area where various types of soil erosions have been actively occurred. In the watershed area, the topography is very steep and the soil is very sensitive to erosion. The most of the area is not covered by erosion preventing vegetation and sufficient soil conservation precautions have not been taken during or after constructing the dam. Therefore, considerable amount of sediment yield has been transported into the dam. Besides, the dam is surrounded by near by industrial organizations and large and small size settlements, especially the city center of Kahramanmaras, which leads to a serious pollution problem in the dam due to residential and industrial wastes. The purpose of this study is to determine the effects of physiographic properties of the Derindere subwatershed, representing the features of the watersheds around the Sir Dam, on the sediment yield potential,and to suggest necessary precautions to prevent the dam filled up with sediment. The topographic properties of the watershed were determined by GIS (Geographical Information System) techniques.