It belongs to a vertical funnel spillway, with a spillway mouth width of 2 1.9m and a depth of more than 61m.. When the water level of the lake is higher than the warning line, the excess water will flow into the overflow tunnel and flow out from the channel at the bottom of the dam. When the water level is high, about 7570 cubic meters of water will flow into this huge hole every minute, which will never be filled.
Lake Belier, located in Napa County, California, USA, is the largest lake in Napa County. Lake Bayesa is formed by storing water from the Monticello Dam built in 1950s, which is used for regulating water quantity, hydroelectric power generation and other functions. When the water level is full, the area of the lake reaches 80 square kilometers.