Determining the Factors affecting on the geometry of Gully Erosion (Case study: Darrehshahr, Ilam)

One of the types of water erosion and land degradation which causes imbalance in the area of natural resources and agricultural land and gives heavy losses, is the gully erosion phenomenon. To control this phenomenon, It is important to understand the influence factors on the geometry specification. Land degradation, a broken ecological balance of the land and landscape and risk of falling at biological resources in these areas, among other things, the study of the gully, is inevitable and necessary especially in the Darrehshahr township. In this regard, Gully 36 number were selected in Darrehshahr area in the Ilam province. To this end, were identified environmental factors, Physical - Chemical Soil properties, cover and hydrological properties of gullies tested using aerial photography, the digital maps and field operations. Results of statistical analysis using multiple regression (stepwise method) revealed that length of gully with upstream area of the gully, top and bottom width and cross section of the Gully with basin elongation, deep gully with basin elongation and slope curvature, high of head Gully with local slope of the gully and steep walls of gully with percentage cover have a significant relationship. So could be concluded that characteristics of geometry gully in the study area would be a function of the upstream, basin elongation, curvature slope, and local slope of the gully head and the percentage of canopy cover catchment area of gully.