San Francisco Bay
San Francisco Bay | |
---|---|
Coordinates | 37°40′N 122°16′W / 37.67°N 122.27°W[1] |
Type | Bay |
River sources | Sacramento River San Joaquin River Petaluma River Napa River Guadalupe River |
Ocean/sea sources | Pacific Ocean |
Basin countries | United States |
Max. length | 97 km (60 mi) |
Max. width | 19 km (12 mi) |
Surface area | 400–1,600 sq mi (1,000–4,100 km2) |
Average depth | 12–15 ft (3.7–4.6 m)[2] |
Max. depth | 372 ft (113 m) |
Settlements | San Francisco San Jose Oakland |
Official name | San Francisco Bay/Estuary (SFBE) |
Designated | February 2, 2013 |
Reference no. | 2097[3] |
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 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, 2013, and the Port of Oakland on the bay is one of the busiest cargo ports on the west coast.
Size
The bay covers somewhere between 400 and 1,600 square miles (1,000–4,000 km2), depending on which sub-bays (such as San Pablo Bay), estuaries, wetlands, and so on are included in the measurement.[4][5][6] The main part of the bay measures three to twelve miles (5–19 km) wide east-to-west and somewhere between 48 miles (77 km)1 and 60 miles (97 km)2 north-to-south. It is the largest Pacific estuary in the Americas.
The bay was navigable as far south as San Jose until the 1850s, when hydraulic mining released massive amounts of sediment from the rivers that settled in those parts of the bay that had little or no current. Later, wetlands and inlets were deliberately filled in, reducing the bay's size since the mid-19th century by as much as one third. Recently, large areas of wetlands have been restored, further confusing the issue of the bay's size. Despite its value as a waterway and harbor, many thousands of acres of marshy wetlands at the edges of the bay were, for many years, considered wasted space. As a result, soil excavated for building projects or dredged from channels was often dumped onto the wetlands and other parts of the bay as landfill.
From the mid-19th century through the late 20th century, more than a third of the original bay was filled and often built on. The deep, damp soil in these areas is subject to
The
There are five large islands in San Francisco Bay.
Geology
San Francisco Bay is thought to represent a down-warping of the Earth's crust between the
Until the
History
The indigenous inhabitants of the San Francisco Bay are
The first recorded European discovery of San Francisco Bay was on November 4, 1769, when Spanish explorer Gaspar de Portolá, unable to find the Port of Monterey, continued north close to what is now Pacifica and reached the summit of the 1,200-foot-high (370 m) Sweeney Ridge, now marked as the place where he first sighted San Francisco Bay. Portolá and his party did not realize what they had discovered, thinking they had arrived at a large arm of what is now called Drakes Bay.[12] At the time, Drakes Bay went by the name Bahia de San Francisco and thus both bodies of water became associated with the name. Eventually, the larger, more important body of water fully appropriated the name San Francisco Bay.
The first European to enter the bay is believed to have been the Spanish explorer
The United States seized the region from Mexico during the Mexican–American War (1846–1848). On February 2, 1848, the Mexican province of Alta California was annexed to the United States with the signing of the Treaty of Guadalupe Hidalgo. A year and a half later, California requested to join the United States on December 3, 1849, and was accepted as the 31st State of the Union on September 9, 1850.
In 1921, a tablet was dedicated by a group of men including Lewis Francis Byington, in downtown San Francisco, marking the site of the original shoreline. The tablet reads: "This tablet marks the shore line of San Francisco Bay at the time of the discovery of gold in California, January 24, 1848. Map reproduced above delineates old shore line. Placed by the Historic Landmarks committee, Native Sons of the Golden West, 1921."[13]
The bay became the center of American settlement and commerce in the Far West through most of the remainder of the 19th century. During the
In 1910, the Southern Pacific railroad company built the Dumbarton Rail Bridge,[16] the first bridge crossing San Francisco Bay.[17] The first automobile crossing was the Dumbarton Bridge, completed in January 1927.[18] More crossings were later constructed – the Carquinez Bridge in May 1927,[19] the San Francisco–Oakland Bay Bridge in 1936,[20] the Golden Gate Bridge in 1937,[21] the Richmond–San Rafael Bridge in 1956,[22] and the San Mateo–Hayward Bridge in 1967.[23]
During the 20th century, the bay was subject to the 1940s Reber Plan, which would have filled in parts of the bay in order to increase industrial activity along the waterfront. In 1959, the United States Army Corps of Engineers released a report stating that if current infill trends continued, the bay would be as big as a shipping channel by 2020. This news created the Save the Bay movement in 1960,[24] which mobilized to stop the infill of wetlands and the bay in general, which had shrunk to two-thirds of its size in the century before 1961.[25]
The San Francisco Bay continues to support some of the densest industrial production and urban settlement in the United States. The San Francisco Bay Area is the American West's second-largest urban area, with approximately seven million residents.[26]
Ecology
Despite its urban and industrial character, San Francisco Bay and the
Most famously, the bay is a key link in the
Salt produced from San Francisco Bay is produced in
Low-salinity salt ponds mirror the ecosystem of the bay, with fish and fish-eating birds in abundance. Mid-salinity ponds support dense populations of brine shrimp, which provide a rich food source for millions of shorebirds. Only salt-tolerant micro-algae survive in the high salinity ponds, and impart a deep red color to these ponds from the pigment within the algae protoplasm. The salt marsh harvest mouse is an endangered species endemic to the wetlands of the San Francisco Bay with a high salt tolerance. It needs native pickleweed, which is often displaced by invasive cordgrass, for its habitat.[30]
The seasonal range of water temperature in the bay is from January's 53 °F (12 °C) to September's 60 °F (16 °C) when measured at
For the first time in 65 years,
The common bottlenose dolphin (Tursiops truncatus) has been extending its current range northwards from the Southern California Bight. The first coastal bottlenose dolphin in the Bay Area in recent times was spotted in 1983 off the San Mateo County coast in 1983. In 2001, bottlenose dolphins were first spotted east of the Golden Gate Bridge and confirmed by photographic evidence in 2007. Zooarcheological remains of bottlenose dolphins indicated that bottlenose dolphins inhabited San Francisco Bay in prehistoric times until at least 700 years before present, and dolphin skulls dredged from the bay suggest occasional visitors in historic times.[35]
Pollution
Industrial, mining, and other uses of
The bay also has some of the highest levels of dissolved inorganic nitrogen known from any coastal water body, mostly originating from treated wastewater from
The bay was once considered a hotspot for polybrominated diphenyl ether (
Bay fill and depth profile
San Francisco Bay's profile changed dramatically in the late 19th century and again with the initiation of dredging by the
In the 1860s and continuing into the early 20th century, miners dumped staggering quantities of mud and gravel from hydraulic mining operations into the upper Sacramento and San Joaquin Rivers. GK Gilbert's estimates of debris total more than eight times the amount of rock and dirt moved during construction of the Panama Canal. This material flowed down the rivers, progressively eroding into finer and finer sediment, until it reached the bay system. Here some of it settled, eventually filling in Suisun Bay, San Pablo Bay, and San Francisco Bay, in decreasing order of severity.
By the end of the 19th century, these "slickens" had filled in much of the shallow bay flats, raising the entire bay profile. New marshes were created in some areas.
In the decades surrounding 1900, at the behest of local political officials and following Congressional orders, the U.S. Army Corps began dredging the Sacramento and San Joaquin Rivers and the deep channels of San Francisco Bay. This work has continued without interruption ever since. Some of the dredge spoils were initially dumped in the bay shallows (including helping to create
Large ships transiting the bay must follow deep underwater channels that are maintained by frequent dredging as the average depth of the bay is only as deep as a swimming pool—approximately 12 to 15 ft (4–5 m). Between Hayward and San Mateo to San Jose it is 12 to 36 in (30–90 cm). The deepest part of the bay is under and out of the Golden Gate Bridge, at 372 ft (113 m).[42]
In the late 1990s, a 12-year harbor-deepening project for the
Transportation
San Francisco Bay was traversed by watercraft before the arrival of Europeans. Indigenous peoples used canoes to fish and clam along the shoreline. Sailing ships enabled transportation between the bay and other parts of the world—and served as ferries and freighters within the bay and between the bay and inland ports, such as Sacramento and Stockton. These were gradually replaced by steam-powered vessels starting in the late 19th century. Several shipyards were established around the bay, augmented during wartime (e.g., the Kaiser Shipyards, Richmond Shipyards) near Richmond in 1940 for World War II for construction of mass-produced, assembly line Liberty and Victory cargo ships.
San Francisco Bay is spanned by nine bridges, eight of which carry cars.
- The Richmond–San Rafael Bridge on Interstate 580 (I-580) connects Marin and Contra Costa counties.
- The Golden Gate Bridge on U.S. Route 101/State Route 1 (US 101/SR 1) was the largest single span suspension bridge ever built at the time of its 1937 construction. It spans the Golden Gate, the strait between San Francisco and Marin County, and is the only bridge in the area not owned by the State of California.
- The San Francisco–Oakland Bay Bridge on I-80 connects Alameda and San Francisco counties.
- The San Mateo–Hayward Bridge on SR 92 connects Alameda and San Mateo counties.
- The Dumbarton Bridge on SR 84 connects Alameda and San Mateo counties.
- The Carquinez Bridge (including the Alfred Zampa Memorial Bridge) on I-80 connects Contra Costa and Solano counties.
- The Benicia Bridge on I-680also connects Contra Costa and Solano counties.
- The Antioch Bridge on SR 160 connects Contra Costa and Sacramento counties.
- The Dumbarton Rail Bridge is an abandoned bridge that used to carry rail traffic.
The Transbay Tube, an underwater rail tunnel, carries BART services between Oakland and San Francisco.
Prior to the bridges and, later, the Transbay Tube, transbay transportation was dominated by fleets of
The bay also continues to serve as a major seaport. The Port of Oakland is one of the largest cargo ports in the United States, while the Port of Richmond and the Port of San Francisco provide smaller services.
An additional crossing south of the Bay Bridge has long been proposed.
Recreation
San Francisco Bay is a mecca for sailors (boats, as well as
The California Office of Environmental Health Hazard Assessment (OEHHA) has developed a safe eating advisory for fish caught in the San Francisco Bay based on levels of mercury or PCBs found in local species.[48]
The San Francisco Bay Area Water Trail is a planned system of designated trailheads designed to improve non-motorized small boat access to the bay. The California Coastal Conservancy approved funding in March 2011 to begin implementation of the water trail.
Gallery
|
See also
- Golden Gate
- Golden Gate Bridge
- Hydrography of the San Francisco Bay Area
- Islands of San Francisco Bay
- J.C. Barthel, who prepared "plans for the docks and other water-front improvements in the San Francisco Bay district"
- McLaughlin Eastshore State Park
- Mount Diablo
- Mount Tamalpais State Park
- Napa Sonoma Marsh
- Point Pinole Regional Shoreline, Richmond
References
- ^ "San Francisco Bay". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. January 19, 1981. Retrieved January 2, 2017.
- ^ "Anatomy of the Bay: 7 bites of San Francisco Bay history, science, and lore". July 6, 2016. Retrieved May 24, 2023.
- ^ "San Francisco Bay/Estuary (SFBE)". Ramsar Sites Information Service. Retrieved April 25, 2018.
- ^ "Symphonies in Steel: San Francisco – Oakland Bay Bridge and the Golden Gate".
- ^ San Francisco Bay Watershed Database and Mapping Project Archived October 30, 2004, at the Wayback Machine
- ^ "BCDC - The San Francisco Bay Estuary". bcdc.ca.gov. Retrieved February 14, 2022.
- ^ "The Formation of San Francisco Bay" (PDF). KQED education. Retrieved June 4, 2018.
- ^ Yabrove, Daniel (December 9, 2013). "How the Bay was Born". Save The Bay Blog. Save The Bay. Retrieved June 4, 2018.
- ^ Olmsted, Nancy J. "Water on the Land—The Coast People". FoundSF. Retrieved June 4, 2018.
- ^ Aker, Raymond (1970). REPORT OF FINDINGS RELATING TO THE IDENTIFICATION OF SIR FRANCIS DRAKE'S ENCAMPMENT AT POINT REYES NATIONAL SEASHORE (PDF). pp. 338–340.
- ^ Charles F. Lumis, ed. (1900). "Narrative of the Pilot Morera, who passed through the North Sea to the South Sea through the Strait". The Land of Sunshine, the Magazine of California and the West. No. February. pp. 184–186.
- S2CID 128670900.
- ^ "Group of men standing around original shoreline tablet". delivery.library.ca.gov. San Francisco, California. 1921. Retrieved October 6, 2021.
- ^ Alta California, September 7, 1869
- ^ "Cprr.org".
- ^ Schneider, E. J. (January 1913). "Construction Problems, Dumbarton Bridge, Central California Railway". Proceedings of the American Society of Civil Engineers. 39 (1): 117–128. Retrieved March 14, 2016.
- ISBN 0-520-08878-6. Retrieved March 15, 2016.
- ^ "The old Dumbarton Bridge: Did you see it fall into the bay?". January 17, 2017.
- ^ The Barrier Broken – Vallejo Evening Chronicle, May 21, 1927
- ^ "Two Bay Area Bridges". U.S. Department of Transportation. January 18, 2005. Archived from the original on October 11, 2009. Retrieved June 13, 2008.
- ^ "Key Dates - Moments & Events | Golden Gate". www.goldengate.org.
- ^ "Frisco Adds Another Bridge To Skyline". Sarasota Herald-Tribune. August 16, 1956. Retrieved March 1, 2016.
- ^ "San Mateo–Hayward Bridge Facts". California Department of Transportation. 1995. Retrieved January 14, 2015.
- ^ "Sylvia McLaughlin: Citizen Activist for the Environment: Saving San Francisco Bay, Promoting Shoreline Parks and Natural Values in Urban and Campus Planning". Oral History Center, Bancroft Library. University of California. 2009. Retrieved February 28, 2023.
- ^ "History". Save the Bay. Retrieved July 14, 2015.
- ^ "Bay Area Census". www.bayareacensus.ca.gov. Retrieved October 31, 2018.
- ^ State Water Resources Control Board Water Quality Control Policy for the Enclosed Bays and Estuaries of California (1974) State of California
- ^ "Spatial History Project".
- ^ "Hidden Ecologies » Blog Archive » Arden Salt Works". November 17, 2005.
- ^ "Salt Marsh Harvest Mouse" (PDF). South Bay Salt Pond Restoration Project. Archived (PDF) from the original on March 20, 2017. Retrieved September 25, 2019.
- ^ Osborn, Liz. "Average Ocean Water Temperatures at San Francisco". Current Results Nexus. Retrieved October 19, 2013.
- ^ David Perlman (November 8, 2010). "Porpoises return to SF Bay – scientists study why". San Francisco Chronicle. Retrieved July 25, 2011.
- ^ "Harbor Porpoise Project". Golden Gate Cetacean Research. Retrieved July 25, 2011.
- ^ Harbor Porpoise (Phocoena phocoena): San Francisco-Russian River Stock (PDF) (Report). National Marine Fisheries Service. October 15, 2009. Retrieved July 25, 2011.
- S2CID 255918023.
- )
- ^ Bailey, Eric (November 9, 2007). "Oil oozes in S.F. Bay after ship hits bridge". Los Angeles Times. Archived from the original on March 22, 2019.
- ^ Nutrient Status of San Francisco Bay and Its Management Implications. Vol. 43. 2020. pp. 1299–1317.
{{cite book}}
:|journal=
ignored (help) - ^ Liz Kreutz. "Harmful algae bloom spreading across San Francisco Bay, turning water brown". ABC7 News.
- ^ "Corkscrew Slough". Geographic Names Information System. United States Geological Survey, United States Department of the Interior.
- PMID 30366322. Retrieved March 16, 2019.
- . Retrieved January 2, 2017.
- ^ Sandifur, Marilyn (September 18, 2009). "50 Feet Delivered!". Port of Oakland. Retrieved January 3, 2017.
- ^ United States. Army. Corps of Engineers. San Francisco District, Port of Oakland (1998). Oakland harbor navigation improvement (−50-foot) project: draft environmental impact statement/environmental impact report: executive summary. U.S. Army Corps of Engineers, San Francisco District.
- ^ "USA: Port of Oakland Secures USD 18 Million in Federal Funding for Dredging Project". Dredging Today. June 1, 2011. Retrieved March 22, 2012.
- ^ "USA: Congresswoman Helps Oakland Port Reach Major Funding Milestone for Deepening Project". Dredging Today. March 21, 2012. Retrieved March 22, 2012.
- ^ Matthews, Mark (March 22, 2012). "Huge container ship cruises into Port of Oakland". ABC7. San Francisco: KGO-TV/DT. Retrieved March 23, 2012.
- ^ Admin, OEHHA (December 30, 2014). "San Francisco Bay". OEHHA. Retrieved June 13, 2018.
Literature
- The Bay of San Francisco: The metropolis of the Pacific Coast and its suburban cities: A history. Volume I. Lewis Publishing Company, Chicago, Ill. Published 1892. Contains index to biographical sketches
- Volume II – Biographies
External links
- San Francisco Bay: Portrait of an Estuary, David Sanger and John Hart, University of California Press
- Barging In – A Short History of Liveaboards on the Bay Archived August 19, 2018, at the Wayback Machine
- The Islands of San Francisco Bay, James A. Martin | Michael T. Lee, Down Window Press
- Army Corps of Engineers Bay Model: Working scale model of the Bay
- SF Bay Kayak, Canoe, and Boat Launch Ramp guide. A collaboratively edited guide to the SF bay.
- BoatingSF.com: Photos of SF Bay and its boats, plus online cruising guide
- Save San Francisco Bay: Protect and Restore San Francisco Bay
- sfbaywildlife.info Guide to San Francisco Bay wildlife
- Early History of the California Coast, a National Park Service Discover Our Shared Heritage Travel Itinerary
- Cartography & History The representations of San Francisco Bay: a portable harbor in the fragile geography of the North Pacific
- San Francisco Estuary and Watershed Science: a peer-reviewed online science journal