Gulkana River: Originally, the crossing was designed to be buried beneath the river in a mechanically refrigerated ditch, required by the ice-rich permafrost soils in the area., 1976-05, PCA0002-1b-10, Folder: PCA0002-1b. Alyeska Pipeline Service Company : Trans-Alaska Pipeline Construction Collection, 1976-1977, PCA 2. Alaska State Library - Historical Collections Finding Aids. https://alaska.libraryhost.com/repositories/2/archival_objects/17348 Accessed February 22, 2025.