ASDSO Dam Safety Toolbox

Spillway Terminal Structure Hydraulics: Difference between revisions

From ASDSO Dam Safety Toolbox
Jump to: navigation, search
No edit summary
No edit summary
Line 4: Line 4:
----
----
<!-- Introductory paragraph or topic page summary -->
<!-- Introductory paragraph or topic page summary -->
“The design of the energy dissipator probably includes more options than any other phase of spillway design. The selection of the type and design details of the dissipator is largely dependent upon the pertinent characteristics of the site, the magnitude of energy to be dissipated, and to a lesser extent upon the duration and frequency of spillway use. Good judgement is imperative to assure that all requirements of the particular project are met. Regardless of the type of dissipator selected, any spillway energy dissipator must operate safety at high discharges for extended periods of time without having to be shut down for emergency repairs. An emergency shutdown of the spillway facility during a large flood could cause overtopping of the dam and/or create unacceptable upstream flooding.” <ref name="EM110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) | EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>
“The design of the energy dissipator probably includes more options than any other phase of spillway design. The selection of the type and design details of the dissipator is largely dependent upon the pertinent characteristics of the site, the magnitude of energy to be dissipated, and to a lesser extent upon the duration and frequency of spillway use. Good judgement is imperative to assure that all requirements of the particular project are met. Regardless of the type of dissipator selected, any spillway energy dissipator must operate safety at high discharges for extended periods of time without having to be shut down for emergency repairs. An emergency shutdown of the spillway facility during a large flood could cause overtopping of the dam and/or create unacceptable upstream flooding.” <ref name="EM110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) | Hydraulic Design of Spillways (EM 1110-2-1603), USACE, 1992]]</ref>


“Except in some unusual conditions, an exit channel is required to transition between the stilling basin and the main channel of the river. Since dissipation of the entire spillway discharge energy within the stilling basin is not normally accomplished, enlarging the channel width immediately downstream from the (stilling) basin will assist in dissipating the residual energy. Due to the erosive nature of the highly turbulent flow exiting from a stilling basin, protection of the exit channel bed and side slopes is usually required to prevent channel scour and potential undermining of the stilling basin.” <ref name="EM110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) | EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>
“Except in some unusual conditions, an exit channel is required to transition between the stilling basin and the main channel of the river. Since dissipation of the entire spillway discharge energy within the stilling basin is not normally accomplished, enlarging the channel width immediately downstream from the (stilling) basin will assist in dissipating the residual energy. Due to the erosive nature of the highly turbulent flow exiting from a stilling basin, protection of the exit channel bed and side slopes is usually required to prevent channel scour and potential undermining of the stilling basin.” <ref name="EM110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) | EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>

Revision as of 20:53, 19 December 2022


“The design of the energy dissipator probably includes more options than any other phase of spillway design. The selection of the type and design details of the dissipator is largely dependent upon the pertinent characteristics of the site, the magnitude of energy to be dissipated, and to a lesser extent upon the duration and frequency of spillway use. Good judgement is imperative to assure that all requirements of the particular project are met. Regardless of the type of dissipator selected, any spillway energy dissipator must operate safety at high discharges for extended periods of time without having to be shut down for emergency repairs. An emergency shutdown of the spillway facility during a large flood could cause overtopping of the dam and/or create unacceptable upstream flooding.” [1]

“Except in some unusual conditions, an exit channel is required to transition between the stilling basin and the main channel of the river. Since dissipation of the entire spillway discharge energy within the stilling basin is not normally accomplished, enlarging the channel width immediately downstream from the (stilling) basin will assist in dissipating the residual energy. Due to the erosive nature of the highly turbulent flow exiting from a stilling basin, protection of the exit channel bed and side slopes is usually required to prevent channel scour and potential undermining of the stilling basin.” [1]

Learn more about this topic here: Energy Dissipation

Best Practices Resources

Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations), USBR, 2022

Hydraulic Design of Spillways (EM 1110-2-1603), USACE, 1992

Design of Small Dams, USBR, 1987


Citations:

  1. 1.0 1.1 Hydraulic Design of Spillways (EM 1110-2-1603), USACE, 1992 Cite error: Invalid <ref> tag; name "EM110-2-1603" defined multiple times with different content


Revision ID: 6025
Revision Date: 12/19/2022