Further repairs planned after 16 new problem areas were discovered in the main line that burst on June 5
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Calgary residents will again be subject to Level 4 water restrictions for a period of nearly four weeks in late August, city officials said Wednesday, after data from an engineering analysis revealed 16 more vulnerabilities along Bearspaw’s recently repaired southern main.
At the same time, Calgary residents are also being asked to limit their non-essential indoor water use.
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Mayor Jyoti Gondek said the high-tech pipe diver the city sent in July to examine the interior of the nearly 11-kilometer-long main supply line identified another 16 sections that needed urgent repairs – similar to the five “hotspots” identified in late June.
“I know this is not the news we all wanted to hear,” she said during an afternoon press conference at City Hall. “At the same time, I am grateful that we have this important information that will allow us to act in a way that will protect our water system from potential breaches.”
Although these parts of the pipeline are not in immediate danger of rupture, Gondek said they are still showing signs of weakness. To avoid another catastrophic failure, the city has decided to complete the repair work this month.
“This is not an emergency situation like in June,” she said. “It is planned maintenance based on the results of the pipe diver.”
The majority of the repair work will be done along a section of 33rd Avenue NW and Parkdale Boulevard. The closures will primarily impact residents and businesses in Bowness and Montgomery during the duration of the planned work, Gondek added.
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The news comes more than two months after the June 5 water main rupture that cut off the city’s water supply and led to a days-long boil water advisory in Bowness, more than four weeks of strict water restrictions and a citywide fire ban.
Gondek said the same restrictions on outdoor watering will be in place starting Aug. 26. Extensive repair work on the main supply line will begin two days later and will continue around the clock. The work is expected to be completed Sept. 23.
During this time, Calgary and surrounding areas that use the city’s reclaimed water (including Airdrie, Chestermere, Strathmore and Tsuu’tina Nation) will be more reliant on the Glenmore Water Treatment Plant to replenish local supplies.
That means a return to Stage 4 water restrictions, which prohibit the use of sprinklers and garden hoses. The city will also ask residents to again reduce their indoor water use by 25 percent while Bearspaw’s south main is shut off.
The planned repairs would minimize the risk of another unexpected break during the winter months, said Michael Thompson, general manager of city infrastructure services.
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He said this is because the Bow and Elbow rivers (Calgary’s raw water sources) have higher flow rates in the spring and summer due to rainfall and snowmelt in the mountains. In the late fall and winter, Calgary relies more heavily on the Glenmore Reservoir, which acts as the city’s water bank, drawing from the spring when Elbow River flows are lower.
“We need to make sure there is enough water in the riparian area to last until spring,” Thompson said.
“We must act now to ensure that the urgently needed repairs can be completed in time for the river to refill Glenmore Reservoir for the winter.”
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Instead of cutting out the weakened pipe sections and replacing them with new ones (like the piece San Diego delivered to Calgary in June), Thompson said crews will use a different reinforcement method that involves Structural reinforcement of existing parts with reinforcing steel and concrete.
The work includes exposing the pipe through excavation, constructing an external steel cage, pouring reinforced concrete and then backfilling the excavation.
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He said the city will use lessons learned from the June restrictions to minimize disruption to citizens, but acknowledged that the reduced water supply “will not be enough to meet normal needs” during one of Calgary’s hottest months.
While some businesses remained closed in June due to the lockdown, that will not be the case this time, Thompson said. There will also be no boil water advisory or water trucks.
“We will also not close indoor swimming pools, either in hotels or leisure centers, and we will not close arenas,” he said.
In order to speed up the repair process and keep the impact on the population as minimal as possible, work on the line is being carried out around the clock, Gondek stressed.
One of the few positive findings from the pipe diver’s analysis, Gondek said, is that the upcoming repairs are not an emergency measure like in June and that Calgary residents have nearly three weeks to prepare for the upcoming restrictions.
“There is a lot to digest and that is why I wanted to get this information out to the people of Calgary as early as possible,” she said.
“The fact that these repairs are part of planned maintenance puts us in a much better situation than the crisis response we had to undertake in June.”
Also on Wednesday, Thompson said the total cost of repairs and remediation to date is approximately $20 million to $25 million, noting that this does not include the work that is still to be done and does not take into account the lost revenue for city services caused by the rupture.
The city will fund all repairs to the main line from the water supply reserve, which Thompson said will total nearly $43 million by the end of 2023.
Check out the City of Calgary’s update here:
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