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ensure that the data are collected appropriately for use in interpolation and the 
overall CFD-based criteria assessment methodology. 
In addition to data collected by government and non-profit agencies, the states are 
also encouraged to work with agencies, organizations, or other entities subject to 
regulation, but with an interest in contributing data for use in the criteria attainment 
assessment process. Such agencies may be able to provide additional monitoring 
resources and significant amounts of supplementary data. Provided that an adequate 
QA/QC program is in place to ensure that the data are accurate, representative, and 
of known quality, these regulated agencies or entities may significantly benefit the 
criteria assessment process. 
The Hampton Roads Sanitation District in Virginia is one such example. The District 
has worked with the Virginia Department of Environmental Quality and the Virginia 
Institute of Marine Science to establish its own shallow-water monitoring program. 
The Virginia Department of Environmental Quality can use the data generated by the 
program to assess the state’s dissolved oxygen, water clarity, and chlorophyll a 
criteria in the lower tidal James River. Other similar organizations of regulated stake¬ 
holders may also wish to provide similar data. 
UPDATING THE CRITERIA ASSESSMENT FRAMEWORK 
The criteria assessment methodology developed for the Chesapeake Bay water 
quality criteria standards will require continued refinement into the future. The tech¬ 
nical details of the methodology continue to be refined through research and 
experience with application. This document describes many new refinements that 
will assist the jurisdictions with their criteria assessment process and listing deci¬ 
sions. More refinements are expected over the coming years. Furthermore, better 
understanding is developing with time as more data are collected. New monitoring 
programs (e.g., shallow-water monitoring) are offering new insight into the 
processes that affect water quality conditions in the Chesapeake Bay. This enhanced 
understanding will help fine-tune the requirements necessary for protection of the 
Bay ecosystem. Given that continued refinements of the criteria assessment method¬ 
ology are expected, it is recommended that the jurisdictions plan continued updates 
to their Chesapeake Bay water quality standards regulations through their existing 
triennial review process. The EPA commits to providing the information needed for 
updating the states' water quality standards through publication of recommended 
refinements to the criteria assessment procedures (such as in this addendum). The 
publication of any future addendums to the 2003 Chesapeake Bay criteria document 
will come in advance of the jurisdictions’ triennial reviews for use in justifying 
needed changes to the state’s water quality standards regulations. 
One example of the expected refinements to the criteria assessment methodology is 
the development of a statistical basis for decision-making using the CFD (see 
Chapter 2 and Appendices A and C for further details). Since the Chesapeake Bay 
criteria assessment methodology was first published in 2003, interest has grown in 
chapter iii 
Application of Chesapeake Bay Water Quality Criteria Assessment Procedures 
