22 Oct 2018 The National Rivers and Streams Assessment (NRSA) is a collaborative survey that provides information on the ecological condition of the 17 Oct 2018 National Rivers & Streams Assessment 2018-19 Field Operations NRSA 2018-19 Field Operations Manual NonWadeable (PDF)(159 pp, National Rivers and Streams Assessment Final Manual Field Operations Manual Additional precautions to prevent transfer of Whirling Disease spores, New databases, the Wadeable Stream Assessment (WSA) and the National River and Arizona/New Mexico Mountains 37 ?1.3 ?1.3 1.41 1.48 ?1.3 2.35 2.16 of the NRSA: Field Operations Manual (USEPA, 2007; EPA-841-B-07-009).1 May 2013 National Rivers and Streams Assessment: Field Operations Manual Other Rivers- new 5 and above order sites that are not considered