Building Sites Spill Silt into Streams

KNOXVILLE — A study of excavation sites in a four-county area of East Tennessee shows that state-mandated methods meant to keep dirt out of streams are not working, a UT researcher says.

Dr. Jack Ranney, an ecologist with UT’s Energy, Environment and Resources Center, found that streams in Knox, Sevier, Blount and Loudon counties are not effectively protected from soil that washes out of construction sites.

“The whole situation was appalling,” he said. “I found improper installation and poor maintenance of sediment barriers.”

State water quality regulations require installation of black plastic sediment fences and hay bales around excavations to filter soil out of runoff, because excessive silt degrades the aquatic environment. Ranney said. In March 1999, he visited construction sites during rain storms to see how well the barriers work to prevent dirt from washing into nearby streams and rivers.

“Every time it stormed I went out,” he said. “I’d put on my rain gear and boots and go get wiped out in mud.”

He looked at building sites along major commercial corridors including Kingston Pike/Interstate 40 in Knox County and Highway 66 in Sevier County.

The study found effective sediment control at some locations — notably at Heritage High School in Blount County — but found that barriers at most sites were inadequately installed or maintained.

The worst problems overall were in Loudon County, where some excavations had gone unstabilized for two to three years in spite of regulations that give builders 30 days to stabilize idle sites, Ranney said.

The problems were not with the mandated barriers but with a lack of enforcement, he said.

“There are three people from the state who are responsible for overseeing 12 counties,” he said. “Those guys really are trying hard, but what can three people do.”

Without an active inspection program, he said that builders and architectural design firms have no incentive to follow state regulations rigorously.
Ranney also looked at streamside habitats in the vicinity of each excavation. He estimated that two-thirds of the habitats he inspected were being wiped out when contractors ditched, graded over or forced wet weather streams into buried culverts.