Sewage in Winnipeg rivers... again

A big rainstorm causes a lot of problems. And did we ever get one in Winnipeg this week!

Tuesday night saw over 120mm of rain fall in downtown Winnipeg. Trees were blown over and thousands were left without power. And Winnipeg got the least of it in the area.

While we see the flooded streets and basements, the power outages, and the damaged trees and gardens, one of the significant impacts of rainfall is on our rivers.

In Winnipeg, even the smallest rainfall can cause our storm sewer system to overload. In a large part of the city, any area built before 1970, when the storm sewers (the grates on the roadways etc) overload we get sewage spilled into our rivers. This week’s storm resulted in about 8.8 million litres of sewage flowing into Winnipeg’s rivers.

This happens because Winnipeg has combined sewers across the older parts of the city. When the areas were built, they only installed one sewer line, into which both household sewage and street runoff flows into. In a rainstorm, these combined sewer lines can fill up and overflow into the river.

While 8 million litres of sewage spilled in the Tuesday night storm can seem like a lot, it pales compared to the average of about 11 BILLION litres of sewage that gets spilled into our rivers each year.

In this post from 2024 I went into the details of the challenge of combined sewer overflow (CSO) and the city’s plans for addressing it. Currently about 31% of Winnipeg has combined sewers.

Climate Change means that we are going to get more storms where 5 or 6 inches of rain gets dumped on the city in one storm, leading to millions of litres of sewage being spilled into the rivers.

For the whole poop read Water, Water, Everywhere.

We need to begin to look at all the challenges we face and seek holistic solutions. Our approach of throwing more of the same at things is not getting us anywhere.

brian