Running Water

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Running Water
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Running water and its energy

• Running water is the Earths most effective form
  of erosion.
  
• Rain
• Snow
• Other precipitation
• Running water comes together to form
• Mississippi
• Amazon

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Running water attacks bedrock

• Abrasion the grinding action of running water
  breaking up the bedrock over which its flows
  primarily by mechanical mean. Using sand,
  pebbles, and even boulders as its cutting tools.
• It is not just abrasion that allows this to
  happen, even fast running water or just the
  chemical make up allows this process to happen as
  well.

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Abrasion
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Water removes weathered rock

• Rivers carry rocks away in three forms
• Solution (A) material that has dissolved from
  bedrock
  
• Suspension (C) material that is suspended in
  the water sand, silt, clay
  
• Bed loads (B) materials that are too heavy to
  be suspended in the water large pebbles, rocks,
  boulders these will just move along the stream
  bed.

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Load of the stream
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Carrying power and load

• Carrying power of a stream is indicated by both
  the total amount of sediment in the stream and by
  the size of the particles being moved by the
  stream.
• Discharge the volume of water flowing through a
  given part at a given time.
  

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Speed of the stream

• Factors that effect the streams speed
• Steepness, or gradient of its beds
• Increased discharge

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V- Shaped Valleys and Canyons

• Valleys with very steep, almost vertical sides
• How are these formed?
• Time depends on the kind of rocks
• Amount of water sediment in the river
• The climate of the area
• As well as several other factors

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V Shaped
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Stream stage youthful
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Stream Stage Maturity
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Stream stages mature
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Base Level Widening the Valley

• This level of a stream cannot cut its bed any
  lower than the level of the stream, river, or
  body of water into which it flows.
  
• As a stream approaches the base level
• The slope and speed decrease
• The stream cuts into the bed slower
• The valley walls are still undergoing weathering
• The result is a wider valley with a broad floor
  and gentle slopping walls

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Lengthening the Valley

• Gully when the rain ends, the stream will
  disappear, but the small valley remains.
  

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Divides and Drainage Basins

• Divide the high land that separates one gully
  from the next, or one river from the next

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River system

• A river and all of its tributaries is a river
  system
  
• Drainage basin, watershed, of a river includes
  all of the land that drains into the river,
  either direction through it tributaries.
  

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Stream Piracy

• Stream piracy or stream capture, is a result of
  the lengthening of a river by headward erosion.
  
  
• Headward erosion wearing away of land at the
  gully
  

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What happening in Stage 1?

• Beaverdam Creek, Gap Run, and Goose Creek flow
  eastward through the Blue Ridge and enter the
  Potomac

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Stage 1
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What is happening in stage 2?

• As the land is eroded downward, the three east
  flowing creeks do not have the power to erode as
  far through the Blue Ridge as the Shenandoah,
  Potomac system. The Shenandoah extends itself
  southward by headward erosion through the
  relatively high land west of the Blue Ridge. It
  eventually captures Beaverdam Creek

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Stage 2
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What is happening in stage 3?

• The capture of Beaverdam Creek added more
  discharge to the Shenandoah which was able to
  therefore erode more. Headward erosion leads to
  the capture of Gap Run. The water gaps where
  Beaverdam Creek and Gap Run used to flow through
  the Blue Ridge are left as wind gaps.

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Stage 3
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What is happening in stage 4?

• Eventually Goose Creek is captured as well.
  Snicker's Gap, Ashby Gap, and Manassas Gap are
  left as wind gaps. As the land on either side of
  the ridge is eroded down together with the ridge
  summit, the relative elevation of the wind gaps
  becomes higher and higher.

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Stage 4
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Water Gap

• A narrow cut that forms in the ridge through
  which the river runs
  
• Occasionally a gap occurs without any river in
  it. This abandoned water gap is a wind gap.
  

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Waterfalls and Their Recession

• Potholes- as sand, pebbles, and small boulders
  swirl around in the whirlpools, they grind deep
  oval or circular holes.
  
• Plunge Pools very large potholes

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Potholesandplunge pools
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Waterfalls and their recession

• Waterfalls can occur when glaciers erode away one
  valley more deeply than others.
  
• Undermining the way in which streams erode at
  waterfalls
  

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Whirlpool action at Niagara?

• Yes this action rapidly erodes the weak shale
  at the base if the falls.
  
• This erosion undermines the tough dolostone
  layer at the top.
  
• From the time the dolostone breaks off, and the
  waterfall recedes.

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Niagara Falls
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Whirlpool action

• As the water falls you can see what effects it
  has on the different rock layers
  

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Meanders and Oxbow Lakes

• Oxbow lake when you have deposits that have
  complete separated from the rivers meanders.

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Mississippi River Delta
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Deltas and Alluvial Fans

• Delta is a deposit from the river where it meets
  the mouth
  
• Alluvial fans are found on sloped surfaces, and
  the sediments are coarser in nature.

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Alluvial Fans
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Flooding here broke through the levee