1. Water Resources Chapter 13

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  Liquid over wide temperature range  Changes temperature slowly  High heat of evaporation  Great dissolving power  pH  Adhesion and cohesion  Expands when it freezes

4. Freshwater Is an Irreplaceable Resource That We Are Managing Poorly Earth as a watery world: 71% Earth as a watery world: 71% 3% of earths water is freshwater 3% of earths water is freshwater Freshwater availability: 0.024% Freshwater availability: 0.024% Poorly managed resource – low cost encourages waste. Poorly managed resource – low cost encourages waste. Hydrologic cycle – cycle collects, purifies, recycles, and distributes the world’s freshwater supply Hydrologic cycle – cycle collects, purifies, recycles, and distributes the world’s freshwater supply

5. Supply of Water Resources

6. Surface Water  Surface runoff - precipitation that doesn’t infiltrate the ground or evap. into atmosphere. Flows Into streams, lakes, oceans, etc.  Surface runoff - precipitation that doesn’t infiltrate the ground or evap. into atmosphere. Flows Into streams, lakes, oceans, etc.  Reliable runoff 1/3 of surface runoff that can Be counted on as a stable source of H 2 O  Reliable runoff 1/3 of surface runoff that can Be counted on as a stable source of H 2 O  Watershed (Drainage basin) - region from which Water drains into a stream, lake, reservoir, etc.  Watershed (Drainage basin) - region from which Water drains into a stream, lake, reservoir, etc.

7. Fig. 13-3, p. 316 Unconfined Aquifer Recharge Area Precipitation Evaporation and transpiration Evaporation Confined Recharge Area Runoff Flowing artesian well Well requiring a pump Stream Infiltration Water table Lake Infiltration Unconfined aquifer Less permeable material such as clay Confined aquifer Confining impermeable rock layer Hydrologic Cycle & Groundwater

8. Ground Water- 3. Zone of Saturation - below surface, voids are completely filled with water 1.Zone of aeration - Lies above water table. Rock and soil contain air and may be moist, but not saturated with water. 2. Water Table - at top of zone of sat. Falls in dry weather, rises in wet weather. 4. Aquifers - porous, water-saturated layers of sand gravel or bedrock through which groundwater flows.

9. AQUIFERS Recharge area- area of land through which water passes downward or laterally into an aquifer. Recharge area- area of land through which water passes downward or laterally into an aquifer. Movement is slow ( about 1 meter per year) Natural Recharge - Replenished naturally by precipitation that percolates downward (by gravity) or laterally (by pressure) Natural Recharge - Replenished naturally by precipitation that percolates downward (by gravity) or laterally (by pressure) Can be used as a source of water for human consumption. Provide ¼ of the worlds water. Can be used as a source of water for human consumption. Provide ¼ of the worlds water.

10. Use of Water Resources  Humans use about 54% of reliable runoff  Agriculture – 70%  Industry – 20% Fig. 15-4 p. 309 United States Industry 11% Public 10% Power cooling 38% Agriculture 38% Worldwide:

11. Affluence requires large amounts of water Water it takes to produce: -A small car = 120,000 gallons -A cup of coffee = 37 gallons -A typical t-shirt = 1,250 gallons

12. Too Little Water  Dry climate  Drought  Desiccation – drying of exposed soil  Water stress – low per capita availability of water  Water stress – low per capita availability of water

13. Fig. 13-4a, p. 317 Average annual precipitation (centimeters) 41–81 More than 122 Less than 41 81–122

14. Too Little Water Why? Some rivers etc. are far from populated areas Precipitation is seasonal Poverty limits safe drinking water

15. Fig. 13-6, p. 319 Europe Asia North America Africa South America Australia Stress: High None Natural Capital Degradation: Stress on the World’s Major River Basins

16. Long-Term Severe Drought Is Increasing Causes Causes Extended period of below-normal rainfall Extended period of below-normal rainfall Diminished groundwater Diminished groundwater Harmful environmental effects Harmful environmental effects Dries out soils Dries out soils Reduces stream flows Reduces stream flows Decreases tree growth and biomass Decreases tree growth and biomass Lowers net primary productivity and crop yields Lowers net primary productivity and crop yields Shift in biomes Shift in biomes

17. In Water-Short Areas Farmers and Cities Compete for Water Resources 2007: National Academy of Science study 2007: National Academy of Science study Increased corn production in the U.S. to make ethanol as an alternative fuel is causing: Decreasing water supplies Decreasing water supplies Aquifer depletion Aquifer depletion Increase in pollution of streams and aquifers Increase in pollution of streams and aquifers

18. Who Should Own and Manage Freshwater Resources? Read p. 320 – 321 Read p. 320 – 321 1.Consider the many water management models 2.Discuss pros and cons of private water ownership compared to government.

19. Tapping Groundwater - advantages:  Year-round use  No evaporation losses  Often less expensive

20. Ground Water

21. Aquifers- porous water- saturated layers of underground rock Recharge slowly Water table moves down in dry weather

22. Confined aquifers are under pressure

23. Major irrigation well Well contaminated with saltwater Saltwater Intrusion Normal Interface Fresh groundwater aquifer Interface Salt water Sea Level Water table Saltwater intrusion:

24. Problems with Using Groundwater  Water table lowering  Depletion  Subsidence  Saltwater intrusion  Chemical contamination  Reduced stream flows See Case Study p. 327

25. Subsidence Initial water table Cone of depression Original water table Lowered water table

26. WYOMINGSOUTH DAKOTA NEBRASKA COLORADO KANSAS OKLAHOMA NEW MEXICO TEXAS 0100 Miles Kilometers 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) 0160 Slow recharge= One time withdrawal Government subsidies to continue farming deplete the further Shrinking Ogallala Aquifer

27. Fig. 13-7, p. 321 TRADE-OFFS Withdrawing Groundwater AdvantagesDisadvantages Useful for drinking and irrigation Aquifer depletion from overpumping Available year-round Sinking of land (subsidence) from overpumping Exists almost everywhere Aquifers polluted for decades or centuries Renewable if not overpumped or contaminated Saltwater intrusion into drinking water supplies near coastal areas No evaporation losses Reduced water flows into surface waters Cheaper to extract than most surface waters Increased cost and contamination from deeper wells

28. Fig. 13-11, p. 324 SOLUTIONS Groundwater Depletion PreventionControl Waste less waterRaise price of water to discourage waste Subsidize water conservation Tax water pumped from wells near surface waters Limit number of wellsSet and enforce minimum stream flow levels Do not grow water- intensive crops in dry areas Divert surface water in wet years to recharge aquifers

29. Deliver nutrients to the sea sustain coastal fisheries Deposit silt that maintains deltas Purify water Renew and nourish wetlands Provide habitats for aquatic life Conserve species diversity Ecological Services Performed by Rivers:

30. Dam: a barrier constructed to contain the flow of water or to keep out the sea

31. LEVEE - An embankment, continuous dike or ridge

32. What’s the Dam Problem? advantages & disadvantages Large losses of water through evaporation Large losses of water through evaporation Upstream, flooded land destroys forests or cropland and displaces people Upstream, flooded land destroys forests or cropland and displaces people Downstream flooding is reduced Downstream cropland and estuaries are deprived of nutrient-rich silt Downstream cropland and estuaries are deprived of nutrient-rich silt Reservoir is useful for recreation and fishing Can produce cheap, clean electricity (hydropower) Migration and spawning of some fish are disrupted Provides water for year-round irrigation of cropland

33. Case Study: China’s Three Gorges Dam (1) World’s largest hydroelectric dam and reservoir World’s largest hydroelectric dam and reservoir Reservoir will flood large areas. Reservoir will flood large areas. Destroyed many villages and displaced 1.2 mill people Destroyed many villages and displaced 1.2 mill people Submerged hundreds of mines and factories Submerged hundreds of mines and factories Benefits Benefits Electricity-producing potential is huge Electricity-producing potential is huge Holds back the Yangtze River floodwaters Holds back the Yangtze River floodwaters Allows cargo-carrying ships Allows cargo-carrying ships

34. Case Study: China’s Three Gorges Dam (2) Harmful effects Harmful effects Displaces about Displaces about million people million people Built over a seismic fault Built over a seismic fault Significance? Significance? Rotting plant and animal matter producing CH 4 Rotting plant and animal matter producing CH 4 Worse than CO 2 emissions Worse than CO 2 emissions Will the Yangtze River become a sewer? Will the Yangtze River become a sewer?

35. Egypt’s Aswan High Dam Provides electricity for ½ of Egypt. Crucial to supplying water during intense drought from 1984-1988. Rise in water table has increased soil salinization. Prevents flooding of Nile River. Resulted in decreased soil fertility of cropland Reduced nutrient flow to the Mediterranean has caused decreased primary productivity and harmed fishing industry

36. Transferring Water from One Place to Another  James Bay Canada - water diversion for electricity. Phase I - completed 8 power stations. Phase II & III – halted.  Opposition by Cree Indians to flooding of their ancestral hunting grounds (boreal forests and tundra)  New York state canceled contract to buy electricity and helped halt projects, scaled down to fewer projects. Flooding caused increased mercury levels in reservoirs  James Bay Canada - water diversion for electricity. Phase I - completed 8 power stations. Phase II & III – halted.  Opposition by Cree Indians to flooding of their ancestral hunting grounds (boreal forests and tundra)  New York state canceled contract to buy electricity and helped halt projects, scaled down to fewer projects. Flooding caused increased mercury levels in reservoirs

37. CANADA UNITED STATES NEWFOUNDLAND ATLANTIC OCEAN ONTARIO James Bay Hudson Bay Chisasibi QUEBEC New York City Chicago II I James Bay Watershed Project: Will alter flow of 19 major rivers to produce hydropower Constructing 600 dams and dikes. Displacing thousands of indigenous Cree and Inuit. Flooding boreal forest and tundra equal in size to Washington State.

38. Case Study: The Colorado River Basin— An Overtapped Resource (1) 2,300 km through 7 U.S. states 2,300 km through 7 U.S. states 14 Dams and reservoirs 14 Dams and reservoirs Located in a desert area within the rain shadow of the Rocky Mountains Located in a desert area within the rain shadow of the Rocky Mountains Water supplied mostly from snowmelt of the Rocky Mountains Water supplied mostly from snowmelt of the Rocky Mountains Supplies water and electricity for more than 25 million people Supplies water and electricity for more than 25 million people Irrigation of crops Irrigation of crops Recreation Recreation

39. Case Study: The Colorado River Basin— An Overtapped Resource (2) Four Major problems Four Major problems Colorado River basin has very dry lands Colorado River basin has very dry lands Modest flow of water for its size Modest flow of water for its size Legal pacts allocated more water for human use than it can supply Legal pacts allocated more water for human use than it can supply Amount of water flowing to the mouth of the river has dropped Amount of water flowing to the mouth of the river has dropped

40. Case Study: The Colorado River Basin— An Overtapped Resource (3) What will happen if some of the reservoirs empty out? What will happen if some of the reservoirs empty out? Economic and ecological catastrophe Economic and ecological catastrophe Political and legal battles over water Political and legal battles over water

41. The Colorado River Basin

42. Transferring Water from One Place to Another: Watershed transfer  Water transfer by tunnels, aqueducts, &/or underground pipes.  Illustrates (with dams) that you cannot do just one thing!  Water transfer by tunnels, aqueducts, &/or underground pipes.  Illustrates (with dams) that you cannot do just one thing!

43. Transferring Water from One Place to Another North Bay Aqueduct North Bay Aqueduct South Bay Aqueduct South Bay Aqueduct California Aqueduct CALIFORNIA NEVADA UTAH MEXICO Central Arizona Project Colorado River Aqueduct Los Angeles Aqueduct Shasta Lake Sacramento Fresno Phoenix Tucson ARIZONA Colorado River Sacramento River Sacramento River San Francisco Los Angeles San Diego  California Water Project Fig. 14-13 p. 323 Transfer of water from N. Cal. To S. Cal S. Cal. is more populated and grows a majority of the countries vegetables (as well as other crops like alfalfa)

44. Case Study: The Aral Sea Disaster (1) Large-scale water transfers in dry central Asia Large-scale water transfers in dry central Asia Salinity Salinity Wetland destruction and wildlife Wetland destruction and wildlife Fish extinctions and fishing Fish extinctions and fishing

45. Case Study: The Aral Sea Disaster (2) Wind-blown salt Wind-blown salt Water pollution Water pollution Climatic changes Climatic changes Restoration efforts Restoration efforts

46. Fig. 13-18a, p. 331 Stepped Art 19762006

47. Ship Stranded in Desert Formed by Shrinkage of the Aral Sea

48. Desalination:Desalination: Types:  Distillation - heating salt water to evaporate and condense the water, salt stays behind Types:  Distillation - heating salt water to evaporate and condense the water, salt stays behind  Reverse osmosis – Saltwater is pumped at high pressure through thin membrane whose pores filter out salts and allow freshwater to pass through Desalination is very expensive

49. 3 Major Causes of Water Waste 1.) Water subsidy policies - ex: dams, water transfer, irrigation. Creates low water prices that encourages waste Creates low water prices that encourages waste Help lower food prices Help lower food prices Stimulate local economies Stimulate local economies

50. Doctrine of Riparian rightsDoctrine of Riparian rights Anyone whose land has access to a flowing stream has the right to use it. Principle of prior appropriation 2.) Water Rights First user of a stream establishes legal right for continued use. Later users are cut off if a shortage occurs. Common law - ex: groundwater Subsurface water belongs to whoever owns the land Above it. Landowners w/draw whatever they need.

51. 3 Major Causes of Water Waste 3.) Fragmented Water Management Water saved in one area by planning and regulations can be offset by lack of such policies in another area. Water saved in one area by planning and regulations can be offset by lack of such policies in another area.

52. Using Water More Efficiently  Reduce losses due to leakage  Reform water laws  Improving manufacturing processes  Water efficient landscaping (xeriscaping)  Reuse “gray water” for watering lawns and nonedible plants.  Water efficient landscaping (xeriscaping)  Reuse “gray water” for watering lawns and nonedible plants.  Water efficient appliances

53. Improve irrigation efficiency 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% - 95%) Water usually pumped from underground and sprayed from mobile boom with sprinklers.

54. Reducing Agricultural Water Waste Use more efficient drip irrigation or trickle irrigation Choose climate specific crops that do not require irrigation for the area Develop crops for more drought tolerance Irrigate at night when evaporative loss is lower Use measures to reduce or slow runof. Ex: contour planting, strip cropping, terracing, etc. Monitor soil moisture levels to reduce unnecessary irrigation. Reduce meat consumption, because more water is used in animal production than in plant production.

55. 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 Reducing Water Waste in Industries, Homes, and businesses

56. Too Much Water: Floods  Natural phenomena Floodplain Levee Flood wall Dam Reservoir  Renew and replenish  Aggravated by human activities Fig. 14-22 p. 332

57. Solutions: Achieving a More Sustainable Water Future  Efficient irrigation  Water-saving technologies  Improving water management See Fig. 14-25 p. 336