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Nutrient Criteria Development; Notice of Nutrient Criteria Technical Guidance Manual: Estuarine and Coastal Marine Waters

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Environmental Protection Agency (EPA).


Notice of final Nutrient Criteria Technical Guidance Manual: Estuarine and Coastal Marine Waters.


The Environmental Protection Agency announces the availability of a final nutrient criteria technical guidance manual for estuaries and coastal marine waters. This document gives State and Tribal water quality managers and others guidance on how to develop numeric nutrient criteria for estuaries and coastal marine waters. This document does not contain site-specific numeric nutrient criteria for any estuary or coastal marine water. This guidance was developed to help States and Tribes establish nutrient criteria. States and Tribes are in the best position to consider site-specific conditions in developing nutrient criteria. While this guidance contains EPA's scientific recommendations regarding defensible approaches for developing regional nutrient criteria, this guidance is not regulation. Thus it does not impose legally binding requirements on EPA, States, Territories, Tribes, or the public. States, Territories, and authorized Tribes retain the discretion to adopt, where appropriate, other scientifically defensible approaches to developing regional or local nutrient criteria that differ from these recommendations.

We are issuing this technical guidance in a manner similar to that used to issue new and revised criteria (see Federal Register, December 10, 1998, 63 FR 68354 and in the EPA document titled, National Recommended Water Quality—Correction EPA 822-Z-99-001, April 1999). EPA notified the public about the availability of the draft guidance manual and peer review on October 10, 2001 (66 FR 51665). At that time, the Agency solicited views from the public on issues of science pertaining to the information contained in the draft technical guidance manual. EPA considered the scientific views from the peer reviewers and the public and has revised the document accordingly. The completed document is now available.


You can get copies of the completed document entitled “Nutrient Criteria Technical Guidance Manual: Estuarine and Coastal Waters” from EPA's National Service Center for Environmental Publications (NSCEP) by phone at (513) 489-8190 or toll free (800) 490-9198 or by e-mail to:, or by conventional mail to NSCEP, 11029 Kenwood Road, Cincinnati, OH 45242. The document is also available electronically at​OST/​standards/​nutrient.html.

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Dr. David Flemer, USEPA, Health and Ecological Criteria Division (4304T), Office of Science and Technology, Ariel Rios Building, 1200 Pennsylvania Ave., NW., Washington, DC 20460; or call (202) 566-1101; fax (202) 566-1139; or e-mail

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What Are Nutrient Criteria Technical Guidance Manuals?

Nutrient Criteria Technical Guidance Manuals are documents that give States and Tribes information to help develop water quality criteria and standards for nutrients, identify water quality impairments, and evaluate their success in reducing cultural eutrophication. They are intended to provide a series of steps leading to the development of nutrient criteria for a specific waterbody type.

EPA began to implement a National Strategy to Develop Regional Nutrient Criteria in 1998 to address enrichment problems. The Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs, First Edition (EPA-822-B00-001) was the first of a series of waterbody-type specific manuals produced to help States, and Tribes establish ecoregionally appropriate nutrient criteria. EPA also developed a manual for rivers and streams (Nutrient Criteria Technical Guidance Manual: Rivers and Streams—EPA-822-B-00-002, and is developing a manual for wetlands. In addition to these waterbody-type specific manuals, EPA is developing nutrient criteria guidance under section 304(a) for each of the 14 ecoregions it identified in the continental United States. EPA expects States and Tribes to use the manuals, other information and local expertise to refine EPA's 304(a) nutrient criteria guidance so that their nutrient water quality criteria are tailored to local conditions. To help States and Tribes, to verify section 304(a) nutrient criteria guidance, and to provide national consistency wherever possible, EPA established Regional Technical Assistance Groups (RTAGs). RTAGs are a collection of EPA, State, Tribal representatives who work together to develop more refined ecoregional nutrient criteria, using the forthcoming section 304(a) guidance as a starting point. (EPA is also using data and expertise provided by the RTAGs to develop its section 304(a) nutrient criteria guidance for the 14 ecoregions it identified.) EPA expects the RTAGs to use the processes described in the waterbody-type specific manuals to develop recommended nutrient criteria on an ecoregional or more refined basis (such as subecoregion, coastal province, State or Tribe-level more defined class of estuary/coastal marine water). Today's manual for estuarine and coastal marine waters also explains how States or Tribes can adopt nutrient water quality standards based on the criteria values recommended by the EPA and/or RTAGs.

How Did EPA Involve the Public in Revising the Estuarine Coastal Guidance Manual?

In following the Agency's process for developing criteria and other guidance, EPA notified the public of the availability of the peer reviewed draft of the Estuarine Coastal Nutrient Criteria technical Guidance Manual on October 10, 2001 (66 FR 51665). EPA asked for views from the public on issues of science pertaining to information contained in the guidance manual. EPA considered the scientific views from the peer review and the public to revise the document.

Is the Completed Document Different Than the Draft Document?

In addressing the peer reviewers' comments and submissions of significant scientific information from the public, EPA made revisions to the draft document. Many of the submissions from the public were also presented by the peer reviewers, and these were addressed in the final document. To review the complete set of peer review comments and scientific views provided by the public, together with EPA's responses, go to​waterscience/​standards/​nutrient.html.

A number of peer review comments and scientific views presented by the public questioned the use of a frequency distribution approach to develop a reference condition. The manual was rewritten to offer several methods for developing reference conditions, including several that do not use a frequency distribution. In addition, the manual is now more clear on distinguishing reference condition from criteria. Reference condition is one element of criteria derivation that RTAGs should consider with historical background information, possible model extrapolations of data, and possible downstream impacts.

Another submission questioned the utility of EPA's approach in developing estuarine/coastal criteria, since many reference conditions no longer exist. EPA added language to the guidance acknowledging that pre-Columbian, pristine conditions are rare and that the goal of the nutrient criteria setting process is to strive for a reference condition value and criteria that represent the most natural condition possible (as measured from sites having the least amount of human influence). Since extensive degradation of estuaries systems has been reported, the guidance manual describes four options for establishing reference conditions in estuaries (one option is presented for coastal waters). The manual also places greater emphasis on historical information because the reference condition of estuaries may be degraded, and estuaries, in particular, can seldom be classified by using a frequency distribution.

Several scientific views stated that the nutrient criteria that might be derived using the guidance manual do not support specific designated uses. It is true that the potential criteria derived may not be specific to a designated use. Rather, because they are reference condition-based, they should support the broad array of aquatic life uses in accordance with the Clean Water Act. As stated in the final guidance manual, the criteria derived using the manual are intended as benchmarks for comparison when a State or Tribe prepares their own criteria based on specific uses.

An additional public viewpoint indicated that nutrient criteria as developed by EPA are unnecessary because States already have criteria identifying conditions associated with eutrophication, such as dissolved oxygen, pH, and turbidity. States have used response variables such as dissolved oxygen, pH, and turbidity to reveal nutrient problems in their waters, but the root cause of eutrophication, as demonstrated by excess primary productivity, is typically nitrogen and phosphorus. For more effective prevention, it is important to measure the level and extent of the causal agents. The criteria are based directly on these primary causal elements of total nitrogen and phosphorus plus two early response variables. These are algal biomass (e.g., chlorophyll-a for microalgae, dry mass for macroalgae) and water clarity, which most often indicate the early vegetative response to nutrient enrichment. Because many estuaries experience or may experience hypoxia, dissolved oxygen was added as an additional response variable.

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Dated: December 20, 2002.

Geoffrey H. Grubbs,

Director, Office of Science and Technology.

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[FR Doc. 03-175 Filed 1-3-03; 8:45 am]