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Problem of the Week
Chapter 10

It Rains Down From Above, Flows Over the Surface, Sinks to Great Depths, and Wells Up From Beneath—What Is It?

Sounds like a horror movie title, doesn’t it? It’s not some creature from the Black Lagoon that we are talking about here, but water, the lifeblood of Earth. Without it life, as we know it, would not exist. Did you know that humans can live for weeks without food, but only a few days without water? Did you know that over 71% of Earth’s surface is covered by water? Unfortunately, only 3% of that amount is freshwater, the rest is in the oceans or seas, too salty to be readily usable by humans.

*Remember these two bars represent 3% of all the water on Earth. The rest is salt water.

Take a look at the following diagram. It is a break down of the freshwater sources on Earth.

chart

USGS: Water Science for Schools

http://wwwga.usgs.gov/edu/waterdistribution.html

Notice that just over ¾ of the freshwater is frozen in glaciers (77%). The other ¼ is groundwater (22%), rivers, lakes, and atmosphere and soil moisture (all together these last sources make up less than 1% of the freshwater on Earth).

Now think about this:

Chapter 10 is about groundwater, that is, water beneath the surface that may or may not be available, or accessible for use by humans. As you can see from this diagram, groundwater comprises about 1/5 of the freshwater on Earth.

Groundwater is an important source of water for all types of human uses, including drinking water, agricultural and industrial uses.

Problem:

Take a look at the following United States Geological Survey (USGS) data table.

*Data table from USGS: Water Science For Schools -

http://wwwga.usgs.gov/edu/tables/dlps.html


chart
chart
chart
chart

The table shows two things:

  1. The population that is served by groundwater and surface water.

  2. The amount of water, in millions of gallons per day, that is used from both groundwater and surface water sources.

  1. Examine the data in the USGS table (also note, this data is ten years old, remember that populations have increased in most places, so water use most likely has increased also).

  2. Determine the following for your state:

    1. What percent of the population is served by surface water as compared to groundwater?

    2. What percent of the total amount of water withdrawn from state resources is surface water?

  3. Determine the following for the entire United States (data at bottom of table):

    1. What percent of the population is served by surface water as compared to groundwater?

    2. What percent of the total amount of water withdrawn from state resources is surface water?

  4. Now considering this information:

    • How important are each of these sources of water in supplying the water needs of your state?

    • The United States?

    • How do the water use trends for your state compare to the overall United States trends?

Other Things to Think About:

What is the water quality in groundwater resources?

What are the threats to water quality for these resources?

Who monitors the water quality in groundwater?

What is being done to protect these water resources?

Are there any rules governing the withdrawal of groundwater?

 


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