Too Narrow
As mentioned, Lake Berryessa was a very long, very narrow lake. When engineers considered the options for a spillway, they saw no way to place it right in the wall of the dam. The spillway was required to be very large, and finding a way to incorporate it into the mountainside was near impossible. Not to mention, it would have cost way too much to complete! Instead, the engineers came up with another option that would be easier and more affordable.
Another Option
A Foolproof Plan
The dam had to work perfectly; the water needed to always remain between a certain level, and it always had to be flowing properly. When it was working at its highest efficiency, the water would easily make its way into the nearby creek called Putah Creek. In addition, the natural flow would also provide all of the electricity and water to nearby cities. All this being said, the design of the dam had to be perfect.
The Perfect Design
