Abstract
An integrated, interdisciplinary, intensive study of three forested watersheds was started in 1977 to quantify the relationship between the deposition of atmospheric acids and surface water acidity. Results indicate the importance of using an integrated ecosystem perspective to assess the vulnerability of surface waters to acidification and the value of analysing relative flowpath contributions to understanding surface water alkalinity levels and dynamics. Important ecosystem properties affecting surface water acidity are soil depth, soil mineralogy and stage of forest development.