River source

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River Wey near its source at Farringdon Wey source farringdon.jpg
River Wey near its source at Farringdon

The headwater of a river or stream is the farthest point on each of its tributaries upstream from its mouth/estuary into a lake/sea or its confluence with another river. Each headwater is considered one of the river's sources, as it is the place where surface runoffs from rainwater, meltwater and/or spring water begin accumulating into a more substantial and consistent flow that becomes a first-order tributary of that river. The tributary with the longest course downstream of the headwaters is regarded as the main stem.

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Definition

A stone near Crissolo, Italy, inscribed: Here is born the Po SorgentePo.jpg
A stone near Crissolo, Italy, inscribed: Here is born the Po

The United States Geological Survey (USGS) states that a river's "length may be considered to be the distance from the mouth to the most distant headwater source (irrespective of stream name), or from the mouth to the headwaters of the stream commonly known as the source stream". As an example of the second definition above, the USGS at times considers the Missouri River as a tributary of the Mississippi River. But it also follows the first definition above (along with virtually all other geographic authorities and publications) in using the combined Missouri—lower Mississippi length figure in lists of lengths of rivers around the world. [1] Most rivers have numerous tributaries and change names often; it is customary to regard the longest tributary or stem as the source, regardless of what name that watercourse may carry on local maps and in local usage.[ citation needed ]

This most commonly identified definition of a river source specifically uses the most distant point (along watercourses from the river mouth) in the drainage basin from which water runs year-around (perennially), or, alternatively, as the furthest point from which water could possibly flow ephemerally. [2] The latter definition includes sometimes-dry channels and removes any possible definitions that would have the river source "move around" from month to month depending on precipitation or ground water levels. This definition, from geographer Andrew Johnston of the Smithsonian Institution, is also used by the National Geographic Society when pinpointing the source of rivers such as the Amazon or Nile. A definition given by the state of Montana agrees, stating that a river source is never a confluence but is "in a location that is the farthest, along water miles, from where that river ends." [3]

Under this definition, neither a lake (excepting lakes with no inflows) nor a confluence of tributaries can be a true river source, though both often provide the starting point for the portion of a river carrying a single name. For example, National Geographic and virtually every other geographic authority and atlas define the source of the Nile River not as Lake Victoria's outlet where the name "Nile" first appears, which would reduce the Nile's length by over 900 km (560 mi) (dropping it to fourth or fifth on the list of world's rivers), but instead use the source of the largest river flowing into the lake, the Kagera River. Likewise, the source of the Amazon River has been determined this way, even though the river changes names numerous times along its course. [4] However, the source of the Thames in England is traditionally reckoned according to the named river Thames rather than its longer tributary, the Churn — although not without contention. [5]

When not listing river lengths, however, alternative definitions may be used. The Missouri River's source is named by some USGS and other federal and state agency sources, following Lewis and Clark's naming convention, as the confluence of the Madison and Jefferson Rivers, rather than the source of its longest tributary (the Jefferson). [3] This contradicts the most common definition, [6] which is, according to a US Army Corps of Engineers official on a USGS site, that "[geographers] generally follow the longest tributary to identify the source of rivers and streams." In the case of the Missouri River, this would have the source be well upstream from Lewis and Clark's confluence, "following the Jefferson River to the Beaverhead River to Red Rock River, then Red Rock Creek to Hell Roaring Creek."[ citation needed ]

Characteristics

Rhume Spring, source of the Rhume river Rhumequelle Rhumspringe.jpg
Rhume Spring, source of the Rhume river

Sometimes the source of the most remote tributary may be in an area that is more marsh-like, in which the "uppermost" or most remote section of the marsh would be the true source. For example, the source of the River Tees is marshland.

The furthest stream is also often called the head stream. Headwaters are often small streams with cool waters because of shade and recently melted ice or snow. They may also be glacial headwaters, waters formed by the melting of glacial ice.

Headwater areas are the upstream areas of a watershed, as opposed to the outflow or discharge of a watershed. The river source is often but not always on or quite near the edge of the watershed, or watershed divide. For example, the source of the Colorado River is at the Continental Divide separating the Atlantic Ocean and Pacific Ocean watersheds of North America.

Example

A river is considered a linear geographic feature, with only one mouth and one source. For an example, the Mississippi River and Missouri River sources are officially defined as follows:

The verb "rise" can be used to express the general region of a river's source, and is often qualified with an adverbial expression of place. For example:

The word "source", when applied to lakes rather than rivers or streams, refers to the lake's inflow. [7] [8]

See also

Related Research Articles

<span class="mw-page-title-main">Missouri River</span> Major river in central United States

The Missouri River is the longest river in the United States. Rising in the eastern Centennial Mountains of the Bitterroot Range of the Rocky Mountains of southwestern Montana, the Missouri flows east and south for 2,341 miles (3,767 km) before entering the Mississippi River north of St. Louis, Missouri. The river drains semi-arid watershed of more than 500,000 square miles (1,300,000 km2), which includes parts of ten U.S. states and two Canadian provinces. Although a tributary of the Mississippi, the Missouri River is slightly longer and carries a comparable volume of water. When combined with the lower Mississippi River, it forms the world's fourth-longest river system.

<span class="mw-page-title-main">Lake Itasca</span> Lake in Clearwater County, northern Minnesota, United States

Lake Itasca is a small glacial lake, approximately 1.8 square miles in area. It is located in Itasca State Park, in south-eastern Clearwater County, in the Headwaters area of north-central Minnesota, and is notable for being the headwater of the Mississippi River. It has an average depth of 20 to 35 feet and is 1,475 feet (450 m) above sea level.

<span class="mw-page-title-main">Current River (Ozarks)</span> River in the U.S. state of Missouri

The Current River forms in the southeastern portion of the Ozarks of Missouri and becomes a 7th order stream as it flows southeasterly out of the Ozarks into northeastern Arkansas where it becomes a tributary of the Black River, which is a tributary of the White River, a tributary of the Mississippi River. The Current River is approximately 184 miles (296 km) long and drains about 2,641 square miles (6,840 km2) of land mostly in Missouri and a small portion of land in northeastern Arkansas. The headwaters of the Current River are nearly 900 feet (270 m) above sea level, while the mouth of the river lies around 280 feet (85 m) above sea level. The basin drains a rural area that is dominated by karst topography, underlain by dolomite and sandstone bedrock with a small area of igneous rock southeast of Eminence, Missouri. The annual daily mean discharge of the river near Doniphan, Missouri is 2,815 cubic feet (79.7 m3) per second. In 1964, over 134 mi (160 km) of the upper course of the river and its tributaries were federally protected as the Ozark National Scenic Riverways, the first national park in America to protect a river system.

<span class="mw-page-title-main">Auglaize River</span> River in Ohio, United States

The Auglaize River is a 113-mile-long (182 km) tributary of the Maumee River in northwestern Ohio in the United States. It drains a primarily rural farming area in the watershed of Lake Erie. The name of the river was derived from the French term for it. The French called it "rivière à la Grande Glaize", referring to the soil in the area.

<span class="mw-page-title-main">Feather River</span> River in California, United States

The Feather River is the principal tributary of the Sacramento River, in the Sacramento Valley of Northern California. The river's main stem is about 73 miles (117 km) long. Its length to its most distant headwater tributary is just over 210 miles (340 km). The main stem Feather River begins in Lake Oroville, where its four long tributary forks join—the South Fork, Middle Fork, North Fork, and West Branch Feather Rivers. These and other tributaries drain part of the northern Sierra Nevada, and the extreme southern Cascades, as well as a small portion of the Sacramento Valley. The total drainage basin is about 6,200 square miles (16,000 km2), with approximately 3,604 square miles (9,330 km2) above Lake Oroville.

<span class="mw-page-title-main">Black River (Arkansas–Missouri)</span> River in Missouri, United States

The Black River is a tributary of the White River, about 300 miles (480 km) long, in southeastern Missouri and northeastern Arkansas in the United States. Via the White River, it is part of the Mississippi River watershed. Black River Technical College is named for the river.

<span class="mw-page-title-main">Big Muddy River</span> River in Southern Illinois

The Big Muddy River is a 156-mile-long (251 km) river in southern Illinois. It joins the Mississippi River just south of Grand Tower. The Big Muddy has been dammed near Benton, forming Rend Lake.

<span class="mw-page-title-main">Confluence</span> Meeting of two or more bodies of flowing water

In geography, a confluence occurs where two or more watercourses join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river ; or where two streams meet to become the source of a river of a new name ; or where two separated channels of a river rejoin at the downstream end.

<span class="mw-page-title-main">Perennial stream</span> Type of river

A perennial stream is a stream that has continuous flow of surface water throughout the year in at least parts of its catchment during seasons of normal rainfall, as opposed to one whose flow is intermittent. In the absence of irregular, prolonged or extreme drought, a perennial stream is a watercourse, or segment, element or emerging body of water which continually delivers groundwater. For example, an artificial disruption of stream, variability in flow or stream selection associated with the activity in hydropower installations, do not affect this status. Perennial streams do not include stagnant water, reservoirs, cutoff lakes and ponds that persist throughout the year. All other streams, or parts of them, should be considered seasonal rivers or lakes. The stream can cycle from intermittent to perpetual through multiple iterations.

<span class="mw-page-title-main">Red Rock River (Montana)</span> River in Montana, United States

The Red Rock River is a roughly 70-mile (110 km) river in southwestern Montana in the United States. Its drainage basin covers over 1,548 square miles (4,010 km2). Its furthest tributary, Hell Roaring Creek, originates in the Beaverhead National Forest within a few hundred meters of the North American Continental Divide and Montana-Idaho border near Brower's Spring, at an elevation of about 9,100 feet (2,800 m). Brower's Spring is near the furthest headwaters of the Missouri River, one of the major watercourses of the central United States. As such, it is also the furthest headwaters of the entire Missouri-Mississippi river system, today the fourth longest river on earth and once the third-longest.

The stream order or waterbody order is a positive whole number used in geomorphology and hydrology to indicate the level of branching in a river system.

<span class="mw-page-title-main">Stream</span> Body of surface water flowing down a channel

A stream is a continuous body of surface water flowing within the bed and banks of a channel. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long, large streams are usually called rivers, while smaller, less voluminous and more intermittent streams are known as streamlets, brooks or creeks.

<span class="mw-page-title-main">Satsop River</span> River in Washington, United States

The Satsop River is a stream in the U.S. state of Washington. It has three main tributary forks, the East Fork, West Fork, and Middle Fork Satsop Rivers. The main stem Satsop River is formed by the confluence of the West and East Forks. The Middle Fork is a tributary of the East Fork. The three forks are much longer than the main stem Satsop itself, which flows south from the confluence only a few miles to join the Chehalis River near Satsop, Washington. Other significant tributaries include the Canyon River and Little River, both tributaries of the West Fork Satsop, and Decker Creek, a tributary of the East Fork Satsop River. The Satsop River's major tributaries originate in the Olympic Mountains and its southern foothills, the Satsop Hills, within Grays Harbor and Mason counties. Most of the Satsop River's watershed consists of heavily wooded hill lands. The upper tributaries extend into Olympic National Forest, approaching but not quite reaching Olympic National Park.

The Ripple River is a small river of north-central Minnesota. The stream headwaters are at the outlet of Bay Lake of eastern Crow Wing County and it flows east and north to its confluence with the Mississippi River on the north side of Aitkin in Aitkin County. The river follows a circuitous route, with a total stream length of 42.3 miles (68.1 km); while the direct distance between its source and mouth is approximately 10 miles (16 km).

<span class="mw-page-title-main">Neepaulakating Creek</span> Tributary of Papakating Creek

Neepaulakating Creek is a 2.4-mile long (3.8 km) tributary of Papakating Creek in Wantage Township in Sussex County, New Jersey in the United States. It is one of three streams feeding the Papakating Creek, a major contributor to the Wallkill River. Although the stream was dammed in the 1950s to create Lake Neepaulin as the focal point of a private residential development, the stream did not receive a name until 2002. Residents chose a name that combined elements of the names "Neepaulin" and "Papakating", and submitted a proposal to the United States Board of Geographic Names. The name was approved in 2004.

Fox River is a stream in Davis, and Van Buren counties of Iowa, and Clark County of Missouri. It is a tributary of the Mississippi River.

Brush Creek is a stream in Crawford and Gasconade counties in the U.S. state of Missouri. It is a tributary to the Bourbeuse River.

Silver Creek is a stream in southwestern Randolph County and the southeast corner of Chariton County in north central Missouri. It is a tributary of the East Fork Little Chariton River with the confluence in Chariton County. The headwaters of Silver Creek are just northwest of Higbee.

References

  1. ↑ "Largest Rivers in the United States" (PDF). United States Geological Survey . Retrieved 24 October 2009.
  2. ↑ "National Geographic News @ nationalgeographic.com". news.nationalgeographic.com. Archived from the original on April 13, 2001.
  3. 1 2 "The True Utmost Reaches of the Missouri".
  4. ↑ "IBGE - Instituto Brasileiro de Geografia e Estatística". Archived from the original on 2011-06-15.
  5. ↑ Bailey, David (15 May 2012). "Could the River Thames be longer than the River Severn?". BBC News.
  6. ↑ "CERC Science Topic: Missouri River" (PDF). infolink.cr.usgs.gov.
  7. ↑ "Owens Valley Particulate Matter Plan: Q & A". Environmental Protection Agency . Retrieved 2008-05-30. ...the Owens River, the source of the lake...
  8. ↑ Jorge Enrique Casallas Guzmán (2004-02-11). "Limnological investigations in Lake San Pablo" (PDF). Archived from the original (PDF) on 2008-06-25. Retrieved 2008-05-30. ...source of the lake is the River Itambi...

Bibliography

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