29 
and 17,000 feet from the outfall, and the C stations between 
23,000 and 27,000 feet away. For the purposes of the further 
discussion it will be assumed that the B stations along these 
two lines are 3 statute miles (15,800 feet), the C stations 5 
miles (26,400 feet), and the surf zone 53 miles (29,000 feet) 
from the outfall. 
In order to make any predictions, the following information 
must be available; (1) the rate of disappearance of coliforms, 
(2) the initial coliform content at the boil, and (3) the rate 
of travel to the surf zone (or any other point away from the 
boil for which prediction is desired). Each of the above 
factors are variable and aithough average values can be assigned 
for each, the extreme situations must be considered as well as 
the average situation. 
The average disappearance rate of 90% reduction in 3 hours 
can be accepted as typical under the conditions that we studied. 
No individual dye patch showed a disappearance rate of greater 
than 43 hours for 90% reduction, and this value is therefore 
used for the “worst" situation. It is possible that slower 
rates might occur on some occasions, but there is no way of 
predicting the frequency of such occurrences from our data, if 
they do occur at ali. 
Various estimates can be made of the coliform population 
at the boil depending on the data employed. Ome could accept 
the geometric mean of the twelve samples we collected in the 
boil during discharge of primary effluent, 36,000/ml, as also 
applying to the situation that would exist around the proposed 
outfall. However, since an initial dilution of at least 1/60 is 
