Concrete trucks rev up for third intake project at Lake Mead

The road around Lake Mead will see a sporadic parade of concrete trucks Thursday, as material is hauled in to feed construction of a new water intake pipe hundreds of feet underground.

Starting at about 2 a.m., several dozen mixing trucks from a batch plant near Boulder City will deliver their loads to the third intake site near Lake Mead's Saddle Island.

The concrete will be dumped into buckets and lowered 450 feet underground to build a 20-foot-tall, horseshoe-shaped frame for a massive bulkhead where the third intake pipe links into a connector tunnel leading to the Southern Nevada Water Authority's two existing straws into Lake Mead.

It's expected to take 55 to 60 concrete trucks over a 24-hour period - or less than three trucks an hour - to complete the job, water authority spokesman Bronson Mack said.

At more than $800 million, the third intake is the most complicated and expensive construction job in the history of the authority.

It involves digging a tunnel 20 feet tall and three miles long under the lake bed to tap water from the deepest part of the reservoir.

The agency's board approved a rate increase earlier this year to help cover the last $360 million of the project.

Work at the site shut down for more than two weeks after Thomas Albert Turner, 44, was killed in a June 11 construction accident inside the main tunnel about 600 feet beneath the surface.

Since construction resumed June 27, the giant digger known as a tunnel boring machine has finished the first quarter mile of tunnel.

The entire project is on track to be finished in summer 2014, roughly 18 months later than its original completion date.

Thursday's concrete pour is tiny compared with one earlier this year to put in place a giant water intake structure on the lake bottom. That job took more than a week and required 12,000 cubic yards of concrete, or enough to fill roughly 1,200 mixing trucks.

But Mack said even a comparatively small task like this one is still plenty large and complicated, especially at a hot, soggy work site so far underground. After all, the 550 cubic yards of concrete set to be poured Thursday is about what you would need to build the foundations of about 20 average single-family homes.

"And being down 450 feet is nothing to joke about," Mack said.

Work on the third intake began in June 2008. The project is designed to keep water flowing to Las Vegas even if Lake Mead shrinks enough to force the two existing straws to shut down.

The Las Vegas Valley depends on the Colorado River's largest reservoir for about 90 percent of its drinking water supply. Henderson and Boulder City draw all of their water from the lake.

Contact reporter Henry Brean at hbrean@reviewjournal.com or 702-383-0350.