On 23/3/20 9:08 am, Volker Schmidt wrote:
On Sun, 22 Mar 2020 at 19:09, François Lacombe
<fl.infosrese...@gmail.com <mailto:fl.infosrese...@gmail.com>> wrote:
Hi Volker,
...
Fully disposed to make any improvement to wiki according to those
points.
Thanks, Francois.
There is possibly a language bias (error?) in the use of tunnel=flooded.
I am not a native speaker, but "flooded" to me means at least "more
water than normal", and from this discussion it seems that we are
talking about the normal presence of water in these structures.
Normal? No I don't think so. Some 'tunnels may be designed only to carry
water and have no real room for anything else. I am thinking of hydo
schemes where tunnels are used
To me 'tunnel=flooded' means that is cannot really be used for/by
anything other than the fluid in it due to the very small amount of
space left, if any.
Humm ... a smaller description? '"tunnel=flooded' ... full or nearly
full of fluid so that the tunnel cannot be used for anything else' ???
Tag use tunnel=flooded: 2 in the UK,
>> Many, if not the majority of the UK Inland Waterways canals have no
tow-path.
> Then tunnel=flooded is more appropriate.
No, definitely not. These tunnels are not "flooded" at all, the water
level in them is carefully controlled
(The original method of powering the boats in these canals were men
laying on their back and "walking" with their feet upwards along the
tunnel ceiling. The French canals, being constructed later, generally
did have tow-paths also in the tunnels see for example the
Tunnel_de_Mauvages
<https://www.google.com/url?sa=i&url=https%3A%2F%2Ffr.wikipedia.org%2Fwiki%2FTunnel_de_Mauvages&psig=AOvVaw3UK-_RmcKBM_5fKTGMZyjW&ust=1584997257128000&source=images&cd=vfe&ved=0CA0QjhxqFwoTCOijlIn9rugCFQAAAAAdAAAAABAS>.
I remember when I was a boy my father showed me the tractors pulling
the ships through the old tunnel near Arzwiller in Alsace on the same
canal)
They are uniformly tagged (correctly) as waterway=canal and tunnel=yes.
I mentioned them in the context that tunnel=yes does not imply a
tow-path.
I had glanced at yourHydropower water supplies proposal, but I think I
failed to intervene on three specific points:
1. The first one are the inverted siphons (botte sifone
<https://it.wikipedia.org/wiki/Botte_sifone>, pont-siphon
<https://fr.wikipedia.org/wiki/Pont-siphon>), which are
gravity-pressurised always-water-filled sections of non-navigable
canals. I usually map them as culverts, and i have just started to
add the new tag culvert=inverted_siphon to the first three of them.
2. The second point is that the distinction between water-filled and
part-filled water conducts is problematic: culverts that are
frequently used to conduct free-flowing drains, ditches,
irrigation canals, freshwater canals under roads can be anything
from empry to fully filled (and slightly pressurised) depending on
precipitations.
3. waterway=pressurised cannot be used together with waterway=canal
for the inverted-siphon situation
Volker
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