Applications
The SWAS-VTSSS program has been maintained, in large part, to evaluate
the response of streams in the Appalachian region to ongoing decreases
in acid deposition (Fig. 1) stemming from the implementation of the 1990
Clean Air Act Amendments (Riscassi, Scanlon, & Galloway, 2019; Robison,
Scanlon, Cosby, Webb, & Galloway, 2013; Scanlon, Riscassi, & Galloway,
in review; Webb et al., 2004). Notably, a National Atmospheric
Deposition Program (NADP) site, which measures analytes in
precipitation, was established in 1981 in central SHEN (Fig. 2),
providing the data necessary to reliably quantify and assess changes to
watershed retention/export of individual ions through mass balance
calculations (Robison et al., 2013) and to gain insight into the
watershed characteristics responsible for regional differences in
recovery (Eng & Scanlon, in review). The physical and chemical data may
also be used to 1) identify driving factors of biological trends (e.g.
Blum, Kanno & Letccher, 2018), 2) determine the most appropriate
locations to investigate atmospheric pollutants, such as mercury, in
both aqueous (e.g. Riscassi & Scanlon, 2011) and biological (e.g.
Eagles-Smith et al., 2020) environments, 3) calibrate and
validate biogeochemical models for prediction of climate change impacts
(e.g. Robison & Scanlon, 2018), and 4) assesses the hydrologic and
chemical response to watershed disturbances such as insect defoliations
(e.g. Eshleman, Morgan, Webb, Deviney, & Galloway, 1998), catastrophic
flood events (e.g. Reinhardt & Furman, 2008), and fire (e.g. Jensen,
Scanlon, & Riscassi, 2017) (Fig. 1).