Abstract:
Gully erosion is a severe form of soil erosion that results in a wide range of
environmental problems such as dams’ sedimentation, destruction of transportation
and energy transmission lines, decreasing and losing farmland productivity, and land
degradation. The main objective of this study was to map the areas prone to gully
erosion, by using Frequency Ratio (FR) and random forest (RF) models. Moreover;
multi- collinearity analysis was applied and 13 variables among 15 conditioning
factors were selected to train the models for gully erosion susceptibility mapping
(GESM). The conditioning factors include altitude, slope, aspect, plan curvature,
profile curvature, drainage density, topographic wet index, precipitation, normalized
difference vegetation index, land use/land cover, distance from the stream, distance from
road, and soil-related variables. Model prediction potential was evaluated using the
area under the curve (AUC) method. The RF model produced a higher accuracy with
area under curve (AUC) an accuracy value of 89% and FR model prediction
accuracy value was 77%. A detailed accuracy assessment using the Receiver
Operator Characteristics (ROC) validation showed that the RF model is a reliable and
accurate method for GESM than the FR model. Therefore, the RF model is useful in
GESM and helps decision-makers in land-use planning and management. The
outcome of this study can help managers in Aba Gerima to identify gully erosionprone
areas which will help them to mitigate the gully erosion problem and prevent
future gully erosion by taking preventive measures.