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Using Streamflow as a Predictor of Biotic Health in the Upper Oconee Watershed
Citation:
Sterling, J. AND B. RASHLEIGH. Using Streamflow as a Predictor of Biotic Health in the Upper Oconee Watershed. Presented at 2009 Georgia Water Resources Conference, Athens, GA, April 27 - 29, 2009.
Impact/Purpose:
see description
Description:
Macroinvertebrates are commonly used as biological indicators of stream habitat and water quality. Chronic reduced streamflows can have a significant impact on biota, decreasing in-stream habitat and influencing water quality. Many aquatic macroinvertebrates are sensitive to changes in water chemistry, and streams with degraded water quality are often characterized by low macroinvertebrate diversity. A previous study by the Upper Oconee Watershed Network related the Georgia Adopt-A-Stream biotic index for macroinvertebrates to water chemistry (Kominoski et al., 2007), but did not consider the effects of streamflow, which may also influence index scores. In this study, we used multiple measures of flow (including seasonal mean and variability) from USGS gage data to examine patterns in the macroinvertebrate index for seven tributaries of the North and Middle Oconee Rivers in Clarke County, Georgia. Macroinvertebrate samples were collected seasonally from 2000-2008 and scored using the Georgia Adopt-A-Stream biotic index. Statistical analyses suggest that streamflow is a significant predictor for the biotic index. The index appears to have a peaked response to streamflow and a negative response to flow variability. These results provide insight to the factors structuring benthic macroinvertebrates communities in urban streams in the Oconee River basin, and may guide the use of this index for bioassessment throughout the state of Georgia.