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184-465: 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 km), about 11% of California's land area. The valley

368-414: A broader floodplain may result. Deposition dominates over erosion. A typical river basin or drainage basin will incorporate each of these different types of valleys. Some sections of a stream or river valleys may have vertically incised their course to such an extent that the valley they occupy is best described as a gorge , ravine , or canyon . Rapid down-cutting may result from localized uplift of

552-574: A chance to return for spawning. According to UC Davis Center for Watershed Sciences these rice fields adjacent to the Sacramento River will serve as potential nurseries for salmon. UC Davis also concluded from past experimental releases of salmon, that the Yolo Bypass floodway could have up to 57,000 acres of a productive breeding habitat with almost no cost to farmers. The Nigiri project has demonstrated off-season agriculture fields such as

736-533: A cirque glacier. During glacial periods, for example, the Pleistocene ice ages, it is in these locations that glaciers initially form and then, as the ice age proceeds, extend downhill through valleys that have previously been shaped by water rather than ice. Abrasion by rock material embedded within the moving glacial ice causes the widening and deepening of the valley to produce the characteristic U or trough shape with relatively steep, even vertical sides and

920-655: A drought. In 2014–2015, farm-related losses in California totaled $ 5 billion and 20,000 farmers also lost their jobs. Agriculture is the primary industry in most of the Central Valley. A notable exception is the Sacramento area, which hosts a large and stable workforce of government employees. Despite state hiring cutbacks and the closure of several military bases, Sacramento's economy has continued to expand and diversify and now more closely resembles that of

1104-629: A great network of pumps and canals that would take water from the Sacramento River in the north, and transport it to drought-prone central and southern California, especially the San Joaquin Valley. The Sacramento River basin receives "two-thirds to three-quarters of northern California's precipitation though it has only one-third to one-quarter of the land. The San Joaquin River watershed occupies two-thirds to three-quarters of northern California's land, but only collects one-third to one-quarter of

1288-494: A greater difference in the land in a shorter amount of time. According to a survey paper written in 1988 about a storm that occurred in 1982 in the Central Valley region, rainstorms that can cause that type of landslide to happen about every 5 years. Landslides to higher degrees, such as the ones that happened due to the 1982 storm, only occur every 20 to 100+ years. This intense storm in the San Francisco Bay area caused

1472-413: A large portion of the habitat currently used by migrating birds. Native bird populations have been declining steadily since the 19th century. Species that were once common but now are endangered or gone include the southwestern willow flycatcher , western yellow-billed cuckoo , least Bell's vireo , and warbling vireo . Another reason for dropping numbers are the introduction of non-native species, such as

1656-578: A large proportion of their population within a few decades of the arrival of Sutter and the following settlers, the start of the gold rush , not to mention the numerous battles fought between the settlers and native bands as well as the forced relocation of some of the tribes to Indian reservations in several places scattered around the Sacramento Valley, mainly in the Coast Ranges. In the early 1850s, several treaties were signed between

1840-419: A lot of damage as a result of moving debris and landslides. They caused damage to the land and put people living in these areas that are susceptible to these disasters in great harm. The aftermath of this storm involved millions of dollars in retributions to restore the land and surrounding areas. It also led people to make greater efforts into planning around the danger of these landslides, as in how to manipulate

2024-496: A name still often seen in scientific references (notably Great Valley Sequence ), as well as "Golden Empire", a booster name that is still referred to by some organizations (notably Golden Empire Transit , Golden Empire Council ). Ideas about what constitutes the “Central Valley” can vary from person-to-person. While almost all authoritative sources and external observers consider the Sacramento Valley to be part of

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2208-594: A narrow valley with steep sides. Gill is used to describe a ravine containing a mountain stream in Cumbria and the Pennines . The term combe (also encountered as coombe ) is widespread in southern England and describes a short valley set into a hillside. Other terms for small valleys such as hope, dean, slade, slack and bottom are commonly encountered in place-names in various parts of England but are no longer in general use as synonyms for valley . The term vale

2392-536: A part in the formation of the 300-mile (480 km) Monterey Submarine Canyon when sea levels were lower during the Ice Ages. The Monterey Bay outlet of the Sacramento and San Joaquin rivers was blocked off by uplift about 2 million years ago, and runoff from the Sierra began to transform the Central Valley into a gigantic lake, called Lake Clyde . This lake stretched 500 miles (800 km) north to south and

2576-403: A plethora of massive changes to the environment beginning in the 20th century. An early project was undertaken to raise the entire city of Sacramento about 11 feet (3.4 m) above its original elevation. This was followed by much bigger engineering projects to control and store the floodwaters of the Sacramento River; the building of these public works would radically transform the river during

2760-498: A pumping station (which replaced the Red Bluff Diversion Dam ) removes water for irrigation. Beyond Red Bluff the river reaches the low floodplain of the Sacramento Valley, receiving Mill Creek from the east and Thomes Creek from the west near Los Molinos , then Deer Creek from the east near Vina . Southeast of Corning , the Sacramento forms the boundary of Tehama County to the west and Butte County to

2944-432: A relatively flat bottom. Interlocking spurs associated with the development of river valleys are preferentially eroded to produce truncated spurs , typical of glaciated mountain landscapes. The upper end of the trough below the ice-contributing cirques may be a trough-end . Valley steps (or 'rock steps') can result from differing erosion rates due to both the nature of the bedrock (hardness and jointing for example) and

3128-853: A series of pumps that divert water into the California Aqueduct , which runs south along the length of the San Joaquin Valley. In parallel, pumps divert water into the Delta–Mendota Canal . The flow of the Sacramento River is further supplemented by a tunnel from the Trinity River (a tributary of the Klamath River , northwest of the Sacramento Valley) near Redding . Cities of the San Francisco Bay Area , also needing water, built aqueducts from

3312-465: A slower rate than that of the main valley floor; thus the difference in the two valleys' depth increases over time. The tributary valley, composed of more resistant rock, then hangs over the main valley. Trough-shaped valleys also form in regions of heavy topographic denudation . By contrast with glacial U-shaped valleys, there is less downward and sideways erosion. The severe downslope denudation results in gently sloping valley sides; their transition to

3496-626: A total of over 3,000 cubic feet per second (85 m /s) of water to irrigate some 150,000 acres (610 km ). In 1960, construction began on the State Water Project, whose primary purpose was to deliver water to Los Angeles and the San Francisco Bay Area. Oroville Dam – the tallest dam in the U.S. – was built on the Sacramento's largest tributary, the Feather River. A series of channels were enlarged in

3680-480: A turning point in the history of the Sacramento Valley, and California as a whole. In 1841, Sutter and his men built a fortress at the confluence of the Sacramento and American Rivers and the Mexican government granted him almost 50,000 acres (200 km ) of land surrounding the two rivers. Naming it New Helvetia, he created an agricultural empire in the lower Sacramento Valley, attracting several hundred settlers to

3864-427: A valley between its sides is referred to as the valley floor. The valley floor is typically formed by river sediments and may have fluvial terraces . The development of a river valley is affected by the character of the bedrock over which the river or stream flows, the elevational difference between its top and bottom, and indeed the climate. Typically the flow will increase downstream and the gradient will decrease. In

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4048-510: A variety of transitional forms between V-, U- and plain valleys can form. The floor or bottom of these valleys can be broad or narrow, but all valleys have a shoulder. The broader a mountain valley, the lower its shoulders are located in most cases. An important exception is canyons where the shoulder almost is near the top of the valley's slope. In the Alps – e.g. the Tyrolean Inn valley –

4232-472: A vast tidal estuary and inverted river delta of over 1,000 square miles (2,600 km ) which receives the entire run-off of the Central Valley, a region covering a third of California. The Sacramento is by far the largest contributor of fresh water to the Delta; in an average year, it accounts for more than 80 percent of the fresh water inflow. At Walnut Grove , the manmade Delta Cross Channel connects

4416-670: A watercourse only rarely. In areas of limestone bedrock , dry valleys may also result from drainage now taking place underground rather than at the surface. Rift valleys arise principally from earth movements , rather than erosion. Many different types of valleys are described by geographers, using terms that may be global in use or else applied only locally. Valleys may arise through several different processes. Most commonly, they arise from erosion over long periods by moving water and are known as river valleys. Typically small valleys containing streams feed into larger valleys which in turn feed into larger valleys again, eventually reaching

4600-469: Is Fresno followed by the state capital Sacramento . The following metropolitan and micropolitan statistical areas are listed from largest to smallest: After English and Spanish , Punjabi is the third most commonly spoken language in the Central Valley. The valley has the largest Sikh population in the nation . 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

4784-424: Is 43 miles (69 km) long and is maintained to a depth of 30 feet (9.1 m). The Sacramento River and its drainage basin once supported extensive riparian habitat and marshes , in both the Sacramento Valley and the Delta, home to a diverse array of flora and fauna. Due to the reclamation of land for agriculture and the regulation of seasonal flooding, the amount of water-based habitat declined greatly during

4968-405: Is a tributary valley that is higher than the main valley. They are most commonly associated with U-shaped valleys, where a tributary glacier flows into a glacier of larger volume. The main glacier erodes a deep U-shaped valley with nearly vertical sides, while the tributary glacier, with a smaller volume of ice, makes a shallower U-shaped valley. Since the surfaces of the glaciers were originally at

5152-644: Is bounded by the Coast Ranges to the west and the Sierra Nevada to the east. The Central Valley is a region known for its agricultural productivity . It provides a large share of the food produced in California. California provides more than half of the fruits, vegetables, and nuts grown in the United States. More than 7,000,000 acres (28,000 km) of the valley are irrigated via reservoirs and canals. The valley hosts many cities, including

5336-440: Is ideal for agriculture. The Central Valley is one of the United States' most productive growing regions. This is made possible by engineering the watercourses to prevent flooding during the spring snowmelt and drying up in the summer and autumn. Many dams, including Shasta Dam , Oroville Dam , Folsom Dam , New Melones Dam , Don Pedro Dam , Hetch Hetchy Dam , Friant Dam , Pine Flat Dam and Isabella Dam , were constructed on

5520-501: Is life-threatening or even fatal. Due to the agricultural industry's significant presence in the Valley, pesticide drift and leaching have become concerns. Residents risk contamination when living in proximity to application sites. Air pollution is a growing problem that affects all of the citizens in the Central Valley. Some reasons of poor air pollution in the Central Valley are due to agriculture and its geographical features. Since

5704-403: Is now San Francisco Bay . Over the millennia, the valley filled with 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. Before California's flood control and aqueduct system was built, annual snow melt turned much of the valley into an inland sea. The one notable exception to

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5888-501: Is only 50 meters (160 ft) deep while the main fjord is around 1,300 meters (4,300 ft) at the same point. Glaciated terrain is not the only site of hanging streams and valleys. Hanging valleys are also simply the product of varying rates of erosion of the main valley and the tributary valleys. The varying rates of erosion are associated with the composition of the adjacent rocks in the different valley locations. The tributary valleys are eroded and deepened by glaciers or erosion at

6072-489: Is part of the larger Pacific Border province, which in turn is part of the Pacific Mountain System . The Central Valley was formerly a diverse expanse of grassland, containing areas of prairie , desert grassland (at the southern end), oak savanna , riparian forest , marsh , several types of seasonal vernal pools , and large lakes such as now-dry Tulare Lake (once the largest freshwater lake west of

6256-399: Is released every Thursday, showing which parts of the U.S. are in a drought. It started in 2000, and since then the longest duration of a drought in California lasted a total of 376 weeks. It started on December 11, 2011, and ended on March 5, 2019. The most intense period captured on the drought monitor was on the week of July 29, 2014. It showed that 58.41% of California's land was affected by

6440-488: Is the word cwm borrowed from Welsh . The word dale occurs widely in place names in the north of England and, to a lesser extent, in southern Scotland. As a generic name for a type of valley, the term typically refers to a wide valley, though there are many much smaller stream valleys within the Yorkshire Dales which are named "(specific name) Dale". Clough is a word in common use in northern England for

6624-486: Is thought to have originated below sea level as an offshore area depressed by subduction of the Farallon Plate into a trench farther offshore. The valley has no earthquake faults of its own but is surrounded by faults to the east and west. The valley was 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

6808-629: Is used in England and Wales to describe a wide river valley, usually with a particularly wide flood plain or flat valley bottom. In Southern England, vales commonly occur between the outcrops of different relatively erosion-resistant rock formations, where less resistant rock, often claystone has been eroded. An example is the Vale of White Horse in Oxfordshire. Some of the first human complex societies originated in river valleys, such as that of

6992-445: Is very hot and dry during the summer and cool and damp in winter when frequent ground fog known regionally as " tule fog " can obscure vision. Summer daytime temperatures frequently surpass 100 °F (38 °C), and common heat waves might bring temperatures exceeding 115 °F (46 °C). Mid-autumn to mid-spring is the rainy season —although during the late summer, southeasterly winds can bring tropical thunderstorms, mainly in

7176-490: The Blessed Sacrament ". In the following years, two more Spanish expeditions traversed the lower part of the river, the last one in 1817. The next visitors were Hudson's Bay Company (HBC) fur trappers exploring southwards from the disputed Oregon Country , starting in the 1820s. The first organized expedition, led by Peter Skene Ogden , arrived in the area of Mount Shasta in 1826. By this time, California

7360-624: The California Coast Ranges , enclosing the Sacramento Valley and forcing the streams within to flow south instead of west, forming the ancestral Sacramento River. (The Klamath Mountains , which enclose the northwest part of the Sacramento Basin, were formed in the same way but are much older, dating back 7.5 million years.) It is possible that the river once had its outlet in Monterey Bay , and may have played

7544-677: The Carquinez Strait into San Pablo Bay and San Francisco Bay , joining the Pacific at the Golden Gate . Following the Columbia River , the Sacramento is the largest river by discharge on the Pacific coast of the continental United States. The natural runoff of the river is 22 million acre-feet (27 km ) per year, or about 30,000 cubic feet per second (850 m /s). Before dams were built on its tributaries,

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7728-479: The Golden Gate . Many of the islands lie below sea level because of intensive agriculture, and face a high risk of flooding, which would allow salt water to rush back into the delta, especially when too little fresh water is flowing in from the Valley. The Sacramento River carries far more water than the San Joaquin, with an estimated 22 million acre-feet (27 km) of virgin annual runoff, as compared to

7912-589: The Gulf of California just south of the US-Mexico border near the southeast part of the state, is far larger than the Sacramento in terms of length and drainage area but has a slightly smaller flow. The Sacramento, when combined with the Pit, is also one of the longest rivers in the United States entirely within one state—after Alaska 's Kuskokwim and Texas ' Trinity . The major drainage basins bordering that of

8096-716: The Klamath Diversion , proposed to send the entire flow of the Klamath River into the Sacramento River through a system of large reservoirs, canals, pumping stations and tunnels. Similarly, the Dos Rios Dam project would have diverted a considerable portion of the Eel River to the Sacramento. Both projects were defeated by local resistance, opposition from environmentalists, as well as the high capital cost. The Sacramento River Deep Water Ship Channel

8280-548: The Klamath Mountains , the river flows south for 400 miles (640 km) before reaching the Sacramento–San Joaquin River Delta and San Francisco Bay . The river drains about 26,500 square miles (69,000 km ) in 19 California counties , mostly within the fertile agricultural region bounded by the Coast Ranges and Sierra Nevada known as the Sacramento Valley , but also extending as far as

8464-513: The Latin terms for 'valley, 'gorge' and 'ditch' respectively. The German term ' rille ' or Latin term 'rima' (signifying 'cleft') is used for certain other elongate depressions on the Moon. See also: Sacramento River The Sacramento River ( Spanish : Río Sacramento ) is the principal river of Northern California in the United States and is the largest river in California. Rising in

8648-573: The Mokelumne River and Tuolumne River that run east to west across the middle part of the Central Valley. Most valley lowlands are prone to flooding, especially in the old Tulare Lake , Buena Vista Lake , and Kern Lake rivers. The Kings , Kaweah , Tule and Kern rivers originally flowed into these seasonal lakes, which would expand each spring to flood large parts of the southern San Joaquin Valley. Farms, towns, and infrastructure in these lakebeds are protected with levee systems, while

8832-504: The Nile , Tigris-Euphrates , Indus , Ganges , Yangtze , Yellow River , Mississippi , and arguably the Amazon . In prehistory , the rivers were used as a source of fresh water and food (fish and game), as well as a place to wash and a sewer. The proximity of water moderated temperature extremes and provided a source for irrigation , stimulating the development of agriculture . Most of

9016-574: The Oregon –California border, occasionally overflows into the Pit River during wet years, although this has not happened since 1881. The Goose Lake watershed is the only part of the Sacramento River basin extending into another state. Unlike most California rivers, the Pit and the McCloud Rivers are predominantly spring-fed, ensuring a large and consistent flow in even the driest of summers. At

9200-730: The Shasta , Modoc , and Achomawi /Pit River Tribes of the volcanic plateaus in the north; the Wintu and Hupa in the northern Klamath and Trinity mountains; the Nomlaki , Yuki , Patwin , and Pomo of the Coast Ranges; the Yana , Atsugewi , Maidu , Konkow , and Nisenan in the Sierra and their western foothills; and the Miwok in the south. Most of the Sacramento Valley's native peoples relied on hunting, gathering and fishing, although agriculture

9384-533: The Snake – Columbia River systems; geologic evidence indicates that the two were connected by a series of wetlands and channels about 4-5 million years ago. Located along the Pacific Flyway , the sprawling wetlands of the Sacramento Valley are an important stop for migratory birds; however, only a fraction of the historic wetlands remain. Seasonally flooded rice paddies in the Sacramento Valley comprise

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9568-548: The Tehachapi Mountains via four large pumping stations. The project irrigates 750,000 acres (300,000 ha) of land in the San Joaquin Valley and serves 22 million people in Central and Southern California. Over the years, several other plans materialized to divert rivers from California's North Coast into the Sacramento watershed, as future demand was projected to exceed supply. The only one to be built

9752-451: The Tehachapi Mountains . Riverside trees include willows, western sycamore ( Platanus racemosa ), box elder ( Acer negundo ), Fremont cottonwood ( Populus fremontii ), and the endemic valley oak ( Quercus lobata ). Another endemic species is brittlescale ( Atriplex depressa ) which grows in saline and alkali soils. The Central Valley was once home to large populations of pronghorn antelope ( Antilocapra americana ), elk including

9936-473: The Trinity River . It then swings east through Redding , the largest city of the Shasta Cascade region, and turns southeast, entering Tehama County . East of Cottonwood it receives Cottonwood Creek – the largest undammed tributary – from the west, then Battle Creek a short distance downstream. Below Battle Creek it carves its last gorge, Iron Canyon, emerging from the hills at Red Bluff , where

10120-668: The first civilizations developed from these river valley communities. Siting of settlements within valleys is influenced by many factors, including the need to avoid flooding and the location of river crossing points. Numerous elongate depressions have been identified on the surface of Mars , Venus , the Moon , and other planets and their satellites and are known as valles (singular: 'vallis'). Deeper valleys with steeper sides (akin to canyons) on certain of these bodies are known as chasmata (singular: 'chasma'). Long narrow depressions are referred to as fossae (singular: 'fossa'). These are

10304-437: The foothill yellow-legged frog and western spadefoot are listed as endangered species. Riparian and wetlands areas along the Sacramento once totaled more than 500,000 acres (2,000 km ); today only about 10,000 acres (40 km ) remains. Much of this consists of restored stretches and artificially constructed wetlands. Levee construction has prevented the river from changing course during winter and spring floods, which

10488-443: The 1950s the watershed has been intensely developed for water supply and the generation of hydroelectric power . Today, large dams impound the river and almost all of its major tributaries. The Sacramento River is used heavily for irrigation and serves much of Central and Southern California through the canals of giant state and federal water projects. While it is now providing water to over half of California's population and supporting

10672-417: The 20th century. From the late 19th century through the 20th century, California experienced an economic boom that led to the rapid expansion of both agriculture and urban areas. The Central Valley was becoming a heavily developed irrigation farming region, and cities along the state's Pacific coast and the Sacramento and San Joaquin rivers were growing rapidly, requiring river control to prevent flooding on

10856-419: The 20th century. Other human impacts include the heavy water consumption for agriculture and urban areas, and pollution caused by pesticides , nitrates , mine tailings , acid mine drainage and urban runoff . The Sacramento supports 40–60 species of fish, and 218 species of birds. The basin also has a number of endemic amphibian and fish species. Many Sacramento River fish species are similar to those in

11040-610: The Cascades; its headwaters rise on the western extreme of the Basin and Range Province , east of major Cascade volcanoes such as Mount Shasta and Lassen Peak . The other two are the Klamath River and Columbia River . By discharge, it is the second-largest contiguous U.S. river draining into the Pacific, after only the Columbia River, which has almost ten times the flow of the Sacramento. The Colorado River , which reaches

11224-743: The Central Valley (2007 Data). Early farming was concentrated close to the Sacramento-San Joaquin Delta, where the water table was high year-round and water transport was readily available. Subsequent irrigation projects brought many more parts of the valley into productive use. The even larger California State Water Project was formed in the 1950s and construction continued over the following decades. Valley At lower latitudes and altitudes, these glacially formed valleys may have been created or enlarged during ice ages but now are ice-free and occupied by streams or rivers. In desert areas, valleys may be entirely dry or carry

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11408-416: The Central Valley consists mostly of farming land, a wide, flat valley, the emissions from the soil that is used for growing produce are released into the air. The soil exudes nitrous oxide , an odorless and colorless gas that can be harmful when exposed to it for a long period of time, and incorporates itself into the ozone layer located at ground level. Production of nitrous oxide in California has shown that

11592-452: The Central Valley produces 8 percent of the nation's agricultural output by value: US$ 43.5 billion in 2013. California's farms and ranches earned almost $ 50 billion in 2018. The valley's productivity relies on irrigation from surface water and badly depleted underground aquifers . About one-sixth of the US' irrigated land is in the Central Valley. Virtually all non-tropical crops are grown in

11776-522: The Central Valley, which cause 312 landslides to move that year. Slow-moving landslides are impacted even if the intensity of the rainfall is not as severe. Consistent, moderately intense rainfall increases the saturation of water in the ground. This over-saturation is what causes the movement of a slow-moving landslide, rather than the more quick-moving and rigorous landslides that also occur in this region of California. Quick-moving landslides are caused by very intense rain, or sometimes earthquakes, that make

11960-401: The Central Valley, which is the primary source for produce throughout the United States, including tomatoes, grapes, cotton, apricots, and asparagus. Six thousand almond growers produced more than 600 million pounds (270 × 10 ^  kg) in 2000, about 70 percent of the world's supply and nearly 100 percent of domestic production. The US' top four counties in agricultural sales are in

12144-507: The Delta to facilitate water flow from the Sacramento to the Banks Pumping Plant and the California Aqueduct , which can carry as much as 4.2 million acre-feet (5.2 km ) of water each year. From its origin at the Delta the canal runs 444 miles (715 km) southwards through the west side of the San Joaquin Valley, providing irrigation water to farmlands along its length, and lifted almost 3,000 feet (910 m) over

12328-515: The Knaggs Ranch property within the Yolo Bypass by Sacramento River for four consecutive winters. UC Davis shares their results produced the fastest growth of juvenile Chinook salmon in the Central Valley to ever be recorded. The Nigiri project attempted to see if these floodplains as surrogate wetlands which can be controlled to copy the Sacramento River system's annual natural flooding cycle the native fish depend on. Runoff water from agriculture

12512-569: The Mississippi), Buena Vista Lake and Kern Lake . However, much of the Central Valley environment has been altered by human activity, including the introduction of exotic plants , notably grasses. The valley's grasslands, wetlands, and riparian forests constitute the California Central Valley grasslands , a temperate grasslands, savannas, and shrublands ecoregion . The foothill oak woodlands and chaparral that fringe

12696-638: The Pacific. The waters of the Tulare Basin essentially never reach the ocean (with the exception of Kings River waters diverted northward for irrigation), though they are connected by man-made canals to the San Joaquin. The valley encompasses all or parts of 18 California counties: Butte , Colusa , Glenn , Fresno , Kern , Kings , Madera , Merced , Placer , San Joaquin , Sacramento , Shasta , Stanislaus , Sutter , Tehama , Tulare , Yolo and Yuba . Older names include "the Great Valley",

12880-560: The Pit and McCloud Rivers provided the majority of river flow in dry summers when the Upper Sacramento and other tributaries slowed to a trickle. Monthly combined discharge of Sacramento River at Freeport and Yolo Bypass near Woodland (cfs) The Sacramento River's watershed is the largest entirely in California, covering much of the northern part of the state. The endorheic (closed) Goose Lake drainage basin in southern Oregon , however, has been known to overflow into

13064-521: The Sacramento River system during particularly wet years. The Sacramento River basin generally lies between the Sierra Nevada and Cascade Range on the east and the Coast Ranges and Klamath Mountains in the west, although the part of the basin drained by the Pit River extends east of the Cascades. The Pit River, has the distinction of being one of three rivers that cut through the main crest of

13248-484: The Sacramento River system is the Pit River, which is by far the largest of the three rivers flowing into Shasta Lake. At the USGS Montgomery Creek gauge, the average flow of the Pit River was 4,760 cu ft/s (135 m /s) for the period 1966–2013. By comparison, the Sacramento River at Delta gauge, a few miles above Shasta Lake, recorded an average of 1,191 cu ft/s (33.7 m /s) for

13432-578: The Sacramento River, 26 percent into the San Joaquin, and 27 percent into Tulare Lake. In the south part of the San Joaquin Valley, the alluvial fan of the Kings River and another from Coast Ranges streams have created a divide. The dry Tulare basin of the Central Valley receives flow from four major Sierra Nevada rivers, the Kings, Kaweah , Tule , and Kern . This basin, usually endorheic , formerly filled during snowmelt and spilled out into

13616-527: The Sacramento River, although not all of them are currently operational. The ones currently in operation are at Delta, California (near the source at Mount Shasta), at Keswick (near Redding), Colusa (about halfway down the river), Verona , and Freeport . The Freeport gauge, which sits just downstream of Sacramento, provides a relatively good metric of the annual outflow from the Sacramento River Basin. The average flow between 1949 and 2013

13800-545: The Sacramento Valley for about 447 miles (719 km). In the San Joaquin Valley, the San Joaquin River flows roughly northwest for 365 miles (587 km), picking up tributaries such as the Merced River , Tuolumne River , Stanislaus River and Mokelumne River . The Central Valley watershed encompasses over a third of California at 60,000 square miles (160,000 km), with 46 percent draining into

13984-512: The Sacramento Valley is below 300 feet (91 m) in elevation; in its lower course, the Sacramento River drops only about 1 foot (0.30 m) per mile. Between the bajadas or alluvial slopes extending from the foothills of the Sierra Nevada and Coast Ranges, are the low floodplains of the Sacramento River. The river flows at an elevation somewhat higher than the surrounding terrain due to deposits of sediment over millennia that created raised banks (essentially natural levees ). The banks separate

14168-574: The Sacramento Valley, with its high year-round flow and wide waterways, has been compared to the small and seasonal rivers of the San Joaquin basin; this also contributes to different identities between the two regions. Subregions and their counties commonly associated with the valley include: The four main population centers in the Central Valley area are roughly equidistant from the next. From south to north, they are Bakersfield , Fresno , Sacramento and Redding . These four cities act as hubs for regional commerce and transportation. The table displays

14352-525: The Sacramento and Feather Rivers into the Yolo Bypass , which parallels the Sacramento River down the west side of the valley. Cache Creek and Putah Creek , two major tributaries which formerly joined the Sacramento River from the west, are now intercepted by the Yolo Bypass via man-made channels. The main channel of the Sacramento flows south, forming the Yolo– Sacramento County line. As

14536-622: The Sacramento are that of the Klamath in the north, the San Joaquin and Mokelumne to the south and the Eel River in the west. The Russian River also lies to the west and the endorheic (closed) Honey Lake and Eagle Lake basins to the north. On the east side are many endorheic watersheds of the Great Basin including the Truckee River and Carson River . Parts of the Sacramento watershed come very close to, but do not extend past,

14720-582: The Sacramento to the Mokelumne River channel, allowing a portion of the water to be pumped south toward Clifton Court Forebay , the receiving reservoir for the main CVP and State Water Project aqueducts which irrigate millions of acres and supply water to over 23 million people in the San Joaquin Valley , the San Francisco Bay Area and Greater Los Angeles . Although river levels are tidally influenced here and occasionally as far north as Verona,

14904-487: The Sacramento with a portion of its historic flood plain, which it would have naturally flooded had the levee system not been in place. During the Great Depression in the 1930s, the first concrete proposals for a statewide water engineering project emerged, but when the state government could not sell the necessary bonds to fund the project, the federal government took over. The Central Valley Project , one of

15088-473: The Sacramento's main tributaries, enabling the regulation of water for irrigation and hydroelectric power. Starting in the late 1950s, two major canals were extended to irrigate the western side of the Sacramento Valley – the Tehama-Colusa and Corning Canals . Starting at the Red Bluff Diversion Dam on the Sacramento, the canals are 111 and 21 mi (179 and 34 km) long respectively, and divert

15272-411: The San Francisco Bay Area. Primary sources of population growth are Bay Area migrants seeking lower housing costs, augmented by immigration from Asia, Central America, Mexico, Ukraine, and the rest of the former Soviet Union. The Central Valley is one of the world's most productive agricultural regions. More than 230 crops are grown there. On less than 1 percent of the total farmland in the United States,

15456-634: The San Joaquin River. Called Tulare Lake , it is usually dry because the rivers feeding it have been diverted for agricultural purposes. Central Valley rivers converge in the Sacramento-San Joaquin Delta , a network of marshy channels, distributaries, and sloughs that wind around islands mainly used for agriculture. There the rivers merge with tidewater, and eventually reach the ocean after passing through Suisun Bay , San Pablo Bay , upper San Francisco Bay , and finally

15640-403: The San Joaquin's approximately 6 million acre-feet (7.4 km). Intensive agricultural and municipal water consumption decreased the rate of outflow to about 17 million acre-feet (21 km) for the Sacramento and 3 million acre-feet (3.7 km) for the San Joaquin. These figures vary widely from year to year. Over 25 million people, living in the valley and other regions of

15824-524: The Scandinavian ice sheet during the various ice ages advanced slightly uphill against the lie of the land. As a result, its meltwaters flowed parallel to the ice margin to reach the North Sea basin, forming huge, flat valleys known as Urstromtäler . Unlike the other forms of glacial valleys, these were formed by glacial meltwaters. Depending on the topography , the rock types , and the climate ,

16008-529: The Sierra Nevada. The watershed also has Lassen Volcanic National Park , which covers 106,000 acres (430 km ) centered on Lassen Peak, the southernmost Cascade volcano. Whiskeytown-Shasta-Trinity National Recreation Area , which is over 200,000 acres (810 km ) in size, straddles much of the upper Sacramento and Trinity Rivers, and is named for the three local reservoirs (Shasta Lake, Trinity Lake and Whiskeytown Lake ) which are popular tourist areas. Many other state parks and recreation areas lie within

16192-638: The U.S. government and the Native Americans involving their relocation onto a reservation in the Sierra foothills; this promise was broken. Therefore, in 1863, the tribes from the area surrounding the middle Sacramento and Feather rivers , the Konkow group, were removed and marched forcibly to the Round Valley Indian Reservation near the Eel River . A total of 461 people were forced from their homes, but only 277 made it to

16376-490: The United States, Sutter and other large landholders in California held on to their properties. In 1848 Sutter assigned James W. Marshall to build a sawmill on the South Fork American River at Coloma , where Marshall discovered gold. Although Sutter and Marshall originally intended to keep the find a secret, news soon broke attracting three hundred thousand hopefuls from all over North America, and even

16560-421: The Yolo Bypass in the rice field floodplains adjacent to the Sacramento River. The name comes from a form of Japanese sushi which contains a slice of fish on top of a compressed wedge of vinegared rice. Salmon migrate from the Central Valley rivers to the ocean where they increase in size for one to three years then return to rivers to spawn, if a young fish is larger when they enter the ocean, they will have more of

16744-511: The actual valley bottom is unclear. Trough-shaped valleys occur mainly in periglacial regions and in tropical regions of variable wetness. Both climates are dominated by heavy denudation. Box valleys have wide, relatively level floors and steep sides. They are common in periglacial areas and occur in mid-latitudes, but also occur in tropical and arid regions. Rift valleys, such as the Albertine Rift and Gregory Rift are formed by

16928-453: The addition of soil and fertilization can emit about 161,100 metric tons per year. Long term effects that nitrous oxide can have on a human being is loss of blood pressure, fainting, anemia, or lung cancer. The physical geographical attributes can also contribute to the air pollution quality. The Central Valley is surrounded by mountain ranges which can capture the pollution coming from the agricultural farming, preventing it from dispersing from

17112-602: The ancient path of the Siskiyou Trail, in the 1880s and 1890s. Many parts of the railroad were treacherous, especially in the mountainous areas north of Dunsmuir . It was not long after Sacramento surpassed a population of 10,000, then the Great Flood of 1862 swept away much of it (and almost everything else along the Sacramento River) and put the rest under water. The flood waters were exacerbated by

17296-557: The area, and relied on Native American labor to maintain his domain. Sutter had something of a two-faced relationship with the many Native American groups in the area. He was friendly with some of the tribes, and paid their leaders handsomely for supplying workers, but others he seized by force to labor in the fields. After the Bear Flag Revolt of 1846 and the Mexican–American War , in which California became part of

17480-548: The base of the Montezuma Hills , forming the border of Solano and Sacramento Counties. This part of the river is dredged for navigation by large oceangoing vessels and averages three-quarters of a mile (1.2 km) across. North of Antioch and Pittsburg , the Sacramento and San Joaquin Rivers join at the head of Suisun Bay , marking the official end of both rivers. The combined waters flow west through Suisun Bay and

17664-494: The border of California and Nevada . The basin's diverse geography ranges from the glacier-carved, snowcapped peaks of the Sierra Nevada to the sea-level (and often lower) marshes and farmlands of the Sacramento-San Joaquin Delta. The highest point is 14,104 feet (4,299 m) at Mount Shasta , a dormant stratovolcano near the headwaters of the Sacramento River. The Sierra Nevada peaks generally decrease in height from south to north—from over 10,000 feet (3,000 m) in

17848-430: The bypass recorded an average throughput of 4,809 cubic feet per second (136.2 m /s) between 1939 and 2013, mostly from December–March. The highest recorded flow was 374,000 cubic feet per second (10,600 m /s) on February 20, 1986. During the dry season of July through September, the bypass carries low to zero flow. Although the Sacramento River nominally begins near Mount Shasta, the true hydrological source of

18032-512: The center of an agricultural empire that provided food to feed the thousands of miners working in the hills as well as a place of financial exchange of all the gold that was mined. Sacramento was officially established in 1850 and was recognized as the state capital in 1854. As the economy of the Sacramento Valley grew, the Southern Pacific Railroad established tracks along the river to connect California with Oregon following

18216-578: The confluence of North, Middle and South Forks in the Trinity Mountains of Siskiyou County . It flows east into a small reservoir, Lake Siskiyou , before turning south. The river flows through a canyon for about 60 miles (97 km), past Dunsmuir and Castella , before emptying into Shasta Lake near Lakehead in Shasta County . The McCloud River rises on the east slope of Mount Shasta and flows south for 77 miles (124 km) through

18400-578: The counties of Central Valley and their respective population during the 2020 US Decennial Census. Total jobs for each county is from the U.S. Census Bureau, OnTheMap Application and LEHD Origin-Destination Employment Statistics (Beginning of Quarter Employment, 2nd Quarter of 2002–2020). As of 2020, some 7.2 million people lived in the Central Valley; it was the fastest-growing region in California. It includes 12 Metropolitan Statistical Areas (MSA) and 1 Micropolitan Statistical Area (μSA). Below, they are listed by MSA and μSA population. The largest city

18584-512: The counties. Many of the mountainous regions of the watershed are administered by the U.S. Forest Service . The Sacramento River watershed includes large areas of coniferous forests in the Mendocino and Trinity National Forests in the Coast Ranges, Shasta and Lassen National Forests in the southern Cascades and the Plumas , Tahoe and Eldorado National Forests on the western slopes of

18768-500: The delta of the Sacramento and San Joaquin Rivers. However, due to their vantage point, neither Fages nor any of his men saw the Sacramento clearly. They assumed that the San Joaquin, coming from the south, was the largest of the merging rivers they saw. In 1808, explorer Gabriel Moraga , on a journey to find suitable sites for the construction of missions, became the first foreigner to see the river clearly. Judging its huge breadth and power he named it Rio de los Sacramentos , or "River of

18952-501: The delta. Large blocks of desert scrubland exist in the southern San Joaquin Valley and the Carrizo Plain , just outside the valley, but offering a similar landscape. The wetlands have been the target of rescue operations to restore areas replaced by agriculture. These patches of natural habitat are disconnected, which is particularly damaging for wildlife that is used to migrating along the rivers. Agriculture, grazing land, and

19136-407: The draining of lakes and rivers have radically altered valley habitats. Most of the grassland has been overtaken by new species; most vernal pools have been destroyed, leaving only those on the higher slopes; the marshland has been drained, and the riverbank woodlands have nearly all been affected. The valley gives its name to Valley fever , which is primarily a disease of the lungs that is common in

19320-559: The drier San Joaquin Valley in the south, and the Tulare Basin and its semi-arid desert climate at the southernmost end. The Sacramento and San Joaquin river systems drain their respective valleys and meet to form the Sacramento–San Joaquin River Delta , a large expanse of interconnected canals , stream beds , sloughs , marshes and peat islands. The delta empties into the San Francisco Bay , and ultimately into

19504-609: The east. A few miles downstream it forms the border of Butte County and Glenn County to the west. Stony Creek joins from the west in Glenn County, near Hamilton City and about 15 miles (24 km) west of Chico . The river then forms the Glenn– Colusa County line for a short distance before crossing entirely into Colusa County. It passes by the Sutter Buttes , a group of volcanic hills that rise abruptly from

19688-467: The eastern boundary of the Yolo Bypass . The manually operated Sacramento Weir, located across from downtown Sacramento on the west side of the river, serves to relieve floodwater pressure from the American River by allowing it to drain west into the Yolo Bypass instead of continuing down the Sacramento River. Downstream of Sacramento, the river enters the Sacramento–San Joaquin River Delta ,

19872-518: The endemic tule elk subspecies ( Cervus elaphus nannodes ), mule deer ( Odocoileus hemionus ), California ground squirrels , gophers , mice, hare, rabbits and kangaroo rats , along with their predators including the San Joaquin kit fox (an endangered subspecies surviving on the San Joaquin Valley's hillsides). The valley's wetlands were an important habitat for wintering waterbirds and migrating birds of other kinds. Reptiles and amphibians of

20056-612: The expansion of the Earth 's crust due to tectonic activity beneath the Earth's surface. There are many terms used for different sorts of valleys. They include: Similar geographical features such as gullies , chines , and kloofs , are not usually referred to as valleys. The terms corrie , glen , and strath are all Anglicisations of Gaelic terms and are commonly encountered in place-names in Scotland and other areas where Gaelic

20240-522: The first significant rainfall. The official season is from November 1 to March 31. This phenomenon is named after the valley's tule grass wetlands ( tulares ). Auto collisions caused by the tule fog are the leading cause of weather-related casualties in California. Two river systems drain and define the two parts of the Central Valley. The Sacramento River , along with its tributaries the Feather River and American River , flows southwards through

20424-491: The flat valley floor is Sutter Buttes , the remnants of an extinct volcano just to the northwest of Yuba City . Another significant geologic feature of the Central Valley lies hidden beneath the delta. The Stockton Arch is an upwarping of the crust beneath the valley sediments that extends southwest to northeast across the valley. The Central Valley lies within the California Trough physiographic section, which

20608-443: The flow slower and both erosion and deposition may take place. More lateral erosion takes place in the middle section of a river's course, as strong currents on the outside of its curve erode the bank. Conversely, deposition may take place on the inside of curves where the current is much slacker, the process leading to the river assuming a meandering character. In the lower valley, gradients are lowest, meanders may be much broader and

20792-467: The geographically similar Colusa Basin is located to the west. The Sutter Bypass begins at Colusa and runs parallel to the east side of the Sacramento River until reaching the confluence with the Feather River . The Yolo Bypass, located on the west side of the river, starts at the confluence of the Feather and rejoins the Sacramento in the Delta. Although termed "bypasses", the system essentially reconnects

20976-425: The gold fields. As the miners expanded their diggings deeper into the Sierra Nevada and Klamath Mountains, Native Americans were pushed off their land and a long series of skirmishes and fights began that continued until intervention by the state and national governments. The influx of migrants brought foreign diseases like malaria and smallpox , which American Indians had no immunity to. These diseases killed off

21160-426: The gold fields. By the late part of the century mining had ceased to be a major part of the economy, and many immigrants turned to farming and ranching. Many populous communities were established along the Sacramento River, including the state capital of Sacramento . Intensive agriculture and mining contributed to pollution in the Sacramento River, and significant changes to the river's hydrology and environment. Since

21344-611: The headwaters of the American River near Lake Tahoe , to 5,000 to 7,000 feet (1,500 to 2,100 m) in Lassen County where they adjoin the Cascade Range. On the west side, the Coast Ranges are the opposite, increasing in height to almost 10,000 feet (3,000 m) in the north. The arid volcanic plateaus in the northeast, which are characterized by alternating hills and large sedimentary basins, typically lie at elevations of 3,000 to 5,000 feet (910 to 1,520 m). Most of

21528-1100: The land in the delta to gradually sink since the late 19th century. Many of the delta islands would be underwater if not for the maintenance of the levees and pumps that keep them dry. Some of the "islands" are now up to 25 feet (7.6 m) below the adjacent channels and sloughs. The Sacramento River watershed is home to about 2.8 million people; more than two-thirds live within the Sacramento metropolitan area . Other important cities are Chico , Redding , Davis and Woodland . The Sacramento River watershed covers all or most of Shasta , Tehama , Glenn , Butte , Plumas , Yuba , Sutter , Lake and Yolo Counties. It also extends into portions of Siskiyou , Modoc , Lassen , Lake (in Oregon), Sierra , Nevada , Placer , El Dorado , Sacramento , Solano and Contra Costa Counties. The river itself flows through Siskiyou, Shasta, Tehama, Butte, Glenn, Colusa, Sutter, Yolo, Sacramento, Solano and Contra Costa, often forming boundaries between

21712-427: The land surface or rejuvenation of the watercourse as a result for example of a reduction in the base level to which the river is eroded, e.g. lowered global sea level during an ice age . Such rejuvenation may also result in the production of river terraces . There are various forms of valleys associated with glaciation. True glacial valleys are those that have been cut by a glacier which may or may not still occupy

21896-770: The land to accommodate the consequences. Out of the past twenty-two years, California has experienced significant drought conditions for thirteen years. From 2000 to 2018 was the second driest period that California has ever experienced. The driest three-year period ever in California was from 2012 to 2014. Three-quarters of the state of California is experiencing extreme drought conditions. There are also multiple types of droughts such as agricultural droughts, meteorological droughts, snow droughts, and hydrological droughts. All of these droughts affect California in different ways. Droughts can damage forests and can cause wildfires. Droughts cause forests to become dry which causes trees to die. Dead trees result in wildfires. The U.S. drought monitor

22080-550: The land was probably submerged under the Pacific), they were worn by erosion , and the present-day range only formed about 4 million years ago. The northern part of the Sacramento watershed is more ancient, and was formed by intense volcanic activity over 25 million years ago, resulting in lava flows that covered and created the Modoc Plateau, through which the Pit River flows. Mount Shasta and Lassen Peak are among

22264-471: The land. Most of the villages were small. Although it was once commonly believed that the original natives lived as tribes , they actually lived as bands , family groups as small as twenty to thirty people. The Sacramento Valley was first settled by humans about 12,000 years ago, but permanent villages were not established until about 8,000 years ago. Historians have organized the numerous separate original native groups into several "tribes". These are known as

22448-481: The largest irrigation projects in the world, was constructed by the U.S. Bureau of Reclamation beginning in 1935. Ultimately, the system would distribute 7 million acre-feet (8.6 km ) to irrigate 3 million acres (1.2 million ha) of land in the Sacramento and San Joaquin Valleys. Construction of Shasta Dam, the principal water storage facility in the Sacramento River system, started in 1938 and

22632-567: The late 1700s. The Spanish explorer Gabriel Moraga named the river Rio de los Sacramentos in 1808, later shortened and anglicized into Sacramento . In the 19th century, gold was discovered on a tributary of the Sacramento River, starting the California Gold Rush and an enormous population influx to the state. Overland trails such as the California Trail and Siskiyou Trail guided hundreds of thousands of people to

22816-560: The lower end of Shasta Lake is Shasta Dam , which impounds the Sacramento River for flood control, irrigation and hydropower generation. Before the construction of Shasta Dam, the McCloud River emptied into the Pit River, which joined the Sacramento near the former mining town of Kennett , submerged when Shasta Lake was filled. The Pit River Bridge , which carries Interstate 5 and the Union Pacific Railroad over

23000-542: The main channel of the Sacramento. The Sacramento River and the Sutter Bypass flow parallel for over 40 miles (64 km), rejoining on the border of Sutter County and Yolo County near Knights Landing . The Feather River , the largest tributary of the Sacramento, joins from the east at Verona directly below the Sutter Bypass. A second flood control structure, the Fremont Weir, diverts flood waters from both

23184-627: The middle of the Sacramento Valley, where it receives Butte Creek from the east at Colusa . Below Colusa the river flows south-southeast, forming the border of Colusa County and Sutter County to the east. About 20 miles (32 km) further downstream, the Sacramento River reaches the Tisdale Weir. During floods, water overtops the weir and flows east into the Sutter Bypass , the first of two major bypass channels that temporarily store and move floodwaters downstream to reduce pressure on

23368-525: The most productive agricultural area in the nation, these changes have left the Sacramento greatly modified from its natural state and have caused the decline of its once-abundant fisheries. The Sacramento River originates in the mountains and plateaus of far northern California as three major waterways that flow into Shasta Lake : the Upper Sacramento River, McCloud River and Pit River . The Upper Sacramento begins near Mount Shasta , at

23552-413: The most recent being the Great Flood of 1862 . Dams, levees and floodways constructed during the 20th century have thus far prevented this phenomenon from re-occurring. The Sacramento River and its valley were one of the major Native American population centers of California. The river's abundant flow and the valley's fertile soil and mild climate provided enough resources for hundreds of groups to share

23736-599: The numerous Cascade Range volcanoes that still stand in the area. As the Sierra rose, water erosion and glaciation carved deep canyons, depositing massive amounts of sediment to form a coastal plain between the mountains and the Pacific Ocean. About 3 million years ago, multiple terranes were formed and smashed into the North American Plate from the Pacific Plate, causing the uplift of

23920-463: The ocean or perhaps an internal drainage basin . In polar areas and at high altitudes, valleys may be eroded by glaciers ; these typically have a U-shaped profile in cross-section, in contrast to river valleys, which tend to have a V-shaped profile. Other valleys may arise principally through tectonic processes such as rifting . All three processes can contribute to the development of a valley over geological time. The flat (or relatively flat) portion of

24104-520: The one hand, and to ensure a consistent supply of water on the other. The U.S. Army Corps of Engineers and the State of California completed reports as early as the 1870s and 1880s which outlined future development of the Sacramento, Feather, Yuba and Bear rivers. In 1873, Colonel B.S. Alexander of the Army Corps of Engineers surveyed the Central Valley's hydrology and irrigation systems and proposed

24288-496: The other areas in California. The Central Valley is also expanding in the number of people that coincide in that area, so it increases the number of cars which can also contribute to the amount of emission that is in the air. The northern Central Valley has a hot Mediterranean climate ( Köppen climate classification Csa ); the more southerly parts in rainshadow zones are dry enough to be Mediterranean steppe or even low-latitude desert ( BWh , as in areas around Bakersfield ). It

24472-626: The parasitic cowbird , which lays its eggs in the nests of other bird species causing its hatchlings to compete with the others for food. There were once 9 species of amphibians that used the Sacramento River, but some have become extinct and most other populations are declining due to habitat loss caused by agriculture and urban development. Amphibians originally thrived in the marshes, sloughs, side-channels and oxbow lakes because of their warmer water, abundance of vegetation and nutrients, lower predator populations and slower current. This population once included several species of frogs and salamanders;

24656-410: The period 1945–2013. The McCloud River had an average discharge of 775 cu ft/s (21.9 m /s) for the 1967–2013 period. Since the 1960s, the McCloud River flow has been reduced and the Pit River flow increased due to diversion of water for hydropower generation; however the total volume of water entering Shasta Lake remains the same. Before Shasta Dam was built, the volcanic springs feeding

24840-436: The power of the moving ice. In places, a rock basin may be excavated which may later be filled with water to form a ribbon lake or else by sediments. Such features are found in coastal areas as fjords . The shape of the valley which results from all of these influences may only become visible upon the recession of the glacier that forms it. A river or stream may remain in the valley; if it is smaller than one would expect given

25024-411: The precipitation." The topography of the Sacramento River watershed makes it particularly prone to flooding. Storm water runs quickly off the steep mountains flanking the Sacramento Valley, but with few exceptions the alluvial valley floor is strikingly flat, slowing down the runoff and causing it to overflow the river banks. Before flood control works were built, the winter floods frequently transformed

25208-484: The pressure of floodwaters on the main channel. The bypasses are then allowed to drain slowly once flood crests have passed. For most of the year, the bypasses remain dry and are used for annual crops such as rice. Some of the principal features are the Butte Basin, Colusa Basin, Sutter Bypass and the Yolo Bypass. The Butte Basin is a large lowland area on the east side of the river between Hamilton City and Colusa ;

25392-436: The reservation; the others perished of disease, starvation or exhaustion. As mining developed from simple methods such as panning and sluicing to a new form of commercialized extraction, hydraulic mining , profits from the petering gold rush made a second leap, earning more profits than placer miners in the early years had ever made. The city of Sacramento , founded on the original site of Sutter's fort, began to flourish as

25576-550: The reservoir, is structurally the highest double-decked bridge in the United States (although most of the bridge piers are submerged under Shasta Lake when the reservoir is full). The Upper Sacramento River canyon also provides the route for I-5 and the railroad between Lakehead and Mount Shasta. Below Shasta Dam the Sacramento River enters the foothills region of the northern Sacramento Valley. It flows through Keswick Dam , where it receives about 1,200,000 acre⋅ft (1.5 × 10  million km ) of water per year diverted from

25760-473: The rice fields under the Yolo Bypass next to Sacramento River can serve as an important floodplain habitat and feeding ground for juvenile or endangered fish. UC Davis noted juveniles grew much bigger and faster within the flooded rice fields when compared to those released in the Sacramento River. Public agencies, conservation groups and landowners have all been working together and conducting experiments since 2011. Experiments conducted on rice fields took place at

25944-497: The rich valley bottom and marsh lands. Before European contact, the indigenous population of the Sacramento Valley has been estimated at 76,000 people. The first outsiders to see the river were probably the members of a Spanish colonial-exploratory venture to Northern California in 1772, led by Captain Pedro Fages . The group ascended a mountain, likely in the hills north of Suisun Bay , and found themselves looking down at

26128-524: The risk of floods damaging properties increased greatly. The Great Flood of 1862 was the valley's worst flood in recorded history, flooding most of the valley and putting some places as much as 20 feet (6.1 m) under water. In 2003, it was determined that Sacramento had both the least protection against and nearly the highest risk of flooding. Congress then granted a $ 220 million loan for upgrades in Sacramento County. Other counties in

26312-403: The river after use) are about 4.72 million acre-feet (5.82 km ) for irrigation and 491,000 acre-feet (0.606 km ) for urban use. An additional 7.61 million acre-feet (9.39 km ) is reserved for environmental uses, primarily to maintain a minimum fresh water outflow in the Delta to combat salinity. The U.S. Geological Survey (USGS) has stream gauges on 25 locations along

26496-507: The river continues south it approaches the Sacramento metro area, the largest population center in the watershed. Sacramento International Airport is located on the east bank of the river near Fremont. Near downtown Sacramento it receives the American River from the east, then passes under the historic Tower Bridge and Interstate 80 Business . The California State Capitol sits less than zero point five miles (0.80 km) east of

26680-471: The river flooded up to 650,000 cubic feet per second (18,000 m /s) during the rainy season, equal to the flow of the Mississippi River . Late summers of particularly dry years could see flows drop below 1,000 cubic feet per second (28 m /s). Large volumes of water are withdrawn from the Sacramento River for irrigation, industry and urban supplies. Annual depletions (water not returned to

26864-415: The river from the lowlands to the east and west that once served as vast overflow basins during winter storms, creating large areas of seasonal wetlands . Since the 19th century, artificial levee systems have been constructed to enable farming in the fertile flood plain. Today there are 2,000,000 acres (8,100 km ) of irrigated farmland in the Sacramento Valley. Due to the reduction of the floodplain area,

27048-531: The river where the Tower Bridge crosses it. Shortly downstream, the Port of Sacramento is located on the west side of the Sacramento, connected to the river by a lock. The Sacramento River Deep Water Ship Channel provides access to the port from the Pacific, bypassing about 42 miles (68 km) of the winding lower Sacramento. The channel runs parallel to the Sacramento several miles to the west, and also forms

27232-650: The rivers, with many of them being part of the Central Valley Project . These dams impact physical, economic, cultural, and ecological resources: for example, enabling the development of its vast agricultural resources but leading to the loss of the Chinook salmon . Post-World War II demand for urban development, most notably the San Francisco Bay Area and the Los Angeles / Inland Empire / San Diego , required water resources. Moreover, agriculture in

27416-446: The same elevation , the shallower valley appears to be 'hanging' above the main valley. Often, waterfalls form at or near the outlet of the upper valley. Hanging valleys also occur in fjord systems underwater. The branches of Sognefjord are much shallower than the main fjord. The mouth of Fjærlandsfjord is about 400 meters (1,300 ft) deep while the main fjord nearby is 1,200 meters (3,900 ft) deep. The mouth of Ikjefjord

27600-493: The sediments washed down by the millions of tons by hydraulic mining, which filled the beds of the Sacramento, Feather and American rivers up to 7 feet (2.1 m) in Sacramento and also covered thousands of acres of Central Valley lands. A flood in 1875 covered the city of Marysville and when it subsided the town's streets were filled with debris and rocks washed down from the "hydraulicking" going on upstream. Repeated floods and increased demand for Sacramento River water saw

27784-550: The shoulders are quite low (100–200 meters above the bottom). Many villages are located here (esp. on the sunny side) because the climate is very mild: even in winter when the valley's floor is filled with fog, these villages are in sunshine . In some stress-tectonic regions of the Rocky Mountains or the Alps (e.g. Salzburg ), the side valleys are parallel to each other, and are hanging . Smaller streams flow into rivers as deep canyons or waterfalls . A hanging valley

27968-849: The size of its valley, it can be considered an example of a misfit stream . Other interesting glacially carved valleys include: A tunnel valley is a large, long, U-shaped valley originally cut under the glacial ice near the margin of continental ice sheets such as that now covering Antarctica and formerly covering portions of all continents during past glacial ages. Such valleys can be up to 100 km (62 mi) long, 4 km (2.5 mi) wide, and 400 m (1,300 ft) deep (its depth may vary along its length). Tunnel valleys were formed by subglacial water erosion . They once served as subglacial drainage pathways carrying large volumes of meltwater. Their cross-sections exhibit steep-sided flanks similar to fjord walls, and their flat bottoms are typical of subglacial glacial erosion. In northern Central Europe,

28152-550: The southern Cascade Range , roughly parallel to the Upper Sacramento, eventually to reach the McCloud Arm of Shasta Lake. The Pit River, by far the largest of the three, begins in Modoc County in the northeastern corner of California. Draining a vast and remote volcanic highlands area, it flows southwest for nearly 300 miles (480 km) before emptying into Shasta Lake near Montgomery Creek . Goose Lake , straddling

28336-556: The southern Central Valley required far more water than was available locally. The Feather River in the Sacramento Valley was looked to as a water source, leading to the California State Water Project . This transports water to the southern San Joaquin Valley and urban areas south of the Tehachapi Mountains. Runoff from the Sacramento and San Joaquin Rivers is intercepted in the delta through

28520-455: The southern half of the San Joaquin Valley but occasionally to the Sacramento Valley . The northern half of the Central Valley receives greater precipitation than the semidesert southern half. Frost occurs at times in the fall months, but snow is extremely rare. Tule fog / ˈ t uː l iː / is a thick ground fog that settles along the valley's length. Tule fog forms during the late fall and winter (California's rainy season ), after

28704-516: The southernmost large runs of chinook salmon in North America. For about 12,000 years, humans have depended on the vast natural resources of the watershed, which had one of the densest Native American populations in California. The river has provided a route for trade and travel since ancient times. Hundreds of tribes sharing regional customs and traditions have inhabited the Sacramento Valley, first coming into contact with European explorers in

28888-400: The southwestern United States and northwestern Mexico. It is caused by the fungus Coccidioides immitis , which grows in soils in areas of low rainfall, high summer temperatures, and moderate winter temperatures. These fungal spores become airborne when the soil is disturbed by winds, construction, or farming. This illness frequently takes weeks or months to resolve. Occasionally Valley Fever

29072-499: The speed of flood flow in the Sacramento River has increased, creating a significant hazard for the farms and towns along its course. By the early 20th century engineers had realized not all the floodplains could be safely reclaimed, leading to the intentional creation of flood bypasses where development is limited to annual crops and recreational uses. Further south, much of the delta region is actually below sea level: subsidence caused by wind erosion and intensive farming have caused

29256-407: The state capital Sacramento , as well as Redding , Chico , Stockton , Modesto , Merced , Fresno , Visalia , Porterville , and Bakersfield . The Central Valley watershed comprises 60,000 square miles (160,000 km), or over a third of California. It consists of three main drainage systems: the Sacramento Valley in the north, which receives over 20 inches (510 mm) of rain annually;

29440-472: The state, rely on the water carried by these rivers. Sierra Nevada runoff provides one of California's largest water resources. The Sacramento River is the second largest river to empty into the Pacific from the contiguous United States , behind only the Columbia River and greater than the Colorado River . Combined with the fertile and expansive area of the Central Valley's floor, the Central Valley

29624-407: The upper valley, the stream will most effectively erode its bed through corrasion to produce a steep-sided V-shaped valley. The presence of more resistant rock bands, of geological faults , fractures , and folds may determine the course of the stream and result in a twisting course with interlocking spurs . In the middle valley, as numerous streams have coalesced, the valley is typically wider,

29808-407: The valley at the present day. Such valleys may also be known as glacial troughs. They typically have a U-shaped cross-section and are characteristic landforms of mountain areas where glaciation has occurred or continues to take place. The uppermost part of a glacial valley frequently consists of one or more 'armchair-shaped' hollows, or ' cirques ', excavated by the rotational movement downslope of

29992-559: The valley have been categorized as the California interior chaparral and woodlands ecoregion. The dominant grass of the valley was Nassella pulchra mixed with other species, but today only 1% of the grassland in the valley is intact. Grassland flowers include California poppy ( Eschscholzia californica ), lupins , and purple owl's clover ( Castilleja exserta ), which can still be seen, especially in Antelope Valley in

30176-511: The valley include the endemic San Joaquin coachwhip snake ( Masticophis flagellum ruddocki ), blunt-nosed leopard lizard ( Gambelia sila ), Gilbert's skink ( Eumeces gilberti ) and the western aquatic garter snake ( Thamnophis couchii ). Endemic invertebrates are present. The Central Valley is home to endemic fish species, including the Sacramento pikeminnow , Sacramento perch , Sacramento blackfish , and Sacramento splittail . The Great Valley Grasslands State Park preserves an example of

30360-418: The valley into an inland sea. In 1880 State Engineer William H. Hall developed the first flood control plan for the Sacramento River. Hall recognized that with the combination of flat topography and extremely heavy winter runoff volumes, a system of levees alone could not hope to contain flooding, as had been proven time and again in the flood prone city of Sacramento. The Sacramento River Flood Control Project

30544-493: The valley that often face flooding are Yuba , Stanislaus , and San Joaquin . There is a very strong positive correlation between rainfall and slow-moving landslides in Northern California, especially in the Central Valley region. Changes in climate and precipitation levels have shown that consistent average rainfall has increased the number and intensity of landslides within the past 5–6 years. This information

30728-597: The valley's native grass habitat , while oak savanna habitats survive near Visalia . Areas of wetland and riverside woodland are found in the north, especially by the Sacramento River system, including the Nature Conservancy 's Cosumnes River Preserve just south of Sacramento, Gray Lodge Wildlife Area, Butte Sink Wildlife Management Area , and other patches in the delta area. Remaining vernal pools include Pixley National Wildlife Refuge between Tulare, California , and Bakersfield and Jepson Prairie Preserve in

30912-417: The volcanic plateaus of Northeastern California. Historically, its watershed has reached as far north as south-central Oregon where the now, primarily, endorheic (closed) Goose Lake rarely experiences southerly outflow into the Pit River , the most northerly tributary of the Sacramento. The Sacramento and its wide natural floodplain were once abundant in fish and other aquatic creatures, notably one of

31096-490: The water stays fresh in all but the driest years. Saltwater intrusion from the Pacific Ocean was one of the main reasons for the construction of the federal Central Valley Project (CVP), whose dams maintain a minimum flow in the Sacramento River to keep seawater at bay. Below Rio Vista , the lower Sacramento River is rejoined by the Deep Water Ship Channel and the Yolo Bypass and curves southwest along

31280-547: The watershed. By geologic standards, the Sacramento is a fairly young river; the borders of its watershed began to form only a few million years ago as magma welling up below the Earth's crust pushed up by the Pacific Plate colliding with the North American Plate caused the formation of the Sierra Nevada . Although mountains had existed as early as 100 million years ago in this region (before then

31464-528: The world, to the Sacramento River in search of fortunes, kicking off the California Gold Rush . People flocked to the region by the Oregon Trail -Siskiyou Trail, California Trail , Southern Emigrant Trail and various land and/or sea routes through the Isthmus of Panama and around southern South America by ship. Steamboats traveled up and down the Sacramento River carrying miners from San Francisco to

31648-431: The years to come, this path, which eventually extended from San Francisco to Portland, Oregon following parts of the Sacramento, Willamette , Klamath , Rogue , and other rivers would become an important trade and travel route. Although just one of thousands of American emigrants that poured into California over the next few years when California became part of the United States, John Augustus Sutter 's arrival marked

31832-468: The “Central Valley”, many residents consider the Central Valley to consist of only the San Joaquin Valley . This is perhaps due to significant landscape and cultural differences between the two; the San Joaquin Valley is poorer and drier with more fertile soil, while the Sacramento Valley is wealthier and wetter with poorer soils. The major presence of the Sacramento River and its tributaries in

32016-478: Was 23,330 cubic feet per second (661 m /s). The maximum recorded flow was 115,000 cubic feet per second (3,300 m /s) on February 19, 1986; the lowest was 3,970 cubic feet per second (112 m /s) on October 15, 1977. Flow in the Yolo Bypass , a relief channel designed to carry a portion of the flood waters in order to protect the Sacramento area, is not measured by the Freeport gauge. A separate gauge on

32200-528: Was at least 1,000 feet (300 m) deep. About 650,000 years ago the lake catastrophically overflowed, draining into San Francisco Bay and creating the Carquinez Strait , the only major break for hundreds of miles in the Coast Ranges. The narrow outlet trapped some of the sediments of the rivers in the Central Valley, forming the inland Sacramento-San Joaquin River Delta . Since then, this inland sea has periodically reformed during times of intense flooding,

32384-416: Was authorized by the federal government in 1917. While it intended to contain minor floods in the river banks by strengthening the existing levee system, the main feature was a series of bypasses, or sections of the valley intentionally designed to flood during high water. Weirs placed at strategic points along the Sacramento River release water into the bypasses when the river reaches a certain stage, relieving

32568-465: Was completed in 1945. Controlling runoff from the upper 6,600 square miles (17,000 km ) of the Sacramento River watershed, Shasta greatly reduces flood peaks on the middle and lower parts of the Sacramento River. Flood waters are stored for irrigation in dry years as well as navigation and electricity generation. In the following decades, more huge reservoirs – capable of storing a combined 13 × 10 acre-feet (16 km ) of water – were constructed on

32752-400: Was completed in 1963, and was built to facilitate navigation of large oceangoing ships from the Delta to the port of Sacramento. The channel bypasses the winding lower part of the Sacramento River between the state capital and the Delta thus reducing water travel times. It also serves to discharge floodwaters from the lower end of the Yolo Bypass . Built by the Army Corps of Engineers, the canal

32936-434: Was crucial to the renewal of existing wetlands and the creation of new ones. Since the late 19th century the river has been mostly locked in a fixed channel, which once could shift hundreds of feet or even several miles in a year because of floods. In 2010, about 100 miles (160 km) of the river's riparian forests were undergoing restoration. UC Davis initiated a project known as The Nigiri Project which takes place under

33120-414: Was once widespread. Strath signifies a wide valley between hills, the floor of which is either level or slopes gently. A glen is a river valley which is steeper and narrower than a strath. A corrie is a basin-shaped hollow in a mountain. Each of these terms also occurs in parts of the world formerly colonized by Britain . Corrie is used more widely by geographers as a synonym for (glacial) cirque , as

33304-643: Was practiced in a few areas. Settlement size ranged from small camps to villages of 30–50 permanent structures. Acorns were a staple food , and the Sacramento Valley's riparian zones, which supported seven species of native oaks, provided these in abundance. Native Americans pounded the acorns into flour, which they used to make bread and cakes. Abundant salmon and steelhead runs in the Sacramento River and its tributaries were harvested using fishing weirs, platforms, baskets and nets. The river also provided shellfish, sturgeon, eel and suckerfish They also hunted waterfowl, antelope and deer which all existed in huge numbers in

33488-456: Was shown in a study that focused on the behavior of these slow-moving landslides and how their nature changed with years of extreme average rainfall versus minimal average rainfall. In 2016, the average annual precipitation levels were lower because of a drought that was coming to an end at that time. The minimal rainfall in that year showed that 119 landslides had been moving. Comparatively, in 2017, there were very extreme levels of precipitation in

33672-404: Was the Trinity River Project (which would become part of the CVP), sending over 90 percent of the flow of that river into the Sacramento via a tunnel under the Klamath Mountains. Due to environmental damage and fish kills in the Trinity River, the volume of diverted water has been limited by law since the 1990s. Other, larger projects ultimately failed to take root. One of the most notorious,

33856-407: Was under the control of Mexico , although few Mexican settlers had come to what would later become the state, mostly settling in the small pueblos and ranchos along the south and central coast. The HBC mountain men created the Siskiyou Trail out of several Native American paths that ran through the mountains between Oregon's Willamette Valley and the northern part of the Sacramento Valley. In

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