To amend the Act of January 26, 1915, establishing Rocky Mountain National Park, to provide for the protection of certain lands in Rocky Mountain National Park and along North St. Vrain Creek and for other purposes.

Prohibits the Secretary of the Interior or any other Federal agency or officer from approving or issuing any permit for, or providing any assistance for, the construction of any new dam, reservoir, or impoundment on any segment of North St. Vrain Creek or its tributaries within the boundaries of the Rocky Mountain National Park or on the main stem of the Creek downstream to the point at which it crosses the elevation 6550 feet above mean sea level. Declares that nothing in this Act shall be construed to prevent the issuance of any permit for the construction of a new water gaging station on the Creek at the point of its confluence with Coulson Gulch.

Directs the Secretary to seek to acquire by donation or exchange certain lands within the boundaries of the Park owned by Longmont, Colorado.

Directs the Secretary of Agriculture to pursue and report to the Congress biennially on negotiations with Longmont, Colorado, concerning the city's proposed exchange of lands located in and near Coulson Gulch for Federal lands.