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Class 15a: Water resourcesAvailability of waterDemand for waterDemand for waterDemand for waterPolitics of waterAral SeaAral SeaOgallala AquiferSolutions?Solutions?Modification of streamsWhat is water “quality”?Water quality and pollutionAgricultural runoffIndustrial/mining runoffClean Water Act (1972)Class 15a: Water resources• Water supply and demand• Modification of waterways• Water quality and pollutionAvailability of water• Only 3% of Earth’s water is fresh• Only 0.003% is available• Surface water: streams, lakes, etc.• Groundwater: found in aquifersDemand for water• Since 1950, per capita water use has tripled: why?• 1 billion people lack safe water• Depends on climate, population, level of developmentDemand for water• U.S. individual use: 180 gallons/day• Lettuce: 6 gallons• Glass of milk: 48 gallons• Eggs: 63 gallons each• Loaf of bread: 145 gallons• Pound of beef: 8,500 gallonsDemand for waterAgriculture Industry/energyHouseholdWorld 70% 25% 8%U.S. 41% 49% 10%SW U.S. 85%Politics of water• Military tool since 2500 B.C.• Jordan R., Tigris and Euphrates, Nile, etc. • “Environmental security”• Cooperation among riparian nations needed• Water wars?Aral Sea• Was the world’s fourth largest lake; now 80% gone• Central Asian desert climate• Irrigation on Amu Darya, Syr Darya– Cotton, rice– Commercial, not subsistence, farmingAral Sea• Increased salinization• Fishing industry gone• Salts and dust from dry lakebed• Rivers slow, contaminated• Climate even more continental• “Ten times worse than Chernobyl”Ogallala Aquifer• Equivalent to a Great Lake; 25-100 years left• Cattle, wheat, corn, cotton (1/5 of U.S. cropland)• Drinking water for 2 million• “Groundwater mining”– Potentially renewable resource– Used up to 22 times faster than replacedSolutions?• More groundwater (not long-term)• Diverting rivers (Columbia? Ob?)• Towing icebergs (expensive)• Desalination (expensive, energy-intensive)Solutions?• Conservation!• Est. 65-70% of water is lost (50% in U.S.)• True pricing– Less federally subsidized water in West– More metering (Sacramento)• More efficient irrigation• Reclaiming and recyclingModification of streams• Your responsibility!• Channelization– What and where– Downstream, upstream consequences• Effects of cities, deforestationWhat is water “quality”?• Depends on the use• Drinking, swimming, fishing, aquatic life, industry, etc.• 2000 EPA assessment: 40% of streams, 45% of lakes, 14% of coasts did not meet quality standardsWater quality and pollution• Biological or chemical pollutants– Pathogens, silt, metals, chemicals• Point sources: specific location• Non-point sources: dispersed location– Agriculture, industry, mining, residencesAgricultural runoff• 1/2 to 2/3 of stream pollution in U.S.• Excess fertilizer– Eutrophication– Algae blooms, “dead zone”• Herbicides, pesticides• Animal wastes (factory farms)Industrial/mining runoff• Metals, arsenic from gold mining• PCBs from industry• Mercury from industry, mining– Concentration in Arctic– Cultural, health implicationsClean Water Act (1972)• Set U.S. water quality standards• Goal of no discharge by 1985• Focus on “end of pipe”– Cheaper to violate?• Eastern rivers, Great Lakes greatly improved• Considered a legislative success


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Sac State GEOG 100 - Water resources

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