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Log flume in Sweden, August 2010 Havla bruk sagverket.jpg
Log flume in Sweden, August 2010

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. [1] [2] 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.[ citation needed ] Flumes route water from a diversion dam or weir to a desired materiel collection location. Flumes are usually made up of wood, metal or concrete.


Many flumes took[ when? ] 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 industry, known as a log flume. They were also extensively used in hydraulic mining and working placer deposits for gold, tin and other heavy minerals.


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. [3]

Types of flumes

Bull Run Hydroelectric Project diversion flume, carrying water from one reservoir to another. Flume Little Sandy River.JPG
Bull Run Hydroelectric Project diversion flume, carrying water from one reservoir to another.
Working irrigation flume under repair in the East Kootenay, British Columbia Canada. Built in 1912, it runs 8km to provide water to a few dozen farms. Irrigation Flume.jpg
Working irrigation flume under repair in the East Kootenay, British Columbia Canada. Built in 1912, it runs 8km to provide water to a few dozen farms.


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

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

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. [4]

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). [5]

Flumes offer distinct advantages over sharp-crested weirs: [4]

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.[ citation needed ]

A bypass flume on the Chesapeake and Ohio Canal Bypass Flume Lock 7 C and O Canal.jpg
A bypass flume on the Chesapeake and Ohio Canal

In some nineteenth-century canals, a bypass flume diverted water around a lift lock from the level (or pound) above to the level below the lock, so that the level below would have sufficient water. [6]

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.

See also

Related Research Articles

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Hydropower, also known as water power, is the use of falling or fast-running water to produce electricity or to power machines. This is achieved by converting the kinetic energy of water into electrical or mechanical energy. Hydropower is a form of sustainable energy production.


A leat is the name, common in the south and west of England and in Wales, for an artificial watercourse or aqueduct dug into the ground, especially one supplying water to a watermill or its mill pond. Other common uses for leats include delivery of water for hydraulic mining and mineral concentration, for irrigation, to serve a dye works or other industrial plant, and provision of drinking water to a farm or household or as a catchment cut-off to improve the yield of a reservoir.

Hydraulics Fluid engineering and fluid mechanics

Hydraulics is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concerns gases. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the applied engineering using the properties of fluids. In its fluid power applications, hydraulics is used for the generation, control, and transmission of power by the use of pressurized liquids. Hydraulic topics range through some parts of science and most of engineering modules, and cover concepts such as pipe flow, dam design, fluidics and fluid control circuitry. The principles of hydraulics are in use naturally in the human body within the vascular system and erectile tissue. Free surface hydraulics is the branch of hydraulics dealing with free surface flow, such as occurring in rivers, canals, lakes, estuaries and seas. Its sub-field open-channel flow studies the flow in open channels.

Stream gauge Location used to monitor surface water flow

A stream gauge, streamgage or stream gauging station is a location used by hydrologists or environmental scientists to monitor and test terrestrial bodies of water. Hydrometric measurements of water level surface elevation ("stage") and/or volumetric discharge (flow) are generally taken and observations of biota and water quality may also be made. The location of gauging stations are often found on topographical maps. Some gauging stations are highly automated and may include telemetry capability transmitted to a central data logging facility.

Weir Artificial river barrier

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 river level. They are also used to control the flow of water for outlets of lakes, ponds, and reservoirs. There are many weir designs, but commonly water flows freely over the top of the weir crest before cascading down to a lower level.

Sluice A water channel controlled at its head by a gate

A sluice is a water channel controlled at its head by a gate. A mill race, leet, flume, penstock or lade is a sluice channelling water toward a water mill. The terms sluice, sluice gate, knife gate, and slide gate are used interchangeably in the water and wastewater control industry.

Imperial Dam Dam in Lower Colorado River ValleyImperial County, CaliforniaYuma County, Arizona

The Imperial Diversion Dam is a concrete slab and buttress, ogee weir structure across the California/Arizona border, 18 miles (29 km) northeast of Yuma. Completed in 1938, the dam retains the waters of the Colorado River into the Imperial Reservoir before desilting and diversion into the All-American Canal, the Gila River, and the Yuma Project aqueduct. Between 1932 and 1940, the Imperial Irrigation District (IID) relied on the Inter-California Canal and the Imperial Canal and Alamo River.

The Manning formula is an empirical formula estimating the average velocity of a liquid flowing in a conduit that does not completely enclose the liquid, i.e., open channel flow. However, this equation is also used for calculation of flow variables in case of flow in partially full conduits, as they also possess a free surface like that of open channel flow. All flow in so-called open channels is driven by gravity. It was first presented by the French engineer Philippe Gauckler in 1867, and later re-developed by the Irish engineer Robert Manning in 1890.


Stoplogs are hydraulic engineering control elements that are used in floodgates to adjust the water level or discharge in a river, canal, or reservoir. Stoplogs are sometimes confused with flashboards, as both elements are used in bulkhead or crest gates. Stoplogs are typically long rectangular timber beams or boards that are placed on top of each other and dropped into premade slots inside a weir, gate, or channel. Present day, the process of adding and removing stoplogs is not manual, but done with hydraulic stop log lifters and hoists. Since the height of the barrier can only be adjusted through the addition and removal of stoplogs, finding a lighter and stronger material other than wood or concrete became a more desirable choice. Other materials, including steel and composites, can be used as stoplogs as well. Stoplogs are designed to cut off or stop flow through a conduit.

A hydraulic structure is a structure submerged or partially submerged in any body of water, which disrupts the natural flow of water. They can be used to divert, disrupt or completely stop the flow. An example of a hydraulic structure would be a dam, which slows the normal flow rate of the river in order to power turbines. A hydraulic structure can be built in rivers, a sea, or any body of water where there is a need for a change in the natural flow of water.

A venturi flume is a critical-flow open flume with a constricted flow which causes a drop in the hydraulic grade line, creating a critical depth.

Shushtar Historical Hydraulic System Complex irrigation system from the Sassanid era, island city Shushtar, Iran

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Ablach (Danube) River in Germany

The Ablach is a right tributary of the Danube. It rises on the European Watershed, which is only a hint in this area, from the Mindersdorfer Aach in the municipality of Hohenfels in the Landkreis of Konstanz. It is about 32 kilometres (20 mi) long.

Parshall flume Hydraulic structure for measuring fluid flow

The Parshall flume is an open channel flow metering device that was developed to measure the flow of surface waters and irrigation flows. The Parshall flume is a fixed hydraulic structure. It is used to measure volumetric flow rate in industrial discharges, municipal sewer lines, and influent/effluent flows in wastewater treatment plants. The Parshall flume accelerates flow through a contraction of both the parallel sidewalls and a drop in the floor at the flume throat. Under free-flow conditions the depth of water at specified location upstream of the flume throat can be converted to a rate of flow. Some states specify the use of Parshall flumes, by law, for certain situations.

Cutthroat flume

The Cutthroat flume is a class of flow measurement flume developed during 1966/1967 that is used to measure the flow of surface waters, sewage flows, and industrial discharges. Like other flumes, the Cutthroat flume is a fixed hydraulic structure. Using vertical sidewalls throughout, the flume accelerates flow through a contraction of sidewalls until the flow reaches the "throat" of the flume, where the flow is then expanded. Unlike the Parshall flume, the Cutthroat flume lacks a parallel-walled throat section and maintains a flat floor throughout the flume.

Yuba–Bear Hydroelectric Project

The Yuba–Bear Hydroelectric Project is a complex hydroelectric scheme in the northern Sierra Nevada in California, tapping the upper Yuba River and Bear River drainage basins. The project area encompasses approximately 400 square miles (1,000 km2) in Nevada, Placer, and Sierra Counties. Owned by the Nevada Irrigation District, it consists of 16 storage dams plus numerous diversion and regulating dams, and four generating stations producing 425 million kilowatt hours of electricity each year. The Yuba–Bear Hydroelectric Project consists of the Bowman development, Dutch Flat No. 2 development, Chicago Park development, and Rollins development.

Montana flume

A Montana flume, is a popular modification of the standard Parshall flume. The Montana flume removes the throat and discharge sections of the Parshall flume, resulting a flume that is lighter in weight, shorter in length, and less costly to manufacture. Montana flumes are used to measure surface waters, irrigations flows, industrial discharges, and wastewater treatment plant flows.

Palmer-Bowlus Flume

The Palmer-Bowlus flume, is a class of flumes commonly used to measure the flow of wastewater in sewer pipes and conduits. The Palmer-Bowlus flume has a u-shaped cross-section and was designed to be inserted into, or in line with, pipes and u-channels found in sanitary sewer applications.

Upper Canal System

The Upper Canal System, also called the Southern Railway Aqueduct and the Cataract Tunnel, is a heritage-listed operational gravity-fed aqueduct that supplies some of the potable water for Sydney, in New South Wales, Australia. The aqueduct comprises 54 kilometres (34 mi) of open canals, tunnels, and closed pipelines that connect the Upper Nepean Scheme with the Prospect Reservoir. The aqueduct is managed by the Sydney Catchment Authority on behalf of WaterNSW, an agency of the Government of New South Wales. It was listed on the New South Wales State Heritage Register on 18 November 1999.

Holyoke Testing Flume

The Holyoke Testing Flume was a hydraulic testing laboratory and apparatus in Holyoke, Massachusetts, operated by the Holyoke Water Power Company from 1870 to 1932, and used to test the performance of water turbine designs, completing 3,176 tests of efficiency in that time. It was described by Robert E. Horton in court testimony as the only facility of its kind in the 19th and early 20th century, which made possible the standardization of American water turbines. Indeed Clemens Herschel, who managed and redesigned the facility in the 1880s, later described it in Congressional testimony as the "first modern hydraulic laboratory" in the United States and the world. It was through Herschel's need to determine the water power consumption of different mills, and in this testing system that he would invent the Venturi meter, the first accurate means of measuring large-scale flows, which still retains widespread use in modern technology today.


  1. Koester, Frank (1909). Hydroelectric Developments and Engineering. New York: D. Van Nonstrand. pp.  40–45.
  2. Guidelines for Identifying, Evaluating and Registering Historic Mining Sites. Washington, D.C.: National Park Service, U.S. Department of the Interior. 1997.
  3. Wikisource-logo.svg One or more of the preceding sentences incorporates text from a publication now in the public domain : Chisholm, Hugh, ed. (1911). "Flume". Encyclopædia Britannica . 10 (11th ed.). Cambridge University Press. pp. 574–575.
  4. 1 2 Flumes, Openchannelflow.com
  5. Sections of a Flume - Their Location and Function, Openchannelflow.com
  6. Kytle, Elizabeth (1983). Home on the Canal . Cabin John, MD: Seven Locks Press. ISBN   978-080185328-9. p. 270

Further reading