Streams

1
Ch. 11
Streams Rivers
2
Distribution of Water on Earth
3
Main difference between lakes and streams is flow
Physical effects Chemical effects Biological
effects
4
Physical effects
Flowing water erodes
As a river meanders, carves out some areas,
deposits on others
5
Results in various habitats
http//www.epa.gov/volunteer/stream/images/fig44.j
pg

6
Riffles, pools and runs are all within the main
channel
but lotic systems also have a floodplain
7
Kalff 2002
Hyporheic zone
8
Riparian zone
http//collections.ic.gc.ca/environmental/environm
ent/MNR/rouge_pics/large/L37.jpgpg
9
Chemical effects
No vertical gradients in temperature and oxygen
Have longitudinal effects
10
Biological effects
Periphyton, Aufwuchs, or Biofilm
http//www.esd.ornl.gov/BMAP/images/periphy.jpg
Allochthonous Autochthonous
11
The Importance of Lotic Systems

• Provide water and nutrients for agriculture
• Provide habitat to diverse flora and fauna
• Provide routes for commerce
• Provide recreation
• Provide electricity

12
Existence of lotic systems depends
on Availability of surface water A channel in
the ground An inclined surface
13

• Four dimensions of lotic systems
• Longitudinal
• Lateral
• Vertical
• Time

14
Effect of Climate
Rivers are very dependent on climate and their
characteristics are closely related to the
precipitation and evaporation regimes in their
drainage areas.

• Three types
• Perennial or permanent rivers
• Periodic rivers
• Episodic rivers

15
The Hydrologic Cycle
16
What is A Watershed?
17

• Geomorphology
• Stream Order

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Geomorphology Channel Morphology
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Channel Morphology Cross section of a channel
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Channel Morphology Floodplain
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Channel Morphology Meandering Rivers
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Channel Morphology Meandering Rivers Sinuosity
Gradient Substrate

• Big meanders
• low gradient
• fine substrates

• Small meanders
• high gradient
• coarse substrates

23
Channel Morphology Braided Streams
high slope high stream power coarse bed
materials
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Channel Morphology Riffles, Pools,
Cascades Meander Formation
25
Riffles Pools
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Geomorphology Habitat Scales
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The River Continuum Concept
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Stream Order and the RCC
Low order streams
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Stream Order and the RCC
Mid high order streams
30
Homework Assignment 9
p. 292, Questions 4 6 (10 points) Submit your
answers typed and written in complete sentences.
Explain your answers (i.e. why).