Deck 16: Groundwater

Question 1

The zone of aeration ________.

A)lies above the water table
B)has pore spaces which are filled with water
C)is a well-oxygenated, shallow aquifer
D)lies below the capillary fringe

Answer 1

A

Question 2

After ice sheets and glaciers, ________ contains the next highest percentage of Earth's freshwater that is readily accessible to humans.

A)groundwater
B)the atmosphere
C)lakes and rivers
D)Dasani/Coca-cola Ltd.

Answer 2

A

Question 3

Which statement concerning the water table is false?

A)In humid regions, it is generally higher than lake or stream level.
B)Its elevation is constant and does not fluctuate seasonally.
C)Its shape is a subdued replica of the overlying surface topography.
D)Wetlands (swamps)occur where the water table is at the surface.

Answer 3

B

Question 4

Under most conditions, groundwater moves ________.

A)very quickly as it flows predominantly in open cavernous underground rivers
B)only between rainstorms by drainage
C)very little as most of it is stagnant and all at a single level
D)at slow but variable rates generally less than a few metres per day

Question 5

What proportion of the world's water for industrial use (cooling, solvation, transport, manufacturing etc.)is supplied by groundwater aquifers?

A)25%
B)40%
C)50%
D)87%

Question 6

In general, how do we know where the water table is located?

A)It is always at the base of the soil zone; just measure the soil thickness.
B)By drilling wells, measuring the water levels, and contouring those elevations.
C)Look at the regional streams and measure their depths; that's where the water table is.
D)Just look at a regional map; it is the same elevation everywhere.

Question 7

Where does the majority of fresh groundwater reside?

A)as large stationary bodies in enormous underground caverns
B)flowing in large underground rivers
C)in pores within soils and sediments or in fractures in rocks
D)as superheated steam in vast hotspring and geyser fields

Question 8

A water table is the ________.

A)boundary between the zone of saturation above and partly saturated zone below
B)bottom boundary surface of the zone of saturation above an aquitard
C)boundary between the zone of aeration above and zone of saturation below
D)boundary between the zones of aeration and superposition

Question 9

________ account for the largest usage of groundwater in North America.

A)Water for livestock and poultry
B)Domestic and municipal supplies
C)Industrial uses
D)Agriculture and irrigation

Question 10

Which reservoir of the hydrosphere would you describe as containing the largest fraction of Earth's liquid freshwater?

A)groundwater
B)glaciers and ice sheets
C)lakes and reservoirs
D)soil moisture

Question 11

How do we know which direction ground water will flow?

A)Dye or chemical tracer tests are required, often requiring multiple wells and months.
B)It flows perpendicular to the water table contours, in a downhill direction.
C)It is generally the same as the prevailing wind direction.
D)It is parallel to local stream flow, just slower.

Question 12

What proportion of the world's drinking water is supplied by groundwater aquifers?

A)25%
B)40%
C)50%
D)87%

Question 13

What proportion of the world's water for agriculture (irrigation, greenhouses, golf courses)is supplied by groundwater aquifers?

A)25%
B)40%
C)50%
D)87%

Question 14

Which reservoir of the hydrosphere would you describe as containing only a small fraction of Earth's freshwater that is well mixed and exchanged continually?

A)the atmosphere
B)lakes and reservoirs
C)groundwater
D)soil moisture

Question 15

________ is the volume of voids or open space in a rock or unconsolidated material.

A)Permeability
B)Porosity
C)Saturation index
D)Capillarity

Question 16

Groundwater is tightly held by surface tension to mineral grains or other soil particles in the ________ and actually "wicks up" significant distances above the regional water table.

A)capillary fringe
B)gitchee gumee
C)aquiclude
D)zone of saturation

Question 17

What percentage of the Earth's water is in the form of groundwater?

A)97.2%
B)94%
C)0)6%
D)0)03%

Question 18

The water table is ________.

A)a boundary between unsaturated bedrock and an underground river
B)a flat underground layer of partly saturated rock
C)a boundary between unsaturated bedrock below and saturated bedrock above
D)a boundary between saturated soil/rock below and unsaturated soil/rock above

Question 19

Where does the majority of groundwater originate?

A)by infiltration from precipitation that falls on the land
B)by primordial outgassing from magmatic intrusions
C)it was deposited along with the sediments that contain it
D)released from minerals undergoing diagenetic and metamorphic dehydration reactions

Question 20

What is the belt of soil moisture?

A)a viable farming region across southern Alberta and Saskatchewan without rain
B)the layer in the ground with the largest roots, just beneath the zone of saturation
C)at shallow depth, a surface film of water retained on soil, sediment, or organic particles
D)where permafrost has melted leaving completely saturated soils

Question 21

From the typical hydrologic properties of materials, which would make the best aquifer considering just the water delivery, not its turbidity or chemistry?

A)basalt, gravel, limestone
B)basalt, granite, sandstone
C)clay, sand, soil
D)granite, limestone, sandstone

Question 22

Which would have the highest porosity?

A)angular gravel of variable sizes
B)a mixture of well rounded sand and gravel particles
C)a uniform sized, well rounded sand
D)unfractured crystalline limestone

Question 23

The fastest groundwater flows would be expected for an aquifer with ________.

A)high porosity and many small pores
B)high gradients (hydraulic head)and high permeability
C)low gradients and low permeability with a few very large pores
D)high specific retention and low permeability

Question 24

Of the choices listed on flow characteristics alone, if the following aquifers became contaminated, which would remain contaminated for the longest time?

A)clay
B)gravel
C)limestone
D)sand

Question 25

Of the choices listed below, which would make the best aquifer for water content and delivery?

A)sand
B)clay
C)basalt
D)granite

Question 26

________ is a measure of the connectedness of pore spaces, which controls the ease (or difficulty)of groundwater transmission through a porous material.

A)Portability
B)Potability
C)Permeosity
D)Permeability

Question 27

In a uniformly porous and permeable material, groundwater tends to flow along curved paths ________.

A)as a compromise between the downwards pull of gravity and movement towards areas of lower pressure
B)because this is the shape of the overlying land
C)because this is the shortest distance between recharge and discharge
D)because this is the shape of most sedimentary bodies

Question 28

The direct energy causing groundwater flow from one place to the other is ________.

A)surface tension and capillary forces between water molecules and mineral surfaces
B)gravity due to the weight of water and elevation differences
C)precipitation differences between localities (groundwater flows towards drier areas)
D)solar power driving wind and evapotranspiration

Question 29

________ are characteristics found in all good aquifers.

A)High porosity and high permeability
B)Low permeability and high potability
C)High potability and high portability
D)Low porosity and low permeability

Question 30

What force pushes groundwater from pore to pore below the water table?

A)integrated saturation impulse
B)surface tension
C)hydraulic gradient
D)permeability steepness

Question 31

Which of the following is not a general characteristic of groundwater?

A)constant temperature year round
B)rarely contains dissolved constituents
C)rarely contains suspended sediment
D)supply is independent of short droughts

Question 32

Of the choices listed below, which would make the best aquitard?

A)clay
B)basalt
C)granite
D)sand

Question 33

Most hot springs that are just a little warmer than mean annual temperature (6°-9°C)acquire their heat ________.

A)because most of the recharge from rainfall is in the warmer summer months
B)because most of the groundwater is millions of years old from when the Earth's climate was warmer
C)by deep circulation through progressively warmer rocks at depth (~2°C per 100 metres)
D)because there are young intrusions everywhere at depth, always warming up the crust

Question 34

The porosity of typical unconsolidated sediments and sedimentary rocks is ________.

A)10-50%
B)<0.1%
C)1-5%
D)6-9%

Question 35

For unconfined aquifers, what hydrologic factor is approximated by the slope of the water table?

A)hydraulic gradient
B)hydraulic competency
C)porosity head
D)affluent decline

Question 36

Henry Darcy was ________.

A)an engineer for the Hershey Co.who studied the flow of molten chocolate through beds of crushed peanuts (and for whom the Oh Henry candy bar was named)
B)a hydrogeologist who built caissons on the floor of the Fraser River to provide the first filtered water for the city of Richmond, BC
C)a French engineer who studied the flow of water in pipes and filter beds to provide a municipal water supply for Dijon, France
D)an Oxford educated English aristocrat who studied water flow while designing canals in the Midlands for Charles II

Question 37

A perched water table develops when ________.

A)an aquifer below the regional water table is underlain by a horizontal aquitard
B)an aquifer above the regional water table is overlain by a horizontal aquitard
C)a horizontal aquitard above the regional water table lies below an aquifer
D)an aquitard below the regional water table lies above a horizontal aquifer

Question 38

In Darcy's Law for flow velocity written as: V = (K/n)? (h/l), what does h/l stand for?

A)capacity
B)hydraulic gradient
C)permeability
D)porosity

Question 39

An aquifer is ________.

A)a saturated, porous, and permeable layer or stratum that has high water flow
B)a layer or stratum in which groundwater flows downward to the water table
C)an unsaturated bed or stratum below a spring
D)the best place to dispose of soluble toxic waste

Question 40

In Darcy's Law for flow velocity written as: V = (K/n)? (h/l), what does K stand for?

A)capacity
B)hydraulic gradient
C)permeability
D)porosity

Question 41

Where are the most famous geyser in the world?

A)Banff Hot Springs in the Canadian Rockies
B)Yellowstone National Park, U.S.
C)Iceland's Groundwater Preserve
D)Ottawa's famous bombastic effluent

Question 42

Other than increased pressure, geysers and hot springs tend to get superheated because of dissolved mineral matter which builds deposits of ________ as some of the water boils away leaving supersaturated brines.

A)corundum and feldspar
B)calcareous tufa (travertine)and siliceous sinter (geyserite)
C)halite and gypsum
D)sponge reefs

Question 43

________ would be the best medium to naturally remove sewage pollutants.

A)Fractured granite
B)Well-sorted, coarse gravel
C)Slightly clayey sand
D)Limestone with solution channels and caverns

Question 44

Which one of the following concerning artesian wells is false?

A)The well penetrates an aquifer overlain by an aquitard.
B)The well penetrates an aquifer underlain by an impermeable bed.
C)The aquifer is generally inclined, and it is saturated to an elevation above the point where the well penetrates the aquifer.
D)When the well penetrates the aquifer, the water rises to the bottom of the aquitard above the aquifer.

Question 45

Which of the following geologic materials would have the highest groundwater velocities and be least effective in removing unwanted pollutants from the water?

A)a sandy loam soil with high organic carbon content
B)limestone with numerous solution channels and fractures widened by dissolution
C)lakebeds consisting of unconsolidated very fine-grained sand and silt
D)sandstone; well-cemented with a few, widely spaced vertical fractures

Question 46

Which would be the most prone to surface contamination from runoff and infiltration?

A)an aquifer with a thick, overlying, unsaturated vadose zone
B)deep confined aquifers directly below contaminated sites
C)shallow aquifers with thin soils or unconsolidated coarse overburden
D)wells a few hundred metres uphill from septic systems in rugged mountainous terrain

Question 47

Geysers periodically boil and erupt because ________.

A)new groundwater flows in to replace that lost in the prior eruption, this takes time
B)great pressures from deep water-filled chambers prevent water from boiling until higher temperatures are reached; eventually enough heat is supplied by the hot (volcanic)rocks to expand the water and let it boil anyway
C)each injection of hot magma at depth triggers another episode of boiling in groundwater
D)the god Vulcan is at work at his subterranean forge

Question 48

The mechanical removal or diminution of unwanted substances such as bacteria, viruses, or mineral turbidity from groundwater is termed ________.

A)aqua-cleansing
B)filtration
C)derriereation
D)dolomitization

Question 49

Which of the following best describes how geysers erupt?

A)Water suddenly boils in disconnected voids and cracks above the water table, causing the aquifer to explosively fragment.
B)All of the water in the geyser chamber slowly heats until it reaches the boiling point, whereupon it starts erupting until it boils dry.
C)Water below the water table slowly boils causing a plume of condensed water vapour in a vertical crack or natural conduit to rise above the vent.
D)Expansion from heating forces some warm water out the top of the geyser system; with this reduction in pressure, superheated water in a saturated, natural conduit suddenly boils, sending a plume of steam and hot water into the air above the vent.

Question 50

Suppose a well has become contaminated by harmful bacteria such as E.coli.How can this be removed from an aquifer by natural subsurface processes?

A)asymptotic expansion
B)dissolution, diagenesis, and fossilization
C)mechanical filtration, chemical oxidation, or assimilation by other organisms
D)overpumping for a few days until the well tests clean

Question 51

Excessive groundwater withdrawals can cause ________.

A)uplift through expansion of the dewatered aquifer
B)the water table to decline in elevation and land to subside
C)porosity in the aquifer to increase as the water is removed
D)the cone of depression to invert

Question 52

When water is quickly produced from a well, locally the water table and aquifer experience ________.

A)artesian flow
B)artificial insemination
C)decreased flow velocity towards the well
D)drawdown

Question 53

The travertine hot spring deposits at Rabbitkettle Hotsprings, Northwest Territories, are better developed than most.What rock probably lies deeper beneath the hot springs to account for all the travertine deposits?

A)shale
B)rhyolite
C)limestone
D)quartzite

Question 54

Which of the following describes the configuration of an unconfined water table around a pumping well?

A)a bad impression
B)cone of depression
C)depression withdrawal
D)inverted cone head

Question 55

Which of the following statements is false for an area subsiding because of excessive pumping of groundwater?

A)Dewatered aquifer material compacts.
B)Effluent streams may dry up.
C)Water table is substantially lowered.
D)The aquifer is consolidated bedrock.

Question 56

An artesian well is one in which ________.

A)the water is warm, fairly saline, and recharged by a stream
B)water has enough head to rise above the top of the aquifer without any pumping
C)the well is horizontal and the water table is perched
D)pressurized groundwater rises from a deep, unsaturated aquifer

Question 57

How are travertine or silica deposits formed from boiling geysers and related hydrothermal systems?

A)Boiling off steam forces the remaining hot solution to be saturated or supersaturated as the same mineral content is now concentrated in less water and it precipitates.
B)More gases enter the system once boiling starts forcing precipitation.
C)As pressures increase less mineral matter is soluble.
D)By introduction of cold fresh recharge water which quenches the system.

Question 58

What is the relationship between drawdown and the cone of depression associated with a pumping well?

A)The drawdown is the diameter of the cone of depression measured at the elevation of the original water table.
B)The drawdown is the percentage of available water in the aquifer that has already been used.
C)Drawdown is the distance between the original water table and the water level in the well.
D)Drawdown is dealing from the bottom of the deck in a crooked poker game.

Question 59

Which one of the following statements is true for an artesian aquifer?

A)The water table in the recharge area is at a higher elevation than the top of the aquifer in the subsurface.
B)Upward flow from a permeable aquitard is prevented by a confining aquifer.
C)The pressure at any point in the aquifer is considerably less than the weight of the water column between the point and the top of the aquifer.
D)In deep, stream-cut valleys, many springs are fed from artesian aquifers.

Question 60

An artesian well is one in which ________.

A)the water is warm, fairly saline, and recharged by an affluent stream
B)pressurized groundwater rises from a deep, unsaturated aquifer
C)water rises above the top of the aquifer without any pumping
D)the well is horizontal and the water table is perched

Question 61

________ are specific features of karst topography.

A)Streams flowing into depressions and continuing underground
B)Perched water table springs on hillsides
C)Numerous artesian wells in a given area
D)Perennial streams fed by large springs

Question 62

The water table is the boundary between the zone of aeration, where infiltration occurs, and the zone of saturation where the primary groundwater storage and flow occur.

Question 63

In Jules Verne's classic tale "Journey to the Centre of the Earth", how did the explorers return to the surface?

A)by riding up in a geyser
B)by climbing up a volcano's vent
C)by riding on the back of a pterodactyl
D)by riding up an artesian well

Question 64

Which common, rock-forming mineral or mineral group is most readily dissolved by groundwater?

A)calcite
B)quartz
C)feldspars
D)clay minerals

Question 65

What geo-environmental condition did not contribute to the May 2000 Walkerton tragedy?

A)a shallow overburden with little filtration capacity
B)a fast delivery fractured bedrock aquifer
C)a nearby unsealed test well
D)a buried artesian aquifer

Question 66

Compared to surface waters there are no negative environmental effects from using groundwater and groundwater cannot in fact be over-used.

Question 67

Which of the following can logically be concluded by speleothems/dripstone hanging from a cave roof?

A)The cave roof was below the water table when the speleothems formed.
B)The cave floor was above the water table, and the roof was below the water table when the speleothems formed.
C)The cave roof was above the water table when the speleothems formed.
D)The cave roof was below the water table sometime after the speleothems had formed.

Question 68

Groundwater is not susceptible to any lasting or persistent pollution because it is turned over and replaced so quickly.

Question 69

Which one of the following logically explains why parts of some cavern systems are aerated?

A)The caves formed and later the water table rose.
B)A nearby, downcutting stream lowered the water table after the caves had formed.
C)Streams formerly flowing on the surface were diverted into the groundwater system through sinkholes.
D)The main water table is perched above the cavern roofs, allowing air to enter.

Question 70

Which one of the following is not a speleothem?

A)geyserite
B)dripstone
C)stalactite
D)stalagmite

Question 71

The term karst topography was first used in ________.

A)the Republic of Slovenia
B)eastern Canada in areas of fractured igneous and metamorphic rocks
C)India near the southern foothills of the Himalayan Mountains
D)Australia for the extremely dry interior area near Alice Springs

Question 72

Sinkholes can form ________.

A)in any calcium bearing bedrock
B)in humid regions underlain by carbonates, salts, or gypsum
C)only in limestones
D)only in high elevation areas with sufficient gradient to carry away dissolved materials

Question 73

Which one of the following concerning stalactites and stalagmites is false?

A)Stalactites are deposited from water dripping from the ceiling of an aerated cavern.
B)Both are composed of calcium carbonate.
C)Both are forms of dripstone; stalactites hang from the ceiling, stalagmites grow upward from the cavern floor.
D)Stalagmites form on the floors of caves below the water table.

Question 74

Ground water aquifers can be seen directly in natural caverns and mines.

Question 75

Groundwater accounts for vastly more of the world's total fresh water supplies than lakes and streams and it is the largest reservoir of fresh water that is readily available to humans.

Question 76

Given the right kind of bedrock, cave formation occurs most readily ________.

A)beneath the ocean
B)in tropical areas with high rainfall and abundant vegetation
C)in arid and semi-arid regions with strongly alkaline surface waters
D)in temperate to high latitude settings where seasonal freeze-thaw fractures the bedrock

Question 77

The longest known cave system in the world is ________ with more than 540 kilometres of passages.

A)Castleguard Cave, Alberta
B)Carlsbad Caverns, New Mexico
C)Hayes Cave, Nova Scotia
D)Mammoth Cave, Kentucky

Question 78

An area exhibiting tower karst features would likely have ________.

A)cave formations stacked up throughout a series of different limestone beds
B)caves with open bullet shaped rooms reaching up several stories
C)intricate three dimensional lacework of interlocking soda straws reaching up from the cave floor
D)isolated steep sided hills that are riddled with cave passages

Question 79

A ________ is the icicle-like speleothem that grows down from the roof of a cavern.

A)dingleberry
B)stalactite
C)stalagmite
D)slagmite

Question 80

Considering their relative density and solubility in water, how would hazardous substances behave that accidentally entered a groundwater system?

A)Gasoline and kerosene would float on the water table; ethyl alcohol would dissolve and disperse in the groundwater.
B)Gasoline and kerosene would float on the water table, but most pesticides break down chemically when they reach the water table.
C)Sulphuric and nitric acids would sink to the bottom of the aquifer; kerosene would accumulate as a layer just below the water table.
D)E-coli bacteria may build up in groundwater but can be diluted or rinsed away with sufficient input of natural surface waters such as farm runoff.