1. © 2012 Pearson Education, Inc. Earth Science, 13e Tarbuck & Lutgens

2. © 2012 Pearson Education, Inc. Running Water and Groundwater Earth Science, 13e Chapter 5 Stanley C. Hatfield Southwestern Illinois College

3. © 2012 Pearson Education, Inc. Earth as a system: the hydrologic cycle  Illustrates the circulation of Earth’s water supply  Total of 1.36 billion km 3  97.2% is stored in global oceans  Processes involved in the cycle Precipitation Evaporation Infiltration Runoff Transpiration

4. © 2012 Pearson Education, Inc.

5. The hydrologic cycle

6. © 2012 Pearson Education, Inc. Running water  Drainage basin Land area that contributes water to a river system A divide separates drainage basins

7. © 2012 Pearson Education, Inc. Drainage basins and divides

8. © 2012 Pearson Education, Inc. Running water  Streamflow Factors that determine velocity Gradient, or slope Channel characteristics Shape Size Roughness Discharge – volume of water flowing in the stream (generally expresses as cubic feet per second)

9. © 2012 Pearson Education, Inc. Running water  Upstream-downstream changes Profile Cross-sectional view of a stream From head (source) to mouth Profile is a smooth curve Gradient decreases from the head to the mouth Factors that increase downstream Velocity Discharge

10. © 2012 Pearson Education, Inc. Running water  Upstream-downstream changes Profile Factors that increase downstream Channel size Factors that decrease downstream Gradient, or slope Channel roughness

11. © 2012 Pearson Education, Inc. Longitudinal profile of a stream

12. © 2012 Pearson Education, Inc. Running water  The work of streams Erosion Transportation Transported material is called the stream’s load Dissolved load Suspended load Bed load

13. © 2012 Pearson Education, Inc. Running water  The work of streams Transportation Load is related to a stream’s Competence – maximum particle size Capacity – maximum load Capacity is related to discharge

14. © 2012 Pearson Education, Inc. Running water  The work of streams Transportation Deposition Caused by a decrease in velocity Competence is reduced Sediment begins to drop out Stream sediments Known as alluvium Well-sorted deposits

15. © 2012 Pearson Education, Inc. Running water  The work of streams Transportation Features produced by deposition Deltas – exist in ocean or lakes Natural levees – form parallel to the stream channel Area behind the levees may contain back swamps or yazoo tributaries

16. © 2012 Pearson Education, Inc. Formation of natural levees by repeated flooding

17. © 2012 Pearson Education, Inc. Running water  Base level Lowest point a stream can erode to Two general types Ultimate – sea level Temporary, or local Changing causes readjustment of the stream – deposition or erosion

18. © 2012 Pearson Education, Inc. Adjustment of base level to changing conditions

19. © 2012 Pearson Education, Inc. Running water  Stream valleys Valley sides are shaped by Weathering Overland flow Mass wasting Characteristics of narrow valleys V-shaped Downcutting toward base level

20. © 2012 Pearson Education, Inc. Running water  Stream valleys Characteristics of narrow valleys Features often include Rapids Waterfalls Characteristics of wide valleys Stream is near base level Downward erosion is less dominant Stream energy is directed from side to side

21. © 2012 Pearson Education, Inc. V-shaped valley of the Yellowstone River

22. © 2012 Pearson Education, Inc. Continued erosion and deposition widens the valley

23. © 2012 Pearson Education, Inc. Characteristics of a wide stream valley

24. © 2012 Pearson Education, Inc. Running water  Stream valleys Characteristics of wide valleys Floodplain Features often include Meanders Cutoffs Oxbow lakes

25. © 2012 Pearson Education, Inc. A meander loop on the Colorado River

26. © 2012 Pearson Education, Inc. Running water  Drainage patterns Networks of streams that from distinctive patterns Types of drainage patterns Dendritic Radial Rectangular Trellis

27. © 2012 Pearson Education, Inc. Drainage patterns

28. © 2012 Pearson Education, Inc. Running water  Floods and flood control Floods are the most common geologic hazard Causes of floods Weather Human interference with the stream system

29. © 2012 Pearson Education, Inc. Running water  Floods and flood control Engineering efforts Artificial levees Flood-control dams Channelization Nonstructural approach through sound floodplain management

30. © 2012 Pearson Education, Inc. Satellite view of the Missouri River flowing into the Mississippi River near St. Louis

31. © 2012 Pearson Education, Inc. Same satellite view during flooding in 1993

32. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  Largest freshwater reservoir for humans  Geological roles As an erosional agent, dissolving by groundwater produces Sinkholes Caverns An equalizer of stream flow

33. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  Distribution and movement of groundwater Distribution of groundwater Belt of soil moisture Zone of aeration Unsaturated zone Pore spaces in the material are filled mainly with air

34. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  Distribution and movement of groundwater Distribution of groundwater Zone of saturation All pore spaces in the material are filled with water Water within the pores is groundwater Water table – the upper limit of the zone of saturation

35. © 2012 Pearson Education, Inc. Features associated with subsurface water

36. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  Distribution and movement of groundwater Distribution of groundwater Porosity Percentage of pore spaces Determines storage of groundwater Permeability Ability to transmit water through connected pore spaces Aquitard – an impermeable layer of material Aquifer – a permeable layer of material

37. © 2012 Pearson Education, Inc.

40. Water beneath the surface (groundwater)  Features associated with groundwater Springs Hot springs Water is 6–9° C (10–15° F) warmer than the mean air temperature of the locality Heated by cooling of igneous rock Geysers Intermittent hot springs Water turns to steam and erupts

41. © 2012 Pearson Education, Inc. Hot Springs

42. © 2012 Pearson Education, Inc. Hot Springs

43. © 2012 Pearson Education, Inc. Geysers Intermittent hot springs Water turns to steam and erupts.  Associated with plate edges and volcanic activity

44. © 2012 Pearson Education, Inc. Geyser Formation Cycle

45. © 2012 Pearson Education, Inc. Old Faithful geyser in Yellowstone National Park

46. © 2012 Pearson Education, Inc. Geyser in New Zealand

47. © 2012 Pearson Education, Inc. Geyser in New Zealand

48. © 2012 Pearson Education, Inc. Geyser in New Zealand

49. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  Features associated with groundwater Wells Pumping can cause a drawdown (lowering) of the water table Pumping can form a cone of depression in the water table Artesian wells Water in the well rises higher than the initial groundwater level

50. © 2012 Pearson Education, Inc. Formation of a cone of depression in the water table

51. © 2012 Pearson Education, Inc. Artesian systems

52. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  Environmental problems associated with groundwater Treating it as a nonrenewable resource Land subsidence caused by its withdrawal Contamination

53. © 2012 Pearson Education, Inc. Environmental Problems Associated with Groundwater  Overuse and contamination threatens groundwater supplies in some areas. Irrigation from wells Land subsidence caused by its withdrawal The land actually sinks when water is taken out of the ground Compacts to fill up the empty space San Joaquin Valley of California Water was pumped for irrigation for 50 years

54. © 2012 Pearson Education, Inc.

55. Environmental Problems Associated with Groundwater Contamination  Passing water through the soil usually eliminates pollutants  Different kinds of soil filter out bacteria, inorganic chemicals and oil by- products

56. © 2012 Pearson Education, Inc. Environmental Problems Associated with Groundwater

57. © 2012 Pearson Education, Inc. Environmental Problems Associated with Groundwater  Sewage is usually filtered easily in the organic and subsoil layers  Organic chemicals like pesticides, fertilizers or road salt need more dense soils  Oil residues may pass through a great deal of soil before being absorbed

58. © 2012 Pearson Education, Inc. Environmental Problems Associated with Groundwater  areas where dumping of materials has been practiced may have contaminated ground water

59. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  Geologic work of groundwater Groundwater is often mildly acidic Contains weak carbonic acid Dissolves calcite in limestone Caverns Formed by dissolving rock beneath Earth’s surface Formed in the zone of saturation

60. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  a naturally formed underground chamber.  Erosion forms most caverns at or below the water table in the zone of saturation.  Travertine is a form of limestone that is deposited by hot springs or as a cave deposit.

61. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  Geologic work of groundwater Caverns Features found within caverns Form in the zone of aeration Composed of dripstone Calcite deposited as dripping water evaporates Common features include stalactites (hanging from the ceiling) and stalagmites (growing upward from the floor)

62. © 2012 Pearson Education, Inc. Cave features in Carlsbad Caverns National Park

63. © 2012 Pearson Education, Inc. Water beneath the surface (groundwater)  Geologic work of groundwater Karst topography Formed by dissolving rock at, or near, Earth’s surface Common features Sinkholes – surface depressions Sinkholes form by dissolving bedrock and cavern collapse Caves and caverns Area lacks good surface drainage

64. © 2012 Pearson Education, Inc. Features of karst topography

65. © 2012 Pearson Education, Inc. Sinkhole

66. © 2012 Pearson Education, Inc. End of Chapter 5