Potential contribution of land cover change on flood events in the Senegal River basin

The increase in flood events observed in West African countries, and often in
specific river basins, can beinfluenced by several factors, including anthropogenic
land use and land-cover changes. However, the potential contribution of land
cover changes to flood events still needs to be explored, especially in West
Africa. Here, the fully coupled atmosphere-hydrology WRF-Hydro system,
which comprises an atmospheric model and additionally incorporates the
surface, subsurface, overland flow, and channel routing, is used to investigate
the potential impact of a land cover change scenario on flood events in the
Senegal River basin. The simulation was performed from 2010 to 2020, with a
calibration period spanning from 2011 to 2012 and a validation period from 2013
to 2020. Several skill scores, including Nash-Sutcliffe Efficiency (NSE), BIAS,
and Kling-Gupta Efficiency (KGE), were utilized to assess the calibration and
validation performances. Additionally, two planetary boundary layer schemes
(PBL5 and PBL7) were used to determine their associated uncertainty. Our results
show that the best calibration results (NSE = 0.70; KGE = 0.83; PBIAS =−7% and
... mehr
BE = 0.67) in the Senegal River basin are obtained with PBL5 when the calibration
is performed with a SLOPE parameter 0.03. A similar good performance was
also obtained for the validation with NSE = 0.74, KGE = 0.84, and PBIAS =−8%.
Likewise, our findings indicate that converting savanna to woody savannas can
elevate water resources, with a 2% rise in precipitation and a 4% increase in
runoff. This transition also correlates with an increase in moderate flood events
(3500–4000 m$^3$/s), a decrease in severe floods (4000–5000 m$^3$/s), and their
associated occurrence of extreme floods (>5000 m$^3$/s) in the Senegal River
basin.