Adirondack headwater lake chemistry relationships with watershed characteristics

The surface waters of the Adirondack region of New York state were sensitive to acidic deposition and the area received large annual inputs of acidic deposition. Studies were carried out to establish why some lakes in a particular region acidified and others did not. The Adirondack Catchment Database contained information on lake chemistry, elevation, area and volume and associated catchment data such as size, slope, aspect, elevation, vegetation and wetland types, beaver activity, fire and logging history and soils data. The relationships between catchment attributes and lake chemistry were studied using bivariate and multivariate procedures. There were indications that wet deposition, lake elevation and forest cover were the main variables associated with variance in data for lake pH and with acid neutralizing capacity (ANC) in the Adirondacks. Relationships developed by statistical analysis were used to predict the acidity of other lakes in the area for which data did not exist. About 50 per cent of the headwater lakes in the region had a total ANC of less than 40 ueq per litre and 40 per cent had a pH less than 5.5