Tesoro Water Storage Reservoir
Tesoro Water Storage Reservoir is an earth dam located in Skagit County, Washington, built in 1958. It carries a High hazard potential classification and has a fair condition assessment.
About Tesoro Water Storage Reservoir
The primary purpose of Tesoro Water Storage 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 Tesoro Refining And Marketing Co. (private). It impounds the Offstream.
The dam stands 11 feet tall and stretches 1,455 feet across, creates a reservoir covering 5 acres, has a maximum storage capacity of 47 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1958, 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 09/24/2020.
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 | Skagit |
| River/Stream | Offstream |
| Coordinates | 48.47973, -122.56052 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 11 ft |
| Dam Length | 1,455 ft |
| Year Completed | 1958 (68 years old) |
Storage & Hydraulics
| NID Storage | 47 acre-ft |
| Max Storage | 47 acre-ft |
| Normal Storage | 37 acre-ft |
| Surface Area | 5 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 163 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Tesoro Refining and Marketing Co. |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 09/24/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WA01968 |
| Federal ID | WA01968 |
| More Info | State Dam Safety Program |