Ch 9/10 Earth’s Water Part 2: Lessons 6 - 8 Ch 10 Groundwater 1

The Movement and Storage of Groundwater Lesson 6 The Movement and Storage of Groundwater 2

Does your family drink well water? Think About It… Does your family drink well water? 3

How does groundwater move through the lithosphere? Focus Question… How does groundwater move through the lithosphere? How are flood events affected by groundwater levels? 4

Precipitation and Groundwater… Remember the water cycle? Most water in the atmosphere comes from oceans! Most precipitation that falls on land becomes groundwater. Eventually groundwater will… … return to the ocean to complete the water cycle.

Groundwater Storage… 1. Porosity is… …the percentage of pore space in a material 2. The types of soil that have - a. highest porosity - well- sorted b. lowest porosity – poorly- sorted http://core.ecu.edu/geology/woods/GWANSW2008_files/image002.jpg

Groundwater Storage… in the pore spaces of rocks & sediments 1. Groundwater is stored… in the pore spaces of rocks & sediments …and can be compared to a hard sponge http://core.ecu.edu/geology/woods/GWANSW2008_files/image002.jpg

Figure 10-1 Page 241 TOP LABEL the well-sorted and poorly-sorted sides!

Groundwater Storage… 3. The zone of saturation is the… … depth below surface where groundwater completely fills all the pores 4. The water table is the … … upper boundary of the zone of saturation

2. Groundwater Storage (p. 421) soil Zone of aeration Water table Zone of saturation

Groundwater Storage… 5. The depth of the water table varies… …in swampy areas- water table is at or almost at surface, …in arid regions -water table is far beneath surface Green Swamp, FL

Groundwater Storage… If the water table is high, it is more likely to flood. low, it is less likely to flood. 7. The water table fluctuates with the seasons and weather conditions because… it depends on rain to recharge it http://www.tulane.edu/~sanelson/images/chwattab.gif

Groundwater Movement: Permeability… 1. What is permeability? ability of a material to let water pass through What subsurface materials are permeable? sand, sandstone, & gravel (good for parking lots so water can infiltrate) What subsurface materials are impermeable? clay, silt, shale, & pavement (bad for infiltration!) Why is clay used to line ponds & landfills? It is impermeable (our storm drainage pond)

Groundwater Movement: Aquifers… An aquifer … underground storage area for water (permeable rock layers) An aquiclude … impermeable layer above or below an aquifer.

Groundwater Movement… Confined aquifer aquiclude

Groundwater Systems, Use, and Threats! Lesson 7 Groundwater Systems, Use, and Threats! 16

Think About It… Where does the water in a spring come from? Have you ever been swimming in a spring? 17

What are the unique features of springs? Focus Question… What are the unique features of springs? How can the use of wells lead to aquifer depletion, subsistence, and saltwater intrusion? What are threats to our groundwater? 18

Springs… Ground water discharges (comes out) at… 1.Earth’s surface 2. These natural discharges of water are called…springs 3. Water may flow out of a rock when… It’s where an aquifer meets an aquiclude at Earth’s surface (a spring!)

http://www.eyekonic.net/gallery2/d/1232-2/Ponce_20De_20Leon_20Springs_202.jpg Ponce De Leon Springs

Location of Springs:  Fault-blocked Perched Water Table  Road Cuts  Limestone Regions  http://www.physicalgeography.net/fundamentals/8m.html

Springs flowing out of road- cut mountainside – 421 N

Hot Springs… 4. The temperature of ground water is… same as average annual temperature 5. Hot springs are… have temperatures higher than the human body Hot springs are so hot because… the subsurface is still hot from recent igneous activity Picture on next slide 

Hot Springs at Yellowstone N.P. http://www.guideoftravels.com/wp-content/uploads/2011/09/Yellowstone-National-Park.jpg

Mammoth Hot Springs Yellowstone

Old Faithful Geyser Yellowstone NP Springs and Geysers… Old Faithful Geyser Yellowstone NP 5. Most hot springs in our country are found in the… western states 6. A geyser is an … explosive hot spring that erupts at regular intervals

Geyser Basin, Yellowstone National Park

Wells… 1. A well is… a hole dug to reach groundwater 2. A cone of depression is produced by… over pumping wells 3. Drawdown is… the difference b/tw the original water table level and that of a pumped well 5. Recharge is… water from rain or runoff is added to an aquifer

http://pubs. usgs. gov/gip/gw_ruralhomeowner/gw_ruralhomeowner_new http://pubs.usgs.gov/gip/gw_ruralhomeowner/gw_ruralhomeowner_new.html Wells: Figure 10-15, p. 252 http://ga.water.usgs.gov/edu/earthgwlandsubside.html

Wells… The entire water table can be lowered due to… …overuse of wells Ground above an overused well can… …sink! This is called subsidence

Groundwater Use 8 & 9. In the USA, 23% of all freshwater is obtained from… … aquifers (groundwater) … Florida, Hawaii, and Nebraska depend almost entirely on groundwater.

Environmental Issues: Saltwater Intrusion… … saltwater intruding into coastal wells… … Outer Banks (on coast) … too many wells 32

Six Threats to Our Groundwater Supply… Overuse Subsidence Pollution (sewage, industrial waste, landfills, agriculture) Chemicals (not filtered out by sediments; hard to remove from groundwater) Salt (esp. coastal areas) Radon (radioactive decay of uranium in rocks – esp. granite and shale)

Protection of Groundwater… Identify and eliminate pollution sources. Monitor pollution. Pump groundwater to surface and treat it.

Lesson 8 Groundwater Erosion 35

Why do some homes in Florida get swallowed up by the ground? Think About It… Why do some homes in Florida get swallowed up by the ground? 36

What are the unique features of caves? Focus Question… What are the unique features of caves? What features are found in an area with Karst topography? 37

Caves… What is a cave? A natural underground opening with a connection to Earth’s surface Which acid forms caves? Carbonic acid (H2O + CO2 in the soil) Which rock is eroded by this acid to form a cave? limestone

Caves of the USA… Mammoth Cave, Kentucky Carlsbad Caverns, N. Mexico Lechuguilla Cave, N. Mexico http://www.britannica.com/blogs/2011/07/dark-depths-mammoth-cave/ http://giantcrystals.strahlen.org/america/lechuguilla.htm http://en.wikipedia.org/wiki/File:Witchs_Finger_Carlsbad_Caverns.jpg

Mammoth Cave: A Closer Look… http://images.travelpod.com/users/socks/1.1248576883.mammoth-cave-river-styx-tour-route.jpg

Cave Formations… http://www.cr.nps.gov/history/online_books/orca/underworld/sec1b.htm

Karst Topography: Sinkholes… 1. What is a sinkhole? A depression in the ground caused by the collapse of a cave http://southeastsinkhole.com/

http://www.virginiacaves.org/lok/ccvup56.htm Karst Topography 2. Karst topography are limestone regions that have sinkholes, sinks, and sinking streams – named for an area in Croatia. A aerial photograph of a classic Karst terrain north of Lewisburg, WV

Karst Topography…

Karst Topography Missouri http://www.mospeleo.org/ozark_caving/springs/sprkarst.htm

Hard Water… 4. Hard water is water that contains high concentrations of calcium, magnesiun, or iron. Common in limestone areas Causes deposits of calcium bicarbonate and can clog water pipes. (p. 247) More soap must be used