San Joaquin River DOTMDL -- Technical Working Group

Experts say floods are likely, plan to live with them

Chico Enterprise-Record - March 05, 2005
By Heather Hacking

Experts say floods are likely, plan to live with them
Chico Enterprise-Record 3/5/05
By Heather Hacking, staff writer

Reining in the rivers in the Sacramento Valley
has been a decades-long battle, a fight that is
costly and bound to fail, experts said at a
conference about flooding held in Chico Friday.

When settlers came to the valley in the early
1800s, the valley floor was a massive flood
plain, explained Irv Schiffman, chair of River
Partners, one of the sponsors of the program. The
inland sea didn't drain until summer. Changes to
the river meander deposited sediment that made
rich soils.

Over the past five decades, systematic efforts
have been made to tame the river with levees,
weirs and bypasses. Now every major river in the
valley has dams.
These efforts have kept things in check, for the
most part, but big floods hitting Northern
California are to be expected, Schiffman said.

Stacy Cepello, of the Department of Water
Resources in Red Bluff, said California is
periodically hit with "major-league storms,"
usually coming from the tropics.
Removing vegetation that acts as a sponge for
floodwaters and paving over land means more water
through the river systems, Cepello said.

Disruption of the natural flows began in the
1850s during the gold-mining era and reached a
peak with hydraulic mining.

"The scale to which this happened is unbelievable," Cepello said.

In the Feather River, for example, 2 million
cubic yards of sediment went down the waterway in
a year. During mining, up to 1.2 billion cubic
yards washed downstream. Sacramento began to have
a chronic flooding problem. The Army Corps of
Engineers was overwhelmed and redesigned the
system. The Sutter and Yolo bypasses were built
to handle high flows and dams were built. Shasta
Dam, for example, has reduced floods by about
half, Cepello said.

Tom Griggs, of River Partners, discussed the
habitat that relies on land near waterways to
survive. Root systems of trees along the banks
can help stop erosion, he explained.

The common yellow throat bird lives in cattails
and woody vegetation and needs 2-3 feet of water.
The black-headed grossbeak needs woody vegetation
near wetlands. Bank swallows nest only in banks
that are eroding. Song sparrows prefer
herbaceous, weedy edges near water, habitat that
is rapidly declining, Griggs said.

Swainson's hawk requires tall trees for nesting
and needs grasslands to hunt small mice and
crickets. Yellow billed cuckoos are found only
with open water and currently there are only
40-60 pairs in the Sacramento Valley, Griggs said.

Jeffrey Mount, of the department of geology at UC
Davis and a member of the Reclamation Board and
Science Board with CalFed, said the nation has
tried to eliminate flood plains, but has been
unsuccessful.

The system tries to move water quickly, but this
has tremendous biological and economic
consequences, Mount said.

The national flood insurance system was created
to map out what areas are likely to flood and to
require flood insurance in those areas. The
decision was made to designate areas as either in
the 100-year flood plain or outside the 100-year
flood plain. This decision has driven hundreds of
billions of dollars of growth, "but it's all
wrong," Mount said.

"We have a distorted policy to put rivers inside
levees," he said. But the 100-year flood maps are
an assumption that the rivers won't flood for 100
years.
There are only 60 years of flood records to go by, he said.

The spiral of building more levees and dams just continues, he said.

Scientists agree that climate changes are
occurring. Because California gets half of its
water supply from snowpack, a warming trend could
wreak havoc on the state's water system.

"Yet we're building whole cities and sewage
treatment plants" and other infrastructure in
areas where high water will eventually occur,
Mount said.

Natural flood plains are the best storage for
floodwaters, Mount said. The deposit of river
material improves soils for farming, he added. #
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