My family and I unfortunately never got to see the dam. We drove half an hour from where we were staying, sat in traffic actually on of the property and got stuck there for maybe another 30 minutes as we had to follow everyone past the full parking lot and down to the bottom of the path to turn around and exit the grounds. There was absolutely no way to turn around otherwise.
It was an incredibly disappointing experience and appears to me that an extra lot set up off grounds with a shuttle could really help with the traffic and overflow of visitors. The whole place is a desert. There's a ton of land you can build parking on.
If you plan on visiting with your family, I highly suggest you go before the site even opens up and sort of wait around the area or park in line to enter. Attempting to go at noon is going to eat up a lot of your day if you get stuck in the pathway and never get a parking spot.