Spencer Lake

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.

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 89% of dams nationwide.

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Low HazardSatisfactory ConditionEmergency Action Plan: Not Required

Location

StateWashington
CountySan Juan
Nearest CityN/a
River/StreamUnnamed Stream, Thatcher Bay
Coordinates48.55397, -122.81278

Physical Characteristics

Dam TypeRockfill
NID Height42 ft
Dam Height42 ft
Dam Length120 ft
Year Completed1983 (43 years old)

Storage & Hydraulics

NID Storage3,117 acre-ft
Max Storage3,117 acre-ft
Normal Storage3,038 acre-ft
Surface Area74 acres
Drainage Area2 sq mi
Max Discharge200 cfs
Spillway TypeControlled

Ownership & Safety

PurposeHydroelectric
OwnerSeattle Pacific University
Owner TypePrivate
Hazard ClassificationLow
Condition AssessmentSatisfactory
Last Inspection07/19/2017
Emergency Action PlanNot Required

Identifiers

NID IDWA00494
Federal IDWA00494
More InfoState Dam Safety Program

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