Data for Virginia’s wild brook trout streams now available online

Laurel Fork

Stream water chemistry data are now available online at http://swas.evsc.virginia.edu for most wild brook trout streams in the western Virginia mountains.

The data are part of the Mountain Stream Database, which provides data collected during the last 25 years by the Shenandoah Watershed Study and the Virginia Trout Stream Sensitivity Study (SWAS-VTSSS). Both programs were begun by and are managed by the Department of Environmental Sciences at the University of Virginia.

The purpose of SWAS-VTSSS research and data collection is to evaluate the effects of acidic deposition (acid rain) and other ecological stressors (e.g., climate change) affecting Virginia brook trout streams. The Mountain Stream Database and related documents are posted on the SWAS-VTSSS website.

Development of the Mountain Stream Database was funded by the Appalachian Stewardship Foundation, which supports projects focused on energy and environmental quality in the Appalachian region.

The database includes chemical analysis results for streams sampled in regional trout stream surveys conducted in 1987, 2000, and 2010 with the assistance of Trout Unlimited and other conservation groups and natural resource management agencies. Data are also provided for a subset of trout streams that have been sampled quarterly since 1987. In total, data are provided for 461 streams in 34 counties.

A map of the SWAS-VTSSS sampling sites.

A map of the SWAS-VTSSS sampling sites.

The database provides data tables and site-location maps for all sample sites, plus graphic data displays for quarterly sample sites. The data include pH and acid neutralizing capacity, plus concentrations of the major dissolved chemical compounds found in regional mountain streams. One of these, sulfate, is primarily derived from sulfur emissions at coal-burning power plants. The presence of elevated sulfate concentrations in Virginia mountain streams is an indicator of acidic deposition exposure.

In recent decades, sulfur emissions from power plants have declined dramatically in response to Clean Air Act requirements. From a peak level in the 1970s, sulfur emissions have now declined to the lowest level since 1900. This reduction represents one of the major environmental success stories of our time.

The good news, however, does not extend to all of Virginia’s mountain streams. Although decreased sulfate concentrations are associated with recovery from acidification in many streams, a large subset of streams is not showing a positive response. As described in interpretive material presented on the SWAS-VTSSS website, there has been little recovery for most of the more-acidified streams. This can be attributed to the cumulative damage to watershed soils caused by past decades of acidic deposition.

For more information about the SWAS-VTSSS Program, contact Rick Webb at rwebb@nullvirginia.edu or 540-468-2881.

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The Virginia Council of Trout Unlimited is made up of representatives of the state’s 16 TU chapters.