Roche Harbor Lake Dam
Roche Harbor Lake Dam is an earth dam located in San Juan County, Washington, built in 2013. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Roche Harbor Lake Dam
The primary purpose of Roche Harbor Lake 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 Roche Harbor Investments Inc (private). It impounds the Tr-westcott Bay.
The dam stands 15 feet tall and stretches 315 feet across, creates a reservoir covering 28 acres, has a maximum storage capacity of 629 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 2013, the structure is relatively new.
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 07/23/2024.
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 | San Juan |
| River/Stream | Tr-westcott Bay |
| Coordinates | 48.59112, -123.12615 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 15 ft |
| Dam Length | 315 ft |
| Year Completed | 2013 (13 years old) |
Storage & Hydraulics
| NID Storage | 629 acre-ft |
| Max Storage | 629 acre-ft |
| Normal Storage | 526 acre-ft |
| Surface Area | 28 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 271 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Roche Harbor Investments Inc |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 07/23/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WA00444 |
| Federal ID | WA00444 |
| More Info | State Dam Safety Program |