An initial feasibility study on the use of Contrecoeur's dredged sediments as a cement additive was carried out. Analysis of the results revealed that Contrecoeur's harbour sediments are identified with reactive silty clays, which qualify as pozzolans according to ASTM C618 criteria. In this perspective of valorization of Contrecœur harbour sediments, the objective of this new study is to design a printable concrete with a low carbon footprint by partially incorporating 10% to 30% of the sediments. as demonstrated in Montreal Port Authority projects such as artificial reefs and tetrapods to protect the banks of islands and the St. Lawrence River against erosion. To this end, mortar incorporating dredged sediments will be manufactured for 3D printing. Sustainability and environmental issues will be assessed.

Approximately 80% of the population of Quebec (Canada) currently resides along the shores of the St. Lawrence and its tributaries. It has become increasingly evident that Quebec is losing land and is expected to lose more land in the coming decades due to changes in coastal and riparian dynamics resulting from climate change. Progressive shoreline erosion and submergence at storm events threaten the integrity of residential, industrial, port, and commercial infrastructure, as well as regional transportation infrastructure. In Quebec, the damage to roads and buildings represents potential costs of $1.5 billion by 2065 if no adaptation measures are implemented (2030 Plan for a Green Economy). Seawalls and ripraps are among two most popular protective measures utilized by the Ministère des Transports et de la Mobilité Durable du Québec (MTMD) of Government of Quebec; however, climate change was not adequately considered in the previous designs. Storm frequency will increase mainly because of decrease of sea-ice cover, which was strongly reducing wave climate in winter. Considerable engineering problems have been observed and will be expected to continue in near future, under the effects of climate change. MTMD is collaborating with the Université du Québec à Rimouski to establish the Coastal Engineering Research Chair program, aiming to enhance the response capabilities of government agencies to the rising coastal hazards. This program primarily focuses on three key areas: 1) Enhance the current understanding of coastal erosion and flooding, such as prediction of erosion rates; 2) Develop cost-effective adaptation solutions; and 3) Support local partners in validating and optimizing technical approaches and solutions. This presentation will introduce the Coastal Engineering Research Chair Program, highlighting the challenges, opportunities, and potential solutions to safeguard Quebec's coastal communities. Examples of recently constructed large-scale solutions implemented by the MTMD will be included as well.

Sea level rise and increase in storm frequency have motivated coastal asset managers to revisit the design of existing coastal structures to ensure that they are adapted to the changing climate. In particular, Dykeland Systems in Nova Scotia have been at the centre of these design revisions due to recent efforts to evaluate and upgrade the province’s Dykeland Systems for climate change. Design guidelines across Canada and around the world are providing design methods for flood protection structures such as dykes. However, these guidelines are often built to be conservative to reduce risks when designing engineered solutions. This prudent approach is most certainly the most advisable approach but it may result in overdesign, especially when waves, tides or storm surges have impressive scales. The case of Dykeland Systems around the Bay of Fundy, in Nova Scotia, is one such case where the scale of many coastal phenomenon is amplified due to the bay’s funnel shape. For instance, extreme tidal ranges, reaching 17 m, and amplified storm surge result in intertidal zones in the magnitude of kilometers of length, instead of meters. Designing coastal infrastructures is a great challenge in the area while balancing cost and risk. Dyke Design Guidelines from different region have different approaches and applying these to the Bay of Fundy’s Dykeland System results in very different dyke cross-section. The coastal conditions of the Bay of Fundy amplify the assumptions and statistical shortcuts taken in guidelines. The conclusions of this case study highlight the importance of engineering and scientific judgement in the design process, and the differences in results caused by statistical and deterministic approaches.