Using GIS and Land Use Data to Select Candidate Reference Sites for Stream Bioassessment

244 Pages·2002·7.2 MB·English

by  Olson, John Robert

Columbus State University
The College of Science
The Graduate Program in Environmental Science
Using GIS and Land Use Data to Select Candidate Reference
Sites for Stream Bioassessment
A Thesis in
Environmental Science
by
John Robert Olson
Submitted in Partial Fulfillment
of the Requirements
for the Degree of
Master of Science
May 2002
©
2002 by John Robert Olson

have submitted this thesis in partial fulfillment of the requirements for the
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degree of Master of Science.
Date John Robert Olson
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We approve the thesis of John Robert Olson as presented here.
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Date /Vannes A. Gore, Professor of
invironmental Science, Thesis Advisor
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Date StenrTDrStokes, Professor of Biology
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Date Thomas B. Hanley, Professor of
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ABSTRACT
GIS was used to select candidate reference sites in Georgia to characterize
the reference condition by sub-ecoregion for a rapid bioassessment of streams
statewide. Instead of relying on best professional judgment or previous
knowledge of a limited number of sites, we performed an objective evaluation of
cumulative impact on all catchments using land use data sets. These included
road and impoundment data from DLGs and Multi-Resolution Land use
Consortium data. Land use impairment was measured as percentages of forest,
urban, pasture, row crops, and barren area for both the entire catchment and for
10, 40, and 130-m riparian buffers, road and impoundment density and
stream/road crossings. Sites were then ranked by land use impairment, with the
least impaired selected as candidate reference sites. The larger buffers,
impoundment density, and stream/road crossing criteria were the least able to
predict minimal impact, and were weighted less. Water chemistry, benthic
macroinvertebrates, and physical habitat results demonstrated that 74% of the
sites selected using this method met reference site criteria of other states. These
data also demonstrated that these sites were equal to, or better than, sites
identified by using best professional judgment. Possible reasons for the
misidentification of sites are changes in land use since the data collection and
the lack of a direct correlation between moderate human land use and stream
habitat impairment.