1. The Water Cycle, Streams, and Ground Water
Water Systems
The Water Cycle, Streams, and Ground Water

2. Earth’s Water Supply

3. Water Cycle
movement of water between the atmosphere, the land, and the oceans.

4. Evaporation
Water changing from liquid phase to a gaseous phase(water vapor) without boiling.
Surface 2/3 Water
500,000 km3 /year
Evapotranspiration – evaporation from plant leaves.
That’s 200 million Olympic sized swimming pools.

5. Condensation change of state from a gas to a liquid
When water vapor rises in the atmosphere, it expands and cools.
As the vapor becomes cooler; some of it condenses back to liquid
High – Clouds
Low – Fog
Surface - Dew

6. Precipitation
Any form of water that falls to Earth’s surface (rain, snow, sleet, and hail)
Most precipitation falls on Earth’s oceans.
The rest falls on land and becomes runoff or infiltrates the soil to become groundwater.

8. Runoff Rain that falls to the ground and is not absorbed
Moves along the surface of the land until it flows into a stream system
Causes erosion.

9. Factors Affecting Runoff
 Rate of rain  Runoff
 Slope  Runoff
 Buildings  Runoff
 Plants Runoff

10. River Systems
watershed (AKA basin) the area of land that is drained by a river system
The ridges or elevated regions that separate watersheds are called divides.
tributaries streams that flows into a lake or into a larger stream
A river system is made up of a main stream and tributaries.

12. Mississippi River Basin

13. Moosehead Lake Watershed
Contains:
31 lakes
549 m2 of land
400 miles of rivers and streams
empties out into the Atlantic Ocean

14. River Systems
Channel - Depression that a stream follows as it flows downhill
Banks - The edges of a stream channel that are above water level
Bed - The part of the stream channel that is below the water level
A stream channel gradually becomes wider and deeper as it erodes its banks and bed.

15. River Systems stream load - Sediment carried by a stream
Stream load takes three forms
suspended load
bed load
dissolved load

16. Stream Load

17. River Systems
Stream gradient the change in elevation over a given distance
Near the headwaters, or the beginning of a stream, the gradient generally is steep.
As the stream nears its mouth, its gradient often becomes flatter.
The characteristics of streams with different gradients are very different

18. Gradient

21. River Systems River systems change continuously because of erosion.
Depending on the slope of the land, streams have three stages of development. Young, Mature, and Old
These differing streams support different types of organisms

22. Young Streams Flow swiftly through a steep valley.
Lots of whitewater and waterfalls because they have not yet eroded all the material in their way.
Young streams erode most on the bottom and less on the sides.

23. Qualities
Fast Moving
High oxygen
Cold
Little Nutrients

26. Stream Merging
Many young streams join together to form larger streams.
Depending on the slope of the land and the amount of water they will form either mature or old streams

27. Mature and Old Streams
Mature and Old Streams flow through floodplains.
floodplain an area along a river that forms from sediments deposited when the river overflows its banks
Occurs when water levels increase depending on the amount of rainfall and snowmelt in the watershed.

28. Floodplains

29. Mature Streams Curving streams that flow down a gradual slope
Erode more on their sides than on the bottom.
This leads to the creation of meanders (curves in a stream)

30. Qualities Lots of sediment/nutrients Slow moving
Erosion from young streams
Slow moving
Algae can grow

31. Evolution of Mature Streams
meander
When a river rounds a bend, the velocity of the water on the outside of the curve increases.
Increase erosion
On the inside of the curve, the velocity of the water decreases.
Increased deposition
Causes curves to widen

32. Stream Flow

35. Horseshoe Bend of the Colorado River near Page, AZ

36. Oxbow Lakes
The curve enlarges while further erosion takes place on the opposite bank, where the water is moving more quickly.
Meanders can become so curved that they almost form a loop, separated by only a narrow neck of land
This can eventually become separated into an oxbow lake

41. Old Streams
Old streams flow very slowly through a broad flat floodplain.
Usually they have lost their meanders and flow more straightly.

42. Deltas and Alluvial Fans
Fan-shaped masses of sediment deposited as a stream slows
Deltas occur where streams meet oceans
Alluvial fans result where streams loose energy as the slope decreases rapidly.

46. Groundwater
Water that absorbs into the ground and is located in the spaces between sediments (pores)
These pores are connected and allow water to flow through them.

48. Permeability
Ability of a material(rock/sediment) to allow water to flow through it.
Permeable rock/sediment layers allow water to pass through easily
Impermeable rock/sediment layers resist the flow of water.
Depends on size and shape of sediment

49. Zone of Saturation
Ground water fills the pores in the permeable rock/sediment layer creating an aquifer.
The area of the soil where all of the pores have completely filled with water is referred to as the zone of saturation.
The upper limit of this zone is called the water table.

51. Wells Holes that are dug below the water table.
Water has been filtered by sediment.
If water table drops (drought) it can dry up the well.
Too many wells in one area can also lower the water table

53. Artesian Wells
Special kind of well where water is pushed up to the surface naturally.
Require a special kind of geography where an aquifer is sandwiched between impermeable layers and the layers change in elevation.
Gravity creates pressure that forces water up artesian wells.

55. Springs Springs can exist where the groundwater reaches the surface
Some times cracks allow natural artesian wells to form.
Freshwater springs exist along coasts where fresh ground water enters the ocean.

60. Hot Springs and Geysers
Occur where groundwater is stored near hot rocks
Hot springs - near boiling water leaks up to the surface.
Geysers - boiling water and steam is periodically released causing a stream of hot water to shoot out of the ground.

64. Caves and Sinkholes Form as carbonic acid dissolves limestone.
Caves are structurally stable and do no collapse.
If soil above a cave is weak and it collapses into a sinkhole.
People pumping water out can turn caves into sink holes

66. Stalactites and Stalagmites
Little CO2 in caves, carbonic acid breaks down, can’t hold dissolved limestone.
Limestone accumulates as water drips
Stalactite - ceiling of the cave
Stalagmite - ground of the cave

70. Adaptations
Animals must have special adaptations to deal with living in a cave
Dark
No plants
Wet
Dangerous Chemicals