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Title: Plunge basins

item Hunt, Sherry
item CROWDER, JIMMY - Schnabel Engineering
item VISSER, KARL - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 7/19/2010
Publication Date: 6/1/2010
Citation: Hunt, S.L., Crowder, J., Visser, K. 2010. Plunge basins. In: Benik, R., et al., editors. Outlet Works Energy Dissipators, Chapter 4, FEMA Technical Manual P-679. CDROM.

Interpretive Summary:

Technical Abstract: An outlet works is a combination of structures and equipment required for the safe operation and control of water released from a reservoir to serve various purposes like regulating stream flow and water quality; releasing floodwater; and/or providing irrigation, municipal, or industrial water. Outlet works may include an intake structure, conduit, control house-gates, regulating gate or valve, gate chamber, and/or an energy dissipation structure. An energy dissipation structure slows the velocity and dissipates the energy of the flow released from an outlet works. A plunge basin is a deep pool energy dissipater into which a free jet of water can fall. The natural shape of a plunge basin is elliptical with a greater length parallel to the jet flow. Riprap and/or concrete are common materials used to line a plunge basin, but the plunge basin may be unlined to allow the scour to result from the hydraulic action of a free falling jet. This chapter discusses the types of plunge basins, jet trajectory of the discharge jet into a plunge basin, a description of the scour process for plunge basins, plunge basin design, and the use of slide gates with plunge basins.