At 22 meters in diameter, the hole sucks in water from the dam to prevent flooding at a rate of 1, cubic meters per second when it reaches capacity, according to Atlas Obscura. The water is carried through a large concrete pipe and emptied about meters away. The hole has been cordoned off for safety reasons since when a woman was pulled in and drowned. During the dry season, when the exit of the spillway is visible, skateboarders have been known to use it as a ramp — although this isn't recommended. Otherwise, boats and swimmers cannot get too close. The Glory Hole was built between and , and wasn't constructed to overspill regularly.
Watch the World's Largest Drain 'The Glory Hole' Empty Water From a Dam
The California floods saw the Oroville dam overflowing , while elsewhere in California excess water became a sight not often seen in this arid part of the western United States. Two years later in February , after a series of storms hit northern California, the epic sight returned to Lake Berryessa. This singular drainage system shaped like a funnel is located in the Monticello Dam, built between and in the Berryessa Valley, in Napa Country. Monticello Dam, with the Morning Glory Hole spillway usbr. Google Maps image of the Glory Hole. The 'Glory Hole' is a concrete spillway shaped like a pipe that looks like the drain of a giant bath tub. Its dimensions leave no room for doubt: the diameter is 22 metres, and water spills over its lip when the reservoir elevation reaches metres.
The spectacular 'Glory Hole' spillway in Monticello Dam, California
A very active glory hole pic by Eric. The Monticello Dam , which holds back Lake Berryessa , features a morning glory spillway. This type of spillway is basically a giant cement funnel.
Monticello Dam is a foot 93 m high concrete arch dam in Napa County, California , United States , constructed between and Lake Berryessa is currently the seventh-largest man-made lake in California. Water from the reservoir primarily supplies agriculture in the Sacramento Valley downstream.