Just wondering how you go about marking a river as "walkable"? There's some near me which are almost _always_ dry and I've tagged them as intermittent, but there's no option to set them as pedestrian accessible. At least, none that I can find. It occurs to me that there's often trails which will follow a riverbank edge for a while as well, would it make sense to me if those river sections could also be marked as walkable?
Neither the default map rendering nor error checking in JOSM deal well with the combination of highway=* and waterway=* on the same way. But it does match what is “on the ground” so I ignore the JOSM warnings and realize that most maps won’t have it rendered as I might like.
At least one will (at least, for similar sorts of things mapped in the UK) - https://map.atownsend.org.uk/maps/map/map.html#zoom=19&lat=51.372163&lon=-2.494023 . I used an extra-wide casing of the road to indicate ford, sidewalk or verge instead of bridge. The style’s available if you want to have a go at rendering a map of any of your desert tracks - see the links from the changelog at the top of that link.
This solution doesn’t work if one of highway or waterway or both has a name, which is true in most cases. In your example (https://www.openstreetmap.org/way/193001272) you ommited the waterways name “Bathford Brook” and gave the waterway the name “Tuckingmill Lane” too.
Not my particular example, but you do point out an issue with the tagging I suggested. Fortunately, I’ve not come across this situation in the areas I’ve mapped. Generally the locals use the name of the waterway if it has one. So a local might say something like “go 6 miles on the Charouleau Gap road to where it crosses Dodge Wash, go up the wash about a half mile and the four wheel drive road leaves the wash on going up a ridge on the right side.”
Unfortunately, as far as I can tell OSM hasn’t yet come up with a way of having an array of values for a single tag. So as a first step, I’d suggest using the name tag for whatever the locals are more likely to call it and the alt_name tag for the other option. If there are more than two names, then this scheme would fail.
I suppose one could use route relations for both the stream and the track and have them reuse the same way. But I am not sure how common or supported that form of tagging is.
What’s more usual than a string of semicolon-separated names is to use specfic tags for specific names. See e.g. https://www.openstreetmap.org/way/53247094 (though depending on contect “:” is often used instead of “_”). Maps that want to process that information can then do so. See for example: