A Man Made Lake

As mentioned earlier, the Lake Berryessa is a man-made lake. And this mysterious spillway was formed at the same time the lake was created. Being the seventh largest artificial lake in California it harbors massive water. That is why this spillway was made. Find out how a hole was helping this giant lake controlling the water inside it.

Prevents Overflow Of Water

The spillway prevents overflow of water in the lake. Additionally, it also did not let water build pressure in the area and around the dam. So, they say the spillway was made years ago but how is it possible that nobody took notice of it before. Well, the answer is here!

Reason

The reason why spillway continued to evade the eyes of people is because of a drought that had clouded California for over a decade. You see, the water level of the lake was all-time low during those years and hence the spillway was left closed. Usually, the spillways are created on the sections of the dam wall or above them. This one was designed differently, giving it a whole new look. 

Why Different?

The water and power operations manager at Solano Irrigation District, Kevin King said, “The bureau has protocol and inspections, and with every inspection, everything has checked out so far,”. This construction and structure (Monticello) are much different than Oroville. We’re very narrow canyon here embedded in bedrock. The traditional spillway construction wouldn’t have fit here. It would have been very costly to drill into the side of the mountains here, so that’s how they came up with the design,” he added.

Bell Mouth

The design of the spillway is called bell-mouth. The other popular name this hole goes by is “glory hole.” It is kind of a funnel popping out of the dam. The hole is 28 feet at the bottom and stretches up to 75 feet in diameter. Now we will learn why the image of a whirlpool occurs when the water reaches a certain level in the lake.

The Behind Story

Whenever the water rises over 440 feet above sea level, it goes over the funnel too. That very moment water begins to drain out of the funnel as it happens in a bathtub, giving an illusion of a whirlpool. Notably, the dam was not much in use for 60 years.