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Build a Dam

Beavers build dams to flood out streams and create safe habitats for their families. Dams block streams or rivers to create a calm pond deep enough for the beavers to build a lodge. Design and build a dam, then add water to one side to test your dam. You can build your dam in a paint tray or head outside to a sandbox or beach instead. Try different materials to find out what works best to keep the water on the upper side of your dam.

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  • Do you want to do this adventure inside, outside or at camp? Do you have access to a sandbox or beach you could use instead of the paint tray?
  • What do you know about beaver dams?
  • Why do beavers build dams?
  • What materials will you use to build your dam?
  • Do you want to do this adventure alone or in small groups? How will you make your groups?
  • Where will you get water to test your dam?


  • Build a dam across the middle of the container.
  • Test your dam by pouring water on one side. Does any water make it through?
  • Tweak your dam until it keeps all of the water on one side of the container.
  • For an extra challenge, try building a dam without any glue.


  • What do you know now that you did not know before?
  • What materials worked best? What didn’t work so well?
  • How does your dam compare to a real beaver dam?
  • What do you think would happen to your dam if the water was flowing instead of sitting still?
  • What elements of STEM were in this adventure? Science? Technology? Engineering? Mathematics?
  • What did you like about this adventure? What did you not like? How would you do this adventure differently?
  • Remember to submit your activities on our Scouts for Sustainability Take Action Map


  • 1 paint tray per Beaver Scout or group
  • Plasticine
  • Popsicle sticks
  • Toothpicks
  • Straws
  • Twigs
  • Leaves
  • Access to water

Keep it Simple

  • Rather than building a dam, try drawing a beaver lodge. What would you want the inside of your lodge to look like?
  • Some Beavers might find it easier to work in groups, and that’s ok too! Work in small groups to build your dam. 

Take it Further

  • Try building another animal’s home. Try a wolf den, bear den or a nest.