ASHLAND — The next source of Lincoln’s water supply is a bright-blue 1,500-foot steel straw, supported a few feet above the muddy Platte River bottomlands halfway to Omaha.
And there’s an engineer on a skateboard scooting around somewhere deep inside it, carrying a flashlight and digital gauge, making his final inspections.
Everything has to be perfect for Lincoln’s first delivery of water from Omaha’s side of the Platte.
The welds joining dozens of 50-foot sections of pipe need to be watertight, the anti-corrosive coating needs to protect them, this sloppy ground needs to be firmer to bear the weight of heavy equipment.
Most importantly, the weather needs to hold.
If all of that happens, the Lincoln Water System and its hired hands will embark late this week on a 24-hour continuous operation to pull the pipe — as long as five football fields and as tall as a 6-year-old — deep beneath the river and back up to dry land, where it will connect to the existing system that delivers water to your faucets, toilets, sprinklers and showerheads.
The far side of the river
A brief history lesson: Lincoln’s leaders started buying land around the Platte near Ashland decades ago to secure a more reliable water supply.
It sunk all the wells it could north and south of U.S. 6, on the Lincoln side of the river. Then, in the 1990s, it began tapping its 143-acre island north of Interstate 80 with a new kind of well.
These weren’t the traditional vertical wells found in a farmyard. Viewed from above, horizontal collector wells would resemble wagon wheels, with a central chamber 16 feet across and water-filled spokes radiating out up to 200 feet, collecting five to eight times more water.
To get all that water from the island to the Platte’s west side, the city temporarily dammed the channel and dug deep into the river bed, burying a pipeline.
“We actually open-cut the river, and it was something to see,” said Steve Owen, the city’s superintendent of water production. “But today’s environmental concerns and permitting really almost prevent that kind of activity. Hence, this new technology we’re using on this project.”
This project marks a first: Lincoln Water’s maiden voyage to the other side of the river. And it can be traced to the drought of 2012, which forced the city to order mandatory restrictions and made clear the need for more wells.
That dry summer tested the water system, Owen said.
“That was a time that we said, ‘OK, now is the time to get more serious about increasing our supply.’”
The city finished the final well the island could bear in 2014, but got a good price at the time from the driller to sink a well on the river’s east side, Owen said.
It sat unused for a couple of years, but now the city is ready for it to start pumping. First, though, officials had to figure out how to get that water flowing into the pipes already on the island.
Contractors have been preparing for this for months.
They built access roads so trucks could deliver the 30 sections of steel pipe that will slide below the river. Beneath a tangle of trees and with the interstate in the distance, they set up outdoor workstations to weld, sandblast and coat the pipeline, supporting its growing length on a series of steel cradles with rollers.
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Another crew bore a 7-inch pilot hole between the island and the east side of the river. The pipe will follow this path, a gentle U-shape that, at its deepest, dives 50 feet beneath the river bed.
With all of the wildlife and wetlands, it made the most sense to go below the Platte, Owen said.
“The reason we chose this method it to avoid environmental issues,” he said. “Other than where you insert the pipe and where it comes out of the ground, everything in between, there’s no impact.”
And they’re going deep not to protect the river from the pipeline — it will be carrying water, after all — but to protect the pipeline from the river. If the river scours and the bed sinks, the pipe will remain safe, he said.
It’s a complicated and expensive undertaking, with an estimated $12.7 million price tag to get the well working and supplying the water system, and to stabilize stretches of vulnerable riverbank. The state Water Sustainability Fund will pay 60 percent, or up to $7.6 million, Owen said.
Last Thursday, the east side of the river was quiet, with just a few workers moving mud and reinforcing the insertion site, and the engineer on the skateboard, examining the dark interior of the pipe.
This place will be busy next week, though, if the operation begins on schedule.
First, contractors will move a bigger reamer through the hole beneath the river, enlarging it to 60 inches. Then it will swab the hole, running another reamer through to smooth the walls and prepare it for the pipe, said Joel Jirak, an engineer with Olsson Associates.
That will take three days.
Finally, they’ll turn their attention to the pipe, Owen said. “And that will be the impressive part of this whole project.”
They’ll weld a torpedo-shaped nose to its front end, grasping it with a pair of cranes and guiding it toward the hole in the ground, where it will be attached to the drill stem and slowly pulled west.
The steel pipe is rigid, three-quarters of an inch thick, but such a long length will bend to follow the route below the river. “You don’t think of steel pipe as being something that has movement in it,” Owen said. “But put an eye on that pipe and you can see some up and down; that gives you a sense of the flexibility.”
The hole will be filled with a bentonite-based drilling fluid to stabilize its walls, and the pipe filled with water to reach negative buoyancy, so it doesn’t float during its trip.
On the island side, the fluid pushed out by the advancing pipe will be pumped into a temporary, 2.5-million gallon holding tank, which resembles an oversized above-ground swimming pool.
Later, the 1,500-foot pipe will connect to the new well on the east and existing supply lines to the west. The crew will clean the work sites, disassemble the pool, haul away all of their heavy equipment.
And up to 10 million gallons of water could be flowing beneath the river this summer.
But first, all of their planning and preparation have to get them through this day. And it will take at least a day — a nonstop 24 to 30 hours of choreography with little margin of error, Owen said.
“You don’t take any breaks once the pipe is moving.”