Assessment of Gully Erosion Zonation Methods (Case study: Abgendi Watershed)

Surface. The development of gullies causes the loss of a great amount of soil and could be considered as one of the principal causes of geo-environmental degradation. In this research FAZI model introduced for gully erosion zonation in arid and semiarid area considered to calibration and validation in Kahkiloeh and Boyerahmad Province. Therefore, the ABGANDI watershed were selected by consideration of gully erosion distribution in Kahkiloeh and Boyerahmad Province. In this region the maps of lithology, slope, soil, rainfall, land cover and land use were extracted and thus selected the working units. In each of the units, gullies morphometric, soil penetration condition and soil conservation percent characteristics with survey investigated. Also, determinates the quantity value of six maps model input layer include (lithology, percent of slop, soil type, annual average precipitation, land use and percent of soil conservation) was determined. Finally, gully erosion mapping using overlay index, fuzzy algebraic sum, fuzzy algebra product and fuzzy gamma in GIS performed. Obtained result of different regions indicated that the fuzzy gamma model 0.8 is the proper method to gully erosion zoning in studied watershed.