Watersheds of North America

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A map of watersheds separated by the principal hydrological divides of North America NorthAmerica-WaterDivides.png
A map of watersheds separated by the principal hydrological divides of North America

Watersheds of North America are large drainage basins which drain to separate oceans, seas, gulfs, or endorheic basins. There are six generally recognized hydrological continental divides which divide the continent into seven principal drainage basins spanning three oceans (Arctic, Atlantic and Pacific) and one endorheic basin. The basins are the Atlantic Seaboard basin, the Gulf of Mexico basin, the Great Lakes-St. Lawrence basin, the Pacific basin, the Arctic basin, the Hudson Bay basin, and the Great Basin. Together, the principal basins span the continent with the exception of numerous smaller endorheic basins.

Contents

The Atlantic Seaboard basin in eastern North America drains to the Atlantic Ocean; the Great Lakes-St. Lawrence basin in central and eastern North America drains to the Gulf of St. Lawrence on the Atlantic Ocean or to the Labrador Sea; the Gulf of Mexico basin in the southern United States drains to the Gulf of Mexico, a basin of the Atlantic Ocean; the Pacific basin in western North America drains to the Pacific Ocean or the Gulf of California on the Pacific Ocean; the Arctic basin in northwestern North America drains to the Beaufort Sea of the Arctic Ocean or directly to the Arctic Ocean; the Hudson Bay basin in central northern North America drains to Hudson Bay on the Labrador Sea (which may be considered part of either the Arctic Ocean or Atlantic Ocean), or to the Arctic Sea via Foxe Basin and Fury and Hecla Strait; the Great Basin in western United States is an endorheic basin which does not drain to any ocean.

The Atlantic Seaboard basin is bounded by the Atlantic Ocean to the east, the Eastern Continental Divide to the west, the Great Lakes-St. Lawrence Divide to the north, and the Lake Okeechobee endorheic basin to the south. The Gulf of Mexico basin is bounded by the Gulf of Mexico to the south, the Eastern Continental Divide to the east, the Great Lakes-St. Lawrence Divide to the northeast, the Laurentian Divide to the North, and the Continental Divide to the west. The Pacific Basin is bounded by the Continental divide to the east and Pacific Ocean to the west; the basin excludes the endorheic Great Basin in the west. The Great Basin has a closed loop boundary encompassing substantially all of Nevada, the western half of Utah and parts of Oregon, California, Idaho, and Wyoming.

Endorheic basins

Most lakes are not actually endorheic, but endorheic basins may not have standing water, or have water only seasonally. The most significant endorheic basins are these:

Boundary landforms

The western boundary (Eastern Continental Divide) of the Atlantic Seaboard basin and eastern boundary of the Gulf of Mexico basin is formed by the Appalachian Mountains to the North, the Piedmont Plateau and lowland ridges of the Atlantic Coastal plain to the south. The eastern boundary of the Pacific basin and western boundary of the Gulf of Mexico basin (Continental Divide) is the Rocky Mountains.

Principal rivers of basins

A principal river of a basin is a river that drains directly to the incident ocean, sea or gulf, or into an endorheic basin.

Great Lakes-St. Lawrence basin

Atlantic Seaboard basin

Gulf of Mexico basin

Arctic basin

Hudson Bay basin

Pacific basin

Great Basin

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<span class="mw-page-title-main">Geography of Canada</span>

Canada has a vast geography that occupies much of the continent of North America, sharing a land border with the contiguous United States to the south and the U.S. state of Alaska to the northwest. Canada stretches from the Atlantic Ocean in the east to the Pacific Ocean in the west; to the north lies the Arctic Ocean. Greenland is to the northeast with a shared border on Hans Island. To the southeast Canada shares a maritime boundary with France's overseas collectivity of Saint Pierre and Miquelon, the last vestige of New France. By total area, Canada is the second-largest country in the world, after Russia. By land area alone, however, Canada ranks fourth, the difference being due to it having the world's largest proportion of fresh water lakes. Of Canada's thirteen provinces and territories, only two are landlocked while the other eleven all directly border one of three oceans.

<span class="mw-page-title-main">Continental Divide of the Americas</span> Principal hydrological divide of North and South America

The Continental Divide of the Americas is the principal, and largely mountainous, hydrological divide of the Americas. The Continental Divide extends from the Bering Strait to the Strait of Magellan, and separates the watersheds that drain into the Pacific Ocean from those river systems that drain into the Atlantic and Arctic Ocean, including those that drain into the Gulf of Mexico, the Caribbean Sea, and Hudson Bay.

<span class="mw-page-title-main">Drainage basin</span> Land area where water converges to a common outlet

A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide, made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern.

<span class="mw-page-title-main">Endorheic basin</span> Closed drainage basin that has no outflow

An endorheic basin is a drainage basin that normally retains water and allows no outflow to other, external bodies of water ; instead, the water drainage flows into permanent and seasonal lakes and swamps that equilibrate through evaporation. Endorheic basins are also called closed basins, terminal basins, and internal drainage systems.

<span class="mw-page-title-main">Atlantic seaboard watershed</span>

The Atlantic seaboard watershed is a watershed of the Atlantic Ocean in eastern North America along the Atlantic Canada (Maritimes) coast south of the Gulf of Saint Lawrence Watershed, and the East Coast of the United States north of the Kissimmee River watershed of Lake Okeechobee basin in the central Florida Peninsula.

<span class="mw-page-title-main">Eastern Continental Divide</span> Hydrological divide in eastern North America

The Eastern Continental Divide, Eastern Divide or Appalachian Divide is a hydrological divide in eastern North America that separates the easterly Atlantic Seaboard watershed from the westerly Gulf of Mexico watershed. The divide nearly spans the United States from south of Lake Ontario through the Florida peninsula, and consists of raised terrain including the Appalachian Mountains to the north, the southern Piedmont Plateau and lowland ridges in the Atlantic Coastal Plain to the south. Water including rainfall and snowfall, lakes, streams and rivers on the eastern/southern side of the divide drains to the Atlantic Ocean; water on the western/northern side of the divide drains to the Gulf of Mexico. The ECD is one of six continental hydrological divides of North America which define several drainage basins, each of which drains to a particular body of water.

<span class="mw-page-title-main">Great Divide Basin</span> Endorheic basin adjoining the Continental Divide in southern Wyoming, USA

The Great Divide Basin or Great Divide Closed Basin is an area of land in the Red Desert of Wyoming where none of the water falling as rain to the ground drains into any ocean, directly or indirectly. It is thus an endorheic basin, one of several in North America that adjoin the Continental Divide. To the south and west of the basin is the Green River watershed, draining to the Gulf of California/Pacific Ocean; to the north and east is the North Platte watershed, draining to the Gulf of Mexico. The basin is very roughly rectangular in shape; the northwest corner is at Oregon Buttes near South Pass, about 40 miles (64 km) southwest of Lander, and the southeast corner is in the Sierra Madre Range near Bridger Pass, about 20 miles (32 km) southwest of Rawlins.

<span class="mw-page-title-main">Triple Divide Peak (Montana)</span> Mountain in Montana, United States. Located at the hydrological apex of North America.

Triple Divide Peak is located in the Lewis Range, part of the Rocky Mountains in North America. The peak is a feature of Glacier National Park in the state of Montana in the United States. The summit of the peak, the hydrological apex of the North American continent, is the point where two of the principal continental divides in North America converge, the Continental Divide of the Americas and the Northern or Laurentian Divide.

<span class="mw-page-title-main">Hudson Bay drainage basin</span> Major drainage basin in Canada and the United States

The Hudson Bay drainage basin is the drainage basin in northern North America where surface water empties into the Hudson Bay and adjoining waters. Spanning an area of about 3,861,400 square kilometres (1,490,900 sq mi) and with a mean discharge of about 30,900 m3/s (1,090,000 cu ft/s), the basin is almost entirely within Canada. It encompasses parts of the Canadian Prairies, Central Canada, and Northern Canada. A small area of the basin is in the northern part of the Midwestern United States.

<span class="mw-page-title-main">Geography of North America</span> Overview of the geography of North America

North America is the third largest continent, and is also a portion of the third largest supercontinent if North and South America are combined into the Americas and Africa, Europe, and Asia are considered to be part of one supercontinent called Afro-Eurasia. With an estimated population of 580 million and an area of 24,709,000 km2 (9,540,000 mi2), the northernmost of the two continents of the Western Hemisphere is bounded by the Pacific Ocean on the west; the Atlantic Ocean on the east; the Caribbean Sea on the south; and the Arctic Ocean on the north.

<span class="mw-page-title-main">Laurentian Divide</span> Hydrological divide in North America

The Laurentian Divide also called the Northern Divide and locally the height of land, is a continental divide in central North America that separates the Hudson Bay watershed to the north from the Gulf of Mexico watershed to the south and the Great Lakes-St. Lawrence watershed to the southeast.

<span class="mw-page-title-main">Continental divide</span> Drainage divide on a continent

A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not connected to the open sea. Every continent on earth except Antarctica has at least one continental drainage divide; islands, even small ones like Killiniq Island on the Labrador Sea in Canada, may also host part of a continental divide or have their own island-spanning divide. The endpoints of a continental divide may be coastlines of gulfs, seas or oceans, the boundary of an endorheic basin, or another continental divide. One case, the Great Basin Divide, is a closed loop around an endorheic basin. The endpoints where a continental divide meets the coast are not always definite since the exact border between adjacent bodies of water is usually not clearly defined. The International Hydrographic Organization's publication Limits of Oceans and Seas defines exact boundaries of oceans, but it is not universally recognized. Where a continental divide meets an endorheic basin, such as the Great Divide Basin of Wyoming, the continental divide splits and encircles the basin. Where two divides intersect, they form a triple divide, or a tripoint, a junction where three watersheds meet.

A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or is unconnected. Continental divide may also refer to:

<span class="mw-page-title-main">Lake bifurcation</span> Lake that flows into two drainage basins

A lake bifurcation occurs when a lake has outflows into two different drainage basins. In this case, the drainage divide cannot be defined exactly, as it is situated in the middle of the lake.

<span class="mw-page-title-main">Triple divide</span> Point where three drainage basins meet

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 two 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.

<span class="mw-page-title-main">St. Lawrence River Divide</span> Hydrological divide in eastern North America

The Saint Lawrence River Divide is a continental divide in central and eastern North America that separates the Great Lakes-St. Lawrence River Basin from the southerly Atlantic Ocean watersheds. Water, including rainfall and snowfall, lakes, rivers and streams, north and west of the divide, drains into the Gulf of St. Lawrence or the Labrador Sea; water south and east of the divide drains into the Atlantic Ocean or Gulf of Mexico. The divide is one of six continental divides in North America that demarcate several watersheds that flow to different gulfs, seas or oceans.

Wood Mountain Hills are a hilly plateau in the Canadian province of Saskatchewan. The hills are located in the southern part of the province and are part of the Missouri Coteau, which is part of the Laurentian Divide between the watersheds of the Hudson Bay drainage basin of the Arctic Ocean and the Gulf of Mexico of the Atlantic Ocean. The hills are in a semi-arid region known as Palliser's Triangle in the Great Plains ecoregion of North America.

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