Uncontrolled Spillways - Revision history

Mpollei@gfnet.com at 19:20, 11 July 2023

2023-07-11T19:20:14Z

← Older revision		Revision as of 19:20, 11 July 2023
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	<noautolinks>==Best Practices Resources==</noautolinks>		<noautolinks>==Best Practices Resources==</noautolinks>
	{{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}} [[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]]
	{{Document Icon}} [[National Engineering Handbook: Chapter 50 - Earth Spillway Design \| National Engineering Handbook: Chapter 50 - Earth Spillway Design, NRCS~~, 2014~~]]		{{Document Icon}} [[National Engineering Handbook: Chapter 50 - Earth Spillway Design \| National Engineering Handbook: Chapter 50 - Earth Spillway Design, NRCS]]
	{{Document Icon}} [[Hydraulic Design of Spillways (EM 1110-2-1603) \| Hydraulic Design of Spillways (EM 1110-2-1603), USACE~~, 1992~~]]		{{Document Icon}} [[Hydraulic Design of Spillways (EM 1110-2-1603) \| Hydraulic Design of Spillways (EM 1110-2-1603), USACE]]

	==Trainings==		==Trainings==

Rmanwaring at 00:04, 14 December 2022

2022-12-14T00:04:03Z

← Older revision		Revision as of 00:04, 14 December 2022
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	“A controlled crest is one that includes gates which are used to control the flow; the uncontrolled crest is one unencumbered by gates”.<ref name="EM 1110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) \| EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>		“A controlled crest is one that includes gates which are used to control the flow; the uncontrolled crest is one unencumbered by gates”.<ref name="EM 1110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) \| EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>

	“Common to all uncontrolled [[spillways]] that are not integral with a concrete dam (i.e., located away from the dam on or through abutments, or on or through reservoir rim) is that existing topography must provide adequate space without excessive excavation. Also, the existing topography must allow appropriate orientation (alignment of the spillway between the reservoir and downstream river or stream) of the conveyance feature and terminal structure. Additionally, economics will come into play for all uncontrolled spillways”.<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, ~~2014~~]]</ref>		“Common to all uncontrolled [[spillways]] that are not integral with a concrete dam (i.e., located away from the dam on or through abutments, or on or through reservoir rim) is that existing topography must provide adequate space without excessive excavation. Also, the existing topography must allow appropriate orientation (alignment of the spillway between the reservoir and downstream river or stream) of the conveyance feature and terminal structure. Additionally, economics will come into play for all uncontrolled spillways”.<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>

	==Types of Uncontrolled Spillways==		==Types of Uncontrolled Spillways==

Rmanwaring: /* Trainings */

2022-12-13T23:42:03Z

Trainings

← Older revision		Revision as of 23:42, 13 December 2022
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	==Trainings==		==Trainings==
	{{Video Icon}}[[On-Demand Webinar: Introduction to Earth Spillway Design and Evaluation]]		{{Video Icon}} [[On-Demand Webinar: Introduction to Earth Spillway Design and Evaluation]]
	{{Video Icon}}[[On-Demand Webinar: Dam Safety with 3D Weirs]]		{{Video Icon}} [[On-Demand Webinar: Dam Safety with 3D Weirs]]
	{{Video Icon}}[[On-Demand Webinar: Hydraulic Design of Labyrinth Weirs]]		{{Video Icon}} [[On-Demand Webinar: Hydraulic Design of Labyrinth Weirs]]

Rmanwaring: /* Best Practices Resources */

2022-12-13T23:41:41Z

Best Practices Resources

← Older revision		Revision as of 23:41, 13 December 2022
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	*[[Free Overfall Spillways]]		*[[Free Overfall Spillways]]

	==Best Practices Resources==		<noautolinks>==Best Practices Resources==</noautolinks>
	~~{{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), USBR, 2022]]
	{{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}} [[National Engineering Handbook: Chapter 50 - Earth Spillway Design \| National Engineering Handbook: Chapter 50 - Earth Spillway Design, NRCS, 2014]]
	{{Document Icon}}[[National Engineering Handbook: Chapter 50 - Earth Spillway Design \| National Engineering Handbook: Chapter 50 - Earth Spillway Design (~~Natural Resources Conservation Service~~)]]		{{Document Icon}} [[Hydraulic Design of Spillways (EM 1110-2-1603) \| Hydraulic Design of Spillways (EM 1110-2-1603), USACE, 1992]]

	==Trainings==		==Trainings==
	{{Video Icon}}[[On-Demand Webinar: Introduction to Earth Spillway Design and Evaluation]]		{{Video Icon}}[[On-Demand Webinar: Introduction to Earth Spillway Design and Evaluation]]

Grichards at 22:57, 2 December 2022

2022-12-02T22:57:36Z

← Older revision		Revision as of 22:57, 2 December 2022
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	==Types of Uncontrolled Spillways==		==Types of Uncontrolled Spillways==
	*[[Chute ~~Spillways \| Chute (Open Channel or Trough)~~ Spillways]]		*[[Chute Spillways]]
	*[[Drop Spillways \| Drop Inlet Spillways]]		*[[Drop Spillways \| Drop Inlet Spillways]]
	*[[~~Side-Channel Spillways \| Double Side-Channel (Bathtub) and~~ Side-Channel Spillways]]		*[[Side-Channel Spillways]]
	*[[Free Overfall Spillways ~~\| Free Overfall Spillway including Ogee Crest, Various Shaped Weirs, and Straight Drop Control Structures~~]]		*[[Free Overfall Spillways]]

	==Best Practices Resources==		==Best Practices Resources==

Grichards at 06:11, 18 November 2022

2022-11-18T06:11:37Z

← Older revision		Revision as of 06:11, 18 November 2022
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	__NOTOC__		__NOTOC__
			[[Category:Spillways]]
	----		----
	<!-- Delete any sections that are not necessary to your topic. Add pictures/sections as needed -->		<!-- Delete any sections that are not necessary to your topic. Add pictures/sections as needed -->

Rmanwaring at 20:04, 21 October 2022

2022-10-21T20:04:25Z

← Older revision		Revision as of 20:04, 21 October 2022
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	“A controlled crest is one that includes gates which are used to control the flow; the uncontrolled crest is one unencumbered by gates”.<ref name="EM 1110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) \| EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>		“A controlled crest is one that includes gates which are used to control the flow; the uncontrolled crest is one unencumbered by gates”.<ref name="EM 1110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) \| EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>

	“Common to all uncontrolled spillways that are not integral with a concrete dam (i.e., located away from the dam on or through abutments, or on or through reservoir rim) is that existing topography must provide adequate space without excessive excavation. Also, the existing topography must allow appropriate orientation (alignment of the spillway between the reservoir and downstream river or stream) of the conveyance feature and terminal structure. Additionally, economics will come into play for all uncontrolled spillways”.<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, 2014]]</ref>		“Common to all uncontrolled [[spillways]] that are not integral with a concrete dam (i.e., located away from the dam on or through abutments, or on or through reservoir rim) is that existing topography must provide adequate space without excessive excavation. Also, the existing topography must allow appropriate orientation (alignment of the spillway between the reservoir and downstream river or stream) of the conveyance feature and terminal structure. Additionally, economics will come into play for all uncontrolled spillways”.<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, 2014]]</ref>

	==Types of Uncontrolled Spillways==		==Types of Uncontrolled Spillways==
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	==Best Practices Resources==		==Best Practices Resources==
	{{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}}[[~~Dams~~ National Engineering Handbook: Chapter 50- Earth Spillway Design\|~~Dams~~ National Engineering Handbook: Chapter 50- Earth Spillway Design (Natural Resources Conservation Service)]]		{{Document Icon}}[[National Engineering Handbook: Chapter 50 - Earth Spillway Design \| National Engineering Handbook: Chapter 50 - Earth Spillway Design (Natural Resources Conservation Service)]]
	==Trainings==		==Trainings==
	{{Video Icon}}[[On-Demand Webinar: Introduction to Earth Spillway Design and Evaluation]]		{{Video Icon}}[[On-Demand Webinar: Introduction to Earth Spillway Design and Evaluation]]

Rmanwaring at 22:51, 30 September 2022

2022-09-30T22:51:49Z

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 ==Types of Uncontrolled Spillways==
-'''"Chute (open channel or trough) spillways -''' include baffled apron, grade control sill, stepped chute, and various shaped weirs:<ref name="DS14" />
+*[[Chute Spillways | Chute (Open Channel or Trough) Spillways]]
-*"''Baffled apron spillway -'' This type of structure is suited for service, auxiliary, and emergency spillways.  Baffled apron spillways provide crest control, conveyance, and energy dissipation in one structure.  Primary considerations are associated with low to moderate hydraulic heads to ensure the baffles function properly and crest lengths are limited (i.e., significant cost increases as crest length increases).  Additionally, this spillway may be practical in areas where there is limited space for a terminal structure such as a hydraulic jump stilling basin.  Also, effectiveness (energy dissipation and discharge capacity) of baffled apron spillways can be adversely impacted by debris.  An example of a baffled apron spillway is the service spillway at Reclamation’s Conconully Dam (embankment).<ref name="DS14" />
+*[[Drop Spillways | Drop Inlet Spillways]]
-*''"Grade control sill spillway -'' This type of control structure is primarily suited for auxiliary and emergency spillways; however, in some cases, it can function as a service spillway.  A grade control sill is a less robust, minimal spillway typically limited to a vertical reinforced concrete wall (sill) that is placed in a trench through an excavated trapezoidal channel.  The grade control sill can be constructed in both rock and soil foundations.  The grade control sill spillway tends to have limited reserve discharge capacity, given channel armorment could be damaged or fail due to discharges that exceed design levels.  Therefore, an important consideration is to limit potential erosion during spillway operation.  In summary, this type of spillway should only be used on low head situations where the hydraulic drop (vertical dimension between the reservoir water surface and the downstream river or stream) can be effectively controlled, including limiting erosion potential.  Examples of grade control sill spillways include the service spillway at Reclamation’s Crane Prairie Dam (embankment) and the emergency spillway at Reclamation’s Davis Creek Dam (embankment).<ref name="DS14" />
+*[[Side-Channel Spillways | Double Side-Channel (Bathtub) and Side-Channel Spillways]]
-*''"Stepped chute spillway -'' This type of structure is suited for service and auxiliary spillways.  Stepped spillways refer to the stepped chute portion of the spillway and have primarily been used with RCC dams, which take advantage of the RCC lift construction methods, resulting in offsets on the downstream dam face, creating the spillway steps.  These steps can be formed or unformed RCC or capped with conventional concrete.  A chute-type crest (flat), along with straight or curved ogee crests, are typically used in combination with stepped chutes.  Other applications have involved incorporating both smooth flow surfaces and steps into a reinforced concrete spillway chute and RCC overtopping protection for an earth dam.  A consideration for a stepped spillway involves the potential kinetic energy dissipation via the steps, which can reduce the size and type of the terminal structure.  However, the kinetic energy dissipation potential may be reduced as flow depth (relative to the step size) increases (due to skimming flows).  Also, consideration should be given to evaluating the cavitation potential.  Examples of stepped spillways include the service spillway at Maricopa Water District’s Camp Dyer Diversion Dam (concrete), the auxiliary spillway (Joint Federal Project) at Reclamation’s Folsom Dam (composite), and the service spillway at Reclamation’s Upper Stillwater Dam (concrete). <ref name="DS14" />
+*[[Free Overfall Spillways | Free Overfall Spillway including Ogee Crest, Various Shaped Weirs, and Straight Drop Control Structures]]
 ==Best Practices Resources==

Cort at 15:05, 16 September 2022

2022-09-16T15:05:06Z

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 ----
 <!-- Delete any sections that are not necessary to your topic. Add pictures/sections as needed -->
 “A controlled crest is one that includes gates which are used to control the flow; the uncontrolled crest is one unencumbered by gates”.<ref name="EM 1110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) | EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>

Grichards at 04:43, 16 September 2022

2022-09-16T04:43:51Z

← Older revision		Revision as of 04:43, 16 September 2022
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	“A controlled crest is one that includes gates which are used to control the flow; the uncontrolled crest is one unencumbered by gates”.<ref name="EM 1110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) \| EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>		“A controlled crest is one that includes gates which are used to control the flow; the uncontrolled crest is one unencumbered by gates”.<ref name="EM 1110-2-1603">[[Hydraulic Design of Spillways (EM 1110-2-1603) \| EM 1110-2-1603 Hydraulic Design of Spillways, USACE, 1992]]</ref>

	“Common to all uncontrolled spillways that are not integral with a concrete dam (i.e., located away from the dam on or through abutments, or on or through reservoir rim) is that existing topography must provide adequate space without excessive excavation. Also, the existing topography must allow appropriate orientation (alignment of the spillway between the reservoir and downstream river or stream) of the conveyance feature and terminal structure. Additionally, economics will come into play for all uncontrolled spillways”.<ref name="DS14">[[Design Standards No. 14: Appurtenant Structures for Dams (~~Spillways and Outlet Works~~) \| Design Standards No. 14: Appurtenant Structures for Dams (~~Spillways and Outlet Works~~), USBR, 2014]]</ref>		“Common to all uncontrolled spillways that are not integral with a concrete dam (i.e., located away from the dam on or through abutments, or on or through reservoir rim) is that existing topography must provide adequate space without excessive excavation. Also, the existing topography must allow appropriate orientation (alignment of the spillway between the reservoir and downstream river or stream) of the conveyance feature and terminal structure. Additionally, economics will come into play for all uncontrolled spillways”.<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, 2014]]</ref>

	==Types of Uncontrolled Spillways==		==Types of Uncontrolled Spillways==
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	''"Culvert spillways -'' These types of control structures are suited for service, auxiliary, and emergency spillways. The culvert spillways are most applicable as appurtenant structures for low head dams (i.e., hydraulic head is 25 feet or less). Although there is simplicity and economy of construction, there are some significant potential concerns that must be fully addressed. These concerns include: (1) under certain conditions, the culvert may operate as a siphon, which can lead to adverse hydraulics (sudden surges and stoppages of flow, outflow exceeds inflow if operation shifts from inlet control to exit control, and significant vibrations that could damage the culvert and its foundation); (2) culverts on steep slopes flowing full can lead to negative pressures along the boundaries of the culvert, resulting in potential cavitation issues; and (3) if there are cracks or joints in low pressure areas, there is a possibility of drawing in soils surrounding the culvert. A culvert spillway does not have sizable reserve discharge capacity (i.e., increased discharge due to elevated reservoir water surface). Also, a culvert spillway is more susceptible to debris blockage. Examples of culvert spillways include the service spillway at Reclamation’s Martinez Dam (embankment) and the emergency spillway at Reclamation’s Weber Basin Comber Dam (embankment)”.<ref name="DS14" />		''"Culvert spillways -'' These types of control structures are suited for service, auxiliary, and emergency spillways. The culvert spillways are most applicable as appurtenant structures for low head dams (i.e., hydraulic head is 25 feet or less). Although there is simplicity and economy of construction, there are some significant potential concerns that must be fully addressed. These concerns include: (1) under certain conditions, the culvert may operate as a siphon, which can lead to adverse hydraulics (sudden surges and stoppages of flow, outflow exceeds inflow if operation shifts from inlet control to exit control, and significant vibrations that could damage the culvert and its foundation); (2) culverts on steep slopes flowing full can lead to negative pressures along the boundaries of the culvert, resulting in potential cavitation issues; and (3) if there are cracks or joints in low pressure areas, there is a possibility of drawing in soils surrounding the culvert. A culvert spillway does not have sizable reserve discharge capacity (i.e., increased discharge due to elevated reservoir water surface). Also, a culvert spillway is more susceptible to debris blockage. Examples of culvert spillways include the service spillway at Reclamation’s Martinez Dam (embankment) and the emergency spillway at Reclamation’s Weber Basin Comber Dam (embankment)”.<ref name="DS14" />

	~~==Examples==~~
	~~{{Website Icon}}~~
	==Best Practices Resources==		==Best Practices Resources==
	{{Document Icon}}[[Hydraulic Design of Spillways (EM 1110-2-1603)]]		{{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 (~~Spillways and Outlet Works~~)]]		{{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}}[[Dams National Engineering Handbook: Chapter 50- Earth Spillway Design\|Dams National Engineering Handbook: Chapter 50- Earth Spillway Design (Natural Resources Conservation Service)]]
	==Trainings==		==Trainings==
	{{Video Icon}}		{{Video Icon}}[[On-Demand Webinar: Introduction to Earth Spillway Design and Evaluation]]
			{{Video Icon}}[[On-Demand Webinar: Dam Safety with 3D Weirs]]
			{{Video Icon}}[[On-Demand Webinar: Hydraulic Design of Labyrinth Weirs]]


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