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

Question 1

In the region immediately surrounding an isolated volcano,a ____________ drainage network is expected.

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

Answer 1

B

Question 2

Scientists have determined that Mars has actively flowing water-filled stream channels.

Answer 2

False

Question 3

Which has greater competence?

A)a small mountain stream
B)the Mississippi River

Answer 3

B

Question 4

The discharge of a river traveling through a humid 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

Question 5

All flowing water on the continents' surfaces is confined to stream channels.

Question 6

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 7

The deepest part of the channel,where the stream flows fastest,is the ____________.

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

Question 8

The primary stream fed by tributaries within a drainage basin is termed a ____________.

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

Question 9

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

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

Question 10

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

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

Question 11

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 the river flows downstream
D)is greater for a meandering stream than for any other type

Question 12

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 13

Although the Nile River is longer,the Amazon River has the greatest discharge of any stream on Earth.

Question 14

Ephemeral streams ____________.

A)consist of a series of intertwined channels that are overloaded with sediment
B)have flowing water either episodically or during 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 15

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 ocean basins

Question 16

As the velocity of flow decreases,____________.

A)flow tends to become more laminar
B)the maximum flow velocity decreases
C)suspended sediment starts to be deposited
D)All of the above are correct.

Question 17

Which has greater capacity?

A)a small mountain stream
B)the Mississippi River

Question 18

All the water in rivers and streams arrives directly from rainfall runoff.

Question 19

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

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

Question 20

The sediment load of a stream consists of only those grains that are fine enough to stay in suspension.

Question 21

Moving away from its headwaters,the flow of a stream usually becomes more ____________.

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

Question 22

At a waterfall,where two sedimentary lithologies are juxtaposed,which lithology is more likely to form the cliff over which the water falls?

A)sandstone
B)shale

Question 23

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

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

Question 24

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 25

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

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

Question 26

The deltas of all major rivers consist of multiple radiating lobes of sediment in a "bird's foot" configuration,similar to the Mississippi River delta.

Question 27

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

Question 28

The distinction between a valley and a canyon is ____________.

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

Question 29

If a stream cuts through flat-lying sediments to reach an anticline produced in an ancient orogenic event,the course of the stream will likely be unaffected.

Question 30

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

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

Question 31

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

A)Old Muddy River
B)New River
C)Atchafalaya River
D)Zydeco River

Question 32

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)abandoned meander

Question 33

Meandering streams ____________.

A)consist of a series of intertwined channels that are overloaded with sediment
B)have flowing water either episodically or during 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 34

All else being equal,water will flow faster in a stream that has a ____________.

A)steep stream gradient
B)gentle stream gradient

Question 35

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 outcrop near the headwaters of the river

Question 36

Braided streams ____________.

A)consist of a series of intertwined channels that are overloaded with sediment
B)have flowing water either episodically or during a portion of the year
C)have a channel that is highly sinuous (curvy)
D)are antecedent

Question 37

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 38

At a delta,____________.

A)stream gradient decreases
B)a single channel breaks into multiple,radiating distributary channels
C)A and B are both correct.
D)None of the above are correct.

Question 39

Geological evidence suggests that many millions of years ago,the Amazon flowed toward the west rather than the east.

Question 40

All else being equal,water will flow faster in a stream with ____________.

A)well-developed meanders
B)a straight channel

Question 41

With time,a river may erode terrain to produce a low-lying plain termed a(n)____________.

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

Question 42

All flooding events occur so rapidly that there is no time to alert people in harm's way.

Question 43

A 100-year flood is more catastrophic than a 50-year flood.

Question 44

Pirate streams ____________.

A)consist of a series of intertwined channels that are overloaded with sediment
B)have flowing water either episodically or during a portion of the year
C)have a channel that is highly sinuous (curvy)
D)have increased their drainage areas

Question 45

If a 50-year flood occurs on the Mississippi River in 2010,what is the probability that a flood of the same magnitude will occur in 2011?

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