Pascal Bernatchez

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

Decision-making in a coastal socio-ecological system involves managing a site-specific complexity arising not only from the interaction between hydrodynamic and morphological conditions, but also from the interactions between human structures and ecological systems, as well as the conflicting needs and interests of local actors. In addition, the pr...

Combinaison of optic and acoustic remote sensing to retrieve benthic reflectance for shallow water ecosystem cartography

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...

High-resolution LiDAR images reveal new landforms of glacial erosion that strongly nuance previously published interpretations about the glacial history of Anticosti Island. Carved into bedrock, these forms of glacial erosion are very diverse: glacial overdeepening lakes, rock drumlins, giant grooves, mega crag-and-tail, slabs of rock displaced by...

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...

In the context of climate change, the coasts of the Estuary and Gulf of St. Lawrence are expected to be more exposed to coastal erosion, where the population of Eastern Quebec and many stakes are concentrated. A methodology was developed and applied to 8 study sites, totalling 171 km of coastline, to determine the level of vulnerability to coastal...

Intertidal vegetation provides important ecological functions, such as food and shelter for wildlife and ecological services with increased coastline protection from erosion. In cold temperate and subarctic environments, the short growing season has a significant impact on the phenological response of the different vegetation types, which must be c...

Coastal socio-ecological systems are complex adaptive systems with nonlinear changing properties and multi-scale dynamics. They are influenced by unpredictable coastal hazards accentuated by the effects of climate change, and they can quickly be altered if critical thresholds are crossed. Additional pressures come from coastal activities and develo...

The decision-making process of the coastal defence measures (CDMs) is complex and filled with uncertainties due to site-specific interactions between hydrodynamic and geomorphological conditions, which have repercussions on the ecological and social aspects of coastal communities. Scientific knowledge of the effects of CDMs contributes to the reduc...

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...

As land use intensifies, many coastal waters are becoming enriched with otherwise limiting nutrients, leading to eutrophication. While the extreme effects of eutrophication on benthic communities are well documented, there is still a lack of knowledge about how nutrient enrichment alters biogeochemical interactions occurring at the sediment-water i...

This article focuses on the quantification of retreat rates, geomorphological processes, and hydroclimatic and environmental drivers responsible for the erosion of an unconsolidated fine-sediment cliff along the north shore of the Gulf of St. Lawrence (Quebec, Canada). Annual monitoring using field markers over a period of twenty years, coupled wit...

Coastal ecosystems are recognized as important providers of ecosystem services such as carbon storage, increased fish productivity, and wave energy reduction. In a context of climate change, coastal ecosystems are exposed to erosion and subject to coastal squeeze, even as they provide natural coastal protection against extreme weather. While civil...

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...

Shoreline armoring has repercussions on coastal processes, including reducing the width and height of sandy beaches, which affect coastal ecosystems and ecosystem services. This project, consisting of two parts, was carried out in the Canadian province of Quebec, on the coasts of the St. Lawrence Estuary and Gulf, which cover the territory of 21 co...

Sea ice plays an important role in subpolar seagrass meadows. It protects meadows against wave action and extreme temperatures. On the other hand, sea ice destroys seagrass leaves and removes plots of sediments and organics debris, leaving long-lasting ice-made tidal pools of various shapes and sizes within the meadow. The present study aimed at in...

The St. Lawrence is a vast and complex socio-ecological system providing a wealth of services that sustain numerous economic sectors. This ecosystem is subject to significant human pressures that overlap and potentially interact with climate-driven environmental changes. Our objective in this paper was to systematically characterize the distributio...

Poster de projet de thèse présenté lors de la RSA 2020 de Québec Océan

Conférence Ocean Science Meeting San Diego 2020

The landscape and landforms of the Magdalen Islands are uniquely varied for such a small archipelago. Geomorphologically they are a part of the Maritime Plain which is located near the center of the Maritime Basin (375–325 Ma). The Magdalen Islands were pushed to the surface by salt-diapirs (~300 Ma). Formed by volcanic hills (basalt) surrounded by...

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...

As part of a collaborative study with the Ministry of Transport of Québec, a Coastal Road Erosion and Flooding Vulnerability Index (CREFVI) was developed for the short (2020), medium (2060) and long term (2100). Nine study sites in Eastern Québec (Canada) were used to develop the index, for a total of 122.4 km of roads. The index includes 14 parame...

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...

L’augmentation du développement en zone côtière combinés aux effets des changements climatiques ont mené à une augmentation de l’artificialité du trait de côte. Aujourd’hui, il est estimé que 50% des côtes à l’échelle mondiale sont menacées par l’aménagement de structures de protection, de secteurs portuaires ou d’autres infrastructures visant à su...

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...

Late Holocene sea-level changes can be reconstructed from salt-marsh sediments with decimetre-scale precision and decadal-scale resolution. These records of relative sea-level changes comprise the net sea-level contributions from mechanisms that act across local, regional and global scales. Recent efforts help to constrain the relative significance...

A regional assessment of cumulative impacts is required for the Estuary and Gulf of St. Lawrence to facilitate ecosystem based management supported by evidence. The only currently available assessment was performed at the global scale using 19 drivers of anthropogenic stressors such as fisheries and pollution. While valuable, certain datasets inclu...

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...

The late Pleistocene–early Holocene transition period was characterized by rapid environmental change. Here, we investigate the impact of these changes on the marine invertebrates living in a shallow inlet of the post-glacial Goldthwait Sea. The site is located near Baie-Comeau (QC, Canada), where a number of remarkably well-preserved shell deposit...

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...

Le projet de recherche Résilience côtière a été initié en janvier 2017, en partenariat avec les municipalités et MRC côtières de l’Est du Québec, afin de développer des outils et des solutions d’adaptation aux aléas côtiers pour réduire la vulnérabilité des communautés et des écosystèmes. Une tâche très importante d’acquisition de connaissance est...

Coastal evolution is complex, in particular with the migration of the shoreline and the successive appearance of erosion or accumulation zones. Quantitative monitoring of coastal systems is widely used to understand their temporal and spatial evolution. Several topographic survey methods have been used (RTK-GNSS, airborne LiDAR and terrestrial stat...

Gathering data for large scale, systematic research initiatives such as regional multi-stressor analyses can be a very challenging - not to say painful - process. On one hand, there is an overwhelming wealth of data available, while on the other hand, some required data remain largely unavailable or inaccessible. Coupled with political intricacies,...

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...

The Magdalen Islands (Québec, Canada) in the centre of the Gulf of St. Lawrence are located in a strategic position for providing an overview of the relative sea-level (RSL) history of the Maritime Provinces of eastern Canada. Although data are available for the coastal terrestrial areas of the Maritimes, data from the Gulf are very scarce and both...

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...

This study presents the development of a geographic information system (GIS) land-use planning tool for coastal areas based on the calculated exposure to coastal erosion of buildings and infrastructure. Responding to the needs of land-use planners, who are involved in the project from the beginning, this tool facilitates identification of adaptatio...

Proxy records of late Holocene relative sea-level changes are important for our understanding of mechanisms that drive contemporary sea-level trends. In the Gulf of Saint Lawrence (eastern Canada), the Magdalen Islands currently experience higher than global average rates of relative sea-level rise. This article presents original reconstruction dat...

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...

The Magdalen Islands (Québec, Canada) are a key location for unravelling the glacial and sea-level history of the Maritime Provinces of eastern Canada. Although many sedimentary sequences have been described in the literature, absolute ages are lacking, impeding an accurate interpretation of the deposits and the establishment of a precise chronolog...

Les écosystèmes côtiers s’ajustent à la hausse du niveau de la mer en migrant vers les terres. Or, dans les zones sujettes à une accélération de la montée du niveau de la mer et à un déficit sédimentaire, des contraintes naturelles (p. ex. falaises) ou artificielles (p. ex. routes, structures de protection) présentes sur la côte, peuvent freiner ce...

Sediment transport in the salt marsh and the lagoon of Penouille is driven by tidal currents, waves, wind, and ice rafting, which interact with topography and vegetation to control the spatial distribution of surface sediments. Multiple linear regressions of 203 samples of marsh surface sediments show that grain size gets finer and organic matter c...

Les glaces côtières jouent d’importants rôles dans la morphodynamique littorale et leur absence augmente l’exposition de la plage face aux conditions météo-marines hivernales. Les études sur les effets des processus glaciels sur la morphologie des plages sont essentiellement basées sur des observations qualitatives. L’objectif de cette étude est de...

Vulnerability to coastal hazard is a concept prescribed by UNISDR, IPCC and governments. (IPCC CZCS, 1992; UNISDR et al., 2010; ADEME, 2013; MDDELCC, 2015). However the challenge is methodological : a ”just” use of vulnerability assessment with erosion would include predictive model and only inductive arguments (Hinkel, 2013). Also, previous coasta...

Especially in the Estuary and Gulf of St. Lawrence, where impacts from accelerated coastal erosion and anticipated sea level rise are significant, the design of community-scale indiactors for adaptation tracking needs to be rooted in the local contexts. Building over a transformational adaptation framework at the scale of communities, this research...

Vulnerability to coastal hazard is a concept prescribed by UNISDR, IPCC and governments. (IPCC CZCS, 1992; UNISDR et al., 2010; ADEME, 2013; MDDELCC, 2015). However the challenge is methodological : a ”just” use of vulnerability assessment with erosion would include predictive model and only inductive arguments (Hinkel, 2013). Also, previous coasta...

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...

This paper investigates the processes involved in unconsolidated cliff recession using LiDAR surveys (2005, 2010 and 2013) and aerial photographs (1964-2012) at Pointe-au-Bouleau, on the north shore of the St. Lawrence estuary, in eastern Canada. The high lithostratigraphic variability of the sediments allowed for the identification of stratigraphi...

This spreadsheet (Excel) contains the legend of the semi-quantitative coastal classification. It is a part of an appendix that accompanies a manuscript in my thesis. ABSTRACT: As the sea-level is rising, a better consideration of coastal erosion into integrated, systemic and community-based approach to coastal vulnerability assessment is vital for...

Ce guide a été conçu pour les personnes et les organismes qui ont besoin d’utiliser les données du Réseau de suivi des infrastructures vulnérables à l’érosion côtière du Québec maritime du Laboratoire de dynamique et de gestion intégrée des zones côtières de l’UQAR. Que vous soyez un représentant d’une municipalité, une réserve autochtone, un minis...

Ce guide a été conçu pour les personnes et organismes qui ont besoin d’utiliser les données du Réseau de suivi de l’érosion côtière du Québec maritime du Laboratoire de dynamique et de gestion intégrée des zones côtières de l’UQAR. Que vous soyez un représentant d’une municipalité, d’une réserve autochtone, d’un ministère, d’une entreprise privée o...

Ce document est une annexe détaillée des indicateurs qui accompagnent le chapitre intitulé "Analyse institutionnelle de la trajectoire d’adaptation aux changements climatiques dans le Québec maritime" RÉSUMÉ DU CHAPITRE: Les impacts des changements climatiques (CC) sur les zones côtières constituent une source de préoccupation qui ne cesse de progr...

Les impacts des changements climatiques (CC) sur les zones côtières constituent une source de préoccupation qui ne cesse de progresser dans l’ordre des priorités du gouvernement du Québec. Au cours des deux dernières décennies, cet intérêt a été accompagné par la multiplication des efforts d’adaptation, comme encore récemment la mobilisation de fon...

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...

Un Indice de Vulnérabilité des Routes aux Aléas Côtiers (IVRAC) a été élaboré pour le court (2020), le moyen (2060) et le long terme (2100). Le développement s’est effectué sur neuf sites témoins situés dans l’Est-du-Québec (soit 122,4 km de routes) dans le cadre d’une étude menée en collaboration avec le ministère des Transports du Québec. Cet ind...

D’origine naturelle et anthropique, les impacts de l’érosion côtière sont irréversibles à plusieurs endroits sensibles dans l’estuaire et le golfe du Saint-Laurent. En s’appuyant sur le cadre conceptuel de l’adaptation transformationnelle à l’échelle des communautés, et considérant le manque chronique de ressources, les objectifs de cette recherche...

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...

The Magdalen Islands are a valuable terrestrial record, evidencing the complex glacial and periglacial history of the Gulf of St. Lawrence. Thirteen structures interpreted as ice-wedge pseudomorphs or composite-wedge casts were observed at four sites on the southern Magdalen Islands and testify to the former presence of permafrost under periglacial...

Cette étude constitue la première évaluation économique de l’impact potentiel de l’érosion côtière sur les infrastructures du Québec maritime dans un contexte de changements climatiques, si aucune nouvelle mesure d’adaptation n’est mise en place et que celles déjà en place ne sont pas entretenues. Tous les bâtiments, les routes et les chemins de fe...

Vulnérabilité des infrastructures routières de l'Est du Québec à l'érosion et à la submersion côtière dans un contexte de changements climatiques : Volume 3 Développement d'une approche et d'un indice pour quantifier la vulnérabilité des infrastructures routières à l'érosion et à la submersion côtière dans un contexte de changements climatiques sur...