Water flow paths and the spatial distribution of soils as a key to understanding differences in streamwater chemistry between three catchments (Norway)

Abstract

Here results are presented of a hydrochemical study at a pristine and two acid rain-impacted catchments in Norway. An analysis of streamwater chemical data interpreted as mixtures of observed soil solutions, is combined with data on the spatial distribution of soils. The analysis reveals that at all three sites low flow streamwater is dominated by groundwater, relatively rich in base cations, originating from the peat bogs adjacent to the brook. By contrast, high flow largely originates in catchment-specific acidic soil horizons on the hill slopes. Results indicate that short-term and long-term hydrochemical responses to acid deposition may differ between catchments which at first glance have a ‘similar’ make up of acidic soils. This illustrates the difficulty in selecting appropriate sites for comparative studies of the effect of acid atmospheric deposition on the chemistry of streamwater.