Studies on water movements and sediments in Southern Lake Michigan : part 1[-3] ... / by John C. Ayers.

Supplemental Sediment Studies

Oily Sediments off Gary, Indiana
In May 1964 the areal extent of the oily sediments off
Gary, Indiana, which were reported in Part II of this Final
Report, was worked out in detail by R/V MYSISa
Figure 17 gives the extent of these sediments. They occupy
an area about four miles long by about 1-1/2 miles wide oriented
in a northwest-southeast direction and lying to the east and
south of Buoy R2 off Gary.
These sediments are primarily of oily silty sand. They
do not show any continuation to the shore. The nature of these
sediments is very similar to that of sediments collected from
a known spoil-dumping area off Milwaukee at 42059.5S 87047.09
We now believe that the sediments off Gary are also spoil
(dredgings) from harbor dredging operations along the southern
end of the lake. As spoil, these sediments represent a manmade modification of the lake environment but not one that can
be attributed to the eutrophication process in the sense in
which that term is usually used.
Foul-Odored Sediments off Calumet Harbor
In May 1964, also, the MYSIS made a detailed search for
the foul-odored sediments which had previously been found off
Calumet Harbor, and which were reported in Part IIo
No evidence of these foul-odored sediments was found. The
condition that was present during the bottom survey reported
in Part II was, then, a temporary condition for which no cause
can be given.

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