The zoning of gully erosion in the southern regions of Guilan; the overlap index, fuzzy summation and multiplication in the GIS environment

In this research, the zoning of gully erosion in semi-arid regions of Guilan province was investigated. Initially, different land use maps, land units, lithology and slope, extraction plan and work units were selected. In the work units, a control area and three dams were identified. In each unit, profiling and soil sampling and its soil characteristics were evaluated for each unit. Using gully mapping, morphometric and morphometric properties of gully were extracted. In each case, the permeability and the percentage of protection on the soil were studied. After determining the data on the factors affecting erosion (lithology, landslide percentage, soil type, average annual rainfall, type of land use and the percentage of soil protection), we determined the value of each of the mentioned factors and Based on this, the gully erosion zonation map was used using the GIS model or overlapping index model and fuzzy algebraic summation operators and fuzzy algebraic multiplication.