Central Valley (California)

Home to a Huge Number of California's Productive Agricultural Enterprises

12/31/2010. The valley in central California, is big and, flat and is situated in the dominate portion of central California. It's home to a huge number of California's highest productive agricultural enterprises. it's a long valley which runs for about 400 miles from the north to the south. The Northern half is commonly called the Sacramento Valley, and the southern half is labeled the San Joaquin Valley. Rainfall in the Sacramento valley is about 20 inches, however the San Joaquin Valley is especially dry, even turning to desert in some parts. The two halves convene at the delta they share where the San Joaquin and Sacramento Rivers converge. The delta is a huge expanse of marshes, streambeds, sloughs, interconnected canals, and islands of peat soil. The area of the Central Valley encompasses about 42,000 square miles, which makes it somewhat in size to the state of Tennessee. 

Population and Boundaries

Constrained by the Cascade Mountain Range on the north, Sierra Nevada Mountains on the east, Tehachapi Mountains on the south, San Francisco Bay and Coast Ranges and on the west, the central valley is an enormous agricultural region drained by the San Joaquin and Sacramento rivers.

Counties commonly associated:

  • North Sacramento Valley (Colusa, Butte, Shasta, Glenn, Tehama)
  • Sacramento Metro (Sacramento, Placer, El Dorado, Yolo, Yuba, Sutter)
  • North San Joaquin (Merced, San Joaquin, Stanislaus)
  • South San Joaquin (Kern, Madera, Tulare, Fresno, Kings)
Click an image for larger view

The Central Valley of California
Part of the Valley as seen from overhead
Part of the Valley as seen from overhead
Central California in the summer
Central California in the summer
There are around 6.6 million people living in the Central Valley, and it is the single fastest growing region in the state of California. There are 10 Metropolitan Statistical Areas (MSA) in the Central Valley. They are set out below by (MSA) population. The largest city is Fresno, followed by the state capital Sacramento.


The flat floor of the valley lies in stark contrast with the gentle hills and rugged mountain terrain that is typical of the majority of California. Some think the valley had it's beginnings below sea level when an offshore trench pushed down by the process in which rocks break and move or are displaced along the fractures. of the Farallon Plate and by the notable San Joaquin Seismic Fault a known Central Valley feature. It was later surrounded by the uplifting of the Coast Ranges, where the original outlet flowed into The Monterey Bay.

The Faulting shifted the Coast Ranges Southward, and a new outlet occurred close to what is now The San Francisco Bay. Over thousands of years, the central valley was saturated by sediments from these mountain ranges, in addition to the continued elevating of the Sierra Nevada on the east; this filling in due course created an astonishing flatness rising barely above sea level. Prior to the massive aqueduct and flood control system was constructed in California, Each year, the annual snow melt transformed a good part of the the valley into an huge inland lake.

The Sutter Buttes are the single notable exception to the flat floor of the valley, the leftovers of a long extinct volcano located just northwest from Yuba City being 44 miles north from the City of Sacramento.

The Central Valley also hides a substantial geologic feature located underneath the delta. The Stockton Arch is an upward warping of the crust situated beneath the sediments of the valley floor. The Stockton Arch extends from Northeast to Southwest across the valley.

An example of the extreme differences between the geology of the valley floor and that of Mount Diablo and the rugged hills of the Coast Ranges (Between Tracy and Stockton, CA:Interstate 5)

Physiographically, the Central Valley is situated within the California Trough physiographic region, which is part of the larger Pacific Border province, which in turn is part of the Pacific Mountain System.

Valley Climate

In Stanislaus County there is December tule fog. While the northern part of the greater Central Valley features a warm Mediterranean type environment (Koppen climate classification Csa); while the more southern parts located in rainshadow zones are sufficiently dry to be Mediterranean steppe (BShs, as in and around the Fresno area) or even some low-latitude desert (BWh, such as in and around the Bakersfield area). It is dry and hot during the summer while damp and cool in the winter, when reoccurring ground fog regionally known as "tule fog" can shroud vision. Daytime temperatures in the summer range 90 F (32 C), with occasional heat waves bringing temperatures over and above 104 F (40 C). From mid Autumn to spring is considered the rainy season - while aloft southeasterly winds of late summer, can bring tropical origin, thunderstorms mostly appearing in the southern portion of the San Joaquin Valley although sometimes occuring in the Sacramento Valley area. The northern part of the Central Valley obtains a greater amount of rain than the semidesert climate of the southern half 

Rivers and The Delta

Sacramento / San Joaquin Delta Homes the Sacramento River
Homes on the Sacramento River
View of the Deep Water Channel at the Port of Stockton - thumb
View of the Deep Water Channel / San Joaquin River at the Port of Stockton
The Sacramento and San Joaquin Rivers pass by way of the northern and southern portions of the central valley region, respectively. Then the two rivers merge to create the Sacramento-San Joaquin River Delta, a unique wrong side up river delta, situated the back side of the Carquinez Strait. Watercourses in the southernmost third of the San Joaquin Valley conclude in Buena Vista Lake and Tulare Lake. However, by the middle of the twentieth century, just about every drop the water flowing in these watersheds was redirected for agriculture use and those lakes are normally dry except during unusually large floods from snowmelt. Major tributaries include :

Sacramento Valley

  • Sacramento River
  • Pit River
  • Feather River
  • Yuba River
  • Dry Creek
  • American River

San Joaquin Valley

These rivers are not tributary to the San Joaquin River:
  • Kings River
  • Kaweah River
  • Tule River
  • Kern River


Most low lying lands in the Central Valley are have a tendancy to flood. Major public works projects originating in the 1930s set about to reduce the degree of flooding from snowmelt by the construction of huge dams. Iit was determined In 2003 that Sacramento had the distinction possessing both the least amount of protection against and just about the greatest flood risk. Congress granted $220 million to deter the flood threat in Sacramento County alone. Other valley counties that often face the threat of flooding are Stanislaus, Yuba, and San Joaquin.


West of Brookside thumbnail - May 2009

A typical Central Valley scene at ground level

The primary commerce in most of the Central Valley is agriculture based. A large and consistent workforce of government employees in Sacramento area is a notable exclusion to the prevalence of agriculture, where government employees assisted in guiding the economy in the opposite direction to agriculture. Conversely to the state hiring curbs and the shutting down of several of military operations, the Sacramento economy has continued to prosper and the diversify more closely resembles that of the close by San Francisco Bay Area. The main supply for the growing population are people seeking lower costs of housing therefore migrating from the Bay Area, additionally immigration from Central America, Asia, Mexico, Ukraine and other parts of the former Soviet Union. .


One of the greatest productive agricultural regions in the world, The Central Valley, occupying less than 1 percent of the entire USA farmland, grows 8 percent of the nations agricultural crops by value: 2002., 17 billion USD. The agricultural productivity depends upon irrigation from both diversion of surface water and pumping of groundwater pumping using wells. Almost one-sixth of the U.S. irrigated land is located in the Central Valley.

The Central Valley grows virtually every kind of non-tropical crop and is the chief source for many food products consumed throughout the United States, including almonds, tomatoes, cotton,, grapes, asparagus and apricots

Out of the top five counties for U,S. agricultural sales, four are located in the Central Valley (Data from 2002). They are: Fresno County, number 1 with sales of $2.759 billion, Tulare County is number 2 with sales of $2.338 billion, and Kern County, number 4 with sales of $2.058, Merced County, number 5 with sales of $2.058 billion. Data from 2002.

 Early farming was focused closer to the San Joaquin-Sacramento Delta, where there was a high year round water table and water transportation easier to come by, but later irrigation developments have been able to bring many more areas of the central valley into productive agricultural use. The Central Valley Project for example, formed in 1935 with dams and canals to store and redistribute water for municipal and agricultural uses.

National Farmworkers Association (NFWA)

It was around and in the community of Delano, located in the Central Valley where farm labor leader Cesar Chavez unionized Mexican American grape pickers into the National Farmworkers Association (NFWA), in the 1960s designed to make their working conditions better .

Social issues

San Joaquin Valley Congestion

Bakersfield, Modesto, Fresno, Tracy and Visalia, and have hit the ceiling in both population and in area since the 1980s as housing prices along the coast sky-rocketed. Many people from the San Francisco Bay Area and Los Angeles relocated to the growing suburbs of the San Joaquin Valley to find more affordable dwellings while keeping their jobs outside the Valley. This has led to horiffic traffic congestion commuting between their valley homes and their jobs in the Bay Area and the consequences have been increased air pollution. In fact, Air pollution a main environmental and health fear as far back as the 1960s was a factor in the 1967 creation of the California Air Resources Board. The absolute worst air quality and the highest asthma rates in California is now in the San Joaquin Valley.

Highways and infrastructure

The Central Valley in late August.
The Central Valley in late August.
See Transportation. Highways: State Route 99 and Interstate 5 and run, virtually parallel, north and south through the central valley, converging at both the north and south terminations of the valley. Interstate 80 crosses from a northeast-southwest direction from Rocklin through Vacaville. In augmentation to highways through the central valley area, the California Aqueduct parallels I-5 starting from Tracy, southwards to the Southern part of California and on across the Transverse Ranges and through the federal Central Valley Project and includes a large number of facilities between the Shasta Dam to the north and the Grapevine in the south. (Path 15 and Path 66) PG&E's and the Western Area Power Administration's three 500 kV wires system also pass through the central valley. In addition Path 26 passes through the most southern part of the San Joaquin Valley. Union Pacific Railroad and BNSF (Burlington Northern Santa Fe Railway) both maintain railways through the Central Valley. BNSF Bakersfield Subdivision proceeds from Bakersfield to four miles south of Fresno in Calwa, Starting at Calwa the BNSF Stockton Subdivision carries on to Port Chicago, just west of Antioch. From Port Chicago on through Martinez, Richmond and Emeryville on the way to Oakland The Union Pacific Railroad Martinez Subdivision carries on. The UP's Fresno Subdivision proceeds from Stockton on to Sacramento. Six daily Amtrak San Joaquin trains operate over these lines s.

See also

External links

Suggested Reading