Water Resources

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Water Resources
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Key Concepts

• The physical properties of water

• Availability of fresh water

• Methods of increasing freshwater supplies

• Using water more efficiently

• Problems associated with flooding

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Waters Unique Properties

• Hydrogen bonding

• Liquid over wide temperature range

• Changes temperature slowly

• High heat of evaporation

• Great dissolving power

• Filters out ultraviolet radiation

• Adhesion and cohesion

• Expands when it freezes

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Hydrogen Bonding in Ice
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Hydrogen Bonding in Water
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Supply of Water Resources
All water
Fresh water
Readily accessible fresh water
Groundwater 0.592
Biota 0.0001
Rivers 0.0001
Lakes 0.007
Lakes 0.007
0.014
Fresh water 2.6
Ice caps and glaciers 1.984
Oceans and saline lakes 97.4
Soil moisture 0.005
Oceans and saline lakes 97.4
Ice caps and glaciers 1.984
Atmospheric water vapor 0.001
Soil moisture 0.005
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Supply of Freshwater Resources
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Surface Water

• Surface runoff

• Watersheds

• Reliable runoff

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Ground Water
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Water Budget
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Use of Water Resources

• Humans use about 54 of reliable runoff

• Agriculture

• Industry

• Domestic

• Power plants

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400,000 liters (106,000 gallons)
1 automobile
1 kilogram cotton
10,500 liters (2,400 gallons)
1 kilogram aluminum
9,000 liters (2,800 gallons)
1 kilogram grain-fed beef
7,000 liters (1,900 gallons)
1 kilogram rice
5,000 liters (1,300 gallons)
1 kilogram corn
1,500 liters (400 gallons)
1 kilogram paper
880 liters (230 gallons)
220 liters (60 gallons)
1 kilogram steel
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Too Little Water

• Dry climate

• Drought

• Desiccation

• Water stress

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Average annual precipitation (centimeters)
Less than 41
81-22
More than 122
41-81
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Acute shortage
Shortage
Adequate supply
Metropolitan regions with population greater than
1 million
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Freshwater Stress
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Using Dams and Reservoirs to Supply More Water
The Trade-offs
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Pueblo Dam, Colorado
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Silt filled Reservoir behind a Dam
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Wash.
N.D.
Montana
Oregon
S.D.
Idaho
Wyoming
Neb.
Nevada
Colo.
Utah
Kansas
California
Oak.
N.M.
Texas
Highly likely conflict potential
Substantial conflict potential
Moderate conflict potential
Unmet rural water needs
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Europe
North America
Asia
Africa
South America
Australia
Stress
High
None
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Transferring Water from One Place to Another

• Watershed transfer

• California Water Project

• Central Arizona Project

• James Bay

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CALIFORNIA
NEVADA
Shasta Lake
UTAH
Oroville Dam and Reservoir
Sacramento River
Feather River
Lake Tahoe
North Bay Aqueduct
Sacramento
San Francisco
Hoover Dam and Reservoir (Lake Mead)
Fresno
South Bay Aqueduct
Colorado River
Los Angeles Aqueduct
San Luis Dam and Reservoir
ARIZONA
California Aqueduct
Central Arizona Project
Colorado River Aqueduct
Santa Barbara
Los Angeles
Phoenix
Salton Sea
San Diego
Tucson
MEXICO
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CANADA
Hudson Bay
Chisasibi
NEWFOUNDLAND
II
James Bay
I
ONTARIO
II
QUEBEC
New York City
ATLANTIC OCEAN
Chicago
UNITED STATES
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IDAHO
WYOMING
Dam
Aqueduct or canal
Salt Lake City
Grand Junction
Upper Basin
Denver
Lower Basin
UPPER BASIN
UTAH
COLORADO
Lake Powell
Grand Canyon
Glen Canyon Dam
Las Vegas
NEW MEXICO
Boulder City
ARIZONA
CALIFORNIA
Albuquerque
LOWER BASIN
Los Angeles
Palm Springs
Phoenix
0
100 mi.
San Diego
Yuma
0
150 km
Mexicali
Tucson
All-American Canal
MEXICO
Gulf of California
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Trade-Offs
Chinas Three Gorges Dam
Advantages
Disadvantages
Will generate about 10 of Chinas
electricity Reduces dependence on
coal Reduces air pollution Reduces CO2
emissions Reduces chances of downstream
flooding for 15 million people Reduces river
sitting below dam by eroded soil Increases
irrigation water for cropland below dam
Floods large areas of cropland and
forests Displaces 1.9 million
people Increases water pollution because of
reduced water flow Reduces deposits of
nutrient- rich sediments below dam Increases
saltwater Introduced into drinking water near
mouth of river because of decreased water
flow Disrupts spawning and migration of some
fish below dam High cost
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Tapping Groundwater

• Year-round use

• No evaporation losses

• Often less expensive

• Potential Problems!

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Problems with Using Groundwater

• Water table lowering

• Depletion

• Subsidence

• Saltwater intrusion

• Chemical contamination

• Reduced stream flows

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Water in the Ground (USGS)
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Trade-Offs
Withdrawing Groundwater
Advantages
Disadvantages
Good source of water for drinking and
irrigation Available year-round Exists almost
everywhere Renewable if not over- pumped or
contaminated No evaporation losses Cheaper to
extract than most surface waters
Aquifer depletion from over- pumping Sinking of
land (subsidence) when water removed Polluted
aquifers unusable for decades or
centuries Saltwater intrusion into drinking
water supplies near coastal areas Reduced water
flows into streams, lakes, estuaries, and
wetlands Increased cost, energy use, and
contamination from deeper wells
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Groundwater Overdrafts
High
Moderate
Minor or none
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Wells
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Major irrigation well
Well contaminated with saltwater
Water table
Sea Level
Salt water
Fresh groundwater aquifer
Interface
Interface
Saltwater Intrusion
Normal Interface
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Eastern US Aquifers Contaminated with Saltwater
(USGS)
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Converting Salt Water to Fresh Water and Making
it Rain

• Distillation desalination

• Reverse osmosis desalination

• Desalination is very expensive

• Cloud seeding

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Distillation desalination
Reverse osmosis desalination
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Using Water More Efficiently

• Reduce losses due to leakage

• Reform water laws

• Improve irrigation efficiency

• Improving manufacturing processes

• Water efficient landscaping (xeriscaping)

• Water efficient appliances

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Too Much Water Floods

• Natural phenomena

• Aggravated by human activities

Reservoir
Dam
Levee
Flood wall
Floodplain
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Stages of Stream Development
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Ansel Adams Snake River
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Flood Plains
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Solutions
Groundwater Depletion
Prevention
Control
Raise price of water to discourage
waste Tax water pumped from Wells near
surface water Set and enforce minimum
stream flow levels
Waste less water Subsidize water conservation Ba
n new wells in aquifers near surface
waters Buy and retire ground- water withdrawal
rights in critical areas Do not grow
water- intensive crops in dry areas Reduce
birth rates
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WYOMING
SOUTH DAKOTA
Less than 61 meters (200 ft)
61-183 meters (200-600 ft)
More than 183 meters (600 ft) (as much as 370
meters or 1,200 ft. in places)
NEBRASKA
KANSAS
COLORADO
OKLAHOMA
NEW MEXICO
TEXAS
Miles
0
100
0
160
Kilometers
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Solutions Achieving a More Sustainable Water
Future

• Efficient irrigation

• Water-saving technologies

• Improving water management

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Center Pivot (efficiency 80 with low-pressure
sprinkler and 9095 with LEPA
sprinkler) Water usually pumped from
underground and sprayed from mobile boom with
sprinklers.
Drip Irrigation (efficiency 90-95) Above- or
below-ground pipes or tubes deliver water to
individual plant roots.
Gravity Flow (efficiency 60 and 80 with surge
valves) Water usually comes from an aqueduct
system or a nearby river.
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Colorado Center Pivot Irrigation
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Water Conserving Center Pivot Irrigation
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Flood Irrigation
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Furrow Irrigation
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Drip Irrigation
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Solutions
Reducing Irrigation Water Waste

• Lining canals bring water to irrigation ditches
• Leveling fields with lasers
• Irrigating at night to reduce evaporation
• Using soil and satellite sensors and computer
  systems to monitor soil moisture and add water
  only when necessary
• Polyculture
• Organic Farming
• Growing water-efficient crops using
  drought-resistant and salt tolerant crops
  varieties
• Irrigating with treated urban waste water
• Importing water-intensive crops and meat

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Solutions
Reducing Water Waste

• Redesign manufacturing processes
• Landscape yards with plants that require little
  water
• Use drip irrigation
• Fix water leaks
• Use water meters and charge for all municipal
  water use
• Use waterless composting toilets
• Require water conservation in water-short cities
• Use water-saving toilets, showerheads, and
  front-loading clothes washers
• Collect and reuse household water to irrigate
  lawns and non-edible plants
• Purify and reuse water for houses, apartments,
  and office buildings

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Xeriscaping in Arizona
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Oxygen released by vegetation
Diverse ecological habitat
Evapotranspiration
Trees reduce soil erosion from heavy rain and wind
Agricultural land
Steady river flow
Leaf litter improves soil fertility
Tree roots stabilize soil and aid water flow
Vegetation releases water slowly and reduces
flooding
Forested Hillside
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Tree plantation
Evapotranspiration decreases
Roads destabilize hillsides
Ranching accelerates soil erosion by water and
wind
Winds remove fragile topsoil
Agriculture land is flooded and silted up
Gullies and landslides
Heavy rain leaches nutrients from soil and erodes
topsoil
Rapid runoff causes flooding
Silt from erosion blocks rivers and reservoirs
and causes flooding downstream
After Deforestation
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Solutions
Sustainable Water Use

• Not depleting aquifers
• Preserving ecological health of aquatic systems
• Preserving water quality
• Integrated watershed management
• Agreements among regions and countries sharing
  surface water resources
• Outside party mediation of water disputes between
  nations
• Marketing of water rights
• Raising water prices
• Wasting less water
• Decreasing government subsides for supplying
  water
• Increasing government subsides for reducing water
  waste
• Slowing population growth

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What Can You Do?
Water Use and Waste

• Use water-saving toilets, showerheads, and faucet
  aerators
• Shower instead of taking baths, and take short
  showers.
• Repair water leaks.
• Turn off sink faucets while brushing teeth,
  shaving, or washing.
• Wash only full loads of clothes or use the lowest
  possible water-level setting for smaller loads.
• Wash a car from a bucket of soapy water, and use
  the hose for rinsing only.
• If you use a commercial car wash, try to find one
  that recycles its water.
• Replace your lawn with native plants that need
  little if any watering.
• Water lawns and garden in the early morning or
  evening.
• Use drip irrigation and mulch for gardens and
  flowerbeds.
• Use recycled (gray) water for watering lawns and
  houseplants and for washing cars.