NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region

Tags: physical sciences, environmental impact, geology, climate change, coastal erosion, coastline

Objective(s): To obtain a better understanding of the geological conditions in the coastal zone and nearshore region in order to provide the government and stakeholders with the tools to ensure sound management of renewable and non-renewable resources in the western Canadian Arctic region.

Project Description: The Western Canadian Arctic is one of the most rapidly changing coastlines in the world and one of the most sensitive to climate change. The aim of the study is to obtain a better understanding of the geological conditions in the coastal zone and nearshore region in order to provide the government and stakeholders with the tools to ensure sound management of renewable and non-renewable resources in the region. Specific objectives of the study include: 1) observing and documenting coastal stability and related processes (wind, waves, sea ice, thaw processes, coastal erosion and sedimentation) at coastal monitoring sites throughout the region; 2) mapping coastal features, sediment properties and ice conditions in the shore zone (from the underwater shoreface to 10m water depth to the upper limit of coastal erosion or flooding) at sited through the region; 3) investigating surface morphology and potential geohazards in the outer Mackenzie Delta and the shallow seabed area to seaward; 4) studying processes and impacts of coastal flooding (from storm surges and spring freshet) in the Mackenzie Delta region; 5) monitoring vertical ground motion (subsidence and uplift) both regionally and locally with improved definition of vertical datum for better understanding of future sea-level and flooding impacts; 6) studying past rates of relative sea-level rise and estimating future rates and impacts in combination with other climate change effects in the region Field surveys will be undertaken in consultation with the Hunters and Trappers Committees in order to ensure the timing of surveys is compatible with local use of the land and water. Drilling and augering will take place in the winter and will employ hand tools or small truck-mounted geotechnical rigs (similar to shot-hole rigs used for seismic drilling) which do not use drilling fluids. Monuments for GPS surveys will involve jet drilling (summer or winter) to depths of 10-30 m in order to install steel pipe or wooden monuments, generally at sites where previous research, monitoring, or exploration activity has taken place. The monuments will be visible above the ground surface (approximately 1 m) and will have a mounting bracket attached to them. Radar reflectors may be deployed at these locations for periods of months to years in order to help validate remotely sensed data and investigate land subsidence. The radar reflectors are 1 m triangles made of a metal mesh. Spring break-up and summer camps will be small (2-4 people) and of short duration (less than 10 days) and will be supported by helicopter. Winter (March-April) camps will involve up to 8 people and last for up to 2 weeks. Efforts will be made to use industry camps or to co-locate camps with oil industry activities in order make use of their roads and other infrastructure and minimize footprints and potential disturbance. Acoustic surveys will be undertaken in the summer and fall open-water season during the month of August (after whaling season). Most will use very low-energy echosounders. Small boats up to 8 m in length will be the primary means of data collection; however, if funding permits, the researchers may use the CCGS Nahidik or a similar vessel as a mothership to support nearshore small boat activities. All instrumentation deployed on the seabed will remain stationary and record changes using non-invasive and passive measurements for periods lasting several days or several months. Each logger is battery-operated and no greater then 12 cm in diameter and housed within stainless steel 1-2 m mounting frames. Loggers will be deployed in locations and at depths to pose no hazard to shipping or boat traffic. A buoy will be placed at each location while it is on the seabed. Temperature measurements in boreholes will be made by installing 2 inch plastic casing into a jet-drilled hole and threading a series of up to 10 thermistors on an electrical cable into the borehole. A data logger will be installed to capture temperature readings several times per day at each depth in the borehole. Ground penetrating radar surveys will be undertaken in the winter from the ice surface using sleds pulled by human or snowmobile power. If funding permits, the snow off the ice surface may be ploughed using an ATV prior to GPR surveys. Research activities will be carried out from March 15 to April 15, May 14 to June 10, and August 1-31, 2007 at sites on the Mackenzie Delta and mainland coast, Banks Island, Victoria Island, Prince Patrick Island and Melville Island.