More rock for LACMA, please

Posted on | May 22, 2012 | 4 Comments

The Los Angeles County Museum of Art compares the Levitated Mass to the construction of the Pyramids. After captivating the world’s press by parading the 340-ton boulder from Riverside to mid-city Los Angeles last winter, the latest news is that the museum is about to officially declare its rock open for visitors. Irony of ironies, just as our collective gaze is once again drawn toward this $10m publicity stunt, roughly 20m cubic yards of the kind of rock that can’t be levitated has built up around the headwaters of LA’s paved rivers. In contrast to the Levitated Mass, it’s not getting much press while the infrastructure that holds it can and should rightly be compared to the Pyramids. This is the flood control system of 14 dams and 162 debris basins that form what historian Jared Orsi describes as “a Maginot line” between the San Gabriel Mountains and the Los Angeles basin. It is the product of the headiest days of 20th century engineering, in part the work of General George Washington Goethals, the man who oversaw construction of the Panama Canal. And this flood control system on par with the Panama Canal and Pyramids is failing.

Sediment behind the Santa Anita Dam, whose construction was overseen in the 1920s by General George Washington Goethals, the engineer responsible for the Panama Canal. Photo: Emily Green

With the benefit of hindsight, the wonder is that anyone ever thought it would work. Fire-scarred slopes of gyrating mountains send millions of tons of sediment toward this Maginot line every rainy season. This tide is only intensifying after the Station Fire burned a quarter of the Angeles National Forest in 2009. A recent estimate put the backlog of rock and sand in our flood control system at enough to fill the Rose Bowl 50 times, with another hundred and ten Rose Bowl’s worth expected to slide our way out of the San Gabriel Mountains in the next twenty years.

And it will just keep coming. The San Gabriels are a young range, rising by some estimates two inches a year. The rock and sand that they shed as they grow is what formed the LA Basin in the first place, along with its riverbanks and beaches. Since we’ve dammed our rivers and built out the flood plain, the crushed granite carried out of the mountains by winter rains can no longer flow downhill to the Pacific. Rather, we have to catch this sloughed-off rock, by the stadium full, in the foothills.

What can be done with it? If it’s not allowed to be carried by rivers, the most sensible and least likely measure to be adopted, it has to be trucked (or “levitated” if you prefer the LACMA poseur term for trucking.) The cleaning out of one debris basin alone might require 200 trucks a day every day for two years. Quite often, with Sisyphean lunacy, Public Works trucks this truly massive mass back uphill, back into the mountains that form the Angeles National Forest, where Los Angeles County operates 11  sediment dumps and will undoubtedly be looking to open more. Or the trucks might head to lower elevation wild canyons, where many acres of oaks and sycamores are targeted to be bulldozed to make way for sediment dumps. Or this phenomenal tide of ground rock might be drained and stacked in wedding-cake-shaped mounds in ravines behind million dollar homes.

Until recently, the choice of stashing place was made by a relatively closed circle dominated by Flood Control engineers. Since the felling of 11 acres of pristine oak woodland in Arcadia for a sediment dump sparked outrage among LA’s small but passionate network of wild land conservancy groups in early 2011, where to store this infinite supply of sand and rock has gained a public forum. The comment period of a 15 month Public Works study on options closes on May 30th. The renewed hype about LACMA and its “levitated” rock has given me a wonderful idea. We should have a sediment dump on the lawn of LACMA! Then they would indeed have something that would legitimately beg comparison to a Pyramid.

Emerging sediment dump in Arcadia, California being topped up by a Public Works frontloader. Photo: Emily Green





4 Responses to “More rock for LACMA, please”

  1. Jessica
    May 22nd, 2012 @ 4:53 pm

    well said. And to drive the point home a little further, each canyon that is filled includes a stream – that is or will be buried. (same is true of many of our landfills) The flood system deadened hundreds of miles of streams in the lowlands, and now threatens to take out streams in our forest lands – for something that naturally wants to roll downhill. That should give us all pause.

  2. Leigh Adams
    May 22nd, 2012 @ 7:52 pm

    An elegant piece on a subject we need all be mightily concerned about. The Engelmann Oaks were felled to dump sediment. How tragic and dismaying that a city that can transport a rock for no apparent reason can not look at the particles that flow downstream with the same creative imagination. Levitate indeed!

  3. John Bass
    May 23rd, 2012 @ 9:28 am

    If anyone’s interested in further reading, there is the chapter in John McPhee’s book The Control of Nature called “Los Angeles Against the Mountains.”

  4. EmilyGreen
    May 23rd, 2012 @ 9:34 am

    There is indeed. It may also be found through a link at the New Yorker, where it was part of a landmark series in the 1980s and what may be McPhee’s greatest work, though that’s a hard call to make:
    I recently wrote about the issue for High Country News.
    Both places have pay walls, and both are worthy of earning subscribers. The HCN piece may be read by taking out a free thirty day trial subscription.

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