Corrugated metal storm sewer pipes — installed years ago to save on construction costs — have become a $35 million problem in Leawood.
The city council informally decided Monday to include replacement and repair of about 20 miles of those rusting and collapsing pipes in its long-range budget. That could mean an eventual mill levy increase and a lot of torn up yards a few years from now, if the council goes ahead with the plan.
The council members’ consensus at a committee work session Monday was to proceed with a seven-year plan that would take care of about 15,000 feet of pipe per year. The sewer work would add three mills to the city’s property tax eventually. That would amount to an increase of as much as $175 per year on a $500,000 home, said City Administrator Scott Lambers.
The earliest construction could begin would be 2016, if the full council gives its final approval.
The pipes in question are about 25 to 30 years old and of varying sizes, said Joe Johnson, public works director. They make up about 14 percent of the city’s storm sewer system, and they do not age well, he said.
Johnson showed videos of pipes that had rusted out at the bottom, allowing water to escape. In some cases, boring for utility lines, street lights and fence posts have partially collapsed the pipes and limited their capacity, Johnson said.
Most of the steel pipes are concentrated in the area between 119th and 135th streets on either side of Mission Road. That’s because that area was built when the steel pipes were most popular with developers, Johnson said. Areas to the north and south have considerably fewer feet of pipe that would need work. Leawood outlawed the metal pipes in 1996.
The majority of the existing metal pipes are in fair to poor condition, he said. Engineers will study whether to tear out and replace the pipes with concrete or reline them with a material that can be inserted and expanded inside the original pipe. That method has the advantage of not disturbing mature trees and landscaping, but it does somewhat decrease the size of the pipe, limiting capacity, he said.
The concrete pipes and liners have a much longer life expectancy, and water flows more efficiently through them than it does through corrugated steel, Johnson said. Concrete pipes can last about 100 years; liners last about 50 years.
The city will do its best to combine sewer replacement with street work, but staffers also have to decide which pipes are the most critical to replace, Johnson said. Staff has not yet set a timetable for which areas will go first.
The committee’s work Monday represents “proactive planning,” said Mayor Peggy Dunn. The city recently finished a project to videotape the pipes and culverts to get an idea of their condition.
“That took years to get done,” said Councilman Lou Rasmussen. “At least now we know where the problem is.”