Applying the Revised Universal Soil Loss Equation model to land use planning for erosion risk in Brunei Darussalam

Abstract

Soil erosion and the resulting deposition of sediment in rivers and waterways have major environmental, economic and social implications for Brunei Darussalam. This paper demonstrates a tool for incorporating erosion risk into the strategic land use planning process. Through the application of the Revised Universal Soil Loss Equation (RUSLE), we can predict the approximate rate of soil loss and therefore, erosion risk based on a number of factors, including: rainfall, soil type, slope length and gradient and existing ground cover. RUSLE erosion risk maps produced at a resolution of 100 m2 cells across the country as part of the Sedimentation Study of Main Rivers in Brunei Darussalam provide a planning constraints map that can guide decisions on the location of land use activities. Of particular relevance are the RUSLE maps that were compiled under the assumed scenario that land has been cleared ready for development to provide a realistic estimation of erosion risk if land clearing or land use change was to occur. Erosion risk is classified into seven hazard classes based on the predicted rate of soil loss expressed in tonnes per hectare per year. Urban development, mining and forestry are not recommended in areas within erosion hazard classes 4–7 (moderate to extremely high erosion hazard).