Workers Patching Leaky Pipes Under Lake Las Vegas

Sun January 04, 2009 - West Edition
Henry Brean -Las Vegas Review-Journal




HENDERSON, Nev. (AP) Deep below the tranquil waters and fancy trappings of Lake Las Vegas, work has begun on a repair job designed to ensure the future of one of Nevada’s most opulent neighborhoods.

The $3 million project is expected to extend the life of two pipes that allowed the development to be built. The 7-ft.-wide (2.1 m) pipes divert the flood-prone Las Vegas Wash beneath the artificial lake, but they have deteriorated sooner than expected since their completion in 1990.

So how do you fix something that’s buried under about 80 ft. (24.3 m) of earth and water?

Slowly.

Each pipe is 2 mi. (3.2 km) long, with only one way in and out for the eight-person crew that will make the repairs.

Workers, material and equipment must be hauled into the tunnel in special vehicles that then have to back their way out.

And it’s dark in there, said Mike Michelson, project superintendent for Hydro-Arch, the construction firm based in Henderson that was hired to do the work.

“It’s a black you’ve never seen before,” he said.

Lake Las Vegas Resort and Hydro-Arch planned the job for three months. Work on the pipes began in earnest a few weeks ago, and the repairs are expected to take six months.

“It’s not something that gets done overnight,” said Kirk Brynjulson, vice president of land development at Lake Las Vegas. “Getting it done quickly is not the goal. It’s getting it done correctly.”

When the development filed for Chapter 11 bankruptcy in late July, corporate officials said the pipes needed urgent repairs to prevent a failure that could drain the lake like water from a bathtub. Some observers dismissed that warning as hyperbole meant to bolster the development’s request for $127 million in post-bankruptcy financing.

During a recent interview, Jim Coyne, the resort’s senior vice president and chief operating officer, wouldn’t predict how long the worst of the two pipes might last without repairs.

Brynjulson wouldn’t speculate either, but he stressed that failure was not imminent.

“If it was falling apart, we wouldn’t have people inside of it,” he said.

The pipes are wearing at the bottom, especially where they bend to follow the wash’s original path. In places, rocks and other debris have scoured holes that eventually could cause the pipes to fail.

To fix the problem, a layer of high-strength concrete will be applied to the entire length of both pipes.

Michelson and company are starting in the south tunnel, which was shut down several years ago because of deterioration. Once that tunnel is done, the wash will be diverted into it so the north tunnel can be drained and fixed.

Workers are stringing utilities through the south tunnel, including a communication cable, a water line, a compressed-air line and hundreds of LED lights.

The job calls for a quick-setting concrete mix about five times harder than the stuff used for house foundations. Workers will start applying it at the end of the pipeline nearest Lake Mead, and work their way west at a snail’s pace.

Early on, they expect to pour as little as 3 yds. (2.7 m) of concrete a day. In the same amount of time, a crew at a tract-housing development might lay more than 300 yds. (274 m) of concrete, enough for slabs of eight homes.

The workers start each day with a 5:45 a.m. safety briefing and are usually inside the pipe by 6 a.m. They often don’t see daylight until the end of their eight-hour shifts.

When lunch time rolls around, they “eat in the hole,” Michelson said.

Hydro-Arch specializes in culverts and other flood-control structures, but this was something new for the company. It had to design a few pieces of equipment and modify several others to accomplish the job.

Special plastic-lined carts filled with concrete will be linked like train cars and hauled, up to six at a time, through the pipe by a pair of small Bobcat tractors equipped with filters to reduce their diesel exhaust.

A large electric fan is used to draw air through the pipe and carry away any noxious fumes, which creates an endless, 8 mph breeze that blows cold near the pipe’s inlet.

The temperature inside the pipe hovers somewhere in the upper 60s or lower 70s.

“If you work construction in Las Vegas, especially during the summer, it’s kind of pleasant,” Michelson said.

Of course, “pleasant” is a subjective term when you’re standing inside a concrete and steel tube at the bottom of a lake.

Hydro-Arch safety director Andrea Scott said she is mildly claustrophobic but feels pretty comfortable inside the pipe because it is tall enough not to feel too confining.

Brynjulson described his experience there as a “hell” of darkness and constant pressure.

“I’m not a miner for a reason,” he said.

Michelson said several of his employees also expressed discomfort about the pipes and were assigned to other projects. The workers who did sign onto the Lake Las Vegas job had to undergo confined-space training and learn CPR and basic first aid.

Each of them carries an air monitor and a rebreather tank about the size of a lunch box that can deliver up to an hour’s worth of emergency oxygen.

From her office in a nearby construction trailer, Scott stays in constant communication with the workers. A golf cart modified to carry a stretcher and first aid gear stands at the ready in case of an accident.

Scott also monitors the weather and the water level in the Las Vegas Wash using the Clark County Regional Flood Control District’s Web site. She said the county’s early warning system can provide several hours’ notice of a flood, more than enough time to move equipment to higher ground and evacuate the work site.

The wash carries a constant flow of treated wastewater from the Las Vegas area to Lake Mead. It also serves as the valley’s only outlet for storm water and urban runoff.

Lake Las Vegas was built right in the middle of that wash’s channel. The 3,592-acre development is home to three golf courses, two high-end hotels, a casino, an outdoor shopping mall and more than 3,300 residents.

In the event of a major flood in the wash, the twin diversion pipes are designed to carry some of the flow while the lake takes the rest. Some of the floodwater can then be released from the lake through a 4,300-ft.-long earthen dam.

The pipe repair project is scheduled for completion at the end of March, but Michelson said it could wrap up early barring a winter filled with storms and floods in the wash.