Modeling Long-term Streamwater Chemistry in the Berg Catchment, Southwestern Sweden

The geochemical model MAGIC (5.01) was applied to the Berg – Pipbäcken Nedre catchment in southwestern Sweden for the period 1846-2020. The major objective was to reconstruct historical acidification trends and predict the surface water and soil response to declining atmospheric deposition in the future based on the Gothenburg Protocol signed in 1999. Another task was to test the usefulness of Sweden's long-term small catchment monitoring program for a validation of the long-term acidification model. Berg has been one of fifteen catchments monitored very intensively by the Swedish Environmental Protection Agency during 1986-1993 and less intensively later by the Swedish University of Agricultural Sciences Department of Environmental Assessment. Anthropogenic atmospheric deposition was the dominant factor causing a decline of streamwater pH and especially soil base saturation. A scenario of future atmospheric deposition based on the emission reductions of S and N compounds agreed under the 1999 Gothenburg Protocol to the UNECE CLRTAP was modeled. This scenario stopped further acidification of soils, but recovery of streamwater pH and soil base saturation was slow and limited. Without further reductions from the deposition levels in 1995-1997, soil acidification would continue.