E&S Ch 12 Quiz
Approximately how fast does groundwater move beneath the surface of the Earth?
a few meters per day
Which of the following is a common setting for a spring?
a limestone aquifer that intersects the surface
Which of the following would be most useful in investigating groundwater contamination?
a map showing contours of the water table and of contamination levels
Which event is best represented by the hydrograph shown here?
a summer thunderstorm
What happens to the erosive power of a stream as velocity increases?
Erosion increases.
Each number on this figure refers to a location with groundwater in a subsurface material that is consistent in character across the entire figure. Of these locations, which would likely have the fastest groundwater flow?
1
Of these four lakes, which ones are above the water table?
1 and 4
The gradient of the stream between the two ends on the accompanying figure is
10 meters per kilometer.
Each number on this figure refers to a location with groundwater in a subsurface material that is consistent in character across the entire figure. Of these locations, which one has the water table most clearly above the surface?
2
Each number on this figure refers to a location with groundwater in a subsurface material that is consistent in character across the entire figure. Of these locations, which would likely have the slowest groundwater flow?
2 and 3
In which of these four lakes is the water table above the land surface?
2 and 3
If a river originates 200 meters above sea level and travels 100 kilometers to the ocean, what is the average gradient in meters per kilometer?
2 meters per kilometer
Each number on this figure refers to a location with groundwater in a subsurface material that is consistent in character across the entire figure. Of these locations, which one would have groundwater flowing to the left?
4
Based on the accompanying hydrograph, what was the stream discharge when the data period shown in the graph ended?
4 cubic meters per second
What is a drainage divide?
A ridge or strip of high ground separating one drainage basin from another.
Which of the following cannot be caused by overpumping of ground water?
All of these are possible consequences of overpumping.
Compared with curve 2 on this hydrograph, what is a possible explanation for curve 1?
All of these are possible.
Which of the following can be caused by overpumping of groundwater?
All of these can be caused by overpumping.
What is the nature of the water table?
All of these choices are correct.
What typically happens when tributaries join the main river?
All of these choices are correct.
Which of the following controls the rate of groundwater flow?
All of these choices are correct.
Which of the following is a common setting for a spring?
All of these choices are correct.
Which of the following is the correct relationship between stream velocity and sediment load?
As velocity increases, so does the stream's capacity to carry a larger load.
At which site along this stream would a point bar form?
B
This map shows elevations of the water table beneath an area. Which of the following maps is the correct contour map for the water table elevations shown?
B
At which site along this stream would a cutbank form?
C
Which of the features on this aerial photograph is an oxbow lake?
C
Which of the sites on this cross section would be the most likely place for a spring?
C
In mountain streams that are steep with high stream velocities, which pattern of erosion is the most common?
Channel bed is eroded faster than the channel sides.
This figure shows a new well that will pump out groundwater faster than it can be replaced. What will the water table look like after pumping?
D
Which of these hydrographs shows a flash flood?
D
What is the pattern of discharge shown by this hydrograph?
Discharge quickly increases and gradually decreases.
How did this cone of depression in the groundwater form?
Groundwater is pumped from the well faster than it can flow to replenish what is lost.
How would this stream interact with groundwater?
Groundwater would flow into the stream, adding water.
If a well has a cone of depression associated with it because of overpumping of the groundwater, what is a possible consequence?
Groundwater, which may contain pollutants, will flow toward the cone of depression and cause a polluted well.
According to this graph, which shows water balance for the Ogallala aquifer, which of the following statements are true?
More water is taken out of the aquifer than is gained from recharge.
Where on this cross section would groundwater most likely flow out to the surface?
NOT: 2 and 4 OR 2 only
What is a possible way to decrease permeability?
NOT: All of these choices are correct. OR Fracture a rock.
Which sequence of rocks in the associated figures could result in a confined aquifer? (Low = low permeability and High = high permeability)
NOT: B
Which site along this stream would have the highest velocity for that segment of the stream?
NOT: D
What is the mostly likely setting for this drainage pattern?
NOT: Drainages have followed a series of fractures that branch off of one another.
A stream cannot erode below
NOT: Its Channel
What can you conclude by comparing the left and right hydrographs, each of which depict the same amount of time?
NOT: The left diagram has a higher peak discharge.
What is a reasonable interpretation for the flow event recorded by this hydrograph?
NOT: There were two pulses of runoff because there were two storms.
Entrenched meanders represent
NOT: areas where sea level has risen and waves beveled across the coast.
What is a possible way to increase permeability?
None of these choices are correct.
This figure shows a meandering river. Drag each channel profile to its appropriate place along the river.
PICTURE IS ALL WRONG
What is the main way groundwater accumulates?
Precipitation and surface water infiltrate through the upper layers of soil.
Which of the following accompanies urbanization (replacing farms and open areas with cities)?
Runoff occurs more quickly and produces a higher peak flow.
Which of the following is true about transport of sediment in a stream?
Sand can be transported in a series of bounces along the stream bed.
What are some effects of building a dam?
The reservoir (lake) traps sediment that over time fills up part of the reservoir.
What is the mostly likely setting for this drainage pattern?
The area has folded or faulted rocks with different resistances to erosion.
Which of the following is the main reason that a delta forms when a stream flows into a lake or sea?
The velocity of the stream decreases.
This cross section shows the location of a septic tank with harmful bacteria and 5 wells. Which well is least likely to become contaminated?
Well A
On this graph of discharge versus season for a river in the Rocky Mountains, why is the highest runoff likely to be in the spring?
Winter snow melts in the spring.
Feature A, formed where the Nile River encounters the Mediterranean Sea, is
a delta.
A large body of permeable, saturated material through which groundwater can flow well enough to yield sufficient water to wells and springs is a(n)
aquifer.
Which of the following is most likely to be associated with a confined aquifer?
artesian well
The term for groundwater that is confined and rises in a well because it is under pressure is
artesian.
Why does a plume of contamination spread out (become wider) away from the source of contamination?
because of diffusion of the contamination and mixing of contaminated and uncontaminated water
Each number on this figure refers to a location with groundwater in a subsurface material that is consistent in character across the entire figure. Of these locations, which two sites are on the opposite side of a groundwater divide?
between 4 and 5
Where would be the relatively safest place to build a bridge across the stream in the accompanying figure?
between points 5 and 6
What type of stream is shown in this figure?
braided stream
In a material that holds groundwater, porosity
controls the amount of water that can be stored.
Which of the following is NOT a common site for deposition of sediment?
cutbank
Which way is groundwater flowing in this cone of depression?
downward and toward the well from all directions
This map shows contours of the water table, the location of four factories (labeled A, B, C, and D), and contaminated (x) and uncontaminated wells (-). Which factory contaminated the groundwater?
factory C
The arrows drawn perpendicularly to the contour lines on the contour map shown indicate the direction of the groundwater flow. In this example the groundwater is
flowing down the slope of the water table from higher contours to lower ones.
The force behind a river's flow is
gravity.
Which of the following combinations make for the best groundwater reservoir?
high permeability and high porosity
What units of measure would most likely be represented by letters A-E on the bottom of the accompanying hydrograph?
hours
The slope of a water table is also called the
hydraulic gradient.
Construction of a dam results in
increased erosion by clear water released from the dam.
What happens to water velocity downstream? It generally
increases
Bedrock and sediment in a stream is most susceptible to erosion if it is
located in a turbulent part of the river.
Which of the following typically decreases downstream in a river?
maximum sediment grain size
What type of stream is shown in this figure?
meandering stream
When contamination enters groundwater it typically
moves along with the flowing groundwater down the slope of the water table.
The septic tank in this figure will probably
not contaminate the well.
When contamination enters groundwater, it moves along with the direction of the groundwater. The contamination takes on a particular shape called a
plume.
What is the type of stream transportation by a series of short leaps or bounces off the bottom of the streambed?
saltation
Which of the following materials probably has the highest porosity?
sediment composed only of rounded cobbles that rest directly on one another
The amount of sediment carried by a stream is the
sediment load.
Which particles of sediment are most likely to be transported as suspended load?
small, low density particles
This map shows contours of the water table, the location of four factories (labeled A, B, C, and D), and contaminated (x) and uncontaminated (-) wells. Which way will the contamination flow?
south and southwest, down the contours
This map shows elevations of the water table beneath an area. The water table slopes toward the
south.
This map shows contours of the water table and the location of a factory that contaminated groundwater. Where would you drill wells to intercept the contamination?
southeast of the factory
This map shows contours of the water table and the location of a factory that contaminated groundwater. Which way will the contamination flow?
southeast, down the contours
Which of these septic tanks is most likely to spread contaminated groundwater far away from the septic tank, and why?
the right septic tank because it is in limestone with caverns
The size of clasts that a stream can carry is primarily controlled by
the velocity and turbulence of the current.
This cross section shows the location of 5 wells and the water table? Which well is most likely to be an artesian well?
well E