عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Soil erosion and sediment yield from watersheds are key limitations for achieving sustainable land use and maintaining water quality in streams, lakes and other water bodies. Studying soil erosion process and sediment yield and evaluation of dominant factors on erosion is therefore considered as one of the fundamental tasks in proper management of watershed resources. Insufficient information regarding the sediment yield during storms is also one of the old issues which mainly causes failure of soil and water conservation projects. In this research, development and analyzing rating loops of Chehelgazi watershed of Gheshlagh dam were investigated. To achieve the study purposes, the rating loops of ?? storm events from winter 2006 to spring 2007 were investigated. The sediment samples were taken immediately after measuring flow velocity with half an hour interval through intergration method for 11 storm events. The sediment yield was then determined for each study storm through laboratory analysis and applying SPSS and Excel software packages. The results of the study revealed that the rating loops in all storms followed the anticlock shape. This indicated that the entire sediment graphs with duration of 88 to 273 minutes in advance with an average interval of 1.5 to 2 h preceded the hydrographs and also existence of sediment yield source in upstream parts of watershed.