I don't know a lot about dams and power plants, but I noticed that this one has no controlled spillway. The top of the concrete wall on the left side of the road is only about 2' above the lake level. The road at it's lowest point is about 3' below the water level. To the right is a massive concrete spillway routing water around the dam and back into the river. So, I'm assuming in a flooding situation that the water just flows over the wall, over the road, and down the spillway. The top of the wall here looks to be a few feet lower in this spot compared to the rest of the dam.