What Is the Morning Glory Spillway
The morning glory spillway is a funnel-shaped concrete structure at Lake Berryessa in Napa County, California. It is the primary controlled spillway for Monticello Dam, releasing excess water into Putah Creek. The design resembles a giant drain and is one of the most recognizable spillways in the United States.
How the Spillway Works
When lake levels rise above the spillway crest, water flows into the funnel and drops through a large tunnel to the river below. The spillway can pass very high flows, helping protect the dam from overtopping. Operators open the gate only during controlled releases or emergencies.
Safety and Notable Events
The morning glory spillway has been used several times since Monticello Dam was completed in the 1950s. In 1997, a swimmer was caught in the spillway and survived after rescue efforts. Public access to the spillway rim is restricted, and officials warn against entering the water near the structure. Learn more about the dam and its operations at the official Bureau of Reclamation page on Monticello Dam.
