SYNTHESIS OF THIRTY YEARS OF SURFACE-WATER QUALITY AND AQUATIC-BIOTA DATA IN SHENANDOAH NATIONAL PARK: COLLABORATION BETWEEN THE U.S. GEOLOGICAL SURVEY AND THE NATIONAL PARK SERVICE

Shenandoah National Park (SNP) is located in northern and central Virginia and consists of a long, narrow strip of land straddling the Blue Ridge Mountains. The park’s elevated topography and location downwind of the Ohio River Valley, where many acidic emissions to the atmosphere are generated, have made it a target for acid rain. Characterizing the link between air quality and water quality as related to acid rain, contaminants, soil conditions, and forest health is a high priority for research and monitoring in SNP. Shenandoah National Park natural resource managers showed abundant foresight by implementing an aquatic biota monitoring program well before SNP became a National Park Service Prototype Inventory and Monitoring Park in the early 1990’s. As a result of three different monitoring programs, a combined record of over three decades of data on water quality and biota in SNP cold-water riverine systems exists. Although the objectives of the programs differ, the common element that unites the three is water resources, therefore, some of the same water-quality parameters were collected for each effort. Inconsistent overlap among the three programs, however, resulted in spatially and temporally disparate data. The objective of the study was to integrate, analyze, and interpret the data to identify trends in stream-water quality and relations between aquatic fauna and stream-water chemistry. In general, stream-water quality and accompanying aquatic fauna were related to the underlying bedrock geology of the watersheds; the best stream-water quality and the healthiest communities of macroinvertebrates were found in streams underlain by bedrock that had the highest acid-neutralizing capacity. In contrast, stream water with lower pH and a depauperate macroinvertebrate community were underlain by bedrock with poor acid-neutralizing capacity.