NWT RESEARCH DATABASE

Tags: environmental assessment, biology, habitat assessment, industrial development, wetlands, aquatic biology

Objective(s): This is a three part study with separate objectives for each. The objectives are as follows: 1) The Fish Study: Evaluate the impacts associated with four locations requiring in-stream works; quantify and qualify fish habitat values at each of the four locations; identify potential locations to improve existing fish habitat conditions; collect benthic invertebrate samples to determine benthic communities and densities within Trudel Creek; determine fish use within and immediately adjacent to four in-stream work locations; to identify, measure, and characterize lake trout and northern pike spawning habitat in Nonacho Lake; and, to confirm the presence of lake trout and northern pike juveniles and adults in potential spawning areas. 2) Aquatic Biology: establish long-term sampling and monitoring locations along Trudel Creek and at key locations within the Taltson Watershed, including reference locations, to support a robust Aquatic Effects Monitoring Program. 3) Wetland Study: to characterize and map the location, type and extent of wetlands; survey and map wetland ecosystems in the Taltson watershed; use field data collected to identify wetland function; produce a baseline report describing wetland ecosystems in the study area.

Project Description: This licence is being issued for the scientific research application No. 1124. This is a three part study with separate objectives for each. The objectives are as follows: 1) The Fish Study: Evaluate the impacts associated with four locations requiring in-stream works; quantify and qualify fish habitat values at each of the four locations; identify potential locations to improve existing fish habitat conditions; collect benthic invertebrate samples to determine benthic communities and densities within Trudel Creek; determine fish use within and immediately adjacent to four in-stream work locations; to identify, measure, and characterize lake trout and northern pike spawning habitat in Nonacho Lake; and, to confirm the presence of lake trout and northern pike juveniles and adults in potential spawning areas. 2) Aquatic Biology: establish long-term sampling and monitoring locations along Trudel Creek and at key locations within the Taltson Watershed, including reference locations, to support a robust Aquatic Effects Monitoring Program. 3) Wetland Study: to characterize and map the location, type and extent of wetlands; survey and map wetland ecosystems in the Taltson watershed; use field data collected to identify wetland function; produce a baseline report describing wetland ecosystems in the study area. The fish study field program’s methodology is as follows: Aerial photographs of Nonacho Lake will be studied to identify potential lake trout and northern pike spawning zones based on water depth, substrate (if visible), vegetation (if visible) and the extent of the littoral zone. Once potential sites are identified, a subsample of sites will be visited in the field to ground truth the aerial photography. At each site, biologists will identify substrate types and vegetation, and the bathymetry of the near-shore area will be mapped using a high frequency depth-sounder connected to a differential GPS unit. Where water depth is less than one meter, manual depth measurements will be made with a ruler and coordinates will be recorded for each point. The shoreline and water elevation at each site will also be measured using the differential GPS. The water elevation at the time of the survey will be measured in relation to the Nonacho Lake Gauge Datum (NLGD). The Northwest Territories Power Corporation converts these gauge values into a local datum (Nonacho Lake Local Datum, or NLLD) that approximates to mean sea level. Similar areas identified in the aerial photography analysis will also be mapped so that a total area of lost or altered habitat may be calculated. Sampling of fish communities at each site will determine if the area is used by juveniles of the target species. Beach seining, gillnetting and electrofishing will be used to capture fish. Gillnet sets will be limited in duration to prevent mortality. All fish will be identified, measured, weighed and released back to their habitat. No lethal sampling will be conducted, and no age samples will be collected as this information has been collected in the past. Habitat evaluations will follow the guidelines as set out in the “Assessment Methods for Aquatic Habitat and In-stream Flow Characteristics in Support of Applications to Dam, Divert or Extract Water from Stream in British Columbia”. In addition, a habitat mapping exercise will be conducted through an aerial reconnaissance of each location. The aquatic biology field program will include the following areas of investigation: river and lake sediment sampling from various locations within the Taltson Watershed; river and lake benthos sampling from various locations within the Taltson Watershed; water quality sampling from various locations within the Taltson Watershed. The primary components to the proposed wetland classification are: classifying wetlands according to Canadian Wetland Classification System (Warner and Rubec, 1998); mapping wetlands using Geographic Information System and Satellite Imagery; calculation of the area of potentially impacted habitat. Field Assistants will be retained by the study leaders to assist in the Taltson River, Trudel Creek, and Nonacho Lake fish studies. The Smith Landing First Nation, Deninu K'ue First Nation, Northwest Territories Metis Nation, Akaitcho Territory Government, Lutsel K'e Dene Wildlife Land and Environment, Yellowknives Dene First Nation Land and Environment, Tlicho Lands protection, and the North Slave Métis Alliance will be contacted to identify and hire available field assistants. The results of the studies will be made available to all communities by mail, electronically and in person by Deze. In addition, the results of the studies may be incorporated into the environmental assessment of the Project currently underway by the Mackenzie Valley Environmental Impact Review Board. The results will therefore be made available on the Board's web site and reviewed by all participants in the environmental assessment. The fieldwork for this study will be conducted in the Nonacho Lake Control Structure (In-stream assessments will be conducted immediately up and downstream of the Nonacho Lake control structure), Twin Gorges Forebay , Taltson River, South Valley Spillway (SVS) and Trudel Creek from June 8 to September 11, 2009.