Deck 13: Running Water

Question 1

Which of the following must result in a lower base level for rivers and streams?

A)Sea level rises; land rises.
B)Sea level falls; land subsides.
C)Sea level falls; land rises.
D)Sea level rises; land subsides.

Answer 1

C

Question 2

A stream begins at an elevation of 200 meters and flows a distance of 400 kilometers to the ocean? What is the average gradient?

A)0.5 km/in
B)2m/km
C)2km/m
D)0.5m/km

Answer 2

D

Question 3

A _ drainage pattern is common in the Appalachian Valley and Ridge Province.

A)polygonal
B)trellis
C)dendritic
D)circular

Answer 3

B

Question 4

Entrenched meanders are evidence for what sequence of geologic events?

A)A sea level rise was followed by stream downcutting.
B)Land uplift was followed by stream downcutting.
C)Stream downcutting was followed by a rise in base level.
D)Lateral cutting by streams was followed by subsidence of the land.

Question 5

Where is erosion concentrated along a meandering stream?

A)at the unconsolidated point bars
B)on the straight channel segments that connect the meander loops
C)on the inner banks of the meander loops
D)on the outer parts of the meander loops or bends

Question 6

The River has the largest discharge of any in the world.

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

Question 7

Which of the following features characterize wide streams and valleys?

A)natural levees; broad floodplains
B)V- shaped valley cross- sections
C)waterfalls; entrenched meanders
D)rapids; channel bed potholes

Question 8

describes the particle transport mode in streams intermediate between suspension and rolling along the bottom.

A)Siltation
B)Impact leaping
C)Saltation
D)Alluviation

Question 9

A natural, meandering, river channel is modified into a more or less straight and smooth, canal- like channel. Which of the following statements is correct?

A)The natural channel had a lower gradient and higher friction than the straight channel.
B)The straight channel has a higher gradient and more friction than the natural channel.
C)The natural channel had a lower gradient and less friction than the modified channel.
D)All of the above statements are true.

Question 10

Which of the following is the only correct response concerning the location and causes of the extraordinarily severe, 1993, flooding on the Mississippi River and tributaries?

A)upper basin; very heavy, sustained rainfall in the late spring and early summer
B)lower basin; very heavy, late summer rains associated with a severe hurricane
C)upper basin; rapid melting of an unusually deep snow pack in early spring
D)lower basin; heavy rains in late spring and early summer

Question 11

What is the drop in water surface elevation divided by the distance the water flows?

A)hydraulic capacity
B)stream gradient
C)hydrologic resistance
D)stream discharge

Question 12

is not part of the hydrologic cycle.

A)Water evaporating from a lake
B)Water moving into creeks and streams following a rainstorm
C)Water infiltrating into the soil and bedrock
D)Calcium carbonate dissolving in soil water and groundwater

Question 13

A _ stream pattern develops on lands underlain by tilted or folded, alternating hard and soft, sedimentary strata.

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

Question 14

A _ stream pattern is developed only on growing mountains like volcanoes or where the land surface is tectonically doming upward.

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

Question 15

At the head of a delta, the major channel splits into smaller channels that follow different paths to the sea. These smaller channels are known as .

A)cotributaries
B)distributaries
C)endotributaries
D)exotributaries

Question 16

Which one of the following statements is TRUE concerning natural levees?

A)They are erosional features left behind when meander cutoff occurs.
B)They are mostly fine sand and silt that build up during floods.
C)They are depositional features formed at times of low discharge.
D)They form the high, steep banks of a downcutting stream.

Question 17

Many larger rivers in the Colorado Plateau region meander in deep, narrow canyons and have no floodplains. How could this happen?

A)As sea level rose, the original, old age streams were rejuvenated.
B)Original, old age streams downcut as the land gradually rose.
C)Original, youthful streams continued to downcut as the land rose.
D)As sea level dropped, the original youthful streams matured into old- age streams.

Question 18

Which one of the following is TRUE concerning a major river system?

A)Channel bed roughness and turbulence generally increase downstream.
B)Upstream tributaries generally have lower gradients than the major river.
C)Discharge decreases below junctions with perennial tributaries.
D)Upstream tributaries generally have higher competencies than the major river.

Question 19

A dam and reservoir are constructed on a graded river. What will happen?

A)deposition upstream from the dam; channel downcutting below
B)deposition upstream and downstream from the dam
C)channel downcutting upstream from the dam; deposition below
D)channel downcutting upstream and downstream from the dam

Question 20

Which one of the following does not apply to stream turbulence and average velocity?

A)channel shape; bed roughness
B)laminar flow; dissolved load
C)stream gradient; channel roughness
D)discharge; stream gradient

Question 21

Which component of the hydrologic cycle describes the recharge of water to the soil and groundwater systems?

Question 22

comprise the suspended loads of most rivers and streams.

A)Silt and clay- sized, detrital grains
B)Sand and gravel that move during floods
C)Dissolved salts
D)Dissolved ions and sand

Question 23

Which one of the following statements correctly describes how stream terraces can form?

A)A temporary base level is eliminated; the stream downcuts upstream from the old temporary base level, and the former floodplain is left well above the present elevation of the stream.
B)Base level rises; the stream downcuts, and the old floodplain is left well above the elevation of the present- day channel.
C)A temporary base level is eliminated; the stream aggrades its channel upstream from the old temporary base level, and the former floodplain is left well above the present elevation of the stream.
D)Base level drops; the stream aggrades its channel, and the former floodplain is left below the present elevation of the stream.

Question 24

in a delta are essentially cross strata inclined toward deeper water.

A)Foreset beds
B)Backset beds
C)Bottomset beds
D)Topset beds

Question 25

In the absence of cutoff, how does a river meander loop behave over time?

A)The gradient is lowered as the loop shortens, and the channel migrates toward the cut or inner bank of the loop.
B)The gradient is lowered as the channel lengthens and migrates toward the cut or outer bank of the loop.
C)The gradient is raised as the loop lengthens, and the channel migrates toward the cut or inner bank of the loop.
D)The gradient is raised as the loop shortens, and the channel migrates away from the cut or outer bank of the loop.

Question 26

generally constitutes the highest percentage of the annual sediment load moved by a stream.

A)Suspended load
B)Dissolved load
C)Saltation load
D)Bed load

Question 27

is defined as the drop in elevation of the stream surface divided by the distance the water flows.

Question 28

are components of the hydrologic cycle that release water vapor directly to the atmosphere.

A)Discharge and transportation
B)Evaporation and transpiration
C)Runoff and infiltration
D)Precipitation and runoff

Question 29

is an abandoned, cutoff, meander loop.

A)A gatorback
B)A builtrail
C)An oxbow
D)A cowhock

Question 30

is the release of water vapor to the atmosphere by plants.

Question 31

describes the total sediment load transported by a stream.

A)Hydro- load factor
B)Capacity
C)Discharge
D)Competence

Question 32

Which one of the following statements is correct?

A)Sea level rises when water is added to the oceans through increased rainfall and increased inflow from rivers.
B)Sea level drops when evaporation rates increase over the oceans and when this extra, atmospheric moisture falls on land as rain.
C)Sea level rises when water is stored in expanding ice sheets and continental glaciers.
D)Sea level drops when water is stored in expanding ice sheets and continental glaciers.

Question 33

is the quantity of water flowing past a certain stream cross section per unit time.

Question 34

The describes the movement of water through Earth's hydrosphere.

A)aquatic cycle
B)precipitation cycle
C)aqualytic cycle
D)hydrologic cycle

Question 35

Which one of the following best describes how urbanization affects small- stream watersheds?

A)Infiltration is reduced; lag time between storms and peak runoff is increased.
B)Infiltration increases slightly; lag time between storms and peak runoff decreases.
C)Infiltration and lag time between storms and peak runoff increase.
D)Infiltration decreases; lag time between storms and peak runoff is shortened.

Question 36

Why is a bird- foot delta like that of the present- day Mississippi below New Orleans likely to change naturally toward one with the shape of an equilateral triangle like the upper- case, Greek letter delta (A)?

A)Present- day distributaries have higher gradients than potential new ones.
B)Potential, new, distributary channels have higher gradients, causing downcutting of the existing channels.
C)Increased sediment loads since the mid- nineteenth century have caused the major distributaries to be filled with sand.
D)Potential, new, major distributary channels have steeper gradients than existing channels.

Question 37

are characteristics of downcutting streams and a youthful stage of valley evolution.

A)Meandering channels and natural levees
B)Wide floodplains
C)U- shaped, cross- valley profiles
D)Rapids and lots of whitewater

Question 38

The lowest elevation limiting stream erosion is called .

Question 39

How does urbanization (paving, etc.)affect runoff and infiltration in a small, previously forested, drainage basin?

A)runoff decreases; infiltration increases
B)both increase
C)infiltration decreases; runoff increases
D)both decrease

Question 40

Which of the following is the correct definition of stream gradient?

A)the water pressure at the bottom of the stream divided by the stream's width
B)the increase in discharge of a stream per unit drop in elevation
C)the distance traveled by water in a channel times a drop in elevation
D)the drop in elevation of a stream divided by the distance the water travels

Question 41

refers to sediments deposited from streams.

Question 42

is the total quantity of sediment carried by a river.

Question 43

A city located on a large river has a history of moderate flooding over its 150- year history. However, the severity and magnitude of flooding has increased dramatically in the past 30 years. Give some possible reasons, both natural and human- induced, as to why such increased flooding might occur. What flood control techniques may be used to reduce flood damage, and how may they contribute to other problems?

Question 44

is the boundary line separating adjacent, stream drainage basins

Question 45

Briefly compare those stream characteristics that decrease in a downstream direction with those that increase downstream. Also, indicate whether or not these changing stream characteristics tend to favor erosion or deposition of sediments.

Question 46

What stream characteristic is measured by the size of the largest particle that a stream can move?

Question 47

is the sediment transport mode in which sand grains alternately bounce up into the water column, sink, and roll or skip along the bottom before bouncing again.

Question 48

What generalizations can you make regarding the geology of a given area by examining stream drainage patterns on a topographic map? Give some examples. Also, are there limitations to such generalizations?