Water Users Heeding Call to Conserve

Rushing to repair a water-line break before more than 700,000 people run out of water, Orange County officials said Wednesday they were gratified by the swift response to a plea for conservation.

Meanwhile, water officials continue to seek a cause of the rupture and said they may consider a costly retrofitting operation to reinforce 170 miles of “prestressed” concrete pipe around Southern California prone to similar breaks.

Water use has dropped by 44% in some water districts since Monday, officials said, a clear indication that customers are scaling back their daily water-use habits. While much of the decrease was attributed to mandatory water restrictions placed on large-scale irrigation, residents have also done their part voluntarily, officials said.

“We’re relying on the residential consumers to get us through this,” said Karl Seckel, principal engineer of the Metropolitan Water District. “We need to continue to employ conservation throughout the duration of the outage.”

Seckel said repair crews are struggling around the clock to replace three 20-foot lengths of concrete pipe buried 25 feet below an Irvine strawberry field. The pipe, nearly 6 feet in diameter, ruptured like a bomb going off Monday morning, sending shards of concrete spearing up to the surface and into the air. More than 5 million gallons of water were spilled before the flow was cut off, restricting supplies to homes and businesses.

Investigators suspect the 20-year-old pipe is prone to corrosion because it is made of the prestressed concrete material that has been blamed for several other costly pipeline ruptures around the country.

Officials said Wednesday that they also suspect a sharp surge in water flow--from 3.2 million gallons per hour to 4.5 million--was a contributing factor. The surge could have been caused by a valve malfunction somewhere along the 26-mile pipe, which stretches from Yorba Linda to Mission Viejo.

Reservoir May Run Dry if Repairs Are Delayed

If repair work on the ruptured pipe is completed by Sunday as expected, normal water service would be restored the next day and a potential water shortage crisis would be avoided. The break affects water supplies in Irvine, Lake Forest, Laguna Woods, Trabuco Canyon, Santiago Canyon, Mission Viejo, Rancho Santa Margarita, San Clemente, Laguna Hills, Dana Point, Laguna Niguel, Laguna Beach, Aliso Viejo and Foothill Ranch.

Three water districts--Los Alisos, Santa Margarita and Moulton Niguel--are receiving assistance from other agencies and cities through a vast network of smaller water lines linked to neighboring communities. But even with continued conservation cooperation, at least one South County reservoir could run dry within a week if the repairs are delayed.

“It’s a race against the clock. . . . They’re moving as fast as they can,” said Stan Sprague, general manager of the Municipal Water District of Orange County. “Those who haven’t stepped up could do us a world of damage,” he said.

South County residents have been asked since Monday to conserve water by taking shorter showers and minimizing laundry loads. Officials are also asking residents not to water lawns or wash their cars, a request that most South County neighborhoods have readily complied with.

Dave Seymour, operations manager of the Mission Viejo Water District, said the district shut off some of the larger water users, such as construction crews, school districts and the city’s Park and Recreation Department. In Mission Viejo, 1,800 larger water users and 75 construction sites were affected.

In the Los Alisos Water District, 400 large water users have been shut off, said Ken Petersen, the district’s general manager, adding that the district has storage for seven more days.

In Mission Viejo, district workers will patrol neighborhoods for excessive water use and remind residents to conserve, Seymour said. Conservation remains voluntary for homes and most businesses, officials said.

Mark Bernard, a property manager at the Knolls condominiums in Lake Forest, said he unhooked the hoses at six car-washing stations throughout the 160-unit complex to comply with conservation efforts Wednesday. A notice had already been taped to residents’ garage doors urging them to use discretion with laundry, showers and dishwashing. Neighbors so far have been cooperative and tolerant, he said.

“We’re just trying to do our part here,” said Bernard, who manages another complex in Mission Viejo, where similar conservation steps are being taken. “We decided to remove the [carwash] hoses so people would take this thing seriously. There may be an end in sight, but anything could still happen.”

Neighbors along Barlovento in Mission Viejo--where water from garden hoses and sprinklers usually flows freely down the sloping street--have changed their ways.

“I guess I’ll drink wine instead,” said Neil Lansinger, a retiree. “People who have lived in California are used to droughts.”

Lansinger said he would follow common-sense advice, such as consolidating laundry loads and not washing his two vintage Fords. “It’s a fair request,” he said.

Design of Pipe Called an Engineering Error

Meanwhile, experts said this kind of rupture was a disaster waiting to happen; the concrete design of such pipes makes them prone to failure and has been the subject of lawsuits around the country after ruptures that began in the 1970s.

Prestressed concrete water mains have exploded across the nation, included in water systems in Ventura County; San Francisco; Washington, D.C.; Tampa, Fla.; Tucson; Milwaukee; and Richmond, Va.

“This design is one of the biggest engineering errors in the 20th century,” said Don Kendall, general manager of Calleguas Municipal Water District in Ventura County.

The basic frame of a prestressed concrete pipe is a thin steel tube with a 2-inch layer of concrete bonded to the inside and a 4 1/2-inch layer of concrete bonded to the outside. Steel wire is wrapped around the outside--giving the pipe its strength--and is covered with a layer of mortar to prevent rust.

Of MWD’s 475 miles of pipeline, stretching from Ventura County to the Mexican border, about 170 miles is prestressed concrete pipe. Because such pipes are prone to corrosion, the water officials drain and inspect the inside of all of them on a five-year cycle.

The agency no longer installs the concrete pipe, opting for welded steel pipe segments instead. And officials said the agency is studying the possibility of fitting steel pipe inserts into concrete lines to prevent future ruptures.

In Orange County, segments of the concrete pipe run underneath Buena Park, Yorba Linda and portions of Anaheim, said Eddie Rigdon, assistant water system manager for the MWD.

Although some portions of that pipeline run through residential areas, there is a 40- to 100-foot easement--or land buffer--between the buried water main and any residence or business, which would prevent injury or property damage from flying debris after a rupture, Rigdon said.

The water district’s corrosion experts are conducting a forensic analysis of the ruptured pipeline and, when the preliminary investigation wraps up Friday, they expect to announce the most likely cause of the break, said Jill Wicke, a manager at the MWD.

Only nine miles of the 26-mile water main that burst consists of concrete pipe. While the water main is being repaired, water officials are inspecting the other concrete segments with acoustic sound equipment to detect evidence of corrosion, Wicke said.

In Simi Valley in Ventura County, corrosion was blamed for a burst in a 5 1/2-foot-wide water main two years ago. The water district has taken legal action against the contractors and manufacturers, including Ameron Concrete and Steel Pipe Group in Rancho Cucamonga, the same firm that manufactured the segment that ruptured in Orange County.

Kendall said the water district is spending millions of dollars to retrofit the concrete pipe, slipping welded steel pipe inside the water mains.

Customers may call the MWD with conservation questions at (800) 225-5693.