CSO Master Plan Phase 1 Public Meetings Questions & Responses
September 14 and 15 Questions
Are basement backups caused by combined sewer systems?
- Yes, basement backups can be caused by high levels in both the combined and separate sewer systems if the home/business is not protected by a backwater valve and sump pump system. The City of Winnipeg and the Province of Manitoba have a joint program to assist residential homeowners subsidize the cost of installing a backwater valve and sump pump system. Further information can be found here.
Is the reduction of basement backups factored into the cost/benefit analysis for the CSO plans?
- Yes, it is factored into each of the CSO options.
The presentation refers to Wastewater Systems Effluent regulations and states that ammonia is not a factor due to dilution—has the City sampled for ammonia?
- Yes we have sampled for ammonia as part of the CSO water quality monitoring program that we have undertaken over the last two summers.
Are water samples taken at the outfall before it reaches the river?
- Yes, water samples were taken upstream, in the outfall, prior to the overflow discharging to the river at 8 locations. We also take samples in the river.
What causes CSO overflows during the winter?
- Many factors can cause dry weather overflows during the winter, such as rapid snow melt, water main breaks or a high water table leading to infiltration.
Do any of the CSO options include in-line storage?
- All the proposed options will have some component of in-line storage depending on the level of storage required.
What will the zero overflow option consist of? Would it be dedicated transport tunnels?
- The zero overflow option will consist of tunnels and controlled pumping.
- Dedicated tunnels can span multiple combined sewer districts to store the storm water and pump to the treatment plant once the storm event peaks have passed.
Do the CSO options consider green technologies like storm water management? What would this look like?
- As part of all the options, green technologies will be incorporated in some form.
- Green technologies could include but not limited to rain gardens, green streets, bioswales, etc.
Do the CSO options proposed have the capacity to deal with the impacts of climate change and extreme weather?
- All options will be impacted by climate change. The additional storage volume required will depend on the recommended option, which will be designed at a later stage.
Can phosphorus be managed through the CSO Master Plan (CSO MP)?
- The CSO MP may not be the best way to address the phosphorus issue. Phosphorus in the captured flow will be treated at the sewage treatment plants once the nutrient upgrades are complete.
How does the City plan to manage growth in the core areas, given that most combined sewers are found there?
- The CSO Licence does not allow for increased CSOs due to further development.
How many overflows occur in the Cockburn CS district? Is the City in compliance by not adding additional CSOs?
- The Cockburn district had 18 CSO events in 2014.
- There is currently separation work being undertaken in Cockburn.
- Any new development is restricted to pre-development runoff flows.
Is the plan to install a two-pipe system (complete separation)? Is it difficult to construct?
- Until we have a control limit set, we do not know how much of the system will be a complete separation (two-pipe system).
- Complete separation the most costly option but it can be done with time and coordination.
What would the impact be on sewer/water utility bills if Option 5 (complete separation) were spread out over 60 years?
- The impact would be less, but inflation would need to be factored in. The total costs would be more for this scenario. Further information regarding implementation time can be found here.
What time period was used to calculate the "average rainfall?" Does this include climate change?
- About 30 years of data was used to calculate the "average rainfall."
- Climate change will need to be factored into the design and will be done at a later stage.
When work begins on limiting CSOs, will the entire 1000 KM of sewers be affected?
- No, only parts of the 1000KM of pipe will be affected as there has already been previous work done in combined sewer areas.
What control limit would the Ness/Route 90 sewer work fall under? How many years will that take?
- That work is under the current program – see the information displayed on the "Current Approach to CSOs" storyboard.
- This program is ongoing and is projected to be completed in about 10 years.
Why do the storyboards have an Option 0 (current approach), considering MB Conservation and Water Stewardship provided the City a Licence to explore different CSO management options?
- The Province issued the Environment Act Licence No. 3042, which pertains to the management of CSOs.
- There are five proposed CSO Control Limit Options and option zero ("Current Approach to CSO") storyboard is shown as a baseline to disclose the work the City is currently undertaking.
Do you know how much volume is discharged into the rivers when you average 22 overflows a year?
- About 1% of the total annual sewage generated is lost to overflows.
When overflows discharge to the rivers, has nitrogen or phosphorus been removed? What is the impact on our waterways?
- No, nitrogen and phosphorus are not captured when CSOs occur.
- Nitrogen and phosphorus amount in CSOs is a small component of the total nutrient loadings to Lake Winnipeg. We want to do our part in reducing those numbers but it is also our responsibility to inform the public that eliminating CSOs will have very little impact on the health of Lake Winnipeg.
Last updated: January 31, 2019