5.12. (9/23) Fluvial System; Basic Channel Hydrology Flashcards
river and channel types
1
Q
where is sediment-moving water gathered?
A
in drainage basins
2
Q
What is a drainage basin?
A
- catchment
- where precipitated water gathers
3
Q
What do rivers do with the water?
A
- conduits in catchments to move water into ocean
- pick up and move sediment
4
Q
What are headwaters?
A
- sediment factory
- creep, debris flows, landslides
- move sediment to transfer zone
5
Q
What are transfer zones?
A
- sediment and water carried by river channels
6
Q
What are depositional zones?
A
- deltas, beaches, offshore to shallow marine environment
7
Q
What are the characteristics of the meandering channel pattern?
A
- carries fine-grained mud
- sticky banks
- stable discharge: same amount of water every day
- low slope
8
Q
What are the characteristics of the braided channel pattern?
A
- coarse (sand and gravel) sediments
- loose/unstable banks (fall apart all the time)
- varied discharge: a lot of water one day and not a lot the next
- steep slope
- frequent shifting of sediment, vegetation cannot establish
9
Q
What is discharge?
A
volume of water moving per unit time
*cubic meters per second
10
Q
What kind of channel is a pool and riffle?
A
- deep pools
- shallow riffles
- step slope
- rocks transverse to flow (bubbling rapids)
- coarse-grained (sand and gravel)
- some mud
- steep slope
- headwaters and transfer zones
- Saucon Creek (many in Pennsylvania)
11
Q
What is a point bar?
A
- landform that is made in big meandering loops
- as the river goes around a meandering loop, it deposits sediment whose shape points out into the channel
- inclined surfaces violate steno’s laws
- sediment accumulates laterally/horizontally
12
Q
What is lateral accretion?
A
- sequential build-up in a lateral way
- sediment accumulates in a lateral way and builds out into the channel horizontally
13
Q
What pushes a channel to build its looping meanders?
A
lateral accretion
14
Q
What is a levee?
A
- natural mounds of sediment that form at the edges of meandering channel
- help confine water
- part of the point bar system
- occur there because as the water rises in the channel, as soon as it flows out - speed falls, depth falls, sediment gets dumped
- sediment accumulates vertically
15
Q
How do things move in the floodplains?
A
Settling
