Continental Divide

Home , Continental divide, Endorheic basin, Salt pan (geology)

R E S O U R C E L I B R A R Y E N C Y C L O P E D I C E N T RY Continental divide

A continental divide is an area of raised terrain that separates a continent’s river systems that feed to different basins.

G R A D E S 6 - 12+

S U B J E C T S Earth Science, Geography, Human Geography, Physical Geography

C O N T E N T S 5 Images

For the complete encyclopedic entry with media resources, visit: http://www.nationalgeographic.org/encyclopedia/continental-divide/ A continental divide is a naturally occurring boundary or ridge separating a continent’s river systems. Each river system feeds into a distinct ocean basin, bay, or sea.

Continental divides are broad, continent-wide example of drainage divides, sometimes just called divides. Divides are boundaries that separate drainage basins or watersheds of all sizes. Drainage divides, regardless of scale, occur in raised terrain such as mountain ranges or hills.

Generally, precipitation that falls on one side of the divide will flow to one basin and precipitation that falls on the other side will flow to another basin.

In some cases, water runs toward an endorheic basin, such as a saline lake or salt flat. Endorheic basins, which do not connect to an ocean or other large body of water, usually occur in desert areas. Much of the Sahara Desert in Africa, for example, is an endorheic basin. This means that rivers and streams that flow into Lake Chad, on the edge of the Sahara, have no outlet to either the Mediterranean Sea or the Atlantic or Indian Oceans.

/ Continental divides are found on every continent. Continents that are bordered by more than two bodies of water may have more than one continental divide. For example, North America has between three and five divides. Scientists have not yet agreed on a specific number because the exact border between ocean basins is not universally accepted.

Some continental divides span multiple continents. For example, the Continental Divide of the Americas, or the Great Divide, runs through much of North and South America. It separates the water that runs toward the Pacific Ocean from the water that runs toward the Atlantic and Arctic Oceans and the Gulf of Mexico. This divide runs from Cape Prince of Wales in western Alaska, through the Rocky Mountains of western Canada and the continental United States, then through the Sierra Madre Occidental mountains in Mexico, through Central America and along the Andes Mountains of South America. Vocabulary

Part of Term Definition Speech body of water partially surrounded by land, usually with a wide mouth bay noun to a larger body of water. boundary noun line separating geographical areas. continent noun one of the seven main land masses on Earth. continental point or area that separates which directions a continent's river systems noun divide flow. area of land that receives no more than 25 centimeters (10 inches) of desert noun precipitation a year. divide noun a ridge between two drainage systems. drainage an entire river system or an area drained by a river and its tributaries. noun basin Also called a watershed. endorheic noun watershed that empties into an internal body of water, not the ocean. basin continental divide in North America separating rivers that flow into the Great Divide noun Pacific Ocean and rivers that flow into the Atlantic Ocean. Also called the Continental Divide of the Americas. land that rises above its surroundings and has a rounded summit, usually hill noun less than 300 meters (1,000 feet). mountain noun series or chain of mountains that are close together. range ocean noun large body of salt water that covers most of the Earth. / Part of Term Definition Speech ocean basin noun depression in the Earth's surface located entirely beneath the ocean. precipitationnoun all forms in which water falls to Earth from the atmosphere. ridge noun long, narrow elevation of earth. river system noun tributaries, mouth, source, delta, and flood plain of a river. saline adjectivesalty. large, flat expanse of earth covered by a thick layer of salt left by an salt flat noun evaporated saline lake or pond. Also called a playa, sink, or salt pan. terrain noun topographic features of an area. watershed noun entire river system or an area drained by a river and its tributaries. Articles & Profiles GeoLounge: What is a Continental Divide?

Maps USGS: Continental Divide of the United States

Websites Continental Divide Trail Coalition