The Central Valley is a broad, elongated, flat valley that dominates the interior of California. It is 40–60 mi (60–100 km) wide and runs approximately 450 mi (720 km) from north-northwest to south-southeast, inland from and parallel to the Pacific coast of the state. It covers approximately 18,000 sq mi (47,000 km2), about 11% of California's land area. The valley is bounded by the Coast Ranges to the west and the Sierra Nevada to the east.
The San Joaquin River is the longest river of Central California. The 366-mile (589 km) long river starts in the high Sierra Nevada, and flows through the rich agricultural region of the northern San Joaquin Valley before reaching Suisun Bay, San Francisco Bay, and the Pacific Ocean. An important source of irrigation water as well as a wildlife corridor, the San Joaquin is among the most heavily dammed and diverted of California's rivers.
The brush rabbit, or western brush rabbit, or Californian brush rabbit, is a species of cottontail rabbit found in western coastal regions of North America, from the Columbia River in Oregon to the southern tip of the Baja California Peninsula. Its range extends as far east as the eastern sides of the Sierra Nevada and Cascade mountain ranges.
The Sacramento–San Joaquin River Delta, or California Delta, is an expansive inland river delta and estuary in Northern California. The Delta is formed at the western edge of the Central Valley by the confluence of the Sacramento and San Joaquin rivers and lies just east of where the rivers enter Suisun Bay, which flows into San Francisco Bay, then the Pacific Ocean via San Pablo Bay. The Delta is recognized for protection by the California Bays and Estuaries Policy. Sacramento–San Joaquin Delta was designated a National Heritage Area on March 12, 2019. The city of Stockton is located on the San Joaquin River at the eastern edge of the delta. The total area of the Delta, including both land and water, is about 1,100 square miles (2,800 km2). Its population is around 500,000.
The Sacramento perch is an endangered sunfish native to the Sacramento–San Joaquin River Delta, Pajaro, and Salinas River areas in California, but widely introduced throughout the western United States.
Bell's vireo is a songbird that migrates between a breeding range in Western North America and a winter range in Central America. It is dull olive-gray above and whitish below. It has a faint white eye ring and faint wing bars.
The thicktail chub was a type of minnow that inhabited the lowlands and weedy backwaters of the Sacramento and San Joaquin Rivers in the Central Valley of California. It was once abundant in lowland lakes, marshes, ponds, slow-moving stretches of river, and, during years of heavy run-off, the surface waters of San Francisco Bay. The thicktail chub was one of the most common fish in California. Within Native American middens it represented 40% of the fish.
The delta smelt is an endangered slender-bodied smelt, about 5 to 7 cm long, in the family Osmeridae. Endemic to the upper Sacramento-San Joaquin Estuary of California, it mainly inhabits the freshwater-saltwater mixing zone of the estuary, except during its spawning season, when it migrates upstream to fresh water following winter "first flush" flow events. It functions as an indicator species for the overall health of the Delta's ecosystem.
The Sacramento blackfish is a species of freshwater fish in central California. A cyprinid, the blackfish is the sole member of its genus.
The California roach is a cyprinid fish native to western North America and abundant in the intermittent streams throughout central California. Once considered the sole member of its genus, it has recently been split into a number of closely related species and subspecies.
The tule perch is a surfperch (Embiotocidae) native to the rivers and estuaries of central California. It is the sole member of its genus, and the only freshwater surfperch.
The western brook lamprey is a small (<18 cm), widely distributed, non-parasitic species of jawless fish endemic to the freshwater coastal waterways of the Western United States and Canada. Its range extends from the North American Pacific coast from Taku River, southern Alaska, Queen Charlotte Islands, to central California, including Vancouver Island, with major inland distributions in the Columbia and Sacramento-San Joaquin watersheds.
The green sturgeon is a species of sturgeon native to the northern Pacific Ocean, from China and Russia to Canada and the United States.
The San Joaquin pocket mouse or Salinas pocket mouse is a species of rodent in the family Heteromyidae. It is endemic to California in the United States where it lives in desert and semi-desert habitats.
The Peripheral Canal was a series of proposals starting in the 1940s to divert water from California's Sacramento River, around the periphery of the San Joaquin-Sacramento River Delta, to uses farther south. The canal would have attempted to resolve a problem with the quality of water pumped south. Pumps create such a powerful suction that the boundary between freshwater to saltwater has shifted inland, negatively affecting the environment. The pumps have increased by 5 to 7 million acre-feet the amount of water exported each year to the Central Valley and Southern California. However, the peripheral canal as proposed would have reduced the overall freshwater flow into the Delta and move the freshwater-saltwater interface further inland, causing damage to Delta agriculture and ecosystems.
The Stone Lakes National Wildlife Refuge, located south of Sacramento, California, lies within the Sacramento-San Joaquin delta, the destination of thousands of migrating waterfowl, shorebirds, and other water birds. The refuge was established in 1994.
The Sacramento pikeminnow, formerly known as the Sacramento squawfish, is a large cyprinid fish of California, United States. It is native to the Los Angeles River, Sacramento-San Joaquin, Pajaro-Salinas, Russian River, Clear Lake and upper Pit River river basins. It is predatory and reaches up to 1.4 m (4.6 ft) in total length.
Mylopharadon conocephalus, known as the hardhead, is a freshwater ray-finned fish from the family Cyprinidae, the carps and minnows, which is endemic to California. It is the sole member of the monotypic genus Mylopharadon.
The bigscale logperch is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to North America where it occurs in the Sabine River of Louisiana, the Red River of Oklahoma and Arkansas, and to the Rio Grande drainage of Texas, New Mexico, and Mexico. It is now widespread in the Arkansas River basin where it was likely introduced. It was introduced to the Sacramento-San Joaquin River drainage in central California, and in reservoirs fed by the California Aqueduct where it is also widespread.
