US HB4870

Designates approximately 98.5 miles of Montana streams in the Greater Yellowstone Ecosystem as Wild and Scenic Rivers, including the Madison River (42 miles), Gallatin River (39.5 miles), Hyalite Creek (4.6 miles), Cabin Creek (7.3 miles), and Middle Fork of Cabin Creek (5.1 miles)

Secretary of Agriculture would administer the Madison and Gallatin Rivers as recreational rivers and the three creek segments as scenic rivers

Protects existing water rights including Federal, Tribal, and interstate water compacts, as well as Montana state water rights

Preserves current operations of Hebgen Dam and Madison Dam (FERC P-2188), explicitly allowing continued licensing, relicensing, and potential hydropower expansion at Hebgen Dam while prohibiting dam expansion into designated river segments

Requires landowner consent for any federal land acquisition within designated boundaries and authorizes appropriations as necessary for implementation