72
C.T. Koulibaly, J.O. Ayoade
Figure 13 shows that even if important shoreline protection efforts have been
felt in Rufisque, the process of coastal erosion is still important on the field as shown
by these abandoned buildings collapsing into the sea, while in the fishing village of
Bargny Guedj the situation is almost apocalyptic.
Long-term analysis of coastline changes over the Senegalese coastline us‑
ing DSAS has proven that the south west coast of Senegal (Casamance), where
a study carried out from 1968 to 2017, is also subjected to two major trends char‑
acterized by a global accretion from 1968 to 1986 followed by a period of beach
decline (1986–2017) with an attenuation of erosion process occurring between 2004
and 2017 [36]. Along the North West coast (Saint-Louis), both processes of retreat
and accretion were detected from 1978 to 2018 with a rate of coastal erosion rang‑
ing from −0.1 to −35.36 m/year and accretion from 0.11 to 18.34 m/year [37]. The
same study showed that the coastline of Saint-Louis is also subject to strong spatial
variability; some areas located northward such as the fishing villages of Guet-Ndar,
Ndar Toute and Goxumbacc were affected with shoreline retreat of −1.53 m/year
(Guet-Ndar), −2.94 m/year (Ndar Toute) and −1.9 m/year (Goxxumbacc) respective‑
ly while the highest rates of erosion (from −9.39 to 35 m/year) have been record‑
ed around the new mouth [37]. Ultimately, Bakhoum et al. [38] revealed a strong
spatial temporal variability of the coastline of Dakar from 1954–2015, with a dom‑
inance of eroded surfaces over accreted areas attesting to a negative sedimentary
budget. On the same note, Biondo et al. [39] recorded EPR values ranging from −0.51
to −2.92 m/year along the Urban Mediterranean beaches such as the gulf of Cagliary
from 1954 to 2016.
These long term observations can be compared to the short term assessment
of coastline changes showing an alteration of about 21,847.978 m of the coastline
with a rate of −3.05 m from 1990 to 2010 in Ghana [40]. It has also been shown that
the coastline of Grand Lahou (Ivory coast) was subject to maximum rate of erosion
of 2.09 m/year from 1998 to 2004 [33].
In any case, DSAS has been proven to be a successful tool that definitely contrib‑
utes to short and long term analysis of coastal erosion emanating from natural and
anthropogenic pressure, while the most highlighted ones are more or less related
to sea level rise, slope instability, rapid building expansion. The coastline from Ru‑
fisque to Toubab Dialaw is experiencing an ongoing urbanization process inducing
huge demand for construction materials. Urbanization and economic activities exert
considerable pressures on coastal areas, including coastal engineering works, reg‑
ulation of river basins (in particular the construction of dams), dredging, clearing,
extraction of marine aggregates, sand, natural gas and water and land occupancy
demands [8]. Armah [40] pointed out that in addition to natural factors, sand min‑
ing, infrastructures and other commercial and social activities are among the major
drivers of coastal erosion in Ghana. Urbanization also reduces the surface of coastal
ecosystems and deeply impacts their natural functioning by contributing to the phe‑
nomenon of sediment deficit through sand beach extraction. Diallo [18] mentioned
C.T. Koulibaly, J.O. Ayoade
Figure 13 shows that even if important shoreline protection efforts have been
felt in Rufisque, the process of coastal erosion is still important on the field as shown
by these abandoned buildings collapsing into the sea, while in the fishing village of
Bargny Guedj the situation is almost apocalyptic.
Long-term analysis of coastline changes over the Senegalese coastline us‑
ing DSAS has proven that the south west coast of Senegal (Casamance), where
a study carried out from 1968 to 2017, is also subjected to two major trends char‑
acterized by a global accretion from 1968 to 1986 followed by a period of beach
decline (1986–2017) with an attenuation of erosion process occurring between 2004
and 2017 [36]. Along the North West coast (Saint-Louis), both processes of retreat
and accretion were detected from 1978 to 2018 with a rate of coastal erosion rang‑
ing from −0.1 to −35.36 m/year and accretion from 0.11 to 18.34 m/year [37]. The
same study showed that the coastline of Saint-Louis is also subject to strong spatial
variability; some areas located northward such as the fishing villages of Guet-Ndar,
Ndar Toute and Goxumbacc were affected with shoreline retreat of −1.53 m/year
(Guet-Ndar), −2.94 m/year (Ndar Toute) and −1.9 m/year (Goxxumbacc) respective‑
ly while the highest rates of erosion (from −9.39 to 35 m/year) have been record‑
ed around the new mouth [37]. Ultimately, Bakhoum et al. [38] revealed a strong
spatial temporal variability of the coastline of Dakar from 1954–2015, with a dom‑
inance of eroded surfaces over accreted areas attesting to a negative sedimentary
budget. On the same note, Biondo et al. [39] recorded EPR values ranging from −0.51
to −2.92 m/year along the Urban Mediterranean beaches such as the gulf of Cagliary
from 1954 to 2016.
These long term observations can be compared to the short term assessment
of coastline changes showing an alteration of about 21,847.978 m of the coastline
with a rate of −3.05 m from 1990 to 2010 in Ghana [40]. It has also been shown that
the coastline of Grand Lahou (Ivory coast) was subject to maximum rate of erosion
of 2.09 m/year from 1998 to 2004 [33].
In any case, DSAS has been proven to be a successful tool that definitely contrib‑
utes to short and long term analysis of coastal erosion emanating from natural and
anthropogenic pressure, while the most highlighted ones are more or less related
to sea level rise, slope instability, rapid building expansion. The coastline from Ru‑
fisque to Toubab Dialaw is experiencing an ongoing urbanization process inducing
huge demand for construction materials. Urbanization and economic activities exert
considerable pressures on coastal areas, including coastal engineering works, reg‑
ulation of river basins (in particular the construction of dams), dredging, clearing,
extraction of marine aggregates, sand, natural gas and water and land occupancy
demands [8]. Armah [40] pointed out that in addition to natural factors, sand min‑
ing, infrastructures and other commercial and social activities are among the major
drivers of coastal erosion in Ghana. Urbanization also reduces the surface of coastal
ecosystems and deeply impacts their natural functioning by contributing to the phe‑
nomenon of sediment deficit through sand beach extraction. Diallo [18] mentioned