The world’s first tidal dam was built in La Rance, France, in 1966. The power plant on this dam near the Rance estuary can produce up to 240 megawatts of electricity. This dam uses tidal energy, which is variable and based on the flow of high and low tide.

The power plant on Hoover Dam in the Colorado River can produce almost 10 times the electricity of La Rance tidal dam. It generates power from the release of water from Lake Mead near Las Vegas, Nevada.

Research pictures of La Rance tidal dam and the Hoover Dam. Pick one and draw an illustration of the dam, including what you think it might look like under the surface of the water. (Hint: Think about how fish and other water creatures might be affected by each of these dams.)

With a partner, brainstorm some ways people can reduce the impacts of dams on fish and wildlife. Write one of your ideas here: