Re-entrant (landform)
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A re-entrant (international) or draw or is a
terrain Terrain or relief (also topographical relief) involves the vertical and horizontal dimensions of land surface. The term bathymetry is used to describe underwater relief, while hypsometry studies terrain relative to sea level. The Latin word ...
feature formed by two parallel
ridge A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The line ...
s or
spur A spur is a metal tool designed to be worn in pairs on the heels of riding boots for the purpose of directing a horse or other animal to move forward or laterally while riding. It is usually used to refine the riding aids (commands) and to ba ...
s with low ground in between them. The area of low ground itself is the draw, and it is defined by the spurs surrounding it. Re-entrants are similar to valleys on a smaller scale; however, while valleys are by nature parallel to a ridgeline, a re-entrant is perpendicular to the ridge, and rises with the surrounding ground, disappearing up-slope. It is usually etched in a hillside by water flow, is usually dry, but many contain an ephemeral stream or loose rocks from eroded rockfall. In a re-entrant or draw the ground always slopes downward in only one direction, and upward in the other three. The slope on a draw is generally quite sharp, with a clearly established
fall line A fall line (or fall zone) is the area where an upland region and a coastal plain meet and is typically prominent where rivers cross it, with resulting rapids or waterfalls. The uplands are relatively hard crystalline basement rock, and the coa ...
and characterized by a generally steep vertical drop over a short horizontal distance.


See also

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References

{{reflist Canyons and gorges Slope landforms