Accurate predictions of acid precipitation effects on water resources are important in order to allow a better understanding of various pollution control strategy outcomes. Dynamic geochemical models have been developed to address this need, but have to be tested under a variety of environmental conditions to provide confidence in their predictions. The most commonly used aquatic acidification model in North America and Europe is the model of acidification of groundwater in catchments (MAGIC). Though extensively used, MAGIC has never been tested in catchments with extremely low ionic strength water and high in natural organic acids (NOAs) from wetlands, two conditions which are common in large parts of Canada. We calibrated the model for two catchments located in Nova Scotia, Canada, which had some of the most dilute freshwaters reported in the literature and very high NOA. We also evaluated the variability inherent in calibration data sets by using five separate data sets collected over a 15-year period at the same sites. We show good model simulations for the main cations and anions in catchment waters. However, modeling pH is more difficult in the highly organic waters and requires modification to the acid dissociation constants. Calculated acid neutralization capacity can also be more difficult to model due to the low ion content making small errors more important. In theory, multiple calibrations of a model at a same site should produce identical hindcasts and predictions. In reality, the multiple calibrations produced a series of similar, but not identical outcomes which give a probable range of past values and future outcomes. We feel that this practical approach to validation is a useful addition to the arsenal of model testing tools.
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References
B.L. Beattie, K.N. Keddy and K.A. Luedemann, Trends in acid deposition in the Atlantic Provinces (1980–1998), Science Report Series 2000–02, Meteorological Service of Canada, Atlantic Region, Dartmouth, Nova Scotia, Canada (2000) 30 pp.
T.A. Clair, T.L. Pollock, P. Collins and J.R. Kramer, How brownwaters are influenced by acidification: the HUMEX lake case study, Environ. Int. 18 (1992) 589–596.
T.A. Clair, J.M. Ehrman, A.J. Ouellet, G. Brun, D. Lockerbie and C.-U. Ro, Changes in freshwater acidification trends in Canada's Atlantic Provinces: 1983–1997, Water, Air, Soil Pollut. 135 (2002) 335–354.
B.J. Cosby, R.F. Wright, G.M. Hornberger and J.N. Galloway, Modeling the effects of acid deposition: assessment of a lumped parameter model of soil water and streamwater chemistry, Water Resour. Res. 21 (1985) 51–63.
B.J. Cosby, R.F. Wright, G.M. Hornberger and J.N. Galloway, Modeling the effects of acid deposition: estimation of long-term water quality responses in a small forested catchment, Water Resour. Res. 21 (1985) 1591–1601.
B.J. Cosby, G.M. Hornberger, J.N. Galloway and R.F. Wright, Time scales of catchment acidification: a quantitative model for estimating freshwater acidification, Environ. Sci. Technol. 19 (1985) 1144–1149.
B.J. Cosby, R.C. Ferrier, A. Jenkins and R.F. Wright, Modelling the effects of acid deposition: refinements, adjustments and inclusion of nitrogen dynamics in the MAGIC model, Hydrol. Earth Syst. Sci. 5 (2001) 499–517.
B.J. Cosby, R.F. Wright and E. Gjessing, An acidification model (MAGIC) with organic acids evaluated using whole-catchment manipulations, J. Hydrol. 170 (1995) 101–122.
C.T. Driscoll, R.D. Fuller and W.D. Schecher, The role of organic acids in the acidification of surface waters in the Eastern U.S., Water, Air, Soil Pollut. 43 (1989) 21–40.
B. Freedman and T.A. Clair, Ion mass balances and seasonal fluxes from four acidic brownwater streams in Nova Scotia, Can. J. Fish. Aquat. Sci. 44 (1987) 538–548.
D.R. Marmorek, G.L. Lacroix, J. Korman, I. Parnell and W.D. Watt, Assessing the impacts of acidification on Atlantic Salmon (Salmosalar): a simple model of stream chemistry, Can. J. Fish. Aquat. Sci. 55 (1998) 2117–2126.
T. Page, K.J. Beven, J. Freer and A. Jenkins, Investigating the uncertainty in predicting responses to atmospheric deposition using the Model of Acidification of Groundwater in Catchments (MAGIC) within a Generalised Likelihood Uncertainty Estimation (GLUE) framework, Water, Air, Soil Pollut. 142 (2003) 71–94.
C.-U. Ro, R.J. Vet and D. Ord, Canadian Air and Precipitation Monitoring Network (CAPMoN) Annual Summary Reports (1983–1997). Environment Canada, Atmospheric Environment Service (1998).
R.W. Shaw, Environ. Sci. Technol. 13 (1979) 406–411.
Acknowledgements
Dr. C.-U. Ro Meteorological Service of Canada provided the CAPMoN deposition data. Mr. Floyd Luxton of Maitland Bridge, Nova Scotia, carefully collected both precipitation and water chemistry samples for 18 years. The Environmental Quality Laboratory of Environment Canada, Moncton, New Brunswick, completed all the water chemistry analyses used in this work. This study was funded by Environment Canada's Acid Rain program.
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Dennis, I.F., Clair, T.A. & Cosby, B.J. Testing the MAGIC acid rain model in highly organic, low-conductivity waters using multiple calibrations. Environ Model Assess 10, 303–314 (2005). https://doi.org/10.1007/s10666-005-9010-x
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DOI: https://doi.org/10.1007/s10666-005-9010-x