Water

1
Water

• Earths Changing Surface

2
Running Water

• The major agent of the erosion that has shaped
  Earths land surface.

3
Runoff

• Water that moves over Earths surface.
• Amount of runoff in an area depends on
• Amount of rain
• Vegetation
• Type of Soil
• Shape of the land
• How people use the land

4
Generally

• More runoff, more erosion

5
The Course of a River

• Runoff moves down hill and forms rills and
  gullies
• Gullies join together to form a stream
• Stream grow larger and combine with other streams
  and rivers called tributaries.

6
Rills and Gullies
7
Streams and Rivers

• Stream a channel along which water is
  continually flowing down a slope.

8
Tributary

• Tributary a stream or river that flows into a
  larger river.
• Example Wisconsin River is a tributary to the
  Mississippi

9
Erosion by Rivers

• Waterfall occur where a river meets an area of
  rock that is very hard and erodes very slowly.
• The water then flows over softer rock downstream

10
(No Transcript)
11
Flood Plain

• The river usually flows over more gently sloping
  land.
• The river spreads out and erodes the land,
  forming a wide river valley
• Flood Plain the flat, wide area of land along a
  river.

12
(No Transcript)
13
Meanders and Oxbow lakes

• Meander a loop like bend in the course of a
  river
• Oxbow lake a meander that has been cut off from
  the river.

14
(No Transcript)
15
Deposits by Rivers

• Deposition creates landforms!
• Alluvial Fans
• Deltas
• It can also add soil to a rivers flood plain

16
Alluvial Fans

• A wide, sloping deposit of sediment formed where
  a steam leaves a mountain range.

17
Delta

• Sediment deposited where a river flows into an
  ocean or lake builds up a landform.

18
(No Transcript)
19
Deposition During Floods
20
The Course of a River
21
Groundwater Erosion

• Groundwater water that fills the cracks and
  spaces in underground soil and rock layers.
• Can cause erosion through a process of chemical
  weathering.

22
Caves

• The action of carbonic acid on limestone can
  result in deposition
• Stalactite deposits in caves that hang like an
  icicle from the roof of the cave.
• Stalagmite slow dripping builds up a cone-shape
  from the cave floor.

23
(No Transcript)