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.
Course
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At its northern terminus, the Eastern Continental Divide originates at the Eastern Triple Divide[a], its intersection with the St. Lawrence Divide on a summit named Triple Divide Peak in Potter County, Pennsylvania, about 10 mi (16 km) south of the New York-Pennsylvania border. This point divides the eastern United States into three watersheds, those of the St. Lawrence River to the north, the Atlantic seaboard to the east, and the Gulf of Mexico to the west.
From north to south, the divide passes through the broader Allegheny Plateau region, following the boundary between the Allegheny River and Susquehanna River watersheds through most of Pennsylvania. At Blue Knob near Altoona, the Divide begins to follow Allegheny Mountain and then Little Savage Mountain. A few miles before the state border, the Divide begins to separate the Youghiogheny River and Potomac River watersheds.[2]
In Maryland, the Divide runs significantly west of the Allegheny Front, following Backbone Mountain, and passing near the source of the North Branch Potomac River at the Fairfax Stone. The Divide then passes through a plateau of the Allegheny Mountains of West Virginia, passing between the north end of the Canaan Valley in the Cheat River watershed, and the Mount Storm Lake basin in the Potomac River watershed. The Divide then rejoins the Allegheny Front.
A significant portion of the Divide forms part of the border between West Virginia and Virginia along Allegheny Mountain and then Peters Mountain, separating the Greenbrier River and James River watersheds. It then makes a dramatic arc to the east around the Sinking Creek valley, and then follows the hill crest east of Blacksburg, Virginia, until it meets the Blue Ridge Mountains, which take the form of an escarpment separating the headwaters of the New River from that of the Roanoke River.[3][4]
Just before the Divide passes into North Carolina, it begins to separate the New River and Yadkin River watersheds. It then separates upper tributaries of the Tennessee River from those of the Santee River.[5] Its high point is on Grandfather Mountain at 5,946 feet (1,812 m); although Mount Mitchell is the highest point in the Appalachian Mountains, it is not on the Divide, but 4 miles west of it.
In Georgia, the Divide generally separates the Apalachicola River watershed in the west from the Savannah River and Altamaha River watersheds to the east, passing through the Atlanta metropolitan area and extending past the southern end of the Appalachian Mountains southeasterly across the Georgia plateau. This marks the first time the western watershed drains directly to the Gulf of Mexico without reaching the Ohio River first. In southern Georgia, it separates the Suwannee River and Satilla River watersheds.[6]
In Florida, the Divide generally follows the western edge of the St. Johns River, meandering into the low country of Northern Florida until it reaches central Florida. The southern terminus of the Eastern Continental Divide is at the northern edge of the Kissimmee River watershed, part of the Lake Okeechobee drainage basin.[b]. The elevation here is about 70 ft (21 m).
South of here, the terrain consists of low swampland covered by a network of diverging canals and natural waterways. As such, the land is not clearly divisible between the Gulf of Mexico watershed and the Atlantic watershed.[citation needed]
The exact route of the ECD shifts over time due to erosion, tectonic activity, construction projects, and other factors.
Weather
editBecause the divide is at or in proximity to the highest terrain, air is forced upwards regardless of wind direction. This process of orographic enhancement leads to higher precipitation than surrounding areas. In winter, the divide is often much snowier than surrounding areas, due to orographic enhancement and cooler temperatures with elevation.
History
editPrior to about 1760, north of Spanish Florida, the Appalachian Divide represented the boundary between British and French colonial possessions in North America. [8] The Royal Proclamation of 1763 separated settled lands of the Thirteen Colonies from lands north and west of it designated the Indian Reserve; the proclamation border ran along the Appalachian Divide but extended beyond its Pennsylvania-New York terminus north into New England.
Locations
editSee also
editNotes
edit- ^ @41°50′48″N 77°50′14″W / 41.84667°N 77.83722°W, elevation: 2,507 feet (764 m)[1]
- ^ The headwaters of Boggy Creek just southwest of Orlando International Airport including Mud Lake @28°23′24″N 81°17′30″W / 28.39000°N 81.29167°W and Marie Prairie @28°24′51″N 81°18′07″W / 28.41417°N 81.30194°W[7]
References
edit- ^ "Triple Divide". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
- ^ "PENNSYLVANIA'S MAJOR RIVER BASINS" (PDF). PA Department of Conservation and Natural Resources. Archived from the original (PDF) on 2021-09-01. Retrieved 2021-09-01.
- ^ "Major River Watersheds of the Chesapeake Bay". www.cbf.org. Retrieved 2021-09-01.
- ^ "Virginia's Major Watersheds". www.dcr.virginia.gov. Retrieved 2021-09-01.
- ^ "North Carolina Watersheds". www.carolana.com. Retrieved 2021-09-01.
- ^ "Georgia Rivers". Georgia River Network. Retrieved 2021-09-01.
- ^ GNIS
- ^ Alvin M. Josephy, Jr., ed. (1961). The American Heritage Book of Indians. The editors of American Heritage Magazine. American Heritage Publishing Co., Inc. LCCN 61-14871., pages 180-211, 188-189
- ^ "Elevation Chart". The Great Allegheny Passage: The Cumberland and Pittsburgh Trail. Allegheny Trail Alliance. Archived from the original on May 6, 2009. Retrieved 2009-11-09. Maps: Eastern Continental Divide Archived 2010-05-15 at the Wayback Machine
- ^ "Rock Mountain, GA - N34.91472° W83.34389°". www.topoquest.com.