Lecture 5 - River Flashcards
Deposition River Development (3 phases):
- Headwater –> Floodplain
- Floodplain
- Sediment Deposition
Headwater –> Floodplain (in terms of erosion)
Headwater erodes and the Floodplain is the deposit
What Does the Floodplain Have to do With the River Development
Increases in the size of the river sorting sediments gravel islands in braids
What Does the Sediment Deposition Have to do With the River Development
- Levies create barriers to flow
- Formation of swamps, marsh, oxbow lakes, and second degree channels
What Do Levies Lead to:
- Increased heterogeneity
- Increased biodiversity
Changes During the Transition to a Floodplain River (6):
- Increased Depth/width
- Increased Turbidity then decreased turbidity
- Plants transition from submerged to emerged
- Formation of swamps
- Plankton community
- Lake-like floodplain
River Development/Maturation (Physical Conditions):
- Order: low (1-3), medium (4-6), high (>6)
- Velocity: high, lower, slow
- Width and Depth: low, intermediate, large
- Hydrology: vertical erosion, lateral erosion/transport, deposition
- Clarity: clear, somewhat turbid, turbid
- Light: low, higher, low
- Temp: low, intermediate, warmer
River Development/Maturation (Chemical Conditions):
- Organic Carbon: (low order) alloch. (medium order) alloch. and autochthonous, (high order) autochthonous
River Development/Maturation (Biological Conditions):
- Plants: (low order) low, (medium order) high, (high order) low
- Plankton: low, intermediate, high
- Feeding guide: shredders, grazers, collectors
River Continuum Concept (Upstream Properties):
- CPOM
- Shredders
- Riverine
River Continuum Concept (Downstream Properties):
- FPOM
- Collectors
- Lacustrine
Depositional River - Floodplain Heterogeneity Leads to Three Different Things:
Sorted sediments –> Heterogeneity of habitats –> High Biodiversity
- Avulsion
What is Avulsion:
Rapid abandonment of a river channel —> formation of a new channel and potential flooding
