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Media Releases

February 19, 2015

Winnipeggers invited to give input on a cost-effective strategy that will protect our rivers and lakes

Combined Sewer Overflow Master Plan Symposium will take place March 5

Released: 9:33 a.m.

Winnipeg, MB - The City of Winnipeg's first Combined Sewer Overflow Master Plan Symposium will take place on Thursday, March 5, 2015. Citizens are invited to learn more about combined sewer overflows (CSOs) and share their views on managing the effects of CSOs in an environmentally sound, sustainable and cost-effective manner.

As part of the requirements for the Environment Act Licence No. 3042, the City must submit to the Province:

  • a preliminary proposal evaluating CSO control limits by December 31, 2015, and
  • a final CSO Master Plan by December 31, 2017, for controlling CSOs to the defined limits.

The Symposium kicks off a multi-year public engagement program to help ensure that key choices and decisions made about CSOs meet all provincial licence requirements, and help protect the long-term health of our rivers and lakes.

Symposium details

Date: Thursday, March 5, 2015

Time: Registration at 5:00 p.m., Event 5:30 - 7:30 p.m.

Location: Millennium Library - Carol Shields Auditorium (2nd floor), 251 Donald St

Attendees will have an opportunity to hear various perspectives on managing the effects of CSOs from an expert speaker panel. There will also be small group breakout sessions.

About combined sewer overflows

A combined sewer is a single pipe system, built between the 1880s and 1960s, that collects wastewater from homes and businesses, and rainfall runoff and snow melt.

During dry weather, all flow in the combined sewers is carried to the sewage treatment plants.

During periods of heavy rain or snowmelt, the additional volume in combined sewers can exceed the capacity of the sewer system. During these occasions, combined sewer systems are designed to overflow and discharge the excess directly to the river without reaching the sewage treatment plant. On average, CSOs happen 22 times per year at each outfall. When a CSO occurs, it releases diluted sewage into the river, but it also helps prevent sewer backups that could result in serious damage to property.

While combined sewers aren’t ideal today, they were the standard all over the continent for decades. The goal for most cities is to reduce the number of CSOs. This is a significant and costly undertaking with many factors to consider.

Since the 1960s, cities, including Winnipeg, have been working to reduce these discharges.

More info


  • for an interactive animation about combined sewer overflows
  • for symposium details, including the expert speaker panel and agenda
  • for more details about combined sewer overflows
  • to join the conversation online
Last update: February 19, 2015