A-40 
In preparing water clarity CFDs for reference areas defined by having successful 
SAV beds, it is not unusual to find a curve shape similar to Figure 5.2 orange or 
yellow curves. This pattern suggests that SAV is tolerant of ephemeral events of 
spatially broad degraded water clarity. If water clarity is persistently degraded over 
portions of the area, SAV may be impaired. 
Example 3. Example 3 considers the effect of changing the spatial variance on the 
shape of the CFD. Again the population mean is held constant at 3 which corre¬ 
sponds to the curve 2 of the first example. 
Table 5.3. Parameter values and key for the family of curves shown in Figure 5.3 
n 
d s 
C 
color 
curve 
number 
3 
1 
1 
5 
Red 
1 
3 
2 
1 
5 
Orange 
2 
3 
3 
1 
5 
Brown 
3 
3 
4 
1 
5 
Green 
4 
3 
5 
1 
5 
Blue 
5 
Pmixrt-tion of S|>ar** 
Figure 5.3. A family of curves illustrating the behavior of the CFD as the spatial popula¬ 
tion variance increases. The parameter values for each curve and the corresponding curve 
number are given in Table 5.3. 
appendix a 
The Cumulative Frequency Diagram Method for Determining Water Quality Attainment 
