Lecture 7 Flashcards Preview

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Flashcards in Lecture 7 Deck (20):
1

What is a drainage divide?

The high point separating different basins

2

Why is a watershed described as dendritic?

Because it is tree shaped in the way it connects

3

Why is a longitudinal profile important when looking at a river?

It shows slope change over a distance

4

Why are rivers so important to earths topography?

They erode and constantly change landscapes

5

What is a endorheic basin?

A basin that flows into the interior not the ocean

6

What is the fluvial river system?

Run off when precipitation is higher that the rate of soil infiltration creating run off.

7

Why is a river an open system?

It exchanges matter across the boundary
It collects run off
It transports sediment and deposits it into the ocean

8

What three things control a river form and function?

Drainage basin/topography
Flow discharge/ sediment slope
Base level

9

Define base level.

The lowest point in a river, defined by the elevation of the outlet

10

Does the amount of sediment in a river relate to the discharge rate?

Yes

11

Define stream competence.

The ability of a stream to do work, transport different sediment sizes.

12

Define stream capacity.

Ability of a stream to move volume

13

Define entrainment speed.

The required river speed to pick up a particle to initiate inertia. Must overcome friction.

14

Why does clay require a higher entrainment velocity?

Because the small particles have electrostatic energy holding them together as well as friction

15

What does the hjulstrom curve show?

How river velocity and size of sediment are related and result in erosion, deposition and transportation.
It is all dependent around the entrainment velocity

16

What causes river erosion?

When sediment output is greater than sediment input.

17

What are the three types of channel patterns?

Straight
Meandering
Braided

18

What is the thalwag?

The zone of fastest flowing water

19

What is a levee

A build up of sediments on a river bank raising the stream capacity, these can break and cause floods

20

What is a water shed?

A drainage basin.