We took a guided tour of the Fort Peck Dam power plant today. There are two power plants, with three massive turbine generators in each plant. We were shown where the water enters the turbines from the Missouri River. The water is diverted from the river through 24-foot diameter tunnels, one-mile long. The tunnels are constructed with 24-foot diameter steel tubes encased in concrete. There are four of these tunnels buried 300 feet beneath the dam. Two of the tunnels feed water to the turbines in the two power plants. The other two tunnels are used to divert water from the lake for flood control. This was an unexpected and pleasant discovery during our first camping stop on our way to Montana.