Determining the influence of habitat and chemical factors on instream biotic integrity for a Southern Ohio watershed

Abstract

The relative influences of water quality and in-streamhabitat on receiving water biology were investigatedin the Little Miami River, Ohio, a national and statescenic river located in the southwest corner of thestate. Monitored sample data for water chemistry,habitat, invertebrates and fish were obtained fromfederal and state sources and integrated via ageographical information system (GIS), using a uniquestream segmenting system. Locations and flowinformation for municipal wastewater treatment plants(WWTPs) were also integrated into the system. Therelative importance of water chemistry and habitat onbiological sample information was determined usingmultivariate forward stepwise regression. Theprincipal environmental factors that influencedbiological responses were in-stream habitat andpercent cumulative WWTP effluent at mean flow. Cumulative WWTP effluent at low flow dilution,nutrients and total toxic units from metals andammonia did not correlate with biological responses(e.g. number of mayfly species, invertebrate communityindex (ICI), number of fish species and index ofbiotic integrity (IBI)). We found the GIS-based datamethods to be highly useful for understanding theprincipal processes that guide receiving water health.