Monticello Dam is located in the Napa Valley of California, heart of the state’s wine producing region. It dammed and impounded the Putah Creek, creating Lake Berryessa, the second largest freshwater lake in California after Clear Lake southeast of Mendocino. Although Lake Tahoe is larger, that lake is within both California and Nevada.
Water from Monticello Dam California primarily supplies the North Bay of San Francisco and other parts of Marin, Sonoma, and Napa counties. The lake was named for the first European settlers who were given the first land grant in the area in 1843—called Rancho Las Putas on Putah Creek. Putah Creek was dammed as early as 1896 with the largest stone bridge west of the Rocky Mountains. It was not until 1953 that construction of the present day Monticello Dam began. The entire town of Monticello was inundated. Its cemetery was moved to Spanish Flat, a nearby bluff.
The creation of Lake Berryessa by Monticello Dam allowed the development of one of the most popular recreational resort areas in the United States, comparable to the Lake Cumberland formed by the Wolf Creek Dam in Kentucky and Lake Mead, the largest such reservoir in the United States. The most apparent signs of tourism here are found on the lake itself in the form of houseboat rentals, jet skiing, and water skiing. Fishing (for trout, bass, catfish, crappie, and bluegill) is also popular, as is camping.
Around the Monticello Dam California itself, you will find an array of bird sightings, including geese, pelicans, grebes, ducks, loons, and great blue herons. There are several marinas around the lake’s shores. The Cedars Roughs Wilderness on the eastern part of the lake is just what its name suggests—virtually undisturbed wilderness boasting mountain lions, deer, osprey and golden eagle, as well as rattlesnakes. When you’re tired of pristine wilderness, you can head to the sophistication of the nearby Napa Valley wineries, spas, and luxurious bed and breakfasts.
The Monticello Dam California boasts the “morning glory” Monticello Dam Drain Hole that is the largest such uncontrolled spillway in the world. We have all seen drain holes as we empty our bathtubs. These spillways are used in most dams to keep the level of the reservoirs at a regulated depth. There are several kinds. The Monticello Dam Drain Hole is uncontrolled, meaning it has no gates. Reservoir water drains out of it whenever the level rises over the spillway lip. At its widest, it has a diameter of 72 feet. It has a horizontal exit that skateboarders and cyclists use as a half-pipe when the lake’s level is low. When the lake level is high, ropes and buoys keep swimmers away as it can be dangerous. Like other uncontrolled spillways, the Monticello Dam Drain Hole resembles the open flower of the morning glory. It is also called a bellmouth spillway.
The Glen Canyon Dam and Hoover Dam in the United States have similar drain holes, as does the massive Three Gorges Dam on the Yangtze River in China. There is even one in the Upper Basin at Yellowstone National Park in Wyoming. This is called the Morning Glory Pool, and is the naturally occurring drain hole of a hot springs.