Abstract
The objective of this study was to investigate the flow dynamics and temperature characteristics under different reservoir operation scenarios and weather conditions in the river-reservoir system, which can be used to set scientific guidelines for river management and conservation planning strategies. The calibrated three-dimensional model provided simulated unsteady water surface elevation, temperature, velocity and discharge at different layers (depths) in different locations. A series of operation scenarios were modeled to understand and quantify formation, propagation, and disappearance of density currents that are resulted from combinations of daily repeated large release (DRLR) of different durations and solar heating. DRLRs (140 m3/s) with longer durations pushed the bottom cold water further downstream and maintained the bottom water temperature cooler. Variations of weather conditions (e.g., drops of air temperature and solar radiation) directly controled variations of bottom-layer water temperature. The daily drop rate of bottom temperature was related to the rate and duration of air temperature drop. Under the practice for the water turbines running at downstream, it clearly showed the shocking withdrawal and stopping effect from the downstream operation. The velocity for the whole cross-section were almost increased with same magnitude of about 0.1 m/s at GOUS and JML.
Highlights
Riverine ecosystems worldwide face multiple pressures due to human interventions such as dams, channelization, deforestation, and irrigation, as well as a plethora of industrial and agricultural waterborne emissions [1,2,13]
(2) A series of upstream reservoir operation scenarios were modeled to understand and quantify formation, propagation, and disappearance of density currents that are resulted from combinations of colder small releases, daily repeated large release (DRLR) of different durations from upstream reservoir operation, and solar heating
The study dealed with model simulations of flow and thermal dynamics in a river-reservoir system (124.2 river km) starting from Smith Dam Tailrace (SDT) to Bankhead Lock& Dam (BLD, about 23.5 m height and 426.7 m long) in Alabama (AL), USA (Figure 1)
Summary
Riverine ecosystems worldwide face multiple pressures due to human interventions such as dams, channelization, deforestation, and irrigation, as well as a plethora of industrial and agricultural waterborne emissions [1,2,13]. One major physical stressor on riverine ecosystems is thermal discharge from industrial facilities, which is problematic in and of itself and can aggravate the effects of chemical and biological pollution [4,7]. We tried to quantify the effect of climatic condition, release operations and thermal discharge to the natural river. Various upstream reservoir releases (management/operation patterns) were used to understand the unsteady flow patterns and temperature distributions in a river-reservoir system in Alabama, USA (Fig. 1). (1) Understanding flow dynamics and density current from the calibrated EFDC model which provided simulated unsteady water surface elevation, temperature, velocity and discharge at different layers (depths) in different locations. (3) Considering climate variations (warming or cooling scenarios), the upstream reservoir management scenarios to control the downstream water temperature for the power plant were further studied.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call