Form for Compliance with E.O. 12866 Docket Requirements

Title of Regulation: Water Quality Standards for the State of Florida’s Streams and 

Downstream Protection Values for Lakes: Remanded Provisions

 

Contact person: Mario Sengco 

Phone number: 202-566-2676 

Was this regulation reviewed by OMB under Executive Order 12866 - Regulatory Planning 

and Review?

X Yes No 

If you checked “no”, you are done with this form. Simply place it in the docket for your 

regulation. If you checked “yes”, please fill out the remainder of the form before placing it in 

the docket. Also docket any relevant documents referenced in the form.

For regulations that are checked “Yes” above:

This regulation was reviewed by OMB under Executive Order 12866 - Regulatory Planning and 

Review. 

Attached is the draft regulation and any other documents sent to OMB for review, such as 

analyses and assessments. E.O. 12866 requires agencies to make these publicly available.

E.O. 12866 also requires agencies to identify the substantive changes between the draft 

regulation sent to OMB for review and the regulation subsequently announced [Please check the 

appropriate box below:] 

 X EPA made substantive changes to this regulation

(includes changes initiated by EPA or OMB). 

Attached is a document which: (1) identifies all the substantive changes made, and (2) 

notes those changes OMB suggested or recommended.

 No substantive changes were made to this regulation

Therefore, no further attachments are required.

If you have questions about this regulation, please call the EPA contact person listed above.


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6560-50-P

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 131

[EPA-HQ-OW-2009-0596; FRL#9678-6]

RIN 2040-AF39

Water Quality Standards for the State of Florida’s Streams and Downstream 

Protective Values for Lakes: Remanded Provisions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

SUMMARY: The Environmental Protection Agency (EPA or Agency) is proposing a 

rule that addresses an order by the U.S. District Court for the Northern District of Florida 

from February 18, 2012, which remanded to EPA two portions of its numeric water 

quality standards for nutrients in Florida that were promulgated and published on 

December 6, 2010. For this proposal, EPA is re-proposing the same numeric nutrient 

criteria for total nitrogen (TN) and total phosphorus (TP) for Florida streams not covered 

by EPA-approved State rulemaking, as included in EPA’s final rule, with further 

explanation of how the proposed numeric streams criteria will ensure the protection of 

the Florida’s Class I and III designated uses. EPA is also proposing default approaches 

available for use when modeling cannot be performed to derive downstream protection 

values (DPVs) that will ensure the attainment and maintenance of the numeric nutrient 

criteria that protect Florida’s lakes. The default approaches would be applicable to 

streams that flow into unimpaired lakes, but could also be used for streams that flow into 

Comment [MS1]: EPA will use the term, 

“streams criteria” consistently in this document.
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impaired lakes.

DATES: EPA will accept public comments on this proposed rule until [Insert date 45

days from date of publication in the Federal Register]. Because of EPA’s obligation to 

sign a notice of final rulemaking on or before August 31, 2013 under Consent Decree, the 

Agency regrets that it will be unable to grant any requests to extend this deadline.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OW2009-0596, by one of the following methods:

1. www.regulations.gov: Follow the on-line instructions for submitting comments.

2. Email: ow-docket@epa.gov

3. Mail to: Water Docket, U.S. Environmental Protection Agency, Mail code: 

2822T, 1200 Pennsylvania Avenue, NW, Washington, DC 20460, Attention: 

Docket ID No. EPA-HQ-OW-2009-0596.

4. Hand Delivery: EPA Docket Center, EPA West Room 3334, 1301 Constitution 

Avenue, NW, Washington, DC 20004, Attention Docket ID No. EPA-HQ-OW2009-0596. Such deliveries are only accepted during the Docket’s normal hours 

of operation, and special arrangements should be made for deliveries of boxed 

information.

Instructions: Direct your comments to Docket ID No. EPA-HQ-OW-2009-0596. EPA’s 

policy is that all comments received will be included in the public docket without change 

and may be made available online at www.regulations.gov, including any personal 

information provided, unless the comment includes information claimed to be 

Confidential Business Information (CBI) or other information whose disclosure is
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restricted by statute. Do not submit information that you consider to be CBI or otherwise 

protected through www.regulations.gov or e-mail. The www.regulations.gov Web site is 

an “anonymous access” system, which means EPA will not know your identity or contact 

information unless you provide it in the body of your comment. If you submit an 

electronic comment, EPA recommends that you include your name and other contact 

information in the body of your comment and with any disk or CD-ROM you submit. If 

EPA cannot read your comment due to technical difficulties and cannot contact you for 

clarification, EPA may not be able to consider your comment. Electronic files should 

avoid the use of special characters, any form of encryption, and be free of any defects or 

viruses. For additional information about EPA’s public docket visit the EPA Docket 

Center homepage at http://www.epa.gov/epahome/dockets.htm. 

Docket: All documents in the docket are listed in the www.regulations.gov index.

Although listed in the index, some information is not publicly available, e.g., CBI or 

other information whose disclosure is restricted by statute. Certain other material, such as 

copyrighted material, will be publicly available only in hard copy. Publicly available 

docket materials are available either electronically in www.regulations.gov or in hard 

copy at a docket facility. The Office of Water (OW) Docket Center is open from 8:30

a.m. until 4:30 p.m., Monday through Friday, excluding legal holidays. The OW Docket 

Center telephone number is (202) 566-2426, and the Docket address is OW Docket, EPA 

West, Room 3334, 1301 Constitution Avenue, NW, Washington, DC 20004. The Public 

Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 

legal holidays. The telephone number for the Public Reading Room is (202) 566-1744.
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FOR FURTHER INFORMATION CONTACT: For information concerning this 

rulemaking, contact Mario Sengco, U.S. EPA Headquarters, Office of Water, Mailcode: 

4305T, 1200 Pennsylvania Avenue, NW, Washington, DC 20460; telephone numbers: 

202-566-2676 or 202-564-1649; fax number: 202-566-9981; email address: 

sengco.mario@epa.gov.

SUPPLEMENTARY INFORMATION: This supplementary information section is 

organized as follows: 

Table of Contents

I. General Information

A. Executive Summary

B. Which Water Bodies Are Affected By This Rule?

C. What Entities May Be Affected By This Rule?

D. How Can I Get Copies of This Document and Other Related Information?

II. Background

A. Nitrogen and Phosphorus Pollution in the United States and the State of 

Florida

B. Statutory and Regulatory Background

C. Water Quality Criteria

D. EPA Determination Regarding Florida and EPA’s Rulemaking

E. EPA Promulgation of the Final Rule and Subsequent Litigation

 F. Florida Adoption of Numeric Nutrient Criteria and EPA Approval
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III. Numeric Criteria for Flowing Waters and Downstream Protection of 

Lakes in the State of Florida

A. Introduction

B. EPA Derivation of Numeric Nutrient Criteria for Streams

C. Reference Condition Approach for Developing Numeric Nutrient Criteria 

for Streams

D. Proposed Numeric Criteria for the State of Florida’s Streams

E. Proposed Numeric Criteria to Ensure the Downstream Protection of the 

State of Florida’s Lakes

E.F. Applicability of Criteria When Final

IV. Under What Conditions Will Federal Standards Be Either Not Finalized or 

Withdrawn?

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 

Order 13563: Improving Regulation and Regulatory Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132 (Federalism)

F. Executive Order 13175 (Consultation and Coordination with Indian Tribal 

Governments)

G. Executive Order 13045 (Protection of Children From Environmental 

Health and Safety Risks)
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H. Executive Order 13211 (Actions That Significantly Affect Energy Supply, 

Distribution, or Use)

I. National Technology Transfer Advancement Act of 1995

J. Executive Order 12898 (Federal Actions To Address Environmental 

Justice in Minority Populations and Low-Income Populations)

I. General Information

A. Executive Summary

Florida is known for its abundant and aesthetically beautiful natural resources, in 

particular its water resources. Florida’s water resources are very important to its 

economy, for example, its $6.5 billion freshwater fishing industry.1 However, nitrogen

and phosphorus pollution has contributed to severe water quality degradation in the State 

of Florida. In the most recent Florida Department of Environmental Protection (FDEP) 

water quality assessment report, the Integrated Water Quality Assessment for Florida:

2012 305(b) Report and 303(d) List Update2, FDEP describes widespread water quality 

impairment in Florida due to nitrogen and phosphorus pollution. FDEP’s 2012 report 

identifies approximately 1,918 miles of rivers and streams (about 14 percent of assessed 

river and stream miles), 378,435 acres of lakes (about 31 percent of assessed lake acres), 

754 square miles (482,560 acres) of estuaries (about 14 percent of assessed estuarine 

area) and 102 square miles (65,280 acres) of coastal waters (about 1.6 percent of assessed 

 1 Florida Fish and Wildlife Conservation Commission. 2010. The economic impact of freshwater fishing in 

Florida. 

<http://www.myfwc.com/CONSERVATION/Conservation_ValueofConservation_EconFreshwaterImpact.

htm.>. Accessed August 2010. 2 FDEP. 2012. Integrated Water Quality Assessment for Florida: 2012 305(b) Report and 303(d) List 

Update. (May 2012). Florida Department of Environmental Protection, Division of Environmental 

Assessment and Restoration, Tallahassee, FL. 

<http://www.dep.state.fl.us/water/docs/2012_integrated_report.pdf>. Accessed August 2012.
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coastal waters) as impaired by nutrients. Despite FDEP's intensive efforts to diagnose, 

evaluate and address nitrogen and phosphorus pollution, substantial and widespread 

water quality degradation from nitrogen and phosphorus pollution has continued and 

remains a significant problem.

On January 14, 2009, EPA determined under Clean Water Act (CWA) section 

303(c)(4)(B) that new or revised water quality standards (WQS) in the form of numeric

water quality criteria are necessary to protect the designated uses from nitrogen and 

phosphorus pollution that Florida has set for its Class I and Class III waters.

3 The Agency 

considered 1) the State's documented unique and threatened ecosystems, 2) the large 

number of impaired waters due to existing nitrogen and phosphorus pollution, and 3) the 

challenge associated with growing nitrogen and phosphorus pollution associated with 

expanding urbanization, continued agricultural development, and a significantly 

increasing population that the U.S. Census estimates is expected to grow over 75% 

between 2000 and 2030.4 EPA also reviewed the State's regulatory accountability system, 

which represents a synthesis of both technology-based standards and point source control 

authority, as well as authority to establish enforceable controls for nonpoint source 

activities.

In December 2009, EPA entered into a Consent Decree with Florida Wildlife 

Federation, Sierra Club, Conservancy of Southwest Florida, Environmental 

Confederation of Southwest Florida, and St. Johns Riverkeeper, which established a 

schedule for EPA to propose and promulgate numeric nutrient criteria for Florida’s lakes, 

 3 Class I is designated for potable water supplies. Class III is designated for recreation, propagation and 

maintenance of a healthy, well-balanced population of fish and wildlife. F.A.C. Section 62-302.400 4 U.S. Census Bureau, Population Division, Interim State Population Projections, 2005.

<http://www.census.gov/population/projections/SummaryTabA1.pdf>.
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springs, flowing waters, estuaries, and coastal waters, as well as downstream protection 

values (DPVs) to protect downstream lakes and estuaries. The Consent Decree provided 

that if Florida submitted and EPA approved numeric nutrient criteria for the relevant 

water bodies before the dates outlined in the schedule, EPA would no longer be obligated 

to propose or promulgate criteria for those water bodies.

On December 6, 2010 (75 FR 75762), EPA’s final rule5 was published in the 

Federal Register and codified at 40 CFR §131.43. The final rule established numeric 

nutrient criteria, or numeric limits on the amount of nitrogen and phosphorus allowed in 

Florida's waters (i.e., lakes, streams and springs) while still protecting applicable 

designated uses.

Following the rule’s publication, EPA soon received 12 challenges from a range 

of plaintiffs that included environmental groups, the State Department of Agriculture, the 

South Florida Water Management District and several industry/discharger groups. The 

challenges alleged that EPA’s determination and final rule were arbitrary, capricious, an 

abuse of discretion, and not in accordance with the law. The U.S. District Court for the 

Northern District of Florida consolidated the suits and held oral argument on January 9, 

2012.

On February 18, 2012, the court issued its ruling.

6 While upholding EPA’s 

determination and much of its rule, the court invalidated EPA's numeric nutrient criteria

for Florida's streams because it found that EPA had either “aimed for the wrong target” or 

not sufficiently explained what it did in aiming for the right target. The court observed 

 5 Federal Register, Vol. 75, No. 233, 75762, December 6, 2010. Water Quality Standards for the State of 

Florida’s Lakes and Flowing Waters. 6 Florida Wildlife Federation, Inc., et. al. v. Jackson, Case 4:08-cv-00324-RH-WCS, Doc. 351 (N.D.Fla. 

February 18, 2012).

Comment [MS2]: See additional preceding 

paragraph that provides more information.
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that Florida's existing narrative criterion states, in relevant part, that "nutrient 

concentrations of a body of water [must not] be altered so as to cause an imbalance in 

natural populations of aquatic flora or fauna." Fla. Admin. Code r. 62-302.530(47)(b).

Based on that narrative criterion, as implemented by FDEP, the court found that the 

correct target would be to avoid any harmful increase in nutrient levels, as opposed to any

increase in nutrient levels. The court found that EPA had apparently derived stream 

numeric nutrient criteria to prevent any increase in nutrient levels, and had thus aimed at 

the wrong target. If EPA had derived stream numeric nutrient criteria to prevent any 

harmful increase, the court found that EPA had not provided a sufficient explanation for 

its action. For similar reasons, the court also invalidated EPA's default DPV for streams 

where the downstream lake is attaining its lake numeric nutrient criteria. Hence, the court 

ordered EPA to either “sign for publication a proposed rule, or sign for publication a final 

rule, that sets numeric nutrient criteria for Florida streams” by May 21, 2012. As to the 

DPV where a lake is attaining its lake numeric criteria, the same order applies unless 

EPA files a notice by May 21, 2012 that it has decided not to propose or adopt such DPV, 

with an explanation of that decision.

On May 30, 2012, the court granted EPA’s request to extend the deadline for 

signing a proposed rule to November 30, 2012. The court also ordered that the final rule 

must be signed for publication by August 31, 2013.

For this proposal, EPA is re-proposing the same numeric nutrient criteria for TN 

and TP published in EPA’s final rule on December 6, 2010 (75 FR 75762), with further 

explanation on how the proposed streams criteria will ensure the protection of Florida’s 

Class I and III designated uses and how the criteria are an appropriate translation of 

Comment [MS3]: See comment MS4

Comment [MS4]: Regarding the comments 

received from the USDA, EPA reviewed and 

considered them, but respectfully disagrees. EPA 

firmly believes in the use of the reference condition 

approach and its selection of the 90th percentile 

values (75th percentile in the West Central region) as 

the appropriate total nitrogen and total phosphorus 

criteria that protect the applicable designated uses 

and translate Florida’s narrative nutrient criterion for 

the purposes of the CWA. The use of the reference 

condition approach was evaluated and upheld by the 

U.S. District Court for Northern District of Florida. 

The choice of the percentile values were supported 

by multiple lines of evidence, including the peerreviewed scientific literature and a review of data 

from Florida showing harmful adverse impacts at 

higher concentrations provided by the Florida 

Department of Environmental Protection. Given 

EPA's analysis, the Agency is confident that it has 

met the court's order and the requirement of the 

CWA.

Comment [MS5]: Removed highlight.
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Florida’s narrative nutrient criterion. This proposal also is consistent with the objective 

and requirements of the CWA and EPA’s implementing regulations at 40 CFR part 131.

EPA is also proposing default approaches available for use when modeling cannot be 

performed to derive DPVs that will ensure the attainment and maintenance of the 

numeric nutrient criteria that protect the designated uses of Florida’s downstream lakes.

These default approaches are applicable to streams that flow downstream into unimpaired 

lakes, but could also be used for streams that flow downstream into impaired lakes.

On June 13, 2012, FDEP submitted new and revised water quality standards for 

review by the EPA pursuant to section 303(c) of the CWA. These new and revised water 

quality standards are set out primarily in Rule 62-302 of the Florida Administrative Code 

(F.A.C.) [Surface Water Quality Standards]. FDEP also submitted amendments to Rule 

62-303, F.A.C. [Identification of Impaired Surface Waters], which sets out Florida’s 

methodology for assessing whether waters are attaining State water quality standards. On 

November 30, 2012, EPA approved the provisions of these rules submitted for review 

that constitute new or revised water quality standards (hereafter referred to as the “newlyapproved state water quality standards”).

Among the newly-approved state water quality standards are numeric criteria for 

nutrients that apply to a set of streams, as that term is specifically defined in the newlyapproved state water quality standards. Under the Consent Decree, EPA is relieved of its 

obligation to propose numeric criteria for nutrients for any waters for which FDEP 

submits and EPA approves new or revised water quality standards before EPA proposes. 

Thus, under normal circumstances, EPA would be clearly relieved of its obligation to 
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propose numeric criteria for nutrients in streams Florida covered in its newly-approved 

state water quality standards.

However, another provision included in Florida’s Rule, specifically subsection 

62-302.531(9), F.A.C., casts some doubt as to whether the newly approved state water 

quality standards will go into effect if EPA proposes and promulgates numeric nutrient 

criteria for streams not covered by the newly-approved State water quality standards.

Therefore, it is unclear whether an EPA proposal to “gap fill”, or establish numeric 

criteria for nutrients for Florida streams that FDEP does not cover in its Rule, would 

trigger 62-302.531(9), F.A.C. and result in Florida’s streams criteria not taking effect.

In addition, due to a recent administrative challenged filed in the State of Florida 

Department of Administrative Hearings, there is uncertainty as to whether FDEP will be 

able to implement its newly approved state water quality standards consistent with 

FDEP’s “Implementation of Florida’s Numeric Nutrient Standards” (Implementation 

Document). EPA approved Florida’s new or revised water quality standards based on the 

Agency’s understanding that FDEP will implement the streams criteria as provided in its 

Implementation Document. Thus, EPA approved portions of Florida’s new or revised 

water quality standards subject to the State being able to implement them as provided in 

its Implementation Document. If, as a result of legal challenge, FDEP is unable to 

implement its Rule as provided in its Implementation Document, EPA would intend to 

revisit portions of its November 30, 2012 approval of Florida’s new or revised water 

quality standards. EPA has therefore reserved its authority to withdraw or modify 

portions of that approval. 

Comment [MS6]: Corrected throughout.

Comment [MS7]: Accepted comments and edits.

Comment [MS8]: Accepted strikeout

Comment [MS9]: Accepted strikeout.
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In light of the above, EPA seeks comment on finalizing a rule that applies EPA’s 

streams criteria to streams meeting EPA’s definition of “stream” that are not covered 

under Florida’s numeric interpretation of narrative nutrient criteria at 62-302.531(2)(c), 

F.A.C. This would serve to fill gaps in coverage if Florida’s streams criteria are in effect, 

or apply to all streams if Florida’s streams criteria are not in effect for any reason, 

including those mentioned above.

Finally, as described in EPA’s November 30, 2012 approval of Florida’s new or 

revised water quality standards, while EPA believes that the provisions addressing 

downstream protection will provide for quantitative approaches to ensure the attainment 

and maintenance of downstream waters consistent with 40 CFR 131.10(b), the provisions 

themselves, however, do not consist of numeric values. Because EPA is currently subject 

to a Consent Decree deadline to sign a rule proposing numeric downstream protection 

values (DPVs) for Florida by November 30, 2012, EPA is proposing numeric DPVs to 

comply with the Consent Decree. However, EPA has amended its January 2009 

determination to specify that numeric criteria for downstream protection are not 

necessary and that quantitative approaches designed to ensure the attainment and 

maintenance of downstream water quality standards, such as those established by Florida, 

are sufficient to meet CWA requirements. As such, EPA will ask the court to modify the 

Consent Decree consistent with the Agency’s amended determination, i.e., to not require 

EPA to promulgate numeric DPVs for Florida. Accordingly, EPA approved the State’s 

downstream protection provisions subject to the district court modifying the Consent 

Decree to not require EPA to promulgate numeric DPVs for Florida. If the district court 

agrees to so modify the Consent Decree, EPA will not promulgate numeric DPVs for 
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Florida. However, if the district court declines to so modify the Consent Decree, EPA 

would intend to promulgate numeric DPVs for Florida and would also expect to revisit its 

November 30, 2012 approval of the State Rule’s downstream protection provisions to 

modify or withdraw its approval. Therefore, EPA has also reserved its authority to do so

in its approval document.

A full description of all of EPA’s recent actions on Florida numeric nutrient 

criteria and related implications for EPA’s own rules can be found at 

http://water.epa.gov/lawsregs/rulesregs/florida_index.cfm.

B. Which Water Bodies Are Affected By This Rule?

The criteria in this proposed rulemaking apply to a group of inland waters of the 

United States within Florida. Specifically, these criteria apply to flowing waters (i.e., 

streams) located outside of the South Florida Region that are designated as either Class I 

or Class III not covered by the State of Florida’s Rule.

7 EPA notes if Florida’s Rule will 

not take effect due to subsection 62-302.531(9), F.A.C., EPA would expect to finalize the 

criteria in this proposed rulemaking for all flowing waters (i.e., streams) located outside 

of the South Florida Region that are designated as either Class I or Class III. EPA solicits 

comment on this potential outcome.

Class I and Class III streams share water quality criteria established to “protect 

recreation and the propagation and maintenance of a healthy, well-balanced population of 

fish and wildlife” pursuant to Subsection 62-302.400(4), F.A.C.8 “Stream”, as defined at 

 7 For purposes of this rule, EPA has distinguished South Florida as those areas south of Lake Okeechobee 

and the Caloosahatchee River watershed to the west of Lake Okeechobee and the St. Lucie watershed to the 

east of Lake Okeechobee, hereinafter referred to as the South Florida Region. 8 Class I waters also include an applicable nitrate limit of 10 mg/L and nitrite limit of 1 mg/L for the 
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40 CFR §131.43(b)(12) means a free-flowing, predominantly fresh surface water in a 

defined channel, and includes rivers, creeks, branches, canals, freshwater sloughs, and 

other similar water bodies. EPA notes that as defined at 40 CFR § 131.43(b)(8) and 

consistent with Section 62-302.200, F.A.C., “predominantly fresh waters” means surface 

waters in which the chloride concentration at the surface is less than 1,500 milligrams per 

liter (mg/L).

The definition of stream in the approved water quality standards for purposes of 

applying the numeric interpretation of the narrative nutrient criterion to streams is less 

inclusive than as defined at 40 CFR §131.43(b)(12). Florida’s stream definition for 

purposes of applying the numeric interpretation of the narrative nutrient criterion (see 

Subsection 62-302.200(36), F.A.C) specifically excludes non-perennial water segments;

tidally influenced segments; and ditches, canals and other conveyances that are manmade or predominantly channelized or physically altered, are used primarily for water 

management purposes, and have marginal or poor stream habitat components. Inland 

flowing waters that meet EPA’s definition of stream yet do not meet Florida’s definition 

of stream for purposes of applying the numeric interpretation of the narrative nutrient 

criterion are designated Class I or Class III waters in Florida water quality standards. If 

they are not Class I or Class III waters, then this proposed rule would not apply. This 

rule does not apply to wetlands, including non-perennial stream segments that function as 

wetlands because of fluctuating hydrologic conditions that typically result in the 

dominance of wetland taxa.

 

protection of human health in drinking water supplies. The nitrate limit applies at the entry point to the 

distribution system (i.e., after any treatment); see Chapter 62-550, F.A.C., for additional details.
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C. What Entities May Be Affected By This Rule?

Citizens concerned with water quality in Florida may be interested in this 

rulemaking. Entities discharging nitrogen or phosphorus to flowing waters of Florida 

could be indirectly affected by this rulemaking because WQS are used in determining 

National Pollutant Discharge Elimination System (NPDES) permit limits. Categories and 

entities that may ultimately be affected include:

Category Examples of potentially affected entities

Industry Industries discharging nitrogen and phosphorus to flowing 

waters in the State of Florida.

Municipalities Publicly-owned treatment works discharging nitrogen and 

phosphorus to flowing waters in the State of Florida.

Stormwater 

Management Districts 

Entities responsible for managing stormwater runoff in 

Florida.

This table is not intended to be exhaustive, but rather provides a guide for 

entities that may be directly or indirectly affected by this action. This table lists the types 

of entities of which EPA is now aware that potentially could be affected by this action.

Other types of entities not listed in the table, such as nonpoint source contributors to 

nitrogen and phosphorus pollution in Florida’s waters may be affected through 

implementation of Florida’s water quality standards program (i.e., through Basin 

Management Action Plans (BMAPs)). Any parties or entities conducting activities within 

watersheds of the Florida waters covered by this rule, or who rely on, depend upon, 

influence, or contribute to the water quality of flowing waters of Florida, may be affected 

by this rule. To determine whether your facility or activities may be affected by this 

action, you should carefully examine the language in this proposal. If you have questions 

regarding the applicability of this action to a particular entity, consult the person listed in 

the preceding FOR FURTHER INFORMATION CONTACT section.

Comment [MS10]: No change made. EPA only 

regulates point-sources under the CWA.
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D. How Can I Get Copies of This Document and Other Related Information?

1. Docket. EPA has established an official public docket for this action under 

Docket Id. No. EPA-HQ-OW-2009-0596. The official public docket consists of the 

document specifically referenced in this action, any public comments received, and other

information related to this action. Although a part of the official docket, the public docket 

does not include Confidential Business Information (CBI) or other information whose 

disclosure is restricted by statute. The official public docket is the collection of materials 

that is available for public viewing at the OW Docket, EPA West, Room 3334, 1301 

Constitution Ave., NW, Washington, DC 20004. This Docket Facility is open from 8:30 

a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The OW Docket 

telephone number is 202-566-2426. A reasonable fee will be charged for copies.

2. Electronic Access. You may access this Federal Register document 

electronically through the EPA Internet under the “Federal Register” listings at

http://www.regulations.gov. An electronic version of the public docket is available 

through EPA's electronic public docket and comment system, EPA Dockets. You may 

use EPA Dockets at http://www.regulations.gov to view public comments, access the 

index listing of the contents of the official public docket, and to access those documents 

in the public docket that are available electronically. For additional information about 

EPA's public docket, visit the EPA Docket Center homepage at 

http://www.epa.gov/epahome/dockets.htm. Although not all docket materials may be 

available electronically, you may still access any of the publicly available docket 

materials through the Docket Facility identified earlier.
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II. Background

A. Nitrogen and Phosphorus Pollution in the United States and the State of Florida

Excess loading of nitrogen and phosphorus compounds9 is one of the most 

prevalent causes of water quality impairment in the United States. Nitrogen and 

phosphorus pollution problems have been recognized for decades in the U.S. For 

example, a 1969 report by the National Academy of Sciences noted that “[t]he pollution 

problem is critical because of increased population, industrial growth, intensification of 

agricultural production, river-basin development, recreational use of waters, and 

domestic and industrial exploitation of shore properties. Accelerated eutrophication 

causes negative changes in plant and animal life – harmful, adverse changes that often 

interfere with use of water, detract from natural beauty, and reduce property values.” 10

Inputs of nitrogen and phosphorus lead to over-enrichment in many of the Nation's waters 

and constitute a widespread, persistent, and growing problem.

11 Nitrogen and phosphorus

pollution in fresh water systems can significantly negatively impact aquatic life and longterm ecosystem health, diversity, and balance.12 More specifically, high nitrogen and 

 9 To be used by living organisms, nitrogen gas must be fixed into its reactive forms; for plants, either nitrate 

or ammonia (Boyd, C.E. 1979. Water Quality in Warmwater Fish Ponds. Auburn University: Alabama 

Agricultural Experiment Station, Auburn, AL). Eutrophication is defined as the natural or artificial addition 

of nitrogen and phosphorus to bodies of water and to the effects of added nitrogen and phosphorus 

(National Academy of Sciences (U.S). 1969. Eutrophication: Causes, Consequences, Correctives. National 

Academy of Sciences, Washington, DC.)

10 National Academy of Sciences (U.S). 1969. Eutrophication: Causes, Consequences, Correctives. 

National Academy of Sciences, Washington, DC. 11 GulfBase. 2009. Bays and Estuaries. http://www.gulfbase.org/bay/. Accessed April, 2009.; NSTC. 2003. 

An Assessment of Coastal Hypoxia and Eutrophication in U.S. Waters. National Science and Technology 

Council, Committee on Environment and Natural Resources, Washington, DC.

http://coastalscience.noaa.gov/documents/hypoxia.pdf. Accessed July, 2009; USEPA, 2009. National 

Summary of State Information. U.S. Environmental Protection Agency, Washington, D.C., 

http://iaspub.epa.gov/waters10/attains_nation_cy.control. Accessed June, 2009. 12USEPA, 2006. USEPA. 2006b. Wadeable Streams Assessment. EPA 841-B-06-002. U.S. Environmental 

Protection Agency, Washington, DC; Chesapeake Bay Program, 2009. Underwater Bay Grasses.
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phosphorus loadings can result in harmful algal blooms (HABs), reduced spawning 

grounds and nursery habitats, fish kills, and oxygen-starved hypoxic or “dead” zones.

13

Public health concerns related to nitrogen and phosphorus pollution include 

methanoglobanemia due to impaired drinking water sources from high levels of nitrates, 

increase in bladder cancer due to possible formation of disinfection byproducts in 

drinking water, and neurotoxicity and kidney damage due to increased exposure to 

cyanotoxins produced by harmful algae and cyanobacteria.

14,15 Degradation of water 

bodies from nitrogen and phosphorus pollution can result in economic costs. For 

example, given that freshwater fishing in Florida is a significant recreational and tourist 

attraction generating over six billion dollars annually,16 degradation of water quality in 

Florida to the point that sport fishing populations are negatively affected will also 

negatively affect this important part of Florida’s economy. Elevated nitrogen and 

phosphorus levels can occur locally in a stream or ground water, or can accumulate 

downstream leading to degraded lakes, reservoirs, and estuaries where fish and aquatic 

 

http://www.chesapeakebay.net/baygrasses.aspx?menuitem=14621. Accessed July, 2009. 13 NOAA, 2009. Harmful Algal Blooms. National Oceanic and Atmospheric Administration, Silver

Spring, MD. http://oceanservice.noaa.gov/topics/coasts/hab/. Accessed April, 2009; Tomasko et al., 2005.

Spatial and temporal variation in seagrass coverage in Southwest Florida: assessing the relative effects of 

anthropogenic nutrient load reductions and rainfall in four contiguous estuaries. Marine Pollution Bulletin

50: 797-805.; Selman et al., 2008. Eutrophication and Hypoxia in Coastal Areas: A Global Assessment of 

the State of Knowledge. WRI Policy Note No. 1 World Resources Institute, Washington D.C.; Mississippi 

Rive/Gulf of Mexico Watershed Nutrient Task Force, 2008. Gulf Hypoxia Action Plan 2008 for Reducing, 

Mitigating and Controlling Hypoxia in the Northern Gulf of Mexico and Improving Water Quality in the 

Mississippi River Basin. Washington, D.C. 14 Villanueva, C.M. et al., 2006. Bladder Cancer and Exposure to Water Disinfection By-Products through 

Ingestion, Bathing, Showering, and Swimming in Pools. American Journal of Epidemiology 165(2):148-

156.

15 USEPA. 2009. What is in Our Drinking Water?. United States Environmental Protection Agency, Office 

of Research and Development. < http://www.epa.gov/extrmurl/research/process/drinkingwater.html>. 

Accessed December 2009.

16 Florida Fish and Wildlife Conservation Commission. 2010. The economic impact of freshwater fishing in 

Florida. 

<http://www.myfwc.com/CONSERVATION/Conservation_ValueofConservation_EconFreshwaterImpact.

htm>. Accessed August 2010.

Comment [MS11]: This paragraph is all about 

general effects. The next two paragraphs that follow 

talks about effects specific to Florida. EPAs 

justification on the 90th is presented in Section III.

Also, the portions of this rule that were not 

remanded, allows for the development of sitespecific alternative criteria that can be established 

where conditions warrant and it is appropriate. 
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life can no longer survive or spawn and the designated use is no longer supported. For 

additional information on the sources, impacts (e.g., human health, aquatic life, 

environmental) and economic implications of nitrogen and phosphorus pollution, please 

refer to the December 6, 2010 final rule.17

Florida's flat topography causes water to move slowly over the landscape, 

allowing ample opportunity for nitrogen and phosphorus to be transported offsite and 

result in eutrophication. Florida's warm and wet, yet sunny, climate further contributes to 

increased run-off and ideal temperatures for subsequent eutrophication responses.18 As 

outlined in EPA’s January 2009 determination, water quality degradation resulting from 

excess nitrogen and phosphorus loadings is a documented and significant environmental 

issue in Florida. For example, the Florida Department of Environmental Protection 

(FDEP) 2008 Integrated Water Quality Assessment notes: “the close connection between 

surface and ground water, in combination with the pressures of continued population 

growth, accompanying development, and extensive agricultural operations, present 

Florida with a unique set of challenges for managing both water quality and quantity in 

the future. After trending downward for 20 years, phosphorus levels again began moving 

upward in 2000, likely due to the cumulative impacts of nonpoint source pollution 

associated with increased population and development. Increasing pollution from urban 

stormwater and agricultural activities is having other significant effects. In many springs 

across the State, for example, nitrate levels have increased dramatically (two-fold to 

three-fold) over the past 20 years, reflecting the close link between surface and ground 

 17 75 FR 75762, December 6, 2010. Water Quality Standards for the State of Florida’s Lakes and Flowing 

Waters.

18 Perry, W. B. 2008. Everglades restoration and water quality challenges in south Florida. Ecotoxicology

17:569-578. 

Comment [MS12]: See comment MS4

Comment [MS13]: See comment MS4
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water.”19 To clarify current nitrogen and phosphorus pollution conditions in Florida, EPA 

analyzed recent STORET (STOrage and RETrieval) data pulled from Florida’s Impaired 

Waters Rule (IWR),

20 which are the data Florida uses to create its integrated reports, and 

found increasing levels of nitrogen and phosphorus compounds in Florida waters over 12 

years (1996-2008). Florida’s IWR STORET data indicates that levels of total nitrogen 

(i.e., State-wide average) have increased by 20% from 1996 to 2008, and total 

phosphorus levels (i.e., State-wide average) have increased by 40% over the same time 

period.

The combination of the factors reported by FDEP and listed earlier (including 

population increase, climate, stormwater runoff, agriculture, and topography) has 

contributed to significant harmful, adverse effects from nitrogen and phosphorus

pollution (nutrient pollution) to Florida’s waters.21 In the most recent Florida Department 

of Environmental Protection (FDEP) water quality assessment report, the Integrated 

Water Quality Assessment for Florida: 2012 305(b) Report and 303(d) List Update, 

FDEP describes widespread water quality impairment in Florida due to nitrogen and 

phosphorus pollution. FDEP’s 2012 report22 identifies approximately 1,918 miles of 

rivers and streams (about 14 percent of assessed river and stream miles), 378,435 acres of 

lakes (about 31 percent of assessed lake acres), 754 square miles (482,560 acres) of 

estuaries (about 14 percent of assessed estuarine area) and 102 square miles (65,280 

 19 FDEP. 2008. Integrated Water Quality Assessment for Florida: 2008 305(b) Report and 303(d) List 

Update.

20 IWR Run 40. Updated through February 2010. 21 FDEP. 2008. Integrated Water Quality Assessment for Florida: 2008 305(b) Report and 303(d) List 

Update.

22 FDEP. 2012. Integrated Water Quality Assessment for Florida: 2012 305(b) Report and 303(d) List 

Update. (May 2012). Florida Department of Environmental Protection, Division of Environmental 

Assessment and Restoration, Tallahassee, FL. 

<http://www.dep.state.fl.us/water/docs/2012_integrated_report.pdf>. Accessed August 2012
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acres) of coastal waters (about 1.6 percent of assessed coastal waters) as impaired by

nutrients. In addition, the same report indicates that 1,108 miles of rivers and streams 

(about 8 percent of assessed river and stream miles) and 107 square miles (68,480 acres) 

of lakes (about 5 percent of assessed lake square miles) are impaired due to nutrient 

pollution.

For additional information regarding the prevalence of nutrient pollution in 

various water bodies in Florida and negative implications of nutrient pollution in State 

waters, please refer to the December 6, 2010 final rule.

23

B. Statutory and Regulatory Background

Section 303(c) of the CWA (33 U.S.C. 1313(c)) directs states to adopt WQS for 

their navigable waters. Section 303(c)(2)(A) and EPA's implementing regulations at 40 

CFR part 131 require, among other things, that state WQS include the designated use or 

uses to be made of the waters and criteria that protect those uses. EPA regulations at 40 

CFR §131.11(a)(1) provide that states shall "adopt those water quality criteria that protect 

the designated use" and that such criteria "must be based on sound scientific rationale and 

must contain sufficient parameters or constituents to protect the designated use." In 

addition, 40 CFR §131.10(b) provides that "[i]n designating uses of a waterbody and the 

appropriate criteria for those uses, the state shall take into consideration the water quality 

standards of downstream waters and ensure that its water quality standards provide for 

the attainment and maintenance of the water quality standards of downstream waters.”

 23 75 FR 75762, December 6, 2010. Water Quality Standards for the State of Florida’s Lakes and Flowing 

Waters.
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States are required to review their WQS at least once every three years and, if 

appropriate, revise or adopt new standards. (See CWA section 303(c)(1)). Any new or 

revised WQS must be submitted to EPA for review and approval or disapproval. (See

CWA section 303(c)(2)(A) and (c)(3)). In addition, CWA section 303(c)(4)(B) authorizes 

the Administrator to determine, even in the absence of a state submission, that a new or 

revised standard is needed to meet CWA requirements. The EPA approved the State of 

Florida’s rules for streams on November 30, 2012. The criteria proposed in this 

rulemaking protect the uses designated by the State of Florida and implement Florida’s 

narrative nutrient provision at Subsection 62-302-530(47)(b), F.A.C. for the purposes of 

the CWA, into numeric values that apply to flowing waters not covered by the State’s 

Rule outside of the South Florida Region and DPVs to ensure the attainment and 

maintenance of the water quality standards of downstream lakes.

24 For a thorough review 

of the statutory and regulatory background for this proposed rule, refer to the December 

6, 2010 final rule.

C. Water Quality Criteria

Under CWA section 304(a), EPA periodically publishes criteria 

recommendations (guidance) for use by states in setting water quality criteria for 

particular parameters to protect recreational and aquatic life uses of waters. Where EPA 

has published recommended criteria, states have the option of adopting water quality 

criteria based on EPA’s CWA section 304(a) criteria guidance, section 304(a) criteria 

guidance modified to reflect site-specific conditions, or other scientifically defensible 

 24 The criteria finalized in this rulemaking do not address or implement Florida’s narrative nutrient 

provision at Subsection 62-302.530(47)(a), F.A.C. Subsection 62-302.530(47)(a), F.A.C., remains in place 

as an applicable WQS for CWA purposes.

Comment [MS14]: Accepted comment and edits

Comment [MS15]: Accepted strikeout
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methods. (See 40 CFR §131.11(b)(1)). For nutrient pollution, EPA has published under 

CWA section 304(a) a series of peer-reviewed, national technical approaches and 

methods regarding the development of numeric nutrient criteria for lakes and reservoirs,25

rivers and streams,26 and estuarine and coastal marine waters.27 For an overview of 

EPA’s recommended approaches for deriving numeric nutrient criteria in Florida lakes 

and flowing waters, please refer to the December 6, 2010 final rule.

28 EPA believes that 

numeric nutrient criteria will expedite and facilitate the effective implementation of 

Florida’s existing point and non-point source water quality programs under the CWA in 

terms of timely water quality assessments, TMDL development, NPDES permit issuance 

and, where needed, Basin Management Action Plans (BMAPs) to address nitrogen and 

phosphorus pollution.

D. EPA Determination Regarding Florida and EPA’s Rulemaking

On January 14, 2009, EPA determined under Clean Water Act (CWA) section 

303(c)(4)(B) that new or revised water quality standards (WQS) in the form of numeric

water quality criteria are necessary to protect the designated uses from nitrogen and 

phosphorus pollution that Florida has set for its Class I and Class III waters. EPA’s 

determination is available at the following website:

http://www.epa.gov/waterscience/standards/rules/fl-determination.htm

 25 USEPA. 2000a. Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs. EPA-822-B-00-

001. U.S. Environmental Protection Agency, Office of Water, Washington, DC.

26 USEPA. 2000b. Nutrient Criteria Technical Guidance Manual:Rivers and Streams. EPA-822-B-00-002.

U.S. Environmental Protection Agency, Office of Water, Washington, DC.

27 USEPA. 2001. Nutrient Criteria Technical Manual: Estuarine and Coastal Marine Waters. EPA-822-B01-003. U.S. Environmental Protection Agency, Office of Water, Washington, DC. 28 75 FR, 75762, December 6, 2010. Water Quality Standards for the State of Florida’s Lakes and Flowing 

Waters.
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On August 19, 2009, EPA entered into a Consent Decree with Florida Wildlife 

Federation, Sierra Club, Conservancy of Southwest Florida, Environmental 

Confederation of Southwest Florida, and St. Johns Riverkeeper, committing to the 

schedule stated in EPA’s January 14, 2009 determination to propose numeric nutrient 

criteria for lakes and flowing waters in Florida by January 14, 2010, and for Florida's 

estuarine and coastal waters by January 14, 2011, unless the State submits and EPA 

approves new or revised water quality standards pursuant to section 303(c)(3).

29 The 

Consent Decree also required that EPA sign a notice of final rulemaking for the 

respective proposals by October 15, 2010, for lakes and flowing waters, and by October

15, 2011, for estuarine and coastal waters, unless the State submits and EPA approves 

new or revised water quality standards pursuant to section 303(c)(3).. The Consent 

Decree, which became effective on December 30, 2009, also included a commitment to

develop numeric DPVs to protect downstream lakes and estuaries. To review the bases 

for EPA’s determination, and the information it considered in making its determination, 

please see the December 6, 2010 final rule.

E. EPA Promulgation of the Final Rule and Subsequent Litigation

In accordance with the January 14, 2009 determination, the August 19, 2009 

Consent Decree, and subsequent revisions to that Consent Decree, EPA signed a notice of 

final rulemaking establishing numeric nutrient criteria for streams, lakes, and springs in 

the State of Florida30 on November 14, 2010. As stated in the final rule at 40 CFR 

 29 Florida Wildlife Federation, Inc., et. al. v. Jackson, Case 4:08-cv-00324-RH-WCS, Doc. 90-2 (N.D.Fla. 

August 25, 2009). 

30 For purposes of this rule, EPA has distinguished South Florida as those areas south of Lake Okeechobee 

and the Caloosahatchee River watershed to the west of Lake Okeechobee and the St. Lucie watershed to the 

Comment [MS16]: Accepted addition

Comment [MS17]: Accepted addition

Comment [MS18]: This sentence added in 

response to OMB comment to provide more

information.

Comment [MS19]: See additional sentence 

above.
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§131.43(f), the rule was scheduled to take effect on March 6, 2012, except for the sitespecific alternative criteria (SSAC) provision at 40 CFR §131.43(e), which took effect on 

February 4, 2011. EPA selected the March 6, 2012 effective date for the criteria part of 

the rule to allow time for EPA to work with stakeholders and the Florida Department of 

Environmental Protection (FDEP) on important implementation issues, to help the public 

and all affected parties better understand the final numeric nutrient criteria and the basis 

for those criteria, and for EPA to engage and support, in full partnership with FDEP, the 

general public, stakeholders, local governments, and sectors of the regulated community 

across the State in a process of public outreach education, discussion, and constructive 

planning. 75 FR 75787. The effective date was subsequently extended (77 FR 13497 and 

77 FR 39949) such that the current effective date of the rule is January 6, 2013. In 

addition to this proposal, EPA has proposed to stay the December 6, 2010 final rule (75 

FR 75762) to November 15, 2013 (See 

http://water.epa.gov/lawsregs/rulesregs/florida_inland.cfm)

Following the publication of the rule in the Federal Register on December 6, 

2010, 12 cases were filed in the U.S. District Court for the Northern District of Florida 

challenging the rule. The cases, consolidated before Judge Robert Hinkle in the 

Tallahassee Division of the Northern District, were filed by environmental groups, 

Florida’s State Department of Agriculture, the South Florida Water Management District, 

and various industry/discharger groups. The challenges alleged that EPA’s determination 

and final rule were arbitrary, capricious, an abuse of discretion, and not in accordance 

 

east of Lake Okeechobee, hereinafter referred to as the South Florida Region. Numeric criteria applicable 

to flowing waters in the South Florida Region will be addressed in the second phase of EPA’s rulemaking 

regarding the establishment of estuarine and coastal numeric criteria. (Please refer to Section I.B for a 

discussion of the water bodies affected by this rule).
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with the law for a variety of reasons. Oral argument in the case was held on January 9, 

2012 before Judge Hinkle.

On February 18, 2012, the Court upheld EPA’s January 2009 determination and 

the final numeric nutrient criteria for Florida’s lakes and springs, as well as the sitespecific alternative criteria (SSAC) provisions and the provisions for calculating DPVs 

using either modeling or a default option for an impaired lake that is not attaining its 

numeric nutrient criteria. See February 18, 2012 Court Order. For EPA’s numeric 

nutrient criteria for flowing waters (i.e., streams) and the default option to calculate DPVs 

for unimpaired lakes based on ambient stream nutrient concentrations at the point of 

entry to the lake, the Court found that EPA had not provided sufficient information in its 

final rule explaining why or how the criteria or DPV protect against harmful increases, as 

opposed to any increase, in nutrients. The Court observed that EPA’s scientific approach 

to deriving streams criteria (i.e., the reference condition approach), including the 

criteria’s duration and frequency components, “are matters of scientific judgment on 

which the rule would survive arbitrary-or-capricious review.” Order at 63. The Court also 

found, however, that EPA had not explained in sufficient detail how the streams criteria 

would prevent a “harmful increase in a nutrient level”. Order at 63. In addition, the Court 

found that EPA had not explained in sufficient detail how exceedances of the default 

DPV for unimpaired lakes would lead to “harmful effects” in the downstream lake. Order 

at 63. Thus, the Court invalidated these two aspects of EPA’s final rule and remanded 

them to the Agency for further action.

The Court ordered that the upheld portions of EPA’s final rule be codified at 40 

CFR §131.43 with the exceptions of the streams criteria and the default DPV for 

Comment [MS20]: See comment MS4
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unimpaired lakes. Order at 85. For the exceptions, the Court ordered: “By May 21, 2012, 

the Administrator must sign for publication a proposed rule, or sign for publication a final 

rule, that sets numeric nutrient criteria for Florida streams that are not in the South 

Florida region. By May 21, 2012, the Administrator must sign for publication a proposed 

rule, or sign for publication a final rule, that sets default downstream-protection criteria 

for unimpaired lakes, unless by that date the Administrator has filed a notice that she has 

decided not to propose or adopt such criteria, together with an explanation of the 

decision.” Order at 85. After the May 21, 2012 deadline was jointly extended by the 

parties to June 4, 2012, on May 30, 2012, the court granted EPA’s request to further 

extend the deadline for signing a proposed rule to November 30, 2012. The court also 

ordered that EPA must sign a notice of final rulemaking by August 31, 2013. In 

accordance with the Court’s Order, EPA is proposing numeric nutrient criteria for 

Florida’s streams and three default approaches for deriving DPVs for unimpaired lakes 

(and impaired lakes) with this proposed rule.

F. Florida Adoption of Numeric Nutrient Criteria and EPA Approval

On June 13, 2012, the Florida Department of Environmental Protection (FDEP)

submitted new and revised water quality standards for review by the EPA pursuant to 

section 303(c) of the CWA. These new and revised water quality standards are set out 

primarily in Rule 62-302 of the Florida Administrative Code (F.A.C.) [Surface Water 

Quality Standards]. FDEP also submitted amendments to Rule 62-303, F.A.C. 

[Identification of Impaired Surface Waters], which sets out Florida’s methodology for 

assessing whether waters are attaining State water quality standards. On November 30, 
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2012, EPA approved the provisions of these rules submitted for review that constitute 

new or revised water quality standards (referred to in this preamble as the “newly 

approved state water quality standards”). These newly-approved state water quality 

standards include provisions that set forth numeric interpretations of the narrative nutrient 

criterion in paragraph 62-302.530(47)(b), F.A.C. for streams (Subsection 62-

302.531(2)(c), F.A.C) that meet a specific definition (Section 62-302.200(36), F.A.C.).

The numeric interpretation for stream protection in Florida’s newly approved 

water quality standards uses biological information in combination with nutrient 

thresholds. Stream protection is achieved if (1) various measures of aquatic plant growth 

(e.g., “floral metrics”) indicate “no imbalances” and EITHER (2) measures of the faunal 

stream community health called the Stream Condition Index (SCI) is above a certain 

threshold OR (3) the nutrient thresholds for total phosphorus (TP) and total nitrogen (TN) 

for the relevant region are met. The nutrient thresholds in Florida’s newly approved water 

quality standards are identical to the “stand-alone” streams criteria in this proposed rule. 

EPA’s approval document is included in the set of materials provided in the docket for 

this proposed rule (Docket number EPA-HQ-OW-2009-0596, www.regulations.gov).

III. Numeric Criteria for Flowing Waters and Downstream Protection of Lakes in 

the State of Florida 

A. Introduction

In the December 2010 final rule, using the reference condition approach, EPA 

promulgated numeric nutrient criteria for Florida’s streams based on the concentrations of 

total nitrogen (TN) and total phosphorus (TP) observed in a sample of least-disturbed 

Comment [MS21]: See comment MS4
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streams. EPA set the numeric nutrient criteria so that the annual average concentrations of 

TN and TP most often observed in reference sites that are known to support the 

designated uses would not exceed the criteria. The court, however, found that EPA failed 

to explain “how the 90% mark correlates with a harmful increase in nutrients” (as 

opposed to any increase in nutrients). Order at 65. The court noted that it “may well be 

that there is a sufficient correlation” that above the criteria concentrations “harmful 

change is likely.” Order at 66. However, the court found that EPA had not adequately 

explained its decision and remanded to EPA for further action.31

In response to the court’s remand, EPA has conducted a comprehensive review of 

available scientific data and information to more fully document the likelihood of 

harmful change occurring in the natural populations of aquatic flora and fauna of Florida 

streams at TN and TP concentrations above the proposed numeric nutrient criteria in 

today’s proposal. EPA conducted this review to confirm whether its proposed numeric 

nutrient criteria are established at TN and TP concentrations sufficient (i.e., necessary) to 

protect against “harmful” change in the biota.

EPA’s review confirmed its original decision that the criteria the Agency 

published in December 2010 were set at the appropriate levels to protect the applicable 

designated uses and translate Florida’s narrative nutrient criterion for the purposes of the 

CWA. EPA has re-selected the upper percentile of annual average TN and TP 

 31 As set out more fully in a subsequent section, EPA set criteria concentrations at the 90th percentile of the 

reference condition distribution in four of the five nutrient watershed regions defined in Florida. In the fifth 

region, known as the West Central region, EPA set criteria concentrations at the 75th percentile of the 

reference distribution. For ease of reference, where EPA refers to the “upper percentile” or the “90th

percentile” in this preamble, unless the reference relates specifically to the basis for the criteria in the four 

nutrient watershed regions where EPA selected the 90th percentile, EPA is referring to both the 90th

percentile that was applied in four regions and the 75th percentile that was applied in the West Central 

region.
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concentrations from its sample of reference sites as the level that the Agency is confident 

will avoid “harmful” increases in TN and TP, and thus a level at which designated uses 

are protected in Florida's streams. The reference sites (described more fully in the 

following sections) are least-disturbed and more closely represent minimally-impacted 

conditions associated with a natural population of flora and fauna. By selecting a 

criterion-magnitude that was exceeded only 10% of the time32 on an annual average basis 

in the reference sites that were determined to support designated uses, EPA is confident

that other streams attaining and maintaining those levels of TN and TP would also 

support applicable designated uses and not experience harmful change in the biota. EPA

is, therefore, proposing TN and TP criteria at the same levels as EPA promulgated in the

December 2010 final rule. 

In its decision, the court, in discussing numeric criteria translating Florida’s 

narrative criterion, stated that “the right target was a criterion that would identify a 

harmful increase in a nutrient level – an increase that, in the language of Florida’s 

narrative criterion, would create an ‘imbalance’ in flora and fauna.” Order at 63. That 

language could be read as requiring identification of the exact point where harmful 

change, or imbalance of flora or fauna, occurs as the appropriate level for numeric 

nutrient criteria. EPA evaluated whether available data allow derivation of criteria with 

such precision to set the criteria at a level where any increase at all would result in an 

imbalance of flora and fauna, and therefore impairment of Florida’s designated uses. As 

set out more fully in subsequent sections, EPA concluded the data did not allow 

derivation of criteria with such precision. In order to derive criteria with such precision, it 

 32 In the West Central Region, EPA selected a criterion-magnitude that was exceeded only 25% of the time 

on an annual average basis across all sites.

Comment [MS22]: See comment MS4

Comment [MS23]: See comment MS4
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would be necessary to have sufficient data to precisely model (either statistically or 

mechanistically) the stressor- response relationship in each stream reach within the State,

due to the various confounding factors that introduce variability into that relationship 

within a given stream reach. Because EPA did not have such data available, EPA was not 

able to pinpoint the exact level at which any increase in nitrogen and phosphorus 

concentrations at all would result in such imbalance and designated use impairment.

In determining appropriately protective criteria, EPA must ensure that such 

criteria comply with the CWA. The CWA envisions that water quality standards will be 

developed, based on available scientific knowledge and information, at levels that are

sufficient to protect designated uses. See CWA section 303(c)(2)(A). 40 CFR 

§131.11(a)(1). The record supports EPA’s conclusion that its proposed numeric streams

criteria are based on sound scientific rationale and will protect Florida’s designated uses.

If commenters are aware of available data and/or information demonstrating that setting 

criteria at less stringent levels than those in this proposed rule would be protective of 

designated uses and protect against harmful increases of TN and TP, or that criteria must 

be set at more stringent levels in order to protect designated uses and protect against 

harmful increases of TN and TP, commenters should submit such scientific information 

and analyses to EPA during the comment period for EPA’s consideration. 

Finally, EPA’s approach to deriving numeric nutrient criteria is consistent with 

FDEP’s approach to interpreting its narrative nutrient criterion and deriving numeric 

thresholds at the State level. FDEP recently established numeric interpretations of the 

State’s narrative nutrient criterion.33 FDEP has approached the derivation of numeric TN 

 33 See FDEP’s Rule 62-302.531, F.A.C. at:

Comment [MS24]: See comment MS4
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and TP threshold values for streams in much the same way as EPA by aiming to prevent 

adverse effects to natural populations of aquatic flora and fauna.

34 To set protective 

numeric threshold values for streams for TN and TP where the data were not available to 

ascertain an accurate quantifiable stressor-response relationship for streams, FDEP 

utilized a reference condition approach similar to the reference condition approach that 

EPA utilized in the December 2010 final rule. In the absence of a positive showing that 

some higher level of nutrients still protects designated uses and against harmful change in 

the biota in a particular stream, or a showing that some lower level of nutrients is needed 

to protect designated uses and natural populations of biota in a particular stream, both 

FDEP and EPA have determined that the upper percentile of reference streams is an

appropriate and protective level of nutrients to properly protect designated uses and avoid 

any adverse change in natural populations of aquatic flora or fauna. In addition, EPA 

included a Site Specific Alternative Criteria (“SSAC”) provision in its December 2010

final rule for adoption of alternative criteria if a demonstration could be made that more 

or less stringent criteria are warranted for individual waters. Similarly, FDEP included a 

provision in its rule for adoption of SSAC, as well as a provision for adoption of other 

site-specific interpretations for individual waters.

Along with this proposed rule, EPA is providing a technical support document that 

discusses in more detail the scientific basis for the proposed criteria for streams and the 

 

http://www.dep.state.fl.us/water/wqssp/nutrients/docs/meetings/62_302_final.pdf, accessed on April 27, 

2012.

34 State of Florida Numeric Nutrient Criteria Development Plan, Prepared by: Bureau of Assessment and 

Restoration Support, Division of Environmental Assessment and Restoration, Florida Department of 

Environmental Protection Tallahassee, FL, March 2009; Technical Support Document: Development of 

Numeric Nutrient Criteria for Florida Lakes and Streams. Florida Department of Environmental 

Protection, Standards and Assessment Section, June 2009; Technical Support Document: Development of 

Numeric Nutrient Criteria for Florida Lakes, Spring Vents and Streams. Florida Department of 

Environmental Protection, Standards and Assessment Section, 2012.

Comment [MS25]: Information specific to the 

effect of nutrients in Florida streams is located in 

Section II.A. See also the discussion on harmful 

effects specific to Florida streams in Section III.C.3.

Also, the portions of this rule that were not 

remanded, allows for the development of sitespecific alternative criteria that can be established 

where conditions warrant and it is appropriate
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default options to determine DPVs for unimpaired lakes. The technical support document 

helps explain how EPA’s proposed numeric streams criteria would prevent harmful 

increases in TN and TP concentrations, which was specifically discussed by the Court in 

its decision invalidating EPA’s numeric streams criteria and default DPV for unimpaired 

lakes.35

B. EPA Derivation of Numeric Nutrient Criteria for Streams

1. Components of Water Quality Criteria

Water quality criteria include three components. The first component is 

“magnitude,” the concentration of a pollutant that can be maintained over time in the 

ambient receiving water without adversely affecting the designated use that the criteria is 

intended to support. The second component is “duration,” or the time period over which 

exposure is averaged (i.e., the averaging period) to limit the duration of exposure to 

elevated concentrations. This accounts for the variability in the quality of the ambient 

water due to variations of constituent inputs, stream flow, and other factors. The third 

component is “frequency,” or how often the magnitude/duration condition may be 

exceeded and still protect the designated use. Combining the criterion-magnitude with the 

duration and frequency prevents the allowance of harmful effects by ensuring 

compensating periods of time during which the concentration is below the criterionmagnitude. Where criterion-magnitudes are exceeded for short periods of time or 

infrequently, water bodies can typically recover; that is, designated uses are typically 

protected. Designated uses are typically not protected when criteria-magnitudes are 

 35 “Technical Support Document for EPA’s Proposed Rule for Numeric Nutrient Criteria to Protect 

Florida’s Streams and the Downstream Protection of Unimpaired Lakes” (“EPA Proposed Rule TSD for 

Florida’s Streams and DPV for Unimpaired Lakes”).
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exceeded for longer periods of time (i.e., for longer than the specified duration) or more 

frequently (i.e., more often than the allowed frequency). 36

Use of this magnitude-duration-frequency format allows for some exceedances of 

the criteria-magnitude concentrations while still protecting applicable designated uses, 

which is important for pollutants such as nitrogen and phosphorus because their

concentrations can vary naturally in the environment. The duration and frequency values 

associated with the numeric streams criteria EPA is proposing today are the same as those 

associated with the numeric criteria in EPA’s December 2010 rule. For more information 

on the basis for these duration and frequency components, see 75 Fed. Reg. 75776-77.

2. Selection of Target for Numeric Nutrient Criteria

In evaluating the appropriate endpoint for deriving numeric nutrient criteria, EPA 

first looked at Florida’s applicable designated uses since, as mentioned in the previous 

sections, water quality criteria must be sufficient to protect the designated uses. CWA 

303(c)(2)(A); 40 CFR § 131.11(a)(1). The designated uses established by Florida for its 

streams include Class I (for potable water supply) and Class III (recreation, propagation 

and maintenance of a healthy, well-balanced population of fish and wildlife). Fla. Admin. 

Code 62-302.400. EPA next looked to Florida’s narrative nutrient criterion, which 

represents Florida’s determination of what is protective of the Class I and III designated 

uses.37 That criterion provides that “in no case shall nutrient concentrations of a body of 

 36 Water Quality Standards Handbook: Second Edition, Chapter 3 – Water Quality Criteria. EPA-823-B-94-

005a. USEPA. 1994; Technical Support Document for Water Quality-based Toxics Control. Appendix D –

Duration and Frequency. EPA/505/2-90-001. USEPA 1991. 37 Florida’s narrative nutrient criterion also serves to protect their Class II waters for propagation and 

harvesting of shellfish, which will be covered under EPA’s forthcoming rulemaking efforts for estuarine 

and coastal waters.
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water be altered so as to cause an imbalance of natural populations of aquatic flora and 

fauna”. Fla. Admin. Code 62-302.530(47)(b). As set out more fully in subsequent 

sections, in deriving the numeric nutrient criteria to protect against concentrations of TN

and TP that will create an imbalance of natural populations of aquatic flora and fauna 

and, thus, ensure the protection of the designated uses in Florida’s streams, EPA used the 

reference condition approach. 

Unlike for streams, for Florida’s lakes the Agency was able to accurately quantify 

a stressor-response relationship between TN and TP concentrations and harmful, adverse 

effects in those waters. EPA used that stressor-response information to derive numeric 

nutrient criteria, promulgated in the December 2010 final rule, to protect designated uses 

for Florida’s lakes. EPA did not establish the numeric lake criteria exactly at the point 

where nutrient pollution is demonstrated to adversely affect all lakes at all times, as that 

would not be protective of all lakes. Rather, EPA established the numeric lake criteria at 

concentrations that were known to protect against harmful, adverse effects by protecting 

and maintaining the expected trophic state38 (by meeting protective chlorophyll-a

concentrations for either oligotrophic or mesotrophic conditions) for the majority of 

lakes. At the same time, EPA allows higher concentrations within a given range if there is 

a positive showing that some higher concentrations of TN and TP still maintain the 

protective chlorophyll-a concentrations, and thus still protect the designated uses in a 

particular lake.

39 The court upheld EPA’s numeric nutrient criteria for Florida’s lakes in 

its February 18, 2012 Order. 

 38 Tropic state describes the nitrogen and phosphorus levels and algal state of an aquatic system: 

oligotrophic (low nitrogen/phosphorus and algal productivity), mesotrophic (moderate nitrogen/phosphorus 

and algal productivity), and eutrophic (high nitrogen/phosphorus and algal productivity). 39 Additionally, the SSAC provision at §131.43(e) is also available if it determined that concentrations 

Comment [MS26]: See comment MS4.
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For Florida’s streams, as stated in the previous section, EPA determined that the 

scientific data and information available were insufficient to establish accurate 

quantifiable relationships between TN and TP concentrations and harmful, adverse 

effects in streams due to confounding factors that affect the chemical and biological 

responses to nutrient pollution in streams, such as shading from canopy and stream 

velocity. Thus, in spite of the substantial data collected over many years, EPA could not 

use the stressor-response approach to establish the numeric streams criteria at 

concentrations that protect against harmful adverse effects by protecting and maintaining 

a given biological response at a protective level measured in streams. Therefore, EPA 

relied upon the reference condition approach as described in more detail in Section III.C 

of this preamble to identify TN and TP concentrations that protect the designated uses, 

and above which harmful, adverse effects are likely to occur in the majority of Florida 

streams. At the same time, EPA allows alternative criteria be set at higher or lower 

concentrations through the use of the SSAC provision, if there is a positive showing that 

higher or lower concentrations of TN and TP are sufficient or necessary to protect the 

designated uses in a particular stream. The following sections set forth how EPA 

determined that the numeric streams criteria in today’s proposal are set at the appropriate 

level to protect against a harmful, adverse effects due to increased TN and TP

concentrations.

C. Reference Condition Approach for Developing Numeric Nutrient Criteria for Streams

 

outside of the range are necessary to protect the designated uses in a particular lake.

Comment [MS27]: See comment MS4
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The reference condition approach, a long-standing peer-reviewed methodology 

published by EPA, was designed to develop protective numeric nutrient criteria where 

reference conditions can be confidently defined. 40 The reference condition approach, 

which has been well documented, peer reviewed, and developed in a number of different 

contexts,

41,42,43,44,45,46 is used to derive numeric nutrient criteria that are protective of 

applicable designated uses by identifying TN and TP concentrations occurring in leastdisturbed, healthy streams that are supporting designated uses. The core scientific basis 

for EPA’s use of the reference condition approach to derive the proposed numeric

nutrient criteria for Florida’s streams is outlined in EPA’s December 2010 final rule47

and final December 2010 rule TSD.48 Briefly, EPA screened and evaluated water 

chemistry data from more than 11,000 samples from over 6,000 sites Statewide. EPA also 

evaluated biological data consisting of more than 2,000 samples from over 1,100 Florida 

streams. EPA then selected a reference set of streams where the Agency was confident 

 40 USEPA. 2000. Nutrient Criteria Technical Guidance Manual: Rivers and Streams. EPA–822–B–00–002. 

U.S. Environmental Protection Agency, Office of Water, Washington, DC.; USEPA-SAB. 2011. Review of 

EPA’s draft Approaches for Deriving Numeric Nutrient Criteria for Florida’s Estuaries, Coastal Waters, 

and Southern Inland Flowing Waters. U.S. Environmental Protection Agency, Science Advisory Board, 

Washington, DC.

41 USEPA. 2000a. Nutrient Criteria Technical Guidance Manual: Lakes and Reservoirs. EPA-822-B-00-

001. U.S. Environmental Protection Agency, Office of Water, Washington, DC.

42 USEPA. 2000b. Nutrient Criteria Technical Guidance Manual: Rivers and Streams. EPA-822-B-00-002. 

U.S. Environmental Protection Agency, Office of Water, Washington, DC.

43 Stoddard, J. L., D. P. Larsen, C. P. Hawkins, R. K. Johnson, and R. H. Norris. 2006. Setting expectations 

for the ecological condition of streams: the concept of reference condition. Ecological Applications

16:1267 – 1276. 44 Herlihy, A. T., S. G. Paulsen, J. Van Sickle, J. L. Stoddard, C. P. Hawkins, L. L. Yuan. 2008. Striving for 

consistency in a national assessment: the challenges of applying a reference-condition approach at a 

continental scale. Journal of the North American Benthological Society 27:860 – 877. 45 U.S. EPA. 2001. Nutrient Criteria Technical Manual: Estuarine and Coastal Marine Waters. Office of 

Water, Washington, DC. EPA-822-B-01-003. 46 USEPA-SAB. 2011. Review of EPA’s draft Approaches for Deriving Numeric Nutrient Criteria for

Florida’s Estuaries, Coastal Waters, and Southern Inland Flowing Waters. U.S. Environmental Protection 

Agency, Science Advisory Board, Washington, DC.

47 Final rule can be found at: http://edocket.access.gpo.gov/2010/pdf/2010-29943.pdf or 75 Federal 

Register 75762 (December 6, 2010).

48 Final rule TSD can be found at: www.regulations.gov, Docket # EPA-HQ-OW-2009-0596.
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that designated uses are protected. Finally, EPA selected an upper percentile of the data 

distribution associated with those reference streams as the stream criterion-magnitude.

While developing the December 2010 final rule, EPA met and consulted with FDEP 

expert scientific and technical staff on numerous occasions as part of an ongoing 

collaborative process. EPA carefully considered and evaluated the technical approaches 

and scientific analysis that FDEP presented as part of its July 2009 draft numeric nutrient 

criteria,49 as well as FDEP’s numerous comments on different aspects of EPA’s proposed 

January 2010 final rule.

In addition, the Agency also received and carefully considered substantial 

stakeholder input from 13 public hearings in six Florida cities during the 2010 comment

period. EPA reviewed and evaluated further analysis and information included in the 

more than 22,000 comments on the January 2010 proposal and an additional 71 

comments on the August 2010 supplemental notice and request for comment. Finally, in 

reviewing its 2010 application of the reference condition approach for purposes of this 

proposal, EPA also considered FDEP’s current rule, along with the technical approaches 

and scientific analysis supporting that rule, submitted to EPA on June 13, 2012.

50

1. Selection of Reference Sites

 49 FDEP. 2009. Draft Technical Support Document: Development of Numeric Nutrient Criteria for 

Florida’s Lakes and Streams. Florida Department of Environmental Protection, Standards and Assessment 

Section. Available electronically at: 

http://www.dep.state.fl.us/water/wqssp/nutrients/docs/tsd_nutrient_crit.docx. Accessed October 2010. 50 State of Florida Numeric Nutrient Criteria Development Plan, Prepared by: Bureau of Assessment and 

Restoration Support, Division of Environmental Assessment and Restoration, Florida Department of 

Environmental Protection Tallahassee, FL, March 2009; Technical Support Document: Development of 

Numeric Nutrient Criteria for Florida Lakes, Spring Vents and Streams. Florida Department of 

Environmental Protection, Standards and Assessment Section, 2012.

Comment [MS28]: See comment MS4
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This section summarizes how EPA applied the reference condition approach in 

developing the December 2010 rule, including how EPA selected the set of reference 

sites and how it aggregated data associated with those stream segments. EPA classified 

Florida streams into five stream regions based on similar geographical and watershed 

characteristics. The proposed numeric streams criteria would apply to five separate 

stream Nutrient Watershed Regions (NWRs): Panhandle West, Panhandle East, North 

Central, West Central and Peninsula (north of Lake Okeechobee, including the 

Caloosahatchee River Watershed to the west and the St. Lucie Watershed to the east).

To derive numeric nutrient criteria for streams, EPA first identified biologically 

healthy sites that exhibited the least amount of human disturbance and that were known 

to support designated uses, i.e., support natural populations of aquatic flora and fauna.

EPA applied several screening factors to ensure these sites reflected least-disturbed, 

biologically healthy conditions. The screening factors included landscape development 

intensity index (LDI) scores less than 2.0 (an indicator of lower impact surrounding land 

use), average nitrate concentrations less than 0.35 mg/L (an indicator of lower 

anthropogenic nitrogen concentrations), exclusion of waters that are identified as water 

quality-limited for nutrients and/or dissolved oxygen on Florida’s EPA-approved CWA 

section 303(d) list, and an FDEP-derived index of the stream macroinvertebrate 

community (stream condition index, or SCI) where average scores are greater than 40 (an 

indicator of a healthy macroinvertebrate community). The result of this rigorous analysis 

was a set of reference sites that, although not pristine, reflected healthy conditions that 

were supporting designated uses, and thus free from harmful, adverse effects on natural 

populations of aquatic flora and fauna due to nutrient pollution. EPA has confidence that 
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these reference sites are supporting designated uses and natural populations of flora and 

fauna, and, as set out more fully in Section III.C.2, has confidence that if the TN and TP

concentrations are attained or maintained at the concentrations that are among the highest 

observed at these sites, then designated uses and natural populations of aquatic flora and 

fauna will be protected in other streams. Additionally, as discussed further in Section 

III.C.3, additional lines of evidence from the available scientific data and information

support EPA’s conclusion in that they indicate that harmful, adverse effects are likely to 

occur to natural populations of aquatic flora and fauna at levels higher than these 

concentrations.

In remanding EPA’s streams criteria, the Court preliminarily concluded that 

EPA’s technical and scientific approaches in deriving streams criteria based on the 

reference condition approach were defensible. Specifically, the Court reasoned: “Each 

side criticizes the Administrator’s implementation of this approach. Thus, for example, 

each side criticizes the Administrator’s selection of sample streams. The environmental 

parties criticize the duration and frequency components. These are matters of scientific 

judgment on which the rule would survive arbitrary-or-capricious review”. Order at 63. 

2. Selection of Stream Criterion-Magnitude

After selecting the reference set of streams, EPA then examined the statistical 

distributions of the data associated with stream sites that passed all of the screening 

factors in order to identify an appropriate criterion-magnitude to protect designated uses

and natural populations of aquatic flora and fauna. EPA organized the data (TN and TP 

values) and calculated the geometric mean of the annual geometric mean of TN and TP
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concentrations for each stream segment that contained reference sites. EPA used all 

samples from reference sites within a given stream segment in a given year to calculate 

the annual geometric mean for that stream segment. EPA used the geometric mean of 

these annual geometric means for each stream segment so that each stream segment 

represents one average concentration in the distribution of concentrations for each NWR. 

EPA used geometric means for all averages because concentrations were log-normally 

distributed. EPA then identified specific statistics, or percentiles, associated with each 

stream NWR reference condition data distribution as the stream criterion-magnitude for 

that region.51 Based on the effectiveness of the data quality screens in four of five NWRs, 

EPA has concluded that the 90th percentile of annual average concentrations would be 

protective. EPA could not use all of the screening factors outlined in Section III.C.1. in 

the previous section in order to identify reference sites in the remaining region, the West 

Central Region, because the use of those screens resulted in the identification of only one 

stream segment as a reference site. For this reason, EPA utilized only the SCI and 303(d) 

listed screens to identify reference conditions in the West Central NWR, and this 

approach does not rely on a quantitative assessment of potential human disturbance 

through the use of surrounding land cover analysis of stream corridor and watershed land 

development indices. Because of the use of fewer data screens to identify reference 

conditions in that NWR and EPA’s attendant lower confidence that these sites are leastdisturbed conditions that support designated uses and natural populations of aquatic flora 

 51 For the West Central region, where reference sites were identified using only the SCI approach, there is 

less confidence that these sites are least-disturbed and represent minimally-impacted conditions. Unlike in 

the other NWRs, this approach does not rely on a quantitative assessment of potential human disturbance 

through the use of surrounding land cover analysis of stream corridor and watershed land development 

indices, among other things. Therefore, because of the lower confidence level, EPA is proposing the 

streams criteria in the West Central region using a more conservative percentile of 75% rather than the 

upper end percentile of 90% of the distribution from the SCI sites.
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and fauna, EPA has determined the 75th percentile of annual average concentrations, 

rather than the 90th percentile, is the protective criterion-magnitude for that region. For 

the remaining stream regions, EPA considers the 90th percentile of the annual average 

concentrations observed in the reference condition distribution as an appropriate 

concentration to specify the criterion-magnitude because the Agency is confident that 

theses least-disturbed sites more closely represent minimally-impacted, biologically 

healthy reference conditions, which support the State’s Class I and III designated uses.

However, the Court found that EPA did not provide sufficient rationale explaining 

why it chose the 90th percentile (75th percentile in the West Central) of the reference site 

data distribution as the stream criterion-magnitude. That is, EPA did not explain why

increasing nutrient levels above the upper percentile of annual average concentrations 

measured in reference condition streams would result in harmful, adverse effects on 

natural populations of aquatic flora and fauna in Florida’s streams. The Court reasoned:

“The Administrator apparently concluded only that an increase above this level ordinarily 

causes a change in flora and fauna—not that it causes a harmful change. If there is a basis 

in sound science for disapproving a nutrient increase that causes any increase in flora and 

fauna, not just a harmful increase, the Administrator did not cite it. And even if the 

Administrator’s conclusion was that an increase in nutrients to a level above the 90th

percentile ordinarily causes a harmful change in flora and fauna, the Administrator again 

did not cite a sound science basis for the conclusion.” Order at 7.

For all stream regions, EPA could have selected a criterion-magnitude at the 75th

percentile of the frequency distribution of concentrations at reference sites, or any lower 

percentile of the frequency distribution of the general population of a stream class (i.e., 
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“all-streams” population from impaired to least-impacted), to derive the numeric criteria 

as recommended by EPA’s published streams criteria guidance.52 EPA selected the 90th

percentile. EPA found support in an EPA nutrient criteria guidance manual that 

recommends percentiles from the 75th to the 95th percentile of the frequency distribution 

of the reference population, where the higher percentile values are “best used to define 

the criteria when there is great confidence that the group of reference waters truly reflects 

reference conditions as opposed, for example, to best available condition.”53

The selection of the 90th percentile reflects EPA’s level of confidence that these 

least-disturbed sites more closely represent minimally-impacted conditions, while not set 

at the extreme upper end of the distribution (95th or 100th percentile). This is because 

these highest observed annual average concentrations (i.e., 95th or 100th percentile) have 

rarely been observed at any reference site and are most likely to be heavily influenced by 

extreme event factors (e.g., hurricanes, droughts). Thus these highest observed 

concentrations could be outliers that are not representative of conditions that would 

typically support designated uses and natural populations of aquatic flora and fauna.

Therefore, EPA has less confidence that such highest observed concentrations would

continue to be supportive of designated uses and natural populations of aquatic flora and 

fauna if maintained in all streams at all times.

Alternatively, the selection of a much lower percentile, such as a representation of 

the central tendency of the distribution (i.e., 50th percentile), would not be appropriate 

because it would imply that half of the conditions observed at reference sites would not 

 52 US EPA. 2000b. Nutrient Criteria Technical Guidance Manual: Rivers and Streams. EPA-822-B-00-002. 

U.S. Environmental Protection Agency, Office of Water, Washington, DC.

53 US EPA. 2007. Nutrient Criteria Technical Guidance Manual: Wetlands. EPA-822-R-07-004. U.S. 

Environmental Protection Agency, Office of Water, Washington, DC.
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support designated uses and natural populations of aquatic flora and fauna, when EPA’s 

analysis indicates that they do. For the West Central Region, EPA relied on the75th 

percentile due to the Agency’s lower level of confidence as discussed in more detail in 

the previous section. By setting the criteria at these concentrations, EPA believes the 

designated uses, i.e., natural populations of aquatic flora and fauna, will be protected 

when these concentrations are attained in the majority of the streams in the regions. For 

those streams that are shown to accommodate or require higher or lower concentrations, 

the SSAC provision is provided in EPA’s rule as discussed in Section III.C.5.

EPA has concluded, after its reevaluation of the reference condition data set and 

the resulting reference site data distributions of annual average TN and TP concentrations 

that EPA continues to have confidence that the upper percentile of annual average 

nutrient concentrations observed in the reference sites will support designated uses and 

natural populations of aquatic flora and fauna. As explained in the prior section, based on 

its evaluation of available scientific data and information, EPA used its best professional 

judgment and published guidance to conclude that TN and TP concentrations in excess of 

these values are not likely to protect designated uses and natural populations of aquatic 

flora and fauna. Additionally, as discussed in a subsequent section, EPA’s review of 

additional lines of evidence from the available scientific data and information, including 

past scientific analyses, new analyses, and the peer-reviewed scientific literature, all 

support the conclusion that harmful, adverse effects on natural populations of aquatic 

flora and fauna from excess nitrogen and phosphorus are more likely to occur if 

concentrations increase above the proposed streams criteria set at these upper percentiles 

of reference conditions.
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3. Harmful, Adverse Effects Due to Exceedence of EPA’s Proposed Streams

Criteria 

Additional lines of evidence from empirical stressor-response analyses and the 

peer-reviewed scientific literature, which indicate that harmful, adverse effects are likely 

to occur to natural populations of aquatic flora and fauna due to exceedances of the 

proposed streams criteria,54 support EPA’s conclusion that the upper percentile of the 

reference condition data distribution is the appropriate nutrient criterion-magnitude for 

Florida’s streams.

In developing this proposal, EPA reviewed the empirical, stressor-response 

analyses between nutrients and different biological response indicators (e.g., algal 

biomass, SCI) conducted prior to promulgation of the December 2010 final rule, and also 

reviewed any new analyses. The results of these analyses support the Agency’s 

conclusion that harmful, adverse effects to natural populations of aquatic flora and fauna 

are likely to occur if TN and TP concentrations increase above the proposed streams

criteria.55

Three technical support documents56 in the Agency’s original rulemaking record 

and the technical support document associated with this proposed rule include scientific 

 54 USEPA. 2000. Nutrient Criteria Technical Guidance Manual: Rivers and Streams. EPA–822–B–00–002. 

U.S. Environmental Protection Agency, Office of Water, Washington, DC.

55 Technical Support Document for EPA’s Proposed Rule for Numeric Nutrient Criteria to Protect 

Florida’s Streams and Downstream Lakes. USEPA, 2012. 56 Technical Support Document: Development of Numeric Nutrient Criteria for Florida Lakes and Streams. 

Florida Department of Environmental Protection, Standards and Assessment Section, June 2009; Proposed 

Methods and Approaches for Developing Numeric Nutrient Criteria for Florida’s Inland Waters. U.S. EPA 

2009; Technical Support Document for U.S. EPA’s Proposed Rule for Numeric Nutrient Criteria for 

Florida’s Inland Surface Fresh Waters. U.S. EPA 2010.
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analyses demonstrating that harmful changes or adverse effects are more likely to happen 

as TN and TP concentrations increase above EPA’s proposed streams criteria.

The effects of TN and TP on an aquatic ecosystem are well understood and 

documented. There is a substantial and compelling scientific basis for the conclusion that 

excess TN and TP will have adverse effects on streams.57,58,59,60,61,62,63,64,65,66,67,68,69,70,71

As discussed in Section II in the earlier section, excess nitrogen and phosphorus in 

streams, like other aquatic ecosystems, increase vegetative growth (plants and algae), and 

change the assemblage of plant and algal species present in the system. Notwithstanding 

the difficulty associated with identifying the TN and TP concentrations that are known to 

 57 Biggs, B.J.F. 2000. Eutrophication of streams and rivers: dissolved nutrient–chlorophyll relationships for 

benthic algae. Journal of the North American Benthological Society 19:17–31 58 Bothwell, M.L. 1985. Phosphorus limitation of lotic periphyton growth rates: an intersite comparison 

using continuous-flow troughs (Thompson River system, British Columbia). Limnology and Oceanography

30:527–542 59Bourassa, N., and A. Cattaneo. 1998. Control of periphyton biomass in Laurentian streams (Quebec). 

Journal of the North American Benthological Society 17:420–429 60 Bowling, L.C., and P.D. Baker. 1996. Major cyanobacterial bloom in the Barwon-Darling River, 

Australia, in 1991, and underlying limnological conditions. Marine and Freshwater Research 47: 643–657 61 Cross, W. F., J. B. Wallace, A. D. Rosemond, and S. L. Eggert. 2006. Whole-system nutrient enrichment 

increases secondary production in a detritus-based ecosystem. Ecology 87: 1556–1565 62 Dodds, W.K., and D.A. Gudder. 1992. The ecology of Cladophora. Journal of Phycology 28:415–427 63 Elwood, J.W., J.D. Newbold, A.F. Trimble, and R.W. Stark. 1981. The limiting role of phosphorus in a 

woodland stream ecosystem: effects of P enrichment on leaf decomposition and primary producers. 

Ecology 62:146–158 64 Francoeur, S.N. 2001. Meta-analysis of lotic nutrient amendment experiments: detecting and quantifying 

subtle responses. Journal of the North American Benthological Society 20: 358–368 65 Moss, B., I. Hooker, H. Balls, and K. Manson. 1989. Phytoplankton distribution in a temperate 

floodplain lake and river system. I. Hydrology, nutrient sources and phytoplankton biomass. Journal of 

Plankton Research 11: 813–835 66 Mulholland, P.J. and J.R. Webster. 2010. Nutrient dynamics in streams and the role of J-NABS. Journal 

of the North American Benthological Society 29: 100-117 67 Peterson, B.J., J.E. Hobbie, A.E. Hershey, M.A. Lock, T.E. Ford, J.R. Vestal, V.L. McKinley, M.A.J. 

Hullar, M.C. Miller, R.M. Ventullo, and G. S. Volk. 1985. Transformation of a tundra river from 

heterotrophy to autotrophy by addition of phosphorus. Science 229:1383–1386 68 Rosemond, A. D., P. J. Mulholland, and J. W. Elwood. 1993. Top-down and bottom-up control of stream 

periphyton: Effects of nutrients and herbivores. Ecology 74: 1264–1280 69 Rosemond, A. D., C. M. Pringle, A. Ramirez, and M.J. Paul. 2001. A test of top-down and bottom-up 

control in a detritus-based food web. Ecology 82: 2279–2293 70 Rosemond, A. D., C. M. Pringle, A. Ramirez, M.J. Paul, and J. L. Meyer. 2002. Landscape variation in 

phosphorus concentration and effects on detritus-based tropical streams. Limnology and Oceanography 47: 

278–289 71 Slavik, K., B. J. Peterson, L. A. Deegan, W. B. Bowden, A. E. Hershey, J. E. Hobbie. 2004. Long-term 

responses of the Kuparuk River ecosystem to phosphorus fertilization. Ecology 85: 939 – 954
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protect against harmful effects by protecting and maintaining a given biological response 

at a protective level measured in Florida’s streams, the available science clearly indicates 

that adverse responses to nutrient pollution occur.

For example, excess nitrogen and phosphorus promote the increased growth of 

opportunistic and short-lived plant species that die quickly, leaving more dead vegetative 

material available for consumption by lower tropic levels. Excess nitrogen and 

phosphorus can promote the increased growth of less palatable nuisance algae species 

that result in less food available for filter feeders. These negative changes can alter the 

habitat structure by covering the stream or river bed with periphyton (attached algae), 

and/or clogging the water column with phytoplankton (floating algae), both of which can 

adversely affect natural or desirable aquatic life. Excess nitrogen and phosphorus can also 

lead to the increased growth of algae that produce toxins that can be toxic to fish, 

invertebrates, and humans. Chemical characteristics of the water, such as pH and 

concentrations of dissolved oxygen (DO), can be affected by excess nitrogen and 

phosphorus, leading to low DO conditions and hypoxia that cannot support aquatic life.

All of these adverse effects change the balance of the natural populations of aquatic flora 

and fauna expected to occur. In turn, each of these negative changes can lead to other 

negative changes in the stream community and ecology and, ultimately, to harmful, 

adverse effects to the overall function of the linked aquatic ecosystem and subsequent 

failure to support designated uses. 

In light of this well-established paradigm, EPA reviewed the latest peer-reviewed 

scientific literature and found many nutrient thresholds where harmful, adverse effects in 

streams are coincident with or occur above EPA’s proposed streams criteria. In these 
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examples, there are regional and site-specific factors (e.g., precipitation, temperature, 

flow) that may account for the differences in the nutrient threshold concentrations, but, in 

general, EPA’s proposed streams criteria are consistent with the range of thresholds of 

harmful, adverse effects documented in the peer-reviewed scientific literature. For 

example, TN and TP concentrations ranging between 0.659-0.714 mg/L and 0.048-0.071 

mg/L, respectively, have been associated with moderate levels of productivity, or 

mesotrophy, in rivers and streams.72 Higher concentrations of nutrients lead to eutrophy, 

which is what numeric nutrient criteria, in general, are intended to prevent. As another 

example, increases in suspended chlorophyll-a, decreases in water clarity, and decreases 

in macroinvertebrate and fish abundance in Wisconsin rivers and streams were observed 

over a TN and TP range of 0.5-2.0 mg/L and 0.035-0.150 mg/L, respectively.73 Adverse 

increases in productivity (i.e., organic matter supply), also known as eutrophication, can 

negatively alter the metabolism of aquatic systems and lead to adverse environmental 

conditions such as depressed dissolved oxygen concentrations that cannot support aquatic 

life. These conditions, in turn, can harm macroinvertebrate and fish communities, 

creating changes to the balance of the natural populations of these aquatic fauna. The TN 

and TP concentrations above which these adverse effects are more likely to occur are 

coincident with EPA’s proposed streams criteria TN and TP concentrations.

Many of the thresholds reported in the latest peer-reviewed scientific literature 

vary in comparison to the proposed criteria for Florida’s streams due to site- and 

 72 Dodds, W.K. 2006. Eutrophication and trophic state in rivers and streams. Limnol. Oceanogr. 51(1):671-

680. 73 Robertson, D.M., B.M. Weigel, and D.J. Graczyk. 2008. Nutrient concentrations and their relations to the 

biotic integrity of nonwadeable rivers in Wisconsin. US Geological Survey and US Department of the 

Interior professional paper 1754; Robertson, D.M., D.J. Graczyk, P.J. Garrison, L. Wang, G. LaLiberte, and 

R. Bannerman. 2006. Nutrient concentrations ant their relations to the biotic integrity of wadeable streams 

in Wisconsin. US Geological Survey and US Department of the Interior professional paper 1722.
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regional-specific factors such as climate and stream flow. However, the nutrient 

concentrations reported in the literature demonstrate and confirm that harmful, adverse 

effects occur as TN and TP concentrations increase in streams and are likely to occur as 

concentrations increase above the criteria concentrations that EPA has selected for 

Florida streams. EPA considers the association of the TN and TP concentrations with 

documented harmful, adverse effects to be compelling and supportive of this proposed 

rule. For a complete list of comparable nutrient thresholds reported in the scientific 

literature, see “EPA Proposed Rule TSD for Florida’s Streams and DPVs for Unimpaired 

Lakes” (Chapter 1, Scientific Literature).

4. Additional evidence of harmful effects in Florida streams above EPA’s 

proposed criteria

In addition to reviewing the peer-reviewed scientific literature mentioned in the 

prior section, EPA reviewed analyses conducted by FDEP that demonstrated that excess 

nitrogen and phosphorus adversely affect streams. In its technical support document for 

deriving numeric nutrient criteria, FDEP stated: “The results of the analyses generally 

indicate that many of the biological measures evaluated exhibit a statistically significant 

adverse response to nutrient pollution; however, the relationships between the biological 

response variables and nutrient levels were confounded by numerous other factors such 

as color, pH, conductivity, and canopy cover. While DEP believes the effect of nutrients 

on the biological communities is not clear enough to be used as the sole basis for 

establishing numeric nutrient criteria, the observed relationships between nutrients and 

the various biological measures demonstrate the need for nutrient criteria to prevent 
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adverse biological effects in Florida streams. While the analysis in this chapter did not 

produce numeric thresholds that could be used as water quality criteria, the relationships 

that were determined, while relatively weak, do support the values derived using the 

Nutrient Benchmark Approach. Both the analysis of the Rapid Periphyton Survey 

(regarding probability of increased algal thickness) and the analysis of the second change 

point in the stream periphyton response to nutrients indicate that the biological response 

to nutrient enrichment will generally occur at levels higher than the values generated 

using the Benchmark Distribution Approach”.74

EPA has reviewed the available periphyton data in Florida streams and has 

verified that a harmful, adverse increase in the amount of algal coverage (> 6 mm thick 

over more than 25% of the stream bottom) will be substantially more likely as 

concentrations of TN and TP increase above EPA’s proposed numeric streams criteria. 

This adverse biological response represents harmful, adverse changes to the natural 

populations of aquatic flora that occur as concentrations increase above the protective 

values in EPA’s proposed numeric streams criteria. For more information on the 

likelihood of increases in the amount of algal coverage at varying concentrations of TN 

and TP, see “EPA Proposed Rule TSD for Florida’s Streams and DPVs for Unimpaired 

Lakes” (Chapter 1, Stressor-Response Relationships).

EPA also reviewed the available stream fauna data, specifically FDEP’s multimetric index of stream macroinvertebrates (e.g., insect larvae, worms), which FDEP 

developed as an indicator of stream health.75 The index, called the stream condition index 

 74 Technical Support Document: Development of Numeric Nutrient Criteria for Florida Lakes, Spring 

Vents and Streams. Florida Department of Environmental Protection, Standards and Assessment Section, 

2012, p. 110-111. 75 Technical Support Document for EPA’s Proposed Rule for Numeric Nutrient Criteria to Protect 
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(SCI), is a generic index, indicating the aggregate impact of human disturbance on stream 

macroinvertebrates. It measures the number and diversity of various invertebrate taxa 

(i.e., individuals sharing the same general identity) and was not designed to be uniquely 

responsive to nutrients, but nutrients may contribute to adverse impacts. The SCI score 

for a given sample can range between 0 and 100, where 0 represents a highly degraded 

community and 100 represents the highest quality community. EPA re-analyzed Floridaspecific stream data and found that stream macroinvertebrate community index scores 

predictably decrease below a level EPA and FDEP consider biologically healthy as a 

function of increasing TN and TP concentrations.

Furthermore, when ambient TN or TP concentrations were greater than EPA’s 

proposed criteria, SCI scores indicated that, on average, faunal populations were 

imbalanced. For example, SCI scores ranged from 30 to 50 when ambient TP 

concentrations were equivalent to EPA’s proposed TP criteria for each of the five stream 

NWRs. A SCI score of 50 has been identified by scientific experts to be associated with 

the loss of rare native taxa and with the replacement of some sensitive or ubiquitous taxa

by more pollutant tolerant taxa – this is a level where there is some negative change in 

the natural populations of aquatic fauna, but is still considered a score that represents a

biologically healthy condition; whereas a SCI score of 30 has been associated with 

unbalanced distribution of major groups from what is expected – this is a level where 

there is a profound harmful change in the natural populations of aquatic fauna.76

EPA applied the average SCI of 40 as one of many screening factors in selecting 

reference sites that were considered to be biologically healthy. EPA believes an average 

 

Florida’s Streams and Downstream Lakes. USEPA, 2012. 76 Technical Support Document for U.S. EPA’s Final Rule for Numeric Criteria for Nitrogen/Phosphorus 

Pollution in Florida’s Inland Surface Fresh Waters. U.S. EPA 2010, pp. 49-51.
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SCI of 40 is a level where there is some negative change in the natural populations of 

aquatic fauna, but before profound harmful change has occurred.77 Following the court’s 

remand of the streams criteria, EPA evaluated data in Florida streams and found that 

when the nutrient concentrations exceed EPA’s proposed numeric streams criteria, the 

SCI score is 45-70% more likely to be less than 50, meaning that it is more likely that 

there will be some negative change as TN and TP concentrations increase above EPA’s 

proposed streams criteria. In addition, when the nutrient concentrations exceed EPA’s 

proposed numeric streams criteria, the SCI score is 17-34% more likely to be less than 

30, meaning that it is more likely that there will be profound harmful change. Thus, the 

concentrations of EPA’s proposed numeric streams criteria represent levels above which 

harmful change begins to be more likely. This adverse biological response represents 

harmful, adverse changes to the natural populations of aquatic fauna that occur at 

concentrations above the protective values in EPA’s proposed numeric streams criteria. 

For more information on the likelihood of SCI scores at varying concentrations of TN 

and TP, see “EPA Proposed Rule TSD for Florida’s Streams and DPVs for Unimpaired 

Lakes” (Chapter 1, Stressor-Response Relationships).

When considered together and in light of the conclusions drawn by FDEP78, the 

previous and new analyses all indicate that a predictable harmful, adverse change (i.e., 

increase in TN and TP concentrations causing imbalance in natural populations of aquatic 

flora or fauna) would likely occur if levels of TN and TP exceed the proposed streams

criteria.

 77 Technical Support Document for U.S. EPA’s Final Rule for Numeric Criteria for Nitrogen/Phosphorus 

Pollution in Florida’s Inland Surface Fresh Waters. U.S. EPA 2010. 78 Technical Support Document: Development of Numeric Nutrient Criteria for Florida Lakes and Streams.

Florida Department of Environmental Protection, Standards and Assessment Section, June 2009, p. 96.
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5. EPA’s rule includes the SSAC provision and process to address any 

uncertainties associated with the reference condition approach

EPA recognizes the uncertainties associated with setting numeric nutrient criteria

based on the reference condition approach. The case law is clear, however, that in 

protecting human health and the environment, EPA can act in light of scientific 

uncertainty and choose to act proactively. American Iron & Steel Institute, 115 F.3d 979, 

(D.C. Cir. 1997)(“[I]t is within EPA’s discretion to decide that in the wake of uncertainty, 

it would be better to give the values a conservative bent rather than err on the other 

side.”). While it was appropriate for EPA to act to adopt numeric nutrient criteria for 

streams based on the reference condition approach even in the face of some scientific 

uncertainty, EPA also recognized that site-specific water quality conditions may make it

appropriate to adopt either more or less stringent numeric nutrient criteria for a specific 

water body or set of water bodies. To address those situations, and as discussed 

previously in this proposal, EPA’s December 2010 final rule authorized and established a 

specific administrative process for adopting, site-specific alternative criteria (“SSAC”).

D. Proposed Numeric Criteria for the State of Florida’s Streams

EPA is proposing numeric nutrient criteria for TN and TP in five geographically 

distinct watershed regions of Florida’s streams not covered by the State of Florida’s Rule 

classified as Class I or III waters under Florida law (Section 62-302.400, F.A.C.). The 

proposed TN and TP criteria are listed in Table B-1. The proposed criteria are the same 

criteria published in EPA’s final rule signed on November 14, 2010 and published at 75 
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FR 75762 (December 6, 2010). For purposes of this proposed rule and in response to the 

Court’s February 18, 2012 order, EPA is proposing these criteria values and explaining 

how the proposed criteria will ensure the protection of the Florida’s Class I and III 

designated uses by avoiding harmful changes in TN and TP concentrations that would 

result in an imbalance of natural populations of aquatic flora or fauna. EPA requests 

comment on its proposed numeric nutrient criteria for Florida’s streams and supporting 

rationale.

Table B-1. EPA’s Proposed Numeric Criteria for Florida Streams not covered by the 

State of Florida’s Rule.

Nutrient Watershed Region

Instream Protection Value Criteria

TN (mg/L) * TP (mg/L) *

Panhandle West a 0.67 0.06

Panhandle East b 1.03 0.18

North Central c 1.87 0.30

West Central d 1.65 0.49

Peninsula e 1.54 0.12

Watersheds pertaining to each Nutrient Watershed Region (NWR) were based principally on the NOAA 

coastal, estuarine, and fluvial drainage areas with modifications to the NOAA drainage areas in the West 

Central and Peninsula Regions that account for unique watershed geologies. For more detailed information 

on regionalization and which WBIDs pertain to each NWR, see the Technical Support Document. a Panhandle West region includes: Perdido Bay Watershed, Pensacola Bay Watershed, Choctawhatchee 

Bay Watershed, St. Andrew Bay Watershed, Apalachicola Bay Watershed.

b Panhandle East region includes: Apalachee Bay Watershed, and Econfina/Steinhatchee Coastal Drainage 

Area.

c North Central region includes the Suwannee River Watershed.

d

West Central region includes: Peace, Myakka, Hillsborough, Alafia, Manatee , Little Manatee River 

Watersheds, and small, direct Tampa Bay tributary watersheds south of the Hillsborough River Watershed. e Peninsula region includes: Waccasassa Coastal Drainage Area, Withlacoochee Coastal Drainage Area, 

Crystal/Pithlachascotee Coastal Drainage Area, small, direct Tampa Bay tributary watersheds west of the 

Hillsborough River Watershed, Sarasota Bay Watershed, small, direct Charlotte Harbor tributary 

watersheds south of the Peace River Watershed, Caloosahatchee River Watershed, Estero Bay Watershed, 

Kissimmee River/Lake Okeechobee Drainage Area, Loxahatchee/St. Lucie Watershed, Indian River 

Comment [MS29]: See comment MS4
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Watershed, Daytona/St. Augustine Coastal Drainage Area, St. John’s River Watershed, Nassau Coastal 

Drainage Area, and St. Mary’s River Watershed.

* For a given waterbody, the annual geometric mean of TN or TP concentrations shall not exceed the 

applicable criterion concentration more than once in a three-year period.

E. Proposed Numeric Criteria to Ensure the Downstream Protection of the State of 

Florida’s Unimpaired Lakes

Similar to the Court’s opinion regarding EPA’s streams criteria, the Court found 

that EPA had not explained in sufficient detail how exceedances of the default DPV for 

unimpaired lakes would lead to “harmful effects” in the downstream lake. Order at 70.

Thus, the Court invalidated the option for establishing default DPVs to protect 

unimpaired lakes in EPA’s final rule and remanded it to the Agency for further action.

Order at 85. This proposed rule provides three options for establishing a default DPV for 

unimpaired lakes and clarifies that the proposed options would ensure the attainment and 

maintenance of the numeric lake criteria so as to prevent harmful effects from occurring 

in a downstream lake.

EPA is proposing default DPV approaches for TN and TP that would provide for 

the attainment and maintenance of downstream water quality standards for Florida’s 

unimpaired lakes pursuant to 40 CFR §131.10(b) when modeling approaches are 

unavailable. For this proposed rule, EPA is providing for public comment three default 

approaches available for use when modeling cannot be performed to derive DPVs that 

ensure the attainment and maintenance of the numeric lake criteria that, in turn, protect

the designated uses in Florida’s lakes. The default approaches would be applicable to 

streams that flow into unimpaired lakes, but could also be used for streams that flow into 

impaired lakes. The default approaches would supplement EPA’s promulgated DPVs for 
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the protection of downstream lakes, which are codified at 40 CFR §131.43(c)(2)(ii), 

consistent with the February 18, 2012 Court order. Order at 85.

Briefly, EPA’s final rule provided that DPVs apply to tributary streams at the 

point of entry to the lake, also referred to as the pour point. The final rule specified that 

where sufficient data and information are available, DPVs may be established through 

application of the BATHTUB model. See 40 CFR §131.43(c)(2)(ii)(B). EPA’s final rule 

also specifically authorizes FDEP or EPA to use a model other than BATHTUB when 

either FDEP or EPA determines that it would be appropriate to use another scientifically 

defensible modeling approach that results in the protection of downstream lakes. 40 CFR 

§131.43(c)(2)(ii)(B). A lake-specific DPV derived through such modeling provides the 

most refined DPV for a stream at the pour point. Where sufficient information is not 

available to derive TN and/or TP DPVs using water quality modeling and the lake does 

not attain the applicable TN, TP, and/or chlorophyll-a criteria or is un-assessed, criteria 

values for TN and/or TP that apply to that lake are to be used as the default DPVs. 40 

CFR §131.43(c)(2)(ii)(D). See id. EPA believes that this approach, which the Court 

upheld, is protective because the TN and TP concentrations entering the lake are unlikely 

to need to be lower than the criterion concentration necessary to be protective of the lake 

itself.

In the final rule, water quality modeling was EPA’s preferred approach for the 

derivation of DPVs. Water quality modeling is the most rigorous and most datademanding method and results in the most refined DPVs. The default methods were 

intended only for use where there is insufficient data to use a model. While using a 

default option to develop DPVs requires less data, it also generally leads to more 
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stringent criteria to account for the uncertainties associated with these less refined 

approaches.

The rule proposed today provides three options for a default DPV that would 

apply in cases when there are insufficient data to use a water quality model for any 

unimpaired lake for which EPA has promulgated numeric nutrient criteria. The three 

default options EPA is proposing are not intended to supersede or limit the two

approaches EPA provided in the final rule, codified at 40 CFR §131.43(c)(2)(ii), which 

were upheld by the Court. Order at pp. 69-70, 85. Rather, the default options are intended 

to provide flexibility in deriving a DPV in the situation where there is not sufficient 

information to develop a DPV using a water quality model. Thus, EPA views the 

proposed DPV options as supplemental to EPA’s other established approaches for 

deriving DPVs. All three options for default DPVs are designed to ensure that the 

unimpaired lake criteria would be attained and maintained when the inflowing stream’s 

TN and TP concentrations meet the DPV at the pour point.

The first proposed default option simply utilizes the downstream lake criteria as 

the DPV applicable at the pour point to the lake. EPA refers readers to 40 CFR

§131.43(c)(1) for the applicable TN and TP lake criteria, which would serve as the DPV.

EPA believes that this proposed option is protective because it is unlikely that the TN and 

TP concentrations entering the lake need to be lower than the criterion concentration 

necessary to be protective of the lake itself.

The second proposed default option uses Florida-specific stream and lake data to 

empirically link the DPV to the attainment and maintenance of Florida’s lake criteria in 

each of the three lake classes. This option utilizes Florida’s extensive stream and lake 
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data to compute a linear regression model, which relates the inflowing stream TN and TP 

concentrations to the TN and TP concentrations in the downstream lake. EPA developed 

a linear regression model for each of the three lake classes based on EPA’s lake dataset 

provided in the final rule and Florida’s stream data from its statewide water quality 

database79.

The linear regression equation is used to predict what the inflowing stream's TN 

and TP concentrations need to be in order for the lake concentrations to meet the lake 

criteria EPA established in the December 6, 2010 final rule. EPA’s calculated TN and TP 

DPVs for each lake class using this approach are provided in Table C-1. The approach is 

described in further detail in the EPA Proposed Rule TSD for Florida’s Streams and 

DPVs for Unimpaired Lakes.

For this proposed option, in circumstances where additional lake and stream data 

are available, the linear regression equation could be updated using this new data and 

used to calculate default DPVs that are reflective of newer, more site-specific 

information.

Table C-1. EPA’s proposed DPVs for each lake class using the second default approach.

Default Option 2

Lake Class TN DPV (mg/L) TP DPV (mg/L)

Colored Lakes 1.59 0.11

Clear, High 

Alkaline Lakes 1.40 0.09

Clear, Low 

Alkaline Lakes 0.87 0.06

 79 IWR Run 40. 
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The third proposed default option utilizes stream data that is spatially linked to 

and temporally coincident with the downstream lake when it is attaining the applicable 

lake criteria. This proposed option is a reference condition-based DPV approach that is 

conditioned upon the downstream lake attaining all applicable numeric nutrient criteria, 

TN, TP, and chlorophyll-a, including the duration and frequency components of the 

applicable lake criteria. To compute a reference condition-based DPV, the period of 

record during which the downstream lake was attaining all applicable criteria must be 

determined. At a minimum, and pursuant to 40 CFR §131.43(c)(1), the lake must not 

exceed any applicable numeric nutrient criteria, which are expressed as annual geometric 

means, more than once in a three-year period. If this condition is met, then a DPV for that 

lake can be computed using TN and TP data from the stream discharging into the lake 

coincident in time with the period of record when the lake was attaining all applicable 

numeric nutrient criteria. Because of the hydrologic link between streams and lakes, it 

follows that nitrogen and phosphorus concentrations in the stream would be sufficient to 

meet the lake criteria provided that the lake was meeting all applicable numeric nutrient 

criteria. In general, this approach is less refined compared to the modeling approach EPA 

promulgated at 40 CFR §131.43(c)(1)(ii)(B) because it does not incorporate the water 

quality parameters and data that would be necessary to derive a site-specific DPV, for 

either TN or TP, using a water quality model such as BATHTUB. Nonetheless, EPA 

believes that the data and information that would support this third approach, in the 

absence of additional data that would support modeling, is still sufficient to ensure the 

protection of the downstream lake because of the hydrologic linkage between the stream 

and downstream lake. A DPV calculated under this option may be more stringent than a 
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DPV calculated using a water quality model. This default approach is intended to ensure 

that water quality standards are not only restored when found to be impaired, but are 

maintained when found to be attained, consistent with the Clean Water Act. Higher levels 

of TN and/or TP may be allowed in watersheds where it is demonstrated that such higher 

levels will fully protect the lake’s water quality standard. To the extent that it is 

determined that the default DPV for a given lake tributary is over protective, applying a 

water quality model as set out in EPA’s preferred approach will result in a more refined

definition of the DPV for that tributary.

As discussed earlier, the calculation of the DPV using the three default options 

requires that the lake criteria be explicitly considered. The applicable numeric lake 

criteria can be found at 40 CFR §131.43(c)(1). EPA recognizes that lake criteria may be 

modified pursuant to the modified lake criteria provision at 40 CFR §131.43(c)(1)(ii).

Where lake criteria are modified in accordance with this provision, the modified criteria 

would be the applicable criteria in any of the three default DPV approaches. The duration 

and frequency components of DPV magnitudes computed using the proposed default 

approaches would be an annual geometric mean not to be exceeded more than once over 

a three-year period. These components of the proposed approaches align with the 

duration and frequency of both the numeric lake criteria, codified at 40 CFR

§131.43(c)(1), and the streams criteria which are proposed to be codified at 40 CFR 

§131.43(c)(2).

As in the final rule, protection of downstream lakes using the options described in 

this proposed rule is accomplished through establishment of a DPV. The applicable 

criteria for streams that flow into downstream lakes include both the instream criteria for 
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TN and TP and the DPV, which is a concentration or loading value at the point of entry 

of a stream into a downstream lake that ensures the attainment and maintenance of the 

numeric lake criteria. EPA selected the point of entry into the lake as the location to 

measure water quality because the lake responds to the input from the pour point and all 

contributions from the stream network above this point in a watershed affect the water 

quality at the pour point. When a DPV is exceeded at the pour point, the waters that 

collectively comprise the network of streams in the watershed above that pour point are 

considered to not attain the DPV for purposes of CWA section 303(d). The State may 

identify these impaired waters as a group rather than individually.

Contributions of TN and/or TP from sources in stream tributaries upstream of the 

pour point are accountable to the DPV because the water quality in the stream tributaries 

must result in attainment of the DPV at the pour point into the lake. The spatial allocation 

of load within the watershed is an important accounting step to ensure that the DPV is 

achieved at the point of entry into the lake. How the watershed load is allocated may 

differ based on watershed characteristics and existing sources (e.g., areas that are more 

susceptible to physical loss of nitrogen; location of towns, farms, and dischargers), so 

long as the DPV is met at the point of entry into the downstream lake. Where additional 

information is available, watershed modeling could be used to develop allocations that 

reflect hydrologic variability and other water quality considerations. For protection of the 

downstream lake, what is important is an accounting for nutrient pollution loadings on a 

watershed scale that results in meeting the DPV at the point of entry into the downstream 

lake.
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As in the December 6, 2010 final rule, this proposal provides that additional 

DPVs may be established in upstream locations to represent sub-allocations of the total 

allowable loading or concentration. Such sub-allocations may be useful where there are 

differences in hydrological conditions and/or sources of TN and/or TP in different parts 

of the watershed. In addition to the explanations provided earlier, EPA refers the reader 

to its technical support document associated with the December 6, 2010 final rule for 

specific information supporting how harmful, adverse effects are more likely to occur in 

lakes at TN and TP concentrations above the established numeric lake criteria (Chapter 2, 

Derivation of EPA’s Numeric Nutrient Criteria for Lakes).

EPA requests comment on the three proposed default approaches, including 

whether implementation of DPVs calculated using the default approaches would ensure 

the attainment and maintenance of the downstream numeric lake criteria in Florida’s 

unimpaired lakes. The proposed default DPV approaches and DPVs are aimed at the 

protection of unimpaired lakes. However, EPA recognizes that the second and third 

options may also be appropriate for the protection of impaired lakes and offer additional 

flexibility to the default DPV approach for impaired lakes, which is codified at 40 CFR

§131.43(c)(2)(ii)(D). EPA requests comment on applying the second and third default 

DPV options to impaired lakes as well as unimpaired lakes. In addition, EPA requests 

comments on whether the Agency should promulgate default DPV values in addition to 

default DPV approaches to be used in situations when modeling is unavailable.

F. Applicability of Criteria When Final
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EPA proposes that the numeric nutrient criteria for Florida’s streams not covered 

by Florida’s Rule and the DPVs for unimpaired lakes described in this rule be effective 

for CWA purposes 60 days after EPA publishes final criteria, and apply in addition to any 

other criteria for Class I or Class III waters already adopted by the State and submitted to 

EPA (and for those adopted after May 30, 2000, approved by EPA). EPA requests 

comment on this proposed effective date.

In addition to this proposal, EPA has proposed to stay the December 6, 2010 Final 

Rule80 (75 FR 75762) to November 15, 2013 (See 

http://water.epa.gov/lawsregs/rulesregs/florida_inland.cfm) [add link for the stay 

proposal here]. This date should closely coincide with the effective date of this 

proposed rule, which is approximately 60 days following the publication of the final rule 

(i.e., shortly after August 31, 2013).

For water bodies that Florida has designated as Class I and III, any final EPA 

numeric nutrient criteria will be applicable CWA water quality criteria for purposes of 

implementing CWA programs including permitting under the NPDES program, as well 

as monitoring and assessment, and establishment of TMDLs. The proposed criteria in this 

rule, when finalized, would be subject to Florida’s general rules of applicability to the 

same extent as are other State-adopted and/or federally-promulgated criteria for Florida 

waters. Furthermore, states have discretion to adopt general policies that affect the 

application and implementation of WQS (40 CFR 131.13). There are many applications 

of criteria in Florida’s water quality programs. Therefore, EPA believes that it is not 

 80 Federal Register, Vol. 75, No. 233, 75762, December 6, 2010. Water Quality Standards for the State of 

Florida’s Lakes and Flowing Waters.
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necessary for purposes of this proposed rule to enumerate each of them, nor is it 

necessary to restate any otherwise generally applicable requirements.

It is important to note that no existing TMDL for waters in Florida will be 

rescinded or invalidated as a result of finalizing this proposed rule, nor will this proposed 

rule when finalized have the effect of withdrawing any prior EPA approval of a TMDL in 

Florida. Neither the CWA nor EPA regulations require TMDLs to be completed or 

revised within any specific time period after a change in water quality standards occurs. 

TMDLs are typically reviewed as part of states’ ongoing water quality assessment 

programs. Florida may review TMDLs at its discretion based on the State’s priorities, 

resources, and most recent assessments. NPDES permits are subject to five-year permit 

cycles, and in certain circumstances are administratively continued beyond five years. In 

practice, States often prioritize their administrative workload in permits. This 

prioritization could be coordinated with TMDL review. Because current nutrient TMDLs 

were established to protect Florida's waters from the effects of nitrogen and phosphorus 

pollution, the same goal as EPA's numeric nutrient criteria, the Agency believes that, 

absent specific new information to the contrary, it is reasonable to presume that basing 

NPDES permit limits on those TMDLs will result in effluent limitations as stringent as 

necessary to meet the federal numeric nutrient criteria.

IV. Under What Conditions Will Federal Standards Be Either Not Finalized or

Withdrawn?

Under the CWA, Congress gave states primary responsibility for developing 

and adopting WQS for their navigable waters. (See CWA section 303(a)-(c)). EPA is 
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proposing numeric nutrient criteria for flowing waters outside the South Florida Region

not covered by the State of Florida’s Rule and DPVs for unimpaired lakes to meet the 

Agency’s obligations under the Consent Decree. EPA notes if Florida’s Rule will not take 

effect due to subsection 62-302.531(9), F.A.C., EPA would expect to finalize the criteria 

in this proposed rulemaking for all flowing waters (i.e., streams) located outside of the 

South Florida Region that are designated as either Class I or Class III. EPA solicits 

comment on this potential outcome. EPA recognizes that Florida has exercised the 

option to adopt and submit to EPA numeric nutrient criteria for some of the State’s Class 

I and many of the State’s Class III waters and EPA has approved those criteria as 

consistent with CWA section 303(c) and implementing regulations at 40 CFR part 131.

Consistent with CWA section 303(c)(4), EPA does not intend to proceed with the final 

rulemaking for those waters for which EPA has approved Florida’s criteria, provided that 

the newly approved State water quality standards will be allowed to go into effect, FDEP 

will be allowed to implement them consistent with their Implementation Document, and, 

with respect to numeric DPVs, that the district court modifies the Consent Decree 

consistent with EPA’s amended Determination that numeric DPVs are not necessary to 

meet CWA requirements in Florida.

EPA is not obligated under the Consent Decree to promulgate regulations 

setting forth numeric nutrient criteria in all Class I and III lakes and flowing waters if the 

State of Florida submits and EPA approves new or revised WQS for these waterbodies. 

EPA approved such revisions on November 30, 2012 and is in discussions with Florida 

regarding waters not covered by the State’s numeric nutrient criteria. Comment [MS30]: Accepted addition with 

removal of the word “such”.
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Pursuant to 40 CFR §131.21(c), if EPA does finalize this proposed rule, the 

EPA-promulgated WQS would be applicable WQS for purposes of the CWA until EPA 

withdraws the federally-promulgated standard. Withdrawing the Federal standards for the 

State of Florida would require rulemaking by EPA pursuant to the requirements of the 

Administrative Procedure Act (5 U.S.C.551 et seq.). EPA would undertake such a 

rulemaking to withdraw the Federal criteria when EPA is assured that numeric nutrient

criteria that fully meet the requirements of section 303(c) of the CWA and EPA’s 

implementing regulations at 40 CFR part 131 are in effect.

Among the newly-approved state water quality standards are numeric criteria for 

nutrients that apply to a set of streams, as that term is specifically defined in the newlyapproved state water quality standards. Under the Consent Decree, EPA is relieved of its 

obligation to propose numeric criteria for nutrients for any waters for which once after

FDEP submits and EPA approves new or revised water quality standards before EPA 

proposesfor lakes and flowing waters. Thus, under normal circumstances, EPA would be 

clearly relieved of its obligation to propose numeric criteria for nutrients in streams

Florida covered in its newly-approved state water quality standards. However, another 

EPA notes that a provision included in Florida’s Rule, specifically subsection 62-

302.531(9), F.A.C., casts some doubt as to whether the newly approved state water 

quality standards will go into effect if EPA proposes and promulgates numeric nutrient 

criteria for streams not covered by the newly approved State water quality standards. 

Therefore, it is unclear whether an EPA’s proposal to “gap fill”, or establish numeric 

criteria for nutrients for Florida streams that FDEP does not cover in its Rule, would 

trigger 62-302.531(9), F.A.C. and result in Florida’s streams criteria not taking effect.

Comment [MS31]: Suggest using “after”.

Formatted: Font: 12 pt, Strikethrough

Comment [MS32]: Rejected addition of “lakes 

and flowing waters”. EPA disagrees w/ OIRA's 

addition. EPA’s Consent Decree extends beyond 

just lakes and streams. Accepting this change would 

result in a statement that implies the CD only applies 

to streams.

Formatted: Strikethrough

Comment [MS33]: Accepted strikeout

Comment [MS34]: Accepted edit.

Comment [MS35]: We do not have the specifics 

to make adjustments in this section at this time.
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In addition, due to a recent administrative challenged filed in the State of Florida 

Department of Administrative Hearings, there is uncertainty as to whether FDEP will be 

able to implement its newly approved state water quality standards consistent with 

FDEP’s “Implementation of Florida’s Numeric Nutrient Standards” (Implementation 

Document). EPA approved portions of Florida’s new or revised water quality standards 

based on the Agency’s understanding that FDEP will implement the streams criteria as 

provided in its Implementation Document. . Thus, EPA approved portions of Florida’s 

new or revised water quality standards subject to the State being able to implement them 

as provided in its Implementation Document. If, as a result of legal challenge, FDEP is 

unable to implement its Rule as provided in its Implementation Document, EPA would 

intend to revisit portions of its November 30, 2012 approval of Florida’s new or revised 

water quality standards. EPA has therefore reserved its authority to withdraw or modify 

portions of that approval.

In light of the above, EPA seeks comment on finalizing a rule that applies EPA’s 

streams criteria to streams meeting EPA’s definition of “stream” that are not covered 

under Florida’s numeric interpretation of narrative nutrient criteria at 62-302.531(2)(c), 

F.A.C. This would serve to fill gaps in coverage if Florida’s streams criteria are in effect, 

or apply to all streams if Florida’s streams criteria are not in effect for any reason, 

including those mentioned above. EPA’s current understanding is that it is obligated to 

propose numeric criteria in streams not covered by 62-302.531(2)(c) F.A.C. under the 

consent decree. EPA acknowledges that it is possible that there may be approaches that 

are similarly protective of designated uses in a subset of the uncovered Class III waters 

and seeks comment on alternatives.

Formatted: Font: 12 pt, Strikethrough

Comment [MS36]: Accepted strikeout.

Formatted: Strikethrough

Formatted: Font: 12 pt, Strikethrough

Comment [MS37]: Accepted strikeout.

Comment [MS38]: Accepted strikeout

Comment [MS39]: EPA recognizes this is 

repetitive, but feels it is necessary in order to be very 

clear and minimize confusion.
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EPA also seeks comment on alternative “gap filling” measures for waters not 

covered by numeric nutrient criteria in the State of Florida’s rule. Florida recently 

submitted and EPA approved new or revised WQS for Class I and III lakes and flowing 

waters. Under the Florida rule, a narrative nutrient standard would continue to provide 

in-stream protection to some Class III waters (e.g., non-perennial water segments, tidally 

influenced segments; and ditches, canals and other conveyances that are man-made or 

predominantly channelized or physically altered, are used primarily for water 

management purposes, and have marginal or poor stream habitat components), and these 

waters would benefit from improved protection of downstream waters in Florida’s 

revised WQS.

Finally, as described in EPA’s November 30, 2012 approval of Florida’s new or 

revised water quality standards, while EPA believes that the provisions addressing 

downstream protection will provide for quantitative approaches to ensure the attainment 

and maintenance of downstream waters consistent with 40 CFR 131.10(b), the provisions 

themselves, however, do not consist of numeric values. Because EPA is currently subject 

to a Consent Decree deadline to sign a rule proposing numeric downstream protection 

values (DPVs) for Florida by November 30, 2012, EPA is proposing numeric DPVs to 

comply with the Consent Decree. However, EPA has amended its January 2009 

determination to specify that numeric criteria for downstream protection are not 

necessary and that quantitative approaches designed to ensure the attainment and 

maintenance of downstream water quality standards, such as those established by Florida, 

are sufficient to meet CWA requirements. As such, EPA will ask the court to modify the 

Comment [MS40]: Addition rejected. The 

would violate the determination and consent decree. 

EPA’s determination addressed the need for numeric 

nutrient criteria, and EPA remains focused on this 

approach. It would not be helpful to ask for 

comment on something contrary to what we’re 

required to do.
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Consent Decree consistent with the Agency’s amended determination, i.e., to not require 

EPA to promulgate numeric DPVs for Florida. Accordingly, EPA approved the State’s 

downstream protection provisions subject to the district court modifying the Consent 

Decree to not require EPA to promulgate numeric DPVs for Florida. If the district court 

agrees to so modify the Consent Decree, EPA will not promulgate numeric DPVs for 

Florida. However, if the district court declines to so modify the Consent Decree, EPA 

would intend to promulgate numeric DPVs for Florida and would also expect to revisit its 

November 30, 2012 approval of the State Rule’s downstream protection provisions to 

modify or withdraw its approval. Therefore, EPA has also reserved its authority to do so 

in its approval document.

V. Statutory and Executive Order Reviews 

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: 

Improving Regulation and Regulatory Review

Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993), this action is 

a "significant regulatory action.” Accordingly, EPA submitted this action to the Office of 

Management and Budget (OMB) for review under Executive Orders 12866 and 13563 

(76 FR 3821, January 21, 2011) and any changes made in response to OMB 

recommendations have been documented in the docket for this action.

B. Paperwork Reduction Act
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This action does not impose an information collection burden under the 

provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. Burden is defined at 5 

CFR §1320.3(b). It does not include any information collection, reporting, or recordkeeping requirements.

C. Regulatory Flexibility Act 

The Regulatory Flexibility Act (RFA) generally requires an agency to prepare a 

regulatory flexibility analysis of any rule subject to notice and comment rulemaking 

requirements under the Administrative Procedure Act or any other statute unless the 

agency certifies that the rule will not have significant economic impact on a substantial 

number of small entities. Small entities include small businesses, small organizations, and 

small governmental jurisdictions.

For purposes of assessing the impacts of this action on small entities, small 

entity is defined as: (1) A small business as defined by the Small Business 

Administration's (SBA) regulations at 13 CFR §121.201; (2) a small governmental 

jurisdiction that is a government of a city, county, town, school district or special district 

with a population of less than 50,000; and (3) a small organization that is any not-forprofit enterprise that is independently owned and operated and is not dominant in its 

field.

Under the CWA WQS program, states must adopt WQS for their waters and 

must submit those WQS to EPA for approval; if the Agency disapproves a state standard 

and the state does not adopt appropriate revisions to address EPA’s disapproval, EPA 

must promulgate standards consistent with the statutory requirements. EPA also has the 

authority to promulgate WQS in any case where the Administrator determines that a new 
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or revised standard is necessary to meet the requirements of the Act. These state 

standards (or EPA-promulgated standards) are implemented through various water 

quality control programs including the NPDES program, which limits discharges to 

navigable waters except in compliance with an NPDES permit. The CWA requires that 

all NPDES permits include any limits on discharges that are necessary to meet applicable 

WQS.

Thus, under the CWA, EPA’s promulgation of WQS establishes standards that 

the State implements through the NPDES permit process. The State has discretion in 

developing discharge limits, as needed to meet the standards. This proposed rule does not 

itself establish any requirements that are applicable to small entities. As a result of this 

action, the State of Florida will need to ensure that permits it issues include any 

limitations on discharges necessary to comply with the standards established in the 

proposed rule. In doing so, the State will have a number of choices associated with permit 

writing. While Florida’s implementation of the rule may ultimately result in new or 

revised permit conditions for some dischargers, including small entities, EPA’s action, by 

itself, does not impose any of these requirements on small entities; that is, these 

requirements are not self-implementing. Thus, I certify that this rule will not have a 

significant economic impact on a substantial number of small entities.

D. Unfunded Mandates Reform Act

This proposed rule contains no Federal mandates under the regulatory 

provisions of Title II of the Unfunded Mandates Reform Act for state, local, or tribal 

governments or the private sector. The State may use these resulting water quality criteria 
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in implementing its water quality control programs. This proposed rule does not regulate

or affect any entity and, therefore, is not subject to the requirements of sections 202 and 

205 of UMRA.

EPA determined that this proposed rule contains no regulatory requirements 

that might significantly or uniquely affect small governments. Moreover, WQS, including 

those promulgated here, apply broadly to dischargers and are not uniquely applicable to 

small governments. Thus, this proposed rule is not subject to the requirements of section 

203 of UMRA.

E. Executive Order 13132 (Federalism)

This action does not have federalism implications. It will not have substantial 

direct effects on the states, on the relationship between the national government and the 

states, or on the distribution of power and responsibilities among the various levels of 

government, as specified in Executive Order 13132. EPA’s authority and responsibility to 

promulgate Federal WQS when state standards do not meet the requirements of the CWA 

is well established and has been used on various occasions in the past. The proposed rule 

will not substantially affect the relationship between EPA and the states and territories, or 

the distribution of power or responsibilities between EPA and the various levels of

government. The proposed rule will not alter Florida’s considerable discretion in 

implementing these WQS. Further, this proposed rule will not preclude Florida from 

adopting WQS that EPA concludes meet the requirements of the CWA, after 

promulgation of the final rule, which would eliminate the need for these Federal 
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standards and lead EPA to withdraw them. Thus, Executive Order 13132 does not apply 

to this proposed rule.

Although section 6 of Executive Order 13132 does not apply to this action, EPA 

had extensive communication with the State of Florida to discuss EPA’s concerns with 

the State’s water quality criteria and the Federal rulemaking process. In the spirit of 

Executive Order 13132, and consistent with EPA policy to promote communications 

between EPA and state and local governments, EPA specifically solicits comment on this 

proposed rule from State and local officials.

F. Executive Order 13175 (Consultation and Coordination with Indian Tribal 

Governments)

Subject to the Executive Order 13175 (65 FR 67249, November 9, 2000) EPA 

may not issue a regulation that has tribal implications, that imposes substantial direct 

compliance costs, and that is not required by statute, unless the Federal government 

provides the funds necessary to pay the direct compliance costs incurred by tribal 

governments, or EPA consults with tribal officials early in the process of developing the 

proposed regulation and develops a tribal summary impact statement.

During its previous rulemaking and development of water quality standards for 

Florida’s lakes and flowing waters, EPA concluded that the rule81 may have tribal 

implications. Ultimately, however, EPA felt that the rule would neither impose 

substantial direct compliance costs on tribal governments, nor preempt Tribal law.

Therefore, EPA met with the Seminole Tribe on January 19, 2010 and requested an 

 81 75 FR 75762, December 6, 2010. Water Quality Standards for the State of Florida’s Lakes and Flowing 

Waters.
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opportunity to meet with the Miccosukee Tribe to discuss EPA's rule, although a meeting 

was never requested by the Tribe.

Because this current proposal re-proposes the same numeric nutrient criteria with 

further explanation on how the criteria will ensure the protection of the Florida’s 

designated uses by avoiding harmful changes in nutrient levels, and provides for the same 

approaches for determining DPVs as in the final rule with some additional flexibility, 

EPA determined that tribal consultation will not be needed. However, EPA will 

specifically solicit additional comment on this proposed rule from tribal officials during 

the public comment period.

G. Executive Order 13045 (Protection of Children From Environmental Health and 

Safety Risks)

This action is not subject to EO 13045 (62 FR 19885, April 23, 1997) because it is 

not economically significant as defined in EO 12866, and because the Agency's 

promulgation of this rule will result in the reduction of environmental health and safety 

risks that could present a disproportionate risk to children.

H. Executive Order 13211 (Actions That Significantly Affect Energy Supply, Distribution, 

or Use)

This rule is not a “significant energy action” as defined in Executive Order 13211, 

“Actions Concerning Regulations That Significantly Affect Energy Supply,

Distribution, or Use” (66 FR 28355 (May 22, 2001)), because it is not likely to have a 

significant adverse effect on the supply, distribution, or use of energy.

I. National Technology Transfer Advancement Act of 1995
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Section 12(d) of the National Technology Transfer and Advancement Act of 1995 

(“NTTAA”), Public Law 104–113, section 12(d) (15 U.S.C. 272 note) directs EPA to use 

voluntary consensus standards in its regulatory activities unless to do so would be 

inconsistent with applicable law or otherwise impractical. Voluntary consensus standards 

are technical standards (e.g., materials specifications, test methods, sampling procedures, 

and business practices) that are developed or adopted by voluntary consensus standards 

bodies. The NTTAA directs EPA to provide Congress, through OMB, explanations when 

the Agency decides not to use available and applicable voluntary consensus standards.

This proposed rulemaking does not involve technical standards. Therefore, EPA is 

not considering the use of any voluntary consensus standards.

J. Executive Order 12898 (Federal Actions To Address Environmental Justice in 

Minority Populations and Low-Income Populations)

Executive Order (EO) 12898 (59 FR 7629, Feb. 16, 1994) establishes Federal 

executive policy on environmental justice. Its main provision directs Federal agencies, to 

the greatest extent practicable and permitted by law, to make environmental justice part 

of their mission by identifying and addressing, as appropriate, disproportionately high 

and adverse human health or environmental effects of their programs, policies, and 

activities on minority populations and low-income populations in the United States.

EPA has determined that this proposed rule does not have disproportionately high 

and adverse human health or environmental effects on minority or low-income 

populations because it will afford a greater level of protection to both human health and
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the environment if these numeric nutrient criteria are promulgated for Class I and Class 

III waters in the State of Florida.

List of Subjects in 40 CFR Part 131

Environmental protection, Florida, Nitrogen and phosphorus pollution, Nutrients, Water 

quality standards.

Dated: November 30, 2012

Lisa P. Jackson,

Administrator.

For the reasons set out in the preamble, 40 CFR part 131 is proposed to be amended as 

follows:
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PART 131 – WATER QUALITY STANDARDS

1. The authority citation for part 131 continues to read as follows:

Authority: 33 U.S.C. 1251 et seq.

Subpart D-[Amended]

2. Section 131.43 is amended by:

a. Revising (c)(2)(i).

b. Revising paragraph (c)(2)(ii)(C). 

c. Revising paragraph (f).

The revisions read as follows:

§ 131.43 Florida.

* * * * *

(c) * * *

(2) Criteria for streams.

(i) The applicable instream protection value (IPV) criteria for total nitrogen (TN) 

and total phosphorus (TP) for streams within each respective nutrient watershed region 

are shown on Table 2.

Table 2:
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Nutrient Watershed Region

Instream Protection Value Criteria

TN (mg/L) * TP (mg/L) *

Panhandle West a 0.67 0.06

Panhandle East b 1.03 0.18

North Central c 1.87 0.30

West Central d 1.65 0.49

Peninsula e 1.54 0.12

Watersheds pertaining to each Nutrient Watershed Region (NWR) were based principally on the NOAA 

coastal, estuarine, and fluvial drainage areas with modifications to the NOAA drainage areas in the West 

Central and Peninsula Regions that account for unique watershed geologies. For more detailed information 

on regionalization and which WBIDs pertain to each NWR, see the Technical Support Document.

a Panhandle West region includes: Perdido Bay Watershed, Pensacola Bay Watershed, Choctawhatchee 

Bay Watershed, St. Andrew Bay Watershed, Apalachicola Bay Watershed. b Panhandle East region includes: Apalachee Bay Watershed, and Econfina/Steinhatchee Coastal Drainage 

Area.

c North Central region includes the Suwannee River Watershed.

d

West Central region includes: Peace, Myakka, Hillsborough, Alafia, Manatee, Little Manatee River 

Watersheds, and small, direct Tampa Bay tributary watersheds south of the Hillsborough River Watershed. 

e Peninsula region includes: Waccasassa Coastal Drainage Area, Withlacoochee Coastal Drainage Area, 

Crystal/Pithlachascotee Coastal Drainage Area, small, direct Tampa Bay tributary watersheds west of the 

Hillsborough River Watershed, Sarasota Bay Watershed, small, direct Charlotte Harbor tributary 

watersheds south of the Peace River Watershed, Caloosahatchee River Watershed, Estero Bay Watershed, 

Kissimmee River/Lake Okeechobee Drainage Area, Loxahatchee/St. Lucie Watershed, Indian River 

Watershed, Daytona/St. Augustine Coastal Drainage Area, St. John’s River Watershed, Nassau Coastal 

Drainage Area, and St. Mary’s River Watershed. * For a given water body, the annual geometric mean of TN or TP concentrations shall not exceed the 

applicable criterion concentration more than once in a three-year period.

(ii) Criteria for protection of downstream lakes.

(A) * * *

(B) * * *

(C) When the State or EPA has not derived a DPV for a stream pursuant to 

paragraph (c)(2)(ii)(B) of this section, and where the downstream lake attains the 

applicable chlorophyll-a criterion and the applicable TP and/or TN criteria, then the DPV 

for TN and/or TP will be determined using any of the following options: For the first 

option, the DPV for TN and/or TP applicable at the pour point to the lake is the 

applicable TN and/or TP criteria for the downstream lake codified in 40 CFR

§131.43(c)(1), similar to paragraph (c)(2)(ii)(D) of this section. For the second option, the 
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DPV for TN and/or TP applicable at the pour point of the receiving lake is found in Table 

3.

Table 3:

Default Option 2

Lake Class TN DPV (mg/L) TP DPV (mg/L)

Colored Lakes 1.59 0.11

Clear, High 

Alkaline Lakes 1.40 0.09

Clear, Low 

Alkaline Lakes 0.87 0.06

For the third option, the DPV for TN and/or TP applicable at the pour point to the lake is 

computed using TN and TP data from the stream discharging into the lake coincident in 

time with the period of record when the lake was attaining all applicable nutrient criteria 

pursuant to 40 CFR §131.43(c)(1). These default approaches supplement EPA’s 

promulgated DPVs for the protection of downstream lakes in paragraphs (c)(2)(ii)(B) and 

(D) of this section.

(f) Effective date. This section is effective January 6, 2013 except for 

§131.43(c)(2)(i) and 131.43(c)(2)(ii)(C), which are effective [INSERT DATE 60 DAYS 

FROM PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER] and 

§131.43(e), which is effective February 4, 2011.

Comment [MS41]: EPA added a sentence in the 

preamble. See page 25. The reader can go to the link 

for more info including how it relates to this 

proposal.

Comment [MS42]: EPA checked on this to be 

certain of the proper format and style.