Smith's team studies impact
Researchers hope to determine
how - and to what degree—development impacts the natural
opossum floats by belly-up. A ripe stench rises from leaking
sewage pipes beneath the murky water. A demandingly large
sign warns passersby “Do NOT touch the water.”
Glamorous it may not be, but to James
Smith, professor of civil and environmental engineering,
this is an exciting place to be. He is certain that anyone
stepping foot on this site for the first time would “have
to say ‘Wow.’”
Professor Smith and his research team
are studying urban watersheds such as this one in Baltimore,
Md., trying to understand the hydrology and hydraulics of
extreme floods in urban environments.
The project is part of the Baltimore Ecosystem
Study, and the National Science Foundation’s (NSF)
Long-Term Ecological Research initiative. NSF chose Baltimore
as one of two centers (the other being in Phoenix) for a
10-year study on urban environments.
Scientists, policy-makers, environmentalists,
and city residents all have many questions about how urbanization
impacts the natural environment. Some theories aver that
urban development disrupts the
water cycle, lowering water tables,
and essentially “drying out” the environment. Some
speculate that development disrupts the drainage basins of
rivers and streams, damaging watersheds and increasing the
severity of floods.
In search of data
Photo by James Smith
Graduate student Kate Meierdiercks,
left, and Hidde Leijnsel, a former student of
Professor James Smith, run experiments in a watershed
outside Baltimore, Md.
The major purpose of this research is
to gather more empirical data that will lead to enlightenment
on some of these questions.
Professor Smith’s team of hydrologists
mainly studies the river mechanics. Research staff member
Peter Nelson ’03 made an intriguing discovery while
poring over old topographic maps of the Dead Run Watershed
just outside Baltimore.
“The channel meanders around and
has a very particular form to it. Peter showed that Dead
Run has been remarkably stable over a time scale of about
100 years, when most of the development in the area took
place,” Professor Smith said. “That was kind
of surprising, because it’s at odds with the standard
model of how rivers work in urbanizing watersheds. We would
have expected the river to change its form much more, and
have more erratic behavior over time.”
To make his point, Mr. Nelson gathered
very high-resolution data about the present topography of
the area using LIDAR, an instrument capable of supplying
a fine-tuned one-meter resolution. He compared those data
to that from the old maps, as well as data from hydraulic
models, and came up with an idea as to why Dead Run had passed
through the last century so unchanged.
by Frank Wojciechowski
Professor James Smith and his
research team are trying to understand the hydrology
and hydraulics of extreme floods in urban environments.
“Right now, the working hypothesis
is that this particular stream is bedrock-controlled,” Mr.
Nelson said. This solid-rock surface protects the stream
channel from the drastic alterations that floods cause in
most streams. Thus, Mr. Nelson found that the geology of
the region can create an “imposed stability” in
the stream channel—an important piece of the puzzle
when trying to make sense of the watershed.
Another researcher, graduate student Kate
Meierdiercks, is researching the human side of the issue,
studying the different management practices that rule over
“A lot of the research I’ve
done has been uncovering the history of storm water management,” Ms.
Meierdiercks said. She explained that prior to the Clean
Water Act and other policies that pushed for more environmental
management, there really was no storm water management to
In the 80s, the preferred management practice
was the creation of dammed detention basins that hold extra
water. Later development practices preferred storm water
"All of these areas developed at
different times, so they have different methods that affect
flooding in very different ways."
Ms. Meierdiercks is studying the region
as a whole, piecing together the various local water management
systems, and trying to describe how they collectively impact
the flood activity of the region.
However, some areas are characterized
less by their management and more by their lack thereof.
The older areas of the city are defined by the lack of hydrological
sophistication available at the time of their development.
The unappealing site described earlier
is an area in northeast Baltimore called Moores Run, that
were developed in the early 20th century. At that time, part
of the meandering stream was paved over. Beneath it were
placed large sewer mains that carried a very high volume
and were installed at a very high gradient in order to move
a great deal of water very quickly.
This high-velocity flux was too much for
the small stream and entirely destroyed the structure of
the stream channel, leaving leaky sewage pipes exposed and
creating a serious public health hazard.
“Moores Run is really a model of
the old development worst-case scenario,” Professor
Smith said. “Moores Run also has the highest frequency
of flood peaks exceeding 100 cfs per square mile in the conterminous
In plain English, Professor Smith explained
that a “flood peak” is the highest level attained
by the floodwaters. The benchmark figure used by the United
States Geological Survey to identify severe floods is 100
cubic feet per second (cfs) per square mile.
Although regions of Hawaii and Puerto
Rico tend to have much higher flood peaks, there is nowhere
in the United States that has more floods that reach peaks
above that level.
Simply said: a lot of bad floods happen
in Moores Run, which is one of the reasons it was chosen
for the study.
The research team experienced some of
Baltimore’s flooding behavior firsthand while conducting
fieldwork over the summer. After several tedious hours of
gathering unexciting data in a steady drizzle, the team decided
to take a lunch break. But before they finished their meal,
research associate Mary Lynn Baeck called from her desk in
Princeton, where she was watching real-time weather data
of their area. She hustled them out of the restaurant with
promises that some serious rain was minutes away.
“We got about 15 or 20 minutes
of heavy rain that made the trip worthwhile,” Professor
Smith said. “We collected a lot of very useful data.”
Traipsing around a flood zone during a
storm is not a terribly safe activity, so they kept in touch
with Ms. Baeck and each other through cell phones, by working
in teams, and following the mantra: if you feel you’re
in danger, you probably are, so get out.
In November, three Baltimore residents
died in a severe flood, further impressing upon the researchers
the importance of their work.
Graduate student Julie Javier is
focusing upon possible applications of the research and is
attempting to enhance flood forecasting practices and safety
Despite the danger and the messiness of
the work, the team takes it all on with brio.
“I’m inspired by the belief
that the urban environment is one of the biggest challenges
of the 21st century,” Professor Smith said. “Figuring
out how to keep the urban environment livable is a tremendous
“Also, I was a graduate student
at Johns Hopkins University [in Baltimore], and one of my
favorite teachers was a fellow named M. Gordon Wolman,” he
said. “He took the approach that the urban environment
had some of the most exciting scientific challenges.
“I bought into this idea.
If you think about it from an experimental perspective,
the types of experiments you carry out in natural systems
in urban environments are absolutely staggering.”
Mr. Nelson was encouraged by the curiosity
of local children.
“When we were working out in the
streams, elementary and middle-school-aged kids came up and
were really curious about what we were doing,” Mr.
Nelson said. “Making science more accessible to young
people in urban environments is something that can only be
Ms. Meierdiercks agreed with her research
teammates and added that the possible impacts of the research
itself were especially invigorating.
“We can answer questions that are
going to help a lot of people,” she said. “If
we can figure out some way to prevent the destructive flooding
in Baltimore, we’ll be helping hundreds of thousands
“Also, people have messed up the
hydrology of the natural drainage systems so much that it
just seems natural that we should have to go in and try to
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