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:
s of predicting the consequences of channel migration potential near structures when the alignment of a natural river is artificially modified. 3. Flooding Effects Associated with Channel Migration or Diversion: Should channel migration or diversion be found to be consequential at a site, the estimated flood elevation prepared by the applicant should be evaluated. Water wave elevations should be reported to the nearest tenth of a foot. The geodetic reference datum used by the applicant to report the water surface elevation should also be specified. The analysis should account for the effects of flood inundation and drawdown at the site. This information should be communicated in the form of an inundation map.9 The extent and duration of wave run-up during the inundation phase of the flooding event should also be reviewed. Separate flooding levels, corresponding to different locations within the powerblock, need to be reported as the flood water elevation may vary spatially owing to differences in the finished site grade and the presence of multiple as-built reactor structures. In general, this aspect of the staff’s review is similar to that described in SRP Section 2.4.3 “Streams and Rivers.” The geographic layout of existing channel meanders, cross-sections (widths and depths), profiles (slopes), estimated discharge properties (velocity and energy), and material compositions for beds and banks and, suspended loads should be evaluated. The staff will also need to review the following as it relates to SSCs important to safety: the static, wave, and dynamic force metrics, including the maximum inundation and drawdown depths, current speed, acceleration, inertial component, and momentum flux that quantify the anticipated forces; the debris and water-borne projectiles that accompany anticipated flood-generated currents; and the effects of sediment erosion and deposition caused by flooding that may result in blockage or loss of function. For any diversion,