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Van Norman Dams
The Van Norman Dams, also known as the San Fernando Dams, were the terminus of the Los Angeles Aqueduct, supplying about 80 percent of Los Angeles' water, until they were damaged in the 1971 San Fernando earthquake and were subsequently decommissioned due to the inherent instability of the site and their location directly above heavily populated areas. Construction The Upper Van Norman Dam initially was constructed with of hydraulic fill. In 1922, the dam was raised with rolled fill. The Lower Van Norman Dam was constructed with hydraulic and rolled fill. Hydraulic fill height was about , while rolled fill was added at least five times in the dam's history, each time increasing the dam's height, totaling rolled fill. The last addition was made in 1929–30. 1971 San Fernando earthquake The 1971 San Fernando earthquake significantly damaged the dams, resulting in evacuation of thousands of people from the San Fernando Valley immediately below. 80,000 were evacuated f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles County
Los Angeles County, officially the County of Los Angeles and sometimes abbreviated as LA County, is the most populous county in the United States, with 9,663,345 residents estimated in 2023. Its population is greater than that of 40 individual U.S. states. Comprising 88 incorporated cities and 101+ unincorporated areas within a total area of , it is home to more than a quarter of Californians and is one of the most ethnically diverse U.S. counties. The county's seat, Los Angeles, is the second most populous city in the United States, with 3,820,914 residents estimated in 2023. The county is the domicile of the U.S. motion picture industry since the latter's inception in the early 20th century. History Los Angeles County is one of the original counties of California, created at the time of statehood in 1850. The county originally included parts of what are now Kern, San Bernardino, Riverside, Inyo, Tulare, Ventura, and Orange counties. In 1851 and 1852, Los ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dams In Los Angeles County, California
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect or store water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions. The word ''dam'' can be traced back to Middle English, and before that, from Middle Dutch, as seen in the names of many old cities, such as Amsterdam and Rotterdam. Ancient dams were built in Mesopotamia and the Middle East for water control. The earliest known dam is the Jawa Dam in Jordan, dating to 3,000 BC. Egyptians also built dams, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1971 Earthquakes
* The year 1971 had three partial solar eclipses (Solar eclipse of February 25, 1971, February 25, Solar eclipse of July 22, 1971, July 22 and Solar eclipse of August 20, 1971, August 20) and two total lunar eclipses (February 1971 lunar eclipse, February 10, and August 1971 lunar eclipse, August 6). The world population increased by 2.1% this year, the highest increase in history. Events January * January 2 – 1971 Ibrox disaster: During a crush, 66 people are killed and over 200 injured in Glasgow, Scotland. * January 5 – The first ever One Day International cricket match is played between Australia and England at the Melbourne Cricket Ground. * January 8 – Tupamaros kidnap Geoffrey Jackson, British ambassador to Uruguay, in Montevideo, keeping him captive until September. * January 9 – Uruguayan president Jorge Pacheco Areco demands emergency powers for 90 days due to kidnappings, and receives them the next day. * January 12 – The landmark United States televis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dams Completed In 1921
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect or store water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions. The word ''dam'' can be traced back to Middle English, and before that, from Middle Dutch, as seen in the names of many old cities, such as Amsterdam and Rotterdam. Ancient dams were built in Mesopotamia and the Middle East for water control. The earliest known dam is the Jawa Dam in Jordan, dating to 3,000 BC. Egyptians also built dams, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earthquake And Seismic Risk Mitigation
An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume. In its most general sense, the word ''earthquake'' is used to describe any seismic event that generates seismic waves. Earthquakes can occur naturally or be induced by human activities, such as mining, fracking, and nuclear weapons testing. The initial point of rupture is called the hypocenter or focus, while the ground level directly above it is the epicen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reservoirs In California
A reservoir (; ) is an enlarged lake behind a dam, usually built to water storage, store fresh water, often doubling for hydroelectric power generation. Reservoirs are created by controlling a watercourse that drains an existing body of water, interrupting a watercourse to form an Bay, embayment within it, excavating, or building any number of retaining walls or levees to enclose any area to store water. Types Dammed valleys Dammed reservoirs are artificial lakes created and controlled by a dam constructed across a valley and rely on the natural topography to provide most of the basin of the reservoir. These reservoirs can either be ''on-stream reservoirs'', which are located on the original streambed of the downstream river and are filled by stream, creeks, rivers or rainwater that surface runoff, runs off the surrounding forested catchments, or ''off-stream reservoirs'', which receive water diversion, diverted water from a nearby stream or aqueduct (water supply), aq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Los Angeles County, California
The history of Los Angeles County, California includes the history of the Tovaangar; the pueblo, missions and ranchos of the Spanish-Mexican era; the histories of the various incorporated cities and unincorporated areas within the borders; and the story of the government of Los Angeles County. However, since statehood the boundaries of Los Angeles County have been changeable and beyond the vast administrative apparatus overseen by the L.A. County Board of Supervisors, the county was subdivided into minor civil divisions called townships. These townships were initially created under the Public Land Survey System but have functioned and been shaped quite differently than the rectangular townships of the Midwest or the township governments of New England. Boundaries of Los Angeles County Los Angeles County was one of the original counties established at the time of statehood. The eastern part of the original county was set aside in 1853 as San Bernardino County. In 1866 Kern Coun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Los Angeles
The modern history of Los Angeles began in 1781 when 44 settlers from central New Spain (modern Mexico) established a permanent settlement in what is now Downtown Los Angeles, as instructed by Spanish Governor of Las Californias, Felipe de Neve, and authorized by Viceroy Antonio María de Bucareli. After sovereignty changed from Mexico to the United States in 1849, great changes came from the completion of the Santa Fe railroad line from Chicago to Los Angeles in 1885. "Overlanders" flooded in, mostly white Protestants from the Midwest and Upland South. Los Angeles had a strong economic base in farming, oil, tourism, real estate and movies. It grew rapidly with many suburban areas inside and outside the city limits. Its motion picture industry made the city world-famous, and World War II brought new industry, especially high-tech aircraft construction. Politically the city was moderately conservative, with a weak labor union sector. Since the 1960s, growth has slowed—an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dam Failures In The United States
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect or store water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions. The word ''dam'' can be traced back to Middle English, and before that, from Middle Dutch, as seen in the names of many old cities, such as Amsterdam and Rotterdam. Ancient dams were built in Mesopotamia and the Middle East for water control. The earliest known dam is the Jawa Dam in Jordan, dating to 3,000 BC. Egyptians also built dams, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles Department Of Water And Power
The Los Angeles Department of Water and Power (LADWP) is the largest municipal Public utility, utility in the United States with 8,100 megawatts of electric generating capacity (2021–2022) and delivering an average of 435 million gallons of water per day (487,000 acre-ft per year) to more than four million residents and local businesses in the City of Los Angeles and several adjacent cities and communities in southwestern Los Angeles County, California. It was founded in 1902 to supply water to residents and businesses in the city of Los Angeles and several of its immediately adjacent communities. In 1917, LADWP began to deliver electric power, electricity to portions of the city. It has been involved in a number of controversies and media portrayals over the years, including the 1928 St. Francis Dam failure and the books ''Water and Power'' and ''Cadillac Desert''. History Private operators By the middle of the 19th century, Los Angeles's rapid population growth magnified p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
