Somewhere between 655,000 and 758,000 years ago, California’s Central Valley was covered by a shallow body of water known as Lake Corcoran. Lake Corcoran covered the valley from what are now the Tehachapi Mountains to the Sierra Buttes and at its greatest extent was as large as Lake Michigan is today. It drained into the Pacific through what is now the Salinas River and Monterey Bay. It is hypothesized that Lake Corcoran provided much of the water for precipitation in the Sierra Nevada through evaporation and that water partially formed several pluvial lakes in Nevada. Wildlife flourished and fossil remains of the short-faced bear, mammoth, dire wolf, giant sloth, early horses, camels, and antelopes have been found in the Central Valley.
This vast freshwater inland sea was not to last. Some 650,000 years ago, the Earth began to warm and the glaciers which held the Sierra Nevada in an icy grip began to melt. The water began to rush into the lake raising the water level. At the same time, tectonic uplifting of the Coast Range near Monterey left Lake Corcoran with no outlet to the sea. Something had to give and it did. Approximately 600,000 years ago, Lake Corcran carved a new outlet to the sea through what is now Carquinez Strait. The water poured through a low spot in the Coast Range carving a channel 100 feet deep between what are now Contra Costa and Solano counties and permanently draining Lake Corcoran and changing the landscape of the San Francisco Bay Area and the Central Valley forever.
Lake Corcoran didn’t completely disappear. Kern, Buena Vista, and Tulare lakes were all remnants of the former freshwater inland sea. In fact, up until the late 19th century, the Central Valley was prone to flooding which turned the land into a vast swamp. During the Spanish and Mexican periods, maps labelled the valley as “Cienega de Tulares” or “Marsh of the Tules”. While the Spanish and others saw the Central Valley as a marshy place with little to no value, the indigenous people who lived there thought very differently. The entire valley teemed with wildlife and the wetlands provided fish and fowl. Elk, deer, and beaver were plentiful. The plentiful tules provided the raw material for houses, baskets, clothing, and boats. The largest of the three lakes, Tulare Lake or Pa’ashi as it was known to the local Tachi people was the largest fresh water lake west of the Mississippi and the ninth largest in what would be the United States.
In the mid to late 1800’s many people drained and diverted the water from the marshy areas of the Central Valley to create farm and ranch land. By 1899 Tulare Lake went dry due to diversion of its source water for flood control and agricultural purposes. Buena Vista Lake lasted as an agricultural reservoir and recreational lake until 1953 when the Lake Isabella dam was built across the Kern River creating Lake Isabella. That isn’t to say that the former lakes remained dry. In the years in which there are large amounts of precipitation, most recently in 2022-23, the Tulare Lake basin has been partially refilled allowing the lake to be “reborn” and give today’s Californians a glimpse of what the Central Valley and the Tulare Lake Basin looked like in the past.
More Information: The prehistoric and historic past of the Central Valley is one of change and of human interaction and intervention which has had a direct and profound impact on the geography, history, and economy of California as a whole. Luckily, there are a few institutions who have attempted to preserve the unique history of the Central Valley.
Sarah A. Mooney Museum
542 W “D” Street
Lemoore, CA 93245
Hours: 12 to 3 p.m. on Sundays (closed on major holidays.)
The Sarah A. Mooney Museum is a preserved Victorian house with exhibits highlighting how a well off family lived in the area during the Victorian Era.
Buena Vista Museum of Natural History and Science
2018 Chester Avenue
Bakersfield, CA 93301
Hours: Thursday-Saturday: 10am-4pm, Sunday: 12p-4pm, Monday-Wednesday: Closed
Admission: Members: Free, Children 2 and under: Free, Adults: $10, Seniors (60+): $8
Students 12 years and older: $8, Children (3-11): $6. The Museum also has special admission days. Please visit its website @ https://www.buenavistamuseum.org/hours-and-admission
The Buena Vista Museum of Natural History and Science has exhibits about the Central Valley during the Miocene Epoch and Indigenous American life as well as exhibits on Paleontology and other areas of Science.
Kern County Museum
3801 Chester Ave, Bakersfield,
Hours: Monday & Tuesday: Closed, Wednesday – Sunday 9:00 am – 4:00 pm
Closed ALL Federal Holidays.
Admission: Adults: $10.00, Seniors/Military: $9.00 Children: – ages 3 to 12: $5.00 – ages 2 and under FREE when accompanied by an adult. Members: FREE
Free admission to Active Duty Military and their immediate families from Memorial to Labor Day. Please visit the Kern County Museum’s Website @ https://kerncountymuseum.org/ for more information.
The Kern County has many exhibits covering the general history of Kern County including indigenous peoples, the ranching, farming, oil, and music industries. One of the museum’s highlights is the childhood home of Merle Haggard.