Three Runs Creek Fact Sheet
Upper Three Runs Creek is a 20-mile (40-kilometer) waterway that meanders
through hardwood and cypress forests on the 310-square- mile (806-square-kilometer)
Savannah River Site near Aiken, S.C. It empties
into the Savannah River. The creek is a blackwater stream because of its
high concentration of naturally occurring tannic acid that gives the water
its tea color. Scientists have recorded more than 575 species of aquatic
insects in Upper Three Runs, probably giving it the second highest level
of aquatic insect biodiversity in the world. Breitenback Creek in southern
Germany contains a recorded 635 aquatic insect species. The next highest
levels of aquatic insect biodiversity are found in tropical streams in
Malaysia and Australia, but both have fewer than 400 species.
Though scientists have documented more than 575 species of aquatic insects
in Upper Three Runs Creek, the figure does not include other species of
invertebrates. These include round worms, crayfish, other large crustaceans
and mussels. Altogether, the stream may contain as many as 700 invertebrate
Upper Three Runs is the only known locality of the blackbanded sunfish
and the turquoise darter in the Savannah River drainage.
The bottomland area and adjacent valley slopes surrounding Upper Three
Runs Creek are important habitats for plants. Eight plant species that
are listed on federal and/or state lists of species of special status
are found in this set-aside area. They are: sandhill seedbox, milk pea,
bog spice bush, Nestronia, green- fringed orchid, Oconee azalea, spatulate
seedbox and Chapman's sedge.
Scientists at Savannah River Ecology Laboratory believe Upper Three Runs
Creek has such a high level of biodiversity because of a suite of unique
characteristics working in concert. For one, Upper Three Runs is a spring-fed
stream, which results in colder water temperatures. Thus, typically northern
and mountain species of aquatic fauna coexist with the native southeastern
Researchers are using molecular biology techniques such as fatty acid
analysis, physiological determinations, reverse genome probing and RNA
sequencing, to learn more about the microbial communities that inhabit
Upper Three Runs Creek. Microbes control most ecosystem level processes,
such as nutrient and mineral cycling, which are necessary for the growth
of other organisms. If scientists can determine that a habitat contains
a healthy and diverse community of microbes, they can say it is a healthy
environment. If there are only a few microbes present, an ecosystem's
functions are limited. Waste products are not broken down; they accumulate
in the environment.
Blackwater streams, such as Upper Three Runs Creek, are found throughout
the southeastern United States. Many, however, suffer from pollution and
siltation, which Upper Three Runs has only experienced at a minimum because
of its location within the controlled access area of the U.S. Department
of Energy's Savannah River Site. The stream also flows through a DOE- protected
research set-aside area that cannot be developed for industry or forestry.
Did You Know?
- Since the SRS was established in 1951, the overall
management policy has called for the stream to be a "control,"
receiving as little impact as possible from site operations. No effluents
are discharged into the upper region of Upper Three Runs Creek. Also,
all routine forest management has ceased on the floodplain and adjacent
- Upper Three Runs is home to a number of invertebrate
species found nowhere else in the world and many that are rare. One
species found only in Upper Three Runs is a caddisfly called Cheumatopsyche
richardsoni. Three other caddisflies of the same genus also live in
the stream. Thus C. richardsoni was an ideal species to study the effect
of its unique native status on genetic diversity in the stream. As expected,
Savannah River Ecology Laboratory researchers found that the genetic
diversity of C. richardsoni was low, which limits its ability to disperse
to other locations. Also, researchers recently identified a new family
of isopods from that inhabits an aquatic zone beneath Upper Three Runs.
The isopod family's nearest living relatives are found in eastern Europe
in a similar habitat.
- The Upper Three Runs/Tinker Creek Research Set-Aside
at SRS has been the focus of many ecological studies conducted by scientists
at the Savannah River Ecology Laboratory and their colleagues from other
institutions. Studies include research on wood ducks, red-cockaded woodpeckers,
small mammals, aquatic insects, fish communities, rare and threatened
plants, forest dynamics, biological and chemical cycling of elements
in streams and seasonal fluctuations of acids in soils.
- Studies of Upper Three Runs Creek are giving
scientists an example of a relatively protected stream that can be used
as a bench mark for environmental mitigation and restoration of polluted