Summer of sinkholes: Cottage Grove stormwater employees hustle to keep up with growing repair needs
This summer was one of the worst for what public works employees can only call sinkholes.
The handful of major storms — rains of two inches or more, coming down quickly — did a number on the stormwater infrastructure by eroding holes in the area.
Stormwater foreman Gary Orloff said each year they inspect a fifth of the city's catch basins, outfalls, stormwater pipes and other related infrastructure — which ends up at about 1,000 items checked each year.
Orloff estimates they patch about 300 of those annually. There were 24 major repairs needed in 2013, but on average he said it's closer to 10 or 15 each year.
With new development, he anticipates about 20 to 30 new catch basins, stormwater ponds and outfalls are added each year.
The heavier rainfalls can cause water to rush in through any hole, crack or breakage in the infrastructure starts to swirl around, creating a kind of a vortex, "like a vacuum cleaner," Orloff said.
"That's when we usually find the little problems, is when you get those big, heavy rains because there's so much coming through and it creates that. Then it will show it's ugly face in the street," he laughed. "Or the yard."
Likely the largest sinkhole the city has worked on yet showed its face after one of this summer's storms. A sinkhole on Hadley Avenue started about 15 feet underground, beneath a pipe, when swirling water eroded under the pipe about six feet down.
Orloff said it took a full day and five workers just to patch the hole and the surrounding infrastructure.
Routine maintenance takes about a half hour on each unit.
"It's like maintenance on anything; if you don't keep it up, it's going to fall apart," Orloff said. "... It gets pretty involved if you don't have the routine maintenance."
Streets and stormwater employees have a trained eye to look for dips, depressions, holes or cracks that suggest sinking or eroding below ground.
A worker sweeping the leaves on Isle Avenue found a depression last week, and stormwater and streets employees Jeremy Goebel and Jeff Hendrickson got to work on repairs early Monday morning.
Though they do call them sinkholes, stormwater employees say they're not like the ones seen in the movies.
"We don't get them to that point," Orloff said. "That's not saying it can't happen, because it could be any reason, not just (bad) structures ... there could be a weird piece of ground. That's how that usually would happen."
"We haven't had one that's harmed the public," he added. "We've always been lucky enough to catch them."
The city council approved a new stormwater employee in the preliminary budget, so a new employee likely will be added to the team next year, though it won't necessarily help efficiency.
Due to OSHA (Occupational Safety and Health Administration) standards, there must be two employees on a work site, and when one is down in a sinkhole or catch basin, there must be another person keeping an eye on them. If the employee on the surface needs to lose sight of the person below ground for any reason, the one underground has to come out until the other employee is available again.
The new employee won't ensure a third person on the site to avoid this, since there is currently one designated stormwater employee and one often taken off streets department duties to assist with maintenance and repairs.
Orloff said he thinks the new staffer should help keep up with the sinkholes.
"I think for now (we'll be OK), but as the town grows... we're adding miles and miles of street, and eventually that's going to have to grow with it," he said. "I think it will help us in the meantime to be where we need to be."