A-53 
Table 6-1. Evaluation of CFD approach as Best Science or Best Available Science accord¬ 
ing to AFS/ERF "Defining and Implementing Best Available Science for Fisheries 
and Environmental Science, Policy, and Management" (Sullivan et al. 2006). 
Attribute 
Best 
Science 
Best 
Available 
Science 
Current State of Development of CFD 
Approach 
Clear Objective 
YES 
YES 
Using biological response standards, combine 
available water quality in time and space to determine 
levels of attainment of Bay segments. 
Conceptual 
Model 
YES 
YES 
1. Bay divided into functional classifications - 
“Designated Uses.” 
2. Reference curves establish biologically 
relevant threshold levels for attainment. 
3. CFD combines and weights equally temporal 
and spatial sources of water quality 
variability. 
Experimental 
Design 
NO 
YES 
1. Bay segments are quasi-stratified for water 
quality data collection. 
2. Stratification of water quality data by 
designated units does not yet occur. 
3. Seasonal assessment of water quality 
attainment through spatial interpolation and 
the CFD approach is feasible but incompletely 
developed. 
Statistical Rigor 
NO 
YES 
1. Procedures for quantifying uncertainty 
associated with sampling design, spatial 
interpolation and CFD approach are feasible 
but incompletely developed. 
2. Procedures for interpolating water quality data 
are feasible but incompletely developed, 
particularly for 3-D interpolations of 
dissolved oxygen. 
3. Procedures for testing inferences related to the 
CFD curve are feasible but incompletely 
developed. 
Clear 
Documentation 
YES 
YES 
CFD approach, water quality sampling design, and 
current interpolation procedures well documented in 
Chesapeake Bay Program Reports and on website. 
Peer Review 
NO 
YES 
1. CFD approach and sampling design upon 
which it is based has not been peer-reviewed 
in the scientific literature. 
2. This report comprises the first external review 
by scientists with statistical expertise. 
3. Grey literature reports produced by CBP 
received expert and stakeholder input. 
appendix a 
The Cumulative Frequency Diagram Method for Determining Water Quality Attainment 
