38 
direction, gives the "best fit" curve shown in Figure 6. This 
curve shows a decrease in coliforms to about ten per ml in a 
distance of 6,000 feet from the outfall. Of the 35 samples taken 
from the VELERO IV at greater distances from the point of sewage 
discharge, none gave counts of over 10 per ml. An inspection of 
Figure 3 shows that the average coliform counts in the dye patch 
experiments decreased to about 10 per ml in roughly six hours. 
If one assumes that the sewage field is moving at the rate of 
1,000 feet an hour (0.2 knot}, a value that roughly corresponds 
to the observed rate of movement of the dye patches, then there 
is a good correspondence between the dye patch data and the surface 
sample data. Plotting the dye patch data on the basis of this 
assumption gives a curve (Fig. 6) that is somewhat higher than 
the surface distribution curve. Since the surface distribution 
curve is based on some points that were probably not in the main 
sewage field, one would expect it to show a more rapid decrease 
than that found along the main direction of sewage flow as measured 
by the dye patches. 
No attempt was made to map the surface field arowd either 
the Whites Point or Hyperion outfalls, but surface samples were 
taken with the vertical profiles in these areas. The data show 
a decreased count with distance, although the results were more 
variable than at Orange County and the rate of decrease was not as 
rapid. Thus, counts greater than 2,000 per ml were found 9,000 
feet away from the Hyperion outfall and counts of greater than 
200 per ml were observed 12,000 feet from the Whites Point out- 
fall. In the area of the latter outfall, visible patches of 
greasy slicks were observed on the sea surface as much as four 
