Water divide
From Wikipedia, the free encyclopedia
A water divide, drainage divide, or simply divide is the separation between neighbouring drainage basins (catchments). In hilly country, the divide lies along topographical peaks and ridges, but in flat country or on a high plateau (especially where the ground is marshy) the divide may be invisible - just a more or less notional line on the ground on either side of which falling raindrops will start a journey to different rivers, and even to different sides of a country or continent. Water divides are important geographical, and often also political, boundaries.
A divide is also known as:
- a watershed (although in North America this term is old-fashioned or nontechnical, since it usually refers to the drainage basin);
- a water parting;
- a height of land (in Canada).
[edit] Types of water divide
Water divides can be grouped in three types:
- Continental divide — A divide in which the waters on each side flow to different oceans (example: the Nile and Congo divide)
- Major water divide — The waters on each side of the divide never meet again, but do flow into the same ocean (example: the divide between the Yellow River basin and the Yangtze)
- Minor water divide — The waters part but eventually meet again at a river confluence (example: the Mississippi and Missouri divide)
Water divides are a hindrance to river navigation. In pre-industrial times water divides were crossed at portages. Later canals were built to connect the adjoining drainage basins.
[edit] External links
- Water divide and "Canal du Midi" (in French)