|Indicates that waterway or water body does not permanently contain water|
|Used on these elements|
|Tools for this tag|
The intermittent=* key is used to indicate that a waterway or body of water does not permanently contain water.
intermittent=yes is used
- to indicate that a waterway=* (river, stream, etc.) does not have a permanent flow
- to indicate that a water=* body is not permanently filled with water
If this tag does not appear on a water-based object, the assumed default is intermittent=no.
Intermittent vs. seasonal
For waterbodies that contain water and dry up on a seasonal basis there is also seasonal=* to more specifically indicate this. intermittent=yes is widely used for waterbodies with seasonal variation as well - either with or without a supplemental seasonal=yes. Some mappers also prefer to use intermittent=yes only for non-seasonal intermittency, but generally intermittent=yes is used for any waterways and waterbodies without permanent water presence, including seasonal and ephemeral water presence.
The typical case of adding intermittent=yes is that mapper encounters a waterbody/waterway in a dry state but with indications of recent water cover or water flow. In some cases it is possible to get further info about water presence, for example whatever it is seasonal or ephemeral or appearing irregularly.
Additional tags may help to better define situation. For specifying seasonal variations seasonal=* may be used in addition to intermittent=yes, Proposed features/ephemeral is intended to add similar tagging allowing to add info about ephemeral water presence.
Sometimes it is claimed that word "intermittent" has meaning that excludes regular changes and it is supported by some definitions. But some define this word in way that includes also regular changes, for example "occurring occasionally or at regular or irregular intervals" (example from Collins). In general, terminology is not shared by everybody - for example Wikipedia entry for "stream" considers "intermittent" and "seasonal" to be synonyms in case of streams while in OSM seasonal is a special case of intermittent and some consider seasonal and intermittent to cover separate classes of how water presence changes.
How to map
- waterway=river + intermittent=yes
- waterway=stream + intermittent=yes
- waterway=ditch + intermittent=yes
- waterway=drain + intermittent=yes
- waterway=canal + intermittent=yes
- Water areas