Dominique St-Hilaire
Coordinates
Office: SN 2005
Telephone: (709) 864- 6127
Fax: (709) 864- 3119
E-mail: dominique.sthilaire@hotmail.com
Supervisor
Dr. Trevor Bell, Dr. Donald Forbes, Dr. Arthur Dyke and Dr. Bob Taylor
Thesis title
Arctic coastal dynamics under changing relative sea-level and environmental forcing, Canadian Arctic Archipelago.
Research description
The primary goal of my doctoral research is to define Arctic
gravel beaches sensitivity and response to changing environmental
forcing in the context of anticipated climate change. Two
environmental variables that will have a significant impact on the
Arctic coastline are relative sea-level (RSL) rise and reduced
sea-ice cover (ACIA, 2005). Both can alter the wave energy regime
at the coast, causing flooding, enhanced erosion and shoreline
retreat, and influencing the morphology and sedimentology of
depositional landforms. Such changes represent increased hazard
risk for community infrastructure, nearshore benthic habitats, and
coastal resources. Projecting the future response of the coastal
system to these changes in forcing is a prerequisite for an
effective adaptation strategy (Ford et al., 2006).
Two complementary approaches are used in order to achieve this
goal: (1) the study of past responses under time-varying conditions
as recorded in the geological record and (2) the study of present
responses under spatially varying forcing as interpreted from
modern processes. Study sites are selected along a longitudinal
transect in the Eastern Arctic encompassing gradients of both RSL
trends (Tarasov & Peltier, 2004) and coastal exposure and
sensitivity to different levels of energy. The westernmost sites
are expected to show characteristics of regressive coastal systems
in response to postglacial relative sea-level fall (Dyke and
Peltier, 2000). Sequences of raised marine landforms encompassing
the last few decades to millennia will form the basis of the
geological record needed to help understand the dynamics of the
past and present coastal system. Evidence of transgressive systems
is expected at the easternmost sites where the postglacial RSL
lowstand and past shorelines are submerged below present sea level
(Andrews, 1989). Candidate sites from west to east are: Lowther
Island, Griffith Island, Resolute area, Cape Charles Yorke, Lavoie
Point, Bylot Island and Pond Inlet and vicinity.
Onshore research is conducted using the following methods:
multi-temporal analysis and mapping of modern and relict (raised)
coastal systems using airphotos, satellite imagery, LiDAR and RTK
surveys. Land-based work supports temporal studies on the modern
coastline using both historical records and ongoing monitoring
programs. Surveys of raised marine landforms build on my MSc
research and lead to a better understanding of the dynamics of
regressive coastal systems (St. Hilaire et al., 2006).
Shallow-water mapping of transgressive coastal systems will be
carried out using multibeam sonar, single-beam and side-scan
echo-sounders, sub-bottom profiler and sediment cores, primarily
from the CCGS Amundsen and the CSL Heron during ArcticNet NCE
scientific cruises, but local small boat charter and/or ice
platforms may also be utilized. Sea-floor imagery and sub-bottom
profiles will enable a better understanding of past coastal
response to rising RSL and how the offshore topography and sediment
composition influence the development of coastal systems under both
rising and falling RSL.
The project is consistent with the objectives of Projects 1.2 and 2.4 of the ArcticNet NCE and will form part of a larger integrated regional impact study (IRIS) of climate change in the eastern Arctic. It also contributes to an improved understanding of coastal hazards and climate-change impacts in the coastal zone and will inform decision-making for community and government adaptation strategies to climate change.
