The Seminoe Dam and Power Plant are on the North Platte River about 72 miles southwest of Casper, Wyoming. Seminoe Reservoir, with a total capacity of 1,017,280 acre-feet, provides storage capacity for the water to irrigate the project lands. The power plant generates electric power as the water is released for irrigation or stored in Pathfinder Reservoir for later release as required.
The dam is a concrete-arch structure containing 210,000 cubic yards of concrete and rising 295 feet above the rock foundation. Water is released from the reservoir through penstocks to the Seminoe Power Plant, or over a controlled spillway and outlet tunnel. The power plant is located at the base of the dam, and has a rated head of 166 feet. The plant contains three units, each composed of a 13,500-kilowatt generator driven by a 20,800-horsepower turbine.
Foundation: Hard granite cut by close joints, generally tight but locally open, with two intersecting major faults under the dam