Students will learn how rain water enters the Cohansey Aquifer; how it is "stored"; and how it is returned to the surface of the earth for use by private homeowners and farmers.

1. Activity Background Information:
The Cohansey Aquifer primarily consists of sand and gravel and "holds" 17 trillion gallons of fresh water that are replenished by the approximately 45 inches of precipitation that falls on New Jersey's Pinelands annually. The soil acts like a sieve allowing the rain water to pass through its upper layers (zone of aeration) to the water table and the usable water supply (zone of saturation). The top of the zone of saturation is called the "water table." If the amount of precipitation falling on the Pinelands increases substantially, the water table will rise. If there is a drought, the water table will fall.

PROCEDURE:

1. View with students the 17-minute audio-visual program, "The New Jersey Pinelands, Our Country's First National Reserve" ). Direct students to pay special attention to all water related facts mentioned in the program. (You may want them to jot down some notes.) At the program's conclusion, ask students what they learned about Pinelands water and list the facts on the chalkboard. Facts may include:
*Cohansey Aquifer is underneath the surface of the Pinelands
* rain water drains quickly through this porous, sandy soil
* pollution can reach this aquifer as quickly as rain water
* Cohansey Aquifer contains 17 trillion gallons of water it supplies half a million southern New Jersey residents with some of the purest drinking water in the world
* it feeds the rivers and streams of the Pinelands. Where underground water reaches the surface, wetlands are found
* wetlands cover one-quarter of the Pinelands and include rivers, streams, bogs, hardwood and cedar swamps, and pitch pine lowlands
* Pinelands river water is important because it flows to the marshes and bays along the Atlantic coast where fish, crabs, clams, and other ocean creatures start their lives
* if the river water flowing into the bays is polluted or decreased in quantity it can harm this important food source and seriously affect New Jersey's shellfishing industry
* the reddish brown color of Pinelands water is caused by decomposed plant material and dissolved iron
* low grade iron ore is formed when naturally occurring iron in the soil and water reacts with oxygen and floats on the water's surface. The iron oxide combines with sand and gravel to produce iron ore which is deposited along stream banks
* early Pinelands settlers used the rivers to turn water wheels to power their saw mills, grist mills, and paper mills
* today's cranberry farmers depend on this abundant, pure water supply to grow and harvest their crop
* as people have moved into the Pinelands, wetlands have been drained and filled in order to make them suitable for development. This has made them unsuitable for wildlife habitats and has destroyed their ability to maintain water quality
* if the quality of Pinelands water is changed or pollution enters the Cohansey Aquifer - animals, plants, and even people, who cause the pollution, will suffer.
*people use the rivers of the Pinelands to hunt, fish, trap, canoe, and swim

Have students take notes on the facts as you list them on the board. Take time to discuss ideas or experiences students have had that are related to these facts.

2. Duplicate and distribute the worksheet, "Zone of Aeration and Zone of Saturation," to each student .

Teacher Demonstration:
a. First, fill a large beaker with white or beige colored aquarium gravel. Explain to students that this is very much like the sand/gravel found in the Cohansey Aquifer.

b. Then pour water into the beaker. (You may want to color the water with food coloring so it is clearly visible to students.) Ask: How can so much water "fit" into this gravel-filled beaker? (Answers may include: "it fits into holes, spaces, cracks, pores.") Lead the students to see that the water displaces the air in the pore spaces. Basically, this is what happens with a sand and gravel aquifer in its "zone of saturation."

c. Next, immerse a wash cloth in a pan filled with water. Remove the cloth and hold it above the pan. Ask. What is happening? (Answers may include: Water is dripping back into the pan. Pore spaces in the cloth are saturated (can't hold any more water) and there is no place for the excess water so it drips back into the pan.) Wring out the cloth. The cloth is still wet, but no water drips from it. Ask: Why has the water stopped dripping from the- cloth? (Answers may include: Water has been squeezed out of the holes, spaces pores and filled with air; water that's left clings to cloth particles and pore spaces are now filled with air.) Explain that this is what scientists call "capillarity" and it is similar to what happens near the earth's surface. Roots of plants and trees "drink up" the moisture and what is left is tightly held to the surface of soil particles. Pore spaces are filled with air. That's why this is called the "zone of aeration." When the plants have their fill, water filters through the air filled pores to the "water table" which is the top of the zone in which the openings, pores, between soil particles are completely full of water (zone of saturation).

d. Finally, have students label the worksheet diagram

Based on your demonstrations, ask students to describe what is happening. (Precipitation is falling on a Pinelands forest. In the upper layers of the forest floor, the plants take the amount of water they need to live and the water coats the surface of the soil particles. Any additional water then moves through the pore spaces to the water table. Where underground water reaches the earth's surface, wetlands (rivers, streams, bogs) are formed.

3. Duplicate and distribute the well diagram to students. Explain to students that today's wells are different in appearance than the old-fashioned handpump wells or shallow hand dug wells where water was brought to the earth's surface in a bucket. Now, most homeowners in the Pinelands Preservation Area depend on individual wells.

A homeowner will have the well drilled near his home. Ask students if any have ever seen a well drilling rig. If so, ask the student (s) to describe how it works. (Answer: A cable-tool drilling rig churns a bit up and down in the hole or the hole may be bored with a rotary drill. Once it is drilled, it's lined with a long metal or plastic pipe called a casing. This casing supports the well's walls so that sand and gravel don't fall in and it also keeps poor quality water out. The pump pipe hangs down inside the casing below the water table level in the zone of saturation.)

Ask students what keeps the water in the zone of saturation once the well is drilled. (Answer: Basically, below the water table, all water is under pressure. This pressure forces water to move from one pore space to another.)
Ask students how this water gets from the zone of saturation to the earth's surface for human use. (Answer: Very simply, a well is like an extra large pore into which pressure forces the water to move to replace the water drawn up by the pump.)
Discussion: Note that if a lot of water is drawn from the zone of saturation especially during a very dry season, the water table will lower. Ask: Why do you think government officials sometimes put a ban on car washing and lawn watering during dry, hot summer months? (Answer: Little or no rain has fallen that would refill the aquifer, so there is a danger that the water table might drop below the well. This would leave people with little or no water and make it necessary to drill deeper wells.) Ask: What do you think happens to the water table when there is a great deal of precipitation? (Answer: The water table will rise.)

EVALUATION:

Duplicate and distribute copies of Worksheet III "The Cohansey Aquifer and Wells". Check students' worksheets for accuracy.

FOLLOW-UP:

1. If your community has a water department, invite the superintendent to speak to your class about the local water supply. Learn where your water comes from, if it is chemically treated before it's piped to your home, how it gets to your home.

2. Monitor precipitation that falls in your community on a daily basis for at least one month. See how it compares with the "Pinelands Climate Summary". Check your local paper as well as radio and television stations for weather reports. You may even want to invest in a rain gauge for this project..

3. How good are your powers of observation? Do you know where rain water goes after a major storm in your community? If you live in a heart of the Pinelands, you'll see that it percolates into the sandy soil, but if you live in the suburbs or city, chances are this isn't the case. Once again, as an individual, team, or class, investigate "the whereabouts of the fallen rain." If it isn't recharging the aquifer, where is it going?

4. Visit a local industry that uses a lot of water to learn where the water comes from, how it is used, and what happens to it when it's no longer needed. If your school is near Chatsworth in Burlington County, New Jersey, you may want to visit the Ocean spray receiving plant during cranberry harvest, mid-September through early November. Be sure to call in advance in order to make reservations:

Receiving Station Manager Ocean Spray Cranberries, Inc.
Main Street
Chatsworth, NJ 08019
(609) 726-1600

5. Two excellent pamphlets -- A Primer on Water and A Primer on Water Quality - may be purchased from the New Jersey Geological Survey. These may be added to your classroom library. Have an interested student(s) prepare a water related report based on information in these pamphlets. Click here to jump to the website of the New Jersey Geological Survey.

This lesson will introduce the students to the following vocabulary words:(click on the word to see its definition-use your browser's back button to return to this page)

capillarity, Preservation Area, water table, wetlands,
zone of aeration, zone of saturation

Science standards:

5.1-All students will learn to identify systems of interacting components and understand how their interactions combine to produce the overall behavior of the system.

5.2-All students will develop problem solving, decision making, and inquiry skills, reflected by formulating useable questions and hypotheses, planning experiments, conducting systematic observations, interpreting and analyzing data, drawing conclusions, and communicating results.

5.10-All students will gain an understanding of the structure, dynamics, and geophysical systems of the earth.

5.12-All students will develop an understanding of the environment as a system of interdependent components affected by human activity and natural phenomena.

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