Chemical Composition of Precipitation and Watershed Samples Collected at Deep Creek Lake, Garrett County, Maryland - Third Annual Report

摘要

The objective of this study is to determine if acid deposition and acid mine drainage pose a significant threat to Deep Creek Lake, Garrett County, Maryland. Results of three years' study of rainwater at the site shows that the annual volume weighted mean pH of rain is 3.9 - 4.0. Hydrogen and sulfate ion concentrations are highly correlated and are comparable to those observed at nearby NADP sites. Concentrations of both ions are higher in summer rain, particularly for storms characterized by northwesterly winds. The summertime rain produces about 60% of the annual sulfate and H(+1) deposition at the Deep Creek site. Although rainwater nitrate concentrations were somewhat higher in summer than in other seasons, no significant correlations were seen between nitrate in rain and either rainwater pH or local wind direction. Studies of sequential rain fractions show there can be significant rapid changes in sulfate and nitrate concentrations within a single rain event.