A 19-year record of chemical and isotopic composition of water from springs of the Shenandoah National Park, Virginia, 1995-2014

During October 1995 through March 2014, the U.S. Geological Survey in cooperation with the National Park Service, Luray, Virginia Station collected and analyzed samples of selected springs, air and unsaturated-zone gases in Shenandoah National Park, Virginia. The 19-year record of measurements of chemical and isotopic composition of water discharging from 34 springs located along the crest of the Blue Ridge Mountains in Shenandoah National Park, Virginia, is reported. These data include field measurements of water temperature, specific conductance, concentrations of dissolved oxygen (O₂), and pH. Laboratory measurements included major-, minor-, and trace-element chemistry; concentrations of dissolved gases (nitrogen, [N₂] argon [Ar], oxygen, and carbon dioxide [CO₂]); concentrations of dissolved trace atmospheric gases, including trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), and trichlorotrifluoroethane (CFC-113) and sulfur hexafluoride (SF₆); and hydrogen stable isotopic composition (δ²H) and oxygen isotopic composition (δ¹⁸O) of water. The data include an up to 14-year time series record of monthly sampling at five springs collected between 1995 and 2013. The measurements included temperature, specific conductance, pH, and discharge recorded at 30-minute intervals. Atmospheric mixing ratios of CFC-11, CFC-12, CFC-113, trifluorobromomethane (CF₃Br), SF₆, and trifluoromethyl sulfur pentafluoride (SF₅CF₃) in air from the Big Meadows Air Monitoring Station, Shenandoah National Park, were measured at approximately weekly intervals from September 1995 through March 2014.

Additional data include monthly (between May 2001 and August 2003) measurements of temperature, N₂, O₂, Ar, CO₂, CFC-12, CFC-11, CFC-113, and SF₆ concentrations in unsaturated-zone air from seven multilevel piezometers in Shenandoah National Park and at the U.S. Geological Survey National Center in Reston, Virginia. All samples were analyzed at the U.S. Geological Survey Laboratories in Reston, Virginia.