have always been
magnets for college
students. But when University of North Texas students and professors from
the Institute of Applied Sciences head to Lake Lewisville, they have something
other than swimming in mind. Working on projects developed by the IAS,
they are examining critical natural and human resource issues facing Texas,
the nation and the world. Among the most pressing of these issues are
water quality and quantity.
Tom LaPoint, professor of biological sciences and director
of the IAS, gets right to the point. Within 15 to 20 years, he predicts,
water use in the region will have caught up with water supply.
"That means it will start controlling economic
growth, and that is getting people's attention," he says. "Water
has to be managed well because it's going to affect economic growth and
economic well-being in North Texas."
Area lakes like Lake Lewisville, he says, are the objects
of competing interests. They serve as water supply, recreation area and
wildlife environment. Each use must be taken into account in the development
of a water management plan.
where projects like LaPoint's Stream Team come in. This and other IAS
programs are providing relevant data to local governments so that people
can make informed choices when dealing with water quality problems.
The Stream Team, headed by LaPoint, is made up of a
group of UNT students and other faculty members, along with city of Denton
employees. Their project, the Stream Research Facility, assesses the condition
of the water flowing into Lake Lewisville
a major source
of drinking water for Denton and Dallas counties.
at the municipal sewage treatment plant on Pecan Creek, the facility is
made up of 12 artificial streams that mimic the natural streams of the
region. Each stream is 16 feet long and two feet wide, with a gravel bed
similar to that found in natural streams. The streams are stocked with
aquatic creatures such as insects, larvae, snails and fish.
Researchers are able to examine the effects of chemicals
that are commonly found in the lake, such as the gasoline additive MTBE
(methyl tertiary butyl ether) and herbicides and pesticides such as atrazine
and diazinon. By noting how the chemicals react with one another and with
the aquatic life, the Stream Team can determine which chemicals are of
concern and gauge the effectiveness of the city's water treatment system.
IAS projects like these are successful, LaPoint says,
because they involve aquatic biologists as well as chemists, geographers,
GIS (geographical information systems) landscape analysts, sociologists
and even members of UNT's environmental philosophy and environmental journalism
programs. This interdisciplinary approach provides a "big-picture"
assessment to the public officials who establish and implement policies
related to water use.
are some of the issues facing the North Texas area? Pesticides, herbicides
and compounds like MTBE are obvious, says LaPoint. But another issue that
many people don't think about is sediments.
"That's a big problem in reservoirs in the West
and in Texas," LaPoint explains. "Suspended sediments
water from construction sites or are washed off roads or agricultural
sites. When sediments move into a lake like Ray Roberts or even Lake Lewisville,
they start to fill it up. The basin isn't as deep as it used to be, and
the capacity for water storage decreases. It's become a serious problem
at Lake Texoma (on the Texas/Oklahoma border)." To help decrease the incoming
sediments, standard soil conservation measures are being applied to agricultural
lands near the lake.
issue worthy of public attention, says LaPoint, is the connection between
surface water and groundwater.
"Where groundwater aquifers are depleted, the
surface water tends to disappear because water is moving to refill the
aquifer. So you can have disappearing streams. Water that should be moving
downstream moves down into the aquifer to try to replenish that."
The influx of people into Denton and Collin counties
poses a twofold problem, says LaPoint. "We're increasing the need
for available water, and we're paving over ground that absorbs water.
Research shows that the incidence of flash flooding is directly proportional
to the degree of building in a watershed. We're taking away permeable
surfaces with all this growth, so water can't percolate down to replenish
increase in public awareness of the issues surrounding water supply and
use is a hopeful sign.
"People are beginning to think about this," says
LaPoint. "We've always been able to open a tap and draw water. Now
we have to learn how to manage water, and that includes managing wastewater."
Clearly, research universities such as UNT can play
an important role in managing water quality and quantity. "The interesting
thing for us is that we're not just looking at the toxicity and hazards
of MTBE and other chemicals," LaPoint says. "We're working in a broader
sense with economists, managers, public officials and others about how
to manage the overall problem. And that, I think, is a good focus for
is uninvited guest at Party Cove
MTBE or Not to MTBE: That Is the Question!" Such was the light-hearted
title of a Spring 2000 environmental science seminar conducted by
Ken Dickson and graduate student Anne Lee. But to Dickson, Regents
Professor of biological sciences and former director of the Institute
of Applied Sciences at UNT, the MTBE issue is a serious one.
Methyl tertiary butyl ether, or MTBE
for short, is a gasoline additive that acts as an oxidant. It makes
gasoline more volatile, enhancing combustion and thereby cutting
down on emissions into the atmosphere.
But what's good for the air is not
necessarily good for the water. For more than two years, Dickson,
Lee and other graduate students have been looking at the levels
of MTBE in Lake Lewisville - especially at a spot known as Party
Cove, close to the intake for the city of Denton municipal water
supply. Gasoline leaking from boats tied up at the popular spot
and from two-stroke engines in recreational vehicles such as jet
skis increased MTBE to such levels that city officials have placed
a boom across the cove to block boats from entering.
The additive poses an even greater
problem in groundwater than it does in surface water. When it is
present in surface water, the compound reacts with oxygen and evaporates
into the atmosphere. If the supply can be cut off, the water will
eventually clean itself up. But because MTBE cannot react with oxygen
and evaporate when it is underground, it remains in groundwater.
Leaks in gasoline delivery pipelines and underground storage tanks
are the biggest culprits in groundwater contamination.
Although current concentrations of
MTBE are not considered to be a threat, officials at all levels
of government are closely watching the build-up of the potential
"There are a lot of unknowns about
MTBE," Lee says. "We hope this project may lead to wiser ecological
and economical management of recreational activity on lakes."
speak eloquently about water quality
When Tom Waller's clams clam up, people listen. Waller, professor
of biological sciences and director of the Aquatic Toxicology
Laboratory at UNT's Institute of Applied Sciences, and doctoral
student Joel Allen are using the Asiatic clam as a sentinel
in the Texas Elm Fork watershed, which includes Lake Lewisville,
Lake Ray Roberts and Grapevine Lake.
Testing water for the presence of individual
chemicals, says Waller, does not necessarily give an accurate
or complete picture of its quality. "Living material is the
best measure of toxicity because it integrates the totality
of its environment," he says.
When clams sense that the water in which
they live is toxic, they protect themselves by closing their
shells. The distance that a clam's shell is open, known as gape,
can tell Waller and his fellow researchers when the water in
the Elm Fork tributary, which flows into Lake Lewisville, is
contaminated. Changes in gape, picked up by small sensors to
which the clams are attached, are transmitted via cellular modems
to a lab on the UNT campus. There the information is processed
and posted on the project web site, www.ecoplex.unt.edu.
The clams are part of a much larger monitoring
program that involves geographical information systems, satellite
imagery, hydrology, land use and other methods, says Waller.
"Access to the data is one part of understanding
what is going on in a watershed," he says. "Interpreting the
data is another part. Through education, we hope to help the
public interpret the data." To that end, teachers in the Denton
Independent School District are developing curricula designed
to teach K-8 students about watersheds.
"Anything that goes on in the watershed has
a potential impact on the reservoirs and hence our drinking-water
supply," Waller explains. "Ultimately we hope to monitor the
entire watershed in a way that will help us understand potential
trouble spots and manage them to maximize the benefits to the
animal and plant populations as well as the humans."
The study, a joint effort by UNT and the
city of Denton, is funded by the Environmental Protection Agency's
EMPACT (Environmental Monitoring for Public Access and Tracking)
and graduate student Joel Allen paddle out to the Water Quality
Monitoring Platform at Lake Lewisville (top) to check the
clam housing (middle). By the distance that their shells are
open, the clams (bottom) can tell the researchers when the
water in the Elm Fork tributary is contaminated.