Whoops. Sorry about the nature posts. Must be the time of the year. And the fact that Discovery is on a lot. Because i love scientific stuff. One of these questions I’d always like to know is, where does a stream begin. How far do you need to go before you can call it the origin.
Top Gear did it with the Nile. An was in the end correct. Unfortunately, as you can read further ahead, the right answer is not always the correct answer. But it makes up for a nice read.
The Mississippi River is the chief river of the largest drainage system in North America, rising in northern Minnesota and flowing for 3,770 km (2,340 mi) into the Gulf of Mexico.
With its many tributaries, the Mississippi’s watershed drains all or parts of 31 U.S. states and 2 Canadian provinces. Shown here flowing near the city of New Orleans.
The “source” or “headwaters” of a river is an elusive concept. On a colloquial basis, some define the source of a river at the lake from which the river flows. The source of the Upper Mississippi branch of the Mississippi River is traditionally accepted as Lake Itasca in Itasca State Park in Clearwater County, Minnesota. The name “Itasca” was chosen to designate the “true head” of the Mississippi River as a combination of the last four letters of the Latin word for truth (veritas) and the first two letters of the Latin word for head (caput). However, the lake is in turn fed by a number of smaller streams.
The Nile (seen here flowing through Cairo) is generally regarded as the longest river in the world at 6,853 km (4,258 mi) long, and its water resources are shared by Tanzania, Uganda, Rwanda, Burundi, Democratic Republic of the Congo, Kenya, Ethiopia, Eritrea, South Sudan, Sudan and Egypt. The Nile has two major tributaries, the White Nile, which is considered the headwaters and primary stream, and the Blue Nile, which is the source of most of the water and fertile soil. The two rivers meet near the Sudanese capital of Khartoum.
Defining the source of a river by its outflow from a lake can significantly shorten the river’s distance. National Geographic and virtually every other geographic authority and atlas define the source of the Nile not as Lake Victoria’s outlet where the name “Nile” first appears, which would reduce the Nile’s length by over 900 km (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. Sources do not agree on which is the longest tributary of the Kagera and hence the most distant source of the Nile itself. It is either the Ruvyironza or the Nyabarongo. Pictured here is only one of the candidates for the “ultimate” source of the Nile, the alleged source of the Nyabarongo in the Nyungwe Forest in Rwanda.
The Blue Nile has a total length of 1,450 km (900 mi), and flows generally south from Lake Tana. Although there are several feeder streams that flow into Lake Tana, the sacred source of the river is generally considered to be a small spring at Gish Abbai, situated at an altitude of approximately 2,744 m (9,003 ft).
The Columbia River is the largest river in the Pacific Northwest region of North America. The river is 2,000 km (1,243 mi) long and flows through the Province of British Columbia and the States of Washington (pictured here) and Oregon. By volume, the Columbia is the fourth-largest river in the United States; it has the greatest flow of any North American river draining into the Pacific. The river’s heavy flow and its relatively steep gradient give it tremendous potential for the generation of electricity.
This most common definition of a river source specifically uses the most distant point along watercourses from the river mouth from which water runs year-round (perennially). The Columbia begins its journey in the southern Rocky Mountain Trench in British Columbia, bubbling out of deep springs in the town of Canal Flats. Columbia Lake, and the adjoining Columbia Wetlands form the river’s headwaters.
The 2,525 km (1,569 mi) Ganges River rises in the western Himalayas, and flows through the Gangetic Plain of North India (pictured here passing through Kolkata) into Bangladesh, where it empties into the Bay of Bengal. It is the third largest river by discharge. The Ganges is the most sacred river to Hindu, and is also a lifeline to millions of Indians who live along its course and depend on it for their daily needs. It is worshipped as the goddess Ganga in Hinduism. The Ganges was ranked as the fifth most polluted river of the world in 2007, but the Ganga Action Plan, an environmental initiative to clean up the river, has been a major failure thus far.
The Ganges begins at the confluence of the Bhagirathi and Alaknanda rivers at Devprayag. The Bhagirathi is considered to be the true source in Hindu culture and mythology, although the Alaknanda is longer. The Bhagirathi rises at the foot of Gangotri Glacier, one of the largest glaciers in the Himalayas at over 27 cubic kilometers, at an elevation of 3,892 m (12,769 ft). Gomukh, which is name of the mouth of the glacier from which the Bhagirathi rises, is a popular Hindu pilgrimage site, whose name literally means “Mouth of a Cow”.
The River Thames flows through southern England, and at 346 km (215 mi) is the longest river entirely in England and the second longest in the United Kingdom. The Thames (pictured here flowing through London) has been used during two Summer Olympic Games: 1908 (rowing) and 1948 (rowing and canoeing).
The source of a river may also be defined as the furthest point from which water could possibly flow (ephemerally), rather than from which water runs year-round. Thames Head is a site in Gloucestershire, traditionally identified as the source of the River Thames. A nearby basin of stones marks the spring; however, there is usually only water during a wet winter. The claim that Thames Head is the source of the River Thames is disputed. Some authorities hold that the true source of the Thames is at Seven Springs, Gloucestershire. Officially, however, Seven Springs is the source of the River Churn, a tributary of the Thames.
The Danube is a river in Central and Eastern Europe that empties into the Black Sea. At 2,872 km (1,785 mi), it is the European Union’s longest and the continent’s second longest river. Once a long-standing frontier of the Roman Empire, the river passes through or touches the borders of ten countries: Romania, Hungary, Serbia, Austria, Germany, Bulgaria, Slovakia, Croatia, Ukraine, and Moldova; and flows through four European capitals: Vienna, Bratislava, Budapest (pictured here) and Belgrade.
Another traditional way to measure the source of a river is at a confluence of two rivers where the river’s name is first used. Most sources indicate that the Danube starts at Donaueschingen in Germany at the confluence of the rivers Brigach and Breg. However, Breg itself can be traced to a tiny rivulet seeping out of the rocks at the top end of a wide bottomed valley (pictured here).
Regarded as the second-longest river in the world at 6,400 km (4,000 mi), the Amazon has the world’s largest drainage basin, which covers the countries of Brazil, Peru, Bolivia, Colombia, Ecuador, Venezuela, and Guyana and accounts for approximately one-fifth of the world’s total river flow.
Glacial headwaters are relatively common. The most distant source of the Amazon was established as a glacial stream on a snowcapped 5,597 m (18,363 ft) peak called Nevado Mismi in the Peruvian Andes, and is now marked only by a wooden cross.
The Zambezi (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, and the largest flowing into the Indian Ocean from Africa. The 2,574km (1,599 mi) river rises in Zambia and flows through eastern Angola, along the eastern border of Namibia and the northern border of Botswana, then along the border between Zambia and Zimbabwe to Mozambique, where it crosses that country to empty into the Indian Ocean. The Zambezi’s most noted feature is Victoria Falls.
Sometimes the source of the most remote tributary may be in an area that is more marsh-like, in which case the “uppermost” or most remote section of the marsh would be the true source. The Zambezi rises in a black marshy dambo in north-west Zambia, in dense undulating miombo woodland.
The Rhine is a European river that begins in the southeastern Swiss Alps, forms part of the Swiss-Austrian, Swiss- Liechtenstein border, Swiss-German and then the Franco-German border, then flows through the Rhineland (pictured here passing through Cologne, Germany) and eventually empties into the North Sea in the Netherlands. It is the second longest river in Central and Western Europe at about 1,230 km (760 mi). It has become a symbol of German Romantic nationalism.
Headwaters are the most extreme upstream areas of a watershed, and the river source is often but not always on or quite near the edge of the watershed, or watershed divide. The Rhine’s and Danube’s watersheds are so close, that the two rivers are continuously jostling for streams in their upper regions. Lake Toma in the Swiss Canton of Graubünden is generally regarded as the source of the Rhine. Its outflow (pictured here) is called Rein da Tuma and after a few kilometers, it forms the Vorderrhein. The longest headwater of both the Vorderrhein and the Rhine as a whole; however, is the Reno di Medel, rising about 7.5 km south of Lake Toma. Its spring and upper reaches are located West of the Lukmanier Pass in the municipality of Quinto in Ticino.
The Yangtze is the longest river in Asia and the third-longest in the world at 6,300 km (3,915 mi). The river is the longest in the world to flow entirely within one country and shown here flowing through Anqing Anhui, China. The Yangtze River is a habitat to several endemic and endangered species including the Chinese alligator, the finless porpoise, the Chinese paddlefish, the possibly extinct Yangtze River dolphin or baiji, and the Yangtze sturgeon.
There are a number of candidates that may be considered to be the source of the Yangtze, this glacier lying on the west of Geladandong Mountain in the Tanggula Mountains Range on the eastern part of the Qinghai-Tibet Plateau being one of them.
The Volga River (shown here flowing through Saratov) is the longest river in Europe at 3,692 km (2,294 mi), and also the largest in terms of discharge and watershed. It flows through central Russia and is widely viewed as the national river of Russia, having a symbolic meaning in Russian culture and often being referred to as Волга-матушка Volga-Matushka (Mother Volga) in Russian literature and folklore.
The source of the Volga is located in the Valdai Hills northwest of Moscow and about 320 kilometers (200 mi) southeast of Saint Petersburg, in the village of Volgoverkhovye about 68 km from Ostashkov town.
The Yellow River or Huang He (pictured flowing through Luoyang, Henan, China) is the third-longest river in Asia and the sixth-longest in the world at the estimated length of 5,464 km (3,395 mi). The Yellow River is called “the cradle of Chinese civilization”, because its basin was the birthplace of ancient Chinese civilization, and it was the most prosperous region in early Chinese history. However, frequent devastating floods and course changes have also earned it the names China’s Sorrow and Scourge of the Sons of Han.
According to the China Exploration and Research Society, the source of the Yellow River is in the Bayan Har Mountains near the eastern edge of the Yushu Tibetan Autonomous Prefecture, a spot that is marked by a tablet.
The Don is one of the major rivers of Russia, and flows for a distance of about 1,950 kilometres (1,220 mi) to the Sea of Azov. The major city on the river is Rostov on Don, pictured here. In antiquity, the river was viewed as the border between Europe and Asia by some ancient Greek geographers.
The Don rises in the town of Novomoskovsk 60 kilometres southeast of Tula, which itself is southeast of Moscow.
The Ural, known as Yaik before 1775, is a river flowing through Russia and Kazakhstan (pictured here passing through the city of Atyrau, Kazakhstan) and ending at the Caspian Sea. Its total length is 2,428 km (1,509 mi), making it the third longest river in Europe. The entire length of the Ural River is considered the Europe-Asia boundary by most authoritative sources.
The Ural River begins at the slopes of the Kruglaya Mountain of the Uraltau mountain ridge in South Ural, on the territory of the Uchalinsky District of Bashkortostan, Russia.
The Po flows 652 km (405 mi) eastward across northern Italy through a delta projecting into the Adriatic Sea near Venice. The river flows through many important Italian cities (pictured here passing through Cremona), including Turin (Torino), Piacenza and Ferrara. It is connected to Milan through a net of channels called navigli, which Leonardo da Vinci helped design. The river is subject to heavy flooding and over half its length is controlled with argini, or dikes.
The Po originates from a spring seeping from a stony hillside at Pian del Re, a flat place at the head of the Val Po under the northwest face of Monviso in the Cottian Alps.