SEASONAL-VARIATIONS IN ACID-NEUTRALIZING CAPACITY IN 13 NORTHEAST UNITED-STATES HEADWATER STREAMS

Variations in acid-neutralizing capacity (ANC) in 13 streams in the Ad irondack, Catskill, and Northern Appalachian Plateau regions of the no rtheast United States were related to discharge, time of year, and sea sonal variations in cation and anion concentrations using periodic reg ression analysis. ANC varied significantly with both discharge and tim e of year in 12 streams. Generation of ANC seasonal variations, being dependent upon the precise timing and magnitude of seasonal variations in cation and anion concentrations, was unique to each stream. Greate st seasonal ANC variations occurred in streams where seasonal variatio ns in major anion and cation concentrations were completely out of pha se. Maximum errors that could occur because of extrapolation of ANC da ta from one time of year to another were equal to or greater than maxi mum errors due to extrapolation of ANC from one discharge to another.