Cogswell Reservoir is a man-made reservoir located in the San Gabriel Mountains of Los Angeles County, California.
Wind
Humidity
The reservoir was built in 1954 by the Los Angeles County Department of Public Works as part of the San Gabriel River Watershed. It is a significant source of drinking water for the region and can store up to 8,000 acre-feet of water.
Cogswell Reservoir is fed by both surface flow and snowpack from the San Gabriel Mountains. The San Gabriel River, which originates from the mountains, is the primary surface flow provider to the reservoir. Snowmelt from the surrounding mountains also contributes to the reservoir's water supply.
The water from Cogswell Reservoir is used for both agricultural and recreational purposes. The water is mainly used for irrigation in the San Gabriel Valley, while recreational activities such as fishing, boating, and hiking are also popular in the area. The reservoir is managed by the Los Angeles County Department of Public Works and is an important source of water for the region.
| Storage 24hr Change | 0.0% |
| Percent of Normal | 243% |
| Minimum |
15.0 acre-ft
2021-09-06 |
| Maximum |
8,892.0 acre-ft
2023-01-18 |
| Average | 448 acre-ft |
| Dam_Height | 266 |
| Hydraulic_Height | 239 |
| Drainage_Area | 38.4 |
| Year_Completed | 1935 |
| Nid_Storage | 8969 |
| Hazard_Potential | High |
| Primary_Dam_Type | Rockfill |
| River_Or_Stream | Wfk San Gabriel R |
| Surface_Area | 146 |
| Dam_Length | 585 |
| Nid_Height | 266 |
| Location | Reservations | Toilets |
|---|---|---|
Glenn Camp
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Glenn Camp Campground (Hike or bike in 7 miles)
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Spring Camp Campground
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Spring Camp
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Devore
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Devils Cyn
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Gaging Station Below Spillway Of Cogswell Dam (Ne 1/4, Se 1/4, Sec 19, T2N, R10W) To Confluence With Nf San Gabriel River (Sw 1/4.Sw 1/4, Sec 15, T2N, R9W)
Cooper Canyon- Near State Highway 2 (Sw 1/4, Ne 1/4, Sec 16, T3N, R10W To Confluence With Little Rock Creek
North Fork - Confluence Of Soldier And Coldbrook Creeks (Se1/4,Sw1/4, Sec) 5, T2N,,R9W To Conflluence With West Fork Of San Gabriel (Sw 1/4,Sw1/4, Sec 17, T2N, R8W)
West Fork - Headwaters (Se 1/4, Ne 1/4, Sec 14, T2N, R12W) To Cogswell Reservoir (Ne 1/4, Sw 1/4, Sec 24, T2N, R9W
Mainstream - Confluence With Cooper Canyon To Confluence Wit South Fork Little Rock Creek
Mainstream - Headwaters To Confluence With Cooper Canyon