Hydraulics

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Analysis of spillway hydraulics using Computational Fluid Dynamics (CFD).

The hydraulic design of a dam includes a knowledge of the following foundational topics: pressurized and free-surface flow, uniform flow, gradually and rapidly varied flow, steady and unsteady flow, energy and momentum principles, energy losses, and cavitation.

Types of Evaluations

• Hydraulic Performance of Spillways
• Hydraulic Performance of Outlet Works
• Dam Breach Inundation Analysis
• Spillway Integrity Analysis
• Erosion & Scour Mitigation
• Tailwater Modeling

Types of Hydraulic Modeling

Selection of either a one-, two-, or three-dimensional hydraulic model is necessary depending on both the complexity of the flow conditions and the level of accuracy required of the model. Hydraulic modeling helps to attain a higher-optimized level of operation of the dam and reduce uncertainty.

“Maintaining the high efficiency of a spillway requires careful design of the spillway crest, the approach configuration, and the piers and abutments. For this reason, when design considerations require departure from established design data, model studies (or three-dimensional computer models) of the spillway system should be accomplished”. Physical model studies or three-dimensional Computational Fluid Dynamics (CFD) models are recommended to confirm any design that involves complex geometric considerations and/or large discharges and velocities.

• One-Dimensional Hydraulic Models
• Two-Dimensional Hydraulic Models
• Three-Dimensional Hydraulic Models

Best Practices Resources

Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures (FEMA P-946) (Federal Emergency Management Agency)

Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94) (Federal Emergency Management Agency)

Technical Release 210-60: Earth Dams and Reservoirs (Natural Resources Conservation Service)

Hydraulic Design of Spillways (EM 1110-2-1603) (U.S. Army Corps of Engineers)

Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) (U.S. Army Corps of Engineers)

Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations) (Bureau of Reclamation)

Design of Small Dams (Bureau of Reclamation)

Trainings

On-Demand Webinar: Hydraulics 101: Intro to Hydraulics for Dam Safety

On-Demand Webinar: Hydraulics 201 for Dam Safety

On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures

On-Demand Webinar: Designing Spillways to Mitigate Failure Modes

On-Demand Webinar: Introduction to Addressing Inadequate Conveyance Capacity at Dams

Citations:

Revision ID: 5429
Revision Date: 12/13/2022