The application of an expert knowledge‐driven approach for assessing gully erosion susceptibility in the subtropical Nigerian savannah

Abstract

This study assessed gully erosion susceptibility in Southern Gombe State, Nigeria. The objectives of the study were to: (1) prepare gully inventory of Southern Gombe State, (2) apply the Analytical Hierarchy Process to assess the contribution of gully erosion predisposing factors, and (3) produce a gully erosion susceptibility map of Southern Gombe State. Based on geomorphological study involving interpretation of Google Earth images and field surveys, 127 gullies were identified and 13 gully erosion predisposing factors assumed to influence gully erosion susceptibility were selected. Identified gullies were randomly split into training (89 or 70 per cent) and validation (38 or 30 per cent) datasets. The contribution of each gully erosion predisposing factor was obtained using the Analytical Hierarchy Process. The results indicated that slope (0.130), stream density (0.121), and distance from stream (0.121) play crucial roles in gully erosion susceptibility. By overlaying the gully erosion susceptibility factor maps, a gully erosion susceptibility map was created. A natural break method was then used to classify gully erosion areas into relatively safe (6.04 km2), less susceptible (3332.46 km2), moderately susceptible (1811.49 km2), highly susceptible (1146.35 km2), and extremely susceptible (1726.77 km2) categories. Field verification confirmed that the map accurately classified 92.11 per cent of the validation datasets, signifying the Analytical Hierarchy Process as a reliable method for gully erosion susceptibility assessment. The created gully erosion susceptibility map can assist land planners to identify critical gully erosion areas where prevention and mitigation actions should be implemented.

Spatial prediction of soil erosion risk using knowledge-driven method in Malaysia’s Steepland Agriculture Forested Valley

“…Many researchers have studied the impact of slope aspects on soil erosion (Gabarrón‐Galeote et al, 2013 ; Tehrany et al, 2017 ; Das et al, 2020 ; Aslam et al, 2021 ). Due to its relationship with the duration of sunlight exposure, moisture retention, slope distribution vegetation cover type, and evapotranspiration, slope aspect indirectly affects soil erosion processes (Gideon et al, 2021 ). The steepness and length of a slope are critical factors that control surface runoff and erosion (Bryan & Poesen, 1989 ).…”

“…To date, the AHP technique has been widely integrated with geospatial technology such as GIS and RS for various studies related to environmental issues such as soil erosion (Mushtaq et al, 2023 ; Tairi et al, 2019 ) and landslide hazard (El Jazouli et al, 2019 ; Kumar & Anbalagan, 2016 ). The AHP technique uses subjective assessment rules to identify vulnerable areas (Gideon et al, 2021 ).…”

Analytical techniques for mapping multi-hazard with geo-environmental modeling approaches and UAV images

“…Based on the literature review, the main covariables that trigger the occurrence of collapsed pipes and gully heads are broken up into four groups, including human factors (land use), topologic (altitude, slope degree), soil properties (calcium carbonate equivalent (CCE), organic carbon (OC), exchangeable sodium percentage (ESP), silt content, bulk density, soil stability), and hydrology (stream distance, stream density) 5 , 10 , 45 – 50 . Landslides are affected by a collection of anthropological (land use and road distance) and geo-environmental “(plan curvature, distance to streams, altitude, drainage density, profile curvature, topographic wetness index, and slope degree)” variables 44 , 45 .…”