Hydrological and contaminant studies in the Marian Watershed, NWT, to enhance community-based cumulative effects monitoring

Regions: North Slave Region

Tags: physical sciences, water quality, paleolimnology, sediment quality

Principal Investigator: Wolfe, Brent BBW (8)
Licence Number: 15857
Organization: Wilfrid Laurier University
Licenced Year(s): 2016
Issued: Apr 04, 2016
Project Team: Roland Hall (Collaborator, University of Waterloo), James Telford (MSc student, Wilfrid Laurier University)

Objective(s): To establish baseline sediment metal concentrations in lakes for reconstructing past hydroecological conditions, and to employ water isotope tracers to characterize lake water balances and complement ongoing aquatic ecosystem monitoring.

Project Description: While water and sediment quality monitoring in areas of industrial developments is an integral part of water management programs to ensure protection of ecosystems, absence of long-term measurements can make it challenging to define reference conditions effectively. As a contribution to the Marian Watershed Stewardship Program (MWSP), this research uses paleolimnological approaches to establish baseline sediment metal concentrations in lakes and to reconstruct past hydroecological conditions. In addition, water isotope tracers are being employed to characterize lake water balances and complement ongoing aquatic ecosystem monitoring.

Fieldwork will include two research components. 1) from the ice surface, the research team will use a hammer corer to retrieve sediment cores from two lakes (Nico and Peanut lakes) approximately one kilometre east of the proposed NICO mine. Both dissolved and surface sediment concentrations of arsenic in these lakes are naturally high relative to other nearby lakes and, therefore, it is crucial to include these lakes in our paleolimnological characterization of baseline sediment metal concentrations. Sediment cores will be analyzed for a suite of radiometric (210Pb, 137Cs), physical (loss-on-ignition) and geochemical (organic carbon and nitrogen elemental and isotope composition, cellulose oxygen isotope composition) parameters, and biota (diatoms, pigments), as well as metal concentrations. 2) Water isotope samples will be collected in 30 ml high-density polyethylene bottles from 15 lakes shortly after snowmelt and ice-break-up, during the mid-summer season, and prior to ice-on, to characterize and assess seasonal variations in the hydrological processes that influence the lake water balances. This approach is particularly well-suited for tracking lake hydrological conditions as part of aquatic ecosystem monitoring programs in northern remote locations. Because there are local concerns stemming from observations of low water levels, which influences access to traditional territory, members of MWSP have expressed interest in incorporating water isotope tracers into their ongoing monitoring efforts.

Prior to conducting fieldwork in late summer, MSc student James Telford visited the community of Behchoko` to further strengthen our partnership with members of the MWSP. James assisted a member from the Department of Culture and Lands Protection, Tlicho Government with the logistical organization of the fieldwork and gave a presentation on the proposed research methods to members of the MWSP. Following collection of sediment cores via helicopter, James participated in an annual community monitoring field course at Marian Lake. Here, additional lake sediment cores were collected and provided hands-on training in these sampling techniques to members of the MWSP. The research team have scheduled the September 2016 field visit so that James can once again participate in the community monitoring field course. James was also asked by the MWSP to present preliminary results at the Geoscience Forum in Yellowknife in November 2015. The research team will continue to seek ways to provide opportunities for local involvement and engagement.

The research team will also deliver community presentations at times linked to the fieldwork and provide plain language reports of findings. The research MSc thesis will also be provided.

The fieldwork for this study will be conducted from April 3, 2016 to September 3, 2016.