Project Description

The Lake Dorothy Hydroelectric Project is being developed by the oldest utility company in the State of Alaska at a site located 17 air miles southeast of Juneau, Alaska. When power generation begins in 2002, the Lake Dorothy Hydroelectric Project will be the highest head hydro project in North America. With a lake elevation of 2440 ft and a powerhouse located at sea level, the project will generate 34.4 MW of electrical power to provide for the growing residential, business and industrial needs of Alaska's capital city and its environs.

Scope of Services

Beginning in 1995, LACHEL & Associates, Inc. (LFA) was selected to provide the general civil engineering, siting, geotechnical investigations, underground design, constructibility, and detailed cost estimates of the project from inception through completion. Included in the project features are more than 15,000 ft of 12-ft-diameter tunnel from the lake to the powerhouse, an underground penstock to resist the very high heads, and a powerhouse and switchyard bench blasted into solid rock. A unique feature of the project will be an underwater lake tap into the bottom of the lake beneath 240 ft of water. Ironically, this deepest of North American lake taps will be provided to the company which used the world's first underwater lake tap to access the Annex Creek lake in 1911. The development of this modern keynote project will contribute significantly to the environmentally clean development of the Juneau-Douglas area.

Client

Alaska Electric Light & Power Company