Transcript Water and Water Pollution Chapters 13 and 20 Living in the

Water
Key H20 Characteristics
• Water is the prime constituent
of all living organisms.
• Water moves easily-from one
physical state to another, and
from one place to another.
• Water slowly absorbs and
releases large quantities of
energy.
• Water is a superior solvent.
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Michael D. Lee Ph.D. Geography and Environmental Studies
(Source: Wright & Nebel 2002)
Importance of Water Properties
Running water can
quickly erode topsoil
rendering farmland
infertile and streams
contaminated.
Lack of access to
clean water supplies
can quickly lead to
dehydration and
death.
Chemical spills,
excess nutrients &
acids dissolved in
H20 can lead to
massive die offs.
Michael D. Lee Ph.D. Geography and Environmental Studies
• Water
–Supply, Renewal and Use
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Too little Water
Dams and Reservoirs
Transferring water
Groundwater and Saltwater
Efficiency
Too Much Water
• Water Pollution
Available Water
• Total = 326 million cubic miles
• 97% of Earth’s water is in
oceans
• 2.997% is locked up in ice caps
and glaciers
• 0.003% is easily accessible
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Soil moisture
Groundwater
Water vapor
Lakes
Streams
Water Supply & Use
http://ga.water.usgs.gov/edu/waterdistribution.html
Water Cycle
Hydrologic Cycle
• Powered by solar energy and gravity
• Evaporation and precipitation
• Continuous recycling of water
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Runoff
Infiltration
Evaporation
Temporary storage as snow and ice
Temporary storage in lakes
Temporary storage in plants (transpiration) and animals
Chemical reactions with rocks and minerals
Volcanism also causes melting of snow caps and
mudflows as melted water mixes with ash
– Source of additional water? volcanism (steam)
Surface Water
• Surface runoff flows into streams, lakes,
wetlands and reservoirs
• A watershed or drainage basin
– Region that drains into a streams, lakes,
wetlands or reservoirs
www.canaanvi.org/assistance/ watershed.asp
Groundwater
• As precipitation infiltrates and percolates
through voids in soil and rock
– Pores, fractures, crevices, etc.
• Shallow rock has little moisture
• Zone of saturation is at a depth were ground
is filled with water
• Top of this zone is water table
– Falls in dry weather
– Rises in wet weather
HOW RIVERS
WORK: the role of
groundwater
www.elmhurst.edu/.../chm110/ outlines/groundwater.html
Aquifers
• Porous, water-saturated layers of sand,
gravel or bedrock through which
groundwater flows
• Area of land that supplies water to aquifer is
called the recharge area
• Natural recharge is when water percolates
downward, but sometimes lateral recharge
occurs
Groundwater Movement
• Groundwater moves from recharge area
through an aquifer and out a discharge area
– well, spring, lake, geyser, artesian well, steam,
ocean
• Normally moves downhill at only a meter
per year
• Some aquifers get little recharge and were
formed thousands of years ago
• Removal from these nonrenewable
resources is called water mining
Use of Fresh Water
United States
China
• 41% agriculture
• 38% power plant cooling
• 11% industry
• 10% public
• 87% agriculture
• 7% industry
• 6% public
Water Use Globally
People and Planet
• 70% of all water withdrawn
for human use on an annual
basis is soaked up by
agriculture (mostly in the
form of irrigation)
• Industry accounts for 23%
• Domestic use (household,
drinking water, sanitation)
accounts for about 7%
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Irrigation
Industry
Dome stic
Water Use
People and Planet
• The average person needs a minimum of
five litres (1.3 gallons) of water per day to
survive in a moderate climate at an average
activity level, according to UN figures.
• The minimum amount of water needed for
drinking and cooking, bathing and
sanitation is 50 litres (13 gallons) per day.
Water Use - (minimum 13 gallons) People and Planet
250
• The average person in the
United States uses between 250
to 300 litres of water (65-78
gallons) per day for drinking,
cooking bathing, and watering
their yard.
• The average person in the
Netherlands uses 104 litres per
day (27 gallons).
• The average person in the
African nation of Gambia uses
4.5 litres per day (1.2 gallons of
water).
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United States
Netherlands
Gambia
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Water Use - United States
• In 1990, about 408,000 million gallons (Mgal/d)
of water were used each day
• Of that, about 339,000 Mgal/d was fresh water
and about 69,400 Mgal/d was saline water
• California used the most water, about 46,800
Mgal/d, with most of that going towards
irrigation
• The state with the second-highest water use was
Texas, with about 25,200 Mgal/d, mostly for use
in the power-production industries and for
irrigation
• Some conversions:
• 1 Mgal/d = 1.547 cubic feet per second
• 1 Mgal/d = 0.6944 thousand gallons per minute
• 1 Mgal/d = 1,121 thousand acre-feet per year
• 1 million gallons = 3.07 acre feet
http://ga.water.usgs.gov/edu/wateruse.html
• Water
– Supply, Renewal and Use
–Too little Water
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Dams and Reservoirs
Transferring water
Groundwater and Saltwater
Efficiency
Too Much Water
• Water Pollution
Too Little Water
• Causes
– Dry climate
– Drought - a period in which precipitation is
much lower and evaporation is much higher
– Desiccation - drying of soil because of such
activities as deforestation and overgrazing
– Water stress - low per capita availability of
water caused by overpopulation
Precipitation Varies Greatly
• US cities vary in their precipitation from an
average of less than 8 to 60 inches a year.
• Globally, the extreme is even greater –
averages of less than 1 inch to more than 70
inches per year.
• However, this masks variations between years.
• Some locations may get ten times more, or
less than 1/10 of their annual average from
year to year.
• Meeting demands for water when precipitation
is so highly varied creates many challenges.
www.geocities.com/seafloormapping2/ atmos.htm
whyfiles.org/131fresh_water/ 2.html
Global Precipitation Patterns
Wright and Nebel, 2002.
Michael D. Lee Ph.D. Geography and Environmental Studies
http://www.peopleandpla
net.net/graphs/Freshwate
ravailability.jpg
• In most areas of
Nevada and
California,
potential
transpiration and
evaporation is in
excess of
precipitation,
which causes a net
moisture deficit
Drought may spark food price hike
Tuesday, November 12, 2002
SYDNEY, Australia -All but one percent of
Australia's most populous
state, New South Wales,
has been bit by the
country's worst drought in
a century, with retailers
warning that if rain does
not fall soon, the country
will likely face massive
food price hikes.
• Water
– Supply, Renewal and Use
– Too little Water
– Dams and Reservoirs and
– Transferring water
– Groundwater and Saltwater
– Efficiency
– Too Much Water
• Water Pollution
Water and Civilization
• Many anthropologists and historians believe the need to
manage water played a major role in the development of
early systems of government.
• In Mesopotamia, in the Fertile Crescent where the Tigris and
Euphrates Rivers come together, water allowed the rise of
irrigation-based agriculture, but this required coordination
and rules to permit equitable access to water downstream.
• Proto-laws and governments were thus
developed some 4,400 years BP
• Ancient communities that prospered
were those that generally well managed
their water supplies.
Michael D. Lee Ph.D. Geography and Environmental Studies
Examples of Water Management
• Many civilizations built impressive water management systems
– to bring water to places where people wanted to be or where
crops could be grown, but where it was naturally insufficient.
• Egyptians built dykes, canals and water lifts to extend
agricultural limits.
• Middle East and North African nomads built qanats
(underground chain wells).
• Nabateans built runoff harvesting systems – cisterns and flood
terraces.
• Incas built canals to catch snowmelt from the Andes to the
coastal desert, and terraces to flood for farming.
• Romans built municipal aqueducts and sewers to serve
burgeoning settlements.
• For a good, fun site on water history go here.
Michael D. Lee Ph.D. Geography and Environmental Studies
Egyptians perfected the shadouf to
draw water from canals and the river to
the adjacent bank and into ditches.
Michael D. Lee Ph.D. Geography and Environmental Studies
Nomadic herders and, later, sedentary
civilizations developed chains of
wells – qanats, karez, foggaras, falaj –
to route water across miles of desert
from distant aquifers.
Water for Power
• In addition to its uses for municipal purposes (drinking,
sanitation, etc.) and for farming, moving water also has
tremendous power to do work.
• This too has been harnessed for millennia – first to lift water
out of the river itself, then to grind grain and turn gears for
machinery like looms, and then for electricity.
• Water wheels have been in use for more than 2,000 years and
were thought to have been a major factor in the advancement
of European societies in the middle ages, as labor was freed
for other purposes than farming.
• Following the discovery of electricity and the pioneering of
electric light by Edison, in the 1880s hydropower systems
were built to generate electricity to send through transmission
lines to homes and businesses.
Michael D. Lee Ph.D. Geography and Environmental Studies
Example of noria – water
driven wheels lifting water
into irrigation ditches or
elevated aqueducts (This is
in Vietnam)
Slaters Mill in Rhode
Island, one of the
earliest American
water powered
industrial systems.
Artists impression of the Three
Gorges Project, Yangtze River,
China – world’s biggest
hydropower project 19 m kW.
Michael D. Lee Ph.D. Geography and Environmental Studies
Increasing Water Supplies
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Build dams and reservoirs to store runoff
Bring in surface water from another area
Withdraw groundwater
Convert salt water to fresh water
(desalination)
• Improve the efficiency of water use
Aswan Dam, Egypt
Chinese Dam
Fish Bypass System
Earthen Dam
Hoover Dam
Large Dams - Pros
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Collect and store water from rain and snow
Produce electricity
Irrigate land below the dam
Control flooding
Provide water to cities, towns and rural areas
Provide recreational activities such as
swimming, boating, fishing
Large Dams - Cons
• Enormous loss of water due to evaporation
• Mass of water can cause earthquakes
• 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
• Expensive to build