Airport utility extension project crews work through water issues

A high water table has been creating issues for contractors working on the Brainerd Lakes Regional Airport utility extension project.

Before a contractor digs deep trenches or excavates, they need to dewater, City Engineer Jeff Hulsether said. Dewatering puts down wellpoints and lowers the elevation of the water table, he said. This prevents water from coming into the hole as the contractor is digging.

"I know it's been a challenge for them," Hulsether said, of project contractor Tom's Backhoe Service.

Part of the project involves building a lift station in the Lum Park area, which requires digging a deep hole. There's a high groundwater table in the area, Hulsether said, which can make it difficult to dewater.

"I think everyone understood going into the project that some of that was going to be a challenge," Hulsether said. "Regardless of the contractor, they would have had to deal with the dewatering issues."

Not dewatering enough before digging a trench can create instability in the trench, Hulsether said. Trenches need to be dry in order for pipes to be laid and "stay where they're supposed to," he said.

The project features a lot of directional drilling, which requires pits on both ends of the area being drilled, Hulsether said. It's important for those pits to also be dry and stable, he said.

There are different ways to dewater, Scott Hedlund said. Hedlund is the project manager with Short Elliott Hendrickson, the consulting engineer on the project. It's up to the contractor to decide how they want to dewater, he said.

"We don't dictate how they go about doing it," Hedlund said. "But they do need to lower the water in the area of the lift station in order to properly install it."

Tom Thompson, owner of Tom's Backhoe Service, said the airport project is just like a normal job. There's a lot of water coming out of the ground, he said, but what's also causing issues is the rain.

"It just makes the job a lot more challenging," Thompson said.

There's a lot of water trapped in the ground between layers of silt, clay and sand, Thompson said. Most of the issues have been in the Lum Park area, he said, and have gotten better the farther crews get from the park. Professional dewatering companies have been handling the dewatering part of the project.

"We've gotten through most all of it now," Thompson said.

Crews have been using a bentonite slurry to aid in directional drilling, Hedlund said. The slurry lubricates the hole so crews can pull the pipe back, he said. If the slurry gets into an area where crews are dewatering, it can cause problems by clogging up soil they're trying to dewater. He said it wasn't possible to pinpoint a specific issue that would be causing problems for crews trying to dewater.

"That's not the main cause of (the dewatering issues)," Hedlund said.

Noise complaint

Because of the issues, crews have been working longer hours to stay on schedule. The regular work hours for the project were set at 7 a.m. to 7 p.m. Monday through Friday. But crews have been working on Saturdays and past 7 p.m. during the week in order to finish the project on schedule, Hedlund said.

These longer hours caused a noise complaint on June 1, which resulted in the Brainerd Police Department being called.

According to the incident report from the Brainerd Police Department, a noise complaint was called in at 10 p.m. June 1 from the intersection of I Street and 13th Avenue Northeast, just west of Lum Park. An officer first arrived on the scene at 10:09 p.m. and cleared the scene 12 minutes later at 10:21 p.m.

Roger Worm, SEH field representative, spoke with the officer and said he was responsible for overseeing the contractors working on the water main. Within the contract, Worm said, they were only allowed to work until 7:30 p.m.

The officers then spoke with Jeff Hyatt, onsite supervisor for Tom's Backhoe Service.

"Hyatt and Worm disagreed on the allotted timeframe as to when they could work until, and Hyatt made comments about them only being able to work for six or seven months out of the year," the incident report reads. "It was explained to Hyatt that with it being 10 p.m., it was not unreasonable for neighbors in the area to be concerned about noise at that hour."

The workers shut down the equipment for the evening and officers left the scene shortly after.

The fact the police department had to be called to shut down work for the evening is rare, Hulsether said.

Crews were tying into a water main and had issues with the fittings, Hulsether said. They wanted to complete it instead of leaving it to be completed the next day, he said.

Hedlund said crews were performing water main work at an intersection and had generated noise complaints from residents in the area.

"It's not unusual for police to come if there's noise complaints or people to call on that for construction sites," Hedlund said.

The incident caused project management staff to review the work hours, Hulsether said. There may be emergency situations when a crew may have to work later to finish a task, he said, but should stick to the daily 12-hour work window.

It's a balancing act when it comes to getting construction projects done in Minnesota's short construction season, Hedlund said. Workers are trying to take advantage of the longer daylight hours to get as much done as they can, he said.

By the time police officers arrived on the scene on June 1, crews had already stopped working, Thompson said. They arrived because of a safety issue, he said, because they "didn't want the water main blowing apart."

"That's what they were doing, was making sure that didn't happen," Thompson said.

Crews don't plan on working until 10 p.m., Thompson said, because they aren't very productive when it's dark out.

"But sometimes when you have to work, you have to work," Thompson said.

SPENSER BICKETT may be reached at 218-855-5859 or spenser.bickett@brainerddispatch.com . Follow on Twitter at www.twitter.com/spenserbickett .