2. Chapter 6 Running Water and Groundwater

3. Who cares about running water or groundwater?

4. Water Cycle What is it? How is it powered (what makes it happen)?
Circulation of Earth’s water supply
How is it powered (what makes it happen)?
Sun and gravity
What are the three main steps?
Evaporation, Precipitation, Runoff
Water Cycle

6. Water Cycle How can the water return to the ocean?
From runoff and rivers
From precipitation
From ground water

7. Water Cycle Balance How can the water cycle be balanced?
Have equal amounts of….
Water evaporating or transpiring (water going up)
Water that precipitates (water coming down)

8. Groundwater How does water get into the ground?
Infiltration- movement of surface water into rock and soil through cracks and pores (permeable)
What happens to it from there?
Flows through the ground into streams, lakes, aquifers, or the ocean
What could make infiltration slow down?
Cold, type of soil, type of rocks
Groundwater

9. StreamFlow Streams carry water down hill from land to the ocean
When it is straight, the fastest water is in the center
Why?
Least friction
If it curves, the fastest section moves more toward the outer bank
How much sediment it can carry or erode depends on how fast it is going
StreamFlow

11. Streamflow Stream Channel- Gradient –
The path the stream follows
Gradient –
The slope of the channel
If it has a high slope what can you assume?

12. Streamflow Discharge –
How much water (volume) is flowing past a certain point at a given time
Why would this be important?

13. Stream Profile
If you were to take a side view of a stream from beginning (source) to end (mouth)
Shows the elevation change (gradient)
When gradient decreases (the slope is getting flatter) what happens to the sediment?
Increases because it is getting slower and sediments start to settle instead of being carried

17. Tributaries What are they? A stream that empties into another stream
creek-> stream -> river -> bay

19. Base Level

21. Meanders What is meandering?
When a stream gets to flatter land it usually has a lot of bends and turns in its channel

22. Meander

23. What do streams do? Erosion
Picks up sediment and moves it based on the sediment size and speed of the water
Abrasion
Running small sand and other particles over the stream bed and banks like sandpaper

24. Sediment is moved in 3 ways
Dissolved Load
In a solution, usually represented in parts per million or ppm
Average is around 120 ppm
Suspended Load
Sediment like sand silt and clay stay the same just picked up and flow with the water
Brown water
Most sediment is carried this way.

25. Sediment is moved in 3 ways
Bed Load
Sediment too large to be picked up so it just rolls along the bottom

26. Competence vs Capacity
How big of an item the stream can carry
Capacity
How much in total it can carry

27. Deposition Cutbank – Point Bar –
outside edge of a stream that gets eroded
Point Bar –
Inside edge of the stream where sediment is deposited

29. Deposition
Delta
Sediment that gathers at the mouth of a stream where it empties into a lake or ocean.
Grows over time

32. Deposition
Natural Levee

33. Stream Valleys Narrow Valley More V Shaped
Stream is digging down more than it is out
Usually have rapids, waterfalls

34. Stream Valleys Wide Valley Stream is eroding out more than down
Usually happens when the slope is low
Widens the valley
Creates floodplains
Meanders more

35. Oxbow Lake
Where a stream that is meandering cuts off a section by finding a faster route

38. Floods When the discharge is more than the capacity Most are caused by
More water than the stream can handle and it overflows
Most are caused by
Rapid rain
Snow melting
What’s the difference between a flash flood and regional flood?

39. Flood Control Artificial Levees
Man-made piles of sand/silt to help make the banks higher
Most are made to simply control the water flow, but not for very heavy flooding

41. Flood Control Flood Control Dam
Store flood water and let it out slowly
Just about one on every major river now
Plus: they help control the water in a manner we can handle
Minus: they build up sediment that reduces its effectiveness

45. Water Underground

46. Groundwater How does it get into the ground?
Infiltration
What allows it to move underground?
Porosity: The percentage of the total rock or sediment that contains pores

47. Porosity

48. Groundwater Permeability- Impermeable?
The ability for fluid to move through a material
Impermeable?
Fluid cannot move through it
Groundwater moves through the interconnected pores and openings
If the pores are big
It can flow faster
If the pores are small
It acts like a funnel and moves slower

49. Aquifer Aquifer- Aquitard-
Permeable rock or sediment layers that contain water
Important source for wells to get water
Aquitard-
Impermeable layers that prevent water flow

50. Aquifer

51. Water Table Zone of Saturation Zone of Aeration Water Table
The area where all the pore spaces are filled by water
Typically slightly above the local river or ocean level (flows down hill)
Zone of Aeration
The area where not all the pore spaces are filled
Typically above the saturation line
Water Table
Upper limit of the zone of saturation

52. Water Table

54. Springs
What is it?
Where the water table meets the ground level and water comes out
Form when aquitards are horizontal and block the water from moving down
Spring water?

55. Spring Water?
Aquafina
The source water is municipal tap water which is then processed using reverse osmosis, charcoal filtration, ozonation and several other filtration steps which the company calls their HYDRO-7 (tm) filtration system.
Fiji Water
The origin of FIJI Natural Artesian Water is rainfall, which filters through volcanic stone over hundreds of years on the main island of Viti Levu in Fiji.

56. Springs

57. Springs Hot Spring Geyser
6-9 Celsius warmer than the air temperature around it
Nearly 1000 in the US, mostly in the west
Heated from being underground
Geyser
Water is trapped underground and heated
Occasionally it will shoot up due to a build up of force to relieve pressure
Form over hot igneous rocks and magma chambers

58. Japanese Snow Monkeys

59. Old Faithful Geyser

60. Well
A hole dug down to the zone of saturation to draw water to the surface.
Mostly used for irrigation for crops
Industries and home come second and third
Which is better?
Dig a well above the water table?
Dig a well to the water table?
Dig a well below the water table?
Dig it well below the water table to ensure you can still get water in times of drought

61. Well Cone of Depression
When you draw water from a well, a cone forms, lowering the water table around the well
For a home it’s small, for farm it can be very large
Think of using a straw

62. Wells

63. Groundwater Contamination
If pollution gets into the groundwater, it can spread over a wide amount of space
Over-usage can lower the level of ground water making it harder for everyone around to get water, or for it to be replenished

64. Groundwater Contamination

65. Groundwater Concerns We treat groundwater as a non-renewable
Especially in the Midwest where it cannot connect to the ocean
Why?
Because we depend on rain to replenish it. If we use more than the rain can resupply we can run out of a useful amount
When we pump too much water or it flows quickly, the ground can settle, filling in the empty space

68. Caverns
Groundwater’s ability to weather and erode is mostly seen in caverns
Limestone can break down with water that has a little carbonic acid in it leaving behind chambers underground

69. Carlsbad Caverns

70. Carlsbad Caverns

71. Public Virginia Caves
Luray

72. Public Virginia Caves
Shenandoah

73. Public Virginia Caves
Endless

74. Public Virginia Caves
Skyline

75. Public Virginia Caves
Grand

76. Public Virginia Caves
Dixie
Gap
Natural Bridge

77. Caverns Carbonic acid dissolves the calcite from the limestone
Caves form in the zone of saturation
However the formations we are used to form after the water table has lowered and it is in the zone of aeration instead
The calcium carbonate that is left behind from the limestone is called Travertine

78. Caverns
When water infiltrates through the soil and into the cavern, it comes in from the ceiling
The water drips down over the rock and carries some sediment with it
It deposits that sediment along its path and where it lands
Dripstone is what is created

79. Caverns

80. Karst Topography Areas of land that have been shaped by groundwater
Contain caves, sinkholes, springs, etc
Sinkhole- a depression in the ground where water underground has removed rock making the surface unstable
The water eats out the rock slowly until it can no longer support the rock and soil above it and collapses.

83. Guatemala City – 100 ft deep