4 
cha pter ii 
Refinements to the Chesapeake 
Bay Water Quality Criteria 
Assessment Methodology 
BACKGROUND 
The Chesapeake Bay water quality criteria were designed to protect the ecological 
integrity of the Bay’s tidal waters. To ensure that the criteria are being attained and 
the Chesapeake Bay ecosystem is, in fact, protected, adequate means to measure and 
evaluate water quality relative to the criteria must exist. The Bay is a highly diverse 
and variable system; these characteristics make precise assessment of water quality 
criteria attainment difficult. Thus, it is critical to design both a data collection system 
and a data analysis methodology carefully to make the best use of existing resources 
and provide the best possible assessment of water quality criteria attainment. Such a 
design can inform stakeholders about the status of impairments and whether the 
impairments have been removed once management actions have resulted in the 
achievement of the desired restoration goals. 
To address the need for enhanced water quality criteria assessments brought on by 
the states’ adoption of new Chesapeake Bay water quality standards, the Chesapeake 
Bay Program 1 redesigned its tidal monitoring network to provide a framework for 
interpreting the data. To the extent possible (within funding constraints), existing 
monitoring programs were either enhanced to support criteria assessment or new 
monitoring programs were established to address monitoring gaps. Given the diver¬ 
sity of tidal habitats throughout the Bay, establishing a comprehensive tidal 
monitoring network required different types of monitoring. 
'The Chesapeake Bay Program, formed in 1983 by the first Chesapeake Bay agreement, is a unique 
regional partnership guiding the restoration of the Chesapeake Bay and its tidal tributaries. On water 
quality issues, the Chesapeake Bay Program partners include Delaware, Maryland, New York. 
Pennsylvania, Virginia, West Virginia, the District of Columbia, the Chesapeake Bay Commission, the 
U.S. Environmental Protection Agency, over 20 other federal agencies, academic institutions, local gov¬ 
ernments, and citizen groups. 
chap-ter ii 
Refinements to the Chesapeake Bay Water Quality Criteria Assessment Methodology 
