We may rationalize the use of the Great Lakes for disposal of domestic 
and industrial sewage by saying that the great quantities of water in the Lakes 
will dilute this sewage beyond the injury point. In this we can be very wrong. 
In the first place, the effect of sewage disposal is largely in the important 
shallow water areas. In the second place, sewage disposal may be in bays or 
other circumscribed areas where the dilution factor is small and certain wa- 
ters can be converted into cesspools. All industrial sewage should be most 
carefully tested for possible injury to lake life, and tolerances established. 
The fact that an industrial effluent containing one part per million of deleteri- 
ous material may not be injurious takes on new meaning when we increase the 
amount of effluent threefold in some partially isolated area. 
Some species of fishes are dependent on streams for spawning and rear- 
ing their young. According to Langlois (1945), changes in fish populations in 
Lake Erie may have been due to the loss of such areas. Early records, he says, 
show that pickerel and muskellunge at one time ascended in the spring such riv- 
ers as the Huron, Maumee, and Sandusky for spawning purposes. Now such 
things as waste from an alkali plant, and greasy sludge, have established chem- 
ical barriers to fish movement. Silt, he further states, is particularly harmful. 
At the mouths of the Raisin, Maumee, Portage, and Sandusky rivers, silt depos- 
its have eliminated most of the rooted vegetation by cutting off light, and con- 
sequently photosynthesis, and by actually suffocating plants through deposition 
of silt on their surfaces. The silt deposits have destroyed breeding grounds for 
several fishes and food for waterfowl, and the absence of these ‘‘aquatic mead- 
ows’’ has allowed increased wave action, which is cutting into the banks at the 
rate of 2 feet a year in Some areas and much more in others. For example, at 
the Ohio-Pennsylvania line a clay bluff was cut back from 10 to 20 feet in one 
storm on November 2, 1942. Here is an interesting chain reaction: The tilling 
of soil in the watershed released silt, which washed into the rivers and was de- 
posited in the estuaries, thereby destroying rooted aquatic vegetation, thereby 
increasing wave action, which greatly accelerated the erosion of the shore line. 
The physical environment has changed in other ways. There have been 
diversions of waters, both into and out of the Great Lakes. The out-diversion 
at Chicago is well known. By law this flowage is limited to 3,100 cubic feet per 
second (1,500 c.f.s. direct flowage plus 1,600 c.f.s. domestic pumpage). My. 
personal reaction to such regulation, even when approved by the Supreme Court, 
is that, wherein it is specific, rigid, and unchangeable, it is not based on good 
common sense. It reminds me a little of the man who, upon having trouble with 
his arithmetic, introduced a bill into a state legislature to make pi equal 3.0 in- 
stead of the more cumbersome 3.1416. It is well to legislate limits rather 
broadly, whether it be in the outflow of waters from Lake Michigan or the fish 
and game harvest. Changing conditions make specific legislation a precarious 
thing, and within limits someone should have the responsibility of fitting regula- 
tions to changing conditions. The limit of 3,100 c.f.s. is an arbitrary one, and, 
if we think this flowage greatly reduced the high water levels of 1952, we are 
not realistic. 
There is also new flowage into the Great Lakes. In 1937, a diversion of 
