‘Historic’ breakthrough at Lake Mead comes during water board meeting

The “Eagle has landed” moment came at the start of Wednesday’s Southern Nevada Water Authority board meeting, when engineering director Marc Jensen stood to announce what many people in the room were already buzzing about.

“I have very good news to share with you,” Jensen told the board. “Today we are at a major milestone in our tunneling efforts.”

As he spoke, a 23-foot-tall, rock-chewing worm of a machine beneath the bed of Lake Mead was slowly and carefully grinding through the last few feet of a three-mile journey that began in 2011.

Three hours later, at one minute before noon, workers from general contractor Vegas Tunnel Constructors would guide the $25 million tunneling machine as it broke through the concrete wall of the intake structure already in place on the bottom of the lake, the last major step in building a third straw to supply water to the Las Vegas Valley.

“The evidence suggests the machine is precisely on target,” Jensen told the board.

The meeting room erupted in cheers and applause.

Jensen then displayed a photo taken earlier Wednesday morning showing a piece of fiberglass used to reinforce the concrete wall where the tunneling machine was just about to break through. When workers saw the fiberglass in the stream of material being funneled back from the machine’s cutter head, it further confirmed they were on target.

Las Vegas City Councilman and authority board member Bob Coffin said the piece of fiberglass reminded him of a cigar like the ones they would smoke at the NASA control center after a successful mission.

“I assume some of the guys out there (at Lake Mead) lit up a cigar and said, ‘My God, we’ve done it,’” Coffin said. “Anybody got a cigar?”

There were no confirmed cigar sightings at the job site, but workers underground and on a barge anchored above the intake did celebrate the moment with cheers and high-fives before getting back to work, said water authority spokesman Bronson Mack.

The third intake is designed to pull from the deepest part of the reservoir and keep water flowing to Las Vegas even if the lake shrinks low enough to shut down the two existing straws that supply the valley with 90 percent of its water.

Work on the now $817 million project began in 2008. In 2010, the job site 600 feet underground was twice flooded by slurry and rock, delaying the project and increasing its cost before the contractor could even get its massive tunneling machine lowered into the ground.

Water authority general manager John Entsminger said those floods raised serious doubts about the future of the “daunting” endeavor.

“It made you fear for the safety of the workers and for whether the project could be built in a reasonable time frame,” he said.

That’s what made Wednesday’s achievement all the sweeter. Entsminger said he “couldn’t be prouder” of everyone working on the project, which he called “the first of its kind in the world.”

“I think this is a historic day in Southern Nevada,” he said.

With the all-important connection now made between the intake structure and the three-mile tunnel under the lake, the project appears likely to meet its scheduled completion date this summer.

Starting Thursday, workers will lower a temporary bulkhead down from the surface of the lake to cap the intake structure, which is currently open to the water. Then they can drain the intake and begin disassembling the tunneling machine so it can be hauled in pieces back down the tunnel and up the 600-foot vertical access shaft, a process expected to take two to three months.

Once the tunnel is empty and ready to be put into service, it will be flooded using a newly built connector tunnel that links it to the two existing intakes. Then comes the final step: Removing the temporary bulkhead from the mouth of the intake to let in the lake, once and for all.

Contact Henry Brean at hbrean@reviewjournal.com or 702-383-0350. Follow @RefriedBrean on Twitter.