**2.2 Classification of soils and relationship with soil erosion**

Given the objective pursued aimed at identifying the regions participating in the siltation of the Sidi Mhamed Benaouda dam, we have therefore adopted the American classification which is based on a tolerance threshold of 7.4 t/ha/year on average while supporting sustainably a high level of agricultural production and that if the losses exceed 20 t/ha/year, they can become dangerous [58]. We note that this classification has been adopted in Morocco, in the wadi Boussouab watershed, region similar to our study region in terms of climate, vegetation cover and soil substrate.

According to this classification, soil losses will be divided into five categories:


## **2.3 Study area**

Before proposing such a development, it is necessary to give a bibliographical overview of the research work relating to water erosion carried out in this region of interest. The watershed of wadi Mina is located at the northwest of Algeria in the Tellian hill area between 34° 42″ 36″ to 35° 35″ 2″ N latitude and between 0° 23″ 51″ to 1° 8″ 56″ E longitude (**Figure 1**). It lengthens on 90 km on Frenda and Mina mounts at north and on 50 km from the west to east between Bani-Chougrane mounts and the Ouarsenis massive. This watershed covers an area of 4800 km2 [6].

## **2.4 Data used**

The methodology adopted for this study rests on the exploitation of the multisource data (satellite, pedological, climate condition and of the observations to carry out on the ground (in situ)). All these data are integrated and analyzed by the GIS for the cartography of the zones exposed to soil erosion in our study area. 1- Four images Shuttle Radar Topography Mission of resolution 30 m, coordinates: N35E000, N35E001, N34E000 and N34E001, were obtained from the SRTM (2011). 2- Two spectral scenes multi Landsat\_8 OLI/TIRS (Operational Land To color) (Thermal Infrared Sensor) of Path\_197/Row\_035 (LC81970352014077LGN00) and

*Spatial Estimation of Soil Erosion Risk Using RUSLE/GIS Techniques and Practices… DOI: http://dx.doi.org/10.5772/intechopen.96190*

**Figure 1.**

*Study area location map (source: [6]).*

that of Path\_197/Row\_036 (LC81970362014077LGN00) were acquired on March 18th, 2014. These satellite images are uploaded from USGS (2014), with the Geotif format. 3- Observations on the ground, obtained after a descent on the ground in March and April 2014. 4- A detailed pedological map, catchment area of wadi Mina, drawn up by the BNEDER (2004). 5- Rainfall records (daily precipitations) provided by the National office of Meteorology on twenty two stations. They are spread over a period of 36 years (1978–2014) and cover our zone of interest.
