1. General Model Information


Acronym: IMPACTS

Main medium: terrestrial
Main subject: biogeochemistry
Organization level: landscape
Type of model: not specified
Main application: decision support/expert system
Keywords: silviculture, water quality, sediment yields, spatially lumped, watershed scale, decision support system


J. Alan Clingenpeel
USDA Forest Service
Ouachita National Forest
PO Box 1270 Hot Springs, AR 71902
Fax : 501-321-5334


J. Alan Clingenpeel, Forest Hydrologist


IMPACTS is a simulation model that examines silviculture activities on water quality and fisheries at the watershed level. The model uses predicted sediment yields as a surrogate for impacts to water quality. The model calculates the average annual sediment values for the selected watershed. Sediment increases from presently occurring and proposed management alternatives are also calculated. The sediment values from presently occurring activities and proposed management alternatives are expressed as a percent increase over the average annual sediment produced from the watershed. This allows for a comparison of alternatives (expressed as a percent increase). The alternatives can also be compared to a threshold value associated with fisheries.

The model multiplies the number of acres associated with each land practice against a coefficient previously determined for that physiographic zone. The values from the land practices are summed to account for the entire watershed. Acreages are calculated from a 1:24,000 quad map (7 1/2 minute). Land practices are determined from aerial photos (same scale) or from on-site evaluation.

II. Technical Information

II.1 Executables:

Operating System(s): PC or a DG UNIX workstation

II.2 Source-code:

Programming Language(s): BASIC

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

V. Further information in the World-Wide-Web

VI. Additional remarks

Last review of this document by: T. Gabele: 07.07. 1997 -
Status of the document:
last modified by Tobias Gabele Wed Aug 21 21:44:45 CEST 2002

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