[Code of Federal Regulations]
[Title 40, Volume 18]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR131.31]
[Page 378-379]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 131--WATER QUALITY STANDARDS--Table of Contents
Subpart D--Federally Promulgated Water Quality Standards
Sec. 131.31 Arizona.
(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 PO4 mg/ as NO3 mg/
l 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)
[[Page 379]]
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]