Spencer Lake is a rockfill dam located in San Juan County, Washington, built in 1983. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 42 ft42 ft tall and 120 ft long, taller than 88% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic rockfill embankment section and the water level is illustrative.
About Spencer Lake
The primary purpose of Spencer Lake 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 Seattle Pacific University (private). It impounds the Unnamed Stream, Thatcher Bay near N/a.
The dam stands 42 feet tall and stretches 120 feet across, creates a reservoir covering 74 acres, has a maximum storage capacity of 3,117 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1983, the structure is 43 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 07/19/2017.
At 42 feet, this dam is taller than 88% of dams nationwide.
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Location
| State | Washington |
| County | San Juan |
| Nearest City | N/a |
| River/Stream | Unnamed Stream, Thatcher Bay |
| Coordinates | 48.55397, -122.81278 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 42 ft |
| Dam Height | 42 ft |
| Dam Length | 120 ft |
| Year Completed | 1983 (43 years old) |
Storage & Hydraulics
| NID Storage | 3,117 acre-ft |
| Max Storage | 3,117 acre-ft |
| Normal Storage | 3,038 acre-ft |
| Surface Area | 74 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 200 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | Seattle Pacific University |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 07/19/2017 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | WA00494 |
| Federal ID | WA00494 |
| More Info | State Dam Safety Program |