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little problem, since the thermal plume generally does not influence 

 bottom waters to a measurable extent. The "Analysis of Impacts" portion 

 of the Hydrographic section (Section 3.0) indicates that the thermal 

 plume is essentially a near-surface feature. Even in the area of the 

 discharge, bottom waters are usually close to ambient. The maximum 

 observed temperature increase for bottom waters in the area of the 

 discharge was approximately 2°F and bottom- temperature elevations of 

 this magnitude are uncommon. For this reason impacts on the epibenthos 

 in New Haven Harbor as a result of artificially elevated water temp- 

 eratures and sudden cooling of the water when the plant goes off-line 

 can be expected to be minimal. 



Entrainment of eggs and larvae of epifaunal organisms has the 

 potential for serious impact on the epibenthic community. This is 

 particularly true for resident species that reproduce within the limits 

 of the harbor. For these species, chronic destruction of a portion of 

 the egg and larval stages could eventually result in observable decreases 

 in the population. We do not, however, consider entrainment of eggs and 

 larvae of the epibenthic invertebrates in New Haven Harbor to present a 

 serious threat to the epibenthic community for two reasons. First, 

 based on annual meroplankton abundances in New Haven Harbor (Section 

 4.0), and to some extent the behavioral tendencies of the epibenthic 

 organisms, it appears likely that Long Island Sound supplies the major 

 sources of eggs and larvae and that, as indicated previously, no major 

 spawning occurs in the harbor. Secondly, assuming 100% mortality of 

 entrained eggs and larvae, because of the comparatively small cooling 

 water flow of the New Haven Harbor plant (0.7% of the average tidal flow 

 rate) and the large exchange of harbor water with Long Island Sound 

 (assumption based on a tidal prism of 43% of the harbor voliome at MSL 

 coupled with a general LIS net flow pattern past the harbor mouth) , it 

 is reasonable to assume that only a minute percentage of the eggs and 

 larvae present in the harbor pass through the power-plant cooling sys- 

 tem. This amount is wholly insignificant in comparison to the quantity 

 of eggs and larvae that move in and out of the harbor with the tides. 



