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:
another flood-producing phenomenon exceeding the staff estimate of PMF water levels. For condition 3, the site grade must be well above the staff assessment of PMF water levels. The evaluation of the adequacy of the margin (difference in flood and site elevations) is generally a matter of engineering judgment. The judgment is based on the confidence in the flood level estimate and the degree of conservatism in each parameter used in the estimate. 2.4.3-2 Rev. 3 - April 1989 Appropriate sections of the following documents are used by the staff to deter- mine the acceptability of the applicant's data and analyses. Regulatory Guide 1.59 provides guidance for estimating the PMF design basis. Regulatory Guide 1.29 identifies the safety-related structures, systems, and components, and Regulatory Guide 1.102 describes acceptable flood protection to prevent the safety-related facilities from being adversely affected. Publications of the National Oceanic and Atmospheric Administration (NOAA) and the Corps of Engineers may be used to estimate PMF discharge and water level condition at the site and coincident wind-generated wave activity. III. REVIEW PROCEDURES For conditions 1 and 2 (described in subsection II), the methods used for evaluating flooding potential are separated into two parts--PMF on adjacent streams and local PMF. The review procedure is outlined in the attached Figures 2.4.3-1 (for PMF on adjacent streams) and 2.4.3-2 (for local PMF). (The procedure for evaluating the adequacy of site-drainage facilities based on a local PMF is outlined in SRP Section 2.4.2.) Corps of Engineers PMF assessments for specific locations or generalized PMF assessments for a geographical area approved by the Chief of Engineers and contained in published or unpublished reports of that agency may be used in lieu of staff-developed analyses.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