Cogswell Dam

Cogswell Dam
Cogswell Dam
	Satellite view
	Location of Cogswell Dam in California
Country	United States
Location	San Gabriel Mountains,; Angeles National Forest,; Los Angeles County,; California
Opening date	1935
Owner(s)	Los Angeles County Department of Public Works
Dam and spillways
Type of dam	Rock-filled
Impounds	West Fork San Gabriel River
Height	266 ft (81 m)
Height (foundation)	280 ft (85 m)
Length	585 ft (178 m)
Spillway capacity	59,900 cu ft/s (1,700 m3/s)
Reservoir
Creates	Cogswell Reservoir
Total capacity	12,234 acre⋅ft (15,090,000 m3)
Catchment area	38.4 sq mi (99 km2)
Surface area	146 acres (59 ha)

Cogswell Dam is a rockfill dam on the West Fork of the San Gabriel River in Los Angeles County, California. It is in the San Gabriel Mountains, northeast of Mount Wilson, and within the Angeles National Forest.

It forms Cogswell Reservoir, which has a capacity of 8,969 acre-feet (11,063,000 m³).^[2]

It serves mainly for flood control in conjunction with San Gabriel Dam and Morris Dam downstream. San Gabriel Dam lies 13 miles (21 km) downstream.^[3]

Construction

Bonds for the dam's construction were issued in 1924. Construction began March 1932 and was completed April 1934, at a total cost of US$3,127,762.^[3]

The rock-fill dam, built by the Los Angeles County Flood Control District, is 585 feet (178 m) long, 266 feet (81 m) tall (measured from the stream bed), 18 feet (5.5 m) wide at the top, and contains 1,044,945 cubic yards (798,918 m³) of material. Its crest is 2,412 feet (735 m) above sea level and 27 feet (8.2 m) above the certified water storage elevation.^[2]

The dam rests on crystalline granite bedrock. The buttress is 750 feet (230 m) thick at the base, and the height from foundation to crest is 285 feet (87 m). There are concrete cutoff walls and a concrete facing slab on the dam's upstream side.^[3]

References

^ ^a ^b [1] ^{[dead link]}
^ ^a ^b "Dams Within the Jurisdiction of the State of California (A-G)" (PDF). California Department of Water Resources. Retrieved September 30, 2012.
^ ^a ^b ^c "Cogswell Dam" (PDF). Dpwftp.cp.la.ca.us. Retrieved November 18, 2012.

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[LACounty-1] [1] ^{[dead link]}

[DWR-2] "Dams Within the Jurisdiction of the State of California (A-G)" (PDF). California Department of Water Resources. Retrieved September 30, 2012.

[DPW-3] "Cogswell Dam" (PDF). Dpwftp.cp.la.ca.us. Retrieved November 18, 2012.

[1]

[2]

[3]

v t e Dams in Los Angeles County, California
CA Department of Water Resources	Castaic Elderberry Forebay Pyramid
LA Department of Public Works	Big Dalton Big Tujunga Cogswell Devil's Gate Eaton Wash Live Oak Morris Pacoima Puddingstone San Dimas San Gabriel Santa Anita Sawpit (disused) Sierra Madre Thompson Creek
LA Department of Water and Power	Baldwin Hills (failed) Bouquet Chatsworth (unsafe: emptied) Dry Canyon (unsafe: emptied) Encino Fairmont Los Angeles Mulholland Silver Lake St. Francis (failed) Stone Canyon Van Norman (aka San Fernando) (failed)
US Army Corps of Engineers	Hansen Santa Fe Sepulveda Whittier Narrows
Other	Brown Mountain Dam (disused) Las Virgenes Little Rock Rindge (disused)

Construction

See also

References