Triple divide

A triple divide or triple watershed is a point on Earth's surface where three drainage basins meet. A triple divide results from the intersection of three drainage divides. Triple divides range from prominent mountain peaks to minor side peaks, down to simple slope changes on a ridge which are otherwise unremarkable. The elevation of a triple divide can be thousands of meters to barely above sea level. Triple divides are a common hydrographic feature of any terrain that has rivers, streams and/or lakes.

Topographic triple divides do not necessarily respect the underground path of water. Thus, depending on the infiltration and the different geological layers, the hydrologic triple divide is often offset from the topographic triple divide.

A hydrological apex is a triple divide whose waters flow into three different oceans. Depending on definition, Triple Divide Peak in the U.S. state of Montana, or Snow Dome in Canada are the only such places on Earth.

Africa

An unnamed hill on the border between the Central African Republic and South Sudan: the exact point is at 09°08′24″N 23°28′07″E / 9.14000°N 23.46861°E / 9.14000; 23.46861 (Congo-Nile-Lake Chad Triple Divide). Water from this point flows to the Atlantic Ocean via the Congo River, to the Mediterranean Sea via the Nile, or to endorheic Lake Chad. At this point meet the second, third and eighth largest drainage basins in the world, making it one of the most important triple divides on earth.

Antarctica

Antarctica is completely encircled by the Southern Ocean, and has no triple divides.

Older definitions of the oceans did not include the Southern Ocean, and instead had the Atlantic, Pacific and Indian Oceans touch the shores of Antarctica. Based on this outdated definition, Dome Argus is the highest point in the East Antarctic ice sheet and could be considered a triple divide if it is assumed that the ice forms a watershed. (80°22′S 77°21′E / 80.367°S 77.350°E / -80.367; 77.350 (Dome Argus))

Asia

Asia features several endorheic basins. In Northeastern Mongolia, the endorheic basin meets the watersheds of the Selenga and the Amur, rivers that flow to the Arctic and the Pacific Ocean, respectively. In Tibet, the basin meets the watersheds of the Nu and the Yangtze, rivers that flow to the Indian and the Pacific Ocean, respectively.

Australia

Australia has two continental drainage divide tripoints, close to each other along Queensland's Great Dividing Range. Both are named after two 1845 exploration party leaders who sought to solve the question of Australia's rivers: Thomas Mitchell and Edmund Kennedy.

• Mitchell Junction is in North Queensland, on Triple C Pastoral Station, near the White Mountains National Park. Water falling on the tripoint can flow either to
  • the Pacific Ocean via the Burdekin River,
  • to the Indian Ocean, via the Flinders River flowing to the Gulf of Carpentaria and the Indonesian Throughflow,
  • and lastly to Lake Eyre via Cooper Creek. approximately 20°20′58″S 145°03′17″E / 20.349540608585798°S 145.05459085035665°E / -20.349540608585798; 145.05459085035665 (Mitchell Junction)
• Kennedy Junction is in Central Queensland, on Caldervale Station, near Carnarvon National Park. Water falling on the tripoint can flow either
  • to the Pacific Ocean via the Fitzroy River,
  • to the Southern Ocean, via Murray/Darling River, and
  • to Lake Eyre via Cooper Creek. 24°55′22″S 146°49′27″E / 24.9227°S 146.8241°E / -24.9227; 146.8241 (Kennedy Junction)

Europe

North America

North America has three triple divides in the United States which are intersections of continental divides, and a fourth one in Canada. Waters at these triple divides flow into three different oceans, seas or gulfs. Triple Divide Peak in Montana is considered the triple divide "hydrological apex" of North America, though Snow Dome on the Alberta-British Columbia border also has a claim depending on how the Arctic and Atlantic Oceans are defined. North America is the only continent that has a triple point dividing basins draining into three different oceans. Where the Continental Divide splits and joins to form the boundary of the Great Divide Basin, it forms two triple points.

Other points are often considered to be triple divides because they separate basins of continental rivers.

• Headwaters Hill in Saguache County, Colorado, near Chester (Arkansas River, Rio Grande River, Colorado River). This point has only a weak claim to being a continental triple divide because both the Rio Grande and Arkansas Rivers flow into the Gulf of Mexico. (38°20′52″N 106°15′11″W / 38.3477709°N 106.2530695°W / 38.3477709; -106.2530695 (Headwaters Hill))

The highest elevation (4,040 m or 13,240 ft) significant triple divide in the lower 48 states of the United States, in Kings Canyon National Park in Fresno/Inyo counties, California, is a sub-peak of Mount Wallace of the central Sierra Nevada:

• Crumbly Spire or Mount Wallace South Peak, Fresno/Inyo counties, California (Tulare Lake via Kings River, Owens Lake via Owens River, Pacific Ocean via San Joaquin River) (37°08′28″N 118°39′15″W / 37.141188°N 118.654119°W / 37.141188; -118.654119 (Crumbly Spire))

Numerous other triple divide points result from intersection of river basin divides, including:

• Young Lick Knob, Georgia (Savannah, Apalachicola, Mississippi) (34°49′22″N 83°39′09″W / 34.82278°N 83.65250°W / 34.82278; -83.65250 (Young Lick Knob))

South America

There are no triple points in South America where the divide splits.

See also

• Continental divide

Notes

References

Citations

• Joseph A. DiPietro (2012-12-21). Landscape Evolution in the United States: An Introduction to the Geography, Geology, and Natural History. Newnes.