Cook Plant preoperational studies 1970 / John C. Ayers ... [et al.].

each 0.1~, though we are aware of the weakness involved in estimating tenths
of a degree from the telethermometer dial. If we take plus-or-minus 0.1~ as
the uncertainty of our dial readings and consider as real only variations of
0.3~, the main features of the section still come through, but with loss of
detail (compare the section if only 12.7, 12.4, 12.1, and 11.8~ had been plotted
with the section that would have been given by 12.6, 12.3, and 12.0~).
In the bottom of the vertical temperature profile of Station 9 the temperature changed abruptly from 12.7~ to 12.5~. It is possible that the ship
drifted out of the rising column of warmest water while on the station, but
in so doing it seems impossible that, with readings spaced at one foot, it
could have missed getting at least one reading of 12.6~; we have consequently
considered that the alongshore subsurface current had bent the rising column
of warmest water out of the station vertical between the 5-foot and 6-foot
readings, and the section has been drawn accordingly.
It appears that a submerged outfall with diffusers does indeed entrain
substantial amounts of adjoining water on all its faces and that the horizontal
and vertical extent of its effect is minimal.
In Station 19 at the far end of the plume there was a very shallow lens
of water from 12.6 to 12.8~ floating on the surface in the upper foot of water.
Under the southeast wind of the day there was lakeward movement of warmer
surface water, with upwelling of colder subsurface water along the shore. The
substantial subsurface depth of temperature 12.50 at Station 19 is taken to
be offshore displacement of warm surface water by the wind, not as any effect
of the DuPont plume. Inshore temperatures of less than 12.0~ are indications
of upwelling of subsurface water.
There is no evidence that the outfall was discharging intermittently on
23 October. The vertical section along the plume may have missed a central
part of the plume, but if so there is nothing among the data to show where a