The hydrologic cycle

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The hydrologic cycle
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The Water Cycle

• The Water Cycle Animation
• Ground Water

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Sources of Earths water
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RIVER FeaturesHeadwaters

• Beginning of a stream high elevation.

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Watershed

• Land from which water runs off into a stream.

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Tributary

• Feeder stream that flows into a main stream.

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Divide

• Elevated region that separates 2 watersheds.

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Coastal Plain
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Floodplain

• Part of the valley floor that may be covered with
  water during a flood.
• Flood Plain Delineation
• Flood Plain Formation

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Meander - E

• Wide curve in a stream channel.

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Erosion Deposition along a meandering stream
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Oxbow
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Cut Bank - E

• The area of active erosion on the OUTSIDE of a
  meander.

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Point Bar - D

• A crescent-shaped accumulation of sand and gravel
  deposited on the INSIDE of a meander.

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Oxbow

• Water remaining in an isolated meander in a
  floodplain.
• oxbow lake formation

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Upper Mississippi River (Missouri)
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Delta - D

• Fan-shaped deposit of sediments at the mouth of a
  stream formed when rivers erode and transport
  sediments. When the river slows down, it deposits
  sediments.

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Common stream measurements

• Gradient/Slope rise change in elevation
• run
  distance
• Discharge - how much water flows through a river
  in 1 second
• Discharge (l x w x d) / time
• Greater discharge more sediment it can carry
  more erosion it can cause
• Stream Load size of sediment

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Describe sediment carried by streams

• Bed load- heavy sediment, skips along bottom
• Suspended load- small particles, makes water look
  cloudy.
• Dissolved load- minerals (or pollutants) in
  solution
• Load Animation
• Another Animation!
• Stream Velocity Load Deposition

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Describe the 3 ways rivers erode sediment.

• Headward stream lengthening
• Downcutting mountainous areas form v-shaped
  valleys
• Meandering
• Lateral stream widening (occurs more than
  downcutting in flatter areas).
• Formation of a V-Shaped Valley

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How river systems change from young to mature!

• MATURE
• Wide Channels
• Large floodplains
• Lateral erosion
• Gentle slopes
• Meanders, oxbows
• Fine sediment

• YOUNG

• Narrow channels
• Small floodplains
• Downcutting
• Steep slopes
• Rapids, waterfalls
• Coarse sediment

Life Cycle of a River Overview
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Trace the path(s) that 99 of water travels
through the Great Lakes watershed.
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Fig. 19.7, p. 484
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Great Lakes Watershed
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FLOODS

• Stream overflows channel
• Causes
• Weather events
• Dams break
• () Provides fertilizer for floodplain
• (-) Most destructive of all geologic hazards

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Missouri Mississippi Rivers (Satellite view
near St. Louis)
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Same satellite view during flooding in 1993
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Describe human decisions that increase the risk
of flooding.

• Disturbing vegetation that uses water and returns
  it to the atmosphere before flooding occurs.
• Building
• Grazing animals
• Farming practices like clear-cutting land
• Cutting down forests

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FLOOD CONTROL

• Dams

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Fig. 13-12, p. 325
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Glen Canyon Dam, Page, AZ (Lake Powell in
background, Colorado River in foreground)