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A) bed load.
B) suspended load.
C) dissolved load.
D) flow load.
48) The largest material that can be carried by a stream is carried as
A) bed load.
B) suspended load.
C) dissolved load.
D) flow load.
49) Bed load is moved by
A) saltation.
B) traction.
C) suspension.
D) saltation, traction, and suspension.
E) both saltation and traction, but not suspension.
50) If the load exceeds a stream's capacity, sediment accumulates in the bed in a process called
A) downcutting.
B) degradation.
C) aggradation.
D) saltation.
51) Excess sediment may result in which of the following channel patterns?
A) V-shaped valleys
B) braided stream
C) meandering stream
D) straight, steep-walled channels
52) Large river systems that have multiple large channels across a vast floodplain are termed
A) anabranching rivers.
B) braided streams.
C) meandering streams.
D) steep-walled channels.
53) Braided streams are not found in
A) areas where the load is higher than the capacity.
B) bedrock-controlled channels.
C) streams subject to new sediment from glaciers or landslides.
D) locations subject to sediment deposition on the river bed.
54) Channels with gradual slopes often develop a sinuous form called a ________ pattern.
A) braided stream
B) anabranching
C) meandering stream
D) straight
55) A meandering stream is one that is
A) completely stable.
B) completely unstable.
C) delicately balanced between equilibrium and chaos.
D) closed in terms of energy and matter input.
56) Maximum velocity in a straight channel is found
A) near the bottom.
B) near the inside of a meander.
C) at the center and near the surface, corresponding with the deepest parts of the stream channel.
D) at the center and near the surface, corresponding with the shallowest parts of the stream
channel.
57) Maximum velocity in a meandering stream is
A) near the bottom.
B) at the inner portion of the meander curve.
C) at the center and near the surface.
D) at the outer portion of the meander curve.
58) The portion of each meandering curve subject to the fastest water velocity undergoes the
greatest erosive action. This action forms a steep
A) meander scar.
B) oxbow.
C) cutback.
D) point bar.
59) The portion of each meandering curve subject to the slowest water velocity undergoes
aggradation. This results in a(n)
A) meander scar.
B) oxbow.
C) cutback.
D) point bar.
60) As they migrate, meandering streams erode their out outside banks, often forming a narrow
neck of land that eventually erodes through and forms a ________ and the stream becomes
________.
A) meander scar; narrower
B) cutoff; straighter
C) cutback; more sinuous
D) point bar; wider
61) A(n) ________ is a meander that becomes isolated from the rest of the river.
A) owbow lake
B) undercut bank
C) point bar
D) cutoff
62) A cutoff on a meandering stream results in the formation of
A) an oxbow lake.
B) a levee.
C) a point bar.
D) a terrace.
E) a braided stream.
63) A(n) ________ is a stream maintain an equilibrium between the processes of erosion and
deposition and, therefore degradation and aggradation.
A) graded stream
B) oxbow
C) anabranching river
D) meandering stream
64) A stream becomes graded when
A) erosion and deposition are in equilibrium.
B) a local base level controls the stream.
C) a river achieves a longitudinal stream profile of a steeper upstream portion.
D) its basin becomes rejuvenated.
65) Which of the following is likely to occur if the gradient of a stream increases? (Assume that
the discharge and sediment load remain unchanged.)
A) The stream will begin to deposit more of its load.
B) The amount of aggradation in the channel will increase.
C) The amount of bed load transport will decrease.
D) The stream will begin to erode its channel and/or its banks.
66) A stream that downcuts at the same rate as tectonic uplift, thereby maintaining its course is
called a(n)
A) meandering stream.
B) anabranching river.
C) antecedent stream.
D) rejuvenated river.
67) Entrenchment of a channel occurs because
A) a decrease in stream gradient occurs.
B) a change in the bed load size-distribution occurs.
C) the river flows from consolidated rock into a region composed of loose sediments.
D) rejuvenation occurs due to uplift.
E) isostatic downwarping of the crust occurs.
68) Which of the following is incorrectly matched?
A) cutbank — outer portion of a stream meander
B) point bar — area of substantial erosion
C) aggradation — sediment accumulation in the stream channel
D) braided stream — maze of interconnected channels
69) Which of the following is correct of the longitudinal profile of most rivers?
A) It always changes at a constant rate from the headwater region to the sea.
B) It is convex in shape.
C) It is concave in shape.
D) It is gentle upstream and steep downstream.
70) Which is typical of a rejuvenated system?
A) entrenched meanders
B) oxbow lakes
C) increased downcutting
D) terraces
E) entrenched meanders, increased downcutting and terraces
71) An interruption in a stream's graded profile of equilibrium is called a
A) gradation.
B) longitudinal interruption.
C) base level.
D) nickpoint.
72) ________ is the general term for unconsolidated clay, silt, sand, gravel, and mineral
fragments deposited by running water.
A) Alluvium
B) Deposition
C) Aggradation
D) Degradation
73) Which of the following is incorrect regarding floodplains?
A) They are formed by recurrent flooding in the area adjacent to the stream.
B) Natural levees on either side of a stream are formed during times when the stream is at flood
stage and overflows the bank.
C) They are generally low-lying areas.
D) They are characterized by rapids and low waterfalls.
74) Which of the following is correct of floodplains?
A) They rarely occur in a fluvial landscape created by an "old" river.
B) They are erosional landforms.
C) They often evolve after a stream has ceased downcutting at a significant rate.
D) They are the areas of a stream where terraces are present.
75) Which of the following is correct of a floodplain?
A) It is an erosional feature located within a depositional feature.
B) Floodplains are not associated with deposition.
C) It is generally filled with layers of alluvium.
D) Despite the name, they are rarely subjected to flooding.
76) Natural levees are created during
A) floods.
B) normal flow conditions.
C) low flow conditions.
D) degradation.
77) The average size of sediment in a natural levee is ________ that found in the surrounding
floodplain.
A) larger than
B) smaller than
C) the same size as
78) As a stream's velocity decreases, which of the following sizes of sediments will be deposited
last?
A) gravel
B) sand
C) silt
D) clay
79) A yazoo tributary stream cannot join with the main river in an area because
A) the yazoo flows in a different valley.
B) a small structural ridge separates the rivers.
C) a natural levee on the main river prevents joining.
D) a man-made flow control structure keeps the rivers separate.
80) The entrenchment of a river into its own floodplain produces
A) backswamps.
B) alluvial terraces.
C) natural levees.
D) river deltas.
81) Which of the following will favor stream terrace formation?
A) a large increase in sediment load
B) tectonic uplift of the headwaters
C) a rise in sea level
D) a decrease in rainfall
82) The primary cause of terrace formation is
A) an increase in channel load.
B) a decrease in flood frequency.
C) an increase in a river's velocity.
D) flow through loose sediment.
83) Cone-shaped deposits of sediment often found at mouth of canyons in arid and semiarid
climates are called
A) deposition.
B) deltas.
C) alluvial fans.
D) clastics.
84) Alluvial fans are formed as flowing water ________ as it leaves a constricted channel.
A) gains velocity
B) changes direction
C) down cuts
D) loses velocity
34
85)
This landform results from when water exists a constricted channel and loses velocity.
A) meander scar
B) delta
C) alluvial terrace
D) alluvial fan
86) When a river reaches a base level, its forward velocity rapidly decelerates as it enters a larger
body of standing water and ________ is formed.
A) an estuary
B) an alluvial terrace
C) a delta
D) a stream terrace
87) Which of the following does not favor delta formation?
35
A) strong ocean currents
B) shallow ocean water along the coast
C) a lack of reservoirs upstream
D) a large sediment load
88) A stream's volume of flow per unit of time is its
A) speed.
B) velocity.
C) discharge.
D) flow rate.
89) As the discharge of a stream increases, which of the following also happens?
A) Stream channels narrow, become shallower, and lose velocity.
B) The rate of flow decreases.
C) Channel width increases but channel depth decreases.
D) Width, depth, and velocity all increase.
90) In most river basins in humid regions, discharge is highest
A) upstream.
B) downstream.
C) midstream.
D) at the headwaters.
91) If a stream originates in a humid region, but subsequently flows through an arid region,
discharge is likely highest
A) upstream.
B) downstream.
C) midstream.
D) at an estuary or confluence with another stream.
92) The downstream portion of a river
A) generally becomes more sluggish.
B) generally is of higher velocity, although it is masked by reduced turbulence.
C) features greater hydraulic action than do upstream portions.
D) has lower discharges than do upstream portions.
93) ________ streams flow year-round, fed by snowmelt, rainfall, groundwater, or a combination
thereof.
A) Perennial
B) Intermittent
C) Ephemeral
D) Permanent
