Calif. Quake Could
Devastate Water Supply
November 03, 2005 — By Don Thompson, Associated Press
SACRAMENTO — A major Northern
California earthquake could severely damage the Sacramento-San Joaquin
Delta levee system and jeopardize the water supply for two-thirds of
Californians for more than a year, a top state water official warned
Tuesday.
Last year, the unexplained collapse of a single levee shut water pumping
for days and cost $100 million to repair. An earthquake could lead to
the collapse of many sections of levees, which channel Northern
California rivers on their run to San Francisco Bay, said Lester Snow,
director of the California Department of Water Resources
"This is not a worst-case scenario," he said. "We think it's a plausible
scenario of what could happen in the delta."
Snow told a joint hearing of three state Senate committees that a
6.5-magnitude earthquake could collapse 30 levees, flood 16 delta
islands and damage 200 miles of additional levees. Some 3,000 homes and
85,000 acres of farmland would be flooded.
The ruptured levees also would allow salt water to rush in to the river
system, causing an immediate shutdown of the pumps that send water south
to San Joaquin Valley farmers and Southern California water districts.
Cities would have to use alternative water sources and resort to
rationing, Snow said.
Three state highways and railroad tracks would be submerged, and
petroleum and natural gas pipelines would have to be shut down. Damage
could reach $30 billion over five years, Snow said.
It would cost $1.3 billion to strengthen 500 miles of delta levees so
they are not subject to erosion in a flood, but even that would do
nothing to make them more resistant to earthquakes, said Leslie F.
Harder Jr., the water resources department's acting deputy director for
public safety.
Among the possible long-term fixes are flooding some islands that are
surrounded by levees. Flooding would equalize water pressure on the
islands, making a levee collapse less likely.
Despite the warnings, no delta levee has collapsed because of an
earthquake, said Thomas Zuckerman, general manager and co-counsel of the
Central Delta Water Agency. He said strengthening levees around just
three islands at the mouth of the delta could reduce 70 percent of the
risk.
Lawmakers said there is not enough money for significant levee
improvements. State tax bonds would be needed to make the necessary
repairs, said state senators Michael Machado, D-Linden, and Tom
Torlakson, D-Antioch.
Source: Associated Press
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