Water is probably the neatest thing in this universe.  All life on earth depends on it, and it has physical properties that makes life itself possible.

Facts about water ... click here.
 

• Life got started in water (very simple algae,  "cyanobacteria" appeared about 3.5 billion years ago in what is now Australia)

 
• Water provided the only protection to life by filtering out harmful UV radiation.

 
• Water covers 71% of the earth's surface.  Water's high specific heat (ability to absorb or emit large amounts of energy without producing a major temperature change) provides the earth with a natural mechanism to stabilize climate and extreme temperature swings.  I'm sure you are familiar with the phrase "cooler near the lake" during hot summer days.

 
• Water expands 9% upon freezing.  If this were not so (and it behaved like most all substances), it would freeze in winter and SINK to the bottom of a lake.  Lakes would then easily freeze completely solid ... making all marine life impossible.  Instead, it stays on the surface acting like an insulator ... protecting marine life from the extreme cold above.

 
• Water is called a "polar molecule".  This means that water has tiny electric charges at its ends.  This property allows water to dissolve many things it comes in contact with (solubility) - a chemists dream!

 
• Water has been detected on Mars (at least in its past), on comets, in meteorites, and even deep space.  Maybe water is allowing other worlds to study water!

When it rains ...

When it rains, water reaching the surface does one of 4 things.

• It evaporates back into the atmosphere.
• It flows over the surface to a different location (we saw what that can do in unit 1).
• It is taken in by plants (and then released back to the atmosphere via transpiration).
• It soaks into the ground to become groundwater.

The percentage depends on the amount of rain and nature of the surfaces.  For example, if you dump a bucket of water on your lawn in summer, almost all the water will percolate into the soil.  Do the same thing over your driveway and it runs to a sewer. 

Groundwater

You already know that 97% of the earth's water is in the oceans but undrinkable (unless you spend big bucks to desalinate the water).  It is also difficult to drink the 2% tied up in ice (even though it is fresh in this form).  That means that only 1% makes up the useful water we all use.  By far, the bulk of this remaining slice is groundwater.

Where is this ground water?  Just drill down until you "hit water" in an area known as the water table.

As a kid, I thought this meant that there were great underground rivers and lakes .... not true!  (although these things do exist in some caves).  The water is simply trapped between pores, cracks and tiny spaces within the existing rock.  Have you ever played on the beach as a kid and dug a great hole?  You easily reach the water table and you can no longer dig any deeper because the hole quickly fills with water.
 
 

Click here for more details.

Water (from rain) percolates into the soil and continues to filter until it is "trapped" by an layer which will not allow water to penetrate ... an impermeable layer.  The layer of permeable rock containing the water is known as the "zone of saturation".  The water table marks the top of this zone.  Generally speaking, the shape of the water table matches the contour of the surface.  This is how groundwater is recharged (adding to the supply of groundwater).

On occasion, the water table intersects the surface and you see a lake.  (I often wondered as a kid why water doesn't filter away.)

I get my water (in Wales) from a well.  My well is 216 feet deep.  Some of my neighbors have wells over 500 feet deep ... a very expensive location since drilling a well is definitely NOT cheap.

This saturated zone constitutes an aquifer if it can provide an ample supply of usable water.  An aquifer must be:
 

• Porous - able to hold water (in open spaces)
• Loose sediments make the best aquifers.
• Permeable - able to transmit water (move easily)
• Clay has low permeability (because it attracts water molecules) even though it is porous.
• If the rock has large fractures, water may move too quickly.  The slow motion of water through the ground acts like a filter, removing bacteria, pesticides, dissolved salts, and pollutants.  A country home may have a septic system.  Waste water should slowly filter down to the water table so you don't end up sick (and also with an un-sellable house).  However, if the motion is too slow, your area may not "perk out" forcing you to buy an expensive "mound" septic system.  Check out which areas of the state may experience groundwater pollution.
• Saturated - hold lots of water
• Safe to drink - not polluted

South Eastern Wisconsin exists on an aquifer known as the Cambrian ­ Ordovician aquifer.
(the net flow is toward Lake Michigan... especially toward major cities where it is withdrawn in great quantities ... and rapidly dropping >800 feet since the civil war because of it .)

If you want to research any aquifer in the US, click here.

This rather complicated graphic is trying to say that most of the nations water (77.6%) comes from surface water (lakes & rivers) and only 22.4% comes from groundwater.  What is this water used for?  Mostly on farms (40.9% for irrigation/livestock)  & making electricity (38.7%).
 

Surface Water

Wisconsin watersheds

I live in the Upper Fox River Watershed
(click here for more information on Wisconsin watersheds)

There are 641 water treatment plants in Wisconsin (1990)
Wastewater Treated by Public Wastewater-Treatment Plants = 638 Mgal/d
 

Milwaukee is served by United Water (working with the Milwaukee Metropolitan Sewerage District).  United Water manages the Jones Island and South Shore facilities handling 215 million gallons per day (MGD) and have capacities of 330 MGD and 250 MGD, respectively.

Here are some of the steps they use to purify our water:

• Obtain water from intakes deep in Lake Michigan
• Add chemicals to precipitate solids out
• Add chlorine to kill bacteria
• Filter out impurities
• Aerate to improve the taste
• Use Ozone to kill cryptosporidium, a parasite commonly found in surface waters such as lakes and rivers, especially when the water is in contact with animal wastes and sewage.  (remember 1993? ... did you get sick?)
   

Waukesha (city) gets its water from a municipal well (ground water)
 

Problems related to water withdrawal:

• Pollution from landfills and fertilizers / pesticides / wastes (farms)
• Drops in water levels due to over usage (ground water)
• Expensive to drill deeper in the water table
• Land subsidence
• Radium levels (see a state map)
• Places like Saudi Arabia (and other Mid Eastern countries) must desalinate its water using an expensive reverse osmosis process (and other techniques) ... they have cheap oil but expensive water!

 

http://ga.water.usgs.gov/edu/

http://www.epa.gov/surf/

©Jim Mihal 2004, 2006 - all rights reserved