A reach is a segment of a stream, river, or
arm of the sea, usually suggesting a straight, level, uninterrupted stretch.
They are traditionally defined by the
capabilities of sailing boats, as a stretch of a watercourse which, because it is straightish, can be sailed in one "
reach" (that is, without
tacking).
Reaches are often named by those using the river, and a reach may be named for landmarks, natural features, and historical reasons (see, for instance,
Gallions' Reach, named after the family that once owned its banks).
A reach may be an expanse, or widening, of a stream or river channel. This commonly occurs after the river or stream is dammed. A reach is similar to an
arm, though an arm may bend and thus have multiple reaches. The term "reach" can also refer to a level stretch, as between river rapids or locks in a
canal
Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface ...
. The word may also be used more generally to refer to any extended portion or stretch of land or water, or even metaphorically.
In
fluvial
A river is a natural stream of fresh water that flows on land or inside caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of its course if it ru ...
hydrology
Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydro ...
, a reach is a convenient subdivision of study; it may be any length of river of fairly uniform characteristics, or the length between
gauging stations, or simply the length of a watercourse between any two defined points. These may be measured in terms of
river miles.
As of 2015, the
US Board on Geographic Names records 334 place names in the US with the characterization of a named "reach".
USGS Survey GNIS Database
/ref>
Gallery
Image:Hanford Reach.jpg, Example: Hanford Reach National Monument, Washington State, US. The last significant free-running (undammed) section of the Columbia River in the US
File:River Thames Reaches.jpg, A map of the reaches of the River Thames; it can be seen that a reach is a straightish stretch (and can therefore be sailed in one reach, one straight-line path between tacks, unless the wind is too close to head-on to allow the sailing-boat to reach)
File:Barge Match (Thames River) RMG PY4069.tiff, Thames barges reaching on the Thames during a race; they are probably on Gravesend Reach
See also
*Meander
A meander is one of a series of regular sinuous curves in the Channel (geography), channel of a river or other watercourse. It is produced as a watercourse erosion, erodes the sediments of an outer, concave bank (cut bank, cut bank or river cl ...
* Rapid
* Stream pool
References
{{DEFAULTSORT:Reach (Geography)
Physical geography
Fluvial landforms
Rivers
Water streams
Hydrology