Continental divide

Categories: Landforms

This article is about continental divides in general terms. For the Atlantic/Pacific divide, see Continental Divide. Continental Divide is also the title of a 1981 movie starring John Belushi and Blair Brown.

A continental divide is a line of elevated terrain which forms a border between two watersheds such that water falling on one side of the line eventually travels to one ocean or body of water, and water on the other side travels to another, generally on the opposite side of the continent. Because the exact border between bodies of water is usually not clearly defined, the continental divide is not always definite for any continent (The International Hydrographic Organization's publication Limits of Oceans and Seas defines exact boundaries of oceans, but it is not universally recognized). Moreover, some rivers empty into deserts or inland seas, and thus do not end up in the oceans.

Examples

• North America has a four continental divides:
  • The Great Divide, also called the Continental Divide separates the watersheds of the Pacific Ocean from those of the Atlantic or Arctic Oceans. It runs from the Seward Peninsula in Alaska, through western Canada along the crest of the Rocky Mountains to New Mexico. From there, it follows the crest of Mexico's Sierra Madre Oriental and extends to the tip of South America. It is crossed by the Panama Canal
  • the Northern Divide separates the watershed of the Atlantic Ocean from that of the Arctic Ocean
  • The St. Lawrence Seaway Divide separates the Great Lakes watershed from the rest of the Atlantic Ocean watershed. Two canals cross the divide: The Chicago Sanitary and Ship Canal crosses the Chicago Portage and connects Lake Michigan to the Mississippi River watershed. The Erie Canal connects Lake Erie to the Hudson River watershed.
  • The Eastern Continental Divide separates the watershed of the Gulf of Mexico from the Atlantic Ocean. It runs from northern Pennsylvania down the Appalachian Mountains to the tip of Florida, dividing the Atlantic from the Gulf of Mexico. The city of Atlanta sits atop this divide.
• In South America, the Continental Divide lies along the Andes, but, contrary to logic, the divide does not run along the highest peaks of the mountain system.
• Australia has less distinct ocean boundaries and fewer prominent mountain ranges, making it hard to define a single divide.
• It is similarly difficult to distinguish the continental divides of Europe and Asia, because of the large number of distinct bodies of water into which their rainfall drains (for example, the Mediterranean Sea and its various lobes, the Atlantic Ocean, the North Sea, the Baltic Sea, the Arctic Ocean and the Black Sea with Europe).

Every continent except for Antarctica has a continental divide.

See also

• Watershed

External links

• Continental Divide Trail Alliance
• nationalatlas.gov
• Divide.pdf - Continental Divides in North Dakota and North America by Mark A. Gonzalez. Excellent article on America's other continental divides.
• Map of drainage basins in Canada