contrast to the previous case where the most turbid water 

 occurred at high tide. Another period of clear water occurred 

 from 2130 to 0200, After the first intrusion of clear water, 

 the upper or near-surface half of the water column remained 

 clearer than the lower half. 



1200 1400 1600 1800 2000 



Figure 6, Time (hours) - depth (feet) 

 plot of water transparency at the 

 USNEL tower on 14 July 1960. The 

 numbers on the contours between 

 shaded areas represent the per cent 

 light transmitted through one-half- 

 meter of water, at that depth and 

 time. Time of high tide (HT) is 

 indicated along the surface. 



Figure 7. Time-depth plot of water transparency at the 

 USNEL tower on 19-2 July 1960. Times of high tide (HT) 

 and low tide (LT) are indicated along the surface. 



2-3 August 1960 (fig. 8) 



This 27-hour series was characterized by an intensely 

 turbid layer near the surface and patches of turbid water 

 with transparency of less than 20 per cent. The subsurface 

 turbid layer was present at the beginning of the run and the 

 turbidity increased with time, especially between depths of 

 10 and 20 feet. After 1500 the entire water column had a 

 transparency of less than 6 per cent. There was a tendency 

 for deeper turbid layers between low tide and the following 

 high tide. In general, the entire water column remained 

 fairly turbid, with maximum turbidity just below the surface. 



13 



