Deck 12: Groundwater

Question 1

Describe the features of a partially filled aquifer layer.

Answer 1

Below ground,some rocks layers can contain water.In the zone of aeration,the pore spaces only contain air;in the zone of saturation,the pore spaces contain water.The water table is the surface that separates the zone of aeration from the underlying zone of saturation.

Question 2

What is a cone of depression,where is it found,and what causes it? Why can large cones of depression be a serious problem?

Answer 2

A cone of depression is where the water table is lower in a cone shape in the area around a well.It is caused by excess groundwater pumping,that is,when discharge from a water well exceeds recharge or the rate of groundwater flow.Large cones of depression are a problem because they can cause shallow wells in the immediate vicinity to go dry.

Question 3

How do caves and caverns form?

Answer 3

Groundwater percolating through the zone of aeration dissolves the carbonate rock and enlarges its fractures and bedding planes.On reaching the water table,the groundwater migrates to the surface.The groundwater continues to dissolve rock in the zone of saturation and forms a system of horizontal passageways.The surface streams erode deeper,the water table drops,and a new set of passageways begin to form.The water abandons the channel ways and leaves a set of caves and caverns.

Question 4

Why does the Leaning Tower of Pisa lean? Is it likely to lean so much it will someday fall over?

Question 5

How are stalactites different from stalagmites? Why do they typically form in pairs and often merge to form a column?

Question 6

What is an artesian system? What three geologic conditions must exist for an artesian system to form?

Question 7

What is the immediate source of the water in groundwater?

Question 8

How can limestone be dissolved by groundwater when it is almost insoluble in pure water? How does this happen?

Question 9

Why are porosity and permeability important to groundwater?

Question 10

How do septic systems work to make sewage safe for use as water?

Question 11

How do stalactites,stalagmites,columns,drip curtains,and travertine terraces form?

Question 12

What are hot springs,and what are the sources of heat?

Question 13

What causes the subsidence that sometimes accompanies groundwater use?

Question 14

What are some possible consequences of modifications to the groundwater system caused by human usage?

Question 15

Describe saltwater incursion.What methods are used to counteract saltwater incursion?

Question 16

How do landfills cause groundwater contamination? What can be done in the construction of a landfill that will make it less likely to contaminate groundwater?

Question 17

Discuss the artesian system that underlies South Dakota and extends to central Texas in the Dakota Sandstone.

Question 18

Describe the flow of water from the ground into the water table and to a stream,lake or swamp.

Question 19

What is karst topography? What are some of the features of karst?

Question 20

What methods are used to counteract saltwater incursion?

Question 21

Briefly explain how some limestone and other carbonate rocks can have high porosity and permeability.

Question 22

How are minor impurities filtered out of groundwater?

Question 23

What happens to the water table in an aquifer if the amount of groundwater discharged naturally or withdrawn at wells is greater than the amount added from natural or artificial sources?

Question 24

Describe dripstone and how it forms.

Question 25

On what factors does permeability depend?

Question 26

Briefly explain why the artesian-pressure surface slopes.

Question 27

What effect do water wells have on an aquifer?

Question 28

What are the most common sources of groundwater contamination?

Question 29

Under what conditions will an artesian well flow freely at the surface?

Question 30

Briefly explain why the groundwater table does not rise fastest in areas of low elevation.

Question 31

What are disappearing streams?

Question 32

In what ways are geysers and undersea hydrothermal vent sites similar?

Question 33

What are the three major uses for groundwater?

Question 34

Where do the pollutants go once they enter the groundwater reservoir?

Question 35

How are sinkholes formed?

Question 36

How can granite and many other dense igneous and metamorphic rocks be groundwater reservoirs?

Question 37

Contrast porosity and permeability.

Question 38

How does water move in the capillary fringe?

Question 39

What are the major problems that exist with,or are related to,groundwater supply?

Question 40

What is one of the beneficial results of movement of water within the ground?

Question 41

Hot springs that intermittently eject hot water and steam with tremendous force are known as ____________________.

Question 42

A place where groundwater flows/seeps out of the ground is a(n)____________________.

Question 43

A stream that just disappears has flowed into a(n)____________________.

Question 44

Rounded depressions common in regions having limestone bedrock are known as ____________________.

Question 45

One common,widespread sedimentary rock that is readily dissolved by groundwater is ____________________.

Question 46

The capacity of a material for transmitting fluids is known as its ____________________.

Question 47

An upward-growing projection of calcite created from water that drips from a cave's ceiling is called a(n)____________________.

Question 48

A very large cave or system of interconnected caves is called a(n)____________________.

Question 49

The boundary between the zone of aeration and the zone of saturation is known as the ____________________.

Question 50

Groundwater under high fluid pressure is called a(n)____________________ system.It is confined by rock bodies called ____________________.

Question 51

A permeable layer that transports water is called a(n)____________________.

Question 52

The water stored in the open spaces within underground rocks and unconsolidated material is called ____________________.

Question 53

The major source of the water stored as groundwater is ____________________.

Question 54

Within the zone of saturation,groundwater flows from the region of ____________________ pressure to the region of ____________________ pressure.

Question 55

The energy produced from Earth's internal heat is ____________________ energy.

Question 56

During times of drought,the water table ____________________.

Question 57

An impermeable layer that prevents the passage of groundwater is a(n)____________________.

Question 58

The percentage of open space within a rock or sediment is known as its ____________________.

Question 59

The addition of water to the zone of saturation is known as ____________________.

Question 60

Groundwater is one reservoir of the ____________________ cycle.

Question 61

States in which there is extensive karst topography include:

A)Ohio,Pennsylvania,Virginia,and West Virginia.
B)Florida,Kentucky,Tennessee,Indiana,and Missouri.
C)Minnesota,Iowa,Nebraska,and Kansas.
D)Wyoming,Arizona,Colorado,and Utah.
E)Michigan,New York,and Ohio.

Question 62

The average rate of groundwater flow is:

A)a few kilometers per day.
B)a few meters per day.
C)a few centimeters per day.
D)a few millimeters per day.
E)imperceptible.

Question 63

Which of the following is most porous?

A)sand
B)soil
C)gravel
D)silt
E)clay

Question 64

The Dakota Sandstone is threatened primarily by:

A)pollution.
B)subsidence.
C)saltwater intrusion.
D)extensive use.
E)lack of recharge.

Question 65

Groundwater erupting from geysers that contain dissolved calcium carbonate will form deposits of:

A)stalactites.
B)stalagmites.
C)travertine.
D)quartz.
E)sulfides.

Question 66

In regions of moderate to high rainfall,the top of a stream is the same as the:

A)top of the zone of aeration.
B)top of the zone of saturation.
C)bottom of the aquifer.
D)bottom of the zone of aeration.
E)top of the water table.

Question 67

An example of a rock/sediment type that could be an effective aquiclude is:

A)quartz sandstone.
B)fractured granite.
C)gravel.
D)shale.
E)graywacke.

Question 68

A poorly sorted porous rock/sediment is as permeable as a well-sorted porous rock/sediment.

Question 69

An example of a rock type that could be a good aquifer is:

A)shale.
B)quartz sandstone.
C)clay.
D)basalt.
E)marble.

Question 70

Rocks such as limestone and granite cannot be groundwater reservoirs.

Question 71

A natural fountain that intermittently ejects hot water and steam into the air is a(n):

A)hot spring.
B)volcano.
C)hydrothermal vent.
D)geyser.
E)aquiclude.

Question 72

The general term for deposits of calcite and/or aragonite within caves is:

A)stalactites.
B)stalagmites.
C)spears.
D)dripstone.
E)calcite-stone.

Question 73

By definition,the porosity of rocks/sediments consists of pore spaces between particles/grains.

Question 74

Conditions needed for the development of karst topography include:

A)humid climate.
B)arid climate.
C)carbonate bedrock at a shallow depth.
D)humid climate AND carbonate bedrock at a shallow depth.
E)humid or arid climate AND carbonate bedrock at a shallow depth.

Question 75

The zone above the water table,in which water is suspended,is the:

A)zone of aeration.
B)zone of saturation.
C)water table.
D)ground water.
E)aquifer zone.

Question 76

Which of the following is most permeable?

A)sand
B)soil
C)gravel
D)silt
E)clay

Question 77

A local aquiclude within a larger aquifer results in a(n):

A)cone of depression.
B)perched water table.
C)artesian aquifer.
D)zone of aeration.
E)zone of saturation.

Question 78

About 22% of all usable water in the United States comes from groundwater.

Question 79

Groundwater will move through any rock/sediment or soil that is porous.

Question 80

Where does groundwater discharge naturally?

A)only in the ocean
B)only in springs
C)only in streams
D)only in aquifers
E)wherever the groundwater table intersects the ground surface