The Sacramento Delta: A Gordian Knot - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 209

At the Banks pumps, Delta water flows into the Clifton Court Forebay, through a set
of fish screens (which are supposed to keep fish away from the pumps), and finally into
the pumps, which shove the water 245 feet up a hill and into the California Aqueduct.
The aqueduct carries the water 444 miles south, to the Perris Reservoir between Los
Angeles and San Diego. It is a magnificent system for moving water, but the pumps are
at the heart of a long, bitter controversy over the Delta.
Inside a metal shed, eleven thundering pumps were lined up in a row, the largest
of which use eighty-thousand-horsepower engines. “With everything working, we can
move 6.7 billion gallons of water per day , ” said our guide, Doug Thompson. The State
Water Project is the single biggest user of electricity in California. Prices are cheaper
at night, so the temptation is to do most of the pumping then. But the Delta smelt,
Hypomesustranspaciicus—a small, silvery fish endemic to the Delta that is listed as
threatened—prefers to spawn at night, along the channel's edges. In an effort to prevent
the fish from being sucked into the pumps' spinning impellers, the Banks plant is mostly
run during the day.
Smelt live for about a year, travel in schools, feed on zooplankton, and are an “indic-
ator species,” meaning that they act as a natural gauge of the health of the ecosystem.
Delta smelt were once one of the most plentiful fish in the estuary, but the Banks and
Tracy pumps have been blamed for pulverizing millions of smelt and pushing the fish
close to extinction.
Upstream from the Banks pumps, the John F. Skinner Delta Fish Protection System
is basically a giant screen that, according to the DWR, diverts an average of 15 million
fish a year away from the pumps. The facility consists of an intake channel, a series of
V-shaped, louvered blue gates that push away or collect smaller fish, and holding pens
for fish. Once enough fish are gathered, they are loaded into silver tanker trucks, which
take them to a release point near Antioch.
“ he system is efective but not lawless ,” notes a DWR pamphlet. Not only do the
smelt get into the pumps, but big fish and sea lions have figured out how to corral them
near the screens and gobble them up.
I could see that Gleick, who had remained preternaturally calm as we toured the
pumps, was growing agitated. Back in the Prius, he vented about the pumps and the fish
screen: “This thing is the Achilles' heel of the whole Delta system! It's what an engineer
would design to move water efficiently, which it does very well, but it doesn't screen fish
well at all.”
The pumps were built in the 1960s, when DWR's mandate was to supply water. But
water managers now have to satisfy a much broader set of needs, including the ecosys-
tem's. “The world has changed,” said Gleick, “but the infrastructure hasn't.”