Document: NRC Regulatory Guide
Document ID: e5306f4f-dc8c-4f60-a71c-af7ad4080384
Document Type: regulatory_guide
Title: Aquatic Environmental Studies for Nuclear Power Stations + HISTORY - HISTORY 12/2014 – DG-4023 -Proposed New Guide
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML1318/ML13186A085.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.24
CFR Part: 
CFR Title: 

Content:
es, databases, or other information sources that federal, state, or local DG-4023, Page 8 agencies or conservation organizations maintain also may contain useful data. Analysts should use professional judgment to evaluate the applicability or possible obsolescence of the data. NRC staff will critically examine analyses using data that are more than two years old or data that do not accurately reflect existing conditions particularly if environmental conditions have changed in the past two years. Aquatic Habitat Identification Analysts should identify and describe aquatic habitats on the proposed site and adjoining property, as well as along any new or existing transmission line or pipeline corridors affected by the proposed action. The area of potential effects can extend beyond the proposed site to encompass habitats potentially affected by surface water drawdown or groundwater depletion (including dewatering for construction required to relieve pressure on temporary cofferdams during installation of intake/refill structures); thermal discharge; discharge of contaminants; siltation, noise, and pressure changes from in- water building activities; erosion, runoff, and sedimentation; cooling tower drift; habitat modification and loss; disposal of dredged material; and other activities. For cumulative effects, analysts should define geographic scale based on aquatic ecological parameters chosen according to the zone of influence while taking into account factors such as species migration routes (including those of diadromous species), upstream and downstream activities, locations of dams on waterways, and tidal influence. For example, a watershed scale may be appropriate. Analysts should identify aquatic habitats according to applicable federal, state, tribal, regional, and local nomenclature systems. Analysts also should identify and assess such habitats if they occur within the vicinity of the proposed and alternative sites. Table 1 lists some protected aquatic