*4.3. Landscape Pattern Index and Sediment Yield*

A landscape pattern index is used to describe the type and spatial arrangement of the landscape by considering different features such as size, shape, and connectivity [44]. A series of work has been conducted to investigate the relationship between soil erosion and landscape patterns (e.g., [45–47]). In this study, we introduce a landscape pattern index following Zhou [47]. The index (*SI*, Equation (13)) considers the soil erodibility factor (*K*), the cropping-management factor (*C*) and the topography factor slope (α, ◦).

$$SI = \mathbb{C} \times \mathbb{K} \times \sin \alpha \tag{13}$$

In this study, *C* and *K* values are calibrated over GCEW manually. Topographic slope is calculated using ArcGIS on the digital elevation grid of the study area with a resolution of 50 × 50 m. Then the *SI* is calculated over GCEW following Equation (13). Furthermore, we analyzed the relationship between *SI* and the magnitude of the soil erosion simulated by our model during the calibration event. Figure 11a–d shows the spatial distribution of *C*, *K*, slope and *SI* over GCEW. Figure 11d exhibits the net erosion and deposition over the study area during the calibration event.

To investigate the relationship between *SI* (Figure 11d) and net erosion/deposition (Figure 11e), we conducted a correlation analysis using the Spatial Analyst Tools of ArcGIS. With a correlation coefficient of−0.017, landscape pattern and soil erosion show no significant linear relation. This indicates that during a storm event with a duration of hours over GCEW, the landscape pattern might not be the dominating factor controlling the spatial distribution of soil erosion.

**Figure 11.** *C* value (**a**), *K* value (**b**), slope (**c**), and *SI* (**d**) over GCEW, and Net Erosion (−)/Deposition (+) (**e**) during calibration event over GCEW.
