Earth: An Introduction to Physical Geology, 11e (Tarbuck)
Chapter 16 Running Water
16.1 Multiple-Choice Questions
1) What is infiltration?
A) The transition from liquid to gas as a result of increases in temperature
B) Plants taking in water
C) Water soaking into the ground
D) Water running off the surface and entering a channel
2) The ________ describes the path water takes as it moves between the land, the ocean, and the
atmosphere.
A) Hydrologic Cycle
B) Oxygen Cycle
C) Rock Cycle
D) Matter State Cycle
3) What percentage of Earth’s water is in the form of seawater?
A) 2.15%
B) 97.2%
C) 0.62%
D) 0.03%
4) What is the geologic definition of a stream?
A) A river of water that carries large volumes of water and has many tributaries
B) A stagnant body of water with little current and low oxygen content
C) A large lake system
D) A channelized body of water flowing down gradient
5) The ________ is an elevational point that divides an entire continent into large drainage
basins.
A) Appalachian Mountains
B) Continental Divide
C) Watershed
D) Sediment production zone
6) ________ is the area at the headwaters of a stream where most of the sediment is derived.
A) Sediment Production
B) Sediment Transport
C) Sediment Deposition
D) Sediment Load
7) Which of the following is not one of the three zones of a river system?
A) Sediment Capacity Zone
B) Sediment Transport Zone
C) Sediment Deposition Zone
D) Sediment Production Zone
8) What is the wetted perimeter of a stream?
A) That part of a streambed that contains the strongest current
B) Where the stream is incising on the outside of a meander loop
C) Where deposition occurs in an abandoned stream channel
D) The amount of flow in contact with the banks and bed of the channel
9) What is the longitudinal profile?
A) The cross-sectional area perpendicular to the direction of flow
B) The cross-sectional area from the headwaters to the mouth
C) The slope of the stream channel from headwaters to the mouth
D) The probability of a specific stream discharge occurring in a given year
10) How will channel velocity change along the longitudinal profile of a stream?
A) Velocity will remain constant for the entire length of the stream
B) Velocity will start high and gradually decrease toward the mouth due to increasing discharge
downstream
C) Velocity will start low and gradually increase toward the mouth due to increasing discharge
downstream
11) What is the mouth of a stream?
A) The location where one stream flows into another stream
B) The location where streamflow begins
C) The location where streamflow ends
D) The location where streams diverge into distributary channels
12) Which of the following beds would be easiest for a stream to erode?
A) Lined with gravel and cobbles
B) Bedrock
C) Lined with sand and gravel
D) Lined with silt
13) ________ occurs when a rock is gradually dissolved by flowing water.
A) Abrasion
B) Corrosion
C) Quarrying
D) Exfoliation
14) Which of the following particle sizes is most likely to make up a stream’s suspended load?
A) Gravel
B) Clay
C) Sand
D) Silt
15) Which part of a stream’s sediment load moves the slowest?
A) Bed Load
B) Dissolved Load
C) Suspended Load
16) ________ is the maximum load of solid particles a stream can transport per unit time.
A) Corrosion
B) Capacity
C) Competence
D) Carbonate
17) ________ is a measure of a stream’s ability to transport particles based on size rather than
quantity.
A) Corrosion
B) Capacity
C) Competence
D) Carbonate
18) In terms of competence, if the velocity of the stream triples, the impact force of the water
will increase ________ times.
A) Two
B) Three
C) Nine
D) Eighteen
19) During what periods would streams see the greatest erosion and transportation of sediment?
A) Floods
B) Droughts
C) When frozen
D) When dammed
20) What is the term for sediment deposited by streams?
A) Fluvium
B) Colluvium
C) Alluvium
D) Talus
21) In which part of a stream’s course would one typically find bedrock channels?
A) Headwaters
B) At confluences
C) Mouth
D) In a delta
22) Which of the following is not one of the three basic stream channel morphologies?
A) Straight channel
B) Meandering stream
C) Braided stream
D) Bedrock channel
23) A ________ stream consists of a complex network of converging and diverging channels that
weave around channel bars.
A) Straight channel
B) Meandering stream
C) Braided stream
D) Bedrock channel
24) Which of the following locations is a likely place to find a braided stream?
A) Flowing across a stream delta
B) Flowing across a low gradient landscape
C) Flowing through a karst region
D) Flowing from the terminus of a glacier
25) What is base level?
A) The highest elevation streams can be found
B) The downward limit of erosion
C) The transition from a straight channel stream to a meandering stream
D) The gradient line along the longitudinal profile of the stream
26) What is the ultimate base level?
A) Continental Divide
B) A basalt flow beneath softer sedimentary rocks
C) Sea level
D) The bottom of a waterfall
27) A(n) ________ stream is a stream that is in equilibrium and is neither eroding or depositing
material, but simply transporting it.
A) Graded stream
B) Braded stream
C) Alluvial stream
D) Bedrock stream
28) What is the knickpoint?
A) The location on a meandering stream where water leaves the cutoff and enters the old
meander loop
B) The point in a channel where distributary channels begin to develop
C) The physical evidence of headward erosion in the headwaters of a stream valley
D) The edge of a resistant ledge over which a stream flows, becoming a waterfall
29) ________ are flat areas along streams that are created by the deposition of alluvium and is
subject to periodic inundation.
A) Terraces
B) Floodplains
C) Riffles
D) Bars
30) How many subdeltas have been formed by the Mississippi River in the last 6,000 years?
A) 6
B) 2
C) 5
D) 7
31) What is an antecedent stream?
A) A stream that existed before uplift in a region
B) A stream flowing over a bed displaced by faulting
C) A stream that steals flow from another through headward erosion
D) A stream that eroded its channel into an existing structure
32) What is a flood?
A) When dry weather results in a high discharge
B) When discharge in a river exceeds the river’s capacity
C) When a dam is constructed and forces sedimentation
D) When changes in gradient result in the abandonment of meander loops
16.2 True/False Questions
1) The hydrologic cycle is off-balance because more liquid is brought in via comets and
meteorites each year.
2) When precipitation falls, water may not immediately soak in, run off, or evaporate.
3) Running water is the single most important erosional agent sculpting Earth’s land surface.
4) The Nile River in Africa is a stream.
5) Maximum velocity occurs when the stream is at the bankful stage.
6) When discharge increases, the flow velocity will increase. However, the width and depth of
the stream will decrease because the stream downcutting.
7) As stream velocity slows, the smallest particles get deposited first.
8) Streams carry most of their sediment load in the form of suspended load.
9) Point bars are locations where erosion occurs whereas cutbanks are locations where deposition
occurs.
10) Waterfalls are temporary features in the geologic record.
11) In a series of stream terrace levels, the oldest terrace is the one that is lowest in elevation.
12) In order for a stream to build and maintain a bird’s-foot delta, a stream has to be carrying
more sediment to the delta than is being removed by wave action.
13) Levees are artificial, not natural formations.
16.3 Short Answer Questions
1) Define evapotranspiration.
2) When will the most runoff be generated: at the beginning of a series of storms or at the end?
3) Over oceans, rates of evaporation exceed those of precipitation. In spite of this, sea level does
not drop. Explain why this is the case.
4) Streams generally receive their water from two sources. What are those two sources?
5) What will happen to the water level in the stream if the water table is below the level of the
stream channel?
6) The Crymea River flows through the town of Erehwon. At the east end of town, the elevation
of the river is 654 ft. above sea level. At the west end of town, the elevation is 639 ft. above sea
level. If the town stretches along a five-mile segment of the river, what is the gradient?
7) The Army Corps of Engineers (ACOE) in Erewhon is trying to determine the discharge of the
Crymea River to make sure it is appropriate for barge transportation. Looking at a cross-sectional
diagram that was generated when a bridge was built, they know that the river has a triangular-
shaped streambed. They also know from previous measurements that the river is 1/2 mile wide.
It has been a rainy spring in Erewhon, so the river is currently 20 ft. deep. If the water is
currently flowing at a rate of 5 ft. per second, what is the discharge of the river?
8) After finishing their previous discharge calculations, the ACOE realize they had not been
looking at a cross-sectional diagram of the Crymea River, but of another river. Studying the
correct document this time, they realize that the shape of the river is not a triangle. Instead, it is a
flat-bottomed stream with a relatively consistent depth of 13 ft. Assuming the other variables are
the same, how will the calculated discharge change?
9) What is saltation and why would a particle saltate?
10) What are three methods a stream can use to erode bedrock?
11) If clay particles are smaller than silt particles, why is it harder for moving water to pick up
clay?
12) Which type of channel (bedrock or alluvial) will have meandering streams?
13) In addition to migrating laterally, the meanders in a meandering stream will also migrate
________.
14) What is the difference between a floodplain and a stream terrace?
16.4 Matching Questions
Match the type of sediment load to the correct definition.
A) Fine sediments that are held up by the water and carried throughout the water column
B) Ions in solution that are dispersed throughout the flow
C) Larger sediments that bounce, roll, or slide along the bottom
1) Dissolved Load
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 16.4 – The Work of Running Water
Focus/Concepts: 16.4
Earth Science LO: 4.8 – Weathered and unstable rock materials erode from some parts of Earth’s
surface and are deposited in others.
2) Bed Load
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 16.4 – The Work of Running Water
Focus/Concepts: 16.4
Earth Science LO: 4.8 – Weathered and unstable rock materials erode from some parts of Earth’s
surface and are deposited in others.
3) Suspended Load
Diff: 1
Bloom’s Taxonomy: Knowledge
Global Sci Out: 7
Section: 16.4 – The Work of Running Water
Focus/Concepts: 16.4
Earth Science LO: 4.8 – Weathered and unstable rock materials erode from some parts of Earth’s
surface and are deposited in others.