Long Lake Dam

Long Lake Dam is a concrete dam located in City and Borough of Juneau, Alaska, built in 1973. It carries a Low hazard potential classification and has a fair condition assessment.

About Long Lake Dam

The primary purpose of Long Lake Dam 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 Alaska Industrial Development And Export Authority (public utility). It impounds the Long River near Juneau.

The dam stands 30 feet tall and stretches 337 feet across, creates a reservoir covering 1,375 acres, has a maximum storage capacity of 147,000 acre-feet, and collects water from a drainage area of 32 square miles. Completed in 1973, the structure is well into its service life at over 50 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 08/28/2019.

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Low HazardFair ConditionEmergency Action Plan: Not Required

Location

StateAlaska
CountyCity and Borough of Juneau
Nearest CityJuneau
River/StreamLong River
Coordinates58.16667, -133.73330

Physical Characteristics

Dam TypeConcrete
NID Height30 ft
Dam Length337 ft
Year Completed1973 (53 years old)

Storage & Hydraulics

NID Storage147,000 acre-ft
Max Storage147,000 acre-ft
Normal Storage147,000 acre-ft
Surface Area1,375 acres
Drainage Area32 sq mi
Max Discharge28,000 cfs
Spillway TypeUncontrolled

Ownership & Safety

PurposeHydroelectric
OwnerALASKA INDUSTRIAL DEVELOPMENT AND EXPORT AUTHORITY
Owner TypePublic Utility
Hazard ClassificationLow
Condition AssessmentFair
Last Inspection08/28/2019
Emergency Action PlanNot Required

Identifiers

NID IDAK00044
Federal IDAK00044
More InfoState Dam Safety Program

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