Diachronic Study Of Water Erosion By GIS/RUSLE Approach In The Upper Catchment Of The Sissili (Burkina Faso)

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Résumé

Soil erosion is one of the main sources of land degradation and is an important issue in Burkina Faso, including
the upper Sissili watershed. Among the degradation processes, water erosion is the most important threat to soils. It results
in a reduction of the thickness of the soil and a decrease in the level of organic matter, thus a degradation of their fertility.
The objective of this study is to characterize the dynamics of water erosion in the upper Sissili watershed between 2002 and
2018. The methodology is based on modeling of the different factors of water erosion in a geographic information system.
Factors such as rainfall erosivity, soil erosibility, slope and slope length, vegetation cover and anti-erosion practices are
assessed from the RUSLE universal soil loss equation. The average rate of erosion in the watershed increased from
0.59 t/ha/year in 2002 to 1.22 t/ha/year in 2018, with a total loss of 189,640.05 t/year to 392,835.46 t/year. Five erosion classes
were determined such as 0–1 t/ha/year, 1–5 t/ha/year, 5–10 t/ha/year, 10 to 20 t/ha/year. Class 0 to 1 t/ha/year is the most
represented of the two dates with 83.50% of the total area in 2002, and 61.38% in 2018. Erosion maps are a decision-making
tool and help to guide the various interventions for water and soil conservation.

Mots-clés

Érosion hydrique, RUSLE, bassin versant, Sissili, Burkina Faso