The Khun Dan Prakan Chon Dam Museum is a pleasant attraction that tells all you might want to know about the dam in both Thai and English. It includes the history behind the need for the dam and all the technical specifications of its construction.
What is also nice is the museum includes a lot of background information on Nakhon Nayok's history, geology and geography. There is also an excellent section on the history of mankind's water management projects from the ancient Egyptians all the way forward to some of the greatest modern day dams around the world.
The museum is generally only open at the weekends and the entrance fee is a mere 20-baht.
The museum is located in front of the Khun Dan Prakan Chon Dam. When you reach the traffic circle with the elephant fountain in the middle you turn right and the museum is immediately on your left.