Water, Air, and Soil Pollution

, Volume 105, Issue 3, pp 617-642

First online:

Reduced-Form Modelling of Surface Water and Soil Chemistry for the Tracking and Analysis Framework

  • R. SinhaAffiliated withDepartment of Civil and Environmental Engineering, Carnegie Mellon University Email author 
  • , M. J. SmallAffiliated withDepartments of Civil and Environmental Engineering and Engineering and Public Policy, Carnegie Mellon University
  • , P. F. RyanAffiliated withScience Applications International Corporation
  • , T. J. SullivanAffiliated withE&S Environmental Chemistry, Inc.
  • , B. J. CosbyAffiliated withDepartment of Environmental Sciences, University of Virginia

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A reduced-from modelling approach is used to predict soil and lake acidification as part of an integrated assessment of acid deposition effects and control strategies. The reduced-form model is based upon the mechanistic, lumped parameter watershed chemistry model, MAGIC (Model of Acidification of Groundwater in Catchments). Recent improvements to MAGIC are described, and its reduced-form representation in the Tracking and Analysis Framework (TAF), an integrated assessment model for decision and uncertainty analysis, is presented. Reduced-form models are developed for lake acid neutralising capacity (ANC), calcium, pH, and aluminium; and for soil base saturation. The model for lake ANC incorporates long-term depletion of the watershed acid neutralisation fraction, as is predicted to occur with MAGIC. In test calibrations for 33 representative watersheds in the Adirondacks, the resulting reduced-form model provides a close approximation to MAGIC, with average root mean square errors of 0.79 μeq l-1 for ANC, 1.09 μeq l-1 for calcium, 0.16 for pH, 2.52 μeq l-1 for aluminium, and 0.09% for soil base saturation. In addition, improved fish viability models are incorporated in the integrated assessment model, and predictions are demonstrated for a future deposition reduction scenario for the Adirondack region.

acid deposition Adirondacks integrated assessment lake acidification mathematical model reduced-form modelling soil acidification