Estimation of Stormwise Sediment Yield of Gully Erosion Using Important Rainfall Components in Different Land Uses of Zagros Forest, Iran

Erosion is one of the important social-economic problems in Iraniancatchments that have been posed by surface water vastness and runoff production. So, thestudy of water resources, soil erosion and effective factors is of high importance. Gullyerosion also extends in many parts of Iran and its study particularly in viewpoint ofsediment yield is therefore very important and should be taken into account. In order toinvestigate the relationships between sediment yield of gully erosion and rainfallparameters such as amount, intensity and duration of them, the present study wasconducted in Alashtar, Lorestan province, Iran. For this purpose, 18 digitalized linear andfrontal gullies have been identified and morphological characteristics of the gullies werespecified at the beginning and after five Storm Runoff productions in November 2007 toMay 2008. Then, using matrix correlation and regression analysis, the most effective factorin the sedimentation of Gully erosion was determined. The results have showed that themost important climatic factors that can be pointed out with respect to the sedimentation ofgullies were the maximum and average rainfall intensities. Results of regression analysishave also indicated that the maximum intensity of rainfall is the most important factor inthe study area and has the ability to estimate sediment and erosion rates caused by thestorms with the coefficient of determination as (R2=0.91) and the standard error value of18.8.