water §importance and unique properties. features §covers 71% of the earth’s surface §regulates...

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