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Boundaries and population Bounded by the Cascade Range to the north, the Sierra Nevada to the east, the Tehachapi Mountains to the south, and the Coast Ranges and San Francisco Bay to the west, the valley is a vast agricultural region drained by the Sacramento and San Joaquin rivers. These counties are commonly associated with the Central Valley: About 5.7 million people live in the Central Valley today. Geology The flatness of the valley floor contrasts with the rugged hills or gentle mountains that are typical of most of California's terrain. The valley is thought to have originated below sea level as an offshore area depressed by subduction of the Farallon Plate into a trench further offshore. It was later enclosed by the uplift of the Coast Ranges, with its original outlet into Monterey Bay. Faulting moved the Coast Ranges, and a new outlet developed near what is now San Francisco Bay. Over the millennia, the valley was filled by the sediments of these same ranges, as well as the rising Sierra Nevada to the east; that filling eventually created an extraordinary flatness just barely above sea level; at one time the annual snow melt turned the entire valley into an inland lake. The one notable exception to the flat valley floor is Sutter Buttes, the remnants of an extinct volcano just to the northwest of Yuba City which is 44 miles north of Sacramento. Climate The Central Valley is hot and dry during the summer and cool and damp in winter, when frequent ground fog known regionally as "tule fog" can be impenetrable. Summer temperatures reach into the mid 90s F (mid-high 30s C), and occasional heat waves might bring temperatures well over 100 F (38 C), with some locations topping out at around 120 F (49 C). Winter and spring comprise the rainy season — although during the late summer, southeasterly winds aloft can bring thunderstorms of tropical origin, mainly in the southern half of the San Joaquin Valley. The northern half of the Central Valley (the Sacramento Valley) has more precipitation than the dryer southern San Joaquin Valley. Rivers The Sacramento and San Joaquin Rivers flow through the northern and southern halves of the valley, respectively. Major tributaries of these two rivers include: Sacramento Valley San Joaquin Valley Major cities Major cities in the Central Valley include Fresno (464,727), Sacramento (450,000), Bakersfield (312,000) Stockton, ( 289,800) Modesto (206,300), and Visalia (110,000). Culture and politics Culturally and politically, the Central Valley is more conservative than the densely populated urban regions of California such as the San Francisco Bay Area and Los Angeles. Some cities, such as the college towns of Chico and Davis (home to the California State University, Chico and the University of California, Davis, respectively), are more liberal than the rest of the Valley, but their surrounding counties are typically conservative. The city of Sacramento is also more liberal than the Valley average, but its surrounding suburbs, particularly in Placer and El Dorado Counties, are conservative. The Central Valley should not be confused with "the Valley" that is home to Valley girls, the San Fernando Valley in the Los Angeles region. Agriculture The Central Valley is one of the most productive agricultural regions in the world. Virtually all non-tropical crops are grown here. Early farming was concentrated close to the Sacramento-San Joaquin Delta, where the water table was high year round and water transport more readily available, but subsequent irrigation projects have brought many more parts of the valley into productive use. For example, the Central Valley Project was formed in 1935 to redistribute and store water for agricultural and municipal purposes with dams and canals. It was in the Central Valley, especially in and around Delano, that farm labor leader Cesar Chavez organized Mexican American grape pickers into a union in the 1960s, the National Farmworkers Association (NFWA), in order to improve their working conditions. Social issues Since the 1980s, Bakersfield, Fresno, Visalia, Tracy and Modesto have exploded in both size and population, as housing values along the coast increased. Many people from the San Francisco Bay Area have moved out to more rural areas in search of more affordable housing, congesting roads between their Valley homes and their Bay Area jobs. These cities (along with Sacramento) have been confronted by big-city problems, including violent crime, drug trafficking, organized crime, traffic congestion, and air pollution. The San Joaquin Valley now has the worst air quality in California, along with the highest asthma rates, and like the more populous areas, its cities are subject to stringent anti-pollution laws. Highways and Infrastructure Interstate 5 and California State Route 99 run, roughly parallel, north-south through the valley. Interstate 80 crosses it east-west from Nevada to San Francisco. In addition to highways, the California Aqueduct follows I-5 from Tracy on southwards to Southern California across the Transverse Ranges. PG&E's and Western Area Power Administration's system of three 500 kV wires (Path 15 and Path 66) run through the valley. Path 26 also runs in the southernmost part of the San Joaquin Valley. | ||||||||||
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