A man solved the mystery of the gaping hole inside a lake in California!

Draught Brought Cause

A decade-long drought meant that there was less than normal water in the lake, let alone water overflow which meant that the spillway had no purpose left. The water levels were all-time low and so the spillway was closed because of its lack of use. Mostly, the spillways go through sections of the dam wall or are over them. The design of the spillway in Lake Berryessa was different, making it appear like a hole in the river.