1. RIVERS, GROUNDWATER, AND GLACIERS

2. Delta A fan-shaped deposit that forms when a river flows
into a quiet or large body
of water, such as a lake,
an ocean, or an inland sea.

3. Alluvial Fan A sloping triangle deposit of sediment
located where a mountain stream meets level land.

4. Tributary
A stream that runs
into another stream
or river.

5. Drainage Basins separated by
high elevations

7. Drainage Basin

9. Mississippi River Drainage Basin

12. Characteristics of Streams and Rivers
The ability of rivers to erode and transport sediment is affected by many characteristics that are interconnected.
Stream/river velocity
Stream/river gradient
Stream/river discharge
Channel shape

13. Stream Velocity

15. Formation of sand bars and cut-banks in
meandering rivers

16. Gradient or Slope

17. Discharge

19. Channel

20. Stream Erosion and Deposition

21. Stream Velocity

22. Turbulent flow-decreased velocity caused by objects in stream and shape of banks

25. Floodplain A wide, level area that borders a river and is covered by
its water during a
flood.

26. Unique Feature of Meandering Rivers: Oxbow Lakes:
are rivers that develop broad, looping
bends over time.
They shift there course across a valley
Floor over time causing it to widen
Unique Feature of Meandering Rivers:
Oxbow Lakes:
a crescent-shaped body of water formed
when sediments deposited by a river cuts off
a meander from the river.

33. Horseshoe Falls

35. Stages of River/Stream
Development

36. The Ideal Stream Cycle (W.M. Davis, 1880)
Not a Literal Time Sequence
Youth
Maturity
Old Age
Rejuvenation  

37. Youth V-Shaped Valley Fast Current Pot holes common Rapids Waterfalls
No Flood Plain
Drainage Divides Broad and Flat, Undissected by Erosion
Valley Being Deepened
Youth

38. Maturity (Early) V-Shaped Valley Beginnings of Flood Plain
Sand and Gravel Bars
Sharp Divides
Relief Reaches Maximum
Valleys stop deepening

39. Maturity (Late) Valley has flat bottom Narrow Flood Plain
Divides begin to round off
Relief diminishes
Sediment builds up, flood plain widens
River begins to meander
Maturity (Late)

40. Old Age Land worn to nearly flat surface (peneplain)
Resistant rocks remain as erosional remnants (monadnocks)
Shallow gradient
Slow current
Rivers meander across extremely wide, flood plains
Ox bow lakes
Levees
Deltas
Old Age

41. Rejuvenation Some change causes stream to speed up and cut deeper.
Uplift of Land
Lowering of Sea Level
Greater stream flow
Stream valley takes on youthful characteristics but retains features of older stages as well.
Can happen at any point in the cycle.

42. Rejuvenation of an old-age landscape

43. Rejuvenation of an early mature landscape

44. Arid and Humid Weathering Compared
Humid Climates
Arid Climates
Rainfall
Frequent
Rare, May Be Seasonal, Often Violent
Soil Cover
Thick
Thin or Absent
Vegetation
Sparse-no Continuous Cover
Chemical Weathering
Intense
Weak
Overall Landscape Evolution
Mostly Uniform Processes
Episodic Processes

45. Arid Erosion Cycle: Youth
V-shaped Valleys
Divides Flat, Undissected
Much Like Youth in Humid Climates
Arid Erosion Cycle: Youth

46. Arid Erosion Cycle: Maturity
Slopes Stay Steep, Retreat
Alluvial Fans
Playa Lakes
Pediments
Arid Erosion Cycle: Maturity

47. Arid Erosion Cycle: Old Age
Inselbergs
Playa Lakes
Pediplain
Arid Erosion Cycle: Old Age

48. River meanders across floodplain
Base level drops,
or region uplifts.
Terrace forms in floodplain
Further incision cuts a new terrace

49. A flight of river terraces

50. River and Glacial Valleys
U-shaped
V-shaped

51. River and Glacial Valleys

52. Groundwater

53. Groundwater is water that completely saturates (fills) the pore spaces of soil or rock formation below the water table. Water that shares pore space with air is called soil moisture.

54. Groundwater is the largest resevoir of fresh water that is readily available to humans

57. Four factors that influence the rate at which water enters the groundwater “system”
1. Type of rock or soil
2. Climate (in dry areas, a lot of water evaporates before it soaks into the ground.)
3. Topography (steep slopes = runoff)
4. Vegetation (more vegetation = more water stays where it lands)

58. Porosity
Porosity is percentage of total volume of rock or sediment that consists of pore spaces.

59. Factors that affect porosity
Particle shape (round sediments have more pore spaces than angular sediments)
Sorting (poorly sorted sediments have fewer spaces than well-sorted sediments, because smaller pieces fill the spaces between bigger ones)

60. Permeability
Permeability is the ability of water to flow through a rock or sediment layer, and the rate at which it does so.

62. Factors that affect permeability
Pore Size- larger the pore space are, the easier water passes through. Clay and silt-sized sediments can be impermeable, because their shape allows them to overlap one another like stacks of paper.
Interconnection of Pores- Pumice is not permeable because, although it is very porous, its holes are not interconnected.
Presence of cracks in rock layers

63. Water Table
zone of aeration
zone of saturation

65. What Factors affect the Water table?
Amount of Rainfall-more rain = higher water table
Amount of time between rains
Season
Slope
Soil thickness
Climate
How much water is being removed

67. Aquifer
An Aquifer is an underground layer of water-bearing, permeable rock, or unconsolidated sediment, from
which groundwater can be easily extracted.

68. Confined Aquifer
Gravitational
pressure

69. Perched Aquifers (unconfined)

70. Karst Aquifer
Loudoun County, VA

71. Geyser

73. Artesian Well Artesian formation:
An arrangement of permeable layer of rock sandwiched between two layers of impermeable rock.

74. Groundwater Contamination

75. Saltwater Intrusion

76. Karst Topography
Karst is a topography in which the landscape is largely shaped by the dissolving action of acidic water on carbonate bedrock (usually limestone, dolomite, or marble).
This geological process, occurring over many thousands of years, results in unusual surface and subsurface features ranging from sinkholes, vertical shafts, disappearing and emerging streams, and springs, to complex underground drainage systems and caves.
Karst provides water for many Virginians.

78. Vertical Shafts

80. Underground Rivers

85. Caves

86. Sinkholes

87. Karst Counties in Virginia

88. West- Virginia Karst
eeer

89. Glaciers

90. Glacier: a Flowing Stream of Ice
There are two types of glaciers:
Mountain
Continental (Greenland, Antarctica)

91. Mountain Glacier Landforms

92. Continental Glacier Landforms

93. Snowfall vs Melting & Evaporation (Ablation)
Zone of Accumulation
Snowfall Exceeds Melting & Evaporation
Excess Snow Turns to Ice & Flows Out
Zone of Melting or Ablation
Melting & Evaporation Exceeds Snowfall
Melting Excess Made up by Ice Flowing in
Terminus of Glacier
Snowfall & Inflow = Melting & Evaporation (Ablation)

94. Anatomy of a Glacier

95. A Typical Glacial Advance and Retreat

96. As long as Accumulation = Ablation, the Glacier Front Remains Fixed

97. If Accumulation Exceeds Ablation, the Glacier Advances

98. If Ablation Exceeds Accumulation, the Glacier Retreats

99. Eventually, Material Trapped in the Ice Reaches the Terminus

100. Results of Glaciation Abrasion Polish Striations Chatter Marks
Crescentic Gouges
Bedrock Scour
Deposition
Till
Outwash
Varved Clays
Meltwater Erosion

101. Glacial Deposits

102. River and Glacial Valleys