Abstract: A system for extracting power from the tides includes a dam constructed in a body of water subject to tidal flow for separating the body of water from a tidal basin between the dam and the shoreline. A plurality of water wheel assemblies are mounted on the dam and include mounting saddles for mounting water wheels for rotation about a horizontal axis at a level about the high tide level of the body of water and with the bottom of the water wheel at substantially the low tide level of the body of water. Each saddle includes a pair of vertical wall members, between which the water wheel is mounted for rotation, and a horizontal wall portion below the water wheel provided with a concave recess receiving the water wheel. The saddle is so constructed that substantially all of the water flowing from the body of water to the tidal reservoir and vice versa will flow through the water wheels. In order to control this flow, a brake is provided to block rotation of the water wheels at the discretion of an operator.