Arrow Lakes foreshore survey report now available
As the popularity of Arrow Lakes grows, both as a recreational hotspot and a scenic place to live, monitoring the lake foreshore is just as important as monitoring lake water quality.
The lake foreshore is defined as the area along the lake between the low and high water mark, and is extremely valuable ecologically, culturally and economically. Around ninety percent of all lake biodiversity is found in the foreshore; it provides habitat for fish, nesting waterbirds, breeding amphibians, shorebirds and more. Culturally and archaeologically-significant sites may be found there. Erosion, flooding, and waves all impact the foreshore, and can cause extensive damage to properties and habitats.
Negative impacts and changes to lake foreshore can occur slowly over time and can also be difficult to detect. Living Lakes Canada has studied the foreshore of Arrow Lakes using a federal monitoring protocol called Foreshore Integrated Management Planning, or FIMP.
FIMP lake surveys can determine how much the lake foreshore health is changing over time. The monitoring can also highlight the effectiveness of lake management policies implemented by all levels of government as well as considering important Indigenous cultural values, Species at Risk and their habitat.
Arrow Lakes FIMP survey in July 2022. LLC Photo.
“The Arrow Lakes reservoir is a complex system, one that has been greatly modified and impacted by humans. Multiple dams influence Arrow water levels and preclude fish migratory access on the Columbia system,” said Georgia Peck, FIMP Manager with Living Lakes Canada. “Post flood, critical foreshore habitats do remain and the goal of the 2022 Arrow Lakes FIMP project was to identify these high value habitats, provide baseline data, and inform future land use planning around the reservoir shoreline with evidence-based recommendations.”
The foreshore survey was carried out by boat using GPS, and drone assessment. The comprehensive survey cataloged multiple observations: land-use (industrial, residential, commercial), shore type (cliff/bluff, rocky shore, sand beach), foreshore condition, the number of docks, weirs or other man-made developments, wildlife, vegetation, and many others.
The 2022 Arrow Lakes FIMP findings can be found in a report in the Columbia Basin Water Hub database, including Foreshore Development Guidelines.
“The Foreshore Development Guidance document is a resource that can be referenced by government, First Nations, stewardship groups, property owners, or anyone wishing to learn more about the quality of habitat on the foreshore and the risks posed by different shore-altering activities,” said Peck.
In the case of the FIMP Arrow Lakes survey, the “natural” shoreline is based on the human-made reservoir, rather than any dam disturbances to the original shoreline ecosystem.
The FIMP study area is the section from Hugh Keenleyside Dam upstream to Arrowhead/Shelter Bay. This study area includes an approximate 425 km of shoreline, which has been broken into 185 continuous segments. The northernmost section extending upstream to Revelstoke (or the Revelstoke Reach) was not included.
The survey determined that the most common shoreline modifications were: docks (210), gravel and concrete boat launches (189), retaining walls (103), and groynes (97). Other disturbances included substrate modification (36,007 metres; 7%), erosion protection (14,259 m; 2.8%), road (2.4%), retaining walls (0.7%), and rail (0.9%).
Overall, the ecological integrity of Arrow Lakes was largely rated as Moderate (42.8%), followed by High (28.3%), Very High (15.6%), and Low and Very Low (13.3%). At full water level, 87% (440,241 m) of the shoreline was in a natural condition, while the remaining 13% (67,241 m) was disturbed.
Arrow Lakes is the largest lake ever to be surveyed by the Living Lakes Canada FIMP team and included a high level of involvement and support by Splatsin First Nation.
“The foreshore ecology and development of Arrow Lake were thoroughly assessed in the 2022 FIMP survey, which established a detailed baseline for the current condition of the lakefront,” said Richard Johnson, P.Eng, Arrow Lake and Environment Stewardship Society. “This data will enhance our understanding of the lake’s foreshore and our existing knowledge, and will also facilitate the identification of ecologically sensitive zones. The report is very detailed and will form the basis for further studies of the foreshore habitat of Arrow Lake. The extensive bibliography is very helpful to researchers.”
Living Lakes Canada entered a four-year Contribution Agreement with Fisheries and Oceans Canada (DFO) and their Canada Nature Fund for Aquatic Species at Risk Program in 2019 to review and revise the FIMP methodology and map or re-map up to eight lakes. To date, four lakes have been surveyed for the first time and six lakes have been re-surveyed through the program.
To learn more, email georgia@livinglakescanada.ca.
