NASA Ames Scientists Train the Next Generation of Earth Explorers
South of the San Francisco Bay is a 100-year tidal floodplain near NASA
Ames Research Center, Moffett Field, Calif. Because of the potential
for flooding, Ames purchased a segment of the mud flats for flood storm
management, and has used the area for field experiments to teach and
train gifted science students about the practical benefits of studying
the tidal salt marsh and its wildlife.
For the last eight years, NASA Ames Earth Science Division has been
participating in a student internship program called DEVELOP. Funding
comes through the Applied Sciences Program in the Earth Science
Division in the Science Mission Directorate at NASA Head Quarters. It
is a training and development program that provides an opportunity for
talented science students to learn and use sophisticated NASA
technology, while mentored by science advisors from NASA and partner
agencies. At the completion of the program, students share their
research results with local communities, demonstrating how NASA science
measurements and predictions can be used to address local policy
“Every summer is full of surprises. Our students usually work
on some aspect of the South Bay Salt Ponds Restoration Project,” said
Jay Skiles, a research scientist and program science mentor at NASA
Ames. “This year, one of our student teams studied the sedimentation
now taking place in the salt ponds after some of the levees were
purposely breached. The DEVELOP program is a great way for students to
learn science skills and meet professionals in the field.”
During the past two centuries, the San Francisco Bay has lost an
estimated 85 percent of its historic wetlands to fill or alteration.
This dramatic decline in the wetlands has caused a severe impact to
tidal marsh habitats and the fish and wildlife. In addition, the
changed environment has increased the risk of local floods, according
to South Bay Salt Ponds Restoration Project literature.
To help restore the wetlands, one of the first defenses was to
build levees that separate the ponds from the tides. It was expected
that once the levees breach, the sediment from the ponds would evolve
into tidal marsh. In addition, by phasing the restoration of tidal
marsh over many years, the need for large volumes of sediment also
would be reduced.
NASA scientists regularly mentor and teach students about the
scientific method, using inquiry and data collecting as a means of
assessment and resolution. At Ames, scientists have taken a proactive
role monitoring and studying fluvial (stream) and coastal flood
sources. In this case, they helped a team of students, ranging from
high school to university graduates, model the sediment deposits to
predict marsh habitat development.
“I heard about the internship program while I was attending
San Francisco State University,” said Michelle Newcomer, a master’s
student at SFSU and a DEVELOP team member. “I applied because it
sounded really exciting. I wanted to apply my geographic information
system (GIS) and remote sensing skills to a real-world project.”
The five-member team called themselves the Salt Pond Restoration
Sedimentation Team. They identified four project objectives: (1) track
sediment transport pathways to determine the source of sediment in the
South Bay; (2) calibrate satellite imagery with the collected suspended
sediment concentration measurements, using Landsat 5 imagery, and data
and imagery from NASA satellite instruments Moderate Resolution Imaging
Spectroradiometer (MODIS), and Advanced Spaceborne Thermal Emission and
Reflection Radiometer (ASTER); (3) create a GIS model to predict
sediment deposition and (4) assess the applicability of remote sensing
for predicting sediment deposition during restoration.
“We focused on two salt ponds in the Alviso complex, one of
which was referred to as Pond A21. Coyote Creek is the waterway that
connects the pond to the Bay. We also were interested in Pond A6
because it is the next pond to be breached; we wanted to use our model
to forecast marsh accumulation in A6,” said Newcomer.
To predict marsh accumulation, students used the marsh
sedimentation model, called MarSed, which was implemented in a
geographic information systems platform. The conceptual model has
different variables that effect marsh accumulation, including the
concentration of suspended sediments, how quickly sediment settles, and
time of flooding. Field work was necessary to get the suspended
Field work consisted of going out into the San Francisco Bay
on pontoon boats, provided by NASA’s Disaster Assistance and Rescue
Team (DART) facility. While on the boats, students collected water
samples at the bay’s surface, and recorded their exact location using a
Global Positioning System (GPS) device.
Once samples were collected, students began processing them at the U.S. Geological Survey laboratory in Menlo Park, Calif.
The team concluded that (1) the delta and Coyote Creek are primary
sources of suspended sediment to the Alviso ponds, (2) suspended
sediment concentrations could successfully be detected using remote
sensing, (3) sediment deposition for Pond A21 was successfully
predicted using remote sensing and GIS techniques, and (4) Pond A6 is
predicted to reach equilibrium conditions stable enough for vegetation
colonization after 60 months of tidal inundation.
The team reported that restoration managers can use these products as a
tool for determining the locations of pond breaches, as well as
understanding the time frame of future marsh development.
“We knew that we wanted our calibrated model to do well. At the end of
the project, we were all very happy, and felt accomplished that we had
actually got it to work,” said Newcomer.
For more information about the DEVELOP program, visit:
For more information about the South Bay Salt Pond Restoration Project, visit:
Ruth Dasso Marlaire
Ames Research Center, Moffett Field, Calif.