Deck 16: A Hidden Reserve: Groundwater

Question 1

Freshwater lakes are always discharge areas.

Answer 1

False

Question 2

Why will the sandstone shown in the figure below probably not be permeable?

A) There isn't enough pore space.
B) The pore spaces are too small for water to flow through.
C) The pore spaces are not connected enough
D) Both a and b are correct.

Answer 2

C

Question 3

In the figure below,the flecked material to the right of the fault would be considered a(n)____________.

A) aquifer
B) aquitard
C) artesian well
D) perched aquifer

Answer 3

B

Question 4

Perched water tables occur ____________.

A) above the regional water table, within permeable rock or sediment
B) above the regional water table, within impermeable rock or sediment
C) below the regional water table, within impermeable rock or sediment
D) below the regional water table, within permeable rock or sediment

Question 5

An aquifer that is isolated from Earth's surface by an aquitard is ____________.

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

Question 6

Unconsolidated sediment typically has greater porosity than lithified rock which it forms.

Question 7

Which list correctly orders the three types of subsurface water from shallowest to deepest?

A) groundwater, soil moisture, vadose zone water
B) soil moisture, groundwater, vadose zone water
C) groundwater, vadose zone water, soil moisture
D) soil moisture, vadose zone water, groundwater

Question 8

In a humid climate,the topography of the water table ____________.

A) is unaffected by local surface topography
B) precisely mimics the topography of the ground surface
C) is a subdued (less steeply sloping) mimic of surface topography
D) is an exaggerated (more steeply sloping) mimic of surface topography

Question 9

Primary porosity may be reduced by ____________.

A) compaction of grains
B) cementation of grains
C) Both a and b are correct.
D) None of the above are correct.

Question 10

Dissolution of rock produces ____________.

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

Question 11

An impermeable layer of rock or sediment is termed a(n)____________ in hydrogeologic contexts.

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

Question 12

Sinkholes are a concern primarily for residents whose dwellings are constructed atop ____________.

A) sandstone
B) shale
C) limestone
D) granite

Question 13

A body of permeable,saturated rock or sediment into which water can percolate directly from the ground surface is termed a(n)____________.

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

Question 14

The majority of liquid freshwater within Earth exists in ____________.

A) lakes
B) rivers and streams
C) pores within rock and sediment
D) atmospheric clouds

Question 15

Rock or sediment between the water table and the land surface represents a(n)____________.

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

Question 16

If a material is porous,it ____________.

A) will be permeable as well
B) will be impermeable
C) may be permeable or impermeable

Question 17

Material through which water readily flows is termed ____________.

A) fluent
B) porous
C) permeable

Question 18

Unless it has recently rained,there is no water within pores in the unsaturated zone.

Question 19

In unfractured rock and sediment,water molecules usually take a ____________.

A) straight path
B) wandering path
C) circular path

Question 20

Groundwater ____________.

A) does not affect the porosity of the rock and sediment through which it flows
B) uniformly increases porosity due to dissolution of grains
C) uniformly decreases porosity due to deposition of minerals into pores
D) may increase or decrease porosity through dissolution or deposition

Question 21

Any place where groundwater naturally flows out of the surface of Earth is termed a ____________.

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

Question 22

The relationship governing the rate of groundwater flux was discovered by ____________.

A) Alfred Wegener
B) Isaac Newton
C) Henri Darcy
D) Charles Richter

Question 23

The elevation of the water table ____________.

A) is a constant for a given area as 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

Question 24

As a rule,groundwater always flows from areas ____________.

A) of greater elevation to those of lesser elevation
B) of greater water pressure to those of lesser water pressure
C) of greater hydraulic head to those of lesser hydraulic head
D) near streams to areas beneath mountain ranges

Question 25

A dry well will always result whenever the base of the well is above the water table.

Question 26

An artesian well is one that ____________.

A) discharges groundwater at ground surface without pumping
B) has its intake sited within the saturated zone of an unconfined aquifer
C) has intake sited within the unsaturated zone of an unconfined aquifer
D) has its recharge area at an elevation below sea level

Question 27

An ordinary (water-producing)well is likely to result when the base of the well extends below the water table.

Question 28

You operate a geothermal power plant here.After several years,the wells that have produced hot water and steam are beginning to run dry.If you want to install injection wells (wells that you can pump water into),so that you could recharge the groundwater circulation system and preserve the flow of hot water to your production well,where would you drill them? (Note: Lines are red (dark grey)at the end with the arrowhead and blue (light grey)nearer the ends without arrowheads.)

A) by the blue arrows
B) by the red arrows
C) in between the blue and red arrows
D) at both the blue and red arrows

Question 29

Which factor listed here would not affect the flow of water at a spring?

A) the concentrations of various ions and man-made pollutants
B) conditions of either drought or heavy rainfall at the recharge area
C) the interconnectedness of fractures or pore spaces leading to the spring
D) a decline in the water table in the direction from which groundwater feeds the spring

Question 30

Water flowing from hot springs ____________.

A) contains more dissolved minerals than water emanating from cool springs
B) contains less dissolved minerals than water emanating from cool springs
C) is never hotter than 40°C, so it is always safe to bathe in
D) only occurs in regions of active volcanic eruption

Question 31

A bedrock that has no intergranular porosity,but that has extensive interconnected fractures,____________.

A) is impermeable
B) is probably permeable
C) has secondary porosity
D) Both b and c are correct.

Question 32

Venice,Italy,has largely subsided beneath sea-level because of ____________.

A) polar ice caps melting due to global warming
B) extensive nearby groundwater mining and sediment compaction
C) tectonic forces related to the gradual, ongoing collision of Africa and Europe
D) None of the above are correct; Venice was built underwater during the Middle Ages.

Question 33

The rate of groundwater flow per unit area through a body of rock or sediment depends ____________.

A) only on the slope of the water table locally
B) only on the porosity of the rock or sediment
C) on the slope of the water table and the porosity of the rock or sediment
D) on the slope of the water table and the permeability of the rock or sediment

Question 34

A periodic explosive eruption of steam and water from within the ground up through the surface is termed a ____________.

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

Question 35

Arsenic can be naturally occurring in groundwater.

Question 36

Which statement about recharge areas is NOT true?

A) Recharge areas typically are elevated with respect to neighboring areas.
B) Recharge areas are regions of relatively high precipitation.
C) Recharge areas are the same as discharge areas.
D) Recharge areas are areas where water infiltrates the sediment from above.

Question 37

A well-sorted sediment will have ____________ porosity than a poorly sorted sediment.

A) greater
B) less
C) approximately the same

Question 38

Neither methane nor hydrogen sulfide are naturally-occurring in well-water.

Question 39

Extensive pumping of fresh groundwater from wells near a seacoast is most likely to induce ____________.

A) saline intrusion; with time the well will start to deliver saline water
B) saline expulsion; with time the freshwater/saline water interface within the aquifer will be pushed downward and seaward
C) mineral deposition of salts within the aquifer

Question 40

You are in charge of putting in water well for a large farm.Unfortunately,there has been a lot of groundwater pollution in the area since it became industrialized almost 200 years ago.Referring to the figure below,how far down should you install the openings of the well in order to have the best chance of getting uncontaminated water?

A) to A
B) to B
C) to C

Question 41

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 42

Land subsidence is likely when ____________.

A) groundwater recharge occurs
B) the Ca and Mg content of groundwater increases
C) the water table changes
D) discharge lowers the water table

Question 43

Most large cave and karst systems have resulted from ____________ dissolving ____________.

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

Question 44

Groundwater mining refers to ____________.

A) acid drainage from mines polluting groundwater
B) legal squabbling over groundwater rights ("It's mine!")
C) pumping out water faster than it can be replenished by recharge
D) prospecting an area to find a suitable spot for a well

Question 45

If the cross-section shown here were typical of the main channel of a long river,would you expect the river to dry up as you followed it downstream?

A) Yes, because the water is contaminated.
B) Not if there were additional tributaries entering it downstream.
C) Yes, because it is in a desert.
D) No.

Question 46

Hard water results from relatively high concentrations of dissolved ____________.

A) calcium and magnesium
B) francium and cesium
C) sodium
D) potassium

Question 47

Most dissolution of bedrock to form caves takes place ____________.

A) above the water table
B) just below the water table
C) greater than 10 m below the water table

Question 48

The well shown in this figure has become "contaminated" with naturally occurring salt water,drawn toward it because too much water was pumped from it for too long.What would be an easy way to restore the aquifer,that is,to push the saline groundwater back toward the ocean?

A) Cover the near-shore sea bottom with heavy plastic and concrete to prevent more seawater from entering the aquifer.
B) Install a line of wells between your "contaminated" well and the coast, and place desalination equipment in each one, to remove salinity from the aquifer.
C) Convert your "contaminated" well into an injection well and begin to pump freshwater into the aquifer through it.
D) Increase the amount of rainfall that occurs just inland from your "contaminated" well.

Question 49

Bioremediation of contaminated groundwater involves ____________.

A) introduction of laboratory-cultured viruses that can dissolve the plume
B) pumping nutrients into a contaminant plume to help local bacteria metabolize the plume
C) pumping out the contaminated groundwater and using it to irrigate genetically modified crops

Question 50

Besides its immense size,what else is unusual about Carlsbad Caverns in southeastern New Mexico?

A) Geologists think the system was produced by sulfuric acid rather than carbonic acid.
B) The caverns are within a deposit of rock salt rather than limestone.
C) The caverns were formed within the span of just a few days in 1937.
D) Although there are conduits to the surface, the caverns do not host a population of bats.

Question 51

You find a huge new cave system and discover it has multiple,extensive levels,each about 500 ft below the one above it.What can you infer about the water table in the region?

A) It used to be higher.
B) It periodically dropped further and further.
C) It lies beneath an aquitard
D) Both a and b are correct.

Question 52

Groundwater ____________.

A) rarely, if ever, contains dissolved ions
B) dissolves calcite and limestone
C) can contain dissolved minerals but can never precipitate minerals out of solution
D) can precipitate minerals but only if the ions that would form the mineral in question are undersaturated in the water

Question 53

Which of the following is not evidence for karst topography?

A) salt beds
B) sinkholes
C) limestones
D) disappearing streams

Question 54

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

A) valley and ridge
B) karst
C) horst and graben