## 3 Results and Analysis
### Slope and Slope Direction Analysis  
The maximum slope value in the study area was 56.59\({}^{\circ}\), and the mean value was 15.540\({}^{\circ}\). According to the statistics in Figure 7, it was found that the distribution of slopes at all levels in the study area was not uniform, and the slope structure was mainly dominated by gentle slopes (5\({}^{\circ}\) to 15\({}^{\circ}\)) and slopes (15\({}^{\circ}\) to 25\({}^{\circ}\)). Among them, the area of gentle slopes  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Level** & **I** & **II** & **III** & **IV** & **V** & **Total** \\ \hline Number of rivers & 144 & 64 & 41 & 23 & 9 & 281 \\ Length of river (km) & 21.420 & 12.574 & 7.982 & 3.307 & 1.260 & 46.519 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Linear measurement results of the water system network within the inner ring line.  
Figure 6: Classification of the water system network within the inner ring of the study area.  
is the largest, with an area of 14.595 km\({}^{2}\), accounting for 42.372%. Slopes come next with an area of 12.958 km\({}^{2}\), accounting for 37.589%. Steep slopes have an area of 3.402 km\({}^{2}\), accounting for 9.876%. The remaining gentle slopes, steep slopes, and sharp slopes are fewer, with a combined area of 10.163%.  
The slope classification map (Figure 8a) shows differences in the distribution of slopes between the inner and outer parts of the inner ring. Areas with large slopes (>35\({}^{\circ}\)) are represented on the map as a ring with a notch at the base and are mainly distributed in the outer areas of the inner ring. The terrain extends from ridges to valleys with dramatic slope shifts and interspersed ridges and valleys. Several steep and sharply steep slopes are also distributed in the eastern region. The terrain slopes in the inner loop show large slope values (>35\({}^{\circ}\)) on the banks on both sides of the main stem of the water system, which may be related to erosion from surface runoff. The remainder consists of slopes, gentle slopes, and a few flat slopes.  
According to regulations and related studies [36], it is known that areas with a slope greater than 25\({}^{\circ}\) are areas with a high incidence of landslide hazards. That is to say, under specific environmental and meteorological conditions, areas within this slope range are more susceptible to landslides. The landslide hazard-prone area in the study area is 9.876%,  
Figure 8: Distribution of microtopographic feature parameters (**a**) slope and (**b**) slope direction.  
Figure 7: Slope distribution and percentage share of the study area at all levels.  
mainly distributed in the outer slopes of the inner ring road, the riverbanks on both sides of the main streams of the water system, and the small mountains in the east.  
Statistically (Figure 9), the average slope direction of the study area is 184.797\({}^{\circ}\) (southward). The slope direction in the study area is mainly dominated by five directions: southeast, south, southwest, west, and northwest, with a combined area share of 70.298%. Among them, the southeast slope direction accounted for the most significant proportion at 16.743%. The planar area accounts for a minor proportion at 1.046%, mainly the Dasha River tailings pond located in the southwestern part of the study area.  
From the slope orientation distribution map (Figure 8b), it can be seen that there are several dominant directions of slope orientation in the study area, and the distribution of slope orientation is uneven and asymmetrical. It also implies that the topography of the study area is complex, containing landform types such as flats, hills, and mountains. Among them, the distribution of slope directions reflects the direction of ridges, and ridgelines are often the dividing line of slope directions. In particular, the ridges and valleys on the outer side of the inner ring show a radial and outward-expanding character.