[Tagging] Tagging Digest, Vol 108, Issue 162

Michael Patrick geodesy99 at gmail.com
Fri Sep 28 05:05:18 UTC 2018

> It would seem odd to tag a bend as a reach, as the classic definition of
a reach is 'A portion of a river, channel, or lake which lies between two
bends or which can be seen in one view'.

Which is why the first sentence the USGS definition is: “Reach” can
have *slightly
different meanings*, depending on how it is used.

Since USGS is the custodian of the Geographic Names Information System
<https://geonames.usgs.gov/domestic/> (GNIS) and also the hydrology models,
they probably have a better overview of where and how it's applied ranging
from common / historical names to strict scientific terminology.

One that came to my mind which has no straightness component at all was the
Hanford Reach on the Columbia River: *" The Hanford Reach
<https://en.wikipedia.org/wiki/Hanford_Reach> is a free-flowing section of
the Columbia River, around 51 miles (82 km) long, in eastern Washington
state. It is named after a large northward bend in the river's otherwise
southbound course."*

I.e. that single bend is the 'reach' :-) The Mississippi River Reaches
are hundreds of miles long and include many straight log sections, bends

I also have an U.S. Navy COLREGS book "Collision Prevention" on my table
here where their use is exactly according to the definition you mention
based on 'visibility'. And close to other nautical meanings like a sailing
'reach', being the longest clear path achievable without obstruction under
given conditions.

One source gives the 1520s as the earliest use, referring to stretches of
water.There weren't to many straight stretches of water back then, even the
canals in Venice and Amsterdam were pretty organic. :-)

It seams it can be applied in any ad hoc way to any water between two
locations, even nested and overlapping manners, at any scale. Precise
ambiguity, good for OSM. :-)

Michael Patrick
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