By Kimberly Mullen, CPG
Recommendation
Students should have completed the introductory lesson prior to beginning this activity (so that the vocabulary makes sense to them). Conducting the lessons over a few different classes allows the students to actually learn the vocabulary prior to working on the activities.
Objective
Students will have a clear, working knowledge of aquifers and how they are an important component of the hydrologic cycle.
Background information
An aquifer is a geologic unit saturated with water that can be used as a drinking supply (potable water). The water in an aquifer can be found in sediments and rock. Some rocks are porous and can hold water in the spaces between the grains. Some rocks have a lot of cracks in them, which also allows water to travel through it. Aquifers have different zones: for collecting water, for water entering the ground, and sometimes, for confining water.
Materials
- Container (5 gallon to 10 gallon glass or plastic aquarium)
- Plastic tubing
- Pump from a liquid soap container
- Panty hose, screen, or cheese cloth
- Household sponges
- 5-gallon bucket of sand
- 5-gallon bucket of gravel
- Broken bricks
- Outdoor carpeting
- Modeling clay
- Watering bucket.
Activity
- Divide students into teams of two or three to gather information about the different types of aquifers, the different layers in an aquifer, and the different aquifer zones. (See the recommended list of Web sites below; add to it if needed to allow students to investigate these terms on their own). Students will use this information to create an aquifer model.
- Each student team will chose a specific aquifer type that can be found in the United States. These models should clearly differentiate between aquifer types of substrate and have visible differences between the recharge surfaces and impervious layers. Encourage the student groups to choose from a number of aquifer types so that a number of different types are represented for the class.
- Models need to be created in containers such as a 10-gallon aquarium or smaller clear plastic aquarium.
- Distribute the student handout to assist the students in creating their aquifer model (found below, on the last page of the instructions).
- All models should have these areas built in and marked:
- Water table
- Zone of aeration
- Zone of saturation
- Bedrock
- Water-bearing layer
- Creeks
- Lakes.
The carbonate and sandstone/carbonate aquifers also have:
- Impervious layer
- Confining layer
- Artesian springs
- Sinkhole
- Faults.
Students will continue to add information to the model as they learn about the natural and human systems that rely on the aquifers and waterways specifically found in their county.
- Have students simulate water entering the aquifer contributing and recharge zones in their models. Discuss with students what parts are critical in their models to ensure water enters the aquifer. What features of the model affect the way rainfall gets into the aquifer?
- Be sure that students document every step of the procedure. They should be examining and reexamining choices along the way and updating/changing the model to reflect the learning experience.
- Students should save their models for use in other activities later in the week.
Student information sheet
- What kind of material/materials will be the water-bearing layer?
- Sponge
- Gravel
- Sand
- Bricks.
- How thick will the water-bearing layer be?
- 2 inches
- 5 inches
- 7 inches.
- Will there be a topsoil layer? Choose a material to act as the soil layer.
- Gravel
- Sand
- Outdoor carpeting.
- How thick will the topsoil layer be?
- 1/2-inch
- 1-inch
- 1-and-1/2 inches.
- Will there be a confining layer? Choose a material to act as a confining layer.
- Place the plastic tubing in the container and hold upright as the layers are added. Be sure to cover the bottom of the plastic tube with a piece of panty hose, screen, or cheesecloth. Hold in place with a rubber band. This will prevent gravel or sand from clogging the tube when you pump the water.
- Put the pump in the top hole of the plastic tubing.
- Identify all required features and describe what those features look like in your model:
- Bedrock layer
- Water-bearing layer
- Permeable layer
- Impervious layer
- Contributing zone
- Recharge zone
- Confined zone.
Resource list
The USGS Aquifer Basics Web page:
http://capp.water.usgs.gov/aquiferBasics/index.html
The USGS Ground Water Web page:
http://capp.water.usgs.gov/GIP/gw_gip/index.html.