Laws & Regulations

Fact Sheet

United States Environmental Protection Agency	Office of Water 4305	EPA-823-F-00-001 May 2001

Water Quality Standards; Proposed Withdrawal of Nutrient Standards for the State of Arizona

Summary

In 1976, EPA promulgated Federal criteria for nutrients in Arizona. The Federal criteria included numeric ambient water quality criteria for nutrients for eleven river segments and narrative water quality criteria for nutrients applicable to all surface waters in Arizona. Since then, Arizona adopted its own numeric and narrative water quality criteria for nutrients, which EPA approved. EPA also approved the implementation procedures for its narrative nutrient water quality criteria that Arizona established. Because the nutrient criteria and implementation procedures adopted by the State are scientifically defensible and consistent with the Clean Water Act, EPA is proposing to withdraw the Federal criteria for nutrients applicable in Arizona.

EPA is providing an opportunity for public comment on the withdrawal of the Federal nutrient criteria. The Agency wants to know if the public thinks it is appropriate for it to remove the Federal standards, which would leave in place the State's approved narrative criteria and implementation procedures as the basis for which designated uses would be protected.

Background

In 1976, EPA determined that Arizona's revisions to its water quality standards did not meet the requirements of the Clean Water Act (CWA). EPA promulgated Federal numeric nutrient criteria for total nitrates and total phosphates applicable to eleven river segments in Arizona. The Agency also promulgated narrative water quality criteria for nutrients applicable to all surface waters in Arizona. Effective June 22, 1976, these water quality criteria, codified at 40 CFR 131.31(a), became the applicable water quality criteria for nutrients in Arizona for all purposes and programs under the CWA.

Since EPA promulgated nutrient criteria for Arizona, the Arizona Department of Environmental Quality (ADEQ), in a series of actions, adopted numeric nutrient criteria for total nitrogen and total phosphorous applicable to specific water bodies in Arizona. Arizona also adopted narrative nutrient criteria and implementation procedures applicable to all surface waters of the State. EPA has determined that the numeric and narrative nutrient water quality criteria adopted by the State from 1976 to 1996, along with the implementation procedures for the narrative nutrient criteria, are fully protective of the designated uses of Arizona's waters and, as such, are consistent with the CWA and implementing Federal regulations. EPA has, therefore, determined that the 1976 Federal criteria for nutrients for Arizona waters are redundant and no longer necessary.

Today's Action

EPA's proposed rule, once finalized, will remove federally promulgated nutrient water quality criteria for the State of Arizona. Arizona's numeric and narrative nutrient criteria, along with the State's implementation procedures, will then become the only applicable water quality standards for Arizona.

Additional Information

For additional information about this rule, contact either of the following:

Gary Sheth
EPA Region 9
Water Division
75 Hawthorne Street
San Francisco, CA 94105
(415)744-2008
sheth.gary@epa.gov

Jennifer Wigal
EPA Headquarters
Office of Water (4305T)
1200 Pennsylvania Ave. NW
Washington, D.C. 20460
wigal.jennifer@epa.gov

You may view the Federal Register notice that describes this proposed rulemaking on the Internet at http://www.epa.gov/waterscience/standards/. The notice tells you how to get more information, review the complete administrative record, and provide public comment for this proposed rulemaking.