Municipality Continues To Monitor Erie Shore Dr. Flooding Issues

The Municipality of Chatham-Kent is keeping flooding issues along Lake Erie on its radar and continuing to monitor the shoreline.

An information report with an update on the floodproofing measures on Erie Shore Dr. was presented at Monday night's council meeting. Last December, the following three-part motion was passed:

1) That the Municipality of Chatham-Kent appoint an engineer to design a system of flood proofing such as direct drilled catch basins and drains to protect and alleviate on-road flooding of the Dyke Rd. 2) A stakeholders committee be convened to determine a fair and equitable strategy to cover the expenses for the engineering and costing of the recommendation outlined in the 1998 Todgham and Case report. 3) Chatham-Kent Council demand that some of the money allocated to the Great Lakes Basin by the Federal and Provincial Governments be allocated to alleviate flooding issues along the Lake Erie Shoreline in Chatham-Kent.

Infrastructure and Engineering Services (IES) prepared and released a Request for Proposal (RFP) in late December of 2017. At the same time, geotechnical firm Golder Associates was retained to conduct specific soil composition and hydraulic testing on the dike itself. The draft Golder report was made available to all interested RFP participants.

The closing date for the RFP was February 14 of this year. No formal submissions were received.

The 1998 Todgham and Case study was a preliminary report. A more detailed final report with updated cost estimates, revised design options, and assessment rationale is required before any construction can begin. Approvals are also required from various federal and provincial government agencies.

Chatham-Kent was approved for funding under Canada’s Climate Change Adaptation Platform. According to the information report, this funding is intended to support a study that will assess the effect of climate change on the Great Lakes using the Lake Erie Shoreline in Chatham-Kent as a case study.

Work on the public consultation and preparation of the report will occur over the next 18 to 24 months. The study will develop a Chatham-Kent Integrated Shoreline Management Plan Incorporating Climate Change Adaptation. It will use future ice conditions and storm extremes for Lake Erie coastline to assess coastal hazards, such as flooding and erosion, and co-develop a vulnerability assessment and adaptation response strategies.

After no responses were received to the RFP, administration instructed Golder Associates to perform additional work to analyze and provide recommendations on the condition of the road and the dike.

The report concluded that the dike slope is stable under normal conditions. The existing roadway pavement structure was deemed adequate for the traffic volumes and loading conditions. The report also points out that the dike slopes are likely to become unstable during extended significant flooding events that between three and eight days.

The following recommendations were made for the short term and are all currently in progress:

•  Continue to monitor the slope weekly during peak flooding times.
• Continue to monitor erosion and scour along the drain slopes.
• Continue to control overtopping in designated sections of the dike and incorporate robust geosynthetic reinforcement and erosion control in those sections as required.
• Continue with riprap-lined channels to manage the flow of floodwaters down the slopes into the drain.

The following recommendations were made for the long term:

• Perform a detailed topographic survey to support the relocation of the drain to the north and regrade the dike slope to a 2:1 incline.
• Alternatively, remove the upper 2.5 m to 3 m and reconstruct as a reinforced soil structure in accordance with the Drainage Act.
• Work with higher levels of government to study the feasibility and approvals for off-the –shoreline wave energy absorbing systems (i.e. breakwalls).

The report does not recommend that any below ground surface drainage systems, such as direct drilled catch basins, be installed along the roadway and through the dike as it may lead to further instability of the dike slopes.

The cost of the Golder Associates report was $16,800 plus HST.

**CORRECTION -- A previous version of this story indicated there would be a public meeting on July 31 re: flooding issues along Erie Shore Dr. Municipal staff have confirmed at this point, there are no plans for any future public meetings the issue and that the report that was presented to CK Council Monday contains is the most up-to-date information they have at this time**