GEOL 5903 Seminar - Brian Laureijs
4 December 2020
GEOL 5903 Seminar: Brian Laureijs
Title: Reinforcement or Restoration? Examining flood risk mitigation options on the Fundy Dykelands
Time: 2:30 p.m. - 3:30 p.m.
Presentations via TEAMS
Abstract:
The Bay of Fundy dykelands in Nova Scotia and New Brunswick are economically and culturally valuable infrastructure that face an uncertain future. The combined interactions of post-glacial crustal subsidence, climate change influenced sea level rise, and changes in tidal resonance will result in both higher relative sea levels and increases in the Bay’s tidal range. Coincidence of storm surge and spring tides have historically resulted in devastating flooding. Geomatics technologies have shown promise in improving our ability to model future breaching and realigning of dykes in an effort to determine where dykes can be retained and where tidal salt marsh should be restored, and additionally, have shown evidence of the efficacy of marsh restoration. Foreshore marsh vegetation alters hydrology and slows water velocity while also absorbing wave energy, creating a natural protection against flooding. In locations with sufficient sediment deposition rates, marsh growth has been shown to keep pace with relative sea level rise. In areas of the Upper Bay where suspended sediment and soil accumulation is high, salt marshes also contribute to carbon sequestration. Yet the decision to restore marshes over maintaining existing infrastructure bears controversy. Maintenance of the status quo through dyke reinforcement and upgrades to aboiteaux and drainage infrastructure are favoured by local stakeholders. Management authorities, however, recognize that simply “topping the dykes” is no longer sustainable, and lack resources to improve all dyke infrastructure to projected sea level rise. Assessment of local context and impact forecasting are important to building a resilient management plan for the future of our dykelands. These methods used to improve resiliency are a matter of ongoing discussion, and are important to the determination of a balance between preservation of cultural significance and preparing for the future.