MICHIGAN ACADEMY OF SCIENCE. 
119 
SHALL POLLUTION OP MICHIGAN STREAMS BE PERMITTED? 
M. O. LEIGHTON.* 
As the subject of this paper is in the form of an interrogation, the 
discussion will be commenced with a direct answer: Yes, Michigan 
streams must be polluted. In spite of all the preventive measures pos¬ 
sible under ideal legislation, enacted by an ideal legislature, Michigan 
streams must inevitably be polluted; there is no alternative from this 
conclusion. Let us review the facts briefly. 
The water which flows in a stream is largely derived from the land 
lying above. The rain falls upon the ground and either runs directly 
off into water courses or sinks into the ground, to reappear in the form 
of springs or as seepage, so that ultimately, nearly all the precipitation 
is drained off into rivers. It is well known that water is an excellent 
solvent; as it passes over and through the ground, it dissolves larger 
or smaller quantities of those substances with which it comes in contact. 
If it passes through a bed of salt, for example, it will, when it emerges, 
contain some of that salt, or if it encounters filthy conditions, it will 
contain an abnormal amount of organic matter. Therefore, it may 
safely be said that the character of any stream water affords an excellent 
record of the conditions through which it has passed. 
Streams draining primeval countries carry what is known as “nor¬ 
mal” water, or what is more popularly called “pure” water. What¬ 
ever of organic matter such water may contain, consists of the products 
of decay of vegetable matter. But when man moves upon that drainage 
area and sets up his establishments, the water draining over and through 
the land which he occupies must of necessity acquire characteristics 
which it hitherto did not possess. Such water will contain, in addition 
to the vegetable organic matter, the products of the decay of animal 
matter, and just here we have what may be called “initial” pollution. 
It is but a short step from the exceedingly minute and immeasurable 
amount of pollution imparted to run-off waters by one inhabitant, to 
the large amount which must be the necessary result of drainge of the 
land occupied by many persons, and so it is, that we may accept the 
statement as final and axiomatic that no river water can remain un¬ 
polluted so long as its drainage area is inhabited. It may, of course, 
have so small a population per square mile, and the habits of that popu¬ 
lation may be so regulated that there will be no measurable effect upon 
the run-off; but the effect is there nevertheless. 
When, however, we take up the consideration of a stream that drains 
a populous basin, that has cities and villages upon its banks, like most 
of those in which we are interested, we may be perfectly sure at the 
outset that just as long as those cities and villages remain there, the 
* Hydrograplier In Charge, Division of Hydro-Economics. 
