ASDSO Dam Safety Toolbox

Siphons: Difference between revisions

From ASDSO Dam Safety Toolbox
Jump to: navigation, search
No edit summary
No edit summary
 
(6 intermediate revisions by 2 users not shown)
Line 1: Line 1:
Many older dams were not constructed with a means of draining the reservoir. Lowering the reservoir may be needed for temporary construction, for emergency response, or when regular releases aren't needed. Siphons can be a low-cost means of providing a reservoir outlet if one does not exist. The key operational parameters are: (1) the required hydraulic lift cannot exceed the effective local atmospheric pressure adjusted for vapor pressure and frictional losses; (2) the discharge point of the siphon must be lower in elevation than the body of water to be siphoned; (3) the pipe or hose used for the siphon must be designed to operate at less than atmospheric pressures; (4) siphon outlets should only be used when there are no other feasible options; and (5) siphon outlets are difficult to prime.
<!-- Delete any sections that are not necessary to your topic. Add pictures/sections as needed -->
__NOTOC__
[[Category:Water Conveyance]]
----
<!-- Introductory paragraph or topic page summary -->
"Many older dams were not constructed with a means of draining the reservoir. Lowering the reservoir may be needed for temporary [[construction]], for [[Emergency Response|emergency response]], or when regular releases aren't needed. Siphons can be a low-cost means of providing a reservoir outlet if one does not exist. The key operational parameters are: (1) the required hydraulic lift cannot exceed the effective local atmospheric pressure adjusted for vapor pressure and frictional losses; (2) the discharge point of the siphon must be lower in elevation than the body of water to be siphoned; and (3) the pipe or hose used for the siphon must be designed to operate at less than atmospheric pressures. Note that siphon outlets can be difficult to prime."<ref name="DS-14">[[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, 2022]]</ref>


==Siphon Stories==
==Examples==
*[[Siphons when regular releases aren't needed]]
{{Website Icon}} [[Common Questions about Siphons | Get answers to some of the common questions about siphons]]
*[[Siphoning May Not Always Be Possible]]
*[[Low Pressure During Siphoning Can Collapse Pipe]]
*[[Pump... or Siphon?]]
*[[Siphons can pose Reservoir Level Control Challenges.]]


==Siphon as an Outlet Replacement==
==Trainings==
4 Key Questions that must have a Yes answer:
{{Video Icon}} [[On-Demand Webinar: Design of Siphon Systems]]


#Is the dam small enough and at a low enough elevation so that the use of a siphon is physically possible?
<!-- In the location of an in text citation, simply enclose the citation as follows: <ref> citation </ref>. Citations will automatically populate. Learn more at https://www.mediawiki.org/wiki/Help:Cite.  -->
#Will abandonment of the original outlet works not impact the reservoir's ability to pass the required inflow design storm (dictated by regulatory agencies)?
{{Citations}}
#Is there an alternate means to passively control reservoir level to prevent overfilling?
#Can the siphon reasonably be used for emergency drawdown if needed (in combination with pumps in some cases)?


References
<!-- Revision history information -->
*[https://3.238.206.13/images/f/f2/Simple_Steps_to_Siphoning.pdf Simple Steps to Siphoning]
{{revhistinf}}
*[https://3.238.206.13/images/d/d9/Guidelines_for_Use_of_Pumps_and_Siphons_for_Emergency_Reservoir_Drawdown.pdf Guidelines for Use of Pumps and Siphons for Emergency Reservoir Drawdown]
*[https://3.238.206.13/images/9/9c/Drawdown_System_Selection_Flow_Chart.pdf Drawdown System Selection Flow Chart]

Latest revision as of 00:38, 14 December 2022


"Many older dams were not constructed with a means of draining the reservoir. Lowering the reservoir may be needed for temporary construction, for emergency response, or when regular releases aren't needed. Siphons can be a low-cost means of providing a reservoir outlet if one does not exist. The key operational parameters are: (1) the required hydraulic lift cannot exceed the effective local atmospheric pressure adjusted for vapor pressure and frictional losses; (2) the discharge point of the siphon must be lower in elevation than the body of water to be siphoned; and (3) the pipe or hose used for the siphon must be designed to operate at less than atmospheric pressures. Note that siphon outlets can be difficult to prime."[1]

Examples

Get answers to some of the common questions about siphons

Trainings

On-Demand Webinar: Design of Siphon Systems


Citations:


Revision ID: 5540
Revision Date: 12/14/2022