Cutback Allows Aqueduct Overhaul

Completing the most exhaustive overhaul of the Colorado River Aqueduct in five decades, the Metropolitan Water District began today to refill the system that delivers a billion gallons of water each day to 18 million people across Southern California.

Two hundred and forty-two miles of aqueduct -- spanning desert and mountains from Lake Havasu to Lake Mathews near Riverside -- was shut down and drained Feb. 5 for inspection and repairs at a cost of $8.2 million, district officials said.

By Friday, the reservoirs, canals, pipelines and tunnels should be fully back on line.

The opportunity to upgrade the aqueduct was an unexpected benefit of the U.S. Department of Interior’s recent decision to reduce by nearly half the amount of water the district would receive this year from the Colorado River.

Many feared the reduction would affect the water supplies of some of the region’s fastest-growing communities. But the giant water district simply began drawing from reserves such as Hemet’s Diamond Valley Lake, which holds nearly 800,000 acre-feet of water -- more than enough to handle demand.

The closing enabled district workers to do some things they have never done before, such as inspect every inch of the aqueduct, including 92 miles of tunnels, 63 miles of open concrete channels, and every siphon, turnout and reservoir along the way.

They coated below-ground head gates at remote pumping plants and reservoirs with sealant, drained picturesque Copper Basin Reservoir near Lake Havasu for repair work and used helicopters to drape aqueduct walls with special netting to prevent erosion. Roughly 100,000 square feet of canal concrete was replaced.

They inspected the entire length of the 13-mile-long, 16-foot-high San Jacinto Tunnel -- an engineering monster designed with slide rule and survey equipment, and excavated with dynamite and hand shovels beneath the third-tallest mountain in the state.

Yet MWD’s millions of customers had no idea that the Southern California water lifeline -- designated a “modern wonder of the engineering world” by the American Society of Civil Engineers -- had been shut down.

Irving Sherman, past president of the engineering society’s Los Angeles section, called that “a tribute to the people on whose shoulders we all now stand.”

“They designed and built something so vital so well,” he said, “that you can shut it down without people noticing.”

Protecting the integrity of aqueduct components such as the San Jacinto Tunnel -- which took 5 1/2 years to build -- has been a life’s work for district employees such as David Phillips, a senior environmental specialist, and Eddie Rigdon, assistant manager of water system operations, who took advantage of the shutdown to conduct tours of its dark, dank interior.

The tours aimed to show off the enduring quality of the tunnel’s engineering and workmanship. But they also sent a message to the federal government and other water users: The MWD is well-prepared for reductions in its supply.

District officials have said there is enough water in their reservoirs and aquifers to offset the loss of surplus water for at least two more years. That could give the district more leverage in complex negotiations over how Colorado River water should be shared.

Toting an ice chest filled with emergency safety equipment on a recent weekday, Phillips led eight people clad in rain gear, hard hats and knee-high rubber boots to the tunnel’s starting point: a long flight of metal stairs descending into a black void filled with the sounds of rushing water.

“Here we go!” Phillips said, as the group tromped behind him, down the stairs and then along an ankle-deep stream of water to a “hay wagon” connected to a small green tractor.

With everyone on board, driver Greg Williams rumbled into the darkness at about 3 miles per hour.

“You’re going to get a rare glimpse of a place not seen but once every several decades,” Phillips shouted above the roar of the tractor engine and its echo. “Inside are many mysteries of construction.”

Every few hundred yards, Williams shouted “Water!” to warn the group that it was about to pass under torrents bursting from seams and holes in the tunnel walls, which are 2 feet thick. The water was so laden with minerals in some areas that it smelled like rotten eggs.

The first stop was at the remains of a pumping plant 800 feet beneath the surface, where a grim little company of hard-rock miners and engineers barely survived a flood in April 1936. The men scrambled up a safety ladder with gurgling water lapping at their boots all the way.

An hour into the tour, Williams braked for the so-called car wash, a euphemism for a column of groundwater blasting through a hole in the concrete floor and exploding on the ceiling. A few more miles down the line was “old horizontal,” an even stronger blast of groundwater shooting directly across the tunnel, as if from a fire hose.

Phillips gave assurances that breaks are not unusual and that the tunnel is structurally sound. The gushers were created six decades ago, he said, when spring water under tremendous pressure burst through weak spots in the drying concrete.

Then came the “Cabazon adit,” a deep grotto containing a pool of azure spring water teeming with crawfish, and the “pioneer tunnel,” a hole gouged out of the tunnel wall that was encrusted with small purple clams.

As the tractor rig rumbled along the final stretch of gray walls riven with leaks and studded with pale yellow stalactites, Rigdon smiled and said, “Everything looks favorable, despite the fact that this is a nearly 70-year-old system.”

Added Rigdon: “I believe we’ll get another 75 years of use out of it.”

Metropolitan officials are not planning to shut down the aqueduct and reenter the tunnel again until 2005. However, said an MWD spokesman, Bob Muir, “if we continue to fall short in surplus water supplies, we may go back in as early as next year.”