|usage = spillway|
|Specific waterway usage allowing the controlled release of water from a waterbody (reservoir, canal, river)|
|Used on these elements|
|Tools for this tag|
An artificial structure channeling water which allows it release from a water body, either under controlled circumstances or as a means of ensuring that water levels do not overtop and destroy containing structures (dams, levees). Spillways will normally be free of water but remains dangerous since it can be expected at any time.
Spillways may be in regular use or designed only to be used in emergencies.
How to Map
As any waterway, spillways should connect to the water body which it drains and to the downstream outlet.
Wikipedia mentions different types of spillways, use spillway:type=* to describe these.
- waterway=dam - Spillways will most usually be mapped in association with dams
- natural=water + water=reservoir - Water area impounded behind.
- power=generator + generator:source=hydro - A spillway is often associated with hydropower power plants.
- emergency=siren + siren:purpose=flood – a siren that warns a downstream area of an impending discharge