David Didier

Université du Québec à Rimouski UQAR | uqar · Département de Biologie, Chimie et Géographie

Projet de doctorat

Widely spread worldwide, beach-ridge systems are established along prograding coastlines, either fostered by a falling Relative Sea-Level (RSL), by substantial sediment stocks being provided to the coastline, or by the combination of both agents. As such, they can form valuable archives of either large scale RSL and isostatic dynamics and/or of mor...

Cliff-top boulder deposits (CBDs) are morphological indicators of high-energy conditions. Since 2014, a monitoring of CBDs dynamics has been undertaken on the south-western coast of Iceland (Reykjanes Peninsula) to monitor their long-term activation (quarrying, transport and deposition) as a proxy of the inter-annual winter storminess variations an...

Deltas are at the transition between fluvial and marine sedimentary environments where sediment density flows are often triggered during high river discharge events, forming submarine channels and sediment waves. On wave‐influenced deltas, longshore currents are particularly efficient at transporting sediment alongshore, reducing the likelihood of...

An improved understanding of the resilience capacity of salt-marsh environments, which are recognized as one of the most vulnerable yet valuable coastal morpho-sedimentary systems is important for enhancing resilience to future sea-level rise. The aim of this study is to provide a long-term (multi-centennial) context to the capacity of response of...

La région Arctique est particulièrement fragilisée par les changements climatiques, où le réchauffement est deux à trois fois plus élevées qu’ailleurs sur la planète. On note une diminution massive de l’étendue et de l’épaisseur de la glace de mer, ce qui prolonge la période d’eau libre de glace et qui expose les côtes aux évènements de tempêtes pr...

Impacts from a changing climate, in particular sea-level rise, will be most acutely felt on small oceanic islands. A common configuration of mid-latitude islands is the sandy barrier island. Sable Island, Nova Scotia, Canada is a vegetated sand island near the shelf edge, 160 km from the nearest point of land, that is morphologically similar to a b...

Knowledge of empirical equations relating offshore wave conditions and nearshore dynamics are essential in coastal engineering and coastal risk assessments. Swash, which is the high-frequency component of coastal water levels, has been extensively studied on ‘warm’ beaches (i.e. not affected by cryogenic processes). Several formulations have been s...

Contrasting coastal environments are present along Canada’s northern coastline, making adaptation strategies highly site-speciEc. To better understand the response of Arctic and Subarctic coasts to increasing environmental pressure, shoreline changes in the 14 communities of Nunavik (northern Quebec, Canada) were investigated. Shoreline positions w...

Conférence Ocean Science Meeting San Diego 2020

Empirical models of wave runup are commonly derived from open beaches, but their applicability in fetch-limited, sheltered environments are yet to be properly assessed. Based on original video-derived runup observations on 5 beaches with distinct morphodynamic states in the Estuary and Gulf of St. Lawrence (EGSL), this paper presents a runup analys...

Along the Estuary and Gulf of St. Lawrence (EGSL), nearshore ice complex (NIC) influences coastal dynamics, especially on sandy coasts where it causes erosion, transport and sediment accumulation. NIC morphology evolves under various wave, tide and meteorological conditions. Impacts of climate change such as increasing winter temperature and freeze...

Coastal management often relies on large-scale flood mapping to produce sea level rise assessments where the storm-related surge is considered as the most important hazard. Nearshore dynamics and overland flow are also key parameters in coastal flood mapping, but increase the model complexity. Avoiding flood propagation processes using a static flo...

Coastlines along the St. Lawrence Estuary and Gulf, Eastern Canada, are under increasing risk of flooding due to sea level rise and sea ice shrinking. Efficient and validated regional‐scale coastal flood mapping approaches that include storm surges and waves are hence required to better prepare for the increased hazard. This paper compares and vali...

Coastal hazards in Eastern Canada are mainly associated to storm conditions: storm surge and high waves generate coastline erosion and flooding. There is a critical need to develop effective tools for coastal management as sea ice reduction and sea level rise will likely impact future coastal hazards. In recent years, a simple and operational metho...

While recent studies highlighted the great mobility of boulder beaches related to the impact of storm waves, numerous researches are still needed to better understand the morphodynamic of coastal boulder accumulations. This paper provides original data about storm-induced geomorphic processes and their impact on the Valahnúkur coastal barrier. Firs...

Une méthodologie simple et opérationnelle permettant d’évaluer le niveau de risque associé à l’érosion et à la submersion côtière a été développée en collaboration avec le ministère de la Sécurité publique du Québec. Le développement s’est effectué sur un secteur de la MRC de La Mitis qui connait déjà des problématiques liées aux aléas côtiers (30...

Increasingly used shore-based video stations enable a high spatiotemporal frequency analysis of shoreline migration. Shoreline detection techniques combined with hydrodynamic conditions enable the creation of digital elevation models (DEMs). However, shoreline elevations are often estimated based on nearshore process empirical equations leading to...

Cette synthèse les positionne dans le contexte d’une gestion de risque, synthétise les facteurs qui contraignent son fonctionnement et souligne des critères de réussite.

Depuis les « grandes marées » de 2010, le Saint-Laurent est très médiatisé : des tempêtes à répétition ont causé des dommages sur les côtes, et plusieurs résidences ont été submergées. Théoriquement, la submersion de 2010 avait une récurrence très faible, supérieure à 100 ans. Or, à la veille de l’année 2017, des submersions extrêmes ont massivemen...

Early warning systems (EWS) are methods implemented in natural risk management. For many decades, they have been applied to all kinds of hazards, especially water-related and geological ones, but are rarely effective. In the last few decades, the Province of Quebec was hit by many water-related hazards (ice storms, inland and coastal flooding, coas...

Wave runup in a shore platform environment has been acquired by in situ measurements at high tide and along field debris following the December 6, 2010, flood near Rimouski (Quebec, Canada), south coast of the St. Lawrence estuary. Using offshore wave data and beach slopes, a linear empirical runup relationship has been adjusted to the study site a...

Au Québec, aucun zonage de la submersion n’existe. Les rives du Saint-Laurent sont gérées comme celles des autres cours d’eau. L'effet des vagues et de la géomorphologie littorale sont donc omis, sous-estimant l’aléa. Pour intégrer ces composantes, deux études ont été réalisées suite à la tempête du 6 décembre 2010, à Sainte-Luce (Bas-Saint-Laurent...

On 6 December 2010, an extra-tropical storm reached Atlantic Canada, causing coastal flooding due to high water levels being driven toward the north shore of Chaleur Bay. The extent of flooding was identified in the field along the coastline at Maria using DGPS. Using the assumption that the maximum elevation of flooded areas represents the combina...

La méthode classique de cartographie de la submersion consiste en une analyse des récurrences de surcotes sur une série temporelle de niveaux marégraphiques. Cette méthode ne considère pas l'effet des vagues et de la géomorphologie, ce qui peut entraîner une sous-estimation des zones à risque de submersion. Afin de mieux comprendre l’effet de ces c...

Dans le cadre du projet Évaluation économique des répercussions des changements climatiques et analyses coûts-avantages d’options d’adaptation aux changements climatiques en zone côtière au Québec, une évaluation de certains secteurs sensibles à la submersion doit être réalisée. Dans ce travail, une partie du territoire de la municipalité de Maria...

Le 6 décembre 2010, une dépression engendrait la submersion du littoral de l’estuaire et du golfe du Saint-Laurent. Il s’agissait de la conjoncture d’une pleine mer supérieure de vive eau, d’une surcote, et du wave runup, soit l’amplitude entre la limite supérieure du jet de rive et le niveau de la mer sans agitation. Après la tempête, les limites...

Synthetic aperture radar (SAR) data from RADARSAT-2 allows monitoring of sea ice in operational setting. To complete its mission, the Canadian Ice Service needs parameters such as ice-edge location, stage of development and ice concentration. Due to contrast variations driven by sea state and winds, such parameters can be difficult to define. In Fe...

Ice canoe was once a transportation mean during winter in Quebec to cross the St. Lawrence river. We used it as research tool in hardly accessible sea ice condition.