Cary Institute of Ecosystem Studies, Environmental Monitoring Program, Stream Chemistry Data

Stream samples were collected at the end of every month at two sites on the East Branch of Wappinger Creek at the Cary Institute of Ecosystem Studies. Before 1996, samples were collected at four sites. Redundancy in the data and cost of analysis prompted us to discontinue collecting samples at two of the sites. The two remaining sites are Site 2 (Fern Glen, GPS coordinates N41.78707, W73.73317) and Site 4 (Lowlands, GPS coordinates N41.79235, W73.74937). Sample collection began in November 1985 (Site 2) and January 1985 (Site 4). Samples were collected when the stream was as near base flow as possible; however, base flow varies seasonally and was generally higher in winter than summer. The samples were analyzed at the Cary Institute Analytical Laboratory for pH, conductivity, NO3-, SO4-2, NH4+, PO4-3, Cl-, Na+, Ca+2, Mg+2, K+ and SiO2 and DOC (see http://www.caryinstitute.org/empdata/metadata/meta_analytable.htm for analytical methods). Samples collected between 1985 and 1998 were not preserved in any way and were stored in the light at room temperature before analyses were completed. Samples from January 1999 onward were preserved as follows. Samples were divided into three aliquots, one aliquot was filtered and preserved with Optima grade concentrated sulfuric acid (0.5 ml per 125 ml of sample) for analysis of NO3-, NH4+, PO4-3, and DOC. Another aliquot was filtered and analyzed for SO4-2, Cl-, Na+, Ca+2, Mg+2, K+ and SiO2. SiO2 analyses were completed within 4 days of sample collection. The third aliquot was untreated and analyzed for conductivity and pH.