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The Tribe adopts the following water quality standards for the following designated uses for specific Tribal water bodies. The Tribe adopts the following water quality standards for the designated uses of waters within and adjacent to the YIR:

(a) Waters listed with the designated uses of preservation of biological habitat with special significance (BIO), cold freshwater habitat (COL), commercial and sport fishing (COM), cultural and ceremonial activities (CUL), migration of aquatic organisms (MGR), municipal and domestic supply (MUN), navigation (NAV), contact recreation (REC-1), rare, threatened, or endangered species habitat (RARE), spawning, reproduction, and development habitat (SPN) shall meet the following criteria over the entire length of the stream, including connecting tributaries and the Pacific Ocean where applicable within Tribal jurisdiction.

(1) Bacteriological Criteria. Bacterial criteria for fresh and coastal waters use a geometric mean and a single sample maximum, which shall not exceed the following:

Bacteria

Geometric Mean

Single Sample Max

enterococci

33 CFU/100 ml

61 CFU/100 ml

Escherichia coli

126 CFU/100 ml

235 CFU/100 ml

CFUs – Coliform-Forming Units

(2) Conductivity. Specific conductivity levels shall have a 90 percent upper limit of 300 μmhos/cm at 25° Celsius (77° Fahrenheit) and a 50 percent upper limit of 200 μmhos/cm at 25° Celsius (77° Fahrenheit). This criterion does not apply to estuarine and coastal waters.

(3) Water temperature standards.

Life Stage

Time Period (Estimated)

MWAT (C/F)

MWMT (C/F)

Inst. Max
(C/F)

Adult Migration

Year-round

15/59

17/62.6

21/69.8

Adult Holding

May – Dec

14/57.2

16/60.8

22/71.6

Spawning

Sept – April

11/51.8

13/55.4

22/71.6

Incubation/Emergence All Salmonids except Coho

Jan – May

11/51.8

13/55.4

22/71.6

Incubation/Emergence Coho Salmon

Nov – June

10/50

12/53.6

22/71.6

Juvenile Rearing

Year-round

15/59

17/62.6

22/71.6

Smoltification

Jan – June

12/53.6

14/57.2

22/71.6

(4) pH. pH levels shall not be below 6.5 and not exceed 8.5 due to human-caused activities.

(5) Dissolved Oxygen.

(A) Year-round objective in the water column: A seven-day moving average of the daily minimum concentrations greater than or equal to eight mg/l;

(B) Intergravel objective during the incubation and emergence life stage: A seven-day moving average of the daily minimum concentrations greater than or equal to eight mg/l;

(C) Water column objective during the incubation and emergence life stage: A seven-day moving average of the daily minimum concentrations greater than or equal to 11 mg/l.

(6) Hardness levels. Hardness levels shall have a 50 percent upper limit of 80 mg/l of calcium carbonate. This criterion does not apply to estuarine and coastal waters.

(7) Boron levels. Boron levels shall have a 90 percent upper limit of 0.5 mg/l and a 50 percent upper limit of 0.2 mg/l. This criterion does not apply to estuarine areas.

(8) Ammonia. Because ammonia toxicity to fish is influenced by pH and temperature, the above-listed waters shall meet the following conditions for ammonia1 based on the pH and temperature in the waterbody:

1Ammonia levels adopted from EPA’s 1999 update of ambient water quality criteria for ammonia and Hoopa Valley Tribe’s WQCP, 2001.

The one-hour average concentration of total ammonia nitrogen (in mg N/L) does not exceed, more than once every three years on the average, the CMC (acute criterion) calculated using the following equation. Where salmonid fish are present:

CMC = (0.275 ) / (1 + 107.204 – pH ) + (39.0) / (1 + 10pH – 7.204)

Based on this equation, ammonia toxicity values for a given pH value are provided in the following table.

When surface waters are at the specified pH levels in the table below total ammonia shall not be above the levels stated in the table below.

Total Ammonia (mg N/L) Toxicity Table

(for salmonids in freshwater at various expected pH levels)

pH

mg N/L

6.0

36.72

6.5

32.6

7.0

24.1

7.5

13.3

8.0

5.62

8.5

2.14

9.0

0.885

The 30-day average concentration of total ammonia nitrogen (in mg N/L) should not exceed, more than once every three years on the average, the CCC (chronic criterion) calculated using the following equation. When fish early life stages are present:

CCC = {( 0.0577) / (1 + 107.688 – pH) + (2.487 ) / (1 + 10pH – 7.688)} x MIN(2.85, 1.45 x 100.028 x (25 – T))

In addition, the highest four-day average within the 30-day period should not exceed 2.5 times the CCC.

(b) For all waters listed with the designated beneficial uses for agricultural supply (AGR), estuarine habitat (EST), and/or freshwater replenishment (FRSH), ground water recharge (GW), marine habitat (MAR), power supply (PWR), nonrecreation contact (REC-2), warm water habitat (WARM) and wildlife habitat (WLD), no criteria have been set due to the fact that these waters already have been designated as supporting beneficial uses that require more stringent water quality standards. Therefore, the more stringent water quality standards supersede any standards that may be protective of these beneficial uses. [Res. 04-46 § 3.5, adopted, 8/25/2004.]