View the Report

From the report:

"For over five years, with public and private support, with the involvement of governmental and non-governmental sponsors, with the guidance of expert scientists, and with the help of scores of dedicated volunteers, StreamWatch has been conducting biological surveys at dozens of monitoring sites throughout the Rivanna River watershed. The creatures we collect - insects, snails, worms, and such - are environmentalindicators. Their presence, absence, and relative abundance tell us about water quality and habitat conditions, and through analysis of multiple samples, StreamWatch is able to gauge our waterways' ability to support life and provide services to our human community. In this, our third report, we assess biological health at 31 representative sites based on three years of data ending in fall 2007. The summary you are now reading is distilled from a comprehensive report available at our website: www.streamwatch.org/reports.

Findings
Three-quarters of representative stream sites failed the Virginia aquatic life water quality standard. Failure means the community of organisms in the stream is at least moderately degraded due to human-related stressors.

The condition of most failing sites lies near the pass/fail cusp. These streams have a reasonable chance of regaining good health in response to improved stewardship. Conversely, most passing streams also lie near the cusp, and could fail in response to neglect. Four of 31 sites (13%) are badly impaired.

The percentage of failing sites is slightly higher than in our previous report. Evidence suggests that drought in 2006 and 2007 may have piled additional stress on streams already burdened by human disturbance. However, we do not have a long enough data record to test this theory.

As with previous StreamWatch reports, we see a strong relationship between stream health and land use intensity. StreamWatch has been monitoring the Rivanna system for five years, during which time land use in parts of the watershed has changed. But the change has not been extensive enough to affect the overall biological health of the stream network, at least not in a way that our monitoring system can detect.

Biological health at our monitoring station on Middle Fork Cunningham Creek has declined quite noticeably."