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Water. The Hydrologic Cycle. “Whiskey’s for drinking, water’s for fighting over.” Western saying. The Critical Need: Water. Global Water. Ocean (Salty) 97.2 % Fresh Water 2.8 % Ice 2.15% Liquid 0.65% Groundwater 0.62% Lakes 0.009% Soil Moisture 0.005% Streams and Rivers 0.001%
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“Whiskey’s for drinking, water’s for fighting over.”Western saying
Global Water • Ocean (Salty) 97.2 % • Fresh Water 2.8 % • Ice 2.15% • Liquid 0.65% • Groundwater 0.62% • Lakes 0.009% • Soil Moisture 0.005% • Streams and Rivers 0.001% • Atmosphere 0.0001%
Why Not Use Sea Water? • Desalination now provides 1% of world drinking water • Distillation (Energy intensive) • Passive distillation (Slow, inefficient) • Reverse Osmosis (Filters delicate, prone to clogging and contamination) • Towing Antarctic Icebergs (Not done yet, but the numbers are promising)
Dams • Irrigation • Urban water supply • Hydroelectric power • Flood control • Recreation
Impacts of Dams • Human dislocation • Habitat Destruction • Terrestrial • Aquatic • Disruption of natural cycles • Sediment Starvation • Increased Evaporation • Conflict • Division of Water • Denial as weapon
The Aral Sea • Once world’s 4th largest lake • Roughly area of Lake Michigan, but only 20% of its volume • Complex history of natural diversion and dessication • Pleistocene filling from north? • Fed only by Syr Darya until Holocene • Amu Darya captured ca. 10,000 years ago.
The Aral Sea Disaster • Effects • < ¼ of original area • Destruction of fisheries • Respiratory illness from wind-blown salts • Solutions? • Ideally, stop irrigating • Dam off northern lakes and restore • Canal from Siberia?
Impacts of Groundwater Use • Aquifer depletion • Lowering of water table • Drying of wells • Danger to springs and wetlands • Invasion of contaminants • Ground subsidence