Year Mean, m 
7.0 *—* 1991 2.3 
: e----0 1980-91 2.1 
Water Visibility, m 
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 
Month 
Figure 20. Daily water visibility values with monthly means 
Density 
56. Daily and monthly mean surface density values, plotted in 
Figure 21, were measured with a hydrometer. Monthly means are also given in 
Table 8. 
48 
