Transcript Chapter 13

Chapter 13
Water Conflicts in the Middle East:
 Water shortages in the Middle
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East: hydrological poverty
Nile River – flows through 7
countries for irrigation and
drinking water. Ethiopia,
Sudan, Egypt.
Jordan Basin – most water
short,
Tigris and Euphrates Rivers –
Turkey
Conflicts will increase among
nations that share water
resources
Three Major River Basins in
the Middle East
Freshwater Is an Irreplaceable Resource
 Covers 71% of the earth’s surface
 Water sculpts the earth’s surface
 Moderates climate
 Removes, dilutes pollutants and wastes
 -------------------------------------------------------------- Poorly managed resource
 waste and pollute
 charge too little to make it available
Water is an irreplaceable resource
 Global health issue : lack of safe drinking water and
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sanitation is the world’s single largest cause of illness
2007 – WHO – 1.6 million – 90% of them under 5 die from
waterborne diseases – diarrhea, typhoid, hepatitis
Economic Issue : vital for reducing poverty
Developing countries – women and children’s issue
National and global security issue : increasing tensions
within and between nations over shared resources
Environmental issue : excessive withdrawal of water
from rivers and aquifers lowers water tables, lower river
flows, shrinking lakes, reduce fish populations, species
extinction, degradation of ecosystem services.
Girl Carrying Well
Water over Dried
Out Earth during a
Severe Drought
Most of the Earth’s Freshwater Is Not
Available to Us
 About 0.024% available as liquid water in
groundwater deposits, lakes, rivers, and streams
 Rest in salty oceans, frozen in polar ice caps and
glaciers, deep underground
 Hydrologic cycle
 Movement of water in the seas, land, and air
 Driven by solar energy and gravity
 People divided into
 Water haves
 Water have-nots
We Get Freshwater from Groundwater and
Surface Water
 Ground water – precipitation filters downwards through
spaces in soil, gravel and rock until a layer of rock stops it
 Zone of saturation – spaces in soil and rock close to the
earth’s surface are completely filled with water
 Water table – top of the ground water zone, falls in dry
weather or when ground water removed too fast
 Aquifers – underground caverns and porous layers of
sand, gravel or bedrock through which ground water
flows, large elongated sponges, moves 1 meter/year
 Natural recharge –downward percolation through soil and
rock
 Lateral recharge – from nearby rivers and streams
We Get Freshwater from Groundwater and
Surface Water
 Surface Water – freshwater from precipitation and snow melt
flows across land surface into rivers, streams, lakes, wetlands
 Surface runoff - precipitation does not infiltrate into the
ground or returns to atmosphere by evaporation
 Watershed (drainage) basin – land from which surface
water drains into a specific body of water
 Reliable runoff – amount of surface run off that we can
count on as a source of fresh water from year to year
 1/3 of total
Groundwater Unconfined and Confined
Aquifer
Unconfined Aquifer Recharge Area
Evaporation and transpiration Evaporation
Precipitation
Confined
Recharge
Area
Runoff
Flowing
artesian well
Infiltration
Water
table
Well
requiring
a pump
Stream
Lake
Infiltration
Less permeable
material such as
clay
Fig. 13-3, p. 316
Large and Growing Portion of the World’s
Reliable Runoff Used
 2/3 of the surface runoff: lost by seasonal floods
 1/3 runoff usable – 34% withdrawn now, 70% by
2025 to support increased population growth
 Domestic: 10%
 Agriculture: 70%
 Industrial use: 20%
Fred Pearce – When Rivers Run Dry
 450,000 liters(120 000 gallons) : produce small car
 140 liters (37 gallons) : produce a cup of coffee
 25 bath tubs full of water to produce ONE T-shirt
Freshwater Resources in the US
 More than enough renewable freshwater,
unevenly distributed
 Contaminated by agriculture, industry
 Effect of
 Floods
 Pollution
 Drought
 2007: U.S. Geological Survey projection
 Water hotspots
Water Hotspots in 17 Western U.S. States
Fig. 13-4a, p. 317
water deficit regions
Fig. 13-4b, p. 317
Water Shortages Will Grow……..
 Dry climate
 Drought
 Too many
people using
a normal
supply of
water
 More than 30
countries in
the Middle
East and
Africa
Stress on the World’s Major River Basins
Water Shortages Will Grow……….
 Wasteful use
of water
 China and
urbanization:
2/3rd of the
country face
water
shortages
 Hydrological
poverty- 1.1
billion people
Stress on the World’s Major River Basins
Long-Term Severe Drought Is Increasing
 Causes
 Extended period of below-normal rainfall
 Diminished groundwater due to falling water tables,
climate change, severe drought
 Harmful environmental effects
 Dries out soils
 Reduces stream flows
 Decreases tree growth and biomass
 Lowers net primary productivity and crop yields
 Shift in biomes toward relatively dry conditions such
savannas and deserts
In Water-Short Areas Farmers and Cities
Compete for Water Resources
 2007: National Academy of Science study
 Increased corn production in the U.S. to make
ethanol as an alternative fuel
 Decreasing water supplies
 Aquifer depletion
 Increase in pollution of streams and aquifers
Other crops – soybeans, oil palms, sugar cane
Managing Freshwater Resources…….
 Most water resources
 Owned by governments
 Managed as publicly owned resources
 Veolia and Suez: French companies – water scarcity
,world’s most urgent environmental problem
 Buy and manage water resources – lucrative
 Veolia – water for 108 million in 57 countries
 Successful outcomes in many areas
Managing Freshwater Resources…….
 Bechtel Corporation
 Poor water management in Bolivia -2002
 A subsidiary of Bechtel Corporation - 2007
 Poor water management in Ecuador
 Potential problems with full privatization of water
resources
 Financial incentive to sell water; not conserve it
 Poor will still be left out
Is Extracting Groundwater the Answer ?
 Groundwater that is used to supply cities and
grow food is being pumped from aquifers in some
areas faster than it is renewed by precipitation.
 Aquifers provide – drinking water, 37% of
irrigation water
Water Tables Fall When Groundwater Is
Withdrawn Faster Than It Is Replenished
 India, China, and the United States
 Three largest grain producers
 Over pumping aquifers for irrigation of crops
 half a billion people
 India and China
 Small farmers drilling tube wells
 Effect on water table – falls
 Increasing demands for electricity-coal fired plants
 Saudi Arabia
 70% of it’s drinking water at a high cost-salinization
 Deep Aquifer depletion and irrigation ( estimated to
disappear within 1 to 2 decades)
Irrigation in Saudi Arabia Using an Aquifer
TRADE-OFFS
Withdrawing Groundwater
Advantages
Disadvantages
Useful for drinking
and irrigation
Aquifer depletion
from overpumping
Available year-round
Sinking of land
(subsidence) from
overpumping
Exists almost
everywhere
Renewable if not
overpumped or
contaminated
No evaporation
losses
Cheaper to extract
than most surface
waters
Aquifers polluted for
decades or centuries
Saltwater intrusion into
drinking water supplies
near coastal areas
Reduced water flows
into surface waters
Increased cost and
contamination from
deeper wells
Fig. 13-7, p. 321
Areas of Greatest Aquifer Depletion in the U.S.
Aquifer Depletion in the United States
 Ogallala aquifer: largest known aquifer- lies under 8
mid western states from South Dakota to Texas
 Irrigates the Great Plains
 Water table lowered more than 30m
 Cost of high pumping makes it too expensive to irrigate in
certain areas. Amount of farmland decreased by 11%
 Government subsidies to continue farming deplete the
aquifer further by encouraging the growth of water thirsty
crops
 Biodiversity threatened in some areas
 California Central Valley: serious water depletion
WYOMING
Ogallala World’s
Largest Known
Aquifer
SOUTH DAKOTA
NEBRASKA
COLORADO
KANSAS
NEW MEXICO
OKLAHOMA
TEXAS
Miles
0
100
160
0
Kilometers
Saturated thickness
of Ogallala Aquifer
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)
Fig. 13-10, p. 323
Groundwater Over pumping Has Other Harmful
Effects
 Limits future food production
 Bigger gap between the rich and the poor – expensive
to dig deeper wells, buy large pumps and use more
electricity to drive the pumps. Poor farmers cannot
afford to do this, give up farming and migrate to cities
 Land subsidence – with drawing large amounts of
water causes the sand and rocks in aquifers to collapse
 Mexico City – sunk 10 meters, Beijing, Bangkok
 US – San Joaquin Valley, Baton Rouge, Phoenix
 Sinkholes – large craters that form when the roof of
an underground cavern collapses when groundwater
drained. Can appear suddenly
SOLUTIONS
Groundwater Depletion
Prevention
Control
Waste less water
Raise price of water
to discourage waste
Subsidize water
conservation
Tax water pumped
from wells near
surface waters
Limit number of wells
Set and enforce
minimum stream flow
levels
Do not grow waterintensive crops in
dry areas
Divert surface water
in wet years to
recharge aquifers
Fig. 13-11, p. 324
Harmful Effects of Groundwater Over
pumping
 Groundwater overdrafts near coastal regions
 Salt Water Intrusion - Contamination of the
groundwater with saltwater
 Undrinkable and unusable for irrigation
 Serious – coastal areas of Florida, California,
South Carolina, Georgia, New Jersey , Texas
 Turkey, Manila, Philippines, Bangkok
Rising sea levels from global warming will increase
salt water intrusion and decrease the amount of
ground water available
Are Deep Aquifers the Answer?
 Locate the deep aquifers; determine if they contain
freshwater or saline water.
 Drill a bore hole and measure the electrical resistance of
layers of geological material at different depths. Freshwater
aquifers has higher electrical resistance than saline
 Measurements of the natural radioactive emissions of
gamma rays locates aquifers
 Major concerns
 Geological and ecological impact of pumping water
from them
 Flow beneath more than one country
 Who has rights to it?
Role of Large Dams and Reservoirs ……..
 Main goals of a dam and
reservoir system
 Capture and store runoff
 Release runoff as
needed to control:
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Floods
Generate electricity
Supply irrigation
water
Recreation
(reservoirs)
Advantages and Disadvantages of large
dams and reservoirs
Disadvantages
1.Displaces people
40-80 million people
2.Flooded regions
3.Impaired ecological
services of rivers
4.Loss of plant and animal
species
5.Fill up with sediment
within 50 years
Advantages
1.Increase available
reliable run off
2. Reduce flooding
3. Grow crops in
arid regions
4. Produce energy
800,000 dams world wide
45,000 large dams
22,000 in China
The Ataturk Dam Project in Eastern Turkey on
the River Euphrates
1976
1999
Some Rivers Are Running Dry and Some
Lakes Are Shrinking
 Dams disrupt the hydrologic cycle
 reduce downtown flow to a trickle
 prevent river water from reaching the sea
 only 21 of the 177 rivers run freely to sea from source
 Major rivers running dry part of the year
 Colorado and Rio Grande, U.S.
 Yangtze and Yellow, China
 Indus, India
 Danube, Europe
 Nile River-Lake Victoria, Egypt
 Lake Chad, Africa: disappearing shrunk 96% since 1960
The Colorado River Basin— An Over tapped
Resource
 2,300 km through 7
U.S. states
 From snow melt in the
Rocky Mountains
 14 Dams and reservoirs
 Located in a desert area
within the rain shadow
of the Rocky
Mountains
The Colorado River Basin— An Over tapped
Resource
 Supplies water and
electricity for more
than 25 million people
 Las Vegas ,San Diego,
LA, California’s
Imperial Valley
 Irrigation 15% of the
nation’s crops and
livestock
 Recreation
The Colorado River Basin— An Over tapped
Resource
 Four Major problems
 Colorado River basin
has very dry lands
 Modest flow of water
for its size
 Legal pacts allocated
more water for human
use than it can supply
 Amount of water
flowing to the mouth
of the river has
dropped
Aerial View of Glen Canyon Dam Across
the Colorado River and Lake Powell
 Economic and
ecological catastrophe
 Political and legal battle
over who will get how
much of the region’s
diminished water supply
 Agricultural production
would drop sharply
China’s Three Gorges Dam
 World’s largest hydroelectric dam, built across the
Yangtze
 2 km long, built at a cost of $25 billion
 Produce enough power for 22 large coal-burning
power plants. Reduce China’s dependence on coal
and cut down greenhouse gas emissions
 Hold back the flood waters of the Yangtze which
have killed more than 500,000 in the past 100 years
 Large cargo carrying ships to travel into China’s
interior
 600 km reservoir behind the dam
China’s Three Gorges Dam
 Harmful effects
 Displaces about 5.4 million people
 Built over a seismic fault
Significance?
 Rotting plant and animal matter producing CH4
 Worse than CO2 emissions
 Will the Yangtze River become a sewer?
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Is Transferring Water from One Place to
Another the Answer?
 Water transferred by
 Tunnels
 Aqueducts
 Underground pipes
 California Water Project
 from water rich North to
south
 contention over water
rights
The Aral Sea Disaster
 Large-scale water transfers
in dry central Asia
 1960 on water diverted to 2
feeder rivers to create one of
the world’s largest irrigation
areas- cotton, rice
 Salinity risen 7 fold, average
water dropped by 22 meters
 Lost 89% of water volume
 Wetland destruction (85%),
wildlife(50%) gone
 Fish extinctions and fishing
– 28 of 32 species gone
The Aral Sea Disaster
 Wind-blown salt – up to 500
km away
 Aral sea dust settling on
glaciers in the Himalayas,
causing them to melt at
faster rate
 Water pollution – salt
spreads, kills fish
 Climatic changes – no
thermal buffer, because sea
has shrunk
 Restoration efforts
Ship Stranded in Desert Formed by Shrinkage
of the Aral Sea
China Plans a Massive Transfer of Water
 South-North Water Transfer Project
 Water from three rivers to supply 0.5 billion people
 Completion in about 2050
 Impact
 Economic
 Health
 Environmental
Is Converting Salty Seawater to Freshwater the
Answer?
 Desalination involves removing dissolved salts
from ocean water/brackish water
 Converting salty ocean water to freshwater
 The cost is high, and the resulting salty brine must
be disposed of without harming aquatic or
terrestrial ecosystems.
Removing Salt from Seawater Promising but
Costly
 Desalination
 Distillation : heating saltwater until it evaporates,
leaving behind salts in solid form and condenses as
fresh water
 Reverse osmosis, microfiltration : high pressure
forces salt water through a membrane filter with
pores small enough to remove the salt
 15,000 plants in 125 countries
 Saudi Arabia: highest number
Removing Salt from Seawater Promising but
Costly
 Problems
 High cost and energy footprint – desalination requires
ten times more energy than reverse osmosis
 Pumping large volumes of sea water through pipes and
using chemicals to sterilize the water keeps down algal
growth and kills many marine organisms
 Large quantity of brine wastes that contain lots of salts
and other minerals
 Dumping this brine into nearby coastal waters increases
salinity -threatens aquatic life.
 Disposing on land – contaminates ground and surface
water
 Future economics – water short, wealthy countries
Improved Desalination Technology
 Desalination on offshore ships
 Solar or wind energy to desalinate water cheaply
 Energetech,H2AU (Australia) – energy from ocean
waves drive reverse osmosis
 2005 – GE developing technology
 Better membranes – more efficient separation , less
pressure, less energy
 Develop molecular size nanofilters
 Better disposal options for the brine waste
 Reduce water needs, conserve water
Use Water More Sustainably
 65-70% water people use wasted through evaporation ,
leaks
 Main reason for water waste – low cost to users,
government subsidies
 False message that water is abundant
 Use water more sustainably by cutting water waste to
15%, raising water prices, slowing population growth,
and protecting aquifers, forests, and other ecosystems
that store and release water.
 Life line rates – South Africa
 Lack of government subsidies
Cut water waste in irrigation …………….
 Flood irrigation method delivers far more water than is
needed for crop growth and typically loses 40% of the
water through evaporation, seepage, and run off. This
wasteful method is used on 97% of China’s irrigated land
 More efficient and environmentally sound irrigation
technologies can greatly reduce water waste on farms
Irrigation Systems
 Flood irrigation
 Wasteful
 Center pivot, low
pressure sprinkler
 Low-energy, precision
application sprinklers
 Drip or trickle
irrigation, micro
irrigation
 Costly; less water waste
Developing Countries Use Low-Tech
Methods for Irrigation
 Human-powered treadle pumps to pump groundwater
through irrigation ditches in Bangladesh
 Harvest and store rainwater – running pipes from roof tops,
digging channels to catch rain water and stored – India
 Polyculture and agroforesstry to create a canopy over crops:
reduces evaporation
 Plant deep rooted perennial crop varieties , control weeds,
and mulch fields
 Fog-catcher nets developed in Chile are used to harvest
water
Cut Water Waste in Industry and Homes
 Recycle water in industry – 90% of water used by
industry
 Raise water prices
 Fix leaks in the plumbing systems – stop 10-30% loss
 Use low flush toilets , low flow shower heads
 Use water-thrifty landscaping: xeriscaping
 Use gray water –irrigate lawns, non-edible plants
 Singapore – all sewage water is treated at reclamation
plants for reuse by industry
 Pay-as-you-go water use
Use Less Water to Remove Wastes……
 Can we mimic how nature deals with waste?
 Return the nutrient rich sludge produced by
conventional waste treatment plants to the soil as
fertilizer, instead of dumping the plant nutrients
extracted from waste water treatment plants into water
systems
 Banning the discharge of industrial toxic chemicals
into sewage treatment plants would help to make this
feasible
 Waterless composting toilets that convert human fecal
matter to a small amount of dry and odorless soil-like
humus material that can be removed from a
composting chamber every year or so
Use Water More Sustainably …………..
 “The frog does not drink up the pond in
which it lives”
 Blue revolution – use less water and cut out water
waste to reduce water footprint
Reduce the Threat of flooding …………..
 We can lessen the threat of flooding by protecting
more wetlands and natural vegetation in
watersheds and by not building in areas subject to
frequent flooding.
Some Areas Get Too Much Water from Flooding
 Flood plains – water in a stream overflows it’s normal
channel and spills into an adjacent area
 Highly productive wetlands
 Provide natural flood and erosion control
 Maintain high water quality
 Recharge groundwater
 Benefits of floodplains
 Fertile soils
 Ample water for irrigation
 Nearby rivers for use and recreation
 Flatlands for urbanization and farming
Some Areas Get Too Much Water from Flooding
 Floodplain - water in a stream overflows it’s normal
channel and spills into an adjacent area
 Include highly productive wetlands, provide natural flood
and erosion control, maintain high water quality
Advantages : fertile soil, ample water for irrigation, flatland
suitable for crops , rivers for transportation
Disadvantages: floods kill people and damage property
Removal of water-absorbing vegetation
Draining and building on wetlands
August 2005 – Hurricane Katrina – damage intensified
because of removal of coastal wetlands, lost buffer
Hillside Before and After Deforestation
Living Dangerously on Floodplains in
Bangladesh
 Dense population -147 million people (size of Wisconsin)
 Located on coastal floodplain - slightly above sea level
 Moderate floods maintain fertile soil – rice, thatched
roofs
 Increased frequency of large floods –every 50 years,
 Effects of development in the Himalayan foothills
 monsoon rains now run more quickly
 carry vital topsoil with them
 Destruction of coastal wetlands for fuel wood, farming
and aquaculture
 Result severe flooding from surges
Reduce Flood Risks………..
 Rely more on nature’s systems
 Wetlands
 Natural vegetation in watersheds
 Preserve wetlands and restore ones that have
been damaged
 Rely less on engineering devices
 Dams
 Levees
 Increased possibility of flooding downstream
SOLUTIONS
Reducing Flood Damage
Prevention
Control
Preserve forests on
watersheds
Straighten and
deepen streams
(channelization)
Preserve and restore
wetlands in floodplains
Tax development on
floodplains
Use floodplains primarily
for recharging aquifers,
sustainable agriculture
and forestry
Build levees or
floodwalls along
streams
Build dams
Fig. 13-26, p. 340