Stone Canyon Reservoir and Upper Stone Canyon Reservoir are adjoining reservoirs in the Westside region of

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. Situated in the

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above sea level Height above mean sea level is a measure of the vertical distance (height, elevation or altitude) of a location in reference to a historic mean sea level taken as a vertical datum. In geodesy, it is formalized as ''orthometric heights''. The comb ...

, the reservoirs lie in the Bel Air neighborhood, south of

Mulholland Drive Mulholland Drive is a street and road in the eastern Santa Monica Mountains of Southern California. It is named after pioneering Los Angeles civil engineer William Mulholland. The western rural portion in Los Angeles and Ventura Counties is nam ...

and west of North Beverly Glen Boulevard. The main reservoir is the Stone Canyon Reservoir with the much smaller, cone-shaped Upper Stone Canyon Reservoir adjoining it to the north. The two reservoirs supply the Westside water subsystem, including service to around 400,000 people in Pacific Palisades, the

, and

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History

The reservoirs are owned by the

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. The main reservoir, which is the lower reservoir and the larger of the two, is situated south of the upper reservoir. It was designed and built in 1924 by the

's water branch, the Bureau of Water Works and Supply (BWWS).23rd Annual Report of the Board of Public Service Commissioners, Report of the Chief Engineer As with most other BWWS reservoirs of the time, it is of earth fill construction which was placed utilizing the

hydraulic sluicing Hydraulic fill is a means of selectively emplacing soil or other materials using a stream of water. It is also a term used to describe the materials thus emplaced. Gravity, coupled with velocity control, is used to effect the selected depositi ...

method. This method was pioneered and refined by

William Mulholland William Mulholland (September 11, 1855 – July 22, 1935) was an Irish Americans, Irish American self-taught civil engineer who was responsible for building the infrastructure to provide a water supply that allowed Los Angeles to grow into the la ...

. This reservoir had an original capacity of . In the mid 1950s, the upstream part of the dam was rebuilt as a roller compacted backfill founded on rock, while the downstream part remained unchanged. The rehabilitation work was completed in 1956. The high dam was examined from the safety considerations to withstand seismic factors. Seismic studies were carried out in 2002 and the conclusion was that the Lower Stone Canyon Dam could be "operated safely with the reservoir level at its design elevation of ."

Project features

Stone Canyon Reservoir is composed of two reservoirs, namely, the larger Lower at and the Upper at . The elevation of the Lower is at full reservoir level and at maximum water level. When built, both reservoirs stored treated drinking water. This enabled surface runoff to flow into the reservoir. resulting in contamination. The Lower Reservoir is in an irregular shape with a shore line of and surface area of . The 70 ton water treatment plant commissioned in January 1952 is located downstream. The intake was designed as an inclined tower to maximize the natural site conditions which enabled the design of the tower to be based on the unit weight factor. It was established in 1952 for a total of around $9 million. Construction was partly funded by the

California Department of Transportation Environmental Enhancement California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the mo ...

and Mitigation Grant Program. Taking advantage of the natural terrain, an inclined tower was built that eliminated the need for an access bridge and reduced the unit bearing load. A somewhat unusual change in

radon Radon is a chemical element with the symbol Rn and atomic number 86. It is a radioactive, colourless, odourless, tasteless noble gas. It occurs naturally in minute quantities as an intermediate step in the normal radioactive decay chains through ...

level began at the canyon in 1984, possibly a result of a reservoir level change. At least part of the lower reservoir expansion included

asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term a ...

linings. Some of the landslides at the upper reservoir were caused by undercut grading. To compact the area brush and reduce the height of the flammable materials, heavy drums were filled with water and then rolled up and down the slopes. Proposed 2004 system changes included removing the reservoir from normal operating service, and retaining it for emergency storage only. However, as the reservoirs were of open surface type, in later years, they did not conform to the prescribed water quality standards for potable water. The Federal and State Surface Water Treatment Rules prescribed that covering of all smaller reservoirs and building of filtration plants at all large ones was essential. The authorities connected with the Lower Stone Reservoir were directed by the Department to build a filtration plant facility below the dam, in a area within of Stone Canyon Road residences. In the studies conducted in 1991 on the quality of the water stored in the two surface reservoirs it was concluded that the water stored had high turbidity values (about 1 NTU which was more than the standard acceptable value of 0.5 NTU) as it received surface water inflows from the catchment of the reservoir. It was also noted that the

coliform Coliform bacteria are defined as either motile or non-motile Gram-negative non- spore forming Bacilli that possess β-galactosidase to produce acids and gases under their optimal growth temperature of 35-37°C. They can be aerobes or facultativ ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

level was also higher than the upper reservoir. High algae count was also reported during the summer season. Further, the average THM value measured was a high of 24 µg/L. These aspects of deteriorating water quality of the two surface reservoirs necessitated provision of water treatment plant (filtration plant). However, following the Federal and State Government directives, a membrane filtration and pumping facility was built at an estimated cost of $65 to 70 million to supply of water per day to serve 400,000 customers. A security fence was also built around the facility.

Decommissioning of Lower Stone Canyon Reservoir

Planning for further improvement in treatment and supply facility was undertaken in 2004. This was to ensure removal of potential contaminants from the Lower Stone Canyon Reservoir water. This was proposed to conform to the safe drinking water standards through a microfiltration plant that would treat the surface water through membrane filtration along with chemical disinfection before it entered the distribution system. This new plant also provided for fully automated remote operation. This plant was located in a valley on the left abutment of Lower Stone Canyon Dam near the existing reservoir outlet. All visible elements were Architectural aesthetics ensured adoption of existing trees with its precincts and acoustics of operation ensuring an

ambient noise level In atmospheric sounding and noise pollution, ambient noise level (sometimes called background noise level, reference sound level, or room noise level) is the background sound pressure level at a given location, normally specified as a reference l ...

of not more than 30 decibels. The project titled “

The Stone Canyon Water Quality Improvement Project ''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the m ...

” was undertaken by the

with allocation of $75 million. The project construction was started in 2004 and completed by the end of 2007. Along with this project, the Los Angeles Department of Water and Power also undertook an upgrade of the security and safety of the city's water system at a cost of $132 million spent over a five-year period. This security initiative was an outcome of the terrorist attacks of 9/11. After the upgrade of the water treatment and supply facility, the Lower Stone Reservoir is not in use except in emergency situations. The unique feature of this project is that a 63 inches diameter bypass HDPE pipeline is laid over a length of . Half of this length is submerged below the surface of the lower reservoir bypassing it from where the treated water is directly supplied to the customers from the

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. The lower reservoir has a capacity of of water while the upper reservoir has capacity to store of water. However, the upper reservoir has been built with sufficient safeguards against

surface runoff Surface runoff (also known as overland flow) is the flow of water occurring on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when th ...

by way of boundary channels which is not the case in the lower reservoir. Moreover, the Lower Stone Canyon reservoir no longer supplies customers directly. The reservoirs are subject to flash floods, when they are put out of service during the period of the flood. In case of 100 year storm rainfall, the Upper Stone Canyon Reservoir spills to the lower reservoir where it is taken through the filtration process before supplying to the customers.

Decommissioning of the Upper Stone Canyon Reservoir

A proposal to replace the existing Upper Stone Canyon Reservoir is under active consideration. The proposal is to replace the surface reservoir with three underground reservoirs beneath it to store of water. The underground structures are proposed to be covered initially with soil and then covered over with local vegetation. Hiking trails are also proposed to pass through the filled up area as a recreational activity to trek the canyon. The objective of this project is basically to follow the regulations set under the Federal Laws for uncovered reservoirs. The lower reservoir has already been decommissioned for regular use but with provision to address emergency situations with a small water treatment plant built to handle such a situation. In case of fire emergency it is planned that the lower reservoir which has enough storage could provide firefighting requirements. The security aspect is also suitable addressed with the project of transferring water under the Stone Canyon Water Quality Improvement Project. Last reported in 2009, the Environment Impact assessment study of this project was under way with the Board of Water and Power Commissioners entailed to take a decision regarding the proposed project.

In fiction

The reservoir has been used as a setting in movies and novels. In 1974, the reservoir was used as a location for the movie ''

Chinatown A Chinatown () is an ethnic enclave of Chinese people located outside Greater China, most often in an urban setting. Areas known as "Chinatown" exist throughout the world, including Europe, North America, South America, Asia, Africa and Austra ...

''. Page one of the first galley proofs of

Irving Wallace Irving Wallace (March 19, 1916 – June 29, 1990) was an American best-selling author and screenwriter. He was known for his heavily researched novels, many with a sexual theme. Early life Wallace was born in Chicago, Illinois, to Bessie Liss a ...

1974 Major events in 1974 include the aftermath of the 1973 oil crisis and the resignation of United States President Richard Nixon following the Watergate scandal. In the Middle East, the aftermath of the 1973 Yom Kippur War determined politics; f ...

novel ''

The Fan Club ''The Fan Club'' is a novel by Irving Wallace published in 1974 about a group of young men who stalk and plan to kidnap and coerce a popular actress into having sex with them. Plot summary Adam Malone is a supermarket manager in Los Angeles ...

'' is set overlooking Stone Canyon Reservoir. Page two of '' Sunset Express'', a

1996 File:1996 Events Collage.png, From left, clockwise: A Centennial Olympic Park bombing, bomb explodes at Centennial Olympic Park in Atlanta, set off by a radical Anti-abortion violence, anti-abortionist; The center fuel tank explodes on TWA Flight 8 ...

detective novel Detective fiction is a subgenre of crime fiction and mystery fiction in which an investigator or a detective—whether professional, amateur or retired—investigates a crime, often murder. The detective genre began around the same time as s ...

Robert Crais Robert Crais (pronounced ) (born June 20, 1953) is an American author of detective fiction. Crais began his career writing scripts for television shows such as ''Hill Street Blues'', ''Cagney & Lacey'', '' Quincy'', ''Miami Vice'' and ''L.A. Law ...

, is set by the reservoir.

Overlook

The 55-mile-long Mulholland Scenic Parkway and Corridor is one of the most famous thoroughfares in the US and includes the of

, which passes through the City of Los Angeles. This drive was constructed in 1924 with the objective of providing a scenic panorama of the mountains, beaches and reservoirs along its winding route. In 1994, the Stone Canyon Reservoir Overlook was developed on the south side of Mulholland Drive. Funds for this facility were provided by the California Department of Transportation Environmental Enhancement and Mitigation Grant Program.

Recreation

Stone Canyon Reservoir is closed to the public. There is no fishing, sailing, or swimming.

Notable residents

The 1959 Henry Singleton house, the 1972

Wilt Chamberlain Wilton Norman Chamberlain (; August 21, 1936 – October 12, 1999) was an American professional basketball player who played as a Center (basketball), center. Standing at tall, he played in the National Basketball Association (NBA) for 14 yea ...

house, and

Della Reese Delloreese Patricia Early (July 6, 1931 – November 19, 2017), known professionally as Della Reese, was an American jazz and gospel singer, actress, and ordained minister whose career spanned seven decades. She began her long career as a s ...

's house overlook the reservoir.

References

{{authority control Reservoirs in Los Angeles County, California Bel Air, Los Angeles Beverly Crest, Los Angeles Infrastructure completed in 1952 1952 establishments in California Reservoirs in California Reservoirs in Southern California