Young gravel-pit lakes along Canada’s Dempster Highway: How do they compare with natural lakes?

ABSTRACT

Gravel-pit lakes are a common feature of many human-modified landscapes throughout the world. In Canada’s north, they are often formed when gravel is extracted to construct dams, bridges, and highways. Past studies suggest that gravel-pit lakes differ from natural lakes in terms of their morphometry, water quality, and biological communities. In this study, we compared gravel-pit and natural lakes by sampling lakes between Inuvik and Fort McPherson in the Northwest Territories. We collected lake morphometry, water quality, and biological data (zooplankton, macroinvertebrates, and fish presence) from six gravel-pit lakes and fifteen natural lakes. In comparison to natural lakes, gravel-pit lakes were four times deeper, two times clearer, and five times smaller in their surface area. In addition, important nutrients, including phosphorus and nitrogen, were significantly lower in gravel-pit lakes. Despite the differences in morphometry and nutrients, pelagic zooplankton and littoral macroinvertebrate communities did not differ significantly between the two lake types. Therefore, we conclude that despite their recent formation and unnatural morphometry, gravel-pit lakes along the Dempster Highway can support invertebrate communities typical of natural lakes in the region.

KEYWORDS:

• Gravel pit
• borrow pit
• water chemistry
• zooplankton
• macroinvertebrates
• Northwest Territories
• Dempster Highway
• Gwich’in Settlement Area

Acknowledgments

This work was carried out under Northwest Territories Scientific License number 16126. We would like to thank the Gwich’in Renewable Resources Board and the Renewable Resource Councils in Fort McPherson, Tsiigehtchic, and Inuvik for supporting the project. L. Waters, Y. Langille, C. Tward, L. Lopez, and M. Teillet assisted with field data collection. Alexandra MacDonald at the Gwich’in Land and Water Board provided access to government records on gravel pits and historical topographical maps of the region. Logistics support was provided by the Aurora Research Institute. G. Braun and Dr. H. Gray at The Center for Cold Regions and Water Science Analytical Laboratory provided assistance with Ca, TN, TOC, and TP measurement. Dr. S. Arnott assisted with analysis of chlorophyll-a concentrations. Funding was provided by the Northwest Territories Cumulative Impacts Management Program under project CIMP197 and by Wilfrid Laurier University.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Northwest Territories Cumulative Impacts Management Program [CIMP197].