Stilling Well Examples

The advantages of a vertical stilling well include:

Minimal requirement for water levels within the downstream channel.
Adaptable to sites with limited space due to other infrastructure restrictions.
Inclusion of a sleeve valve may allow for more economy of savings than other alternatives.

The disadvantages of the vertical stilling well include:

Requires a steel liner to reduce the potential for damage to the pedestal and lower portion of the chamber. In some cases, the anchorage for the steel liner has been determined to be underdesigned for the conditions actually experienced.
Problems have been experienced with the valve operating mechanism due to turbulence in the stilling well.
The typical valve and stilling well application is not well suited for use with high debris loads.

Typical Bureau of Reclamation stilling well application.
This stilling well was installed in 1966 and consists of a 10-foot wide well, 16-foot depth, and a 24-inch diameter sleeve valve. Design discharge is 78 cfs at a static head of 88 feet.
Stilling well at a conduit outlet.
This stilling basin was installed in a dam that operates under 600 feet of head. It was installed primarily to reduce noise impacts to nearby residences.
US Army Corps of Engineer's Stilling Well.

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: 4759
Revision Date: 12/02/2022