Pollution-Capacity Studies of
the Wabash River
Robert K. Horton, Sanitary Engineer
Ohio River Valley Water Sanitation Commission
Cincinnati, Ohio
A pollution-capacity study, quite unlike previous stream surveys,
has been undertaken on the Wabash River.   The work is featured by:
1. Intensive sampling over a short period of time in order to pro¬
vide the proper data for later statistical analysis. The actual
period of sampling was twenty-five days.
2. The opportunity to coordinate the special skills of nine different
agencies to expedite the work.
3. Application of theories of probability so that a series of variables
could be projected to a knowledge of conditions in the river
under varying circumstances of flow, pollution loading, and river
quality.
Serious pollution of the Wabash River, resulting from the discharge
of untreated domestic and industrial wastes, has existed for a number
of years. As long ago as 1931, public health officials showed special
concern for that stretch of the river immediately below Terre Haute,
Indiana. In that year, the health departments of Indiana and Illinois
undertook a joint survey of the Wabash from Terre Haute to Mt.
Carmel, Illinois. Studies were continued during the three following
years, as well as in 1940, 1946 and 1948. All of these surveys, from
1931 to 1948, showed evidence of gross pollution. However, these
surveys did not furnish all the information required to make precise
determination of the capacity of the river to assimilate pollution.
Capacity of a river to assimilate pollution depends upon the rate at
which self-purification occurs. This rate, in turn, is governed by many
factors (topography, climatic conditions, runoff pattern, etc.), and is
subject to the widest kind of variation. Therefore, unless careful evalua¬
tion is made of all these factors of self-purification, it is virtually
impossible to establish an economical basis for waste-treatment require¬
ments. If a remedial program is not designed to make full use of the
river's capacity for absorbing wastes, there can be no assurance that
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