Stream Monitoring Program
The Shenandoah Watershed Study (SWAS) was founded by Dr. James Galloway,
Dr. George Hornberger and Dr. Roger Pielke, as a joint program between
the University of Virginia Environmental Sciences Department and
Shenandoah National Park (SHEN), to assess watershed response to
elevated acid deposition in the central Appalachian region. In 1979,
SWAS established its first site in SHEN for weekly stream water sample
collection and analysis of acid-base chemistry and stream discharge
monitoring. The water chemistry monitoring program was spatially
expanded in 1987 with the initiation of the Virginia Trout Stream
Sensitivity Study (VTSSS) which, in collaboration with the Virginia
Department of Game and Inland Fisheries (VDGIF) (recently renamed
Virginia Department of Wildlife Resources, VDWR) and Trout Unlimited
(TU) citizen volunteers, sampled the majority of native brook trout
streams (Salvelinus fontinalis ) in Virginia. Results from the
state-wide trout stream survey determined that the chemical response to
acid deposition is primarily mediated by underlying bedrock (Sullivan,
Webb, Snyder, Herlihy, & Cosby, 2007; Webb, Cosby, Galloway, &
Hornberger, 1989). This point-in-time assessment informed a quarterly
stream water sampling scheme for a geographically and
geologically/chemically stratified subset of 72 sites (Webb et
al., 2004). Further spatial and temporal expansion of the SWAS program
occurred in the early 1990’s in conjunction with the Fish in Sensitive
Habitats (FISH) program (Bulger et al ., 1995), with 6 sites
throughout SHEN sampled weekly by 1992. A subset of 3 weekly sites
(hereafter ‘intensive sites’), representing the range of sensitivity to
acid deposition, were selected for streamflow monitoring and event-based
sampling necessary to assess high-flow chemistry/episodic acidification
(Eshleman, Miller Marshall, & Webb, 1995; Hyer, Webb, &
Eshleman, 1995). In addition to maintaining the episodic, weekly
and quarterly sampling until present, the SWAS program further advanced
temporal monitoring in 2014/2015 with the incorporation of in-situ
high-frequency air and water temperature and conductivity sensors at the
3 intensive sites. The state-wide VTSSS water quality survey (hereafter
‘decadal survey’) has been repeated in 2000, 2010, and is planned for
2021. A timeline of the SWAS-VTSSS program is presented in Figure 1.