Design and Construction of Outlet Works - Revision history

Grichards@gfnet.com at 22:31, 28 July 2023

2023-07-28T22:31:44Z

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	\| [[Image:1SE1.jpg\|350px\|x350px\|link=Rehab vs. Replacement]]		\| [[Image:1SE1.jpg\|350px\|x350px\|link=Rehab vs. Replacement]]
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	\|style="text-align:center; font-size:90%;"\| Learn more about the differences between [[Rehab vs. Replacement\|rehabilitation and replacement]] of outlet works.		\|style="text-align:center; font-size:90%;"\| Learn more about the differences between [[Rehab vs. Replacement\|rehabilitation and replacement]] of outlet works. (Image Source: [https://damoutletworks.org/Pages/RehabReplace/Rehab1.html DamOutletWorks.org])
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	“Proper pipeline installation involves much more than just covering up the pipe. A buried pipe is a structure that incorporates both the properties of the pipe and the properties of the soil surrounding the pipe. The structural design of a pipeline is based on certain soil conditions, and construction control is important to ensure these conditions are met”.<ref name="USBR Pipe Bedding">[[Pipe Bedding and Backfill \| Pipe Bedding and Backfill, USBR, 1996]]</ref>		“Proper pipeline installation involves much more than just covering up the pipe. A buried pipe is a structure that incorporates both the properties of the pipe and the properties of the soil surrounding the pipe. The structural design of a pipeline is based on certain soil conditions, and construction control is important to ensure these conditions are met”.<ref name="USBR Pipe Bedding">[[Pipe Bedding and Backfill \| Pipe Bedding and Backfill, USBR, 1996]]</ref>

	“The conduit-foundation contact must not be overlooked as a path for potential piping, particularly when the foundation is earth. Prevention of piping along the conduit consists of providing a smooth, firm contact surface free from loose or disintegrated materials and slush grouted to seal joints in rock foundations. If the foundation surface is subject to deterioration when exposed to the atmosphere, it may be necessary to protect the foundation surface with suitable earthfill, a concrete pad, or an acceptable sealing compound until conduit construction commences”.<ref name="ACER 9" />		“The conduit-foundation contact must not be overlooked as a path for potential piping, particularly when the foundation is earth. Prevention of piping along the conduit consists of providing a smooth, firm contact surface free from loose or disintegrated materials and slush grouted to seal joints in [[Rock Foundations\|rock foundations]]. If the foundation surface is subject to deterioration when exposed to the atmosphere, it may be necessary to protect the foundation surface with suitable earthfill, a concrete pad, or an acceptable sealing compound until conduit construction commences”.<ref name="ACER 9" />

	“Filters placed around conduits to prevent piping should encircle conduits on earth foundations. Filters around conduits on firm formation materials should extend only to the foundation surface if the formation has to be excavated by blasting or ripping. The filters should meet the same criteria for dry unit weight and filtering as for other filters within the embankment”.<ref name="ACER 9" />		“Filters placed around conduits to prevent piping should encircle conduits on earth foundations. Filters around conduits on firm formation materials should extend only to the foundation surface if the formation has to be excavated by blasting or ripping. The filters should meet the same criteria for dry unit weight and filtering as for other filters within the embankment”.<ref name="ACER 9" />

Mpollei@gfnet.com at 16:43, 11 July 2023

2023-07-11T16:43:15Z

Rmanwaring at 20:41, 20 December 2022

2022-12-20T20:41:48Z

← Older revision		Revision as of 20:41, 20 December 2022
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	<!-- 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 -->
	==Outlet Works Sizing and Capacity==		==Outlet Works Sizing and Capacity==
	“The sizing of the outlet works should take into account the possibility of using it to reduce the size or frequency of spillway discharges. The necessity of emergency drawdown capability and low flow discharge capability should be considered during the outlet works planning phase. The selection of type and arrangement of outlet works structures should be based upon consideration of the costs of [[operation]] and maintenance likely to be incurred during the project life. Reliability under emergency [[Flood Conditions\|flood conditions]] is a fundamental operational requirement of outlet works facilities”.<ref name="USACE [[Structural]] Design of [[Outlet Works]]">[[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| ~~EM 1110-2-2400~~ Structural Design and Evaluation of Outlet Works, USACE, 2003]]</ref>		“The sizing of the outlet works should take into account the possibility of using it to reduce the size or frequency of spillway discharges. The necessity of emergency drawdown capability and low flow discharge capability should be considered during the outlet works planning phase. The selection of type and arrangement of outlet works structures should be based upon consideration of the costs of [[operation]] and maintenance likely to be incurred during the project life. Reliability under emergency [[Flood Conditions\|flood conditions]] is a fundamental operational requirement of outlet works facilities”.<ref name="USACE [[Structural]] Design of [[Outlet Works]]">[[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400), USACE, 2003]]</ref>

	“Flows through river outlets and canal or pipeline outlets change throughout the year and may involve a wide range of discharge under varying heads. The accuracy and ease of control are major considerations, and a great amount of planning may be justified in determining the type of control devices that can be best utilized”.<ref name="USACE Hydrologic Requirements">[[Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420) \| EM 1110-2-1420 ~~Hydrologic Engineering Requirements for Reservoirs~~, USACE, 1997]]</ref>		“Flows through river outlets and canal or pipeline outlets change throughout the year and may involve a wide range of discharge under varying heads. The accuracy and ease of control are major considerations, and a great amount of planning may be justified in determining the type of control devices that can be best utilized”.<ref name="USACE Hydrologic Requirements">[[Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420) \| Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420), USACE, 1997]]</ref>

	“An outlet works may be used for diverting the river flow or portion thereof during a phase of the [[construction]] period, thus avoiding the necessity for supplementary installations for that purpose. The outlet structure size dictated by this use rather than the size indicated for ordinary outlet requirements may determine the final outlet works capacity”.<ref name="USACE Hydrologic Requirements" />		“An outlet works may be used for diverting the river flow or portion thereof during a phase of the [[construction]] period, thus avoiding the necessity for supplementary installations for that purpose. The outlet structure size dictated by this use rather than the size indicated for ordinary outlet requirements may determine the final outlet works capacity”.<ref name="USACE Hydrologic Requirements" />
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	“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of [[Pipe Installation\|pipe installation]] is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />		“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of [[Pipe Installation\|pipe installation]] is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />

	"The use of an externally shaped circular conduit through an embankment dam should be carefully evaluated due to concerns with the difficulty or inability to uniformly compact the earthfill around the conduit. Precast concrete pipe is the most often used externally shaped circular conduit. The earthfill beneath the haunches of the conduit cannot be adequately compacted with pneumatic tired equipment and requires compaction with hand held tampers. Efforts to obtain proper compaction using hand tampers could cause movement or displacement of smaller conduits. Improper compaction of the earthfill around the conduit and movement of the conduit can result in differential [[settlement]] and hydraulic fracture. The use of externally shaped circular conduits differs between the major dam building agencies. Reclamation does not use externally shaped circular conduits in their designs due to concerns about the inadequate compaction of earthfill against the conduit. NRCS allows use of externally shaped circular conduits, if they are constructed on cradles or bedding. The use of externally shaped circular conduits (e.g., precast concrete pipe) requires thorough inspection and strict adherence to proper construction techniques to achieve quality assurance of earthfill compaction."<ref name="FEMA 484">[[Technical Manual: Conduits through Embankment Dams (FEMA P-484)\|Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]</ref>		"The use of an externally shaped circular conduit through an embankment dam should be carefully evaluated due to concerns with the difficulty or inability to uniformly compact the earthfill around the conduit. Precast concrete pipe is the most often used externally shaped circular conduit. The earthfill beneath the haunches of the conduit cannot be adequately compacted with pneumatic tired equipment and requires compaction with hand held tampers. Efforts to obtain proper compaction using hand tampers could cause movement or displacement of smaller conduits. Improper compaction of the earthfill around the conduit and movement of the conduit can result in differential [[settlement]] and hydraulic fracture. The use of externally shaped circular conduits differs between the major dam building agencies. Reclamation does not use externally shaped circular conduits in their designs due to concerns about the inadequate compaction of earthfill against the conduit. NRCS allows use of externally shaped circular conduits, if they are constructed on cradles or bedding. The use of externally shaped circular conduits (e.g., precast concrete pipe) requires thorough inspection and strict adherence to proper construction techniques to achieve quality assurance of earthfill compaction."<ref name="FEMA 484">[[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]</ref>

	“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| TM MERL-2011-36 ~~Guidelines for Reporting Corroded Pipe~~, USBR, 2011]]</ref>		“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| Guidelines for Reporting Corroded Pipe (TM MERL-2011-36), USBR, 2011]]</ref>

	==Examples==		==Examples==
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	{{Website Icon}} [[Construction Considerations \| Learn more about pertinent construction considerations for outlet works]]		{{Website Icon}} [[Construction Considerations \| Learn more about pertinent construction considerations for outlet works]]
	{{Website Icon}} [https://damfailures.org/case-study/anita-dam-montana-1997/ Learn from mistakes made during the installation of an outlet conduit at Anita Dam (DamFailures.org)]		{{Website Icon}} [https://damfailures.org/case-study/anita-dam-montana-1997/ Learn from mistakes made during the installation of an outlet conduit at Anita Dam (DamFailures.org)]

	<noautolinks>==Best Practices Resources==</noautolinks>		<noautolinks>==Best Practices Resources==</noautolinks>
	{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR, 2022]]		{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR, 2022]]
	{{Document Icon}} [[~~Design of Small~~ Dams \| ~~Design of Small~~ Dams~~, USBR, 1987]]~~		{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]]
	~~{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) \| Hydraulic Design of Stilling Basins~~ and ~~Energy Dissipators (EM 25)~~, ~~USBR~~, ~~1984~~]]
	{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679) \| Technical Manual: Outlet Works Energy Dissipators (FEMA P-679), FEMA, 2010]]		{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679) \| Technical Manual: Outlet Works Energy Dissipators (FEMA P-679), FEMA, 2010]]
	{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675) \| Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675), FEMA, 2007]]		{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675) \| Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675), FEMA, 2007]]
			{{Document Icon}} [[National Engineering Handbook: Chapter 45 - Filter Diaphragms \| National Engineering Handbook: Chapter 45 - Filter Diaphragms, NRCS, 2007]]
	{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]		{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]
	~~{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]]~~		{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400), USACE, 2003]]
	~~{{Document Icon}} [[National Engineering Handbook: Chapter 45 - Filter Diaphragms \| National Engineering Handbook: Chapter 45 - Filter Diaphragms, NRCS, 2007]]~~		{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902) \| Conduits, Culverts, and Pipes (EM 1110-2-2902), USACE, 1998]]
	{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400), USACE, 2003]]		{{Document Icon}} [[Design of Small Dams \| Design of Small Dams, USBR, 1987]]
	{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902) \| Conduits, Culverts, and Pipes (EM 1110-2-2902), USACE, 1998]]		{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) \| Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25), USBR, 1984]]
	{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE, 1980]]		{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE, 1980]]

Rmanwaring: /* Best Practices Resources */

2022-12-13T21:52:07Z

Best Practices Resources

Grichards at 04:01, 2 December 2022

2022-12-02T04:01:56Z

← Older revision		Revision as of 04:01, 2 December 2022
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	“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of [[Pipe Installation\|pipe installation]] is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />		“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of [[Pipe Installation\|pipe installation]] is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />

			"The use of an externally shaped circular conduit through an embankment dam should be carefully evaluated due to concerns with the difficulty or inability to uniformly compact the earthfill around the conduit. Precast concrete pipe is the most often used externally shaped circular conduit. The earthfill beneath the haunches of the conduit cannot be adequately compacted with pneumatic tired equipment and requires compaction with hand held tampers. Efforts to obtain proper compaction using hand tampers could cause movement or displacement of smaller conduits. Improper compaction of the earthfill around the conduit and movement of the conduit can result in differential [[settlement]] and hydraulic fracture. The use of externally shaped circular conduits differs between the major dam building agencies. Reclamation does not use externally shaped circular conduits in their designs due to concerns about the inadequate compaction of earthfill against the conduit. NRCS allows use of externally shaped circular conduits, if they are constructed on cradles or bedding. The use of externally shaped circular conduits (e.g., precast concrete pipe) requires thorough inspection and strict adherence to proper construction techniques to achieve quality assurance of earthfill compaction."<ref name="FEMA 484">[[Technical Manual: Conduits through Embankment Dams (FEMA P-484)\|Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]</ref>

	“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| TM MERL-2011-36 Guidelines for Reporting Corroded Pipe, USBR, 2011]]</ref>		“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| TM MERL-2011-36 Guidelines for Reporting Corroded Pipe, USBR, 2011]]</ref>

Grichards at 03:47, 2 December 2022

2022-12-02T03:47:02Z

← Older revision		Revision as of 03:47, 2 December 2022
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	\| [[Image:1SE1.jpg\|350px\|x350px\|link=Rehab vs. Replacement]]		\| [[Image:1SE1.jpg\|350px\|x350px\|link=Rehab vs. Replacement]]
	\|-		\|-
	\|style="text-align:center; font-size:90%;"\| Learn more [[about]] the differences between [[Rehab vs. Replacement\|rehabilitation and replacement]] of outlet works.		\|style="text-align:center; font-size:90%;"\| Learn more about the differences between [[Rehab vs. Replacement\|rehabilitation and replacement]] of outlet works.
	\|}		\|}
	<!-- 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 -->

Grichards at 06:02, 18 November 2022

2022-11-18T06:02:00Z

← Older revision		Revision as of 06:02, 18 November 2022
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	__NOTOC__		__NOTOC__
	[[Category:~~Structural Design Considerations~~]]		[[Category:Outlet Works]]
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Grichards at 05:42, 18 November 2022

2022-11-18T05:42:08Z

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	__NOTOC__		__NOTOC__
			[[Category:Structural Design Considerations]]
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Rmanwaring at 20:07, 21 October 2022

2022-10-21T20:07:56Z

Grichards at 18:35, 27 September 2022

2022-09-27T18:35:21Z

← Older revision		Revision as of 18:35, 27 September 2022
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	==Examples==		==Examples==
	{{Website Icon}} ~~Learn more about~~ [[Rehab vs. Replacement]] of outlet works		{{Website Icon}} [[Rehab vs. Replacement\|Learn more about rehabilitation versus replacement of outlet works]]
	{{Website Icon}} ~~Learn more about~~ [[Filters and Drains]] for outlet works		{{Website Icon}} [[Filters and Drains\|Learn more about filters and drains for outlet works]]
	{{Website Icon}} ~~Learn more about~~ [[Accounting for Energy Dissipation]] at outlet works		{{Website Icon}} [[Accounting for Energy Dissipation\|Learn more about accounting for energy dissipation at outlet works]]
	{{Website Icon}} Learn more about pertinent ~~[[Construction Considerations]]~~ for outlet works		{{Website Icon}} [[Construction Considerations\|Learn more about pertinent construction considerations for outlet works]]
	{{Website Icon}} ~~Learn from mistakes made during the installation of an outlet conduit at~~ [https://damfailures.org/case-study/anita-dam-montana-1997/ Anita Dam (DamFailures.org)]		{{Website Icon}} [https://damfailures.org/case-study/anita-dam-montana-1997/ Learn from mistakes made during the installation of an outlet conduit at Anita Dam (DamFailures.org)]
	==Best Practices Resources==		==Best Practices Resources==
	{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations)\|Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) (Bureau of Reclamation)]]		{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations)\|Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) (Bureau of Reclamation)]]

← Older revision		Revision as of 20:41, 20 December 2022
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	<!-- 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 -->
	==Outlet Works Sizing and Capacity==		==Outlet Works Sizing and Capacity==
	“The sizing of the outlet works should take into account the possibility of using it to reduce the size or frequency of spillway discharges. The necessity of emergency drawdown capability and low flow discharge capability should be considered during the outlet works planning phase. The selection of type and arrangement of outlet works structures should be based upon consideration of the costs of [[operation]] and maintenance likely to be incurred during the project life. Reliability under emergency [[Flood Conditions\|flood conditions]] is a fundamental operational requirement of outlet works facilities”.<ref name="USACE [[Structural]] Design of [[Outlet Works]]">[[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| ~~EM 1110-2-2400~~ Structural Design and Evaluation of Outlet Works, USACE, 2003]]</ref>		“The sizing of the outlet works should take into account the possibility of using it to reduce the size or frequency of spillway discharges. The necessity of emergency drawdown capability and low flow discharge capability should be considered during the outlet works planning phase. The selection of type and arrangement of outlet works structures should be based upon consideration of the costs of [[operation]] and maintenance likely to be incurred during the project life. Reliability under emergency [[Flood Conditions\|flood conditions]] is a fundamental operational requirement of outlet works facilities”.<ref name="USACE [[Structural]] Design of [[Outlet Works]]">[[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400), USACE, 2003]]</ref>

	“Flows through river outlets and canal or pipeline outlets change throughout the year and may involve a wide range of discharge under varying heads. The accuracy and ease of control are major considerations, and a great amount of planning may be justified in determining the type of control devices that can be best utilized”.<ref name="USACE Hydrologic Requirements">[[Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420) \| EM 1110-2-1420 ~~Hydrologic Engineering Requirements for Reservoirs~~, USACE, 1997]]</ref>		“Flows through river outlets and canal or pipeline outlets change throughout the year and may involve a wide range of discharge under varying heads. The accuracy and ease of control are major considerations, and a great amount of planning may be justified in determining the type of control devices that can be best utilized”.<ref name="USACE Hydrologic Requirements">[[Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420) \| Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420), USACE, 1997]]</ref>

	“An outlet works may be used for diverting the river flow or portion thereof during a phase of the [[construction]] period, thus avoiding the necessity for supplementary installations for that purpose. The outlet structure size dictated by this use rather than the size indicated for ordinary outlet requirements may determine the final outlet works capacity”.<ref name="USACE Hydrologic Requirements" />		“An outlet works may be used for diverting the river flow or portion thereof during a phase of the [[construction]] period, thus avoiding the necessity for supplementary installations for that purpose. The outlet structure size dictated by this use rather than the size indicated for ordinary outlet requirements may determine the final outlet works capacity”.<ref name="USACE Hydrologic Requirements" />
Line 36:		Line 36:
	“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of [[Pipe Installation\|pipe installation]] is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />		“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of [[Pipe Installation\|pipe installation]] is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />

	"The use of an externally shaped circular conduit through an embankment dam should be carefully evaluated due to concerns with the difficulty or inability to uniformly compact the earthfill around the conduit. Precast concrete pipe is the most often used externally shaped circular conduit. The earthfill beneath the haunches of the conduit cannot be adequately compacted with pneumatic tired equipment and requires compaction with hand held tampers. Efforts to obtain proper compaction using hand tampers could cause movement or displacement of smaller conduits. Improper compaction of the earthfill around the conduit and movement of the conduit can result in differential [[settlement]] and hydraulic fracture. The use of externally shaped circular conduits differs between the major dam building agencies. Reclamation does not use externally shaped circular conduits in their designs due to concerns about the inadequate compaction of earthfill against the conduit. NRCS allows use of externally shaped circular conduits, if they are constructed on cradles or bedding. The use of externally shaped circular conduits (e.g., precast concrete pipe) requires thorough inspection and strict adherence to proper construction techniques to achieve quality assurance of earthfill compaction."<ref name="FEMA 484">[[Technical Manual: Conduits through Embankment Dams (FEMA P-484)\|Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]</ref>		"The use of an externally shaped circular conduit through an embankment dam should be carefully evaluated due to concerns with the difficulty or inability to uniformly compact the earthfill around the conduit. Precast concrete pipe is the most often used externally shaped circular conduit. The earthfill beneath the haunches of the conduit cannot be adequately compacted with pneumatic tired equipment and requires compaction with hand held tampers. Efforts to obtain proper compaction using hand tampers could cause movement or displacement of smaller conduits. Improper compaction of the earthfill around the conduit and movement of the conduit can result in differential [[settlement]] and hydraulic fracture. The use of externally shaped circular conduits differs between the major dam building agencies. Reclamation does not use externally shaped circular conduits in their designs due to concerns about the inadequate compaction of earthfill against the conduit. NRCS allows use of externally shaped circular conduits, if they are constructed on cradles or bedding. The use of externally shaped circular conduits (e.g., precast concrete pipe) requires thorough inspection and strict adherence to proper construction techniques to achieve quality assurance of earthfill compaction."<ref name="FEMA 484">[[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]</ref>

	“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| TM MERL-2011-36 ~~Guidelines for Reporting Corroded Pipe~~, USBR, 2011]]</ref>		“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| Guidelines for Reporting Corroded Pipe (TM MERL-2011-36), USBR, 2011]]</ref>

	==Examples==		==Examples==
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	{{Website Icon}} [[Construction Considerations \| Learn more about pertinent construction considerations for outlet works]]		{{Website Icon}} [[Construction Considerations \| Learn more about pertinent construction considerations for outlet works]]
	{{Website Icon}} [https://damfailures.org/case-study/anita-dam-montana-1997/ Learn from mistakes made during the installation of an outlet conduit at Anita Dam (DamFailures.org)]		{{Website Icon}} [https://damfailures.org/case-study/anita-dam-montana-1997/ Learn from mistakes made during the installation of an outlet conduit at Anita Dam (DamFailures.org)]

	<noautolinks>==Best Practices Resources==</noautolinks>		<noautolinks>==Best Practices Resources==</noautolinks>
	{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR, 2022]]		{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR, 2022]]
	{{Document Icon}} [[~~Design of Small~~ Dams \| ~~Design of Small~~ Dams~~, USBR, 1987]]~~		{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]]
	~~{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) \| Hydraulic Design of Stilling Basins~~ and ~~Energy Dissipators (EM 25)~~, ~~USBR~~, ~~1984~~]]
	{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679) \| Technical Manual: Outlet Works Energy Dissipators (FEMA P-679), FEMA, 2010]]		{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679) \| Technical Manual: Outlet Works Energy Dissipators (FEMA P-679), FEMA, 2010]]
	{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675) \| Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675), FEMA, 2007]]		{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675) \| Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675), FEMA, 2007]]
			{{Document Icon}} [[National Engineering Handbook: Chapter 45 - Filter Diaphragms \| National Engineering Handbook: Chapter 45 - Filter Diaphragms, NRCS, 2007]]
	{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]		{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]
	~~{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]]~~		{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400), USACE, 2003]]
	~~{{Document Icon}} [[National Engineering Handbook: Chapter 45 - Filter Diaphragms \| National Engineering Handbook: Chapter 45 - Filter Diaphragms, NRCS, 2007]]~~		{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902) \| Conduits, Culverts, and Pipes (EM 1110-2-2902), USACE, 1998]]
	{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400), USACE, 2003]]		{{Document Icon}} [[Design of Small Dams \| Design of Small Dams, USBR, 1987]]
	{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902) \| Conduits, Culverts, and Pipes (EM 1110-2-2902), USACE, 1998]]		{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) \| Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25), USBR, 1984]]
	{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE, 1980]]		{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE, 1980]]

← Older revision		Revision as of 04:01, 2 December 2022
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	“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of [[Pipe Installation\|pipe installation]] is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />		“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of [[Pipe Installation\|pipe installation]] is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />

			"The use of an externally shaped circular conduit through an embankment dam should be carefully evaluated due to concerns with the difficulty or inability to uniformly compact the earthfill around the conduit. Precast concrete pipe is the most often used externally shaped circular conduit. The earthfill beneath the haunches of the conduit cannot be adequately compacted with pneumatic tired equipment and requires compaction with hand held tampers. Efforts to obtain proper compaction using hand tampers could cause movement or displacement of smaller conduits. Improper compaction of the earthfill around the conduit and movement of the conduit can result in differential [[settlement]] and hydraulic fracture. The use of externally shaped circular conduits differs between the major dam building agencies. Reclamation does not use externally shaped circular conduits in their designs due to concerns about the inadequate compaction of earthfill against the conduit. NRCS allows use of externally shaped circular conduits, if they are constructed on cradles or bedding. The use of externally shaped circular conduits (e.g., precast concrete pipe) requires thorough inspection and strict adherence to proper construction techniques to achieve quality assurance of earthfill compaction."<ref name="FEMA 484">[[Technical Manual: Conduits through Embankment Dams (FEMA P-484)\|Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]</ref>

	“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| TM MERL-2011-36 Guidelines for Reporting Corroded Pipe, USBR, 2011]]</ref>		“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| TM MERL-2011-36 Guidelines for Reporting Corroded Pipe, USBR, 2011]]</ref>

← Older revision		Revision as of 16:43, 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. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR~~, 2022~~]]		{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR]]
	{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS~~, 2019~~]]		{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS]]
	{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679) \| Technical Manual: Outlet Works Energy Dissipators (FEMA P-679), FEMA~~, 2010~~]]		{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679) \| Technical Manual: Outlet Works Energy Dissipators (FEMA P-679), FEMA]]
	{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675) \| Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675), FEMA~~, 2007~~]]		{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675) \| Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675), FEMA]]
	{{Document Icon}} [[National Engineering Handbook: Chapter 45 - Filter Diaphragms \| National Engineering Handbook: Chapter 45 - Filter Diaphragms, NRCS~~, 2007~~]]		{{Document Icon}} [[National Engineering Handbook: Chapter 45 - Filter Diaphragms \| National Engineering Handbook: Chapter 45 - Filter Diaphragms, NRCS]]
	{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA~~, 2005~~]]		{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA]]
	{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400), USACE~~, 2003~~]]		{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400), USACE]]
	{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902) \| Conduits, Culverts, and Pipes (EM 1110-2-2902), USACE~~, 1998~~]]		{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902) \| Conduits, Culverts, and Pipes (EM 1110-2-2902), USACE]]
	{{Document Icon}} [[Design of Small Dams \| Design of Small Dams, USBR~~, 1987~~]]		{{Document Icon}} [[Design of Small Dams \| Design of Small Dams, USBR]]
	{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) \| Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25), USBR~~, 1984~~]]		{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) \| Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25), USBR]]
	{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE~~, 1980~~]]		{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE]]

	==Trainings==		==Trainings==

← Older revision		Revision as of 21:52, 13 December 2022
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	==Energy Dissipation==		==Energy Dissipation==
	“The two types of energy dissipating devices most commonly used in conjunction with outlet works on concrete dams are hydraulic jump stilling basins and plunge pools. On some dams, it is possible to arrange the outlet works in conjunction with the spillway to utilize the spillway-stilling device for dissipating the energy of the water discharging from the river outlets. Energy-dissipating devices for free-flow conduit outlet works are essentially the same as those for spillways”.<ref name="USACE Hydrologic Requirements" />		“The two types of energy dissipating devices most commonly used in conjunction with outlet works on concrete dams are hydraulic jump [[Stilling Basins\|stilling basins]] and [[Plunge Pools\|plunge pools]]. On some dams, it is possible to arrange the outlet works in conjunction with the spillway to utilize the spillway-stilling device for dissipating the energy of the water discharging from the river outlets. Energy-dissipating devices for free-flow conduit outlet works are essentially the same as those for spillways”.<ref name="USACE Hydrologic Requirements" />

	==Outlet Works Conduit Design Considerations==		==Outlet Works Conduit Design Considerations==
Line 46:		Line 46:
	{{Website Icon}} [[Construction Considerations \| Learn more about pertinent construction considerations for outlet works]]		{{Website Icon}} [[Construction Considerations \| Learn more about pertinent construction considerations for outlet works]]
	{{Website Icon}} [https://damfailures.org/case-study/anita-dam-montana-1997/ Learn from mistakes made during the installation of an outlet conduit at Anita Dam (DamFailures.org)]		{{Website Icon}} [https://damfailures.org/case-study/anita-dam-montana-1997/ Learn from mistakes made during the installation of an outlet conduit at Anita Dam (DamFailures.org)]
	==Best Practices Resources==		<noautolinks>==Best Practices Resources==</noautolinks>
	{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) ~~(Bureau of Reclamation)~~]]		{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR, 2022]]
	{{Document Icon}} [[Design of Small Dams \| Design of Small Dams ~~(Bureau of Reclamation)~~]]		{{Document Icon}} [[Design of Small Dams \| Design of Small Dams, USBR, 1987]]
	{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) \| Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) ~~(Bureau of Reclamation)~~]]		{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) \| Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25), USBR, 1984]]
	{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679) \| Technical Manual: Outlet Works Energy Dissipators (~~Federal Emergency Management Agency~~)]]		{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679) \| Technical Manual: Outlet Works Energy Dissipators (FEMA P-679), FEMA, 2010]]
	{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675) \| Technical Manual: Plastic Pipe Used in Embankment Dams (~~Federal Emergency Management Agency~~)]]		{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675) \| Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675), FEMA, 2007]]
	{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (~~Federal Emergency Management Agency~~)]]		{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (FEMA P-484), FEMA, 2005]]
	{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs ~~(Natural Resources Conservation Service)~~]]		{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]]
	{{Document Icon}} [[National Engineering Handbook: Chapter 45 - Filter Diaphragms \| National Engineering Handbook: Chapter 45 - Filter Diaphragms ~~(Natural Resources Conservation Service)~~]]		{{Document Icon}} [[National Engineering Handbook: Chapter 45 - Filter Diaphragms \| National Engineering Handbook: Chapter 45 - Filter Diaphragms, NRCS, 2007]]
	{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) ~~(U.S. Army Corps of Engineers)~~]]		{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400), USACE, 2003]]
	{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902) \| Conduits, Culverts, and Pipes (EM 1110-2-2902) ~~(U.S. Army Corps of Engineers)~~]]		{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902) \| Conduits, Culverts, and Pipes (EM 1110-2-2902), USACE, 1998]]
	{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) ~~(U.S. Army Corps of Engineers)~~]]		{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE, 1980]]

	==Trainings==		==Trainings==
	{{Video Icon}} [[On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures]]		{{Video Icon}} [[On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures]]

← Older revision		Revision as of 20:07, 21 October 2022
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	\| [[Image:1SE1.jpg\|350px\|x350px\|link=Rehab vs. Replacement]]		\| [[Image:1SE1.jpg\|350px\|x350px\|link=Rehab vs. Replacement]]
	\|-		\|-
	\|style="text-align:center; font-size:90%;"\| Learn more about the differences between [[Rehab vs. Replacement\|rehabilitation and replacement]] of outlet works.		\|style="text-align:center; font-size:90%;"\| Learn more [[about]] the differences between [[Rehab vs. Replacement\|rehabilitation and replacement]] of outlet works.
	\|}		\|}
	<!-- 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 -->
	==Outlet Works Sizing and Capacity==		==Outlet Works Sizing and Capacity==
	“The sizing of the outlet works should take into account the possibility of using it to reduce the size or frequency of spillway discharges. The necessity of emergency drawdown capability and low flow discharge capability should be considered during the outlet works planning phase. The selection of type and arrangement of outlet works structures should be based upon consideration of the costs of operation and maintenance likely to be incurred during the project life. Reliability under emergency flood conditions is a fundamental operational requirement of outlet works facilities”.<ref name="USACE Structural Design of Outlet Works">[[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| EM 1110-2-2400 Structural Design and Evaluation of Outlet Works, USACE, 2003]]</ref>		“The sizing of the outlet works should take into account the possibility of using it to reduce the size or frequency of spillway discharges. The necessity of emergency drawdown capability and low flow discharge capability should be considered during the outlet works planning phase. The selection of type and arrangement of outlet works structures should be based upon consideration of the costs of [[operation]] and maintenance likely to be incurred during the project life. Reliability under emergency [[Flood Conditions\|flood conditions]] is a fundamental operational requirement of outlet works facilities”.<ref name="USACE [[Structural]] Design of [[Outlet Works]]">[[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| EM 1110-2-2400 Structural Design and Evaluation of Outlet Works, USACE, 2003]]</ref>

	“Flows through river outlets and canal or pipeline outlets change throughout the year and may involve a wide range of discharge under varying heads. The accuracy and ease of control are major considerations, and a great amount of planning may be justified in determining the type of control devices that can be best utilized”.<ref name="USACE Hydrologic Requirements">[[Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420) \| EM 1110-2-1420 Hydrologic Engineering Requirements for Reservoirs, USACE, 1997]]</ref>		“Flows through river outlets and canal or pipeline outlets change throughout the year and may involve a wide range of discharge under varying heads. The accuracy and ease of control are major considerations, and a great amount of planning may be justified in determining the type of control devices that can be best utilized”.<ref name="USACE Hydrologic Requirements">[[Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420) \| EM 1110-2-1420 Hydrologic Engineering Requirements for Reservoirs, USACE, 1997]]</ref>

	“An outlet works may be used for diverting the river flow or portion thereof during a phase of the construction period, thus avoiding the necessity for supplementary installations for that purpose. The outlet structure size dictated by this use rather than the size indicated for ordinary outlet requirements may determine the final outlet works capacity”.<ref name="USACE Hydrologic Requirements" />		“An outlet works may be used for diverting the river flow or portion thereof during a phase of the [[construction]] period, thus avoiding the necessity for supplementary installations for that purpose. The outlet structure size dictated by this use rather than the size indicated for ordinary outlet requirements may determine the final outlet works capacity”.<ref name="USACE Hydrologic Requirements" />

	==Elevation of Outlet Works Inlet(s) / Outlet(s)==		==Elevation of Outlet Works Inlet(s) / Outlet(s)==
	“The establishment of the intake level is influenced by several considerations such as maintaining the required discharge at the minimum reservoir operating elevation, establishing a silt retention space, and allowing selective withdrawal to achieve suitable water temperature and/or quality. Dams which will impound water for irrigation, domestic use, or other conservation purposes must have the outlet works intake low enough to be able to draw the water down to the bottom of the allocated storage space. Further, if the outlets are to be used to evacuate the reservoir for inspection or repair of the dam, they should be placed as low as practicable. However, it is usual practice to make an allowance in a reservoir for inactive storage for silt deposition, fish and wildlife conservation, and recreation”.<ref name="USACE Hydrologic Requirements" />		“The establishment of the intake level is influenced by several considerations such as maintaining the required discharge at the minimum reservoir operating elevation, establishing a silt retention space, and allowing selective withdrawal to achieve suitable water temperature and/or quality. Dams which will impound water for [[irrigation]], domestic use, or other conservation purposes must have the outlet works intake low enough to be able to draw the water down to the bottom of the allocated storage space. Further, if the outlets are to be used to evacuate the reservoir for inspection or repair of the dam, they should be placed as low as practicable. However, it is usual practice to make an allowance in a reservoir for inactive storage for silt deposition, fish and wildlife conservation, and recreation”.<ref name="USACE Hydrologic Requirements" />

	~~“Reservoirs~~ become thermally stratified, and taste and odor vary between elevation. Therefore, the outlet intake should be established at the best elevation to achieve satisfactory water quality for the purpose intended. Downstream fish and wildlife requirements may determine the temperature at which the outlet releases should be made. Municipal and industrial water use increases the emphasis on water quality and requires the water to be drawn from the reservoir at the elevation which produces the most satisfactory combination of odor, taste, and temperature. Water supply releases can be made through separate outlet works at different elevations if requirements for the individual water uses are not the same and the reservoir is stratified”.<ref name="USACE Hydrologic Requirements" />		“[[Reservoirs]] become thermally stratified, and taste and odor vary between elevation. Therefore, the outlet intake should be established at the best elevation to achieve satisfactory water quality for the purpose intended. Downstream fish and wildlife requirements may determine the temperature at which the outlet releases should be made. Municipal and industrial water use increases the emphasis on water quality and requires the water to be drawn from the reservoir at the elevation which produces the most satisfactory combination of odor, taste, and temperature. Water supply releases can be made through separate outlet works at different elevations if requirements for the individual water uses are not the same and the reservoir is stratified”.<ref name="USACE Hydrologic Requirements" />

	==Energy Dissipation==		==Energy Dissipation==
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	“Care should be exercised by the construction staff to ensure that backfill material quality, lift thickness, placement moisture content, and dry unit weight requirements are complied with and that hand-operated compactors are of the minimum mass. Special care should be exercised to ensure that within the impervious zone, no continuous layers or pervious material occur along the conduit. Controlling lift thickness and moisture content is important because the earthfill in the bottom of the lift must be forced laterally against the conduit during the compaction process. The entire construction process along the conduit must be carefully observed and inspected. An area of great concern is compaction of earthfill at the contact between earthfill compacted by special methods along the conduit and earthfill compacted by regular tamping rollers. The compaction of material by special methods along the conduit must extend a sufficient distance from the conduit to be overlapped by the compactive effort specified for rollers in the regular compaction zone”.<ref name="ACER 9" />		“Care should be exercised by the construction staff to ensure that backfill material quality, lift thickness, placement moisture content, and dry unit weight requirements are complied with and that hand-operated compactors are of the minimum mass. Special care should be exercised to ensure that within the impervious zone, no continuous layers or pervious material occur along the conduit. Controlling lift thickness and moisture content is important because the earthfill in the bottom of the lift must be forced laterally against the conduit during the compaction process. The entire construction process along the conduit must be carefully observed and inspected. An area of great concern is compaction of earthfill at the contact between earthfill compacted by special methods along the conduit and earthfill compacted by regular tamping rollers. The compaction of material by special methods along the conduit must extend a sufficient distance from the conduit to be overlapped by the compactive effort specified for rollers in the regular compaction zone”.<ref name="ACER 9" />

	“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of pipe installation is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />		“There are two basic types of pipe, rigid and flexible. Rigid pipe must be supported on the bottom portion of the pipe. Flexible pipe must be supported on both the bottom and on the sides of the pipe. Proper soil support of the pipe is critical to the performance of both types of pipe, and proper inspection of [[Pipe Installation\|pipe installation]] is essential in obtaining the required support. Inspection for proper soil support involves checking the: (1) adequacy of soil in trench walls and foundation; (2) type of soil used for bedding, embedment, and backfill; (3) distribution of soil around pipe; (4) density of soil around pipe; (5) deflection of flexible pipe”.<ref name="USBR Pipe Bedding" />

	“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| TM MERL-2011-36 Guidelines for Reporting Corroded Pipe, USBR, 2011]]</ref>		“There are numerous reasons why a pipe may develop leaks, including improper foundation or embedment, overpressure and transients, poor jointing, inadequate restraint or blocking, and corrosion”.<ref name="TM MERL-2011-36">[[Guidelines for Reporting Corroded Pipe (TM MERL-2011-36) \| TM MERL-2011-36 Guidelines for Reporting Corroded Pipe, USBR, 2011]]</ref>

	==Examples==		==Examples==
	{{Website Icon}} [[Rehab vs. Replacement\|Learn more about rehabilitation versus replacement of outlet works]]		{{Website Icon}} [[Rehab vs. Replacement \| Learn more about rehabilitation versus replacement of outlet works]]
	{{Website Icon}} [[Filters and Drains\|Learn more about filters and drains for outlet works]]		{{Website Icon}} [[Filters and Drains \| Learn more about filters and drains for outlet works]]
	{{Website Icon}} [[Accounting for Energy Dissipation\|Learn more about accounting for energy dissipation at outlet works]]		{{Website Icon}} [[Accounting for Energy Dissipation \| Learn more about accounting for energy dissipation at outlet works]]
	{{Website Icon}} [[Construction Considerations\|Learn more about pertinent construction considerations for outlet works]]		{{Website Icon}} [[Construction Considerations \| Learn more about pertinent construction considerations for outlet works]]
	{{Website Icon}} [https://damfailures.org/case-study/anita-dam-montana-1997/ Learn from mistakes made during the installation of an outlet conduit at Anita Dam (DamFailures.org)]		{{Website Icon}} [https://damfailures.org/case-study/anita-dam-montana-1997/ Learn from mistakes made during the installation of an outlet conduit at Anita Dam (DamFailures.org)]
	==Best Practices Resources==		==Best Practices Resources==
	{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations)\|Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) (Bureau of Reclamation)]]		{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works 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)]]
	{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25)\|Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) (Bureau of Reclamation)]]		{{Document Icon}} [[Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) \| Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25) (Bureau of Reclamation)]]
	{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679)\|Technical Manual: Outlet Works Energy Dissipators (Federal Emergency Management Agency)]]		{{Document Icon}} [[Technical Manual: Outlet Works Energy Dissipators (FEMA P-679) \| Technical Manual: Outlet Works Energy Dissipators (Federal Emergency Management Agency)]]
	{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675)\|Technical Manual: Plastic Pipe Used in Embankment Dams (Federal Emergency Management Agency)]]		{{Document Icon}} [[Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675) \| Technical Manual: Plastic Pipe Used in Embankment Dams (Federal Emergency Management Agency)]]
	{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484)\|Technical Manual: Conduits through Embankment Dams (Federal Emergency Management Agency)]]		{{Document Icon}} [[Technical Manual: Conduits through Embankment Dams (FEMA P-484) \| Technical Manual: Conduits through Embankment Dams (Federal Emergency Management Agency)]]
	{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs\|Technical Release 210-60: Earth Dams and Reservoirs (Natural Resources Conservation Service)]]		{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs (Natural Resources Conservation Service)]]
	{{Document Icon}} [[~~Dams~~ National Engineering Handbook: Chapter 45- Filter Diaphragms\|National Engineering Handbook: Chapter 45- Filter Diaphragms (Natural Resources Conservation Service)]]		{{Document Icon}} [[National Engineering Handbook: Chapter 45 - Filter Diaphragms \| National Engineering Handbook: Chapter 45 - Filter Diaphragms (Natural Resources Conservation Service)]]
	{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400)\|Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) (U.S. Army Corps of Engineers)]]		{{Document Icon}} [[Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) \| Structural Design and Evaluation of Outlet Works (EM 1110-2-2400) (U.S. Army Corps of Engineers)]]
	{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902)\|Conduits, Culverts, and Pipes (EM 1110-2-2902) (U.S. Army Corps of Engineers)]]		{{Document Icon}} [[Conduits, Culverts, and Pipes (EM 1110-2-2902) \| Conduits, Culverts, and Pipes (EM 1110-2-2902) (U.S. Army Corps of Engineers)]]
	{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602)\|Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) (U.S. Army Corps of Engineers)]]		{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) (U.S. Army Corps of Engineers)]]
	==Trainings==		==Trainings==
	{{Video Icon}} [[On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures]]		{{Video Icon}} [[On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures]]
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	{{Video Icon}} [[On-Demand Webinar: Hydraulics 101: Intro to Hydraulics for Dam Safety]]		{{Video Icon}} [[On-Demand Webinar: Hydraulics 101: Intro to Hydraulics for Dam Safety]]
	{{Video Icon}} [[On-Demand Webinar: Hydraulics 201 for Dam Safety]]		{{Video Icon}} [[On-Demand Webinar: Hydraulics 201 for Dam Safety]]


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