1976: The groundwork for the dam that will form the cooling lake for Illinois Power Co.'s nuclear power plant is being laid. A concrete spillway that will help regulate the height of the leak is in the center, foreground. The edge of the spillway, at left, will stand at 690.5 feet above sea level and water higher than that level will splash over the top, lead down the concrete and into Salt Creek. The arrow pointing to the east also shows the direction in which the dame will be built. Workers currently are placing a special fill dirt into the base of what will be the earthen dam. Work will soon begin on another spillway, further east, outside the photograph, that will handle waters above the 700-foot mark. Lake Clinton will form north of the spillways, taking the water of Salt Creek and North Fork of Salt Creek. The North Fork currently is being diverted around the construction site. Illinois 10 is south of the dam site, outside the photo. The dam is expected to be completed in September, 199, and the lake filled approximately two years later.