Earth: An Introduction to Physical Geology, 11e (Tarbuck)
Chapter 17 Groundwater
17.1 Multiple-Choice Questions
1) What percentage of the Earth’s water is in the form of groundwater?
A) 97.2%
B) 94%
C) 0.62%
D) 0.03%
2) What percentage of Earth’s liquid freshwater is in the form of groundwater?
A) 97.2%
B) 94%
C) 0.62%
D) 0.03%
3) Which of the following materials is most readily dissolved by water?
A) Clay minerals
B) Silica
C) Feldspars
D) Calcite
4) Which of the following characteristics is not true or groundwater?
A) Has a constant temperature year-round
B) Rarely contains suspended sediment
C) Short droughts do not affect the supply
D) Rarely contains dissolved solids
5) Which of the following is not a factor that will influence infiltration of groundwater?
A) Acidity of precipitation
B) Steepness of the slope
C) Nature of surface material
D) Intensity of rainfall
6) The ________ is the point in the subsurface where 100% of the pore spaces are filled with
water.
A) Vadose Zone
B) Zone of Saturation
C) Zone of Accumulation
D) Capillary Fringe
7) How will the water table respond if it is a wet spring?
A) Water table will rise
B) Water table will fall
C) Water table will remain the same
8) How will the water table respond when there is a drought?
A) Water table will rise
B) Water table will fall
C) Water table will remain the same
9) What is porosity?
A) Volume of pore space in a material
B) Ability to transmit water
C) When ice crystals deform and slide past each other
D) Dissolution of carbonate rock due to acid
10) What is permeability?
A) Volume of pore space in a material
B) Ability to transmit water
C) When ice crystals deform and slide past each other
D) Dissolution of carbonate rock due to acid
11) Which of the following materials would make the best aquitard?
A) Gravel
B) Sandstone
C) Shale
D) Conglomerate
12) In order for an aquifer to use useful for human consumption, what kind of porosity and
permeability should it have?
A) Low porosity, low permeability
B) High porosity, high permeability
C) Low porosity, high permeability
D) High porosity, low permeability
13) What force pushes groundwater from pore space to pore space when below the water table?
A) Gravity
B) Hydraulic Gradient
C) Hydraulic Conductivity
D) Artesian Pressure
14) Which 19th century scientist developed the equation that determines the discharge of an
aquifer with the following equation:
Q =
A) Charles Lyell
B) Alfred Wegener
C) Louis Agassiz
D) Henri Darcy
15) ________ is a term used to describe how the water table around a well becomes lower as
water is taken from the subsurface.
A) Depression
B) Saturation
C) Perching
D) Drawdown
16) What is the term used to describe the hypothetical line the water in a confined aquifer would
rise to if it weren’t trapped?
A) Potentiometric surface
B) Hydraulic gradient
C) Darcy’s Law
D) Discharge
17) Which of the following regions is famous for its artesian wells?
A) Central Illinois
B) Florida
C) Western South Dakota
D) Coastal Maine
18) What groundwater feature forms where the water table intersects with the Earth’s surface,
creating a natural outflow of groundwater?
A) Fumarole
B) Sinkhole
C) Lake
D) Spring
19) What geologic process is responsible for the geothermal features in Yellowstone National
Park?
A) Radioactive minerals near the surface
B) Volcanic activity
C) Abnormal volumes of rain
D) Normal geothermal gradient
20) What geologic process is responsible for warming the water at Hot Springs National Park?
A) Radioactive minerals near the surface
B) Volcanic activity
C) Abnormal volumes of rain
D) Normal geothermal gradient
21) What mineral substance is makes up most geyser deposits?
A) Travertine
B) Tufa
C) Sinter
D) Obsidian
22) What is the source of the majority of water in geothermal features?
A) Precipitation
B) Water vapor from magma
C) Melting glaciers
D) Subterranean lakes
23) ________ is a term for bacteria that are found in the high temperature, chemical-rich
geothermal features like Octopus Pool at Yellowstone National Park.
A) Cyanobacteria
B) Fungi
C) Stromatolites
D) Extremophiles
24) In which country were geysers were first identified and described?
A) Japan
B) Nepal
C) Iceland
D) United States
25) Which of the following accounts for the largest usage of groundwater in the United States?
A) Domestic and municipal water
B) Agriculture and irrigation
C) Cooling reactors at nuclear power plants
D) Manufacturing and industry
26) Which environmental issue will most commonly affect groundwater aquifers in coastal or
island areas?
A) Subsidence
B) Dissolution
C) Chemical contamination
D) Saltwater contamination
27) Which of the following materials would be the best natural filter, removing contaminants
from groundwater over a long period of time?
A) Fractured granite
B) Slightly clayey sand
C) Conglomerate
D) Mica schist
28) California’s Central Valley is an important agricultural area for U.S. fruit and vegetable
production. Because of the semi-arid climate there, farmers must irrigate their crops. Which
environmental problem do you anticipate would be a problem because of this?
A) Saltwater contamination
B) Fluvial erosion
C) Land subsidence
D) Water acidification
29) What feature is going to develop if a well is withdrawing more groundwater than an aquifer
can naturally replace, resulting in a dimple in the water table?
A) Cone of Depression
B) Subsidence
C) Contamination
D) Saltwater encroachment
30) Which region inspired the term karst topography?
A) The Stone Forest of China
B) Mammoth Cave
C) Republic of Slovenia, in the former Yugoslavia
D) Mining regions in Central Illinois
31) Which acid is responsible for most karst topography?
A) Hydrochloric
B) Nitric
C) Sulfuric
D) Carbonic
32) The general term used to describe cave deposits is ________.
A) Cave pearls
B) Dripstone
C) Bicarbonate
D) Dissolution features
33) While on vacation, you visit a local Imax theater and see a movie about cave diving in the
Yucatan Peninsula. In one of the caves they dive in, which is currently filled with water, you
notice the divers swimming past some stalactites and stalagmites. If the water table is now above
the level of the ceiling of the cave, what does the presence of the cave decorations indicate about
past water table levels?
A) The water table was much higher, with the increased water bringing in extra material to form
the decorations
B) The water table was much lower and the features were formed by water dripping from the
ceiling into an air-filled chamber
C) The water table has always been at that level and they formed through the fracturing of the
ceiling
D) Water table? What water table? All you see is a huge lake!
34) Stalactites start out as hollow tubes called ________.
A) Soda Straws
B) Dripstone
C) Bacon Strips
D) Pipettes
17.2 True/False Questions
1) The majority of groundwater occurs as underground rivers.
2) Groundwater is important as an erosional agent.
3) When precipitation occurs over a forest, only 25% of the water will make it through the
canopy to the forest floor, where other factors may affect how much of that will infiltrate.
4) The water table is the uppermost three feet of the zone of saturation.
5) The water table will undulate with the ground surface. It will be low there the surface is high
and high where the surface is low.
6) Lakes and streams are surface expressions of the water table.
7) Clay’s porosity is high, but its permeability is low, which means that it has a low specific
yield.
8) A typical rate of groundwater flow for many aquifers is approximately 4 cm/day.
9) Groundwater migrates from areas of low pressure to areas of high pressure.
10) Aquitards are made of high-conductivity materials such as clay.
11) Wells are drilled into the subsurface to remove water from the unsaturated zone.
12) A geyser is a type of artesian well.
13) The water in the majority of wells cannot rise above the level of the water table on its own.
14) The majority of Earth’s geysers are found in Iceland.
15) Yellowstone is the tallest geyser in Yellowstone National Park.
16) Freshwater is less dense than saltwater.
17) In semi-arid to arid regions, groundwater is considered to be a nonrenewable resource
because it isn’t replaced at the same rate as it is withdrawn.
18) If a groundwater well pumps enough water to draw down the water table, the drawdown will
increase the slope of the water table, which will increase the velocity of groundwater.
19) Saltwater contamination can be a problem for cities in the continental interior because
significant quantities of seawater were trapped in ancient sedimentary rocks of marine origin.
20) Stalactities grip tightly to the floor of a cave whereas stalagmites hang from the ceiling.
21) Most caverns are created at or near the water table.
22) Caves can only form in limestone.
17.3 Short Answer Questions
1) In what spaces or voids does most groundwater reside?
2) In what ways do humans use groundwater? List at least three ways, not all of which can
involve home or personal use.
3) If gravity pulls infiltrating water downward, what force allows water to be pulled upward at
the capillary fringe?
4) How do scientists map the water table?
5) Undulations of the water table mimic those of the ground surface. What would happen to
those undulations in the water table if all rain were to cease?
6) Circle one: To be a gaining stream, the elevation of the water table must be (higher/lower)
than that of the surface of the stream.
7) ________ is the portion of groundwater that is retained as a film on particle and rock surfaces
and in tiny openings in the subsurface.