Coats Marsh weir replacement RFP open

·2 min read

The Regional District of Nanaimo is now seeking bids for the replacement of the weir in Coats Marsh Regional Park.

A request for proposals went out June 27 for firms to produce a study on the optimum elevation of a replacement to the concrete weir in the park. The study and report, to be completed by the end of October, will involve a comparison of the costs, environmental impacts and long-term risks of three potential weir elevations.

The three weir elevation scenarios to be studied are reinforcing or replacing the weir at the existing elevation, raising the weir to match the existing beaver dam and raising the weir to an intermediate elevation above the existing weir and below the top of the beaver dam. Construction costs, environmental impact and management of long-term hydrological risk – downstream flooding – are the main considerations for determining the ultimate elevation, the bid document says.

In 2021, the RDN installed siphons to lower the water level behind the beaver dam near the weir, saying the level, which increased as a result of the dam, had affected the integrity of the weir and could present liability issues if there is a breach. Installation of the siphons, including professional fees, cost $46,320.

“The long-term management goal is to phase out the siphon system in order to return the marsh hydrology to a more naturally regulated state and to protect wetland habitat,” the bid document says.

In 2020, a weir assessment report was completed by Scott Merriam, which noted the weir showed signs of deterioration, including cracks and spalling. The siphon installation followed a September 2021 water level management strategy completed by Madrone Environmental Services. A 10-year management plan for the park was completed in 2011. A review of the plan is not in the RDN parks’ work schedule at this time.

Rachelle Stein-Wotten, Local Journalism Initiative Reporter, Gabriola Sounder

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