Rock Island
Rock Island is a gravity dam located in Douglas County, Washington, built in 1932. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Rock Island
The primary purpose of Rock Island 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 Chelan County, Wa (public utility). It impounds the Columbia River near Vantage, Wa.
The dam stands 71 feet tall and stretches 3,108 feet across, creates a reservoir covering 3,120 acres, has a maximum storage capacity of 131,000 acre-feet, and collects water from a drainage area of 89,400 square miles. Completed in 1932, the structure is well-established, with more than 75 years of service.
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 06/15/2022.
At 71 feet, this dam is taller than 96% 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 | Douglas |
| Nearest City | Vantage, Wa |
| River/Stream | Columbia River |
| Coordinates | 47.34236, -120.09432 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 71 ft |
| Dam Height | 71 ft |
| Dam Length | 3,108 ft |
| Year Completed | 1932 (94 years old) |
Storage & Hydraulics
| NID Storage | 131,000 acre-ft |
| Max Storage | 131,000 acre-ft |
| Normal Storage | 113,700 acre-ft |
| Surface Area | 3,120 acres |
| Drainage Area | 89,400 sq mi |
| Max Discharge | 920,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | PUD #1 of Chelan County, WA |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/15/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WA00084 |
| Federal ID | WA00084 |
| More Info | State Dam Safety Program |