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

D. EFFECTS OF EXISTING THERMAL DISCHARGES ON LOCAL ICE BARRIERS

Concerned citizens, in opposing the construction of power generating stations, commonly raise the point that the plants' discharges of waste heat will
"melt the shore ice and allow the winter waves to produce added erosion of our
beaches." During the past two winters we have spent substantial time and effort to ascertain from existing thermal discharges the degree to which there
is evidence for their fear.
During these two winters we have: 1) carried out aircraft flights over the
shores and thermal plumes of Lake Michigan; 2) maintained a scheduled photographic surveillance program to record the shore ice conditions at the Cook
Plant site; and 3) carried out on-foot photographic expeditions to record changing ice conditions at the Cook Plant site and at the sites of existing thermal
discharges. Winter operations of 1969-70 constitute Part V of our report series.
From these activities we have derived abundant evidence that the shore ice
along the Michigan shore has the complex structure that Marshall (1966, Fig. 28)
called "the storm icefoot, lagoon, and outer barrier." The method of formation
of this compound structure, and details of what the structure is, are discussed
in Section C of this report.
Our data indicate that the concerned citizens are probably speaking of
Marshall's complex of inshore ice structure which is present and frozen solid
with sufficient consistency to be probably the one upon which they have walked,
and from which they have drawn their correct conclusion that it protects the
beach from winter wave action.
The icefoot consists of two to four ridges of ice very close to shore.
*
Marshall, E. W. 1966. Air photo interpretation of Great Lakes ice features.
Special Report No. 25, Great Lakes Research Division, University of Michigan, Ann Arbor, Mich. ix and 92 pp., 64 figures.
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