Spillway Dam
Spillway Dam is an earth dam located in Clackamas County, Oregon, built in 1962. It carries a High hazard potential classification and has a fair condition assessment.
About Spillway Dam
The primary purpose of Spillway Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City Of Portland Oregon (local government). It impounds the Bull Run near Troutdale, Or.
The dam stands 180 feet tall and stretches 450 feet across, creates a reservoir covering 418 acres, has a maximum storage capacity of 25,000 acre-feet, and collects water from a drainage area of 102 square miles. Completed in 1962, the structure is well into its service life at over 50 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 05/24/2022.
At 180 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 Oregon 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 | Oregon |
| County | Clackamas |
| Nearest City | Troutdale, Or |
| River/Stream | Bull Run |
| Coordinates | 45.44470, -122.15380 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 180 ft |
| Dam Height | 180 ft |
| Dam Length | 450 ft |
| Year Completed | 1962 (64 years old) |
Storage & Hydraulics
| NID Storage | 25,000 acre-ft |
| Max Storage | 25,000 acre-ft |
| Normal Storage | 21,000 acre-ft |
| Surface Area | 418 acres |
| Drainage Area | 102 sq mi |
| Max Discharge | 73,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of Portland Oregon |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 05/24/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | OR00317 |
| Federal ID | OR00317S001 |
| More Info | State Dam Safety Program |