[Tagging] Feature Proposal - RFC - waterway=tidal_channel

Warin 61sundowner at gmail.com
Sat Jul 6 23:51:40 UTC 2019

On 07/07/19 00:38, Joseph Eisenberg wrote:
>> How are handled the concepts of intermittence and direction of the flow in
>> the tagging?
>> Should we use intermittent=yes and direction=both, or are they implied by
>> waterway=tidal_channel?
>> ...only recommend the use of intermittent=yes on
>> channels which are fully empty at low tide time.
> Thank you for bringing this up
> I agree that most tidal channels are not intermittent, because they
> tend to have a small amount of water flowing towards the sea at low
> tide. It could be reasonable to use intermittent=yes on small tidal
> channels that are completely dry at low tide.

These area of no water at low tide could be better mapped if OSM had a method for tagging the low tide mark.
Would be handy for some beaches, particularly where the tide is large and the area has a small slope creating a large area between high and low tides.

> Bidirectional water flow (that is, the direction of water flow
> reverses at different times in the tidal cycle) should be implied by
> the tag waterway=tidal_channel, though there may be rare exceptions.annel'.

If the flow is not 'tidal' then it should not be tagged 'tidal_channel". No exceptions?

> I don't know if the tag "direction=both" is used commonly with
> waterways. There's no wiki page to describe this tag, and the page
> Key:direction doesn't mention direction=both, though it's used 20,000
> times. More common is to add the tag "tidal=yes" to river estuaries
> which are clearly affected by the tides, though this does not
> necessary require reversal of water flow direction.
> The wiki page for waterway=tidal_channel should mention that
> "tidal=yes" is implied.
> -Joseph
>> Other channels will have a lower level but won't be empty.
>> Let me know how do you feel about this
>> All the best
>> François
>> Le sam. 6 juil. 2019 à 14:43, Joseph Eisenberg <joseph.eisenberg at gmail.com>
>> a écrit :
>>> I'd like to vote on the proposal for waterway=tidal_channel soon
>>> If you haven't read the page yet, please check and add any  comments
>>> or bring up any problems that might have been missed.
>>> https://wiki.openstreetmap.org/wiki/Proposed_features/Tag:waterway%3Dtidal_channel
>>> "Definition:    A natural intertidal waterway in mangroves, salt marshes
>>> and tidal flats with water flow in the direction of the tide"
>>> -Joseph

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