For years, San Francisco's Ocean Beach has been under assault by such powerful surf that a fierce winter storm can scour away 25 feet of bluff in just days.
The startling pace of the erosion near the San Francisco Zoo has compelled the city to spend $5 million to shore up the crumbling bluffs. The strategy has been simple: drop huge rocks and mounds of sand to protect the nearby Great Highway and the sewer pipes underneath from being destroyed by the crashing waves.
But as the enormous rocks have piled up, adding to a jumble of concrete — chunks of curb and bits and pieces of gutters — from parking lots that have tumbled onto the shore, so too have the demands that the city get rid of it all and let the coastline retreat naturally.
Now, San Francisco finds itself under fire from environmentalists, who call the rock and rubble unsightly and harmful to the beach, and the California Coastal Commission, which regulates development along the state's 1,100-mile coastline but has refused to sign off on the fortifications, some of which have sat on the shore for 15 years without its permission.
The standoff at Ocean Beach is the face of the fight in California over the proliferation of sea walls and tossed-together barriers, steps that environmentalists and others say are obliterating the state's beaches and will never stand up against the advancing ocean.
"It's like a post-apocalyptic war zone out there, and nowhere else would you allow it," Mark Massara said of the heaps of rock and concrete at Ocean Beach. Massara is a local resident and an attorney for the California Coastal Protection Network, an environmental group that has filed suit to force the city to remove the rock.
"My concern as a surfer that lives on Ocean Beach is that I'm going to die before these people ever remove all this stuff," he said.
City officials say they can't simply let the sea have its way. They've removed some debris, but pulling out everything would put the roadway and vital infrastructure underneath at risk.
"If you remove the rubble, how much more rapidly is the erosion going to occur?" said Frank Filice, manager of capital planning for the San Francisco Department of Public Works. "Actions have to be done very incrementally. In the meantime, the rubble has a purpose — not a very attractive one — but it does provide protection."
The dispute over how to respond to the receding shoreline south of the Golden Gate Bridge is similar to others playing out at wave-battered bluffs and beaches up and down the coast, where temporary sea walls have a way of becoming permanent fixtures.
An emergency coastal permit like the one San Francisco used to build one of its sea walls can be obtained over the counter from the Coastal Commission, allowing property owners to quickly erect a temporary barrier in the face of severe winter storms.
But when the cranes and bulldozers leave and the storms pass, the sea walls have a way of sticking around, sometimes for years.
On crumbling bluff tops from Pacifica in Northern California to Encinitas in San Diego County, homes are protected by large rock sea walls and sandbags that were allowed under emergency permits but have never been formally approved. In Cayucos, a beach town in San Luis Obispo County, some oceanfront homes are protected by nearly 30-year-old sea walls that received nothing more than verbal authorization. Other coastal highways in the state are protected by sea walls that were supposed to be temporary.
The 1,000 feet of rock sea walls at the center of the dispute in San Francisco were not supposed to be permanent either. Some were built with emergency permits and some without any permission from the Coastal Commission.
In July, the panel rejected San Francisco's bid for after-the-fact approval for the barriers and get permission to build several hundred feet of new, buried sea wall. The commission said the city needed to come up with a better plan, such as moving back from the shore or building a vertical structure mimicking a natural bluff.
San Francisco shot back, suing the Coastal Commission in September in an effort to void its decision.
Ocean Beach, part of the Golden Gate National Recreation Area, is not for the casual swimmer because of its chilly water and violent surf. But the urban beach gets about 2 million visitors a year, and the eroding section south of Sloat Boulevard is popular with hard-core surfers because of its huge swells.
Twice, the waves have been brutal enough to pose a threat to underground infrastructure, city officials said. The El Niño-stoked storms of December 2009 and January 2010, for instance, devoured more than 40 feet of bluff, undermined the Great Highway and sent its southbound lanes sliding into the surf.
San Francisco's reliance on crude sea walls isn't out of the ordinary in California, where property owners for decades have erected fortifications when waves threaten homes, roads and underground sewer lines.
The result: More than 10% of the state's coastline — and about one-third of Southern California — is protected with man-made barriers.
Although sea walls effectively protect property in the short term, they can intensify the effect of waves and alter surf patterns, leaving beaches stripped of sand until they narrow or even vanish altogether.
Environmental and surfing groups strongly oppose the barriers, and coastal regulators have increasingly asked property owners to find other ways to cope with the ocean.
There are some signs San Francisco is moving in that direction.
Last month the Coastal Commission granted the city an emergency permit to drop large sandbags on a length of the beach in preparation for this winter's storms, a softer approach on the city's part that even drew praise from a member of the local chapter of the Surfrider Foundation, an opponent of sea walls.
A master plan being drafted for the beach calls for moving the most pinched stretch of the Great Highway several hundred feet inland and narrowing the road in other places.