Heavy Runoff Could Endanger Delta Levee System
KTVU
02/22/2011
SACRAMENTO, Calif. -- In 2006, it took a herculean effort to save Twitchell Island after it was pounded by wind-driven rains and surf.
This was perhaps most recent and dramatic threat to a major delta levee. Since then, years of drought have followed.
But, this winter, high in the Sierra, an above average snow pack waits and the runoff and rising water may test the Delta levees again come spring.
"The high spring runoff is just another event that raises the water level in the delta. It is another place to be vigilant," said California Department of Resources Delta Levee Chief Dave Marass.
Marass said the levee system -- which protects farmlands and communities -- is tested every day by rising and falling tides. As for a significant runoff not seen in recent years?
"The levee system, in general, is in better shape this year because of all the work that's been done on them in the last couple of years," explained Marass.
Dozens of critical erosion sites, or faulty levees, were repaired using huge boulders. One of those repaired levees has become overgrown with vegetation. It protects the low-lying town of Walnut Grove and sits across from Larry Hamilton's home.
"I've lived on one of the islands down here for almost 30 years. Do we worry about it? Are we concerned about it? At times. When the water level gets to a certain point," said Hamilton.
The repairs patched up levees next to communities that could be devastated by a breach.
"But, I got to tell you, they didn't fix the system. Not by any stretch of the imagination. They only put bandages on the system," said Professor Jeff Mount of the UC Davis Center for Watershed Sciences.
Professor Mount says patches to the Delta levee system are not enough but fixing all the levees would be an enormous, if not impossible task.
"A billion dollars of investment in those levees today would raise them about six inches," said Mount.
A heavy spring runoff is just one of many potential threats to the Delta, which provides drinking water to 25 million Californians.
"Whether its a flood. Whether its an earthquake. Or the unlikely case both. The risks are still really high. We can't paper this over," said Mount.
Yet, despite a close call on Twitchell Island and the breach of the Jones Tract Island in 2004, California still does not have a comprehensive plan to respond to an emergency in the Delta.
