Mapping of monthly soil erosion risk of mainland Mauritius and its aggregation with delineated basins

This paper reports the mapping of monthly soil erosion risk on Mauritius which was carried out using GIS, decision rules and readily available data namely, monthly rainfall depth, soil types, slope and land cover. Slope and soil were first combined to produce soil erosion susceptibility followed by land cover to produce erosion sensitivity, and then rainfall to produce erosion risk. The high erosion areas of the Island have been extracted from the soil erosion risk maps, whereby these areas can face land degradation problems and can be responsible for sediment discharge into wetlands located at the outlet of drainage basins. As such, drainage basins have been delineated using automatic catchment delineation tools and their percentage of high erosion areas computed. Basins with the greatest percentage of high erosion areas and particularly those that directly have a wetland at the outlet can be given priority for soil and water conservation efforts. The mapping reported in this paper can be adapted to other countries which need an erosion assessment for the identification of high erosion areas and priority action areas.