By Bob Walsh
Water spills from a levee break in the White Slough area northwest of Stockton in January 2017
The California Delta is in many ways physically fragile.
There are about 1,100 miles of levees there. A lot of those levees
were not engineered in the first place and are over 150 years old. They
are often maintained, which is to say not maintained, by a large number
of underfunded reclamation districts. Sometimes work is available from
the Army Corps of Engineers and sometimes money is available from the
state or from FEMA. That money however is often both meager and slow to
arrive.
Last year a levee
around Victoria Island threatened to fail. Had it gone it would have
required that the pumps moving water to SoCal be shut down, probably for
weeks, until the backwash of salt water from the bay had subsided.
They managed to stop the leak by pounding sheet piles into the levee.
It worked, and it was expensive. And according to Jeffrey Mount, a
geomorphologist who is an expert on the problem, said that the Victoria
Island levee was one of the better ones in the delta.
The
Delta levees are functionally in many ways more like dams in that they
are exposed to water pressure constantly rather than just for a few
weeks or months per year during high water events. This makes the area
more vulnerable to flooding according to hydrologists.
The
state cut back on levee maintenance from the current year budget. It
is unclear what will happen next year. For those of us who live in the
area it could get interesting. I am personally at 30 feet elevation
above mean sea level and I have flood insurance, but it is still a
little bit scary. Water is powerful. And unforgiving.
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