Morphological and Hydrodynamic Changes in the Lower Estuary of the Senegal River: Effects on the Environment of the Breach of the ‘Langue De Barbarie’ Sand Spit in 2003 - The Land/Ocean Interactions in the Coastal Zone of West and Central Africa - page 31

The breach on Langue de Barbarie,
a real threat for the Senegal River estuary

On the Hydrodynamics

Impacts on the Estuary

The main objective that guided the opening of the breach was
the creation of a hydraulic head and a breaking of the sand
spit, enough to discharge all the water that threatened the city
of St. Louis in early August 2003 (Fig. 6 ). Only a few hours
after the opening of the channel, the decrease in the water
level between St. Louis and Diama was nearly 50 cm. The
effectiveness of this opening on flood management no longer
needs to be demonstrated; indeed, no floods of river origin
have been recorded in the lower estuary since 2003, except
overflows of the river in the low zones around the jetties.
In the first months following the opening of the breach, the
fishermen were delighted by the shortening of the river-sea
distance, allowing substantial economies of gasoline. How-
ever, many accidents, nearly always fatal, around the breach

The study of the hydrodynamic modifications, the water
quality and the morphology of the spit will provide some
answers about the projected risk of increased vulnerability
of the environment of the lower estuary and local popula-
tions. A recent study (Kane 2010 ) mentioned the depletion
of some fish species with high economic value. The market-
gardening that was practiced in Gandiolais, already under
limiting conditions before 2003, has now fallen into neglect.
This means that all the difficulties related to the impacts of
the breach on the environment of the Senegal River estuary,
including with the hydrodynamics, the salinization of lands
and waters of Gandiolais region and the morphology of the
lower estuary, are worsening.