1. C H A P T E R 1 1 , S E C T I O N 2 : WA T E R U S E &
M A N A G E M E N T
S T A N D A R D S : S C S H 2 A - B , 3 C , 4 A , 5 A , 6 A , D , 9 D
WATER

2. HOW DO PEOPLE USE WATER?
• Agricultural Use
• Industrial Use
• Residential/
Domestic Use
0
10
20
30
40
50
60
70
Irrigation
Industry
Domestic

3. HOW IS WATER USED IN RESIDENTIAL
AREAS?
• 14% of world water use
• Varies by country
• Average person needs
1.3 gallons to survive
• U.S. resident uses 80
gallons per day
• India resident uses 10
gallons per day
• In U.S. we use it for
• Inside sources: drinking,
cooking, washing, toilet
flushing, etc.
• Outside sources:
watering lawns, washing
cars, etc.
0
5 0
10 0
15 0
2 0 0
2 5 0
Unit e d
S t a t e s
Ne t he r la nd
s
Ga mbia

5. HOW IS WATER TREATED TO MAKE IT
POTABLE (DRINKABLE) IN RESIDENTIAL
AREAS?
• Need to remove mercury, lead, arsenic, pathogens (disease
causing organisms), etc.
• Steps to treat water…
• First Filtration
• Large materials/trash removed
• Coagulation/Sedimentation
• Alum is added to clump up large dirt particles into globs called floc. This settles
to the bottom of the tank and creates sludge. Sludge can be removed,
disinfected & used as fertilizer.
• Second Filtration
• Water passed through filter of sand, gravel, charcoal to remove impurities
• Chlorination
• Chlorine is added to prevent bacteria from growing in water.
• Aeration
• Air is forced thru water to release unwanted gases which reduces odor &
improves taste.
• Additional Treatment
• Fluoride is added to prevent tooth decay
• Sodium compounds or lime may be added to soften hard water (hard water will
not lather when soap is added)
• Storage
• Sent to water tower before pumped to homes/businesses

7. HOW IS WATER USED IN INDUSTRY?
• 19% of world water use.
• Mostly used to cool
power plants
• Pump out river water, water
boiled, produces steam,
turns turbines, water re-
condensed and cooled in
cooling towers, either
reused or returned to river.
• Manufacture goods
• 1,000L used to produce 1kg
of aluminum for cans
• 500,000L used to produce a
car
• Dispose of waste

8. HOW IS WATER USED IN
AGRICULTURE?
• 67% of world water use
• Irrigation
• Providing plants with
water from sources other
than direct rainfall.
• Traditional
• Flood furrows
• Lose a lot to evaporation
• Modern
• Overhead sprinklers
• Some evaporates
• Drip irrigation
• Most efficient but most
expensive (replace hoses)

9. WHAT ARE WATER MANAGEMENT
PROJECTS?
• Creation of dams,
canals, aqueducts,
& reservoirs to meet
the needs of
people.
• Ex:
• Mono Lake in
California
• Three Gorges Dam in
China

10. MONO LAKE, CA
• In 1941, L.A. started
diverting Mono Basin
streams to add to L.A.
Aqueduct.
• Mono Lake’s volume
halved while salinity
doubled. The simple
ecosystem began to fail
and threatened migrating
birds and nesting gulls.
• The state and courts now
mandate raising the level
of the lake 17 feet. It will
take about 20 years.
• Should make more
habitable for birds & fish

11. PROS & CONS OF DAMS
• Pros:
• Creates reservoir- artificial
lake behind dam
• Collect and store water
from rain and snow
• Produce electricity
• Irrigate farm land
• Control flooding
• Provide drinking water to
cities, towns and rural
areas
• Provide recreational
activities such as
swimming, boating, fishing
• Cons:
• Enormous loss of water due
to evaporation
• Flooded land destroys
forests or cropland and
displaces people
• Danger of Dam collapse
• Downstream areas
deprived of nutrient-rich
soil, which will eventually
clog the reservoir
• Migration and spawning of
fish disrupted
• Causes water wars
between states & countries
• Expensive to build

12. WHAT ARE SOME WAYS TO CONSERVE
WATER?
• As water becomes
depleted, water
becomes more
expensive.
• Dig deeper wells
• Send water through
pipes a greater
distance
• Clean polluted water
• Conservation is best
method of solving
water shortage
problems.

13. WHAT ARE SOME WAYS TO CONSERVE
WATER?
• Agriculture
• Most problems with evaporation,
seepage, and runoff
• Drip irrigation systems deliver
water directly to roots via
perforated tubing- less
evaporation
• Industry
• Recycle cooling water
• Residential
• Low flow toilets/shower heads
• Turn off water while brushing
teeth.
• Xeriscaping- using drought
tolerant plants in landscaping so
you don’t have to water them
too much.
• Water lawn at night

14. WHAT ARE SOME SOLUTIONS TO THE
WATER DEPLETION PROBLEM?
• Desalination
• Removing salt from
ocean water
• Two methods:
• Distillation- heat &
evaporate fresh water,
leaving salts behind
• Reverse osmosis- pass
water through
membranes that trap
salt
• Expensive
• Ex: Middle East,
coastal communities

15. WHAT ARE SOME SOLUTIONS TO THE
WATER DEPLETION PROBLEM?
• Transporting Fresh
Water
• Melt water at source,
bag it and transport it
to areas in need.
• Towing icebergs-
efficient technology
not developed yet.

16. YOU SHOULD BE ABLE TO…
• Describe the patterns of global water use for each
continent shown in the bar graph in Figure 5.
• Describe the drinking water treatment process in
your own words.
• Describe the benefits and costs of dams and water
diversion projects.
• List at least three things you would do to help
conserve the world’s water supply.