Winter operations, 1970-1971 / John C. Ayers, Norbert W. O'Hara, William L. Yocum.

Grand Haven. 17 March 1971.
In both the latter cases the basic shore ice structure is nearly breached,
a condition more advanced than observed at Bailly station.
The evidence available to us from our ice studies during the winters of
1969-70 and 1970-71 does not show that discharges of waste heat cause extensive melting of shore ice with resulting exposure of the beaches to wave erosion,
as claimed by concerned citizens.
Instead, our data show that the usual outfall structure, a sheet-pile flume
leading out into the water, will have shore ice continuing up to the very sides
of the flume. The unconfined outfall channels of Big Rock and Campbell stations
have, in both winters, shown different behavior. Big Rock each winter melted a
narrow channel of limited length outward into the solid sheet ice of Little
Traverse Bay and shore ice came up to the very edges of the outfall canal. At
Campbell there has been, both winters, a considerable area of shore ice melted,
but beach erosion has not been evident; perhaps the current from the discharge
channel lessens the strength of wave action.
The unconfined natural mouths of even small streams appear to be capable
(without man-made heat) of destroying substantial amounts of the protective shore
ice. We believe that the apprehension the concerned citizens express has resulted from their observations of ice destruction at the unconfined mouths of
natural streams. Reasoning from the consistency with which even short outfall
flumes at power stations have protected the shore icefoot, we suggest that the
concerned citizens could beneficially agitate for the construction of shore discharge flumes at presently unconfined stream mouths.
The Probable Effect of the Cook Plume on the Local Ice Barrier
The whole thrust of our studies of the ice barrier in the area of the Cook
Plant site has been to obtain a background of information and experience from

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