Document: NRC Regulatory Guide
Document ID: c7b1689b-ff17-4083-9fb1-f91b6965ea1a
Document Type: regulatory_guide
Title: Design Basis Floods for Nuclear Power Plants + HISTORY - HISTORY 02/2022 – DG-1290 , Proposed Revision 3 09/2014 – Periodic Review of Revision 2 – Revise 07/1980 – Errata to Revision 2 07/2024 – DG-1290 Revision 1 (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740388.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.59
CFR Part: 
CFR Title: 

Content:
d meridian. B.3.1 Use of PMF Discharge Determinations The PMF peak discharge determinations listed in Table B.I are those computed by the Corps of Engineers, by the NRC staff and their consultants, or computed by applicants and accepted by the staff. For a nuclear facility located near or adjacent to one of the streams listed in the table and reasonably close to the location of the PMF determination, that PMF may be transposed, with proper adjustment, or routed to the nuclear facility site. Methods of trans. position, adjustment, and routing are given in stan dard hydrology texts and are not repeated here. B.3.2 Enveloping Isollnes of PMF Peak Discharge B.3.2.1 Preparation of Maps For each of the water resources regions, each PMF determination in Table B.A was plotted on logarithmic paper (cubic feet per second per square mile versus drainage area). It was found that there were insufficient data and too much scatter west of about the 103rd meridian, caused by variations in precipitation from orographic effects or by melting snowpack. Accordingly, the rest of the study was confined to the United States east of the 103rd meri dian. For sites west of the 103rd meridian, the methods of the preceding, section may be used. Envelope curves were drawn for each region east of the 103rd meridian. It was found that the envelope curves generally paralleled the Creager curve (Ref. 2), defined as Qi,46.0 CA (0.894A -0.048) -1 where Q is the discharge in cubic feet per second (cfs) C is a. constant, taken as 100 for this study A is the drainage area in square miles. 1.59-12 K Each PMF discharge determination of 50 square miles or more was adjusted to one or more of the six selected index drainage areas in accordance with the slope of the Creager curve. Such adjustments were made as follows: PMF Within Drainage Area Range, sq. mi. 50 to 500 100 to 1,000 500 to 5,000 1,000 to 10,000 5,000 to 50,000 10,000 or greater Adjusted to Index Drainage Area, sq. mil. 100 500 1,000 5,000