Wednesday, March 16, 2005
By Lauren McSherry, Town Crier Staff Writer
Just about anyone who has
taken a flight out of
an airport in the Bay
Area and glanced out a
plane window has seen
them. Thousands of feet
beneath a plane, the salt
ponds look like patches
of bright red in a mosaic
of levees, highways, industrial
parks and residential
neighborhoods that make
up much of Silicon Valley
- all in close proximity
to the blue waters of
the San Francisco Bay.
The salt ponds, which ring
the entire South Bay, from
the San Mateo Bridge on
down, get their unique coloring
from the evaporation process
of salt making. Red ponds
have the highest salinity
levels compared to dark
blue or aquamarine salt
ponds.
Recently, a
coalition of government
agencies and environmental
groups embarked on a project
to restore the ponds, once
owned and operated by the
agricultural giant Cargill,
which still operates about
10,000 acres of salt ponds
in the Bay.
The
project, estimated to take
30 years and up to $1 billion,
is the largest restoration
project in the West and
ranks third largest in the
nation, behind the restoration
projects of the Florida
Everglades and the Mississippi
River.
In Mountain View, the salt
ponds that Stevens Creek
empties into along Shoreline
Park have been undergoing
restoration, and 250 acres
of ponds that belong to
the U.S. Navy near Moffett
Field and another 55 acres
owned by the Midpeninsula
Regional Open Space District
could also be slated for
restoration in the near
future. The Moffett Field
ponds, called Site 25, were
used to collect storm water,
not to produce salt, although
they are next to salt ponds
and provide habitat for
birds.
Teeming wetlands
Each year
millions of birds come through
the Bay Area, a major stop
on the Pacific Flyway. Other
animals call the South Bay
home year round, such as
hawks, great blue herons,
snowy egrets and even the
endangered salt marsh harvest
mouse. Steelhead and Chinook
salmon also live in the
Bay.
Around the mouth of Stevens
Creek at Shoreline Preserve,
tidal marshland has returned
to some former salt ponds.
At one time the area was
a wilderness of water and
grasses; with tidal wetlands
stretching as far as the
eye could see. Before it
was channelized in the early
1900s, Stevens Creek would
have meandered through willow
groves near Rengstorff Avenue
before sweeping through
tidal grasslands into the
Bay.
Today, Shoreline's pathways,
built on top of levees,
skirt the salt ponds, some
of which have been restored.
Gates allow tides to flow
through the levees, which
form the ponds. Some gates
have been opened, thus flushing
the ponds and bringing salt
levels back to normal. With
the return of the natural
tidal cycle have also come
the grasses and shrubs endemic
to the area.
Since many birds that have
lost habitat in the Central
Valley now rely on the algae,
microbes and brine shrimp
that thrive in the salt
ponds, some of the ponds
will remain as they are
as part of the project.
Challenges
ahead
The return of Bay waters
to the ponds has raised
concern among some environmentalists
and scientists. Constructed
in the 1850s and '60s, the
salt ponds were saved from
being contaminated by mercury,
which leached down from
the Sierra Mountains during
the Gold Rush.
"We don't really know
what's going to happen," said Briggs Nisbet, restoration campaigns manager for
Save the Bay, one of the organizations spearheading the project. "We
know that when the Bay water
returns to the salt ponds
it will probably carry mercury
with it."
It will take more than 100
years for all the mercury
to flow out of the Bay into
the Pacific Ocean through
the Golden Gate, she added.
Cleaning up Moffett
For nearly six years Save
the Bay has been campaigning
to clean up the Moffett
ponds, which are part of
the Stevens Creek estuary.
Looking out at Site 25 from
one of Shoreline's paths,
Nisbet commented that the
South Bay restoration is
unlike any other projects
of this scope.
"What's different about this is that it's not out there. It's in
an urban area right here," she
said.
It is estimated that the
Site 25 restoration could
cost $2 million to $10 million
and take about a year to
remove contaminated sediments,
which would need to be trucked
offsite. Thus far, the Navy
has spent approximately
$90 million on Moffett Field
cleanup.
http://latc.com/2005/03/16/special_sect/special_sect4.html
Copyright © Los Altos
Town Crier