The Yellowstone is not the longest “undammed river” in the United States

Though free of large impoundments such as those on the Missouri, the Yellowstone is not the longest “undammed river” in the United States, as it is often described. Diversion dams block the river at six sites between Billings and Sidney. Like 12-Mile Dam on the Tongue, the Yellowstone’s Huntley, Waco-Custer, Rancher’s Ditch, Yellowstone, Cartersville, and Intake diversion dams were built decades ago to provide water for crop irrigation.

LINK (via: Montana Outdoors)

Those diversion dams are responsible for the loss of hundreds of thousands of fish annually who move in the diversion canals along with the water. Now two giant fish screens have been installed which will help save fish on the Yellowstone.

LINK (via: The Billings Gazette)