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Groundwater Notes
Look for this
Water that flows over
the land
The slow movement of
water through the
pores in rock or
sediment (percolation)
98% of available
freshwater is groundwater
Porosity vs. Permeability
High vs. Low Porosity
The percentage of open space/holes/cracks in a given volume of rock
Porosity in Sand, Fractured bedrock, & Caves in limestone
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•“Impermeable”- Smaller grains = Low permeability ex: Clay, Silt
•“Permeable”- Larger grains = High permeability ex: Sand, Gravel
PermeabilityThe ability to transmit water
( Impermeable / Permeable )
layer has very ( small / large )
grain sizes, water will RUNOFF
Porosity Gizmohttps://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=431
Impermeable Permeable
Particle Size and Permeability
Which column has the highest permeability?
Infiltrate(if not already saturated)
The lowest?
Impermeable(water will runoff)
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AquiferRock or soil through which groundwater moves easily
Confining layer
Zones of Aeration and Saturation More rain, water table will _____________( rise / fall )
Drought in California: Why we need groundwater- NBC News (April 1, 2015)http://www.nbcnews.com/nightly-news/video/california-drought--billions-at-stake-as-farmland-dries-up-421427267534
http://www.circleofblue.org/waternews/2014/world/infographic-california-drought-drains-groundwater-reserves-encourages-new-wells/
2014
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http://www.circleofblue.org/waternews/2014/world/infographic-california-drought-drains-groundwater-reserves-encourages-new-wells/
2014
http://www.circleofblue.org/waternews/2014/world/infographic-california-drought-drains-groundwater-reserves-encourages-new-wells/
2014
Drought Status in California
http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?CA http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?CA
See mudslides wreck havoc on Southern Californiahttps://www.youtube.com/watch?v=f73jko6Oz-E
Montecito Man Shares Dramatic Footage of Flash Flood at Homehttps://www.youtube.com/watch?v=dDSAwM1nf_c
Confining unit
Let’s Review
Confining unitsAlso called an Aquiclude
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Cone of DepressionLocal lowering of the water table due to the
pumping of water from a well
Drawdown
Pump Driven Wells
1. SubsidenceGradual sinking of land
surface due to removal of groundwater
http://www.history.com/news/ask-history/why-does-the-leaning-tower-of-pisa-lean
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http://www.nola.com/speced/lastchance/multimedia/
Before and After Hurricane
Katrina (2005)
Louisiana Storm SurgeNew Orleans Lakefront Airport: 11.8', Hurricane Katrina, 2005
2. Salt Water IntrusionSalt water pulled into wells due to over
pumping of groundwater
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3. Groundwater Contamination
Hinkley groundwater contamination-Erin Brockovich (film) (2000)
Between 1952 and 1966, the water used in these cooling towers contained hexavalent chromium – now recognized as a carcinogen –to prevent rust in the machinery. The water was stored between uses in unlined ponds, which allowed it to percolate into the groundwater. This led to groundwater pollution, affecting soil and contaminating water wells near the compressor station, with a plume approximately 2 miles (3.2 km) long and nearly 1 mile (1.6 km) wide.
http://en.wikipedia.org/wiki/Hinkley_groundwater_contamination
Groundwater Safety
Typically, 90% of the fluid is water and 9.5% is sand with chemical additives accounting to about 0.5%.[47][56][57]
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https://en.wikipedia.org/wiki/Landfill_liner
Bioaccumulation -the accumulation of substances, such
as pesticides, or other chemicals in an organism
Artesian WellsAquifer between 2 impermeable layers; continually recharged and
flowing under pressureDoesn’t require a pump
Permeable Rock
Impermeable Rock
Recharge Zone
Aquifer Artesian Well Animationhttp://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::640::480::/sites/dl/free/0072402466/30425/11_09.swf::Fig. 11.9 - Artesian Well and Confined Aquifer
Saturation Level
Artesian Well
Springs and Perched Water Tables
Confining unitsCalled an Aquiclude
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Springs
A flow of
groundwater
that emerges
naturally at
the ground
surface
Hot Springs & Geysers
Geysers
A fountain of hot
groundwater that is
periodically ejected
http://www.classzone.com/books/earth_science/terc/content/visualizations/es1403/es1403page01.cfm?chapter_no=visualization
Karst TopographyRegion characterized by numerous sinkholes
and caverns
http://www.pbslearningmedia.org/resource/ket09.sci.ess.structure.karst/karst-topography-and-mammoth-cave/
Karst Topography
Chemical weathering (dissolution) of limestone bedrock
Cave Formationhttp://www.classzone.com/books/earth_science/terc/content/visualizations/es1405/es1405page01.cfm?chapter_no=visualization
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Cave formationLimestone rock dissolved by groundwater mixed
with carbonic acid
KarstTopography
Tower Karst
(China)
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Caves in Texas
Natural Bridge Caverns
Natural Bridge Caverns in San Antonio
New Zealand (2009) South IslandKarst Topography
New Zealand (2009) South IslandKarst Topography
Mr. Travis
Mrs. Travis’ professor
New Zealand (2009) South IslandKarst Topography
This is Mike
Sinkholes / Swallet holes/ Cenotes*
*exposes groundwater underneath
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Sinkholes / Swallet holes
Corvette Museum- Beforehttp://www.usatoday.com/story/news/nation/2014/02/12/corvette-museum-sinkhole/5417171/
Corvette Museum- Afterhttps://www.youtube.com/watch?v=0jKjV5AqoNU
Cenote
Hamilton Pool