Transcript Chapter 13
Chapter 13
Water Conflicts in the Middle East:
Water shortages in the Middle
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
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:
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?
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