The Study of Land Erosion Susceptibility in Bejoshan Chai Catchment Area Using Fuzzy Theory and GIS

Soil erosion is a complex and potentially dangerous geomorphic feature and its rate is a reflection of the type of land management and growth index in any country. For reaching a better and correct land management level it is necessary to recognize sensitive zones of erosion in catchments and their utilization to be based on their potentials and limitations afterwards.In this article we have applied Fuzzy theory operators to recognize the areas susceptible to erosion and their zoning according to the erosion potentiality. Results obtained are closer to the reality due to the lack of firmness and flexibility of classic methods in valuing the data. The total input data used in this study include: lithology, the present land uses and vegetation cover, topographic gradient, and the density of runoff drainages.Study of the nature and structure of Fuzzy logics and the accordance of output maps of Fuzzy operators with the erosion realities obtained from field works indicated that:In the zoning of lands susceptible to erosion, the Fuzzy deterministic operator has a higher utility sue to better specification of lands susceptible to erosion compared to Fuzzy multiplication operator. Therefore, we propose higher sensitivities on the issues such as land use, utilization management and water, soil, and plant conservation and the possible costs imposed to managers, and the method proposed is Fuzzy added up method for the recognition of erosion susceptible areas.