Oroville << OHR uh vihl >> Dam is the highest dam in the United States. It rises 770 feet (235 meters) and extends 6,800 feet (2,073 meters) across the Feather River, near Oroville, California. The Oroville Dam is the chief dam of the State Water Project, which supplies irrigation water to central and southern California.
The dam is an earth-fill dam (see Dam (Embankment dams) ). About 80 million cubic yards (61 million cubic meters) of earth materials were used in its construction. It was completed in 1968. The materials came from waste piles at nearby gold mining operations.
The Oroville Dam forms a reservoir called Lake Oroville, which contains about 31/2 million acre-feet (4.3 billion cubic meters) of water. Water from Lake Oroville is used to irrigate farmland as far as 650 miles (1,050 kilometers) away in southern California. A hydroelectric power plant connected to the dam also uses the water. The dam also helps control floods.
In early 2017, heavy rains forced water over the Oroville Dam’s main spillway, a passage that releases excess waters that the reservoir cannot contain. The rapidly flowing water damaged the main spillway, forcing engineers to reroute water to the emergency spillway. Officials feared that erosion might cause the emergency spillway to release too much water, causing catastrophic flooding. They ordered the evacuation of about 188,000 people from nearby areas. Repairs to the main spillway were completed in late 2018.
