The lower deck of the Centre Street bridge was shut down Friday morning to allow crews to begin flood mitigation work.
The road in and out of downtown will be closed to all traffic until Sept. 11, 2018.
The city is adding concrete foundations with anchors at either end of the bridge to support an aluminum “stop-log gate.”
According to the city of Calgary’s website, the foundations will not be noticeable to motorists under normal conditions. However should water levels rise in the Bow River and threaten to override the bridge, the stop-logs can be added to help block the flood water.
“The aluminum stop-log components will be stored on site in sheds. During a flood event, city staff will install the posts and aluminum stop-logs to erect the two temporary gates and block the flood water.”
This infrastructure is similar to what has been added to the bridge to St. George’s Island to protect the Calgary Zoo, and downtown west Eau Claire.
Alternate routes into downtown during construction include the 10th Street bridge or the 4th and 5th Avenue flyovers.
Rehabilitation work is currently being done on the Reconciliation Bridge, so that road has been reduced by one lane until Sept. 15.
The flood mitigation work is partially funded by the provincial government’s Alberta Community Resilience Program.
The Centre Street bridge runs between Memorial Drive in the north to Riverfront Avenue in the south.
With files from Doug Vaessen