Lake Forest Park Reservoir
Lake Forest Park Reservoir is an earth dam located in King County, Washington, built in 1962. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Lake Forest Park Reservoir
The primary purpose of Lake Forest Park Reservoir 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 Seattle Public Utilities (local government). It impounds the Tr-lyon Creek-offstream near Lake Forest Park.
The dam stands 30 feet tall and stretches 2,320 feet across, creates a reservoir covering 8 acres, and has a maximum storage capacity of 206 acre-feet. 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 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 09/30/2020.
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 | King |
| Nearest City | Lake Forest Park |
| River/Stream | Tr-lyon Creek-offstream |
| Coordinates | 47.77034, -122.27861 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Length | 2,320 ft |
| Year Completed | 1962 (64 years old) |
Storage & Hydraulics
| NID Storage | 206 acre-ft |
| Max Storage | 206 acre-ft |
| Normal Storage | 184 acre-ft |
| Surface Area | 8 acres |
| Max Discharge | 10 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Seattle Public Utilities |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/30/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WA00217 |
| Federal ID | WA00217 |
| More Info | State Dam Safety Program |