By Tracy Overstreet
tracy.overstreet@theindependent.com

As part of the massive reconstruction project, the state is replacing an existing 6-inch water main under the north side of the highway with a 10-inch main under the south side.

"First of all, they increase their (water) capacity and also if you put in everything new now before you put the new street in, you shouldn't have to break up the street to get at it to repair it for several years," said Curtis Probasco, the Nebraska Department of Roads construction technician and inspector overseeing the water line.

But installing water main is no small task.

It has to go in a block or two blocks at a time so that the line can be flushed, pressurized and tested before it's added into the city's existing water distribution system.

It's a process that takes up long stretches of the street hence the full 15-block detour.

It also takes lots of time and involves lots of numbers.

The new 10-inch water main must be at least five feet below ground to prevent freezing, but it must not be more than nine feet deep so it can be accessed for repair.

It has to be separated from new storm sewer lines being installed to properly drain rain and snow melt from the new highway. The water main has to have 18 inches of vertical separation from new storm sewer lines and at least 10 feet of parallel separation.

Concrete thrust blocks that hold the new water main in place prior to pressurization have to set up for 48 hours.

Then starts a process of flushing water through the line, sanitizing the line with chlorine, pressurizing the line and conducting two rounds of bacteria testing, which must be done 24 hours apart and must have a finding of 0 percent bacteria.

"There's a week's worth of testing" on every block of water line, Probasco said.

Larger-sized commercial service lines then have to undergo specialized backflow testing before they can be hooked up.

"There's just a thousand things," Probasco said.

So far, so good, though.

Construction started on the water main from Clark Street one block west to Greenwich. That's from BG & S Transmissions to Lords and Ladies Hair Salon.

The first battery of bacteria tests were run at 1 p.m. Wednesday. Results were negative no bacteria so the second battery of tests were run at 1 p.m. Thursday.

If the second test is also negative, work could begin Friday to hook property owners on that block up to new service lines, Probasco said.

It will mean a temporary shutdown of individual water lines for about 30 to 45 minutes.

Probasco is coordinating with businesses to give at least a day's notice if a water shutoff may occur. That's key for the many businesses that rely on water to operate businesses such as restaurants, beauty shops and car washes.

"It's a scheduling challenge," Probasco said.

What the public can do to help keep the project moving along is to leave construction markings alone.

Probasco said some of the construction pins with pink flags have been removed from properties. That forces construction workers to take time away from installation work to remark the right of way.

Because of the tight nature of the construction zone, Probasco said, workers are already spending lots of time surveying.

"They see us out with stakes and levels all the time," Probasco said. "They will see us out surveying again and again."

The tightness of the project to fit within existing buildings also places workers very close to traffic.

Project Manager Scott Griepenstroh said concrete barriers were being installed at the Broadwell intersection to protect workers. Those barriers are also being shored to prevent the trenches underneath from caving in on workers.

The water main work at Broadwell is starting this week and will move east.

The trenches there are extra deep because storm sewer lines are being placed below the water lines.

Probasco said there are two to three places where the 18-inch vertical separation isn't possible between the ductile iron water main and the new concrete storm sewer, so a special process is being used. A narrower plastic pipe is being used for the storm sewer in order to clear over the water line.

"The slowdown to this whole project is the water line and the storm sewer," Probasco said.

"If we just had to put a street back, this thing would not take so long."

Construction is expected to continue into November.