§131.31 Arizona.

Link to an amendment published at 68 FR 62744, November 6, 2003.

(a) Article 6, part 2 is amended as follows:

(1) Reg. 6-2-6.11 shall read:

Reg. 6-2-6.11    Nutrient Standards. A. The mean annual total phosphate and mean annual total nitrate concentrations of the following waters shall not exceed the values given below nor shall the total phosphate or total nitrate concentrations of more than 10 percent of the samples in any year exceed the 90 percent values given below. Unless otherwise specified, indicated values also apply to tributaries to the named waters.

 
------------------------------------------------------------------------
                                                    Mean 90 pct annual
                                                           value
                                                 -----------------------
                                                     Total       Total
                                                  phosphates   nitrates
                                                      as          as
                                                  PO[INF]4[/  NO[INF]3[/
                                                   INF] mg/l   INF] mg/l
------------------------------------------------------------------------
1. Colorado River from Utah border to Willow       0.04-0.06         4-7
 Beach (main stem)..............................
2. Colorado River from Willow Beach to Parker      0.06-0.10           5
 Dam (main stem)................................
3. Colorado River from Parker Dam to Imperial      0.08-0.12         5-7
 Dam (main stem)................................
4. Colorado River from Imperial Dam to Morelos     0.10-0.10         5-7
 Dam (main stem)................................
5. Gila River from New Mexico border to San        0.50-0.80  ..........
 Carlos Reservoir (excluding San Carlos
 Reservoir).....................................
6. Gila River from San Carlos Reservoir to         0.30-0.50  ..........
 Ashurst Hayden Dam (including San Carlos
 Reservoir).....................................
7. San Pedro River..............................   0.30-0.50  ..........
8. Verde River (except Granite Creek)...........   0.20-0.30  ..........
9. Salt River above Roosevelt Lake..............   0.20-0.30  ..........
10. Santa Cruz River from international boundary   0.50-0.80  ..........
 near Nogales to Sahuarita......................
11. Little Colorado River above Lyman Reservoir.   0.30-0.50  ..........
------------------------------------------------------------------------

B. The above standards are intended to protect the beneficial uses of the named waters. Because regulation of nitrates and phosphates alone may not be adequate to protect waters from eutrophication, no substance shall be added to any surface water which produces aquatic growth to the extent that such growths create a public nuisance or interference with beneficial uses of the water defined and designated in Reg. 6-2-6.5.

(2) Reg. 6-2-6.10      Subparts A and B are amended to include Reg. 6-2-6.11 in series with Regs. 6-2-6.6, 6-2-6.7 and 6-2-6.8.

(b) The following waters have, in addition to the uses designated by the State, the designated use of fish consumption as defined in R18-11-101 (which is available from the Arizona Department of Environmental Quality, Water Quality Division, 3033 North Central Ave., Phoenix, AZ 85012):

COLORADO MAIN STEM RIVER BASIN:
    Hualapai Wash

MIDDLE GILA RIVER BASIN:
    Agua Fria River (Camelback Road to Avondale WWTP)

    Galena Gulch

    Gila River (Felix Road to the Salt River)

    Queen Creek (Headwaters to the Superior WWTP)

    Queen Creek (Below Potts Canyon)

SAN PEDRO RIVER BASIN:
    Copper Creek

SANTA CRUZ RIVER BASIN:
    Agua Caliente Wash

    Nogales Wash

    Sonoita Creek (Above the town of Patagonia)

    Tanque Verde Creek

    Tinaja Wash

    Davidson Canyon

UPPER GILA RIVER BASIN
    Chase Creek

(c) To implement the requirements of R18-11-108.A.5 with respect to effects of mercury on wildlife, EPA (or the State with the approval of EPA) shall implement a monitoring program to assess attainment of the water quality standard. (Sec. 303, Federal Water Pollution Control Act, as amended, 33 U.S.C. 1313, 86 Stat. 816 et seq., Pub. L. 92-500; Clean Water Act, Pub. L. 92-500, as amended; 33 U.S.C. 1251 et seq.)

[41 FR 25000, June 22, 1976; 41 FR 48737, Nov. 5, 1976. Redesignated and amended at 42 FR 56740, Oct. 28, 1977. Further redesignated and amended at 48 FR 51408, Nov. 8, 1983; 61 FR 20693, May 7, 1996]