Base de données de recherche des TNO

Régions: Inuvialuit Settlement Region

étiquettes: physical sciences, petroleum industry, ecosystem changes, environmental impact assessment, mapping, seabed

Objectif(s): This project is designed to evaluate new technologies that could prove effective in assessing the environmental impact of offshore pipelines on the renewable resources of the Beaufort Sea. A knowledge of the deepest ice scours cutting into the seabed will constrain engineering design and minimize the potential of pipeline failure by ice keel impact. A knowledge of the location and sensitivity of unique seabed habitats related to the renewable resources of the Beaufort Sea is required to provide a basis for assessing the ecosystem impact of proposed offshore pipeline routes - and the selection of a route which is environmentally friendly. This project has 2 objectives: (1) multibeam sonar technology will be tested to determine how effectively it maps the distribution and depth of seabed ice scours caused by sea-ice pressure ridge keels; and (2) multibeam sonar and deep towed camera system technologies will be tested to determine how effectively they map the character of the seabed - in particular the nature of seabed habitat. If these new technologies prove effective the future plan is to conduct a multi-year program beyond 2001 (2002 to 2005) to map the distribution of extremely deep ice scours and sensitive habitats on the Beaufort Shelf.

Description du projet: The Coast Guard vessel CCGS Nahidik will be used as a research platform to conduct offshore surveys in the Beaufort Sea. A regional grid of survey lines which were first surveyed in the1980's will be resurveyed as follows: (1) using a 300kHz short range multibeam echo sounder (Simrad EM 3000) to produce along-track maps of the topography and character of the seabed. These tracks will be approximately 200m wide on the seabed; (2) using a 100 kHz sidescan sonar (Klein 595) to map the distribution of ice scours on the seabed for comparison to historic data and to calibrate the multibeam data; (3) using a single beam 200 kHz echo sounder to map the depths of ice scours on the seabed and to calibrate the multibeam sonar; (4) using a bottom towed video camera system to photograph the nature of the seabed and benthic habitat; and (5) collecting sediment grab samples of the upper 20cm of seabed to provide sample control to calibrate the multibeam sonar and video camera data. It is anticipated that about 36 seabed samples will be recovered for grain size analysis. The field program survey activities onboard the CCGS Nahidik are planned for July 31 to August 19, 2001. If the evaluation of new technology proves successful then future surveys are planned for 4 additional years in the same area in August using the same technologies. Data collected in future years will be used to identify new ice scours which occurred since 2001 and to map the distribution and nature of offshore benthic habitats. The 2001 data will provide the baseline information for the future research. In addition future work beyond 2001 may well focus in specific areas across the shelf.