A flume is a human-made channel for water, in the form of an open declined gravity chute whose walls are raised above the surrounding terrain, in contrast to a trench or ditch. Flumes are not to be confused with aqueducts, which are built to transport water, rather than transporting materials using flowing water as a flume does. Flumes route water from a

diversion dam A diversion dam is a dam that diverts all or a portion of the flow of a river from its natural course. Diversion dams do not generally impound water in a reservoir; instead, the water is diverted into an artificial water course or canal, which ...

or weir to a desired materiel collection location. Flumes are usually made up of wood, metal or concrete. Many flumes took the form of wooden troughs elevated on trestles, often following the natural contours of the land. Originating as a part of a mill race, they were later used in the transportation of logs in the

logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. Logging is the beginning of a supply chain ...

industry, known as a log flume. They were also extensively used in

hydraulic mining Hydraulic mining is a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment.Paul W. Thrush, ''A Dictionary of Mining, Mineral, and Related Terms'', US Bureau of Mines, 1968, p.560. In the placer mining of ...

and working placer deposits for gold, tin and other heavy minerals.

Etymology

The term ''flume'' comes from the Old French word ''flum'', from the Latin ''flumen'', meaning a river. It was formerly used for a stream, and particularly for the tail of a mill race. It is used in America for a very narrow gorge running between precipitous rocks, with a stream at the bottom, but more frequently is applied to an artificial channel of wood or other material for the diversion of a stream of water from a river for purposes of irrigation, for running a sawmill, or for various processes in the hydraulic method of gold-mining.

Types of flumes

Millrace

A diversionary flume is used to transfer water from one body to another, such as between two reservoirs.

Log flume

Log flumes use the flow of water to carry cut logs and timber downhill, sometimes many miles, to either a sawmill or location for further transport.

Flow measurement flume

Some varieties of flumes are used in measuring water flow of a larger channel. When used to measure the flow of water in open channels, a flume is defined as a specially shaped, fixed hydraulic structure that under free-flow conditions forces flow to accelerate in such a manner that the flow rate through the flume can be characterized by a level-to-flow relationship as applied to a single head (level) measurement within the flume. Acceleration is accomplished through a convergence of the sidewalls, a change in floor elevation, or a combination of the two.Flumes
Openchannelflow.com Flow measurement flumes typically consist of a converging section, a throat section, and a diverging section. Not all sections, however, need to be present. In the case of the Cutthroat flume, the converging section directly joins the diverging section, resulting in a throat section of no length (hence the term "Cutthroat"). Other flumes omit the diverging section (Montana, USGS Portable Parshall, and HS / H / HL flumes).Sections of a Flume - Their Location and Function
Openchannelflow.com Flumes offer distinct advantages over sharp-crested weirs: *For the same control width, the head loss for a flume is about one-fourth of that needed to operate a sharp-crested weir *The velocity of approach is part of the calibration equations for flumes *Unauthorized altering of the dimensions of constructed flumes is difficult (and therefore unlikely) *Most flume styles readily allow for the passage of sedimentation and floating debris – reducing the time and effort associated with maintaining a flume installation Styles of flow measurement flumes include: Cutthroat, HS / H / HL-type, Khafagi, Montana, RBC, Parshall, Palmer-Bowlus, Trapezoidal, and Venturi Flume. Flow measurement flumes can be installed in earthen channels, concrete canals, below ground chambers, or factory integrated into Packaged Metering Manholes.

Navigable canal flume

200px, A bypass flume on the Chesapeake and Ohio Canal In some nineteenth-century canals, a bypass flume diverted water around a

lift lock A boat lift, ship lift, or lift lock is a machine for transporting boats between water at two different elevations, and is an alternative to the canal lock. It may be vertically moving, like the Anderton boat lift in England, rotational, like ...

from the level (or pound) above to the level below the lock, so that the level below would have sufficient water. p. 270

Recreational flumes

In competitive swimming, specialized flumes with transparent sides are often employed by coaches to analyze a swimmer's technique. The speed of the flow is variable to accommodate the full spectrum of swimming styles and ability.

Gallery

Flume, Hafren Forest - geograph.org.uk - 228904.jpg, Measuring flume in the UK Gold Creek, AK, with pipe.jpg, Flume outflow Creek diversion above the southern portal of Woy Woy tunnel.jpg, A temporary flume in New South Wales

References

External links

{{Rivers, streams and springs Aqueducts