EESA01H3 Lecture : lec 5
19 Dec 2011
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Document Summary
Freshwater systems y roughly 97. 5% of earth s water resides on the oceans and is too salty to drink or to use to water crops: 2. 5% is considered freshwater , water that is relatively pure, with few dissolved salts. some of which is tied up in glaciers, icecaps and underground aquifers, just over y water is moving among reservoirs via the hydrological cycle. 1 part in 10000 of earth s water is easily accessible for human use: as it moves it redistributes heat, erodes mountain ranges, builds river deltas, maintains organisms and ecosystems, shapes civilizations, and gives rise to political conflict. Rivers and streams wind through landscapes y water from rain, snowmelt, or springs runs downhill and converges where the land dips lowest, forming streams, creeks or brooks: these watercourses merge into rivers, which eventually lead to ocean. a small river flowing into a larger one is a tributary.
