CBRM says earthen berms helped reduce flooding in Sydney after rainy weekend

While parts of Nova Scotia were left submerged by a powerful weekend rainstorm, controversial earthern berms are being credited with reducing the impact in Sydney.

The Wash Brook that runs through the Baille Ard Forest and a south end residential neighbourhood flooded seven years ago, costing the provincial government about $15 million and the Cape Breton Regional Municipality nearly $5 million and causing 18 homes to be torn down.

Over the weekend, water in the brook spilled over the banks, but didn't flood the streets as it did on Thanksgiving Day in 2016, when more than 225 millimetres of rain fell in one day.

Some people objected last year when the municipality started removing trees and digging up mounds of earth to create the large berms to hold back excess water, saying it would ruin the trails and have little effect on flooding.

But Baille Ard Recreation Association president David Gabriel said the berms have proven their worth.

"I'd say that the berms were doing something, because the water that we were seeing on the trails didn't seem to have affected the downstream, which was the whole point," he said.

CBRM has spent about $4 million on flood mitigation measures, including outlet controls on two lakes upstream and the construction of the berms.

Over the past weekend, some parts of Nova Scotia received more than 200 millimetres of rain in under a day, while some areas of CBRM received up to 150 millimetres of rain over 48 hours.

Gabriel said he wasn't sure whether the weekend flooding in the forest caused any damage on the trails.

He said it looked like the water was being held back by the berms, but that it was also spilling back into the brook.

"I'm a bit puzzled by that," he said. "I thought that the water would be held and gradually be allowed to go back into the brook, but I'll have to talk to the engineering department in CBRM to see if I just misunderstood or if they have to do something to affect a change in the way the water left the berm."

However, the end result was that homes were spared, he said.

"There was no flooding down below and everybody that's involved in the trails is ecstatic about that — and in the community, I'm sure," Gabriel said.

"That's what we wanted to happen."

CBRM spokesperson Christina Lamey said municipal engineers checked on the flood controls on Monday after the heavy rain.

"The berms worked to an extent in this most recent storm event, in that they held water and essentially they throttled water at the bottom," she said.

"The report back from this morning was that the berms were holding water and they're literally still releasing water now. Here we are, 24 [to] 48 hours after a lot of the rain [and] they're still more slowly releasing that water into the water system below."

The Mud Lake flood control outlet is done and the municipality still has some work to do on the Gilholmes Lake outlet, but that should be finished in the next few weeks, Lamey said.

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