A water divide (also known in Commonwealth usage as a watershed) is the separation between neighbouring drainage basins, and lies along topographicalpeaks and ridges. Water divides are important geographical, and often also political, boundaries. A water divide is also sometimes called a water parting or a height of land (in North America, especially Canada).
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.