Shoshone Falls Hydroelectric Project, Tunnel and Penstock, North Bank of Snake River, at West end of Intake, Tipperary Corner, Jerome County, ID

Significance: The concrete-lined tunnel was among the first, if not the first, permanent components of the Shoshone Falls Project. Begun in 1901, it took more than three years and several changes of ownership before the tunnel was complete. The current penstock, installed in 1921 to replace the original penstock, is an original component of the 1920s expansion of the Project. The larger penstock with three diversion tubes was necessary in order to feed the additional generator installed in the 1921 powerhouse as part of the Project's expansion. The tunnel and penstock are the primary features that make power generation possible as they are the sole features that could be constructed to take advantage of the 212-foot drop from the top of Shoshone Falls to the bottom in an area of extreme topographic constraints.
Survey number: HAER ID-45-C
Building/structure dates: after. 1900- before. 1922 Initial Construction