Document: NUREG-0800
Document ID: 496b5bd8-c9a2-4cf6-a703-e41c51e155ec
Document Type: srp
Title: CHANNEL MIGRATION OR DIVERSION
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1819/ML18190A201.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.9
CFR Part: 
CFR Title: 

Content:
analysis, the staff should concur with the applicant’s findings. If the staff’s preliminary bounding analysis indicates that its analysis and that prepared by the applicant are not comparable and reach different conclusions, the staff should repeat its analysis using more realistic assumptions; it may also be necessary to rely on more sophisticated analysis model. If the results of the two analyses continue to remain non-comparable then the staff should analyze the applicants’ data, methods, and assumptions to determine their reasonableness. Staff may also rely on alternative analysis techniques including alternative conceptual models. Staff should also consider the need to conduct an audit with the applicant to address any differences with the applicant’s findings. Staff should be aware that there generally are no well-established predictive methods for evaluating the potential for the migration of natural watercourses in riverine environments. However, the potential for this hazard to exist at a particular location can be inferred by reviewing certain types of empirical earth-science information. Topographic maps, geologic maps, aerial photographs, and satellite imagery can be examined for evidence of past channel migration as they are generally recognized to reflect evidence of the meandering (lateral movement) of naturally-flowing water conveyance features. If there were evidence of such behavior in the past, this would be apparent based on inspection of the maps and/or 2.4.9-10 Draft Revision 4 – September 2018 photographs reviewed.6 The particular geomorphic features of interest generally include but are not limited to meander belts, flood plains, oxbow lakes, natural levees, and the like. [These features are defined and illustrated in Fairbridge (1968), for example.] The U.S. Geological Survey’s (USGS’s) historic topographic map geospatial database7 can be accessed to identify the earliest maps published for the area and then inspecting those