Last month, the height of the main dam hit 60 feet and with that, the width of the asphalt core decreased from 3.3 feet to 2.95 feet wide. As the dam rises, the water pressure decreases, and therefore, the core does not need to be as thick.  

At the base of the dam, where the asphalt core touches the concrete plinth, the asphalt is 6.6-feet wide for two 9-inch lifts, followed by two lifts placed at 5-feet wide and then continued at 3.3-feet wide. The width will decrease three more times and will be 2-feet wide for the top approximately 160 feet of the 350-foot-tall dam.