Winnipeg, December 22, 2009 – On Monday, December 21, 2009, City of Winnipeg crews confirmed that a portion of the sewer under St. John’s Avenue between Powers and Salter Streets had collapsed, allowing only a portion of the flow to get through the sewer. The excess wastewater was forced into a storm relief sewer along Mountain Avenue, and then flowed into the Red River near St. John’s Park.

Crews closed the gate on the sewer at the edge of the riverbank and wastewater is no longer flowing to the river.  Instead, wastewater from this sewer is being stored in the relief sewer until it overflows into an interceptor sewer, and then to the North End wastewater treatment plant.

Work is underway to open up the collapsed sewer on a temporary basis and restore enough flow so that the wastewater can resume its normal path to the treatment plant. An assessment of the extent of the damage is expected later this week. A permanent repair will be performed early in the New Year. Normal winter flow can be easily handled in this manner.

Starting Friday, December 11, 2009, crews noticed open water along the shore of the Red River at the land drainage outfall of St. John’s Park, and began investigating.

This sewer was last inspected internally with a video camera in 2003 and was rated in fair to good condition, which means there aren’t any deformities, and that a collapse is unlikely. This is the original sewer installed in this area, likely in the early 1900s. It is a large egg-shaped combined sewer, 1375 millimetres (4.5 feet) at its widest point and 1825 millimetres (6 feet) high. The City’s Water and Waste Department is investigating the cause of the collapse.

The affected area has been barricaded to protect motorists and pedestrians while repair work is underway.

There have been no reports of homes affected with basement flooding. City crews will be monitoring the situation until the temporary repair is in place.

Manitoba Conservation and Environment Canada have been notified of the situation.