بررسی نقش شیب در رسوبزائی آبکندهای استان لرستان

Water erosion sculpts the Earth's surface in various ways, with gullies representing a particularly advanced form. Defined by steep sides and an actively eroding head, they develop due to episodic flow events. Climate, slope, land use, and geology are considered the primary factors influencing gully development. This study examines the role of slope in gully sedimentation within Lorestan Province, Iran. We compared two watersheds: Cheshmeh Sardeh Alashtar in North of Lorestan Province, and Helosh Pol Dehtar in south of Lorestan Province. Key gully areas were identified using aerial photographs and topographic maps. Field visits documented the geographic coordinates (GPS) and types of gully heads. Subsequently, a digital slope map with various classes was generated using a Geographic Information System (GIS). By overlaying the slope map with the gully distribution map, we analyzed the frequency of gully types within each slope class for both watersheds. Specific erosion rates of the studied gullies were determined through field measurements of soil erosion from precipitation events. The Kruskal-Wallis test revealed significant differences in specific gully sedimentation across slope classes in both regions. The Mann-Whitney test further pinpointed these differences: in the north, between the 5-10% and >10% slope classes; and in the south, between the 0-5% and 5-10% slope classes compared to the >10% class.