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

with a thermistor chain of one-foot spacing. Navigation was by sextant fixes
to landmarks ashore.
The stations occupied on the 28th are shown in Figure 2. Station MCP-10
was set well off to windward to sample the ambient inshore lake water coming
into the vicinity of the plant outfall. Temperature there was 21.0~C at the
surface. On this day the intake temperature was 18.0~C and the temperature at
the mouth of the outfall channel was 25.2~. Deterioration of surface temperature
was rapid; at about the mid-length of the harbor temperatures ranged from 19.8~
to 22.4~.
By comparison to the surface temperature at Station MCP-10, Stations MCP-12
and 14 probably had no heat contribution from the plant plume while Station MC1I13 at 4000 feet from the outfall appears to have had 0.5~C in the upper one foot
remaining from the plant plume. This represents 0.5/7.2 or 7% of the heat added
by the plant; the other 93% having been lost in 4000 feet.
The surface isotherms are plotted in Figure 3 and in Figures 4 through 11
are plotted the subsurface isotherms observed at each foot of depth. Depths
and temperatures for each station also are tabulated in Table 1. Stations drop
out of these maps when water depth becomes less than the depth being plotted.
Water temperatures in the vertical diminished rapidly with increase of depth,
and by eight feet the temperature condition in the harbor was probably an effect
of the river outflow rather than an effect of the plant plume.
Biological samples as follows were collected from the Michigan Citv plume
and its environs:
Phytoplankton: Station MCP-16 in the intake, Station MCP-1 in the
outfall mouth, Station MCP-3 in the axis of the plume about
400 feet from the outfall mouth, and Station MCP-8 slightly
outside the axis of the plume at about a thousand feet from
the outfall mouth.

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