2025 flood risk normal as Calgary’s overall flood resiliency reaches all-time high

Today marks the start of Calgary’s ‘flood season,’ the two months each year when river flooding is most likely to occur, and yet our city is heading into the 2025 season more flood-resilient than ever. Thanks to the recent completion of several key mitigation projects, Calgary has now achieved a 70 per cent reduction in flood risk exposure.

“What this really means is that we have eliminated 70 per cent of the amount of damages we can expect from flooding going forward,” says Frank Frigo, Manager of Environmental Management at The City. “Though there’s still more that needs to be done to protect communities that remain vulnerable to flooding, our city’s overall resilience has come a long way over the last 12 years.” 

The following are recently completed flood mitigation projects which are now contributing to Calgary’s flood resiliency.

Springbank Off-Stream Reservoir (SR1) – Calgary’s Elbow River communities are now protected from 2013-sized floods, thanks to the new Springbank Off-Stream Reservoir (SR1) located along the Elbow River, upstream of Calgary. SR1 will function as a dry reservoir, meaning it will only hold water when flood water is diverted into it. At 3,700 acres in size, it’s a massive network of flood mitigation infrastructure that includes a dam, diversion structure, canal and spillway.

It will work in tandem with the Glenmore Reservoir to significantly increase overall floodwater storage capacity on the Elbow River. The addition of SR1 will not only help protect thousands of residents that live and work along the Elbow River from a 2013-size flood, it will also protect critical public infrastructure such as roads, CTrain lines and drinking water and wastewater treatment plants from damage.

Built by the Government of Alberta, the $809 million project was cost-shared between the Province of Alberta ($641 million) and the federal government ($168 million).

Sunnyside Pump Station – Sunnyside has been prone to flooding, but a new pump station in the community can now direct excess surface water safely into the Bow River. This will reduce flooding in southeast Sunnyside and help prevent overland flooding on Memorial Drive, keeping it open for emergency services, Calgarians and City crews.

Bonnybrook Flood Barrier – The largest of Calgary’s three wastewater treatment plants, Bonnybrook was impacted due to flooding in 2013. Now, a new barrier on the east side of the plant will ensure critical treatment equipment and infrastructure is protected from flood damage and operation of the plant can continue during flood events. Most of the barrier was built by 2022, along with associated groundwater and stormwater enhancements that will further protect the plant. One section of the barrier remains to be completed.

With a combined cost of approximately $100 million, the Sunnyside Pump Station and Bonnybrook Flood Barrier mitigation projects were made possible thanks to contributions from all three levels of government, including funding from Infrastructure Canada’s New Building Canada Fund, Alberta’s Community Resiliency Program and The City’s Community Drainage Improvement (CDI) program.

Frigo says delivering on these projects was a real team effort. “An investment in Calgary's flood resilience is an investment in protecting Calgarians and our communities. We sincerely thank our federal and provincial partners for their valuable contributions and commitment to our resiliency program.” 

2025 flood risk outlook

Although Calgary is more prepared for flooding than ever, The City is always preparing for the risk.

This year’s mountain snowpack is below average. When that snowpack melts it increases the flow in the river, but we don’t usually see overbank flooding from snowmelt alone – river flooding is driven by large rainstorms. As such, Calgary’s chance of flooding this year is considered normal. 

Should a large rain system hit our region, River Engineering Leader Sandy Davis says The City is ready. “We’re ready to respond if we need to, to keep Calgarians safe and to protect critical infrastructure, vital community services, the environment and our economy. The City's annual flood preparations are complete and we’re now monitoring weather and river conditions 24/7.”

Davis adds, “As The City prepares for high river flow season, we are reminding Calgarians that flooding can’t be prevented entirely, so it’s important to take a few steps to be ready. Exercise caution around riverbanks in the spring, as the fast-moving water can cause erosion and destabilization.” 

If your property could be at risk of flooding, Davis has a few steps you can take to be ready for flood season. Here are her top three recommendations:

• Understand. Use our online interactive flood maps to know your home and community’s risk.
• Prepare. Take steps to reduce flood damage, keep your loved ones safe and be prepared if you need to evacuate quickly.
• Stay informed. River conditions can change quickly and with little warning. Visit calgary.ca/floodinfo for a quick snapshot of daily river conditions, sign up for alerts to stay informed and pay attention to any boating advisories issued by The City.

To help Calgarians be prepared, The City has flood preparation tools and resources available at calgary.ca/FloodInfo.