REGION: Proposed tunnel project passes milestone

With drilling finished, soil and rock samples will be analyzed

By AARON CLAVERIE - Staff Writer | Sunday, November 23, 2008 5:54 PM PST ∞

CORONA ---- Months of drilling in the Cleveland National Forest has produced soil and rock samples that will be used to determine if an audacious idea ---- a tunnel for commuter traffic linking Riverside and Orange counties ---- is an engineering possibility.

The idea of building an 11-mile tunnel, which would be one of the world's longest tunnels for cars, under the Santa Ana mountains is one of three traffic congestion relief measures that are being studied by the Riverside Orange Corridor Authority.

The public agency, made up of transportation officials from the two counties, was formed to improve mobility and reduce congestion for the hundreds of thousands of commuters who shuttle back and forth each workday on Highway 91.

The other two relief measures, a pair of comparatively more mundane options, are widening Highway 91 and constructing a four-lane elevated roadway parallel to Highway 91.

John Standiford, spokesman for the Riverside County Transportation Commission, said the drilling work, conducted by the San Diego-based engineering firm Kleinfelder, was wrapped up this month and all reports on the work have been positive so far.

"I don't know of any big red flag that has been raised," he said.

H. Tony Rahimian, the lead engineer on the project, agreed with Standiford's analysis.

"Based on the studies that we've done so far, we haven't seen any fatal flaws," he said. "But that doesn't mean we're done with our investigation."

Rahimian, president of RMC Inc. of Santa Ana, said that in the next six to seven months engineers will sift through all of the samples and produce a report that details the geological composition of the tunnel's possible route through the mountains. The draft version of that report should be ready by the middle of 2009, he said.

Standiford said the authority also will be using some of the federal money allocated for the project to monitor groundwater levels during different seasons throughout the year to make sure the proposed toll-road tunnel, which has been designed to handle 70,000 vehicles a day, won't face any flooding issues.

The information in the reports will help the authority get a better handle on the ultimate cost of the project, which was pegged at $6 billion two years ago, he said.

The final report, combining all of the studies, likely will be presented to the authority around this time next year, Rahimian said.

That report will be an important milestone in the project's life cycle, Rahimian said. If the report is positive, the authority board could greenlight the next phase of the project, which involves preparing environmental and preliminary engineering documents.

That phase of the project likely will take years to unfold as it involves securing approval from the U.S. Forest Service and a host of other federal and state agencies.

Extracting the soil and rock samples involved sinking a 1-inch drill attached to a 1.5-inch tube ---- the equivalent of a long straw with teeth ---- to depths of 1,000 to 1,500 feet, Rahimian said.

As one can imagine, the process was time-consuming and Kleinfelder engineers spent most of the summer in the Cleveland National Forest.

During the same week those engineers finished the drilling operation, Riverside's transportation commission held a public hearing on the proposed Mid-County Parkway, a proposed east-west freeway that would connect interstates 15 and 215.

The preferred route of the parkway would put the I-15 interchange near the existing Cajalco Road interchange. That area also has been proposed as the potential mouth of the tunnel on the Riverside side.

If both projects become a reality, it might one day be possible to drive from Irvine to Perris without using Highway 91, I-15 or I-215.

Standiford said the two projects are not linked ---- they each require separate project-specific environmental documents ---- but he also has noticed the possible route.

"Physically, that might happen one day," he said.

When the tunnel was first proposed, critics of the project questioned the wisdom of building it near an active earthquake fault.

Rahimian is well aware of those concerns. He said the proposed alignment of the tunnel does not cross any known active faults.

In addition to the fault question, some people are worried about traffic accidents inside the tunnel.

In 1999, 39 people died when a truck exploded inside the 7-mile Mont Blanc tunnel that links Italy and France.

Rahimian said those safety worries are valid and, at a public meeting on the project, scheduled for Dec. 19, he plans to make a series of recommendations on how best to study those types of issues.

If those studies are approved by the authority subcommittee, Rahimian said engineers will be spending some additional time next year studying ventilation and the safety of the tunnel in an earthquake.

Ideally, Rahimian said he would like to have documentation that covers any and all types of safety concerns commuters might have.

Gary Thompson, a Rancho Santa Margarita city councilman, has been involved with the tunnel project since it was first proposed a few years ago.

Early on in the project's gestation, the tunnel was proposed to funnel traffic into the middle of Thompson's city. It has since been moved so that the tunnel will empty near the interchange of highways 133 and 241, a much more palatable spot, Thompson said.

Recently, in his role as acting city manager of Menifee, Thompson has been commuting on Highway 91 to Menifee from Rancho Santa Margarita.

Although he is traveling against the flow of normal commuting traffic, it still takes him about an hour to get from his house to Menifee.

If the tunnel was a reality, the trip might take close to half that time.

Thompson said that the tunnel might be the only viable way to alleviate cross-county traffic if there's not a better way to fix Highway 91.

A plan to build a second level on Highway 91 ---- the double-decker freeway idea ---- has been taken off the table, leaving only a few other options.

Looking at the project from a safety and an environmental angle, Thompson said he's not concerned about the danger of a fire or an earthquake.

"Not for me. All those items can be engineered out," he said.

He's most concerned about the pollution belched out by cars idling on Highway 91.

If there's a way to get those cars off the road and into a tunnel ---- a route equipped with pollution scrubbers that would capture the exhaust from the vehicles ---- Thompson said it should be considered.

Allen Baldwin, a former Lake Elsinore councilman who will become the city treasurer after election results are certified, commutes across the Santa Anas on Highway 74.

During the decades he has spent as a commuter, he has heard plenty of talk about doing something to alleviate traffic on Highway 91.

While he doesn't dispute that there is a need now, he's not sure there will be a pressing need in the future.

Baldwin said that by the time the tunnel is a reality ---- 2023 has been mentioned as a possible grand opening date ---- there could more telecommuting and a healthier Southwest County and Riverside County job base, making the tunnel obsolete.

"We never anticipate the future quite properly," Baldwin noted.

Contact staff writer Aaron Claverie at (951) 676-4315, Ext. 2624, or aclaverie@californian.com.