Train threatened by rising seas could be saved with a wall – E&E News

California officials will decide today whether to approve construction of a seawall to prevent the rising ocean from destroying a crumbling cliff that supports tracks for one of the nations busiest Amtrak lines.

The vote thrusts the California Coastal Commission into a debate over how to protect the railway carrying 50 trains a day from the effects of climate change. Other proposed solutions include stabilizing the bluff with steel pillars. Theres also a plan to relocate the tracks, a major undertaking thats estimated to cost billions of dollars.

Agency staff have recommended building the seawall at the bottom of a bluff near Del Mar, a beach town where multimillion-dollar houses are threatened by erosion 19 miles north of San Diego.

The railroad runs atop coastal bluffs which are generally 50 to 70 feet high and have a history of landslides and slope failure, said a report by Coastal Commission staff. The proposed project would stabilize areas along the bluffs.

Californias move to protect transportation infrastructure from the immediate effects of climate change comes as roadways, coastlines and residential property around the country face growing risks from intensifying storms, heavier downpours and penetrating ocean waters. The Government Accountability Office warned in a report last month that ballooning disaster costs related to climate change are creating an unsustainable fiscal future.

The federal government alone owns and operates hundreds of thousands of facilities and manages millions of acres of land that might be vulnerable to climate change, the GAO said (Climatewire, May 10).

The debate over the seawall comes as California officials wrestle with how to save the states iconic beaches. A U.S. Geological Survey study in 2017 said rising seawater could destroy two-thirds of all beaches in Southern California if steps arent taken to reduce carbon emissions or adapt to higher oceans.

Already, homes have toppled off cliffs in Pacifica, along bluffs near San Francisco and in Sonoma County. In other beach cities, seawater floods the streets during the highest tides.

The potential approval today would mark a shift for the Coastal Commission, which in recent years resisted permitting many seawalls because they can deplete sand from the beaches in front of them. One of the commissions official missions is to preserve public access to beaches. That has often put the agency at odds with oceanfront homeowners who say seawalls are needed to protect their property.

But the commissions powers are limited in this case, said Laura Walsh, California policy manager at Surfrider Foundation. The San Diego Association of Governments, or SANDAG, a regional planning group, proposed building the barricade to protect the rail line. SANDAG also has sought approval from the Army Corps of Engineers. In addition, the Federal Railroad Administration is providing partial funding for the project. That means all the commission can do is rule whether the proposed seawall is consistent with the California Coastal Act, a beach protection law, Walsh said.

More than 50 trains a day travel on the tracks that curve along the Southern California coast, offering panoramic views of the Pacific Ocean. But the bluffs are crumbling as higher waves chew away at the base of cliffs. Flooding on the tracks has forced local authorities to stop or slow trains repeatedly (Climatewire, Dec. 2, 2019).

The threatened track carries the second-busiest Amtrak route in the country. The train linking San Diego with Orange County, Los Angeles, Santa Barbara and beyond transported 841,000 passengers last year, trailing only the Acela line that connects Boston with New York and Washington. A local commuter line, a freight company and the military also use the California tracks.

The proposed seawalls would be linked to other barriers installed during emergency repairs to the tracks. All together,, the seawall would cover approximately 2,500 feet and stand 7 to 8 feet above the ground, the Coastal Commission report said.

Local communities are objecting to the project. Del Mar residents argue it would cut off beach access for residents, said Terry Gaasterland, a Del Mar City Council member.

It also would cause beach erosion, she said, as waves carry off sand in front of the wall. In other locations where seawalls were used, such as in the Chesapeake Bay, she said rocks, or riprap, eventually must be placed in front of the wall to cover a gap created by wave action.

Over a 30-year period, these walls are going to become this horrible thing, Gaasterland said. They have to reinforce with riprap at the bottom of the wall. You know more sand goes away. Its just this negative feedback loop.

The staff recommendation to allow the walls includes several conditions, including that SANDAG remove the walls and restore the bluff in 30 years. That presumes that the tracks would be relocated.

SANDAG wants to move the tracks by 2035 but currently lacks the estimated $2.3 billion needed for the effort. SANDAG also hasnt settled on a location for moving the tracks (Climatewire, Jan. 25).

Hasan Ikhrata, CEO of SANDAG, said the group hopes to get $250 million to $300 million from the state to fund environmental review and design for moving the train.

Some Del Mar residents also argue the seawall would ruin the appearance of the craggy natural bluff for at least the next 30 years, potentially harming its ability to attract visitors. More than 3 million tourists visit the city annually. The average price of a home in the area is $3.7 million, according to Zillow.

Instead of a seawall, Del Mar advocates want to use soldier piles, or vertical steel beams drilled into the ground, to support the train tracks.

Ive been told that engineering wise, the soldier piles are the most stabilizing thing that can be done that thats actually the thing thats the safest for the tracks, Gaasterland said.

Ikhrata said the soldier piles alone wont suffice.

We dont think the piles by themselves are going to stabilize the bluff and make it safe for us, he said. To stabilize the bluff and keep the trains moving at the speeds they are, we do need to do both the piles and the seawall.

Coastal Commission staff argues that using just soldier piles would require more excavation and alteration of the bluff face, the report said. As such, it would be more difficult to remove the development and restore the bluff to a more natural condition once the tracks have been relocated, as compared to the proposed seawalls and surface stabilization.

Del Mar has tangled with the Coastal Commission previously. It was one of the first local governments to say it wouldnt accept efforts to plan for managed retreat, the idea of removing structures along the shore so the ocean can migrate naturally.

Many oceanfront homes in the community have seawalls. Those have been allowed for the most part because the houses were built before 1977, when a beach protection law known as the California Coastal Act made it more difficult to build barriers.

Gaasterland, the City Council member, said those walls are well above sea level, and therefore dont contribute to as much beach erosion as the proposed wall for the railroad tracks.

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Train threatened by rising seas could be saved with a wall - E&E News