Authors

Carnegie Mellon University
Mitchell Small
Rajarishi Sinha

E&S Environmental Chemistry
Tim Sullivan

Oak Ridge National Laboratory
Robb Turner

Science Applications International Corporation
Pat Ryan

University of Virginia
B. Jack Cosby

Summary

The Soils-Aquatics Effects Module uses information about acid (from the Atmospheric Pathways Module) to predict changes in the chemistry of lakes and soils.  In addition, changes in lake chemistry are used to estimate teh ability of the lakes in a region to support fish populations.  Varios indicators of fish viability have been implemented, which are subsequently used (in the Scenario Benefits Module) to estimate economic damaegs resulting from the loss of recreational fishing.    Responses to acid deposition predicted by TAF for lakes in teh test application region of the Adirondacks Park in New York are modest, as is the recovery associated with projected future deposition reductions.  However, these deposition reductions are indicated to be necessary to avoid continuing degradation of water quality and fish viability in some of the lakes.

Surface water and soil chemistry of watersheds are projected by reduced-form models, which are based on an approximation to the improved version of the Model of Acidification of Groundwater in Catchments (MAGIC, see Sullivan and Cosby, 1995a; Sullivan et al., 1995c).  MAGIC is a lumped parameter model that uses chemical equilibrium and mass balance equations to predict changes in lake and soil chemistry. The reduced-form models have been applied to lakes in the Adirondacks region of New York using a set of 33 lakes, chosen to be representative of the target population of lakes in the region.  The Aquatics Module predicts the effects of acidic deposition on lake and stream chemistry and resulting impacts on fish species.  The Soils Module projects the long-term effects that acidic deposition may have on the base saturation of soils.

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