Deck 14: Running Water: the Geology of Streams and Floods

Question 1

Which has greater capacity?

A) a small mountain stream
B) the Mississippi River

Answer 1

B

Question 2

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

Answer 2

D

Question 3

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

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

Answer 3

A

Question 4

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 those that divert flow from streams they have, through stream erosion, intersected

Question 5

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) are those that divert flow from streams they have, through stream erosion, intersected

Question 6

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

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

Question 7

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 8

Which has greater competence?

A) a small mountain stream
B) the Mississippi River

Question 9

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, through stream erosion, intersected

Question 10

An arroyo refers to ____________.

A) the inner bank of a meander, where sediment is deposited
B) an earthen levee designed to reduce flooding in a portion of the floodplain
C) an ephemeral stream channel that only has discharge after rainfall or snowmelt
D) a point in a stream channel where it is relatively easy to cross

Question 11

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

Question 12

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

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

Question 13

The slope of a stream bed measured at some point along its course is the ____________.

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

Question 14

All else being equal,a deep,narrow stream will flow ____________ a shallow,broad stream.

A) more slowly than
B) more rapidly than
C) at the same rate as

Question 15

In uniform sediments or rock at the surface,a ____________ drainage network is expected.

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

Question 16

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 17

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, through stream erosion, intersected

Question 18

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

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

Question 19

All flowing,as opposed to standing,water on the Earth's surface is confined to stream channels.

Question 20

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

Question 21

A thin strip of land separating abutted cut banks on opposite ends of a meander loop is a(n)____________.

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

Question 22

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 23

Which river threatens to capture the flow of the Mississippi River?

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

Question 24

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 25

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 outcrops near the headwaters of the river

Question 26

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 27

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 28

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

Question 29

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 30

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

A) steep stream gradient
B) gentle stream gradient

Question 31

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%

Question 32

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

Question 33

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 34

The distinction between a valley and a canyon is ____________.

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

Question 35

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

A) well-developed meanders
B) a straight channel

Question 36

A meander that is cut off to become completely isolated from the main channel and that dries up is a(n)____________.

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

Question 37

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

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

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

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 40

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