Spillway Control Structures: Difference between revisions
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“The value of an uncontrolled fixed crest spillway in providing an extremely reliable operation and a very low-cost maintenance facility is undeniable. Topographical, geological, economical, and political considerations at many dam sites may restrict the use of an uncontrolled fixed crest spillway. The solution to these problems is usually the inclusion of crest gates; however, the uncontrolled fixed crest spillway should be used regardless of these considerations when the time of concentration of the basin runoff into the reservoir is less than 12 hours. When the time of concentration is between 12 and 24 hours, an uncontrolled fixed crest spillway should be given preference over a gated spillway. Basically, the inclusion of crest gates allows the spillway crest to be placed significantly below the maximum operating reservoir level, in turn, permitting the entire reservoir to be used for normal operating purposes; and results in a much narrower spillway facility, avoiding the problems associated with high unit discharge/high-velocity flow and increased operation and maintenance costs. A gated spillway must include, as a minimum, two or preferably three spillway gates in order to satisfy safety concerns” <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 value of an uncontrolled fixed crest spillway in providing an extremely reliable [[operation]] and a very low-cost maintenance facility is undeniable. Topographical, geological, economical, and political considerations at many dam sites may restrict the use of an uncontrolled fixed crest spillway. The solution to these problems is usually the inclusion of crest gates; however, the uncontrolled fixed crest spillway should be used regardless of these considerations when the time of concentration of the basin runoff into the reservoir is less than 12 hours. When the time of concentration is between 12 and 24 hours, an uncontrolled fixed crest spillway should be given preference over a gated spillway. Basically, the inclusion of crest gates allows the spillway crest to be placed significantly below the maximum operating [[Reservoir Level|reservoir level]], in turn, [[permitting]] the entire reservoir to be used for normal operating purposes; and results in a much narrower spillway facility, avoiding the problems associated with high unit discharge/high-velocity flow and increased operation and maintenance costs. A gated spillway must include, as a minimum, two or preferably three spillway gates in order to satisfy safety concerns” <ref name="EM110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) | EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref> | ||
==Types of Control Structures== | ==Types of Control Structures== | ||
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* [[Fuseplug Spillways]] | * [[Fuseplug Spillways]] | ||
* [[Fusegate Spillways]] | * [[Fusegate Spillways]] | ||
* [[Gates|Gated Spillways]] | * [[Gates | Gated Spillways]] | ||
==Best Practices Resources== | ==Best Practices Resources== | ||
{{Document Icon}} [[ | {{Document Icon}} [[National Engineering Handbook: Chapter 50 - Earth Spillway Design | National Engineering Handbook: Chapter 50 - Earth Spillway Design (Natural Resources Conservation Service)]] | ||
{{Document Icon}} [[ | {{Document Icon}} [[National Engineering Handbook: Chapter 14 - Stage Discharge Relations | National Engineering Handbook: Chapter 14 - Stage Discharge Relations (Natural Resources Conservation Service)]] | ||
{{Document Icon}} [[Technical Release 210-39: Hydraulics of Broad-Crested Spillways|Technical Release 210-39: Hydraulics of Broad-Crested Spillways (Natural Resources Conservation Service)]] | {{Document Icon}} [[Technical Release 210-39: Hydraulics of Broad-Crested Spillways | Technical Release 210-39: Hydraulics of Broad-Crested Spillways (Natural Resources Conservation Service)]] | ||
{{Document Icon}} [[Measurement of Peak Discharge at Dams by Indirect Method|Measurement of Peak Discharge at Dams by Indirect Method (U.S. Geological Survey)]] | {{Document Icon}} [[Measurement of Peak Discharge at Dams by Indirect Method | Measurement of Peak Discharge at Dams by Indirect Method (U.S. Geological Survey)]] | ||
{{Document Icon}} [[Discharge Characteristics of Broad-Crested Weirs (GSC-397)|Discharge Characteristics of Broad-Crested Weirs (GSC-397) (U.S. Geological Survey)]] | {{Document Icon}} [[Discharge Characteristics of Broad-Crested Weirs (GSC-397) | Discharge Characteristics of Broad-Crested Weirs (GSC-397) (U.S. Geological Survey)]] | ||
{{Document Icon}} [[Hydraulic Design of Spillways (EM 1110-2-1603)|Hydraulic Design of Spillways (EM 1110-2-1603) (U.S. Army Corps of Engineers)]] | {{Document Icon}} [[Hydraulic Design of Spillways (EM 1110-2-1603) | Hydraulic Design of Spillways (EM 1110-2-1603) (U.S. Army Corps of Engineers)]] | ||
{{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) (Bureau of Reclamation)]] | {{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) (Bureau of Reclamation)]] | ||
{{Document Icon}} [[Design of Small Dams|Design of Small Dams (Bureau of Reclamation)]] | {{Document Icon}} [[Design of Small Dams | Design of Small Dams (Bureau of Reclamation)]] | ||
Revision as of 19:59, 21 October 2022
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| Labyrinth spillways are commonly installed to increase weir length and the associated discharge capacity. |
“The value of an uncontrolled fixed crest spillway in providing an extremely reliable operation and a very low-cost maintenance facility is undeniable. Topographical, geological, economical, and political considerations at many dam sites may restrict the use of an uncontrolled fixed crest spillway. The solution to these problems is usually the inclusion of crest gates; however, the uncontrolled fixed crest spillway should be used regardless of these considerations when the time of concentration of the basin runoff into the reservoir is less than 12 hours. When the time of concentration is between 12 and 24 hours, an uncontrolled fixed crest spillway should be given preference over a gated spillway. Basically, the inclusion of crest gates allows the spillway crest to be placed significantly below the maximum operating reservoir level, in turn, permitting the entire reservoir to be used for normal operating purposes; and results in a much narrower spillway facility, avoiding the problems associated with high unit discharge/high-velocity flow and increased operation and maintenance costs. A gated spillway must include, as a minimum, two or preferably three spillway gates in order to satisfy safety concerns” [1]
Types of Control Structures
- Broad-Crested Weirs
- Sharp-Crested Weirs
- Ogee-Crested Weirs
- Earth-Cut/Vegetated Spillways
- Labyrinth Spillways
- Piano Key Spillways
- Fuseplug Spillways
- Fusegate Spillways
- Gated Spillways
Best Practices Resources
Measurement of Peak Discharge at Dams by Indirect Method (U.S. Geological Survey)
Discharge Characteristics of Broad-Crested Weirs (GSC-397) (U.S. Geological Survey)
Hydraulic Design of Spillways (EM 1110-2-1603) (U.S. Army Corps of Engineers)
Design of Small Dams (Bureau of Reclamation)
Citations:
Revision ID: 4008
Revision Date: 10/21/2022