Ecology of the San Francisco Estuary
The San Francisco Estuary together with the Sacramento–San Joaquin River Delta represents a altered ecosystem. The region has been re-engineered to accommodate the needs of water delivery, shipping and most suburban development; these needs have wrought direct changes in the movement of water and the nature of the landscape, indirect changes from the introduction of non-native species. New species have altered the architecture of the food web as as levees have altered the landscape of islands and channels that form the complex system known as the Delta; this article deals with the ecology of the low salinity zone of the estuary. Reconstructing a historic food web for the LSZ is difficult for a number of reasons. First, there is no clear record of the species that have occupied the estuary. Second, the San Francisco Estuary and Delta have been in geologic and hydrologic transition for most of their 10,000 year history, so describing the "natural" condition of the estuary is much like "hitting a moving target".
Climate change, hydrologic engineering, shifting water needs, newly introduced species will continue to alter the food web configuration of the estuary. This model provides a snapshot of the current state, with notes about recent changes or species introductions that have altered the configuration of the food web. Understanding the dynamics of the current food web may prove useful for restoration efforts to improve the functioning and species diversity of the estuary; the San Francisco Bay is both an estuary. The former term refers to any cove providing a physical refuge from the open ocean. An estuary is any physiographic feature where freshwater meets an sea; the northern portion of the bay is a brackish estuary, consisting of a number of physical embayments which are dominated by both marine and fresh water fluxes. These geographic entities are, moving from saline to fresh: San Pablo Bay north of the Central Bay; until the 20th century, the LSZ of the estuary was fringed by tule-dominated freshwater wetlands.
Between 80-95% of these historic wetlands have been filled to facilitate land use and development around the Bay Area. Habitat loss at the edges of the pelagic zone is thought to create a loss of native pelagic fish species, by increasing vulnerability to predation; the intertidal and benthic estuary is presently dominated by mudflats that are the result of sedimentation derived from gold mining in the Sierra Nevada in the late 19th century. The trend toward high sediment loads was reversed in the 1950s with the advent of the Central Valley Project, locking up most sediment behind dams, resulting in an annual net loss of sediments from the estuary, thus the mudflats appear to be receding, although turbidity remains high. The high turbidity of the water is responsible for the unique condition that exists in the San Francisco Estuary wherein high nutrient availability does not lead to high phytoplankton production. Instead, most algae photosynthetic organisms are light-limited; the Delta has experienced heavy alteration.
Beginning in the 19th century occurring levees were reinforced for permanency, to protect farmlands from regular flooding. Many of these farms were established on peat islands occurring in the middle of the Delta waterways. Intensive farming oxidized the high carbon content of the soil, causing considerable loss of soil mass; as a consequence, these islands have sunk, to nearly 6 meters below sea level. The Delta today consists of riprapped waterways, punctuated by islands that appear like "floating bowls" with their basins far below the surface of the water; these islands are at high risk for flooding due to levee collapse. The subsequent eastward shift in salinity is expected to alter the ecology of the entire LSZ of the San Francisco Estuary; the LSZ centers around ranges from about 6 psu down to 0.5 psu. The primary fresh water inputs to the estuary derive from runoff of regional precipitation, the Sacramento River, the San Joaquin River. River inflow is controlled by upstream reservoir releases.
A significant fraction of this inflow is exported out of the Delta by the federal Central Valley Project and the State Water Project to southern California for agricultural and urban use. These alterations have removed much of the variation in through-estuary outflow, creating lower outflow in the winter and higher outflow in the summer than found in the estuary. On average, freshwater flows into the estuary are 50% of historic flows. Phytoplankton and larval and adult fish can become entrained in the export pumps, causing a significant but unknown impact on the abundance of these organisms; this may be true of the endangered delta smelt, a small endemic fish. The delta smelt is believed to migrate and spawn upstream in the Delta during the early summer, placing its eggs and larvae at high risk for entrainment. Management for the smelt is the source of controversy as its ecology brings into collision course the disparate water needs of conservation and agriculture in California; the movement of water out of the estuary is dependent upon a number of factors.
Tidal cycles cause water to move toward and away from the Golden Gate four times in a 24-hour period. Using 2 psu as a marker for the Low Salinity Zon
San Joaquin River
The San Joaquin River is the longest river of Central California in the United States. The 366-mile long river starts in the high Sierra Nevada, flows through the rich agricultural region of the northern San Joaquin Valley before reaching Suisun Bay, San Francisco Bay, the Pacific Ocean. An important source of irrigation water as well as a wildlife corridor, the San Joaquin is among the most dammed and diverted of California's rivers. People have inhabited the San Joaquin Valley for more than 8,000 years, it was long one of the major population centers of pre-Columbian California. Starting in the late 18th century, successive waves of explorers settlers Spanish and American, emigrated to the San Joaquin basin, first exploiting driving out the indigenous tribes; the newcomers appropriated the rich natural and hydrologic resources of the watershed for use in farms and cities, but found themselves plagued by flood and drought. Because of the uniform topography of the San Joaquin Valley, floods once transformed much of the lower river into a huge inland sea.
In the 20th century, many levees and dams were built on the San Joaquin and all of its major tributaries. These engineering works changed the fluctuating nature of the river forever, cut off the Tulare Basin from the rest of the San Joaquin watershed. Once habitat for hundreds of thousands of spawning salmon and millions of migratory birds, today the river is subject to tremendous water-supply and regulation works by various federal agencies, which have reduced the flow of the river since the 20th century; the river was called many different names. The present name of the river dates to 1805–1808, when Spanish explorer Gabriel Moraga was surveying east from Mission San José in order to find possible sites for a mission. Moraga named a tributary of the river for Saint Joachim, husband of Saint Anne and father of Mary, the mother of Jesus; the name Moraga chose was applied to the entire river. In 1827, Jedediah Smith wrote in his journal that an unknown group of Native Americans called the river the Peticutry, a name, listed as an official variant in the U.
S. Geological Survey Geographic Names Information System. In the Mono language, the river is called typici h huu', which means "important or great river."An earlier name for the lower section of the San Joaquin was Rio de San Francisco, the name Father Juan Crespí gave to the river he could see entering the Sacramento-San Joaquin Delta from the south. A member of the Pedro Fages party in 1772, Crespi's vantage point was the hilltops behind modern Antioch. Another early name was Rio San Juan Bautista, the origin of, unknown; the river's source is located in the Ansel Adams Wilderness, in the south-central Sierra Nevada at the confluence of two major affluents: the Middle Fork, which rises from Thousand Island Lake at 10,000 ft above sea level, the smaller North Fork, which starts 1.8 mi southeast of Mount Lyell. The Middle Fork is considered part of the main stem; the South Fork, which begins at Martha Lake in Kings Canyon National Park and flows through Florence Lake, joins a short distance downstream.
From the mountainous alpine headwaters, the San Joaquin flows south into the foothills of the Sierra, passing through four hydroelectric dams. It emerges from the foothills at what was once the town of Millerton, the location of Friant Dam since 1942, which forms Millerton Lake. Below Friant Dam, the San Joaquin flows west-southwest out into the San Joaquin Valley – the southern part of the Great Central Valley – passing north of Fresno. With most of its water diverted into aqueducts, the river runs dry in a 150-mile section; this lack of riverwater begins in the 60 mi between Friant Dam and Mendota, where it is only replenished by the Delta-Mendota Canal and the Fresno Slough, when the Kings River is flooding. From Mendota, the San Joaquin swings northwest, passing through many different channels, some natural and some man-made. Northeast of Dos Palos, it is only joined by the Fresno and Chowchilla Rivers when they reach flood stage. Fifty miles downstream, the Merced River empties into an otherwise dry San Joaquin.
The majority of the river flows through quiet agricultural bottom lands, as a result its meandering course manages to avoid most of the urban areas and cities in the San Joaquin Valley. About 11 mi west of Modesto, the San Joaquin meets the Tuolumne. Near Vernalis, it is joined by the Stanislaus River; the river passes between Manteca and Tracy, where a pair of distributaries – the Old River and Middle River – split off from the main stem just above the Sacramento-San Joaquin Delta, a huge inverted river delta formed by sediment deposits of the Sacramento and San Joaquin Rivers. About 40 mi from the mouth, the river draws abreast to the western flank of Stockton, one of the basin's largest cities. From here to the mouth, the river is dredged as part of a navigation project, the Stockton Deep Water Ship Channel. Past the head of tide, amid the many islands of the delta, the San Joaquin is joined by two more tributaries: the Calaveras River and the larger Mokelumne; the river grows to 5,000 ft wide before ending at its confluence with the Sacramento River, in Antioch, forming the head of Suisun Bay.
The combined waters from the two rivers flow west through the Carquinez Strait and San Francisco Bay into the Pacific. The natural annual discharge of the San Joaquin before agricultural development is believed to ha
1989 Loma Prieta earthquake
The 1989 Loma Prieta earthquake occurred in Northern California on October 17 at 5:04 p.m. local time. The shock was centered in The Forest of Nisene Marks State Park 10 mi 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 Mw magnitude of 6.9 and a maximum Modified Mercalli intensity of IX, the shock was responsible for 63 deaths and 3,757 injuries. The Loma Prieta segment of the San Andreas Fault System had been inactive since the 1906 San Francisco earthquake 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 faulting occurred, though a large number of other ground failures and landslides were present in the Summit area of the Santa Cruz Mountains.
Liquefaction was a significant issue in the damaged Marina District of San Francisco, but its effects were seen in the East Bay, near the shore of Monterey Bay, where a non-destructive tsunami was observed. Due to the sports coverage of the 1989 World Series, it became the first major earthquake in the United States, broadcast live on national television. Rush-hour traffic on the Bay Area freeways was lighter than normal because the game, being played at Candlestick Park in San Francisco, was about to begin, this may have prevented a larger loss of life, as several of the Bay Area's major transportation structures suffered catastrophic failures; the collapse of a section of the double-deck Nimitz Freeway in Oakland was the site of the largest number of casualties for the event, but the collapse of man-made structures and other related accidents contributed to casualties occurring in San Francisco, Los Altos, Santa Cruz. The history of earthquake investigations in California has been focused on the San Andreas Fault System, due to its strong influence in the state as the boundary between the Pacific Plate and the North American Plate.
Andrew Lawson, a geologist from the University of California, had named the fault after the San Andreas Lake and led an investigation into that event. The San Andreas Fault ruptured for a length of 290 mi during the 1906 shock, both to the north of San Francisco and to the south in the Santa Cruz Mountains region. Several long term forecasts for a large shock along the San Andreas Fault in that area had been made public prior to 1989 but the earthquake that transpired was not what had been anticipated; the 1989 Loma Prieta event originated on an undiscovered oblique-slip reverse fault, located adjacent to the San Andreas Fault. Since many forecasts had been presented for the region near Loma Prieta, seismologists were not taken by surprise by the October 1989 event. Between 1910 and 1989 there were 20 varying forecasts that were announced, with some that were specific, covering multiple aspects of an event, while others were less complete and vague. With a M6.5 event on the San Juan Bautista segment, or an M7 event on the San Francisco Peninsula segment, United States Geological Survey seismologist Allan Lindh's 1983 forecasted rupture length of 25 miles for the San Juan Bautista segment nearly matched the actual rupture length of the 1989 event.
An updated forecast was presented in 1988, at which time Lindh took the opportunity to assign a new name to the San Juan Bautista segment – the Loma Prieta segment. In early 1988, the Working Group for California Earthquake Probabilities made several statements regarding their forecasts for the 225 mi northern San Andreas Fault segment, the 56 mi San Francisco Peninsula segment, a 18.8–22 mi portion of that segment, referred to as the southern Santa Cruz Mountains segment. The thirty year probability for one or more M7 earthquakes in the study area was given as 50%, but because of a lack of information and low confidence, a 30% probability was assigned to the Southern Santa Cruz Mountains segment. Two moderate shocks, referred to as the Lake Elsman earthquakes by the USGS, occurred in the Santa Cruz Mountains region in June 1988 and again in August 1989. Following each event, the State office of Emergency Services issued short term advisories for a possible large earthquake, which meant there was "a increased likelihood of an M6.5 event on the Santa Cruz Mountains segment of the San Andreas fault".
The advisories following the two Lake Elsman events were issued in part because of the statements made by WGCEP and because they were two of the three largest shocks to occur along the 1906 earthquake's rupture zone since 1914. The ML 5.3 June 1988 and the ML 5.4 August 1989 events occurred on unknown oblique reverse faults and were within 3 mi of the M6.9 Loma Prieta mainshock epicenter, near the intersection of the San Andreas and Sargent faults. Total displacement for these shocks was small and although they occurred on separate faults and well before the mainshock, a group of seismologists considered these to be foreshocks due to their location in sp
Park Street Bridge
The Park Street Bridge is a double-leaf bascule drawbridge spanning 372 feet of the Oakland Estuary in the San Francisco Bay Area. It links the cities of Alameda. In a year, the bridge is opened 1700 times and carries 40,000 vehicles per work day, it was built when the Oakland Estuary was trenched, converting Alameda from a peninsula to an island. The Park Street bridge is one of the four bridges, it is considered the best route for bicycles to cross to Alameda as the small narrow walkway in the Posey Tube is difficult to navigate if there is another pedestrian or bicyclist using it. The original Park Street bridge was completed in 1893; the Park Street, High Street, Fruitvale Avenue bridgess were built by the U. S. Government in exchange for permission and rights-of-way to dredge the channel between San Antonio Creek and San Leandro Bay, it had a wrought iron thru truss swing span and wooden trestle approach spans. Riding the bridge as it opened to let water traffic through, as well as fishing off the bridge, were popular activities.
It took ten years after the bridge's completion to dredge the channel. The present bridge was designed by the County of Alameda Surveyors Office and constructed under the Federal WPA Program, it was opened in 1935 with a grand opening celebration that included a public wedding of a man from Oakland and woman from Alameda to symbolize the unity of the two cities with the building of the bridge. Media related to Park Street bridge, California at Wikimedia Commons
United States Army Corps of Engineers
The United States Army Corps of Engineers is a U. S. federal agency under the Department of Defense and a major Army command made up of some 37,000 civilian and military personnel, making it one of the world's largest public engineering and construction management agencies. Although associated with dams and flood protection in the United States, USACE is involved in a wide range of public works throughout the world; the Corps of Engineers provides outdoor recreation opportunities to the public, provides 24% of U. S. hydropower capacity. The corps' mission is to "Deliver vital military engineering services. Other civil engineering projects include flood control, beach nourishment, dredging for waterway navigation. Design and construction of flood protection systems through various federal mandates. Design and construction management of military facilities for the Army, Air Force, Army Reserve and Air Force Reserve and other Defense and Federal agencies. Environmental regulation and ecosystem restoration.
The history of United States Army Corps of Engineers can be traced back to 16 June 1775, when the Continental Congress organized an army with a chief engineer and two assistants. Colonel Richard Gridley became General George Washington's first chief engineer. One of his first tasks was to build fortifications near Boston at Bunker Hill; the Continental Congress recognized the need for engineers trained in military fortifications and asked the government of King Louis XVI of France for assistance. Many of the early engineers in the Continental Army were former French officers. Louis Lebègue Duportail, a lieutenant colonel in the French Royal Corps of Engineers, was secretly sent to America in March 1777 to serve in Washington's Continental Army. In July 1777 he was appointed colonel and commander of all engineers in the Continental Army, in November 17, 1777, he was promoted to brigadier general; when the Continental Congress created a separate Corps of Engineers in May 1779 Duportail was designated as its commander.
In late 1781 he directed the construction of the allied U. S.-French siege works at the Battle of Yorktown. From 1794 to 1802 the engineers were combined with the artillery as the Corps of Artillerists and Engineers; the Corps of Engineers, as it is known today, came into existence on 16 March 1802, when President Thomas Jefferson signed the Military Peace Establishment Act whose aim was to "organize and establish a Corps of Engineers... that the said Corps... shall be stationed at West Point in the State of New York and shall constitute a military academy." Until 1866, the superintendent of the United States Military Academy was always an officer of engineer. The General Survey Act of 1824 authorized the use of Army engineers to survey canal routes; that same year, Congress passed an "Act to Improve the Navigation of the Ohio and Mississippi Rivers" and to remove sand bars on the Ohio and "planters, sawyers, or snags" on the Mississippi, for which the Corps of Engineers was the responsible agency.
Separately authorized on 4 July 1838, the U. S. Army Corps of Topographical Engineers consisted only of officers and was used for mapping and the design and construction of federal civil works and other coastal fortifications and navigational routes, it was merged with the Corps of Engineers on 31 March 1863, at which point the Corps of Engineers assumed the Lakes Survey District mission for the Great Lakes. In 1841, Congress created the Lake Survey; the survey, based in Detroit, Mich. was charged with conducting a hydrographical survey of the Northern and Northwestern Lakes and preparing and publishing nautical charts and other navigation aids. The Lake Survey published its first charts in 1852. In the mid-19th century, Corps of Engineers' officers ran Lighthouse Districts in tandem with U. S. Naval officers; the Army Corps of Engineers played a significant role in the American Civil War. Many of the men who would serve in the top leadership in this institution were West Point graduates who rose to military fame and power during the Civil War.
Some of these men were Union Generals George McClellan, Henry Halleck, George Meade, Confederate generals Robert E. Lee, Joseph Johnston, P. G. T. Beauregard; the versatility of officers in the Army Corps of Engineers contributed to the success of numerous missions throughout the Civil War. They were responsible for building pontoon and railroad bridges and batteries, the destruction of enemy supply lines, the construction of roads; the Union forces were not the only ones to employ the use of engineers throughout the war, on 6 March 1861, once the South had seceded from the Union, among the different acts passed at the time, a provision was included that called for the creation of a Confederate Corps of Engineers. The progression of the war demonstrated the South's disadvantage in engineering expertise. To overcome this obstacle, the Confederate Congress passed legislation that gave a company of engineers to every division in the field. One of the main projects for the Army Corps of Engineers was constructing railroads and bridges, which Union forces took advantage of because railroads and bridges provided access to resources and industry.
One area where the Confederate engineers were able to outperform the Union Army was in the ability to build fortification
Union Pacific Railroad
Union Pacific Railroad is a freight hauling railroad that operates 8,500 locomotives over 32,100 route-miles in 23 states west of Chicago and New Orleans. The Union Pacific Railroad system is the second largest in the United States after the BNSF Railway and is one of the world's largest transportation companies; the Union Pacific Railroad is the principal operating company of the Union Pacific Corporation. Union Pacific is known for pioneering multiple innovative locomotives the most powerful of their era; these include members of the Challenger-type, the Northern-type, as well as the famous Big Boy steam locomotives. Union Pacific ordered the first streamliner, the largest fleet of turbine-electric locomotives in the world, still owns the largest operational diesel locomotive; the Union Pacific legacy began in 1862 with the original company, called the Union Pacific Rail Road, part of the First Transcontinental Railroad project known as the Overland Route. The railroad would subsequently be reorganized thrice: as the Union Pacific Railway, as the Union Pacific "Railroad", as a renamed Southern Pacific Transportation Company.
The current Union Pacific corporation began in 1969 as the Southern Pacific Transportation Company, itself created in a reorganization of a railroad whose legacy dated to 1865. Over the years it would grow to include the Denver and Rio Grande Western Railroad and the St. Louis Southwestern Railway, in addition to its eponymous railroad; the 1998 Union Pacific-Southern Pacific merger was not UP's first: Union Pacific had merged with Missouri Pacific Railroad, the Chicago and North Western Transportation Company, the Western Pacific Railroad and the Missouri–Kansas–Texas Railroad. However, because the merger with Southern Pacific changed the scope of the Union Pacific railroad, this article will refer to the unmerged system as Union Pacific, the merged system as Union Pacific. Union Pacific's main competitor is the BNSF Railway, the nation's largest freight railroad by volume, which primarily services the Continental U. S. west of the Mississippi River. Together, the two railroads have a duopoly on all transcontinental freight rail lines in the U.
S. The original company, the Union Pacific Rail Road was incorporated on July 1, 1862, under an act of Congress entitled Pacific Railroad Act of 1862; the act was approved by President Abraham Lincoln, it provided for the construction of railroads from the Missouri River to the Pacific as a war measure for the preservation of the Union. It was constructed westward from Council Bluffs, Iowa to meet the Central Pacific Railroad line, constructed eastward from Sacramento, CA; the combined Union Pacific-Central Pacific line became known as the First Transcontinental Railroad and the Overland Route. The line was constructed by Irish labor who had learned their craft during the recent Civil War. Under the guidance of its dominant stockholder Dr. Thomas Clark Durant, the namesake of the city of Durant, the first rails were laid in Omaha; the two lines were joined together at Promontory Summit, Utah, 53 miles west of Ogden on May 10, 1869, hence creating the first transcontinental railroad in North America.
Subsequently, the UP purchased three Mormon-built roads: the Utah Central Railroad extending south from Ogden to Salt Lake City, the Utah Southern Railroad extending south from Salt Lake City into the Utah Valley, the Utah Northern Railroad extending north from Ogden into Idaho. The original UP was entangled in the Crédit Mobilier scandal, exposed in 1872; as detailed by The Sun, Union Pacific's largest construction company, Crédit Mobilier, had overcharged Union Pacific. In order to convince the federal government to accept the increased costs, Crédit Mobilier had bribed congressmen. Although the UP corporation itself was not guilty of any misdeeds, prominent UP board members had been involved in the scheme; the ensuing financial crisis of 1873 led to a credit crunch, but not bankruptcy. As boom followed bust, the Union Pacific continued to expand; the original company was purchased by a new company on January 24, 1880, with dominant stockholder Jay Gould. Gould owned the Kansas Pacific, sought to merge it with UP.
Thusly was the original "Union Pacific Rail Road" transformed into "Union Pacific Railway."Extending towards the Pacific Northwest, Union Pacific built or purchased local lines that gave it access to Portland, Oregon. Towards Colorado, it built the Union Pacific and Gulf Railway: both narrow gauge trackage into the heart of the Rockies and a standard gauge line that ran south from Denver, across New Mexico, into Texas; the Union Pacific Railway would declare bankruptcy during the Panic of 1893. Again, a new Union Pacific "Railroad" was formed and Union Pacific "Railway" merged into the new corporation. In the early 20th century, Union Pacific's focus shifted from expansion to internal improvement. Recognizing that farmers in the Central and Salinas Valleys of California grew produce far in excess of local markets, Union Pacific worked with its rival Southern Pacific to develop a rail-based transport system, not vulnerable to spoilage; these efforts came culminated in the 1906 founding of
Suisun Bay is a shallow tidal estuary in northern California. It lies at the confluence of the Sacramento and San Joaquin Rivers, forming the entrance to the Sacramento–San Joaquin River Delta, an inverted river delta. Suisun Marsh, the tidal marsh land to the north, is the largest marsh in California. Grizzly Bay forms a northern extension of Suisun Bay; the bay is directly north of Contra Costa County. The bay was named after the Suisunes, a Native American tribe of the area; the word originates with the Patwin. On the west, Suisun Bay is drained by the Carquinez Strait, which connects to San Pablo Bay, a northern extension of San Francisco Bay. In addition to the major bridges at the Carquinez Strait, it is spanned in its center by the Benicia-Martinez Bridge and at its eastern end by the State Route 160 crossing between Antioch and Oakley, it is the anchorage of the Suisun Bay Reserve Fleet, a collection of U. S. Navy and merchant reserve ships, created in the period following World War II; the Glomar Explorer was anchored here after recovering parts of a sunken Soviet submarine in the mid-1970s.
Many ships were sold for scrap in the 1990s. In 2010, plans were announced to remove the mothball fleet in stages, with final removal by 2017; the Central Pacific Railroad built a train ferry that operated between Benicia and Port Costa, California from 1879 to 1930. The ferry boats Solano and Contra Costa were removed from service when the nearby Martinez railroad bridge was completed in 1930. From 1913 until 1954 the Sacramento Northern Railway, an electrified interurban line, crossed Suisun Bay with the Ramon, a distillate-powered train ferry. On April 28, 2004, a petroleum pipeline operated by Kinder Morgan Energy Partners ruptured reported as spilling 1,500 barrels of diesel fuel in the marshes, this was updated to about 2,950 barrels. Kinder Morgan pleaded guilty to operating a corroded pipeline and paid three million dollars in penalties and restitution. Suisun Bay Reserve Fleet Kinder Morgan Information Regarding Pipeline Release Carl Nolte. "Suisun Bay's ghost fleet may R. I. P." SF Gate