How to tag permanent dry bodies of water?

EvertonBortolini · 2022-12-16T00:04:09.766Z

How to tag permanent dry bodies of water as dry abandoned meanders?

Fizzie41 · 2022-12-16T00:12:22.861Z

Are they permanently dry, as in they will never run again, or have they just been dry for quite a while, but when it rains sufficiently well “up there”, the rivers will run again?

EvertonBortolini · 2022-12-16T00:20:17.253Z

In this case, if it rains sufficiently, yes, they will run again.

Fizzie41 · 2022-12-16T00:23:01.544Z

In that case, waterway=stream + intermittent=yes should fix it.

EvertonBortolini · 2022-12-16T00:33:38.554Z

I have doubts about tagging with intermittent=yes, because these dry bodies of water are not seasonal, they will run sometimes.

ezekielf · 2022-12-16T01:13:26.698Z

Right now, intermittent=yes is the ~~only~~ (edit: most commonly used) established tag for features that are sometimes water covered and sometimes not. I could see how some additional nuance could make sense to distinguish a stream that is dry in one season and wet in another from one that has water only a few times in a decade. How often might are the ones in question have water?

EvertonBortolini · 2022-12-16T01:29:25.805Z

Only in a flood. But I need a tag that is not the same as the rest of the floodplain.

SomeoneElse · 2022-12-16T01:33:29.742Z

Zeke Farwell:

Right now, intermittent=yes is the only established tag for features that are sometimes water covered and sometimes not

(pedant alert)
There’s “flood_prone” too, and a bunch of basin features are by their very nature intermittent too.

In this case though, as you say, " intermittent=yes" sounds like the best tag.

Edit: I might as well link to an example of a map rendering that tries to differentiate between them. At that link, solid blue is water all the time, closely spaced blue hatching is “intermittent=yes” (if it rains a lot, that’ll be under water), and the widely spaced blue hatching is flood_prone=yes (if the river floods (less often than heavy rain), that area will be under water).

ezekielf · 2022-12-16T02:00:44.131Z

SomeoneElse:

There’s “flood_prone” too, and a bunch of basin features are by their very nature intermittent too.

Oh good point. I spoke too soon

EvertonBortolini · 2022-12-16T02:07:42.450Z

Thanks, @Fizzie41, @ezekielf, and @SomeoneElse for the help!

In conclusion, I think this is the better possible tag scheme for this situation. Perhaps, a tag is missing to define seasonality, such as seasonal=yes or seasonal=no (these tags do not exist), for bodies of water with intermittent=yes.

SomeoneElse:

I might as well link to an example of a map rendering that tries to differentiate between them. At that link, solid blue is water all the time, closely spaced blue hatching is “intermittent=yes” (if it rains a lot, that’ll be under water), and the widely spaced blue hatching is flood_prone=yes (if the river floods (less often than heavy rain), that area will be under water).

SomeoneElse · 2022-12-16T02:16:39.796Z

Just for info - a seasonal tag is fairly widely used and is often combined with intermittent.

Fizzie41 · 2022-12-16T02:52:36.759Z

I was also going to mention seasonal, but I thought that from your description - been dry for many years, that it wouldn’t apply!

EvertonBortolini · 2022-12-16T02:53:46.647Z

Great @SomeoneElse ! I searched by seasonal and didn’t find it.

EvertonBortolini · 2022-12-16T03:05:16.758Z

Context: These bodies of water are in the Lower São Francisco River in Brazil. 40 years ago, they were seasonal. But, in recent years no more, because there is a dam in the river.