Gunnison Tunnel
The Gunnison Tunnel is an irrigation tunnel constructed between 1905 and 1909 by the U.S. Bureau of Reclamation in Montrose County, Colorado. The 5.8-mile-long (9.3 km) tunnel diverts water from the Gunnison River to the arid Uncompahgre Valley around Montrose, Colorado.
Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).