Peace Project Water Use Plan - BC Hydro

Peace Project Water Use Plan
Annual Report: 2010
5.1.17.3 Status
on lake whitefish (Coregonus clupeaformis) and kokanee (Blackman et al. 1990;
Stewart et al. 2007). Grayling, and mountain whitefish (Prosopium williamsoni), have
suffered drastic population declines since the early 1980’s when stocks were
reported healthy in the reservoir and its tributaries (Northcote 2000; Blackman 2001).
Grayling now appear to be restricted to a small number of watersheds above the
W.A.C. Bennett and Peace Canyon Dams and are estimated to be less than 1% of
their original population (McPhail 2007). As a result, the grayling (population 1) is
red-listed in BC (B.C. Minist. of Environ. Victoria 2009) and requires considerable
attention to support recovery of the population. Arctic grayling depend on the lower
reaches of larger mainstem rivers or the reservoir embayments that these
watercourses empty into for adult rearing habitat (Clarke et al. 2007; McPhail 2007).
The Peace/Williston Fish and Wildlife Compensation Program (PWFWCP) has
collected a large body of data relevant to the perceived tributary access impacts to
native fishes linked to reservoir development since the program inception in 1988
and a significant amount of resources have been expended to develop potential
compensation solutions since the creation of the reservoir, but as of yet little work
has been done implementing previously proposed mitigation recommendations
(Langston 1992; Fielden et al. 1993; Langston and Blackman 1993; Morgan 1995;
Aquatic Resources Limited 2002).
This report attempts to reconcile previous recommendations with a practical and
thoughtful approach to designing an experimental trial using proven mitigation and
restoration techniques to improve fish access to affected tributary systems. Although
we are not aware of any previous examples of similar remediation projects
implemented in reservoirs elsewhere, the designs we recommend have been
successfully implemented in many stream mitigation and restoration projects and
follow recognized hydrologic design principles (Newbury and Gaboury 1993).
Specifically, our objectives are to improve or restore fish access to fluvial habitats
isolated by LWD accrual and /or drawdown effects resultant from normal reservoir
operation, with a focus on increasing access to available habitat of listed and
regionally significant fish. This report discusses:
� Inventory and ranking of candidate tributary sites
� Biophysical description of 2 sites recommended for trial mitigation
� Conceptual design recommendations for mitigation works to restore access
and improve fish habitat at tributary mouths by rehabilitating channel
characteristics at elevations between the low and high water levels:
� Management / maintenance plan for physical works
� Cost estimate for proposed physical works
This project is complete.
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