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Fluvial Systems

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Fluvial Systems River Landforms Physics of Stream Flow Stream velocity - flow velocities are fastest near the center of the stream and slowest near the banks. – PowerPoint PPT presentation

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Title: Fluvial Systems


1
Fluvial Systems
  • River Landforms

2
Physics of Stream Flow
  • Stream velocity - flow velocities are fastest
    near the center of the stream and slowest near
    the banks.
  • Thalweg'- the deepest part of the stream
  • Wetted perimeter - the length of the stream bed
    that is in contact with water.
  • Width - width of the stream at a particular
    point.
  • Depth - depth of the stream at a particular
    location.
  • Reach - any length of a stream

3
Physics of Stream Flow
4
Sediment Transport
  • Suspended Load
  • Bed Load
  • Solution Load

5
Suspended Load
6
Solution Load
  • Think Ocean Water

7
Bed Load
Saltation the process by which particles bounce
along on the botttom of a stream
8
Channel Patterns
  • Depends on
  • Sediment Load
  • High load more likely to be braided
  • Gradient (slope of stream)
  • Low Gradient more likely to be meandering
  • Human activity
  • Most straight channels are caused by human
    activity

9
Straight Channels
  • Inherently unstable
  • Most form sand bars which turn into meanders
  • Dan Neilens work

10
Braided Streams
  • High Gradient
  • Mountainous Regions
  • Common in glaciated landscape
  • Series of interconnected channels separated by
    bars
  • Carries abundant sediment

11
Braided Stream
12
Meandering River
  • Mississippi River!

13
Meandering River
  • Sinuous River with many bends

14
Meandering River
  • Oxbow Lakes

15
Meandering River
  • Oxbow Lakes-how do they form?

16
Meandering River
  • Parts of a river

17
Meandering River
18
Drainage Patterns
  • Influenced by the pre-existing geology and
    geography of a region
  • 3 main types
  • Dendritic
  • Parallel
  • Radial

19
Dendritic
  • Tree-like

20
Parallel
21
Radial
22
Fluvial Landscapes
Controlled by Base Level Body of Water Carrying
capacity What it can carry Controlled by Slope
23
Flood Plains
  • Much of across the river (Arkansas)
  • flat land that lies next to a stream or a river
    that experiences periodic times of flooding

24
Deltas
  • Landform formed where a river flows into a body
    of water, be it the ocean or a lake.
  • River dominated, tide dominated, Wave
    dominated-three things that control delta
    development.
  • Named for Greek Letter Delta, Nile delta looks
    like

25
Deltas
  • River Dominated Mississippi River Delta

26
Deltas
  • Tide Dominated Tides overwhelm freshwater input

27
Deltas
  • Wave Dominated Longshore current carries
    sediment away

28
Alluvial Fans
  • Fan-shaped features - sediment
  • Formed at marked change in slope
  • Mountainous regions
  • Water carried sediment released when slope changes

29
Alluvial Fans
30
How do they match up?
  • Will sketch it on board
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