9VAC25-260-10. Designation of uses.

A. All state waters, including wetlands, are designated for the following uses: recreational uses, e.g., swimming and boating; the propagation and growth of a balanced, indigenous population of aquatic life, including game fish, which might reasonably be expected to inhabit them; wildlife; and the production of edible and marketable natural resources, e.g., fish and shellfish.

B. Subcategories of the propagation and growth of a balanced indigenous population of aquatic life, including game fish designated use for waters in the Chesapeake Bay and its tidal tributaries are listed in this subsection.

1. Migratory Fish Spawning and Nursery Designated Use: waters in the Chesapeake Bay and its tidal tributaries that protect the survival, growth and propagation of the early life stages of a balanced, indigenous population of anadromous, semi-anadromous, catadromous and tidal-fresh resident fish species inhabiting spawning and nursery grounds. This designated use extends from the end of tidal waters to the downriver end of spawning and nursery habitats that have been determined through a composite of all targeted anadromous and semi-anadromous fish species' spawning and nursery habitats (see boundaries in U.S. Environmental Protection Agency, 2004, Technical Support Document for Identification of Chesapeake Bay Designated Uses and Attainability 2004 Addendum, Chesapeake Bay Program Office, Annapolis, Maryland). This designated use extends horizontally from the shoreline of the body of water to the adjacent shoreline, and extends down through the water column to the bottom water-sediment interface. This use applies February 1 through May 31 and applies in addition to the open-water use described in this subsection.

2. Shallow-water Submerged Aquatic Vegetation Designated Use: waters in the Chesapeake Bay and its tidal tributaries that support the survival, growth and propagation of submerged aquatic vegetation (rooted, underwater bay grasses). This use applies April 1 through October 31 in tidal-fresh, oligohaline and mesohaline Chesapeake Bay Program segments, and March 1 through November 30 in polyhaline Chesapeake Bay Program segments and applies in addition to the open-water use described in this subsection.

3. Open Water Aquatic Life Designated Use: waters in the Chesapeake Bay and its tidal tributaries that protect the survival, growth and propagation of a balanced, indigenous population of aquatic life inhabiting open-water habitats. This designated use applies year-round but the vertical boundaries change seasonally. October 1 through May 31, the open water aquatic life use extends horizontally from the shoreline at mean low water, to the adjacent shoreline, and extending through the water column to the bottom water-sediment interface. June 1 through September 30, if a pycnocline is present and, in combination with bottom bathymetry and water column circulation patterns, presents a barrier to oxygen replenishment of deeper waters, this designated use extends down into the water column only as far as the upper boundary of the pycnocline. June 1 through September 30, if a pycnocline is present but other physical circulation patterns (such as influx of oxygen rich oceanic bottom waters) provide for oxygen replenishment of deeper waters, the open-water aquatic life designated use extends down into the bottom water-sediment interface (see boundaries in U.S. Environmental Protection Agency, 2004 Technical Support Document for Identification of Chesapeake Bay Designated Uses and Attainability 2004 Addendum, Chesapeake Bay Program Office, Annapolis, Maryland). This designated use includes the migratory fish spawning and nursery and shallow-water submerged aquatic vegetation uses.

4. Deep Water Aquatic Life Designated Use: waters in the Chesapeake Bay and its tidal tributaries that protect the survival and growth of a balanced, indigenous population of aquatic life inhabiting deep-water habitats. This designated use extends to the tidally influenced waters located between the upper and lower boundaries of the pycnocline where, in combination with bottom bathymetry and water circulation patterns, a pycnocline is present and presents a barrier to oxygen replenishment of deeper waters. In some areas, the deep-water designated use extends from the upper boundary of the pycnocline down to the bottom water-sediment interface (see boundaries in U.S. Environmental Protection Agency, 2004 Technical Support Document for Identification of Chesapeake Bay Designated Uses and Attainability 2004 Addendum, Chesapeake Bay Program Office, Annapolis, Maryland). This use applies June 1 through September 30.

5. Deep Channel Seasonal Refuge Designated Use: waters in the Chesapeake Bay and its tidal tributaries that protect the survival of a balanced, indigenous population of benthic infauna and epifauna inhabiting deep-channel habitats. This designated use extends to the tidally influenced waters at depths greater than the lower boundary of the pycnocline in areas where, in combination with bottom bathymetry and water circulation patterns, the pycnocline presents a barrier to oxygen replenishment of deeper waters (see boundaries in U.S. Environmental Protection Agency, 2004 Technical Support Document for Identification of Chesapeake Bay Designated Uses and Attainability 2004 Addendum, Chesapeake Bay Program Office, Annapolis, Maryland). This use applies June 1 through September 30.

C. In designating uses of a water body and the appropriate criteria for those uses, the board shall take into consideration the water quality standards of downstream waters and shall ensure that its water quality standards provide for the attainment and maintenance of the water quality standards of downstream waters.

D. The board may adopt subcategories of a use and set the appropriate criteria to reflect varying needs of such subcategories of uses, for instance, to differentiate between cold water (trout streams) and warm water fisheries.

E. At a minimum, uses are deemed attainable if they can be achieved by the imposition of effluent limits required under §§ 301(b) §§ 301(b)(1)(A) and (B) and 306 of the Clean Water Act and cost-effective and reasonable best management practices for nonpoint source control.

F. Prior to adding or removing any use, or establishing subcategories of a use, the board shall provide notice and an opportunity for a public hearing under the Administrative Process Act (§ 2.2-4000 et seq. of the Code of Virginia).

G. The board may adopt seasonal uses as an alternative to reclassifying a water body or segment thereof to uses requiring less stringent water quality criteria. If seasonal uses are adopted, water quality criteria should be adjusted to reflect the seasonal uses; however, such criteria shall not preclude the attainment and maintenance of a more protective use in another season.

H. The board may remove a designated use which is not an existing use, or establish subcategories of a use, if the board can demonstrate that attaining the designated use is not feasible because:

1. Naturally occurring pollutant concentrations prevent the attainment of the use;

2. Natural, ephemeral, intermittent or low flow conditions or water levels prevent the attainment of the use unless these conditions may be compensated for by the discharge of sufficient volume of effluent discharges without violating state water conservation requirements to enable uses to be met;

3. Human caused conditions or sources of pollution prevent the attainment of the use and cannot be remedied or would cause more environmental damage to correct than to leave in place;

4. Dams, diversions or other types of hydrologic modifications preclude the attainment of the use, and it is not feasible to restore the water body to its original condition or to operate such modification in a way that would result in the attainment of the use;

5. Physical conditions related to the natural features of the water body, such as the lack of a proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water quality, preclude attainment of aquatic life protection uses; or

6. Controls more stringent than those required by §§ 301(b) and 306 of the Clean Water Act would result in substantial and widespread economic and social impact.

I. The board may not remove designated uses if:

1. They are existing uses, unless a use requiring more stringent criteria is added; or

2. Such uses will be attained by implementing effluent limits required under §§ 301(b) §§ 301(b)(1)(A) and (B) and 306 of the Clean Water Act and by implementing cost-effective and reasonable best management practices for nonpoint source control.

J. Where existing water quality standards specify designated uses less than those which are presently being attained, the board shall revise its standards to reflect the uses actually being attained.

K. The board must conduct a use attainability analysis whenever:

1. The board designates or has designated uses that do not include the uses specified in § 101(a)(2) of the Clean Water Act; or

2. The board wishes to remove a designated use that is specified in § 101(a)(2) of the Clean Water Act or to adopt subcategories of uses specified in § 101(a)(2) of the Clean Water Act which require less stringent criteria.

L. The board is not required to conduct a use attainability analysis under this chapter whenever designating uses which include those specified in subsection A of this section.

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.

Historical Notes

Derived from VR680-21-01.1, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Volume 20, Issue 9, eff. February 12, 2004; Volume 21, Issue 23, eff. June 24, 2005.

9VAC25-260-20. General criteria.

A. State waters, including wetlands, shall be free from substances attributable to sewage, industrial waste, or other waste in concentrations, amounts, or combinations which contravene established standards or interfere directly or indirectly with designated uses of such water or which are inimical or harmful to human, animal, plant, or aquatic life.

Specific substances to be controlled include, but are not limited to: floating debris, oil, scum, and other floating materials; toxic substances (including those which bioaccumulate); substances that produce color, tastes, turbidity, odors, or settle to form sludge deposits; and substances which nourish undesirable or nuisance aquatic plant life. Effluents which tend to raise the temperature of the receiving water will also be controlled. Conditions within mixing zones established according to 9VAC25-260-20 B do not violate the provisions of this subsection.

B. The board may use mixing zone concepts in evaluating limitations for Virginia Pollutant Discharge Elimination System permits.

1. Mixing zones evaluated or established by the board in fresh water shall not:

a. Prevent movement of or cause lethality to passing and drifting aquatic organisms through the water body in question;

b. Constitute more than one half of the width of the receiving watercourse nor constitute more than one third of the area of any cross section of the receiving watercourse;

c. Extend downstream at any time a distance more than five times the width of the receiving watercourse at the point of discharge.

2. Mixing zones evaluated or established by the board in open ocean, estuarine and transition zone waters (see 9VAC25-260-140 C) shall not:

a. Prevent movement of or cause lethality to passing and drifting aquatic organisms through the water body in question;

b. Extend more than five times in any direction the average depth along a line extending 1/3 of the way across the receiving water from the discharge point to the opposite shore.

3. A subsurface diffuser shall be required for any new or expanded freshwater discharge greater than or equal to 0.5 MGD to open ocean, estuarine and transition zone waters (see 9VAC25-260-140 C) and the acute and chronic criteria shall be met at the edge of the zone of initial mixing. The zone of initial mixing is the area where mixing of ambient water and effluent is driven by the jet effect and/or momentum of the effluent. Beyond this zone the mixing is driven by ambient turbulence.

4. Mixing zones shall not be allowed by the board for effluents discharged to wetlands, swamps, marshes, lakes or ponds.

5. An allocated impact zone may be allowed within a mixing zone. This zone is the area of initial dilution of the effluent with the receiving water where the concentration of the effluent will be its greatest in the water column. Mixing within these allocated impact zones shall be as quick as practical and shall be sized to prevent lethality to passing and drifting aquatic organisms. The acute aquatic life criteria are not required to be attained in the allocated impact zone.

6. Mixing zones shall be evaluated or established such that acute criteria are met outside the allocated impact zone and chronic criteria are met at the edge of the mixing zone.

7. No mixing zone shall be used for, or considered as, a substitute for minimum treatment technology required by the Clean Water Act and other applicable state and federal laws.

8. The board shall not approve a mixing zone that violates the federal Endangered Species Act of 1973 (16 USCA §§ 1531-1543) or the Virginia Endangered Species Act, Article 6 (§ 29.1-563 et seq.) of Chapter 5 of Title 29.1 of the Code of Virginia.

9. Mixing zones shall not be allowed for the bacteria criteria in 9VAC25-260-170.

10. The board may waive the requirements of subdivisions B 1 b and c, B 2 b, B 3 and B 4 of this subsection on a case-by-case basis if:

a. The board determines that a complete mix assumption is appropriate; or

b. A discharger provides an acceptable demonstration of:

(1) Information defining the actual boundaries of the mixing zone in question; and

(2) Information and data demonstrating no violation of subdivisions B 1 a, 2 a and B 7 of this subsection by the mixing zone in question.

10. 11. The size of a thermal mixing zone shall be determined on a case-by-case basis. This determination shall be based upon a sound rationale and be supported by substantial biological, chemical, physical, and engineering evidence and analysis. Any such determination shall show to the board's satisfaction that no adverse changes in the protection and propagation of balanced indigenous populations of fish, aquatic life, and wildlife may reasonably be expected to occur. A satisfactory showing made in conformance with § 316(a) of the Clean Water Act shall be deemed as compliance with the requirements of this section.

11. 12. Notwithstanding the above, no new or expanded mixing zone shall:

a. Be allowed in waters listed in 9VAC25-260-30 A 3 c;

b. Be allowed in waters defined in 9VAC25-260-30 A 2 for new or increased existing discharges unless the requirements outlined in 9VAC25-260-30 A 2 are satisfied.

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.

Historical Notes

Derived from VR680-21-01.2, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Errata, 14:12 VA.R. 1937 March 2, 1998; amended, Virginia Register Volume 20, Issue 9, eff. February 12, 2004.

9VAC25-260-30. Antidegradation policy.

A. All surface waters of the Commonwealth shall be provided one of the following three levels, or tiers, of antidegradation protection. This antidegradation policy shall be applied whenever any activity is proposed that has the potential to affect existing surface water quality.

1. As a minimum, existing instream water uses and the level of water quality necessary to protect the existing uses shall be maintained and protected.

2. Where the quality of the waters exceed water quality standards, that quality shall be maintained and protected unless the board finds, after full satisfaction of the intergovernmental coordination and public participation provisions of the Commonwealth's continuing planning process, that allowing lower water quality is necessary to accommodate important economic or social development in the area in which the waters are located. In allowing such degradation or lower water quality, the board shall assure water quality adequate to protect existing uses fully. Further, the board shall assure that there shall be achieved the highest statutory and regulatory requirements applicable to all new or existing point source discharges of effluent and all cost-effective and reasonable best management practices for nonpoint source control.

3. Surface waters, or portions of these, which provide exceptional environmental settings and exceptional aquatic communities or exceptional recreational opportunities may be designated and protected as described in subdivisions 3 a, b and c of this subsection.

a. Designation procedures.

(1) Designations shall be adopted in accordance with the provisions of the Administrative Process Act (§ 2.2-4000 et seq. of the Code of Virginia) and the board's public participation guidelines.

(2) Upon receiving a nomination of a waterway or segment of a waterway for designation as an exceptional state water pursuant to the board's antidegradation policy, as required by 40 CFR 131.12, the board shall notify each locality in which the waterway or segment lies and shall make a good faith effort to provide notice to impacted riparian property owners. The written notice shall include, at a minimum: (i) a description of the location of the waterway or segment; (ii) the procedures and criteria for designation as well as the impact of the designation; (iii) the name of the person making the nomination; and (iv) the name of a contact person at the Department of Environmental Quality who is knowledgeable about the nomination and the waterway or segment. Notice to property owners shall be based on names and addresses taken from local tax rolls. Such names and addresses shall be provided by the Commissioners of the Revenue or the tax assessor's office of the affected jurisdiction upon request by the board. After receipt of the notice of the nomination, localities shall be provided 60 days to comment on the consistency of the nomination with the locality's comprehensive plan. The comment period established by subdivision 3 a (2) of this subsection shall in no way impact a locality's ability to comment during any additional comment periods established by the board.

b. Implementation procedures.

(1) The quality of waters designated in subdivision 3 c of this subsection shall be maintained and protected to prevent permanent or long-term degradation or impairment.

(2) No new, additional, or increased discharge of sewage, industrial wastes or other pollution into waters designated in subdivision 3 c of this subsection shall be allowed.

(3) Activities causing temporary sources of pollution may be allowed in waters designated in subdivision 3 c of this subsection even if degradation may be expected to temporarily occur provided that after a minimal period of time the waters are returned or restored to conditions equal to or better than those existing just prior to the temporary source of pollution.

c. Surface waters designated under this subdivision are as follows:

(1) Little Stony Creek in Giles County from the first footbridge above the Cascades picnic area, upstream to the 3,300-foot elevation.

(2) Bottom Creek in Montgomery County and Roanoke County from Route 669 (Patterson Drive) downstream to the last property boundary of the Nature Conservancy on the southern side of the creek.

(3) Lake Drummond, located on U.S. Fish and Wildlife Service property, is nominated in its entirety within the cities of Chesapeake and Suffolk excluding any ditches and/or tributaries.

(4) North Creek in Botetourt County from the first bridge above the United States Forest Service North Creek Camping Area to its headwaters.

(5) Brown Mountain Creek, located on U.S. Forest Service land in Amherst County, from the City of Lynchburg property boundary upstream to the first crossing with the national forest property boundary.

(6) Laurel Fork, located on U.S. Forest Service land in Highland County, from the national forest property boundary below Route 642 downstream to the Virginia/West Virginia state line.

(7) North Fork of the Buffalo River, located on U.S. Forest Service land in Amherst County, from its confluence with Rocky Branch upstream to its headwaters.

(8) Pedlar River, located on U.S. Forest Service land in Amherst County, from where the river crosses FR 39 upstream to the first crossing with the national forest property boundary.

(9) Ramseys Draft, located on U.S. Forest Service land in Augusta County, from its headwaters (which includes Right and Left Prong Ramseys Draft) downstream to the Wilderness Area boundary.

(10) Whitetop Laurel Creek, located on U.S. Forest Service land in Washington County, from the national forest boundary immediately upstream from the second railroad trestle crossing the creek above Taylors Valley upstream to the confluence of Green Cove Creek.

(11) Ragged Island Creek in Isle of Wight County from its confluence with the James River at a line drawn across the creek mouth at N36°56.306'/W76°29.136' to N36°55.469'/W76°29.802' upstream to a line drawn across the main stem of the creek at N36°57.094'/W76°30.473' to N36°57.113'/W76°30.434', excluding wetlands and impounded areas and including only those tributaries completely contained within the Ragged Island Creek Wildlife Management Area on the northeastern side of the creek.

(12) Big Run in Rockingham County from its headwaters downstream to the first crossing with the Shenandoah National Park boundary and all tributaries to this segment of Big Run within the confines of Shenandoah National Park.

(13) Doyles River in Albemarle County from its headwaters to the first crossing with the Shenandoah National Park boundary and Jones Falls Run from its headwaters to its confluence with Doyles River and all tributaries to these segments of Doyles River and Jones Fall Run within the confines of Shenandoah National Park.

(14) East Hawksbill Creek in Page County from its headwaters downstream to the first crossing with the Shenandoah National Park boundary and all tributaries to this segment of East Hawksbill Creek within the confines of Shenandoah National Park.

(15) Jeremys Run in Page County from its headwaters downstream to the first crossing with the Shenandoah National Park boundary and all tributaries to this segment of Jeremys Run within the confines of Shenandoah National Park.

(16) East Branch Naked Creek in Page County from its headwaters downstream to the first crossing with the Shenandoah National Park boundary and all tributaries to this segment of East Branch Naked Creek within the confines of Shenandoah National Park.

(17) Piney River in Rappahannock County from its headwaters downstream to the first crossing with the Shenandoah National Park boundary and all tributaries to this segment of the Piney River within the confines of Shenandoah National Park.

(18) North Fork Thornton River in Rappahannock County from its headwaters downstream to the first crossing with the Shenandoah National Park boundary and all tributaries to this segment of the North Fork Thornton River within the confines of Shenandoah National Park.

(19) Blue Suck Branch from its headwaters downstream to the first crossing with the George Washington National Forest boundary.

(20) Downy Branch from its headwaters downstream to the first crossing with the George Washington National Forest boundary.

(21) North Branch Simpson Creek (Brushy Run) from its headwaters downstream to its confluence with Simpson Creek.

(22) Roberts Creek from its confluence with the Pedlar River upstream to its first crossing with the National Forest boundary.

(23) Shady Mountain Creek from its headwaters downstream to its confluence with the Pedlar River.

(24) Cove Creek from its headwaters downstream to the National Forest boundary.

(25) Little Cove Creek and its tributaries from the headwaters downstream to the National Forest boundary.

(26) Rocky Branch from its headwaters downstream to its confluence with the North Fork of the Buffalo River.

(27) North Fork of the Buffalo River from its confluence with Rocky Branch downstream to the National Forest Boundary.

(28) The Hazel River in Rappahannock County from its headwaters to the first downstream crossing with the Shenandoah National Park boundary and all tributaries within this segment within the confines of Shenandoah National Park.

(29) Little Stony Creek in Scott County from Bark Camp Lake dam to its confluence with Bakers Branch.

(30) North River in Augusta County from the Staunton Reservoir dam to the first crossing with National Forest lands boundary (near Girl Scout Camp May Flather).

B. Any determinations concerning thermal discharge limitations made under § 316(a) of the Clean Water Act will be considered to be in compliance with the antidegradation policy.

Statutory Authority

§ 62.1-44.15 of the Code of Virginia; Clean Water Act (33 USC § 1251 et seq.); 40 CFR Part 131.

Historical Notes

Derived from VR680-21-01.3, eff. May 20, 1992; amended, Virginia Register Volume 13, Issue 11, eff. March 19, 1997; Volume 13, Issue 14, eff. April 30, 1997; Volume 14, Issue 4, eff. December 10, 1997; Volume 14, Issue 9, eff. February 18, 1998; Volume 20, Issue 9, eff. February 12, 2004; Volume 21, Issue 22, eff. August 10, 2005; Volume 22, Issue 10, eff. December 29, 2005; Volume 24, Issue 2, eff. September 11, 2007; Volume 24, Issue 26, eff. August 12, 2008; Volume 25, Issue 5, eff. October 22, 2008; Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-50. Numerical criteria for dissolved oxygen, pH, and maximum temperature.***

*This classification recognizes that the natural quality of these waters may fall fluctuate outside of the ranges values for D.O. and pH set forth above as water quality criteria; therefore, on a case-by-case basis, in Class I through VI waters. The natural quality of these waters is the water quality found or expected in the absence of human-induced pollution. Water quality standards will not be considered violated when conditions are determined by the board to be natural and not due to human-induced sources. The board may develop site specific criteria for specific Class VII waters can be developed that reflect the natural quality of the waterbody when the evidence is sufficient to demonstrate that the site specific criteria rather than narrative criterion will fully protect aquatic life uses. Virginia Pollutant Discharge Elimination System limitations in Class VII waters shall meet pH of 6.0 - 9.0 not cause significant changes to the naturally occurring dissolved oxygen and pH fluctuations in these waters.

**Maximum temperature will be the same as that for Classes I through VI waters as appropriate.

***The water quality criteria in this section do not apply below the lowest flow averaged (arithmetic mean) over a period of seven consecutive days that can be statistically expected to occur once every 10 climatic years (a climatic year begins April 1 and ends March 31). See 9VAC25-260-310 and 9VAC25-260-380 through 9VAC25-260-540 for site specific adjustments to these criteria.

****See 9VAC25-260-55 for implementation of these criteria in waters naturally low in dissolved oxygen.

[  *****For ****For ] a thermally stratified man-made lake or reservoir in Class III, IV, V or VI waters that are listed in 9VAC25-260-187, these dissolved oxygen criteria apply only to the epilimnion [ in the lacustrine portion ] of the water body. When these waters are not stratified, the dissolved oxygen criteria apply throughout the water column.

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from VR680-21-01.5, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Volume 17, Issue 16 and Volume 18, Issue 17, eff. June 5, 2002; Volume 20, Issue 9, eff. February 12, 2004; Volume 21, Issue 23, eff. June 24, 2005; Volume 23, Issue 26, eff. August 14, 2007; Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-55. Implementation procedure for dissolved oxygen criteria in waters naturally low in dissolved oxygen. (Repealed.)

A. The board shall implement this procedure when assessing dissolved oxygen data in preparation of Clean Water Act §§ 305(b) and 303(d) reports in accordance with § 62.1-44.19:5 of the Water Quality Monitoring Information and Restoration Act. The board recognizes that dissolved oxygen concentrations may seasonally fall below the criteria established in 9VAC25-260-50 due to nonanthropogenic sources and physical and chemical processes resulting from:

1. Density stratification and depth in Class II waters that prevent mixing and reaeration of the deep waters;

2. Temperature stratification and depth in lakes and reservoirs in Class III, IV, V and VI waters that prevent mixing and reaeration of the deep waters; or

3. Minimal flow velocity and decomposition of vegetation that prevent mixing and reaeration of stagnant, shallow waters.

B. In preparation of the Clean Water Act §§ 305(b) and 303(d) reports, the board shall list waters as naturally impaired in accordance with § 62.1-44.19:5 C of the Code of Virginia when the board determines that the low dissolved oxygen concentrations result from nonanthropogenic sources and the physical and chemical processes described in subsection A of this section. The board shall make this determination based upon an evaluation of aquatic life, habitat (including anadromous fish spawning areas), monitoring data, computer modeling results or other accepted scientific principles. The board shall also conduct a watershed assessment to document anthropogenic sources that individually or cumulatively cause low dissolved oxygen concentrations including locating and identifying all point and nonpoint sources of pollution and identifying any man-made activities (such as water withdrawals) that cause low flow conditions and result in low dissolved oxygen levels.

C. The proposed determinations in subsection B of this section shall be subject to public comment on draft § 303(d) reports.

D. The final determinations in subsection B of this section shall be made available to the public in final § 303(d) reports.

E. Following a determination made under subsection B of this section, the board shall initiate a rulemaking to set site-specific criteria that reflect the natural quality of that water body or segment.

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from Virginia Register Volume 17, Issue 16 and Volume 18, Issue 17, eff. June 5, 2002; repealed, Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-90. Site-specific temperature requirements Thermal variances.

A. The temperature limits set forth in 9VAC25-260-50 through 9VAC25-260-80 may be superseded in certain locations by Site-Specific Temperature Criteria or in the case where a thermal variance demonstration is performed in accordance with § 316(a) of the Clean Water Act. The protocol for development of site-specific temperature requirements is found in subsection A of this section. Information regarding § 316(a) demonstrations is found in subsection B of this section.

B. Protocol for Developing Site-Specific Temperature Criteria. For any specified time of year there shall be two upper limiting temperatures for a location based on temperature requirements of important sensitive species found at the location at that time. These limiting temperatures are:

1. A maximum weekly average temperature that:

a. In the warmer months is determined by adding to the physiological optimum temperature (usually the optimum for growth) for the most sensitive important species (and appropriate life stage) that normally is found at that location and time; a factor calculated as one third of the difference between the ultimate upper incipient lethal temperature and the optimum temperature for that species;

b. In the cooler months is an elevated temperature that would still ensure that important species would survive if the temperature suddenly dropped to the normal ambient temperature;

c. During reproduction seasons meets specific site requirements for successful migration, spawning, egg incubation, fry rearing, and other reproductive functions of important species; and

d. At a specific site is found necessary to preserve normal species diversity or prevent undesirable growths of nuisance organisms.

2. A time-dependent maximum temperature for short exposures.

Baseline thermal conditions shall be measured at a site where there is no unnatural thermal addition from any source, which site is in reasonable proximity to the thermal discharge (within five miles), and which has similar hydrography to that of the receiving waters at the point of discharge.

Criteria development should be in accordance with Water Quality Criteria 1972: A Report of the Committee on Water Quality Criteria and Quality Criteria for Water, U.S. Environmental Protection Agency.

C. § 316(a) Determinations. A successful demonstration accepted by the board concerning thermal discharge limits carried out under § 316(a) of the Clean Water Act shall constitute compliance with the temperature requirements of these standards. A successful demonstration must assure the protection and propagation of a balanced indigenous population of aquatic species and wildlife in or on the water into which the discharge is made. When making a determination concerning thermal discharge limits under § 316(a) of the Clean Water Act, the board shall provide notice and opportunity for a public hearing.

Statutory Authority

§ 62.1-44.15(3a) of the Code of Virginia.

Historical Notes

Derived from VR680-21-01.9, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-140. Criteria for surface water.

A. Instream water quality conditions shall not be acutely² acutely¹ or chronically³ chronically² toxic except as allowed in 9VAC25-260-20 B (mixing zones). The following are definitions of acute and chronic toxicity conditions:

"Acute toxicity" means an adverse effect that usually occurs shortly after exposure to a pollutant. Lethality to an organism is the usual measure of acute toxicity. Where death is not easily detected, immobilization is considered equivalent to death.

"Chronic toxicity" means an adverse effect that is irreversible or progressive or occurs because the rate of injury is greater than the rate of repair during prolonged exposure to a pollutant. This includes low level, long-term effects such as reduction in growth or reproduction.

B. The following table is a list of numerical water quality criteria for specific parameters.

When information has become available from the Environmental Protection Agency to calculate additional aquatic life or human health criteria not contained in the table, the board may employ these values in establishing effluent limitations or other limitations pursuant to 9VAC25-260-20 A necessary to protect designated uses until the board has completed the regulatory standards adoption process.

Table of Parameters ^{6, 7}

¹One hour average concentration not to be exceeded more than once every 3 years on the average, unless otherwise noted.

²Four-day average concentration not to be exceeded more than once every 3 years on the average, unless otherwise noted.

³Criteria have been calculated to protect human health from toxic effects through drinking water and fish consumption, unless otherwise noted and apply in segments designated as PWS in 9VAC25-260-390-540.

⁴Criteria have been calculated to protect human health from toxic effects through fish consumption, unless otherwise noted and apply in all other surface waters not designated as PWS in 9VAC25-260-390-540.

⁵Acute and chronic saltwater and freshwater aquatic life criteria apply to the biologically available form of the metal and apply as a function of the pollutant's water effect ratio (WER) as defined in 9VAC25-260-140 F (WER X criterion). Metals measured as dissolved shall be considered to be biologically available, or, because local receiving water characteristics may otherwise affect the biological availability of the metal, the biologically available equivalent measurement of the metal can be further defined by determining a Water Effect Ratio (WER) and multiplying the numerical value shown in 9VAC25-260-140 B by the WER. Refer to 9VAC25-260-140 F. Values displayed above in the table are examples and correspond to a WER of 1.0. Metals criteria have been adjusted to convert the total recoverable fraction to dissolved fraction using a conversion factor. Criteria that change with hardness have the conversion factor listed in the table above.

⁶ = The flows listed below are default design flows for calculating steady state waste load allocations unless statistically valid methods are employed which demonstrate compliance with the duration and return frequency of the water quality criteria.

Aquatic Life:

Human Health:

The following are defined for this section:

"1Q10" means the lowest flow averaged over a period of one day which on a statistical basis can be expected to occur once every 10 climatic years.

"7Q10" means the lowest flow averaged over a period of seven consecutive days that can be statistically expected to occur once every 10 climatic years.

"30Q5" means the lowest flow averaged over a period of 30 consecutive days that can be statistically expected to occur once every five climatic years.

"30Q10" means the lowest flow averaged over a period of 30 consecutive days that can be statistically expected to occur once every 10 climatic years.

"Averaged" means an arithmetic mean.

"Climatic year" means a year beginning on April 1 and ending on March 31.

⁷The criteria listed in this table are two significant digits. For other criteria that are referenced to other sections of this regulation in this table, all numbers listed as criteria values are significant.

[ ⁸The fish tissue criterion for methylmercury applies to a concentration of 0.30 mg/kg as wet weight in edible tissue for species of fish and/or shellfish resident in a waterbody that are commonly eaten in the area and have commercial, recreational, or subsistence value. ]

C. Application of freshwater and saltwater numerical criteria. The numerical water quality criteria listed in subsection B of this section (excluding dissolved oxygen, pH, temperature) shall be applied according to the following classes of waters (see 9VAC25-260-50) and boundary designations:

The following described describes the boundary designations for Class II, (estuarine, transition zone and tidal freshwater waters) by river basin:

1. Rappahannock Basin. Tidal freshwater is from the fall line of the Rappahannock River to Buoy 37 near Tappahannock, Virginia, the upstream boundary of the transition zone including all tidal tributaries that enter the tidal freshwater Rappahannock River.

Transition zone is from Buoy 37 to Buoy 11 near Morattico, Virginia, including all tidal tributaries that enter the transition zone of the Rappahannock River.

Transition zone upstream boundary – 38° 4' 56.59"/-76° 58' 47.93" (430 feet east of Hutchinson Swamp) to 38° 5' 23.33"/-76° 58' 24.39" (0.7 miles upstream of Peedee Creek).

Transition zone downstream boundary - 37° 58' 45.80"/-76° 55' 28.75" (1,000 feet downstream of Jenkins Landing) to 37° 59' 20.07/ -76° 53' 45.09" (0.33 miles upstream of Mulberry Point). All tidal waters that enter the transition zone are themselves transition zone waters.

Estuarine waters are from Buoy 11 the downstream boundary of the transition zone to the mouth of the Rappahannock River (Buoy 6), including all tidal tributaries that enter the estuarine waters of the Rappahannock River.

2. York Basin. Tidal freshwater is from the fall line of the Mattaponi River at N37° 47' 20.03"/W77° 6' 15.16" (800 feet upstream of the Route 360 bridge in Aylett) to Clifton, Virginia the upstream boundary of the Mattaponi River transition zone, and from the fall line of the Pamunkey River at N37° 41' 22.64" /W77° 12' 50.83" (2,000 feet upstream of Totopotomy Creek) to Sweet Hall Landing, Virginia the upstream boundary of the Pamunkey River transition zone, including all tidal tributaries that enter the tidal freshwaters of the Mattaponi and Pamunkey Rivers.

Transition Mattaponni River transition zone upstream boundary of the Mattaponi River is from Clifton, Virginia to the York River and the transition zone of the Pamunkey River is from Sweet Hall Landing, Virginia, to the York River – N37° 39' 29.65"/W76° 52' 53.29" (1,000 feet upstream of Mitchell Hill Creek) to N37° 39' 24.20"/W76° 52' 55.87" (across from Courthouse Landing). Mattaponi River transition zone downstream boundary – N37° 32' 19.76"/W76° 47' 29.41" (old Lord Delaware Bridge, west side) to N37° 32' 13.25"/W76° 47' 10.30" (old Lord Delaware Bridge, east side).

Pamunkey River transition zone upstream boundary – N37° 32' 36.63"/W76° 58' 29.88" (Cohoke Marsh, 0.9 miles upstream of Turkey Creek) to N37° 32' 36.51"/W76° 58' 36.48" (0.75 miles upstream of creek at Cook Landing). Pamunkey River transition zone downstream boundary – N37° 31' 57.90"/ 76° 48' 38.22" (old Eltham Bridge, west side) to N37° 32' 6.25"/W76° [ 14' 48' ] 18.82" (old Eltham Bridge, east side).

The transition zone for the York River is from West Point, Virginia, to Buoy 13 near Poropotank Bay. All tidal tributaries that enter the transition zones of the Mattaponi, and Pamunkey, and York Rivers are themselves in the transition zone.

Estuarine waters are from Buoy 13 the downstream boundary of the transition zones of the Mattaponi and Pamunkey Rivers to the mouth of the York River (Tue Marsh Light) including all tidal tributaries that enter the estuarine waters of the York River.

3. James Basin. Tidal Freshwater is from the fall line of the James River in the City of Richmond upstream of Mayo Bridge to the confluence of the Chickahominy River (Buoy 70) upstream boundary of the transition zone, including all tidal tributaries that enter the tidal freshwater James River.

Transition James River transition zone is from Buoy 70 to Buoy 47 near Jamestown Island including all tidal tributaries that enter the transition zone of the James River upstream boundary – N37° 14' 28.25"/W76° 56' 44.47" (at Tettington) to N37° 13' 38.56"/W76° 56' 47.13" 0.3 miles downstream of Sloop Point.

Chickahominy River transition zone upstream boundary – N37° 25' 44.79"/W77° 1' 41.76" (Holly Landing).

Transition zone downstream boundary – N37° 12' 7.23/W76° 37' 34.70" (near Carters Grove Home, 1.25 downstream of Grove Creek) to N37° 9' 17.23/W76° 40' 13.45" (0.7 miles upstream of Hunnicutt Creek). All tidal waters that enter the transition zone are themselves transition zone waters.

Estuarine waters are from Buoy 47 the downstream transition zone boundary to the mouth of the James River (Buoy 25) including all tidal tributaries that enter the estuarine waters of the James River.

4. Potomac Basin. Tidal Freshwater includes all tidal tributaries that enter the Potomac River from its fall line at the Chain Bridge (N38° 55' 46.28"/W77° 6' 59.23") to Buoy 43 the upstream transition zone boundary near Quantico, Virginia.

Transition zone includes all tidal tributaries that enter the Potomac River from Buoy 43 N38° 31' 27.05"/W77° 17' 7.06" (midway between Shipping Point and Quantico Pier) to Buoy 33 near Dahlgren, Virginia N38° 23' 22.78"/W77° 1' 45.50" (one mile southeast of Mathias Point).

Estuarine waters includes all tidal tributaries that enter the Potomac River from Buoy 33 the downstream transition zone boundary to the mouth of the Potomac River (Buoy 44B).

5. Chesapeake Bay, Atlantic Ocean, and small coastal basins. Estuarine waters include the Atlantic Ocean tidal tributaries, and the Chesapeake Bay and its small coastal basins from the Virginia state line to the mouth of the bay (a line from Cape Henry drawn through Buoys 3 and 8 to Fishermans Island), and its tidal tributaries, excluding the Potomac tributaries and those tributaries listed above.

6. Chowan River Basin. Tidal freshwater includes the Northwest River and its tidal tributaries from the Virginia-North Carolina state line to the free flowing portion, the Blackwater River and its tidal tributaries from the Virginia-North Carolina state line to the end of tidal waters at approximately state route 611 at river mile 20.90, the Nottoway River and its tidal tributaries from the Virginia-North Carolina state line to the end of tidal waters at approximately Route 674, and the North Landing River and its tidal tributaries from the Virginia-North Carolina state line to the Great Bridge Lock.

Transition zone includes Back Bay and its tributaries in the City of Virginia Beach to the Virginia-North Carolina state line.

D. Site-specific modifications to numerical water quality criteria.

1. The board may consider site-specific modifications to numerical water quality criteria in subsection B of this section where the applicant or permittee demonstrates that the alternate numerical water quality criteria are sufficient to protect all designated uses (see 9VAC25-260-10) of that particular surface water segment or body.

2. Any demonstration for site-specific human health criteria shall be restricted to a reevaluation of the bioconcentration or bioaccumulation properties of the pollutant. The exceptions to this restriction are for site-specific criteria for taste, odor, and aesthetic compounds noted by double asterisks in subsection B of this section and nitrates.

3. Site-specific temperature requirements are found in 9VAC25-260-90.

4. Procedures for promulgation and review of site-specific modifications to numerical water quality criteria resulting from subdivisions 1 and 2 of this subsection.

a. Proposals describing the details of the site-specific study shall be submitted to the board's staff for approval prior to commencing the study.

b. Any site-specific modification shall be promulgated as a regulation in accordance with the Administrative Process Act. All site-specific modifications shall be listed in 9VAC25-260-310 (Special standards and requirements).

E. Variances to water quality standards.

1. A variance from numeric criteria may be granted to a discharger if it can be demonstrated that one or more of the conditions in 9VAC25-260-10 G H limit the attainment of one or more specific designated uses.

a. Variances shall apply only to the discharger to whom they are granted and shall be reevaluated and either continued, modified or revoked at the time of permit issuance. At that time the permittee shall make a showing that the conditions for granting the variance still apply.

b. Variances shall be described in the public notice published for the permit. The decision to approve a variance shall be subject to the public participation requirements of the Virginia Pollutant Discharge Elimination System (VPDES) Permit Regulation, 9VAC25-31 (Permit Regulation).

c. Variances shall not prevent the maintenance and protection of existing uses or exempt the discharger or regulated activity from compliance with other appropriate technology or water quality-based limits or best management practices.

d. Variances granted under this section shall not apply to new discharges.

e. Variances shall be submitted by the department's Division of Scientific Research or its successors to the Environmental Protection Agency for review and approval/disapproval.

f. A list of variances granted shall be maintained by the department's Division of Scientific Research or its successors.

2. None of the variances in this subsection shall apply to the halogen ban section (9VAC25-260-110) or temperature criteria in 9VAC25-260-50 if superseded by § 316(a) of the Clean Water Act requirements. No variances in this subsection shall apply to the criteria that are designed to protect human health from carcinogenic and noncarcinogenic toxic effects (subsection B of this section) with the exception of the metals, and the taste, odor, and aesthetic compounds noted by double asterisks and nitrates, listed in subsection B of this section.

F. Water effect ratio.

1. A water effects ratio (WER) shall be determined by measuring the effect of receiving water (as it is or will be affected by any discharges) on the bioavailability or toxicity of a metal by using standard test organisms and a metal to conduct toxicity tests simultaneously in receiving water and laboratory water. The ratio of toxicities of the metal(s) in the two waters is the WER (toxicity in receiving water divided by toxicity in laboratory water = WER). Once an acceptable WER for a metal is established, the numerical value for the metal in subsection B of this section is multiplied by the WER to produce an instream concentration that will protect designated uses. This instream concentration shall be utilized in permitting decisions.

2. The WER shall be assigned a value of 1.0 unless the applicant or permittee demonstrates to the department's satisfaction in a permit proceeding that another value is appropriate, or unless available data allow the department to compute a WER for the receiving waters. The applicant or permittee is responsible for proposing and conducting the study to develop a WER. The study may require multiple testing over several seasons. The applicant or permittee shall obtain the department's Division of Scientific Research or its successor approval of the study protocol and the final WER.

3. The Permit Regulation at 9VAC25-31-230 C requires that permit limits for metals be expressed as total recoverable measurements. To that end, the study used to establish the WER may be based on total recoverable measurements of the metals.

4. The Environmental Protection Agency views the WER in any particular case as a site-specific criterion. Therefore, the department's Division of Scientific Research or its successor shall submit the results of the study to the Environmental Protection Agency for review and approval/disapproval within 30 days of the receipt of certification from the state's Office of the Attorney General. Nonetheless, the WER is established in a permit proceeding, shall be described in the public notice associated with the permit proceeding, and applies only to the applicant or permittee in that proceeding. The department's action to approve or disapprove a WER is a case decision, not an amendment to the present regulation.

The decision to approve or disapprove a WER shall be subject to the public participation requirements of the Permit Regulation, 9VAC25-31-260 et seq. A list of final WERs will be maintained by the department's Division of Scientific Research or its successor.

5. A WER shall not be used for the freshwater and saltwater chronic mercury criteria or the freshwater acute and chronic selenium criteria.

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from VR680-21-01.14B, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Errata, 14:12 VA.R. 1937 March 2, 1998; amended, Virginia Register Volume 19, Issue 23, eff. August 27, 2003; Volume 20, Issue 9, eff. February 12, 2004; Volume 25, Issue 12, eff. after EPA approval.

Part II
Standards with More Specific Application

[ 9VAC25-260-160. Fecal coliform bacteria; shellfish waters.

In all open ocean or estuarine waters capable of propagating shellfish or in specific areas where public or leased private shellfish beds are present, and including those waters on which condemnation or restriction classifications are established by the State Department of Health, the following criteria for fecal coliform bacteria shall apply:

The geometric mean fecal coliform value for a sampling station shall not exceed an MPN (most probable number) or MF (membrane filtration using mTEC culture media) of 14 per 100 milliliters (ml). The estimated 90th percentile shall not exceed an MPN of 43 per 100 ml for a 5-tube , 3-dilution decimal dilution test or an MPN of 49 per 100 ml for a 3-tube , 3-dilution decimal dilution test or MF test of 31 CFU (colony forming units) per 100 ml. ]

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from VR680-21-02.1, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Volume 19, Issue 7, eff. January 15, 2003; Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-170. Bacteria; other recreational waters.

A. In surface waters, except shellfish waters and certain waters identified in subsections B and C of this section, the The following bacteria criteria (colony forming units (CFU)/100 ml) shall apply to protect primary contact recreational uses in surface waters, except waters identified in subsection B of this section:

1. Fecal coliform bacteria shall not exceed a geometric mean of 200 fecal coliform bacteria per 100 ml of water for two or more samples over a calendar month nor shall more than 10% of the total samples taken during any calendar month exceed 400 fecal coliform bacteria per 100 ml of water. This criterion shall not apply for a sampling station after the bacterial indicators described in subdivision 2 of this subsection have a minimum of 12 data points or after June 30, 2008, whichever comes first.

2. E. coli and enterococci bacteria per 100 ml of water shall not exceed the following:

¹For two or more samples taken during any calendar month.

²No single sample maximum for enterococci and E. coli shall exceed a 75% upper one-sided confidence limit based on a site-specific log standard deviation. If site data are insufficient to establish a site-specific log standard deviation, then 0.4 shall be used as the log standard deviation in fresh water and 0.7 shall be as the log standard deviation in saltwater and transition zone. Values shown are based on a log standard deviation of 0.4 in freshwater and 0.7 in saltwater.

³See 9 VAC 25-260-140 C for freshwater and transition zone delineation.

E.coli bacteria shall not exceed a monthly geometric mean of 126 CFU/100 ml in freshwater [ , or E.coli bacteria shall not exceed a monthly geometric mean of 206 CFU/100 ml in freshwater ].

Enterococci bacteria shall not exceed a monthly geometric mean of 35 CFU/100 ml in transition and saltwater.

1. See 9VAC25-260-140 C for boundary delineations for freshwater, transition and saltwater.

2. Geometric means shall be calculated using all data collected during any calendar month with a minimum of four weekly samples.

3. If there [ is are ] insufficient data to calculate monthly geometric means in freshwater, no more than 10% of the total samples in the assessment period shall exceed 235 E.coli CFU/100 ml [ , or if there is insufficient data to calculate monthly geometric means in freshwater, no more than 10% of the total samples in the assessment period shall exceed 384 E.coli CFU/100 ml ].

4. If there [ is are ] insufficient data to calculate monthly geometric means in transition and saltwater, no more than 10% of the total samples in the assessment period shall exceed enterococci 104 CFU/100 ml.

5. For beach advisories or closures, a single sample maximum of 235 E.coli CFU/100 ml in freshwater and a single sample maximum of 104 enterococci CFU/100 ml in saltwater and transition zones shall apply [ , or for beach advisories or closures, a single sample maximum of 384 E.coli CFU/100 ml in freshwater and a single sample maximum of 104 enterococci CFU/100 ml in saltwater and transition zones shall apply ].

B. Notwithstanding the above, all sewage discharges shall be disinfected to achieve the applicable bacteria concentrations in subdivision A 2 of this section prior to discharge.

However, the board, with the advice of the State Department of Health, may determine that reduced or no disinfection of a discharge is appropriate on a seasonal or year-round basis. In making such a determination, the board shall consider the designated uses of these waters and the seasonal nature of those uses. Such determinations will be made during the process of approving, issuing, or reissuing the discharge permit and shall be in conformance with a board approved site-specific use-attainability analysis performed by the permittee. When making a case-by-case determination concerning the appropriate level of disinfection for sewage discharges into these waters, the board shall provide a 45-day public notice period and opportunity for a public hearing.

C. Surface waters, or portions of these, may be designated in accordance with 9VAC25-260-10 to protect secondary contact recreation.

1. Sewage discharges to secondary contact recreational waters shall meet the requirements of the disinfection policy set forth in subsection B of this section.

2. In surface waters, except shellfish waters, designated for secondary contact recreation under this subsection, the B. The following bacteria criteria per 100 ml (CFU/100 ml) of water shall apply:

¹Calendar month average for two or more samples.

²No single sample maximum for enterococci and E. coli in secondary contact waters shall exceed a 75% upper one-sided confidence limit based on a site-specific log standard deviation. If site data are insufficient to establish a site-specific log standard deviation, then 0.4 shall be the log standard deviation in fresh and transition zone waters and 0.7 shall be the log standard deviation in saltwater. Values shown are based on a log standard deviation of 0.4 in freshwater and 0.7 in saltwater.

³See subsection 9 VAC 25-260-140 C for freshwater and transition zone delineation.

E.coli bacteria shall not exceed a monthly geometric mean of 630 CFU/100 ml in freshwater.

Enterococci bacteria shall not exceed a monthly geometric mean of 175 CFU/100 ml in transition and saltwater.

1. See 9VAC25-260-140 C for boundary delineations for freshwater, transition and saltwater.

2. Geometric means shall be calculated using all data collected during any calendar month with a minimum of four weekly samples.

3. If there is insufficient data to calculate monthly geometric means in freshwater, no more than 10% of the total samples in the assessment period shall exceed 1173 E.coli CFU/100 ml.

4. If there is insufficient data to calculate monthly geometric means in transition and saltwater, no more than 10% of the total samples in the assessment period shall exceed 519 enterococci CFU/100 ml.

5. Where the existing water quality for bacteria is below the geometric mean criteria in a water body designated for secondary contact in subdivision 6 of this subsection that higher water quality will be maintained in accordance with 9VAC25-260-30 A 2.

3. 6. Surface waters designated under this subsection are as follows:

a. (Reserved)

b. (Reserved)

c. (Reserved)

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from VR680-21-02.2, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Volume 19, Issue 7, eff. January 15, 2003; Volume 20, Issue 9, eff. February 12, 2004; Volume 25, Issue 12, eff. after EPA approval.

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.

B. Submerged aquatic vegetation and water clarity. If the submerged aquatic vegetation (SAV) acres in this subsection are met in any individual Chesapeake Bay Program segment as described in subsection D of this section, then the shallow water submerged aquatic vegetation use is met in that segment. If the SAV acres in this subsection are not met in any individual Chesapeake Bay Program segment, then the water clarity criteria shall apply to the water clarity acres in that segment. If these water clarity criteria are met to the bottom water sediment interface for the number of water clarity acres in that segment, then the shallow-water submerged aquatic vegetation use is met; regardless of the number of acres of SAV in that segment. Attainment of the shallow-water submerged aquatic vegetation designated use shall be determined using any [ one ] of the following criteria:

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 most recent five years shall be used data assessment window.

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.

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.

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 most recent five years shall be used the data assessment window.

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 285-07, EPA 903-R-07-003) addenda. If no reference curve is published, the cumulative frequency distribution reference curve in Figure 1, which represents 10% allowable exceedences equally distributed between time and space, shall be the applicable reference curve. An exception to this requirement is in measuring attainment of the SAV and water clarity acres, which are compared directly to the criteria.

[ Figure 1.

 ]

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from Virginia Register Volume 21, Issue 23, eff. June 24, 2005; amended, Volume 25, Issue 12, eff. after EPA approval.

[ 9VAC25-260-187. Criteria for man-made lakes and reservoirs to protect aquatic life and recreational designated uses from the impacts of nutrients.

A. The criteria in subsection B of this section apply to the man-made lakes and reservoirs listed in this section. Additional man-made lakes and reservoirs may be added as new reservoirs are constructed or monitoring data become available from outside groups or future agency monitoring.

B. Whether or not algicide treatments are used, the chlorophyll a criteria apply to all waters on the list. The total phosphorus criteria apply only if a specific man-made lake or reservoir received algicide treatment during the monitoring and assessment period of April 1 through October 31.

The 90th percentile of the chlorophyll a data collected at one meter or less within the lacustrine portion of the man-made lake or reservoir between April 1 and October 31 shall not exceed the chlorophyll a criterion for that water body in each of the two most recent monitoring years that chlorophyll a data are available. For a water body that received algicide treatment, the median of the total phosphorus data collected at one meter or less within the lacustrine portion of the man-made lake or reservoir between April 1 and October 31 shall not exceed the total phosphorus criterion in each of the two most recent monitoring years that total phosphorus data are available.

Monitoring data used for assessment shall be from sampling location(s) within the lacustrine portion where observations are evenly distributed over the seven months from April 1 through October 31 and are in locations that are representative, either individually or collectively, of the condition of the man-made lake or reservoir.

C. When the board determines that the applicable criteria in subsection B of this section for a specific man-made lake or reservoir are exceeded, the board shall consult with the Department of Game and Inland Fisheries regarding the status of the fishery in determining whether or not the designated use for that water body is being attained. If the designated use of the subject water body is not being attained, the board shall assess the water body as impaired in accordance with § 62.1-44.19:5 of the Code of Virginia. If the designated use is being attained, the board shall assess the water body as impaired in accordance with § 62.1-44.19:5 of the Code of Virginia until site-specific criteria are adopted and become effective for that water body.

D. If the nutrient criteria specified for a man-made lake or reservoir in subsection B of this section do not provide for the attainment and maintenance of the water quality standards of downstream waters as required in 9VAC25-260-10 C, the nutrient criteria herein may be modified on a site-specific basis to protect the water quality standards of downstream waters. ]

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from Virginia Register Volume 24, Issue 4, eff. August 14, 2007amended, Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-290. Tidal water sampling. (Repealed.)

Samples for determining compliance with standards established for estuarine or open ocean waters shall be collected at slack before flood tide or slack before ebb tide.

Statutory Authority

§§ 62.1-44.15(3) and (10) of the Code of Virginia.

Historical Notes

Derived from VR680-21-06.5, eff. May 20, 1992; repealed, Volume 25, Issue 12, eff. after EPA approval.

Part VII
Special Standards and Scenic Rivers Listings

9VAC25-260-310. Special standards and requirements.

The special standards are shown in small letters to correspond to lettering in the basin tables. The special standards are as follows:

a. Shellfish waters. In all open ocean or estuarine waters capable of propagating shellfish or in specific areas where public or leased private shellfish beds are present, including those waters on which condemnation [ or restriction ] classifications are established by the State Department of Health, the following criteria for fecal coliform bacteria will apply:

The geometric mean fecal coliform value for a sampling station shall not exceed an MPN (most probable number) [ or MF (membrane filtration using mTEC culture media) ] of 14 per 100 [ ml milliliters (ml) ] of sample and the [ estimated ] 90th percentile shall not exceed [ an MPN of ] 43 [ per 100 ml ] for a 5-tube [ , 3-dilution decimal dilution ] test or [ an MPN of ] 49 [ per 100 ml ] for a 3-tube [ , 3-dilution decimal dilution ] test [ or MF test of 31 CFU (colony forming units) per 100 ml ].

The shellfish area is not to be so contaminated by radionuclides, pesticides, herbicides, or fecal material that the consumption of shellfish might be hazardous.

b. Policy for the Potomac Embayments. At its meeting on September 12, 1996, the board adopted a policy (9VAC25-415. Policy for the Potomac Embayments) to control point source discharges of conventional pollutants into the Virginia embayment waters of the Potomac River, and their tributaries, from the fall line at Chain Bridge in Arlington County to the Route 301 bridge in King George County. The policy sets effluent limits for BOD₅, total suspended solids, phosphorus, and ammonia, to protect the water quality of these high profile waterbodies.

c. Cancelled.

d. Cancelled.

e. Cancelled.

f. Cancelled.

g. Occoquan watershed policy. At its meeting on July 26, 1971 (Minute 10), the board adopted a comprehensive pollution abatement and water quality management policy for the Occoquan watershed. The policy set stringent treatment and discharge requirements in order to improve and protect water quality, particularly since the waters are an important water supply for Northern Virginia. Following a public hearing on November 20, 1980, the board, at its December 10-12, 1980 meeting, adopted as of February 1, 1981, revisions to this policy (Minute 20). These revisions became effective March 4, 1981. Additional amendments were made following a public hearing on August 22, 1990, and adopted by the board at its September 24, 1990, meeting (Minute 24) and became effective on December 5, 1990. Copies are available upon request from the Department of Environmental Quality.

h. Cancelled.

i. Cancelled.

j. Cancelled.

k. Cancelled.

l. Cancelled.

m. The following effluent limitations apply to wastewater treatment facilities in the entire Chickahominy watershed above Walker's Dam (this excludes effluents discharges consisting solely of stormwater):

n. No sewage discharges, regardless of degree of treatment, should be allowed into the James River between Bosher and Williams Island Dams.

o. The concentration and total amount of impurities in Tuckahoe Creek and its tributaries of sewage origin shall be limited to those amounts from sewage, industrial wastes, and other wastes which are now present in the stream from natural sources and from existing discharges in the watershed.

p. Cancelled.

q. Cancelled.

r. Cancelled.

s. Chlorides not to exceed 40 mg/l at any time. Cancelled.

t. Cancelled.

u. Maximum temperature for the New River Basin from West Virginia state line upstream to the Giles-Montgomery County line:

The maximum temperature shall be 27°C (81°F) unless caused by natural conditions; the maximum rise above natural temperatures shall not exceed 2.8°C (5°F).

This maximum temperature limit of 81°F was established in the 1970 water quality standards amendments so that Virginia temperature criteria for the New River would be consistent with those of West Virginia, since the stream flows into that state.

v. The maximum temperature of the New River and its tributaries (except trout waters) from the Montgomery-Giles County line upstream to the Virginia-North Carolina state line shall be 29°C (84°F).

w. Cancelled.

x. Clinch River from the confluence of Dumps Creek at river mile 268 at Carbo downstream to river mile 255.4. The special water quality criteria for copper (measured as total recoverable) in this section of the Clinch River are 12.4 μg/l for protection from chronic effects and 19.5 μg/l for protection from acute effects. These site-specific criteria are needed to provide protection to several endangered species of freshwater mussels.

y. Tidal freshwater Potomac River and tidal tributaries that enter the tidal freshwater Potomac River from Cockpit Point (below Occoquan Bay) to the fall line at Chain Bridge. During November 1 through February 14 of each year the 30-day average concentration of total ammonia nitrogen (in mg N/L) shall not exceed, more than once every three years on the average, the following chronic ammonia criterion:

MAX = temperature in °C or 7, whichever is greater.

The default design flow for calculating steady state waste load allocations for this chronic ammonia criterion is the 30Q10, unless statistically valid methods are employed which demonstrate compliance with the duration and return frequency of this water quality criterion.

z. A site specific dissolved copper aquatic life criterion of 16.3 μg/l for protection from acute effects and 10.5 μg/l for protection from chronic effects applies in the following area:

Little Creek to the Route 60 (Shore Drive) bridge including Little Channel, Desert Cove, Fishermans Cove and Little Creek Cove.

Hampton Roads Harbor including the waters within the boundary lines formed by I-664 (Monitor-Merrimac Bridge Tunnel) and I-64 (Hampton Roads Bridge Tunnel), Willoughby Bay and the Elizabeth River and its tidal tributaries.

This criterion reflects the acute and chronic copper aquatic life criterion for saltwater in 9VAC25-260-140 B X a water effect ratio. The water effect ratio was derived in accordance with 9VAC25-260-140 F.

aa. The following site-specific dissolved oxygen criteria apply to the tidal Mattaponi and Pamunkey Rivers and their tidal tributaries because of seasonal lower dissolved oxygen concentration due to the natural oxygen depleting processes present in the extensive surrounding tidal wetlands. These criteria apply June 1 through September 30 to Chesapeake Bay segments MPNTF, MPNOH, PMKTF, PMKOH and are implemented in accordance with subsection D of 9VAC25-260-185. These criteria supersede the open water criteria listed in subsection A of 9VAC25-260-185.

A site-specific pH criterion of 5.0-8.0 applies to the tidal freshwater Mattaponi Chesapeake Bay segment MPNTF to reflect natural conditions.

bb. The following site specific numerical chlorophyll a criteria apply March 1 through May 31 and July 1 through September 30 as seasonal means to the tidal James River (excludes tributaries) segments JMSTF2, JMSTF1, JMSOH, JMSMH, JMSPH and are implemented in accordance with subsection D of 9VAC25-260-185.

cc. For Mountain Lake in Giles County, chlorophyll a shall not exceed 6 µg/L at a depth of 6 meters and orthophosphate-P shall not exceed 8 µg/L at a depth of one meter or less.

dd. For Lake Drummond, located within the boundaries of Chesapeake and Suffolk in the Great Dismal Swamp, chlorophyll a shall not exceed 35 µg/L and total phosphorus shall not exceed 40 µg/L at a depth of one meter or less.

ee. Lake Curtis in Stafford County has a pH standard of 5.5-9.6, which is protective of the aquatic life in this reservoir and is a result of the fertilization techniques used to manage the fishery.

ff. John H. Kerr Reservoir at the Clarksville water supply intake has a dissolved manganese criterion of 50 µg/l to protect the acceptable taste, odor or aesthetic quality of the drinking water.

gg. Little Calfpasture River from the Goshen Dam to 0.76 miles above its confluence with the Calfpasture River has a stream condition index (A Stream Condition Index for Virginia Non-Coastal Streams, September 2003, Tetra Tech, Inc.) of at least 20.5 to protect the subcategory of aquatic life that exists here as a result of the hydrologic modification. From 0.76 miles to 0.02 miles above its confluence with the Calfpasture River, aquatic life conditions are expected to gradually recover and meet the general aquatic life uses at 0.02 miles above its confluence with the Calfpasture River.

hh. Maximum temperature for these seasonally stockable trout waters is 31°C and applies May 1 through October 31.

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from VR680-21-07.1, eff. May 20, 1992; amended July 1, 1992; amended, Virginia Register Volume 13, Issue 12, eff. April 2, 1997; Volume 14, Issue 4, eff. December 10, 1997; Volume 19, Issue 23, eff. August 27, 2003; Volume 20, Issue 9, eff. February 12, 2004; Volume 22, Issue 11, eff. January 12, 2006; Volume 24, Issue 4, eff. August 14, 2007; Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-320. Scenic rivers. (Repealed.)

The following section recognizes waters which the General Assembly has determined to be of special ecological or recreational significance to the state. The designation of a scenic river and the significance of this designation are the subject of the Scenic Rivers Act (§ 10.1-400 et seq. of the Code of Virginia) and are listed here for informational purposes only.

POTOMAC RIVER BASIN

POTOMAC RIVER SUBBASIN

Goose Creek from its confluence with the Potomac River upstream to the Fauquier-Loudoun County line (7+ miles).

Catoctin Creek in Loudoun County from its confluence with the Potomac River upstream to the Town of Waterford (16+ miles).

SHENANDOAH RIVER SUBBASIN

The Shenandoah River in Clarke County from the Warren-Clarke County line to Lockes Landing (14+ miles).

JAMES RIVER BASIN

The Saint Marys River in Augusta County within the George Washington National Forest. (6+ miles).

Rivanna River from its confluence with the James River upstream to the base of the dam at the Woolen Mills in the City of Charlottesville to the junction of the Rivanna with the James River (37+ miles).

Appomattox River from the Route 36 bridge crossing in the City of Petersburg upstream to the abutment dam located about 1.3 miles below Lake Chesdin (5+ miles).

The James River from Orleans Street extended in the City of Richmond westward to the 1970 corporate limits of the city (8+ miles).

The Upper James River from a point two miles below Eagle Rock to the Route 630 bridge in Springwood (14+/- miles).

Chickahominy River from Route 360 to the junction of the Hanover/Henrico/New Kent County line in Hanover County (10.2+ miles).

The Moormans River in Albemarle County, from the foot of the dam of the Charlottesville water supply reservoir to the junction with the Mechums River below Route 601 (13+ miles).

Rockfish River from the Route 693 bridge in Schuyler to its confluence with the James River (9.75+ miles).

Lower James River, from an unnamed tributary to the James River approximately 1.2 miles east of Trees Point in Charles City County (northside) and Upper Chippokes Creek (southside) to Grices Run (northside) and Lawnes Creek (southside) (25+ miles).

RAPPAHANNOCK RIVER BASIN

Rappahannock River in Rappahannock, Culpeper, Fauquier, Stafford, and Spotsylvania Counties and the City of Fredericksburg from its headwaters near Chester Gap to the Ferry Farm-Mayfield Bridge (86+/- miles).

ROANOKE RIVER BASIN

ROANOKE RIVER SUBBASIN

Roanoke (Staunton) River from State Route 360 upstream to State Route 761 at the Long Island Bridge (40.5 +/- miles).

CHOWAN AND DISMAL SWAMP BASIN

CHOWAN RIVER SUBBASIN

Nottoway River in Sussex County from the Route 40 bridge at Stony Creek to the Southampton County line (33+ miles).

North Meherrin River in Lunenburg County from the Route 712 bridge to the confluence with the Meherrin River (7.5 miles).

ALBEMARLE SOUND SUBBASIN

The North Landing River from the North Carolina line to the bridge at Route 165, Pocaty River from its junction with North Landing River to the Blackwater Road Bridge, West Neck Creek from the junction with the North Landing River to Indian River Road Bridge, and Blackwater Creek from the junction with the North Landing River to its confluence, approximately 4.2 miles, of an unnamed tributary 1.75+/- miles west of Blackwater Road (26+ miles).

TENNESSEE AND BIG SANDY RIVER BASINS

CLINCH RIVER SUBBASIN

Guest River from a point 100 feet downstream of the Route 72 Bridge to the junction with the Clinch River in Scott and Wise County (6.5+ miles).

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from VR680-21-07.2, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Volume 20, Issue 9, eff. February 12, 2004; repealed, Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-350. Designation of nutrient enriched waters.

A. The following state waters are hereby designated as "nutrient enriched waters":

1. Smith Mountain Lake and all tributaries* of the impoundment upstream to their headwaters;

2. Lake Chesdin from its dam upstream to where the Route 360 bridge (Goodes Bridge) crosses the Appomattox River, including all tributaries to their headwaters that enter between the dam and the Route 360 bridge; (Repealed.)

3. South Fork Rivanna Reservoir and all tributaries of the impoundment upstream to their headwaters; (Repealed.)

4. New River and its tributaries, except Peak Creek above Interstate 81, from Claytor Dam upstream to Big Reed Island Creek (Claytor Lake).

5. Peak Creek from its headwaters to its mouth (confluence with Claytor Lake), including all tributaries to their headwaters;

6. through 20. (Repealed.)

7. (Repealed.)

8. (Repealed.)

9. (Repealed.)

10. (Repealed.)

11. (Repealed.)

12. (Repealed.)

13. (Repealed.)

14. (Repealed.)

15. (Repealed.)

16. (Repealed.)

17. (Repealed.)

18. (Repealed.)

19. (Repealed.)

20. (Repealed.)

21. Tidal freshwater Blackwater River from the Norfolk and Western railway bridge at Burdette, Virginia, and tidal freshwater Nottoway River from the Norfolk and Western railway bridge at Courtland, Virginia, to the state line, including all tributaries to their headwaters that enter the tidal freshwater portions of the Blackwater River and the Nottoway River; and

22. Stony Creek from its confluence with the North Fork Shenandoah River to its headwaters including all named and unnamed tributaries to their headwaters. (Repealed.)

B. Whenever any water body is designated as "nutrient enriched waters," the board shall modify the VPDES permits of point source dischargers into the "nutrient enriched waters" as provided in the board's Policy for Nutrient Enriched Waters (9VAC25-40).

*When the word "tributaries" is used in this standard, it does not refer to the mainstem of the water body that has been named.

Statutory Authority

§ 62.1-44.15(3a) of the Code of Virginia.

Historical Notes

Derived from VR680-21-07.3-3, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Errata, 14:12 VA.R. 1937 March 2, 1998; amended, Virginia Register Volume 16, Issue 17, eff. June 7, 2000; Volume 21, Issue 23, eff. June 24, 2005; Volume 25, Issue 12, eff. after EPA approval.

Part IX
River Basin Section Tables

9VAC25-260-360. Section number and description columns.

A. Basin descriptions. The tables that follow divide the state's surface waters into [ nine 10 ]  river basins, some with subbasins: Potomac River Basin (Potomac and Shenandoah Subbasins), James River Basin (Appomattox River Subbasin), Rappahannock River Basin, Roanoke River Basin (Roanoke and Yadkin Subbasins), Yadkin River Basin, Chowan and Dismal Swamp Basin (Chowan and Albemarle Sound Subbasins), Tennessee and Big Sandy Basins (Big Sandy, Clinch and Holston Subbasins), Chesapeake Bay, Atlantic Ocean and Small Coastal Basin, York River Basin and New River Basin. (See Figure 2.)

Figure 2.

Each basin is further divided into sections. Each section is assigned a class, represented by Roman Numerals I through VII, based on its geographic location or, in the case of trout waters, on its use. Descriptions of these classes are found in 9VAC25-260-50.

B. Potomac water supplies (raw water intakes). The Leesburg and County of Fairfax intakes in the Potomac are in Maryland waters and the board cannot adopt the public water supply criteria in 9VAC25-260-140 B to apply at the raw water intake points. However, applications to discharge into, or otherwise alter the physical, chemical, or biological properties of Virginia waters within an area five miles upstream of the intake will be reviewed on a case-by-case basis to ensure that they will protect the water supply. Basin sections where this would be applicable are shown with an asterisk (*) in the basin and section description columns.

Statutory Authority

§ 62.1-44.15(3a) of the Code of Virginia.

Historical Notes

Derived from VR680-21-08.1, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-380. Special standards column.

A. Bacteria criteria. All surface waters have criteria for fecal coliform bacteria. The bacteria criteria for shellfish waters are set forth in 9VAC25-260-160; the criteria applying to all other surface recreational waters are found in 9VAC25-260-170. The letter "a" in the special standards column next to a river basin section indicates that there are shellfish waters somewhere within that section and the bacteria criteria for shellfish waters applies to those shellfish waters. (It should be noted that even though the column contains the letter "a" the entire section may not be shellfish waters.)

B. Natural variation. In some cases natural water quality does not fall within the criteria set by these standards. (For example streams in some areas of the state may naturally exceed the usual pH range of 6.0 to 9.0.) In these instances the board may have set more appropriate criteria that reflect natural quality, and this special limit is shown in the special standards column.

C. Additional requirements. In other cases the basic water quality parameters of DO, pH, temperature, and bacteria have not been sufficient to protect water quality in certain areas, and effluent limits or treatment requirements have been established for these areas. This fact is also indicated in the special standards column. If the applicable standard was too long to print in its entirety in that column, the column contains only a lower case letter, and the standard itself will be found in the special standards 9VAC25-260-310 under that letter.

D. Other special standards or designations.

1. Public water supplies (PWS). Sections that are public water supplies are indicated in the special standards column with a PWS. This designation indicates that additional criteria are applicable in this section. See 9VAC25-260-140 B for applicable criteria. Taste and odor criteria to maintain acceptable taste, odor or aesthetic quality of drinking water apply at the drinking water intake.

2. Nutrient enriched waters (NEW). If a section contains a waterbody that has been designated as nutrient enriched in 9VAC25-260-350, the special standards column indicates this with the letters "NEW-" followed by a number. The appropriate waterway can be found listed in 9VAC25-260-350. The entire section is not necessarily nutrient enriched, only that portion specifically listed in 9VAC25-260-350.

3. Exceptional state waters (ESW). If a section contains a waterbody that has been designated as exceptional state waters in 9VAC25-260-30 A 3 the special standard column indicates this with ESW followed by a number. The appropriate waterway can be found listed in 9VAC25-260-30 A 3 c. The entire section within the basin table is not necessarily designated as exceptional state waters, only that portion specifically listed in 9VAC25-260-30 A 3 c.

4. If a section contains a waterbody that has been assigned a special standard (indicated by lower case letters in the special standards column), the appropriate waterway can be found listed in 9VAC25-260-310. The special standard does not necessarily apply to the entire section, only that portion specifically listed in 9VAC25-260-310.

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from VR680-21-08.3, eff. May 20, 1992; amended, Virginia Register Volume 14, Issue 4, eff. December 10, 1997; Volume 20, Issue 9, eff. February 12, 2004; Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-390. Potomac River Basin (Potomac River Subbasin).

Potomac River Subbasin

Statutory Authority

§ 62.1-44.15 of the Code of Virginia.

Historical Notes

Derived from VR680-21-08.4, eff. May 20, 1992; amended, Virginia Register Volume 13, Issue 12, eff. April 2, 1997; Volume 14, Issue 4, eff. December 10, 1997; Errata, 14:12 VA.R. 1937 March 2, 1998; amended, Virginia Register Volume 19, Issue 23, eff. August 27, 2003; Volume 20, Issue 9, eff. February 12, 2004; Volume 25, Issue 12, eff. after EPA approval.

9VAC25-260-400. Potomac River Basin (Shenandoah River Subbasin).

Shenandoah River Subbasin