Figure 13. Spatial distributions of (a) potential maximum
erosion, (b) slope, and (c) risk of sediment disaster in the catchment
area.
The risk of sediment disasters in the Chenyulan River catchment area
could be determined using the potential maximum erosion and slope. To
explore the difference between analytical results and the actual
situation, actual landslide data were investigated. This study ranked
the risk of sediment disaster of 269 subdivisions from largest to
smallest, and the first 1, 5, 10, 20, 40, 60, 80, 100, 120, 140, 160,
180, and 196 subdivisions were extracted to estimate their landslide
rates (cumulative landslide area of the subdivision/total landslide area
in the catchment area). Figure 14 shows that in the top 20 subdivisions,
the cumulative landslide area accounted for 40.1% of the total
landslide area in the catchment area. For the top 196 subdivisions, the
cumulative landslide area accounted for 100% of the total landslide
area in the catchment area. The results indicated that the cumulative
number of subdivisions was positively correlated with the landslide
rate. In areas with limited data, the relational curve between the
cumulative number of subdivisions and landslide rate could be used to
determine subdivisions with management priorities. This study
investigated the number of subdivisions and their spatial distribution
in a 70% landslide rate scenario; Figure 14 shows that the number of
subdivisions corresponding to this rate was 80. Figures 15 and 16
indicate that the results between the selected subdivisions and actual
landslides were mostly consistent.