Chapter 10

Question 1

Drainage basins are bowl-shaped depressions with a lake in the middle, and all streams in the basin discharge their water and sediment into that lake. (T/F)

Answer 1

False

Question 2

A trellis stream pattern consists of parallel main streams with short tributaries meeting them at right angles. (T/F)

Answer 2

True

Question 3

Stream erosion and deposition are controlled primarily by a river’s velocity. (T/F)

Answer 3

True

Question 4

Low stream velocity generally results in erosion and transportation of sediment. (T/F)

Answer 4

False

Question 5

Stream discharge is one of the most important factors that controls stream velocity. (T/F)

Answer 5

False

Question 6

Hydraulic action refers to the ability of flowing water to pick up and move rock sediment. (T/F)

Answer 6

True

Question 7

A stream reaches its maximum velocity close to the shoreline. (T/F)

Answer 7

False

Question 8

The discharge of a stream is the volume of water that passes a given point in unit of time (ex. 50 cubic meters per second). (T/F)

Answer 8

True

Question 9

A bar in a river channel is a ridge of sediment, usually sand and gravel, deposited in the middle or along the banks of a stream. (T/F)

Answer 9

True

Question 10

Braided streams flow in a network of interconnected rivulets around numerous bars. (T/F)

Answer 10

True

Question 11

Point bars are sandbars deposited in the middle of river channels. (T/F)

Answer 11

False

Question 12

A cutoff meander can become an oxbow lake. (T/F)

Answer 12

True

Question 13

Stream-dominated river deltas, like the Mississippi, display the characteristic triangular shape of a delta. (T/F)

Answer 13

False

Question 14

An alluvial fan is a fan- or cone shaped pile of sediment that forms where a stream emerges from a narrow mountain canyon. (T/F)

Answer 14

True`

Question 15

The process of deepening a valley by erosion of the streambed is called downcutting. (T/F)

Answer 15

True

Question 16

Paved areas and storm sewers decrease the rate of surface runoff water. (T/F)

Answer 16

False

Question 17

A stream can lengthen its valley by headward erosion. (T/F)

Answer 17

True

Question 18

The gravel bed load of a stream moves by ___.

Answer 18

sliding and rolling

Question 19

___ are low ridges of flood deposited sediment that form on both sides of a stream channel and thin away from the channel.

Answer 19

Natural levees

Question 20

A ___ stream flows in a network of rivulets (subchannels) around numerous sandbars.

Answer 20

braided

Question 21

A stream can increase its length by

Answer 21

building a delta
meandering
headward erosion

Question 22

A ridge or strip of ground separating one drainage basin from another is termed a ___.

Answer 22

divide

Question 23

A ___ is the body of a sediment deposited at the mouth of a river when the river’s velocity decreases.

Answer 23

delta

Question 24

Rivers may develop pronounced sinuous (wiggly) curves called a ___ pattern.

Answer 24

meandering

Question 25

A cutoff meander may become a crescent shaped ___.

Answer 25

oxbow lake

Question 26

The ___ is the total area drained by a river and its tributaries.

Answer 26

drainage basin

Question 27

The limit to downcutting of a stream is called the ___ level.

Answer 27

base

Question 28

In North America, the ___ separates streams that flow into the Pacific Ocean from those that flow into the Atlantic Ocean and Gulf of Mexico.

Answer 28

Continental Divide

Question 29

___ influences the velocity of a river along with gradient

Answer 29

Channel shape and roughness

Question 30

___ meanders are meanders that retain their sinuous pattern as they cut vertically downward below the level at which they originally formed.

Answer 30

Incised

Question 31

A graded stream can be deepening its channel by down cutting while parts of its energy is also widening its valley by ___ erosion.

Answer 31

laterial

Question 32

A ___ is a step like landform found above a stream and its floodplain. It is a remnant of an older flood plain or river eroded flat surface.

Answer 32

stream terrace

Question 33

A ___ stream is one that exhibits a delicate balance between its transporting capacity and the sediment load available to it.

Answer 33

graded

Question 34

Flood control structures along the Mississippi River surrounding New Orleans are predominantly ___ .

Answer 34

artificial levees

Question 35

The process of deepening a valley of erosion of a streambed is called ___ .

Answer 35

down cutting

Question 36

A ___ drainage pattern of a river resembles a tree.

Answer 36

dendritic

Question 37

___ are sudden localized floods of large volume and short duration, often triggered by heavy rainstorms.

Answer 37

Flash floods

Question 38

Deltas may be river dominated, tide dominated, or ___ .

Answer 38

wave dominated