Hi, Pierre:
I find that idea very good indeed. The only issue is to know what the
frequence/probability is. If we know that I would definitely go for this
solution.
I guess that this won't be possible for the huge majority of rivers and
streams, but maybe for this one there is somewhere a record of what
years it has carried water.
Cheers,
Rafael.
O 09/04/20 ás 17:48, Pierre Béland escribiu:
Hi Rafael
I am not an hydrologist either, but I think that for such rivers we
could use the key intermittent adding to it a value that refer to the
periodicity of water resurgence. For risk of floodings, we generally
use in Canada probability of flooding in the
- next 20 years
- next 100 years.
What about something like intermittent=decade, centennial ?
Pierre
Le jeudi 9 avril 2020 10 h 49 min 58 s UTC−4, Rafael Avila Coya
<[email protected]> a écrit :
Hi:
I've consulted a colleague expert in hydrology, and he told me about
these fosil rivers:
"The term fosil rivers is not widely used "scientifically", they are
rather called Paleo channels and it is for rivers that have dried up
since 1000s of years and most of these paleo rivers are buried or filled
with sediments.
If a river gets dry for any reason (let say for some decades ) but u
could still see the river course (which is only possible in very rare
occasions) u could still call it a river just to maintain the landmark
notation and geography."
I am not an expert, and I would do what Arne suggest if I was mapping
without discussing this with anybody, but still, like Arne, I see the
lack of a tag for these kind of rivers.
As for the Lagh Dara, this colleague has sent me two images of the
rivers passing by Afmadow town.
One shows the river as we can see it normally: https://flic.kr/p/2iNyA5a
But the second shows how it was during the 2018 devastating floodings:
https://flic.kr/p/2iNyA7z
He has been on UN missions in Somalia many times, so he has too on the
ground knowledge.
By the way: the Lagh Dera river geometry is right now of very poor
geometry in OSM, while the UNSOS one is very good in comparison:
https://flic.kr/p/2iNyQ6G
Cheers,
Rafael.
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