In order to be listed on the NRI, a river must be free-flowing and possess one or more Outstandingly Remarkable Values (ORVs). Thus, the eligibility analysis consists of an examination of the river's hydrology, including any man-made alterations, and an inventory of its natural, cultural, and recreational resources. There are a variety of methods to determine whether certain resources are so unique, rare or exemplary as to make them outstandingly remarkable. The determination that a river area contains ORVs is a professional judgment on the part of the interdisciplinary study team (IDT), based on objective, scientific analysis. Input from organizations and individuals familiar with specific river resources should be sought and documented as part of the process.
