Final Water Quality Assessment Guidance Manual

The 2008 federal assessment methodology guidance remains largely unchanged, as has state guidance, however there are changes to state guidance, outlined below, that reflect new and proposed Water Quality Standards which will be adopted by the release date of the assessment report in 2008, as well as changes to the methods of assessing Chesapeake Bay Water Quality Standards, consistent with “The Final Revised Draft 3/16/07 Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity, and Chlorophyll a for the Chesapeake Bay and Its Tidal Tributaries 2007 Addendum” by the U.S. Environmental Protection Agency.

Changes to the guidance affecting the assessment of the Chesapeake Bay and Its Tidal Tributaries:

• Revised Continuous Frequency Distribution (CFD) reference curves for 30-day dissolved oxygen criteria in both the Open Water and Deep Water designated sub-uses
• New CFD reference curve and procedure for instantaneous dissolved oxygen criteria in the Deep Channel designated sub-uses
• The following criteria will not be assessed for the 2008 assessment due to lack of fully developed methods and/or available data:
  • All 1-day and 7-day dissolved oxygen criteria
  • Instantaneous minimum dissolved oxygen criteria except in the Deep Channel designated sub-use
• Procedures for assessing the water clarity acres criteria have been established
• A method for assessing water clarity through a CFD method has been established
• Procedures for assessment of the numerical Chlorophyll a criteria in the James River have been established
• Special D.O. criteria adopted in 2006 for the Mattaponi and Pamunkey River will be used

 

Changes to the guidance affecting waters statewide:

• Nutrient standards for the assessment of lakes in place of previously used Trophic State Index (TSI)
• Continued use of the 10.5% Rule for dissolved oxygen (D.O.), pH, temperature and bacteria
• Use of the new Virginia Stream Condition Index for assessing macroinvertebrate health
• Final phase out and removal of the fecal coliform criteria
• Guidelines for the use of citizen benthic monitoring data for listing impaired waters
• Use of freshwater probabilistic monitoring data

A copy of the guidance can be downloaded at this link: Final 2008 WQA Guidance Manual (1.6 MB PDF)

A copy of the comment response can be downloaded at this link: 2008 Comment Response (309 kb PDF)

For a hard copy of the guidance or for more information, please contact Harry Augustine, DEQ Water Quality Assessment Coordinator, using the information below.

Contact:

Harry Augustine

Department of Environmental Quality
P.O. Box 1105
Richmond, Virginia 23218
Telephone (804) 698-4037
FAX (804) 698-4116

Click here for a copy of the Public Notice (63 kb PDF)