Concerned residents in southwest Calgary want the provincial government to change the design of a new bridge over the Elbow River.

Construction on the Southwest Ring Road project is underway. The $1.42 billion project will link Highway 8 with Highway 22X.

About two dozen residents have filed letters with the province's Environmental Appeals Board about the design.

The freeway will cross the Elbow River valley on an earth berm. There will be a 150-metre wide opening in the berm for the river to flow through into the Glenmore Reservoir just to the east.

Lakeview resident Allie Tulick is concerned what will happen to the berm when the Elbow floods.

"It really isn't good engineering practices to berm or dam a river into a small opening," said Tulick.

"If we have a significant flood event, there's a good chance that that berm will fail or top over and leak and that's going to, of course, ruin the Weaselhead, put wildlife at risk, flood homes upstream."

Lakeview resident Allie Tulick is concerned what will happen to the berm when the Elbow floods. (Scott Dippel/CBC)

Tulick is hoping the Environmental Appeals Board will halt construction so the design can be changed.

Open span bridge thought to be better option

Her preference is for an open span bridge which will allow water to pass under the freeway with few restrictions, just as it does through the area today.

Transportation Minister Brian Mason was asked during Question Period at the Legislature this week about the residents' concerns.

He said the government is confident the bridge design is sound and will pose no problems for the Glenmore Reservoir or the Glenmore Dam, even under flood levels, such as those seen in 2013.

"We've designed the bridge to have a 150-metre bridge span which provides additional hydraulic capacity and we've also designed the stormwater ponds so they can take more water in the event of a flood," said Mason.

As well, the province is planning to build the Springbank Off-stream Reservoir which Mason said will reduce floodwater levels before they reach the ring road and the Glenmore Reservoir.

Residents hope for quick resolution

Those answers don't minimize the concerns of residents.

Tulick said they hope the Environmental Appeals Board can deal with this issue quickly, before construction goes much further.

"They can recommend a new design and they can recommend what kind of design. That's my understanding of it," said Tulick.

"We're happy to work with them on that. I think that would be the best outcome, to just build a better bridge and get it right."

The province is on a tight timeframe to complete the Southwest Ring Road.

Under the terms of the agreement the province has with the Tsuut'ina Nation, the ring road must be completed by May 2022 or the land purchased by the province from the nation will revert back to the Tsuut'ina.

Currently, the province projects the freeway will be finished in the fall of 2021.