1. Earth Science, 13e
Tarbuck & Lutgens

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

3. Chapter 5 Opener

4. 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

5. The hydrologic cycle

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

7. Drainage basins and divides

8. 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)
Discharge = Depth x Width x Velocity

9. Running water Upstream-downstream changes Profile
Cross-sectional view of a stream
From headwaters (source) to mouth
Profile is a smooth curve
Gradient decreases from the headwaters to the mouth
Factors that increase downstream
Velocity
Discharge
Channel Size

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

11. Longitudinal profile of a stream

12. FIGURE 5.11

13. Running water The work of streams Erosion Transportation
Transported material is called the stream’s load
Dissolved Load – minerals (oxygen, salts, nitrogen carbon dioxide)
Discussed in ppm (parts per million)
Velocity has little to no effect on
Suspended Load - silt/clay
Usually the largest load of a stream
Settling velocity
Bed Load –move material via saltation
Discuss the location and movement of this material

14. Running water The work of streams Transportation
Load is related to a stream’s
Competence – maximum particle size
Capacity – maximum load
Capacity and Competence are related to discharge
Greater the discharge the greater the capacity competence
Gradient
Examples – Low  Mississippi Delta High  Colorado River going through the grand canyon (drops 10ft/mi)
Stream capacity is a measure of the total sediment (material other than water) a stream can carry
Competence is a measure of the streams ability to move sediment

15. 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

16. 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

17. Running water 5.6 Base level Two general types
Point at which a stream deposits into a larger body of water that is usually lentic or lotic.
Lentic  standing water
Lotic  Running water
Estuaries are the more common end point.
Two general types
Ultimate – sea level
Erosion and transport processes becomes weaker and depositional process takes over.
Temporary – Local
Includes lakes, resistant layers of rock, and point at which tributaries enter a larger stream
What happens to the velocity of a stream as it enters a lake?
Changing causes readjustment of the stream – depositional or erosional processes will change.

18. Adjustment of base level to changing conditions

19. Running water Stream valleys Types of Stream Valleys
Narrow, Steep, Wide
Consists of the channel and the surrounding terrain of that contributes water to the stream.
Most stream valleys are wider at the top than the bottom.
Is the stream the only agent working on the stream valley?
Valley sides are shaped by
Weathering
Work of wind and water on the surface
Overland flow
Runoff
Mass wasting
Large and sudden movements of land mass

20. Running water Characteristics of narrow valleys V-shaped
Created by the hydraulic powers if the stream moving bed load across the bed of the channel in turbulent water.
Down cutting toward base level is the dominant activity
Features often include:
Rapids –result of resistant rock acting as a temporary base level
Down cutting continues downstream
Waterfalls – Places where the stream makes an abrupt drop
Both are a result of a variation in erodability of the bedrock
Highest water fall in the world is Angel Falls

21. V-shaped valley of the Yellowstone River

22. Running Water Characteristics of wide valleys
Stream is near base level
Downward erosion is less dominant
Stream energy is directed from side to side
Floodplains
Over time floodplains will widen
Mississippi River has areas w/ 100mi between divides
Features often include
Meanders
Incised Meanders – Found in steep narrow valleys
Created by a shifting in base level.
Cutoffs  plays a major part in the shifting of deltas
Oxbow lakes

23. Continued erosion and deposition widens the valley

24. Characteristics of a wide stream valley

25. A meander loop on the Colorado River

26. 5.8 Depositional Landforms
Streams can create depositional features through out the course of the stream.
Small-scale/short-term features
Deposits are referred to as bars
Often consist of both medium and fine grained material.
Temporary feature of the stream channel
Relocated as streams transport material toward the ocean.
Large-scale/long-term features
Deltas, natural levees and alluvial fans
All of the features are found most often where flow velocity has ______.
decreased

27. Depositional Landforms
Deltas
Formed where streams enter a lentic body of water
Ex. Lakes, in-land sea, or ocean
Depositional processes take over at this point and start to convert the main stream into distributaries
Distributaries take water away from the main stream.
Natural Levees
Form where streams have overflowed their banks
Once the stream leaves it’s channel the velocity decreases quickly resulting in the deposition of sediment.
Over time the consistent flooding may result in the large levees
Levees of the Mississippi can reach up to 20ft (6m)
Areas behind levees tend to drain poorly and are often result in Yazoo tributaries and back swamps
Alluvial Fans
Result of streams w/ high flow velocity entering a broad flat plain

28. Formation of natural levees by repeated flooding

29. Running water 5.9 Drainage patterns
Networks of streams that form distinctive patterns
Types of drainage patterns
Dendritic- the most common type of drainage pattern
Schuylkill river and Delaware
Characterized by its tree-like branching
Underlying geology is generally uniform and resistant to erosional processes
Radial – spokes on a wheel
Affiliated w/ volcanoes
Rectangular- forms as a result of crisscrossing of joints and/or faulting
Characterized by 90degree angles
Trellis - rectangular pattern in which tributaries are parallel to each other

30. Drainage patterns

31. Running water Floods and flood control
Floods are the most common geologic hazard
Causes of floods
Weather
Human interference with the stream system
Flood Videos
NASA Mississippi Flooding
Mississippi Flooding June 2012

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

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

34. Same satellite view during flooding in 1993

35. 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

36. 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

37. 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

38. Features associated with subsurface water

39. 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

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. Old Faithful geyser in Yellowstone National Park

42. 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

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

44. Artesian systems

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

46. 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

47. 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)

48. Cave features in Carlsbad Caverns National Park

49. 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

50. Features of karst topography

51. End of Chapter 5