NWT RESEARCH DATABASE

Regions: Gwich'in Settlement Area

Tags: physical sciences, water quality, sediment, benthic invertebrates

Objective(s): To determine the impact of ferry landings on water quality and traditional fish harvesting in the Mackenzie and Peel Rivers.

Project Description: Fishing is an important part of the Gwich’in way of life. Concerns in the Gwich’in communities of Fort McPherson and Tsiigehtchic have arisen with regards to the use of granular material in ferry landings. Anthropogenic sediment from ferry landings has the potential to alter river ecology downstream thus impacting valuable fish habitat. This objectives of this project are to determine the impact of ferry landings on water quality; evaluate impact of granular material from ferry landings on river bed characteristics; determine impact of granular material from ferry landings on benthic invertebrate communities; and to examine the perceived impacts of ferry landings on the community. After ice-breakup the team will measure sediment movement (suspended, bed load, substrate), water quality, and collect invertebrate samples from the Mackenzie and Peel Rivers. Suspended and bed load sediment samples will be collected at six cross-sections of each river, three upstream of the ferry landings and three downstream. One additional cross-section will be established at the Tsiigehtchic ferry landings near the mouth of the Arctic Red River. Along each cross-section, five points will be sampled three times before the construction of the landings and three times after. Sampling dates will be spaced three days apart in order to sample both rivers in the field season (i.e. the crew will be moving back and forth between the Mackenzie and Peel Rivers). Using a boat to navigate, the research team will deploy a Helley-Smith bed load sediment sampler and a DH-2 depth-integrated sampler at each designated sampling point. Each depth-integrated sample will be measured for turbidity, pH, temperature, conductivity, and dissolved oxygen. Substrate and invertebrate samples will be collected with a Petite Ponar Grab at each sampling point before and after the construction of the landings. Bathymetric and substrate maps will be created using a Humminbird depth finder to further characterize sediments in each river. In the lab, particle size distribution and dry weight will be determined for all three sediment types. A difference in particle size, total suspended solids, or bed load sediments downstream after construction will indicate that ferry landings are affecting the habitat downstream. Invertebrates will be identified and used to determine if community composition differs downstream of the landings. Findings will be reported to the Gwich’ya Gwich’in Renewable Resource Council, the Tetlit Gwich’in Renewable Resource Council, and the Department of Infrastructure. The study will aid in decision-making with regards to the operation of the current ferry service, and will provide results of interest for future development of ferry crossings in the region. The results of the study will be presented at a community meeting after the second field season in 2019. A final report will be submitted to the Department of Infrastructure and will be distributed to the Renewable Resource Councils in Tsiigehtchic and Fort McPherson as well as to the Gwich’in Renewable Resources Board. The research team will also publish results in refereed scientific journals and seek to gain media coverage for that work by working with the Laurier Communications and Pubic Affairs Office. The fieldwork for this study will be conducted from May 20, 2019 to June 30, 2019.