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Communication at the NABS Annual meeting, Keystone, 2000
(231) TECHNICAL ISSUES FOR DEVELOPING BIOCRITERIA IN URBAN SYSTEMS.
M.T. Barbour and J.B. Stribling. Tetra Tech, Inc., 10045 Red Run Blvd., Suite 110, Owings Mills, MD 21117
Urbanized watersheds represent ecosystems heavily influenced by cumulative stressors resulting from extensive land cover conversions. For example, residential, commercial, and industrial development result in decreased coverage of natural vegetation, increased imperviousness, the associated alteration of streamflow characteristics and increased rates of erosion, and varying levels of chemical stressor input via point source discharges, atmospheric deposition, or nonpoint source runoff. These systems are severely altered from what can be expected in relatively undisturbed watersheds. State water quality standards impose levels of attainment for all water bodies, including urban systems, and biocriteria are part of those standards. The primary issue is what is attainable in urban systems where socioeconomic decisions have been made to permanently alter the watersheds. Examples of studies where we designed bioassessment to play a key role in environmental decision making include the Counties of Prince George's in Maryland, Dade County in Florida, and Rockdale County in Georgia. In all of these situations, the decision of what constitutes an appropriate reference condition was crucial. Reference conditions are not specifically developed for urban or otherwise altered streams. However, in all three counties, urban streams are assessed as being at some level of comparability to minimally-impacted regional expectations.
Presented at 8:30 AM on Thursday, June 1, 2000 in Application of Biocriteria / Standards to Highly Stressed Rivers and Streams
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