My main suggestion would be to re-use the same scheme as Key:opening_hours to define the time when the waterway is likely to flow. I would also discard rare/frequent as too subjective. Instead: approximate duration are not perfect but should improve mutual understanding.
For instance as in: waterway = * + intermittent = yes | no | periodical | random (default:no) ++ intermittent:periodical = [opening_hours scheme] (likely to flow at this date) eg. Mar-Jun | OR | Nov 20-Feb 20 | OR | ... ++ intermittent:random:interval = [approximate duration] (typical/assumed duration between two flowing events) eg. 2 weeks | OR | 3 years | OR | ... ++ intermittent:random:duration = [approximate duration] (typical/assumed duration of one flowing event) eg. 12 hours | OR | 3 days | OR | ... I am sure some people would like to go in more details, so why not: + intermittent:origin = rain | snowmelt | geothermal | ... + intermittent:effect = stream | torrential | flood | ... Mateusz Konieczny <matkoni...@gmail.com> wrote: > Please, no "intermittent=ephemeral". Key intermittent was defined to have > only a single valid value, turning it into free-form tag is a bad idea. > > Maybe intermittent=yes, intermittent:type=ephemeral? Maybe other tags began with a key and a single valid value. Afterwards they evolved to multiple valid values for added details and nuances. Multiple valid values [option1|option2|...|optionN] is not the same as free-form [name/note/source/description=*], is it? _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging