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San Francisco Bay
San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland. San Francisco Bay drains water from approximately 40 percent of California. Water from the Sacramento and San Joaquin rivers, and from the Sierra Nevada mountains, flow into Suisun Bay, which then travels through the Carquinez Strait to meet with the Napa River at the entrance to San Pablo Bay, which connects at its south end to San Francisco Bay. It then connects to the Pacific Ocean via the Golden Gate strait. However, this entire group of interconnected bays is often called the ''San Francisco Bay''. The bay was designated a Ramsar Wetland of International Importance on February 2, 2017. Size The bay covers somewhere between , depending on which sub-bays (such as San Pablo Bay), estuaries, wetlands, and so on are included in the measurement. The main part of the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacramento River
The Sacramento River ( es, Río Sacramento) is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–San Joaquin River Delta and San Francisco Bay. The river drains about 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 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 the southernmost large runs of chinook salmon in North America. For about 12,000 years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Pablo Bay
San Pablo Bay is a tidal estuary that forms the northern extension of San Francisco Bay in the East Bay and North Bay regions of the San Francisco Bay Area in northern California. Most of the Bay is shallow; however, there is a deep water channel approximately in the middle of the bay, which allows access to major ports in Sacramento, Stockton, Benicia, and Martinez; and other smaller ports on the Sacramento–San Joaquin River Delta. Geography San Pablo Bay was named after Rancho San Pablo, a Spanish land grant given to colonial Alta California settlers in 1815, on the bay at the site of the present-day city of San Pablo. The bay is approximately across and has an area of approximately . The bay receives the waters of the Sacramento and San Joaquin rivers, via Suisun Bay and the Carquinez Strait on its northeast end, and it connects to the Pacific Ocean via the San Francisco Bay on its southern end. The bay is heavily silted from the contributions of the two rive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Runway
According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt, concrete, or a mixture of both) or a natural surface ( grass, dirt, gravel, ice, sand or salt). Runways, as well as taxiways and ramps, are sometimes referred to as "tarmac", though very few runways are built using tarmac. Takeoff and landing areas defined on the surface of water for seaplanes are generally referred to as waterways. Runway lengths are now commonly given in meters worldwide, except in North America where feet are commonly used. History In 1916, in a World War I war effort context, the first concrete-paved runway was built in Clermont-Ferrand in France, allowing local company Michelin to manufacture Bréguet Aviation military aircraft. In January 1919, aviation pioneer Orville Wright underlined the need for "distinctly m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Francisco International Airport
San Francisco International Airport is an international airport in an unincorporated area of San Mateo County, south of Downtown San Francisco. It has flights to points throughout North America and is a major gateway to Europe, the Middle East, Asia, and Australia. SFO is the largest airport in the San Francisco Bay Area and the second-busiest in California, after Los Angeles International Airport (LAX). In 2017, it was the seventh-busiest airport in the United States and the 24th-busiest in the world by passenger count. It is the fifth-largest hub for United Airlines, which operates out of Terminal 3 and the International Terminal. SFO functions as United's primary transpacific gateway. Additionally, SFO is a major maintenance hub for United Airlines and houses the SFO Museum that was created in 1980, the first museum in an international airport. It also serves as a hub for Alaska Airlines, which operates in Terminal 2. The airport is owned and operated by the C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marina District, San Francisco
The Marina District is a neighborhood located in San Francisco, California. The neighborhood sits on the site of the 1915 Panama–Pacific International Exposition, staged after the 1906 San Francisco earthquake to celebrate the reemergence of the city. Aside from the Palace of Fine Arts (POFA), all other buildings were demolished to make the current neighborhood. The Marina currently has the highest non-Hispanic white resident percentage of any recognized neighborhood in San Francisco. Location The area is bounded to the east by Van Ness Avenue and Fort Mason; on the west by Lyon Street and the Presidio National Park; on the south by Cow Hollow and Lombard St, which bisects the southern edge of the Marina District. The northern half of the Marina is a shoreline of the San Francisco Bay, and features the Marina Green, a park adjacent to the municipal boat marina from which the neighborhood takes its name. Much of the Marina is built on former landfill, and is susceptible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loma Prieta Earthquake
The 1989 Loma Prieta earthquake occurred on California's Central Coast on October 17 at local time. The shock was centered in The Forest of Nisene Marks State Park in Santa Cruz County, approximately northeast of Santa Cruz on a section of the San Andreas Fault System and was named for the nearby Loma Prieta Peak in the Santa Cruz Mountains. With an magnitude of 6.9 and a maximum Modified Mercalli intensity of IX (''Violent''), the shock was responsible for 63 deaths and 3,757 injuries. The Loma Prieta segment of the San Andreas Fault System had been relatively inactive since the 1906 San Francisco earthquake (to the degree that it was designated a seismic gap) until two moderate foreshocks occurred in June 1988 and again in August 1989. Damage was heavy in Santa Cruz County and less so to the south in Monterey County, but effects extended well to the north into the San Francisco Bay Area, both on the San Francisco Peninsula and across the bay in Oakland. No surface fau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Liquefaction
Soil liquefaction occurs when a cohesionless saturated or partially saturated soil substantially loses Shear strength (soil), strength and stiffness in response to an applied Shear stress, stress such as shaking during an earthquake or other sudden change in stress condition, in which material that is ordinarily a solid behaves like a liquid. In soil mechanics, the term "liquefied" was first used by Allen Hazen in reference to the 1918 failure of the Calaveras Dam in California. He described the mechanism of flow liquefaction of the embankment dam as: The phenomenon is most often observed in saturated, loose (low density or uncompacted), sandy soils. This is because a loose sand has a tendency to Compressibility, compress when a force, load is applied. Dense sands, by contrast, tend to expand in volume or 'Reynolds' dilatancy, dilate'. If the soil is saturated by water, a condition that often exists when the soil is below the water table or sea level, then water fills the ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dredging
Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing dams, dikes, and other controls for streams and shorelines; and recovering valuable mineral deposits or marine life having commercial value. In all but a few situations the excavation is undertaken by a specialist floating plant, known as a dredger. Dredging is carried out in many different locations and for many different purposes, but the main objectives are usually to recover material of value or use, or to create a greater depth of water. Dredges have been classified as suction or mechanical. Dredging has significant environmental impacts: it can disturb marine sediments, leading to both short- and long-term water pollution, destroy important seabed ecosystems, and can release human-sourced toxins captured in the sediment. Descripti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harbor
A harbor (American English), harbour (British English; see spelling differences), or haven is a sheltered body of water where ships, boats, and barges can be docked. The term ''harbor'' is often used interchangeably with ''port'', which is a man-made facility built for loading and unloading vessels and dropping off and picking up passengers. Ports usually include one or more harbors. Alexandria Port in Egypt is an example of a port with two harbors. Harbors may be natural or artificial. An artificial harbor can have deliberately constructed breakwaters, sea walls, or jettys or they can be constructed by dredging, which requires maintenance by further periodic dredging. An example of an artificial harbor is Long Beach Harbor, California, United States, which was an array of salt marshes and tidal flats too shallow for modern merchant ships before it was first dredged in the early 20th century. In contrast, a natural harbor is surrounded on several sides of land. Examples of n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Mining
Hydraulic mining is a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment.Paul W. Thrush, ''A Dictionary of Mining, Mineral, and Related Terms'', US Bureau of Mines, 1968, p.560. In the placer mining of gold or tin, the resulting water-sediment slurry is directed through sluice boxes to remove the gold. It is also used in mining kaolin and coal. Hydraulic mining developed from ancient Roman techniques that used water to excavate soft underground deposits. Its modern form, using pressurized water jets produced by a nozzle called a "monitor", came about in the 1850s during the California Gold Rush in the United States. Though successful in extracting gold-rich minerals, the widespread use of the process resulted in extensive environmental damage, such as increased flooding and erosion, and sediment blocking waterways and covering farm fields. These problems led to its legal regulation. Hydraulic mining has been used in various forms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
References
Reference is a relationship between objects in which one object designates, or acts as a means by which to connect to or link to, another object. The first object in this relation is said to ''refer to'' the second object. It is called a ''name'' for the second object. The second object, the one to which the first object refers, is called the ''referent'' of the first object. A name is usually a phrase or expression, or some other symbolic representation. Its referent may be anything – a material object, a person, an event, an activity, or an abstract concept. References can take on many forms, including: a thought, a sensory perception that is audible (onomatopoeia), visual (text), olfactory, or tactile, emotional state, relationship with other, spacetime coordinate, symbolic or alpha-numeric, a physical object or an energy projection. In some cases, methods are used that intentionally hide the reference from some observers, as in cryptography. References feature in many s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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