People at the tidal flats: coastal morphology and hazards in Iqaluit, Nunavut

Hatcher, Scott (2014) People at the tidal flats: coastal morphology and hazards in Iqaluit, Nunavut. Masters thesis, Memorial University of Newfoundland.

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Abstract

Rapid environmental change observed in the Canadian Arctic is driving efforts at federal, territorial, and municipal levels to adapt to the impacts of projected changes. Recent work with communities has shown that targeted and relevant scientific input can greatly enhance ongoing vulnerability assessments and policy planning around adaptation and sustainability. The Arctic coast is dynamic, creating risk to Arctic coastal infrastructure. Using GIS modelling and geoscientific data collected over three field seasons, this thesis reports on a project aimed at providing coastal hazard mapping for Iqaluit, Nunavut. Iqaluit is the capital city of Nunavut, and sits alongside a macrotidal embayment with extensive tidal flats, which influence many aspects of life in the community. Data collected include: detailed topography and bathymetry, elevations of the coastal setting, elevations of past extreme water levels, and morphological mapping. The results build on previous work in Iqaluit, showing a relatively stable boulder-strewn sand flat morphology in the macrotidal embayment. Modelling of the coastal topography indicates a recent (last century) period of quasi stable sea level, with possible slight emergence persisting. Hydrodynamic data reveal little evidence for significant erosion through wave and current input. Recorded nearshore current velocities were between 0.1 - 0.3 m/s, with greater velocities at the top 3 m of the water column. The hazard mapping then attempts to incorporate the morphological mapping into a GIS of coastal infrastructure in the city in order to provide detailed information for city planners. Results show limited freeboard of 0.3-0.8 m for most coastal infrastructure under an upper-limit projection of 0.7 m relative sea-level rise from 2010 to 2100. Key infrastructure, and especially the subsistence infrastructure focused on the coast, is actually below past recorded maximum water levels during high spring tides. Lack of data, however, precludes any reasonable estimate of recurrence. Geomorphological mapping of the coastal setting provides crucial insight into the risks to infrastructure from storm waves, erosion, and sea-level rise. The study shows that the tidal flats are a source of coastal resilience in the form of wave dissipation, lowering ice pile-up/ride-up risk, and protection from rapid erosion.

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