Water Table

By Mary Lou Alfieri

Background:

The water table is the surface between the zone of saturation and the zone of aeration. The water table moves up and down in response to variations in the amounts of water making it down to the water table. Depending on the position of the water table and the topography of the surface, a variety of water features can be produced at the surface. These features include lakes, wetlands, rivers and streams. The water level in these features then become directly related to fluctuations in the level of the water table.

Objective:

Become familiar with the term water table. Recognize the water table as one of the contributing factors in the existence of streams, swamps, and lakes in Nebraska.

Materials:

  • Wide mouth jar
  • sand and gravel
  • water
  • food coloring
  • glass
  • marking pen, paper and pencils

 Procedure:

  1. Using a sand and gravel mix, fill the wide mouth jar 3/4 of the way full.
  2. Fill the glass with water and slowly pour the water into the jar. Tilt the jar as you pour in the water and allow the water to rise 1/2 way up the jar.
  3. Use a marking pen and mark the top of the water level on your jar. This line represents the water table. Draw a sketch of your setup. Label the water table.
  4. Add more water to the jar. Note how this effects the level of the water table.
  5. Add 10 drops of food coloring to the side of your jar. Observe what happens to the flow. Record your observations.

Conclusion:

  1. In dry weather periods what happens to the level of the water table? How will this effect water features on the surface feed by this water?
  2. What did the colored water represent in the experiment? How does this relate to what happens in the real world environment?
  3. What is the source for water that is in the groundwater system?
  4. Describe how the level of a groundwater fed lake can fluctuate.
  5. Ona diagram of the hydrologic cycle, label the following:
    1. precipitation
    2. run-off
    3. infiltration
    4. zone of aeration
    5. zone of saturation
    6. water table

Notes about the hydrologic cycle:

Teachers: After you print the hydrologic cycle, you will want to "white-out" the answers before you distribute to your students.

Credit: This diagram was scanned from the Fundamentals of Groundwater Contamination, Educational Circular Number 11, Conservation and Survey Division, by Darryll T. Pederson.