geo 139 - Geography 139 April 7th Reading Ch 5 something...

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Geography 139 April 7th Reading Ch. 5 something new under the sun Water Use and Pollution Chapter 5 The Hydrosphere: The History of Water Use and Water Pollution Water Basics With modern currents of industrialization, high energy use, and urbanization, societies acquired greater power with which to move and control water. This caused more usage, waste, and pollution. The health, wealth, and security of societies depended on supplies of clean water to the right places at right times without doing too much damage. Water management is a crucial technical and political challenge. The Earth’s hydrosphere = 1.4 billion cubic kilometers 97% is salt water in oceans Solar desalination and purification machine pumps up about half a million cubic km every year, which falls back to earth as rain and snow. This is the source of all the world’s stock of fresh water. Most of that (69%) is locked up in ice caps and glaciers mostly in Antarctica Almost all the remainder (98%) lies underground in aquifers most as inaccessible depths. About 1/4 of that 1% of the world’s fresh water is in lakes and rivers. Of this about 1/4 is in Lake Baikal in Siberia. Small amounts of freshwater are in permafrost, atmosphere, and living things. The world’s renewable flow of fresh water is somewhat less than its total freshwater stock. Continents get more rain than they surrender in evaporation and the difference is the world’s streamflow (about 40,000 km^3 every year). 2/3 of this runs off in floods, so about 14,000 cubic km per year is available for use. This comes to more than 2,00 cubic meters per person annually, which is plenty. 20 or 30 countries mostly in Africa and Southwestern Asia have less than half this figure South America has ten times as much per person as Asia and five times as much as Africa. The inconvenient distribution of fresh water, coupled with the expense of transporting it over long distances, has made water supply a major constraint on human affairs. Many societies have invested heavily in efforts to ease constraint. World Water Use And Supply In history of water use some things have changed but one thing has stayed the same. ..IRRIGATION.
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This note was uploaded on 12/11/2011 for the course GEOGRAPHY 139 taught by Professor N/a during the Spring '11 term at University of Wisconsin.

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geo 139 - Geography 139 April 7th Reading Ch 5 something...

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