Earth Science, 10e

Edward J. Tarbuck & Frederick K. Lutgens

GroundwaterChapter 3 (page 94)

Earth Science, 6e Stan Hatfield and Ken Pinzke

Southwestern Illinois College

Sources of Earth’s water

Distribution of fresh water in the hydrosphere

Water, a renewable resource

Illustrates the circulation of Earth's water supply

Processes involved in the cycle• Precipitation• Evaporation• Infiltration• Runoff• Transpiration

The hydrologic cycle

Groundwater…

Is the largest freshwater reservoir for humans. (90% of our water usage)

Plays important geological roles• As an erosional agent, dissolving by

groundwater produces • Sinkholes

• Caverns

• An equalizer of stream flow

Features associated with subsurface water

Groundwater characteristics

Aquifer (closed/open aquifer)Aquitard or aquicludeZone of saturationZone of aerationZone of recharge/Zone of discharge Water table

Water beneath the surface (groundwater)

PorosityPercentage of pore spaces

Determines how much groundwater can be stored Permeability

Ability to transmit water through connected pore spaces

Springs

Are where ground surface and water table meet:• Springs

• Hot springs

• Water is 6-9ºC warmer than the mean air temperature of the locality

• Heated by cooling of igneous rock

• Geysers

• Intermittent hot springs

• Water turns to steam and erupts

Hot Springs

Old Faithful geyser in Yellowstone National Park

Geysers formation

Water beneath the surface (groundwater)

Features associated with groundwater• Wells

• Pumping can cause a drawdown (lowering) of the water table

• Pumping can form a cone of depression in the water table

• Artesian wells• Water in the well rises higher than the initial

groundwater level

Formation of a cone of depression in the water table

Artesian Well

Pressure Surface

An artesian well resulting from an inclined aquifer

Treat groundwater as a nonrenewable resource

Environmental problems associated with groundwater:

• Pollution (Farming, industrial, etc…)

• Land subsidence caused by its withdrawal

• Salt water contamination

Salt water contamination

Water beneath the surface (groundwater)

Geologic work of groundwater • Groundwater is often mildly acidic

• Contains weak carbonic acid

• Dissolves calcite in limestone

• Caverns • Formed by dissolving rock beneath Earth's surface

• Formed in the zone of saturation

Water beneath the surface (groundwater)

Geologic work of groundwater • Caverns

• Features found within caverns

• Form in the zone of aeration • Composed of dripstone

• Calcite deposited as dripping water evaporates • Common features include stalactites (hanging

from the ceiling) and stalagmites (growing upward from the floor)

Dripstone formations in Carlsbad Caverns National Park

Water beneath the surface (groundwater)

Geologic work of groundwater • Karst topography

• Formed by dissolving rock at, or near, Earth's surface

• Common features

• Sinkholes – surface depressions

• Sinkholes form by dissolving bedrock and cavern collapse

• Caves and caverns

• Area lacks good surface drainage

Development of karst topography

Infrared image of karst topography in central Florida

End of Chapter 3

GROUNDWATER

No Talking Please

1 - PERMEABILITY IS:

a) ABILITY TO STORE GROUNDWATER

b) ABILITY TO STOP GROUNDWATER

c) ABILITY TO TRANSMIT GROUNDWATER

d) NONE OF THE ABOVE

2 - WHICH ONE OF THESE IS A MAJOR POLLUTANT IN OUR

NORTH FLORIDA GROUNDWATER?

a) PHOSPHATES

b) SULFATES

c) NITRATES

d) CARBONATES

3 - WHICH FORCE PUSHES THE GROUNDWATER

THROUGH THE ROCK?

a) THE PRESSURE SURFACE

b) THE DARCY COEFFICIENT

c) THE HYDRAULIC GRADIENT

d) THE SURFACE TENSION

4 - WHICH ONE (S) OF THESE IS (ARE) PART OF KARST

TOPOGRAPHY?

a) SINKHOLES

b) CAVES AND CAVERNS

c) SINKING CREEKS

d) ALL OF THESE

5 - AN AQUIFER IS

a) IMPERMEABLE ROCK ABOVE THE GROUNDWATER

b) POROUS AND PERMEABLE ROCK THAT CONTAINS THE GROUNDWATER

c) SAME AS AQUITARD

d) NONE OF THESE

6 - THE WATER TABLE IS:

a) TOP OF THE AQUIFER

b) TOP OF THE ZONE OF SATURATION

c) TOP OF THE ZONE OF AERATION

d) NONE OF THE ABOVE

7 - WHICH ZONE CONTAINS THE

GROUNDWATER?

a) THE ZONE OF AERATION

b) THE CONE OF DEPRESSION

c) THE PRESSURE SURFACE

d) THE ZONE OF SATURATION

8 - THE LOWERING OF THE WATER TABLE DUE TO

HEAVY PUMPING IS:

a) ZONE OF DEPRESSION

b) ZONE OF SATURATION

c) CONE OF DEPRESSION

d) CONE OF SATURATION

9 - WHICH ROCK IS AN AQUITARD?

a) SANDSTONE

b) LIMESTONE

c) CLAY

d) NONE OF THESE

10 - THE FLORIDIAN AQUIFER IS MADE OF

WHAT ROCK?

a) CLAYSTONE

b) SANDSTONE

c) LIMESTONE

d) MILESTONE

11 - AN ARTESIAN WELL EXISTS WHEN:

a) IT LIES ABOVE THE PRESSURE SURFACE

b) IT LIES BELOW THE PRESSURE SURFACE

c) THE PRESSURE SURFACE IS ABSENT

d) NONE OF THESE

12 - HOW MUCH OF THE OCEAN WATERS ARE IN THE

HYDROSPHERE?

a) 87%

b) 70%

c) 90%

d) 97%

13 - HOW MUCH GROUNDWATER DO WE USE IN

FLORIDA?

a) 80%

b) 70%

c) 90%

d) 97%

14 - A ROCK ABILITY TO STORE WATER IS:

a) PERMEABILITY

b) SATURATION

c) POROSITY

d) AERATION

15 – Which one of these is not source of nitrates pollution in FL?

a. Farming

b. Animal waste

c. Septic Tank

d. Fossil fuel burning

16 - WHAT MAKES WATER FLOW?

a. 1. DISCHARGE

b. 2. RECHARGE

c. HYDRAULIC GRADIENT

d. DARCY’S FORCE

17 – In Florida sinkholes are pathways to the groundwater

a. True

b. False

18 – Fine particles that float on a stream surface are called

a. Bed load

b. Suspended load

c. Floating load

19 – Between stalagmites and stalagtites which ones hang from the

ceiling?

a. Stalagtites

b. Stalagmites

20 - It is possible to check areas prone to sinkhole from satellite

imaging using

a. Laser beam

b. Infrasound

c. Ultrasound

d. Infrared

21. Area where most of the runoff infiltrates the ground is

called

a. Zone of saturation

b. Zone of discharge

c. Zone of recharge

d. Cone of depression

22. Every time we develop a new area we are doing what?

a. Increase the demand for water resources

b. Reduce the amount of water getting into the ground

c. Reduce the recharge zone

d. Increase the risk for water pollution

e. All of the above

26. Well water or city water, they all are originating from the

same aquifer

a. True

b. False

c. Who cares!

23. How much groundwater is there in the hydrosphere?

a. 97%

b. 3%

c. < 1%

d. None of these

24. There are drugs in the groundwater you are drinking

a. True

b.False

c. Great!

d.Who cares!

25. What is safe to drink?

a. City water

b. Well water

c. Bottled water

d. None is safe, they all may contain pollutants

e. Who care!