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International Society for Environmental Information Sciences

Environmental Informatics Archives

ISSN 1811-0231 / ISEIS Publication Series Number P002

Copyright © 2006 ISEIS. All rights reserved.



  Paper EIA06-037, Volume 4 (2006), Pages 408-418 = complimentary

Drought Induced Dissolved Oxygen Dynamics of an Effluent Dominated Stream Entering a Reservoir Backwater and Implications for Environmental Compliance

R. D. Taylor1*, K. L. Dickson2 and V. Golla2

1. Western Kentucky University, Department of Public Health, Environmental Health Science, 1906 College Heights Blvd., Bowling Green, KY 42104. *Corresponding author: ritchie.taylor@wku.edu.

2. University of North Texas, Institute for Applied Sciences, P.O. Box 310559, Denton, TX 76203.



Compliance with dissolved oxygen standards is the basic means for assessing wastewater treatment plant discharges of oxygen demanding wastes.  Methods often consist of collecting water quality samples at or near the critical low flow condition during the summer season, such as the 7-day average flow with a 10-year recurrence interval (7Q10), and developing a water quality model set that adequately represents the empirical data.  In the analysis of effluent dominated streams entering reservoirs, the critical event may be defined not only by stream flow conditions but receiving water characteristics, such as the location of the transition zone from stream to reservoir dynamics.  This zone is often the stated location for compliance with water quality standards.  Drought induced changes in reservoir storage can change the longitudinal extent of stream transition zones.  Fluctuating reservoir levels cause concurrent variations in stratified backwater conditions and dissolved oxygen values.  By assessing the variability in daily dissolved oxygen values the boundaries of the stream/reservoir transition zone can be identified.  The determination of the transition zone is critical to accurately assess compliance with dissolved oxygen water quality standards.  Daily variations in dissolved oxygen are used to model the location of the transition zone for water quality compliance, as compared to drought induced reservoir fluctuations.  Results indicate that site specific water quality measurements are needed to accurately define environmental compliance monitoring locations in effluent dominated streams entering reservoirs.

Keywords: wastewater, dissolved oxygen, water quality, effluent, drought, effluent dominated stream, reservoir, environmental compliance, NPDES


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