The Tyhee Siphon is a 5,400-foot long, 78-inch inside diameter concrete pipe which conveys irrigation water between surface ditches as part of the Fort Hall Irrigation Project. Originally constructed in the early 1900s, the siphon was first rehabilitated in the 1940s by installing an interior, sectional steel liner. Over time, both the steel liner and concrete pipe had deteriorated to the point where leakage and exfiltration was causing settlement and damage to Siphon Road, located above and adjacent to the siphon. This caused the Bureau of Indian Affairs to pursue the current rehabilitation effort starting in 2009. American West Construction (AWC) was selected to complete Phase 2 of the rehabilitation project, which was completed ahead of schedule in March, 2015.