waters' precipitous flow
It’s an obvious, but often-quoted engineering axiom: Water runs downhill.
Sometimes it runs a little too fast, especially on the steep slopes of North Carolina’s westernmost counties.
Cooperative Extension staffers of the French Broad Training Center at the North Carolina Arboretum near Asheville are busy helping landowners and others establish a variety of best management practices (BMPs) to slow rushing storm-generated freshets and improve mountain water quality by filtering pollutants and slowing soil erosion.
“We try to balance sound management practices with economic growth,” says
Jon Calabria, center coordinator and Cooperative Extension faculty
member in the College’s Biological
and Agricultural Engineering (BAE) Department. “These BMPs are tools for informed development
in ways that help protect and enhance the environment and mitigate
development impacts. The economic component is to balance, not exclude
development.”
Calabria, a landscape architect; Eric Caldwell, Cooperative Extension director for Transylvania County; and Cliff Ruth, a cross-county Cooperative Extension agricultural agent, are constantly in the field, preaching and demonstrating the water quality gospel. They’re assisted by Dr. Greg Jennings, BAE professor, Extension specialist and associate director of the Water Resources Research Institute.
In this case, the field is along the French Broad River and its upper tributaries in Transylvania, Henderson, Buncombe and Madison counties.
“With the continuing and anticipated population growth for western North Carolina, it’s now more important than ever to take measures to guide future growth and development to ensure long-term protection of water resources and quality of life,” says Calabria, who’s the training center’s coordinator.
“Our workshops and demonstrations raise awareness of urbanization impacts on water resources and present key planning concepts at the watershed and site level,” he said. “They also providing options for communities to meet water quality regulations we believe will lead to better land-use decision-making by community leaders.”
And the specialists practice what they preach.
Last summer, Extension staffers, state Department of Corrections workers, N.C. Arboretum staff and volunteers spent two weeks installing a demonstration stormwater wetland at the arboretum’s Plant Professional Landscape Garden, also used as a test site for commercial nursery workers’ professional training and certification.
“A stormwater wetland was the most cost-effective option, providing the maximum water quality benefit,” Calabria says, “and since the project is highly visible, we tried to construct an aesthetically pleasing garden entrance that also demonstrates indigenous plant uses.”
Calabria and crew planted 12 indigenous plant species at different levels, according to the plants’ ability to remain saturated for long periods. For example, they placed Juncus effusus (Soft rush) and Iris virginica (Blue iris) at the lowest elevation, and Sporobolus heterolepis (Prairie dropseed) — an upland species — around the rim at the highest elevation where it would be infrequently immersed in water.
“Restoring naturally occurring plant communities, composed of indigenous species, in these areas will have the most ecological benefit,” Calabria says.
As if to test their theories, a few hours after the crew completed the project, a steady rain broke a lengthy drought and, says Calabria, “The wetland did what it was supposed to do.”
What it was supposed to do was improve water
quality by slowing stormwater and allowing
its treatment
by plants and soils,
removing or reducing
pollutants such as sediment, phosphorous,
nitrogen, heavy metals and bacteria from an arboretum
roof, parking lot
and lawn.
The wetland also reduced peak water discharge.
That lessened downstream
erosion
along Bent Creek, which flows through the
arboretum.
— Art
Latham
