A strategy for quantifying turbid-water occurrence possibility based on geologic characteristics and soil erosion in hydrologic basins

Turbid-water problem of reservoirs due to soil erosion causes a major issue in dam operation. This study presents a methodology to quantitatively analyze the occurrence possibility of turbid-water in four hydrologic basins (Sayeon, Degok, Gwangdong, and Imha Dam basins in S. Korea), quantifying the weighting value of turbid-water occurrence in reservoirs. To do this, the study conducted indoor tests, including laser-assisted particle size analysis, X-ray powder diffraction method analysis, and scanning electron microscope, to give the geologic characteristics such as the distribution of soil particle size, settlement time, landslide, and existing sediment yield. The study used RUSLE models to calculate sediment yield on the basis of soil maps, DEMs, and landcover maps as auxiliary data. This study classified factors for evaluating the possibility of turbid-water occurrence into geology, sediment yield, landslide and soil components, and these evaluation items’ weighting and score are presented using the analytic hierarchy process technique. The suggested method is promising in that it can analyze the risk factor of turbid-water occurrence in basins and that can provide a guideline to estimate the turbid-water occurrence of reservoir in dam construction.