|tunnel = flooded|
|A long (>100m) tunnel where flowing water or other fluid prevent humans from safely walking inside|
|Used on these elements|
|Tools for this tag|
A flooded tunnel is an artificial structure intended to channel water on a significant distance. Its dimensions and length allow human to fit inside but safe walking is impossible due to high amount of water or other fluid expected in operation.
Such tunnels are different from tunnel=culvert where human usually can't enter and for which dimensions are restricted to building or way it is supposed to go underpass.
They are also different from tunnel=yes where a path is usually intended for human to safely pass and where water level is usally controlled for safety reasons, like Canal Saint-Martin in Paris.
man_made=pipeline is actually different since a pipeline is built from tubes assemblies.
How to map
|Horizontal tunnels carrying water from intakes to penstocks. Such ways have a pipe flow regime, their inlet are always below the water level and no air can get inside.|
|A headrace tunnel works at atmospheric pressure and water have a free surface while flowing inside. Its inlet is designed to be always above water level and air can get inside too.|