1. Chapter 13 Water: A Limited Resource

2. Overview of Chapter 13 Importance of Water
Hydrologic Cycle
Water Use and Resource Problems
Too Much Water
Too Little Water
Water Problems in US and Canada
Global Water Problems
Sharing Water Resources
Water Management
Providing Sustainable Water Supply
Water Conservation

3. Importance of Water Cooking Washing Use large amounts for:
Agriculture
Manufacturing
Mining
Energy production
Waste disposal
Use of freshwater is increasing

4. Properties of Water Composed of 2 Hydrogen and 1 oxygen
Exists as solid, liquid or gas
High heat capacity – absorbs a lot of solar energy without increasing in temperature much.
Earth’s temperature matches temperature for water as a liquid.
“universal solvent” allows dissolved gases and minerals in water, including pollutants
Colder water is more dense until 4 Celsius, then becomes less dense (ice floats and allows living things beneath)

5. Hydrologic Cycle

6. Only 2.5% of water on earth is freshwater 2% is ice!
Distribution of Water
Only 2.5% of water on earth is freshwater
2% is ice!
Only ~0.5% of water on earth is available freshwater

7. Check for understanding
4 - I can explain to my peers at least 5 properties of water and how water is distributed on earth.
3 - I understand 3-4 properties of water and how water is distributed on earth.
2 - I can explain at least 2 properties of water and how water is distributed on earth.
1 - huh? I know 1 property of water.

8. Freshwater Terminology
Surface water
Precipitation that remains on the surface and does not seep into soil
Runoff
Movement of surface water to lakes, rivers, etc.
Watershed (drainage basin)
Land area that delivers water into a stream or river system
Groundwater
Freshwater under the earth’s surface stored in aquifers
Aquifer
Underground caverns and porous layers of sand, gravel and rock in which groundwater is stored
Unconfined and confined (artesian)
Water table

10. Freshwater Aquifer

14. Check for understanding
4 - I can explain to my peers the difference between a confined and unconfined aquifer, what a water table is and the difference between groundwater, surface water, runoff, and a watershed is.
3 - I understand the difference between a confined and unconfined aquifer, but might not fully understand the difference in one of the following terms: a water table, groundwater, surface water, runoff, and watershed
2 - I am confused about at least 2 of the above terms
1 - I am confused about at least 3 of the above terms

15. Water Use and Resource Problems
Fall into Three Categories
Too much water
Too little water
Poor quality/contamination (discussed later)

16. Water Use Mostly for irrigation for agriculture: 68% Industry
Even arid (deserts) & semiarid land grow crops with enough H2O
Asia uses most
Industry
Domestic/municipal: 8.6%
xeriscaping

17. Too Much Water Flooding
Both natural and human-induced. Causes???
Modern floods are highly destructive because humans:
Remove water-absorbing plant cover from soil
Construct buildings on floodplains
Floodplain
Area bordering a river channel that has the potential to flood
Naturally leave behind organic matter in soil – good.
Flood consequences???

18. Urban vs. Pre-Urban Floodplains

19. Floodplain Government restrictions on building
Levees can fail
Rather than rebuild levees adjacent to rivers, experts suggest allowing some flooding of floodplains during floods
Less damage if flooded
Replenish soil
Save money

20. Left: Traditional levees adjacent to river
Right: Suggested levee style, set back from river

21. NEW ORLEANS: HURRICANE KATRINA: AUGUST 2005

22. Case-In-Point Floods of 1993: Mississippi River
Worsened due to:
Draining wetlands for farms and homes
2. Building levees (can force more surge upstream)
3. Building on floodplains
Similar to New Orleans

23. Check for understanding
4 - I can explain to my peers the causes and consequences of flooding and the problems associated with flooding and why modern societies suffer more damage from them.
3 - I understand the causes and consequences of flooding and the problems associated with flooding and why modern societies suffer more damage from them
2 - I need to reread my notes, but I understand
1 - I don’t fully understand flooding.

24. Too Little Water
Typically found in arid land (40% of population – Africa/Asia)
Women may walk to get water instead of school
Problems
Drought
Remove native water absorbing plants and replace with crops/livestock overgraze  more runoff, less water in soil
Overdrawing water
for irrigation purposes  saltier estuaries, dried wetlands (loss of bird breeding grounds)

25. Too Little Water Problems (continued) Aquifer depletion
Subsidence – sinking of land on porous rock
Sinkholes – eroded limestone
Saltwater Intrusion (coasts)

26. Problems (continued)
Aquifer depletion
Saltwater Intrusion (coasts)

27. Water Problems In US US has a plentiful supply of freshwater
Many areas have a severe shortages
Geographical variations
Seasonal variations

28. Water Problems in US Water shortages in West and Southwest
Historically for irrigation, now more water for industrial and municipals due to increased population
Water is diverted and transported via aqueducts

29. Water Problems in US Surface Water
Mono Lake (Eastern CA)
Rivers and streams that once fed this lake are diverted to Los Angeles (275mi away)
Becoming highly saline due to water diversion  disrupt food chain
Court ordered water diversion reduction
LA efforts to use more reclaimed water
Colorado River Basin
Provides water for 27-million people – Colorado, California, Arizona, into Mexico
Numerous dams for Hydropower; also create resevoirs
Colorado River no longer reaches ocean

31. HOOVER DAM: BETWEEN ARIZONA AND NEVADA

33. SALMON FISH LADDER

34. Colorado River bed in Mexico

35. Check for understanding
4 - I can explain to my peers how water diversion and dams can disrupt the amount of water in effected areas.
3 - I understand how water diversion and dams can disrupt the amount of water in effected areas
2 - I need to reread my notes, but I understand
1 - I don’t fully understand the impact of water diversion projects and dams.

36. Water Problems in US and - Groundwater
Aquifer Depletion – especially Arizona, California, High Plains

37. Case study: Ogallala Aquifer
High Plains
Largest groundwater in world
Uses 30% of irrigation water in US – corn, wheat, soybean, livestock (6% of land)
Water table down 100 ft in some areas (rate of recharge less than rate of extraction) cost money to deepen wells, lose $ on dead crops

38. Global Water Problems
Amount of freshwater on planet CAN meet human needs
BUT, it is unevenly distributed and some places lack stable runoff

39. Global Water Problems 1. Water and Climate Change
Climate change affects the type and distribution of precipitation
Potential issues:
Reduced snowfall will impact water resources downstream
Sea level rise will cause saltwater intrusion into drinking water supplies

40. Global Water Problems 2. Drinking Water Problems
Many developing countries have insufficient water to meet drinking and household needs (1.1 billion lack safe water, 2.6 billion no good disposal of wastewater/fecal waste)  illness Ex: Cholera
Ex: Sahel region of Africa
Help: World Bank, US Agency for International Development (AID)

41. 3. Population Growth
Increase in population means an increase in freshwater requirements
Limits drinking water available
Limits water available for agriculture (food)
Ex: Northern China – Yellow River, Indus River in Pakistan, Mexico (aquifer)

42. Global Water Problems 4. Sharing Water Resources Among Countries
Rhine River Basin (right)
Countries upstream discharged pollutants into river
Countries downstream had to pay to clean the water before they could drink it
Aral Sea
Kazakhstan and surrounding countries
Water diversion for irrigation has caused sea to become too saline  decreased biodiversity

43. Aral Sea
1967
1997

44. Check for understanding
4 - I can explain to my peers how climate change, pathogens, a growing population, and water diversion can reduce water availability.
3 - I understand how climate change, pathogens, a growing population, and water diversion can reduce water availability
2 - I need to reread my notes, but I understand
1 - I don’t fully understand the impact of climate change, pathogens, a growing population, and water diversion can have on water availability.

45. Global Water Problems
5. Potentially Volatile International Water Situations
Jordan River – supplies many middle Eastern countries
Nile River (NE Africa) – Sudan and Ethiopia using more (increased population) and affecting Egypt’s supply

46. Water Management
FUN FACT: For every kilogram of animal protein produced, livestock are fed nearly 6 kg of plant protein. Every kilogram of beef produced takes 100,000 liters of water. A kilogram of wheat requires 900 liters of water.

47. Water Management
Main Goal: Provide sustainable supply of high-quality water
Requires humans to use resource carefully
Dams and Reservoirs
Water Diversion Projects
Desalinization
THREE GORGES DAM - CHINA

48. Dams and Reservoirs Benefits: Disadvantages
Ensure year-round supply of water with regulated flow
Generate electricity
Provide recreational activities
Disadvantages
Alter the ecosystem
Reduce sediment load downstream
Displace humans
Disrupt salmon migration for breeding

49. Dams and Reservoirs Glen Canyon Dam To rectify situation
Regulated flow has changed ecosystem
To rectify situation
Canyon has been flooded several times
Small floods compared to natural floods
Still helps rebuild habitat

50. Water Diversion Projects
Diverting water via aquaducts/canals
Ex: Mono Lake, Aral Sea
Controversial and expensive
ARAL SEA: Kazakhstan-Uzbekistan border

51. Desalinization Removal of salt from ocean or brackish water
Two methods:
Distillation- salt water is evaporated, and water vapor is condensed into freshwater (salt left behind)
Reverse Osmosis- involves forcing salt water through a membrane permeable to water, but not salt
Very expensive due to large energy input
What to do with left over salt?

52. Check for understanding
4 - I can explain to my peers how dams/reservoirs, desalinization, and water diversion makes water available for human use and the consequences of each.
3 - I understand how dams/reservoirs, desalinization, and water diversion makes water available for human use and the consequences of each
2 - I need to reread my notes, but I understand
1 - I don’t fully understand how dams/reservoirs, desalinization, and water diversion makes water available for human use and the consequences of each

53. Water Conservation Reducing Agricultural Water Waste
Drip Irrigation- irrigation that conserves water by piping to
crops through sealed systems
Also called microirrigation or
trickle irrigation

54. Water Conservation Reducing Industrial Water Waste
EX: paper, petroleum, food processing
Stricter laws (and enforcement of those laws) provide incentive to conserve water
EX: Recycling water within the plant
Water scarcity (in addition to stricter pollution control requirements) will encourage further industrial recycling
Potential to conserve water is huge!

55. Water Conservation
Reducing Municipal Water Waste : reduce, reuse, recycle
Gray Water (reclaimed water)
Can be used to flush toilets, wash car or water lawn
Water saving household fixtures
Raising costs to reflect real cost
Government incentives

56. Conserving at Home Install water-saving shower heads and faucets
Install low-flush toilets
Fix leaky fixtures
Purchase high efficiency appliances – dishwasher/washing machine
Modify personal habits
Shorter showers, showers not baths
Use the dishwasher instead of washing by hand

58. Check for understanding
4 - I can explain to my peers ways for agriculture, industry, and homes can conserve water.
3 - I understand ways for agriculture, industry, and homes can conserve water
2 - I need to reread my notes, but I understand
1 - I don’t fully understand ways for agriculture, industry, and homes can conserve water.