Grades : middle and upper
Objective: to illustrate the movement of groundwater through soils
Subjects: Earth Science, Social Studies, Health
Materials : 2 liter clear plastic containers, pump sprayers from a bottle of all purpose cleaner, small pieces of nylon fabric, masking tape or rubber bands, scissors, transparent straws, small rocks, clean sand, food coloring, spray container with water, disposable water syringe.
Information:
“It is not until the well runs dry, that we know the worth of water.” Benjamin
Franklin
It is said that at any given time, the world’s streams contain more than 300 cubic miles of water. The volume of the world’s fresh-water lakes is one hundred times that with nearly 30,0000 cubic miles of water. Even this amount pales in comparison to the amount in the world’s groundwater which is estimated to be 1,000,000 cubic miles of water. However, only a fraction of this underground reservoir can be actually tapped and made available to us on a perennial basis through wells and springs. (U.W.
Geological Survey) These are important points when you consider the fact that up to
80% of the Catskill Watersheds’ residents use groundwater for their water supplies.
(NYC DEP)
This flow model will help students visualize the movement of water through the ground recording the processes of tapping an underground reservoir and the effects of contamination of these resources.
Procedures:
1. Begin by having groups of students follow the directions for making a flow model.
A. Secure a piece of nylon over the end of the pump sprayer with masking tape or a rubber band. The nylon will act as a pump screen.
B. Cut the top off a plastic 2 liter container.
C. Fill the container approximately one-third full with small rocks.
D. Insert the pump sprayer into the rocks and hold it vertically near the side of the bottle while filling the container with

sand to within two inches from the top.
E. Insert a straw into the sand near the outside of the container opposite the pump sprayer.
2. Add water slowly to the containers to saturate the sand and rocks. Observe the water table in each and discuss how the addition of precipitation affects the level of a water table. The sprayers represent wells which will be operated to utilize the groundwater.
3. Use the pump sprayer to withdraw water from the flow model. During pumping, observe the dip in water level around the well. This is known as the cone of depression. It will gradually fill back in with water after the pumping stops.
Observe and record how the well is able to affect the level of the water table.
4. Draw the water level below the surface of the sand. Spill some “pollutant” (food coloring) on the top of the sand. Use the well pump to withdraw water from the model and observe any movement in the pollutant.
5. Spray water on the sand to simulate rain and draw water from the model with the pump. Observe and record the difference in the action of the pollutant when the chemical comes in contact with the water.
6. Next, add food coloring into the straw using a syringe of water and inject the pollutant into the top layer of water in the sand. Use the well pump to withdraw water from the mode and observe and record the movement of this pollutant through the groundwater.
7. Take this opportunity to discuss the dynamics of aquifers and the process and time necessary to clean any contaminated underground waters.

Investigate how different soils influence the rate of groundwater flow by replacing the sand and rocks in the flow model with clay or other types of soil.

Discover how much water different materials will hold by performing the following experiment. Begin with several containers holding the same amounts of different soil materials. Pour known quantities of water into each of the materials measuring the amounts of soils are able to absorb. This experiment will help students discover the soils beneficial for groundwater supplies. For example, sand is ideal to get groundwater from because it holds water more than gravel, and also allows the water to flow faster than in clay.

Further explore how water runoff from urban or rural communities can affect groundwater and well use by adding this set up to the landform models in this guide’s activity The Lay of the Land.
:


Name something in your community that may contaminate your groundwater supplies (i.e. landfills, storm drain runoff).

What would a community do if their groundwater became undrinkable? To find out what New York City did when it was in that situation, see From Wells to watersheds.
: Adapted from Groundwater Flow Model – 2 Liter in A Hidden Treasure