|waterway = brook|
|Tiny waterway, often, but not always, dry part of the year.|
|Used on these elements|
|Tools for this tag|
|Usage of this tag is disputed. You can join the discussion.|
A brook is a tiny linear depression in the ground that carries water for at least some part of the year, although it may contain little water or even be dry for most of the year. Use intermittent=yes accordingly. It is always possible to jump or even step over a brook. Brooks are usually very shallow, say, 10–50 cm deep and are likely always less than 1 m deep. Brooks can vary from 10 cm to 1 m wide.
So far there are no exact criteria for deciding whether a feature is a stream or a brook. To instigate some discussion, there's a gallery of various very narrow waterways.