Definition of a Jurisdictional Dam

"Jurisdictional dam" is defined by statutes and rules as an artificial barrier for the impounding or diversion of water either 25 feet or more in height or having a storage capacity of more than 50 acre-feet.  Appurtenant works are included in jurisdiction.

A Jurisdictional Dam is NOT:

• Any barrier for the purpose of storing liquid-borne material (e.g. mine tailings dams)
• Any barrier that is a “release-contained barrier”
• Any barrier that is federally owned and operated
• Sole use transportation structures

"Height" means the vertical distance from the lowest elevation of the outside limit of the barrier at its intersection with the natural ground surface to the spillway crest elevation. For the purpose of determining jurisdictional status, the lowest elevation of the outside limit of the barrier may be the outlet pipe invert elevation if the outlet is constructed below natural ground.

"Storage capacity" means the maximum volume of water, sediment, or debris that can be impounded in the reservoir with no discharge of water, including the situation where an uncontrolled outlet becomes plugged. The storage capacity is reached when the water level is at the crest of the emergency spillway, or at the top of permanently mounted emergency spillway gates in the closed position. Storage capacity excludes dead storage below the natural ground surface.

"Release-contained barrier" means any artificial barrier and appurtenant works that comply with both of the following:

a) Has storage capacity that in the event of failure would be contained within property that the release-contained barrier owner owns, controls, operates, maintains or manages.

b) The property on which the release would be contained is not open to the public.