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Testing The Waters
Most great cities owe their prominence, at least in part, to a body of water.
Some have rivers running through them that make them a stop for trade and, with
enough bridges, a good place to cross. Others, like Houston, have a port on a
major body of water that brings cargo and commerce to their shores.
One of the challenges for such cities - Houston included - is ensuring the
health of these water bodies by limiting the amount of pollutants to which
they are
exposed.
Professor Hanadi Rifai contributes to these efforts in Houston and beyond
by creating sophisticated models of watersheds that help determine how much
pollution
a body of water is taking in and where that pollution is coming from. The pollution
levels Rifai finds are then compared to what is deemed acceptable under the
Clean Water Act and the Environmental Protection Agency’s Total Maximum
Daily Load (TMDL) Program.
Building these models, Rifai said, is a hugely complex task. Typically, she
and her research team start by combining multiple databases that quantify a
watershed’s
land use and land coverage, industrial and agricultural activity and potential
pollutants that may arise from those activities, population distribution and
density, soil types and topography.
Each of these, she said, are fed into a computer to form a single watershed
model. Data collected out in the field, such as information gathered through
water and
sediment tests, soil tests, (since what is on the ground usually gets washed
into a watershed), and air quality tests (since what is in the air can precipitate
into bodies of water and onto the ground), is also used to validate and refine
the team’s computer models.
The challenges of gathering information, quantifying it and making it part
of a large model differ from area to area, Rifai said. Modeling a watershed
in an
urban area such as Houston requires tracking more industrial pollutants and
understanding how having large areas covered by concrete impacts a watershed.
Models of rural
areas must account for agricultural pollutants such as pesticides, as well
as the impact of any livestock that live in the watershed.
These models and the real-world tests supporting them are then used to determine
how much pollution a body of water is exposed to in light of the total amount
of pollution that is considered acceptable. This sets the stage for the EPA
and other interested parties to solve any pollution problems a body of water
might
have.
“
When we come up with these system-wide models, they’re used for decision
making,” Rifai said. “The EPA will sit down with officials and
stake holders in these water bodies and figure out who is responsible for reducing
pollutants.
Determining exactly what actions should be taken to reduce pollutants is
a separate field of science from Rifai’s watershed modeling, and the
strategies and plans change depending on the problems. If sediment is an issue,
for example,
retaining ponds that allow sediment to settle before it reaches a major body
of water can be constructed. If a body of water has too much industrial waste,
the businesses responsible for that waste can be mandated to reduce their pollution
levels.
Another area of application for this research lies in the newly formed SSPEED
Center, of which Rifai is co-director. The center - whose acronym stands for
Severe Storm Prediction, Education, Evacuation from Disasters - is made up
of researchers from multiple universities in Texas and Louisiana, including
UH,
Rice University, Texas A&M University, Texas Southern University, Louisiana
State University and others.
Each of these universities, said Rifai, houses expertise in an area directly
related to severe storms, disaster preparedness and evacuations. UH researchers,
for instance, posses expertise in water quality and sensing; at Rice, in flooding;
at TSU, in transportation and traffic flow.
By combining all this talent under the SSPEED umbrella, individual researchers
can work together to conduct research projects that take comprehensive approaches
to severe storms and flooding (such as connecting localized flooding and rainfall
models with the National Hurricane Center’s hurricane projections), evacuations
and other issues.
“
From the SSPEED perspective, my interest is in looking at our watershed. I’m
working on water quality, others are working on flooding. We should be in contact
because those things are obviously connected,” she said.
In addition to providing a forum for collaboration, Rifai said SSPEED is designed
to offer students at the member institutions an interdisciplinary understanding
of what a severe storm or disaster entails from the standpoint of preparation
and recovery. The information students will be exposed to may include everything
from flooding models, storm tracking and path projections, to fields that deal
more heavily with the social sciences, such as what motivates individuals to
evacuate.
“
As an engineering student, you might be motivated to learn about atmospheric
science or other phenomena that you wouldn’t encounter in a traditional
engineering curriculum,” Rifai said. “I see the influence of the
center growing over time as we reach out to other disciplines and cross-pollinate
with different programs.”
Reprinted with permission of the University of Houston Cullen College of
Engineering.
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