Silt accumulates rapidly in Taiwan’s reservoirs given their geographical characteristics, affecting Taiwan’s reservoir capacity and allocation of water resources. In response, the Taiwanese government has set sediment reduction in reservoirs as a policy goal. Thus, the present study established a rapid and rational method for identifying
the main sediment production hotspots in the watershed areas of Taiwan’s reservoirs. This study analyzed three reservoirs
located in the northern, central, and southern regions of Taiwan, namely, the Shimen Reservoir, Wushe Reservoir,
and Nanhua Reservoir. The study divided the watershed areas of these reservoirs into multiple subwatershed areas and
applied the Universal Soil Loss Equation (USLE) to estimate soil erosion from the land surface. Additionally, the study
used the slope-length factor method to calculate the volume of collapsed sediment, along with the slope delivery ratio
and channel delivery ratio, to determine the average annual volume of sediment entering the reservoirs. The assessment
results were compared with actual reservoir dredging and siltation volumes obtained over 10 years, with most of the
results falling within the upper and lower quartiles of the actual data, confirming that the method proposed in this study is reasonable. The identified hotspots should be prioritized in sediment reduction efforts.
Key Words: Reservoir catchment area, Universal Soil Loss Equation (USLE), Sediment delivery ratio (SDR), Sediment
yield production hotspots