Culmback is a rockfill dam located in Snohomish County, Washington, built in 1983. It carries a High hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 262 ft262 ft tall and 640 ft long, taller than 99% of U.S. dams with a recorded height. Height is drawn to scale against the Statue of Liberty, 305 ft ground to torch; the profile is a generic rockfill embankment section and the water level is illustrative.
About Culmback
The primary purpose of Culmback is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by PUD #1 of Snohomish County, Wa (public utility). It impounds the Sultan River, Skykomish River near Sultan, Wa.
The dam stands 262 feet tall and stretches 640 feet across, creates a reservoir covering 1,870 acres, has a maximum storage capacity of 193,440 acre-feet, and collects water from a drainage area of 68 square miles. Completed in 1983, the structure is 43 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 05/14/2021.
At 262 feet, this dam is taller than 99% of all dams in the United States.
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 Washington 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 | Washington |
| County | Snohomish |
| Nearest City | Sultan, Wa |
| River/Stream | Sultan River, Skykomish River |
| Coordinates | 47.97492, -121.68600 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 262 ft |
| Dam Height | 262 ft |
| Dam Length | 640 ft |
| Year Completed | 1983 (43 years old) |
Storage & Hydraulics
| NID Storage | 193,440 acre-ft |
| Max Storage | 193,440 acre-ft |
| Normal Storage | 153,260 acre-ft |
| Surface Area | 1,870 acres |
| Drainage Area | 68 sq mi |
| Max Discharge | 57,132 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | PUD #1 of Snohomish County, Wa |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/14/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WA00208 |
| Federal ID | WA00208 |
| More Info | State Dam Safety Program |