Management of a Tropical River: Impacts on the Resilience of the Senegal River Estuary

Abstract

Tropical rivers are under constant pressure and are subjected to flood control policy and planning. The Senegal River has been, for more than thirty years, under multiple types of management and planning. That has become recently more important because of significant hydro-climatic variability that has occurred during recent years. Higher levels of winter rainfall have resulted in frequent occurrence of flooding which guided Senegalese authorities to create an artificial opening on the sand of spit so-called Langue de Barbarie. The major consequence of this has been the closing of the old mouth of the Senegal estuary 25 km downstream of the town of Saint-Louis. However, two new mouths have opened themselves recently within 150 m of the current mouth. The increasing vulnerability in the Senegal River estuary has been one of the main impacts of the watershed management of the Senegalese northern River accordingly. The developments of Senegal River management policy have been based on the concept of remedying the consequences of climatic events; then, the utilization of water resources presented risks that are far greater than expected.

Monitoring and Forecasting of Coastal Erosion in the Context of Climate Change in Saint Louis (Senegal)

“…During high tides, ocean levels rise dramatically, whereas river flows are significantly evacuated during low tides. The area is under jeopardy from increased coastal erosion [17].…”

“…Subsequently, a second method was adopted, leveraging contemporary geospatial tools such as satellite imagery, cadastral maps, and aerial photographs [47]. Numerous studies on shoreline dynamics in the Saint Louis region, particularly within the Langue de Barbarie (LB), have utilized modern geospatial tools, as evidenced by previous research [5,[16][17][18][19]21,25]. This study builds upon previous examinations of LB's coastline dynamics, encompassing both pre-and post-implementation of the breach (Figure 2).…”

“…There is a large rise in seawater during high tides, with significant evacuation of river flows during low tides. The area is being threatened by increased coastal erosion [17]. The breach caused an increase in the salinity of the water table, making the gardens unusable.…”