Green Lake

Green Lake is an arch dam located in City and Borough of Sitka, Alaska, built in 1982. It carries a Significant hazard potential classification and has a satisfactory condition assessment.

About Green Lake

The primary purpose of Green 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 City And Borough Of Sitka (local government). It impounds the Vodopad River.

The dam stands 210 feet tall and stretches 462 feet across, creates a reservoir covering 1,120 acres, has a storage capacity of 94,000 acre-feet, and collects water from a drainage area of 28 square miles. Completed in 1982, the structure is 44 years old.

This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. 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 06/04/2025.

At 210 feet, this dam is taller than 99% of all dams in the United States.

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Significant HazardSatisfactory ConditionEmergency Action Plan: Yes

Location

StateAlaska
CountyCity and Borough of Sitka
Nearest CityNone
River/StreamVodopad River
Coordinates56.98686, -135.11362

Physical Characteristics

Dam TypeArch
NID Height210 ft
Dam Height210 ft
Dam Length462 ft
Year Completed1982 (44 years old)

Storage & Hydraulics

NID Storage94,000 acre-ft
Normal Storage94,000 acre-ft
Surface Area1,120 acres
Drainage Area28 sq mi
Max Discharge12,800 cfs
Spillway TypeUncontrolled

Ownership & Safety

PurposeHydroelectric
OwnerCity and Borough of Sitka
Owner TypeLocal Government
Hazard ClassificationSignificant
Condition AssessmentSatisfactory
Last Inspection06/04/2025
Emergency Action PlanYes

Identifiers

NID IDAK83012
Federal IDAK83012
More InfoState Dam Safety Program

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