The Vulnerability Of Climate Change In The Mediterranean Region

1971 Words 8 Pages
Introduction:
Water and soil, are vital resources. In the arid region, they are experiencing a high degradation in quantity and quality by water erosion. the latter is a natural phenomenon, that evolves with the anthropic evolution and the climate severity, recent studies on the vulnerability to climate change in the Mediterranean region, indicate a trend towards increased aridity which accelerating water erosion (Berkane and Yahiaou 2007; Souadi 2011).
Soil erosion by rainfall and runoff is a widespread phenomenon in the different Mediterranean countries (Bou
Kheir et al. 2001), it is a very complex phenomenon, because of its irregular, random nature and its spatiotemporal discontinuity.
The topographic and climatic factors, associated with
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2017) For the calculation of topographic factor (LS).
퐿푆 = (푓푙표푤 푎푐푐푢푚푢푙푎푡푖표푛 ×
푟푒푠표푙푢푡푖표푛
22.1
)

× (0.065 + 0.045 × 푆 + 0.0065 × 푆2)
With ‘S’ is the slope (%) and ‘m’ is a parameter relative to each class of slope (W. H. Wischmeier and Smith
1978) (Table 3).
C factor:
The vegetal cover factor (C) is considered as the second major factor (after topography) controlling soil erosion
(Benchettouh et al. 2017), The factor C indicates the degree of soil protection by vegetation cover. The latter intercepts the rainfall, increases the infiltration and reduces the rainfall kinetic energy before influencing the soil surface (Mhangara et al. 2012). Soil erosion decreases exponentially with the increase in vegetation cover (Jiang et al. 2015).
In the RUSLE models, the cover factor (C) is an index, which reflects, based on the land use, the effect
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This factor is used to express the effect of vegetation cover of the watersheds. The Normalized Difference Vegetation Index (NDVI) it is one of the most commonly used methods to determine the C-factor.
In this study, the Normalized Difference Vegetation Index (NDVI) data (period 2017) generated by Satellite
Landsat 8. with a spatial resolution of 30 m was used to estimate the C factor and explain the effect of differences in vegetation cover on the Loss of soil, the (NDVI) was calculated from a combination of red and infrared bands .
In order to estimate the values of the C-factor, some authors (Toumi et al. 2013) have used the regression between two extreme values of NDVI, the regression line found is
푐 = 0.9167 − 푁퐷푉퐼 × 1.1667
P factor:
P factor indicates erosion conservation practices on the annual soil loss from the watershed; it reflects the effects of practices that will reduce the amount of runoff and their velocity, thereby, reducing the effects of water erosion. According to (Elaloui et al. 2017) the cultures contour in alternating strips or terraces, reforestation benches, mounding and ridging are the most effective soil conservation

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