The Five Minute Solution Revisited — Stream Load
Allocations on the Houston Ship Channel
A.W. BUSCH, Vice President
Environmental Affairs
Southwest Research Institute
San Antonio, Texas 78284
BACKGROUND
This is a success story of a cooperative Federal State pollution abatement program.
The combination of time, legislation enactment, changing viewpoints and demonstrated
technology allowed quantification to supplant opinion. The time span was 4'/2 years and
shows clearly that our world is a dynamic one and that change can be implemented at an
appropriate rate when issues are quantified properly.
In 1967 the Texas Water Quality Board (TWQB) reported aggregate oxygen demand
discharged into the Houston Ship Channel by industry and municipalities to be 430,000 lbs
per day. The Board instituted a pollution abatement program along with a 3 year study to
define the needed total reduction.
In March, 1970, with the study still in progress, the writer projected that intentional
(permitted) discharges to the Houston Ship Channel should be limited to an aggregate
35,000 pounds of oxygen demand per day, based on maintaining 4 mg/1 dissolved oxygen
(1). The simplistic basis for this arithmetical calculation was common sense recognition that
all of the complicated equations for predicting dissolved oxygen concentration really
express an equivalence between two rates of reaction; deoxygenation and reaeration.
Further, it is clear that for policy enunciation and permit writing only the "worst case"
condition is pertinent because oxygen can be consumed in a stream only at the rate at which
surface reaeration supplies it. Therefore, a quick solution for stream assimilative capacity to
be assigned for intentional pollution is the product of the minimum surface (mass) transfer
coefficient, the maximum dissolved oxygen deficit to be allowed and the surface area under
consideration (See Figure 1). Subsequently this concept was published in some detail (2, 3,
4).
SUBSEQUENT DEVELOPMENTS
Substantial progress had been made in the TWQB pollution abatement program by
late 1971, but the study to define reduction needs was not yet completed. At that time the
U.S. Envirommental Protection Agency convened an enforcement conference based on a
report from the Denver arm of the Washington Enforcement Office of EPA and supporting
the figure of 35,000 lbs per day of oxygen demand.
In mid 1972, mutually cooperative efforts were initiated between the Region VI EPA
office and the Texas Water Quality Board to update discharge information, one of the
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