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Used to provide energy and water to southern California and Las Vegas and what is its nickname?
Colorado River Dams aka Hoover Dam
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-largest dam in the world
-1 mile long on the Yangtze River
-helps switch from coal to hydroelectricity
-dislocation of 1 million people, burial of artifacts, loss of fertile soil on floodplains
3 Gorges Dam
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creates lake Nasser
Aswan Dam, Nile River
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How does dam work?
- 1. water released from behind reservoir
- 2. enters dam
- 3. water spins a turbine machine in dam
- 4. turbine generate hydroelectricity
- 5. electricity delivered 2 cities via power lines
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dams advantages?
- -supply water year round
- -electrical power
- -recreation benefits =boating and fishing
- -no air pollution
- -water used for agriculture
- -inexpensive electricity
- -long economic life
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dams cons?
- -expensive to build, loss of human lives
- -sediments don't flow downstream-->loss of nutrients
- -evaporation of fresh water behind dam-->increase salinity which affects salinity in fish's habitat (decrease in fish population)
- -fish cant travel upstream (salmon)
- -increased risk of disease-->stagnant water (mosquitoes and malaria)
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what happens when dam failure occur?
FLOOD!
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steelhead and rainbow trout differences? similarities
- -born in freshwater rivers (rainbow)
- -swim out to the ocean (steelhead)
- -same fish but their name depends on their location
- -return to same river (travel upstream) to have their babies
- -if dam is in place, cannot return to have babies -->die
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how to solve the dam problem for steelhead/rainbow trout?
- fishladder!
- series of steps the fish hop over to travel upstream (get over dam)
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diverts or directs water to places in need
(irrigation, drinking water)
water diversion
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examples of wter diversion
LA and Colorado aqueducts
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in the nation of kazakhstan
-rivers to inland sea have been diverted for irrigation
Aral Sea
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-evaporation has increased salinity, no fish species exist
-salt is blown to surrounding area which causes health problems and decreasing crop population
Case Study: Aral Sea
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What was Aral sea known for?
the 4th largest freshwater lake
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irrigation
farmers must heavily irrigate-water crops so plants can grow and remove salt
water conservation
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lessen water: use of lasers, central pivot watering systeams, timers
efficient irrigation system
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-untreated material from water pipes from homes/industry
raw sewage
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releases pathogens (disease causing agents) into ground or surface water
crack/sewer lines break
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-creates 25,000,000 deaths yearly
-comes from untreated human wastes and animal wastes
-2.5 billion lack sanitation
-most serious water pollutants in terms of health
-causes diarrhea, cholera, dysentery
disease causing agents
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excess nitrates, phosphates cause eutrophication
inorganic plant nutrients
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excessive algal growth
eutrophication
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example of eutrophication
red tide = bloom of dinoflagellates
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Organic Compounds Oil
Exon Valdez-->Prince William Sound
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what does organic compounds make?
plastics! and they are found in Africa
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In-organic chemicals
- -heavy metals: Hg, Cadmium, Ni, Pb
- -comes from: lead pips, coal burning (Hg), mining wastes, tin, Cu on boat hulls
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what does inorganic chemical metals cause?
causes mental retordation
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1932: Chisso Corporation made acetaldehyde
Hg: industrial byproduct discharged into bay
Case Study: Minamata Japan
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results of Minamata, Japan case study
- -1st symptom: fish/cats began showing weird signs
- -1956: humands had lost of motor control -->partly paralized and contored body
- 1963: "Minamata Disease" traced to Hg from Chisso where people ate fish with Hg
- -forced to dredge bay and pay victims
- -1,784 died, 86 million in compensation
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-factories/industries locate near land water to cool down
-raising or lowering temp. from normal levels
-from industrial coolant outflors (to cool electrical power plants
thermal pollution
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what are the results of thermal pollution
- lowers dissolved oxygen levels (O2 in water)
- thermal shock!
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organisms killed by abrupt change in temp. of water
thermal shock
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