Cogswell Dam is a rockfill dam on the West Fork of the
San Gabriel River in
Los Angeles County
Los Angeles County, officially the County of Los Angeles and sometimes abbreviated as LA County, is the most populous county in the United States, with 9,663,345 residents estimated in 2023. Its population is greater than that of 40 individua ...
,
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
. It is located 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 ...
, northeast of
Mount Wilson, and within the
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 ...
.
It forms Cogswell Reservoir, which has a capacity of .
The dam serves mainly for
flood control
Flood management or flood control are methods used to reduce or prevent the detrimental effects of flood waters. Flooding can be caused by a mix of both natural processes, such as extreme weather upstream, and human changes to waterbodies and ru ...
in conjunction with
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 ...
and
Morris Dam
Morris Dam (officially the Samuel B. Morris Dam) is a concrete gravity dam across the San Gabriel River in the U.S. state of California. It impounds Morris Reservoir, directly downstream of San Gabriel Dam.
The dam was built in the 1930s as a ...
downstream. San Gabriel Dam lies downstream.
Construction
Bonds for the dam's construction were issued in 1924. Construction began in March 1932 and was completed in April 1934, at a total cost of US$3,127,762.
[
The rock-fill dam, built by the Los Angeles County Flood Control District, is long, tall (measured from the stream bed), wide at the top, and contains of material. Its crest is above sea level and above the certified water storage elevation.][
The dam rests on crystalline granite bedrock. The buttress is thick at the base, and the height from foundation to crest is . There are concrete cutoff walls and a concrete facing slab on the dam's upstream side.][
]
See also
* 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 ...
*
*
References
Los Angeles County Department of Public Works dams
Rock-filled dams
San Gabriel River (California)
San Gabriel Mountains
Angeles National Forest
Dams completed in 1935
1935 establishments in California
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