Northwest Territories Power Corporation Twin Gorges Aquatic Effects Monitoring Plan and Sediment and Erosion Management Plan
Principal Investigator: Byrne, Geraldine (1)
Licence Number: 15309
Organization: Northwest Territories Power Corpoation
Licenced Year(s): 2013
Issued: Aug 02, 2013
Project Team: Geraldine Byrne (Project Manager, NTPC), To be determined, To be determined

Objective(s): To monitor and identify potential short-term, long-term and cumulative changes throughout the Taltson River aquatic environment and to identify if there are areas or sites on Nonacho Lake and Trudel Creek that are sensitive to erosion and erosion processes.

Project Description: The Aquatic Effects Monitoring Plan (AEMP) and Sediment and Erosion Management Plan (SEMP) are requirements under water license MV2011L0002 issued by the Mackenzie Valley Land and Water Board (MVLWB). The objective of the AEMP is to monitor and identify potential short-term, long-term and cumulative changes throughout the Taltson River aquatic environment. The objective of the SEMP is to identify if there are areas or sites on Nonacho Lake and Trudel Creek that are sensitive to erosion and erosion processes.

Aquatic Effects Monitoring Program
2013/14 Work:
Trudel Creek and Lower Taltson River Fish Stranding Monitoring:
The turbine at the Twin Gorges powerhouse has to be shut down to conduct annual maintenance. This results in a potential increase in water surface elevation which could result in isolating and potentially stranding fish. Specific activities consist of:
- Identify fish species and life-stage usage of littoral zone habitat and preferred habitat conditions of each identified species;
- Conduct an external exam of captured fish for cysts and parasites and provide general comments on fish health;
- Monitor fluctuations in habitat conditions (depth, velocity, cover and substrate) and vegetation communities;
- Monitor changes in water quality and temperature; and
- Monitor fluctuations in fish species composition, condition, and age.

Mercury in Sediment and Fish Flesh Monitoring:
Monitor mercury concentrations in sediment and fish flesh within the Taltson River from Nonacho Lake to Twin Gorges facility. Specific activities consist of:
- Collect mercury concentration levels within sediment and fish flesh within Nonacho Lake, Trudel Creek and Rutledge Lake;
- Identify trends in mercury concentrations;
- Determine if mercury concentrations in fish are above the CCME guidelines for human consumption and for the protection of aquatic life; and
- Conduct an internal examination of sacrificed fish for parasites, stomach content analysis, aging structures and stable isotope analysis.

Desktop Fish Mortality Assessment:
- Evaluate the probability of fish entering the penstock inlet in the Twin Gorges Forebay and become entrained through the turbines.

NTPC is planning to hire two local aboriginal people to help with the 2013 field program. NTPC will be working with communities in the project area to identify and hire two field assistants who will help with field work.

Under the conditions of water license MV2011L-0002, NTPC is required to submit an annual AEMP report by March 31 that summarizes and presents results of work done under the AEMP during that year. This report is available to the public via the MVLWB's on-line public registry.

The fieldwork for this study will be conducted from August 2, 2013 to October 31, 2013.