2.4 
2.1 - 
1 . 8 - 
1.5- 
t e 12 “ 
"-o 
0.9- 
0 . 6 - 
0.3- 
0 . 0 -- 
0 
Figure 9.3. Median monthly light attenuation coefficients from the continuous data set at 5 locations in 
Yaquina Estuary (1999-2003). 
9.2 Percentile Approach for Water Clarity and TSS 
Due to methodological differences (NCA data set) and missing data (Classification data set), 
we calculated CDFs for light attenuation for only the Yaquina Estuary data sets. During the wet 
season, there is not a significant difference between light attenuation coefficients (kj) computed from 
the continuous and cruise data within each zone (Table 9.1; Mann Whitney Rank Sum, p>0.05). 
During the dry season, the light attenuation coefficients computed using the continuous data are 
significantly higher than those computed from the cruise data (Mann Whitney Rank Sum, p<0.001), 
and this difference is greater in Zone 2 (median about 16% higher for continuous) than in Zone 1 
(median about 8% higher). Median light attenuation coefficients within Zone 1 during the dry season 
were significantly higher (5-8% for continuous and cruise data, respectively) than those from the wet 
season (Mann Whitney Rank Sum, p<0.05). Within Zone 2, median light attenuation coefficients were 
significantly higher (10-27% for cruise and continuous data, respectively) in the dry season than in the 
wet season (Mann Whitney Rank Sum, p<0.001). 
i- 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 - 1 -r 
1 2 3 4 5 6 7 8 9 10 11 12 
Month 
62 
