**Topographic (LS) Factor**

The analyzed LS factor with the slope ranges is presented in **Table 3**. After generating the flow accumulation the topographic factor (LS) factor in the GIS environment was used [30].

$$\text{LS} = \text{(Flow accumulation} \ast \text{Cell size} / 22.13) \text{\textdegree 0.4} \ast \text{(sin} \, (\text{slope} / 0.0896) \text{\textdegree 1.3}) \tag{3}$$

Where flow accumulation refers to the number of cells contributing to flow into a given cell and cell size is the size of the cells being used in the grid-based representation of the landscape [30, 34] (**Figure 6**).

#### **Crop Management (C) Factor**

The C-factor was given based on the estimated value that was developed by [8]. The mean value of different crops (C = 0.16) had been taken for the C - value for croplands. Besides, the C-value for vegetation was considered as C = 0.02 and for grazing land was C = 0.03 and for degraded land was C = 0.2. Thus, the Cvalue was applied to the land use map of the 2018 land sat image. After generating the classified land sat image of 2018, the format was changed into a vector and a corresponding C-value was assigned to each land use type using the editing menu of Arc GIS 10.3 from the C-value adopted by Hurni [8] for the RUSLE model.

## **Conservation Support Practice (P) Factor**

The data related to management practices were collected during the fieldwork. Values for this factor were assigned considering local management practices and


#### **Table 2.**

*K-values of soil colors in the study areas.*


**Table 3.** *RUSLE LS factor.* *Remote Sensing and GIS-Based Soil Loss Estimation Using RUSLE in Bahir Dar Zuria District… DOI: http://dx.doi.org/10.5772/intechopen.95393*

based on values suggested in Hurni [8]. The result land cover map and the associated P-factors were used to generate a grid surface for the P-factor, utilizing Arc GIS 10.3 spatial analyst. Soil bund, bench terrace, grassed waterways, grassed strips, and area closure are the dominant management practices. The bench terraces and area closures are mainly found at the higher elevation, whereas soil bund and grassed waterways are distributed in the low laying areas.

#### **Overlay**

The RUSLE is an index method that includes factors that represent how land cover, climate, soil, topography, and land use affect soil erosion caused by raindrop impact and surface runoff. To assess the effect of these parameters at the same time, the overlay of all factors in a single scene was made. This was done utilizing Arc GIS software (**Figure 7**).
