Nutrient Criteria Development; Notice of Nutrient Criteria Technical Guidance Manual: Rivers and Streams

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice of nutrient criteria technical guidance manual: rivers and streams.

SUMMARY:

The Environmental Protection Agency announces the availability of a nutrient criteria technical guidance manual for Rivers and Streams. This document provides State and Tribal water quality managers and others with guidance on how to develop numeric nutrient criteria for Rivers and Streams. This document does not contain site-specific numeric nutrient criteria for any river or stream systems. 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 for 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, the Agency 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 by September 25, 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: Rivers and Streams. 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:

Debra Hart, USEPA, Health and Ecological Criteria Division (4304), Office of Science and Technology, Ariel Rios Building, 1200 Pennsylvania Ave., NW, Washington, DC 20460; or call (202) 260-0905; fax (202) 260-1036; or e-mail hart.debra@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. The Strategy 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 Rivers and Streams, 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 Rivers and Streams

EPA initiated the National Strategy to Develop Regional Nutrient Criteria to address enrichment problems. The Nutrient Criteria Technical Guidance Manual: Rivers and Streams is the second 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 estuarine/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, other Federal agencies, State, and Tribal representatives who are working together to use EPA's forthcoming section 304(a) nutrient criteria guidance as a starting point for developing 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.) Today's manual for Rivers and Streams 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.

A directly prescriptive approach to nutrient criteria development is not appropriate due to regional differences that exist and the lack of a clear technical understanding of the relationship between nutrients, algal growth, and other factors (e.g., flow, light, substrata). Therefore, the approach chosen for criteria development must be tailored to meet the specific needs of each State or Tribe. The criteria development process described in this guidance can be divided into the following iterative steps.

1. Identify water quality needs and goals with regard to managing nutrient enrichment problems.

2. Classify rivers and streams first by type, and then by trophic status.

3. Select variables for monitoring nutrients, algae, macrophytes, and their impacts.

4. Design sampling program for monitoring nutrients and algal biomass in rivers and streams.

5. Collect data and build database.

6. Analyze data.

7. Develop criteria based on reference condition and data analyses.

8. Implement nutrient control strategies.

9. Monitor effectiveness of nutrient control strategies and reassess the validity of nutrient criteria.

The components of each step are explained in detail in succeeding chapters of the document. Appended to the guidance document are case studies from various ecoregions around the country and technical discussions of analytical methods, statistical analyses, and computer modeling.

The Nutrient Criteria Technical Guidance Document: Rivers and Streams that is being announced in this Notice was developed after consideration of public comment and peer review. The draft technical guidance manual for Rivers and Streams was placed on the EPA Nutrient website (http://www.EPA.gov/OST/standards/nutrient.html) on October 8, 1999, and EPA accepted correspondences and comments until June 23, 2000. In addition, a peer review of the proposed criteria document was conducted by a panel of five external reviewers.