THE FATE OF COLIFORM BACTERIA IN THE VICINITY 
OF THE ORANGE COUNTY, LOS ANGELES COUNTY, 
AND HYPERION SEWER OUTFALLS 
An Interim Report 
INTRODUCTION 
During the early stages of an oceanographic survey of Santa 
Monica Bay it was noted that ocean current velocities over the 
central part of the continental shelf were low and variable. 
Velocities rarely exceeded 0.35 knot and the average was 0.2 
knot. The direction of flow was also quite variable for periods 
of time greater than 2 hours, so that the net water motion was 
approximately 0.1 knot. The dominant direction of flow extending 
over periods of several days was generally shoreward with digres- 
sions due to winds, tides, and local man-made phenomena, 
The slow transport of water over the central part of the 
shelf required modification of the philosophy of sewage discharge 
into the bay. It had been considered that if the outlet were 
placed five miles from the nearest shore and if mechanical dif- 
fusion of the effluent would producs an initial dilution of 1/1000, 
then the initial bacterial population would be low enough to allow 
health standards to be met if sewage reached the surf zone. How- 
ever, because of the low volumes of sea water passing the pro- 
posed discharge site, an initial dilution greater than 1/100 
should seldom occur regardless of the efficiency of mechanical 
diffusion. 
It was necessary, therefore, to determine with a reasonable 
degree of accuracy the rate at which coliform bacteria dis- 
appeared from sea water after their introduction with the 
