Repair or replace: Fate of Sasamat Lake dam still in the air

·3 min read

Three years after seepage was found at a dam on Sasamat Lake, a plan to address the issue has yet to be finalized.

The options: repair or replace.

During an inspection three years ago, the Ministry of Forests, Lands, Natural Resource Operations and Rural Development noted seepage at the dam – which is located in the northwest corner of the lake – and tasked Imperial to find a fix.

The initial idea was to repair the dam but that would have been a temporary solution, said Ali Tejpar, Imperial’s project manager for the Sasamat Lake dam. The dam is at its end-of-life.

“Imperial’s responsibility is to really ensure that the dam is adequately maintained and safe,” he said.

Tejpar went over the two options currently being explored by Imperial during a presentation to Belcarra council on Sept. 6.

In the replacement scenario, the dam would be replaced “like for like” with a dam designed to current regulations and there would be limited change to the lake’s water levels.

In the decommissioning scenario, the current structure would be removed “down to [the] bedrock.”

“We would see the water level would reach a more natural state,” said Tejpar. Studies suggest the water would drop about two metres.

Both scenarios include a pedestrian bridge to cross either the new dam, or the outlet at Windmere Creek.

Coun. John Snell asked what effect the water level dropping would have on White Pine Beach, a sandy recreation destination for many in Metro Vancouver.

Imperial representatives said there may be an impact to the recreation infrastructure, but they don’t know exactly what. Their studies with project partner Stantec have been focused on wildlife and the environment.

Studies so far suggest there would be “limited temporary” impact to fish and fish habitat in both scenarios, as well as limited impact to vegetation and wildlife around the dam footprint.

In the decommissioning scenario, with the water dropping two metres, a Stantec geotechnical engineer said there would be a temporary impact to fish in the shallow water while new wetlands form.

A flood routing study for Windermere Creek suggested there would be no impact to houses or bridges in a rainfall event.

The company is continuing its geotechnical exploration as well as gathering feedback from First Nations and stakeholders.

A decision on which option will be pursued is expected before the end of the year.

The Imperial Oil-owned dam was first built more than 100 years ago—long before umbrellas and beach towels littered White Pine Beach or campers paddled canoes from Sasamat Outdoor Centre—to support the company’s oil refinery in Port Moody.

In the 1960s, a replacement dam was built, which is the infrastructure you see there today.

When the refinery was converted into a terminal in 1995, Imperial began drawing less water from Sasamat. The water, which flows out of the lake into Windmere Creek is used in firefighting emergencies.

Marissa Tiel, Local Journalism Initiative Reporter, Tri-Cities Dispatch