Modeling Hydrothermal Response of a Reservoir to Modifications at a High-Head Dam

Abstract Pronounced stratification and peaking operation, typical of reservoirs impounded by high-head dams, result in complex current patterns. These cause disorientation in downstream migrating salmon and interfere with downstream passage. Structural and operational modifications such as installations of curtains, surface withdrawal, draw down, and selective withdrawal are often considered to alter the stratification and modify the currents to enhance the movement of fish toward the forebay where they may be collected effectively. Effectiveness of design modification in deep reservoirs is highly dependent on site-specific hydraulic and meteorological conditions, and numerical models are the tools of choice in design and selection of the optimum alternative. Although most hydropower reservoirs exhibit a vertical-longitudinal 2-D current structure, 3-D flow patterns are prevalent in reservoirs with multiple branches, and they occur near the power intakes as well. Simulation of these currents requires a 3-...