Auxiliary Spillways: Difference between revisions
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“An auxiliary spillway is infrequently used and may be a secondary spillway (augmenting a service spillway discharge capacity). During [[operation]] there could be some degree of [[structural]] damage or erosion to the auxiliary spillway due to releases up to and including the maximum design discharge. Auxiliary [[spillways]] may be less robust, erosion-resistant structures consisting of some cast-in-place [[Reinforced Concrete|reinforced concrete]], [[riprap]] channel protection and/or unarmored excavated channels”.<ref name="DS14">[[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations) | Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations), USBR, 2022]]</ref> | “An auxiliary spillway is infrequently used and may be a secondary spillway (augmenting a service spillway discharge capacity). During [[operation]] there could be some degree of [[structural]] damage or erosion to the auxiliary spillway due to releases up to and including the maximum design discharge. Auxiliary [[spillways]] may be less robust, erosion-resistant structures consisting of some cast-in-place [[Reinforced Concrete | reinforced concrete]], [[riprap]] channel protection and/or unarmored excavated channels”.<ref name="DS14">[[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations) | Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations), USBR, 2022]]</ref> | ||
In the past, auxiliary spillways were commonly referred to as "[[Emergency Spillways|emergency spillways]]". This practice should be discontinued. Media references to flow through “emergency spillways” often leads to a misconception by the public that an emergency condition exists at a dam when the dam is safely functioning as designed. <ref name="FEMA94">[[Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94)| Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94), FEMA, 2013]]</ref> | In the past, auxiliary spillways were commonly referred to as "[[Emergency Spillways | emergency spillways]]". This practice should be discontinued. Media references to flow through “emergency spillways” often leads to a misconception by the public that an emergency condition exists at a dam when the dam is safely functioning as designed. <ref name="FEMA94">[[Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94)| Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94), FEMA, 2013]]</ref> | ||
==Life Cycle of Auxiliary Spillways== | ==Life Cycle of Auxiliary Spillways== | ||
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==Examples== | ==Examples== | ||
{{Website Icon}} [https://damfailures.org/lessons-learned/high-and-significant-hazard-dams-should-be-design-to-pass-an-appropriate-design-flood-dams-constructed-prior-to-the-availability-of-extreme-rainfall-data-should-be-assessed-to-make-sure-they-have-ad/ Learn more about the importance of spillway design criteria at DamFailures.org] | {{Website Icon}} [https://damfailures.org/lessons-learned/high-and-significant-hazard-dams-should-be-design-to-pass-an-appropriate-design-flood-dams-constructed-prior-to-the-availability-of-extreme-rainfall-data-should-be-assessed-to-make-sure-they-have-ad/ Learn more about the importance of spillway design criteria at DamFailures.org] | ||
==Best Practices Resources== | |||
{{Document Icon}} [[ | <noautolinks>==Best Practices Resources==</noautolinks> | ||
{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs | Technical Release 210-60: Earth Dams and Reservoirs | {{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations) | Design Standards No. 14: Appurtenant Structures for Dams (Ch. 3: General Spillway Design Considerations), USBR, 2022]] | ||
{{Document Icon}} [[National Engineering Handbook: Chapter 21 - Design Hydrographs | National Engineering Handbook: Chapter 21 - Design Hydrographs | {{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs | Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]] | ||
{{Document Icon}} [[ | {{Document Icon}} [[National Engineering Handbook: Chapter 21 - Design Hydrographs | National Engineering Handbook: Chapter 21 - Design Hydrographs, NRCS, 2019]] | ||
{{Document Icon}} [[ | {{Document Icon}} [[Engineering Guidelines for the Evaluation of Hydropower Projects: Chapter 2- Selecting and Accommodating Inflow Design Floods for Dams | Engineering Guidelines for the Evaluation of Hydropower Projects: Chapter 2- Selecting and Accommodating Inflow Design Floods for Dams, FERC, 2015]] | ||
{{Document Icon}} [[Design | {{Document Icon}} [[National Engineering Handbook: Chapter 50 - Earth Spillway Design | National Engineering Handbook: Chapter 50 - Earth Spillway Design, NRCS, 2014]] | ||
{{Document Icon}} [[Design of | {{Document Icon}} [[Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94) | Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94), FEMA, 2013]] | ||
{{Document Icon}} [[ | {{Document Icon}} [[Hydraulic Design of Spillways (EM 1110-2-1603) | Hydraulic Design of Spillways (EM 1110-2-1603), USACE, 1992]] | ||
{{Document Icon}} [[Design of Small Dams | Design of Small Dams, USBR, 1987]] | |||
==Trainings== | ==Trainings== | ||
{{Video Icon}}[[On-Demand Webinar: Introduction to Addressing Inadequate Conveyance Capacity at Dams]] | {{Video Icon}}[[On-Demand Webinar: Introduction to Addressing Inadequate Conveyance Capacity at Dams]] | ||
Revision as of 00:09, 14 December 2022
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| Learn more about the importance of spillway design criteria at DamFailures.org |
“An auxiliary spillway is infrequently used and may be a secondary spillway (augmenting a service spillway discharge capacity). During operation there could be some degree of structural damage or erosion to the auxiliary spillway due to releases up to and including the maximum design discharge. Auxiliary spillways may be less robust, erosion-resistant structures consisting of some cast-in-place reinforced concrete, riprap channel protection and/or unarmored excavated channels”.[1]
In the past, auxiliary spillways were commonly referred to as " emergency spillways". This practice should be discontinued. Media references to flow through “emergency spillways” often leads to a misconception by the public that an emergency condition exists at a dam when the dam is safely functioning as designed. [2]
Life Cycle of Auxiliary Spillways
Examples
Learn more about the importance of spillway design criteria at DamFailures.org
Best Practices Resources
Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019
National Engineering Handbook: Chapter 21 - Design Hydrographs, NRCS, 2019
National Engineering Handbook: Chapter 50 - Earth Spillway Design, NRCS, 2014
Selecting and Accommodating Inflow Design Floods for Dams (FEMA P-94), FEMA, 2013
Hydraulic Design of Spillways (EM 1110-2-1603), USACE, 1992
Design of Small Dams, USBR, 1987
Trainings
On-Demand Webinar: Introduction to Addressing Inadequate Conveyance Capacity at Dams
On-Demand Webinar: Inspection and Assessment of Spillways
On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures
Citations:
Revision ID: 5524
Revision Date: 12/14/2022