Council approves contract to replace damaged storm sewer
A damaged storm sewer along 13th Avenue in Swift Current will be replaced and redesigned to reduce future erosion around the discharge area into the Swift Current Creek.
Council members approved the storm sewer and outfall replacement contract during a regular council meeting, Oct. 31.
City General Manager of Infrastructure and Operations Mitch Minken told the meeting the urban stormwater system within Swift Current has approximately 67 outfall or discharge locations along the Swift Current Creek.
“These structures dissipate and slow water as it exits the underground pipe system and enters the waterway,” he explained. “Outfall failures have the potential to cause widespread erosion to the creekbank, creating a risk for further damage to the storm system and other infrastructure.”
This broken storm sewer pipe, which resulted in significant erosion, was discovered during inspections of the stormwater system east of 13th Avenue NE and North Hill Drive.
He noted the location of the storm outfall probably contributed to the severity of the erosion around the outfall area.
“The existing storm main attached to the outfall is very steep, creating high flow velocities that likely caused the erosion under the outfall and the storm main to deteriorate,” he said. “The outfall is also in close proximity to the creek, exposing the structure itself to damaging ice flows during spring runoff.”
A new design for the 13th Avenue storm outfall was done in-house by City staff. The goal is to decrease the velocity of the stormwater by reducing the slope of the incoming pipe.
“The outfall will be relocated further up the bank with a concrete matting spillway to the creek edge to remove the outfall from the path of damaging ice that occurs during springtime,” he said.
The work to be carried out during this project will include the removal and replacement of the damaged storm pipe and concrete outfall structure; the construction of an armoured spillway with concrete matting, and the installation of a new manhole.
There is significant erosion around the damaged stormwater pipe at the 13th Avenue outfall structure.
The City received only one submission in response to a request for proposals from local contractor Knudsen Excavating Ltd. The cost of the work was higher than expected, which was due to a requirement to complete the project in 2022 under a tight work schedule that potentially included construction activity during winter conditions.
The City therefore negotiated the terms of the project with the contractor to lower the cost by allowing work to take place in the spring of 2023. As a result, the contract price of $138,745.84 (10 per cent contingency and PST included, GST excluded) is nearly $41,000 less than the original submission.
The largest portion of the project cost will be funded from the City’s 2022 capital budget, but an amount of $32,245.84 will be reallocated from the 2021 carryover budget.
“From time to time we have carryover amounts,” Minken said. “Usually, they are committed. In this case, the 2021 budget was committed for work on the 6th Avenue realigning project, which is running into some problems and we need to re-evaluate where we’re going. So that’s why this money is becoming available.”