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Erosion at Ocean Beach could send sewage into the sea 

Wednesday, Jan 26 2011

San Francisco is renowned for bad public infrastructure pro-jects such as the $1 billion Central Subway to Nowhere, or the overdue, overbudget, and untested $7 billion eastern Bay Bridge rebuild.

But no local facility seems quite so shitty nowadays as the Oceanside Water Pollution Control Plant in the Sunset. That's the one jokesters proposed naming after George W. Bush. It seemed like a great idea when it was built in 1993. The $200 million plant and its accompanying storage culverts have a capacity of 65 million gallons in wet weather. Where storms used to cause sewage overflow to the ocean around 70 times per year, there are now only seven such incidents. It was named the EPA's plant of the year in 2004.

But the plant was built in an unfortunate spot. Erosion has eaten as much as 70 feet of shoreline in recent years. It is now only about 100 feet from a stretch of cliff made up of old, soft landfill that is rapidly vanishing. It has come as close as 30 feet to the culvert. If erosion carved underneath the water treatment plant, and concrete began to sag and crack, raw sewage could run unhindered into the sea.

Environmentalists insist San Francisco should solve the problem by moving the plant. But that would cost billions of dollars, which the city doesn't have. The Department of Public Works insists that the shoreline must be hardened, even at risk of accelerating beach erosion.

Last year, the city declared an emergency, closed the Great Highway in front of the plant, and spent more than $2 million dumping boulders on the shore. We get one of these "emergencies" every time there are major storms.

"The city is stuck in a reactive mode, and there have been emergencies several times now," says Ben Grant, a consultant with San Francisco Planning and Urban Research (SPUR), which has obtained $400,000 in grants to study ways to improve Ocean Beach. "There isn't a policy in place."

But while San Francisco may be a city of querulous residents and do-nothing politicians, we also happen to be lucky.

In the case of the Ocean Beach erosion problem, two visionaries — one a federal engineer, the other an academic economist — have independently come up with a solution that may give us a renewed beach, an intact sewage system, and a preserved highway. It involves taking sand already dredged from the Golden Gate shipping channel four miles offshore and repeatedly dumping it near the shoreline. It's a scientifically effective and economically viable way to allow natural wave cycles to replenish sand, slow erosion, and thus avoid tough tradeoffs.

However, officials, planners, and activists working on the Ocean Beach problem didn't, at press time, seem to realize their problem was on its way to being solved.

Peter Mull, a square-jawed outdoorsman, speaks with the precise diction and technical terminology of an engineer, interspersed with a dedicated surfer dude's exaltation at the beauty of a perfect curl. "If you have an absence of sand, the beach gets denuded, and offshore sand bars are eroded, and lost," the dredging project manager with the Army Corps of Engineers says. "Then nature doesn't have what it needs to shape those glorious waves offshore that we need."

During the late 1990s, when Mull was working in private engineering practice, he joined with surfers and other beach preservationists to address San Francisco's erosion problem. For a century, the city's western shoreline had served as a dumping ground for rock, dirt, and other landfill. During the 1990s, the city bolstered the Great Highway and built parking lots along the oceanside bluffs there.

But over time, a landfill has been no match for a turbulent ocean. The city has periodically hardened the seawall with cement blocks and boulders. But that can make matters worse, because waves hitting a hard, vertical surface tend to drag sand out to sea.

Mull had an idea for a third way. He knew that bay currents deposit sediment onto a shallow sand patch four miles offshore. Every year the federal government dredges a trough through it for ships and then dumps the sediment into deep ocean. Mull suspected that if that sand were deposited just off Ocean Beach, it would replenish material that storms sweep away. "It's like putting blood in veins," he says. "Once that extra sand is in the system, the sandbars and beach can form properly." Further, if the Corps of Engineers created dunes by piling more channel sand west of the sewage plant, they might deter the landfill erosion.

In 2001, Mull was hired by the Corps of Engineers to work on an unrelated wetlands project and started bugging colleagues about his idea. In 2005 he got the Corps to begin a sand-dumping pilot project at Ocean Beach, which he runs. Now, he's obtaining permission to use more channel sand to build his dunes. If he can get the city to contribute part of the $2 million or so cost, and if he can also obtain environmental approvals, Mull hopes to commence in 2012 or 2013. Given that his approach seems to satisfy all sides, this might be a rare approval process that doesn't bog down.

At around the time that Mull was pushing his plan, SF State assistant professor Phil King was pioneering the field of shoreline economics. King assesses the economic value of sandy urban beaches. And why not? Millions of people pack picnics, don swimsuits, and "consume" them. He combined his analysis with assessments of built property nearby, and estimates of costs for battling erosion. He has advised cities up and down the West Coast, but not San Francisco. Nonetheless, in February, he will release an independent research paper that applies his analysis to beaches in Monterey and San Francisco. "We have found nourishment, which is adding sand to the beach, can be an effective way to mitigate against storm damage and sea level rise," he says.

King identified Mull's technique as the most cost-effective way to solve San Francisco's erosion problem — but nobody in charge seems to know this. It might sound anti-intuitive at first. Isn't it a bit like trying to plug a leaky bucket by pouring water into it? But it's actually more like protecting a house from the weather with periodic coats of paint. Beach erosion cycles tend to calm down after enough sand is added to create offshore sand bars and on-beach bluffs.

SPUR had not incorporated King's research into the Ocean Beach master plan project when I spoke with Grant last week. Mull hadn't talked with him either.

Instead, San Francisco has merely been fortunate that an academic expert independently took on the task of confirming the viability of this win-win solution.

In the future, San Francisco will doubtless build more stupid infrastructure. People will bicker endlessly. Politicians will close their eyes.

Myself, I'll pray that somehow residents step up with solutions and we stay lucky.

About The Author

Matt Smith


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