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<div class="moz-cite-prefix"><a class="moz-txt-link-freetext"
href="https://wiki.openstreetmap.org/wiki/DE:Key:waterway">https://wiki.openstreetmap.org/wiki/DE:Key:waterway</a>
says:<br>
- drain is for rain or industrial water ("Abwassergraben") ->
may be wastewater<br>
- ditch is just for rain water ("Entwässerungsgraben") -> no
wastewater<br>
<br>
Am 11.1.2019 07:35, schrieb John Willis:<br>
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<blockquote cite="mid:40B35264-92CF-4D44-A577-D8C70C19C648@mac.com"
type="cite">
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<div class="">On Jan 11, 2019, at 3:00 PM, Marc Gemis <<a
moz-do-not-send="true" href="mailto:marc.gemis@gmail.com"
class="">marc.gemis@gmail.com</a>> wrote:</div>
<br class="Apple-interchange-newline">
<div class=""><span class=""><span
class="Apple-converted-space"> </span>was always under
the impression that the ones I encounter between</span><br
class="">
<span class="">farmland and meadows, which typically are
surrounded by dirt, ground,</span><br class="">
<span class="">plants are ditches. That drains are
constructed with concrete or</span><br class="">
<span class="">similar material and that there are normally
no plants on the bedding</span><br class="">
<span class="">of the drain.</span></div>
</blockquote>
<br class="">
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<div>TL;DR - the connotation of “drain” is a problem. it is not
“draining away” unwanted water, it is merely moving it around,
and this connotation causes mapping issues. </div>
<div><br class="">
</div>
<div class="">~~~~</div>
<br class="">
<div class="">I like this summary too. I think the issue is that
“drain” has a connotation of moving water “away” from some spot
where it is no longer needed or has been used - which is
confusing for a lot of irrigation uses.</div>
<div class=""><br class="">
</div>
<div class="">In places like southern California, which only have
large (5x5m) open-air aqueduct systems to move usable water, and
further distribution handled almost 100% by pipe for irrigation
or drinking. sewer is also piped and handled by treatment
plants, and “storm drains" merely channel the occasional rain to
the ocean.</div>
<div class=""><br class="">
</div>
<div class="">This makes mapping “drains” and "ditches” is super
easy, because almost all drains/ditches are moving unwanted
rainwater to a waterway/ocean.</div>
<div class=""><br class="">
</div>
<div class="">but in my area of Japan, each neighborhood has
several *Kilometers* of tiny concrete roadside “drains” (covered
and uncovered) that have little doors or valves that farmers can
open to flood ditches that flood rice fields. there are side
channels, small storage ponds (3x3m), and other very detailed
and intricate water management systems that make a Californian
like me marvel at the rain management system they have created.
The drains act merely as storm drains the rest of the year, and
integrate “streams” and other natural channels sometimes. but
the rain they move is useful for irrigation; rain “drained” away
from my area is actually irrigation water for people further
downstream. </div>
<div class=""><br class="">
</div>
<div class="">the other issue is scale. some concrete drains are
very tiny measure less than 20cm2, though most are 30cm2 or
50cm2 . most ditches are also roughly 30cm2. </div>
<div class=""><br class="">
</div>
<div class="">if we go by construction, and try to remove
connotation of wastewater, then I think it is easy to map. </div>
<div class=""><br class="">
</div>
<div class=""> </div>
<div class="">Javbw</div>
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</blockquote>
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