59 
one would predict from the oceanographic data available, that there 
would be an ample margin of safety against beach pollution. The 
extra volume of sewage to be discharged increases the coliform 
load by roughly one and one half magnitudes. Since the overall 
disappearance curve is exponential rather than arithmetic in 
character, the extra load would mean an increase of only about 
two hours for the counts to fall below the 10 per ml level, all 
other factors being equal. 
The dye patch data suggest that the rate of disappearance is 
not the same at the three outfalls, although the rates did not differ 
markedly between Orange County and Hyperion. If the disappearance 
curves for Hyperion and Whites Point in Figure 3 are extrapolated, 
they intersect the 10 per ml level at about 7 hours and 10 hours, 
respectively. Since the curves are based on single runs, these 
exact times cannot be taken too seriously. However, the slower 
disappearance of coliforms in these two areas, in the order given 
is also supported by the surface distribution, including the data 
from the two grids run at Hyperion. The "viability" studies done 
by the Los Angeles Sanitation District indicate a much slower dis- 
appearance around the Hyperion outfall as compared to either the rate 
we calculate from our dye patch experiment or to the rate around the 
Orange County outfall. The questions as to which rate should be 
used for estimating the situation that wuld exist around the pro- 
posed new outfall is discussed later. 
Orange County Beach Count Data 
The beach data in the vicinity of the Orange County outfall 
shows that coliform counts (from the Orange County Sanitation 
District) in excess of ten per ml occur fairly frequently and 
