0 20 40 60 80 100 
Percentage of Area/Volume Exceeding the Criteria 
Figure VI-21. Cumulative frequency distribution of spring (March-May) chlorophyll a 
concentration exceeding the 95 th percentile phytoplankton reference community 
values (a) compared with the normal distribution curve (b). 
Figure VI-22. Cumulative frequency distribution of summer (July-September) chlorophyll 
a concentration exceeding the 95 th percentile phytoplankton reference community values 
(a) compared with the normal distribution curve (b). 
chapter vi • Recommended Implementation Procedures 
