Province to decide future of Wawanesa dam

The province will soon make a decision about the future of a dam in Wawanesa, revolving around the need to ensure drinking water for the community of roughly 650.

The province is months from deciding between several design options for the dam, provincial project engineer Laura Robson told the Sun. Planners are weighing two options: rehabilitation of the dam, or replacement.

“We will be making a decision very soon,” said Robson. At an information session in Wawanesa in late August, she told the Sun, “This is the last step pretty much before we make the decision.”

Now staff need to pick from among several designs.

Five options were on the list, including repairing the dam, replacing it with a new structure, or building a new structure downstream. Each option comes with variables in cost, implications for public safety and the environment, ease of construction and maintenance.

The primary motivation for addressing the dam is to protect the community’s drinking water, Robson said. If the dam were to fail, it could jeopardize the Wawanesa reservoir upstream.

If all goes according to schedule, construction on the new dam is planned to start around the year 2027. How long it would take to complete is still up in the air.

According to the project engineer, the goal is for the new design to have a lifespan of roughly 50 years. Due to changing funding levels, this lifespan could vary.

The engagement session in late August aimed to fix any blind spots. Engineers pointed out that they were looking for any community feedback that might sway decision making.

One hypothetical example was if a fishing group told the province it gathered near the dam and would be impacted, officials could factor that in when considering different design options.

”We wanna hear from the community. We wanna make sure we don’t miss anything. We wanna learn how people interact with the reservoir,” Robson said, adding the province will return again, perhaps this winter, to share news about what design was chosen.

Robson said the dam has been on the province’s radar for monitoring and planning since 2017. It is now tested every year to ensure structural integrity while it awaits repairs.

The project to rehabilitate or replace the dam will be funded from tax dollars across the province of Manitoba.

Originally built on the Souris River in 1939, the existing dam was enlarged in 1951 and underwent major work in 1991. That 1991 rehabilitation involved strengthening the dam’s crest, its uppermost surface, after wear and tear caused it to operate at a lower level.

A 2013 dive inspection uncovered a 2.13-metre scour hole exposing a sheet wall made of metal and showing that those sheet piles had deteriorated.

Then, in September 2017, Manitoba Transportation and Infrastructure found a notch worn in the weir of one of the monoliths. A weir is a barrier that changes how water flows in a body of water.

At the same time, divers confirmed that the scour hole had grown in size and evidence of other damage and erosion, including signs of leakage around sites that had been repaired in 1991.

Several repairs have been done since 2011, including rehabilitating the north bank of the river, replacing riprap lost during flooding and installing steel guides and stoplogs as a temporary measure to repair a notch in the dam’s crest.

In 2019, the government hired a firm to complete a design for the renovation of the current dam, but it was deemed to be “undesirable due to concerns with anchoring the existing structure.”

» cmcdowell@brandonsun.com, with files from Colin Slark.

» X: @ConnorsCupful