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Beach Erosion, Rising Seas Threaten Amtrak’s Second-Busiest Rail Line

Amtrak’s Pacific Surfliner glides along 351 miles of Southern California coastline, carrying nearly 3 million passengers a year between San Diego, Los Angeles and San Luis Obispo. To the west, riders enjoy sweeping vistas of the Pacific Ocean; on the other side, rolling hills and beachside cities flow past.

But the scenic oceanfront train is increasingly threatened by rising sea levels and severe weather. On Sept. 30, transit officials haltedAmtrak passenger service, as well as Metrolink regional rail, along the nation’s second-busiest rail corridor. After Tropical Storm Kay tore into the Golden State’s seaboard with heavy rains and high tides, geotechnical sensors detected that the fragile landscape of sand and rock underneath the tracks near San Clemente was moving as much as nearly a half an inch a day.

“That is significant,” said Darrell Johnson, the chief executive officer of the Orange County Transportation Authority, which oversees that section of the rail corridor. “We would like to see movements of less than one-tenth of an inch,” he said.

State and county officials declared an emergency and secured $6 million for construction to stabilize the 700-foot stretch of sliding railroad tracks. The plan is to drive large metal anchors into the adjacent slope to prevent it from pushing the track further toward the coast, according to a news release. OCTA is also working with federal and state officials to raise additional funding for repairs; the job is estimated to cost $12 million overall.

An OCTA spokesperson said the agency finalized a contract with a geotechnical firm on Oct. 14, with actual construction work expected to begin later this month. In the meantime, the contractor is finalizing the project design, while 24-hour monitoring of the slope near the track is ongoing. Passenger rail service could be on hold until the end of the year.

The emergency construction comes just one year after the same section of railway was shuttered due to ground movement. In September 2021, Metrolink suspended passenger service for three weeks and placed more than 18,000 tons of boulders, or “riprap,” along the coastal side of the tracks in an effort to protect the line from storm surges.

“The repairs we did last year were envisioned to hold back everything, but that’s all changed,” said Johnson. “The plan we have in place, we believe, will be able to buy some time.”

But how much time, and what long-term remedies can be implemented afterwards, remain “a bit elusive at this point,” he said.

The rail shutdown in San Clemente is just one more illustration of how climate change is reshaping California’s heavily developed coastline, eroding beaches and threatening oceanfront properties and other infrastructure, including the only rail link between San Diego and Los Angeles.

On the East Coast, a similar crisis is unfolding along Amtrak’s Northeast Corridor — the busiest stretch of passenger rail in North America — as rising seas are drowning critical stretches of the track.

According to a recent report from the National Oceanic and Atmospheric Administration, sea levels are expected to rise as much as 12 inches by 2050, leading to more coastal flooding and making tidal and storm surge more severe.

“This most recent example of how climate change is affecting our infrastructure really highlights the severity of the problem,” said Kristina Dahl, senior climate scientist at the Union for Concerned Scientists. “It highlights the need to make some really difficult decisions about the infrastructure that we invest in as sea level rises.”

Coastal erosion tends to be an episodic process. That is, bluffs crumble gradually over time, and then “we’ll see a big chunk collapse,” said Gary Griggs, a coastal geologist at UC Santa Cruz. While the rate of erosion may add up to only a few inches per year, periods of relative stability are typically punctuated by dramatic collapses, or “one big failure,” said Griggs.

“The track is only as strong as its weakest link.”

Roughly 40 miles south of San Clemente in Del Mar, where the railway hugs the edge of oceanfront cliffs, a series of bluff collapses spurred the San Diego Association of Governments, the regional planning agency, to pursue a controversial and costly long-term solution: moving the tracks further inland into a tunnel 80 feet beneath the coastal city. Construction costs for the project could exceed $2.5 billion, and it’ll take more than a decade to complete. In September, SANDAG accepted an expected $300 million state grantto jump-start work on the project.

“The fact of the matter is that we built way too close to the coast, and on top of bluffs,” said Stefanie Sekich-Quinnat, senior manager for Surfrider Foundation’s Coast and Climate Initiative. The environmental advocacy group has been a proponent of the railroad’s relocation for years. Now, Surfrider is calling on officials in Orange County to focus on long-term planning, such as relocation.

The coastal tracks, also known as the Surf Line, date back to the late 1880s, when the California Southern Railroad sought to stimulate economic development in the region. When an older, mostly bypassed section was washed out, the new coastal route became the only rail link between San Diego and Los Angeles. The line’s history has been punctuated by flooding and weather-related disasters: In 1941, a bluff collapse led to a freight train derailment and crash that killed three.

The Del Mar section is one of three at-risk areas where the track rides precariously along the shoreline, the other two include San Clemente and another near Santa Barbara, according to Sharon Humphreys, SANDAG’s director of engineering and construction. Whether the other sections relocate, too, will be up for regional authorities to decide.

“You can't get a train from the border with Mexico all the way up to Santa Barbara, unless the whole line operates,” said Humphreys. “The track is only as strong as its weakest link.”

In light of the recent disruption to train service in San Clemente, OCTA’s Johnson said the agency would “reactivate” conversations around rail relocation, while weighing the community, environmental and economic impacts.

Alternatives to track relocation include the construction of seawalls or other coastal “armoring.” Currently, 38% of the Southern California coastline is armored. But these techniques can end up blocking the natural replenishment of sand and hastening beach disappearance — a phenomenon that’s brought waves perilously close to the Surf Line in several sites. “You need a certain amount of sand in the system for it to work,” said Brett Sanders, a professor of civil and environmental engineering at UC Irvine. “It's like how you can’t run a car without oil in the engine.”

Decades of development patterns have concentrated housing and other infrastructure near the beach: 44% of California’s residents live along the state’s coast. Among high-value oceanfront property owners, the prospect of “managed retreat” — moving people, buildings and infrastructure inland to accommodate sea level rise — can be unpopular, but Charles Colgan, the research director at the Center for the Blue Economy at the Middlebury Institute of International Studies in Monterey, warns that eventually, erosion will make ongoing repairs and maintenance too expensive.

That’s a point that rail transportation officials will have to think about as they weigh their options.

“Disruptions to infrastructure will become more frequent and more prolonged,” Colgan said. “Then you’re looking at a situation like Florida, and what do we do then? It’s a real challenge to fix a lot of little problems.”

This article originally appeared on Bloomberg

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