Last Friday, we marked all the locations where pipe repairs will occur in pink. We’ve also been in touch with residents to explain what the other colours of road markings mean. These additional markings help us identify and protect existing utilities during construction.
Starting today, crews will begin sawing into sections of pavement on 33 Avenue N.W. This is the first step in the excavation process to expose the feeder main. On August 26, the actual removal of road sections will begin.
Next, we are working on safety measures, including where to place fencing and how to ensure residents can access their homes safely as we know that many don’t have a laneway behind them. At the same time, we are planning for where the road closures and detours will be to provide space for all our equipment and other logistics.
We’re also planning for waste and recycling services, emergency responses and contingency plans for any unexpected water service disruptions. A pop-up session will be organized this week for residents directly affected by the construction, with details to be shared soon.
Resident impact
Of the 21 pipe segments being repaired, 13 are located along 33 Avenue N.W., meaning residents here will not only experience the city-wide water restrictions but also the direct effects of construction work on the Bearspaw South Feeder Main. While this work is essential, we understand that many Calgarians are concerned about how construction along 33 Avenue N.W. might impact their properties.
Our teams are working hard to finalize construction plans and assess the impact on properties and street access along 33 Avenue N.W. Typically, projects like this involve three to six months of planning, but we are compressing this process into two weeks to address concerns as quickly as possible.
We have been in communication with the most affected property owners to discuss how the construction might impact their landscaping and driveways and the restoration work we are committed to doing once the work is complete. We will continue to share updates as soon as new information becomes available.
Business impact
We’ve been working on plans to minimize the impact to the businesses in the Montgomery Business Improvement Area along 16th Avenue N.W. and for 33 Avenue N.W. This time, we’re able to apply lessons learned from earlier construction phases to improve detours and access. Based on our initial assessment, we don’t expect to close any driveways, and customers will still have access to businesses in these areas. More detailed plans will be shared later this week.
Parkdale clarification
Last week we mentioned that there would be no further water restrictions to Calgarians during the pipe repairs on Parkdale Boulevard N.W. between 26 and 27 Street N.W. Upon review, it is still too early in the process to guarantee there won’t be any additional water restrictions. While this next phase of work won’t require shutting down the feeder main, our teams are working on plans to minimize disruptions and we’ll provide more information once those plans are finalized.
How Calgary’s water distribution system works
Our water distribution system is a complex network designed to provide clean, safe drinking water to Calgarians. We have two primary water sources: the Elbow River and the Bow River. Water from these rivers is not safe to drink immediately, so it is sent to one of our two water treatment plants to be treated.
The Bearspaw Water Treatment Plant, located on the Bow River, is the largest and can treat between 500 to 550 million liters per day (MLD). The Glenmore Water Treatment Plant, located on the Elbow River at the Glenmore Reservoir, can treat between 350 to 400 MLD.
After the water is treated, it flows through large pipes called feeder mains, which are powered by pump stations. These pipes carry the treated water to underground storage reservoirs. Unlike the Glenmore Reservoir, which holds untreated water, these underground reservoirs store clean, treated water, ready for distribution to Calgarians.
The underground storage reservoirs have the capacity to hold about one day’s worth of water supply for Calgary, with additional reserves for emergencies, such as firefighting. This system ensures that Calgarians always have access to safe drinking water.
When the Bearspaw South Feeder Main is out of service for repairs, the Bearspaw Water Treatment Plant can only contribute around 100-130 MLD to the system, which is a significant reduction from its normal output. The Glenmore Water Treatment Plant is not designed to meet the full demand of the city on its own.
On a typical summer day, for example, Calgary’s water demand ranges from 650 MLD to as much as 800 MLD during hot weather. With the Bearspaw South Feeder Main out of service for repairs, we cannot meet this level of demand.
Our safe water production limit during the repair period is 450 MLD, which accounts for the Glenmore Water Treatment Plant operating at full capacity and the reduced output from the Bearspaw Water Treatment Plant. We must keep our water usage within this limit to ensure there’s enough water for essential services like hospitals and firefighting.
If we don’t reduce our water usage and demand exceeds what the system can produce, the underground storage reservoirs will eventually run dry, leading to a drop in water pressure. Adequate water pressure is crucial for keeping the water safe. Without it, contaminants can enter the system, potentially resulting in a boil water advisory for areas served by the depleted underground reservoir.
A city-wide boil advisory is possible if multiple underground reservoirs are depleted. Refilling them wouldn’t immediately solve the problem, as the system would need to be flushed to remove any contaminants. This process requires a large amount of treated water. At this time of year, flows on the Elbow River naturally start to decrease and we rely on water stored in the Glenmore Reservoir to help us get through winter. If a boil water advisory were to occur, it could last several months until enough water is available in the spring to safely flush and clean the system.
This scenario highlights the importance of Calgarians working together to keep water usage within the safe production limit during the repair period.
We know how challenging the water restrictions have been for everyone—residents, businesses, industries and our regional partners, especially since we’ve been under some level of restrictions since June 5. We appreciate your understanding and support as we undertake these critical repairs to the Bearspaw South Feeder Main.
