Estimation of mass balances of anions at a small catchment in a snowy area

Abstract

In order to estimate the impact of acid precipitation to aquatic ecosystems in snowy areas, the quality and quantity of both precipitation and stream water at a small experimental catchment (34.7ha) were studied. Using the observed data obtained during three years, balances of three kinds of acidic anions, those are Cl^-, NO₃^- and SO₄^2-, in the catchment were investigated. Accumulation and melting of snow had a strong influence on the movement of anions in the catchment. It was suggested that the effluent of meltwater with high anion concentration in the early stage of snowmelt might temporarily raise the anion concentration of stream water. Each anion exhibited different characteristics of outflow to the stream. The consumption of NO₃^- by biological activities and the production of SO₄^2-by weathering seemed to be the major factor for balances of anions in this catchment.