1. Earth Science, 13e
Tarbuck & Lutgens

2. Running Water and Groundwater Earth Science, 13e Chapter 5
Stanley C. Hatfield
Southwestern Illinois College

3. Earth as a system: the hydrologic cycle
Illustrates the circulation of Earth’s water supply
Processes involved in the cycle
Precipitation
Evaporation
Infiltration
Runoff
Transpiration

4. The hydrologic cycle

5. Running water Drainage basin
Land area that contributes water to a river system
A divide separates drainage basins

6. Drainage basins and divides

7. 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)

8. 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
Discharge

9. Running water Upstream-downstream changes Profile
Factors that increase downstream
Channel size
Factors that decrease downstream
Gradient, or slope
Channel roughness

10. Longitudinal profile of a stream

11. Running water The work of streams Erosion Transportation
Transported material is called the stream’s load
Dissolved load
Suspended load
Bed load

12. 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

13. 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

14. 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

15. Formation of natural levees by repeated flooding

16. 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

17. Adjustment of base level to changing conditions

18. Running water Stream valleys Valley sides are shaped by
Weathering
Overland flow
Mass wasting
Characteristics of narrow valleys
V-shaped
Downcutting toward base level

19. 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

20. V-shaped valley of the Yellowstone River

21. Continued erosion and deposition widens the valley

22. Characteristics of a wide stream valley

23. Running water Stream valleys Characteristics of wide valleys
Floodplain
Features often include
Meanders
Cutoffs
Oxbow lakes

24. A meander loop on the Colorado River

25. Running water Drainage patterns
Networks of streams that from distinctive patterns
Types of drainage patterns
Dendritic
Radial
Rectangular
Trellis

26. Drainage patterns

27. Running water Floods and flood control
Floods are the most common geologic hazard
Causes of floods
Weather
Human interference with the stream system

28. Running water Floods and flood control Engineering efforts
Artificial levees
Flood-control dams
Channelization
Nonstructural approach through sound floodplain management

29. Satellite view of the Missouri River flowing into the Mississippi River near St. Louis

30. Same satellite view during flooding in 1993

31. 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

32. 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

33. 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

34. Features associated with subsurface water

35. 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

36. 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

37. Old Faithful geyser in Yellowstone National Park

38. 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

39. Formation of a cone of depression in the water table

40. Artesian systems

41. Water beneath the surface (groundwater)
Environmental problems associated with groundwater
Treating it as a nonrenewable resource
Land subsidence caused by its withdrawal
Contamination

42. 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

43. 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)

44. Cave features in Carlsbad Caverns National Park

45. 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

46. Features of karst topography

47. End of Chapter 5