Hoosier Pass is the location of the oldest known transbasin diversion project in Colorado, a ditch diverting water from a tributary of the Blue River to the Middle Fork of the South Platte River. This water was used for placer mining above Alma. By 1929, the 1.8 mile (2.9 km) East Hoosier Ditch and the 1.3 mile (2 km) West Hoosier Ditch were in operation, able to divert an aggregate 77 cubic feet per second (2.2 m3/s) of water across the continental divide.