Document: NRC Regulatory Guide
Document ID: c9ebcbb0-96c4-4d29-be51-5acae9cc858a
Document Type: regulatory_guide
Title: Estimating Aquatic Dispersion of Effluents from Accidental and Routine Reactor Releases for the Purpose of Implementing Appendix I (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740390.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.113
CFR Part: 
CFR Title: 

Content:
ps in records) at critical stations may subsequently be synthesized by direct cor relation with nearby streamflow stations or by statistical correlation with many stations using models such as "HEC-4, River Flow Simulation" (Ref. 60). In general, a period of at least 20 to 30 years of record, Including the historical drought of record in the region, should be used. Monthly durations have been found (Refs. 61 and. 62) to describe adequately the fluctuations in streamflow without introducing significant errors in long-term estimates of reservoir yields. Similarly, estimates of average annual radionuclide concentrations along a river, based on monthly streamflow averages, produced acceptable values when compared with longer flow periods (see Figure 17). Flow periods for multidirectional estuaries, lakes, and ocean sites were dis cussed in Sections 3 and 4 of this appendix. b. Usage The effects on streamflows at and downstream of a site caused by reservoirs or diversions should be identified. Reservoirs may cause significant changes in the distribution of seasonal runoff.' Operating constraints on reservoir storage, outflow, and diversions should be estab lished on a monthly basis for existing conditions of basin development and water demand and for anticipated future conditions throughout the lifetime of the plant. Where proposed reservoirs may significantly affect flow conditions, their effects should be considered by simulating their operation using models such as "HEC-3, Reservoir Analysis" (Ref. 63). Use types include drinking water, irrigation, process water (consumed by such users as breweries and soft drink manufacturers), recreation areas, and fisheries. Ground water users with wells whose zones of influence extend to streams should also be included. 1.113-41 A RES NO. 1 M & I, R, FC 42 DIVERSION NO. 2 IR 100 DIV. NO. 1 S'(FROM RES NO. 1) GAGE NO. 1 -4-.-(1961 - 1975) 34 (RETURN FROM SRES NO. 1. M & I) 4 4 GAGE NO. 3 (1916- 1975) 515 PLANTSITE 702 LEGEND A