Doyon Management Services and American West Construction will be working with the Bureau of Indian Affairs to rehabilitate 3,000 LF of the Tyhee Siphon, which is a 5,500 LF, seventy-two inch diameter underground pipe, with an entry and exit structure that delivers irrigation water to 11,000 acres of farmland. The siphon was originally constructed in the early 1900’s and was modified in the 1940’s by installing a one-quarter inch thick steel liner inside the pipe.  Over time, this liner and the concrete pipe have deteriorated to the point that significant leaks are a common event. This project is the last phase of the three-phase project which includes removing and replacing the existing liner, entirely replacing sections of the existing siphon, rehabilitating the siphon outlet, and replacing the trash rake and trash rack system at the inlet of the siphon.