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Engineering a Cleaner World
Environmental and Water Resources Research
by Marlys
Amundson
Faculty and students involved in UCLA's environmental engineering
and water resources programs strive to understand how best to achieve
and sustain a healthy environment in the face of ever-increasing
population pressure. They pride themselves on blending real-world
field investigations with fundamental theory in examining the physical,
chemical and biological processes governing the transport and fate
of contaminants in air, land and water. They apply the same methods
to modeling groundwater, large-scale water resources systems, and
land-atmosphere interaction.
Professor William Yeh, who is also chair of the Civil and Environmental
Engineering Department, has developed highly-involved computer models
for optimal management and operations of large-scale hydropower
and water supply systems, such as the California Central Valley
Project and the Metropolitan Water District of Southern California,
which provides water to more than 17 million people in Southern
California.
Additionally, Yeh has been involved in the development of methodologies
for conjunctive use planning of surface water and groundwater for
sustainable management of water resources in semi-arid regions.
Through his research, Yeh has developed storage and retrieval models
that ensure water quality in an aquifer remains high. For a recent
project at the San Pedro river basin in Arizona, Yeh examined ways
of optimizing groundwater supplies without adversely affecting the
ecosystem.
"Our challenge was to balance increasing population demands
and the needs of endangered species in the area," Yeh notes.
"To ensure the sustainability of the water reserves, we needed
to find a way to satisfy these competing objectives."
Professor Michael Stenstrom is pioneering research in urban storm
water runoff. Through an exhaustive wet- and dry-weather monitoring
program, his research group has developed a geographical information
system linking land use to runoff contamination and, more importantly,
has begun to pinpoint the root of some of Santa Monica Bay's
worst pollution
problems.
The emphasis of their current work is on cataloguing pollutant levels
in the first flush runoff. They have three test sites located along
the 405 Freeway, where they take samples from the runoff each time
it rains - five times in the first hour, then once each hour as
the rain continues.
"We are testing the runoff samples collected at each site for
levels of heavy metals, organic compounds, and other traditional
pollutants," says Stenstrom. "It won't be possible
to treat everything, but once the models are complete, we will be
able to determine the most effective way to reduce the effects of
storm water pollution."
Once they know the magnitude of the pollutants in the early hours
of a rainstorm, his group will be able to determine the effectiveness
of a system that treats the first hour of freeway runoff, hopefully
eliminating as much as 50 percent of the pollutants. They also are
using the data to model first flush runoff and build-up on the freeway
from tailpipe emissions, brake pad shavings, and other drippings.
Professor Keith Stolzenbach and his research group have shed new
light on the processes by which urban particulate matter is transported
by the atmosphere and deposited into the coastal environment. Using
measurements collected at seven sites, he is creating sophisticated
computer models of the atmosphere to better understand deposition
patterns. This work has identified previously unknown links between
coastal water pollution and Los Angeles area air quality. In addition,
his research team is conducting coastal water quality studies, an
area he describes as environmental fluid mechanics.
"We have constructed complex models of water movement in the
Santa Monica Bay using measurements from various sites in the Bay
and data from satellites," Stolzenbach explains. "These
models show the impact of the eddy in the Bay and the movement of
fresh water into the Bay after a rainfall."
His research provides valuable data to fisheries for tracking nutrient
information and spawning locations, and for water quality studies
looking at how sediments settling into the Bay impact the ecosystem
and health issues in the surf zone.
Stolzenbach works closely with colleagues in atmospheric sciences,
public health, and chemical engineering through UCLA's Institute
for the Environment, where he is the Coastal Center Director.
Professor Thomas Harmon's group continues to examine problems
of local and national importance while advancing the state-of-the-art
embedded networked sensing of contaminants in soil and groundwater.
In one project, the group is examining natural sources of hexavalent
chromium (prominent in the film "Erin Brockovich") in
Mojave Desert groundwater. In another, his team is screening native
California plants to identify species suitable for phytoremediation,
the process of cleaning contaminated soils with plants.
Underground storage reservoirs, while preventing loss through evaporation,
present other challenges. Water coming to the reservoir from snow
melt or rain travels through the soil, picking up natural contaminants
(such as arsenic and chromium) leached from the rocks. Harmon's
group is using numerical computer models to simulate the flow within
the aquifer and determine the optimal methods to minimize contamination.
Working with public health professor Rich Ambrose, Harmon is exploring
habitat restoration using native Southern California plants to clean
contaminated soils. They initially tested 20 species in pots for
their durability and effectiveness, four of which they are using
in the larger eco-remediation study.
"We have planted two types of shrubs and two types of native
grasses in troughs on campus that were filled with contaminated
soil from local oil fields," Harmon explains. "We are
testing several approaches to determine the most effective passive,
low-cost approach to restoring contaminated property to native conditions.
There are a limited number of open, natural spaces in the Los Angeles
area, and this is one solution to cleaning up rail yards and other
polluted areas."
Professor Steven Margulis is researching the interaction between
the land surface and atmospheric boundary layer, as well as the
development and use of remote sensing observations, and the optimal
combination of these observations with hydrologic models.
"We're working to characterize important hydrologic fluxes
over large scales and better understand the underlying mechanisms
responsible for their variability over time and space," says
Margulis. "Major fluxes in the hydrologic cycle like evaporation
and recharge are essentially unmonitored on continental or global
scales. By obtaining better estimates and predictions of these fluxes
we will ultimately be able to improve management of water resources
and mitigate the effects of environmental hazards such as floods
and droughts."
In his work, Margulis is using traditional measurements as well
as remote sensing from satellites for measurements of clouds, rain,
and other forms of water in the earth system to develop accurate
models of fluxes of water and energy in the hydrologic cycle.
This summer, Margulis will be participating in a large-scale field
experiment in the Midwest where many scientists will be undertaking
simultaneous field sampling and remote sensing observations from
airborne sensors. The goal is to gather additional data for testing
hydrologic models and to gain a better understanding of the important
physical processes involved.
Professor Jenny Jay's research interests include the ecology
of pathogenic
organisms in the coastal environment, and the fate of arsenic and
pathogens in water treatment systems.
Her team is among the first to examine the distribution and survival
of fecal indicator bacteria and pathogens in Santa Monica Bay sediments.
"There are significant gaps in our knowledge of the factors
affecting environmental pathogen survival, transport, and ecological
relationships. The role of sediments in pathogen survival and the
persistence of these organisms in dry sand are two topics that are
particularly understudied," explains Jay. "We will be
testing areas in the Santa Monica Bay to locate the hot spots and
compare the accumulation of sediment pathogens in enclosed beaches
to beaches with high circulation patterns. Sediments may provide
high levels of nutrients for the pathogens, as well as protection
from UV rays, making them prime areas for accumulation of these
organisms."
Her team will use quantitative molecular tools to measure the bacteria
levels and to study the ecology in the sediment. They will coordinate
field studies with microcosm studies under controlled conditions
in the lab. The data they gather could be used to determine if dredging
is necessary to reduce contaminant levels in enclosed beaches, and
to determine the area impacted by run-off from a storm drain.
Over summer, Jay will explore methods of optimizing the effectiveness
of seawater as a coagulant for removal of specific pathogens in
wastewater treatment systems.
For additional information on research in the Civil and Environmental
Engineering Department, please visit http://www.cee.ucla.edu/.
Photo: Todd
Cheney, UCLA Photography |
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