4/12/2018

1

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

4/12/2018

2

•“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)

4/12/2018

3

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

4/12/2018

4

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

4/12/2018

5

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

4/12/2018

6

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

4/12/2018

7

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]

4/12/2018

8

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

4/12/2018

9

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

4/12/2018

10

Cave formationLimestone rock dissolved by groundwater mixed

with carbonic acid

KarstTopography

Tower Karst

(China)

4/12/2018

11

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

4/12/2018

12

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