The hydrological cycle and a few other memorable definitions See Fig. 13.2 = Cyclical movement of water from ocean to atmosphere, land and back to the

The hydrological cycle and a few other The hydrological cycle and a few other memorable definitionsmemorable definitions

See Fig. 13.2

= Cyclical movement of water from ocean to atmosphere, land and back to the ocean

Ground water = mass of water beneath the surface

Infiltration= Soaking into ground

Runoff = Rainwater that collects into streams and rivers

Reservoir = Place where large quantities of water are stored

Aquifer = Beds that store and transmit groundwater

Water table = upper limit of the zone of sediment saturated with water.

1) Why bother?1) Why bother?GROUNDWATERGROUNDWATER

1.1. Why botherWhy bother

2.2. The water tableThe water table

3.3. Groundwater storage and movementGroundwater storage and movement

4.4. Springs, hot springs, geysersSprings, hot springs, geysers

5.5. WellsWells

6.6. Problems, contaminationProblems, contamination

7.7. Geologic alterationsGeologic alterations


GroundwaterGroundwater is

drinking waterdrinking water for more 50% of all people

40% of irrigationirrigation water

important for livestocklivestock & industryindustry

an overusedoverused resource resulting in:

- water shortages

- land subsidence

- contamination


GroundwaterGroundwater is

typically misunderstoodtypically misunderstood

Underground “lakes” and “rivers” are rare

Most underground water exists in spaces between grains(in “pore spaces”)

geological important erosional agentgeological important erosional agent


94% of all non-glacier fresh water

See Fig. 13.1

2) The water table2) The water tableGROUNDWATERGROUNDWATER

The water tablewater table is the upper limit of the zone of sediment saturation with water.

Its shape depends on water influx and drainage

Groundwater moves very slowly:

humid region

arid region

See Fig. 13.8

Influent streams recharge ground waterInfluent streams recharge ground water

Effluent streams discharge ground waterEffluent streams discharge ground water

3) Groundwater storage & movement3) Groundwater storage & movementGROUND-GROUND-WATERWATER

Important factors:Important factors:

porosityporosity - percent of the volume of material that is taken up by pore spaces

permeabilitypermeability - the ability of a material to transmit a fluid

AquiferAquifer - rock/sediment which easily transmits water

Aquiclude, aquitardsAquiclude, aquitards - barrier to water flow (low permeability)

See Table 13.2, Fig. 13.17

3) Groundwater storage & movement3) Groundwater storage & movementGROUND-GROUND-WATERWATER

Important factors:Important factors:

Table 13.2

Marble Canyon AZ

4) Springs, hot springs, geysers4) Springs, hot springs, geysersGROUNDWATERGROUNDWATER

Spring:Spring:

Outflow of ground water

from water table intersecting

Earth’s surface

See Fig. 13.11


Springs


Desert Oases

See Fig. 13.10 on artesian wells


Hot springs:Hot springs: Spring w/ water 6-9oC (10-15o F) warmer than mean annual air temperature


Geysers:Geysers: Intermittent hot fountains/columns of water

See Fig. 13.22

5) Wells5) WellsGROUNDWATERGROUNDWATER

Well:Well: A drilled hole into a saturated zone

A “cone of depression” develops around the pumping hole

See Fig. 13.14

6) Problems, contamination6) Problems, contaminationGROUNDWATERGROUNDWATER

Saltwater contamination (coastal areas)

See 13.14Freshwater-seawater boundary is maintained by the balance between recharge and discharge.


Subsidence (from pumping out water faster than replenishing)


Subsidence (from pumping out water faster than replenishing)


Groundwater contamination (due to human involvement)

See Fig. 13.20. Contaminants enter aquifers and water supplies trough wells.


Groundwater contamination (due to human involvement)

7) Geologic alterations7) Geologic alterationsGROUNDWATERGROUNDWATER

caverns

karst topography

sink holes

Limestone, usually formed just below water table

Bedrock shaped (dissolved) by groundwater

Either gradual or abrupt depression in surface due to dissolved limestone bedrock.

Some MCSome MCGROUNDWATERGROUNDWATER

After oceans, which of the following reservoirs After oceans, which of the following reservoirs contains the most water?contains the most water?

A. atmosphereA. atmosphereB. glaciers and polar iceB. glaciers and polar iceC. lakes and riversC. lakes and riversD. underground waterD. underground water


Karst topography forms in regions underlain by Karst topography forms in regions underlain by __________.__________.

A. basaltA. basaltB. limestoneB. limestoneC. sandstoneC. sandstoneD. shaleD. shale


What is the average annual precipitation in Phoenix, What is the average annual precipitation in Phoenix, Arizona?Arizona?

A. less than 20 cmA. less than 20 cmB. 20-40 cmB. 20-40 cmC. 40-60 cmC. 40-60 cmD. more than 60 cmD. more than 60 cm


15.15.Layers that transmit groundwater are called Layers that transmit groundwater are called ______.______.

A. aquicludesA. aquicludesB. aquifersB. aquifersC. influent streamsC. influent streamsD. unsaturated zonesD. unsaturated zones


Which of the following unfractured rocks has the Which of the following unfractured rocks has the

highesthighest porosity? porosity?

A. graniteA. graniteB. sandstoneB. sandstoneC. schistC. schistD. shaleD. shale


What is the difference between the saturated and unsaturated What is the difference between the saturated and unsaturated

zones of groundwater?zones of groundwater?

A. The saturated zone has a A. The saturated zone has a higherhigher porosity than the porosity than the unsaturated zone.unsaturated zone.

B. The saturated zone has a B. The saturated zone has a lowerlower porosity than the porosity than the unsaturated zone.unsaturated zone.

C. The pore spaces in the saturated zone C. The pore spaces in the saturated zone areare full of water; the full of water; the pore spaces in the unsaturated zone pore spaces in the unsaturated zone are notare not full of water. full of water.

D. The pore spaces in the saturated zone D. The pore spaces in the saturated zone are notare not full of water; full of water; the pore spaces in the unsaturated zone the pore spaces in the unsaturated zone areare full of water. full of water.


Which of the following statements about groundwater in Which of the following statements about groundwater in

coastal regions is coastal regions is truetrue??A. Fresh water is denser than seawater, therefore fresh A. Fresh water is denser than seawater, therefore fresh

groundwater floats on top of salty groundwater. groundwater floats on top of salty groundwater. B. Fresh water is denser than seawater, therefore salty B. Fresh water is denser than seawater, therefore salty

groundwater floats on top of fresh groundwater.groundwater floats on top of fresh groundwater.C. Seawater is denser than fresh water, therefore fresh C. Seawater is denser than fresh water, therefore fresh

groundwater floats on top of salty groundwater.groundwater floats on top of salty groundwater.D. Seawater is denser than fresh water, therefore salty D. Seawater is denser than fresh water, therefore salty

groundwater floats on top of fresh groundwater.groundwater floats on top of fresh groundwater.

Documents

The hydrological cycle and a few other memorable definitions See Fig. 13.2 = Cyclical movement of water from ocean to atmosphere, land and back to the