[Tagging] [Tagging ] How to tag a paleochannel of a river

Bert -Araali- Van Opstal bert.araali.afritastic at gmail.com
Sat Mar 13 08:04:08 UTC 2021


We could look at it and designate these features how they develop over 
time, apply tagging accordingly.

As long as the meander of the river contains flowing water, either 
permanently or intermittent/seasonally it remains a river and we have 
sufficient tagging to distinguish those with natural=water and waterway.

If the meander becomes cut off from the main river flow, so no longer 
contains open flowing water we had no specific tagging, but I do like 
the oxbow term for that, although it never went through a proposal 
process. Maybe we should promote it's use by referring to it from other 
wiki pages.

Over time these oxbows due to sedimentation turn into wetlands.  Also 
there I believe we have sufficient tagging possibilities.

Many of these "wetlands" get drained and reclaimed for human purposes.  
Others are directly reclaimed from water bodies like the sea, lakes but 
also rivers. Those we tag with landuse.
landuse=farmland seems the correct tag here. We do already use it for 
irrigated and drained land by identifying the crops grown there, like 
for rice and paddy rice fields. We also have separate landuse tags for 
specific farmland, like orchard and vineyard.
As far as I know we don't have a specific landuse tag to those purposely 
reclaimed farmlands from water bodies.  Different crops can grow on it 
and may are use as pastures.
A worldwide term however exists: polder 
(https://en.wikipedia.org/wiki/Polder 
<https://en.wikipedia.org/wiki/Polder>). So maybe the time and occasion 
is right to introduce landuse=polder.

Greetings,

Bert Araali

On 13/03/2021 00:41, Paul Allen wrote:
> On Fri, 12 Mar 2021 at 20:33, Volker Schmidt <voschix at gmail.com 
> <mailto:voschix at gmail.com>> wrote:
>
>     There is another class of fossil oxbows, that are older, even
>     often many thousands of year older, and have silted up completely,
>     but they often are still visible in their contours, even if only
>     for the fact that the fertility of the silted-in part is different
>     because different crops grown there. I think that's what the term
>     paleochannel refers to.
>
>
> The mechanism and appearance of paleochannels are different from
> oxbow lakes, as I understand the wikipedia articles.  But I could be
> wrong about that.
>
>
>     Question to native English speakers: are there other terms in this
>     context, which may be more suitable or the dried-up variety?
>
>
> Oxbow lakes can persist hundreds of years before they transform into
> swamps or bogs (and at that stage should probably be mapped as such.
> I don't think you can call it an oxbox lake if there's no water in 
> it.  You
> have a transition from water to swamp to bog to sub-surface differences
> that we probably can't map.  Maybe, if the surface is lower than
> the surroundings we could map that (except we don't really have a suitable
> tag) until the day comes when river flooding removes even that
> difference.
>
> -- 
> Paul
>
>
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