Water Stewardship Information Sources
| Citation | BC Conservation Foundation. 2009. Cheakamus/Squamish River Engineed Log Jam Pilot Project. Prepared for BC Hydro. |
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| Organization | BC Hydro |
| URL | https://www.bchydro.com/bcrp/projects/docs/lower_mainland/09_CMS_04.pdf |
| Abstract/Description or Keywords | Fish use in the mainstem Squamish and low-gradient reaches of its major tributaries includes all five pacific salmonid species (coho, chinook, sockeye, chum and pink), steelhead and sea-run cutthroat and char. Although the reduction in several salmonid species in Squamish River over the past five decades is noted in many Georgia Basin streams, and may be related to common limiting factors, it has been proposed that several specific impacts have acted to reduce the quality and quantity of rearing habitat. There is a distinct lack of stable rearing habitat in the mainstem channels of Squamish River watershed, much of which would have once been provided by stable instream LWD. The importance of replacing instream large woody debris (LWD) in the Squamish River watershed for this purpose has been acknowledged in many technical reports. The Cheakamus-Squamish River Engineered Logjam Pilot Project was initiated to address some of the broader instream habitat limitations affecting the basin, in particular the issue of LWD habitat. A reach within the lower section of Cheakamus River was selected as being suitable for installation of LWD structures to emulate the natural function of logjams that have historically had a significant role in channel form and process. A log jam was recently installed by BCCF at Site 2 within this treatment reach. This report outlines the rationale and design conditions under which a similar log structure has been designed at Site 1 within the same reach. The purpose of the Site 1 structure is to address impaired instream fish habitat values as well as to provide additional stability at the head of a threatened side-channel. The structure would work in concert with the existing jam, which has become weakened, to help prevent further loss of riparian forest and control flows into the side-channel. The proposed structure would span approximately 120 linear metres of bank and be comprised of 73 individual logs. Boulder ballast would be used to overcome the buoyant forces acting on the logs while piles would be driven into the river bed to overcome the sliding forces of the velocity component of the flow. Similar construction methods would be used as were employed to successfully install the log jam at Site 2 in April and May of 2010. |
| Information Type | report |
| Regional Watershed | Howe Sound & Sunshine Coast |
| Sub-watershed if known | Squamish River, Cheakamus River |
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| Project status | complete |
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