Siphons can pose Reservoir Level Control Challenges.

Message: Considering a siphon as a replacement to a low level outlet? There may still be a need to passively control reservoir level.

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  This small urban reservoir in Yellowstone County has a deteriorated outlet works. Used primarily for recreation and lawn irrigation, there is no need to make releases.

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  Abandonment of the outlet works and replacement with a siphon is a reasonable alternative to consider. However...

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  The reservoir level is passively controlled with a drop inlet. Abandonment of the conduit also results in elimination of the drop inlet. Although offstream, the potential for over filling form the nearby canal remains. In addition to the installation of the siphon, other means must be considered to control the reservoir level.

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  Lowering the auxiliary spillway is not practical. Other options must be considered which could include adding a high level overflow pipe for reservoir control. The siphon could then be available for emergency drawdown.

Note: The content on this page was originally created as part of DamOutletWorks.org (DOWL, 2018). It has subsequently been updated and reformatted as part of the Dam Safety Toolbox.
Revision ID: 3202
Revision Date: 09/15/2022