Century Freeway: Caltrans’ ‘Dirty Little Secret’

For years, Caltrans has been pouring millions of taxpayer dollars into a stealth rescue operation to keep part of the Century Freeway--the most expensive highway in U.S. history--from collapsing due to erosion by underground water.

The problem results from decisions made decades ago to build a segment of the freeway below ground level. Caltrans ignored warnings about a shallow aquifer, internal reports show, and a 3 1/2-mile stretch of the freeway in Downey has been undermined as the water table rises and falls.

In an operation kept hidden from the Legislature and the public, the agency has spent $21.9 million since 1995 on underground repairs in a desperate effort to prevent pavement cracking and collapses on the segment of Interstate 105 between Interstates 710 and 605, documents and interviews show. The outer westbound lane and shoulder have been closed repeatedly since the freeway opened more than five years ago.

Last July, Caltrans quietly started constructing a new $41.4-million system of drains and pumps designed to stop the rising water table from undermining the roadway and endangering motorists.

Even when the new drainage system is finished next year, Caltrans will face another challenge: finding an inexpensive way to dispose of massive amounts of polluted water pumped from beneath the freeway. It is a problem, officials acknowledge, that may ultimately require them to build a water treatment plant, costing millions more.

“Unfortunately, the taxpayers are faced with having to pay millions of dollars in repairs for something that should have never occurred,” said Caltrans Director Jose Medina, who was appointed this year by Gov. Gray Davis. “It is our job to fix the problem, and we will do that.”

His predecessor as Caltrans director, James van Loben Sels, acknowledged in an interview that the Legislature should have been told about the severity of the problem. But, he emphasized, “there was no intention to hide anything.”

“Any new structure has some latent defects,” he said. “It was a serious problem, but as an engineer I thought we had a solution . . . and we proceeded on that basis.”

Mistakes were made in every gubernatorial administration involved in the design and building of the $2.2-billion Century Freeway, beginning with former Gov. Edmund G. “Pat” Brown in the 1960s, internal Caltrans reports say. Signs of potential ground-water problems were ignored. Steps that should have been taken to ensure the highway’s stability were skipped. Old design plans were used that should have been updated.

The freeway had been open less than two years when the first section of pavement buckled at the Bellflower Boulevard westbound onramp. Since then, Caltrans documents have logged “similar depressions and sinkholes” elsewhere on the westbound side.

“We knew there was a problem on the freeway when virtually after it opened lanes were being closed off,” said Downey City Manager Gerald Caton. “The explanation never really came out.”

Instead of alerting the Legislature and the public that the state’s newest freeway had a major defect, the agency attempted to cope internally with the underground water issue, drawing on maintenance funds to pay for the repairs. Work was completed gradually, and the magnitude of the problem was never disclosed.

“This was a dirty little secret that was unacceptable,” said Assembly Speaker Antonio Villaraigosa (D-Los Angeles). “I have had regular meetings over the years with [top Caltrans officials] and I have never been briefed on this issue. . . . And that’s unacceptable.”

Villaraigosa, who learned of the problem’s severity from The Times, said he plans to ask for an audit.

A Defect in a State-of-Art Freeway

Senate Transportation Committee Chairman Betty Karnette (D-Long Beach), whose district includes the Century Freeway, said she found out about the underground water issue only a few months ago. She was told by city officials in Downey, who were also in the dark until Caltrans advised them that the freeway had a water disposal problem.

Even then, Karnette said, she had no inkling that the problem was so severe that more than $60 million from gasoline taxes would be spent to fix it.

“I’m really, really upset,” she said. “When you get into this much money and this is in my district, I should have been told.”

Caltrans had told the press two years ago that the Century Freeway had a $9-million drainage problem that was causing the ground to sink in some spots. There was no danger to motorists because the agency had begun to contain the problem, Caltrans officials said at the time.

But internal documents showed that the problem was much more extensive. By the time Van Loben Sels left office Dec. 31, the cost of repairs had ballooned to more than $60 million. Still, nobody outside Caltrans was told.

To Caltrans officials, the discovery of such a fundamental flaw in the agency’s state-of-the-art freeway was upsetting. “It was not something we would expect to have taken place on a freeway of this age,” said Tony Harris, Caltrans chief deputy director.

When the Century opened in October 1993, it was celebrated as the capstone in California’s vast freeway system. The ribbon of concrete stretching for 17.3 miles from El Segundo to Norwalk was a source of pride representing the latest in transportation engineering.

It connected with four major north/south freeways--the San Diego (I-405), the Harbor (I-110), the Long Beach (I--710) and the San Gabriel River (I-605)--and provided six lanes of traffic and additional carpool lanes in each direction. The Green Line light rail system ran down the median.

But the costs and disruption of constructing what many experts believe may be America’s last major urban freeway had eclipsed anything on record. Construction was delayed for a decade by a lawsuit that led to a federal court consent decree in which Caltrans agreed to build affordable housing for those the freeway displaced, among other conditions.

With the social and legal issues so consuming, Caltrans officials were surprised to find they had a serious engineering problem. Initially, officials said they thought the pavement problem might only be at the Bellflower onramp, but as the pavement began to sink in other areas they concluded that the undermining was far more widespread.

In 1996 Caltrans assembled a team of in-house experts to investigate why the freeway “has been experiencing rapidly deteriorating conditions.” The team’s report, never made public, concluded that the highway was built with an inherent flaw that was left unattended in the haste to complete construction.

The critical design decision was made in the 1960s, the report said, when intense opposition from citizens in Downey and South Gate threatened to stop the freeway. Caltrans agreed to drop the roadbed 20 to 30 feet along a 3 1/2-mile stretch, making it virtually invisible to the surrounding neighborhoods.

But in lowering the roadbed, engineers nestled it snugly against a shallow water table that rises and falls with the vagaries of nature and the decisions of local water agencies to replenish the area’s aquifers by injecting water purchased elsewhere.

When the water table rose, it submerged a system of pipes and pumps built beneath the freeway to carry away storm water from the road. The soil around the pipes eroded, causing the ground above to give way and creating a cavity just below the pavement. The undermined road then cracked and, in sections, collapsed.

“What raised our concern,” said Harris, “is first we started to see the voids. . . . Then you can start to see pavement crack and collapse.”

Meanwhile, the sediment carried by the rising ground water filtered into cracks and joints in the storm-water system, clogging and destroying the drains.

Ground-Water Levels Went Unmonitored

Over the years, warnings of potential trouble were either discounted or ignored in the rush to complete the freeway. As far back as September 1968, a Caltrans memo suggested “that construction of a depressed section . . . is not feasible.” A month later another memo reversed that finding, noting that “no insurmountable ground-water problems are foreseen.”

Engineers in 1973 designed the drain system to catch storm water that collected on the freeway, but did not account for the possibility of rising ground water. In the 20 years before the freeway was completed, no additional testing was done to monitor water levels in the aquifer.

When this freeway segment was designed, Southern California was in a drought and studies located the water table 30 feet below the pavement level. By 1990, when the pavement was laid, water levels had risen sharply, fed by periods of heavy rain and decisions by local water officials to replenish the aquifers. Between 1986 and 1997 the ground water table rose 22 feet.

“No documentation was found to indicate there were any actions proposed to counteract the changing ground-water conditions,” the Caltrans report said.

During freeway construction, water surfaced in an excavation site for pumps, stopping work for more than a month, the report said. But that warning sign went unheeded because engineers assumed it simply showed that the new storm drains were working.

Less than three months after the freeway opened, the Northridge earthquake accelerated the subsidence problem by damaging the storm-drain system.

The earthquake displaced pipes and opened joints, allowing the soil eroded by the rising water table to flow into the drainage system. The sediment clogged up the drains, causing storm runoff to back up and further undermine the freeway, according to September 1994 internal memos. The same memos observed that Caltrans had signed off on construction of the drainage system even though inspectors had found problems.

Problem Keeps Bubbling to Surface

Throughout 1994 and early 1995, minor water-related problems continued to pop up along the freeway shoulders, but it wasn’t until the pavement failed on the Bellflower entrance ramp that Caltrans began to investigate fully.

“This is a disaster,” said former Assembly Transportation Committee Chairman Richard Katz (D-Sylmar). “What it looks like they tried to do, they tried to keep . . . anybody from ever finding out about it, and the only reason it’s coming out at this point is because it literally and figuratively keeps bubbling to the surface.”

As its latest solution, Caltrans has put in a series of deep wells on the north side of the freeway segment to control water elevation in the shallow aquifer. At the same time, it is constructing a new, stronger pipe system to collect storm runoff. Both measures, officials say, will ensure that the highway remains safe and causes minimal disruption to traffic.

But the need to pump out thousands of gallons of underground water to keep the freeway stable has thrown Caltrans into conflict with the local Water Replenishment District. The agency must pay $151 per acre-foot to, in effect, purchase the water, which it then simply dumps into the Los Angeles River, where it flows to the ocean.

“They [Caltrans] have no . . . rights to pump in this area,” said Tom Holliman, water district assistant general manager.

Caltrans will pump an estimated 10,000 to 15,000 acre-feet a year from the area, bringing annual costs to well over $1 million. An acre-foot is enough water for two typical Southern California families for a year.

Harris said Caltrans hopes to defray some of the water disposal costs by forming a partnership with some local entity that could make use of the water.

The water, however, is considered polluted, and Caltrans or whoever wants to use the water might need to build a costly treatment plant.

Downey city officials said they have approached Caltrans about jointly operating a treatment plant so the city can utilize the water.

“One of the things that has troubled us is having the water, in effect, being pumped to the river,” said Caton, Downey’s city manager. “But to make the water usable it has to be treated.”

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Troubled Stretch

A section of the Century Freeway--the westbound lanes stretching between the 710 and the 605 freeways--was built so low that the underground water table has undermined the roadway.

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Failing Freeway

Caltrans is spending more that $60 million to repair damage to the Century Freeway from an underground water table that the designers ignored. Rising and falling water levels undermine the earth supporting the roadway. The erosion problem is worst and storm drains that run beneath the freeway and shoulder.

1. 1960s decision: Community pressure forced Caltrans to drop roadbed 20-30 feet to keep it out of sight of neighborhoods.

2. Roadway undermined: When the water tables rises, it causes soil to erode, thereby undermining the roadway. Cracks occur and pavement can shift or collapse.

3. Drain system: A network of inlets and pipes were designed to move surface water but has been compromised by the rising aquifer.

4. Wells: Wells have been installed to lower the water level in the aquifer. The water that that is removed goes into the L.A. River and eventually to the ocean.

Century Freeway History

1958: First plans for freeway are drawn.

1968: Local opposition prompts a decision to lower part of the freeway.

1968: Internal Caltrans memo identifies the presence of ground water warns it is not “feasible” to lower the roadway. A month later, another memo reverses that advice, saying lowering the freeway would be “expensive but not impossible.”

1972: Lawsuit by environmentalists and residents is filed; construction stops.

1973: Storm water drainage system is designed using hydrological studies that locate the water table 30 feet below the pavement.

1981: Construction resumes. No additional testing is done to determine whether water table has risen.

1990: Storm water drainage system is constructed using the 1973 design.

1993: Freeway opens.

1995: Pavement collapses at Bellflower Boulevard on ramp as drainage pipes are submerged by a rising water table and soil around pipes erodes, creating holes in the ground above.

1996: Caltrans Director James van Loben Selis is briefed on the magnitude of the drainage problem.

1998: After spending $21.9 million on emergency repairs, Caltrans starts construction on a new drainage system and a series of deep wells designed to lower the aquifer. The price tag is $41.4 million.

2000: New drainage system expected to be completed.

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Source: California Department of Transportation