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: http://zebu.uoregon.edu/1995/ph161/l9.html
Дата изменения: Fri Oct 17 22:24:39 1997
Дата индексирования: Tue Oct 2 00:04:35 2012
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The Hydrological Cycle
Active Pools:
- Atmosphere: 720,000
- Soil Moisture 3,700,000
- Stream Channels 69,000
- Fresh Water Lakes 6,900,000
- Saline Lakes/Inland Seas 5,800,000
- Oceans 74,000,000,000
Storage Pools:
- Ice Caps and Glaciers 1,600,000,000
- Groundwater 460,000,000
Groundwater is a major untapped source of fresh water but
everyday more toxins seep into it. Note that there is
approximately 5000 times more water stored as groundwater
than is in surface streams
Components of the Hydrological Cycle
Dam building seriously alters
the hydrological cycle.
This is especially true in the American
Southwest
What happened to the
Colorado River
- Originally it reached northern mexico and fed a thriving
agrarian economy in the early 20th century
- Source is in Rocky Mountains of Colorado
- San Juan mountains in SW colorado have a large snowpack,
which feeds the river
- In 1922 the water rights to the river were allocated
to California, Arizona, Nevada, Utah and Colorado
- Allocation was based on river flow during the period 1900-1920
which turns out to have been anamolously high --> therefore the
river was overallocated
- Depression hits so Hoover dam is built as part of the effort to
reclaim the West
(see also the excellent Cadillac Desert Series
- Water backs up into reservoir and increases surface area to
evaporation
- Reservoir lined with porous sandstone so water loss due to
seepage into sandstone occurs
- Lake Havasu
was created for London Bridge --> additional
recreational dams were built (e.g.
Parker Dam
- As more and more of the Colorado became prown to evaporation
its salinty increased
- Eventually the water that reached Mexico was too saline for
agriculture. Mexican government sued and won. US built a nuclear
powered desalination plant in Yuma Arizona
- Now no water gets there ... unless we really
pour it on
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