Deck 17: Streams and Floods: the Geology of Running Water

Question 1

The figure below shows an example of a ________ drainage network.

A)dendritic
B)radial
C)parallel
D)trellis

Answer 1

C

Question 2

The discharge of a river traveling through a temperate region will typically ________ downstream;the discharge of a river traveling through an arid region will typically ________ downstream.

A)increase;increase
B)decrease;decrease
C)increase;decrease
D)decrease;increase

Answer 2

C

Question 3

Ephemeral streams ________.

A)consist of a series of intertwined channels that are overloaded with sediment
B)have flowing water either episodically or during only a portion of the year
C)have a channel that is highly sinuous (curvy)
D)are those that divert flow from streams they have intersected through stream erosion

Answer 3

B

Question 4

The figure below shows an example of a ________ drainage network.

A)dendritic
B)radial
C)rectangular
D)trellis

Question 5

As the velocity of flow decreases,which of the following is NOT true?

A)The flow tends to become more laminar.
B)The competence increases.
C)Suspended sediment starts to be deposited.
D)The saltation of the bed load may cease.

Question 6

In a region characterized by a parallel series of ridges and valleys,a ________ drainage network is expected.

A)dendritic
B)radial
C)rectangular
D)trellis

Question 7

In a region with prominent orthogonal sets of joints,a ________ drainage network is expected.

A)dendritic
B)radial
C)rectangular
D)trellis

Question 8

Runoff is NOT commonly derived from ________.

A)sheetwash
B)rainfall or snowfall
C)ocean currents
D)groundwater springs

Question 9

Which type of drainage network is associated with badlands topography?

A)dendritic
B)parallel
C)rectangular
D)trellis

Question 10

The region below a streambed where groundwater flows in the same direction as the stream but at a slower rate is termed the ________ zone.

A)low flow
B)vadose
C)water table
D)hyporheic

Question 11

The figure below shows two hypothetical streams that have identical cross-sectional areas but different channel shapes.Assuming all other factors are equal,stream ________ will have the fastest flow because of the difference in ________.

A)A;width
B)A;wetted perimeter
C)B;width
D)B;wetted perimeter

Question 12

The deepest part of a curved stream channel,where the flow is fastest,is called the ________.

A)base level
B)point bar
C)stream gradient
D)thalweg

Question 13

The figure below shows an example of a ________ drainage network.

A)dendritic
B)radial
C)rectangular
D)trellis

Question 14

In uniform sediments with a relatively constant and gentle slope at the surface,a ________ drainage network is expected.

A)dendritic
B)radial
C)rectangular
D)trellis

Question 15

The figure below shows an example of a ________ drainage network.

A)dendritic
B)radial
C)rectangular
D)trellis

Question 16

The figure below shows an example of a ________ drainage network.

A)dendritic
B)radial
C)rectangular
D)trellis

Question 17

Along a large cone-shaped volcano,a ________ drainage network is expected.

A)dendritic
B)radial
C)rectangular
D)trellis

Question 18

The primary stream fed by tributaries within a dendritic drainage network is termed a ________ stream.

A)lead
B)trunk
C)taproot
D)pirate

Question 19

Along a uniform and steep slope of relatively weak substrate,a ________ drainage network is expected.

A)dendritic
B)parallel
C)rectangular
D)trellis

Question 20

Which river has the greatest discharge of any stream on Earth?

A)Nile
B)Mississippi
C)Congo
D)Amazon

Question 21

The flat-lying area surrounding a river channel is termed the ________.

A)base level
B)floodplain
C)stream gradient
D)thalweg

Question 22

What physical property of the underlying rock would lead to the formation of a cliff over which a waterfall may form?

A)a high resistance to erosion
B)high porosity
C)large permeability
D)very fine grain sizes

Question 23

V-shaped stream valleys result from the downcutting of stream erosion and ________.

A)mass wasting on the valley sides
B)isostatic rebound
C)the topographic rule of V's
D)conservation of angular momentum

Question 24

The distinction between a valley and a canyon is ________.

A)nonexistent;the two terms are synonymous
B)that the sides of a canyon are more steep than those of a valley
C)that the sides of a valley are more steep than those of a canyon
D)that valleys are often cut by streams,whereas canyons are eroded by the wind

Question 25

The slope of a stream surface measured between two points along its course is the ________.

A)base level
B)floodplain
C)gradient
D)thalweg

Question 26

The base level of a tributary would become ________ if a dam and a reservoir were constructed where it flowed into a trunk stream.

A)lower
B)slower
C)faster
D)higher

Question 27

All else being equal,water will flow faster in a stream with ________ and a ________ wetted perimeter.

A)well-developed meanders;small
B)well-developed meanders;large
C)a straight channel;small
D)a straight channel;large

Question 28

Meandering streams ________.

A)consist of a series of intertwined channels that are overloaded with sediment
B)have flowing water either episodically or during only a portion of the year
C)have a channel that is highly sinuous (curvy)
D)are those that divert flow from streams they have intersected through stream erosion

Question 29

Moving away from its headwaters/source,the flow of a stream usually becomes more ________.

A)turbulent
B)chaotic
C)competent
D)laminar

Question 30

The outer edge of a meander,where material is being eroded,is a(n)________.

A)meander neck
B)cut bank
C)point bar
D)abandoned meander

Question 31

The figure below shows a road in Death Valley,California,curving around a(n)________.

A)natural levee
B)river delta
C)alluvial fan
D)braided stream

Question 32

Within a meander,where is sediment most likely to be deposited?

A)on the outer banks of the meander
B)on the inner banks of the meander
C)uniformly to either side of the meander
D)directly in the middle of the meander

Question 33

The total sediment load of a stream consists of all of following EXCEPT the ________ load.

A)turbulent
B)suspended
C)bed
D)dissolved

Question 34

The stream gradient of most rivers ________.

A)is greater near the source than near the mouth
B)is greater near the mouth than near the source
C)does not change significantly as a river flows downstream
D)is greater for a meandering stream than for any other type

Question 35

All else being equal,water will flow faster in a stream that has a ________,which is typically found near the river's ________.

A)steep stream gradient;source
B)steep stream gradient;mouth
C)gentle stream gradient;source
D)gentle stream gradient;mouth

Question 36

A small mountain stream will have a ________ competence and a ________ capacity than the Mississippi River.

A)lower;lower
B)lower;greater
C)greater;greater
D)greater;lower

Question 37

Ultimately,the base level of a stream valley can be no lower than ________.

A)the average elevation of the continent on which it is found
B)sea level
C)the average elevation of the local catchment
D)the maximum elevation of the local catchment

Question 38

The inner edge of a meander,where sediment is deposited,is a(n)________.

A)meander neck
B)cut bank
C)point bar
D)abandoned meander

Question 39

The lowest elevation to which a stream can downcut is the ________.

A)base level
B)floodplain
C)stream gradient
D)thalweg

Question 40

The figure below is an aerial photograph of a meandering stream.The light-colored features labeled with arrows below are ________.

A)thalwegs
B)cut banks
C)flood plains
D)point bars

Question 41

Pirate streams ________.

A)consist of a series of intertwined channels that are overloaded with sediment
B)have flowing water either episodically or during only a portion of the year
C)have a channel that is highly sinuous (curvy)
D)form when headward erosion causes one stream to intersect another

Question 42

The shape of a delta is primarily determined by ________.

A)the shape of the river channel near the mouth
B)the average grain size of the suspended and bed loads
C)whether river currents,wave-driven currents,or tidal currents are locally predominant
D)the type of rock that is weathering at the outcrop near the headwaters of the river

Question 43

A meander that is cut off to become completely isolated from the main channel but which retains water is a(n)________.

A)meander neck
B)cut bank
C)oxbow lake
D)thalweg

Question 44

If a 50-year flood occurs on the Mississippi River this year,what is the probability that a flood of the same magnitude will occur in the following year?

A)zero
B)1%
C)2%
D)50%

Question 45

With time,a river may erode terrain to produce a low-lying plain that lies close to the base level,which is termed a(n)________.

A)astral plain
B)antedeluvial plain
C)peneplain
D)plateau

Question 46

Braided streams ________.

A)consist of a series of intertwined channels that are overloaded with sediment
B)have flowing water either episodically or during only a portion of the year
C)have a channel that is highly sinuous (curvy)
D)are those that divert flow from streams they have intersected through stream capture

Question 47

Geological evidence suggests that many millions of years ago,the Amazon basin drained toward the west rather than the east.What caused this drainage reversal?

A)a rise in the global sea level
B)a lowering in the global sea level
C)the rise of the Andes Mountains
D)global climate change

Question 48

Which river is a threat to capture the flow of the Mississippi River through avulsion and stream piracy?

A)the Missouri River
B)the New River
C)the Atchafalaya River
D)the Zydeco River

Question 49

Which of the following is NOT true? A 100-year flood ________.

A)has a 1% chance of occurring in any given year
B)is more destructive than a 50-year flood
C)cannot occur in successive years
D)is based on the average recurrence interval of past floods for a particular stream

Question 50

A "bird's foot" delta configuration,similar to that of the Mississippi River delta,forms when the ________.

A)oceanic current exceeds the river current
B)oceanic current is so strong that all sediment is removed as it arrives
C)river and oceanic currents are equal
D)river current exceeds the oceanic current

Question 51

At a river delta,which of the following is NOT true?

A)The stream gradient decreases.
B)A single channel breaks into multiple,radiating distributary channels.
C)The competence decreases.
D)The stream channel becomes very straight because of the large sediment load.