(The following story by David E. Graham appeared on the San Diego Union-Tribune website on July 11.)
DEL MAR, Calif. — With nature’s assault of rain, wind, waves and storms, the train track that hugs the coast along Del Mar’s bluffs would some day likely tumble into the sea.
Slowly, perhaps inexorably, the bluffs are eroding and sections could collapse.
But to retard erosion and save the track, the San Diego Association of Governments has begun an engineering project to place steel I-beam support pilings encased in concrete deep down into the bluffs over a 1,300-foot-long span of the coast where the track is closest to the ocean – in spots about only 20 feet from the edge.
“Left unchecked, with the waves crashing at the toes of the bluffs and with water leeching out above them, the bluffs could wash out and take our track with it,” said Tom Kelleher, spokesman for the North County Transit District, which owns the track.
For riders of Amtrak passenger trains, commuters on the Coaster and crews on freight trains, the bluff track offers quite a view of the Pacific.
Now the SANDAG project has become visible, too. In May, contractors started draping orange plastic fencing along sections of the track to catch debris and to protect native plants, said Ramon Ruelas, SANDAG’s project manager. Crews have a staging area near 15th Street in Del Mar.
Last month, they began spreading gravel on either side of the track to support the equipment that at night will drill into the earth and place the columns that will help support the bluff’s weight. During the last days of June, they began drilling the deep holes for the columns.
The work is being done from 10 p.m. to 5 a.m. Sundays through Thursdays to minimize disruption to train schedules. The work started between 11th and 15th streets in the north and will move south around Eighth Street and around Anderson Canyon.
“You’d like to do a preventive strike so you can stabilize these over the long term,” Kelleher said.
“The history of the bluffs has been one of various bluff failures and problems since the time the rail line was built in about 1910,” Kelleher said. In April 2001, for example, a section of bluff near Eighth Street, which apparently had fill material in it from when the Santa Fe Railroad owned the track, gave way, dropping a 15-foot section of concrete retaining wall to the beach. The North County Transit District authorized money then for emergency repairs.
This latest project by SANDAG, a regional planning agency, arises from an engineering study done in 2001 for the transit district that had suggestions toward adding 20 years’ life to the rail line, Kelleher said. State and federal transportation money is paying for the $3.7 million project, Ruelas said.
As that study recommended, drainage paths were built in 2003 at some bluffs above the track to divert runoff water coming from Del Mar that was flowing into the cliffs and weakening them.
In the latest project, crews will drill 136 holes into the cliffs, most on the western side of the track. The holes will be about 11 feet apart. An I-beam girder will be placed in each to depths ranging from 25 to 60 feet and encased in concrete.
The concrete will have an salmon tint, so that as the bluff erodes the concrete will blend in with the cliffs.
A rope of steel strands, encased in plastic, will be connected at the top of each concrete-encased pillar and reach back and down under the track into the bluff through 6-inch-diameter holes that can be as long as 60 feet. It is, Ruelas said, “almost like driving a nail.”
These angled “tiebacks” help support the weight of the bluff and track to keep large sections from collapsing, he said.
This core work of the project is expected to conclude by about May, Ruelas said.
“The question is, ‘Will it work?’ ” said Del Mar Mayor Carl Hilliard. “I’m not sure we can stop nature from doing it anyway.”
He said neighbors have some apprehension about the inconvenience of having noise and lights at night and also work trucks on the city’s narrow streets.
Some erosion will continue, Ruelas said; by providing the new supporting structures, engineers hope to prevent large sections from collapsing. And if the erosion becomes more serious, he said, the pillars could then be connected with a concrete wall to hold the bluff.
Longer term, Hilliard hopes the rail line would be relocated, with freight and passenger rails taking more interior routes and Del Mar’s bluff corridor perhaps being turned into a scenic recreational path.
Meanwhile, most trains using the route are expected to continue running uninterrupted during the project.
The latest daily Amtrak train, No. 596, that leaves Los Angeles for San Diego at 10:10 p.m. will end its run in Solana Beach. Passengers bound for San Diego stations will board buses in Oceanside to complete their ride south.
Crews will delay the start of work on nights when the Padres are playing at Petco Park to allow the evening Coaster train service from the game to pass through, Ruelas said.