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Final 2020 Water Quality Assessment Guidance Manual

Virginia bases its water quality assessment on the ability of the waters to support the associated designated uses. Designated use support is established on the waters meeting the criteria for each use as defined in the numeric and/or narrative water quality standards. A description of these designated uses and the assessment indicators used to assess them is presented in the table.

DESIGNATED USE

USE DESCRIPTION/INDICATORS

Aquatic Life Use, Chesapeake Bay sub-uses

Description: The propagation, growth, and protection of a balanced indigenous population of aquatic life that may be expected to inhabit a waterbody

Indicators: Dissolved oxygen, pH, temperature, chlorophyll a*, nutrients*, water column and sediment toxics, toxicity tests, bottom-dwelling macroinvertebrates, submerged aquatic vegetation

Fish Consumption Use

Description: Game and marketable fish species that are safe for human health

Indicators: VDH notices, fish tissue toxics, water column toxics

Shellfishing Use

Description: Marketable shellfish (clams, oysters, mussels) that are safe for human health

Indicators: VDH notices

Recreation (Swimming) Use

Description: Swimming, boating, and other recreational activities

Indicators: VDH notices, bacteria

Public Water Supply Use

Description: Drinking water safe for human health

Indicators: VDH notices, water column toxics

Wildlife Use

Description: The propagation, growth, and protection of associated wildlife

Indicators: Water column toxics

*Chlorophyll a and nutrients (total phosphorus) are assessed only in the lakes listed in Section 187 of the WQS.  Chlorophyll a is also assessed in the tidal James River.

Virginia’s 2020 Water Quality Assessment Guidance Manual (11.7 MB Word doc) contains the assessment procedures and methods to be used for the development of Virginia’s 2020 §305(b)/§303(d) Integrated (i.e. combined Water Quality Assessment and Impaired Waters) Report. The assessment guidance seeks to address all key elements of the U.S. Environmental Protection Agency (EPA) 2006 Assessment Guidance and subsequent updates current to May 2019, in addition to the assessment methodology for Chesapeake Bay Water Quality Standards established by EPA and adopted by Virginia (Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity, and Chlorophyll a for the Chesapeake Bay and Its Tidal Tributaries).

Modifications have been made to the guidance document since 2018. A complete list of significant guidance modifications are described in Part II of the manual.

Section 62.1-44.19:5 C of the Code of Virginia requires DEQ to develop and publish the procedures used for defining and determining impaired waters and provide for public comment on the procedures. The public was invited to submit written comments on the draft Guidance from May 28 through June 27, 2019. DEQ responses to comments received are included in the response document.

Section 2.2-4002.1 of the Code of Virginia requires final guidance documents to be subject to a 30-day public comment period prior to becoming effective. The public comment period was from August 5 through September 4, 2019. No comments were received. The effective date for the 2020 IR Guidance is September 5, 2019. The final guidance document can be found on Town Hall here.

For additional information contact:

     Amanda Shaver
     Virginia Department of Environmental Quality
     Water Quality Assessment Coordinator
     P.O. Box 1105
     Richmond, Virginia 23218
     Telephone (804) 698-4181
     Fax (804) 698-4032

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Virginia Department of
Environmental Quality
P.O. Box 1105
Richmond, VA 23218
(804) 698-4000


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