Flood risk for Calgary remains significant

City officials warn another flood like 2013 would cause significant damage in Calgary and that threat will remain until a major new dam is built upstream on the Bow River.

City says full protection on Bow River not possible until major project built upstream

In June 2013, a massive storm dumped record amounts of rain on southern Alberta, leading to devastating flooding in Calgary and other communities throughout the region. (Andy Clark/Reuters)

City officials say there's still a significant risk of damage to parts of Calgary if there's another major flood — and that risk will remain until a new dam is built upstream of the city on the Bow River.

Flood protection projects have been worked on ever since the 2013 disaster hit Calgary.

A council committee heard Wednesday that once a major renovation of the Glenmore Dam is completed and the province finishes the Springbank off-stream reservoir, there shouldn't be any future flooding along the Elbow River in Calgary.

However, the Bow River is a different story. And could be for a number of years to come.

This image shows the potential of the impact of the 2013 flood on Calgary's inner city without any mitigation, left, the flooded area in 2013, centre, and the impacts of full mitigation on the Bow and Elbow Rivers of a 2013-sized flood, right. (City of Calgary)

There are several flood barrier projects planned to protect specific communities along the Bow.

Even when they are combined with operations to lower spring water levels on the Ghost Reservoir, officials say Calgary still won't be protected against another flood the size of the 2013 event.

New dam could help protect city

Frank Frigo with the city's water resources department said getting a new reservoir on the Bow is the key to flood protection.

"More than 40 or 50 per cent of the overall resilience would rely on the upstream reservoir," said Frigo.

The Bow River Working Group, which studied flood mitigation on the river, submitted its report to the provincial government last year.

The Ghost Reservoir Dam currently acts as the largest flood-mitigation measure upstream on the Bow River in spring. (Jeff McIntosh/The Canadian Press)

It identified two key sites for a new dam upstream of Calgary.

Frigo said one is the Glenbow site, which is just north of the Springbank Airport. 

The other is the Morley site, which includes land belonging to the Stoney Nakoda First Nation.

It is also possible that the Ghost Dam could be expanded to give it greater capacity.

Protection could be years away

The Bow River Working Group estimated such a project would take a decade to complete.

"Of course, very significant engineering, environmental and water management analysis would have to be done to ensure a piece of infrastructure like this could be configured appropriately," said Frigo. 

What that means is that Calgary is still at significant risk of damage in the event of another flood.

Frigo said that if there were to be another flood event the size of 2013, only about one-third of the potential damage could be prevented with the measures taken so far.

Councillor unhappy with lack of progress

Coun. Druh Farrell says she's frustrated at the slow progress that has been made on the flood mitigation file.

Council's committee on utilities and corporate services passed a motion Wednesday, calling on the province to reconvene the Bow River Working Group to help direct mitigation efforts.

"I'm still frustrated at the lack of co-ordination between the city and the province on an overall strategy. Where do we want to be in a certain number of years, and we seem to be missing that part of the conversation," said Farrell.

The provincial government recently agreed to help fund a new downtown flood barrier, which will extend from the West Eau Claire barrier to Reconciliation Bridge.

However, there are three other projects that the city has identified on the Bow, including the Bowness, Sunnyside and Pearce Estate/Inglewood barriers.

A map showing where a proposed flood wall will be built in Bowness. (City of Calgary)

Downtown could soon be safe from floods

Coun. Ward Sutherland told reporters he'd like to see the city reach into cash already set aside from its fiscal stability reserve fund and get going with those projects. 

He said it could then try to recover its costs from the province later.

"We have the money put aside anyways. It's been committed, and if we have to take a look at it to finish some projects, then maybe we need to dip into that. It doesn't affect taxes or anything," said Sutherland.

If there was another flood like the one-in-70-year event that hit Calgary in 2013, at least the damage downtown would not be as bad today as it was five years ago. 

Frigo said that once short-term protection projects like the new flood barrier downtown is completed and the Elbow River mitigation projects are done, Calgary's core will be protected to a one-in-200-year flood level.