A Numerical Forecast of Shoreline Evolution after Harbour Construction in Nouakchott, Mauritania
Résumé
The construction of a deepwater harbour jetty near Nouakchott, the capital city of Mauritania, significantly modified the southward longshore sand transport, causing severe shoreline recession. The UNIBEST numerical model was used to study the actual impact of this infrastructure and assess the future shoreline evolution. The results, validated by field measurements, indicate that the shoreline evolution rate has undergone a 10-fold increase after harbour construction, with significant accretion to the north and severe erosion to the south of the harbour. Such findings are well documented by past and present observations. Model predictions also suggest that erosion south of the harbour may lead in the near future to inundation of parts of Nouakchott lying below sea level. Finally, this type of numerical hindcast–forecast approach, used for a simple sediment transport case, is useful for the prediction of future shoreline morphodynamic evolution, and may be a valuable surrogate for more expensive physical hydraulic modeling.