A mill race, millrace or millrun,
mill lade (Scotland) or mill leat (Southwest England) is the current of water that turns a
water wheel
A water wheel is a machine for converting the kinetic energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a large wheel (usually constructed from wood or metal), with numerous b ...
, or the channel (
sluice) conducting water to or from a water wheel. Compared with the broad waters of a
mill pond, the narrow current is swift and powerful. The race leading to the water wheel on a wide stream or mill pond is called the head race (or headrace
[Dictionary.com, word definition]), and the race leading away from the wheel is called the tail race
[Chamber's Twentieth Century Dictionary, 1968, p=674] (or tailrace
).
A mill race has many geographically specific names, such as ''
leat,
lade, flume, goit, penstock''. These words all have more precise definitions and meanings will differ elsewhere. The original undershot waterwheel, described by
Vitruvius, was a 'run of the river wheel' placed so a fast flowing stream would press against and turn the bottom of a bucketed wheel.
In the first meaning of the term, the millrace was the stream; in the sense of the word, there was no separate channel, so no race.
The example of Mill Lade in
Godmanchester refers to a wide channel leading to moorings where laden vessels unload, similar waterways known by the similar name of
Lode exist in neighbouring districts.
As technology advanced, the stream was dammed by a
weir
A weir or low-head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the water level. Weirs are also used to control the flow of water for outlets of l ...
. This increased the head of water. Behind the weir was the
millpond, or lodge. The water was channelled to the waterwheel by a sluice or millrace- this was the head race. From the waterwheel, the water was channelled back to the course of the stream by a sluice known as the tail race. When the tail race from one mill led to another mill where it acted as the head race this was known as the mid race. The level of water in the millrace could be controlled by a series of sluice gates.
Image gallery
River Meon.
Cogglesford Mill race and bypass weir.JPG, Cogglesford Mill: a covered head race and the by-pass weir
15-19-077, mingus creek - panoramio.jpg, millrace for Mingus Mill
Johnson and Seymour Millrace.jpg, Johnson and Seymour Millrace from the Genesee River
See also
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Canal pound
A canal pound (from impound), reach, or level (American usage), is the stretch of level water impounded between two canal locks. Canal pounds can vary in length from the non-existent, where two or more immediately adjacent locks form a canal lock# ...
*
Leat
*
Penstock
*
Watermill
*
Water wheel
A water wheel is a machine for converting the kinetic energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a large wheel (usually constructed from wood or metal), with numerous b ...
References
External links
{{DEFAULTSORT:Mill Race
Watermills