Managed Retreat

Managed Retreat

Joe Eaton

Download: Estuary News, February 2013 PDF

Call it the Canute Syndrome, after the 11th-century monarch who is said to have ordered the waves not to approach his throne. In the past, when storms and waves eroded a heavily-used California beach, the automatic response was armoring the shoreline—putting down boulders, building revetments or groins. That’s changing, though, due to a constellation of forces: nonprofits like the Surfrider Foundation advocating for natural beaches; engineers willing to take on projects that build shoreline resilience; Coastal Conservancy funding to implement them; a Coastal Commission majority unwilling to approve hardscape solutions; and the certainty of sea level rise. From San Francisco to Ventura, a new consensus is emerging that the soundest approach to beach erosion is to step back, even if that means relocating infrastructure. The strategy is “managed retreat,” a phrase coined by ecologist Reed Noss of the University of Central Florida with reference to habitat corridors for wildlife.

Our coastline is “a temporary line in the sand,” writes Gary Griggs in Introduction to California’s Beaches and Coast.  We’ve ignored its temporary nature by building out onto the beach. Bob Battalio, an engineer with ESA PWA involved with several managed retreat projects, points out that sea level has been rising over the last 20,000 years, cutting into low landforms: “We shouldn’t be surprised if the shore encroaches upon what we build. It’s hard to stop this large-scale geologic process even if you own the property. When we try to intervene and manage the system, we end up with man-made problems. We’re throwing public money off the cliff to try to maintain something that’s ultimately not sustainable.”

The master plan for San Francisco’s Ocean Beach, developed by the San Francisco Planning and Urban Research Association (SPUR) incorporates managed retreat. Not yet officially adopted by the city, its goals include dismantling the Great Highway south of Sloat Boulevard, letting dunes migrate inshore, and restoring native dune vegetation. “Closing the Great Highway is a spectacular move,” says SPUR’s Ben Grant. The plan took shape after the Coastal Commission rejected further shore armoring. SPUR brought together stakeholders like the Golden Gate National Recreation Area (GGNRA), S.F. Park & Rec, the S.F. Public Utilities Commission, Surfrider, and Golden Gate Audubon, and won across-the-board political support. It’s not all retreat: the sewage treatment plant will be protected by a dynamic revetment. “We worked hard to get out of the framework of armoring versus retreat,” Grant adds. “It’s a careful combination of managed retreat, beach nourishing, and selective armoring. We came in from the outside without a dog in the fight and made people acknowledge each other’s constraints.”

The regulatory constraints associated with the plan are formidable, including wastewater permits under the Clean Water Act, state and regional water board permits for federal dredging, Coastal Commission coastal development permits allowing emergency armoring and future management activities, and GGNRA permits for activities on a national park property. In addition, two sensitive bird species use the beach: snowy plovers winter in the central and northern portion, bank swallows nest in the  bluffs south of Sloat. Under the master plan, the plovers would benefit from dune habitat restoration. “The bank swallow habitat is one of the major constraints that has regulatory teeth,” says Grant. “A lot of the embankment is artificial fill, not really good nesting habitat, which we propose incrementally removing.”

Pacifica State Beach, post construction, 2005. Photo courtesy City of Pacifica
Pacifica State Beach, post construction, 2005.
Photo courtesy City of Pacifica

Down the Peninsula at Pacifica State Beach, managed retreat entailed relocating a parking lot and a bike path, rerouting access roads, and demolishing two homes. “The main problem was a lack of trust,” recalls Battalio. “The city had a varied record, with a lot of armoring in the northern part of town.” When funding constraints killed a proposed cobble berm, ESA PWA came in with a design alternative. “It’s an ongoing process,” he says. “We moved back 40 feet and we’re good for 20 or 30 years. Then we have a problem about what we do if sea level rise really accelerates.”

Santa Barbara has a long history of attempted erosion control at Goleta Beach, with rock revetments emplaced, removed, then reinstated. The city proposed a $20 million sand-trapping groin to stabilize the beach and found a Southern California engineering firm to build it. Surfrider and the local Environmental Defense Center (EDC) argued that this would cause downcoast beaches to narrow as much as Goleta Beach would widen. Despite support from a group called Friends of Goleta Beach and local politicians, the Coastal Commission voted down the groin plan. “It was a tremendous victory,” says EDC’s Brian Trautwein. “Immediately afterward we started talking with the county about a managed retreat approach.” That led to the Goleta 2.0 plan, with Phase 1 construction budgeted at about $3.5 million.  The plan will remove a parking lot at the beach’s erosion hot spot, squeeze out more spaces in another lot, move sewer and water lines and a bike path inland, and build a dune system on geotextile bags.

“Surfer’s Point,” Ventura.
Photo courtesy City of Ventura and Rasmussen Construction.

Consensus came more easily with the Surfer’s Point project in Ventura, where the Coastal Commission denied a permit for a rock revetment. According to UC Santa Cruz researcher Marc Beyeler, the key figure was Surfrider activist, city councilman and restaurateur Brian Brennan, who restarted a stalled process by bringing stakeholders together at a “Caesar Salad Summit.” As with Pacifica, a bike path and parking lot were moved back. “Surfer’s Point is a leading example cited by federal and state agencies,” says Beyeler. He believes social scientists should investigate ways to generate this kind of community support for adaptive shoreline management: “Even if we have the best natural science, the real limitation is the disconnect between science and policy.”

Beyeler feels the “managed retreat” concept needs rebranding, preferring “resilient shorelines.” ESA PWA’s Battalio agrees that “retreat is not a popular word. Lots of people are calling it realignment. But I use ‘retreat’ because it’s important to communicate with people. We’re going to retreat. The only question is how much money we waste and how much of the environment we destroy before we figure that out.”

NOAA: Ocean and Coastal Resource Management
SPUR: Future of Ocean Beach

CONTACT: Bob Battalio, [email protected]; Marc Beyler, [email protected]; Ben Grant, [email protected]; Brian Trautwein, [email protected]