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Water: Nutrients

Arizona Criteria Development Progress

This page provides information about the progress Arizona has made towards the development of numeric criteria and shows what statewide and site-specific criteria are currently in effect.

Note: The information on the tabs below reflects the information available on EPA’s Water Quality Standards Repository. The criteria presented here will be updated as new water quality standards documents are posted to the Repository.


Numeric Criteria Development

The information presented below gives a summary of state progress towards the development of numeric criteria. The information comes from EPA’s “State Adoption of Numeric Nutrient Standards (1998-2008)” report, current water quality standards, program activity measures, and nutrient criteria development plans. Links to the Arizona’s Nutrient Criteria Plan and state water quality standards are also provided.


Existing Numeric Criteria

Waterbody Type N P Chl-a Clarity
Lakes and Reservoirs W W    
Rivers and Streams W W   W
Estuaries N ⁄ A N ⁄ A N ⁄ A N ⁄ A
Wetlands        

S = Statewide    W = For selected waterbody    N ⁄ A=Not Applicable

Note: See Statewide Criteria and Site-specific Criteria tabs for more information.

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You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

Plans:

WQS: Arizona Water Quality Standards 
Arizona Department of Environmental Quality: Water Quality Standards Exit EPA Disclaimer

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Milestone Information

Milestone information updated May 2012.


Milestone
Rivers and Streams Lakes and Reservoirs Estuaries and Coastal Waters
TN TP TN TP TN TP
Planning for criteria development  Complete  Complete  Complete  Complete  Not applicable  Not applicable
Collection of information and data 7/1/2015  7/1/2015  Complete  Complete  Not applicable  Not applicable
Analysis of information and data  7/1/2017  7/1/2017  Complete  Complete  Not applicable  Not applicable
Proposal of criteria  No date provided  No date provided  No date provided  No date provided  Not applicable  Not applicable
Adoption of criteria (EPA-Approved)  No date provided  No date provided  No date provided  No date provided  Not applicable  Not applicable

TN: Total Nitrogen; TP: Total Phosphorus

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Statewide Criteria

The information on this tab shows EPA-approved nutrient criteria for Arizona’s waterbodies. The language presented below comes directly from state water quality standards and applies to all waterbodies within the state (unless a waterbody type or designated use is noted). Criteria applicable to specific waterbodies within the state can be found on the “Site-specific Criteria” tab. For more information, refer to the Arizona water quality standards.

The following information reflects Arizona’s water quality standards posted to the Water Quality Standards Repository as of November 2010 (EPA-approved March 2002).

R18-11-108. Narrative Water Quality Standards

A. A surface water shall not contain pollutants in amounts or combinations that:

2. Cause objectionable odor in the area in which the surface water is located;

3. Cause off-taste or odor in drinking water;

4. Cause off-flavor in aquatic organisms;

6. Cause the growth of algae or aquatic plants that inhibit or prohibit the habitation, growth, or propagation of other aquatic life or that impair recreational uses;

8. Change the color of the surface water from natural background levels of color.

Site-specific Criteria

The information on this tab shows EPA-approved site-specific nutrient criteria for Arizona’s waterbodies. Criteria on this page apply only to the waterbodies listed below. Criteria applicable to all waterbodies within the state are found on the “Statewide Criteria” tab. For more information, refer to the Arizona water quality standards.

The following information reflects Arizona’s water quality standards posted to the Water Quality Standards Repository as of November 2010 (EPA-approved March 2002).

R18-11-109. Numeric Water Quality Criteria

E. Nutrient criteria. The following water quality standards for total phosphorus and total nitrogen are expressed in milligrams per liter (mg/L). A minimum of 10 samples, each taken at least 10 days apart in a consecutive 12-month period, are required to determine a 90th percentile. Not more than 10 percent of the samples may exceed the 90th percentile value listed below:

  Surface Water Annual Mean 90th Percentile Single Sample Maximum
1. Verde River and its tributaries from the Verde headwaters to Bartlett Lake:
  Total phosphorus 0.10 0.30 1.00
  Total nitrogen 1.00 1.50 3.00
2. Black River, Tonto Creek and their tributaries that are not located on tribal lands:
  Total phosphorus 0.10 0.20 0.80
  Total nitrogen 0.50 1.00 2.00
3. Salt River and its tributaries above Roosevelt Reservoir, excluding Pinal Creek, that are not located on tribal lands:
  Total phosphorus 0.12 0.30 1.00
  Total nitrogen 0.60 1.20 2.00
4. Theodore Roosevelt, Apache, Canyon, and Saguaro Lakes:
  Total phosphorus 0.03   0.60
  Total nitrogen 0.30   1.00
5. Salt River below Stewart Mountain Dam to its confluence with the Verde River:
  Total phosphorus 0.05   0.20
  Total nitrogen 0.60   3.00
6. Little Colorado River and its tributaries above River Reservoir in Greer; South Fork of Little Colorado River above South Fork Campground; and Water Canyon Creek above Apache-Sitgreaves National Forest boundary:
  Total phosphorus 0.08 0.10 0.75
  Total nitrogen 0.60 0.75 1.10
7. Little Colorado River at the crossing of Apache County Road No. 124:
  Total phosphorus     0.75
  Total nitrogen     1.80
8. Little Colorado River above Lyman Lake to above the Amity Ditch diversion near crossing of Arizona Highway 273 (applies only when in-stream turbidity is less than 50 NTU):
  Total phosphorus 0.20 0.30 0.75
  Total nitrogen 0.70 1.20 1.50
9. Colorado River at the Northern International Boundary near Morelos Dam:
  Total phosphorus   0.33  
  Total nitrogen   2.50  
10. San Pedro River, from Curtis to Benson:
  Total phosphorus      
  Total nitrogen     10.00
11. No discharge of wastewater to Show Low Creek or its tributaries upstream of and including Fools Hollow Lake shall exceed 0.16 mg/L total phosphates as P.
12. No discharge of wastewater to the San Francisco River or its tributaries upstream of Luna Lake Dam shall exceed 1.0 mg/L total phosphates as P.

R18-11-112. Unique Waters

H. The following water quality standards apply to the listed unique waters. Water quality standards prescribed in this subsection supplement the water quality standards prescribed by this Article.

2. Oak Creek, including the West Fork of Oak Creek
Parameter Standard
Turbidity change due to discharge 3 NTUs
3. Peoples Canyon Creek, tributary to the Santa Maria
Parameter Standard
Turbidity change due to discharge 5 NTUs
6. Cienega Creek, from its confluence with Gardner Canyon and Spring Water Canyon 261 at R18E T17S to Del Lago Dam, in Pima County
Parameter Standard
Turbidity 10 NTUs
7. Bonita Creek, tributary to the Upper Gila River
Parameter Standard
Turbidity 15 NTUs

Abbreviations:
 “NTUs” means nephelometric turbidity units


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