Lake Oroville

Oroville Dam is an earthfill embankment dam on the Feather River east of the city of Oroville, California, in the Sierra Nevada foothills east of the Sacramento Valley. At 770 feet (235 m) high, it is the tallest dam in the U.S. and serves mainly for water supply, hydroelectricity generation, and flood control. The dam impounds Lake Oroville, the second-largest reservoir in California, capable of storing more than 3.5 million acre-feet (1.1×10^12 US gal; 4.3×109 m3).Built by the California Department of Water Resources, Oroville Dam is one of the key features of the California State Water Project (SWP), one of two major projects passed that set up California's statewide water system. Construction was initiated in 1961, and despite numerous difficulties encountered during its construction, including multiple floods and a major train wreck on the rail line used to transport materials to the dam site, the embankment was topped out in 1967 and the entire project was ready for use in 1968. The dam began to generate electricity shortly afterwards with completion of the Edward Hyatt Power Plant, then the country's largest underground power station. Since its completion in 1968, the Oroville Dam has allocated the flow of the Feather River from the Sacramento-San Joaquin Delta into the SWP's California Aqueduct, which provides a major supply of water for irrigation in the San Joaquin Valley, as well as municipal and industrial water supplies to coastal Southern California, and has prevented large amounts of flood damage to the area—more than $1.3 billion between 1987 and 1999. The dam stops fish migration up the Feather River and the controlled flow of the river; as a result, the Oroville Dam has affected riparian habitat. Multiple attempts at trying to counter the dam's impacts on fish migration have included the construction of a salmon/steelhead fish hatchery on the river, which began shortly after the dam was completed. In February 2017, the main and emergency spillways threatened to fail, leading to the evacuation of 188,000 people living near the dam. After deterioration of the main spillway largely stabilized and the water level of the dam's reservoir dropped below the top of the emergency spillway, the evacuation order was lifted.The main spillway was reconstructed by November 1, 2018, and water releases were successfully tested, up to 25,000 cu ft/s (710 m3/s), during April 2019.

In February 2017, heavy rainfall damaged Oroville Dam's main and emergency spillways, prompting the evacuation of more than 180,000 people living downstream along the Feather River and the relocation of a fish hatchery. Heavy rainfall during the 2017 California floods damaged the main spillway on February 7, so the California Department of Water Resources stopped the spillway flow to assess the damage and contemplate its next steps. The rain eventually raised the lake level until it flowed over the emergency spillway, even after the damaged main spillway was reopened. As water flowed over the emergency spillway, headward erosion threatened to undermine and collapse the concrete weir, which could have sent a 30-foot (10 m) wall of water into the Feather River below and flooded communities downstream. No collapse occurred, but the water further damaged the main spillway and eroded the bare slope of the emergency spillway.

Kelly Ridge is a census-designated place in Butte County, northern California.

Oroville East or Kelly Ridge is a census-designated place (CDP) in Butte County, California, United States. The population was 8,280 at the 2010 census, down from 8,680 at the 2000 census. Most citizens are dependent on the commerce of Oroville, and the vast majority of high school students in Kelly Ridge (Oroville East) attend Las Plumas High School. The community of Kelly Ridge sits at Lake Oroville and offers direct access to boating, camping, fishing and a variety of water sports.

The Mother Orange Tree is the oldest living orange tree in Northern California. The California Historical Landmark is located at 400 Glen Drive in Oroville, California.

Lake Oroville State Recreation Area (LOSRA) is a state park unit of California, United States, surrounding Lake Oroville, a reservoir on the Feather River. It is located in Butte County outside Oroville, California. The 29,447-acre (11,917 ha) park was established in 1967. The recreation area "includes Lake Oroville and the surrounding lands and facilities within the project area as well as the land and waters in and around the Diversion Pool and Thermalito Forebay, downstream of Oroville Dam."

Bidwell's Bar (also known as Bidwell Bar, and Bidwells Bar) was a gold mining camp in Butte County, California, United States, which lay at the end of the California Trail. It was located 6.5 miles (10.5 km) east-northeast of Oroville, at an elevation of 902 feet (275 m).

Oroville Hospital provides health coverage to the City of Oroville. It is the main hospital for the city of Oroville, California. The building is the City of Oroville in Butte County. It is also a Level III trauma care center. The hospital was founded in 1962 and has grown from a modest community hospital supported by a small staff of doctors into a 133-bed acute care facility specializing in a broad range of inpatient and outpatient services, including multiple physician practices. Oroville Hospital is a private, non-profit corporation serving the Oroville area and Butte County by OroHealth Corporation.

Oroville High School is a public high school located in the rural north valley at the base of the Sierra Nevada foothills, about seventy miles north of Sacramento, California, United States. Founded in 1892, Oroville High School is the oldest high school in the district. The campus covers 4 acres (16,000 m2). Of the 46 classrooms on campus, five have full functioning computer labs. The campus also has two computer labs and a library. In 2003, a school bond for $8,523,932 was passed, allowing for the construction of a new library, a science wing, and an industrial technology center. These funds were intended to convert older buildings on campus to an art building, a center for performing arts, and a more modern gymnasium. Despite the money set aside, all of these projects were shelved due to the extreme financial situation of the school district.

The Koppers Co., Inc. (KCI) Superfund Site is one of three Superfund sites in Oroville, California, along with Louisiana Pacific Sawmill and Western Pacific Railyard. The KCI Superfund Site is a 200-acre site which served as a wood treatment plant for 50 years. Wood was treated with many chemicals to prevent wood deterioration. The accumulation of these chemicals from spills, fires, and uses has caused this site to be contaminated with the hazardous waste material. Due to soil and groundwater contamination, the site was placed on the National Priorities List in 1984 for remedial action plans to clean up the site to protect surrounding residential areas concerning environmental and human health risks.

Oroville (Oro, Spanish for "Gold" and Ville, French for "town") is the county seat of Butte County, California, United States. The population of the city was 15,506 at the 2010 census, up from 13,004 in the 2000 census. Following the 2018 Camp Fire that destroyed much of the town of Paradise, the population of Oroville increased as many people who lost their homes relocated to nearby Oroville. In 2020, the 2020 census recorded the population of Oroville at 20,042. Oroville is considered the gateway to Lake Oroville and Feather River recreational areas. The Berry Creek Rancheria of Maidu Indians of California is headquartered in Oroville.Oroville is located adjacent to State Route 70, and is in close proximity to State Route 99, which connects Butte County with Interstate 5. The city of Chico is located about 23 miles (38 kilometers) northwest of the city, and the state capital of Sacramento lies around 70 miles (112 kilometers) to the south.Oroville's nickname is the "City of Gold", which is essentially the Spanish name of the city in English. Oroville has also been declared a Tree City USA for 41 years by the National Arbor Day Foundation.

Oregon City, formerly Bloomingdale and Hengy, is a ghost town located between Oroville and Cherokee in Butte County, California. One of the first mining camps in the county, it was established in the autumn of 1848 by a party of Oregonians, who came to California over the Applegate and Lassen trails. Little more than a year later their captain, Peter H. Burnett, became the first civil Governor of California. For a time, Oregon City prospered as a gold mining and supply center, then it declined into virtual oblivion. It lies 1,184 feet (361 m) above mean sea level. The Hengy post office operated from 1894 to 1900 and from 1901 to 1902; it was named after the first postmaster, Jessie Hengy. The Bloomingdale post office operated from 1902 to 1905.The site of the camp is now a California Historical Landmark.The Oregon City Covered Bridge, also known as the Castleberry Covered Bridge, is located near Oregon City.