Sustainable Built Environments

The number of combined sewer overflow locations across the country within how many municipalities, and the volume of untreated sewage coming from these sources (data shown is cubic metres of untreated sewage).


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Story Behind the Curve

What are the stories that help us understand why so much untreated sewage is entering our waterways? OLW Network members who work on this impact measure shared the causes they believe are at work, both negatively and positively, with respect to the number of combined sewer overflows in Canada and the resultant untreated sewage:

  • Population growth in some regions
  • Increased rainfall in some regions (e.g. the Great Lakes)
  • CSO/sewage volumes being measured for the first time in many places
  • Substitution of provincial rules for federal
  • Increase in the number of recreational water users & changing expectations for water
  • Legal & policy decisions favouring sewage information sharing (e.g. alerts)
  • Improvements in US cities showing the way along with more monitoring and modelling in US
  • Legal consequences, funding, transparent data & political will

Who are the partners that can support us in doing better against this impact measure? The following are many of the partners who have a role to play (although the list is not exhaustive):

Indigenous partners; watershed entities (e.g. Conservation Authorities); Non-profit groups (such as Swim Drink Fish, EcoJustice, Green Communities Canada, etc); Groups like the Federation of Canadian Municipalities, Tech sector, Governments (Fed/Prov/Terr/Indigenous)

Ranking the Actions

Based on the stories behind the curve and the partners who have a role in supporting us doing better, a number of potential actions were brainstormed and then ranked based on two criteria:

  1. Leverage (L): This is the most important criterion. How much difference will the action make on our impact measure? Will this actually help turn the curve? E.g. handing out pamphlets at a community event isn’t necessarily a bad idea, but it's probably low leverage.
  2. Reach (R): That is, “is it within our reach”? Is it feasible and affordable? Can it actually be done and when? No-cost / low-cost actions rank highly here. Action that require new significant resources rank lower. Is there a clear lead person (higher), or does nobody want to take it on (lower)?

The top three actions brainstormed are as follows (in order of how they were ranked)

  • Advocate for real time public reporting in an open format tht is not a PDF (e.g. Wastewater Systems Effluent Regulations data)
  • Reframe the narrative around CSOs (i.e. stories on the feasibility of fixing the problem, champion the positive examples, etc)
  • Initiative to have the federal government make a commitment to elimate CSOs across Canada

Other actions that were brainstormed but were ranked lower (and thus will not be pursued given the group felt that either the action was low leverage or out of their reach):

  • Add flow monitors to pipes of all CSOs
  • Earmarked federal infrastructure money
  • Template municipal by-laws

There is a great deal of action being taken by OLW Network members to tackle the amount of CSOs and untreated sewage in Canada. Efforts to push for transparent, real time reporting of CSO events are well underway as told in this OLW impact story. In addition, to support municipalities - each with their own unique circumstances - to solve their challenges with CSOs, a comprehensive, bilingual resource called Tacking Combined Sewer Overflows: A Toolkit for Community Action has been developed.

If you are interested in being connected to the OLW Network members who are taking action on this impact measure, please contact us and we can connect you to those groups!

Scorecard Result Container Indicator Measure Action Actual Value Target Value Tag S R I P PM A m/d/yy m/d/yyyy