Causes and Adaptation Strategies to Shoreline Erosion in Sept-Îles
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Coastal communities adjacent to the Gulf of St. Lawrence are witnessing high rates of shoreline erosion, up to eight meters per year. To assess the causes and develop adaptation solutions to accelerated erosion, the provincial government asked Ouranos, a regional climate consortium, to study historical and current rates and causes of erosion. The study was conducted in the Gulf of St. Lawrence, mostly within the municipalities of Sept-Îles, the Magdalen Islands, and Percé. They concluded that reduced wintertime sea ice, heavy precipitation, and changes in storm intensity are exacerbating erosion rates. In the meantime, Sept-Îles has implemented temporary legislation to reduce the community’s vulnerability to climate change.
Sept-Îles is one of the northern most towns in Quebec, Canada with any significant population. It is located adjacent to the Gulf of St. Lawrence, sandwiched between the Sainte-Marguerite and Moisie rivers. Its shoreline is comprised of unconsolidated sediments making it very vulnerable to erosion; in some areas, recent land losses have been up to eight meters per year. Earlier attempts to protect shorelines (such as rock protections) have exacerbated erosion rates in adjacent sections. Thus, Sept-Îles wanted to investigate new protective measures to reduce erosional rates.
To evaluate the vulnerability of coastal populations to erosion, multiple provincial Ministries agreed in 2000 to support a research project to analyze the current and historical rates of shoreline erosion and develop integrated management solutions for the region. From 2000-04, scientists used aerial photographs to infer historical erosion rates relative to current rates. Results indicated that current erosion rates measured over the past decade far exceed historical norms. The scientists hypothesized that the increased erosion rates could be due to sea level rise, reduced and shorter periods of sea ice extent, and increased storm intensity.
Ouranos, a regional climate consortium, was asked to assess different adaptation measures and to study the complex coastal dynamics that are causing a higher rate of erosion. They found that the frequency of rain, winter thaws, and heavy precipitation have accelerated erosion rates on beach bluffs and that reduced winter sea ice has exposed beaches and shorelines to more intense, winter-time wave action.
Outcomes and Conclusions
In addition to Ouranos' assessment, Sept-Îles undertook three main initiatives to enhance the community’s resilience to climate change:
- Held public education sessions to inform the population of current and future risks;
- Used erosion maps to identify “areas at risk” for a 25-year time horizon and in high risk areas, enacted temporary development guidelines and restrictions; and
- Created a technical committee to develop a master plan for coastline intervention in order to proactively deal with erosion and coastal management problems over the near and long term.
Feifel, K. (2010). Causes and Adaptation Strategies to Shoreline Erosion in Sept-Îles [Case study on a project of Ouranos]. Product of EcoAdapt's State of Adaptation Program. Retrieved from CAKE: http://www.cakex.org/case-studies/causes-and-adaptation-strategies-shore...îles (Last updated March 2010)