Assessment of sediment yield in Thailand using revised universal soil loss equation and geographic information system techniques

Soil is one of the most important natural resources on Earth. Information on soil loss is important to support agricultural productivity and natural resource management. Therefore, this research aimed to estimate and map mean annual soil erosion and sediment deposition using a geographic information system (GIS). The soil loss in each grid cell was analysed by the revised universal soil loss equation (RUSLE) model. The parameters of the RUSLE including rainfall, soil type, and land use were calculated in each grid cell from a digital elevation model with of 1-km² resolution. Furthermore, sediment deposition was derived from the RUSLE model and used in GIS software to generate soil loss capacity maps. The results show that soil erosion occurred over all parts of Thailand, especially in the northern and southern parts due to the topography, geology, and land cover. The sediment was deposited in grid cells where the elevation was low, primarily near rivers. The results of this research support local land development policies that are implemented to control sediment yields during development.