Assessment of soil erosion extent using RUSLE model integrated with GIS and RS: the case of Megech-Dirma watershed, Northwest Ethiopia.

Abstract

Soil erosion valuation at a spatial scale is crucial for assessing natural resource quality in a farming country like Ethiopia. The study's goal was to determine the rate of soil erosion in the Megech-Dirma catchment in Northwest Ethiopia using the Revised Universal Soil Loss Equation model aggregation with Geographic Information System and Remote Sensing. Sediment yield and transport were also estimated using sediment delivery ratio. Revised Universal Soil Loss Equation model data inputs included precipitation data for the R value, soil data for the K value, land cover data from satellite images for the C and P value, and topographical data from a Digital Elevation Model for the LS component. It was completed using the ArcGIS 10.4 software. The mean annual soil loss is 110.60 t ha-1yr-1. Each year, a total of 8499.74 t ha-1yr-1 of soil eroded and on average resulting in 1605.30 t/km2/yr, sediment material has been transported to the stream channels and deposited with a sediment delivery ratio of 1.87. The strength of soil erosion in the area is divided into six categories. The erosion rate classes were 46.38 percent (0-12 t ha-1yr-1) low, 13.63 percent (12-20ha-1yr-1) moderate, 9.22 percent (20-35ha-1yr-1) high, 12.30 percent (35-50ha-1yr-1) very high, 7.20 percent (50 up to 100ha-1yr-1) severe, and 11.27 percent (>100ha-1yr-1) very severe erosion. According to erosion severity, 46.38 percent of the watershed is at risk of low erosion, while 11.27 percent is at risk of extremely severe erosion. The north and northeastern sections of the watershed have a moderate to extremely severe erosion risk due to steep slopes, high rainfall, and weak conservation measures. The severely eroded parts of the plateau and steep portions are proposed to be covered by plantation, stone bund, and check dam constructions.