page_title: Monticello Dam
section_title: Spillway
hierarchical_section_title: Monticello Dam / Spillway
caption_attribution_description: English: A view of the Monticello Dam "glory hole" on Saturday, October 10, 2009. The crest of the spillway is at 439.96 feet (134.10 m). In this picture, the water level is at 407.72 feet (124.27 m), or 32.24 feet (9.83 m) below the crest.
context_page_description: Monticello Dam is a 304-foot high concrete arch dam in Napa County, California, United States constructed between 1953 and 1957. The dam impounded Putah Creek to create Lake Berryessa in the Vaca Mountains.
  Lake Berryessa is currently the seventh largest man-made lake in California. Water from the reservoir primarily supplies agriculture in the Sacramento Valley downstream. The dam is noted for its classic, uncontrolled morning-glory-type spillway. The diameter at the lip is 72 ft. Locally, the spillway is also known as the "Glory Hole".
  To the south is Putah Creek State Wildlife Area.
context_section_description: The dam's morning-glory-type spillway, known as the Glory Hole, is 72 feet (22 m) in diameter at lake level and narrows down to about 28 feet (8.5 m) at the exit. At the lake's peak level, the spillway can drain 48,400 cubic feet per second (1,370 m³/s), which occurs when the lake level rises to 15.5 feet (4.7 m) above the level of the funnel.
  Water spills over its lip when the lake reaches 1,602,000 acre feet (1.976×10⁹ m³) and a reservoir elevation of 440 feet (130 m) above sea level. The last time the reservoir naturally spilled through the glory hole was on the afternoon of February 26, 2019.
  Prior to that, the last time the spillway was active was February 16, 2017. After a number of storms had caused the lake level to rise 35.5 inches since January 1, 2017, the reservoir was on the cusp of spilling once again at 439.2 feet. Eager to witness this event, a number of local boaters and recreation enthusiasts generated enough wake to cause the reservoir to spill, albeit briefly, at 1:45 p.m. on February 13, 2017. Lake Berryessa reservoir filled and ran into its glory hole spillway for the first time in over a decade on February 16, 2017, at approximately 3:00 p.m. PST .
  Current lake level status is available at Solano County Water Agency.
  Swimming near the Glory Hole is prohibited. The only known case of death from the spillway drain occurred in 1997. Emily Schwalen of Davis died after being caught in the current while swimming near the Glory Hole and being swept down the pipe after holding on to the rim for about 20 minutes.
caption: Spillway on October 10, 2009 when the water was 32.24 feet (9.83 m) below the crest.
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