NASA Helps Reclaim 15,100 Acres of San Francisco Bay Salt Ponds

NASA technology is helping state and federal governments reclaim
15,100 acres of salt evaporation ponds in South San Francisco Bay,
during one of the nation’s largest restoration projects.

A small group of NASA scientists and technicians is studying salt
evaporation ponds by using sensors on satellites and airplanes in
addition to surface sampling, to learn how restoring the ponds to
nearly their natural state may affect local ecology. The U.S. Fish
and Wildlife Service and the California Department of Fish and Game
recently bought many salt ponds from the Cargill Salt Company for
$100 million. Scientists think the project will continue for more
than 20 years.

“It is the largest tidal wetland restoration project in the western
United States,” said Marge Kolar of the U.S. Fish and Wildlife
Service, Fremont, Calif.

“We are using sensors on satellites and aircraft, together with
on-site sampling, to evaluate water quality of coastal wetland
environments in the southern San Francisco Bay,” said L. Jean
Palmer-Moloney, a visiting geography professor from the State
University of New York, Oneonta, who is leading the monitoring effort
at NASA Ames Research Center, located in California’s Silicon Valley.
Her team includes Jim Brass, Dana Rogoff and Brad Dalton, all of NASA
Ames.

For more than a century, people used the salt ponds and the abundant
California sunshine to evaporate water and collect salt. This process
changed the natural habitat of local plants and animals. The U.S.
government, the state of California and other organizations now are
working to restore the salt ponds to as close to the original,
natural habitat as is practical. Work includes reducing salinity,
reconnecting many of the ponds to the bay and looking for changes in
the local environment.

“We are in a position to help determine the current state of the
ponds,” Palmer-Moloney said. “As the transition from salt ponds to
tidal marsh habitat progresses over the years, we will be able to
monitor ecosystem changes with satellite- and aircraft-acquired data
to supplement field data collection,” Palmer-Moloney added.

“We are taking samples from the ponds to determine what microbes live
there as well as what the salt content is,” said Rogoff, a laboratory
technician working on the project. “We also will start using
satellite imaging to monitor the ponds’ microbial life,” she added.
Dirt levees separate the ponds from the bay. Before workers open
levees to return the ponds to the natural ecosystem, experts must
look at the effects of changing the salinity and habitat.

The California Regional Water Quality Board in Oakland is working
with the U.S. Fish and Wildlife Service and the California Department
of Fish and Game to determine ‘safe’ salinity discharge levels,
according to Palmer-Moloney.

“When trying to understand the current state of the ecosystem in the
south bay, the traditional method of getting information is from
point sampling,” said Palmer-Moloney. Collecting a water sample from
a pond is one example of point sampling, she added. “In the field, a
sample might show water pH, water temperature, salinity. In the lab,
this same sample would provide information on the microbes that live
in the water,” Palmer-Moloney
explained.

“If you fly a plane over the salt ponds along the bay, you’ll see
they are different colors,” Rogoff said. “These colors are often due
to the microbes that live there, and we need to monitor them to make
sure that we keep everything in balance as the team opens more of the
ponds to the bay,” Rogoff added.

Remote sensing from satellites and aircraft allows scientists to
quickly deduce surface conditions over a wide area, the equal of
hundreds of hours of point-sampling on the ground, according to
Palmer-Moloney. Remote sensing is the use of sensors by satellites
and aircraft to take images of parts of the Earth’s surface in many
wavelengths, some beyond the reach of the human eye.

“We are interested in helping and facilitating decision making in the
restoration process, which is converting salt ponds to tidal marsh
habitat,” Palmer-Moloney said. “In a densely populated urban area
such as the San Francisco Bay area, green space and open space are
precious commodities, and right now, the urban build-up all the way
to the edge of the bay has been held in check for about a hundred
years by the industrial use of the coastal wetlands as salt ponds.”

Over the years, human activities have changed the ecosystem of the
southern San Francisco Bay. Some native plants and animals cannot
tolerate the higher salt content of the ponds. Yet other animals such
as the snowy plover bird thrive in the higher salt environments.
“What’s going to happen is that some of the ponds will be restored as
closely as possible to the original, natural condition of more than a
century ago,” Palmer-Moloney said. “However, the project will
maintain some of the salt ponds with higher salinity in order to
provide niches for animals and plants that prefer a higher salinity
habitat.”

Many salt evaporation ponds are located next to NASA property. “The
ecosystem doesn’t recognize boundaries that humans draw on maps,”
Palmer-Moloney said. “There are interconnections between NASA land
and the restoration area. There is an opportunity for NASA to
contribute to the bay restoration project. NASA has satellites and
aircraft with remote-sensing instruments already in place, and this
is a wonderful opportunity to use them.”

According to NASA scientists, the use of remote sensing to study
coastal wetland environments is fairly new, and the work now underway
to monitor the salt ponds in South San Francisco Bay may well serve
as a prototype for cooperative research by other state and federal
agencies.

“Hopefully, we can take some of what we’re learning in southern San
Francisco Bay and use it in other wetland areas in this country and
abroad,” said Palmer-Moloney. “In July, I’ll be going to Belize,
located just south of Mexico’s Yucatan Peninsula. In Belize, I’ll be
studying a place called Chetumal Bay to examine how to apply
technology we are using in the southern San Francisco Bay in Chetumal
to characterize and document change in tropical salt marsh
environments.” Palmer-Moloney plans to work with Belize’s Ministry of
Natural Resources’ Coastal Zone Management organization.

Some NASA scientific instruments scientists are using in the south
San Francisco Bay salt pond recovery effort include the Advanced
Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the
Terra satellite; the Moderate Resolution Imaging Spectroradiometer
(MODIS) instrument on the Terra and Aqua satellites; and the thematic
mapper on the Landsat 5 satellite. More information about the salt
ponds project is on the World Wide Web at:
http://geo.arc.nasa.gov/sge/wetlands

More information about NASA Earth sciences and how NASA researches
Earth and shares results with federal and state governments and other
organizations is on the Internet at: http://www.earth.nasa.gov/

Images of the salt pond project are on the web at:
http://amesnews.arc.nasa.gov/releases/2003/03images/saltpond/saltpond.html