When is a river or river segment evaluated for eligibility for possible inclusion in the National Wild & Scenic Rivers System?

There are three instances when federal agencies assess eligibility: 1) at the request of Congress through specific authorized studies; 2) through their respective agency inventory and planning processes; or 3) during National Park Service evaluation of a Section 2(a)(ii) application by a state. River areas identified through the inventory phase are evaluated for their free-flowing condition and must possess at least one outstandingly remarkable value.