Shawnee’s aging stormwater infrastructure is becoming a widespread problem, with the city needing as much as $140 million over the next 10 years to repair or replace drainage pipes that are on the brink of failure.
Public works staff demonstrated this need in a presentation to the Shawnee council in early April. Staff have doubled efforts in the past two years to video inspect pipeline and get a full grasp on the scope of the city’s pipeline network. What they’ve found: More than 220 pipes are expected to fail in the next three to five years, costing anywhere between $11.2 and $14 million.
City staff estimated that about 57 percent of stormwater pipes have exceeded their life cycle expectancy. Repairs are expected to outpace the funds of roughly $1.6 million generated each year from the stormwater utility fee.
‘We’ve got to prioritize’
Doug Whitacre, Shawnee public works director, said staff have been closely looking at the aging pipeline issue for the past five years. Shortly after that, the city doubled the annual stormwater utility fee to $72 per lot in 2017.
The fee generates about $3.5 million each year that is earmarked for stormwater improvement projects. In total, Shawnee budgets about $4.7 million for stormwater improvements, supplemented by an additional $750,000 from the city’s general fund. Most of that is used to cover other stormwater work, such as cleaning manholes, street sweeping and maintenance.
“We’ve got to prioritize,” he said. “Yes, we’ve got a need. It’s going to be overwhelming. We’ve got to figure out how to address it, but in all my years of experience, I don’t know of any place I’ve been that I had unlimited funds.
“You have to manage it, prioritize it, and address those areas that you need to. With the data that we’re using, we’re trying to manage the assets and prioritize what needs to be repaired and spend the funds that I have in those places.”
Whitacre said that when pipes collapse, sinkholes can occur and roads above these pipes can collapse. As such, their key focus has been to inspect pipelines under major roadways.
“If there’s a pipe that goes under someone’s backyard, versus a pipe that goes under Shawnee Mission Parkway, I’m going to worry about Shawnee Mission Parkway way before I worry about somebody’s backyard,” Whitacre said, citing the risk for sinkholes on the corridors going through Shawnee. “When it finally fails and collapses, it will drop down, which then drops the roadway down.”
About 56 percent or 101.5 miles of the city’s pipelines are made of corrugated metal, which rusts and corrodes more easily than the concrete pipeline the city now uses. Concrete pipes last an average of 50 years, while corrugated metal pipelines may only last about 30 years. Sand, dirt, salt and other elements break down the steel, corrugated metal, corroding the bottom of the pipe and ultimately causing failure. The city’s hilly terrain also puts pipelines on a grade, causing more abrasion.
A completely failed pipe is replaced with concrete pipe, whereas an aging pipe that is still structurally sound may only need to be sealed. As such, plans for stormwater repair and replacement are listed in the city’s 10-year capital improvement program that begins next year. The Shawnee council on May 28 voted 7-1 to approve the program, with Councilmember Eric Jenkins voting in dissent.
In that program, staff added six other stormwater projects to be completed this year — a bond issue will cover about $8 million in costs for these projects:
- Seven Hills Lake culvert replacement
- Johnson Drive & Widmer culvert repair and lining
- Renner Road stormwater pipe under Shawnee Mission Parkway
- 52nd & Woodland Drive storm drainage improvements
- Quivira Drive & Park Street culvert replacement
- Blackfish Parkway & Hauser culvert replacement
Whitacre said the city has completed about 60 percent of video inspections of the city’s 185 miles of pipeline; he expects inspection of the city’s entire pipeline system to be complete in the next three years. He noted that Shawnee is not alone in this situation; cities across the country are facing aging infrastructure issues.
“We’ve got to work at it over time,” he said, adding that there’s only so much in the city budget earmarked for stormwater repairs. He added that no funds from other departments such as parks and recreation — including for a proposed community center that Shawnee voters voted down last month — could be used for public works projects. “Voting the community center down did not give me more money.”