Isabella Dam is an embankment dam located in the Kern River Valley, about halfway down the Kern River course, between the towns of Kernville and Lake Isabella in Kern County, California.
Isabella Dam serves agricultural, hydroelectric, and flood control uses. Lake Isabella (the reservoir created by the dam) also serves as a recreational and tourist attraction. Water sports, fishing, boating, camping, and hiking are common throughout the area, as well as the Sequoia National Forest.
Background
The town of Isabella was founded by Steven Barton in 1893 and named in honor of Queen Isabella of Spain while her name was popular during the 1893 Columbian Exposition. In 1948, Congress appropriated funds to build a dam to prevent flooding of Bakersfield. The city had been flooded in 1867 and 1893. In 1950, while the dam was under construction, they experienced flooding measuring of water per second. The dam was completed in March 1953. The U.S. Corps of Engineers built earthen dams across two forks of the Kern River to create the Isabella reservoir, Kern County's largest body of water year round with a surface area of . During the construction of the dam and reservoir the towns of Lake Isabella and Kernville both had to be moved to higher ground. Most of the original town of Kernville had been razed in 1948, in preparation for the construction of the dam.
Below Isabella Dam, the Kern River flows southwest through approximately of a canyon, locally known as Kern Canyon, with many steep cliffs and turns along the southern edge of the Greenhorn Mountains, roughly east of Bakersfield. Once it reaches Bakersfield, the river loses most of its remaining flow; much of it is diverted and channelized before reaching the city center.
Bakersfield and about of farm land and oil fields in the Kern River region are protected by the project. As a partner to dams on the Kings, Kaweah and Tule Rivers, the Isabella dam helps curb flood losses to cropland in the Tulare Lake Basin as well.
Construction and operation
Bakersfield sustained extensive damage by being seventeen feet below the flood crest of the 1937 flood of the San Joaquin River Basin. During 1943, some $10 million ($137 million today) worth of flood damage was done to agriculture alone in the Tulare Lake Basin; the Kern River contributed almost half of the flow that caused the damage. The Sacramento District, under the direction of the district engineer, Lt. Col. Chambers, and by the authority of the 1936 Act, conducted a study of the area in 1937. Their study, completed in 1940, disclosed that roughly $750,000 (over $12 million today) in flood control benefits would be realized with the completion of regulatory works on the Kern River. Their study also showed that an average benefit to irrigation and existing power facilities of $185,000 ($2.5 million today) could be gained as well. After the District filed its report, Congress authorized the Isabella Project in the 1944 Flood Control Act. Construction began in 1948, under contract with Rand Construction Company, and completed in 1953; the federal government spent $22 million ($305 million today) for the project.
Isabella Dam consists of two dams, a "main dam", and an "auxiliary dam". The main dam is of earthen build, long and tall, and owned and maintained by the U.S. Army Corps of Engineers. The main reservoir, Lake Isabella, can hold up of water. Normal release from the main dam is , maximum historical releases were in 1983.
The reservoir that Isabella Dam creates is called Lake Isabella. Water from Lake Isabella can be used in any of three ways. It is released into the Lower Kern River from the main dam, through the hydroelectric project in the main dam, or through the hydroelectric project in the auxiliary dam. The design capacity of the release channel (the Lower Kern River) is over . If Lake Isabella is above , the water can also be diverted into the Borel project at the main dam.
Borel Hydroelectric Project
Hydroelectric development on the Kern River in central California began in 1894 when the Power, Transit and Light Company started construction of a small plant at the mouth of Kern Canyon. The following year, the Kern River and Los Angeles Electric Power Company obtained water rights on the river and planned construction of a power plant. This project, Borel Hydroelectric Project, was built to provide power for the growing Red Electric Streetcar (also known as Red Car) transportation system in Los Angeles.