Deck 16: A Hidden Reserve: Groundwater

Question 1

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

Answer 1

A

Question 2

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

Answer 2

C

Question 3

Unconsolidated sediment typically has greater porosity than the lithified rock that forms from it.

Answer 3

True

Question 4

Primary porosity may be reduced by the ____________.

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

Question 5

Rock or sediment with water-filled pores,wherein upward percolation is blocked by an overlying,impermeable layer,is termed a(n)____________.

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

Question 6

The rate of groundwater flow 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 7

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 8

A layer of rock or sediment with exceptionally low permeability is termed a(n)____________ in hydrogeologic contexts.

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

Question 9

If a material is porous,it ____________.

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

Question 10

Which statement about recharge areas is INCORRECT?

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

Question 11

Permeable 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 12

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

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

Question 13

If a material is highly permeable,it ____________.

A) must be porous
B) cannot be porous
C) must be fractured
D) must either have substantial porosity or be fractured

Question 14

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 15

The majority of Earth's liquid freshwater exists in ____________.

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

Question 16

A body of permeable rock or sediment that possesses a water table is termed a(n)____________.

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

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

Freshwater lakes are always discharge areas.

Question 20

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

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

Question 21

Well-sorted sediments typically have ____________ porosity compared to poorly sorted sediments.

A) greater
B) less
C) approximately the same

Question 22

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

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

Question 23

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 24

If groundwater is clear,it can be assumed that it is drinkable.

Question 25

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 26

An ordinary (water-producing)well will result whenever the base of the well extends below the water table.

Question 27

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

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

Question 28

In groundwater,____________.

A) dissolved ions are rarely, if ever, found
B) calcite (in limestone) is more soluble than quartz (in sandstone)
C) minerals may be dissolved but will never precipitate out of solution
D) precipitation may take place but only if the mineral in question is undersaturated

Question 29

An artesian well is one that ____________.

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

Question 30

Water flowing from hot springs ____________.

A) contains more dissolved minerals than water flowing from cool springs
B) contains fewer dissolved minerals than water flowing 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 volcanism

Question 31

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

Question 32

Bioremediation of contaminated groundwater involves ____________.

A) introducing laboratory-cultured viruses that can dissolve the plume
B) pumping oxygen and 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 33

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 34

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

Question 35

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

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

Question 36

Hard water results from relatively high concentrations of dissolved ____________.

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

Question 37

Extensive pumping of fresh groundwater from a coastal aquifer can 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

Question 38

Dissolution of grains in the burial environment produces ____________.

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

Question 39

Land subsidence is likely whenever ____________.

A) groundwater is used nonrenewably from aquifers composed of rock
B) groundwater is used nonrenewably from aquifers composed of sediment
C) groundwater is used renewably from aquifers composed of rock
D) groundwater is used renewably from aquifers composed of sediment

Question 40

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