The model SMART was calibrated to the lakes of the Finnish network of monitoring acidification. For the calibration available regional data on acidifying deposition (from the DAIQUIRI model), base cation deposition (deposition monitoring network), forest soils (soil surveys), and catchment characteristics (lake surveys) were combined. The regional model calibration was performed by calibrating SMART individually for each of the 172 lakes. It was attempted not only to fit the present values of soils and waters, but also to fit the overall 10-year water quality trend of the lakes. In the calibration procedure the data was estimated and adjusted for each lake by:
- using the observed lake chemistry to scale the acidifying deposition, and
- assigning the nearest soil sampling site properties to the catchment soil parameters.
Nine lakes could not be calibrated with this procedure and they were excluded from further investigation. Once the remaining 163 lakes were successfully calibrated, the parameter set for each lake was used to simulate future water chemistry. The results demonstrate that the acidification in these sensitive lakes will proceed very slowly, if at all, during the next 50 years. Assuming the current reduction plans (CRP-scenario), there is a deterioration of water quality in eastern Finland influenced by emissions from the Russian Federation. In case the deposition will be reduced even further from the current reduction plans (MFR-scenario) there will most likely be a slow recovery. If the base cation deposition is still to be reduced the recovery from acidification may not take place.
Three maps of Finland showing the location of the modelled lakes with their ANC status for the present (1990) and for two scenarios in 2050 (Current Reduction Plan (CRP) and Maximum Feasible Reduction (MFR)). In the Current Reduction Plan (CRP) scenario the future deposition of sulphate is derived from 2010 emissions according to the Second Sulphur Protocol (UN/ECE, 1994), and the deposition of nitrogen is assumed to stay at the present level. In the lower MFR scenario, the depositon of sulphur is based on maximum technically feasible reductions, and the deposition of nitrate declines by 30% by the year 2010. The deposition of ammonia , base cations and chloride stay at present level for both scenarios.
Contact point e-mail: Juha.Kamari@vyh.fi or emir.bilaletdin@vyh.fi
