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26. Assessment spreadsheets should be created for each season (i.e., spring 2004, 
2005, 2006 and summer 2004, 2005, 2006). Spreadsheets for spring chlorophyll 
estimates should have spring assessment criteria; likewise for “summer” spread¬ 
sheets. 
STEP 6. CREATING THE CFD 
27. The percent non-attainment for each assessed segment, at each season, should be 
copied and pasted into another spreadsheet. Organize them into columns corre¬ 
sponding to segment-season. For instance, label column 1 as “TF1 spring” and 
insert all the spring percent non-attainment values for TF1 into this column. In 
the next field insert all the spring percentages for “TF2 spring”. Continue doing 
this for all segment-season combinations. These columns correspond to the “% 
space” axis on the CFD. 
28. Sort them in descending order. 
29. To generate the “% time” axis, use the following equation: 
= (100* R)/ (N+l) 
where R = rank (“ 1 ” for the first time point, “2” for the second”, “3” for the third 
and “4” for the last). 
N = number of time points. Since the assessment period consists of three season- 
years, this number is equal to 3. 
30. For each % space column, insert 100% at the top of the column and 0% at the 
bottom. For the % time column, insert 0% at the top of the column and 100% at 
the bottom. 
31. You can now create the assessment curve. 
32. To calculate % space for the 10% reference curve, use the following equation: 
% space = [a/(y+b)] - b 
where y = % time 
b = 0.042995 
a = b 2 + b 
33. You can now create the 10% reference curve. 
STEP 7. CALCULATING THE PERCENT EXCESS NON-ATTAINMENT 
34. Convert the percentage axes of the CFD to fractional axes for this calculation. 
35. The trapezoidal rule should be applied to both assessment and reference curves 
to determine the area underneath each curve. The following website describes 
how to do the calculations using MS Excel: www.montanamath.org/ 
TMME/v4n 1 /TMMEv4n 1 a6.pdf 
36. Subtract the area under the assessment curve from the reference curve, looking 
only at the parts of the assessment curve that go beyond the reference curve. 
37. Multiply the value by 100. This number represents “% excess non-attainment”. 
appendix g 
Chlorophyll a Assessment Protocol 
