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9VAC25-260-5

Part I
Surface Water Standards with General, Statewide Application

9VAC25-260-5. Definitions.

The following words and terms when used in this chapter shall have the following meanings unless the context clearly indicates otherwise:

"Algicides" means chemical substances, most commonly copper-based, used as a treatment method to control algae growths.

"Board" means State Water Control Board.

"Chesapeake Bay and its tidal tributaries" means all tidally influenced waters of the Chesapeake Bay; western and eastern coastal embayments and tributaries; James, York, Rappahannock and Potomac Rivers and all their tidal tributaries to the end of tidal waters in each tributary (in larger rivers this is the fall line); and includes subdivisions 1, 2, 3, 4, 5, and 6 of 9VAC25-260-390, subdivisions 1, 1b, 1d, 1f and 1o of 9VAC25-260-410, subdivisions 5 and 5a of 9VAC25-260-415, subdivisions 1 and 1a of 9VAC25-260-440, subdivisions 2, 3, 3a, 3b and 3e of 9VAC25-260-520, and subdivision 1 of 9VAC25-260-530. This definition does not include free flowing sections of these waters.

"Criteria" means elements of the board's water quality standards, expressed as constituent concentrations, levels, or narrative statements, representing a quality of water that supports a particular use.  When criteria are met, water quality will generally protect the designated use.

"Department" or "DEQ" means the Virginia Department of Environmental Quality.

"Designated uses" means those uses specified in water quality standards for each water body waterbody or segment whether or not they are being attained.

"Drifting organisms" means planktonic organisms that are dependent on the current of the water for movement.

"Epilimnion" means the upper layer of nearly uniform temperature in a thermally stratified man-made lake or reservoir listed in 9VAC25-260-187 B.

"Existing uses" means those uses actually attained in the water body waterbody on or after November 28, 1975, whether or not they are included in the water quality standards.

"Lacustrine" means the zone within a lake or reservoir that corresponds to nonflowing lake-like conditions such as those near the dam. The other two zones within a reservoir are riverine (flowing, river-like conditions) and transitional (transition from river to lake conditions).

"Man-made lake or reservoir" means a constructed impoundment.

"Mixing zone" means a limited area or volume of water where initial dilution of a discharge takes place and where numeric water quality criteria can be exceeded but designated uses in the water body waterbody on the whole are maintained and lethality is prevented.

"Natural lake" means an impoundment that is natural in origin. There are two natural lakes in Virginia: Mountain Lake in Giles County and Lake Drummond located within the boundaries of Chesapeake and Suffolk in the Great Dismal Swamp.

"Passing organisms" means free swimming organisms that move with a mean velocity at least equal to the ambient current in any direction.

"Primary contact recreation" means any water-based form of recreation, the practice of which has a high probability for total body immersion or ingestion of water (examples include but are not limited to swimming, water skiing, canoeing and kayaking).

"Pycnocline" means the portion of the water column where density changes rapidly because of salinity and/or temperature.  In an estuary the pycnocline is the zone separating deep, cooler more saline waters from the less saline, warmer surface waters. The upper and lower boundaries of a pycnocline are measured as a change in density per unit of depth that is greater than twice the change of the overall average for the total water column.

"Secondary contact recreation" means a water-based form of recreation, the practice of which has a low probability for total body immersion or ingestion of waters (examples include but are not limited to wading, boating and fishing).

"Swamp waters" means waters with naturally occurring low pH and low dissolved oxygen caused by: (i) low flow velocity that prevents mixing and reaeration of stagnant, shallow waters and (ii) decomposition of vegetation that lowers dissolved oxygen concentrations and causes tannic acids to color the water and lower the pH.

"Use attainability analysis" means a structured scientific assessment of the factors affecting the attainment of the use which may include physical, chemical, biological, and economic factors as described in 9VAC25-260-10 H.

"Water quality standards" means provisions of state or federal law which consist of a designated use or uses for the waters of the Commonwealth and water quality criteria for such waters based upon such uses. Water quality standards are to protect the public health or welfare, enhance the quality of water and serve the purposes of the State Water Control Law (§ 62.1-44.2 et seq. of the Code of Virginia) and the federal Clean Water Act (33 USC § 1251 et seq.).

"Wetlands" means those areas that are inundated or saturated by surface water or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.

9VAC25-260-50

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

CLASS

DESCRIPTION OF WATERS

DISSOLVED OXYGEN (mg/l)****

pH

Max. Temp.
(°C)

Min.

Daily Avg.

I

Open Ocean

5.0

‑‑

6.0-9.0

‑‑

II

Tidal Waters in the Chowan Basin and the Atlantic Ocean Basin

4.0

5.0

6.0-9.0

‑‑

II

Tidal Waters in the Chesapeake Bay and its tidal tributaries

see 9VAC25-260-185

6.0-9.0

 

III

Nontidal Waters (Coastal and Piedmont Zones)

4.0

5.0

6.0-9.0

32

IV

Mountainous Zones Waters

4.0

5.0

6.0-9.0

31

V

Stockable Trout Waters

5.0

6.0

6.0-9.0

21

VI

Natural Trout Waters

6.0

7.0

6.0-9.0

20

VII

Swamp Waters

*

*

3.7-8.0*

**

*This classification recognizes that the natural quality of these waters may fluctuate outside of the values for D.O. and pH set forth above as water quality criteria 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 Class VII waters 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 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.

****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 and pH criteria apply only to the epilimnion of the water body waterbody. When these waters are not stratified, the dissolved oxygen and pH criteria apply throughout the water column.

9VAC25-260-140

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

A. Instream water quality conditions shall not be acutely1 or 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.

Table of Parameters6, 7

PARAMETER
CAS Number

USE DESIGNATION

AQUATIC LIFE

HUMAN HEALTH

FRESHWATER

SALTWATER

Public Water Supply3

All Other Surface Waters4

Acute1

Chronic2

Acute1

Chronic2

Acenapthene (μg/l)
83329

 

 

 

 

670

990

Acrolein (μg/l)
107028

3.0 

3.0 

 

 

6.1

9.3

Acrylonitrile (μg/l)
107131

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.51

2.5

Aldrin (μg/l)
309002

Known or suspected carcinogen; human health criteria at risk level 10-5.

3.0

 

1.3

 

0.00049

0.00050

Ammonia (μg/l)
766‑41‑7

Chronic criterion is a 30-day average concentration not to be exceeded more than once every three (3) years on the average. (see 9VAC25-260-155)

 

 

 

 

 

 

Anthracene (μg/l)
120127

 

 

 

 

8,300

40,000

Antimony (μg/l)
7440360

 

 

 

 

5.6

640

Arsenic (μg/l)5
7440382

340

150

69

36

10

 

Bacteria
(see 9VAC25-260-160 and 170)

 

 

 

 

 

 

Barium (μg/l)
7440393

 

 

 

 

2,000

 

Benzene (μg/l)
71432

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

22

510

Benzidine (μg/l)
92875

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.00086

0.0020

Benzo (a) anthracene (μg/l)
56553

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.038

0.18

Benzo (b) fluoranthene (μg/l)
205992

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.038

0.18

Benzo (k) fluoranthene (μg/l)
207089

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.038

0.18

Benzo (a) pyrene (μg/l)
50328

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.038

0.18

Bis2-Chloroethyl Ether (μg/l)
111444

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.30

5.3

Bis2-Chloroisopropyl Ether (μg/l)
108601

 

 

 

 

1,400

65,000

Bis2-Ethylhexyl Phthalate (μg/l)
117817

Known or suspected carcinogen; human health criteria at risk level 10-5.

Synonym = Di-2-Ethylhexyl Phthalate.

 

 

 

 

12

22

Bromoform (μg/l)
75252

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

43

1,400

Butyl benzyl phthalate (μg/l)
85687

 

 

 

 

1,500

1,900

Cadmium (μg/l)5
7440439

Freshwater values are a function of total hardness as calcium carbonate (CaCO3) mg/l and the WER. The minimum hardness allowed for use in the equation below shall be 25 and the maximum hardness shall be 400 even when the actual ambient hardness is less than 25 or greater than 400.

Freshwater acute criterion (μg/l)
WER [ [e {1.128[In(hardness)] – 3.828}] [e {0.8407[In(hardness)] – 3.279}] ]

Freshwater chronic criterion (μg/l)
WER [ [e {0.7852[In(hardness)] – 3.490}] [e {0.6247[In(hardness)] – 3.384}] ] CFc

WER = Water Effect Ratio = 1 unless determined otherwise under 9VAC25-260-140 F

e = natural antilogarithm

ln = natural logarithm

CFc = conversion factor (chronic)

CFc = 1.101672-[(ln hardness)(0.041838)] ]

[ 3.9 1.8 ]
CaCO3 = 100

[ 1.1 0.55 ]
CaCO3 = 100

40
X WER

8.8
X WER

5

 

Carbon tetrachloride (μg/l)
56235

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

[ 2.3 4.3 ]

 [ 16 30 ]

Carbaryl (μg/l)

63252

2.1

2.1

1.6

Chlordane (μg/l)
57749

Known or suspected carcinogen; human health criteria at risk level 10-5.

2.4

0.0043

0.09

0.0040

0.0080

0.0081

Chloride (μg/l)
16887006

Human Health health criterion to maintain acceptable taste and aesthetic quality and applies at the drinking water intake.

Chloride criteria do not apply in Class II transition zones (see subsection C of this section).

860,000

230,000

 

 

250,000

 

Chlorine, Total Residual (μg/l)
7782505

In DGIF class i and ii trout waters (9VAC25-260-390 through 9VAC25-260-540) or waters with threatened or endangered species are subject to the halogen ban (9VAC25-260-110).

19

See 9VAC25-260-110

11

See 9VAC25-260-110

 

 

 

 

Chlorine Produced Oxidant (μg/l)
7782505

 

 

13

7.5

 

 

Chlorobenzene (μg/l)
108907

 

 

 

 

130

1,600

Chlorodibromomethane (μg/l)
124481

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

4.0

130

Chloroform (μg/l)
67663

 

 

 

 

340

11,000

2-Chloronaphthalene (μg/l)
91587

 

 

 

 

1,000

1,600

2-Chlorophenol (μg/l)
95578

 

 

 

 

81

150

Chlorpyrifos (μg/l)
2921882

0.083

0.041

0.011

0.0056

 

 

Chromium III (μg/l)5
16065831

Freshwater values are a function of total hardness as calcium carbonate CaCO3 mg/l and the WER. The minimum hardness allowed for use in the equation below shall be 25 and the maximum hardness shall be 400 even when the actual ambient hardness is less than 25 or greater than 400.

Freshwater acute criterion μg/l

WER [e{0.8190[In(hardness)]+3.7256}] (CFa)

Freshwater chronic criterion μg/l
WER [e{0.8190[In(hardness)]+0.6848}] (CFc)

WER = Water Effect Ratio = 1 unless determined otherwise under 9VAC25-260-140.F

e = natural antilogarithm

ln = natural logarithm

CF = conversion factor a (acute) or c (chronic)

CFa= 0.316

CFc=0.860

570
(CaCO3 = 100)

74
(CaCO3 = 100)

 

 

100
(total Cr)

 

Chromium VI (μg/l)5
18540299

16

11

1,100

50

 

 

Chrysene (μg/l)
218019

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.0038 0.038

0.018

Copper (μg/l)5
7440508

Freshwater values are a function of total hardness as calcium carbonate CaCO3 mg/l and the WER. The minimum hardness allowed for use in the equation below shall be 25 and the maximum hardness shall be 400 even when the actual ambient hardness is less than 25 or greater than 400.

Freshwater acute criterion (μg/l)

WER [e {0.9422[In(hardness)]-1.700}] (CFa)

Freshwater chronic criterion (μg/l)
WER [e {0.8545[In(hardness)]-1.702}] (CFc)

WER = Water Effect Ratio = 1 unless determined otherwise under 9VAC25-260-140 F.

e = natural antilogarithm

ln = natural logarithm

CF = conversion factor a (acute) or c (chronic)

CFa = 0.960

CFc = 0.960

Alternate copper criteria in freshwater: the freshwater criteria for copper can also be calculated using the EPA 2007 Biotic Ligand Model (See 9VAC25-260-140 G ).

Acute saltwater criterion is a 24-hour average not to be exceeded more than once every three years on the average.

13
CaCO 3 = 100

9.0
CaCO3 = 100

9.3
X WER

6.0
X WER

1,300

 

Cyanide, Free (μg/l)
57125

22

5.2

1.0

1.0

[ 140 4.2 ]

[ 16,000 480 ]

DDD (μg/l)
72548

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.0031

0.0031

DDE (μg/l)
72559

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.0022

0.0022

DDT (μg/l)
50293

Known or suspected carcinogen; human health criteria at risk level 10-5.

Total concentration of DDT and metabolites shall not exceed aquatic life criteria.

1.1

0.0010

0.13

0.0010

0.0022

0.0022

Demeton (μg/l)
8065483

 

0.1

 

0.1

 

 

Diazinon (μg/l)
333415

0.17

0.17

0.82

0.82

 

 

Dibenz (a, h) anthracene (μg/l)
53703

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.038

0.18

1,2-Dichlorobenzene (μg/l)
95501

 

 

 

 

420

1,300

1,3-Dichlorobenzene (μg/l)
541731

 

 

 

 

320

960

1,4 Dichlorobenzene (μg/l)
106467

 

 

 

 

63

190

3,3 Dichlorobenzidine (μg/l)
91941

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.21

0.28

Dichlorobromomethane (μg/l)
75274

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

5.5

170

1,2 Dichloroethane (μg/l)
107062

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

3.8

370

1,1 Dichloroethylene (μg/l)
75354

 

 

 

 

330

7,100

1,2-trans-dichloroethylene (μg/l)
156605

 

 

 

 

140

10,000

2,4 Dichlorophenol (μg/l)
120832

 

 

 

 

77

290

2,4 Dichlorophenoxy acetic acid (2,4-D) (μg/l)
94757

 

 

 

 

100

 

1,2-Dichloropropane (μg/l)
78875

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

5.0

150

1,3-Dichloropropene (μg/l)
542756

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

3.4

210

Dieldrin (μg/l)
60571

Known or suspected carcinogen; human health criteria at risk level 10-5.

0.24

0.056

0.71

0.0019

0.00052

0.00054

Diethyl Phthalate (μg/l)
84662

 

 

 

 

17,000

44,000

2,4 Dimethylphenol (μg/l)
105679

 

 

 

 

380

850

Dimethyl Phthalate (μg/l)
131113

 

 

 

 

270,000

1,100,000

Di-n-Butyl Phthalate (μg/l)
84742

 

 

 

 

2,000

4,500

2,4 Dinitrophenol (μg/l)
51285

 

 

 

 

69

5,300

2-Methyl-4,6-Dinitrophenol (μg/l)
534521

 

 

 

 

13

280

2,4 Dinitrotoluene (μg/l)
121142

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

1.1

34

Dioxin 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (μg/l)
1746016

 

 

 

 

5.0 E-8

5.1 E-8

1,2-Diphenylhydrazine (μg/l)
122667

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.36

2.0

Dissolved Oxygen (μg/l)
(See 9VAC25-260-50)

 

 

 

 

 

 

Alpha-Endosulfan (μg/l)
959988

Total concentration alpha and beta-endosulfan shall not exceed aquatic life criteria.

0.22

0.056

0.034

0.0087

62

89

Beta-Endosulfan (μg/l)
33213659

Total concentration alpha and beta-endosulfan shall not exceed aquatic life criteria.

0.22

0.056

0.034

0.0087

62

89

Endosulfan Sulfate (μg/l)
1031078

 

 

 

 

62

89

Endrin (μg/l)
72208

0.086

0.036

0.037

0.0023

0.059

0.060

Endrin Aldehyde (μg/l)
7421934

 

 

 

 

0.29

0.30

Ethylbenzene (μg/l)
100414

 

 

 

 

530

2,100

Fecal Coliform
(see 9VAC25-260-160)

 

 

 

 

 

 

Fluoranthene (μg/l)
206440

 

 

 

 

130

140

Fluorene (μg/l)
86737

 

 

 

 

1,100

5,300

Foaming Agents (μg/l)
Criterion measured as methylene blue active substances. Criterion to maintain acceptable taste, odor, or aesthetic quality of drinking water and applies at the drinking water intake.

 

 

 

 

500

 

Guthion (μg/l)
86500

 

0.01

 

0.01

 

 

Heptachlor (μg/l)
76448

Known or suspected carcinogen; human health criteria at risk level 10-5.

0.52

0.0038

0.053

0.0036

0.00079

0.00079

Heptachlor Epoxide (μg/l)
1024573

Known or suspected carcinogen; human health criteria at risk level 10-5.

0.52

0.0038

0.053

0.0036

0.00039

0.00039

Hexachlorobenzene (μg/l)
118741

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.0028

0.0029

Hexachlorobutadiene (μg/l)
87683
Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

4.4

180

Hexachlorocyclohexane Alpha-BHC (μg/l)
319846

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.026

0.049

Hexachlorocyclohexane Beta-BHC (μg/l)
319857

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.091

0.17

Hexachlorocyclohexane (μg/l) (Lindane)

Gamma-BHC
58899

Known or suspected carcinogen; human health criteria at risk level 10-5.

0.95

 

0.16

 

0.98

1.8

Hexachlorocyclopentadiene (μg/l)
77474

 

 

 

 

40

1,100

Hexachloroethane (μg/l)
67721

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

[ 14 5.0 ]

[ 33 12 ]

Hydrogen sulfide (μg/l)
7783064

 

2.0

 

2.0

 

 

Indeno (1,2,3,-cd) pyrene (μg/l)
193395

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.038

0.18

Iron (μg/l)
7439896

Criterion to maintain acceptable taste, odor or aesthetic quality of drinking water and applies at the drinking water intake.

 

 

 

 

300

 

Isophorone (μg/l)
78591

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

350

9,600

Kepone (μg/l)
143500

 

zero

 

zero

 

 

Lead (μg/l)5
7439921

Freshwater values are a function of total hardness as calcium carbonate CaCO3 mg/l and the water effect ratio. The minimum hardness allowed for use in the equation below shall be 25 and the maximum hardness shall be 400 even when the actual ambient hardness is less than 25 or greater than 400.

Freshwater acute criterion (μg/l)
WER [e {1.273[In(hardness)]-1.084}](CFa)

Freshwater chronic criterion (μg/l)
WER [e {1.273[In(hardness)]-3.259}](CFc)

WER = Water Effect Ratio = 1 unless determined otherwise under 9VAC25-260-140 F

e = natural antilogarithm

ln = natural logarithm

CF = conversion factor a (acute) or c (chronic)

CFa = 1.46203-[(ln hardness)(0.145712)]

CFc = 1.46203-[(ln hardness)(0.145712)]

120 94
CaCO3 = 100

14 11
CaCO3 = 100

240 230 ] X WER

9.3 8.8 ] X WER

15

 

Malathion (μg/l)
121755

 

0.1

 

0.1

 

 

Manganese (μg/l)
7439965

Criterion to maintain acceptable taste, odor or aesthetic quality of drinking water and applies at the drinking water intake.

 

 

 

 

50

 

Mercury (μg/l) 5
7439976

1.4

0.77

1.8

0.94

 

 

Methyl Bromide (μg/l)
74839

 

 

 

 

47

1,500

Methyl Mercury (Fish Tissue Criterion mg/kg) 8
22967926

 

 

 

 

0.30

0.30

Methylene Chloride (μg/l)
75092

Known or suspected carcinogen; human health criteria at risk level 10-5. Synonym = Dichloromethane

 

 

 

 

[ 46 170 ]

[ 5,900 22,000 ]

Methoxychlor (μg/l)
72435

 

0.03

 

0.03

100

 

Mirex (μg/l)
2385855

 

zero

 

zero

 

 

Nickel (μg/l)5
744002

Freshwater values are a function of total hardness as calcium carbonate CaCO3 mg/l and the WER. The minimum hardness allowed for use in the equation below shall be 25 and the maximum hardness shall be 400 even when the actual ambient hardness is less than 25 or greater than 400.

Freshwater acute criterion (μg/l)
WER [e {0.8460[In(hardness)] + 1.312}] (CFa)

Freshwater chronic criterion (μg/l)
WER [e {0.8460[In(hardness)] - 0.8840}] (CFc)

WER = Water Effect Ratio = 1 unless determined otherwise under 9VAC25-260-140 F

e = natural antilogarithm

ln = natural logarithm

CF = conversion factor a (acute) or c (chronic)

CFa = 0.998

CFc = 0.997

180
CaCO3 = 100

20
CaCO3 = 100

74 X WER

8.2 X WER

610

4,600

Nitrate as N (μg/l)
14797558

 

 

 

 

10,000

 

Nitrobenzene (μg/l)
98953

 

 

 

 

[ 17 68 ]

[ 690 2,800 ]

N-Nitrosodimethylamine (μg/l)
62759

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.0069

30

N-Nitrosodiphenylamine (μg/l)
86306

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

33

160 60

N-Nitrosodi-n-propylamine (μg/l)
621647

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.050

5.1

Nonylphenol (μg/l)
1044051 84852153

28

6.6

7.0

1.7

 

 

Parathion (μg/l)
56382

0.065

0.013

 

 

 

 

PCB Total (μg/l)
1336363

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

0.014

 

0.030

0.00064

0.00064

Pentachlorophenol (μg/l)
87865

Known or suspected carcinogen; human health criteria risk level at 10-5.

Freshwater acute criterion (μg/l)
e (1.005(pH)-4.869)

Freshwater chronic criterion (μg/l)
e (1.005(pH)-5.134)

8.7
pH = 7.0

6.7
pH = 7.0

13

7.9

[ 2.7 0.80 ]

[ 30 9.1 ]

pH
See 9VAC25-260-50

 

 

 

 

 

 

Phenol (μg/l)
108952

 

 

 

 

10,000

860,000

Phosphorus Elemental (μg/l)
7723140

 

 

 

0.10

 

 

Pyrene (μg/l)
129000

 

 

 

 

830

4,000

Radionuclides

 

 

 

 

 

 

Gross Alpha Particle Activity (pCi/L)

 

 

 

 

15

 

Beta Particle & Photon Activity (mrem/yr) (formerly man-made radionuclides)

 

 

 

 

4

 

Combined Radium 226 and 228 (pCi/L)

 

 

 

 

5

 

Uranium (μg/L)

 

 

 

 

30

 

Selenium (μg/l)5
7782492

WER shall not be used for freshwater acute and chronic criteria. Freshwater criteria expressed as total recoverable.

20

5.0

290 X WER

71
X WER

170

4,200

Silver (μg/l)5
7440224

Freshwater values are a function of total hardness as calcium carbonate (CaCO3) mg/l and the WER. The minimum hardness allowed for use in the equation below shall be 25 and the maximum hardness shall be 400 even when the actual ambient hardness is less than 25 or greater than 400.

Freshwater acute criterion (μg/l)
WER [e {1.72[In(hardness)]-6.52}] (CFa)

WER = Water Effect Ratio = 1 unless determined otherwise under 9VAC25-260-140 F

e = natural antilogarithm

ln = natural logarithm

CF = conversion factor a (acute) or c (chronic)

CFa = 0.85

3.4; CaCO3 = 100

 

1.9 X WER

 

 

 

Sulfate (μg/l)

Criterion to maintain acceptable taste, odor or aesthetic quality of drinking water and applies at the drinking water intake.

 

 

 

 

250,000

 

Temperature

See 9VAC25-260-50

 

 

 

 

 

 

1,1,2,2-Tetrachloroethane (μg/l)
79345

Known or suspected carcinogen; human health criteria at risk level 10-5).

 

 

 

 

1.7

40

Tetrachloroethylene (μg/l)
127184

Known or suspected carcinogen; human health criteria at risk level 10-5).

 

 

 

 

[ 6.9 130 ]

[ 33 620 ]

Thallium (μg/l)
7440280

 

 

 

 

0.24

0.47

Toluene (μg/l)
108883

 

 

 

 

510

6,000

Total Dissolved Solids (μg/l)
Criterion to maintain acceptable taste, odor or aesthetic quality of drinking water and applies at the drinking water intake.

 

 

 

 

500,000

 

Toxaphene (μg/l)
8001352

Known or suspected carcinogen; human health criteria at risk level 10-5.

0.73

0.0002

0.21

0.0002

0.0028

0.0028

Tributyltin (μg/l)
60105

0.46

0.072

0.42

0.0074

 

 

1, 2, 4 Trichlorobenzene (μg/l)
120821

 

 

 

 

35

70

1,1,2-Trichloroethane (μg/l)
79005

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

5.9

160

Trichloroethylene (μg/l)
79016

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

[ 25 7.0 ]

[ 300 82 ]

2, 4, 6-Trichlorophenol (μg/l)
88062

Known or suspected carcinogen; human health criteria at risk level 10-5..

 

 

 

 

14

24

2-(2, 4, 5-Trichlorophenoxy) propionic acid (Silvex) (μg/l)
93721

 

 

 

 

50

 

Vinyl Chloride (μg/l)
75014

Known or suspected carcinogen; human health criteria at risk level 10-5.

 

 

 

 

0.25

24

Zinc (μg/l)5
7440666

Freshwater values are a function of total hardness as calcium carbonate (CaCO3) mg/l and the WER. The minimum hardness allowed for use in the equation below shall be 25 and the maximum, hardness shall be 400 even when the actual ambient hardness is less than 25 or greater than 400.

Freshwater acute criterion (μg/l)
WER [e {0.8473[In(hardness)]+0.884}] (CFa)

Freshwater chronic criterion (μg/l)
WER [e{0.8473[In(hardness)]+0.884}] (CFc)

WER = Water Effect Ratio = 1 unless determined otherwise under 9VAC25-260-140 F

e = base e exponential function. natural antilogarithm

ln = log normal function natural logarithm

CF = conversion factor a (acute) or c (chronic)

CFa = 0.978

CFc = 0.986

120 CaCO3 = 100

120 CaCO3 = 100

90
X WER

81
X WER

7,400

26,000

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 through 9VAC25-260-540.

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  through 9VAC25-260-540.

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.

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

Aquatic Life:

Acute criteria

1Q10

Chronic criteria

7Q10

Chronic criteria (ammonia)

30Q10

Human Health:

Noncarcinogens

30Q5

Carcinogens

Harmonic mean

The following are defined for this section:

"1Q10" means the lowest flow averaged over a period of one 1 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 7 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 5 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 and 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:

CLASS OF WATERS

NUMERICAL CRITERIA

I and II (Estuarine Waters)

Saltwater criteria apply

II (Transition Zone)

More stringent of either the freshwater or saltwater criteria apply

II (Tidal Freshwater), III, IV, V, VI and VII

Freshwater criteria apply

The following 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 the upstream boundary of the transition zone including all tidal tributaries that enter the tidal freshwater Rappahannock River.

Transition zone upstream boundary – N38° 4' 56.59"/-W76° 58' 47.93" (430 feet east of Hutchinson Swamp) to N38° 5' 23.33"/-W76° 58' 24.39" (0.7 miles upstream of Peedee Creek).

Transition zone downstream boundary – N37° 58' 45.80"/-W76° 55' 28.75" (1,000 feet downstream of Jenkins Landing) to N37° 59' 20.07/-W76° 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 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 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 the upstream boundary of the Pamunkey River transition zone, including all tidal tributaries that enter the tidal freshwaters of the Mattaponi and Pamunkey Rivers.

Mattaponni Mattaponi River transition zone upstream boundary – 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"/W76° 48' 38.22" (old Eltham Bridge, west side) to N37° 32' 6.25"/W76° 48' 18.82" (old Eltham Bridge, east side).

All tidal tributaries that enter the transition zones of the Mattaponi and Pamunkey Rivers are themselves in the transition zone.

Estuarine waters are from 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 freshwater is from the fall line of the James River in the City of Richmond upstream of Mayo Bridge to the upstream boundary of the transition zone, including all tidal tributaries that enter the tidal freshwater James River.

James River transition zone 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 miles 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 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 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 the upstream transition zone boundary near Quantico, Virginia.

Transition zone includes all tidal tributaries that enter the Potomac River from N38° 31' 27.05"/W77° 17' 7.06" (midway between Shipping Point and Quantico Pier) to 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 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 in subdivisions 1 through 4 of this subsection.

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. 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 (§ 2.2-4000 et seq. of the Code of Virginia). 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 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 U.S. Environmental Protection Agency for review and approval/ or 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 = equals 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 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, Part IV (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.

G. Biotic Ligand Model for copper. On a case-by-case basis, EPA's 2007 copper criteria (EPA-822-F-07-001) biotic ligand model (BLM) for copper may be used to determine alternate copper criteria for freshwater sites. The BLM is a bioavailability model that uses receiving water characteristics to develop site-specific criteria. Site-specific data for 10 parameters are needed to use the BLM. These parameters are temperature, pH, dissolved organic carbon, calcium, magnesium, sodium, potassium, sulfate, chloride, and alkalinity. If sufficient data for these parameters are available, the BLM can be used to calculate alternate criteria values for the copper criteria. The BLM would be used instead of the hardness-based criteria and takes the place of the hardness adjustment and the WER. A WER will not be applicable with the BLM.

9VAC25-260-155

9VAC25-260-155. Ammonia surface water quality criteria.

 [ A. The Department of Environmental Quality, after consultation with the Virginia Department of Game and Inland Fisheries and the U.S. Fish and Wildlife Service, has determined that the majority of Virginia freshwaters are likely to contain, or have contained in the past, freshwater mussel species in the family Unionidae and contain early life stages of fish during most times of the year. Therefore, the ammonia criteria presented in subsections B and C of this section are designed to provide protection to these species and life stages. In an instance where it can be adequately demonstrated that either freshwater mussels or early life stages of fish are not present in a specific waterbody, potential options for alternate, site-specific criteria are presented in subsection D of this section. Acute criteria are a one-hour average concentration not to be exceeded more than once every three years1 on the average, and chronic criteria are 30-day average concentrations not to be exceeded more than once every three years on the average2. ]

 [ A. B. ] The [ one-hour average concentration of total ammonia nitrogen (in mg N/L) in freshwater shall not exceed, more than once every three years on the average1, the ] acute criteria [ for total ammonia (in mg N/L) for freshwaters with trout absent or present are ] below:

[ Acute Ammonia Freshwater Criteria
Total Ammonia Nitrogen (mg N/L)

pH

Trout Present

Trout Absent

6.5

32.6

48.8

6.6

31.3

46.8

6.7

29.8

44.6

6.8

28.1

42.0

6.9

26.2

39.1

7.0

24.1

36.1

7.1

22.0

32.8

7.2

19.7

29.5

7.3

17.5

26.2

7.4

15.4

23.0

7.5

13.3

19.9

7.6

11.4

17.0

7.7

9.65

14.4

7.8

8.11

12.1

7.9

6.77

10.1

8.0

5.62

8.40

8.1

4.64

6.95

8.2

3.83

5.72

8.3

3.15

4.71

8.4

2.59

3.88

8.5

2.14

3.20

8.6

1.77

2.65

8.7

1.47

2.20

8.8

1.23

1.84

8.9

1.04

1.56

9.0

0.885

1.32

 

Acute Ammonia Freshwater Criteria
Total Ammonia Nitrogen (mg N/L)

TROUT ABSENT

Temperature (°C)

pH

0-10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

6.5

51

48

44

41

37

34

32

29

27

25

23

21

19

18

16

15

14

13

12

11

9.9

6.6

49

46

42

39

36

33

30

28

26

24

22

20

18

17

16

14

13

12

11

10

9.5

6.7

46

44

40

37

34

31

29

27

24

22

21

19

18

16

15

14

13

12

11

9.8

9.0

6.8

44

41

38

35

32

30

27

25

23

21

20

18

17

15

14

13

12

11

10

9.2

8.5

6.9

41

38

35

32

30

28

25

23

21

20

18

17

15

14

13

12

11

10

9.4

8.6

7.9

7.0

38

35

33

30

28

25

23

21

20

18

17

15

14

13

12

11

10

9.4

8.6

7.9

7.3

7.1

34

32

30

27

25

23

21

20

18

17

15

14

13

12

11

10

9.3

8.5

7.9

7.2

6.7

7.2

31

29

27

25

23

21

19

18

16

15

14

13

12

11

9.8

9.1

8.3

7.7

7.1

6.5

6.0

7.3

27

26

24

22

20

18

17

16

14

13

12

11

10

9.5

8.7

8.0

7.4

6.8

6.3

5.8

5.3

7.4

24

22

21

19

18

16

15

14

13

12

11

9.8

9.0

8.3

7.7

7.0

6.5

6.0

5.5

5.1

4.7

7.5

21

19

18

17

15

14

13

12

11

10

9.2

8.5

7.8

7.2

6.6

6.1

5.6

5.2

4.8

4.4

4.0

7.6

18

17

15

14

13

12

11

10

9.3

8.6

7.9

7.3

6.7

6.2

5.7

5.2

4.8

4.4

4.1

3.8

3.5

7.7

15

14

13

12

11

10

9.3

8.6

7.9

7.3

6.7

6.2

5.7

5.2

4.8

4.4

4.1

3.8

3.5

3.2

2.9

7.8

13

12

11

10

9.3

8.5

7.9

7.2

6.7

6.1

5.6

5.2

4.8

4.4

4.0

3.7

3.4

3.2

2.9

2.7

2.5

7.9

11

9.9

9.1

8.4

7.7

7.1

6.6

3.0

5.6

5.1

4.7

4.3

4.0

3.7

3.4

3.1

2.9

2.6

2.4

2.2

2.1

8.0

8.8

8.2

7.6

7.0

6.4

5.9

5.4

5.0

4.6

4.2

3.9

3.6

3.3

3.0

2.8

2.6

2.4

2.2

2.0

1.9

1.7

8.1

7.2

6.8

6.3

5.8

5.3

4.9

4.5

4.1

3.8

3.5

3.2

3.0

2.7

2.5

2.3

2.1

2.0

1.8

1.7

1.5

1.4

8.2

6.0

5.6

5.2

4.8

4.4

4.0

3.7

3.4

3.1

2.9

2.7

2.4

2.3

2.1

1.9

1.8

1.6

1.5

1.4

1.3

1.2

8.3

4.9

4.6

4.3

3.9

3.6

3.3

3.1

2.8

2.6

2.4

2.2

2.0

1.9

1.7

1.6

1.4

1.3

1.2

1.1

1.0

0.96

8.4

4.1

3.8

3.5

3.2

3.0

2.7

2.5

2.3

2.1

2.0

1.8

1.7

1.5

1.4

1.3

1.2

1.1

1.0

0.93

0.86

0.79

8.5

3.3

3.1

2.9

2.7

2.4

2.3

2.1

1.9

1.8

1.6

1.5

1.4

1.3

1.2

1.1

0.98

0.90

0.83

0.77

0.71

0.65

8.6

2.8

2.6

2.4

2.2

2.0

1.9

1.7

1.6

1.5

1.3

1.2

1.1

1.0

0.96

0.88

0.81

0.75

0.69

0.63

0.58

0.54

8.7

2.3

2.2

2.0

1.8

1.7

1.6

1.4

1.3

1.2

1.1

1.0

0.94

0.87

0.80

0.74

0.68

0.62

0.57

0.53

0.49

0.45

8.8

1.9

1.8

1.7

1.5

1.4

1.3

1.2

1.1

1.0

0.93

0.86

0.79

0.73

0.67

0.62

0.57

0.52

0.48

0.44

0.41

0.37

8.9

1.6

1.5

1.4

1.3

1.2

1.1

1.0

0.93

0.85

0.79

0.72

0.67

0.61

0.56

0.52

0.48

0.44

0.40

0.37

0.34

0.32

9.0

1.4

1.3

1.2

1.1

1.0

0.93

0.86

0.79

0.73

0.67

0.62

0.57

0.52

0.48

0.44

0.41

0.37

0.34

0.32

0.29

0.27 ]

 

Acute Ammonia Freshwater Criteria
Total Ammonia Nitrogen (mg N/L)

TROUT PRESENT

Temperature (°C)

pH

0-14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

6.5

33

33

32

29

27

25

23

21

19

18

16

15

14

13

12

11

9.9

6.6

31

31

30

28

26

24

22

20

18

17

16

14

13

12

11

10

9.5

6.7

30

30

29

27

24

22

21

19

18

16

15

14

13

12

11

9.8

9.0

6.8

28

28

27

25

23

21

20

18

17

15

14

13

12

11

10

9.2

8.5

6.9

26

26

25

23

21

20

18

17

15

14

13

12

11

10

9.4

8.6

7.9

7.0

24

24

23

21

20

18

17

15

14

13

12

11

10

9.4

8.6

8.0

7.3

7.1

22

22

21

20

18

17

15

14

13

12

11

10

9.3

8.5

7.9

7.2

6.7

7.2

20

20

19

18

16

15

14

13

12

11

9.8

9.1

8.3

7.7

7.1

6.5

6.0

7.3

18

18

17

16

14

13

12

11

10

9.5

8.7

8.0

7.4

6.8

6.3

5.8

5.3

7.4

15

15

15

14

13

12

11

9.8

9.0

8.3

7.7

7.0

6.5

6.0

5.5

5.1

4.7

7.5

13

13

13

12

11

10

9.2

8.5

7.8

7.2

6.6

6.1

5.6

5.2

4.8

4.4

4.0

7.6

11

11

11

10

9.3

8.6

7.9

7.3

6.7

6.2

5.7

5.2

4.8

4.4

4.1

3.8

3.5

7.7

9.6

9.6

9.3

8.6

7.9

7.3

6.7

6.2

5.7

5.2

4.8

4.4

4.1

3.8

3.5

3.2

3.0

7.8

8.1

8.1

7.9

7.2

6.7

6.1

5.6

5.2

4.8

4.4

4.0

3.7

3.4

3.2

2.9

2.7

2.5

7.9

6.8

6.8

6.6

6.0

5.6

5.1

4.7

4.3

4.0

3.7

3.4

3.1

2.9

2.6

2.4

2.2

2.1

8.0

5.6

5.6

5.4

5.0

4.6

4.2

3.9

3.6

3.3

3.0

2.8

2.6

2.4

2.2

2.0

1.9

1.7

8.1

4.6

4.6

4.5

4.1

3.8

3.5

3.2

3.0

2.7

2.5

2.3

2.1

2.0

1.8

1.7

1.5

1.4

8.2

3.8

3.8

3.7

3.5

3.1

2.9

2.7

2.4

2.3

2.1

1.9

1.8

1.6

1.5

1.4

1.3

1.2

8.3

3.1

3.1

3.1

2.8

2.6

2.4

2.2

2.0

1.9

1.7

1.6

1.4

1.3

1.2

1.1

1.0

0.96

8.4

2.6

2.6

2.5

2.3

2.1

2.0

1.8

1.7

1.5

1.4

1.3

1.2

1.1

1.0

0.93

0.86

0.79

8.5

2.1

2.1

2.1

1.9

1.8

1.6

1.5

1.4

1.3

1.2

1.1

0.98

0.90

0.83

0.77

0.71

0.65

8.6

1.8

1.8

1.7

1.6

1.5

1.3

1.2

1.1

1.0

0.96

0.88

0.81

0.75

0.69

0.63

0.59

0.54

8.7

1.5

1.5

1.4

1.3

1.2

1.1

1.0

0.94

0.87

0.80

0.74

0.68

0.62

0.57

0.53

0.49

0.45

8.8

1.2

1.2

1.2

1.1

1.0

0.93

0.86

0.79

0.73

0.67

0.62

0.57

0.52

0.48

0.44

0.41

0.37

8.9

1.0

1.0

1.0

0.93

0.85

0.79

0.72

0.67

0.61

0.56

0.52

0.48

0.44

0.40

0.37

0.34

0.32

9.0

0.88

0.88

0.86

0.79

0.73

0.67

0.62

0.57

0.52

0.48

0.44

0.41

0.37

0.34

0.32

0.29

0.27 ]  

The acute criteria for trout present shall apply to all Class V-Stockable Trout Waters and Class VI-Natural Trout Waters as listed in 9VAC25-260-390 through 9VAC25-260-540. [ The acute criteria for trout absent apply to all other fresh waters. ]

To calculate total ammonia nitrogen acute criteria values in freshwater at different pH values than those listed in this subsection, use the following [ formulas equations and round the result to two significant digits ]:

Where trout are [ present absent ]:

Acute Criterion Concentration (mg N/L) =

[ 0.275

+

39.0

 

(1 + 107.204-pH)

(1 + 10pH-7.204)

 

0.7249 X (


0.0114

+


1.6181

) X MIN

1 + 107.204-pH

1 + 10pH-7.204

Where MIN = 51.93 or 23.12 X 100.036 X (20 – T), whichever is less.

T = Temperature in oC ]

Or where trout are [ absent present, whichever of the below calculation results is less ]:

Acute Criterion Concentration (mg N/L) =

[ 0.411

+

58.4

(1 + 107.204-pH)

(1 + 10pH-7.204)

 

(

0.275

+

39.0

)

1 + 107.204-pH

1 + 10pH-7.204

Or

0.7249 X (

0.0114

+

1.6181

) X (23.12 X 100.036X(20 – T))

1 + 107.204-pH

1 + 10pH-7.204

T = Temperature in oC ]

[ 1The default design flow for calculating steady state waste load allocations for the acute ammonia criterion is the 1Q10 (see 9VAC25-260-140 B footnote 10) unless statistically valid methods are employed which demonstrate compliance with the duration and return frequency of the water quality criteria.

B. C. ] The [ 30-day average concentration of chronic criteria for ] total ammonia nitrogen (in mg N/L) where [ freshwater mussels and ] early life stages of fish are present in freshwater [ shall not exceed, more than once every three years on the average2, the chronic criteria are ] below:

[ Chronic Ammonia Freshwater Criteria
Early Life Stages of Fish Present
Total Ammonia Nitrogen (mg N/L)

 

Temperature (°C)

pH

0

14

16

18

20

22

24

26

28

30

6.5

6.67

6.67

6.06

5.33

4.68

4.12

3.62

3.18

2.80

2.46

6.6

6.57

6.57

5.97

5.25

4.61

4.05

3.56

3.13

2.75

2.42

6.7

6.44

6.44

5.86

5.15

4.52

3.98

3.50

3.07

2.70

2.37

6.8

6.29

6.29

5.72

5.03

4.42

3.89

3.42

3.00

2.64

2.32

6.9

6.12

6.12

5.56

4.89

4.30

3.78

3.32

2.92

2.57

2.25

7.0

5.91

5.91

5.37

4.72

4.15

3.65

3.21

2.82

2.48

2.18

7.1

5.67

5.67

5.15

4.53

3.98

3.50

3.08

2.70

2.38

2.09

7.2

5.39

5.39

4.90

4.31

3.78

3.33

2.92

2.57

2.26

1.99

7.3

5.08

5.08

4.61

4.06

3.57

3.13

2.76

2.42

2.13

1.87

7.4

4.73

4.73

4.30

3.78

3.32

2.92

2.57

2.26

1.98

1.74

7.5

4.36

4.36

3.97

3.49

3.06

2.69

2.37

2.08

1.83

1.61

7.6

3.98

3.98

3.61

3.18

2.79

2.45

2.16

1.90

1.67

1.47

7.7

3.58

3.58

3.25

2.86

2.51

2.21

1.94

1.71

1.50

1.32

7.8

3.18

3.18

2.89

2.54

2.23

1.96

1.73

1.52

1.33

1.17

7.9

2.80

2.80

2.54

2.24

1.96

1.73

1.52

1.33

1.17

1.03

8.0

2.43

2.43

2.21

1.94

1.71

1.50

1.32

1.16

1.02

0.897

8.1

2.10

2.10

1.91

1.68

1.47

1.29

1.14

1.00

0.879

0.773

8.2

1.79

1.79

1.63

1.43

1.26

1.11

0.973

0.855

0.752

0.661

8.3

1.52

1.52

1.39

1.22

1.07

0.941

0.827

0.727

0.639

0.562

8.4

1.29

1.29

1.17

1.03

0.906

0.796

0.700

0.615

0.541

0.475

8.5

1.09

1.09

0.990

0.870

0.765

0.672

0.591

0.520

0.457

0.401

8.6

0.920

0.920

0.836

0.735

0.646

0.568

0.499

0.439

0.386

0.339

8.7

0.778

0.778

0.707

0.622

0.547

0.480

0.422

0.371

0.326

0.287

8.8

0.661

0.661

0.601

0.528

0.464

0.408

0.359

0.315

0.277

0.244

8.9

0.565

0.565

0.513

0.451

0.397

0.349

0.306

0.269

0.237

0.208

9.0

0.486

0.486

0.442

0.389

0.342

0.300

0.264

0.232

0.204

0.179

 

Chronic Ammonia Freshwater Criteria
Mussels and Early Life Stages of Fish Present

Total Ammonia Nitrogen (mg N/L)

Temperature (°C)

pH

0-7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

6.5

4.9

4.6

4.3

4.1

3.8

3.6

3.3

3.1

2.9

2.8

2.6

2.4

2.3

2.1

2.0

1.9

1.8

1.6

1.5

1.5

1.4

1.3

1.2

1.1

6.6

4.8

4.5

4.3

4.0

3.8

3.5

3.3

3.1

2.9

2.7

2.5

2.4

2.2

2.1

2.0

1.8

1.7

1.6

1.5

1.4

1.3

1.3

1.2

1.1

6.7

4.8

4.5

4.2

3.9

3.7

3.5

3.2

3.0

2.8

2.7

2.5

2.3

2.2

2.1

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.2

1.1

6.8

4.6

4.4

4.1

3.8

3.6

3.4

3.2

3.0

2.8

2.6

2.4

2.3

2.1

2.0

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.1

6.9

4.5

4.2

4.0

3.7

3.5

3.3

3.1

2.9

2.7

2.5

2.4

2.2

2.1

2.0

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.2

1.1

1.0

7.0

4.4

4.1

3.8

3.6

3.4

3.2

3.0

2.8

2.6

2.4

2.3

2.2

2.0

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.1

0.99

7.1

4.2

3.9

3.7

3.5

3.2

3.0

2.8

2.7

2.5

2.3

2.2

2.1

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.2

1.1

1.0

0.95

7.2

4.0

3.7

3.5

3.3

3.1

2.9

2.7

2.5

2.4

2.2

2.1

2.0

1.8

1.7

1.6

1.5

1.4

1.3

1.3

1.2

1.1

1.0

0.96

0.90

7.3

3.8

3.5

3.3

3.1

2.9

2.7

2.6

2.4

2.2

2.1

2.0

1.8

1.7

1.6

1.5

1.4

1.3

1.3

1.2

1.1

1.0

0.97

0.91

0.85

7.4

3.5

3.3

3.1

2.9

2.7

2.5

2.4

2.2

2.1

2.0

1.8

1.7

1.6

1.5

1.4

1.3

1.3

1.2

1.1

1.0

0.96

0.90

0.85

0.79

7.5

3.2

3.0

2.8

2.7

2.5

2.3

2.2

2.1

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.2

1.1

1.0

0.95

0.89

0.83

0.78

0.73

7.6

2.9

2.8

2.6

2.4

2.3

2.1

2.0

1.9

1.8

1.6

1.5

1.4

1.4

1.3

1.2

1.1

1.1

0.98

0.92

0.86

0.81

0.76

0.71

0.67

7.7

2.6

2.4

2.3

2.2

2.0

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.1

1.0

0.94

0.88

0.83

0.78

0.73

0.68

0.64

0.60

7.8

2.3

2.2

2.1

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.2

1.1

1.0

0.95

0.89

0.84

0.79

0.74

0.69

0.65

0.61

0.57

0.53

7.9

2.1

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.2

1.1

1.0

0.95

0.89

0.84

0.79

0.74

0.69

0.65

0.61

0.57

0.53

0.50

0.47

8.0

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

1.1

1.0

0.94

0.88

0.83

0.78

0.73

0.68

0.64

0.60

0.56

0.53

0.50

0.44

0.44

0.41

8.1

1.5

1.5

1.4

1.3

1.2

1.1

1.1

0.99

0.92

0.87

0.81

0.76

0.71

0.67

0.63

0.59

0.55

0.52

0.49

0.46

0.43

0.40

0.38

0.35

8.2

1.3

1.2

1.2

1.1

1.0

0.96

0.90

0.84

0.79

0.74

0.70

0.65

0.61

0.57

0.54

0.50

0.47

0.44

0.42

0.39

0.37

0.34

0.32

0.30

8.3

1.1

1.1

0.99

0.93

0.87

0.82

0.76

0.72

0.67

0.63

0.59

0.55

0.52

0.49

0.46

0.43

0.40

0.38

0.35

0.33

0.31

0.29

0.27

0.26

8.4

0.95

0.89

0.84

0.79

0.74

0.69

0.65

0.61

0.57

0.53

0.50

0.47

0.44

0.41

0.39

0.36

0.34

0.32

0.30

0.28

0.26

0.25

0.23

0.22

8.5

0.80

0.75

0.71

0.67

0.62

0.58

0.55

0.51

0.48

0.45

0.42

0.40

0.37

0.35

0.33

0.31

0.29

0.27

0.25

0.24

0.22

0.21

0.20

0.18

8.6

0.68

0.64

0.60

0.56

0.53

0.49

0.46

0.43

0.41

0.38

0.36

0.33

0.31

0.29

0.28

0.26

0.24

0.23

0.21

0.20

0.19

0.18

0.16

0.15

8.7

0.57

0.54

0.51

0.47

0.44

0.42

0.39

0.37

0.34

0.32

0.30

0.28

0.27

0.25

0.23

0.22

0.21

0.19

0.18

0.17

0.16

0.15

0.14

0.13

8.8

0.49

0.46

0.43

0.40

0.38

0.35

0.33

0.31

0.29

0.27

0.26

0.24

0.23

0.21

0.20

0.19

0.17

0.16

0.15

0.14

0.13

0.13

0.12

0.11

8.9

0.42

0.39

0.37

0.34

0.32

0.30

0.28

0.27

0.25

0.23

0.22

0.21

0.19

0.18

0.17

0.16

0.15

0.14

0.13

0.12

0.12

0.11

0.10

0.09

9.0

0.36

0.34

0.32

0.30

0.28

0.26

0.24

0.23

0.21

0.20

0.19

0.18

0.17

0.16

0.15

0.14

0.13

0.12

0.11

0.11

0.10

0.09

0.09

0.08 ]

To calculate total ammonia nitrogen chronic criteria values in freshwater when [ fish freshwater mussels and ] early life stages [ of fish ] are present at different pH and temperature values than those listed in this subsection, use the following [ formulas equation and round the result to two significant digits ]:

Chronic Criteria Concentration =

[ (

0.0577

+

2.487

 )

x MIN

(1 + 107.688-pH)

(1 + 10pH-7.688)

Where MIN = 2.85 or 1.45 x 100.028(25-T), whichever is less.

0.8876 X (

0.0278

+

1.1994

) X (2.126 X 100.028 X (20 - MAX(T,7)))

1 + 107.688-pH

1 + 10pH-7.688

Where MAX = 7 or temperature in degrees Celsius, whichever is greater. ]

T = temperature in °C

2The default design flow for calculating steady state waste load allocations for the chronic ammonia criterion where early life stages of fish are present is the 30Q10 (see 9VAC25-260-140 B footnote 10) unless statistically valid methods are employed which demonstrate compliance with the duration and return frequency of the water quality criteria.

D. Site-specific considerations and alternate criteria. If it can be adequately demonstrated that freshwater mussels or early life stages of fish are not present at a site, then alternate site-specific criteria can be considered using the information provided in this subsection. Recalculated site-specific criteria shall provide for the attainment and maintenance of the water quality standards of downstream waters.

1. Site-specific modifications to the ambient water quality criteria for ammonia to account for the absence of freshwater mussels or early life stages of fish shall be conducted in accordance with the procedures contained in this subdivision. Because the department presumes that most state waterbodies have freshwater mussels and early life stages of fish present during most times of the year, the criteria shall be calculated assuming freshwater mussels and early life stages of fish are present using subsections B and C of this section unless the following demonstration that freshwater mussels or early life stages of fish are absent is successfully completed. Determination of the absence of freshwater mussels requires special field survey methods. This determination must be made after an adequate survey of the waterbody is conducted by an individual certified by the Virginia Department of Game and Inland Fisheries (DGIF) for freshwater mussel identification and surveys. Determination of absence of freshwater mussels will be done in consultation with the DGIF. Early life stages of fish are defined in subdivision 2 of this subsection. Modifications to the ambient water quality criteria for ammonia based on the presence or absence of early life stages of fish shall only apply at temperatures below 15°C.

a. During the review of any new or existing activity that has a potential to discharge ammonia in amounts that may cause or contribute to a violation of the ammonia criteria contained in subsection B of this section, the department may examine data from the following approved sources in subdivisions 1 a (1) through (5) of this subsection or may require the gathering of data in accordance with subdivisions 1 a (1) through (5) on the presence or absence of early life stages of fish in the affected waterbody.

(1) Species and distribution data contained in the Virginia Department of Game and Inland Fisheries Wildlife Information System database.

(2) Species and distribution data contained in Freshwater Fishes of Virginia, 1994.

(3) Data and fish species distribution maps contained in Handbook for Fishery Biology, Volume 3, 1997.

(4) Field data collected in accordance with U.S. EPA's Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers, Second Edition, EPA 841-B-99-002. Field data must comply with all quality assurance and quality control criteria.

(5) The American Society for Testing and Materials (ASTM) Standard E-1241-88, Standard Guide for Conducting Early Life-Stage Toxicity Tests with Fishes.

b. If data or information from sources other than subdivisions 1 a (1) through (5) of this subsection are considered, then any resulting site-specific criteria modifications shall be reviewed and adopted in accordance with the site-specific criteria provisions in 9VAC25-260-140 D, and submitted to EPA for review and approval.

c. If the department determines that the data and information obtained from subdivisions 1 a (1) through (5) of this subsection demonstrate that there are periods of each year when no early life stages are expected to be present for any species of fish that occur at the site, the department shall issue a notice to the public and make available for public comment the supporting data and analysis along with the department's preliminary decision to authorize the site-specific modification to the ammonia criteria. Such information shall include, at a minimum:

(1) Sources of data and information.

(2) List of fish species that occur at the site as defined in subdivision 3 of this subsection.

(3) Definition of the site. Definition of a "site" can vary in geographic size from a stream segment to a watershed to an entire eco-region.

(4) Duration of early life stage for each species in subdivision 1 c (2) of this subsection.

(5) Dates when early life stages of fish are expected to be present for each species in subdivision 1 c (2) of this subsection.

(6) Based on subdivision 1 c (5) of this subsection, identify the dates (beginning date, ending date), if any, where no early life stages are expected to be present for any of the species identified in subdivision 1 c (2) of this subsection.

d. If, after reviewing the public comments received in subdivision 1 c of this subsection and supporting data and information, the department determines that there are times of the year where no early life stages are expected to be present for any fish species that occur at the site, then the applicable ambient water quality criteria for ammonia for those time periods shall be calculated using the table in this subsection, or the formula for calculating the chronic criterion concentration for ammonia when early life stages of fish are absent.

e. The department shall maintain a comprehensive list of all sites where the department has determined that early life stages of fish are absent. For each site the list will identify the waterbodies affected and the corresponding times of the year that early life stages of fish are absent. This list is available either upon request from the Office of Water Quality Programs at 629 East Main Street, Richmond, VA 23219, or from the department website at http://www.deq.virginia.gov/programs/water/waterqualityinformationtmdls/waterqualitystandards.aspx.

2. The duration of the "early life stages" extends from the beginning of spawning through the end of the early life stages. The early life stages include the prehatch embryonic period, the post-hatch free embryo or yolk-sac fry, and the larval period, during which the organism feeds. Juvenile fish, which are anatomically similar to adults, are not considered an early life stage. The duration of early life stages can vary according to fish species. The department considers the sources of information in subdivisions 1 a (1) through (5) of this subsection to be the only acceptable sources of information for determining the duration of early life stages of fish under this procedure.

3. "Occur at the site" includes the species, genera, families, orders, classes, and phyla that are usually present at the site; are present at the site only seasonally due to migration; are present intermittently because they periodically return to or extend their ranges into the site; or were present at the site in the past or are present in nearby bodies of water, but are not currently present at the site due to degraded conditions, and are expected to return to the site when conditions improve. "Occur at the site" does not include taxa that were once present at the site but cannot exist at the site now due to permanent physical alteration of the habitat at the site.

4. Any modifications to ambient water quality criteria for ammonia in subdivision 1 of this subsection shall not likely jeopardize the continued existence of any federal or state listed, threatened, or endangered species or result in the destruction or adverse modification of such species' critical habitats.

5. Site-specific modifications to the ambient water quality criteria for ammonia to account for the absence of freshwater mussels shall be conducted in accordance with the procedures contained in this subdivision. Because the department presumes that most state waterbodies have freshwater mussel species, the criteria shall be calculated assuming mussels are present using subsections B and C of this section unless the demonstration that freshwater mussels are absent is successfully completed and accepted by DEQ and DGIF.

6. Equations for calculating ammonia criteria for four different site-specific scenarios are provided below as follows: (i) acute criteria when mussels are absent but trout are present, (ii) acute criteria when mussels and trout are absent, (iii) chronic criteria when mussels are absent and early life stages of fish are present, and (iv) chronic criteria when mussels and early life stages of fish are absent. Additional information regarding site-specific criteria can be reviewed in appendix N (pages 225-242) of the EPA Aquatic Life Ambient Water Quality Criteria to Ammonia--Freshwater 2013 (EPA 822-R-13-001).

a. Acute criteria: freshwater mussels absent and trout present.

To calculate total ammonia nitrogen acute criteria values (in mg N/L) in freshwater with freshwater mussels absent (procedures for making this determination are in subdivisions 1 through 5 of this subsection) and trout present, use the equations below. The acute criterion is the lesser of the calculation results below. Round the result to two significant digits.

 (

0.275

+

39

)

1 + 107.204-pH

1 + 10pH-7.204

Or

0.7249 X (

0.0114

+

1.6181

) X (62.15 X 100.036X(20 – T))

1 + 107.204-pH

1 + 10pH-7.204

b. Acute criteria: freshwater mussels absent and trout absent.

To calculate total ammonia nitrogen acute criteria values (in mg N/L) in freshwater where freshwater mussels are absent and trout are absent, use the following equation. Round the result to two significant digits.

0.7249 X (

0.0114

+

1.6181

) X MIN

1 + 107.204-pH

1 + 10pH-7.204

Where MIN = 51.93 or 62.15 X 100.036 X (20 – T), whichever is less.

T = Temperature in oC.

c. Chronic criteria: freshwater mussels absent and early life stages of fish present. ]

[ C. The 30-day average concentration of The chronic criteria for ] total ammonia nitrogen (in mg N/L) where [ early life stages of fish freshwater mussels ] are absent (procedures for making this determination are in subdivisions 1 through [ 4 5 ] of this subsection) in freshwater shall not exceed [ , more than once every three years on the average3, the chronic criteria concentration values calculated using the equation ] below [ :. Round the result to two significant digits. ]

[ Chronic Ammonia Freshwater Criteria
Early Life Stages of Fish Absent
Total Ammonia Nitrogen (mg N/L)

Temperature (°C)

pH

0-7

8

9

10

11

12

13

14

15

16

6.5

10.8

10.1

9.51

8.92

8.36

7.84

7.35

6.89

6.46

6.06

6.6

10.7

9.99

9.37

8.79

8.24

7.72

7.24

6.79

6.36

5.97

6.7

10.5

9.81

9.20

8.62

8.08

7.58

7.11

6.66

6.25

5.86

6.8

10.2

9.58

8.98

8.42

7.90

7.40

6.94

6.51

6.10

5.72

6.9

9.93

9.31

8.73

8.19

7.68

7.20

6.75

6.33

5.93

5.56

7.0

9.60

9.00

8.43

7.91

7.41

6.95

6.52

6.11

5.73

5.37

7.1

9.20

8.63

8.09

7.58

7.11

6.67

6.25

5.86

5.49

5.15

7.2

8.75

8.20

7.69

7.21

6.76

6.34

5.94

5.57

5.22

4.90

7.3

8.24

7.73

7.25

6.79

6.37

5.97

5.60

5.25

4.92

4.61

7.4

7.69

7.21

6.76

6.33

5.94

5.57

5.22

4.89

4.59

4.30

7.5

7.09

6.64

6.23

5.84

5.48

5.13

4.81

4.51

4.23

3.97

7.6

6.46

6.05

5.67

5.32

4.99

4.68

4.38

4.11

3.85

3.61

7.7

5.81

5.45

5.11

4.79

4.49

4.21

3.95

3.70

3.47

3.25

7.8

5.17

4.84

4.54

4.26

3.99

3.74

3.51

3.29

3.09

2.89

7.9

4.54

4.26

3.99

3.74

3.51

3.29

3.09

2.89

2.71

2.54

8.0

3.95

3.70

3.47

3.26

3.05

2.86

2.68

2.52

2.36

2.21

8.1

3.41

3.19

2.99

2.81

2.63

2.47

2.31

2.17

2.03

1.91

8.2

2.91

2.73

2.56

2.40

2.25

2.11

1.98

1.85

1.74

1.63

8.3

2.47

2.32

2.18

2.04

1.91

1.79

1.68

1.58

1.48

1.39

8.4

2.09

1.96

1.84

1.73

1.62

1.52

1.42

1.33

1.25

1.17

8.5

1.77

1.66

1.55

1.46

1.37

1.28

1.20

1.13

1.06

0.990

8.6

1.49

1.40

1.31

1.23

1.15

1.08

1.01

0.951

0.892

0.836

8.7

1.26

1.18

1.11

1.04

0.976

0.915

0.858

0.805

0.754

0.707

8.8

1.07

1.01

0.944

0.885

0.829

0.778

0.729

0.684

0.641

0.601

8.9

0.917

0.860

0.806

0.756

0.709

0.664

0.623

0.584

0.548

0.513

9.0

0.790

0.740

0.694

0.651

0.610

0.572

0.536

0.503

0.471

0.442

At 15°C and above, the criterion for fish early life stages absent is the same as the criterion for fish early life stages present.

To calculate total ammonia nitrogen chronic criteria values in freshwater when fish early life stages are absent at different pH and temperature values than those listed in this subsection, use the following formulas:

Chronic Criteria Concentration =

(

0.0577

+

2.487

)

x 1.45(100.028(25-MAX))

(1 + 107.688-pH)

(1 + 10pH-7.688)

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

0.9405 X (

0.0278

+

1.1994

) X MIN

1 + 107.688-pH

1 + 10pH-7.688

Where MIN = 6.920 or 7.547 X 100.028 x (20 – T) whichever is less

T = temperature in °C ]

3The default design flow for calculating steady state waste load allocations for the chronic ammonia criterion where early life stages of fish are absent is the 30Q10 (see 9VAC25-260-140 B footnote 10) unless statistically valid methods are employed that demonstrate compliance with the duration and return frequency of the water quality criteria.

1. Site-specific modifications to the ambient water quality criteria for ammonia to account for the absence of early life stages of fish shall be conducted in accordance with the procedures contained in this subdivision. Because the department presumes that most state waterbodies have early life stages of fish present during most times of the year, the criteria shall be calculated assuming early life stages of fish are present using subsection B of this section unless the following demonstration that early life stages are absent is successfully completed. Early life stages of fish are defined in subdivision 2 of this subsection. Modifications to the ambient water quality criteria for ammonia based on the presence or absence of early life stages of fish shall only apply at temperatures below 15°C.

a. During the review of any new or existing activity that has a potential to discharge ammonia in amounts that may cause or contribute to a violation of the ammonia criteria contained in subsection B of this section, the department may examine data from the following approved sources in subdivisions 1 a (1) through (5) of this subsection or may require the gathering of data in accordance with subdivisions 1 a (1) through (5) on the presence or absence of early life stages of fish in the affected waterbody.

(1) Species and distribution data contained in the Virginia Department of Game and Inland Fisheries Wildlife Information System database.

(2) Species and distribution data contained in Freshwater Fishes of Virginia, 1994.

(3) Data and fish species distribution maps contained in Handbook for Fishery Biology, Volume 3, 1997.

(4) Field data collected in accordance with U.S. EPA's Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers, Second Edition, EPA 841-B-99-002. Field data must comply with all quality assurance/quality control criteria.

(5) The American Society for Testing and Materials (ASTM) Standard E-1241-88, Standard Guide for Conducting Early Life-Stage Toxicity Tests with Fishes.

b. If data or information from sources other than subdivisions 1 a (1) through (5) of this subsection are considered, then any resulting site-specific criteria modifications shall be reviewed and adopted in accordance with the site-specific criteria provisions in 9VAC25-260-140 D, and submitted to EPA for review and approval.

c. If the department determines that the data and information obtained from subdivisions 1 a (1) through (5) of this subsection demonstrate that there are periods of each year when no early life stages are expected to be present for any species of fish that occur at the site, the department shall issue a notice to the public and make available for public comment the supporting data and analysis along with the department's preliminary decision to authorize the site-specific modification to the ammonia criteria. Such information shall include, at a minimum:

(1) Sources of data and information.

(2) List of fish species that occur at the site as defined by subdivision 3 of this subsection.

(3) Definition of the site. Definition of a "site" can vary in geographic size from a stream segment to a watershed to an entire eco-region.

(4) Duration of early life stage for each species in subdivision 1 c (2) of this subsection.

(5) Dates when early life stages of fish are expected to be present for each species in subdivision 1 c (2) of this subsection.

(6) Based on subdivision 1 c (5) of this subsection, identify the dates (beginning date, ending date), if any, where no early life stages are expected to be present for any of the species identified in subdivision 1 c (2) of this subsection.

d. If, after reviewing the public comments received in subdivision 1 c of this subsection and supporting data and information, the department determines that there are times of the year where no early life stages are expected to be present for any fish species that occur at the site, then the applicable ambient water quality criteria for ammonia for those time periods shall be calculated using the table in this subsection, or the formula for calculating the chronic criterion concentration for ammonia when fish early life stages are absent.

e. The department shall maintain a comprehensive list of all sites where the department has determined that early life stages of fish are absent. For each site the list will identify the waterbodies affected and the corresponding times of the year that early life stages are absent. This list is available either upon request from the Office of Water Quality Programs at P.O. Box 1105, Richmond, Virginia 23218 or from the department website http://www.deq.virginia.gov/wqs.

2. The duration of the "early life stages" extends from the beginning of spawning through the end of the early life stages. The early life stages include the prehatch embryonic period, the post-hatch free embryo or yolk-sac fry, and the larval period, during which the organism feeds. Juvenile fish, which are anatomically similar to adults, are not considered an early life stage. The duration of early life stages can vary according to fish species. The department considers the sources of information in subdivisions 1 a (1) through (5) of this subsection to be the only acceptable sources of information for determining the duration of early life stages of fish under this procedure.

3. "Occur at the site" includes the species, genera, families, orders, classes, and phyla that: are usually present at the site; are present at the site only seasonally due to migration; are present intermittently because they periodically return to or extend their ranges into the site; were present at the site in the past or are present in nearby bodies of water, but are not currently present at the site due to degraded conditions, and are expected to return to the site when conditions improve. "Occur at the site" does not include taxa that were once present at the site but cannot exist at the site now due to permanent physical alteration of the habitat at the site.

4. Any modifications to ambient water quality criteria for ammonia in subdivision 1 of this subsection shall not likely jeopardize the continued existence of any federal or state listed, threatened or endangered species or result in the destruction or adverse modification of such species' critical habitat.

d. Chronic criteria: freshwater mussels absent and early life stages of fish absent.

The chronic criteria for total ammonia nitrogen (in mg N/L) where freshwater mussels are absent and early life stages of fish are absent (procedures for making this determination are in subdivisions 1 through 5 of this subsection in freshwater shall not exceed concentration values calculated using the equation below. Round the result to two significant digits.

0.9405 X (

0.0278

+

1.1994

) X(7.547 X 100.028 X (20 - MAX(T,7)))

1 + 107.688-pH

1 + 10pH-7.688

Where MAX = 7 or temperature in degrees Celsius, whichever is greater.

T = temperature in °C ]

[ D. E. ] The one-hour average concentration of total ammonia nitrogen (in mg N/L) in saltwater shall not exceed, more than once every three years on the average, the acute criteria below:

Acute Ammonia Saltwater Criteria
Total Ammonia Nitrogen (mg N/L)
Salinity = 10 g/kg

 

Temperature °C

pH

0

5

10

15

20

25

30

35

7.00

231.9

159.8

110.1

75.88

52.31

36.08

24.91

17.21

7.20

146.4

100.9

69.54

47.95

33.08

22.84

15.79

10.93

7.40

92.45

63.73

43.94

30.32

20.94

14.48

10.03

6.97

7.60

58.40

40.28

27.80

19.20

13.28

9.21

6.40

4.47

7.80

36.92

25.48

17.61

12.19

8.45

5.88

4.11

2.89

8.00

23.37

16.15

11.18

7.76

5.40

3.78

2.66

1.89

8.20

14.81

10.26

7.13

4.97

3.48

2.46

1.75

1.27

8.40

9.42

6.54

4.57

3.20

2.27

1.62

1.18

0.87

8.60

6.01

4.20

2.95

2.09

1.50

1.09

0.81

0.62

8.80

3.86

2.72

1.93

1.39

1.02

0.76

0.58

0.46

9.00

2.51

1.79

1.29

0.95

0.71

0.55

0.44

0.36

Salinity = 20 g/kg

 

Temperature °C

pH

0

5

10

15

20

25

30

35

7.00

247.6

170.5

117.5

80.98

55.83

38.51

26.58

18.36

7.20

156.3

107.7

74.21

51.17

35.30

24.37

16.84

11.66

7.40

98.67

68.01

46.90

32.35

22.34

15.44

10.70

7.43

7.60

62.33

42.98

29.66

20.48

14.17

9.82

6.82

4.76

7.80

39.40

27.19

18.78

13.00

9.01

6.26

4.37

3.07

8.00

24.93

17.23

11.92

8.27

5.76

4.02

2.83

2.01

8.20

15.80

10.94

7.59

5.29

3.70

2.61

1.86

1.34

8.40

10.04

6.97

4.86

3.41

2.41

1.72

1.24

0.91

8.60

6.41

4.47

3.14

2.22

1.59

1.15

0.85

0.65

8.80

4.11

2.89

2.05

1.47

1.07

0.80

0.61

0.48

9.00

2.67

1.90

1.36

1.00

0.75

0.57

0.46

0.37

Salinity = 30 g/kg

 

Temperature °C

pH

0

5

10

15

20

25

30

35

7.00

264.6

182.3

125.6

86.55

59.66

41.15

28.39

19.61

7.20

167.0

115.1

79.31

54.68

37.71

26.03

17.99

12.45

7.40

105.5

72.68

50.11

34.57

23.87

16.50

11.42

7.92

7.60

66.61

45.93

31.69

21.88

15.13

10.48

7.28

5.07

7.80

42.10

29.05

20.07

13.88

9.62

6.68

4.66

3.27

8.00

26.63

18.40

12.73

8.83

6.14

4.29

3.01

2.13

8.20

16.88

11.68

8.10

5.64

3.94

2.78

1.97

1.42

8.40

10.72

7.44

5.18

3.63

2.56

1.82

1.31

0.96

8.60

6.83

4.77

3.34

2.36

1.69

1.22

0.90

0.68

8.80

4.38

3.08

2.18

1.56

1.13

0.84

0.64

0.50

9.00

2.84

2.01

1.45

1.06

0.79

0.60

0.47

0.39

To calculate total ammonia nitrogen acute criteria values in saltwater at different pH and temperature values than those listed in this subsection, use the following formulas:

I =

19.9273S

(1000 - 1.005109S)

Where I = molal ionic strength of water

S = Salinity ppt (g/kg)

The regression model used to relate I to pKa (negative log of the ionization constant) is

pKa = 9.245 + .138I 0.138(I)

pKa as defined by these equations is at 298 degrees Kelvin (25°C). T °Kelvin = °C + 273

To correct for other temperatures:

pKaST = pKaS298 + .0324(298 - T °Kelvin) 0.0324(298 - T °Kelvin)

The unionized ammonia fraction (UIA) is given by:

UIA =

1

1 + 10(pKaST-pH)

The acute ammonia criterion in saltwater is given by:

Acute =

.233 0.233

UIA

Multiply the acute value by .822 0.822 to get the ammonia-N acute criterion.

 [ E. F. ] The 30-day average concentration of total ammonia nitrogen (in mg N/L) in saltwater shall not exceed, more than once every three years on the average, the chronic criteria below:

Chronic Ammonia Saltwater Criteria
Total Ammonia Nitrogen (mg N/L)
Salinity = 10 g/kg

 

Temperature °C

pH

0

5

10

15

20

25

30

35

7.00

34.84

24.00

16.54

11.40

7.86

5.42

3.74

2.59

7.20

21.99

15.15

10.45

7.20

4.97

3.43

2.37

1.64

7.40

13.89

9.57

6.60

4.55

3.15

2.18

1.51

1.05

7.60

8.77

6.05

4.18

2.88

2.00

1.38

0.96

0.67

7.80

5.55

3.83

2.65

1.83

1.27

0.88

0.62

0.43

8.00

3.51

2.43

1.68

1.17

0.81

0.57

0.40

0.28

8.20

2.23

1.54

1.07

0.75

0.52

0.37

0.26

0.19

8.40

1.41

0.98

0.69

0.48

0.34

0.24

0.18

0.13

8.60

0.90

0.63

0.44

0.31

0.23

0.16

0.12

0.09

8.80

0.58

0.41

0.29

0.21

0.15

0.11

0.09

0.07

9.00

0.38

0.27

0.19

0.14

0.11

0.08

0.07

0.05

Salinity = 20 g/kg

 

 

Temperature °C

 

pH

0

5

10

15

20

25

30

35

 

7.00

37.19

25.62

17.65

12.16

8.39

5.78

3.99

2.76

 

7.20

23.47

16.17

11.15

7.69

5.30

3.66

2.53

1.75

 

7.40

14.82

10.22

7.04

4.86

3.36

2.32

1.61

1.12

 

7.60

9.36

6.46

4.46

3.08

2.13

1.47

1.02

0.71

 

7.80

5.92

4.08

2.82

1.95

1.35

0.94

0.66

0.46

 

8.00

3.74

2.59

1.79

1.24

0.86

0.60

0.43

0.30

 

8.20

2.37

1.64

1.14

0.79

0.56

0.39

0.28

0.20

 

8.40

1.51

1.05

0.73

0.51

0.36

0.26

0.19

0.14

 

8.60

0.96

0.67

0.47

0.33

0.24

0.17

0.13

0.10

 

8.80

0.62

0.43

0.31

0.22

0.16

0.12

0.09

0.07

 

9.00

0.40

0.28

0.20

0.15

0.11

0.09

0.07

0.06

 

Salinity = 30 g/kg

 

 

Temperature °C

 

pH

0

5

10

15

20

25

30

35

 

7.00

39.75

27.38

18.87

13.00

8.96

6.18

4.27

2.95

 

7.20

25.09

17.29

11.91

8.21

5.67

3.91

2.70

1.87

 

7.40

15.84

10.92

7.53

5.19

3.59

2.48

1.72

1.19

 

7.60

10.01

6.90

4.76

3.29

2.27

1.57

1.09

0.76

 

7.80

6.32

4.36

3.01

2.08

1.44

1.00

0.70

0.49

 

8.00

4.00

2.76

1.91

1.33

0.92

0.64

0.45

0.32

 

8.20

2.53

1.75

1.22

0.85

0.59

0.42

0.30

0.21

 

8.40

1.61

1.12

0.78

0.55

0.38

0.27

0.20

0.14

 

8.60

1.03

0.72

0.50

0.35

0.25

0.18

0.14

0.10

 

8.80

0.66

0.46

0.33

0.23

0.17

0.13

0.10

0.08

 

9.00

0.43

0.30

0.22

0.16

0.12

0.09

0.07

0.06

 

To calculate total ammonia nitrogen chronic criteria values in saltwater at different pH and temperature values than those listed in this subsection, use the following formulas:

I =

19.9273S

(1000 - 1.005109S)

Where I = molal ionic strength of water

S = Salinity ppt (g/kg)

The regression model used to relate I to pKa (negative log of the ionization constant) is

pKa = 9.245 + .138I 0.138(I)

pKa as defined by these equations is at 298 degrees Kelvin (25°C). T °Kelvin = °C + 273

To correct for other temperatures:

pKaST = pKaS298 + 0324(298 - T °Kelvin) 0.0324(298 - T °Kelvin)

The unionized ammonia fraction (UIA) is given by:

UIA =

1

1 + 10(pKaST-pH)

The chronic ammonia criterion in saltwater is given by:

Chronic =

.035 0.035

UIA

Multiply the chronic value by .822 0.822 to get the ammonia-N chronic criterion.

1The default design flow for calculating steady state wasteload allocations for the acute ammonia criterion for freshwater is the 1Q10 (see 9VAC25-260-140 B footnote 10) unless statistically valid methods are employed which demonstrate compliance with the duration and return frequency of the water quality criteria.

2The default design flow for calculating steady state wasteload allocations for the chronic ammonia criterion for freshwater is the 30Q10 (see 9VAC25-260-140 B footnote 10) unless statistically valid methods are employed which demonstrate compliance with the duration and return frequency of the water quality criteria.

9VAC25-260-185

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. The dissolved oxygen criteria in the below table apply to all Chesapeake Bay waters according to their specified designated use and supersede the dissolved oxygen criteria in 9VAC25-260-50.

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 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 Application

Shallow Water Submerged Aquatic Vegetation Use 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 light-through-water = 100e(-KdZ) where Kd is water column light attenuation coefficient and can be measured directly or converted from a measured secchi depth where Kd = 1.45/secchi depth. Z = depth at location of measurement of Kd.

C. Chlorophyll a.

Designated Use

Chlorophyll a Narrative Criterion

Temporal Application

Open Water 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 Rappahannock River

RPPOH

Western Branch Elizabeth River

WBEMH

Lower 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 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) , 2007 (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.

9VAC25-260-187

 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 waterbody in each of the two most recent monitoring years that chlorophyll a data are available. For a water body waterbody 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.

Man-made Lake or Reservoir Name

Location

Chlorophyll a (μg/L)

Total Phosphorus (μg/L)

Able Abel Lake

Stafford County

35

40

Airfield Pond

Sussex County

35

40

Amelia Lake

Amelia County

35

40

Aquia Reservoir (Smith Lake)

Stafford County

35

40

Bark Camp Lake (Corder Bottom Lake, Lee/Scott/Wise Lake)

Scott County

35

40

Beaver Creek Reservoir

Albemarle County

35

40

Beaverdam Creek Reservoir (Beaverdam Reservoir)

Bedford County

35

40

Beaverdam Reservoir

Loudoun County

35

40

Bedford Reservoir (Stony Creek Reservoir)

Bedford County

35

40

Big Cherry Lake

Wise County

35

40

Breckenridge Reservoir

Prince William County

35

40

Briery Creek Lake

Prince Edward County

35

40

Brunswick Lake (County Pond)

Brunswick County

35

40

Burke Lake

Fairfax County

60

40

Carvin Cove Reservoir

Botetourt County

35

40

Cherrystone Reservoir

Pittsylvania County

35

40

Chickahominy Lake

Charles City County

35

40

Chris Green Lake

Albemarle County

35

40

Claytor Lake

Pulaski County

25

20

Clifton Forge Reservoir (Smith Creek Reservoir)

Alleghany County

35

20

Coles Run Reservoir

Augusta County

10

10

Curtis Lake

Stafford County

60

40

Diascund Creek Reservoir

New Kent County

35

40

Douthat Lake

Bath County

25

20

Elkhorn Lake

Augusta County

10

10

Emporia Lake (Meherrin Reservoir)

Greensville County

35

40

Fairystone Lake

Henry County

35

40

Falling Creek Reservoir

Chesterfield County

35

40

Fluvanna Ruritan Lake

Fluvanna County

60

40

Fort Pickett Reservoir

Nottoway/Brunswick County

35

40

Gatewood Reservoir

Pulaski County

35

40

Georges Creek Reservoir

Pittsylvania County

35

40

Goose Creek Reservoir

Loudoun County

35

40

Graham Creek Reservoir

Amherst County

35

40

Great Creek Reservoir

Lawrenceville

35

40

Harrison Lake

Charles City County

35

40

Harwood Mills Reservoir

York County

60

40

Hidden Valley Lake

Washington County

35

40

Hogan Lake

Pulaski County

35

40

Holiday Lake

Appomattox County

35

40