Misplaced Pages

#302697

48-536: 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. The Upper Van Norman Dam initially

96-698: A cement plant in Monolith, California , which could produce 1,200 barrels of Portland cement per day. Regrinding mills were also built and operated by the city at the tufa quarries. To move 14 million ton-miles of freight, the city contracted with Southern Pacific to build a 118 mile long rail system from the Monolith mills to Olancha. The number of men who were on the payroll the first year was 2,629 and this number peaked at 6,060 in May 1909. In 1910, employment dropped to 1,150 due to financial reasons but rebounded later in

144-579: A form of travertine . It is generally thought that such features form from CaCO 3 precipitated when carbonate rich source waters emerge into alkaline soda lakes. They have also been found in marine settings in the Ikka fjord of Greenland where the Ikaite columns can reach up to 18 m (59 ft) in height. Tufa deposits form an important habitat for a diverse flora. Bryophytes (mosses, liverworts etc.) and diatoms are well represented. The porosity of

192-523: A form of calcareous sinter. They lack any significant macrophyte component due to the absence of light, and for this reason they are often morphologically closer to travertine or calcareous sinter. Tufa columns are an unusual form of tufa typically associated with saline lakes . They are distinct from most tufa deposits in that they lack any significant macrophyte component, due to the salinity excluding mesophilic organisms . Some tufa columns may actually form from hot-springs, and may therefore constitute

240-446: A large landslide fell into the reservoir along with 30 feet (9.1 m) of the crest and upstream face reducing the freeboard to about 5 feet (1.5 m). This failure was predominantly due to liquefaction of the hydraulic fill. To reduce the risk of catastrophic failure, the water level was lowered as rapidly as possible, 13.5 feet (4.1 m) in 3 + 1 ⁄ 2 days, at the rate of 700 cubic feet per second (20 m/s). This rate

288-652: A large project as the Colorado River Aqueduct despite the fact that they had built the Los Angeles Aqueduct. After the collapse, the pace of annexation came to a rapid halt when eleven nearby cities including Burbank, Glendale, Pasadena, Beverly Hills, San Marino, Santa Monica, Anaheim, Colton, Santa Ana, and San Bernardino decided to form the Metropolitan Water District with Los Angeles. The city's growth following

336-417: A reduction in p CO 2 , for example increased air-water interactions at waterfalls may be important, as may photosynthesis. Recently it has been demonstrated that microbially induced precipitation may be more important than physico-chemical precipitation. Pedley et al. (2009) showed with flume experiments that precipitation does not occur unless a biofilm is present, despite supersaturation. Calcite

384-537: Is disagreement over the actions of the " syndicate " as to whether they were a "diabolical" cabal or only a group that united the Los Angeles business community behind supporting the aqueduct, Eaton, Mulholland and others connected with the project have long been accused of using deceptive tactics and underhanded methods to obtain water rights and block the Bureau of Reclamation from building water infrastructure for

432-555: Is sometimes referred to as meteogene travertine . Modern and fossil tufa deposits abound with wetland plants; as such, many tufa deposits are characterised by their large macrobiological component, and are highly porous. Tufa forms either in fluvial channels or in lacustrine environments. Ford and Pedley (1996) provide a review of tufa systems worldwide. Deposits can be classified by their depositional environment (or otherwise by vegetation or petrographically ). Pedley (1990) provides an extensive classification system, which includes

480-574: Is the dominant mineral precipitate, followed by the polymorph aragonite . Tufa is common in many parts of the world including: Some sources suggest that "tufa" was used as the primary building material for most of the châteaux of the Loire Valley , France. This results from a mis-translation of the terms " tuffeau jaune" and "tuffeau blanc", which are porous varieties of the Late Cretaceous marine limestone known as chalk . Tufa

528-728: The Mono Basin and fund the Mono Basin extension. The 105 mi (169 km) extension diverted flows from Rush Creek , Lee Vining Creek , Walker Creek, and Parker Creek that would have flowed into Mono Lake . The construction of the Mono extension consisted of an intake at Lee Vining Creek, the Lee Vining conduit to the Grant Reservoir on Rush Creek, which would have a capacity of 48,000 acre⋅ft (59,000,000 m ),

SECTION 10

#1732791620303

576-574: The "San Fernando Syndicate" – including Fred Eaton, Mulholland, Harrison Otis (the publisher of The Los Angeles Times ), Henry Huntington (an executive of the Pacific Electric Railway ), and other wealthy individuals – were a group of investors who bought land in the San Fernando Valley allegedly based on inside knowledge that the Los Angeles aqueduct would soon irrigate it and encourage development. Although there

624-593: The 12.7 mi (20.4 km) Mono Craters Tunnel to the Owens River , and a second reservoir, later named Crowley Lake with a capacity of 183,465 acre⋅ft (226,301,000 m ) in Long Valley at the head of the Owens River Gorge. Completed in 1940, diversions began in 1941. The Mono Extension has a design capacity of 400 cu ft/s (11,000 L/s) of flow to the aqueduct. However,

672-650: The City of Los Angeles. Growth was so rapid that it appeared as if the city of Los Angeles would eventually assume the size of the entire county. William Mulholland continued adding capacity to the aqueduct, building the St. Francis Dam that would impound water creating the San Francisquito Reservoir, filed for additional water from the Colorado River, and began sending engineers and miners to clear

720-698: The First Aqueduct which was built entirely by Public Works, the Second Los Angeles Aqueduct was primarily built on contract by various private construction firms including R.A. Wattson Co., Winston Bros., and the Griffith Co. The Los Angeles Department of Water and Power managed the project and performed some finishing construction on the Mojave conduit and Jawbone & Dove Spring pipelines. The 137-mile-long (220 km) aqueduct

768-593: The Los Angeles Bureau of Water Works and Supply in 1929. The dam failure is the worst man-made flood disaster in the US in the 20th century and the second largest single-event loss of life in California history after the 1906 San Francisco earthquake . In an effort to find more water, the city of Los Angeles reached farther north. In 1930, Los Angeles voters passed a third US$ 38.8 million bond to buy land in

816-635: The Mono Basin to 10,000 acre⋅ft (12.3 million m ) per year. In 1956, the State Department of Water Resources reported that Los Angeles was exporting only 320,000 acre-feet (390 million cubic metres) of water of the 590,000 acre⋅ft (730 million m ) available in the Owens Valley and Mono Basin. Three years later, the State Water Rights Board warned Los Angeles that they could lose rights to

864-764: The South Haiwee Reservoir. The flow then continues 115 miles (185 km) south through a series of pressure pipelines and concrete conduits where it connects with the First Aqueduct at the North Portal of the Elizabeth Tunnel near the Fairmont Reservoir. The San Francisquito Tunnels (which include the Elizabeth Tunnel) have a flow capacity of 1,000 cu ft/s (28,000 L/s) and are large enough to handle

912-597: The State Water Resources Control Board (SWRCB) in 1974 increased exports to 167,000 acre⋅ft (206 million m ) per year. These export levels severely impacted the region's fish habitat, lake level, and air quality, which led to a series of lawsuits. The results of the litigation culminated with a SWRCB decision to restore fishery protection (stream) flows to specified minimums, and raise Mono Lake to 6,391 feet (1,948 m) above sea level. The agreement limited further exports from

960-990: The Terminal structure and Cascades. Water from the Terminal structure can then flow to either the Cascade or penstock to the Foothill Power Plant and into the Upper Van Norman Reservoir. In addition to the construction in the Northern and Southern sections, improvements were also made to the lined canal between the Alabama Gates and the North Haiwee Reservoir in the Northern Section that consisted of adding 24 in (610 mm) sidewalls to both sides of

1008-552: The Upper Van Norman Reservoir. The Second Aqueduct was not built as a single contiguous conduit. For design and construction purposes the aqueduct was divided into Northern and Southern sections and the two are connected by the San Francisquito Tunnels, which are part of the First Aqueduct. The Northern Section carries water starting at the North Haiwee Reservoir through the Haiwee Bypass passing around

SECTION 20

#1732791620303

1056-873: The aqueduct diverts the Owens River into an unlined canal to begin its 233 mi (375 km) journey south to the Lower San Fernando Reservoir. This reservoir was later renamed the Lower Van Norman Reservoir . The original project consisted of 24 mi (39 km) of open unlined canal, 37 mi (60 km) of lined open canal, 97 mi (156 km) of covered concrete conduit, 43 mi (69 km) of concrete tunnels, 12.00 mi (19.31 km) steel siphons, 120 mi (190 km) of railroad track, two hydroelectric plants, three cement plants, 170 mi (270 km) of power lines, 240 mi (390 km) of telephone line, 500 mi (800 km) of roads and

1104-457: The aqueduct numerous times, and opened sluice gates to divert the flow of water back into Owens Lake . The lake has never been refilled, and is now maintained with a minimum level of surface water to prevent the introduction of dangerous, toxic lake-floor dust into the local community. In 1917, The Bureau of Los Angeles Aqueduct sought to build a holding reservoir to regulate flow and provide hydroelectric power and storage in case of disruption to

1152-465: The aqueduct system. The initial site chosen was in Long Valley along the Owens River, but Eaton, who had bought up much of the valley in anticipation of the need for a reservoir, refused to sell the land at the price offered by Los Angeles. Mulholland then made the decision to move the reservoir to San Francisquito Canyon above what is now Santa Clarita, California . The resulting St. Francis Dam

1200-410: The canal and the raising of overcrossings. This work increased the capacity of the lined canal from 710 cu ft/s (20,000 L/s) to 900 cu ft/s (25,000 L/s) cfs. The increased flows provided by the second aqueduct lasted only from 1971 through 1988. In 1974 the environmental consequences of the higher exports were first being recognized in the Mono Basin and Owens Valley. This

1248-601: The city of Los Angeles if the St. Francis Dam had not collapsed. The catastrophic failure of the St. Francis Dam in 1928 killed an estimated 431 people, flooded parts of Santa Clarita, and devastated much of the Santa Clara River Valley in Ventura County . The failure of the dam raised the question in a number of people's minds whether the city had engineering competence and capability to manage such

1296-526: The dam laterally 5 feet (1.5 m). Originally, the Lower Van Norman reservoir was operated near full capacity of 1,134.6 feet (345.8 m). However, the maximum operating height was reduced to 1,125 feet (343 m) in 1966 following seismic hazard review. Fortuitously, at the time of the 1971 San Fernando earthquake the water height was 1,109 feet (338 m) (about half capacity: 3.6 billion US gallons (14 × 10 ^  m) of water) as

1344-407: The deposits creates a wet habitat ideal for these plants. Modern tufa is formed from alkaline waters, supersaturated with calcite. On emergence, waters degas CO 2 due to the lower atmospheric p CO 2 (see partial pressure ), resulting in an increase in pH. Since carbonate solubility decreases with increased pH, precipitation is induced. Supersaturation may be enhanced by factors leading to

1392-753: The flow of both aqueducts. Once the combined flow reaches the penstocks above Power Plant #2, water is diverted into the Southern Section of the second aqueduct through the Drinkwater Tunnel to the Drinkwater Reservoir. The last segment of pipe, known as the Saugus Pipeline, carries water south past Bouquet Canyon , Soledad Canyon and Placerita Canyon in the city of Santa Clarita . From there it roughly parallels Sierra Highway before it enters Magazine Canyon near

1440-523: The flow was limited to 123 cu ft/s (3,500 L/s) due to the limited downstream capacity of the Los Angeles Aqueduct. Full appropriation of the water could not be met until the second aqueduct was completed in 1970. From 1940 to 1970, water exports through the Mono Extension averaged 57,067 acre-feet (70 million cubic meters ) per year and peaked at 135,000 acre⋅ft (167 million m ) in 1974. Export licenses granted by

1488-424: The following classes of fluvial tufa: Lacustrine tufas are generally formed at the periphery of lakes and built-up phytoherms (freshwater reefs), and on stromatolites . Oncoids are also common in these environments. Although sometimes regarded as a distinct carbonate deposit, calcareous sinter formed from ambient temperature water can be considered a sub-type of tufa. Calcareous speleothems may be regarded as

Van Norman Dams - Misplaced Pages Continue

1536-700: The formation of the MWD would be limited to 27.65 square miles. The Cascades, which was completed on November 5, 1913, is located near the intersection of Foothill Boulevard and Balboa Boulevard, four miles northwest of San Fernando. It was designated as a California Historical Landmark on July 28, 1958. Notes Further reading Tufa Tufa is a variety of limestone formed when carbonate minerals precipitate out of water in unheated rivers or lakes. Geothermally heated hot springs sometimes produce similar (but less porous) carbonate deposits, which are known as travertine or thermogene travertine . Tufa

1584-1010: The heading at the San Jacinto Tunnel that he knew was key to the construction of the Colorado River Aqueduct . The aqueduct's water provided developers with the resources to quickly develop the San Fernando Valley and Los Angeles through World War II. Mulholland's role in the vision and completion of the aqueduct and the growth of Los Angeles into a large metropolis is recognized with the William Mulholland Memorial Fountain, built in 1940 at Riverside Drive and Los Feliz Boulevard in Los Feliz. Mulholland Drive and Mulholland Dam are both named after him. Many more cities and unincorporated areas would likely have annexed into

1632-469: The residents in Owens Valley, and creating a false sense of urgency around the completion of the aqueduct for Los Angeles residents. By the 1920s, the aggressive pursuit of water rights and the diversion of the Owens River precipitated the outbreak of violence known as the California water wars . Farmers in Owens Valley, following a series of unmet deadlines from LADWP, attacked infrastructure, dynamiting

1680-612: The system. The dam's collapse two years later killed at least 431 people, halted the rapid pace of annexation, and eventually led to the formation of the Metropolitan Water District of Southern California to build and operate the Colorado River Aqueduct to bring water from the Colorado River to Los Angeles County . The continued operation of the Los Angeles Aqueduct has led to public debate, legislation, and court battles over its environmental impacts on Mono Lake and other ecosystems. The aqueduct project began in 1905 when

1728-408: The voters of Los Angeles approved a US$ 1.5 million bond for the 'purchase of lands and water and the inauguration of work on the aqueduct'. On June 12, 1907, a second bond was passed with a budget of US$ 24.5 million to fund construction. Construction began in 1908 and was divided into eleven divisions. The city acquired three limestone quarries, two Tufa quarries and it constructed and operated

1776-425: The water they were permitted for but not appropriating. Faced with the possible loss of future water supply, Los Angeles began the five-year construction of the aqueduct in 1965 at a cost US$ 89 million. Once the city received diversion permits, water exports jumped in 1970, adding 110,000 AF that year into the aqueduct system. By 1974, exports climbed to 450,000 acre⋅ft (560 million m ) per year. Unlike

1824-430: The year. In 1911 and 1912, employment ranged from 2,800 to 3,800 workers. The number of laborers working on the aqueduct at its peak was 3,900. In 1913, the City of Los Angeles completed construction of the first Los Angeles Aqueduct. The aqueduct as originally constructed consisted of six storage reservoirs and 215 mi (346 km) of conduit. Beginning 3.5 mi (5.6 km) north of Blackrock ( Inyo County ),

1872-537: Was again severely damaged, but as then it was in use only as a holding basin, the consequences were minor. The near failure of the Lower Van Norman Dam brought about major changes in the way public agencies and engineers viewed seismic safety, particularly regarding embankments of fine sands and silts and numeric dynamic analysis of dams. Also, it resulted in many mandated dam safety reassessments. Los Angeles Aqueduct The aqueduct's construction

1920-467: Was completed in 1926 and created a reservoir capacity of 38,000 acre-feet (47,000,000 m ). On March 12, 1928, the dam catastrophically failed, sending a 100-foot high (30 m) wall of water down the canyon, ultimately reaching the Pacific Ocean near Ventura and Oxnard, and killing at least 431 people. The resulting investigation and trial led to the retirement of William Mulholland as the head of

1968-436: Was constructed with 42 feet (13 m) of hydraulic fill . In 1922, the dam was raised 18 feet (5.5 m) with rolled fill . The Lower Van Norman Dam was constructed with hydraulic and rolled fill. Hydraulic fill height was about 102.4 feet (31.2 m), while rolled fill was added at least five times in the dam's history, each time increasing the dam's height, totaling 39.6 feet (12.1 m) rolled fill. The last addition

Van Norman Dams - Misplaced Pages Continue

2016-528: Was controversial from the start, as water diversions to Los Angeles eliminated the Owens Valley as a viable farming community. Clauses in the city's charter originally stated that the city could not sell or provide surplus water to any area outside the city, forcing adjacent communities to annex themselves into Los Angeles. The aqueduct's infrastructure also included the completion of the St. Francis Dam in 1926 to provide storage in case of disruption to

2064-612: Was designed to flow 290 cu ft/s (8,200 L/s) and begins at the Merritt Diversion Structure at the junction of the North and South Haiwee Reservoirs, south of Owens Lake , and runs roughly parallel to the first aqueduct. Water flows entirely by gravity from an elevation of 3,760 feet (1,150 m) at the Haiwee Reservoir through two power drops to an elevation of 1,200 ft (370 m) at

2112-428: Was due largely to the aqueduct, and the city's charter which stated that the City of Los Angeles could not sell or provide surplus water to any area outside the city. Outlying areas relied on wells and creeks for water and, as they dried up, the people in those areas realized that if they were going to be able to continue irrigating their farms and provide themselves domestic water, they would have to annex themselves to

2160-502: Was followed by a series of court ordered restrictions imposed on water exports, which resulted in Los Angeles losing water. In 2005, the Los Angeles Urban Water Management Report reported that 40–50% of the aqueduct's historical supply is now devoted to ecological resources in Mono and Inyo counties. From 1909 to 1928, the city of Los Angeles grew from 61 square miles to 440 square miles. This

2208-490: Was later expanded with the construction of the Mono Extension and the Second Los Angeles Aqueduct. The aqueduct uses gravity alone to move the water and also uses the water to generate electricity, which makes it cost-efficient to operate. The construction of the Los Angeles Aqueduct effectively eliminated the Owens Valley as a viable farming community and eventually devastated the Owens Lake ecosystem. A group labeled

2256-490: Was limited by earthquake damage to the outlet lines and drainage towers. Reconstruction was proposed, but abandoned after geologic evaluation showed the inherent instability of the dams' foundations. As a replacement, the Los Angeles Dam was constructed between the original Lower and Upper Van Norman Dam structures in a more stable location. During the 1994 Northridge earthquake , the Lower Van Norman reservoir area

2304-462: Was made in 1929–30. 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 for three days. Later, it was estimated that a dam failure could have killed 123,400. The Upper Van Norman reservoir was operating at about one-third capacity at the time of the earthquake. The quake lowered dam height 3 feet (0.91 m) and displaced

#302697