Salt Lake Co.-big Cottonwood (spencer`s)
Salt Lake Co.-big Cottonwood (spencer`s) is an earth dam located in Salt Lake County, Utah, built in 1984. It carries a High hazard potential classification and has a fair condition assessment.
About Salt Lake Co.-big Cottonwood (spencer`s)
The primary purpose of Salt Lake Co.-big Cottonwood (spencer`s) is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Salt Lake County Public Works (local government). It impounds the Big Cottonwood Creek near Holladay.
The dam stands 31 feet tall and stretches 1,420 feet across, has a maximum storage capacity of 132 acre-feet, and collects water from a drainage area of 48 square miles. Completed in 1984, the structure is 42 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 07/13/2022.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Utah dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Utah |
| County | Salt Lake |
| Nearest City | Holladay |
| River/Stream | Big Cottonwood Creek |
| Coordinates | 40.63117, -111.80442 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 31 ft |
| Dam Length | 1,420 ft |
| Year Completed | 1984 (42 years old) |
Storage & Hydraulics
| NID Storage | 132 acre-ft |
| Max Storage | 132 acre-ft |
| Normal Storage | 79 acre-ft |
| Drainage Area | 48 sq mi |
| Max Discharge | 1,030 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | SALT LAKE COUNTY PUBLIC WORKS |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 07/13/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | UT00090 |
| Federal ID | UT00090 |
| More Info | State Dam Safety Program |