Rivanna streams in fair health

By JULIE STAVITSKI / Daily Progress staff writer
Originally published: October 24, 2004

The Rivanna basin stream network is in fair health, though streams close to Charlottesville’s urban center are severely deteriorated, according to a report released by a local ecological monitoring program.

Additionally, a high correlation between heavy land use and stream health was confirmed in the group’s findings.

StreamWatch, a local data collection and stream monitoring program, published the results of its first 18-month study that found that two-thirds of 21 area stream sites are in fair condition.

“It’s more or less what those of us who are familiar with water quality would expect,” Program Director John Murphy said.

Findings were based on the variety and amount of benthic macroinvertebrates in the streams, which were sampled at least three times from winter 2002 to spring 2004.

“Focusing on biological sampling measures something of critical importance: the stream’s ability to support life,” Murphy said.

Murphy said the variety of invertebrates is a very good measure of biological health: If a stream has more stress-tolerant bugs, such as caddis flies or aquatic earthworms, then the stream is in poor condition.

Mayflies and stoneflies, which are more sensitive organisms, are indicative of a healthy stream approaching “natural conditions.”

Moore’s Creek and Meadow Creek in the city were found to be in very poor condition.

“Meadow Creek is about what you’d expect,” Murphy said.

With Moore’s Creek, the sampling station was close to Woolen Mills, a high-density development area, which may have contributed to the stream’s low score, Murphy said.

Both streams have been designated impaired by the Virginia Department of Environmental Quality.

The study’s findings also reveal that if there is a large amount of impervious surfaces surrounding a stream, such as roads, then the variety of invertebrates in the stream is likely to be low.

“Proximate land use has a strong impact,” Murphy said.

Most streams in the area were designated fair, which StreamWatch defines as “Somewhat Degraded,” meaning the number of sensitive invertebrates has decreased and the proportional population of stress-tolerant organisms has increased.

“To say something is in fair condition is acknowledging that we are here and utilizing resources,” Murphy said. “There is an impact. The question is, how far do we want to go with these impacts?”

While StreamWatch does not make recommendations as to how to remedy the impacted streams, Murphy said members of the organization’s steering committee agree on the study’s results.

“It gives us, as a community, some real benchmarks,” Murphy said. “These are findings that all organizers are standing behind.”

Alyson Sappington, district manager for the Thomas Jefferson Soil and Water Conservation District and a StreamWatch steering committee member, said the findings could help influence how the district focuses its urban and agricultural outreach programs.

Contact Julie Stavitski at (434) 978-7237 or jstavitski@dailyprogress.com.

© 2004 Media General