Fix coming for leaky Williams Lake dam: ‘There’s just a huge gaping hole underneath’

The days of Williams Lake looking like a fried egg from above during hot, dry summers may be coming to an end.

Work is underway at Shaw Wilderness Park to assess a dam near Purcells Cove Road that’s been leaking for years, lowering water levels and leaving docks around the popular swimming lake high and dry.

“What they’re doing right now is actually the preliminary work to build a new dam,” Brendan Maguire, MLA for Halifax Atlantic, said Wednesday.

“They’re drilling holes. They’re figuring out what kind of dam needs to be built – the structure, how deep it needs to go and all those things.”

‘Play nice’

Dam troubles have been an ongoing issue for the last five years, Maguire said, noting the province’s Progressive Conservative government has committed to the project.

“They’re telling me that new dam will be built by the beginning or the middle of next summer,” said the Liberal MLA.

“I didn’t ever think this day would come. It’s been a long battle. But it shows that, even when you’re in opposition, I think you can get things done if you play nice.”

Maguire, who, as a child, learned to swim in Williams Lake, was alarmed two summers back when the water levels dropped precipitously.

“The summer before (last) was really eye-opening,” he said.

“It wasn’t just that the lake was down. It was that the dam was in such rough shape that there was a lot of worry about if that dam broke and gave way, it would have washed out Purcells Cove Road.”

Cost could double

Past estimates of $1.5 million to fix the dam will likely double for the replacement, Maguire said.

“I heard it could be, potentially, up to $3 million,” he said.

Three studies of the site – the geotechnical work going on now, an archaeological assessment and a biodiversity probe — that are slated to wrap up in March will cost the province just under $100,000, said Jonathan Veale, vice-president of infrastructure, strategy and community development with Build Nova Scotia.

“The idea is that those three pieces of work kind of set the boundaries for what can work from an engineering perspective,” said Veale, an environmental planner.

‘Range of options’

Once the detailed design is complete, “it’s going to give the government a range of options” in terms of whether the dam is repaired or replaced, he said.

“Realistically the dam is quite old, and the materials that were used and the way of construction is not at all what we would do now, and so the range of options around repair are very limited,” Veale said.

“I can’t say it’s impossible at this point. We need to go through the engineering work to determine that.”

It’s unlikely the work to either repair or replace the dam will be completed next summer, he said.

“But work could start and be underway.”

‘Not a dam anymore’

Melanie Dobson, a retired geneticist who lives beside the lake, has measured its changes since 2002. This past summer wasn’t bad because we had record rainfall, but the summer of 2022 saw water levels drop a metre at the dam, she said.

“The problem is that the dam is not a dam anymore,” Dobson said. “It’s just a weir. There’s just a huge gaping hole underneath that bit that you see at the top … So, the water is just pouring through underneath the dam as if the dam wasn’t even there anymore.”

When the weather gets hot, the lake level tumbles, she said.

“As soon as June 1 comes along, we start dropping 2 centimetres a day if we don’t get any rain,” Dobson said.

If the weather gets really hot, the lake level can drop 3 centimetres a day, she said.

“For the migratory birds and everything else that’s there, this is disastrous.”

‘Suddenly a beach’

When the water levels drop, the lakefront that’s now touching and cascading over the dam, can be as much as five metres away from the aging structure.

“There’s suddenly a beach area,” Dobson said.

“So, the water is flowing through cracks well out in front of the dam and able to get well underneath the dam, even when the water level is so low it’s not even near the dam front.”

Murray Coolican, a director of the non-profit Williams Lake Conservation Company, said a lot of water is leaking through the dam and down through Lawson’s Creek, which leads to the Northwest Arm.

While this past summer saw lots of rain, the last four or five summers before that “were as bad as they’ve been,” Coolican said.

Fixes attempted 

The dam has been there in different iterations for 250 years, he said.

“The first dam was in the 1770s and there’s not a good record of what the various changes were over the years,” Coolican said.

“There was a time when some of the local residents put stones inside wire cages and bags of cement and stones on top … Those reinforcements have helped with the structure of the dam that’s visible, but it hasn’t really helped that much with the leakage that’s going underneath.”

‘Right direction’

Margo Kerr of the Williams Lake Dam Association hopes the problem is fixed soon.

“This is really going in the right direction – getting the boreholes done,” Kerr said of the work going on right now.

When the water level dropped in past summers, “it was so depressing,” she said.