Document: NUREG-0800
Document ID: aee3277d-bcab-4cf4-bdb2-fb607503b041
Document Type: srp
Title: PROBABLE MAXIMUM FLOOD (PMF) ON STREAMS AND RIVERS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340529.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.4.3
CFR Part: 
CFR Title: 

Content:
of that agency may be used in lieu of staff-developed analyses. In the absence of such assessments, both large and small basin PMP estimates by NOAA, published techniques of the World Meteorolo- gical Organization, and runoff, impoundment, and river routing models of the Corps of Engineers are used by the staff to estimate PMF discharge and water level at the site. A comprehensive review of the applicant's analyses will be performed and a simplified analysis using calculational procedures or models with demonstrably conservative coefficients and assumptions is performed. If the applicant's PMF estimates are within acceptable margins (described in subsection II), the staff positions will indicate concurrence with the applicant's PMF estimates and the SER input will be written accordingly. If the simplified analysis indicates a potential problem with the applicant's estimates, a detailed analysis using more realistic techniques will be performed. The staff will develop a position based on the detailed analysis; resolve, if possible, differences between the applicant's and staff's estimates of PMF design basis; and prepare the SER input accordingly. Wind-generated wave action will be independently estimated using Corps of Engineers criteria such as the."Shore Protection Manual." When sufficient water depth is available, the significant wave height and runup are used for structural design purposes, and the 1% wave height and runup are used for flood level estimates. Where depth limits wave height, the breaking or broken wave height and runup is used for both purposes. For condition 3 (i.e., a "dry site"--one not subject to stream flooding by virtue of local topographic considerations), the following procedures apply: 1. Use Corps of Engineers PMF estimates for other sites in the region to develop "regional drainage area vs. PMF discharge (cubic feet per second/square mile)" data, for extrapolation to the site. 2. Envelop the above data points to obtain an estimate of