Ground Water Education Activities

1. .

Activity 2: Get the Ground Water Picture – Project WET Book, p 136.

Activity 3: Where Does Contamination Go?

Goals:

Basic goal: To demonstrate conservation of mass, and contaminant movement.

The first activity shows that contamination does not necessarily go away. A contaminant can change form through chemical and biological processes, but it does not really disappear. It can volatilize (to the air), be sorbed onto soil, be consumed and transformed by bacteria, or flow with water to another location. Its fate depends on the type substance and the environmental conditions present.

(More advanced) Alternative goal: To encourage students to formulate hypotheses, and to design an experiment to demonstrate their hypotheses.

Materials needed:

• clear plastic cup
• rice
• food coloring
• water
• plastic soda straw, pipette with bulb, or small turkey baster to use as a simulated well
• small square of gauze
• rubber band
• spray bottle of water

1. Prepare the straw, pipette, or turkey baster for use as a pumping well by covering the end with a square of gauze and securing it with the rubber band. Set aside.
2. Pour rice into plastic cup, about 1/2 to 3/4 full.
3. Add water to a level about 1 cm below the surface of the rice.
4. Insert the "well" and pump out some water. (Leave the well in place.)
5. Drop a couple of drops of the food coloring onto the surface of the rice and watch what happens.


Write down your observations.

6. Mist the surface of the cup with the spray bottle to simulate rainfall, and observe what happens to the food coloring.


Record your observations.

7. Pump a little water out from the well again and observe what happens.


Did the food coloring enter the well? Describe whether it was diluted, and estimate how much dilution, if any has occurred.

8. Let the cup sit for about 15 minutes.
9. Pump a little water out again and observe what happens.
10. Let the cup sit for another 15 minutes.
11. Pump a little water out again and observe what happens.

• Describe where ground water comes from. In other words, how did it get into the ground in the first place?
• How does contamination get into ground water?
• Can you list some natural and some anthropogenic (man-made) ground water contaminants?

Repeat this activity using a deeper plastic cup and vary the depth from the surface of the rice to the water.

Goal: To show the effect of dilution on certain contaminants.

Background:

Sometimes there may be very small amounts of contaminants in our drinking water. Depending on what the contaminant is, this may be a serious problem. Because some contaminants are dangerous in very small amounts, it is important to know the amount of contaminant in a specified volume of (drinking) water. The federal government specifies maximum contaminant levels (MCL’s) for certain chemicals that can be found in drinking water. If the MCL is exceeded, public water supply operators must take steps to ensure the health and safety of the public.

This activity demonstrates factors of dilution for two different substances, one that can be observed by sight and one by smell.

Materials needed:

• Six clear one liter containers
• water
• two medicine droppers
• one milliliter of diesel fuel
• one milliliter of food coloring
• two stirring rods or spoons to stir with

Part one - the food coloring

1. Fill three of the containers with one liter of water.
2. To the first container, add one ml food coloring. (This will be twenty drops from the medicine dropper.)
3. Stir the container, rinse and dry the stirrer.


Now that you have added one ml of coloring to 1 liter of water what is the dilution? (Remember one liter is the same as 1000 milliliters)

4. Take one milliliter (twenty drops) of this solution and add it to the second container.


What is the dilution of the food coloring in the second container? Can you see any trace of color remaining?

5. Take one milliliter (twenty drops) of this solution and add it to the third container.


What is the dilution of the food coloring in the third container? Can you see any trace of color remaining?

Part two - the diesel fuel

6. Fill the three remaining containers with one liter of water.
7. Into the first container put 20 drops (1 milliliter) of diesel fuel using the second medicine dropper. Stir.
8. Then, put 20 drops (1 milliliter) of the diluted diesel fuel solution into the second container and stir.


What is the dilution of the diesel fuel in the second container? Can you smell the fuel?

9. Now, put 20 drops (1 milliliter) of the diluted diesel fuel solution from the second container into the third container and stir.

• Is dilution the solution for contamination?
• At what dilution would you feel safe drinking the water diluted with diesel fuel?
• How would you determine the dilution level that would allow a contaminant to be safe to consume?
• Are the "safe" levels the same for children as they are for adults?
• How can you safely dispose of the water contaminated with diesel fuel?
• What would happen if you disposed of diesel fuel, or other petrochemicals or solvents in a septic system?
• How would you dispose of regular diesel fuel?

1. Do some research about how MCL’s (maximum contaminant levels) are determined, and how safety standards are set. You could discuss the ethics of using animals as test species.
2. Check you local water company’s consumer confidence report. This report details the levels of certain contaminants found in your local drinking water and relates those levels to the federal MCL standards for drinking water.

Goal: To demonstrate how a private septic system works, ways it can be damaged and how it should be maintained.

Background: It has been estimated that approximately 70% of the septic systems in Indiana are not operating effectively. In many instances, the poor operation of a septic system will go undetected for many years. If a system is operating poorly it can be discharging under-treated waste into ditches and streams or into the ground water. Because many systems are not pumped out and inspected regularly, the only time poor operation is noticed is when the system fails completely, and waste water backs up into the residence.

In this activity we build a model of a private septic system, complete with tank and leaching field. To simulate "waste" we used pony beads (can be purchased at any store that sells crafts), smaller beads, glitter, and food coloring. (You may wish to try other things, too.)

Materials:

• a large, transparent, water-proof, container - we used a plastic "sweater storage" box
• some "play sand" - enough to cover the bottom of the container to a depth of an inch or two
• a small clear plastic food storage container, to simulate the septic tank
• modeling clay, the kind that never dries out and is not affected by water
• four, flexible drinking straws
• a small funnel
• water
• some pony beads, smaller beads, and glitter of other materials that can be used to simulate "waste"
• food coloring

Getting started:

Before you begin to build the model you need to prepare some of the materials. (This will be an important safety issue if you are using the model in a classroom situation.)

1. Take three of the straws and using an awl (or an ice pick) poke holes along the length of the straws.
2. Drill or punch a hole into the food storage container in the center of one side near the top. This hole should be just big enough for a soda straw to fit into.
3. Drill or punch a hole into the lid of the food storage container that the small end of the funnel will fit into. This hole should be positioned such that the funnel can be held in place on a long side of the large sweater box, and still fit into the hole.




Now that you have finished using the sharp tools to prepare the materials, you are ready to begin the actual construction itself.

4. Fill the sweater box with one to two inches of play sand. This is the "earth" that will hold the tank and the leaching field for the septic system.
5. Use a small section of straw to connect from the septic tank to where the leach field will be. Seal the joint with modeling clay.
6. Place the septic tank into the sweater box, so that the outlet pipe is lying just on the surface of the sand.
7. Connect the three perforated straws using modeling clay as shown in the illustration, trying to keep the field as level as possible. (It should slope at about a 1% gradient. Water needs a slope to flow, but you don’t want to design the system with such a steep gradient so that all the water rushes to the ends of the pipes. You can have your students calculate what a 1% gradient would be over a given distance for a regular system.
8. Seal the ends of the straws with a little modeling clay.
9. Put a little clay into the bottom of the tank to simulate the sludge that is normally found coating the bottom of the tank. Place some beads into the tank. (The clay will also allow you to keep some of the beads from floating.)
10. Place the funnel over the hole in the tank and seal the connection with modeling clay.


Now the model is built, you are ready to do the simulations.

11. First, slowly add water to the system.


What happens if you add too much water?

12. Add some glitter.


Describe what happens. What do you think the glitter might simulate?

13. Add some food coloring and wash it into the system with a little water.

• solvents
• oils
• hazardous materials
• bleach
• anti-bacterial soaps and detergents

Research your county regulations on septic systems.

For more discussion:

• List some common contaminants in ground water and describe how they could have gotten there.
• You may want to try different slopes on the leaching bed, like 0%, 1%, and 2%. What will happen if the slope is too great?
• List common hazardous materials that could be found around the home.
• Brainstorm about where these would be stored or used in the home (or farm)
• Ask how you should properly disposed of any hazardous material "leftovers"?
• What effect do different types of soils have on the effectiveness of the leaching system?

• Visit some Web pages detailing current and innovative septic systems and discuss the pros and cons of these systems.

Activity 6: The Pucker Effect, Project WET book, p. 338

Surface water and ground water

Because ground water is difficult to observe in the natural environment, the above activities are all based on physical "models." Seeps and springs can be observed on the sides of hills and in ravines in Indiana, and a field trip to observe a spring would be of great benefit to all students.

Ground water and surface water are interrelated. In most areas of Indiana ground water flows into and feeds the streams. The evidence of this phenomenon can be observed in July or August when no rain has fallen in several weeks and there is water continuing to flow in the streams. It can also be observed in winter when the ground is frozen and springs of liquid water flow into the stream beds, or into wetland areas. Simple measurements can be used to back up these observations. Water temperature of streams that have baseflow contributed by ground water will consistently be cooler in the summer and warmer in the winter than the ambient air temperature.

The following activity demonstrates how contaminants can be transferred between surface waters and ground water through natural interactions between the two, or through man made causes, like the pumping of a well.

Activity 7: Aquifer in a pan (any clear container with a fairly large surface area will work) (Adapted from the USEPA)

Goal: To demonstrate some aspects of the interactions between ground water and surface water. To provide a visual tool to show how water is stored in an aquifer, and how drinking water can become contaminated by human activities that occur near the earth’s surface.

Materials needed:

• fish bowl, large plastic storage container, or a baking pan (any clear container with a fairly large surface area will work)
• sand and/or fine gravel - a liter or two
• turkey baster
• square of gauze
• rubber band
• food coloring
• unsweetened powdered drink mix
• spray bottle (mister) of water
• a water source
• paper towels
• medicine dropper
• clay (optional - any kind will work, but be aware that the clay can’t be reused after this activity.)

Procedures: Building the basic model

1. Prepare a simulated well by covering the end of the turkey baster with the square of gauze and securing it with the rubber band. Set aside.
2. Put sand or gravel into the container and shape it into a landscape. Make a pond in part of this landscape.
3. Slowly add water to the container, so that there is a visible "ground water" layer within the sand or gravel and water in the pond.
4. Insert the turkey baster into the landscape for a well.


Working with the basic model:

If you pull some water out with the baster, you are simulating water being pumped out of the ground with a pumping well. In an actual well, the ground water level does not change significantly every time a well pump is activated, because there is a very large reservoir of ground water in most aquifers. In the model you can notice a drop in water level because of the relatively small volume of water in the model and the rather large relative volume of the turkey baster. This phenomenon can be used to demonstrate to the student what can happen when a lot of water is withdrawn from an aquifer that has a small relative capacity. This drop in the water table occurs when withdrawals are greater than recharge.

How is the aquifer recharged?

5. Use the spray bottle of water to simulate rainfall by spraying it on the model.

Variations on the theme

Confining layers

This activity can be expanded to demonstrate how confining layers, like clay layers in the soil, reduce the amount of recharge to the aquifer from infiltrating rain. By adding a clay layer either at the surface or slightly below the surface, the simulated rain will tend to run-off rather than infiltrate. By burying the clay layer below the surface, but above the water table, a spring could be simulated.

Infiltration of contaminants

Unsweetened powdered drink mix can be sprinkled on the top of the model. Spraying the model to simulate rainfall will wash some of the coloring from the drink mix into the ground water. (It works best if this is done near enough to the side of the container that the "plume" is visible through the side.)

Contaminants spilled into pond - Drop some food coloring into the pond then pump water from the well. Did you notice any of the contamination showing up in the well water? Relate this to something that could happen in your community.

References:

Gartrell, Jack E., Jr., et al., Earth: The Water Planet, National Science Teacher’s Association, Arlington, VA 22201-3000, 1992, p. 12.

Andrews, Elaine, et at., Home*A*Syst, An Environmental Risk-Assessment Guide for the Home, WQ-25, Purdue University Cooperative Extension Service, West Lafayette, IN 47907, 1997.

Indiana Science Proficiency Guide, Indiana Department of Education.

Brichford, Sarah, et al., Indiana Farmstead Assessment for Drinking Water Protection, WQ-22, Purdue University Cooperative Extension Service, West Lafayette, IN 47907, 1995.

Nowatzki, John, How Well Is Your Water? Protecting Your Home Groundwater, North Dakota State University Extension Service, Fargo, ND 58105, 1996, pp. 21-26.

Project WET, Water Education for Teachers, Curriculum and Activity Guide, The Watercourse and Council for Environmental Education, 1995.