NWT RESEARCH DATABASE

Regions: Dehcho Region

Tags: physical sciences, petroleum industry, hydrology, industrial development, pipeline corridor, topography, biophysics

Objective(s): To conduct biophysical and reconnaissance studies in the Inuvialuit Settlement Region, including route and site reconnaissance, aquatic, terrestrial, engineering, geological and geophysical studies.

Project Description: Several biophysical and engineering studies on the feasibility of a pipeline in the Mackenzie Valley have been conducted, and will continue in 2007. Local knowledge, scientific research, and existing technical information are being used to develop a knowledge base for environmental protection plans, engineering design and regulatory processes. Route and site reconnaissance will be carried out by helicopter, and will include ground observation. Landings will occur at selected sites, subject to avoiding sensitive areas and confirmation by the local community representative. Reconnaissance surveys of water courses crossed by temporary and permanent access roads will also be performed. Aquatic studies will be conducted by three or four-person crews, primarily by helicopter. Crews will collect fish, fish habitat, hydrology, and water quality data and samples. These investigations will also be carried out at proposed barge landing sites. Winter fish and fish habitat surveys may be conducted during late winder at select streams with running water under the ice. For streams with ice cover, holes will be augured through the ice to determine ice thickness and water depth below the ice. Under-ice, in situ water quality parameters such as temperature, dissolved oxygen, conductivity and pH will be measured. Additionally, there is a potential that fish habitat in water bodies immediately adjacent to proposed borrow sites might be studied. River channel and thalweg surveys will be carried out by boat around each crossing point. Depth measurements will be taken with echo sounders (depth finders) for larger rivers and with survey rods for smaller streams. Spring breakup observations will occur to gather information during the later winter and spring breakup periods that will assist in the engineering design of watercourse crossings. Instrumentation, such as time lapse and video cameras, might be temporarily installed to monitor the breakup cycle. Terrestrial studies will be conducted by helicopter. A local assistant will assist the survey team in observing and recording data taken at survey sites, and inform the study team of sensitive or important areas, and if necessary, searching for and recording occurrences of rare plants and helping to identify plants of cultural or traditional importance. Mapping of vegetation required at potential infrastructure sites, roads, borrow sites, the anchor field and at select locations along the pipeline will be conducted where further information is still required. Soil sampling might be conducted at select sites withint the proposed study area (typically where rare plant surveys are conducted). At such sites, a soil pit ~15cm x15cm will be excavated with a spade or auger to a depth of about 0.5 m or to the top of the permafrost. The exposed soil profile will be documented. Following assessment, the soil pit will be backfilled with the excavated material and the sod replaced. Thermistor data recovery is planned with the installation and re-installation of thermistor strings and data loggers in previously prepared sites. Data will be downloaded from previously installed thermistor data loggers and collected from manually-read thermistor sites. Engineering studies will also entail airborne and surface reconnaissance of key side and longitudinal slopes along the proposed pipeline route that are identified from aerial photography and LiDAR data. The slopes will be assessed from thermal and stability design and regulatory compliance perspectives. Ground-based and airborne geophysical surveys will be undertaken to evaluate the suitability of various geophysical surveying techniques for use in mapping ground and subsurface geologic features and conditions. The study boundaries include the proposed pipeline corridor, infrastructure sites, access roads to planned facilities and other areas such as waterbodies, borrow sites and alternative pipeline corridors. The biophysical and reconnaissance studies will be carried out from March 16 to December 29, 2007.