Increasingly, it is reported that the coastline of the Dakar region is affected by coastal flooding due to extreme water levels during wave events. Here, we quantify the extreme coastal water levels as well as the different factors contributing to coastal flooding during the period 1994–2015. Severe water levels reach values of 1.78 m and increase by 8.4 mm/year. The time spent above this threshold has already increased by 1.7 over the study period and will increase by 2100 to 8 times with 0.4 m mean sea level rise and up to 20 times with 0.8 m in the IPCC low and high greenhouse gas emission scenarios, respectively. Tide is the main contributor to the extremes when combined with large wave runup, due to wave breaking which contributes to 38% of the increase in extreme events while sea level rises to 44%. Our results show that because of its prominent location, Dakar region is affected by waves coming from the Northern and Southern Hemispheres with contrasted evolutions: wave runup events increase faster (7 mm/year) during austral winter due to a maximum of the South Atlantic storm activity, and have a decreasing trend (−3 mm/year) during boreal winter (December, January, February) driven by the evolution of corresponding climate modes.

Comme les autres cordons littoraux sableux du littoral acadien de la côte est du Nouveau-Brunswick (Canada oriental), la flèche de Bouctouche évolue actuellement dans le contexte d’une hausse du niveau marin relatif. Le trait de côte de la cellule sédimentaire de la flèche a été cartographié afin d’en déterminer le déplacement et d’établir le bilan sédimentaire pour la période pour laquelle une couverture photographique est disponible. Le long du Détroit de Northumberland, sa variation moyenne entre le Cap Richibouctou et l’extrémité nord de la flèche est de -0,14 ± 0,18 m/a. Cette valeur varie de -1,85 ± 0,2 m/a à +2,05 ± 0,2 m/a sur le front de la flèche, en recul sauf à son extrémité, alors que la limite externe du marais maritime occupant l’arrière de la flèche s’est maintenue dans l’ensemble (-8,63 ± 13 m). Les apports sédimentaires à la flèche sont insuffisants : elle présente un bilan fortement déficitaire et sa superficie a diminué depuis 1944. La cartographie des formes et dépôts de tempête suggère l’importance des fortes tempêtes dans l’évolution de la flèche. La localisation des brèches, dépôts de débordement et deltas de tempête dépend de la morphologie du trait de côte et de la flèche. À l’échelle temporelle considérée, la hausse du niveau marin relatif et les tempêtes ont causé 1) un recul du trait de côte du côté du détroit, sauf le long des trois derniers kilomètres de la flèche, où il y a surtout eu progradation, 2) une érosion du front dunaire et un haussement de la surface de l’arrière-dune adjacente, principalement dans la partie proximale de la flèche, grâce à la mise en place de dépôts de débordement, et 3) une migration transgressive de la flèche vers la baie de Bouctouche à de rares endroits.

Bourque, N. R., M.-A. Villard, M. J. Mazerolle, D. Amirault-Langlais, E. Tremblay, and S. Jolicoeur. 2015. Piping Plover response to coastal storms occurring during the nonbreeding season. Avian Conservation and Ecology 10(1): 12.http://dx.doi.org/10.5751/ACE-00734-100112

This study examines the hydrodynamic regimes in Shediac Bay, located in New Brunswick, Canada, with a focus on the breach in the Grande-Digue sand spit. The breach, which was developed in the mid-1980s, has raised concerns about its potential impacts on water renewal time and water quality in the inner bay. The aims of this study, using mathematical modeling approaches, were to evaluate the flow regimes passing through the breach and influences on the distribution of dissolved matter, providing insights into whether the breach should be allowed to naturally evolve or be artificially infilled to prevent contaminant stagnancy in the bay. The study considered three simulation scenarios to comprehend the water renewal time and the role of the breach in the environmental management of Shediac Bay. Results indicated that completely closing the breach would significantly increase the water renewal time in the inner bay, although the spatial extent of this increase is limited. However, the study identified some limitations, including the need to better define the concentration limit for considering water as renewed and the lack of consideration of dynamic factors such as wind and wave effects.