Abstract:
The issue of desertification is
a pressing concern for many vulnerable
regions, with consequences that extend far
beyond their borders. It is a silent force that
not only contributes to global climate change
by releasing stored carbon from vegetation
and soil but also compounds the ongoing
environmental challenges we face on a global
scale. In Morocco, the effects of these climate
changes are already noticeable, particularly in
terms of water scarcity due to reduced rainfall
and rising temperatures. This, in turn, leads to
soil drying and an increased risk of
degradation. The Oum Er-Rbia watershed
(upstream of Ouled Sidi Driss) is one of the
basins affected by this issue, covering an area
of 11,152 km² and spanning three topographic
units (the Middle Atlas Mountains, the
Phosphate Plateau and the Tadla Plain). This
topographic diversity causes regional
variation in the sensitivity to desertification.
Therefore, this study aims to evaluate the
sensitivity to desertification in this watershed
by using the MEDALUS model
(Mediterranean desertification and land use),
which calculates the Desertification
Sensitivity Index (DSI) through the
composition of four indices: the Soil Quality
Index (SQI), the Vegetation Quality Index
(VQI), the Climate Quality Index (CQI) and
the Land Use Quality Index (LUQI). The
results show that the critical and highly
sensitive zones represent 44% and are located
at the northeast and west ends of the
watershed. By contrast, the unaffected zones
represent 12% of the total area of the
watershed and correspond to the upstream
area, where the climate, vegetation and land
use systems are of good quality, providing
effective protection for the land. To reduce the impact of this phenomenon, we have
proposed some potentially impactful
development actions based on land use and
the results obtained.
