Document: NUREG-1555
Document ID: b5d0daf9-9138-4935-a8fb-b1fed4498171
Document Type: esrp
Title: DISCHARGE SYSTEM
Source: NUREG-1555
Source URL: https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1555/initial/
Revision Date: 2007-10
Chapter: 5
Section ID: 5.3.2
CFR Part: 
CFR Title: 

Content:
sary for sustaining actively growing and reproducing populations if the maximum weekly average temperature in the zone inhabited by the species at that time does not exceed one-third the range between the optimum temperature and the ultimate upper incipient lethal temperature of the species, and the temperatures above the weekly average do not exceed the criterion for short term exposures. ` After the specific limiting temperatures and exposure times have been determined by studies tailored to local conditions, the reproductive activity of selected species should be protected in those areas in which (1) temperature regimes required for gonad growth and maturation are preserved, (2) no temperature differentials are created that block spawning migrations, although some delay or advancement of timing based upon local conditions may be tolerated, (3) tempera- tures are not raised to a level at which necessary spawning or incubation temperatures of winter spawning species cannot occur, (4) sharp temperature changes are not induced in spawning areas, either in mixing zones or in mixed water bodies (the thermal and geographic limits to such changes will be dependent upon local requirements of species, including spawning microhabitat, e.g., bottom gravels, littoral zone, and surface strata), (5) timing of reproductive events is not altered to the extent that synchrony is broken where reproduction or rearing of certain life stages is shown to be dependent upon cyclic food sources or other factors at remote locations, and (6) normal patterns of gradual temperature changes throughout the year are maintained. ` Nuisance growths of organisms may develop where there are increases in temperature or alterations of the temporal or spatial distribution of heat in either the receiving water bodies (e.g., rivers, lakes) or in onsite cooling ponds. Some nuisance conditions may be created by operation of cooling ponds that may not affect receiving water body biota, but that may affect