Geochemical modelling of acidification and recovery in forest soils and runoff waters

The Model of Acidification of Groundwaters in Catchments (MAGIC) was used to simulate the impact of acidifying deposition and future recovery at the Gårdsjön Covered Catchment Experiment, at a number of hypothetical stations defined by statistical variation of the Gårdsjön data and at 20 forest monitoring sites in Southern Sweden. For the future predictions a decrease of sulphur deposition of more then 70% was assumed. This assumption is based on a full implementation of the agreements made under the second sulphur protocol from 1994. The modelled impact of reduced deposition on the soils and on the runoff waters was discussed. To complement the discussion on long-term trends in future run-off chemistry, data from Gårdsjön has been used to asses the risk for short-term acid runoff episodes