Post on 11-Jan-2016
Water
Importance and unique properties
Featurescovers 71% of the Earth’s surface
regulates Earth’s climate
dilutes wastessculpts earth’s
surface,major habitat
Supply97% in oceans
3% fresh water
2.997% in ice caps glaciers
.003% available to us
Watersheds - drainage basins
areas of land that drain into bodies of surface water
water flowing off land into these bodies is called surface runoff
Hydrologic Cycle
natural recycling and purification process
plenty of fresh water, if not overloaded with degradable and non-degradable material
divide world into “haves” and “have nots”
Solar powered hydrologic cycle
Evaporationtranspirationcondensationprecipitationrunoffpercolationgroundwaterwater table
Surface water
precipitation that does not soak into the ground or return to the atmosphere by evaporation
streams, lakes, wetlands, reservoirs
Groundwater
precipitation infiltrates the ground and fills pores in soil and rocks
zone of saturation - all available soil and rock spaces filled by groundwater
Water Table
upper surface of zone of saturation poorly demarcated between saturated soil and rock and unsaturated soil and rock
falls in dry weather and rises in wet weather
Aquifers
groundwater which flows through water saturated layers of sand, gravel, bedrock
replenished naturally by precipitation(natural recharge)
slow moving underground lakes
Diagram- aquiferMajor reservoirs of groundwater
consolidated forms
solid rock with groundwater in cracks
unconsolidated forms
sand,gravel,loose earth
amount of water depends on packing
Cone of depressionwithdrawal rate of aquifer exceed natural recharge rate ,
water table around withdrawal well lowered
creates a waterless volume
any pollution discharged onto land above will be pulled directly into well
Total Water Use
Amounts - US examples
100,000 = 1 car1000 gal = 1lb of aluminum800 gal = 1 LB of beef26 gal = 2.2 lbs. paperAll nuclear plants require more
water than Lake Eerie
Use of watermostly to irrigate crops(69%)
energy production- 23%
industrial usage highest in Europe and N.America (US)
Cause …freshwater shortages
dry climatedrought -water stressdesiccation-overgrazing and
deforestationAfrica,Middle East .S.Asia
Drought
at least 80 countries (40%) of world population experience year long droughts
since 1970’s - more than 24,000 dead
Water - political issue150 of world’s 214 river systems shared by 2 countries
another 50 by 3-10
nations
Water Resources in US - Case StudyEast - energy
production, cooling, manufacturing -flooding, occasional shortages, pollution
West - irrigation ,water tables dropping,
groundwater depleted faster than recharging
Increased water supply
build dams and reservoirswithdraw groundwaterincrease water efficiency
Living…..
Developed -favorable climate ,bring in water from another watershed
Developing - must settle where water is available , borrow money to build dams and reservoirs
Constructing dams/reservoirs
water stored in large reservoirsused for hydroelectric power,
irrigate land downstream, control flooding, recreation
Examples - India
efficient irrigation let country become self sufficient in food, environmental problems with 1500 dam projects
still going ahead with 20 new dams in Gujerat - displace about 1 million people
India
Example -China
Three Gorges Project, world’s largest hydroelectric project, 370 mile reservoir ; power to 150 million Chinese,energy produced =18 nuclear power plants reduce dependence on coal, hold back Yangtze
flood 800 factories, displace 1.4 million people
Peoples Republic of China
Examples-Japan
inflatable small rubber dams, 1000 filled with air
can be deflected to allow accumulated silt to flow downstream
Case Study : Aswan Dam
Advantages - supplies electricity, irrigation
Disadvantages- silt accumulates, schistosomiasis
$100 million spent - fertilizersexpensive barrier damsfishing industry collapsed
Case study : Watershed Transfer-California
maze of giant dams, pumps, aqueducts
transports water from N California to arid agricultural areas
irrigation for cotton, alfalfa uses as much water residential
needs of all 30 million Californians
Aqueducts
Case Study : James Bay Watershed Transfer
Quebec’s James and Hudson Bays$60 billion, 50 year scheme to provide
electricityphase I completed, phase II indefinitely
postponed
Case Study : Aral Sea
regional ecological disaster
shrinking and increased salinity as a result of irrigation water being diverted
all fish dead salt, dust ,pesticide
residues carried by wind -salt rain
Withdrawing groundwater - US
being withdrawn at 4 times replacement level
1/2 of US drinking water and 40% of irrigation water from aquifers
Ogallala aquifer
Aquifer depletion
Saudi Arabia, Northern China, Northern Africa
withdrawal 10 times the recharge
Over use (fig 17- 18)
aquifer depletion aquifer subsidence
intrusion of salt water-water table lowered, normal interface between fresh and salt water moves inland
How can we slow this
not plant water thirsty crops in dry areas
develop crop strains that require less water
waste less irrigation water
Desalination
removal of dissolved salts from ocean or brackish water
7500 plants in 120 countries- 0.1% fresh water
distillation = heating salt water until it evaporates,salt left as solid
reverse osmosis - salt water pumped through thin membrane,salt left behind
Disadvantages
enormous amounts of electricity required
distribution from coastal plants expensive
dumping of concentrated brine, increases local salt concentration
Cloud Seeding
injecting large rain cloud with chemicals - silver iodide
water droplets in cloud clump around the chemical particles
forms icedrops to earth as precipitation
Disadvantages
non availability of rain cloudscloud seeding chemicals
introduced into soil and water systems
ownership of water in clouds
Solutions
using water efficiently
Solutions
using water efficiently
Why ?
Reduce usage of waste water plants and septic systems
decrease pollution of surface water
reduce number of dams that destroy wildlife, displace people
slows depletion of aquifers
Curbing waste
evaporation, leaks, other losses
Reason for waste
artificially low water pricesexternal costs not included in
monthly bills
Reducing irrigation losses
69% of water usage is for irrigation,
2/3 rd of this is wasted
Irrigation
3 different kinds
Gravity flow
water from aqueduct or nearby river
50 - 60 % efficiency
leveling of fields, surge flooding, capture and reuse runoff
Center Pivot
water pumped from underground and sprayed from mobile boom with sprinklers
70-80% efficiency
Drip irrigationabove or below
ground pipes or tubes deliver water to individual plant roots
80 - 90% efficiency
Less wastage - Industry
use recycled watermachines designed to save waterJapan Israel
Most Wastage - Residences
water - used to flush toilets, wash hands, baths
green lawns in arid areas
Xeriscapingvegetation
adapted to dry climate
30-80% less water used
Solutions - Appendix 5
water meterrepair leaky pipeslow flush toilets and showerheadsgray water for irrigation
Sustainable Usage - Case study
Columbia River BasinWorld’s largest hydroelectric
systemmore than 100 damselectricity prices - 40% lowerinterferes with salmon life cycles
Salmon ranching
artificial hatcheriesgenetic inbreedingworld’s largest program for
ecosystem rehabilitationcost - $2 billionTime - 2 decades
Florida Everglades restoration
case study
Everglades
slow moving river50 miles wide, 6 inches deepflows south through Everglades
National Park into Estuary at Florida Bay (Fig 17 -25)
World’s largest marshland
haven for 14 endangered or threatened species
(American alligator, Florida panther)
aquifer recharge, precipitation system
Problems - development - page 476
straightening Kissimmee rivertremendous environmental
impact
What can we do ?
Restore original path of Kissimmee
reclaim areas of wetlands will cost $2 billion at the lower
estimate