I strongly disagree. A wadi is usually only an active river through very rare 
flash flood events, and almost never any other time.  Entire biomes are defined 
by the presence of (and situated in) a wadi. 

In america, the words Arroyo and wash roughly translate into wadi, and because 
of the ambiguous nature of arroyo, the term wadi is used for a wash or arroyo 
when referring to a usually dry stream/riverbed that is dangerous in flash 
flood conditions. 

my experience with washes stems from the Southern California Desert, where most 
of the state park would basically be covered in blue, if washes were somehow 
labeled as rivers - some are 100m across.  Whole road systems exist in the 
washes (and are reestablished purely by use after a flood), as the rest of the 
land is almost impassable. 

I have driven a couple thousand miles in a roughly 50x50 mile box over a 
hundred or so driving trips, and only on 3 occasions was water ever present, 
and at that time, the roads were completely impassable (a meter or so of water 
filled up the Carrizo wash 30m wide).

Although several famous arroyos (like the LA River) are now basically man-made 
drainage ditches, mapping desert areas properly requires the wadi tag, as they 
are different from intermittent rivers - in the fact that water in the “bed" is 
*never expected* - even seasonally - and if present it is a dangerous flash 
flood. There is never an in-between state of what you would call “a river” for 
longer than a day. - as it disappears almost immediately as soon as the flood 
is over (except in the most exceptional of weather conditions).  - kind of like 
an avalanche is only an avalanche while it is moving, or an earthquake is is an 
event. 

A wadi is a place where flash floods occur. It is not an intermittent river - 
it isn’t really seasonally wet, and doesn’t provide any real expectation that 
water will be present (except deep underground) - because they are located in 
places where rain itself is unexpected for most of the year. 

A wadi has an expectation of always being dry, except for the rare and 
unpredictable flash flood. t and in that case, you should assume it is a 
dangerous, and impassable place. 

I think, espcially since it is defined and used so heavily, and has a different 
connotation than a river - even a intermittent one, it should be kept. 

a wash near Borrego springs, CA (ironwood wash, Tubb canyon). it drains to a 
sink in the middle of the desert (the white spot in the upper right)

https://www.flickr.com/photos/javbw/11091366554/in/set-72157638113734675 
<https://www.flickr.com/photos/javbw/11091366554/in/set-72157638113734675>

https://goo.gl/maps/fpSxE

Javbw


> On Jan 14, 2015, at 11:45 PM, Mateusz Konieczny <matkoni...@gmail.com> wrote:
> 
> waterway=wadi is used (18 180 times) and has some support (for example JOSM 
> and 
> default map style).
> 
> During implementing rendering of intermittent=yes I discovered major problem 
> with this tag -
> the same waterway=wadi may be used for completely dried up waterway, 
> intermittent stream,
> intermittent major river and intermittent ditch.
> 
> Therefore - it seems that using waterway=river/canal/stream/ditch/drain + 
> intermittent=yes is
> clearly superior to using waterway=wadi.
> _______________________________________________
> Tagging mailing list
> Tagging@openstreetmap.org
> https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
Tagging mailing list
Tagging@openstreetmap.org
https://lists.openstreetmap.org/listinfo/tagging

Reply via email to