Title of Regulation: 9VAC25-260. Water Quality Standards (amending 9VAC25-260-185).

Statutory Authority: § 62.1-44.15 of the Code of Virginia; 33 USC § 1251 et seq. of the federal Clean Water Act; 40 CFR Part 131.

Public Hearing Information: No public hearings are scheduled.

Public Comment Deadline: December 22, 2010.

Effective Date: January 6, 2011.

Agency Contact: Alan Pollock, Department of Environmental Quality, 629 East Main Street, P.O. Box 1105, Richmond, VA 23218, telephone (804) 698-4002, FAX (804) 698-4116, or email alan.pollock@deq.virginia.gov.

Basis: Section 62.1-44.15 of the Code of Virginia mandates and authorizes the State Water Control Board to establish water quality standards and policies for any state waters consistent with the purpose and general policy of the State Water Control Law, and to modify, amend, or cancel any such standards or policies established. The federal Clean Water Act at § 303(c) mandates the State Water Control Board to review and, as appropriate, modify and adopt water quality standards. The promulgating entity is the State Water Control Board.

The corresponding federal water quality standards regulation at 40 CFR 131.6 describes the minimum requirements for water quality standards. The minimum requirements are use designations, water quality criteria to protect the designated uses, and an antidegradation policy. All of the citations mentioned describe mandates for water quality standards.

The U.S. Environmental Protection Agency (EPA) Water Quality Standards regulation (40 CFR 131.11) is the regulatory basis for the EPA requiring states to establish water quality criteria to protect designated uses and the criteria are used to assess whether a waterbody is meeting those uses.

Purpose: The proposed amendments to the regulation are essential to protect the health, safety, and welfare of the citizens of the Commonwealth by protecting the water quality and living resources of the Chesapeake Bay and its tidal rivers. EPA has continued to refine the assessment procedures as scientific research and management applications reveal new insights and knowledge about the Chesapeake Bay. The EPA's procedure documents being incorporated into Virginia regulation by this action replace or otherwise supersede similar criteria assessment procedures published in earlier documents, but not all of them. Therefore, it is necessary for the Virginia water quality standards to refer to each of the addenda published by EPA.

Rationale for Using Fast-Track Process: The proposed amendment to 9VAC25-260-185 B references assessment protocol documents published by EPA. These protocols have been developed by EPA through a collaborative process within the Chesapeake Bay Program. Other amendments are to correct reference to water quality standard sections, misspellings, and grammar and to add clarity. The proposed amendments are expected to be non-controversial and therefore justify using the fast track process.

Substance: The proposed substantive amendment to 9VAC25-260-185 B of the Water Quality Standards is a reference to the October 2007, September 2008, and May 2010 Chesapeake Bay Criteria Assessment Protocols Addenda. These recently published protocols are being used by EPA to develop the total maximum daily loads (TMDLs) for the Chesapeake Bay and its tidal rivers. TMDLs must be developed in accordance with approved water quality standards. Therefore, it is necessary for the Virginia water quality standards to refer to each of the addenda published by EPA.

Issues: There are no primary advantages or disadvantages to the public. The primary advantage to the agency and the Commonwealth is having improved methods for assessing attainment of designated uses in the Chesapeake Bay. There is no disadvantage to the agency or the Commonwealth that will result from the adoption of this amendment.

The Department of Planning and Budget's Economic Impact Analysis:

Summary of the Proposed Amendments to Regulation. The State Water Control Board (Board) proposes to incorporate the latest United States Environmental Protection Agency (EPA) Chesapeake Bay Criteria Assessment Protocols Addenda into these regulations.

Result of Analysis. The benefits likely exceed the costs for all proposed changes.

Estimated Economic Impact. In reference to whether various specified criteria for the protection of the Chesapeake Bay are met, the current and proposed regulations state that

Attainment of these criteria shall be assessed through comparison of the generated cumulative frequency distribution of the monitoring data to the applicable criteria reference curve for each designated use. If the monitoring data cumulative frequency curve is completely contained inside the reference curve, then the segment is in attainment of the designated use.

The regulations list the EPA documents that specify the reference curves and procedures to be followed. The Board proposes to add the October 2007, September 2008, and May 2010 Chesapeake Bay Criteria Assessment Protocols Addenda to the list of EPA documents that specify the reference curves and procedures to be followed.

In practice this will produce three changes. First, chlorophyll level data will be averaged with a geometric mean rather than an arithmetic mean. This will reduce the likelihood that a spike in the data will produce an average that is not reflective of the most common data readings. This will slightly reduce the chance that chlorophyll levels for a Chesapeake Bay segment will be deemed unacceptable due to a single outlier reading. Second, a different methodology that will more accurately reflect levels of dissolved oxygen will be used. Third, reference curves have been updated to reflect the best current available information. Neither the different methodology for measuring dissolved oxygen nor the updating of reference curves is expected to greatly affect the likelihood of whether a Chesapeake Bay segment will be deemed to be meeting water quality standards, but will be beneficial in that the accuracy of information produced for consideration will likely be moderately improved.

Businesses and Entities Affected. These regulations affect entities with point source permitted discharges greater than 0.5 million gallons per day (MGD) with nutrients and oxygen demanding substances in their discharge. This includes sewage treatment plants, food processing (poultry and seafood), chemical and pulp and paper industries.

Localities Particularly Affected. These regulations particularly affect localities containing or adjacent to the Chesapeake Bay, Potomac River, Rappahannock River, Corrotoman River, Piankatank River, Mattaponi River, Pamunkey River, York River, Mobjack Bay, James River, Appomattox River, Chickahominy River, Elizabeth River, Lafayette River, Lynnhaven River, Pocomoke River, and Tangier Sound.

Projected Impact on Employment. The proposal amendments are unlikely to significantly affect employment.

Effects on the Use and Value of Private Property. The proposed amendments are unlikely to significantly affect the use and value of private property.

Small Businesses: Costs and Other Effects. The proposed amendments are unlikely to significantly affect small businesses.

Small Businesses: Alternative Method that Minimizes Adverse Impact. The proposed amendments are unlikely to significantly affect small businesses.

Real Estate Development Costs. The proposed amendments are unlikely to significantly affect real estate development costs.

Legal Mandate. The Department of Planning and Budget (DPB) has analyzed the economic impact of this proposed regulation in accordance with § 2.2-4007.04 of the Administrative Process Act and Executive Order Number 14 (10). Section 2.2-4007.04 requires that such economic impact analyses include, but need not be limited to, the projected number of businesses or other entities to whom the regulation would apply, the identity of any localities and types of businesses or other entities particularly affected, the projected number of persons and employment positions to be affected, the projected costs to affected businesses or entities to implement or comply with the regulation, and the impact on the use and value of private property. Further, if the proposed regulation has adverse effect on small businesses, § 2.2-4007.04 requires that such economic impact analyses include (i) an identification and estimate of the number of small businesses subject to the regulation; (ii) the projected reporting, recordkeeping, and other administrative costs required for small businesses to comply with the regulation, including the type of professional skills necessary for preparing required reports and other documents; (iii) a statement of the probable effect of the regulation on affected small businesses; and (iv) a description of any less intrusive or less costly alternative methods of achieving the purpose of the regulation. The analysis presented above represents DPB's best estimate of these economic impacts.

Agency's Response to the Department of Planning and Budget's Economic Impact Analysis: The department has reviewed the economic impact analysis prepared by the Department of Planning and Budget and has no comment.

Summary:

The proposed amendment to the Chesapeake Bay nutrient criteria section (9VAC25-260-185) of the Water Quality Standards regulation incorporates the October 2007, September 2008, and May 2010 Chesapeake Bay Criteria Assessment Protocols Addenda. The amendment also corrects grammatical errors to footnote 1 of 9VAC25-260-185 B and in 9VAC25-260-185 D 1.

9VAC25-260-185. Criteria to protect designated uses from the impacts of nutrients and suspended sediment in the Chesapeake Bay and its tidal tributaries.

A. Dissolved oxygen.

Designated Use	Criteria Concentration/ Duration	Temporal Application
Migratory fish spawning and nursery	7-day mean ≥ 6 mg/l (tidal habitats with 0-0.5 ppt salinity)	February 1 - May 31
	Instantaneous minimum ≥ 5 mg/l
Open water1	30 day mean ≥ 5.5 mg/l (tidal habitats with 0-0.5 ppt salinity)	year-round2
	30 day mean ≥ 5 mg/l (tidal habitats with > 0.5 ppt salinity)
	7 day mean ≥ 4 mg/l
	Instantaneous minimum ≥ 3.2 mg/l at temperatures < 29°C Instantaneous minimum ≥ 4.3 mg/l at temperatures ≥ 29°C
Deep water	30 day mean ≥ 3 mg/l	June 1 - September 30
	1 day mean ≥ 2.3 mg/l
	Instantaneous minimum ≥ 1.7 mg/l
Deep channel	Instantaneous minimum ≥ 1 mg/l	June 1 - September 30
1In applying this open water instantaneous criterion to the Chesapeake Bay and its tidal tributaries where the existing water quality for dissolved oxygen exceeds an instantaneous minimum of 3.2 mg/l, that higher water quality for dissolved oxygen shall be provided antidegradation protection in accordance with 9 VAC 25-610-30 A 2 9VAC25-260-30 A 2. 2Open-water dissolved oxygen criteria attainment is assessed separately over two time periods: summer (June 1- September 30) and nonsummer (October 1-May 31) months.

B. Submerged aquatic vegetation and water clarity. Attainment of the shallow-water submerged aquatic vegetation designated use shall be determined using any one of the following criteria:

Designated Use	Chesapeake Bay Program Segment	SAV Acres1	Percent Light-Through-Water2	Water Clarity Acres1	Temporal Applica-tion
Shallow Water Submerged Aquatic Vegetation Use	CB5MH	7,633	22%	14,514	April 1 - October 31
	CB6PH	1,267	22%	3,168	March 1 - November 30
	CB7PH	15,107	22%	34,085	March 1 - November 30
	CB8PH	11	22%	28	March 1 - November 30
	POTTF	2,093	13%	5,233	April 1 - October 31
	POTOH	1,503	13%	3,758	April 1 - October 31
	POTMH	4,250	22%	10,625	April 1 - October 31
	RPPTF	66	13%	165	April 1 - October 31
	RPPOH	4	13%	10	April 1 - October 31
	RPPMH	1700	22%	5000	April 1 - October 31
	CRRMH	768	22%	1,920	April 1 - October 31
	PIAMH	3,479	22%	8,014	April 1 - October 31
	MPNTF	85	13%	213	April 1 - October 31
	MPNOH	-	-	-	-
	PMKTF	187	13%	468	April 1 - October 31
	PMKOH	-	-	-	-
	YRKMH	239	22%	598	April 1 - October 31
	YRKPH	2,793	22%	6,982	March 1 - November 30
	MOBPH	15,901	22%	33,990	March 1 - November 30
	JMSTF2	200	13%	500	April 1 - October 31
	JMSTF1	1000	13%	2500	April 1 - October 31
	APPTF	379	13%	948	April 1 - October 31
	JMSOH	15	13%	38	April 1 - October 31
	CHKOH	535	13%	1,338	April 1 - October 31
	JMSMH	200	22%	500	April 1 - October 31
	JMSPH	300	22%	750	March 1 - November 30
	WBEMH	-	-	-	-
	SBEMH	-	-	-	-
	EBEMH	-	-	-	-
	ELIPH	-	-	-	-
	LYNPH	107	22%	268	March 1 - November 30
	POCOH	-	-	-	-
	POCMH	4,066	22%	9,368	April 1 - October 31
	TANMH	13,579	22%	22,064	April 1 - October 31

¹The assessment period for SAV and water clarity acres shall be the single best year in the most recent three consecutive years. When three consecutive years of data are not available, a minimum of three years within the data assessment window shall be used.

²Percent Light through Water = 100e^(-KdZ) where K_d is water column light attenuation coefficient and can be measured directly or converted from a measured secchi depth where K_d = 1.45/secchi depth. Z = depth at location of measurement of K_d.

C. Chlorophyll a.

Designated Use	Chlorophyll a Narrative Criterion	Temporal Application
Open Water	Concentrations of chlorophyll a in free-floating microscopic aquatic plants (algae) shall not exceed levels that result in undesirable or nuisance aquatic plant life, or render tidal waters unsuitable for the propagation and growth of a balanced, indigenous population of aquatic life or otherwise result in ecologically undesirable water quality conditions such as reduced water clarity, low dissolved oxygen, food supply imbalances, proliferation of species deemed potentially harmful to aquatic life or humans or aesthetically objectionable conditions.	March 1 - September 30
*See 9VAC25-260-310 special standard bb for numerical chlorophyll criteria for the tidal James River.

D. Implementation.

1. Chesapeake Bay program segmentation scheme as described in Chesapeake Bay Program, 2004 Chesapeake Bay Program Analytical Segmentation Scheme-Revisions, Decisions and Rationales: 1983—2003, CBP/TRS 268/04, EPA 903-R-04-008, Chesapeake Bay Program, Annapolis, Maryland, and the Chesapeake Bay Program published 2005 addendum (CBP/TRS 278-06; EPA 903-R-05-004) is listed below and shall be used as the spatial assessment unit to determine attainment of the criteria in this section for each designated use.

Chesapeake Bay Segment Description	Segment Name1	Chesapeake Bay Segment Description	Segment Name1
Lower Central Chesapeake Bay	CB5MH	Mobjack Bay	MOBPH
Western Lower Chesapeake Bay	CB6PH	Upper Tidal Fresh James River	JMSTF2
Eastern Lower Chesapeake Bay	CB7PH	Lower Tidal Fresh James River	JMSTF1
Mouth of the Chesapeake Bay	CB8PH	Appomattox River	APPTF
Upper Potomac River	POTTF	Middle James River	JMSOH
Middle Potomac River	POTOH	Chickahominy River	CHKOH
Lower Potomac River	POTMH	Lower James River	JMSMH
Upper Rappahannock River	RPPTF	Mouth of the James River	JMSPH
Middle Rapphannock Rappahannock River	RPPOH	Western Branch Elizabeth River	WBEMH
Lower Rapphannock Rappahannock River	RPPMH	Southern Branch Elizabeth River	SBEMH
Corrotoman River	CRRMH	Eastern Branch Elizabeth River	EBEMH
Piankatank River	PIAMH	Lafayette River	LAFMH
Upper Mattaponi River	MPNTF	Mouth of the Elizabeth River	ELIPH
Lower Mattaponi River	MPNOH	Lynnhaven River	LYNPH
Upper Pamunkey River	PMKTF	Middle Pocomoke River	POCOH
Lower Pamunkey River	PMKOH	Lower Pocomoke River	POCMH
Middle York River	YRKMH	Tangier Sound	TANMH
Lower York River	YRKPH

¹First three letters of segment name represent Chesapeake Bay segment description, letters four and five represent the salinity regime of that segment (TF = Tidal Fresh, OH = Oligohaline, MH = Mesohaline and PH = Polyhaline) and a sixth space is reserved for subdivisions of that segment.

2. The assessment period shall be the most recent three consecutive years. When three consecutive years of data are not available, a minimum of three years within the the data assessment window shall be used.

3. Attainment of these criteria shall be assessed through comparison of the generated cumulative frequency distribution of the monitoring data to the applicable criteria reference curve for each designated use. If the monitoring data cumulative frequency curve is completely contained inside the reference curve, then the segment is in attainment of the designated use. The reference curves and procedures to be followed are published in the USEPA, Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a for the Chesapeake Bay and Its Tidal Tributaries, EPA 903-R-03-002, April 2003 and the 2004 (EPA 903-R-03-002 October 2004) and , 2007 (CBA/TRS (CBP/TRS 285-07, EPA 903-R-07-003), 2007 (CBP/TRS 288/07, EPA 903-R-07-005), 2008 (CBP/TRS 290-08, EPA 903-R-08-001), and 2010 (CBP/TRS 301-10, EPA 903-R-10-002) addenda. An exception to this requirement is in measuring attainment of the SAV and water clarity acres, which are compared directly to the criteria.

DOCUMENTS INCORPORATED BY REFERENCE (9VAC25-260)

Chesapeake Bay Program Analytical Segmentation Scheme -- Revisions, Decisions and Rationales 1983-2003, EPA 903-R-04-008, CBP/TRS 268/04, October 2004, US EPA Region III Chesapeake Bay Office.

Chesapeake Bay Program Analytical Segmentation Scheme -- Revisions, Decisions and Rationales 1983-2003, EPA 903-R-05-004, CBP/TRS 278-06, 2005 Addendum, December 2005, US EPA Region III Chesapeake Bay Office.

Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a for the Chesapeake Bay and Its Tidal Tributaries, EPA 903-R-03-002, April 2003 and 2004 Addendum, October 2004, US EPA Region III Chesapeake Bay Office

Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a for the Chesapeake Bay and Its Tidal Tributaries, EPA 903-R-07-003, CBP/TRS 285/07 2007 Addendum, July 2007, US EPA Region III Chesapeake Bay Office.

Technical Support Document for Identification of Chesapeake Bay Designated Uses and Attainability, EPA 903-R-03-004, October 2003 and 2004 Addendum, October 2004, US EPA Region III Chesapeake Bay Office.

Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a for the Chesapeake Bay and its Tidal Tributaries - 2007 Chlorophyll Criteria Addendum, EPA 903-R-07-005, CBP/TRS 288/07, November 2007, U.S. EPA Region III Chesapeake Bay Office.

Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a for the Chesapeake Bay and its Tidal Tributaries - 2008 Technical Support for Criteria Assessment Protocols Addendum, EPA 903-R-08-001, CBP/TRS 290-08, September 2008, U.S. EPA Region III Chesapeake Bay Office.

Ambient Water Quality Criteria for Dissolved Oxygen, Water Clarity and Chlorophyll a for the Chesapeake Bay and its Tidal Tributaries - 2010 Technical Support for Criteria Assessment Protocols Addendum, EPA 903-R-10-002, CBP/TRS 301-10, May 2010, U.S. EPA Region III Chesapeake Bay Office.