|
San Gabriel Dam
San Gabriel Dam is a rock-fill dam on the San Gabriel River in Los Angeles County, California, within the Angeles National Forest. Completed in 1939, the dam impounds the main stem of the San Gabriel River about downstream from the confluence of the river's East and West Forks, which drain a large portion of the San Gabriel Mountains. It is located directly upstream from the Morris Dam. The dam provides flood control, groundwater recharge flows and hydroelectricity for the heavily populated San Gabriel Valley in the Greater Los Angeles metropolitan area. History In the 1920s, the Los Angeles County Flood Control District proposed to impound the San Gabriel River just below the confluence of the East and West forks with a high, long concrete arch dam to capture floods and provide water conservation. To be named the San Gabriel Forks Dam, the project was canceled by the State Engineer after having convened an inquiry to investigate problems which were occurring at San Gabriel Da ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles County, California
Los Angeles County, officially the County of Los Angeles, and sometimes abbreviated as L.A. County, is the List of the most populous counties in the United States, most populous county in the United States and in the U.S. state of California, with 9,861,224 residents estimated as of 2022. It is the most populous non–State (United States), state-level government entity in the United States. Its population is greater than that of 40 individual List of U.S. states and territories by population, U.S. states. At and with List of cities in Los Angeles County, California, 88 incorporated cities and List of unincorporated communities in Los Angeles County, California, many unincorporated areas, it is home to more than one-quarter of California residents and is one of the most ethnically diverse counties in the United States. Its county seat, Los Angeles, is also California's most populous city and the second-most populous city in the United States, with about 3.9 million residents. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Depression
The Great Depression (19291939) was an economic shock that impacted most countries across the world. It was a period of economic depression that became evident after a major fall in stock prices in the United States. The economic contagion began around September and led to the Wall Street stock market crash of October 24 (Black Thursday). It was the longest, deepest, and most widespread depression of the 20th century. Between 1929 and 1932, worldwide gross domestic product (GDP) fell by an estimated 15%. By comparison, worldwide GDP fell by less than 1% from 2008 to 2009 during the Great Recession. Some economies started to recover by the mid-1930s. However, in many countries, the negative effects of the Great Depression lasted until the beginning of World War II. Devastating effects were seen in both rich and poor countries with falling personal income, prices, tax revenues, and profits. International trade fell by more than 50%, unemployment in the U.S. rose to 23% and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kilowatt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Watt (1736–1819), an 18th-century Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own steam engine in 1776. Watt's invention was fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one metre per second against a constant opposing force of one newton, the rate at which work is done is one watt. : \mathrm In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical circuit). : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whittier Narrows Dam
Whittier Narrows Dam is a 56-foot (17 m) tall earth dam on the San Gabriel River and the smaller, parallel Rio Hondo. The dam is located, as the name implies, at the Whittier Narrows. It provides water conservation storage and is also the central element of the Los Angeles County Drainage Area (LACDA) flood control system. Its reservoir has a capacity of . The Whittier Narrows are a natural gap in the hills that form the southern boundary of the San Gabriel Valley of Southern California. Both the Rio Hondo, a tributary of the Los Angeles River, and the San Gabriel River flow through this gap and are impounded by the reservoir. The Pomona Freeway (CA-60) passes through the reservoir flood control basin and the San Gabriel River Freeway (I-605) passes along the eastern boundary of the basin. In September 2017, the United States Army Corps of Engineers officials warned local residents that the dam no longer met the agency’s 'tolerable-risk' guidelines and could fail in the eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Santa Fe Dam
Santa Fe Dam is a flood-control dam on the San Gabriel River located in Irwindale in Los Angeles County, California, United States. For most of the year, the -high dam and its reservoir lie empty, but can hold more than of water during major storms. During the dry season, the basin behind the dam is used for groundwater recharge, as well as various recreational activities. History Construction of the dam began in 1941 under the U.S. Army Corps of Engineers (USACE), mainly in response to major floods on the river in 1938; however, work stopped in 1943 and did not resume again until 1946 due to the unlucky intervention of a major flood and World War II. The dam embankment and spillway were completed in early 1947, and the entire project was finished in January 1949 with the installation of the spillway gates, four months ahead of schedule. Santa Fe Dam Recreational Area The Los Angeles County Board of Supervisors passed a resolution in 1955 stating that the county wished to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
California Coastal Commission
The California Coastal Commission (CCC) is a state agency within the California Natural Resources Agency with quasi-judicial control of land and public access along the state's coastline. Its mission as defined in the California Coastal Act is "to protect, conserve, restore, and enhance the environment of the California coastline". Protection of coastal resources includes shoreline public access and recreation, lower cost visitor accommodations, terrestrial and marine habitat protection, visual resources, and regulation of agricultural lands, commercial fisheries, and industrial infrastructure. By regulating land use within a defined coastal zone extending inland from up to , it has the authority to control construction of any type, including buildings, housing, roads, as well as fire and erosion abatement structures, and can issue fines for unapproved construction. It has been called the single most powerful land-use authority in the United States due to its purview over vast e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beach Nourishment
Beach nourishment (also referred to as beach renourishment, beach replenishment, or sand replenishment) describes a process by which sediment, usually sand, lost through longshore drift or erosion is replaced from other sources. A wider beach can reduce storm damage to coastal structures by dissipating energy across the surf zone, protecting upland structures and infrastructure from storm surges, tsunamis and unusually high tides. Beach nourishment is typically part of a larger integrated coastal zone management aimed at coastal defense. Nourishment is typically a repetitive process since it does not remove the physical forces that cause erosion but simply mitigates their effects. The first nourishment project in the United States was at Coney Island, New York in 1922 and 1923. It is now a common shore protection measure used by public and private entities. History The first nourishment project in the U.S. was constructed at Coney Island, New York in 1922–1923. Before ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentation
Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration, or electromagnetism. Settling is the falling of suspended particles through the liquid, whereas sedimentation is the final result of the settling process. In geology, sedimentation is the deposition of sediments which results in the formation of sedimentary rock. The term is broadly applied to the entire range of processes that result in the formation of sedimentary rock, from initial erosion through sediment transport and settling to the lithification of the sediments. However, the strict geological definition of sedimentation is the mechanical deposition of sediment particles from an initial suspension in air or water. Sedimentation may pertain to ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arcadia, California
Arcadia is a city in Los Angeles County, California, United States, located about northeast of downtown Los Angeles in the San Gabriel Valley and at the base of the San Gabriel Mountains. It contains a series of adjacent parks consisting of the Santa Anita Park racetrack, the Los Angeles County Arboretum and Botanic Garden, and Arcadia County Park. The city had a population of 56,364 at the 2010 census, up from 53,248 at the 2000 census. The city is named after Arcadia, Greece. History Native American For over 8,000 years, the site of Arcadia was part of the homeland of the Tongva people ("Gabrieliño" tribe), a Californian Native American tribe whose territory spanned the greater Los Angeles Basin, and the San Gabriel and San Fernando Valleys. Their fluid borders stretched between the Santa Susana Mountains, San Bernardino Mountains, and San Gabriel Mountains in the north; the Santa Monica Mountains and Simi Hills in the west; the San Jacinto Mountains and Santa Ana Mounta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spreading Ground
A spreading ground is a water conservation facility that retains surface water long enough for it to percolate into the soil. Spreading grounds must be located where underlying soils are permeable and connected to a target aquifer. Locating them above silt or clay would prevent the surface water from reaching formations that store water. When natural percolation of precipitation is insufficient to replenish groundwater withdrawn for human use, artificial recharge helps prevent aquifer depletion, subsidence and saltwater intrusion. Spreading grounds are one of several available technologies, and are useful to harness storm water runoff in populated areas with low annual precipitation. For example, Los Angeles County, California has 27 such facilities, and four more operated in conjunction with the department, many of which date to the 1930s. While managed aquifer recharge (MAR) projects utilizing storm water and diverted surface water runoff augment groundwater recharge, data s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles Flood Of 1938
The Los Angeles flood of 1938 was one of the largest floods in the history of Los Angeles, Orange, and Riverside Counties in southern California. The flood was caused by two Pacific storms that swept across the Los Angeles Basin in February-March 1938 and generated almost one year's worth of precipitation in just a few days. Between 113–115 people were killed by the flooding. The Los Angeles, San Gabriel, and Santa Ana Rivers burst their banks, inundating much of the coastal plain, the San Fernando and San Gabriel Valleys, and the Inland Empire. Flood control structures spared parts of Los Angeles County from destruction, while Orange and Riverside Counties experienced more damage. The flood of 1938 is considered a 50-year flood. It caused $78 million of damage ($ in dollars), making it one of the costliest natural disasters in Los Angeles' history. In response to the floods, the U.S. Army Corps of Engineers and other agencies began to channelize local streams in concrete, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Arcadia, California")
.jpg "Click for more on -> Los Angeles Flood Of 1938")