Stream Development

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Stream Development
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100 Aker Wood
http//www.geocities.com/Hollywood/Hills/2255/pigm
ap.gif
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• By the time it came to the edge of the Forest the
  stream had grown up, so that it was almost a
  river, and, being grown-up, it did not run and
  jump and sparkle along as it used to do when it
  was younger, but moved more slowly.
• For it knew now where it was going, and it
• said to itself, "There is no
• hurry. We shall get there
• some day."

http//www.lavasurfer.com/wtp/pooh-100akermap.html
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• But all the little streams higher up in the
  Forest went this way and that, quickly, eagerly,
  having so much to find out before it was too late.

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Stages of Stream Development
http//dynamic.ou.edu/notes/running_water/running_
water.html
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Young Streams
-steep slope/gradient -high velocity -down
cutting? erosion
http//pinker.wjh.harvard.edu/photos/american_west
/pages/Yosemite20Falls.htm
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Narrow and V-Shaped Valley
http//dynamic.ou.edu/notes/running_water/v-shaped
_valley_ecuador.jpg
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Rapids
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More Mature
Letchworth Gorge- Genesee River
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Mature Streams

• flood plain develops
• lower slope/gradient
• meanders (bends) form

http//dynamic.ou.edu/notes/running_water/running_
water.html
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Meanders of the Keve River, Angola as it crosses
its broad flood plain.
http//www.birdingafrica.com/africa_tours/images/a
ng_kevefloodplain.jpg
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Deep water on outside of meander curve

• http//dynamic.ou.edu/notes/running_water/deep_wat
  er,outsideofmeander,rcky_mt_np_co.jpg

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Old Age Streams
http//www.cox-internet.com/coop/deltawebpage.html
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Erosion and Deposition along a meander
http//dynamic.ou.edu/notes/running_water/erosion,
dep,meander_western_wy.jpg
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OLD Streams
-low slope/gradient -very wide channel and
floodplain -abundant meanders
NIAGARA RIVER
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http//www.uwsp.edu/geo/faculty/ritter/images/lith
osphere/fluvial/meander_GSC_small.jpg
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http//gpc.edu/pgore/myphotos/appalach/meander2.j
pg
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http//dynamic.ou.edu/notes/running_water/low-grad
ient_stream_katmai_ak.jpg
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Oxbow Lakes Form
http//dynamic.ou.edu/notes/running_water/oxbow2.j
pg
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http//www.csus.edu/indiv/s/slaymaker/Archives/Geo
l10L/meanders1.jpg
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Point bar
http//images.google.com/imgres?imgurlhttp//www.
csus.edu/indiv/s/slaymaker/Archives/Geol10L/meande
rs1.jpgimgrefurlhttp//www.csus.edu/indiv/s/slay
maker/Archives/Geol10L/landforms.htmh361w418s
z221hlenstart19tbnidvDkP6x64wC9uRMtbnh10
8tbnw125prev/images3Fq3Dmeander2Bstream26s
vnum3D1026hl3Den26sa3DG
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http//www.cleo.net.uk/resources/displayframe.php?
src309/consultants_resources2F_files2Fmeander4.
swf
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http//geobytesgcse.blogspot.com/2006/11/middle-co
urse-of-river-meanders-ox-bow.html
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DO NOW Factors that cause deposition

• If velocity of a stream or river decreases, what
  will happen to the sediment that the stream or
  river is carrying?
• What happened to the kinetic energy?

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• Is sediment of mixed sizes sorted by streams as
  kinetic energy decreases and velocity slows?

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Deposition

• the process of dropping material as kinetic
  energy of an erosional agent decreases

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Factors causing deposition

• Deposition occurs when the velocity of speed of
  an erosional agent decreases
• Two Factors
• The velocity of the erosional system
• The characteristics of the sediments

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Velocity of an Erosional System and the rate of
deposition

• As velocity decreases, particles are deposited in
  order of their size
• In a fast stream all particles will be
  suspendedas it slows down the particles will be
  deposited in order (from large to small)

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Characteristics of Sediment and the rate of
deposition

• Size- the larger the sediment the faster the rate
  of deposition
• Shape- the mope spherical the sediment the faster
  the rate of deposition
• Density- the greater the density the faster the
  rate of depostion

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Delta- fan shaped deposit of sediments at the
mouth of a river
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DO NOW

• 1. The block diagram below shows a displacement
  of rock layers.Which process describes the
  downward sliding of the rock material?
• A) tidal changes B) glacial erosion C) mass
  movement D) lava flow 
• 2. Create a graph that demonstrates the
  relationship between the distance from a river
  delta into the ocean and the average size of
  sediments deposited on the ocean floor.
• Try to describe the relationship.

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Deposition

• the process of dropping material as kinetic
  energy of an erosional agent decreases
• Stream Deposition Occurs In Areas
• 1. at widening rivers
• 2. on the inside of a curve of a meandering
  stream
• 3. at the mouth of stream/river that flows into a
  larger body of water

As kinetic energy ______________, water velocity
_____________.
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Horizontal Sorting

• Horizontal sorting- As water slows gradually,
  smaller and smaller particles drop out causing
• Gradual
• decrease in
• velocity

Sorting Animation McDougal Sorting Animation
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Vertical Sorting

• Occurs when water velocity decreases suddenly
• Examples
• -Flash flooding
• -Spring thaw
• -frozen ground does not allow for snow melt or
  rain water to penetrate soil which leads to
  increased runoff into streams/rivers

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Graded Bedding

• From repeated sorting events
• Ex. Annual (yearly) spring thaws
• Seasonal melting of glaciers

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Graded Bedding
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Wind- Crossbedding
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GLACIER- Graded bedding in a glacial esker.
Medina NY July 2004
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Glacial TILL- UNSORTED
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Normal Wave conditions- cross bedding
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Hurricane waves and tsunami Waves- graded bedding
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DO NOW

• Please take out Deposition in Streams Questions

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DO NOW
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How do size, shape and density affect the
settling times of sediment? How do size, shape
and density affect settling (deposition) rates of
sediment?