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Sediment leaks into Fall River water supply during bridge repair

Fall River's McQuarrie Bridge reopens to traffic

Sediment leaked into a lake used as a water supply outside Halifax during construction to repair a bridge Friday afternoon.

Crews with Dexter Construction are repairing McQuarrie Bridge in Fall River, N.S., at an estimated cost of $1.3 million to the municipality.

That work has been halted until the cause of the leak in Lake Thomas can be determined, provincial environment department spokeswoman Krista Higdon said in an email late Friday.

Higdon declined an interview. It's unclear how the concentrated sediment might affect the lake's ecosystem.

Water not contaminated

The water that leaked is not contaminated, as it came directly from the bottom of the lake, but water that makes it to household taps may contain more silt than usual, municipal spokesman Brendan Elliot said.

"This is more of an issue for the environmental impact on the water way than it is for the human side of things," he said in an interview.

Water from lake's bottom

Crews have to drain the water around the current bridge footings in order to fix them.

That water drawn from the lake's bottom will be put into a shallow part of Lake Thomas, like a containment tank, surrounded by two booms — like barriers — to prevent leakage.

When the bridge repairs are done, that water will be filtered and returned.

But somehow that silty water leaked through the booms, Elliot said. A photo he provided to CBC shows brown water spread out past the containment pond's barriers.

Check filters

That means a higher concentration of silt mixed into regular lake water.

Homes and businesses draw water from Lake Thomas and nearby Lake Fletcher, so owners should check their filtration systems are working properly, Elliot said.

"The bottom line is that water, no matter what, should not be ingested without being filtered first," Elliot said.

Still on time

Work will resume only when the cause is determined, as is spelled out in Dexter's contract, Elliot said. That means, no compliance order needed to be issued, he said.

The project is expected to still be done on time by August 26, as a bit of "wiggle room" was built into the schedule, he said.