Chapter 6 - Streams & Flooding

Question 1

What is the hydrosphere?

Answer 1

All the water at and near the surface of the earth.

Question 2

What is a stream?

Answer 2

Any body of flowing water confined within a channel, regardless of size.

Question 3

What is a drainage basin?

Answer 3

The region from which a stream draws water.

Question 4

What is a divide?

Answer 4

It is what separates drainage basins.

Question 5

What is discharge?

Answer 5

The volume of water flowing past a given point.

Question 6

What is a traction load?

Answer 6

Heavy debris that is being rolled, dragged or pushed along the bottom of a stream bed.

Question 7

What is saltation?

Answer 7

Material of intermediate size carried in short hops along a stream bed.

Question 8

What is the suspended load?

Answer 8

It is material that is light enough to be moved along suspended in the stream.

Question 9

What is a dissolved load?

Answer 9

Substances that are completely dissolved in the water of a stream.

Question 10

What is the load?

Answer 10

The total quantity of material that a stream transports.

Question 11

What is a stream capacity?

Answer 11

It is a measure of the total load of material a stream can move. (Closely related to discharge)

Question 12

What is the gradient?

Answer 12

The steepness of a stream channel.

Question 13

What is the base level?

Answer 13

The lowest elevation to which the stream can erode downward.

Question 14

What is the longitudinal profile?

Answer 14

It is a sketch of the stream’s elevation from source to mouth.

Question 15

What is a delta?

Answer 15

It is a large, fan-shaped pile of sediment.

Question 16

What is an alluvial fan?

Answer 16

A similarly shaped feature to a delta, but is formed when a tributary stream flows into a more slowly flowing, larger stream.

Question 17

What is a meander?

Answer 17

It is a kink in a stream formed by erosion.

Question 18

What is a cut bank?

Answer 18

It is where a stream tends to flow faster.

Question 19

What are point bars?

Answer 19

Sediment that is deposited on the inside of meanders.

Question 20

What is a flood plain?

Answer 20

It is the area into which a stream spills over during floods.

Question 21

What is known as infiltration?

Answer 21

When water from precipitation sinks into the ground.

Question 22

What is known as percolation?

Answer 22

When water moves through soil and rock.

Question 23

What is termed the stage of a stream?

Answer 23

The elevation of the water surface at any point.

Question 24

When does a stream crest?

Answer 24

When it’s maximum stage has been reached.

Question 25

What are upstream floods?

Answer 25

Floods that only affect small, localized areas.

Question 26

What are downstream floods?

Answer 26

Floods that affect large stream systems and large drainage basins.

Question 27

What are flash floods?

Answer 27

They are a variety of upstream flood characterized by a rapid rise of stream stage.

Question 28

What are ephemeral streams?

Answer 28

They are streams that only flood occasionally.

Question 29

What does the recurrence interval describe?

Answer 29

How frequently a flood of of a certain severity occurs (on average) for a certain stream.

Question 30

What are retention ponds?

Answer 30

They are large basins that trap some of the surface runoff, keeping it from flowing immediately into a stream.

Question 31

What does channelization mean?

Answer 31

Various modifications of the stream channel itself that are usually intended to increase the velocity of water flow

Question 32

What are levees?

Answer 32

Raised banks along a stream channel.