Lake Dorothy Hydroelectric
The Lake Dorothy Hydroelectric Project is being developed by Alaska Electric Light and Power (AEL&P) to meet Juneau, Alaska’s growing need for electricity. The project will add a level of reliability to the existing system and will help reduce the need for supplemental diesel generation. Situated on the east bank of the Taku Inlet, the project is located approximately 17 air miles southeast of Juneau, and is being developed in two phases. The first phase has been completed and consists of a 900-ft intake tunnel, a lake tap into Lake Dorothy at a depth of approximately 140 ft below the water surface, a diversion dam and intake structure at Bart Lake, a 2.5 mi access road to Bart Lake, a steel penstock along the alignment, and a powerhouse and switchyard bench blasted into solid rock.
Lachel was selected by AEL&P to provide siting, geotechnical and civil engineering, tunnel and powerhouse excavation design, constructability reviews, and cost estimating services for Phase 1 of the project. During construction, Lachel provided construction management and oversight including resident engineering and tunnel inspection services. In addition, Lachel assisted AEL&P with geologic mapping, and rock quality and rock support evaluation and documentation.
Phase 2 of the project will consist of an additional 18,000 ft of 10-ft-diameter water tunnel, a 2,000-ft vertical shaft, and additional turbines at the powerhouse to further utilize the water and head from Lake Dorothy.