Document Headings

                    Document headings vary by document type but may contain                    the following:                  
                -                       the agency or agencies that issued and signed a document                    
                -                       the number of the CFR title and the number of each part                      the document amends, proposes to amend, or is directly                      related to                    
                -                       the agency docket number / agency internal file number                    
                -                       the RIN which identifies each regulatory action listed in                      the Unified Agenda of Federal Regulatory and Deregulatory                      Actions                    

                    See the                                          Document Drafting Handbook                                        for more details.                  

###### Environmental Protection Agency.

          - [FRC-670S-1]

# AGENCY: 

Environmental Protection Agency (EPA). 

# ACTION: 

Notice of nutrient criteria technical guidance manual: Lakes and reservoirs, first edition. 

# SUMMARY: 

The Environmental Protection Agency (EPA) announces the availability of a nutrient criteria technical guidance manual for lakes and reservoirs. This document provides State and Tribal water quality managers and others with guidance on how to develop numeric nutrient criteria for lakes and reservoirs. This document does not contain site-specific numeric nutrient criteria for any lake or reservoir. This guidance was principally developed to assist States and Tribes in their efforts to establish nutrient criteria. States and Tribes are clearly 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, and might not apply to a particular situation based upon the circumstances. 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 have decided to issue technical guidance in a manner similar to that which we are using 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). Therefore, we invite the public to provide scientific views on this guidance. We will review and consider information submitted by the public on significant scientific issues that might not have otherwise been identified by the Agency during development of this guidance. This guidance has been through external peer review, and a summary of these comments is available on the Nutrient website (http://www. EPA.gov/OST/standards/nutrient.html) After review of the submitted significant scientific information, we will publish a revised document, or publish a notice indicating its decision not to revise the document.                     

This document has been prepared for publication by the Office of Science and Technology, Office of Water, U.S. Environmental Protection Agency. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. 

# DATES: 

All significant scientific information must be submitted to the Agency by July 24, 2000. Any scientific information submitted should be adequately documented and contain enough supporting information to indicate that acceptable and scientifically defensible procedures were used and that the results are likely reliable. 

# ADDRESSES: 

                        This notice contains a summary of the Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs, First Edition. Copies of the complete document may be obtained from EPA's Water Resource Center by phone at 202-260-7786, or by e-mail to: center.water-resource@epa.gov, or by conventional mail to EPA Water Resource Center, RC-4100, Ariel Rios Building, 1200 Pennsylvania Ave., NW, Washington, DC 20460. The document is also available electronically at                         *http://www.epa.gov/​OST/​standards/​nutrient.html.*

An original and two copies of written significant scientific information should sent to Robert Cantilli (MC-4304), U.S. EPA, Ariel Rios Building, 1200 Pennsylvania Ave., NW , Washington, DC 20460. Written significant scientific information may be submitted electronically in ASCII or Word Perfect 5.1, 5.2, 6.1, or 8.0 formats to OW-General@epa.gov. 

# FOR FURTHER INFORMATION CONTACT: 

Dr. George Gibson, USEPA, Health and Ecological Criteria Division (4304), Office of Science and Technology, Ariel Rios Building, 1200 Pennsylvania Ave., NW, Washington, DC 20460; or call (410) 305-2618; fax (410) 305-3093; or e-mail gibson.george@epa.gov. 

# SUPPLEMENTARY INFORMATION:

## Introduction 

                    On March 24, 1998, the President's Clean Water Action Plan was presented in the                     **Federal Register**                    . The Clean Water Action Plan specifically stated that EPA will establish recommended water quality criteria for nutrients that reflect the different types of water bodies and different ecoregions of the country and that will assist States and Tribes in adopting numeric water quality standards for nutrients. Consistent with the objectives of the Clean Water Action Plan, the U.S. Environmental Protection Agency presented a National Strategy for the Development of Regional Nutrient Criteria on June 25, 1998, that described the approach the Agency would follow in developing nutrient information and working with States and Tribes to adopt nutrient criteria as part of State/Tribal water quality standards. The major focus of the strategy is the development of waterbody-type technical guidance and recommended ecoregion-specific nutrient criteria by the year 2000. Once EPA develops waterbody-type guidance and recommended nutrient criteria, EPA intends to assist States and Tribes in adopting numeric nutrient criteria into water quality standards by the end of 2003.                 

## Overview of the Problem 

                    Cultural eutrophication (                    *i.e.,*                    that associated with humans) of United States surface waters is a long-standing problem; approximately half of the reported impairments in National waters are attributable to excess nutrients. Nitrogen and phosphorus are the primary cause of eutrophication, and algal blooms are often a response to enrichment. Within lakes and reservoirs, chronic symptoms of overenrichment include low dissolved oxygen, fish kills, increased sediment accumulation, and species and abundance shifts of flora and fauna. The problem is National in scope, but varies in nature from one region of the country to another due to geographical variations in geology and soil types. For these reasons, EPA has decided to develop its recommend nutrient criteria on an ecoregional basis for use by States and Tribes.                 

## Summary of Nutrient Criteria Technical Guidance Manual for Lakes and Reservoirs 

                    EPA initiated the National Strategy to Develop Regional Nutrient Criteria to address enrichment problems. The                           ( print page 33323)                        Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs, First Edition is the first of a series of waterbody-type specific manuals produced to assist EPA Regions, States, and Tribes in establishing ecoregionally appropriate nutrient criteria. EPA is also developing manuals for rivers and streams, estuarine and coastal waters, and wetlands. EPA expects States and Tribes to use these manuals as the basis for developing State water quality standards for nutrients, to help identify water quality impairments, and to evaluate the relative success in reducing cultural eutrophication. In addition to developing these waterbody-type specific manuals, EPA is developing nutrient criteria guidance under section 304(a) for each of the 14 ecoregions it has 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 the nutrient water quality criteria eventually adopted by States and Tribes are tailored to more localized conditions. In order to assist States and Tribes in this undertaking, as well as to verify section 304 (a) nutrient criteria guidance, and to provide national consistency wherever possible, EPA has established Regional Technical Assistance Groups (RTAGs). RTAGs are a collection of EPA, State, Tribal representatives who are working together to take EPA's forthcoming section 304(a) nutrient criteria guidance as a starting point to develop more refined ecoregional nutrient criteria. (EPA is also using data and expertise provided by the RTAGs in the development of its section 304(a) nutrient criteria guidance for the 14 ecoregions it has identified.) EPA expects the RTAGs to use the processes set forth in the waterbody-type specific manuals to develop recommended nutrient criteria on an ecoregional basis or a more refined basis (such as subecoregion, State or Tribe-level, more defined class of lakes/reservoirs). Today's manual for lakes and reservoirs also explains how States or Tribes can adopt nutrient water quality standards based on the ecoregional criteria values recommended by the EPA and/or RTAGs.                 

The key parameters addressed in Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs, First Edition are total phosphorus, total nitrogen, chlorophyll a, and Secchi depth. As set forth in the manual, the elements that EPA expects States and Tribes to consider in developing a nutrient criterion are: 

(1) Historical data and other information to establish perspective; 

(2) Current reference site information; 

(3) Models used to simulate or validate the empirical relationships established between causal (nutrients) and response (biological indicators) variables; and 

(4) Evaluation of downstream consequences before finalizing criteria values. EPA also expects the States or Tribes (or the RTAG when developing criteria guidance) to use their best professional judgement when examining the information and establishing criteria. 

EPA expects the criteria development and implementation process (undertaken by EPA, the RTAGs and others) to proceed as follows: 
    - Data acquisition and review, as well as additional data gathering and processing methods.
    - Classification of the lakes and reservoirs by physical characteristics.
    - Reference site selection and data reduction to identify reference conditions.
    - Development of defensible nutrient criteria, verified by an RTAG and evaluated for potential downstream effects.
    - Adoption of nutrient criteria by States and Tribes into their water quality. Standards, ideally taking into account the reference condition data and designated uses.
    - Implementation of EPA-approved nutrient criteria by EPA, States, and Tribes to identify areas of water quality impairment due to nutrients and to respond appropriately.

These subjects are described in detail in the Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs, First Edition. 

The manual concludes with chapters describing data models and management options that actively protect or restore lake and reservoir resources. Case histories illustrating nutrient criteria development experiences are appended with the names of individual specialists to contact for more information. 

The Nutrient Criteria Technical Guidance Document: Lakes and Reservoirs, First Edition that is being announced in this Notice was developed after consideration of public comment and peer review. A draft Technical Guidance Manual: Lakes and Reservoirs was placed on the EPA Nutrient website (http://www.EPA.gov/​OST/​standards/​nutrient.html) on September 8, 1999, and EPA accepted correspondences and comments until November 16, 1999. In addition, a peer review of the proposed criteria document was conducted by a panel of five external reviewers. 

Dated: May 4, 2000.

Geoffrey H. Grubbs,

Director, Office of Science and Technology. 

[FR Doc. 00-12955 Filed 5-22-00; 8:45 am] 

BILLING CODE 6560-50-P