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RESERVOIR RELEASE IMPROVEMENT Charles E. Bohac, Environmental Engineer E. Dean Harshbarger, Supervisor, Research and Testing Section Jack L. Davis, Program Manager, Reservoir Release Improvements Richard J. Ruane, Program Manager, Special Projects and Research Svein Vigander, Head, Fluid Systems Physical Analysis Group Division of Water Resources Tennessee Valley Authority Chattanooga, Tennessee 37401 BACKGROUND Reservoir releases are sometimes deficient in dissolved oxygen (DO) and streamflow needed to provide for assimilation of oxygen-demanding wastes. In addition, DO, flow and temperature might not be optimum for tailwater sport fisheries and other recreational activities. This chapter addresses the Tennessee Valley Authority's (TVA) investigations to improve the releases from a number of its reservoirs where such inadequacies exist. Results are presented on a feasibility analysis of alternatives and an experimental hydro- turbine aeration program. DO TRENDS The DO trend of the Tennessee River was evaluated by determining the average rate of change of DO over the time periods 1960-1979 and 1975-1979 [1]. Over the period 1960- 1979, all main stem reservoir releases showed decreases in DO except Fort Loudoun, Nicka- jack, Watts Bar and Chickamauga. These last four reservoirs actually had improved DO trends, possibly due to extensive pollution control efforts along the main stem and headwaters of the Tennessee River. For the 20-yr period 1960-1979, the mean DO concentrations in reservoir releases decreased by about 1.1-1.2 mg/1 at Kentucky and Pickwick, which are near the mouth of the Tennessee River, and increased about 0.3-0.4 mg/1 at Watts Bar and Fort Loudoun, near the headwaters. From 1975 to 1979, all main stem reservoirs but Chickamauga showed decreases in DO, indicating that perhaps the beneficial effects of wastewater cleanup programs have already peaked, and water quality may now be again on the decline. If the trend of the last five years prevails, DO levels in the main stem releases could decrease as much as 1.4- 1.7 mg/1 at Kentucky and Pickwick and 0.7-1.0 mg/1 at Watts Bar and Fort Loudoun in the next five years. Not all of the potentially significant variables were analyzed, and the results from trend analyses, especially for a short period such as five years, should be viewed with caution. Regardless of the trends, however, there are stream reaches within the TVA region which have periodic low DO at the present, and they are shown on Figure 1. POTENTIAL FOR DO IMPROVEMENT TVA reservoirs where the need for improved DO is most critical were identified and the potential improvement in DO was estimated assuming the use of several aeration methods currently under development by TVA and others. DO data for releases for the years 1970- 1979 were evaluated to determine: 1. the minimum observed dissolved oxygen concentration; 2. the average annual minimum DO; 847
Object Description
Purdue Identification Number | ETRIWC198287 |
Title | Reservoir release improvement |
Author |
Bohac, Charles E. Harshbarger, E. Dean Davis, Jack L. Ruane, Richard J. Vigander, Svein |
Date of Original | 1982 |
Conference Title | Proceedings of the 37th Industrial Waste Conference |
Extent of Original | p. 847-860 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-07-14 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 847 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | RESERVOIR RELEASE IMPROVEMENT Charles E. Bohac, Environmental Engineer E. Dean Harshbarger, Supervisor, Research and Testing Section Jack L. Davis, Program Manager, Reservoir Release Improvements Richard J. Ruane, Program Manager, Special Projects and Research Svein Vigander, Head, Fluid Systems Physical Analysis Group Division of Water Resources Tennessee Valley Authority Chattanooga, Tennessee 37401 BACKGROUND Reservoir releases are sometimes deficient in dissolved oxygen (DO) and streamflow needed to provide for assimilation of oxygen-demanding wastes. In addition, DO, flow and temperature might not be optimum for tailwater sport fisheries and other recreational activities. This chapter addresses the Tennessee Valley Authority's (TVA) investigations to improve the releases from a number of its reservoirs where such inadequacies exist. Results are presented on a feasibility analysis of alternatives and an experimental hydro- turbine aeration program. DO TRENDS The DO trend of the Tennessee River was evaluated by determining the average rate of change of DO over the time periods 1960-1979 and 1975-1979 [1]. Over the period 1960- 1979, all main stem reservoir releases showed decreases in DO except Fort Loudoun, Nicka- jack, Watts Bar and Chickamauga. These last four reservoirs actually had improved DO trends, possibly due to extensive pollution control efforts along the main stem and headwaters of the Tennessee River. For the 20-yr period 1960-1979, the mean DO concentrations in reservoir releases decreased by about 1.1-1.2 mg/1 at Kentucky and Pickwick, which are near the mouth of the Tennessee River, and increased about 0.3-0.4 mg/1 at Watts Bar and Fort Loudoun, near the headwaters. From 1975 to 1979, all main stem reservoirs but Chickamauga showed decreases in DO, indicating that perhaps the beneficial effects of wastewater cleanup programs have already peaked, and water quality may now be again on the decline. If the trend of the last five years prevails, DO levels in the main stem releases could decrease as much as 1.4- 1.7 mg/1 at Kentucky and Pickwick and 0.7-1.0 mg/1 at Watts Bar and Fort Loudoun in the next five years. Not all of the potentially significant variables were analyzed, and the results from trend analyses, especially for a short period such as five years, should be viewed with caution. Regardless of the trends, however, there are stream reaches within the TVA region which have periodic low DO at the present, and they are shown on Figure 1. POTENTIAL FOR DO IMPROVEMENT TVA reservoirs where the need for improved DO is most critical were identified and the potential improvement in DO was estimated assuming the use of several aeration methods currently under development by TVA and others. DO data for releases for the years 1970- 1979 were evaluated to determine: 1. the minimum observed dissolved oxygen concentration; 2. the average annual minimum DO; 847 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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