Application of geospatial technology coupled with fuzzy logic operations in mapping soil-erosion critical zones: the case of guder sub-basin, upper blue nile basin, ethiopia

Abstract

The study attempted to map soil-erosion critical zones in the Guder sub-basin in Ethiopia. To map soil erosion sensitive areas, a digital elevation model (12 m × 12 m spatial resolution), precipitation data covering 30 years, soil type, and land use were utilized as inputs. Fuzzy logic techniques based on Geographic Information Systems (GIS) were integrated and analyzed on the ArcGIS 10.5 platform. Five contributing variables were considered as potential causes associated to soil-erosion in the study. Slope, land use, soil type, rainfall, and compound topographic index are the variables. Fuzzy membership values were constructed to generate the rankings of each parameter and their subclasses. Researcher and expert judgment with a survey of the previous studies were used to determine the membership value for each thematic layer and their classes. As a result, the soil-erosion zone map revealed very high, high, moderate, low, and very low erosion susceptibility with areal percentage distribution of 4.96%, 67.48%, 25.41%, 1.88%, and 0.27%, respectively. The study's findings were validated using cross-relationship of the contributing elements and the final map, which revealed strong relationships. The study's findings would help decision-makers and policymakers plan and implement effective watershed management strategies in highly vulnerable locations to soil erosion. Fuzzy logic approaches, when combined with GIS, have been proven to be a basic tool for determining erosion important locations. The final soil erosion map revealed that the majority of the studied areas were prone to soil erosion as a result of agricultural practices, necessitating integrated soil and water conservation practices.