Jimmy Jimmy (Judd) Slough – Dike Upgrade

Overview

Squamish River Dike at Jimmy Jimmy (Judd) Slough project will raise approximately 900 metres of the Squamish River dike on private land between Wai’wakum Reserve and Aik’wuck’s, widen the dike crest from four metres to six meters, provide rip-rap erosion protection for the raised portion of the dike, add a new vehicle turnout, and upgrade one access ramp.

Background

The District of Squamish completed an Integrated Flood Hazard Management Plan (IFHMP) in 2017 which laid out a prioritized list of dike upgrades to raise the standard of flood protection for the community. The highest priority project was to upgrade the Squamish River dike at Upper Jimmy Jimmy (Judd) Slough to meet provincial requirements so that the dike can withstand a 1 in 200-year return period flood with 0.6 metres of freeboard.

  • This project was established as the highest priority due to the IFHMP concluding that failure of the dike could result in direct damage totalling $190M (2016$) and displace up to 7,000 residents in the neighbourhoods of Brackendale, Garibaldi Estates and several Squamish Nation reserves.
  • This section of dike also protects significant community and regional infrastructure including Highway 99, CN Rail mainline, wastewater treatment plant and several major drainage pump stations. A dike breach would cause significant social and environmental impacts due to the flooding of homes and businesses.

This upgrade was completed in 2019.

The IFHMP also recommended a longer-term priority to raise the local standard of protection for the Squamish River dike beyond provincial standards, to meet a 1 in 500-year return period flood (see Figure 1 below for details). This increase of standard was recommended in recognition of the substantial community development that relies on the protection of the Squamish River dike. In anticipation of this future upgrade, the 2019 upgrade widened the footprint of the dike so that future upgrades would only need to raise the dike without requiring any additional space.

super dike diagram

Project Information

The proposed scope of work will:

  • Raise approximately 900 metres of the Squamish River dike on private land in between Wai’wakum Reserve and Aik’wuck’s
  • Reserve as shown in Figure 2 below.
  • Widen the dike crest from 4 metres to 6 metres.
  • Provide rip-rap erosion protection for the raised portion of the dike.
  • Add new vehicle turnout.
  • Upgrade one access ramp.

Project location map

Proposed Project Schedule

2023/2024           Detailed design and permitting

Fall 2024               Begin construction

Project Funding

The District has applied for a grant of $5.4 million, which provides up to 73.3% of funding. If the grant application is successful, the remaining cost of the project is proposed to be funded through borrowing to spread the cost of the project out over time, ensuring that future taxpayers also support the upgrade. $1,818,182 of this project is proposed to be financed by debt. The annual taxpayer impact represents approximately $0.68 per $100,000 of assessed residential property value.


Project Contact

Please contact Valentina Fazio, Engineering Technician Coordinator at [email protected] with any questions.


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Comments

  • jeff May 23, 2024, 10:28 PM (30 days ago)

    was this dyke not just upgraded a few years ago

  • Pierre Friele Sep 23, 2023, 1:03 PM (9 months ago)

    While it might be year 500 return for clear water, it is directly down from Cheak/Cheekye confluence and sedimentation has not been factored in to freeboard analysis. It it disingenuous, and misleading to the public, to assign a return interval. Super dike is a better term, likely with a safety factor less than 500 yr return.

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