$50M Sunnyside flood barrier project digs in

Ground has been broken on a massive project to keep Bow River flooding on the south side of Memorial Drive, away from the thousands of residents in Hillhurst and Sunnyside, but costs include the loss of hundreds of trees.

The Sunnyside flood barrier — a 2.4-kilometre project costing an estimated $50 million — is designed to mitigate flood damage, last seen in 2013 when some communities were devastated. That June 2013 flood cost $6 billion in property damage and financial losses in southern Alberta.

"Homes and businesses were submerged and a great emotional toll was taken on residents and all of Calgary," Mayor Jyoti Gondek told reporters Thursday at a groundbreaking.

"As we picked up the pieces and we rebuilt these communities, it was crystal clear that we needed to make a strong commitment to upgrading our infrastructure to prevent this level of devastation from ever happening again."

An artist rendering of the Sunnyside flood barrier, where groundbreaking took place Thursday. (City of Calgary)

Calgary was among the hardest hit, with more than 25 communities experiencing evacuations, affecting 110,000 people. Sixteen LRT stations were closed, 50 transit buses pulled from the road, and tens of thousands of residents were left without power.

"This barrier will minimize the need for individual response and provide security in a way that is proactive and protects us long into the future," Gondek said.

But the 2013 flood was 11 years ago, what took so long?

"The first few years post-flood, we were doing the flood-mitigation measures assessment to determine the best flood-mitigation options for Calgary," project manager Amy Stansky explained.

An artist rendering of one section of the Sunnyside flood barrier. (City of Calgary)

"We went through a couple of different rounds of project evolution to ensure this could meet the community's needs."

While the city says removing trees is always a last resort, the project will require 337 trees to come down. Twenty-two were removed this year. The rest are slated for 2025.

The project has been designated a one-in-100-year option, referring to the rarity of the 2013 flood. It's estimated to take about two years to complete.