Underscoring the growing urgency to prepare now for rising seas in the decades ahead, the California Coastal Commission is basing its most recent adaptation plan on more extreme scenarios and making the case for relocating vulnerable coastal roads, railways and sewage plants.
Those projections and strategies are drawing a wary eye from some Southern California officials, at least one of whom openly questions the relevance of the commission’s approach.
But the Coastal Commission is firmly defending its draft document, “Critical Infrastructure at Risk: Sea Level Rise Planning Guidance for California’s Coastal Zone.” The report focuses on transportation and wastewater infrastructure, crucial long-term public works that require significant advance planning.
“It’s no longer, ‘How do the tides usually run?’,” said Donne Brownsey, vice chairperson of the commission. “It’s how they’re going to run 30 years from now, 50 years from now, 70 years from now. And it takes 20 years to figure out how to do some of these adaptation projects. The longer you wait, the fewer options you have.”
Evidence of future peril reared its head this month when high tides and big waves flooded parking lots at Capistrano Beach and Aliso Beach. At the same time, Newport Beach scurried to build a protective beach berm on its peninsula. Winter flooding from high seas is already a perennial event in a numbers of coastal towns, including Long Beach and Sunset Beach.
But sea-level rise doesn’t always raise widespread concern among the public because it doesn’t display its threat as dramatically as other disasters, Brownsey said.
“It’s a slower moving crisis than a wildfire or a hurricane,” she said. “But this is an urgent, impactful issue.”
The 224-page draft report was released Aug. 16, with the public and local jurisdictions having until Sept. 24 to submit comments. The commission is expected to consider final approval in November or December.
Extreme forecasts
The state’s Ocean Protective Council, whose predictions about sea-level rise are used by the commission, last year updated its recommendations, calling for state to get ready for 3.5 feet of sea-level rise by 2050. A number of cities had been using — and some continue to use — a benchmark of 6 feet to 7 feet of rise by 2100, although that standard has been criticized for being too extreme because it has been given only 1 in 200 chance of occurring by the council.
The new Coastal Commission proposal, however, uses the even more extreme planning benchmark of 10 feet of rise by 2100, an “extreme high risk” projection that’s considered such a long-shot that Ocean Protective Council doesn’t offer odds of it happening.
Madeline Cavalieri, the commission’s statewide planning director, said the 10-foot scenario was used because of the importance and longevity of transportation and sewage infrastructure, the difficulty of relocating it, and the increasingly dire projections of climate change-driven sea-level rise.
Advance planning for this extreme projection, Cavalieri said, “is a paradigm shift in how we plan for the coast.”
But making plans based on the idea that the ocean might rise 10 feet over the next 79 years may be taking it too far, said Ursula Luna-Reynosa, community development director for the city of Huntington Beach.
“Given the high level of uncertainty around the (extreme high risk) scenario, policy makers need to consider … the significant allocation of limited resources that would be necessary to implement such planning efforts,” she said via email. “Recent studies indicate that the (extreme high risk) scenario may be less relevant for planning purposes.”
Luna-Reynosa pointed to studies that showed high-end predictions of 9 inches of sea level rise by 2050 and 3.4 feet by 2100.
She also took aim at the commission’s preference of avoiding permanent hard armoring, like seawalls, in favor of natural barriers, such as marshes, and relocating infrastructure away from the coast. Seawalls and similar armoring are typically opposed by the commission — especially as long-term fixes — because they can accelerate the loss of beaches and coastal habitat.
“Utilizing high-risk, low-probability scenarios can result in draconian effects if managed retreat and natural buffers are the only tools available,” she said.
Like Huntington Beach, other coastal cities responding to Southern California News Group inquiries said they were still studying the draft document and preparing feedback for the commission.
But even Long Beach planner Alison Spindler-Ruiz, who said the city shared the commission’s sense of urgency and agreed with the analysis that prevailing sea-level rise projections might be underestimates, noted that her city is using “more probable projections.”
Moving roads inland
A 100-year flood combined with 4.6 feet of sea level rise would threaten or damage hundreds of miles of railways, thousands of miles of roads, and at least 28 wastewater treatment plants, according to an analysis cited in the draft report.
Of the five early adaption case studies in the report, three involved relocating existing coastal infrastructure farther inland. One involved moving a 2.8-acre stretch of Highway 1 in north San Luis Obisbo County. Another started with the commission rejecting a plan to rebuild a coastal sewage plant in the city of Morro Bay because of flooding concerns and concluded with approval of a new plant three miles inland.
Additionally, the Orange County Transportation Authority is studying how to address vulnerable beachfront railway in south Orange County and two San Diego County agencies are analyzing possible inland alignments for vulnerable railway in Del Mar.
“In many cases, relocation … is one of the surest ways to avoid coastal hazards associated with sea level rise, as well as the service disruptions and damage that may be caused by flooding and erosion,” the commission report says. “Further, if infrastructure is realigned inland, not only will it be safe, but coastal habitats will have the opportunity to migrate inland and persist as sea levels rise.”
But the strategy known as “managed retreat” often raises hackles on the local level, in part because of coastal homeowners who simply want to shore up their properties with hard armoring such as seawalls and in part because of the expense involved with relocation.
“It’s become a political red flag, even though it’s well accepted as an adaptation strategy,” said Coastal Commission Vice Chair Brownsey. “It’s our effort to take some of the charge out of it so we can have a conversation about a range of adaptation strategies.”
In the the draft report, the words “managed retreat” don’t appear until the references and appendixes, but the words “relocate” and “relocation” appear 77 times. Other possible approaches mentioned in the report include elevating structures and fortifying natural barriers, which can include marshes, as well as burying boulders or cobbles under the beach to stem the ocean’s march landward. Such subterranean revetment has been constructed in Cardiff and is being considered for Capistrano Beach.
Brownsey acknowledged the expense involved — particularly with relocation — while the commission report cites studies saying that every dollar spent early to address vulnerabilities can save $4 to $10 in the long run. The report also lists a host of potential funding sources, ranging from state and federal grants to assessments, utility fees and parcel taxes.
Both Brownsey and Cavalieri said that most coastal cities are already making progress preparing for sea-level rise, and that the public increasingly is aware of the threat.
“But more needs to be done in terms of public education,” Brownsey said. “We have a few communities in Orange County and Southern California that are really resistant to (managed retreat) because it presents tough issues. We want to help people make the best decision and sometimes that’s managed retreat, as difficult as that may be.”
Ultimately, she said, it’s not a matter of controlling the ocean or asserting the commission’s will over local government.
“At the end of the day, we don’t really decide. The ocean decides.”
Vulnerable sites
Among specific Southern California locations vulnerable to sea-level rise and cited in the Coastal Commission’s draft report, “Critical Infrastructure at Risk”:
• “Over 10 miles of railroad track in Los Angeles County will be vulnerable to stormflooding” with 6.6 feet of sea-level rise combined with a 100-year storm, the report says. “In San Diego County, approximately 2 miles of track will be in danger of erosion, and close to 10 miles will be in danger of storm flooding. In some cases, these vulnerable segments represent a significant portion of a city’s shoreline, as is the case for the cities of San Clemente and Del Mar, or are critical to a port as distribution lines.”
• Pacific Coast Highway in Sunset Beach already floods during king tides and “there is potential of widespread inundation across large portions of northern Huntington Beach in the vicinity of Huntington Harbour and Bolsa Chica by 2100” with 5.5 feet of sea-level rise, according to the report. That poses a risk to sewage lift stations.
• “Some areas such as Highway 1 in Huntington Beach and along the Newport coast south of Crystal Cove face erosion threats that will require adaptation planning,” the report says.
• The Orange County Sanitation District sewage treatment plant in south Huntington Beach is vulnerable to tidal inundation, extreme wave events, and storm water runoff.
• “Highways around the Ports of Los Angeles and Long Beach have also been identified as vulnerable to flooding, which has the potential to disrupt extremely valuable commerce. For example, Route 47, Interstate 710, and Highway 1 all merge at the Port of Los Angeles and are exposed to future sea level rise,” the report says.
• The Hyperion Wastewater Treatment Plant in Playa del Rey is about 32 feet above sea level but is still “sensitive to storm-related flooding,” according to the draft report, citing the city of Los Angeles’ own vulnerability assessment. “Significant increases in sea level could reduce the plant’s efficiency in the discharge of effluent because the pumped flow would be met with more water pressure.”