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13-4 Is Transferring Water from One Place to Another the Answer?
• Concept 13-4 Transferring water from one place to another has greatly increased water supplies in some areas, but it has also disrupted ecosystems.
Water Transfers Can Be Wasteful and Environmentally Harmful
• Using a lot of water to produce a water thirsty plant, like ________________, is not necessarily a bad thing…if the crop is grown in areas with ___________ of water
• However, U.S. lettuce primarily comes from California’s _____________ Central Valley area, and requires the use of heavy _________________
lettuce
a lot
aridirrigation
Southern California Lettuce Grown with ________________ California Water
Fig. 13-15, p. 331
Northern
California Transfers Water from Water-Rich Areas to Water-Poor Areas• Water ________________ from north to south by• Tunnels• Aqueducts• Underground pipes
• This water transfer project is called the ___________________ ___________ ___________• ___________________ water use in arid regions• Environmental damage to _______________ River
and San Francisco ___________
transferred
California Water ProjectInefficient
SacramentoBay
Fig. 13-16, p. 331
Shasta Lake Oroville Dam and
NEVADA
Sacramento RiverUTAH
CALIFORNIA
North Bay Aqueduct
Feather RiverLake Tahoe
San FranciscoSacramento SIERRA MOUNTAIN RANGE
South Bay Aqueduct
San Joaquin Valley Los Angeles Aqueduct
California AqueductColorado River
Aqueduct
ARIZONA
Colorado River
Fresno
Hoover Dam and Reservoir (Lake Mead)
Santa Barbara
Los Angeles
Central Arizona Project
San Diego Salton Sea Phoenix
Tucson
MEXICO
Reservoir
San Luis Dam and Reservoir
California Transfers Water from Water-Rich Areas to Water-Poor Areas• Projected climate change may make situation
worse…• snow packs in the _________ ______________
mountains may…• melt _________________• Receive ___________ precipitation during drought
years
• Some analysts project that during this century, many people living in arid, Southern California cities, will have to _______________ elsewhere
High Sierra
fasterless
move
Case Study: The Aral Sea Disaster (1)
• The ___________ Sea was once the world’s _______ largest lake
• 1960: has been used for a
large scale water transfer to irrigate one of the driest areas in central _____________• Cotton and rice
Aral
4th
Asia
Case Study: The Aral Sea Disaster (2)
• The large scale water transfer was also coupled with…• _____________________• High ________________ rates
• Since 1961…• Water levels have dropped by an amount equivalent
to a _____________ building• the sea’s salinity (___________ content) has risen
_________________________
drought
evaporation
6-story
saltseven-fold
Case Study: The Aral Sea Disaster (2)
• 85% of the area’s ________________ have been eliminated
• ___________ of local bird and mammal species have disappeared
• Devastated the area’s ______________ industry
• The southern portion of the Aral Sea is now a desert covered with glistening white _______________
wetlands
Half
fishing
salt
Case Study: The Aral Sea Disaster (2)
• Wind-blown salt and dust ________________ other fields and wildlife areas• Settling on the __________________ in the Himalayas
causing them to melt at a ____________ rate
• To increase yields, farmers are using _________ herbicides, insecticides, and fertilizers, which have percolated into the ___________________
pollutes
glaciersfaster
more
groundwater
Case Study: The Aral Sea Disaster (2)
• People living in the Aral Sea watershed have experienced increasing ___________ problems due to all of the pollution• Anemia• Respiratory illnesses• Liver and kidney disease• Eye problems• Various cancers
health
Case Study: The Aral Sea Disaster (2)
• Since 1999, the United Nations and World Bank have spent about $600 million to…• _________________ drinking water• _______________ irrigation and drainage systems
• Neighboring countries have been replacing water-thirsty crops with others that require ________ irrigation
• ___________ was built to raise lake levels in the Northern Aral Sea
purifyimprove
less
Dike
13-5 Is Converting Salty Seawater to Freshwater the Answer?
• Concept 13-5 We can convert salty ocean water to freshwater, but the cost is high, and the resulting salty brine must be disposed of without harming aquatic or terrestrial ecosystems.
Removing Salt from Seawater Is Costly, Kills Organisms, Creates Briny Wastewater (1)
• Desalination - removing dissolved salts from ocean water or from _____________ (slightly salty) water in aquifers or lakes• Two most widely used methods are
________________ and _______________ osmosis
• Distillation uses… • heat to evaporate water, leaving salts ______________• Cool or ___________________ steam back into liquid
water
brackish
distillation reverse
behindcondense
Removing Salt from Seawater Is Costly, Kills Organisms, Creates Briny Wastewater (1)
• Reverse osmosis…also called _________________• Uses high ______________ to force salt water
through a membrane _____________ with pores that are small enough to remove the salt
• Currently there are about ________________ desalination plants mostly in arid areas of…• Middle east• North Africa• Caribbean• Mediterranean
microfiltration
pressurefilter
14,450
Removing Salt from Seawater Is Costly, Kills Organisms, Creates Briny Wastewater (2)
• Three major problems with the widespread use of desalination1. High __________ and energy footprint2. Chemicals are required to keep down ___________
growth…____________ many marine organisms3. Produces huge quantities of ____________ salts
that must go somewhere
Bottom Line: Currently, desalination is practical only for water _____________, _______________ countries
cost
algalkill
waste
short wealthy
Science Focus: The Search for Improved Desalination Technology
Improved desalination?• Using other forms of energy to power plants…• _____________________• _____________________• _____________________
• Using ___________ to carry desalination equipment instead of land-based desalination plants• Use water from depths ______________ where most
marine organisms live• The remaining salt or _____________ could be carried
away from the coast and ___________________
solarwindocean waves
ships
below
brinediluted