Engineering Term Of The Month
Dams are made up of many components , including abutments , spillways , embankments , and other features . The spillway is the portion of the dam that provides a means of controlling the flow and providing conveyance from reservoir to tailwater for all flood discharges up to the spillway design flood .
Spillways can be classified as controlled spillways , whereas the flow is controlled by mechanical means such as gates , or uncontrolled spillways , whereas the flow is controlled by the geometry of the spillway only . Additionally , spillways may be primary or secondary . Primary are those designed to provide continuous or frequent regulated or unregulated releases from a reservoir , without significant damage to either the dam or its appurtenant structures . Secondary are those which are designed to be operated infrequently , possibly in anticipation of some degree of structural damage or erosion to the spillway that would occur during operation .
There are many types of spillways , including chutes , drop inlets , ogee crests , and siphons . The USBR Design Standards No . 14 provides a useful figure summarizing the many types of spillways .
The 2017 Oroville Dam disaster sheds important light on the potentially devastating effects of the massive volumes and flows of water that pass through a dam spillway , and the importance of the engineering design of spillways .
� FEMA , Federal Guidelines for Dam Safety , Glossary of Terms , April 2004
� U . S . Army Corps of Engineers , Hydraulic Design of Spillways , EM 1110-2-1603 16 January 1990
� USBR , Design Standards No . 14 Appurtenant Structures for Dams ( Spillways and Outlet Works ) Design Standard , February 2022
� https :// en . wikipedia . org / wiki / Oroville _ Dam _ crisis