Macroinvertebrates, Watershed Imperviousness, and a Water Quality Index: A Confluence of Georgia Adopt-A-Stream’s Volunteer Data

Authors

Christopher H. Kodani, Clayton State UniversityFollow

Abstract

The relationship between a stream’s macroinvertebrate community as quantified by Georgia Adopt-A-Stream’s Water Quality Index and the impervious surface of an adopted stream’s watershed was weak. Although the average WQI decreased with increasing watershed imperviousness, the R² was only 8.3%--an admittedly poor fit. To further investigate, a more comprehensive analysis was performed using forward stepwise regression. This model, which included both imperviousness and the abundance of just 15 out of the 20 kinds of macroinvertebrates, achieved an R² of 59.4%. Imperviousness alone may not be a good predictor of WQI, but a combination of selected macroinvertebrate data and imperviousness can yield a better fitting model. Furthermore, mayflies, aquatic sowbugs, clams/mussels, midges, and lunged snails, all of which were excluded from the model because they did not have a significant predictive value for WQI, generally seem to have specific habitat requirements which are dictated by stream-reach, rather than whole watershed characteristics.

Acknowledgements

I would like to thank Clayton State University’s College of Arts and Sciences for their support of this work through a CASE grant, as well as the volunteers and professional staff of Georgia Adopt-A-Stream for the data upon which this study was based.

Recommended Citation

Kodani, Christopher H. (2021) "Macroinvertebrates, Watershed Imperviousness, and a Water Quality Index: A Confluence of Georgia Adopt-A-Stream’s Volunteer Data," Georgia Journal of Science, Vol. 79, No. 2, Article 3.
Available at: https://digitalcommons.gaacademy.org/gjs/vol79/iss2/3