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Chapter 14

Water Resources. Chapter 14. Why is water so important?. All organisms are made up mostly of water Plays a key role in; -sculpting the earth’s surface -moderating climate -diluting pollution. I. WATER’S UNIQUE PROPERTIES. High Heat of Evaporation Great Dissolving Power

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Chapter 14

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  1. Water Resources Chapter 14
  2. Why is water so important? All organisms are made up mostly of water Plays a key role in; -sculpting the earth’s surface -moderating climate -diluting pollution
  3. I. WATER’S UNIQUE PROPERTIES High Heat of Evaporation Great Dissolving Power Adhesion, Cohesion and Capillarity Expands when frozen Hydrogen Bonding Liquid over a large temperature range Changes Temperature Slowly Maintains pH
  4. II. THE WATER CYCLE Also called the HYDROLOGICAL CYCLE Process by which water alternates form due to evaporation and condensation. A. Water into the atmosphere B. Water out of the atmosphere C. Water over and through the soil
  5. A. Water Into The Atmosphere Water enter the atmosphere by two processes…. 1. Evaporation 2. Transpiration The amount of water that the atmosphere can hold depends on the temperature. High temperature = increased moisture Low temperature = decreased moisture
  6. Factors that influence Evaporation RELATIVE HUMIDITY: the amount of water vapor in the air compared to the maximum that it can hold at a particular temperature. Increased humidity = decreases evaporation Decreased humidity = increased evaporation
  7. B. Water Out Of The Atmosphere Precipitation: All forms of moisture out of the atmosphere Rain falls unevenly across the earth’s surface. Some areas receive practically no precipitation and other areas receive heavy rain on a daily basis. Three principal factors control global water deficits and surpluses: Global atmospheric circulation Proximity to water sources Topography
  8. Rain Shadow
  9. The Rain Shadow’s Effect on Precipitation Rain Shadow Effect: Air sweeps up the windward side of a mountain, pressure decreases, and the air cools. Moisture in the air condenses. Rain falls on the mountaintops Cool, dry air descends creating dry areas with very little precipitation.
  10. C. Water Over And Through The Soil 1. Runoff or Surface Water: -Water that flows directly over the surface into streams that form rivers which make lakes and eventually run into the oceans. Watershed or Drainage Basin: -The land area that drains a particular waterway Example: Ohio River Watershed is where we live
  11. Water that doesn’t runoff, is absorbed by the soil or evaporates. Infiltration is the process of water seeping through the various layers of soil. Infiltration:
  12. Where is Groundwater Stored? Aquifers Porous layers of sand, gravel, or rock lying below the water table Artesian Aquifer Pressurized aquifer where water flows without pumping. (Examples: seeps and springs) Recharge zones: Areas where water infiltrates into an aquifer Recharge rate is often very slow.
  13. Groundwater in Aquifers
  14. Flowing artesian well Precipitation Evaporation and transpiration Well requiring a pump Evaporation Confined Recharge Area Runoff Aquifer Stream Infiltration Water table Lake Infiltration Unconfined aquifer Confined aquifer Less permeable material such as clay Confirming permeable rock layer Ground Water
  15. III. SUPPLY OF WATER RESOURCES -97% of water is found in the oceans -3% freshwater - most locked up in glaciers or too deep to obtain. -0.014% is available for use
  16. Freshwater Readily accessible freshwater Groundwater 0.592% Biota 0.0001% Lakes 0.0007% Rivers 0.0001% 0.014% Ice caps and glaciers 0.592% Soil moisture 0.0005% Atmospheric water vapor 0.0001% FRESHWATER RESOURCES Fig. 13.2, p. 296
  17. Major Water Compartments Water may reside briefly in one compartment or stay there for eons. The length of time water typically spends in a compartment is called the Residence Time. Average residence time of water in the ocean: 3,000 yearsbefore entering the water cycle.
  18. The Oceans as a Major Water Compartment 97% of all liquid water on the earth. 90% of the earth’s biomass Ocean currents moderate the climate by redistributing warm and cold water around the earth like a global ocean conveyor belt.
  19. Global Ocean Conveyor System
  20. Frozen Water Compartments Glaciers, Ice, and Snow 2.4% of world’s water is classified as fresh. 90% in glaciers, ice caps, and snowfields Now, Antarctic glaciers contain nearly 85% of all ice in the world. Greenland, together with ice floating around the North Pole, is another 10%.
  21. Ground Water Compartments Ground water is the second largest reservoir of fresh water
  22. River & Streams Water Compartments Rivers and Streams Precipitation that does not evaporate or infiltrate Discharge: The amount of water that passes a fixed point in a given amount of time Usually expressed as cubic feet per second
  23. Major Rivers of the World
  24. Lakes and Ponds Water Compartments Lakes and Ponds Ponds: Bodies of water shallow enough for rooted plants to grow over most of the bottom. Lakes: Inland depressions that hold standing fresh water year-round.
  25. Wetlands are Water Compartments Wetlands Play a vital role in hydrologic cycle Lush plant growth stabilizes soil and retards surface runoff, allowing more aquifer infiltration. Disturbance reduces natural water-absorbing capacity, resulting in floods and erosion in wet periods, and less water flow the rest of the year. Half of U.S. wetlands are gone.
  26. The Atmosphere: A Small Water Compartment The Atmosphere: Among the smallest water reservoirs < 0.001% of total water supply Has the most rapid turnover rate Mechanism for distributing fresh water over landmasses and replenishing terrestrial reservoirs
  27. IV. Use of Water Resources in the United States EASTERN USA: The largest uses of water are for energy production, cooling, and manufacturing. WESTERN USA: the major use is for agriculture Most serious problems: flooding, urban shortages, pollution.
  28. United States Agriculture 38% Power cooling 38% Industry 11% Public 10%
  29. Water Withdrawal and Consumption
  30. Typical Household Water Use in U.S.
  31. Average Annual Precipitation
  32. Acute shortage Adequate supply Shortage Metropolitan regions with population greater than 1 million
  33. Personal Water Usage
  34. V. Too Little Water According to the experts there are four causes of water scarcity… 1. Dry climate 2. Desiccation 3. Drought 4. Water stress
  35. WORLD WATER STRESS Europe North America Africa Asia South America Australia Stress High None
  36. VI. INCREASING FRESHWATER SUPPLIES There are six ways to increase the supply of freshwater in a particular area: A. Dams/Reservoirs B. Transferring Surface Water C. Withdrawing Groundwater D. Desalination E. Cloud Seeding F. Decreasing Water Waste
  37. Dams/Reservoirs -Capture and store runoff that can be released as needed. -Worldwide they have increased available runoff by 1/3. Pros -Increase water for irrigation and recreation -Hydroelectric power Cons -Decrease water flow -Destroy ecosystems -increase evaporation
  38. Downstream cropland and estuaries are deprived of nutrient-rich silt Flooded land destroys forests or cropland and displaces people Large losses of water through evaporation Downstream flooding is reduced Reservoir is useful for recreation and fishing Provides water for year-round irrigation of cropland Can produce cheap electricity (hydropower) Migration and spawning of some fish are disrupted Using Dams and Reservoirs to Supply More Water
  39. China’s 3 Gorges Dam
  40. Transferring Surface Water - Often associated with dams and reservoirs -Moving water from rich to depleted areas - California Water Project -Aral Sea
  41. http://ag.arizona.edu/AZWATER/arroyo/101comm.html CALIFORNIA NEVADA Shasta Lake UTAH Oroville Dam and Reservoir Sacramento River Feather River Lake Tahoe North Bay Aqueduct Sacramento San Francisco Hoover Dam and Reservoir (Lake Mead) Fresno South Bay Aqueduct Colorado River Los Angeles Aqueduct San Luis Dam and Reservoir ARIZONA California Aqueduct Central Arizona Project Santa Barbara Colorado River Aqueduct Los Angeles Phoenix Salton Sea San Diego Tucson MEXICO
  42. C. Withdrawing Groundwater -Removal of water from AQUIFERS -In U.S.; 50% of drinking water and 43% of irrigation water come from the ground. Cons -Decrease water table -Deplete aquifers -Draw chemicals/salt water -Aquifer subsidence -Cone of Depression Pros -Available all year -Less evaporation
  43. Major irrigation well Well contaminated with saltwater Water table Sea Level Salt water Fresh groundwater aquifer Interface Interface Saltwater Intrusion Normal Interface
  44. The Ogallala Aquifer
  45. D. Desalination: -Removal of salts from ocean or brackish water -Two methods: Reverse Osmosis Distillation
  46. Reverse Osmosis
  47. E. Cloud Seeding -Creating rain by dumping chemicals into the atmosphere Drawbacks: -Can’t be used in extremely arid regions -Introduce large amounts of chemicals into the soil/water
  48. 1. Commercially: F.Decreasing Water Waste A. Improving manufacturing processes B. Improving irrigation techniques
  49. 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. 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.
  50. A. Reduce losses due to leakage 2. Home, Businesses B. Reform water laws C. Water efficient landscaping (XERISCAPING) D. Water efficient appliances
  51. VII. Too Much Water - Floods -Natural phenomena with spillage intoFLOOD PLANS -Renew and replenish -Aggravated by human activities
  52. Why Do We Build in the Flood Plains? Over $1 trillion in real estate in USA flood plains -Fertile soil -Ample Water -Transportation -Flat
  53. Reservoir Dam Levee Flood wall Floodplain
  54. A. FLOOD CONTROL PRACTICES 1. CHANNELIZATION: Deepen, widen, and straighten waterways
  55. 2. ARTIFICIAL LEEVES: Walls to prevent water into floodplains 3. FLOOD CONTROL DAMS
  56. Levee Failures During Katrina
  57. B. FLOOD PLAIN MANAGEMENT Best practice for managing floods Determine flood frequency based on years of data Prohibit certain activities and buildings Construct a floodway
  58. Extremely severe Very severe Moderately severe FLOOD PRONE AREAS Somewhat severe Not severe
  59. VIII. Water Rights in the USA A. SURFACE WATER EAST: Doctrine of Riparian Rights -Anyone whose land adjoins a stream has the right to use H2O as long as some remains WEST: Principle of Prior Appropriation -1st come, 1st served -Later users are cutoff to satisfy early users
  60. B. GROUND WATER – COMMON LAW Ground water belongs to whoever owns the land above Owners can withdraw as much as they want Can sell, trade or lease to make money
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