Spatial Modeling of Soil Erosion Risk and Its Implication for Conservation Planning: the Case of the Gobele Watershed, East Hararghe Zone, Ethiopia

Abstract

Abstract:Soil erosion by water has accelerated over recent decades due to non-sustainable land use practices resulting in substantial land degradation processes. Spatially explicit information on soil erosion is critical for the development and implementation of appropriate Soil and Water Conservation (SWC) measures.The objectives of this study were to estimate the magnitude of soil loss rate, assess the change of erosion risk, and elucidate their implication for SWC planning in the Gobele Watershed, East Hararghe Zone, Ethiopia. Applying remote sensing data, the study first derived the Revised Universal Soil Loss Equation (RUSLE) model parameters in an ArcGIS environment and estimated the soil loss rates. The estimated total soil loss in the watershed was 1,390,130.48 tons in 2000 and 1,022,445.09 tons in 2016 with a mean erosion rate of 51.04 t ha −1 y −1 and 34.26 t ha −1 y −1 , respectively. The study area was divided into eight erosion risk classes ranging from very low to extremely high. We established a change detection matrix of the soil erosion risk classes between 2000 and 2016. The change analysis results have revealed that about 70.80% of the soil erosion risk areas remained unchanged, 19.67% increased in total area, and 9.53% decreased, showing an overall worsening of the situation. We identified and mapped areas with a higher and increasing erosion risk as SWC priority areas using a Multi-criteria Decision Rules (MCDR) method. The top three priority levels marked for the emergency SWC measures account for about 0.04%, 0.49%, and 0.83%, respectively. These priority levels are situated along the steep slope areas in the north, northwest, south, and southeast of the Gobele Watershed. It is, thus, very critical to undertake proper intervention measures in upslope areas based on the priority levels to establish sustainable watershed management in the study area.

Prediction of Soil Erosion in Pansoon Sub-basin, Malaysia using RUSLE Integrated in Geographical Information System

“…The LS factor is important because it shows the effect of topography and terrain on the erosion event. Generally, higher slope length and slope steepness will result in higher soil erosion rate (Woldemariam et al 2018). LS factor in Pansoon sub-basin is dominated by low LS factor (74% of below than 5) which means that it has less contribution to the erosion risk.…”

Effect of Land Use and Land Cover Change on Soil Erosion in Erer Sub-Basin, Northeast Wabi Shebelle Basin, Ethiopia

“…Soil erosion can also cause severe environmental problems, including soil and water degradation, a decrease in land productivity, and eutrophication and sedimentation of water bodies [3][4][5][6][7][8][9][10][11]. Numerous studies have reported that the magnitude of soil erosion rates has been accelerating worldwide due to land use and land cover change (LULCC) and inappropriate land use and management practices resulting in widespread land degradation process [2][3][4][5][12][13][14][15][16][17][18]. The global annual average potential soil loss due to water-caused erosion was estimated at 35 billion tons in 2001 [4].…”

“…In connection to this, the Food and Agriculture Organization (FAO) of the United Nations and Intergovernmental Technical Panel on Soils [14] stated that "if action is not taken to reduce erosion, total crop yield losses projected by the year 2050 would be equivalent to removing 1.5 million km 2 of land from crop production-or roughly all the arable land in India". In the developing countries where the overall economy and the livelihood of a majority of the population depend on the productivity of their land, the displacement of the most productive topsoil layer by erosion and a poor conservation practices have resulted in the reductions in agricultural production and land productivity potential and contributing to food insecurity [18,19].…”

“…Assessing and mediating the untoward effects of soil erosion risk while increasing productivity of land resources has become the key concern of policymakers and conservation planners around the world [5,11,[15][16][17][18][41][42][43]. In order to control erosion risk at river basin and watershed scales, there is a need to predict spatially distributed rates of soil erosion and sediment yield [18,44,45].…”

“…Assessing and mediating the untoward effects of soil erosion risk while increasing productivity of land resources has become the key concern of policymakers and conservation planners around the world [5,11,[15][16][17][18][41][42][43]. In order to control erosion risk at river basin and watershed scales, there is a need to predict spatially distributed rates of soil erosion and sediment yield [18,44,45]. Given the complexity of interplays among and within the physical and hydrological factors that involved soil erosion (e.g., topography, rainfall, vegetation cover, soil, and land use) and soil conservation practices, consistent estimation of soil loss rates in the river basins and watersheds remains a key challenge in soil erosion study [17,[46][47][48].…”