Before-and-after studies on the effects of a power-plant installation on Lake Lyndon B. Johnson. Before studies, Volume III. Temperature modeling. Final report to the Lower Colorado River Authority

Technical Report · Sun Jun 01 04:00:00 EDT 1975

OSTI ID:6438274

Fruh, E G; Maguire, B Jr; Schmidt, P S

The overall objective of this project is to determine the influence of Lower Colorado River Authority (LCRA) power plant operations on the Lake LBJ ecosystem. Phase I of this effort focussed on the behavior of the reservoir and its ecosystem before power plant operations began. A series of computer model studies carried out to predict thermal and hydrodynamic effects of the plant is summarized. A one-dimensional stratification model was developed to analyze the normal annual temperature variations in the reservoir without an artificial thermal input. Diffusion was found to be the dominant heat transport mechanism in the hypolimnion, while surface heat exchange and wind-induced mixing dominate in the epilimnion. Advection was not found to be particularly significant. The stratification model was two-dimensionalized to permit gradients in the horizontal plane, and the two-dimensional model was used to predict cooling rates for the far-field region of the thermal discharge. From the far-field studies, it was predicted that the discharge bay region of Lake LBJ will remain thermally stratified during most of the year, with a uniform surface layer six to twelve feet deep. During the warm months temperatures at the mouth of the bay may still be several degrees above ambient when the plant is operating at full load. A new-field model was used to attempt a prediction of thermal plume behavior in the region near the discharge channel. Despite several problems, some qualitative conclusions were obtained from the study; the model predicted that the plume would rapidly stabilize in depth, and that because buoyancy would inhibit vertical entrainment, the temperature gradient below the heated surface layer should be quite sharp.

• Research Organization: Texas Univ., Austin (USA). Center for Research in Water Resources
• OSTI ID: 6438274
• Report Number(s): CRWR-149; ON: DE83901434
• Country of Publication: United States
• Language: English

Related Subjects

520400* -- Environment
Aquatic-- Thermal Effluents Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AQUATIC ECOSYSTEMS
CIRCULATING SYSTEMS
COOLING
DISTANCE
DISTRIBUTION
ECOSYSTEMS
ENERGY TRANSFER
ENVIRONMENTAL IMPACTS
FEDERAL REGION VI
FOSSIL-FUEL POWER PLANTS
HEAT TRANSFER
INTERACTIONS
LAKES
LAYERS
MATHEMATICAL MODELS
MIXING
NORTH AMERICA
PLUMES
POWER PLANTS
SURFACE WATERS
TEMPERATURE DEPENDENCE
TEXAS
THERMAL EFFLUENTS
THERMAL POWER PLANTS
USA
WIND