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.
The Eastern Triple Divide [lower-alpha 1] is the northern terminus of the Eastern Continental Divide where it intersects the northeasterly St. Lawrence Divide near the middle of the northern border of Pennsylvania. That point divides the eastern United States into three watersheds, where the associated nearby headwaters form the Pine Creek tributary of the West Branch Susquehanna River that drains to the Atlantic ocean, the Allegheny River tributary of the Ohio River that drains to the Gulf of Mexico, and the Genesee River tributary of Lake Ontario that drains to the Gulf of Saint Lawrence.
The Eastern Continental Divide originates in the north at the Eastern Triple Divide in north-central Pennsylvania on the summit named 'Triple Divide Peak', 10.4 mi (16.7 km) south of the New York-Pennsylvania line, about 5 mi. southwest of the borough of Ulysses in Potter County, Pennsylvania. 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 6,366 ft (1,940 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]
The Lake Okeechobee drainage basin in south-central Florida, including the Kissimmee River drainage basin to the north which feeds it, was naturally or hydrographically, an endorheic basin, one which does not have outflow to another body of water like a river or ocean. Such a basin may form a swamp when water collects. It was altered by anthropogenic activity, specifically the construction of the Okeechobee canal in 1937 which spanned the Atlantic Ocean, the lake, and the Gulf of Mexico. Nonetheless, it is not considered by hydrologists to be part of either the Gulf of Mexico watershed or the Atlantic seaboard watershed. The northern boundary of the basin [lower-alpha 2] is the southern terminus of the Eastern Continental divide.
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, ending at the north bank watershed of the Kissimmee River at the northern boundary of the Lake Okeechobee Basin(see sidebar). While notionally, the ECD may be considered to extend to the southern tip of Florida, south of Lake Okeechobee the Everglades, which spans the length and breadth of the peninsula, is a seasonal swamp which drains into an unchannelled "river" 100 miles long and 60 miles wide that flows south to the Gulf of Mexico.
Though the divide is often associated with high elevation, at its southern terminus at the northern Kissimmee River watershed in Florida, the elevation is only 70 ft (21 m) above sea level. [8] Nor does the divide always coincide with the highest point or ridgeline, because streams can flow through passes or gaps in the ridge, so that terrain on one side of the ridge drains to the other side and therefore to the other watershed. This occurs in several places. The ECD is not completely fixed but can shift due to erosion, tectonic shift, and also anthropogenic activity such as tunnel excavation, damming of rivers, and road construction.
Because 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.
Prior to about 1760, north of Spanish Florida, the Appalachian Divide represented the boundary between British and French colonial possessions in North America. [9] 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.
Divides
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.
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.
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.
The Apalachicola River is a river, approximately 160 miles (260 km) long, in the state of Florida. The river's large watershed, known as the Apalachicola, Chattahoochee and Flint (ACF) River Basin, drains an area of approximately 19,500 square miles (50,500 km2) into the Gulf of Mexico. The distance to its farthest head waters in northeast Georgia is approximately 500 miles (800 km). Its name comes from Apalachicola Province, an association of Native American towns located on what is now the Chattahoochee River. The Spanish included what is now called the Chattahoochee River as part of one river, calling all of it from its origins in the southern Appalachian foothills down to the Gulf of Mexico the Apalachicola.
Backbone Mountain is a ridge of the Allegheny Mountains of the central Appalachian Mountain Range. It is situated in the U.S. states of West Virginia and Maryland and forms a portion of the Eastern Continental Divide. In the state of Maryland, Backbone Mountain reaches an elevation of 3,360 feet or 1,024 metres, making it Maryland's highest point.
The Allegheny Front is the major southeast- or east-facing escarpment in the Allegheny Mountains in southern Pennsylvania, western Maryland, eastern West Virginia, and western Virginia, USA. The Allegheny Front forms the boundary between the Ridge-and-Valley Appalachians to its east and the Appalachian Plateau to its west. The Front is closely associated with the Appalachian Mountains' Eastern Continental Divide, which in this area divides the waters of the Ohio/Mississippi river system, flowing to the Gulf of Mexico, from rivers flowing into Chesapeake Bay and from there into the Atlantic Ocean.
The Kissimmee River is a river in south-central Florida, United States that forms the north part of the Everglades wetlands area. The river begins at East Lake Tohopekaliga south of Orlando, flowing south through Lake Kissimmee into the large, shallow Lake Okeechobee. Hurricane-related floods in 1947 prompted channelization of the meandering lower stretch, completed by 1970. The straightened course reduced wetland habitat and worsened pollution. In response, efforts since the 1990s have partially restored the river's original state and revitalized the ecosystem, as part of the broader restoration of the Everglades.
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.
A drainage divide, water divide, ridgeline, watershed, water parting or height of land is elevated terrain that separates neighboring drainage basins. On rugged land, the divide lies along topographical ridges, and may be in the form of a single range of hills or mountains, known as a dividing range. On flat terrain, especially where the ground is marshy, the divide may be difficult to discern.
The main European watershed is the drainage divide ("watershed") which separates the basins of the rivers that empty into the Atlantic Ocean, the North Sea and the Baltic Sea from those that feed the Mediterranean Sea, the Adriatic Sea and the Black Sea. It stretches from the tip of the Iberian Peninsula at Gibraltar in the southwest to the endorheic basin of the Caspian Sea in Russia in the northeast.
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.
Young Lick is a mountain that lies in three Georgia counties, Habersham, Rabun and Towns. Its summit - Young Lick Knob, elevation 3,809 feet (1,161 m), is one of Habersham County's highest points. Young Lick Knob is crossed by the Appalachian Trail.
The St. Lucie River is a 35-mile-long (56 km) estuary linked to a coastal river system in St. Lucie and Martin counties in the U.S. state of Florida. The St. Lucie River and St. Lucie Estuary are an "ecological jewel" of the Treasure Coast, central to the health and well-being of the surrounding communities. The river is part of the larger Indian River Lagoon system, the most diverse estuarine environment in North America with more than 4,000 plant and animal species, including manatees, oysters, dolphins, sea turtles and seahorses.
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 endoreic 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 bifurcation lake is a lake that has outflows into two different drainage basins and thus the drainage divide cannot be defined exactly because it is situated in the middle of the lake.
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 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.
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.
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.