Annex Creek Reservoir Report
Nearby: Bart Lake Dam Salmon Creek
Last Updated: December 18, 2025
Annex Creek, located in Juneau, Alaska, is a private hydroelectric facility with a primary purpose of generating hydroelectric power.
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Summary
Built in 1968, this structure stands at a height of 20 feet and has a storage capacity of 23,400 acre-feet. The dam's design, a buttress core type on a rock foundation, spans 115 feet in length and covers a surface area of 264 acres.
Despite being regulated by the Federal Energy Regulatory Commission, Annex Creek poses a low hazard potential and has a moderate risk assessment rating. With a maximum discharge capacity of 458 cubic feet per second, this facility also serves recreational purposes in addition to its primary function of producing clean energy. Although its condition assessment is not available, Annex Creek is a vital component of Alaska's water resource infrastructure, demonstrating the intersection of water management and climate resilience in the region.
Year Completed |
1968 |
Dam Length |
115 |
Dam Height |
20 |
River Or Stream |
Annex Creek, Taku Inlet |
Primary Dam Type |
Other |
Surface Area |
264 |
Hydraulic Height |
20 |
Drainage Area |
6 |
Nid Storage |
23400 |
Structural Height |
20 |
Hazard Potential |
Low |
Foundations |
Rock |
Nid Height |
20 |
Seasonal Comparison
Weather Forecast
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Annex Creek