The City of Calgary is warning residents to stay off main roads and avoid driving unless absolutely necessary.

The advisory comes after a train derailment on Bonnybrook Bridge closed several of the city's main commuter roads Thursday morning.

Traffic congestion is making it difficult for emergency responders to conduct recovery clean-up efforts.

Employers are also being asked to tell employees to stay at home unless they are key to operations.

Service updates

In a press conference Thursday morning, city officials announced a number of service updates for local residents.

All Calgary landfills will be open on a temporary basis from 7:30 a.m. to 9 p.m. seven days a week.

Residents of flooded areas are advised to tell the landfill they are from a flooded area and disposal will be free.

Large disposal bins are also being placed in all affected communities.

Large items requiring disposal can be placed in front of the home — however, fridge and freezer doors must be removed or securely closed.

The city will also be doing courtesy tows of vehicles in affected residential areas.

There will be no charge to the vehicle owner for the tow, as officials want to keep streets cleared for flood recovery work.

Parking fees also resume Thursday for on-street and Calgary Parking Authority surface lots and parkades.

Officials are also reminding residents of Bowness, Sunnyside and Elbow Park to be cautious when flushing their toilets, as they may back up.

The city says it is working to restore full service.

Raw sewage released into Bow River

The City of Calgary may continue to discharge untreated sewage into the Bow River for several days.

The Bonnybrook Wastewater Treatment plant, which serves half of the city, was inundated with flood water and has only been able to screen out solid materials larger than six millimeters.

The director of water services, Dan Limacher, said that is only the first step in the treatment process which requires three steps, but he is not sure when they will all be in place.

"We think we're going to have the third stage, disinfection — we're going to have that process up sooner than the biological process and that could be as early the next couple of days."

Alberta Environment and Sustainable Resource Development is aware of the situation and a spokesperson said that given the contamination already in the river, this should not be a significant issue.

Renee Hackney said downstream communities are aware of the discharge as well.

"The drinking water facilities downstream are operating and drinking water is safe," said Hackney.

The discharge entering the Bow River is equal to one per cent of the river's current flow.