Water Underground Section 5 Pages 68-74

Underground Layers  Where does underground water come from?  Do you recall what happens to precipitation when it falls to Earth? Precipitation falling to Earth… evaporates immediately runs off the surface soaks into the ground

Underground Layers  The rain water that soaks into the ground trickles downward, following the pull of gravity.  What happens when you pour water into the pitcher of pebbles?

Underground Layers  The water will trickle down around the pebbles until it reaches the bottom of the pitcher. Then the water will fill up the spaces between the pebbles.  In the same way, water underground trickles down between particles of soil and through cracks and spaces in layers of rock.

Pore Space  Different types of rock and soil have different sized spaces, or pores, between their particles.  How easily water moves through the material depends on: size of the pores whether or not the pores are connected

Permeable  Materials that allow water to easily pass through, or permeate, are called permeable.  Examples: sand and gravel

Impermeable  Water will eventually reach layers of material that it cannot pass through. These materials have few or no pores or cracks for water to flow through.  Materials that water cannot pass through easily are called impermeable materials.  Examples: clay and granite

Permeable vs. Impermeable

Trapped Water!  Once water reaches an impermeable layer it is trapped! Where can it go?  The water will start to fill up the spaces above it, the permeable layers it just soaked through.

More Vocabulary  saturated zone = the area of permeable rock or soil that is totally filled, or saturated with water  water table = the top of the saturated zone (where you dig to strike groundwater!)  unsaturated zone = the layer of rocks and soil above the water table (the pores here contain air and water)

Words Worth Knowing (ISN#52)  pore  permeable  impermeable  saturated zone  water table  unsaturated zone

Underground Water Part 2

Aquifers  Any underground layer of rock or sediment that holds water is called an aquifer.  The water in an aquifer is in motion, seeping through the layers of rock.  Speed of the water is determined by: Slope of aquifer How permeable the rocks are

Aquifers  Aquifers can range in size from a small underground patch of permeable material to a HUGE area the size of several states.  Millions of people obtain their drinking water from the Ogallala aquifer.

Bringing Groundwater to the Surface  The level of the water table generally follows the shape of the underground rock layers.  The depth of the water table can vary greatly depending upon the weather.

Bringing Groundwater to the Surface  How does water actually get to the surface? In places where the water table meets the ground surface, water seeps onto the surface. The groundwater may feed a stream or pond, or form a wetland. People can also bring groundwater to the surface.

Wells  People can obtain groundwater from an aquifer by drilling a well below the water table.  Long ago, people dug wells by hand and used a bucket to bring up water.  Today, most wells are dug with well-drilling equipment with pumps bringing the water to the surface.

Wells  Can a well run dry?  Yes! Pumping too much water out too fast can cause the well to run dry.  What can you do if it runs dry?  Either dig deeper or wait for the aquifer to recharge (rainfall).  Recharge = new water that enters the aquifer from the surface

Artesian Wells   Artesian well = a well in which water rises because of pressure within the aquifer  There is a great deal of pressure on water that is trapped between two layers of impermeable material. Puncture the top layer and you strike water!

Springs  Springs = where groundwater bubbles or flows out of cracks in the rock  Groundwater can seep, flow or erupt onto the surface.  Water is usually at normal temperatures but some springs contain warm water that has been heated below the surface.  Yellowstone has hot springs. Also, Warm Springs, Georgia and Hot Springs, Arkansas do too!

Geysers  Geyser = a type of hot spring from which the water bursts periodically into the air  Geysers form when very hot water deep underground begins to rise through cracks in the rock. Heated gases and bubbles of steam are forced up by the pressure of the hot water. 

South Lyon, Michigan

South Lyon Aquifer  The City of South Lyon's water system is serviced by three (3) wells ranging in depth from 120 to 125 feet deep. They have a one million gallon ground storage tank with a 500,000 gallon elevated water tower which supplies water pressure to the City at psi.  Huron River Watershed  Credit *this is not the South Lyon water tower

South Lyon Aquifer  Mr. Bob Martin and his crew 

Words Worth Knowing (ISN#52)  aquifer  recharge  artesian well  springs  geysers  You should have 28 words worth knowing