San Francisco’s Levee System Is Defeating

San Francisco’s Levee System Is Defeating

Building with nature: Can reviving a marsh save this California town from sea level rise?

by The Sacramento Bee, Published April 22, 2017

This story is part of a series on how climate change is hurting California. Read the rest of the series here.

From the outset, this small inland town was built to withstand the ravages of the next big California earthquake. Its design allows the region’s levees to hold up during a quake even if a flood comes along.

Yet the levees, built a century ago, are weakening. The levees that protect San Francisco from the kind of disaster that destroyed this town, which was in danger of being washed out by the sea, are also deteriorating.

“If there were a major earthquake today, we would likely not survive,” said Steve Van Deventer, a geotrainer with the San Francisco Department of Public Works. “And with less water to hold back the floodwaters, our levee system would fail.”

In the early 1900s, San Francisco was under siege from a series of floods. In response, the city’s leaders began planning for a new, massive system of levees.

San Francisco levee system: A century-long, $1.7 billion project

In the midst of San Francisco’s flood crisis, city leaders launched the San Francisco levee protection project in 1911. They started with a modest $1.7 million, and grew it to become one of the largest engineering projects in the west. When it was finished in 1915, its cost had topped $12.5 million.

Now, San Francisco is in a race against time to raise the height of the levees to keep them from failing in a major flood, like the historic 1906 catastrophe that killed more than 200 people and destroyed about 1,600 buildings. To keep the project going, the city is looking for ways to help the marshlands along the bay coast, where water management has long been an issue.

During the height of the San Francisco flood of 1906, about one-fifth of the 569-square-mile bay was underwater. What’s more, the massive, 3- to 5-mile long waterway, once the largest in the world, is still flooded at high tide.

Some scientists say that water table levels are rising, not because of climate change, but because of what happens

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