$8.8 million Moosomin Dam rehab on schedule

February 19, 2024, 7:58 am
Ryan Kiedrowski, Local Journalism Initiative Reporter

Work continues on the Moosomin Dam Spillway Rehabilitation. Because of work on the spillway, and aeration added to Moosomin Lake because of the lower water levels made necessary by the construction, there are areas of thin ice on the lake.

Thanks to an overall milder than average winter, work at the Moosomin Dam has been staying close to the schedule.

“The last time I was out there, looks like they’re about three quarters of the way up the spillway,” said Mayor Larry Tomlinson. “So they’re doing pretty good.”

He noted that as cement is poured, a roof is build over top in order to provide heat. Last week noted the final big pour of the project and the bulk of work at the dam should wrap in the next month.

“What we’re doing is making it safer, more durable, during a high flow events so that it could otherwise compromise the integrity of the structure,” said Water Security Agency spokesperson Patrick Boyle.

A 300mm thick concrete slab was added to the top of the existing spillway that not only adds weight to the structure, but helps prevent movement.

“You don’t want any movement because anytime you get movement, or water passing through, you create a risk with it washing away and eating away at some of those things,” explained Boyle. “So adding that thick concrete on top - that in addition to some repairs to the existing drainage system that’s beneath the spillway - that’ll help protect the structure.

After the concrete pour has wrapped, Boyle noted other maintenance includes the dam embankment road, improving movement monitoring of the spillway and the hillside beside it, then erosion prevention work will take place.

Safety signage and fencing around the site has also been accomplished as well as installing some large rocks at the inlet and outlet channels to provide increase erosion protection.

“Work has been scheduled to happen over the winter time here right now when the flows are at their lowest rate,” Boyle said.

Another concern was oxygen levels and the effect that the overall lower lake depth would have on fish populations. Aerators were placed in the lake before the ice took hold, and Tomlinson was pleased to report all systems are operating fine.

“The aerators are all working in the lake and the oxygen level is just hanging in there pretty good for the fish,” he confirmed.

In preparation for the work, the Water Security Agency lowered the reservoir by 30 cm to accommodate construction. A further decrease of 15 cm happened before freeze-up as another precautionary measure.

“This adjustment will reduce the necessity for mid-winter releases due to potential snowmelt, preventing the formation of thin ice in the downstream channel and on the reservoir,” said the WSA in a media advisory.

The public is still advised to stay of the ice, a recommendation clearly enforced by signage and fenced-off areas.

“You can put a dam on both sides of the structure and then you can do a lot of work in the middle of the winter where it’s all low. And then we’ll remove those in the spring and have flowing normally,” Boyle said. “We should be done in March with all the majority of the work and then it’ll take a couple months for the contractors to be mobilized, and they should be out of there in summer 2024. So everything is kind of going according to plan for the most part.”

Total cost of the project is an estimated $8.8 million upon completion.