Title: GEOLOGY 101
1GEOLOGY 101
- Today Chapter 19
- A Hidden Reserve Groundwater
Course Website http//fouch101.asu.edu
2 3Why bother?
GROUNDWATER
- Groundwater is
- drinking water for more 50 of all people
- 40 of irrigation water
- important for livestock industry
- an overused resource resulting in
- - water shortages
- - land subsidence
- - contamination
4Why bother?
GROUNDWATER
- Groundwater is
- typically misunderstood
Underground lakes and rivers are rare Most
underground water exists in spaces between
grains (in pore spaces)
- geological important erosional agent
5Porous Sandstone
6Fractured Shale
7Groundwater storage movement
GROUND- WATER
Important factors
porosity - percent of the volume of material that
is pore spaces sandstone porous shale less
porous permeability - the ability of a material
to transmit a fluid sandstone permeable
shale - impermeable
8Wells
- Wells can supply water - if they intersect the
water table. - Pumping a well at a rate faster than water can
flow in the aquifer creates a cone of depression.
9Groundwater Contamination
10GROUNDWATER
Problems and contamination
- Saltwater contamination (coastal areas)
11GROUNDWATER
Problems and contamination
- Land subsidence
-
- The removal of water allows the aquifer sediments
to compact. - Once compacted, the overlying unsaturated zone
sediments will also drop in elevation.
12GROUNDWATER
Problems and contamination
- Subsidence (from pumping out water faster than
replenishing)
13GROUNDWATER
Problems and contamination
- Subsidence (from pumping out water faster than
replenishing)
Venice, Italy
14GROUNDWATER
Problems and contamination
- Groundwater contamination (due to human causes)
15GROUNDWATER
Problems and contamination
- Groundwater contamination (due to human causes)
16GROUNDWATER
Problems and contamination
- Groundwater contamination (due to human causes)
17Geologic alterations
GROUNDWATER
- 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.
18Geologic alterations
GROUNDWATER
- 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.
19Geologic alterations
GROUNDWATER
- 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.
20Geologic alterations
GROUNDWATER
- caverns
- karst topography
- sink holes
Limestone, usually formed just below water table
Arecibo Radio-telescope, Puerto Rico
Bedrock shaped (dissolved) by groundwater
Either gradual or abrupt depression in surface
due to dissolved limestone bedrock.
21Geologic alterations
GROUNDWATER
- 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.
22Geologic alterations
GROUNDWATER
- 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.
23Geologic alterations
GROUNDWATER
- 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.
24Groundwater recharge and discharge takes time
- The rate of movement of groundwater depends on
many factors including the flowpath.
25Springs, hot springs, geysers
GROUNDWATER
Spring
Outflow of ground water from water table
intersecting Earths surface
Marble Canyon AZ
26Springs, hot springs, geysers
GROUNDWATER
Springs
27Springs, hot springs, geysers
GROUNDWATER
Desert Oases
28Springs, hot springs, geysers
GROUNDWATER
Spring w/ water 6-9oC (10-15o F) warmer than mean
annual air temperature
Hot springs
29Springs, hot springs, geysers
GROUNDWATER
Geysers
Intermittent hot fountains/columns of water
30Springs, hot springs, geysers
GROUNDWATER
Geysers
Intermittent hot fountains/columns of water
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