At the final meeting updating the Bearspaw South Feeder Main repairs on Jan. 16, Calgary Mayor Jeromy Farkas said installing a replacement pipe was a priority for the city; something that would normally take upwards of two years to complete but something he wanted done in one year.
At city council’s meeting on Tuesday, Infrastructure Services General Manager Michael Thompson said the process has begun, with a sole-source contract being awarded to Ward & Burke Microtunnelling Ltd. and Graham Construction.
It is an unprecedented move by the city, which usually puts such projects out for bid.
Since the break on Dec. 30, city officials have repeatedly said repairs to the feeder main would not guarantee it wouldn’t break again, one reason for not putting the work out for bid, said Thompson.
“We evaluated the risks that we were facing as a community and made the decision to cancel the existing procurement and to award it directly to a contractor who could start immediately,” he told council. “We did that on Friday and that team started on Friday.”
Crews will be installing a pipe parallel to the existing pipe, using micro-tunnelling, a specialized, trench-less technique used to install large-diameter pipe underground, especially when there are major obstacles at ground level, which in this case include 16 Ave. NW , the Bow River, Sarcee Tr. and the CPKC rail line.
"This construction technique has been used by the water utility for other large diameter pipes, including the Inglewood Sanitary Trunk crossing of the Bow River and Nose Creek Sanitary trunk adjacent to Deerfoot Trail," said the city in a statement.
According to the statement, “While some surface work will be required, work can happen at targeted locations instead of along the entire corridor. Micro-tunnelling is the best practical option for this stretch as the buried infrastructure we need to reach can be best accessed in this targeted manner instead of needing open trenches along the corridor.”
“It is expected that the feeder main will continue to remain in service, except for short durations when the new pipe needs to be tied into the existing feeder main.”
The work will be done in two stages, with the first beginning at the Shaganappi pump station, just west of Point McKay and on to 73 St. N.W. on the west of the Bow River. The second stage will run from 73 St. to 89 St. N.W., with a potential extension to the Bearspaw Water Treatment Plant.
The exact cost of the replacement pipe work has yet to be made public, however city officials estimate the cost at approximately $200 million and possibly higher due to the accelerated timeline.
Funding for the first phase is being drawn from the water infrastructure budget $1.1 billion, which was previously approved by council for water projects through 2031.
It is expected that city administration will at some point return to council for additional funding for later phases and reinforcement work.