Cook Plant preoperational studies, 1969 / John C. Ayers ... [et al.].

by the presence of silt, with its concommitant detrital food materials in the
sand than by any influence of the plant's thermal plume.
So far as benthos indicate, it appears that wave action and current scour
from the plant's discharge of condenser cooling water are dominant features over
a limited shallow-water portion of the harbor, but beyond this local area the
benthos do not appear to sense the presence of the plant's cooling water.
In summary, on 28 June 1969 the waste heat from the Michigan City Generating
Station did not appear to affect the benthic organisms. The plankton results
may have been influenced by water masses drifting in from the southwest.
Waukegan, Illinois, Light Wind
On 30 June 1969 the R/V MYSIS conducted a survey of the thermal plume from
the Waukegan Generating Station. The wind was from the west-southwest at 2 mph,
but south winds of 18 mph had blown during the preceding afternoon and evening
and the plume was moving northward along the shore under the residual current
from the preceding south wind.
The plume could be traced to a point two miles north of the outfall. Lakeward its greatest extent was about 3000 feet, with the last third of this length
being only about 1000 feet wide.
Intake temperature was 12.8~ and outfall temperature was 16.6; these are,
respectively, the surface temperature outside a fish net strung across the intake,
and the surface temperature at the point where the MYSIS went aground in 7 feet
of water as she moved up the outflow channel.
A surface thermistor trailing from the ship's bowsprit was used to determine
whether we were in or out of the plume. All station data were taken with an
additional thermistor chain spaced at one-foot intervals. Navigation was by
radar ranges and bearings.

-26 -