1. Living in the Environment
Water Resources
G. Tyler Miller’s
Living in the Environment
13th Edition
Chapter 14
Dr. Richard Clements
Chattanooga State Technical Community College
Modified by Charlotte Kirkpatrick

2. Key Concepts The physical properties of water
Availability of fresh water
Methods of increasing freshwater supplies
Using water more efficiently
Problems associated with flooding

3. Water’s Unique Properties
Hydrogen bonding: strong forces of attraction
between water molecules. Main reason for water’s unique
properties
Liquid over wide temperature range: liquid in most climates on earth
Changes temperature slowly: high heat capacity; translates into an excellent coolant
High heat of evaporation: requires large amounts of heat to evaporate and therefore is an effective cooling process.

4. Water phase diagram
Sublimation is the phase change as a substance changes from a solid to a gas without passing through the intermediate state of a liquid.
Deposition is the phase change as a substance changes from a gas to a solid without passing through the intermediate state of a liquid.
TRIPLE POINT - The temperature and pressure at which the solid, liquid, and gas phases exist simultaneously.
CRITICAL POINT - The temperature above which a substance will always be a gas regardless of the pressure.
NOTE:
The solid phase is more dense than the liquid phase. Except in water
The line between the solid and liquid phases is a curve of all the freezing/melting points of the substance.
The line between the liquid and gas phases is a curve of all the boiling points of the substance.
Freezing Point - The temperature at which the solid and liquid phases of a substance are in equilibrium at atmospheric pressure.
Boiling Point - The temperature at which the vapor pressure of a liquid is equal to the pressure on the liquid.
Normal (Standard) Boiling Point - The temperature at which the vapor pressure of a liquid is equal to standard pressure (1.00 atm = 760 mmHg = 760 torr = kPa)

5. Generic Heating and Cooling Curve
                                                                               
Freezing is the phase change as a substance changes from a liquid to a solid.
Melting is the phase change as a substance changes from a solid to a liquid.
Condensation is the phase change as a substance changes from a gas to a liquid.
Vaporization is the phase change as a substance changes from a liquid to a gas.

6. Water’s Unique Properties
Great dissolving power: dissolves many things well and this makes it a good dilution agent and easily polluted
pH: maintains balance between acids and bases
Water filters UV radiation: protects aquatic organisms
Adhesion and cohesion: due to the H-bonds; allows for water molecules to pull together tightly (cohesion) and for high wetting ability of solids (adhesion)
Expands when it freezes: unlike other liquids water expands when it freezes allowing a lake to freeze over from the top down

7. Supply of Water Resources
Freshwater
(2.6% of all water)
Readily accessible freshwater
Biota
0.0001%
Groundwater (unaccessible)
0.592%
Lakes
0.007%
Rivers
0.0001%
0.014%
Ice caps
and glaciers
1.984%
Soil
moisture
0.005%
Atmospheric
water vapor
0.001%
Fig p. 314

8. Readily accessible fresh water
Supply of Water Resources
All water
Fresh water
Readily accessible fresh water
Groundwater
0.592%
Biota
0.0001%
Lakes
0.007%
Rivers
0.0001%
Lakes
0.007%
2.6%
0.014%
Atmospheric
water vapor
0.001%
Oceans and
saline lakes
97.4%
Ice caps
and glaciers
1.984%
Soil
moisture
0.005%
Oceans and saline lakes
97.4%
Ice caps and glaciers
1.984%
Soil moisture
0.005%
Figure 14-2 Page 314

9. Ground Water/Water Cycle
Fig p. 315
Evaporation and transpiration
Evaporation
Stream
Infiltration
Water table
Unconfined aquifer
Confined aquifer
Lake
Well requiring a pump
Flowing
artesian well
Runoff
Precipitation
Confined
Recharge Area
Aquifer
Less permeable material
such as clay
Confirming permeable rock layer

10. Surface Water
Surface runoff:. precipitation that does not infiltrate into the ground or return to the atmosphere by evaporation/transpiration
Reliable runoff: Runoff that is not lost due to seasonal floods.
Watershed (also known as a Drainage Basin): a region from which water drains into a stream, lake, reservoir, wetland, or other body of water.

11. Ground Water/Water Cycle
Groundwater: precipitation that infiltrates the ground and percolates downward through voids (pores, fractures, crevices, and other spaces) in soil and rock. Voids are completely filled some depth below in the zone of saturation.
Water Table: the top of the zone of saturation
Zone of aeration: above the water table where soil may be moist but not saturated

12. Ground Water/Water Cycle
Aquifer: porous water saturated layers of sand, gravel or bedrock in which ground water flows.
Recharge area: any are of land in which water passes downward or laterally into an aquifer
Natural recharge: when aquifers are replenished by precipitation that percolates downward through soil and rock. May be lateral recharge as well.
Groundwater moves from high to low elevation and and pressure at about 1m/yr.

13. Ground Water/Water Cycle
Fig p. 315
Evaporation and transpiration
Evaporation
Stream
Infiltration
Water table
Unconfined aquifer
Confined aquifer
Lake
Well requiring a pump
Flowing
artesian well
Runoff
Precipitation
Confined
Recharge Area
Aquifer
Less permeable material
such as clay
Confirming permeable rock layer

14. Water Use: increased ninefold and per capita withdrawal has quadrupled with irrigation the largest increase since 1900.

15. Use of Water Resources Worldwide use:
Humans use more than half of the reliable runoff: 35% is used directly and the other 20 % is left in streams to transport goods by boats, dilute pollution and sustain fisheries and wildlife
Worldwide use:
Agriculture: 70% (irrigate 18% of world’s cropland and produce 40% of world’s food)
Industry: 20%
Domestic: 10%

16. Use of Water Resources
Figure 14-5 Page 316
United States
China
Agriculture
41%
Agriculture 87%
Power
cooling
38%
Public 6%
Industry 7%
Industry 11%
Public 10%
Largest use at 4800 liters/day (1280 gal./day) per person

17. Average annual precipitation (centimeters)
Less than 41
41-81
81-22
More than 122
Acute shortage
Adequate supply
Shortage
Metropolitan regions with population greater than 1
million

18. Water Used to Produce Some Common Agricultural and Manufactured Products

19. Too Little Water (causes)
Dry climate (see fig. 6-7 pg. 116)
Drought: 21 days or longer in which precipitation is at least 70% lower and evaporation is higher than normal
Dessication: drying of the soil caused by overgrazing and deforestation
Water stress: low per capita availability of water caused by increasing numbers of people relying on limited runoff levels. Per person reliable runoff below 1700 cubic meters/year
Water Scarcity: less than 1000 cubic meters/year per person

20. Dry climates

21. Water Stress: based on amount available with amount used by humans

22. How Can We Increase Freshwater Supplies
Build dams and reservoirs to store runoff
Bring in surface water from another area
Withdraw groundwater
convert salt water to freshwater (desalination)
Waste less water
import food to reduce water use
In developed countries we live where it is nice and bring water in
In developing countries they must settle where the water is

23. Using Dams and Reservoirs to Supply More Water
Large losses
of water through
evaporation
Flooded land destroys forests or cropland and
displaces people
Downstream flooding is reduced
Downstream cropland and
estuaries are deprived of
nutrient-rich silt
Reservoir is useful for recreation and fishing
Can produce cheap electricity (hydropower)
Migration and spawning of some fish are disrupted
Provides water
for year-round
irrigation of
cropland
Fig p. 319

24. Dams and Reservoirs
Main purpose: controlling floods and producing hydroelectric power and supplying water for irrigation. Reservoirs also provide recreational activities.
U.S. has more than 70,000 dams controlling a bout half of the country’s entire river flow.
This often impairs the important ecological services that rivers provide

25. **Know case studies on pp. 320-322
Dams and Reservoirs
Many rivers have been so controlled that the downstream flow is reduced to a trickle and many never reach the ocean/sea before drying out. Especially in arid regions. Ex. Colorado River, Rio Grande, Yellow, Nile, Ganges, Indus, Amu Darya and Syr Darya.
Some countries have taken steps to remove old, dangerous, or environmentally harmful dams
**Know case studies on pp

26. Transferring Water from One Place to Another
Watershed transfer: transfer water from water rich area to water poor area. A variety of tunnels, aqueducts, and underground pipes and pumps can transfer stream runoff collected by dams and reservoirs.
Very visual example of the environmental principle of “you can’t do just one thing”.
Largest is the CA. Water Transfer Project: 75% of the water is in the north yet, 75% of the population is in the south. Other ex. Arizona and James Bay water transfer projects (know case studies p )

27. Transferring Water from One Place to Another
North Bay
Aqueduct
South Bay
California Aqueduct
CALIFORNIA
NEVADA
UTAH
MEXICO
Central Arizona
Project
Colorado River
Los Angeles
Shasta Lake
Sacramento
Fresno
Phoenix
Tucson
ARIZONA
Colorado
River
San Francisco
San Diego
Fig /14-14 p. 323

28. California Water Resources
                                                                                                                                                                                                                          
Blue: Rivers
Red: State water Projects
Yellow: Federal water projects
Green: Local water projects

29. Tapping Groundwater Removed as needed year-round No evaporation losses
Often less expensive than taping from streams
Potential Problems!

30. Problems with Using Groundwater
Water table lowering (See Fig p. 326)
Due to excessive extraction the water table can be lowered as a cone of depression occurs.
Original
water table
Initial water table
Cone of
depression
Lowered
water table

31. Problems with Using Groundwater
Subsidence: Sinking of land when groundwater is withdrawn
Depletion from groundwater overdraft
High
High
Moderate
Moderate
(See Fig p. 326)
Minor or none
Minor or none

32. Problems with Using Groundwater
Saltwater intrusion (See Fig p. 328)
Major irrigation
well
Well contaminated
with saltwater
Water table
Sea Level
Salt
water
Fresh
groundwater
aquifer
Interface
Interface
Normal
Interface
Saltwater
Intrusion
Chemical contamination
Reduced stream flows

33. Water Mining
Water pumping at high rates that exceed the natural rate of recharge.
This unsustainable over pumping of aquifers produces about 8% of the world’s grain harvest. This is causing water tables to fall.
About 480 million of the world’s people are being fed with grain produced with eventually unsustainable water mining from aquifers.

34. Water Mining
Overpumping has increased since 1950 due to more powerful electric and diesel pumps
It limits future food production as well as
Increasing the gap between rich and poor

35. Converting Salt Water to Fresh Water and Making it Rain
Distillation desalination
Reverse osmosis desalination
Desalination is very expensive
Cloud seeding

36. Using Water More Efficiently
Reduce losses due to leakage
Reform water laws
Improve irrigation efficiency (Fig p. 330)
Improving manufacturing processes
Water efficient landscaping
Water efficient appliances

37. Saving water in industry, businesses and residences
• Redesign manufacturing processes
• Landscape yards with plants that require little water
• Use drip irrigation
• Fix water leaks
• Use water meters and charge for all municipal
water use
• Raise water prices
• Require water conservation in water-short cities
• Use water-saving toilets, showerheads, and front-
loading clothes washers
• Collect and reuse household water to irrigate lawns
and nonedible plants
• Purify and reuse water for houses, apartments, and
office buildings
Figure Page 331

38. Too Much Water: Floods Natural phenomena
Aggravated by human activities
Renew and replenish
Reservoir
Dam
Levee
Flood
wall
Floodplain
Fig p. 332

39. Solutions: Achieving a More Sustainable Water Future
Efficient irrigation
Water-saving technologies
Improving water management

40. Irrigation Techniques
Gravity Flow
(efficiency 60% and 80% with surge valves)
Water usually comes from an
aqueduct system or a nearby river.
Drip Irrigation
(efficiency 90-95%)
Above- or below-ground pipes
or tubes deliver water to
individual plant roots.
Center Pivot
(efficiency 80% with low-pressure
sprinkler and 90–95% with
LEPA sprinkler)
Water usually pumped from
underground and sprayed from
mobile boom with sprinklers.
Figure Page 330

41. Agricultural changes to increase water supply
Lining canals bringing water to irrigation ditches
Leveling fields with lasers
Irrigating at night to reduce evaporation
Using soil and satellite sensors and computer systems to monitor soil moisture and add water only when necessary
Polyculture
Organic farming
Growing water-efficient crops using drought- resistant and salt-tolerant crop varieties
Irrigating with treated urban waste water
Importing water-intensive crops and meat
Agricultural changes to increase water supply
Figure Page 331

42. Encouraging Sustainable Use of water
Not depleting aquifers
Preserving ecological health of aquatic systems
Preserving water quality
Integrated watershed management
Agreements among regions and countries sharing surface water resources
Outside party mediation of water disputes between nations
Marketing of water rights
Wasting less water
Decreasing government subsides for supplying water
Increasing government subsides for reducing water waste
Slowing population growth
Encouraging Sustainable Use of water
Figure Page 336