How Do You Determine When a
Stream is Polluted?
W. E. HOWLAND
Professor of Sanitary Engineering
R. B. Wiley
Head, School of Civil Engineering and Engineering Mechanics
Purdue University
It is not certain that this paper will answer the question, How do
you determine when a stream is polluted? It will state and illustrate
certain general principles that will help to decide whether or not a
given stream is of such poor quality as to require improvement, or to
determine the extent of treatment to be given to municipal or industrial
wastes before discharge into the stream. If this is deciding whether or
not a stream is polluted, then our title is appropriate—otherwise not.
For the exact meaning of the word "pollution" is, like that of so
many others, quite elusive. The dictionary does not help a great deal.
It says in part that to pollute is "to make or render impure or unclean,
to impair or destroy the purity of; to defile; desecrate; profane; corrupt ;
befoul, as to pollute a water supply, specifically by the introduction of
sewage." It does not say whether or not that sewage may have been
treated or, if so, to what extent. It does not mention industrial wastes.
Other authoritative sources of definitions are also lacking in definiteness.
To be consistent with the title, we choose to define pollution as an
unwarranted or unreasonable amount of objectionable substances contributed to the natural water of a stream which, therefore, because of
their amount and kind, should somehow be removed or counteracted by
someone or prevented from entering the stream.
Surely the important question to be decided is, "What constitutes
unreasonable contamination?" and not merely, "What does the letter of
the rule or statute precisely require?" For the final test of the action
taken must ultimately be that of reasonableness, whether the test is
made before the court of law or the bar of public opinion.
The Indiana Stream Pollution Law of 1943 states that a city or
industry can appeal to the circuit or superior court from an order of
the board. Either party can demand a jury trial. The court then has
power "to determine whether said order is reasonable or unreasonable,
and whether a polluted condition of any water or waters exists or is
about to exist, and to affirm, modify, or wholly set aside such order,
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