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Hydraulic Performance of Outlet Works: Difference between revisions

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[[Category:Hydraulics]]
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==Outlet Works Hydraulics==
“The hydraulic analysis of the flow through a flood control conduit or sluice usually involves consideration of two conditions of low. When the upper pool is at low stages, for example during diversion, open-channel flow may occur in the conduit. As the [[Reservoir Level|reservoir level]] is raised, the depth of flow in the conduit increases until the conduit flows full. In the design of [[Outlet Works|outlet works]], the number and size of the conduits and the elevations of their grade line are determined with consideration of overall costs. The conduits are usually designed to provide the required discharge capacity at a specified reservoir operating level, although adequate capacity during diversion may govern in some cases. Conduits should normally slope downstream to ensure drainage. The elevation of good foundation materials may govern the invert elevation of conduits for an embankment dam.” <ref name ="EM1110-2-1602">[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) | EM 1110-2-1602 Hydraulic Design of Reservoir Outlet Works, USACE, 1980]]</ref>
“The hydraulic analysis of the flow through a flood control conduit or sluice usually involves consideration of two conditions of low. When the upper pool is at low stages, for example during diversion, open-channel flow may occur in the conduit. As the reservoir level is raised, the depth of flow in the conduit increases until the conduit flows full. In the design of outlet works, the number and size of the conduits and the elevations of their grade line are determined with consideration of overall costs. The conduits are usually designed to provide the required discharge capacity at a specified reservoir operating level, although adequate capacity during diversion may govern in some cases. Conduits should normally slope downstream to ensure drainage. The elevation of good foundation materials may govern the invert elevation of conduits for an embankment dam.” <ref name ="EM1110-2-1602">[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) | EM 1110-2-1602 Hydraulic Design of Reservoir Outlet Works, USACE, 1980]]</ref>


==Reservoir Drawdown==
See also: [[Hydrology]] > [[Normal Flow Conditions]] > [[Reservoir Drawdown]]
“Where practicable, reservoir release facilities should be provided to lower the pool to a safe level adequate to correct conditions that might threaten the integrity f the dam.” <ref name ="FEMA93">[[Federal Guidelines for Dam Safety (FEMA P-93) | FEMA 93 Federal Guidelines for Dam Safety, FEMA, 2004 ]]</ref>  


“Low level outlets are provided to maintain downstream flows for all levels of the reservoirs operational pool. The outlets may also serve to empty the reservoir to permit inspection, to make needed repairs, or to maintain the upstream face of the dam or other structures normally inundated.” <ref name ="EM-1110-2-1420">[[Hydrologic Engineering Requirements for Reservoirs (EM 1110-2-1420)| EM 1110-2-1420 Hydrologic Engineering Requirements for Reservoirs, USACE, 1997 ]]</ref>
==Best Practices Resources==
{{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]]
{{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]]
{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) | Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE]]


==Examples==
{{Website Icon}}
==Best Practices Resources==
{{Document Icon}}
==Trainings==
==Trainings==
{{Video Icon}}
{{Video Icon}} [[On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures]]
{{Video Icon}} [[On-Demand Webinar: Terminal Structures and Energy Dissipation at Outlet Works and Spillways]]


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Latest revision as of 19:05, 11 July 2023


“The hydraulic analysis of the flow through a flood control conduit or sluice usually involves consideration of two conditions of low. When the upper pool is at low stages, for example during diversion, open-channel flow may occur in the conduit. As the reservoir level is raised, the depth of flow in the conduit increases until the conduit flows full. In the design of outlet works, the number and size of the conduits and the elevations of their grade line are determined with consideration of overall costs. The conduits are usually designed to provide the required discharge capacity at a specified reservoir operating level, although adequate capacity during diversion may govern in some cases. Conduits should normally slope downstream to ensure drainage. The elevation of good foundation materials may govern the invert elevation of conduits for an embankment dam.” [1]

See also: Hydrology > Normal Flow Conditions > Reservoir Drawdown

Best Practices Resources

Technical Manual: Outlet Works Energy Dissipators (FEMA P-679), FEMA

Technical Manual: Plastic Pipe Used in Embankment Dams (FEMA P-675), FEMA

Design of Small Dams, USBR

Hydraulic Design of Stilling Basins and Energy Dissipators (EM 25), USBR

Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE

Trainings

On-Demand Webinar: Inlet and Outlet Hydraulics for Spillways and Outlet Structures

On-Demand Webinar: Terminal Structures and Energy Dissipation at Outlet Works and Spillways


Citations:


Revision ID: 7123
Revision Date: 07/11/2023