Pacoima Dam is a concrete
arch dam
An arch dam is a concrete dam that is curved upstream in plan. The arch dam is designed so that the force of the water against it, known as hydrostatic pressure, presses against the arch, causing the arch to straighten slightly and strengtheni ...
on
Pacoima Creek in the
San Gabriel Mountains
The San Gabriel Mountains () are a mountain range located in Los Angeles and San Bernardino counties, California, United States. The mountain range is part of the Transverse Ranges and lies between the Los Angeles Basin and the Mojave Desert ...
, in
Los Angeles County, California
Los Angeles County, officially the County of Los Angeles and sometimes abbreviated as LA County, is the List of United States counties and county equivalents, most populous county in the United States, with 9,663,345 residents estimated in 202 ...
. The reservoir it creates, Pacoima Reservoir, has a capacity of
Built by the Los Angeles County Flood Control District, which became part of the Department of Public Works, it was completed in 1928. At the time, the 371 foot (113m) high dam was the tallest arch dam in the U.S.
The dam is situated approximately northeast of
Sylmar
Sylmar is a suburban neighborhood in the San Fernando Valley and the northernmost neighborhood within the city of Los Angeles, California, United States. Historically known for its profusion of sylvan olive orchards, Sylmar can trace its past t ...
, above the
San Fernando Valley
The San Fernando Valley, known locally as the Valley, is an urbanized valley in Los Angeles County, Los Angeles County, California. Situated to the north of the Los Angeles Basin, it comprises a large portion of Los Angeles, the Municipal corpo ...
.
As a flood control structure, district routinely compensates for hydraulic deficiencies in downstream areas by restraining flows of stormwater released from the dam.
Instrumentation
As construction of Pacoima Dam began, the County of Los Angeles hired Roy W. Carlson as their concrete and soil testing engineer. He developed the world's first strain meter which could be embedded in concrete. He also developed an adiabatic calorimeter and electrical-resistance thermometers to find why the temperature of concrete increased during curing and how best to avoid cracking caused by these stresses.
Earthquake monitoring
The Pacoima Dam withstood, but was damaged by the very strong (>1 ''g'') ground movement which occurred during both the
1971 San Fernando and
1994 Northridge earthquakes. Because of concerns about the stability of the dam and especially its response to potential future earthquakes, the County of Los Angeles, with the technical support of the USGS, began monitoring the dam using continuous GPS.
See also
*
Angeles National Forest
The Angeles National Forest (ANF) of the United States Forest Service is located in the San Gabriel Mountains and Sierra Pelona Mountains, primarily within Los Angeles County in Southern California. The ANF manages a majority of the San Gabri ...
*
List of dams and reservoirs in California
Following is a list of dams and reservoirs in California in a sortable table. There are over 1,400 named dams and 1,300 named reservoirs in the state of California.
Dams in service
:''Please add to this list from the below sources.''
Former ...
*
List of lakes in California
There are more than 3,000 named lakes, reservoirs, and dry lakes in the U.S. state of California.
Largest lakes
In terms of area covered, the largest lake in California is the Salton Sea, a lake formed in 1905 which is now saline. It occup ...
References
External links
Image of workers at the bottom of a canyon at the Pacoima Dam site working on wood framing and concrete pouring, 1926.Los Angeles Times
The ''Los Angeles Times'' is an American Newspaper#Daily, daily newspaper that began publishing in Los Angeles, California, in 1881. Based in the Greater Los Angeles city of El Segundo, California, El Segundo since 2018, it is the List of new ...
Photographic Archive (Collection 1429). UCLA Library Special Collections,
Charles E. Young Research Library
The Charles E. Young Research Library is one of the largest libraries on the campus of the University of California, Los Angeles in Westwood, Los Angeles, California. It initially opened in 1964, and a second phase of construction was completed ...
,
University of California, Los Angeles
The University of California, Los Angeles (UCLA) is a public university, public Land-grant university, land-grant research university in Los Angeles, California, United States. Its academic roots were established in 1881 as a normal school the ...
.
Los Angeles County Department of Public Works dams
Arch dams
San Gabriel Mountains
San Fernando Valley
Dams completed in 1929
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