Noun
A sluiceway or passage for superfluous water in a reservoir, to prevent too great pressure on the dam.
Source: Webster's dictionaryAn adequately designed spillway is critical to pond management. The purpose of the spillway is to carry surplus water from the pond, away from the face of the dam. It may consist of a mechanical control, such as an exit pipe installed in the base of the dam where it will empty below the dam site. Ken Kern
“An additional spillway was a long-drawn demand for enhancing the water discharge capacity of the dam during high flood. Source: Internet
A fuse plug spillway is a low embankment designed to be overtopped and washed away in the event of a large flood. Source: Internet
An auxiliary spillway releases flow in excess of the capacity of the service spillway. Source: Internet
A temporary, bypass spillway is in use. Source: Internet
Releases are passed through the outlet works and power station whenever possible and water will only flow over the spillway if significant flood inflows enter from upstream when the storage is close to full. Source: Internet