Site Engineer Alyeska Pipeline Service Company, Alaska, United States
Abstract Submission: The Salmon Creek Dam located near Juneau, Alaska gained recognition as a National Historic Civil Engineering Landmark in March 2020 and was formally dedicated as such in September 2022. Its major significance is its geometry. It was the world's first fully realized constant-angle or variable-radius dam, and served as the prototype for many such dams constructed in deep vee-shaped canyons in the early and middle 20th Century. The dam was completed in August 1914, within days of the breakout of World War I, and remains an important source of water and power in Juneau today.
The constant angle dam concept, rooted in the basic hoop-stress equation but counterintuitive in application, served to reduce concrete quantities by 33% over more conventional gravity dam concepts at Salmon Creek, and enabled placement in a constrained bedrock ridge formation at the canyon base. The resulting economy was critical to implementation and to the financial success of its developer, the Alaska Gastineau Mine Company (which built it primarily for hydroelectric power generation).
This presentation will describe the planning and construction of the dam, the technical basis and durable influence of the constant angle concept, and the historical figures who made it happen. It will also recognize the history and heritage contributions of the late Scott Willis, P.E. of Alaska Light and Power, whose research and writings formed the basis for the Historic Civil Engineering Landmark application.
