Engineering firm addresses cost and prospects of Sumas Lake return

In developing the City’s Flood Mitigation Strategy, the City of Abbotsford contracted Kerr Wood Leidal (KWL) Associates Ltd., a renowned consulting engineering firm specializing in water infrastructure, to conduct a full post-flooding analysis of Sumas Prairie with a specific view of reducing flood risk for residents, businesses and agricultural properties. This work is the foundation behind the City’s preferred Long-Term Flood Mitigation Plan and federal funding application.

When UBC released their journal article published on Frontiers in Conservation Science titled “Reclaiming the Xhotsa: climate adaptation and ecosystem Q1 restoration via the return of Sumas Lake”, the City approached KWL once again to review the article and provide some substantiation of the claims and direction proposed in the document.

KWL provided the City with an analysis of the article sharing, “the article’s assessment of the potential costs for retreat from the former lake bottom area is grossly underrepresented,” and, “the article reflects only limited knowledge of the ongoing flood mitigation work being undertaken by the City (with the support of KWL), and makes no reference to the important discussions ongoing in the Sumas River Watershed Flood Mitigation Plan (SRWFMP) and Nooksack River Transboundary Flood Initiative (TFI) collaborative planning processes, both of which recognize the critical need for Indigenous participation.”

Some of the observations made by KWL are similar to those documented in a recent article published by the Fraser Valley Current, which states “a restored lake would either increase the flood threat for surrounding areas, or require costly new flood-prevention infrastructure,” adding that the “expenses would go far beyond just the price to buy out owners on the Sumas lakebed.”

The KWL engineering report acknowledges the value of the UBC article’s content regarding Indigenous history, perspectives and interests and goes on to further address several of the theories made in the UBC research article and provide additional professional assessments of the viability of a return of Sumas Lake.

The City of Abbotsford is making this report available to ensure that the public can engage in a fulsome understanding of the complexities involved in addressing the serious flooding concerns and extreme climate impacts related to the rivers, waterways and flood infrastructure of Sumas Prairie. The City of Abbotsford will continue to work with the Province of BC, local First Nations and other partners on the SRWFMP and TFI, and advocate for the needs of Abbotsford, residents, farmers and businesses.

Additional information:
•    KWL Technical Memorandum