Deck 16: A Hidden Reserve: Groundwater

Question 1

Imagine two rocks with the same porosity.Rock A has many small pores connected by thin and winding conduits,while Rock B has fewer but larger pores connected by straight conduits.Which rock is likely to have higher permeability?

A) Rock A
B) Rock B
C) Both rocks will have similar permeability because they have the same porosity.
D) Permeability is not related to the size and shape of pore spaces.

Answer 1

B

Question 2

Igneous rocks typically have few fractures and few if any pore spaces.In other words,unfractured igneous rocks often exhibit _______ porosity and _______ permeability.

A) high; high
B) low; high
C) high; low
D) low; low

Answer 2

D

Question 3

At which point this diagram would water pressure be greatest?

A) at point h₁
B) at the river
C) at point p₁
D) at point p₂

Answer 3

C

Question 4

Material through which water readily flows is termed ________.

A) fluent
B) porous
C) permeable
D) fluid

Question 5

The water table surface mimics the topography in an area because ________.

A) hydraulic head forces it to stay close to the surface
B) the permeability is lowest in hilly areas
C) groundwater cannot penetrate below aquitards
D) groundwater flow rates are so low

Question 6

An impermeable layer of rock or sediment is a(n)________.

A) aquitard
B) confined aquifer
C) unconfined aquifer
D) unsaturated zone

Question 7

An aquifer has ________ porosity and ________ permeability.

A) low; high
B) high; low
C) low; low
D) high; high

Question 8

How can a rock or sediment have high porosity but low permeability?

A) if the pore spaces are filled with sediment
B) if the pore spaces are not well connected to each other
C) if the pore spaces are very large
D) if the pore spaces consist only of straight channel

Question 9

Porosity is best described by which of the following?

A) the hardness of a rock or sediment
B) the chemistry of a fluid in a rock or sediment
C) the amount of open space in a rock or sediment
D) the ability of fluids to pass through a substance (rock or sediment)

Question 10

The dissolution of rock produces ________.

A) primary porosity
B) primary permeability
C) secondary porosity
D) a reduction in primary porosity

Question 11

The pore spaces in rocks,soils,and sediments that are only partially filled with water occur in the

A) zone of recharge
B) saturated zone
C) unsaturated zone
D) water table

Question 12

What is infiltration?

A) the sinking of surface waters and precipitation into the ground
B) the movement of contaminants within an aquifer
C) the reduction of water table due to excessive pumping by wells
D) the expansion of caves and sinkholes in a karst landscape

Question 13

A porous material

A) will be permeable as well.
B) will be impermeable.
C) may be permeable or impermeable.
D) will be neither permeable nor impermeable.

Question 14

The liquid freshwater that occurs within sediments and rock below the Earth's surface is called

A) lakes.
B) rivers and streams.
C) groundwater.
D) atmospheric clouds.

Question 15

Which of the two figures below best shows the location of the water table expected in a dry climate?

A) A
B) B
C) both A and B could be in dry climates
D) water table depth does not depend on climate

Question 16

In which direction would you expect groundwater to be moving in this diagram?

A) from point h₂ to p₁
B) from the river to point p₂
C) from point p₁ to p₂
D) from the pond to the river

Question 17

A layer of gravel,where the sediment grains do not fits together tightly,is likely to exhibit

A) karst landscape
B) high permeability
C) secondary porosity
D) a perched water table

Question 18

In a confined aquifer there is likely to be an aquitard located ______ relative to the aquifer.

A) only above
B) above and below
C) only below
D) upslope

Question 19

Approximately how much of our global freshwater resources are supplied by groundwater?

A) one-quarter
B) one-half
C) two-thirds
D) three-quarters

Question 20

The wide and long fractures in this limestone cause it to have

A) a high water table.
B) high permeability.
C) a high recharge area.
D) low hydraulic head.

Question 21

As a rule,groundwater always flows from areas of ________.

A) greater land elevation to those of lesser land elevation
B) lesser land elevation to those of greater land elevation
C) greater hydraulic head to those of lesser hydraulic head
D) lower hydraulic head to those of greater hydraulic head

Question 22

In the figure below,there are springs located along the surface trace of the fault.Given that the recharge area for these springs is located in the rocks on the left of the figure,what can be said about rock unit A on the right side of the fault?

A) It contains sinkholes.
B) It has high porosity.
C) It has low permeability.
D) It is an aquifer.

Question 23

You have a choice to drill your water well into a shallow unconfined aquifer or a deeper artesian aquifer.Drilling deeper will cost more money; nevertheless,you chose to drill into the artesian aquifer.Why?

A) The artesian aquifer will have a higher permeability.
B) The artesian aquifer will not be subject to overpumping.
C) The artesian aquifer will flow on its own,without a pump.
D) The artesian aquifer will contain more water for your use.

Question 24

In the figure below,where is the discharge area for water infiltrating to the water table at point h₁?

A) at point h₂
B) at the river
C) at the hill
D) at point p₂

Question 25

You are testing the groundwater quality of an aquifer and find that it has high amounts of arsenic.What is the likely source?

A) The arsenic comes from minerals in the aquifer rock that have dissolved.
B) The arsenic comes from the reaction of the water with your testing supplies.
C) The arsenic is being poured into the groundwater to poison the town.
D) All groundwater contains high amounts of arsenic.

Question 26

Where did our word geyser originate?

A) Ancient Rome
B) California
C) Iceland
D) New Zealand

Question 27

A well that does not penetrate below the groundwater table is called a(n)

A) dry well.
B) artesian well.
C) hot spring.
D) unconfined aquifer.

Question 28

A periodic explosive eruption of steam and water from within the ground up through the surface is termed a(n)________.

A) artesian well
B) geyser
C) spring
D) recharge area

Question 29

Hot springs can be formed by the heating of groundwater by magma or by ________.

A) decompression heating
B) infrared heating by the Sun
C) the geothermal gradient
D) heating by the core

Question 30

What is the purpose of the great height of the water tanks used in the water supply systems of many towns?

A) It protects the water supply from contamination.
B) It provides enough water storage to allow a town to continue through a drought.
C) It raises the potentiometric surface of pipes and faucets connected to the water system.
D) It provides a place to store the large pumps needed to supply a whole town's water.

Question 31

For a well to function properly,it must be drilled below the water table and into a(n)_________.

A) aquifer
B) aquitard
C) spring
D) geyser

Question 32

Hard water results from relatively high concentrations of dissolved ________.

A) calcium and magnesium
B) sodium and lithium
C) sodium
D) potassium

Question 33

The elevation of the water table ________.

A) is a constant for a given area so long as the topography remains the same
B) may rise during times of drought and sink during rainy periods
C) may rise during rainy periods and sink during droughts
D) is completely unpredictable

Question 34

In what direction does water flow in the unsaturated zone?

A) horizontally
B) vertically downward
C) it move along the surface of the water table
D) vertically upward

Question 35

What does it mean if the potentiometric surface does NOT reach above the ground surface?

A) The aquifer does not have any recharge into it and thus is dry.
B) There will not be any artesian wells or springs associated with the aquifer.
C) It will not be possible to pull water out of the aquifer from any type of well.
D) The aquifer does not have a high enough permeability to produce water.

Question 36

The volume of groundwater flow over a given time per unit area through a body of rock or sediment is called

A) hydraulic head.
B) confined flow.
C) recharge.
D) discharge.

Question 37

Old Faithful in Yellowstone National Park is an example of a(n)___________.

A) artesian well
B) geyser
C) karst landscape
D) hot spring

Question 38

The lines with arrows in the figure below show several long-distance groundwater flow paths you could expect in a landscape adjacent to a mountain range.Along which flow path is water likely to take the most time between recharge and discharge?

A) path A
B) path B
C) path C
D) All flow paths between the same recharge and discharge zones take the same amount of time.

Question 39

How does the composition of water in hot springs compare to average groundwater?

A) Hot springs contain more dissolved salts and minerals.
B) Hot springs are essentially pure water with no dissolved material.
C) Hot springs very closely resemble nearby groundwater that is not elevated in temperature.
D) Hot springs are more similar to the composition of seawater.

Question 40

Pumping vast quantities of water locally ________.

A) raises the local water table
B) lowers the local water table,forming a cone-shaped depression
C) lowers the local water table,forming a cylindrical depression
D) does not affect the water table

Question 41

On the image below,identify the drainage divide and regions of discharge and recharge,and label the water table.Then draw arrows showing the flow of groundwater.

Question 42

In coastal communities,high rates of fresh groundwater withdrawal can raise the boundary between fresh and underlying saltwater aquifers and contaminate water supplies with salt.This process is called

A) mineralization.
B) saline intrusion.
C) hydraulic head.
D) pore space collapse.

Question 43

What are some ways that a rise in the water table could be damaging or hazardous?

Question 44

Explain how limestone caves are formed,making sure to include the name of the acids involved and how they form.

Question 45

The images below are of two different geological scenarios in which springs could form.Describe the similarities and differences between these two scenarios.

Question 46

Topography dominated by depressions formed by the collapse of caves is termed a ________.

A) valley and ridge province
B) karst landscape
C) horst and graben landscape
D) speleothem formation

Question 47

A(n)________ aquifer is more likely to be contaminated than a(n)________ aquifer.

A) confined; unconfined
B) unconfined; confined
C) artesian; confined
D) artesian; unconfined

Question 48

The commercial distribution of bottled "spring water" has become a major business worldwide,and many people think that this water offers health benefits.Evaluate this belief.How is spring water different from groundwater?

Question 49

Common features in caves include stalactites,which _______ and stalagmites,which ________.

A) grow down from the ceiling; grow up from the floor
B) grow near the mouth of the cave; grow deep in caves where light never penetrates
C) grow up from the floor; grow down from the ceiling
D) grow above the water table; grow below the water table

Question 50

What are porosity and permeability,and how do they affect the rate of groundwater flow?

Question 51

In the image below,label the confined aquifer,the unconfined aquifer,and the aquitard.If you were to drill a well for personal use in this region,in which of these three layers would you put your well? Why?

Question 52

Imagine that some of the wells around a city have begun to show elevated levels of a toxic substance.Without knowing what the toxic substance is,how can you use groundwater characteristics to determine what the source of the chemicals might be?

A) Without knowing what the toxic chemical is,it would be impossible to pinpoint where the source is.
B) Determine if there are any chemical factories in the area and report them to the authorities.
C) Use the gradient in hydraulic head among contaminated wells to estimate the groundwater flow paths
D) Determine which well shows the highest concentration and determine the closest source to that well.

Question 53

Groundwater depletion occurs when

A) geothermal heating turns groundwater into steam.
B) the water table rises when a well pump is turned off.
C) fresh groundwater is contaminated with salty water from the ocean.
D) groundwater is pumped from an aquifer faster than it can be resupplied.

Question 54

Why would a rise in the water table be a potential danger to a homeowner?

A) It costs much more to drill a well when the water table is close to the land surface.
B) Most homes are buoyant,so they may break free of their foundations and float away.
C) If the water table rises above the level of a home's basement,water could seep through the foundation and cause a flood.
D) Household well pumps do not work very well when the water table rises.

Question 55

Label the three zones,on the image below,that water moves through as it percolates into the Earth.Also include where the water table is by marking it with an arrow.

Question 56

List and describe one possible effect of overpumping.

Question 57

The collapse of the land surface into an underground cavern results in a feature called a

A) disappearing stream.
B) sinkhole.
C) cone of depression.
D) contaminant plume.

Question 58

Vesicular basalt has high porosity but very few fractures.Its pores are isolated and not well connected to each other.Would this basalt then make a good aquifer? Why or why not?

Question 59

Land subsidence is likely when ________.

A) groundwater recharge occurs
B) the calcium and magnesium content of groundwater increases
C) the water table raises
D) lowering the water table causes sediment pores to collapse

Question 60

The majority of large cave and karst systems have resulted from ________ etching into ________.

A) carbonic acid; limestone
B) ascorbic acid; dolostone
C) phosphoric acid; shale
D) sea water; rock salt