Stanley Park Beaver Lake: Custom Box Culverts with Fish Ladders to Improve Ecosystem

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The iconic 405-acre Stanley Park borders downtown Vancouver, British Columbia, and sits pristinely on Burrard Inlet offering visitors a unique glimpse at what the natural setting of Vancouver looked like before urbanization. Nestled inside Stanley Park is Beaver Lake, which is one of the very few freshwater lakes existing in Vancouver, and the outlet Beaver Creek is one of only three remaining riparian waterways in the city of Vancouver.

The Beaver Lake Restoration Plan includes an effort to improve the ecosystem of the lake, and in Phase 1 the use of precast concrete Box Culverts with fish ladders and custom Headwalls to upgrade the lake’s outlet stream was conceived. By improving the flow of freshwater to Burrard Inlet and thereby enhancing the channel characteristics of the outlet, it is hoped that many native species will be encouraged to pass through and thereby populate the lake.

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Precast concrete box culverts supplied by the Langley Concrete Group, which are designed in accordance with ASTM C1433M specifications, were selected with inside spans of 3.35 m and internal rise of 1.52 m and in lengths of 2 m weighing 17,560 kilograms each. In each of the five sections, variable-height custom fish ladders with staggered rectangular low-flow notches were cast at the inverts of the precast box culverts. Pooling waters flowing between the seven fish ladders should facilitate the necessary water for fish to pass the vertical incline from Burrard Inlet to Beaver Lake. At each end of the run of precast concrete box culverts, Langley Concrete Group also supplied 4.1 m span headwalls for both inlet and outlet control structures.

Jack Tupper, Landscape Architect – Park Development (City of Vancouver) provided a project write-up. The following is an excerpt from his report:

“In the fall of 2020, as part of the Beaver Lake Enhancement Masterplan, the City of Vancouver worked with a team of consultants and contractors to install Phase 1 of the project; a newly improved Beaver Lake Outlet.

“With dramatic fluctuations in water levels, this new larger and more robust outlet is able to balance lake levels throughout the year and provide continuous flow into the adjacent Beaver Creek. Even the growing population of beavers, that inhabit the appropriately named lake, struggle to block the new structure entirely.

The new outlet is the first step in rejuvenating Beaver Lake and its ecological health.”

Jason Omelaniec
Technical Marketer
Precast Producer: Langley Concrete Group