A new approach to estimate cover-management factor of RUSLE and validation of RUSLE model in the watershed of Kartalkaya Dam

RUSLE is one of the most widely used soil erosion model worldwide. However, some of the input parameters of RUSLE may require extensive field and laboratory studies, and therefore in most of the cases these parameters are estimated according to some alternative approaches. In this context, cover-management factor (C) has significant importance since it is the most influential factor due to its effect on result, besides; there are some doubts about the alternative approaches which are used to estimate the C factor. Moreover, although plenty of RUSLE applications in different areas are conducted in Turkey, any comprehensive study regarding the validation of obtained RUSLE results according to specific conditions is lacking. In this study, the drainage basin of the reservoir of Kartalkaya Dam which is in the south eastern part of Turkey was chosen as the study area, and the average annual eroded material was identified though RUSLE. For the mentioned reservoir area, the availability of bathymetry measurements for 30 years time span between 1975-2005, provide the appropriate conditions to validate the results of the model since the deposited sediment volume could be quantified. Therefore, after the identification of the average annual eroded material for the sub-basins, SEDD model was applied in order to reveal the annual transported sediment amount within each sub-basin of the study area. The results obtained from the SEDD model were compared with the bathymetry measurements of the reservoir. In this context, the first objective of this study is to propose a new approach to estimate the C factor by using remote sensing and GIS techniques with previous studies based on experimental studies conducted on field. The second objective of the study is to estimate RUSLE parameters by using available datasets and to examine the applicability of the method on other basins in Turkey with same datasets. The third objective of the study is to estimate the transported sediment amount by using SEDD model, and by comparing its result with the bathymetry measurements of the reservoir to make a validation of both RUSLE and SEDD models.