CHAPTER 2 

Issue Category: Proposed Numeric Nutrient 

Criteria for the State of Florida's Springs 

and Clear Streams 

Pages 3953 - 4049 

Response to Public Comments 

Water Quality Standards for the State of Florida's 

Lakes and Flowing Waters 

November 14, 2010 

40 CFR Part 131 

Docket #: EPA-HQ-OW-2009-0596 

This document is part of a larger document 
Chapter 2 - Comment Documents Springs and Clear Streams 

III.D - SPRINGS AND CLEAR STREAMS 

No Comments are Applicable to this Issue Category, and Thus No Response is Necessary. 

III.D.1 - PROPOSED NUMERIC NUTRIENT CRITERIA FOR SPRINGS 

AND CLEAR STREAMS 

Comment ID 0580.001.002 

Author Name: Browning D. 

Organization: 

We need a peer review system of scientific studies used to deflect public attention away from point source pollution by 

FDEP licensed utilities. FDEP is conflicted in its role of utility discharge protector, and environmental protector. The 

harm from nitrate discharge is clear at our springs, however study after study deflects blame away from utility dumping. 

When found discharging pollutants, the utilities and FDEP explain that it would cost millions, even billions of dollars to 

stop the pollution. That may be true, but at least with EPA standards we would know how much pollution is coming from 

the utilities. 

Dear Sir, Florida is suffering under an extremely dysfunctional and deceptive system of Storm Water Runoff and Sewer 

Effluent/Sludge disposal by protected utilities. We believe that a lack of standards is at the heart of Florida pollution 

problems. Historically, DOT and City, County utilities have simply sent sewer effluent downhill, or piped under ground, 

in the hopes it would not come back. In Florida, our karst geology allows under ground conduits to carry pollution away 

to springs and on to rivers. In coastal areas pipes simply empty into the Ocean or Gulf. In inland areas pipes simply 

empty into the Aquifer. 

Historically, the Floridan aquifer's capacity is so vast and the coastal waters are so large, that dumping could occur with 

hopes the receiving waters could take the load. We have arrived at a point where a negative impact is showing up, 

especially in our springs, and FDEP has developed a program of public relations to deflect blame from old Bad 

Management Practices. (BMP's) The deception is now affecting our planning process causing a damper on economic 

growth. We believe more honesty by FDEP, and better universal standards will stop the downhill economic conditions 

Florida is experiencing with tax revenues. While the world, and county are in economic difficulty, we in Florida are 

adding to the economic downturn. Please apply a single standard for dumping nitrates. A single standard for both the 

people and utilities is better than a double standard. Even if the nitrate standard is set high at the level FDEP currently 

approves, at least we would all be able to understand why our waters are becoming polluted. 

While the public understands utilities must discharge a large volume of nitrogen storm sewer and processed sewer 

effluent daily, more honesty can be achieved with actual nitrogen standards. Currently Utilities are FDEP approved to 

discharge along with FDOT, and FDEP has developed an elaborate hoax to cover up the resulting problems. The same 

scientist are hired year after year to certify that there is no Point Source Pollution occurring, and the pollution is coming 

from random soaking in of nitrates across florida. For good reason the public is beginning to distrust their government. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Florida in effect has no set standard for nitrates. The TMDL total maximum daily load regulates the harm done to the 

receiving water body, not the pollution discharged. 70 mph is the standard used to control speed on our Florida Federal 

Highways generally, imagine a system where total daily speed was used to control speeders. If there doesn't seem to 

be a problem that corvette doing 150 mph would be lawful. Imagine instead of .08% standard, we used a TMBL system 

for impaired drivers. A Total Daily Maximum Load for drinking drivers would be a Narrative Standard where the amount 

of Alcohol is flexible, if the driver looks alright, he or she is legal to operate a vehicle. 

Comment ID 0580.001.007 

Author Name: Browning D. 

Organization: 

FDEP and participating water districts use the vast Floridan Aquifer and Karst features to drain urban runoff and 

discharged sewer effluent to Florida's Springs. Because most discharged waste is under the Drinking Water level of 

10.0 mg/l for nitrogen, FDEP is able to work a very clever scam of dumping at 10 part per million and higher, while 

pretending to be concerned with the resulting 1 or 2 parts per million reaching our springs. 

By using deceptive terms FDEP is able to fool the public. Example: A drain pipe to the drinking water aquifer is termed 

a Beneficial Gravity Recharge Outfall, if used by an approved utility. (See City of Ocala Storm Sewer Reports to EPA) A 

Sinkhole used to directly drain Urban Storm Sewer is called by FDEP, an important grandfathered or newly created 

aquifer recharge function. Processed Sewer Effluent discharge is called Beneficial Aquifer Recharge. Florida's Public 

are being deceived and the public trust is being broken. The Same Standard for Nitrates should apply to FDEP as 

applies to private citizens. Only by using a Federal Standard can Floridians trust that FDEP is not using a special "high 

pollution standard" for favored FDEP regulated utilities. FDEP, FDOT, and FDCA are working together to distract the 

trusting public with an elaborate scheme of Utility Discharge of Pollutants, covered up by an elaborate Springs/Aquifer 

public relations program. Example of FDEP sponsored deception. Only the EPA can oversee the discharge of high 

nutrient loads, while making it sound beneficial and blaming the public as the source of the pollution. 

ALTERNATIVE WATER SUPPLY PLANNING 

To address these potential problems before they become critical, SJRWMD is investigating the feasibility of several 

alternative water supply strategies, including artificial recharge of the Floridan aquifer. 

ARTIFICIAL RECHARGE INVESTIGATIONS 

Artificial recharge using gravity recharge (drainage) wells is a technically feasible, long established practice in central 

Florida, particularly in Orange and Seminole counties. Drainage wells in this area were originally constructed to provide 

urban drainage and lake level control; however, these wells also provide an important aquifer recharge function. 

THE ROLE OF ARTIFICIAL RECHARGE WELLS IN CENTRAL FLORIDA 

In central Florida, drainage wells generally connect a surface water feature with the upper Floridan aquifer. Historically, 

their primary purpose has been to provide surface drainage and to prevent flooding in closed surface basins. Drainage 

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Chapter 2 - Comment Documents Springs and Clear Streams 

wells operate by gravity. They are technically feasible in areas where the surface water elevation is greater than the 

potentiometric elevation of a transmissive receiving aquifer. These conditions exist throughout much of the developed 

portions of central Florida, including Orlando. The surface water source for a recharge well can be direct surface runoff, 

such as street or urban drainage, or indirect surface runoff, such as a lake, storm-water detention pond, or wetland 

outflow. By far, the most common existing drainage well applications in central Florida are street drainage and lake level 

control. 

Comment ID 0585.001.002 

Author Name: Tomaski N. 

Organization: 

I support strict regulation of groundwater levels of nitrogen in springsheds, the land area within the water basin which 

filters the groundwater that contributes to the discharge of a spring. 

I advocate determining and adopting minimum flow levels to protect the natural flow of our springs from over-pumping. 

These levels should be based on historic flow levels. 

A master storm water management plan needs to be established for springsheds. 

Florida will need to require efficient septic systems to remove nitrogen to at least 10mg per liter in effluent. The normal 

level of nitrogen is approximately .01mg per liter. 

Florida will need to restrict artificial fertilizer use in the springshed for nitrogen and phosphorus. 

Florida will need to establish the total maximum daily load, which is the amount of pollutant that can be legally 

discharged from all sources into a water body. 

Florida will need a basin management action plan, a blueprint for correcting pollution in a water body. 

I support the establishment of a Florida springs protection trust fund. By placing a fee on bottled water, the proceeds 

would be used to upgrade waste removal systems in a springshed and purchase vulnerable lands in the springshed. 

Comment ID 0603.001.001 

Author Name: Bird C. 

Organization: Alachua County 

Florida needs numeric standards for springs to prevent adverse impacts due to nutrient loading and algal growth 

USEPA and FDEP need to better account for the impact of increased water consumptive use on water quality. 

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Comment ID 0934.001.003 

Author Name: Louda J. 

Organization: 

What can and cannot be reasonably done? Let's look at deep spring waters- Zephyrhills water has gone fro about 40 to 

around 55 ppb in the last decade or so. 

Comment ID 0940-1.001.002 

Author Name: Scally C.
 

Organization: E.O. Wilson Biophilia Center
 

Springs have sustained serious damage in Florida as a result of nitrogen pollution. The proposed nutrient criteria for 

springs, spring runs and clear streams should be revised based on the evidence that is already in the record showing 

that EPA should adopt nitrogen standards no higher than 230 ug/L. 

Comment ID 0940-1.001.003 

Author Name: Scally C.
 

Organization: E.O. Wilson Biophilia Center
 

There should be no allowance for upward modifications of the nitrogen and phosphorus criteria based on samples 

showing that, despite high nitrogen and phosphorus levels, chlorophyll levels are tolerable. 

Comment ID 0946.001.001 

Author Name: Dickinson J. 

Organization: Forest Management Trust 

EPA, protect our springs! We need clear science-based quantitative water quality standards. After visiting legislators in 

Tallahasse I realize that EPA is basically our only hope of protecting our springs. You have strong grass-roots support. 

Comment ID 1140.001.004
 

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Author Name: Hilliard D. 

Organization: 

An example would be your -- your springs proposal, .35 milligrams per liter. Now, on the Withlacoochee River, which is 

a conundrum in its own right, it's a relatively high-water water -- high-quality water body until it reaches the outflow of 

the Rainbow Springs, where about 1.8 milligrams per liter of nitrogen is introduced. And it goes through Lake 

Rousseau, where it's filtered to some degree with -- by aquatic vegetation, comes over the spillway into the lower river. 

Comment ID 1140.001.005 

Author Name: Hilliard D. 

Organization: 

And we've been actually afforded through the docket on this case water quality summaries that indicate nitrogen levels 

ranging in the .25 to .85 range over the last couple of years. The lower level is beset with algae blooms and Lyngbya. 

1994, the organization was instrumental in the designation of that water body as an outstanding Florida water. It is not 

as outstanding today as it was then. And the problem we see, the D.E.P. does not have the framework, does not have 

the legal basis to address these things. This is why we support the numeric content issue. 

Comment ID 1140.001.006 

Author Name: Hilliard D. 

Organization: 

To digress slightly on the issue of -- of the springs proposal, I think that it is a reasonable compromise in what you're 

looking at here, the historic background of Silver Springs back in the time when I first saw it was about 1/2 milligram per 

liter, it was a vibrant body, and that's -- I remember it from that visit one time. It's not like that today. 

Banning Springs is point -- is 8 milligrams per liter right now, it's the worst on -- on Florida's list. Levy County 

Commission recently passed a nonbinding resolution against the process that you all are -- are in charge of here, which 

we found somewhat conflicted because that's one of their largest tourist attractions. 

With that said, the springs that feed Crystal River in Citrus County are generating, as we understand from the 

Southwest Florida Water Management District, are generating nitrogen loads in the range of .35 milligrams per liter, and 

it is heavily impacted with Lyngbya and -- and other algaes. 

I don't know that the answer to all this is clear. This is the science that you folks have to work out. Possibly specific 

determinations for specific basis and rivers and such would be appropriate. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1165.001.003 

Author Name: Commenter Anonymous 

Organization: 

I am especially pleased that water-quality in Florida springs will be addressed, as such springs are a unique Florida 

phenomenon which have been suffering lately from deterioraed water quality and quantity. 

Comment ID 1203.001.003 

Author Name: Crooks A. 

Organization: 

Now these places I love are in trouble. Blue Springs, where hundreds of endangered manatees take refuge each winter, 

apparently has shown nitrate pollution elevated to six times its natural level, which puts it on the list of the most 

impaired springs in the state. 

There is nothing like swimming in a crystal clear spring with schools of gar swimming past you, snorkeling over the 

spring head. 

If we lose access to our springs due to pollution, it would be a great loss. So I encourage the E.P.A. to adopt numeric 

criteria to protect our springs. 

Comment ID 1311.001.004 

Author Name: Long A. 

Organization: 

The two first manatee springs in my neighborhood, Manatee and Fanning, already have high nutrient levels and have 

significantly impaired ecosystems. And that's according to the Department of Environmental Protection. What used to 

be lush, diverse subaquatic vegetation with varied invertebrate and vertebrate communities is now a biological desert of 

nuisance filamentous algal mass. 

Comment ID 1311.001.006 

Author Name: Long A. 

Organization: 

I want to start with the worst victims. The following springs have exceeded the EPA safe drinking water standard of 10 

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Chapter 2 - Comment Documents Springs and Clear Streams 

milligrams per liter of nitrate nitrogen. In the recent past they vary from -- depending on rainfall and season. Convict 

Springs, Trail Springs, Fanning Springs. And it's so sad, these other springs have no name, they just have numbers. 

SUW 718971, SUW 725971, GIL 107972, and GIL 917971. 

The drinking water standard is 29 times the proposed criteria, and many of these dangerously polluted springs are used 

as swimming holes. Individual homes have wells in their spring sheds. 

Those seven springs are virtual point sources of pollution, but there are also ten springs on the Suwannee between 3 

and 8 milligrams per liter, 17 springs between 2 and 3 milligrams per liter, and over 66 springs that exceed 1 milligram 

per liter. It will be over a decade before the TMDL that's proposed begins to address those springs. 

Comment ID 1311.001.007 

Author Name: Long A. 

Organization: 

When I questioned the Department of Environmental Protection and the Department of Health about the dangerously 

polluted springs, I was told that since no one drinks out of them, the drinking water standard doesn't apply. Fanning 

Springs was the only dangerously polluted spring that was addressed by the TMDL plan. 

The FDEP and Suwannee River Water Management District don't appear to be overly concerned about these springs 

as few of the dangerously polluted ones have been tested regularly since a single test that was done back in 1997. If 

they have, the data is not available to the public. 

Comment ID 1352-1.001.127 

Author Name: Herr M. 

Organization: Polk County 

Springs and Clear Streams (40 FR Part 131 Section III.D) 

Background 

Florida's springs and spring runs (clear springs) are valuable for biological, recreational, economical, and aesthetic 

purposes. Under natural conditions their diverse biota is a function of naturally high water clarity. Two factors have been 

identified as major contributors to observed decreases in spring water quality: pollutant loading to groundwater, 

especially nitrate-nitrite nitrogen, and reduction in spring flow caused by groundwater withdrawals (EPA, 2010a, page 

126). Pollutant loadings result in a higher flux of nutrients into the spring, and reduced flows result in increased 

residence time of water in the ground and spring. 

A significant outcome of these factors is that algae and invasive plant species replace desirable native submerged 

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aquatic vegetation (SAV). Excessive algae growth may include both floating mats that shade the water and reduce light 

penetration, and periphyton growth on the hard surfaces, smothering native plants (EPA, 2010b, page 3-2). 

Comment ID 1352-1.001.187 

Author Name: Herr M. 

Organization: Polk County 

EPA proposes to require clear streams to meet the TN and TP targets for streams and rivers in addition to the nitratenitrite criterion. No supporting evidence has been provided in either the rule or the TSD that this piling on of additional 

numeric criteria will do anything to improve the health of clear streams. 

Comment ID 1695-1.001.006 

Author Name: Wiley N. 

Organization: Florida Fish and Wildlife Conservation Commission 

Springs and Clear Streams: 

The FWC fully supports the implementation of the nitrate-nitrite criterion to springs and clear streams. Reduction of both 

phosphorus and nitrogen (particularly nitrates and nitrites) loads is necessary to reduce the growth and expansion of 

macroalgal species that threaten the native fish and wildlife and plant communities, as well as the aesthetics, of these 

unique systems. 

Comment ID 1761-3.001.057 

Author Name: Merrill M. 

Organization: Hillsborough County 

2. EPA proposes to require clear streams to meet the TN and TP targets for streams and rivers in addition to the nitratenitrite criterion. No supporting evidence has been provided in either the rule or the TSD that this piling on of additional 

numeric criteria will do anything to improve the health of clear streams. It will, however, force communities, businesses, 

and state agencies to waste a great deal of money attempting to meet the requirement without corresponding benefit to 

the health of the stream. The nitrate-nitrite criteria as proposed, recognizes the nature of springs and how loads reach 

those springs through groundwater flow. The inclusion of phosphorus criteria, in addition, would not improve the overall 

health of these systems where it has been recognized that the need is for reductions in nitrogen. 

Comment ID 1768-1.001.023 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Author Name: Armingeon N. 

Organization: St. Johns River Keeper 

Springs 

• Springs have sustained serious damage in Florida as a result of nitrogen pollution. A third of the St. Johns River's flow 

is made up of spring flow. Higher nitrate levels in springs exacerbate the nutrient pollution problem. There is clear 

evidence that the NNS for springs is too high. The proposed nitrogen standard for springs, spring runs and clear 

streams should be revised, and EPA should adopt nitrogen standards no higher than 230 ug/L. 

Comment ID 1777-2.001.148 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

2. EPA proposes to require spring runs and clear streams to meet the TN and TP targets for streams and rivers in 

addition to the nitrate-nitrite criterion. No supporting evidence has been provided in either the rule or the TSD that this 

piling on of additional numeric criteria will do anything to improve the health of these systems. It will, however, force 

communities, businesses, and state agencies to waste a great deal of money attempting to meet the requirement 

without corresponding benefit to the health of the stream. The nitrate-nitrite criteria as proposed, recognizes the nature 

of springs and how loads reach those springs through groundwater flow. The inclusion of phosphorus criteria, in 

addition, would not improve the overall health of these systems where it has been recognized that the need is for 

reductions in nitrogen. 

Comment ID 1801-1.001.011 

Author Name: Green III K. 

Organization: St. Johns River Water Management District 

Specific Comments - Springs and Clear Streams 

As indicated in the attached report (attachment 2), the District believes that the proposed NOX criterion for Florida 

springs and "clear streams" (spring run streams) is appropriate for the protection of aquatic life and designated use. 

Comment ID 1920-1.001.013 

Author Name: Wise W. 

Organization: University of Florida on behalf of Earthjustice 

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Chapter 2 - Comment Documents Springs and Clear Streams 

THE CITY OF TALLAHASSEE SPRAY FIELD CASE 

32. From about 2005 to 2008, I worked as an expert consultant for Attorney General Charlie Crist on a controversy over 

the nutrient contamination of Wakulla Spring - the largest spring in the State of Florida. The case involved both nonpoint source and point source pollution. The point source pollution was the spray field for the City of Tallahassee's 

sewage treatment plant. Nutrient polluted water discharged onto the spray field traveled underground for several miles 

to Wakulla Springs where it contributed to triggering a nearly uncontrolled growth of slimy green algae and filamentous 

algae growths that occluded the entire Spring. 

33. I served as a representative of the Attorney General's Office in the mediation process during which the lawsuit was 

settled. One of the reasons the Attorney General intervened in the lawsuit was because of the serious decline in 

revenues of Wakulla Springs related business as a direct consequence of the nutrient pollution of the Spring. 

34. It is not just the environmental and economic value of Wakulla Springs that is being destroyed by nutrient pollution ­

spring systems statewide are being threatened by biological imbalances caused by excessive nutrients transported via 

groundwater.[17] 

[17] http://www.dep.state.fl.us/water/docs/2008_Integrated_Report.pdf at p. xiv and 

Comment ID 2030-1.001.003 

Author Name: Long A. 

Organization: 

I want to start with the worst victims. The following springs have exceeded the EPA safe drinking water standard of 10 

mg/L nitrate in the recent past: Convict Spring, Trail Spring, Fanning Spring, SUW718971, SUW725971, Gil107972, 

GIL917971. THAT'S GREATER THAN 10 mg/L. The drinking water standard is 29 times the proposed criteria. Many of 

these dangerously polluted sp rings are used as swimming holes by locals. Individual homes have private wells in their 

spring sheds. [strikeout: This is] These springs have been ignored. 

Those 7 springs are virtual point sources of pollution. in the TMDL process [strikeout: Those are the poster children] 

but there are also 10 springs between 3 and 8 mg/L, 17 springs that between 2 and 3 mg/L and over 66 springs that 

exceeded 1 mg/L. 

It will be over a decade before the ->current<- TMDL ->begins to<- address these springs. 

Comment ID 2030-1.001.009 

Author Name: Long A. 

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Organization: 

The two first magnitude springs in my neighborhood already have high nutrient levels and have significantly impaired 

ecosystems. What used to be lush, diverse sub-aquatic vegetation with varied invertebrate and vertebrate communities 

is now a biological desert of nuisance filamentous algal mats. 

Comment ID 2030-1.001.011 

Author Name: Long A. 

Organization: 

When I questioned the Department of Environmental Protection and Department of Health about the dangerously 

polluted springs, I was told that since no one drinks out of them the drinking water standard doesn't apply. Fanning 

Spring was the only dangerously polluted spring that was addressed by the current Total Maximum Daily Load. Plan. 

[strikeout: Enforcement will be vol] 

The FDEP and Suwannee River Water Management District don't appear to be overly concerned about these springs 

as few of the dangerously polluted springs have been tested regularly since a single test that was done back in 1997. If 

they have, the data isn't available to the public. [strikeout: When finalizing the rule in the case of clear, flowing springs ­

there should be no allowance for upward modifications of the nitrogen and phosphorous criteria based on samples 

showing that, despite high nitrogen and phosphorus levels, chlorophyll levels are tolerable.] 

Response 

Comment ID: 0585.001.002 

Response: EPA agrees with comments that support its efforts for developing criteria for springs and the protection of springsheds. 

While EPA appreciates the various suggestions for trying to address problems related to springs and springsheds, this rulemaking, 

deals only with the development and promulgation of nutrient criteria. Water quality standards, and EPA’s rule specifically, do not 

specify how to attain those standards. The Florida Department of Environmental Protection (FDEP) is the primary agency 

responsible for implementing Clean Water Act (CWA) programs in the State of Florida. As such, EPA defers to FDEP in 

administering applicable CWA programs consistent with CWA statutes and EPA’s implementing regulations. The State of Florida 

will determine how best to meet the standards in a way that meets the needs of its citizens and environment. 

Comment IDs: 0580.001.002, 0580.001.007, 0603.001.001, 0946.001.001, 1140.001.005, 1140.001.006, 1165.001.003, 

1203.001.003, 1311.001.004, 1311.001.006, 1311.001.007, 1352-1.001.127, 1695-1.001.006, 1801-1.001.011, 1920-1.001.013, 

2030-1.001.003, 2030-1.001.009, 2030-1.001.011 

Response: EPA agrees with comments that offer support for this rulemaking process, which includes springs. 

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Comment IDs: 0934.001.003, 1140.001.004 

Response: EPA notes these comments, which restate the technical findings from the proposed rule, and the scientific process that 

EPA undertook to derive criteria. 

Comment IDs: 0940-1.001.002, 0940-1.001.003, 1768-1.001.023 

Response: EPA disagrees with comments suggesting that the NO3+NO2 criterion for springs and associated spring runs should be 

higher or lower than 0.35 mg/L. Selection of the final criterion value required that EPA weigh different types of evidence, 

including both field and laboratory studies. The final criterion value of 0.350 mg/L is less than the value criterion value derived 

from field studies and greater than values observed from laboratory studies. EPA has made a selection designed to balance the 

uncertainty inherent in translating ideal laboratory conditions to the field versus uncertainty inherent in estimating stressor-response 

relationships from field data. See the final rule TSD for more information regarding EPA’s scientific support for its springs criteria. 

Comment IDs: 1352-1.001.187, 1761-3.001.057, 1777-2.001.148 

Response: After careful consideration and an evaluation of comments received regarding this issue, EPA has decided not to finalize 

the springs NO3+NO2 criterion in clear streams. EPA considers the numeric nutrient criteria it is finalizing in this rule for streams, 

including clear streams, to be protective of designated uses and scientifically defensible. EPA concluded that Florida’s streams, 

including clear streams, will also be protected from excessive inorganic nitrogen pollution by the NO3+NO2 criteria, where there 

are springs in the streams’ upstream watershed. 

III.D.2 - METHODOLOGY FOR DERIVING EPA’S PROPOSED 

CRITERIA FOR SPRINGS AND CLEAR STREAMS 

Comment ID 1063.001.005 

Author Name: Hecker J. 

Organization: Conservancy of Southwest Florida 

The proposed nitrate and nitrite criterion for springs and clear streams are based on a rational and robust approach of 

using extensive laboratory and field studies, determining levels where there are responses to algae from nutrient 

concentrations. 

Comment ID 1197.001.006 

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Author Name: Hecker J. 

Organization: Conservancy of Southwest Florida 

The proposed nitrate and nitrite criterion for springs and clear streams are based on a rational and robust approach of 

using extensive laboratory and field studies, determining levels where there are responses to algae to nutrient 

concentrations. 

Comment ID 1217-2.001.007 

Author Name: Voyles J. 

Organization: Mosaic Fertilizer LLC 

3. EPA improperly applies scientific conclusions reached for springs and spring runs to set criteria for clear streams. 

Clear streams are qualitatively different waterbodies than springs, and the scientific evidence EPA has developed to set 

criteria for springs are by their own terms not persuasive when applied to clear streams. Accordingly, the Rule should 

be revised to apply the springs criteria only to springs and spring runs, and clear streams should be governed by the 

criteria that apply to streams generally. 

Comment ID 1352-1.001.132 

Author Name: Herr M. 

Organization: Polk County 

Methodology 

EPA is not proposing total phosphorus (TP) criteria for springs because phosphorus has historically been present in 

Florida's springs, given the State's naturally phosphorus-rich geology and the documented lack of an increasing trend of 

phosphorus concentrations in most spring discharges. Also, EPA is not proposing chlorophyll a or water clarity criteria 

due to the lack of available data for these response variables in spring systems (EPA, 2010a, page 130). 

Comment ID 1352-1.001.133 

Author Name: Herr M. 

Organization: Polk County 

Methodology 

Further, scientific evidence shows a strong relationship between the thickness of periphyton algal biomass attached to 

substrate and nutrients in clear streams (those with color <40 PtCo units and canopy cover 40% which are comparable 

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to most waters found in springs and spring runs) (Stevenson et al., 2007). Benthic algal thickness has been shown to 

be highly dependent on nitrogen parameters (TN and total inorganic nitrogen), as opposed to phosphorus. EPA is 

therefore proposing to apply the nitrate-nitrite criteria derived for springs to clear streams as a measure to gauge 

anthropogenic contributions to TN (EPA, 2010a, page 131). 

Comment ID 1355-2.001.050 

Author Name: Barker V. 

Organization: Brevard County Board of County Commissioners 

Data Used to Develop the Criteria 

Much of the water quality and spring vegetation information used to develop the spring NNC criteria was obtained from 

sites in the northern part of the state, and the data used in the final analysis to develop the proposed criteria were all 

from the Suwannee River system. Although spring distribution is higher to the north, there are significant geological, 

climatic, and biological differences between the northern and central/southern portions of the state. A number of factors 

influence ground-water chemistry. These include the precipitation chemistry, surface conditions at the site of recharge, 

soil type in the recharge area, mineralogy and composition of the aquifer system, nature of aquifer system porosity and 

structure, flow path in the aquifer, residence time of the water in the aquifer, mixing of other waters in the aquifer 

system, and aquifer microbiology (Scott et al, 2004). The proposed rule and TSD present no documentation supporting 

the assumption that Suwannee River system spring data is representative of springs in different parts of the state, (e.g., 

Suwannee River, Weeki Wachee, Volusia Blue, and Warm Mineral Springs). 

Regional variability in spring water quality and response of vegetation should be reflected in the criteria. Regional 

differences in water quality are recognized in EPA's proposed stream and lake standards, and a similar analysis is 

warranted for springs, given the wide variation in state-wide conditions, especially between the Panhandle and 

Peninsula regions. 

Comment ID 1355-2.001.095 

Author Name: Barker V. 

Organization: Brevard County Board of County Commissioners 

Springs and Clear Streams 

• A spring run is defined as a free-flowing water body that receives more that 50% of its flow from a spring. However, it 

is not defined as to whether this determination is based on an instantaneous measurement, annual average, period of 

record average, or other measurement. 

• Much of the data used to develop the numeric nutrient criteria came from springs within a relatively limited spatial 

extent, i.e., primarily in the north-central region of the state. Given the wide variation across regions in such factors as 

geology, hydrology, and rainfall, no evidence was presented that spring water quality for different systems (e.g., 

Suwannee River, Weeki Wachee, Warm Mineral Springs, Volusia Blue) should respond similarly to varying nutrient 

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concentrations or loading. 

• The springs criteria were established based on the assumption of nitrogen limitation in springs. However, research 

conducted for FDEP on springs throughout Florida indicate that “N:P ratios in the water column and growth assays point 

to indicated phosphorus limitation in many Florida springs.” 

• No mention is made of springs that are subject to back-watering when the receiving water body levels rise, forcing 

water back up the spring run and into the spring boil. This can significantly influence water quality when highly colored 

river water floods a spring boil. Such occurrences can influence the classification of a stream as either clear or colored, 

as most rivers have significantly higher colored water than springs. Since these occurrences may last for an extended 

period of time they can subsequently bias results of sampling in both the spring boil and spring run. 

• In contrast to many of the other criteria, the development of the springs criterion for nitrogen was supported by a doseresponse relationship derived from both laboratory results and field surveys. 

Comment ID 1761-3.001.061 

Author Name: Merrill M. 

Organization: Hillsborough County 

6. Much of the data used to develop the numeric nutrient criteria came from springs within a relatively limited spatial 

extent, i.e., primarily in the north-central region of the state. Given the wide variation across regions in such factors as 

geology, hydrology, and rainfall, no evidence was presented that spring water quality for different systems (e.g., 

Suwannee River, Weeki Wachee, Warm Mineral Springs, Volusia Blue) should respond similarly to varying nutrient 

concentrations or loading. 

Comment ID 1761-3.001.146 

Author Name: Merrill M. 

Organization: Hillsborough County 

III.D. Proposed Numeric Nutrient Criteria for the State of Florida's Springs and Clear Streams 

III.D(1) Proposed Numeric Nutrient Criteria for Springs and Clear Streams 

Comment: 

EPA proposes a target of 0.35 mg/l nitrate-nitrate in springs and clear streams. In addition, the proposed rule states, 

"TN and TP criteria developed for streams on a watershed basis are also applicable to clear streams." The proposed 

rule also states, " EPA has not undertaken the development of TP criteria for springs because phosphorus has 

historically been present in Florida's springs, given the State's naturally phosphorus-rich geology, and the lack of an 

increasing trend of phosphorus concentrations in most spring discharges." These two statements contradict one 

another. For the most part, clear streams in Florida are spring runs. No supporting evidence has been provided in the 

proposed rule or in the TSD to suggest that the piling on of additional numeric limits for TN or TP will improve water 

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Chapter 2 - Comment Documents Springs and Clear Streams 

quality in clear streams. We concur that it is inappropriate and unnecessary to develop a TP criterion for springs. 

The application of the nitrate-nitrite relationship with unhealthy levels of productivity in springs and spring runs may not 

apply to all "clear" streams. Some additional evaluation of the applicability of the criteria outside of springs and spring 

runs needs to be performed prior to the blanket adoption to all clear streams. 

Comment ID 1777-2.001.033 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

6. Much of the data used to develop the numeric nutrient criteria came from springs within a relatively limited spatial 

extent, i.e., primarily in the north-central region of the state. Given the wide variation across regions in such factors as 

geology, hydrology, and rainfall, no evidence was presented that spring water quality for different systems (e.g., 

Suwannee River, Weeki Wachee, Warm Mineral Springs, Volusia Blue) should respond similarly to varying nutrient 

concentrations or loading. 

Comment ID 1777-2.001.117 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

III.D. Proposed Numeric Nutrient Criteria for the State of Florida's Springs and Clear Streams 

III.D(1) Proposed Numeric Nutrient Criteria for Springs and Clear Streams 

Comment: 

EPA proposes a target of 0.35 mg/l nitrate-nitrate in springs and clear streams. In addition, the proposed rule states, 

"TN and TP criteria developed for streams on a watershed basis are also applicable to clear streams." The proposed 

rule also states, " EPA has not undertaken the development of TP criteria for springs because phosphorus has 

historically been present in Florida's springs, given the State's naturally phosphorus-rich geology, and the lack of an 

increasing trend of phosphorus concentrations in most spring discharges." These two statements contradict one 

another. For the most part, clear streams in Florida are spring runs. No supporting evidence has been provided in the 

proposed rule or in the TSD to suggest that the piling on of additional numeric limits for TN or TP will improve water 

quality in clear streams. We concur that it is inappropriate and unnecessary to develop a TP criterion for springs. The 

application of the nitrate-nitrite relationship with unhealthy levels of productivity in springs and spring runs may not apply 

to all "clear" streams. Some additional evaluation of the applicability of the criteria outside of springs and spring runs 

needs to be performed prior to the blanket adoption to all clear streams. 

Comment ID 1805-3.001.046 

Author Name: Gallagher J. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Organization: Pasco County 

6. Much of the data used to develop the numeric nutrient criteria came from springs within a relatively limited spatial 

extent, i.e., primarily in the north-central region of the state. Given the wide variation across regions in such factors as 

geology, hydrology, and rainfall, no evidence was presented that spring water quality for different systems (e.g., 

Suwannee River, Weeki Wachee, Warm Mineral Springs, Volusia Blue) should respond similarly to varying nutrient 

concentrations or loading. 

Comment ID 1805-3.001.132 

Author Name: Gallagher J. 

Organization: Pasco County 

III.D. Proposed Numeric Nutrient Criteria for the State of Florida’s Springs and Clear Streams 

III.D(1) Proposed Numeric Nutrient Criteria for Springs and Clear Streams 

Comment: 

EPA proposes a target of 0.35 mg/l nitrate-nitrate in springs and clear streams. In addition, the proposed rule states, 

“TN and TP criteria developed for streams on a watershed basis are also applicable to clear streams.” The proposed 

rule also states, “ EPA has not undertaken the development of TP criteria for springs because phosphorus has 

historically been present in Florida’s springs, given the State’s naturally phosphorus-rich geology, and the lack of an 

increasing trend of phosphorus concentrations in most spring discharges.” These two statements contradict one 

another. For the most part, clear streams in Florida are spring runs. No supporting evidence has been provided in the 

proposed rule or in the TSD to suggest that the piling on of additional numeric limits for TN or TP will improve water 

quality in clear streams. We concur that it is inappropriate and unnecessary to develop a TP criterion for springs. 

The application of the nitrate-nitrite relationship with unhealthy levels of productivity in springs and spring runs may not 

apply to all “clear” streams. Some additional evaluation of the applicability of the criteria outside of springs and spring 

runs needs to be performed prior to the blanket adoption to all clear streams. 

Comment ID 1885.001.010 

Author Name: Connor T. 

Organization: Office of the Executive Director, Sarasota County 

Springs - The three springs in Sarasota County, Warm Mineral Spring, Little Salt Spring, and Deep Hole, have not been 

extensively studied. Developing appropriate numeric nutrient criteria for these systems would be challenging because of 

they are unlike other springs in Florida. They should not be presumed to be impaired without evidence appropriate to 

their nature . 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1887-1.001.003 

Author Name: Manson D. 

Organization: Manson Law Group, P.A. on behalf of Nestle Water North America 

Conclusions 

Nestle appreciates the opportunity to submit its comments on the EPA proposed numeric nutrient criteria rule . Nestle 

believes the EPA's proposed numeric nutrient criteria rule could be improved by (I) addressing regionalization of springs 

criteria based on climatic and geologic differences, (2) addressing the need to more appropriately link statistically 

significant change points to biological integrity or designated uses and (3) provide greater consideration for 

implementation strategies to ensure criteria are accurately enforced. Nestle encourages the EPA to continue to work 

with the FDEP and the myriad of stakeholders in Florida to develop scientifically defensible numeric nutrient criteria. 

Comment ID 2018-6.001.016 

Author Name: McLean J. 

Organization: City of Tampa 

34. A spring run is defined as a free-flowing water body that receives more that 50% of its flow from a spring. However, 

it is not defined as to whether this determination is based on an instantaneous measurement, annual average, period of 

record average, or other measurement. Much of the data used to develop the numeric nutrient criteria came from 

springs within a relatively limited spatial extent, i.e., primarily in the north-central region of the state. Given the wide 

variation across regions in such factors as geology, hydrology, and rainfall, no evidence was presented that spring 

water quality for different systems (e.g., Suwannee River, Weeki Wachee, Warm Mineral Springs, Volusia Blue) should 

respond similarly to varying nutrient concentrations or loading. The springs criteria were established based on the 

assumption of nitrogen limitation in springs. However, research conducted for FDEP on springs throughout Florida 

indicate that "N:P ratios in the water column and growth assays point to indicated phosphorus limitation in many Florida 

springs." 

35. No mention is made of springs that are subject to back-watering when the receiving water body levels rise, forcing 

water back up the spring run and into the spring boil. This can significantly influence water quality when highly colored 

river water floods a spring boil. Such occurrences can influence the classification of a stream as either clear or colored, 

as most rivers have significantly higher colored water than springs. Since these occurrences may last for an extended 

period of time they can subsequently bias results of sampling in both the spring boil and spring run. In contrast to many 

of the other criteria, the development of the springs criterion for nitrogen was supported by a dose-response relationship 

derived from both laboratory results and field surveys. 

Response 

Comment IDs: 1063.001.005, 1197.001.006, 1352-1.001.132, 1352-1.001.133, 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Response: EPA agrees with comments that re-state and support EPA’s stressor-response based approach for deriving nutrient 

criteria for Florida’s springs as described in the Agency’s proposed rule. 

Comment IDs: 1217-2.001.007, ID 1761-3.001.146, ID 1777-2.001.117, ID 1805-3.001.132 

Response: After careful consideration and an evaluation of comments received regarding this issue, EPA has decided not to finalize 

the springs NO3+NO2 criterion in clear streams. EPA considers the numeric nutrient criteria it is finalizing in this rule for streams, 

including clear streams, to be protective of designated uses and scientifically defensible. EPA concluded that Florida’s streams, 

including clear streams, will also be protected from excessive inorganic nitrogen pollution by the NO3+NO2 criteria, where there 

are springs in the streams’ upstream watershed. 

Comment IDs: 1355-2.001.050, 1761-3.001.061, 1777-2.001.033, 1355-2.001.095, 1805-3.001.046, 1885.001.010, 2018-6.001.016 

Response: EPA disagrees with comments that springs criteria derived using data from certain sites are not applicable across a 

broader region. The NO3+NO2 criteria were derived from multiple lines of evidence, including laboratory studies and analyses of 

field data. While the locations of the field studies used in deriving this criterion were geographically limited and local conditions 

can modulate the relationships between NO3+NO2 and algal abundance, EPA concluded that the laboratory studies, which 

indicated a strong response between NO3+NO2 concentration and algal abundance, are relevant to all springs. EPA found no 

evidence to suggest that a differential response of nuisance algae to NO3+NO2 in Florida’s springs would occur, particularly when 

the same nuisance algae are known to occur across the State. With respect to backwatering, EPA agrees in general with comments 

that backwatering events can potentially influence water quality. However, EPA notes that no additional information or specific 

examples demonstrating the effects of backwatering on water quality in springs was provided by commenters. Assuming the effects 

of backwatering can be demonstrated, site-specific criteria for the spring of interest can be developed and submitted to EPA as an 

application for a federal SSAC. Furthermore, FDEP may be able to provide clarification on the field sampling protocols to specify 

the timing of the collection of water quality samples, which may mitigate the issue of backwatering. 

Comment ID: 1887-1.001.003 

Response: EPA disagrees with the commenter’s first point. Based on EPA’s review of the evidence supporting its springs criteria, 

the source waters for springs are quite similar across the State. Furthermore, while there may be differences in the physical (e.g., 

shading), chemical and ecological conditions from site to site across the State, overall EPA would expect, based on surveys of 

Florida springs that showed certain taxa of nuisance algae occur across the State (see final rule TSD), that the biological response of 

nuisance algae to NO3+NO2 to be generally similar across the State, perhaps modulated by conditions at a particular location. EPA 

disagrees with the commenter’s second point suggesting that change point analysis was not an appropriate analysis to apply to this 

data. The studies that applied change point analysis to the data did so because these model forms (i.e., a step function for the 

response variable) accounted for more variability in the response variables than other methods (Niu 2007). EPA agrees with 

comments that uncertainty in estimated change points should be quantified. This uncertainty was quantified at proposal and 

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Chapter 2 - Comment Documents Springs and Clear Streams 

confidence intervals for changepoints were estimated using bootstrap re-sampling. EPA generally agrees with the commenter’s 

third point regarding the importance of implementation strategies to enforce water quality standards. However, implementation was 

not a consideration for EPA as it developed scientifically defensible numeric nutrient criteria protective of Florida’s designated uses 

in springs. 

III.D.2.A - DERIVATION OF PROPOSED NITRATE-NITRITE 

CRITERIA 

Comment ID 1352-1.001.072 

Author Name: Herr M. 

Organization: Polk County 

Springs and Clear Streams 

• Much of the data used to develop the numeric nutrient criteria came from springs within a relatively limited spatial 

extent, i.e., primarily in the north-central region of the state. Given the wide variation across regions in such factors as 

geology, hydrology, and rainfall, no evidence was presented that spring water quality for different systems (e.g., 

Suwannee River, Weeki Wachee, Warm Mineral Springs, Volusia Blue) should respond similarly to varying nutrient 

concentrations or loading. 

Comment ID 1352-1.001.073 

Author Name: Herr M. 

Organization: Polk County 

Springs and Clear Streams 

• The springs criteria were established based on the assumption of nitrogen limitation in springs. However, research 

conducted for FDEP on springs throughout Florida indicate that "N:P ratios in the water column and growth assays point 

to indicated phosphorus limitation in many Florida springs." 

Comment ID 1761-3.001.157 

Author Name: Merrill M. 

Organization: Hillsborough County 

Springs and Clear Streams (Section III.D) 

1. The nitrate-nitrite criteria as proposed should be applicable primarily to springs and spring runs as the field and 

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Chapter 2 - Comment Documents Springs and Clear Streams 

laboratory work conducted was primarily for this purpose and recognizes the unique nature of springs. 

Comment ID 1805-3.001.041 

Author Name: Gallagher J. 

Organization: Pasco County 

Springs and Clear Streams (Section III.D) 

1. The nitrate-nitrite criteria as proposed should be applicable primarily to springs and spring runs as the field and 

laboratory work conducted was primarily for this purpose and recognizes the unique nature of springs. 

Response 

III.D.2.a Derivation of proposed nitrate-nitrite criteria 

Comment ID: 1352-1.001.072 

Response: EPA disagrees with comments that springs criteria derived using data from certain sites are not applicable across a 

broader region. The NO3+NO2 criteria were derived from multiple lines of evidence, including laboratory studies and analyses of 

field data. While the locations of the field studies used in deriving this criterion were geographically limited and local conditions 

can modulate the relationships between NO3+NO2 and algal abundance EPA concluded that the laboratory studies, which indicated 

a strong response between NO3+NO2 concentration and algal abundance, are relevant to all springs. EPA found no evidence to 

suggest that a differential response of nuisance algae to NO3+NO2 in Florida’s springs would occur, particularly when the same 

nuisance algae are known to occur across the State. 

Comment ID: 1352-1.001.073 

Response: EPA disagrees with the comment that its springs criteria “were established based on the assumption of nitrogen 

limitation”. EPA did not assume nutrient limitation when it derived the NO3+NO2 criteria. However, EPA acknowledges that 

phosphorus may be limiting in a number of Florida springs and that limitation may vary over time and space. It is unclear to EPA 

whether the comment is suggesting that EPA should derive numeric phosphorus criteria for Florida’s springs. While it may be 

informative to consider nutrient limitation in deriving numeric nutrient criteria, EPA’s policy on numeric nutrient criteria does not 

pre-condition criteria development based on the limiting nutrient, nitrogen or phosphorus. 

Comment IDs: 1761-3.001.157, 1805-3.001.041 

Response: After careful consideration and an evaluation of comments received regarding this issue, EPA has decided not to finalize 

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Chapter 2 - Comment Documents Springs and Clear Streams 

the springs NO3+NO2 criterion in clear streams. EPA considers the numeric nutrient criteria it is finalizing in this rule for streams, 

including clear streams, to be protective of designated uses and scientifically defensible. EPA concluded that Florida’s streams, 

including clear streams, will also be protected from excessive inorganic nitrogen pollution by the NO3+NO2 criteria, where there 

are springs in the streams’ upstream watershed. 

III.D.2.B - PROPOSED CRITERIA: DURATION AND FREQUENCY 

Comment ID 1434-1.001.029 

Author Name: Ford C. 

Organization: Highlands Soil and Water Conservation District Board of Supervisors 

T26 

III D Highlands County does not contain waters considered to be either springs or clear streams, however, the same 

frequency and duration for monitoring criteria discussed above for lakes are directly applicable for springs. The HSWCD 

supports in principle the technical expertise of SWFWMD in their comments to EPA regarding the proposed numeric 

nutrient criteria for the State of Florida's Springs and Clear Streams (SWFWMD 2010) 

Comment ID 1481-1.001.030 

Author Name: Ford C. 

Organization: Highlands County Natural Resources Department 

III D Highlands County does not contain waters considered to be either springs or clear streams, however, the same 

frequency and duration for monitoring criteria discussed above for lakes are directly applicable for springs. Highlands 

County supports in principle the technical expertise of SWFWMD in their comments to EPA regarding the proposed 

numeric nutrient criteria for the State of Florida's Springs and Clear Streams (SWFWMD 2010) 

Comment ID 1768-1.001.024 

Author Name: Armingeon N. 

Organization: St. Johns River Keeper 

• Further, measuring compliance with the standard should be based on seasonal medians from samples taken at least 

monthly. 

Comment ID 1836.001.045 

Author Name: Moore D. 

11/19/2010 02:48 PM EST 2-3974
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Organization: Southwest Florida Water Management District 

34. USEPA should clarify the exceedance standards for springs (page 4210, proposed rule). In the discussion of the 

duration and frequency for meeting the proposed criterion, it is not clear whether USEPA is proposing (1) once-in-three 

years or (2) 10% of monthly values as the appropriate maximum frequencies for exceeding the standard (page 4210, 

proposed rule) . 

Response 

Comment IDs: 1434-1.001.029, 1481-1.001.030 

Response: After careful consideration and analysis of all relevant data for springs, EPA is finalizing a springs criterion of 0.35 mg/L 

not to be exceeded as an annual geometric mean not to be exceeded more than once in three years. This duration and frequency is 

the same as that proposed by EPA and it matches the lakes criteria duration and frequency. 

EPA disagrees that compliance with the springs NO3+NO2 criterion should be based on monthly mean values. EPA found in its 

review of springs data and information that nitrate concentrations can be variable from month to month, and this intra-annual 

variability was not necessarily associated with impairment of the designated use. Therefore, to control for intra-annual variability, 

EPA chose to characterize the springs criteria over an annual basis. 

Comment IDs: 1768-1.001.024, 1836.001.045 

Response: EPA does not specify in its final rule detailed compliance monitoring for springs. EPA defers to FDEP in terms of 

implementation, for monitoring and assessment purposes, of EPA's springs criteria of 0.35 mg/L not to be exceeded as an annual 

geometric mean not to be exceeded more than once in three years. 

III.D.2.Q.1 - METHODOLOGY FOR DERIVING EPA’S PROPOSED 

CRITERIA FOR SPRINGS AND CLEAR STREAMS QUESTION 1 

Comment ID 0922-1.001.043 

Author Name: Fred Lee G. 

Organization: G. Fred Lee & Associates 

Page 133 under (b) "Proposed Criteria: Duration and Frequency EPA is proposing a duration and frequency expression 

of an annual geometric mean not to be surpassed more than once in a three-year period to be consistent with the 

expressions of duration and frequency for other water body types (e.g., lakes, streams, canals) for TN and TP and for 

the same reasons EPA selected a three-year period for those waters. Second, EPA proposes that the long-term 

arithmetic average of annual geometric means not exceed the criterion-magnitude concentration. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

As discussed above the annual average of the geometric mean is not a valid approach for implementation of nutrient 

water quality criteria. The time of the year that the criteria are applied should be governed by when the most significant 

excessive aquatic planktonic algae or other excessive growths of aquatic plants occur. The limitation of nutrient loads to 

a waterbody should be related to the nutrients that are primarily responsible for the greatest water quality problems. 

Comment ID 1352-1.001.144 

Author Name: Herr M. 

Organization: Polk County 

Proposed Duration and Frequency Criteria 

EPA proposed a nitrate-nitrite duration and frequency standard of "an annual geometric mean not to be exceeded more 

than once in a three-year period" to be consistent with the expressions of duration and frequency for other water body 

types (e.g., lakes, streams, canals) for TN and TP and for the same reasons EPA selected a three-year period for those 

waters (EPA, 2010a, page 133). Second, EPA proposed that "the long-term arithmetic average of annual geometric 

means not exceed the criterion-magnitude concentration." EPA has determined that this frequency of excursions should 

not result in unacceptable effects on aquatic life as it will allow the springs and clear streams aquatic systems enough 

time to recover from an occasionally elevated year of nutrient loadings. 

EPA also considered, as an alternative, expressing the duration and frequency criterion as a monthly median not to be 

surpassed more than 10% of the time. Stated another way, the median nitrate-nitrite concentration in any given 

calendar month should not be higher than the target value in more than one out of every ten months. It is appropriate to 

express a monthly criterion as a median because the median is less susceptible to outliers than the geometric mean. 

This is particularly important when dealing with small sample sizes. The rationale for this alternative is that field data 

indicate that the response in springs is correlated to monthly exposure at the criterion-magnitude concentration value 

and a 10% frequency of excursions should be a protective allowance given small sample sizes in any given month. 

Comment ID 1482-1.001.008 

Author Name: Hecker J. 

Organization: Conservancy of Southwest Florida 

C Springs, Spring Runs and Clear Streams 

The Conservancy of Southwest Florida believes that the proposed springs and clear streams criteria are scientifically 

sound. The nitrate+nitrite criterion for springs and clear streams being proposed by EPA are based on extensive 

laboratory and field studies spanning over 50 years to determine levels where there were responses of nuisance or 

noxious algae to nutrient concentrations. This is a rationale and robust approach. We would suggest that the Springs / 

Clear Streams criterion could be strengthened with increased duration and frequency of sampling being required over 

what is currently proposed, including a requirement that the minimum sample size must allow for a scientifically sound 

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assessment of stream conditions. Again, we would suggest the use of the arithmetic mean instead of the geometric 

mean. 

Response 

III.D.2.Q.1 Methodology for deriving EPA’s proposed criteria for springs and clear streams question 1. 

Comment IDs: 1352-1.001.144, 1482-1.001.008 

Response: EPA disagrees with the comment that the median or the arithmetic mean is a more appropriate statistic for the criteria 

magnitude than the geometric mean. EPA specified a geometric mean because it represents a better measure of the central tendency 

of a data set that is log-normally distributed, which nutrient data are known to be. The final rule TSD provides examples of how 

EPA's nutrient data are shown to be log-normally distributed. 

Comment ID: 1352-1.001.144 

Response: EPA disagrees that criteria for springs should be temporally-restricted to when excessive algal growth might occur. EPA 

found no evidence to base a temporally-restricted criterion for springs. While EPA found strong scientific evidence for deriving a 

springs criteria for nitrate+nitrite because of the strength of the stressor-response correlations in laboratory and field data sets, EPA 

does not agree that criteria should be limited to only the nutrients that are "primarily responsible for the greatest water quality 

problems". EPA has expressed its basis for dual nitrogen and phosphorus criteria in the final rule TSD. 

Comment ID: 1482-1.001.008 

Response: EPA could not provide a specific response to the comment because the comment is not clear when the commenter states, 

"criterion could be strengthened with increased duration and frequency of sampling". An increased duration could mean a longer 

duration and thus potentially less stringent compared to EPA's proposal. An increased frequency could mean a higher frequency of 

observations and thus potentially more stringent compared to EPA's proposal. 

With regards to requiring minimum sample size, EPA points out that WQS generally, and EPA’s rule specifically, do not specify 

how to monitor to assess whether the WQS is being met. The State of Florida will determine how best to assess its waters against 

EPA’s numeric nutrient criteria. FDEP is the primary agency responsible for implementing CWA programs in the State of Florida. 

As such, FDEP has the primary responsibility in administering applicable CWA programs consistent with the CWA and EPA’s 

implementing regulations. EPA has worked closely with the State to address nutrient pollution problems in Florida. EPA will 

continue to collaborate with FDEP as the State implements EPA's federally-promulgated numeric nutrient criteria. 

Comment: 0922-1.001.043 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Response: After careful consideration and analysis of all relevant data for springs, EPA is finalizing a springs criterion of 0.35 mg/L 

not to be exceeded as an annual geometric mean not to be exceeded more than once in three years. EPA considers the criteria to be 

protective of designated uses at all times. 

EPA disagrees with the comment that waterbodies should be managed based on the limiting nutrient. EPA acknowledges that one 

or both nutrients, nitrogen and phosphorus may be limiting in Florida springs. However, that limitation, if it occurs, may vary over 

time and space relative to one another. Thus, while it may be informative to consider nutrient limitation in deriving numeric 

nutrient criteria, EPA notes that it may be difficult to definitively identify the limiting nutrient at any given time or place in a spring.

 EPA also notes that employing this premise may not necessarily lead to nutrient criteria that are protective of designated uses, 

particularly in a spring system where export to a downstream water of a non-limiting nutrient may occur. This could lead to 

impairment of a downstream waterbody, which could have been prevented if nutrient criteria were not pre-conditioned on the basis 

of observed nutrient limitation. As such, EPA does not pre-condition numeric nutrient criteria development based on the limiting 

nutrient, nitrogen or phosphorus. Furthermore, EPA did not find sufficient scientific evidence to support a numeric phosphorus 

criterion for Florida springs at this time. EPA notes that there was no evidence to suggest that phosphorus concentrations as springs 

are increasing over time, thus EPA considers the NO3+NO2 criteria to be protective of springs (see final rule TSD). 

III.D.2.Q.2 - METHODOLOGY FOR DERIVING EPA’S PROPOSED 

CRITERIA FOR SPRINGS AND CLEAR STREAMS QUESTION 2 

Comment ID 1480-2.001.003 

Author Name: Wong E. 

Organization: City of Northport 

EPA's Nitrate-Nitrite Criterion for Springs is not adequately protective 

• EPA's criterion is based on DEP's draft criterion, but EPA changed expression from monthly value to annual geometric 

mean 

• Not consistent with the timeframes of observed biological effects contained in the studies used to derive criteria 

• Biological impacts could occur for months without exceedances of criteria 

Comment ID 2233-1.001.027 

Author Name: Kovach C. 

Organization: CF Industries 

3.2 Assessment Methodologies Drastically Reduce the Target Concentration 

Selecting the higher threshold is especially important in that EPA's proposed method of assessing attainment results in 

a net effective ambient target that is considerable lower than the criterion. Just as proposed for TN and TP, EPA would 

assess attainment of the NO3-NO2 criterion as an annual geometric mean not to be exceeded more than once in a 

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Chapter 2 - Comment Documents Springs and Clear Streams 

three- year period; in addition, the long term arithmetic average of annual geometric means may not exceed the 

criterion. This approach fails for the same reasons expressed in response to the assessment methodology applied to 

the TN and TP criteria. Assessment is measured in a different scale than that used to derive the criteria and EPA 

provides no explanation as to why it would apply an arithmetic average of geometric means to assess compliance. 

The Florida DEP suggests using a ten percent exceedance frequency, which EPA discusses in the preamble to its 

proposed rule as an alternative EPA has considered and for which the agency is soliciting comments. As the Florida 

DEP notes in its review of EPA's proposed rule, a 10% exceedance frequency would require the maintenance of an 

ambient instream concentration of 0.10 mg/l NO3-NO2 to maintain compliance. Therefore, neither the EPA nor the 

Florida DEP assessment methodologies are supportable. Both result in an effective ambient target concentration well 

below the already conservative 0.35 mg/l NO3-NO2 criterion. 

Response 

Comment IDs: 1480-2.001.003, 2233-1.001.027 

Response: After careful consideration and analysis of all relevant data for springs, EPA is finalizing a springs criterion of 0.35 mg/L 

not to be exceeded as an annual geometric mean not to be exceeded more than once in three years. EPA disagrees that compliance 

with the springs NO3+NO2 criterion should be based on monthly mean values. EPA found in its review of springs data and 

information that nitrate concentrations can be variable from month to month, and this intra-annual variability was not necessarily 

associated with impairment of the designated use. Therefore, to control for intra-annual variability, EPA chose to characterize the 

springs criteria over an annual basis. 

III.D.2.Q.3 - METHODOLOGY FOR DERIVING EPA’S PROPOSED 

CRITERIA FOR SPRINGS AND CLEAR STREAMS QUESTION 3 

Comment ID 0588.001.004 

Author Name: Gallagher J. 

Organization: Pasco County 

EPA's Nitrate-Nitrite Criterion for Springs is not adequately protective 

- EPA's criterion is based on DEP's draft criterion, but EPA changed expression from monthly value to annual geometric 

mean 

- Not consistent with the timeframes of observed biological effects contained in the studies used to derive criteria 

- Biological impacts could occur for months without exceedances of criteria 

Comment ID 1311.001.008 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Author Name: Long A. 

Organization: 

For streams, I believe the proposed criteria is scientifically sound because we need to do something. However, how you 

decide whether it complies should be by multiple samples, not on a monthly average, because in springs it's seasonally 

dependent on rainfall and what crop is being grown. 

Fish and other aquatic wildlife won't survive an average. Rather, they survive every moment. 

Comment ID 1355-2.001.052 

Author Name: Barker V. 

Organization: Brevard County Board of County Commissioners 

Proposed Duration and Frequency Criteria 

EPA proposed a nitrate-nitrite duration and frequency standard of "an annual geometric mean not to be exceeded more 

than once in a three-year period" to be consistent with the expressions of duration and frequency for other water body 

types (e.g., lakes, streams, canals) for TN and TP and for the same reasons EPA selected a three-year period for those 

waters (EPA, 2010a, page 133). Second, EPA proposed that "the long-term arithmetic average of annual geometric 

means not exceed the criterion-magnitude concentration." EPA has determined that this frequency of excursions should 

not result in unacceptable effects on aquatic life as it will allow the springs and clear streams aquatic systems enough 

time to recover from an occasionally elevated year of nutrient loadings. 

EPA also considered, as an alternative, expressing the duration and frequency criterion as a monthly median not to be 

surpassed more than 10% of the time. Stated another way, the median nitrate-nitrite concentration in any given 

calendar month should not be higher than the target value in more than one out of every ten months. It is appropriate to 

express a monthly criterion as a median because the median is less susceptible to outliers than the geometric mean. 

This is particularly important when dealing with small sample sizes. The rationale for this alternative is that field data 

indicate that the response in springs is correlated to monthly exposure at the criterion-magnitude concentration value 

and a 10% frequency of excursions should be a protective allowance given small sample sizes in any given month. 

FDEP considered a duration frequency target based on monthly values. FDEP (2010c) in its response to EPA's 

proposed criteria notes that using an annual time frame means that "Biological impacts could occur for months without 

exceedances of criteria." However, considering the appropriate duration criteria from the stressor-response approach, it 

is unrealistic to expect to see changes in spring water quality on a monthly time scale based on changes in pollutant 

loading rates, in many cases. 

Comment ID 1464-2.001.034 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Author Name: Ettinger A. 

Organization: Mississippi River Collaborative et al. 

Assessment of compliance should be based on data collected at least monthly, and the sampling frequency should be 

stipulated - As U.S. EPA (2010a, p. 4211) pointed out, the 10% excursion frequency approach would mean that "in 

most cases the monthly ‘median' would actually be based on a single sample, given that most springs are only sampled 

monthly at the most." However, this approach basically renders the concept of "median" meaningless, since the median 

is defined as the mid-range sample value, or the numeric value separating the higher half of sample values from the 

lower half. Thus, the median requires more than one sample value. The alternative approach, use of annual geometric 

means, could allow excessive algal mats and other adverse impacts for months without exceedances of criteria. 

The seasonality of certain mat-forming nuisance/noxious algae should instead be accounted for by basing the draft NOx 

criterion on seasonal medians from data collected at least monthly, and more frequently collected data during known 

major periods of Plectonema (Lyngbya) and Vaucheria growth. A minimum annual sample size also should be 

specified. Otherwise, situations could easily arise wherein there were insufficient data to enable sound assessment of 

conditions in these systems. 

Comment ID 1671-3.001.107 

Author Name: Brooks J. 

Organization: Florida Department of Environmental Protection 

Regarding the frequency of exceedance, there is no evidence to suggest that the short-term responses observed under 

controlled lab settings equate to impairment of the designated use in conditions experienced in State waters. In fact, the 

more realistic field surveys demonstrated that excess biomass does not become persistent in clear streams until 

average nitrate exceeds 0.441 mg/L for a three year period. The 0.441 mg/L threshold was adjusted to 0.35 mg/L to 

provide a fully protective criterion with a low likelihood of excess algal growth (at the 95% confidence limit). 

Although FDEP investigated applying the nitrate criterion as a 10% exceedance frequency of the monthly mean, 

analysis demonstrated that such an expression would unnecessarily require maintenance of longterm average nitrate 

conditions well below the established response threshold. For example, given the typical variance in the data, a stream 

with a long-tem annual average nitrate concentration at 0.35 mg/L would be expected to exceed the criterion during 

approximately 50% of the months, well in excess of a 10% exceedance rate. Review of the month to month nitrate 

variability at stream benchmark sites and sites within the Suwannee drainage basis suggests that average 

concentration in a stream would need to be below 0.10 mg/L in order to consistently meet the <10% exceedance 

requirement of 0.35 mg/L. Therefore, FDEP believes that the exceedance frequency should account for actual nutrient 

variability that does not impact the designated use, and supports a three year averaging period for expressing the 

nitrate criterion. It should be noted that the average age of Floridan Aquifer spring water is greater than 20 years, 

suggesting that any management action based on exceeding the criterion during a three year period could still require 

more than 17 additional years to measure environmental results. 

11/19/2010 02:48 PM EST 2-3981
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1761-3.001.148 

Author Name: Merrill M. 

Organization: Hillsborough County 

III.D(2)(b) Proposed Criteria: Duration and Frequency 

Statement: 

The Agency requests comment on these proposed duration and frequency expressions of the springs and clear 

streams numeric nutrient criteria. 

Comment: 

In general, it seems that the time frame utilized to evaluate impairment should depend upon the expected variability of 

the data and the response characteristics of the systems being evaluated. FDEP studies found that the spring response 

time frame is on the order of one month. The twopronged test using annual geometric means and long-term arithmetic 

average of annual geometric means does not reflect the short response time observed in spring systems. The monthly 

median not to exceed more than 10 percent of the time better reflects the response characteristics seen in the springs. 

We do not believe that it is necessary to include a long term average as a test for impairment as long as the monthly 

not-to-exceed test is being met. We suggest, however, that an exceedance of more than 10 percent may still be 

protective of the designated use. 

Comment ID 1761-3.001.149 

Author Name: Merrill M. 

Organization: Hillsborough County 

Statement: 

EPA requests comment on these proposed criteria duration and frequency expressions, and the basis for their 

derivation. 

Comment: 

As stated above, we are generally supportive of utilizing a time frame for assessment that reflects the response 

characteristics of the system being assessed. The work done by FDEP suggests that a monthly median with an 

allowable exceedance is appropriate for springs. We support this shorter term assessment method over long-term 

approaches, but note that an exceedance allowance of greater than 10 percent may still be protective. 

Comment ID 1761-3.001.150 

11/19/2010 02:48 PM EST 2-3982
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Author Name: Merrill M. 

Organization: Hillsborough County 

Statement: 

EPA requests comment on alternative duration and frequency expressions that might be considered protective, 

including (1) a criterion-duration expressed as a monthly average or geometric mean, (2) a criterion- frequency 

expressed as meeting allowable magnitude and duration every year, (3) a criterion-frequency expressed as meeting 

allowable magnitude and duration in more than half the years of a given assessment period, and (4) a criterionfrequency expressed as meeting the allowable magnitude and duration as a long-term average only. 

Comment: 

We support duration and frequency expressions that adequately reflect the response time frame for the type of water 

body being assessed. In the case of springs, response times to elevated nitrate-nitrite are on the order of one month, 

and a monthly average or geometric mean is likely appropriate, although it is not clear why this might be preferred over 

a monthly median. 

Comment ID 1777-2.001.119 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

III.D(2)(b) Proposed Criteria: Duration and Frequency
 

Statement:
 

The Agency requests comment on these proposed duration and frequency expressions of the springs and clear
 

streams numeric nutrient criteria.
 

Comment:
 

In general, it seems that the time frame utilized to evaluate impairment should depend upon the expected variability of
 

the data and the response characteristics of the systems being evaluated. FDEP studies found that the spring response
 

time frame is on the order of one month. The twopronged test using annual geometric means and long-term arithmetic
 

average of annual geometric means does not reflect the short response time observed in spring systems. The monthly
 

median not to exceed more than 10 percent of the time better reflects the response characteristics seen in the springs.
 

We do not believe that it is necessary to include a long term average as a test for impairment as long as the monthly
 

not-to-exceed test is being met. We suggest, however, that an exceedance of more than 10 percent may still be
 

protective of the designated use.
 

Comment ID 1777-2.001.120 

Author Name: Blanchard B. 

11/19/2010 02:48 PM EST 2-3983
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Organization: Florida Department of Transportation 

Statement:
 

EPA requests comment on these proposed criteria duration and frequency expressions, and the basis for their
 

derivation.
 

Comment:
 

As stated above, we are generally supportive of utilizing a time frame for assessment that reflects the response
 

characteristics of the system being assessed. The work done by FDEP suggests that a monthly median with an
 

allowable exceedance is appropriate for springs. We support this shorter term assessment method over long-term
 

approaches, but note that an exceedance allowance of greater than 10 percent may still be protective.
 

Comment ID 1777-2.001.121 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

Statement:
 

EPA requests comment on alternative duration and frequency expressions that might be considered protective,
 

including (1) a criterion-duration expressed as a monthly average or geometric mean, (2) a criterion- frequency
 

expressed as meeting allowable magnitude and duration every year, (3) a criterion-frequency expressed as meeting
 

allowable magnitude and duration in more than half the years of a given assessment period, and (4) a criterion-


frequency expressed as meeting the allowable magnitude and duration as a long-term average only.
 

Comment:
 

We support duration and frequency expressions that adequately reflect the response time frame for the type of water
 

body being assessed. In the case of springs, response times to elevated nitrate-nitrite are on the order of one month,
 

and a monthly average or geometric mean is likely appropriate, although it is not clear why this might be preferred over
 

a monthly median.
 

Comment ID 1794-1.001.044 

Author Name: Taylor W. 

Organization: US Department of the Interior 

The rationale for the springs nitrogen criterion seems reasonable. The duration and frequency criteria, however, have 

the same problems mentioned earlier for streams. The no-more-than-one-in-three-years excursion frequency for an 

annual mean implies a twoyear interval before establishing noncompliance. Again, this is a long time. It appears that 

EPA dismisses the state's monthly median standard. We recommend that EPA adopt monthly or seasonal criteria for 

springs and streams. 

11/19/2010 02:48 PM EST 2-3984
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1805-3.001.134 

Author Name: Gallagher J. 

Organization: Pasco County 

III.D(2)(b) Proposed Criteria: Duration and Frequency 

Statement:
 

The Agency requests comment on these proposed duration and frequency expressions of the springs and clear
 

streams numeric nutrient criteria.
 

Comment:
 

In general, it seems that the time frame utilized to evaluate impairment should depend upon the expected variability of
 

the data and the response characteristics of the systems being evaluated. FDEP studies found that the spring response
 

time frame is on the order of one month. The two-pronged test using annual geometric means and long-term arithmetic
 

average of annual geometric means does not reflect the short response time observed in spring systems. The monthly
 

median not to exceed more than 10 percent of the time better reflects the response characteristics seen in the springs.
 

We do not believe that it is necessary to include a long term average as a test for impairment as long as the monthly
 

not-to-exceed test is being met. We suggest, however, that an exceedance of more than 10 percent may still be
 

protective of the designated use.
 

Comment ID 1805-3.001.135 

Author Name: Gallagher J. 

Organization: Pasco County 

Statement: EPA requests comment on these proposed criteria duration and frequency expressions, and the basis for 

their derivation. 

Comment: As stated above, we are generally supportive of utilizing a time frame for assessment that reflects the 

response characteristics of the system being assessed. The work done by FDEP suggests that a monthly median with 

an allowable exceedance is appropriate for springs. We support this shorter term assessment method over long-term 

approaches, but note that an exceedance allowance of greater than 10 percent may still be protective. 

Comment ID 1805-3.001.136 

Author Name: Gallagher J. 

Organization: Pasco County 

11/19/2010 02:48 PM EST 2-3985
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Statement: EPA requests comment on alternative duration and frequency expressions that might be considered 

protective, including (1) a criterion-duration expressed as a monthly average or geometric mean, (2) a criterionfrequency expressed as meeting allowable magnitude and duration every year, (3) a criterion-frequency expressed as 

meeting allowable magnitude and duration in more than half the years of a given assessment period, and (4) a criterionfrequency expressed as meeting the allowable magnitude and duration as a long-term average only. 

Comment: We support duration and frequency expressions that adequately reflect the response time frame for the type 

of water body being assessed. In the case of springs, response times to elevated nitrate-nitrite are on the order of one 

month, and a monthly average or geometric mean is likely appropriate, although it is not clear why this might be 

preferred over a monthly median. 

Comment ID 1810-1.001.048 

Author Name: Young L. 

Organization: Clean Water Network of Florida 

Further, measuring compliance with the standard should be based on seasonal medians from samples taken at least 

monthly. 

Response 

Comment IDs: 0588.001.004, 1355-2.001.052, 1464-2.001.034, 1761-3.001.148, 1761-3.001.149, 1761-3.001.150, 1777-2.001.119, 

1777-2.001.120, 1777-2.001.121, 1794-1.001.044, 1805-3.001.134, 1805-3.001.135, 1805-3.001.136, 1810-1.001.048, 1671­

3.001.107 

Response: After careful consideration and analysis of all relevant data for springs, EPA is finalizing a springs criterion of 0.35 mg/L 

not to be exceeded as an annual geometric mean not to be exceeded more than once in three years. EPA disagrees that compliance 

with the springs NO3+NO2 criterion should be based on monthly mean values. EPA found in its review of springs data and 

information that nitrate concentrations can be variable from month to month, and this intra-annual variability was not necessarily 

associated with impairment of the designated use. Therefore, to control for intra-annual variability, EPA chose to characterize the 

springs criteria over an annual basis. 

Comment ID: 1311.001.008 

Response: EPA has not specified in its final rule the monitoring requirements for springs. EPA defers to the State with respect to 

water quality monitoring and assessment procedures. 

III.D.2.Q.4 - METHODOLOGY FOR DERIVING EPA’S PROPOSED 

CRITERIA FOR SPRINGS AND CLEAR STREAMS QUESTION 4 

11/19/2010 02:48 PM EST 2-3986
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1352-1.001.185 

Author Name: Herr M. 

Organization: Polk County 

FDEP considered a duration frequency target based on monthly values. FDEP (2010d) in its response to EPA's 

proposed criteria notes that using an annual time frame means that "Biological impacts could occur for months without 

exceedances of criteria." However, considering the appropriate duration criteria from the stressor-response approach, it 

is unrealistic to expect to see changes in spring water quality on a monthly time scale based on changes in pollutant 

loading rates, in many cases. 

Groundwater generally does not vary in quality at the same time scale as surface waters (from hourly to monthly). 

There is a lag time between the infiltration of water-borne pollutants from the land surface to the expression of that 

pollutant in spring discharge. Therefore, a monthly time scale is likely too short a temporal scale to use. Even an annual 

basis for review may be too short, and a rolling multi-year average may be appropriate. This cannot be determined 

without hydrogeologic modeling to determine typical or site-specific travel times of groundwater, as groundwater travel 

times can vary widely between systems. 

Comment ID 1352-1.001.186 

Author Name: Herr M. 

Organization: Polk County 

Also, requiring the long-term average of geometric means to not exceed the criterion is a proper time scale for 

assessment, but is not totally equitable. The "long-term" average for springs with a short period of record can change 

more rapidly than the average for a spring with a long period of record. Thus a much more significant trend could occur 

in a spring with a long period of time without violating the criteria. A five-year rolling average is recommended for 

assessing springs and clear streams. 

Comment ID 1355-2.001.053 

Author Name: Barker V. 

Organization: Brevard County Board of County Commissioners 

Groundwater generally does not vary in quality at the same time scale as surface waters (from hourly to monthly). 

There is a lag time between the infiltration of water-borne pollutants from the land surface to the expression of that 

pollutant in spring discharge. Therefore, a monthly time scale is likely too short a temporal scale to use. Even an annual 

basis for review may be too short, and a rolling multi-year average may be appropriate. This cannot be determined 

without hydrogeologic modeling to determine typical or site-specific travel times of groundwater, as groundwater travel 

times can vary widely between systems. A five-year rolling average is recommended for assessing springs and clear 

11/19/2010 02:48 PM EST 2-3987
 
Chapter 2 - Comment Documents Springs and Clear Streams 

streams. 

Also, requiring the long-term average of geometric means to not exceed the criterion is a proper time scale for 

assessment, but is not totally equitable. The "long-term" average for springs with a short period of record can change 

more rapidly than the average for a spring with a long period of record. Thus, a much more significant trend could occur 

in a spring with a long period of time without violating the criteria. 

Comment ID 1671-3.001.103 

Author Name: Brooks J. 

Organization: Florida Department of Environmental Protection 

L. Comments on Criteria for Springs, Spring Runs, and Clear Streams 

DEP supports EPA's decision to apply the Nitrate-nitrite criterion to clear streams, in addition to springs and spring runs. 

However, after a careful review of the manner by which the nitrate criterion was derived, DEP believes the criterion 

should be expressed as a 3-year arithmetic mean of the annual geometric means, which should not be surpassed 

during a 3-year averaging period. This three year period for expressing the criterion is consistent with the timeframes 

used to derive the criterion. Dr. Xufeng Niu, Florida State University Dept. of Statistics, conducted the change point 

analyses of periphytometer data based upon three year averages. According to Dr. Niu, "Sample averages were used 

in the analysis instead of individual samples for the purpose of reducing random variation and better representing the 

environmental conditions during the given time periods. Sample sizes for each of the 13 stations in the four (3 year) 

time periods ranged from 5 to 20. Annual averages were not used due to small sample sizes (There were no, or only 

one or two observations for some years at some stations)." (Niu 2008) 

The EPA expression of duration and frequency of the criteria contained in footnote a related to the annual geometric 

mean not being surpassed more than once in a three-year period is not consistent with the derivation of the criterion. 

The FDEP recommends the following edit: 

Concentration values are based on the arithmetic average of the annual geometric means calculated for a three year 

period, not to be surpassed in any given three year period. [more than once in a three-year period. In addition, the longterm average of annual geometric mean values shall not surpass the listed concentration values.]Strikethrough. 

(Duration = annual; Frequency = not to be exceeded [more than once]Strikethrough during [in]Strikethrough a threeyear period [or]Strikethrough as a [long-term]Strikethrough three year average). 

The springs and clear streams nitrate criterion was derived based on multiple lines of evidence, with the primary lines of 

evidence being mesocosm dosing experiments and field studies. Although the mesocosm studies revealed response 

time frames shorter than one year, the inability of lab studies to reproduce field conditions (e.g., lack of grazers or other 

physical disturbance) suggests that lab studies should not be relied upon for the duration component of a criterion. The 

three year average periphyton response to nitrate enrichment was among the strongest evidence for the criterion, 

suggesting that the three year averaging period is the most appropriate duration for criterion expression. See FDEP's 

draft Technical Support Document in the EPA docket for more information on the studies underlying the nitrate criterion. 

11/19/2010 02:48 PM EST 2-3988
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1761-3.001.151 

Author Name: Merrill M. 

Organization: Hillsborough County 

Statement: 

EPA further requests comment on whether an expression of the criteria in terms of an arithmetic average of annual 

geometric mean values based on rolling three-year periods of time would also be protective of the designated use. 

Comment: 

Based upon the fact that springs respond to elevated nitrate-nitrite over a relatively short time frame, we do not feel that 

a rolling annual average is the most applicable standard to use. 

Comment ID 1777-2.001.122 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

Statement:
 

EPA further requests comment on whether an expression of the criteria in terms of an arithmetic average of annual
 

geometric mean values based on rolling three-year periods of time would also be protective of the designated use.
 

Comment:
 

Based upon the fact that springs respond to elevated nitrate-nitrite over a relatively short time frame, we do not feel that
 

a rolling annual average is the most applicable standard to use.
 

Comment ID 1805-3.001.137 

Author Name: Gallagher J. 

Organization: Pasco County 

Statement: EPA further requests comment on whether an expression of the criteria in terms of an arithmetic average of 

annual geometric mean values based on rolling three-year periods of time would also be protective of the designated 

use. 

11/19/2010 02:48 PM EST 2-3989
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Comment: Based upon the fact that springs respond to elevated nitrate-nitrite over a relatively short time frame, we do 

not feel that a rolling annual average is the most applicable standard to use. 

Response 

Comment IDs: 1352-1.001.185, 1355-2.001.053 

Response: EPA agrees with comments that groundwater retention times are long and the timescale for water quality management 

actions to take effect is long. EPA recognizes that groundwater sources for springs can reflect historical nutrient enrichment and 

that water quality management actions would be expected to influence nutrient concentrations in springs only on long (e.g., 

decades) time scales. EPA also points out WQS under the Clean Water Act (CWA) are not applicable to groundwater, nor does the 

State consider groundwater a Class I or III water. When groundwater surfaces at a spring vent and travels down the spring run, then 

it becomes a "water of the U.S." covered by the CWA, EPA's determination under CWA section 303(c)(4)(B), and EPA's final rule. 

After careful consideration and analysis of all relevant data for springs, EPA is finalizing a springs criterion of 0.35 mg/L not to be 

exceeded as an annual geometric mean not to be exceeded more than once in three years. Thus, EPA's final criteria for springs is 

consistent with the comments suggesting a longer term (i.e., more than a year) rolling average. 

Comment IDs: 1352-1.001.186, 1761-3.001.151, 1777-2.001.122, 1805-3.001.137 

Response: Insufficient data are always a limitation that will have to be addressed both in the development of criteria and in 

assessment procedures. However, EPA disagrees with the comment that the five-year rolling average is a more appropriate statistic 

than the geometric mean. EPA specified a geometric mean because it represents a better measure of the central tendency of a data 

set that is log-normally distributed, which nutrient data are known to be. The final rule TSD provides examples of how EPA's 

nutrient data are shown to be log-normally distributed. On the issue of duration and frequency, EPA is finalizing spring criteria for 

Nitrate (NO3-)+Nitrite (NO2-) of 0.35 mg/L not to be exceeded as an annual geometric mean not to be exceeded more than once in 

three years. After review of temporal trends in nitrate concentration in a variety of Florida springs, EPA concluded that three years 

of data are sufficient to distinguish the water quality conditions with respect to nitrate+nitrite and five years of data does not provide 

added confidence in characterizing the water quality conditions. 

Comment ID: 1671-3.001.103 

Response: After careful consideration and analysis of all relevant data for springs, EPA is finalizing a springs criterion of 0.35 mg/L 

not to be exceeded as an annual geometric mean not to be exceeded more than once in three years. This is similar to the duration 

and frequency suggested by the commenter. However, EPA specified a geometric mean because it represents a better measure of 

the central tendency of a data set that is log-normally distributed, which nutrient data are known to be. The final rule TSD provides 

examples of how EPA's nutrient data are shown to be log-normally distributed. 

III.D.3 - REQUEST FOR COMMENT AND DATA ON PROPOSED 

11/19/2010 02:48 PM EST 2-3990
 
Chapter 2 - Comment Documents Springs and Clear Streams 

APPROACH 

No Comments are Applicable to this Issue Category, and Thus No Response is Necessary. 

III.D.3.Q.1 - REQUEST FOR COMMENT AND DATA ON PROPOSED 

APPROACH QUESTION 1 

Comment ID 0695.001.002 

Author Name: Grane C. 

Organization: Marion County Water Conservation District 

And I don't want to see the EPA come in here and regulate in a way that is not appropriate to the specific conditions. 

When I hear you say .35 for nitrogen in springs, you cannot expect the same standard in a spring that is completely 

surrounded by state forest, and another one that is in downtown city. It's just not going to work. You know, I would love 

to see springs clear. I've been here for 40 years. I've watched them go from crystalline to absolutely contaminated in 

many cases, but in many cases we don't even know where it's coming from. We need the resources to do the kind of 

work that says this nitrogen is coming from that source, and that nitrogen is coming from that source, and it's ten 

percent ag, and it's 90 percent the treatment facility. Please don't regulate -- and I don't want to see -- that's not my 

point. It breaks my heart to see the shape it's in, but let's not get it wrong. 

11/19/2010 02:48 PM EST 2-3991
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 0915-1.001.010 

Author Name: Stephens G. 

Organization: The Niceville-Valparaiso-Okaloosa County Regional Sewer Board, Inc.

 8. NVOC has 10 years' data on the spring where the stream which bisects their sprayfield originates upgradient of the 

sprayfield. The water emanating from this spring does not meet the proposed nitrate and nitrite limit proposed by EPA. 

The land upgradient of the sprayfield is virgin timberland for miles. 

Comment ID 1217-2.001.017 

Author Name: Voyles J. 

Organization: Mosaic Fertilizer LLC 

3. Mosaic Comments on Clear Streams and Spring Runs 

EPA's process for developing nitrate criteria for springs and spring runs appears scientifically grounded and robust. 

From both field and laboratory investigations, there appears to be a strong relationship in springs between nitrate 

concentrations and the growth and abundance of certain periphyton algal species. The value derived by EPA (0.35 

mg/L) appears to be reasonably well supported for use in the springs and spring runs where it was derived.[42] 

However, application of this same 0.35 mg/L criterion to clear streams is not justified. Clear streams do not have 

physical or chemical characteristics similar to springs. According to FDEP data, most of the nearly 225 stream WBIDs in 

Florida that are below the color threshold for "clear" streams are not associated with springs. Florida springs and spring 

runs possess a consistent set of ecological characteristics, including relatively constant temperature, high water clarity, 

limestone-dominated geology, and appreciable water velocities. Clear streams generally lack these characteristics. 

According to the Florida Impaired Waters Rule ("IWR") data collected from 2000 to 2008, springs average one-third 

more calcium and four-times more nitrate than clear streams. In addition, springs have half the color, dissolved oxygen, 

and salinity that clear streams have. One of the most important differences between the two waterbody types is that 

temperatures in springs show less than half the variation of clear streams. Accordingly, EPA cannot assume that the 

nitrate criterion derived from analysis of springs and spring runs automatically transfers to non-spring streams that have 

very different temperature, chemical, clarity and velocity conditions. 

[42] Mosaic notes that this value was primarily derived from work conducted from a limited number of spring systems in 

a relatively small portion of the State, leaving some question regarding the applicability of the same single criterion 

value in dozens to hundreds of springs located throughout the rest of the State. Mosaic suggests that further study may 

point to the need for different criteria (potentially in the form of SSACs) for other springs in other parts of the State. 

Comment ID 1217-2.001.046 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Author Name: Voyles J. 

Organization: Mosaic Fertilizer LLC 

Solution: Modify Nitrate Criteria to Apply Only to Springs and Spring Runs 

Mosaic proposes that EPA restrict the 0.35 mg/L nitrate criterion to springs and spring runs, while clear streams would 

be governed by the same criteria that apply to all other streams.[46] We recommend the pertinent Section of the Rule 

be amended as follows: 

[131.43(b)(2). Clear Stream means a free-flowing water whose color is less than 40 platinum cobalt units 

(PCU).]Strikethrough 

131.43(c)(3). Criteria for springs, and spring runs, [and clear streams]Strikethrough. The applicable nitrate-nitrite 

criterion is 0.35 mg/L as an annual geometric mean not to be surpassed more than once in a three year period, nor 

surpassed as a long-term average of annual geometric mean values. [In addition to this nitrate-nitrite criterion, criteria 

identified in paragraph (c)(2) of this section are applicable to clear streams.]Strikethrough 

[46] Mosaic has elsewhere provided detailed comments and revisions concerning the IPVs proposed by EPA. The 

proposed revisions, if incorporated into the Rule, would allow for adequate protection of Florida's streams and rivers, 

including clear streams. 

Comment ID 1230.001.007 

Author Name: Craw V. 

Organization: Southwest Florida Water Management District 

The E.P.A. approach of using the single nitrate/nitrite criterion of 0.35 milligrams per liter for all springs and clear 

streams is inappropriate. E.P.A. should instead develop system-specific nitrate/nitrite targets. 

Comment ID 1304-1.001.030 

Author Name: Stewart J. 

Organization: Florida Pulp and Paper Association Environmental Affairs, Inc. 

3. Change Point Analysis 

The results of a statistical examination of data, such as those presented by EPA for Florida's springs and spring runs, 

may indicate that there exist a statistically significant threshold, or change-point, in this case the response of periphyton 

to nitrate concentrations. However, the Agency fails to address or recognize that the laboratory or field studies link this 

change-point to designated use. The appropriateness of using a change-point analysis to establish standards done in 

11/19/2010 02:48 PM EST 2-3993
 
 

Chapter 2 - Comment Documents Springs and Clear Streams 

the absence of determining the causal relationship or biological significance and even if statistically significant 

correlations or change-points have been found is flawed andarbitrary. The report by Entrix on this is summarized in the 

comments below. (Entrix at Section 3) 

• The change-point analysis method used by EPA to set springs and clear streams criteria could be improved by using 

multiple biological response variables and multiple statistical methods to confirm the ecological significance of a 

statistical change-point before the results of the analyses are used to set numeric water quality criteria. Different 

statistical methods of change-point analysis may give different threshold values, so several methods should be 

explored. 

• Change-point analysis is more likely to find a statistically significant threshold near the center of a dataset, regardless 

of the biological response that is indicative of a desired designated use. A dataset may also have multiple change 

points, but in these analyses EPA only identified the first change-point of each distribution. Multiple change-points could 

be present, with a statistically stronger change-point potentially masking a more biologically significant change-point. 

• EPA should report more information about the change-point analyses used to set the nitrate criteria, including 

information on the method and program used the goodness-of-fit and uncertainty measures associated with the tests, 

and any alternative change-points that may be present. 

• The spring and spring run criteria could be improved by allowing for flexibility in nutrient concentrations if a proscribed 

biological response level has been met, as was done for the lake modified criteria. 

• The 0.35 mg/L nitrate criteria is not appropriate for clear streams, given the many differences in geological and 

ecological characteristics between them. In addition, the data for clear streams does not indicate a potential changepoint in biological response around 0.3 - 0.5 mg/L, as was seen in EPA's spring studies. Instead, the most likely 

statistical threshold for clear streams falls around 1.0 mg/L nitrate. We recommend that EPA restrict the application of a 

nitrate criterion to springs and spring runs. For clear streams, EPA should conduct additional studies and analysis to 

establish a higher nitrate criterion for clear streams that is closer to a biologically significant change point in those 

systems. 

Comment ID 1311.001.009 

Author Name: Long A. 

Organization: 

Springs have sustained serious damage in Florida as a result of nitrogen pollution. The proposed nitrogen criteria for 

springs and spring runs and clear streams should be revised based upon evidence I have seen at BMAP DEP meetings 

that's actually less than what you are proposing, and that is 23 micrograms per liter. And I will supply all my data to you 

in writing that supports what I say so you can have the geologic information. Thank you very much. 

Comment ID 1346-1.001.010 

11/19/2010 02:48 PM EST 2-3994
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Author Name: Still D. 

Organization: Suwannee River Water Management District 

4. Similarly, the nitrate criterion in springs was developed using evidence that as nitrate concentration increases, so 

does the growth of nuisance algae. While this relationship and the need for reducing nitrate impacts to springs is not 

disputed, there has been no meaningful demonstration that reducing nitrates in an impaired spring will reduce nuisance 

algae. However, the public and other affected parties will have this expectation. Systems not considered impaired under 

the nitrate standard also have been observed with nuisance algae. EPA should consider that the reduction of nuisance 

algae is assumed but not assured, and that development of success criteria based on more than a single biological 

response is in the best interest of the public. 

Comment ID 1352-1.001.074 

Author Name: Herr M. 

Organization: Polk County 

Springs and Clear Streams 

• No mention is made of springs that are subject to back-watering when the receiving water body levels rise, forcing 

water back up the spring run and into the spring boil. This can significantly influence water quality when highly colored 

river water floods a spring boil. Such occurrences can influence the classification of a stream as either clear or colored, 

as most rivers have significantly higher colored water than springs. Since these occurrences may last for an extended 

period of time they can subsequently bias results of sampling in both the spring boil and spring run. 

Comment ID 1352-1.001.075 

Author Name: Herr M. 

Organization: Polk County 

Springs and Clear Streams 

• In contrast to many of the other criteria, the development of the springs criterion for nitrogen was supported by a doseresponse relationship derived from both laboratory results and field surveys. 

Comment ID 1352-1.001.128 

Author Name: Herr M. 

Organization: Polk County 

11/19/2010 02:48 PM EST 2-3995
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Summary of Proposed Numeric Nutrient Criteria for Springs and Clear Streams 

Historically, springs nitrate concentrations of 0.05 mg/L or less have been documented, which is low enough to prevent 

excess algae growth (Katz et al., 1999). Nitrate concentrations of 0.5 - 1.0 mg/L or more are now commonly observed 

(Scott et al., 2004). EPA (2010a, page 127; 2010b, page 3-2) cites numerous studies and field investigations 

documenting increases in spring nitrate-nitrite content of 10 to 350 percent over the past 50 years. 

Comment ID 1352-1.001.129 

Author Name: Herr M. 

Organization: Polk County 

Summary of Proposed Numeric Nutrient Criteria for Springs and Clear Streams 

Laboratory testing has shown that keeping nitrogen levels below critical concentrations inhibits the growth of nuisance 

vegetation such as the algae Lyngbya wollei, Vaucheria sp., and periphyton. Therefore, controlling and reducing nitratenitrite is important to maintaining and improving spring systems in Florida. There are several reasons why controlling 

nitrate-nitrite in particular is important to protect springs (EPA, 2010b, page 3-5): 

• Increases in nitrate-nitrite concentrations in springs are nearly universal in areas where anthropogenic nutrient loading 

to the land's surface has occurred. There are no geological sources of nitrogen, therefore all nitrogen observed in 

groundwater derives from land-based inputs. 

• Once in the groundwater, denitrification is negligible and nitrate-nitrite appears to be transported as a conservative 

substance. 

• It is well documented that algae growth is strongly correlated with increasing nitrogen concentrations in the water. 

• Although Florida's geology is naturally rich in phosphorus, there does not appear to be a trend of increasing 

phosphorus concentrations in spring discharges. While nitrate-nitrite concentrations have increased significantly in most 

spring discharges, phosphorus concentrations have remained relatively constant over the past 50 years. 

• Because springs are naturally rich in phosphorus, the majority of Florida springs are likely to have been historically 

nitrogen-limited (Brown et al., 2008). 

Using only nitrite-nitrate to manage springs may not be sufficient in some cases. Although background phosphorus 

levels are high in some areas such as the Bone Valley formation, this is not a state-wide phenomenon. Stevenson et al. 

(2007) states that "N:P ratios in the water column and growth assays indicated that phosphorus is the most limiting 

nutrient in many Florida Springs." 

Comment ID 1352-1.001.130 

Author Name: Herr M. 

Organization: Polk County 

11/19/2010 02:48 PM EST 2-3996
 
 

Chapter 2 - Comment Documents Springs and Clear Streams 

Summary of Proposed Numeric Nutrient Criteria for Springs and Clear Streams 

Also, results from the Stevenson et al. (2007) survey of 60 springs in Florida failed to show any correlation between the 

abundance of Lyngbya wollei, a common microalgae in Florida springs, and water column nutrient concentrations. 

Other factors may also affect growth rates of nuisance algae including current, water clarity, and sediment chemistry. 

Abundance of Lyngbya wollei was correlated with the level of anthropogenic disturbance near the springs, as measured 

by the Landscape Development Intensity Index (LDI). This suggests that factors such as runoff turbidity entering the 

spring could have significant impacts. 

Comment ID 1352-1.001.131 

Author Name: Herr M. 

Organization: Polk County 

Methodology 

EPA's proposed nitrate-nitrite criteria for springs and clear streams are derived from a combination of an analysis of 

FDEP laboratory data, field surveys, and analyses to determine the stressor response-based thresholds that link nitratenitrite levels to biological risk in springs and clear streams. These data document the response of nuisance algae, 

Lyngbya wollei and Vaucheria sp., and periphyton to nitrate-nitrite concentrations (EPA, 2010a, page 130). 

Comment ID 1352-1.001.134 

Author Name: Herr M. 

Organization: Polk County 

Methodology 

EPA reviewed FDEP's data, assumptions, and approach to setting nitrate-nitrite limits and deemed them scientifically 

sound. The FDEP approach included evaluating results from laboratory scale dosing studies, data from in-situ algal 

monitoring, surveys of biological communities and nutrient levels in Florida springs, and data on nitrate-nitrite 

concentrations found in minimally-impacted reference locations (EPA, 2010a, page 3-6). FDEP analyzed laboratory 

data evaluating the response of nuisance algae to increased nitrate. FDEP's analysis showed that Lyngbya wollei and 

Vaucheria sp. reached 90% of their maximum growth at 0.230 mg/L and 0.261 mg/L nitrate-nitrite, respectively 

(Stevenson et al., 2007; Cowell and Dawes, 2004). FDEP also reviewed long-term field surveys that examined the 

response of nuisance algae, periphyton, and eutrophic indicator diatoms to nitrate-nitrite concentration. The results 

showed a sharp increase in abundance and/or biomass of the nuisance algae, periphyton, and diatoms at 0.44 mg/L 

nitrate-nitrite (Gao, 2008). Both laboratory results and field surveys suggest that algae species respond well to 

increased nitrate levels. This strong dose-response data provide evidence that setting the criteria for nitrate is an 

appropriate measure. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1352-1.001.135 

Author Name: Herr M. 

Organization: Polk County 

Methodology 

FDEP also reviewed the field surveys used to develop TMDLs for Wekiva River and Rock Spring Run to evaluate the 

relationship between observed excessive algal growth and imbalance in aquatic vegetation with nutrient concentrations 

in these systems. FDEP found that plant species indicative of eutrophic conditions increased significantly with 

increasing nitratenitrite concentrations above approximately 0.35 mg/L (Mattson et al, 2006). 

Comment ID 1352-1.001.136 

Author Name: Herr M. 

Organization: Polk County 

Methodology 

Setting concentration in springs is an appropriate management tool, but the land area that influences spring water 

quality often extends far beyond the vertical boundaries of surface water drainage areas, the WBIDs. To effectively 

control spring water quality, inputs to groundwater over a large area must be managed. Groundwater pollution 

originates from many sources that cannot easily be traced from a discharge point. 

Comment ID 1352-1.001.137 

Author Name: Herr M. 

Organization: Polk County 

Methodology 

Analogous to the need to consider pollutant loadings in upstream WBIDs in surface water systems, it is necessary to 

manage point and nonpoint source land-based loadings throughout the entire springshed to control water quality in 

spring discharge. Although the limits of the land area contributing to spring discharges can often be relatively well 

delineated, the identification of significant pollutant sources is more difficult, especially in areas with diverse land use 

assemblages. 

Comment ID 1352-1.001.138 

Author Name: Herr M. 

11/19/2010 02:48 PM EST 2-3998
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Organization: Polk County 

Methodology 

Also, the response of surface receiving waters to pollutant loading is relatively rapid. The variability in travel time of 

groundwater from pollutant loading locations to the springs (up to years) means that it may not be feasible to limit 

pollutant loading to groundwater and expect that load reduction to be manifested in spring discharge in the immediate 

future. 

Comment ID 1352-1.001.139 

Author Name: Herr M. 

Organization: Polk County 

Data Used to Develop the Criteria 

Much of the water quality and spring vegetation information used to develop the spring NNC criteria was obtained from 

sites in the northern part of the state, and the data used in the final analysis to develop the proposed criteria were all 

from the Suwannee River system. Although spring distribution is higher to the north, there are significant geological, 

climatic, and biological differences between the northern and central/southern portions of the state. A number of factors 

influence ground-water chemistry. These include the precipitation chemistry, surface conditions at the site of recharge, 

soil type in the recharge area, mineralogy and composition of the aquifer system, nature of aquifer system porosity and 

structure, flow path in the aquifer, residence time of the water in the aquifer, mixing of other waters in the aquifer 

system, and aquifer microbiology (Scott et al, 2004). The proposed rule and TSD present no documentation supporting 

the assumption that Suwannee River system spring data is representative of springs in different parts of the state, (e.g., 

Suwannee River, Weeki Wachee, Volusia Blue, and Warm Mineral Springs). 

Comment ID 1352-1.001.140 

Author Name: Herr M. 

Organization: Polk County 

Data Used to Develop the Criteria 

Regional variability in spring water quality and response of vegetation should be reflected in the criteria. Regional 

differences in water quality are recognized in EPA's proposed stream and lake standards, and a similar analysis is 

warranted for springs, given the wide variation in statewide conditions, especially between the Panhandle and 

Peninsula regions. 

Comment ID 1352-1.001.141 

11/19/2010 02:48 PM EST 2-3999
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Author Name: Herr M. 

Organization: Polk County 

Data Used to Develop the Criteria 

Much of the research used to develop the nitrate-nitrite standards was conducted during a fiveyear period, with longterm data included in the analyses. Data from several sources were used in the analysis, including laboratory bench 

testing to corroborate field survey results and analyses of long-term water quality data. The periphyton and nitrate data 

set used in one of the corroborative tests extended from 1990 and 2007. 

Comment ID 1352-1.001.142 

Author Name: Herr M. 

Organization: Polk County 

Data Used to Develop the Criteria 

FDEP concluded that significant alterations in community composition, in combination with an increase in periphyton 

density and biomass, demonstrate that a nitrate-nitrite level in the range between 0.23 mg/L (the laboratory threshold of 

increased algae growth) and 0.44 mg/L (the field study value associated with substantial observed biological changes) 

is the amount of nitratenitrite associated with an imbalance of aquatic vegetation in spring systems (EPA, 2010a, page 

132). Based on these results and additional analyses, FDEP arrived at a threshold concentration of 0.35 mg/L as 

protective of spring systems, which is now EPA's proposed criterion. 

However, as stated above, results from a field survey of 60 springs in Florida failed to show any correlation between the 

abundance of Lyngbya wollei, a common microalgae in Florida springs, and water column nutrient concentrations. 

Abundance and growth of Vaucheria algae was correlated to nitrate concentrations, showing a "clear threshold" in 

response when nitrate concentrations exceeded 0.454 mg/L, well above the proposed value. 

FDEP noted that a nitrate-nitrite standard of 0.286 ug/L would be conservative, with an implicit margin of safety (MOS). 

Data points for representative spring systems were plotted with potential upper (0.44 ug/L) and lower (0.23 ug/L) 

protective limits. By visual inspection of graphs (EPA, 2010b - Figures 3-7 and 3-8), a change point anywhere between 

the FDEP and EPA values could be determined to be reasonable. A potential alternative could be to select the average 

of the high and low limits as the protective value: 0.335 ug/L, as referenced in Figure 3-10 (EPA, 2010b). 

Comment ID 1352-1.001.143 

Author Name: Herr M. 

Organization: Polk County 

11/19/2010 02:48 PM EST 2-4000
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Data Used to Develop the Criteria 

No mention is made of springs that are subject to back-watering when the receiving water body levels rise, forcing 

water back up the spring run and into the spring boil. This can influence the determination of a stream as clear of 

colored, as most rivers have significantly higher colored water than springs. These effects may last for an extended 

period of time and subsequently bias results of sampling in both the spring boil and spring run. 

Comment ID 1352-1.001.145 

Author Name: Herr M. 

Organization: Polk County 

Proposed Duration and Frequency Criteria 

The nitrate-nitrite criteria as proposed should be applicable primarily to springs and spring runs as the field and 

laboratory work conducted was primarily for this purpose and recognizes the unique nature of springs. Clear streams 

that are not spring fed should not be included. 

Comment ID 1355-2.001.009 

Author Name: Barker V. 

Organization: Brevard County Board of County Commissioners 

Springs and Clear Streams 

Background 

Florida's springs and spring runs (clear springs) are valuable for biological, recreational, economical, and aesthetic 

purposes. Under natural conditions their diverse biota is a function of naturally high water clarity. Two factors have been 

identified as major contributors to observed decreases in spring water quality: pollutant loading to groundwater, 

especially nitrate-nitrite nitrogen, and reduction in spring flow caused by groundwater withdrawals (EPA, 2010, page 

126). Pollutant loadings result in a higher flux of nutrients into the spring, and reduced flows result in increased 

residence time of water in the ground and spring. 

A significant outcome of these factors is that algae and invasive plant species replace desirable native submerged 

aquatic vegetation (SAV). Excessive algae growth may include both floating mats that shade the water and reduce light 

penetration, and periphyton growth on the hard surfaces, smothering native plants (EPA, 2010b, page 3-2). 

Summary of Proposed Numeric Nutrient Criteria for Springs and Clear Streams 

Historically, springs nitrate concentrations of 0.05 mg/L or less have been documented, which is low enough to prevent 

11/19/2010 02:48 PM EST 2-4001
 
Chapter 2 - Comment Documents Springs and Clear Streams 

excess algae growth (Katz et al., 1999). Nitrate concentrations of 0.5 - 1.0 mg/L or more are now commonly observed 

(Scott et al., 2004). EPA (2010a, page 127; 2010b, page 3-2) cites numerous studies and field investigations 

documenting increases in spring nitrate-nitrite content of 10 to 350 percent over the past 50 years. 

Laboratory testing has shown that keeping nitrogen levels below critical concentrations inhibits the growth of nuisance 

vegetation such as the algae Lyngbya wollei, Vaucheria sp., and other periphyton. Therefore, controlling and reducing 

nitrate-nitrite is important to maintaining and improving spring systems in Florida. There are several reasons why 

controlling nitrate-nitrite in particular is important to protect springs (EPA, 2010b, page 3-5): 

• Increases in nitrate-nitrite concentrations in springs are nearly universal in areas where anthropogenic nutrient loading 

to the land's surface has occurred. There are no geological sources of nitrogen, therefore all nitrogen observed in 

groundwater derives from land-based inputs. 

• Once in the groundwater, denitrification is negligible and nitrate-nitrite appears to be transported as a conservative 

substance. 

• It is well documented that algae growth is strongly correlated with increasing nitrogen concentrations in the water. 

• Although Florida's geology is naturally rich in phosphorus, there does not appear to be a trend of increasing 

phosphorus concentrations in spring discharges. While nitrate-nitrite concentrations have increased significantly in most 

spring discharges, phosphorus concentrations have remained relatively constant over the past 50 years. 

• Because springs are naturally rich in phosphorus, the majority of Florida springs are likely to have been historically 

nitrogen-limited (Brown et al., 2008). 

Comment ID 1355-2.001.047 

Author Name: Barker V. 

Organization: Brevard County Board of County Commissioners 

Using only nitrite-nitrate to manage springs may not be sufficient in some cases. Although background phosphorus 

levels are high in some areas such as the Bone Valley formation, this is not ma state-wide phenomenon. Stevenson et 

al. (2007) states that "N:P ratios in the water column and growth assays indicated that phosphorus is the most limiting 

nutrient in many Florida Springs." 

Comment ID 1355-2.001.048 

Author Name: Barker V. 

Organization: Brevard County Board of County Commissioners 

Also, results from the Stevenson et al. (2007) survey of 60 springs in Florida failed to show any correlation between the 

abundance of Lyngbya wollei, a common microalgae in Florida springs, and water column nutrient concentrations. 

Other factors may also affect growth rates of nuisance algae including current, water clarity, and sediment chemistry. 

Abundance of Lyngbya wollei was correlated with the level of anthropogenic disturbance near the springs, as measured 

by the Landscape Development Intensity Index (LDI). This suggests that factors such as runoff turbidity entering the 

11/19/2010 02:48 PM EST 2-4002
 
Chapter 2 - Comment Documents Springs and Clear Streams 

spring could have significant impacts. 

Comment ID 1355-2.001.049 

Author Name: Barker V. 

Organization: Brevard County Board of County Commissioners 

Methodology 

EPA's proposed nitrate-nitrite criteria for springs and clear streams are derived from a combination of an analysis of
 

FDEP laboratory data, field surveys, and analyses to determine the stressor response-based thresholds that link nitrate-


nitrite levels to biological risk in springs and clear streams. These data document the response of nuisance algae,
 

Lyngbya wollei and Vaucheria sp., and periphyton to nitrate-nitrite concentrations (EPA, 2010a, page 130).
 

EPA is not proposing total phosphorus (TP) criteria for springs because phosphorus has historically been present in
 

Florida's springs, given the State's naturally phosphorus-rich geology and the documented lack of an increasing trend of
 

phosphorus concentrations in most spring discharges. Also, EPA is not proposing chlorophyll a or water clarity criteria
 

due to the lack of available data for these response variables in spring systems (EPA, 2010a, page 130).
 

Further, scientific evidence shows a strong relationship between the thickness of periphyton algal biomass attached to
 

substrate and nutrients in clear streams (those with color <40 PtCo units and canopy cover 40% which are comparable
 

to most waters found in springs and spring runs) (Stevenson et al., 2007). Benthic algal thickness has been shown to
 

be highly dependent on nitrogen parameters (TN and total inorganic nitrogen), as opposed to phosphorus. EPA is
 

therefore proposing to apply the nitrate-nitrite criteria derived for springs to clear streams as a measure to gauge
 

anthropogenic contributions to TN (EPA, 2010a, page 131).
 

EPA reviewed FDEP's data, assumptions, and approach to setting nitrate-nitrite limits and deemed them scientifically
 

sound. The FDEP approach included evaluating results from laboratory scale dosing studies, data from in-situ algal
 

monitoring, surveys of biological communities and nutrient levels in Florida springs, and data on nitrate-nitrite
 

concentrations found in minimally-impacted reference locations (EPA, 2010b, page 3-6).
 

FDEP analyzed laboratory data evaluating the response of nuisance algae to increased nitrate.
 

FDEP's analysis showed that Lyngbya wollei and Vaucheria sp. reached 90% of their maximum growth at 0.230 mg/L
 

and 0.261 mg/L nitrate-nitrite, respectively (Stevenson et al., 2007; Cowell and Dawes, 2004). FDEP also reviewed
 

long-term field surveys that examined the response of nuisance algae, periphyton, and eutrophic indicator diatoms to
 

nitrate-nitrite concentration. The results showed a sharp increase in abundance and/or biomass of the nuisance algae,
 

periphyton, and diatoms at 0.44 mg/L nitrate-nitrite (Gao, 2008).
 

Both laboratory results and field surveys suggest that algae species respond well to increased nitrate levels. This strong
 

dose-response data provide evidence that setting the criteria for nitrate is an appropriate measure.
 

FDEP also reviewed the field surveys used to develop TMDLs for Wekiva River and Rock Spring Run to evaluate the
 

relationship between observed excessive algal growth and imbalance in aquatic vegetation with nutrient concentrations
 

11/19/2010 02:48 PM EST 2-4003
 
Chapter 2 - Comment Documents Springs and Clear Streams 

in these systems. FDEP found that plant species indicative of eutrophic conditions increased significantly with 

increasing nitrate-nitrite concentrations above approximately 0.35 mg/L (Mattson et al, 2006). 

Setting concentration in springs is an appropriate management tool, but the land area that influences spring water 

quality often extends far beyond the vertical boundaries of surface water drainage areas, the WBIDs. To effectively 

control spring water quality, inputs to groundwater over a large area must be managed. Groundwater pollution 

originates from many sources that cannot easily be traced from a discharge point. 

Analogous to the need to consider pollutant loadings in upstream WBIDs in surface water systems, it is necessary to 

manage point and nonpoint source land-based loadings throughout the entire springshed to control water quality in 

spring discharge. Although the limits of the land area contributing to spring discharges can often be relatively well 

delineated, the identification of significant pollutant sources is more difficult, especially in areas with diverse land use 

assemblages. 

Also, the response of surface receiving waters to pollutant loading is relatively rapid. The variability in travel time of 

groundwater from pollutant loading locations to the springs (up to years) means that it may not be feasible to limit 

pollutant loading to groundwater and expect that load reduction to be manifested in spring discharge in the immediate 

future. 

Comment ID 1355-2.001.051 

Author Name: Barker V. 

Organization: Brevard County Board of County Commissioners 

Much of the research used to develop the nitrate-nitrite standards was conducted during a five-year period, with longterm data included in the analyses. Data from several sources were used in the analysis, including laboratory bench 

testing to corroborate field survey results and analyses of long-term water quality data. The periphyton and nitrate data 

set used in one of the corroborative tests extended from 1990 and 2007. 

FDEP concluded that significant alterations in community composition, in combination with an increase in periphyton 

density and biomass, demonstrate that a nitrate-nitrite level in the range between 0.23 mg/L (the laboratory threshold of 

increased algae growth) and 0.44 mg/L (the field study value associated with substantial observed biological changes) 

is the amount of nitrate-nitrite associated with an imbalance of aquatic vegetation in spring systems (EPA, 2010a, page 

132). Based on these results and additional analyses, FDEP arrived at a threshold concentration of 0.35 mg/L as 

protective of spring systems, which is now EPA's proposed criterion. 

However, as stated above, results from a field survey of 60 springs in Florida failed to show any correlation between the 

abundance of Lyngbya wollei, a common microalgae in Florida springs, and water column nutrient concentrations. 

Abundance and growth of Vaucheria algae was correlated to nitrate concentrations, showing a "clear threshold" in 

response when nitrate concentrations exceeded 0.454 mg/L, well above the proposed value. 

FDEP noted that a nitrate-nitrite standard of 0.286 ug/L would be conservative, with an implicit margin of safety (MOS). 

11/19/2010 02:48 PM EST 2-4004
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Data points for representative spring systems were plotted with potential upper (0.44 ug/L) and lower (0.23 ug/L) 

protective limits. By visual inspection of graphs (EPA, 2010 - Figures 3-7 and 3-8), a change point anywhere between 

the FDEP and EPA values could be determined to be reasonable. A potential alternative could be to select the average 

of the high and low limits as the protective value: 0.335 ug/L, as referenced in Figure 3-10 (EPA, 2010b). 

No mention is made of springs that are subject to back-watering when the receiving water body levels rise, forcing 

water back up the spring run and into the spring boil. This can influence the determination of a stream as clear or 

colored, as most rivers have significantly higher colored water than springs. These effects may last for an extended 

period of time and subsequently bias results of sampling in both the spring boil and spring run. 

Comment ID 1362-1.001.005 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

D. Criteria for Springs and Clear Streams 

For springs and clear streams, EPA is proposing a nitrate-nitrite criterion that EPA asserts is based on experimental 

laboratory data and field evaluations that show algal growth in response to nitrate-nitrite concentrations. Again, EPA did 

not establish a defined impairment level or demonstrate a cause and effect relationship between the stressor and the 

response. Thus, EPA cannot demonstrate that its proposed criterion for springs is necessary to protect designated 

uses. 

Comment ID 1431-1.001.032 

Author Name: Levy K. 

Organization: Pinellas County Department of Environmental Management, Watershed Management Division 

Springs / Clear Streams 

The Nitrate-Nitrate criteria should focus only on springs as were the analyses conducted by FDEP. How will the criteria 

result in improved biological response in clear streams? This standard would result in public funds being expended 

without any clear guarantee there would be improved biological response. 

Comment ID 1464-1.001.012 

Author Name: Ettinger A. 

Organization: Mississippi River Collaborative et al. 

D. Springs, Spring Runs and Clear Streams 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Springs, spring runs and clear streams have sustained serious damage in Florida as a result of nitrogen pollution. The 

proposed nitrogen criteria for springs, spring runs and clear streams should be revised based on the evidence that 

shows that EPA should adopt nitrogen standards no higher than 230 ug/L. As explained by Dr. Burkholder, the 

laboratory and field studies showing the need for this standard are already in the record. 

Further, measuring compliance with the standard should be based on seasonal medians from samples taken at least 

monthly. 

Comment ID 1464-2.001.033 

Author Name: Ettinger A. 

Organization: Mississippi River Collaborative et al. 

More protective NOx criteria are needed to protect the designated uses of these systems - U.S. EPA (2010a, p. 4208) 

stated that over the past two decades, Florida's spring ecosystems have sustained pollution of groundwater especially 

by NOx from human land use changes and high population growth. In response to the high NOx availability, excessive 

algal mat accumulations, sometimes - remarkably - more than three feet thick, have been described in many of Florida's 

major springs (Stevenson et al. 2004, Pinowska et al. 2007). In particular, U.S. EPA (2010a, p.4210) described FDEP's 

analysis as having shown, based on laboratory studies under optimal conditions, that Plectonema (Lyngbya) wollei and 

Vaucheria sp. attain 90% of their maximal growth at concentrations of 230 ug NOx/L (0.230 mg/L) and 261 ug NOx/L 

(0.261 mg/L), respectively. 

Lyngbyatoxin-A and debromoaplysiatoxin, which can cause human disease (Burkholder 2002, 2009 and references 

therein), have been found in association with Plectonema blooms in Florida springs (Burns 2007). P. wollei also 

produces other toxins that can cause human disease and death (Burkholder 2009 and references therein). If under 

optimal conditions in the natural environment, a concentration of 230 ug NOx/L would support 90% of the maximal 

growth of potentially toxic P. wollei, and therefore this concentration would promote bloom conditions that would fail to 

protect the designated recreational uses of these waters. The natural environment is often not optimal for algal growth, 

however, and instead includes conditions such as sloughing, suboptimal light and temperature, possible losses from 

grazing and other factors (Whitton 1975). Because the natural environment is often not optimal for algal growth, a level 

of 230 ug NOx/L may be low enough to protect springs, spring runs, and clear streams from P. wollei blooms. 

Based on field data as well as the above laboratory data, the proposed level of 350 ug NOx/L would not be sufficiently 

protective: FDEP (2009a, pp.5-6) described change point analysis (Figure 2) as indicating that a threshold of 441-454 

ug NOx/L was "the lower range of nitrate concentrations for sites with excessive algal abundance." FDEP (2009a, p.6) 

asserted that by averaging the upper half-range and full range of the 95% confidence intervals around that range, and 

then applying that average confidence interval to 440 ug NOx/L, a sufficient margin of safety was derived at 350 ug 

NOx/L. However, examination of the data in Figure 2 of FDEP (2009a; same as Figure 4-9 in FDEP 2009b), as well as 

Figures 4-10 and 4-11 in FDEP (2009b, pp. 57-58), show that mean algal biomass and mean periphyton cell density 

begin to increase at a concentration of about 375 ug NOx/L. That is, the actual threshold appears to be at ~375 ug 

NOx/L rather than 440 ug NOx/L. Thus, the margin of safety should have been estimated around ~375 ug NOx/L, not 

440 ug NOx/L, supporting the need for a more protective criterion to protect designated uses of Class I and Class III 

11/19/2010 02:48 PM EST 2-4006
 
Chapter 2 - Comment Documents Springs and Clear Streams 

springs, spring runs, and clear streams affected by this toxic cyanobacterium. 

As mentioned, the historic actual reference condition in Florida springs was ~50 ug NOx/L (Maddox et al. 1992). These 

considerations of the laboratory and field data collectively support a nitrate criterion below 300 ug NOx/L for these 

systems (based on laboratory data, below 230 ug NOx/L), which would help to protect them from both toxic P. wollei 

blooms and nuisance overgrowth of Vaucheria. 

Comment ID 1474-1.001.006 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

For springs and clear streams, EPA is proposing a nitrate-nitrite criterion that EPA asserts is based on experimental 

laboratory data and field evaluations that show algal growth in response to nitrate-nitrite concentrations. 

Comment ID 1474-1.001.011 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

E. Standards for Springs, Spring Runs and Clear Streams. 

The proposed criteria for springs, spring runs and clear streams are focused on limiting nitrate-nitrite levels to such 

waters, based on the theory that groundwater inputs of this parameter have caused excessive plant growth to occur. 75 

Fed. Reg. at 4209. EPA notes that algal productivity in these waters “is primarily determined by the naturally high level 

of light availability of these waters.” 75 Fed. Reg. at 4208. EPA asserts, based on a series of studies, some occurring 

over decades, that nitrate-nitrite is an “important factor” that has been “linked” to ecological changes in springs. Based 

on these studies, EPA is recommending an annual average nitrate-nitrite value of 0.35 mg/l. EPA is recommending that 

this value be applied to spring runs and clear streams. Phosphorus is not being regulated since it is naturally high in 

these spring waters and does not appear to be the cause of impairment. 75 Fed. Reg. at 4209. EPA should also have 

taken into account the fact that springs in the Bone Valley and North Central regions also may have naturally high TP 

levels. Further, it should be noted that none of the information presented by EPA addresses unacceptable ecological 

changes in either spring runs or clear streams. Finally, EPA did not set any form of plant growth, water clarity or 

ecological impairment threshold in proposing the 0.35 mg/l nitrate-nitrite numeric criteria. EPA indicated it lacked data 

on these systems to set such impairment thresholds. Id. Thus, it is uncertain precisely what ecological improvement is 

anticipated to occur with the attainment of the proposed numeric objectives. The following details the concerns with the 

proposed nitrate-nitrite criteria. 

Comment ID 1474-1.001.147 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

4. Relationship between periphyton level and spring impairment is not defined. 

As part of the scientific justification EPA asserts a "strong relationship" between periphyton growth and nitrate-nitrite 

level has been demonstrated. 75 Fed. Reg. at 4209. However, nowhere does EPA specify what constitutes a "strong 

relationship." The statement is simply conclusory and unsupported. Elsewhere in the analysis EPA explains that it lacks 

available data on chlorophyll a for these systems. Id. It is not apparent how EPA can claim a strong relationship to plant 

growth and then acknowledge that it lacks plant growth data for these systems. The basic purpose of nutrient criteria is 

to limit excessive plant growth. If EPA lacks data sufficient to show plant growth is excessive in these systems or does 

not have data for these systems showing a correlation to excessive plant growth, criteria should not be proposed. 

Finally, EPA's assertion of a "strong relationship" must be documented with reliable information. The SAB recently 

rejected similar claims as unsupported. SAB Report, at 23-25. It is apparent that EPA has committed the same error 

once again. 

Comment ID 1474-1.001.148 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

5. No scientific justification for applying nitrate-nitrite water quality standards generally to clear streams or spring runs. 

The Agency proposes that the nitrate-nitrite values determined to be necessary to protect clear springs be applied to 

spring runs and streams. However, as noted previously, these are very different ecological settings. It is broadly 

recognized by the scientific community that streams and lakes have different responses to nutrient inputs. Stable spring 

environments are similar to lakes, not streams. EPA has presented no defensible scientific basis to include streams, 

clear or not, with springs. Likewise, EPA has not presented information showing spring runs exhibit the types of 

ecological changes occurring in some springs, as a result of changes in nitrate-nitrite groundwater quality. EPA's prior 

conclusion that TN levels are not correlated to stream impairment indicators is directly at odds with the position EPA is 

asserting with respect to clear streams. The agency has not demonstrated that this subset of streams (which includes 

most streams in Florida) actually is responding to low level nitrate-nitrite inputs when even higher levels of TN do not 

indicate adverse impacts. To the contrary, EPA's evaluation of available plant growth data for clear and unshaded 

streams confirmed that plants only "responded weakly to nutrient concentrations." TSD, Appendix B-11, at 5. 

EPA's primary rational for imposing these requirements on streams and spring runs is administrative, not scientific. 

Application of the 0.35 mg/l criterion to all waters and streams "could be useful from an assessment and management 

perspective" and could help to "identify trends that may indicate the need for specific controls of certain nitrogen 

sources..." 75 Fed. Reg. at 4211. Criteria are not intended to be adopted because they may help to "identify trends." 

The Agency claims that the need for application of the springs values to streams is supported by Appendix B-11. 

However, that analysis of Florida's rapid periphyton data does not show cause and- effect nor does it serve as an 

objective basis for concluding that nitrate-nitrite levels must be reduced because of periphyton growth. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

The document notes that "six principal factors may affect algal production in Florida streams, i.e., temperature, flow 

(velocity), turbidity (color), canopy cover, grazing and nutrients." TSD, Appendix B-11, at 1. The study was based on 

"visual measurements" of algal mat thickness and the estimated thickness was assigned a value of 0 (none) to 5 (high). 

Nowhere were these numeric values related to any actual biological or ecological impairment or violation of state 

narrative criteria. The purpose of the analysis was only to evaluate "potential causal relationships." The study did not 

claim to demonstrate cause-and-effect. Id. at 2. Change point analyses were used to determine where it appeared that 

nutrients or other factors were influencing the observations. Id. EPA's SAB specifically stated that such analyses do not 

represent cause-and-effect and do not provide information on whether or not the change point is biologically significant. 

SAB Report, at 23-24. The only "strong correlations" found in this analysis were with color, not nutrient levels as EPA 

has asserted. TSD, Appendix B-11, at 3. The document found only that nitrate-nitrite had a statistically significant 

"weak" relationship (not a "strong correlation") and further noted that the correlation was confounded by color that could 

also explain the reduction in algal mat thickness. Id. 

A review of the data plots confirms that the correlations are extremely poor. Typical r2 were in the range of 0.1 or less. 

See TSD, Appendix B-11, at 10-16. EPA's SAB review informed EPA that such weak relationships were not sufficient to 

justify defensible nutrient criteria. SAB Report, at 23-25. The data evaluated by EPA are so confounded that increasing 

nutrient concentrations produce both apparent increases and decreases in plant growth. See TSD, Appendix B-11, 

Figure B-11-4. Such information cannot be used to set defensible criteria. 

Comment ID 1474-1.001.151 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

1.�Nitrate-nitrite values have no defined impairment threshold. 

As with the stream and canal criteria, EPA's proposed criteria for springs, spring runs and clear streams are not related 

to a defined impairment threshold or any objective ecological metric that may be used to determine when uses are not 

longer impaired from nitrate-nitrite. The lack of any "response" variable prevents the regulated community as well as the 

regulators from identifying the springs that are actually nutrient impaired. Thus, under this proposal, all springs will be 

required to achieve the 0.35 mg/l value regardless of actual need. Moreover, since there is no defined ecological 

indicator of a healthy spring environment associated with the proposed criteria, it is not possible to determine if 

compliance has produced use protection. This is a critical deficiency that renders the proposed criteria not scientifically 

defensible. Finally, EPA is extending the results from springs, which are unique stable environments, to spring runs and 

all clear streams. These habitats are all very different and EPA provides no basis to evaluate precisely what plant 

growth problems were documented for such waters or what impairment threshold should be used in those systems. 

These are major technical deficiencies in the proposed approach. Claiming that a "link" exists does not provide an 

objective scientific framework for assessing the need or sufficiency of the proposed criteria. As with the lake criteria, 

EPA must identify the threshold impact that the criteria are intended to address. Without this factor the efficacy of the 

criteria is unknown. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1474-1.001.152 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

2. Methods used to set nitrate-nitrate values are merely correlations without confirmation of causation. 

EPA references a series of studies that appear to show that there is a relationship between increasing biological 

response (generally related to excessive plant growth) and increasing nitrate-nitrite levels. The analysis, however, 

indicates that many other factors may have influenced these results. TSD at 3-1. EPA acknowledges that only springs 

with less than 40 percent canopy or color less than 40 PCU show a relationship between nitrate-nitrite levels and plant 

growth. However, EPA does not limit the application of the stringent objectives to waters with reduced canopy, although 

its analysis supported that limitation. Various data sets are combined to reach these conclusions without any analysis of 

the specific differences between the varied spring environments that could explain the changes that are occurring. 

Without such an analysis of confounding factors, the correlations cannot demonstrate causation. EPA's SAB recently 

cautioned the agency that causation cannot be presumed from simple correlations. A mechanistic explanation of the 

phenomena being evaluated must be presented, considering the various habitat and other factors that could influence 

the results. SAB Report at 6. At a minimum, EPA needs to demonstrate how the changes in cell count and other 

correlations developed in the TSD translate into spring or spring run impairments. 

Comment ID 1474-1.001.153 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

3. The selected nitrate-nitrite level is not correlated to impacts due to the extremely long duration of the springs studies 

(up to 18 years). 

Based on some of the information presented (e.g., pictures of Weeki Wachee Springs), it is apparent that plant biomass 

has increased greatly over the years. Major confounding factors in the information presented in support of the proposed 

criteria are the different durations for the studies and the types of conditions that may have varied over information from 

a decades long study. Some studies were relatively short term (30 days) while others tracked impacts over an 18 year 

period. 75 Fed. Reg. at 4210. With regard to the short term growth rate studies, EPA asserts these studies provide "no 

evidence to suggest that the responses observed within a month under controlled lab settings equate to impairment of 

the designated use conditions experienced in State waters." 75 Fed. Reg. at 4211. Elsewhere EPA asserts that rapid 

periphyton surveys data had a "strong relationship" to nutrient levels. 75 Fed. Reg. at 4209. The duration over which 

this growth allegedly occurred, and the specific environmental setting that supported this result is nowhere discussed. 

One would expect that groundwater influences would occur over a very long duration, because the nutrient 

concentrations in such waters changes very slowly. Moreover, the spring environments are each unique and very 

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Chapter 2 - Comment Documents Springs and Clear Streams 

stable. Spring runs and streams have significant changes in flow and inputs occurring every year. How spring studies 

could be applied to these different environments is not explained; it is simply presumed. These differences must be 

addressed to produce a sound scientific approach. 

Comment ID 1474-1.001.154 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

6. Conclusions regarding EPA's proposed criterion for springs and clear streams. EPA's proposed criterion for Florida 

springs and clear streams is based on the approach proposed by Florida, which is a reference approach. While the 

State did have some laboratory data and field data showing increases in algal growth with increasing nitrate-nitrite 

concentrations in springs, without defined impairment levels and without a demonstrated cause-and-effect relationship 

between the stressor and the response, any criteria developed from these data cannot be said to be necessary to 

protect the designated use, contravening 40 C.F.R. 131.2. In clear streams and spring runs the State and EPA did not 

even find a correlation between the stressor and the response, much less a demonstration of cause-and-effect. Thus, 

the proposed criteria for clear streams and spring runs also cannot be said to be said to be necessary to protect 

designated uses. 

Comment ID 1474-2.001.006 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

Comment on FOIA Item #9 

The request asked: "On page 129 of the proposed standards, EPA states it will regulate nitrate/nitrite because it has 

been linked to many of the observed impacts in spring ecosystems. Please provide all documents which explain how 

this finding justifies the regulation of nitrate/nitrite in all clean streams, regardless of their physical attributes, such as the 

degree to which the water is spring fed, location, flow, depth, canopy, velocity, substrate, etc.)" 

Response: EPA identified its Technical Guidance Manuals, Ecoregional Criteria Documents, the National Strategy 

document for regional criteria, and its technical support document for the proposed standards as justification for the 

regulation of nitrate/nitrite in all clean streams. 

Comment: This request was tailored to EPA's specific decision to regulate nitrate/nitrite in Florida's clear streams. In 

response, the agency identified various national guidance that is generally related to nutrient criteria but does not 

anywhere explain the specific issue identified in the question. The Agency also provided the technical support 

document used to derive the standards, but this document does not provide the justification for the nitrate/nitrite 

decision. TFI does not agree with the Agency's decision to regulate nitrates/nitrite absent a demonstration that it is 

causing a harmful effect to clear streams. Without more, "a link to observed impacts" is insufficient grounds on which to 

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Chapter 2 - Comment Documents Springs and Clear Streams 

base such a regulatory decision. This aspect of the proposed rule should be withdrawn. 

To the extent EPA believes these documents explain EPA's position, please identify the specific portion of the 

document. 

Comment ID 1645-1.001.021 

Author Name: Griswold R. 

Organization: Destin Water Users 

Current regulations for all land-based effluent disposal activities have a total nitrogen standard equal to the drinking 

water standard MCL. Again, it should be kept in mind that the MCL is established to protect the most susceptible group 

in society. In this case, it is pregnant or nursing women. Particularly, the MCL is 10 milligrams per liter for drinking 

water. In the portion of the proposed rule applicable to springs (Section III.D) the proposed limit for springs is 0.35 mg/L 

for nitrite-nitrate which is only 3.5% of the current drinking water MCL. If the purpose of the limit is to protect human 

health, the MCL of 10 ppm is the recognized standard which is 28.5 times greater than the proposed limit for springs of 

0.35 mg/L. All land based effluent disposal activities have limits targeting the 10 mg/L limit for nitrite-nitrate for utilities. 

As such, the source of drinking water nitrite-nitrate violations is not utility-based unless they are regularly violating their 

operating permit which is highly unlikely and would already be subject to a regulatory compliance enforcement action. In 

summary, if the current nitrogen standard were applied to other sources of nitrogen as stringently as it is applied to 

utilities, there would be no violations of the MCL. 

Comment ID 1761-3.001.147 

Author Name: Merrill M. 

Organization: Hillsborough County 

III.D(2) Methodology for Deriving EPA's Proposed Criteria for Springs and Clear Streams 

III.D(2)(a) Derivation of Proposed Nitrate- Nitrite Criteria 

Statement: 

EPA reviewed Florida data, FDEP approach and analyses, and FDEP's proposed nitrate-nitrite criterion for springs and 

clear streams and has concluded that the FDEP approach and the values FDEP derived represent a scientifically sound 

basis for the derivation of these criteria. Comment: We appreciate that EPA utilized the extensive data and research 

from the FDEP in proposing the value of 0.35 mg/l. We note, however, that this value may be overly conservative given 

that excess biomass does not become persistent until nitrate-nitrite levels reach approximately 0.441 mg/l. We concur 

that a factor of safety is necessary to ensure protection of the water body, but wonder if adequate protection is achieved 

with a factor of safety on the order of 10 to 15 percent rather than the nearly 21 percent that is proposed. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1764-1.001.008 

Author Name: Mowry G. 

Organization: Marion County Stormwater Section 

The following are specific comments regarding EPA's Rivers and Streams Criteria and Springs/Clear Streams Criteria. 

6. Based on FDEP's determination and demonstration thereof that the spatial variability of total nitrogen can be related 

to wetland and spring influence, the County recommends that EPA consider a higher percentile of total nitrogen 

concentrations to account for the influence of wetlands or develop a criteria for Total Soluble Inorganic Nitrogen, or 

develop a nitrate criterion since nitrate has been clearly demonstrated to have a cause and effect in clear streams. [1] 

[1] Florida Department of Environmental Protection. June 2009. Technical Support Document: Development of Numeric 

Nutrient Criteria for Florida Lakes and Streams. 

Comment ID 1769-1.001.022 

Author Name: de la Parte, Jr. E. 

Organization: de la Parte & Gilbert, P.A. on behalf of City of Cocoa 

3. Methodology for Clear Stream/Spring Criteria 

The proposed nitrate-nitrite limit of 0.35 mg/L is not supported by sound science for several reasons. Results from the 

Stevenson et al. (2007) survey of 60 springs in Florida failed to show any correlation between the abundance of 

Lyngbya wollei, a common microalgae in Florida springs, and water column nutrient concentrations. Other factors may 

also affect growth rates of nuisance algae including current, water clarity, and sediment chemistry. Stevenson et al. 

(2007) found that abundance of Lyngbya wollei was correlated with the level of anthropogenic disturbance near the 

springs, as measured by the Landscape Development Intensity Index ("LDI"). This suggests that factors such as the 

turbidity of runoff entering a spring could have significant impacts on algae growth. 

Also, much of the water quality and spring vegetation information used was from sites in the northern part of the state, 

and the data used in the analysis that developed the proposed criteria were all from the Suwannee River system. 

Although spring distribution is higher to the north there are significant geological, climatic, and biological differences 

between the northern and central/southern portions of the state. The proposed rule and TSD present no documentation 

supporting the assumption that Suwannee River system spring data is representative of springs in different parts of the 

state, extending from Hillsborough County south to Sarasota County. It is important to recognize potential regional 

variability in the criteria. Regional differences in water quality are recognized in EPA's proposed stream, lake, and canal 

standards, and a similar analysis is warranted for springs, given the variation in state-wide geology. 

Finally, using only nitrite-nitrate to manage springs may not be sufficient in some cases. Although background 

phosphorus levels are high in some areas such as the Bone Valley formation, this is not a state-wide phenomenon and 

Stevenson et al. (2007) states that "N:P ratios in the water colunm and growth assays indicated that phosphorus is the 

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Chapter 2 - Comment Documents Springs and Clear Streams 

most limiting nutrient in many Florida Springs." 

For a complete discussion regarding Cocoa's technical connnents on the clear stream/spring criteria in the Proposed 

Rule, please refer to the Technical Discussion document attached hereto as Appendix "A". 

Comment ID 1770-1.001.046 

Author Name: de la Parte, Jr. E. 

Organization: de la Parte & Gilbert, P.A. on behalf of Plant City 

3. Methodology for Clear Stream/Spring Criteria 

The proposed nitrate-nitrite limit of 0.35 mg/L is not supported by sound science for several reasons. Results from the 

Stevenson et al. (2007) survey of 60 springs in Florida failed to show any correlation between the abundance of 

Lyngbya wollei, a common microalgae in Florida springs, and water column nutrient concentrations. Other factors may 

also affect growth rates of nuisance algae including current, water clarity, and sediment chemistry. Stevenson et al. 

(2007) found that abundance of Lyngbya wollei was correlated with the level of anthropogenic disturbance near the 

springs, as measured by the Landscape Development Intensity Index ("LDI"). This suggests that factors such as the 

turbidity of runoff entering a spring could have significant impacts on algae growth. 

Also, much of the water quality and spring vegetation information used was from sites in the northern part of the state, 

and the data used in the analysis that developed the proposed criteria were all from the Suwarmee River system. 

Although spring distribution is higher to the north there are significant geological, climatic, and biological differences 

between the northern and central/southern portions of the state. The proposed rule and TSD present no documentation 

supporting the assumption that Suwannee River system spring data is representative of springs in different parts of the 

state, extending from Hillsborough County south to Sarasota County, It is important to recognize potential regional 

variability in the criteria. Regional differences in water quality are recognized in EPA's proposed stream, lake, and canal 

standards, and a similar analysis is warranted for springs, given the variation in state-wide geology. 

Finally, using only nitrite-nitrate to manage springs may not be sufficient in some cases. Although background 

phosphorus levels are high in Some areas such as the Bone Valley formation, this is not a state-wide phenomenon and 

Stevenson et al. (2007) states that "N:P ratios in the water column and growth assays indicated that phosphorus is the 

most limiting nutrient in many Florida Springs." 

For a complete discussion regarding Plant City's technical comments on the clear stream/spring criteria in the Proposed 

Rule, please refer to the Technical Discussion document attached hereto as Appendix "A". 

Comment ID 1771-1.001.056 

Author Name: de la Parte, Jr. E. 

Organization: de la Parte & Gilbert, P.A. on behalf of Seminole County 

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Chapter 2 - Comment Documents Springs and Clear Streams 

3. Methodology for Clear Stream/Spring Criteria 

The proposed nitrate-nitrite limit of 0.35 mg/L is not supported by sound science for several reasons. Results from the 

Stevenson et al. (2007) survey of 60 springs in Florida failed to show any correlation between the abundance of 

Lyngbya wollei, a common microalgae in Florida springs, and water column nutrient concentrations. Other factors may 

also affect growth rates of nuisance algae including current, water clarity, and sediment chemistry. Stevenson et al. 

(2007) found that abundance of Lyngbya wollei was correlated with the level of anthropogenic disturbance near the 

springs, as measured by the Landscape Development Intensity Index ("LDI"). This suggests that factors such as the 

turbidity of runoff entering a spring could have significant impacts on algae growth. 

Also, much of the water quality and spring vegetation information used was from sites in the northern part of the state, 

and the data used in the analysis that developed the proposed criteria were all from the Suwannee River system. 

Although spring distribution is higher to the north there are significant geological, climatic, and biological differences 

between the northern and central/southern portions of the state. The proposed rule and TSD present no documentation 

supporting the assumption that Suwannee River system spring data is representative of springs in different parts of the 

state, extending from Hillsborough County south to Sarasota County. It is important to recognize potential regional 

variability in the criteria. Regional differences in water quality are recognized in EPA's proposed stream, lake, and canal 

standards, and a similar analysis is warranted for springs, given the variation in state-wide geology. 

Finally, using only nitrite-nitrate to manage springs may not be sufficient in some cases. Although background 

phosphorus levels are high in some areas such as the Bone Valley formation, this is not a state-wide phenomenon and 

Stevenson et al. (2007) states that "N:P ratios in the water column and growth assays indicated that phosphorus is the 

most limiting nutrient in many Florida Springs." 

For a complete discussion regarding Seminole County's technical comments on the clear stream/spring criteria in the 

Proposed Rule, please refer to Technical Discussion document attached hereto as Appendix "A". 

Comment ID 1772-1.001.050 

Author Name: de la Parte, Jr. E. 

Organization: de la Parte & Gilbert, P.A. on behalf of City of Titusville 

3. Methodology for Clear Stream/Spring Criteria0 

The proposed nitrate-nitrite limit of 0.35 mg/L is not supported by sound science for several reasons. Results from the 

Stevenson et al. (2007) survey of 60 springs in Florida failed to show any correlation between the abundance of 

Lyngbya wollei, a common microalgae in Florida springs, and water column nutrient concentrations. Other factors may 

also affect growth rates of nuisance algae including current, water clarity, and sediment chemistry. Stevenson et al. 

(2007) found that abundance of Lyngbya wollei was correlated with the level of anthropogenic disturbance near the 

springs, as measured by the Landscape Development Intensity Index ("LDI"). This suggests that factors such as the 

turbidity of runoff entering a spring could have significant impacts on algae growth. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Also, much of the water quality and spring vegetation information used was from sites in the northern part of the state, 

and the data used in the analysis that developed the proposed criteria were all from the Suwannee River system. 

Although spring distribution is higher to the north there are significant geological, climatic, and biological differences 

between the northern and central/southern portions of the state. The proposed rule and Technical Support Document 

present no documentation supporting the assumption that Suwannee River system spring data is representative of 

springs in different parts of the state, extending from Hillsborough County south to Sarasota County. It is important to 

recognize potential regional variability in the criteria Regional differences in water quality are recognized in EPA's 

proposed stream, lake, and canal standards, and a similar analysis is warranted for springs, given the variation in statewide geology. 

Finally, using only nitrite-nitrate to manage springs may not be sufficient in some cases. Although background 

phosphorus levels are high in some areas such as the Bone Valley formation, this is not a state-wide phenomenon and 

Stevenson et al. (2007) states that "N:P ratios in the water column and growth assays indicated that phosphorus is the 

most limiting nutrient in many Florida Springs." 

For a complete discussion regarding the City of Titusville's technical comments on the clear stream/spring criteria in the 

Proposed Rule, please refer to the Technical Discussion document attached hereto as Appendix "A". 

Comment ID 1773-1.001.051 

Author Name: de la Parte, Jr. E. 

Organization: de la Parte & Gilbert, P.A. on behalf of Orlando Utilities Commission 

3. Methodology for Clear Stream/Spring Criteria 

The proposed nitrate-nitrite limit of 0.35 mg/L is not supported by sound science for several reasons. Results from the 

Stevenson et al. (2007) survey of 60 springs in Florida failed to show any correlation between the abundance of 

Lyngbya wollei, a common microalgae in Florida springs, and water column nutrient concentrations. Other factors may 

also affect growth rates of nuisance algae including current, water clarity, and sediment chemistry. Stevenson et al. 

(2007) found that abundance of Lyngbya wollei was correlated with the level of anthropogenic disturbance near the 

springs, as measured by the Landscape Development Intensity Index ("LDI"). This suggests that factors such as the 

turbidity of runoff entering a spring could have significant impacts on algae growth. 

Also, much of the water quality and spring vegetation information used was from sites in the northern part of the state, 

and the data used in the analysis that developed the proposed criteria were all from the Suwannee River system. 

Although spring distribution is higher to the north there are significant geological, climatic, and biological differences 

between the northern and central/southern portions of the state. The proposed rule and TSD present no documentation 

supporting the assumption that Suwannee River system spring data is representative of springs in different parts of the 

state, extending from Hillsborough County south to Sarasota County. It is important to recognize potential regional 

variability in the criteria. Regional differences in water quality are recognized in EPA's proposed stream, lake, and canal 

standards, and a similar analysis is warranted for springs, given the variation in state-wide geology. 

Finally, using only nitrite-nitrate to manage springs may not be sufficient in some cases. Although background 

11/19/2010 02:48 PM EST 2-4016
 
 

Chapter 2 - Comment Documents Springs and Clear Streams 

phosphorus levels are high in some areas such as the Bone Valley formation, this is not a state-wide phenomenon and 

Stevenson et al. (2007) states that "N:P ratios in the water column and growth assays indicated that phosphorus is the 

most limiting nutrient in many Florida Springs." 

For a complete discussion regarding OUC's technical comments on the clear stream/spring criteria in the Proposed 

Rule, please refer to Technical Discussion document attached hereto as Appendix "A". 

Comment ID 1777-2.001.030 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

Springs and Clear Streams (Section III.D) 

1. The nitrate-nitrite criteria as proposed should be applicable primarily to springs and spring runs as the field and 

laboratory work conducted was primarily for this purpose and recognizes the unique nature of springs. 

Comment ID 1777-2.001.118 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

III.D(2) Methodology for Deriving EPA's Proposed Criteria for Springs and Clear Streams
 

III.D(2)(a) Derivation of Proposed Nitrate- Nitrite Criteria
 

Statement:
 

EPA reviewed Florida data, FDEP approach and analyses, and FDEP's proposed nitrate-nitrite criterion for springs and
 

clear streams and has concluded that the FDEP approach and the values FDEP derived represent a scientifically sound
 

basis for the derivation of these criteria.
 

Comment:
 

We appreciate that EPA utilized the extensive data and research from the FDEP in proposing the value of 0.35 mg/l.
 

We note, however, that this value may be overly conservative given that excess biomass does not become persistent
 

until nitrate-nitrite levels reach approximately 0.441 mg/l. We concur that a factor of safety is necessary to ensure
 

protection of the water body, but wonder if adequate protection is achieved with a factor of safety on the order of 10 to
 

15 percent rather than the nearly 21 percent that is proposed.
 

Comment ID 1791-1.001.001 

Author Name: Knight R. 

Organization: Wetland Solutions, Inc. 

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Chapter 2 - Comment Documents Springs and Clear Streams 

I have had the good fortune of studying the ecology of Florida's artesian springs over a period of 31 years. During my 

recent work (2002 through 2010), it has become apparent that the water quality of these springs has been severely 

changed as a result of rising concentrations of nitrate nitrogen in the waters of the Floridan aquifer. Based on the 

research I have conducted, it is increasingly evident that elevated nitrate levels in many of the largest springs in Florida 

are in turn affecting springs ecology. While no conclusions concerning these ecological effects of nitrate are final at this 

time, it appears likely that elevated nitrogen concentrations result in eutrophication in springs, resulting in a continuum 

of responses along the subsidy-stress gradient described by E.P odum (1979). 

Springs with unaltered nitrate nitrogen levels (20 to 50 ug/L) are dominated by a greater variety of submerged aquatic 

vegetation (SAV) such as eelgrass, strap-leaf sagittaria, chara, ludwidgea, etc. that have a thin coating of attached 

algae dominated by diatoms. These systems have moderate primary productivity and a relatively high diversity and 

abundance of dependent aquatic fauna. At intermediate nitrate concentrations (50 to 400 ug/L), springs are dominated 

by a lower diversity of submerged aquatic plants with greater quantities of attached algae biomass and become more 

productive, supporting even higher populations of fish and other wildlife. As nitrate concentrations rise above these 

intermediate levels (greater than 200 to 400 ug/L), springs become increasingly dominated by filamentous algae, both 

attached and benthic. These algal populations can become excessive, replacing the natural submerged macrophytes 

entirely. Ecosystem productivity estimates in these springs indicate that gross primary productivity declines as spring 

systems shift from the better adapted SAV and algae plant communities to monocultures of benthic algae. Populations 

of fauna in these algal dominated springs appear to be reduced in diversity and biomass. These shifts and their 

documented effects on springs ecosystems are described in the attached references. 

Based on my work and the work published by others, I would conclude that any nitrate concentration in springs greater 

than the normal background (somewhere less than 100 ug/L) is causing an imbalance in the ecology of these aquatic 

ecosystems. Based on existing data it appears that conclusive (measurable) changes are generally limited to nitrate 

nitrogen concentrations above about 200 to 400 ug/L. Within these realities I believe that data support numeric criteria 

for nitrate in springs in this range. Based on the need for conservatism in environmental protection, I would argue for 

limits at the lower end of this range until more data can be obtained to better defend the cause-effect relationship 

between this nutrient and springs response. 

A very important consideration in the discussion of the effects of elevated nitrate nitrogen on springs ecology is the 

documented wide-spread contamination of the Floridan aquifer with this nutrient. I am attaching a map I prepared to 

illustrate the extent and severity of this problem. As you can see from these data, human activities and implementation 

of existing waste management practices in Florida have resulted in a legacy of nitrate in our aquifer. This appears to be 

a problem that transcends the effects on springs alone and must be reversed if there is any hope of springs recovery. 

Thank you for the opportunity to share these comments as you deliberate your implementation of numeric nutrient 

criteria for Florida's springs. 

[Original comment letter contains additional data on springs. See original comment letter.] 

Comment ID 1805-3.001.133 

Author Name: Gallagher J. 

11/19/2010 02:48 PM EST 2-4018
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Organization: Pasco County 

III.D(2) Methodology for Deriving EPA’s Proposed Criteria for Springs and Clear Streams 

III.D(2)(a) Derivation of Proposed Nitrate¬Nitrite Criteria 

Statement:
 

EPA reviewed Florida data, FDEP approach and analyses, and FDEP’s proposed nitrate-nitrite criterion for springs and
 

clear streams and has concluded that the FDEP approach and the values FDEP derived represent a scientifically sound
 

basis for the derivation of these criteria.
 

Comment:
 

We appreciate that EPA utilized the extensive data and research from the FDEP in proposing the value of 0.35 mg/l.
 

We note, however, that this value may be overly conservative given that excess biomass does not become persistent
 

until nitrate-nitrite levels reach approximately 0.441 mg/l. We concur that a factor of safety is necessary to ensure
 

protection of the water body, but wonder if adequate protection is achieved with a factor of safety on the order of 10 to
 

15 percent rather than the nearly 21 percent that is proposed.
 

Comment ID 1810-1.001.013 

Author Name: Young L. 

Organization: Clean Water Network of Florida 

D. Springs, spring runs and clear streams 

Springs, spring runs and clear streams have sustained serious damage in Florida as a result of nitrogen pollution. The 

proposed nitrogen criteria for springs, spring runs and clear streams should be revised based on the evidence that 

shows that EPA should adopt nitrogen standards no higher than 230 ug/L. As explained by Dr. Burkholder, the studies 

showing the need for this standard, both laboratory and field studies, are already in the record. 

Comment ID 1836.001.043 

Author Name: Moore D. 

Organization: Southwest Florida Water Management District 

D. Proposed Numeric Nutrient Criteria for the State of Florida's Springs and Clear Streams 

32 . USEPA's approach of using the single nitrate-nitrite criterion of 0 .35 mg/L for all springs and clear streams is 

inappropriate . USEPA should instead develop system-specific nitrate-nitrite targets (page 4209, proposed rule). 

SWFWMD's experience in the spring-fed Kings Bay/Crystal River system suggests that it is possible to have biological 

11/19/2010 02:48 PM EST 2-4019
 
Chapter 2 - Comment Documents Springs and Clear Streams 

impacts at nitrate-nitrite levels that are lower than the proposed standard. Kings Bay, where nitrate-nitrite levels are at 

or below 0.35 mg/L, has shown tremendously high levels of filamentous algae accumulation as well as large decreases 

in water clarity (Southwest Florida Water Management District 2000 ; Jacoby et al. 2007) . Alternatively, Rainbow 

Springs has maintained relatively low levels of filamentous algae and excellent water clarity, although nitrate-nitrite 

levels in the system are approaching 2 mg/L (Southwest Florida Water Management District 2004) . Further, a recent 

review has cast doubt on water column nitrogen as the primary driver of the proliferation of filamentous algae in springs, 

noting that levels of dissolved oxygen and grazer abundance were better predictors of algal abundance than total 

nitrogen (Heffernan et al . 2010) . Finally, long-term monitoring of the responses of enriched coastal ecosystems to 

nitrogen abatement suggests that, rather than a mechanistic return to a previous state, spring responses to reversals of 

eutrophication will be unpredictable (Duarte et al . 2009). Since there are factors other than nitrate enrichment that may 

drive increases in algal abundance and since responses to nutrient abatement may be unpredictable, the SWFWMD 

supports using an iterative process to develop SSACs for individual spring systems, where new information is 

incorporated into management and regulation of each system as it becomes available (page 136, proposed rule). 

Comment ID 1839-1.001.003 

Author Name: Cohen M. 

Organization: University of Florida, Florida International University and University of Georgia 

EPA's proposed strategy for regulating nutrient concentrations in lotic (flowing water) systems, in which both local and 

downstream consequences are considered, is both logical and appropriate. The nitrogen loads in water discharging 

from Florida's springs are likely to contribute to over-enrichment in downstream water bodies, particularly those that are 

historically N-limited. As such, regulatory attention is warranted, and load reductions needed. Our own research focuses 

to a significant degree on the processing and fate of N in spring-fed rivers, and we hope that our findings about the 

mechanisms of N removal will be of use in ultimately helping enumerate the downstream protective values (DPVs) for 

springs. 

Comment ID 1839-1.001.004 

Author Name: Cohen M. 

Organization: University of Florida, Florida International University and University of Georgia 

Despite our over-arching support for increased water quality protection that will reduce nitrate concentrations in springs, 

we find little evidence to support the contention that the major ecological changes that have occurred in spring 

ecosystems over the last 50 years are primarily a response to nitrate enrichment. The attached manuscript, published in 

April 2010 in the journal Ecological Applications, summarizes a lengthy investigation of the available data and potential 

alternatives. In particular, we focus on the proliferation of nuisance levels of benthic filamentous algae, which we 

believe is the principal symptom upon which management is based. There are several lines of evidence that would 

confirm or refute nitrogen enrichment as the principal cause of the observed increases in the importance of benthic 

filamentous algae. In the paper we expound on each of these, and find evidence that leads us to conclude that nitrogen 

enrichment provides little explanatory power for understanding the status and trends of algal abundance in spring 

11/19/2010 02:48 PM EST 2-4020
 
Chapter 2 - Comment Documents Springs and Clear Streams 

ecosystems. 

In the case of Florida's springs, the attached paper also suggests an alternative hypothesis about the proliferation of 

algae in springs that is more consistent with the observed data, namely that potential declines in invertebrate grazer 

populations (such as gastropods) may be responsible for the accumulation of algal biomass in springs. Moreover, 

subsequent observational findings strongly support the link between gastropod density and algal cover, and also 

support the hypothesis that spring-vent dissolved oxygen may be one important factor controlling the density of grazers. 

Ongoing experimental efforts will allow continued refinement of this model, but the salient points are that a) nitrate 

concentrations provide little statistically significant explanatory power for algal cover or biomass in Florida springs, b) 

that mechanisms other than increased growth (e.g., reduced loss rates) can lead to algal biomass accumulation in 

Florida springs, c) that algal grazers in Florida springs are sensitive to low dissolved oxygen levels, which can 

apparently vary dramatically over time, and d) that the loss of grazers in Florida springs may lead to high algal densities 

that are resistant to subsequent grazer control. These findings indicate a need to address other changes in springs in 

addition to increasing nitrate concentrations when developing protective standards for these systems and when trying to 

understand the environmental drivers of ecological change. In particular, we suggest that hydrogeologic controls and 

ecological consequences of dissolved oxygen variation in springs, which may follow from the cumulative impacts of 

regional water withdrawal and climatic change, are likely to be critically important for better understanding and 

mitigating observed ecological changes in Florida springs. 

Comment ID 1839-1.001.005 

Author Name: Cohen M. 

Organization: University of Florida, Florida International University and University of Georgia 

To summarize, our work finds increasingly compelling evidence that obviates the direct role of nutrients in algal 

proliferation in Florida springs. This finding makes it difficult to defend EPA's current ecological justification, which is 

based on a presumption of direct links between nitrate and algal proliferation, for the proposed 0.35 mg/L nitrate criteria 

in Florida's springs and clear water stream systems (Federal Register 2010, pg. 4210). However, we concur that highly 

elevated nitrate levels observed in many of Florida's springs reflect the inherent vulnerability of these karst catchments 

to nitrate contamination. Because natural or background nitrate levels in Florida springs are generally between 0.05 ­

0.2 mg/L, a numeric nitrate criteria of 0.35 mg/L for these systems is consistent with the imperative to restore and/or 

maintain designated uses for N-limited downstream ecosystems such as the Lower St. Johns River and Suwannee 

Estuary, that receive substantial spring flow inputs. Thus, we suggest that EPA adjust its rationale for the proposed 

numeric nitrate criteria in springs to reflect inherent geologic vulnerability of springsheds to N contamination, 

demonstrated N enrichment history in springs, and clear risks to downstream ecosystems from N that emerges from 

spring systems. These rationales for numeric nitrate criteria in Florida springs are, in our view, both reasonable and 

supported by a much stronger body of available scientific evidence than the ecological justification currently provided by 

EPA. 

Comment ID 1887-1.001.005 

Author Name: Manson D. 

11/19/2010 02:48 PM EST 2-4021
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Organization: Manson Law Group, P.A. on behalf of Nestle Water North America 

EPA's approach to springs and spring run criteria 

We have closely reviewed the data and procedures used by FDEP in developing the proposed nitrate criterion for 

springs and spring runs. From both field and laboratory investigations, there is a strong relationship between nitrate 

concentrations and the growth and abundance of certain periphyton algal species in springs and spring runs. The 

laboratory studies found that certain algal species reached maximum rates of growth at nitrate (NOx) concentrations 

between 0.230 mg/L and 0.644 mg/l., In field surveys, a common nuisance species of macroalgae was found to have a 

"threshold" in its growth response at 0.454 mg/L nitrate via regression tree (or change-point) analysis. Growth of at least 

one algae species (Lyngbya wollei) that was associated with the level of anthropogenic effects of springs was not 

correlated with nitrate levels. In a study of periphyton in the Suwannee River and its tributaries, a change-point analysis 

identified a statistically significant change in periphyton between 0.286 and 0.401 mg/L nitrate for cell density and 

between 0.401 and 0.420 mg/L nitrate for biomass . When additional years ofdata were included, the statistically 

significant change-point for both cell density and biomass was 0.440 mglL nitrate. 

Although the majority of the thresholds in periphyton response were found to be above 0.400 rng/L, FDEP decided to 

adjust the nitrate target with an additional "safety factor" intended to prevent nuisance algae levels from occurring, 

which involves some degree of arbitrary decision-making with respect to the magnitude of that factor . Therefore, 

although there may be a relationship between nuisance algal growth and nitrate concentrations, we find the value 

derived by DEP (0.35 rng/L nitrate) may be overprotective for at least some Florida springs and spring runs. The EPA 

has proposed the ability to modify nitrogen and phosphorus criteria for lakes based on whether the chlorophyll a 

criterion is met, because of the "range of uncertainty" between nutrient levels and the biological response. A similar 

modification procedure is also reasonable for springs and spring runs, which could provide for nitrate levels up to at 

least 0.44 mg/L, where regular biological monitoring indicates acceptable levels of periphyton in a spring or spring run. 

We recommend that EPA revise its rule to allow flexibility where biological conditions indicate attainment of designated 

uses, as dictated by periphyton conditions. 

The majority of data used to set the springs nitrate criterion were collected in a small geographic area in north-central 

Florida, which limits the inference space of the results used to set the nitrate criterion to a limited region. Given that the 

underlying geology and climate are very different in other parts of the state, water quality and other physical 

characteristics (i.e. temperature) in panhandle or peninsular springs may deviate from the conditions seen in the springs 

that were studied. Springs in the Bone Valley, Panhandle, and Peninsula EPA NWR have chloride concentrations two 

orders of magnitude higher than North Central springs (FDEP IWR Run 35 database) . The North Central region springs 

also have phosphorus concentrations above those in regions that are not on the Hawthorn Formation (i.e. Panhandle), 

and phosphorus concentrations were shown to affect the rate ofperiphyton growth along with nitrate in springs 

(Stevenson et al. 2007). Water temperature, an important characteristic of Florida springs that probably contributes to 

the strong relationship between nutrients and algae growth , is several degrees warmer in Peninsula and Bone Valley 

springs than in North Central springs. With all of these regional differences in springs, it is important for the EPA to 

conduct confirmatory studies in non-North Central springs to determine if the proposed nitrate criterion is appropriate for 

all areas. 

Although the results of these studies indicate that there is a statistically significant threshold in the response of 

periphyton to nitrate concentrations, none of the laboratory or streams studies cited by the EPA actually address the 

11/19/2010 02:48 PM EST 2-4022
 
Chapter 2 - Comment Documents Springs and Clear Streams 

concept of designated use. The goal of nutrient criteria should not be to set standards at levels found at theoretical 

"natural" background levels (Smith et al. 2003). Setting numeric nutrient criteria above the levels that would have been 

found before anthropogenic effects occurred may still be protective of designated use. When using the results of 

descriptive studies, such as those field studies used for the development of the nitrate criterion, one cannot assume 

causal relationships or biological significance, even when statistically significant correlations or change-points have 

been found (Clements et al. 2002, Suter 2001). 

Original comment letter contains additional information in Figure 1. Florida springs, including those visited in Florida 

Geological Survey (FGS) 2004. Adapted from Brown et al. 2008. See original comment letter. 

Comment ID 1887-1.001.006 

Author Name: Manson D. 

Organization: Manson Law Group, P.A. on behalf of Nestle Water North America 

Potential issues with nitrate criterion analysis 

Change-point analysis is designed to identify statistical significant changes in biological response along environmental 

gradients by maximizing the differences in means or variances between the samples on either side of a threshold (King 

and Richardson 2003, Qian et al. 2003). King and Richardson (2003) stated, "A final consideration when using [changepoint analysis] is that it is just a statistical tool, and any tool can be used inappropriately...change point analysis may 

detect a statistical change in data that may not represent a biologically significant change - clearly, the definition of 

biological significance is a subjective one and will vary among scientists and decision-makers." Other authors remind 

readers that the change-points that they have found only suggest a change in response, but not necessarily that the 

change in response would result in a change in the designated use or other imbalance in the community (Qian et al. 

2003). While change-point analysis is suited to examining ecological communities for threshold responses because of 

its relaxed assumptions (Brenden et al. 2008), there are several potential issues that should be addressed. 

Many authors using change-point analysis recommend that more than one biological response variable (additional taxa) 

and/or experimental data should be used to confirm any single analysis of change-points for biological communities that 

are to be used for setting nutrient criteria (King and Richardson 2003, Stevenson et al. 2008, Baker and King 20 I0). 

Different species or trophic levels may be more or less sensitive to a nutrient gradient, and it is important to link these 

various thresholds to the protection of the designated use for that particular waterbody (Qian et al. 2003) . Although the 

FDEP did conduct some laboratory experiments on periphyton response to nitrate levels, the thresholds found in the 

experiment were derived using different statistical methods, did not necessarily agree with the thresholds found in field 

studies, and had a very wide range of values for the individual species considered. In addition, one algae species 

commonly linked to anthropogenic disturbance (Lyngbya wollei) did not show a relationship with nitrate concentrations 

in these studies. To date, there are no rigorous spring studies that show a concurrent change in spring benthic 

macroinvertebrates or fish in response to changes in nitrate levels or periphyton density and community composition 

(Brown et al. 2008). 

Any statistically-significant threshold is subject to uncertainty, so re-sampling methods such as bootstrapping should be 

used to identify a range of probable threshold values (King and Richardson 2003, Weilhoefer and Pan 2008). This type 

11/19/2010 02:48 PM EST 2-4023
 
Chapter 2 - Comment Documents Springs and Clear Streams 

of analysis works better on non-linear relationships; otherwise the uncertainty will be very high (King and Richardson 

2003). If the confidence interval around the change-point is very wide, as it is in some of the studies the DEP used for 

the nitrate criterion, then the biological significance of the change-point may be weak. In that case, it may not be 

appropriate to assume that the lower end of the confidence interval is more protective. In these analyses, the EPA only 

identified the first change-point of each distribution, but multiple change-points could be present, with a statistically 

stronger change-point potentially masking a more biologically significant change-point (King and Richardson 2003, 

Brenden et al. 2008). Given the inherent uncertainty present in any threshold identified by change point analysis, the 

EPA should account for that uncertainty in the assessment portion of their criteria. Springs with nitrate concentrations 

very close to the criterion of 0.35 mg/L will experience year-to-year variation in concentrations by random chance that 

may cause them to violate the duration and frequency standards proposed by the EPA, even though there is no 

indication that these streams are impaired for their designated use. In addition, the data used in the supporting studies 

was not evaluated on an annual basis. A more appropriate application of the proposed criterion would be to apply it 

according to the IWR binomial methodology (e.g. not to be exceeded more than 10% of the time over the verified period 

with a minimum 80% confidence level using a binomial distribution (FAC 62-303.320). 

Change-point analysis is one tool that may be used for identifying potential nutrient criteria for flowing waters. For the 

studies that the EPA has cited in its nitrate criterion, however, the authors have not reported enough information on the 

method and program used for change-point analysis, the goodness-of-fit and uncertainty measures associated with 

those tests, and any alternate change-points that may be present. In addition to providing more information to validate 

the findings ofthe field periphyton studies, the EPA should expand the laboratory studies to include the same type of 

change-point analysis if they are to compare the results of field and laboratory studies directly. The change-point used 

by the EPA for springs and spring runs might be made more robust if biological responses at higher trophic levels were 

analyzed for potential thresholds. The EPA should also conduct studies in other regions of Florida to determine if the 

responses shown in the North Central spring studies hold true in other spring systems. 

Comment ID 1887-1.001.007 

Author Name: Manson D. 

Organization: Manson Law Group, P.A. on behalf of Nestle Water North America 

Potential management issues for springs criterion 

Although the springs nitrate criterion is more robust in many ways than numeric nutrient criteria for other waters 

proposed by the EPA, given that it is supported by field and laboratory dose-response relationships, the EPA does not 

address how difficult it will be to enforce and manage spring nitrate levels. The springs and spring nitrate criteria are 

actually a regulation of groundwater, rather than surface water. The hydrologic dynamics of springs and groundwater 

are complex and very difficult to understand. Karst features are in a continuous flux of dissolution, leading to a porous 

non-uniform matrix, numerous subsurface flow pathways, sinkhole connections between surface and groundwater, 

conduits that deposit water outside the springshed, and other features that make determining anthropogenic nitrate 

sources for a particular spring very difficult (Brown et al.2008). 

In surface waters, nutrient management activities often focus on permitted point source discharges by introducing some 

percent reduction into their NPDES and MS4 permits. For non-point sources, visual inspections or a GIS-based review 

11/19/2010 02:48 PM EST 2-4024
 
Chapter 2 - Comment Documents Springs and Clear Streams 

may help identify potential large sources of nutrients to surface waters based on their proximity to surface water, 

presence of ditches, use of high-intensity irrigation, and density of nutrient sources (septic tanks, cattle). For springs, 

the identification of nutrient sources is more complex. Point source dischargers are not permitted in springs, but some 

point source discharges to groundwater (stormwater, treated wastewater, concentrated animal feeding operations) may 

be regulated by the EPA under the Clean Water Act if the location of the discharge to groundwater represents a 

significant nexus to water quality in navigable waters (Brown et al. 2008). However, recent studies have shown that 

mineralized fertilizer is the primary source of nitrate in Florida springs compared to other sources (wastewater, spray 

fields, storm water, septic tanks, etc.) (Katz et al. 2004, Brown et al. 2008). Non-point sources, such as agricultural 

stormwater and irrigation, are specifically exempted from the Clean Water Act, and are subject only to State law. These 

non-point sources of nitrate may be the primary focus of enforcement and management activities for the springs 

criterion, but the enforcement of any nutrient reductions for non-point sources is often voluntary unless adopted by rule 

by the FDEP, water management districts, or the Department of Agriculture and Consumer Services (DACS). 

Although studies have found that many spring nitrate sources are anthropogenic, and much of that anthropogenic 

nitrate comes from mineralized fertilizer (Brown et al. 2008, Phelps 2004, Toth 2003, Katz et al. 1999), the specific 

source locations are often difficult to identify. Isotope ratio studies may help identify whether the majority of the nitrate in 

a spring is from animal/human waste versus mineralized fertilizer, but the results are very generalized and do not 

identify a specific source. Studies have shown that water emanating from springs may have entered the ground 

decades in the past (Katz et al. 200 I), and management priority areas have been developed based on the estimated 

travel time to springs (Brown et al. 2008). Because of the mixture of old and new water sources for most springs, 

nutrients that have been applied to the land surface prior to the enforcement of the proposed nitrate criterion may have 

affects on groundwater for many years after management activities are implemented, so the proposed nitrate criterion 

may have little effect for some time. This is difficult to resolve in light of the EPA's proposed Restoration Water Quality 

Standards, which may be particularly applicable to springs with elevated nitrate levels, but which provide a maximum of 

20 years for achieving compliance. Most current agricultural BMPs (precision agriculture, irrigation management, tail 

water recovery, etc.) are focused on reducing nutrient or mineral discharges to surface water rather than infiltration to 

groundwater, and some BMPs, like stormwater detention, may actually increase seepage to groundwater (Brown et al. 

2008). 

In addition, the amount of nitrate that leaches from the land surface is not necessarily proportional to the amount 

applied or the area over which it is spread. Certain geologic features , such as karst, could increase the infiltration of 

nitrate to springs in certain locations, while areas with intact confining layers (Hawthorn Group of phosphatic clays) may 

have lower infiltration rates (Brown et al 2008). Although the nitrogen loading for a particular land-use activity would be 

similar across the state, in unconfined aquifer regions, the landscape has less time to denitrify, leading to nitrate loads 

to groundwater two orders of magnitude higher than in areas with a confined aquifer (Brown et al. 2008). The sphere of 

influence for a particular spring may extend considerably beyond relatively well-mapped cavern systems, and the 

cavern systems themselves may extend for many miles (Brown et al. 2008, FGS 2004). This makes enforcement of 

nitrate standards difficult and potentially very unfair; citizens with operations closer to springs may be more heavily 

affected by enforcement of the nitrate criterion even though significant nitrate sources may exist father afield. Dye tracer 

studies, modeling of subsurface flows, and hydrochemical facies analysis are possible methods used to identify 

connections and/or transport times to particular springs, but those studies are expensive and rely on a number of critical 

assumptions about matrix characteristics and flow velocity (Brown et al 2008). These types of studies would only 

confirm that a particular site is connected to the spring or that a certain category of anthropogenic activity is the primary 

source of nitrate, not that a specific location, farm, or development is the significant source of nitrate. 

11/19/2010 02:48 PM EST 2-4025
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Although springs typically flow from the boil to spring runs and on to other surface waters, during periods of high rainfall, 

back flow from surface waters into springs is quite common (negative spring flow). This backflow from surface water 

may change the water quality in springs and spring runs considerably, raising color, dissolved oxygen, salinity, and 

temperature range (FDEP IWR Run 35 database). When evaluating the nitrate criterion for Florida spring and spring 

runs, only periods of positive spring flow should be used to assess impairment, and special provision should also be 

made for the time period during which surface water that entered a spring is emerging as surface streamflows decline. 

Comment ID 2030-1.001.005 

Author Name: Long A. 

Organization: 

Springs have sustained serious damage in Florida as a result of nitrogen pollution. The proposed nitrogen criteria for 

springs, spring runs and clear streams should be revised based [strikeout: on the evidence that is already in the record] 

-> on evidence I have seen in BMAP DEP meetings} showing that EPA should adopt nitrogen standards no higher than 

230 ug/L. 

Comment ID 2045-1.001.002 

Author Name: Tonsmeire D. 

Organization: Apalachicola Riverkeeper 

Impacts to the swimmable and fishable waters of the Apalachicola Basin are significant. In the Chipola River Basin, the 

largest tributary to the Apalachicola River in Florida, nutrient problems are most pronounced in the springs of Jackson 

County. Jackson Blue Spring, one of Florida's 33 first magnitude springs, has documented water quality impacts from 

agricultural applications and activities that have occurred in years past. High nutrient loads have caused impacts 

including an influx of non-native plant growth and algae blooms which have severely impacted the native vegetation and 

water quality of the spring run and Merritts Millpond associated with Jackson Blue Spring. The standard established for 

the Jackson County springs by EPA is 0.35 m/l nitrates as an annual mean. FDEP recommended using 0.35 m/l on a 

monthly mean, which is actually a more restrictive measure. The current nitrate level found in Jackson Blue Spring is 

almost 4 m/l, roughly 10 times the standard proposed by EPA and FDEP. Setting the EPA or DEP standard will not cure 

this degradation, but will provide clear direction for all resource users to better understand the changes in our behavior 

necessary to restore the quality of our springs and rivers. 

Comment ID 2233-1.001.026 

Author Name: Kovach C. 

Organization: CF Industries 

11/19/2010 02:48 PM EST 2-4026
 
Chapter 2 - Comment Documents Springs and Clear Streams 

3. NO3-NO2 Springs and Clear Streams - Proposed 40 C.F.R. § 131.43(c)(3) 

3.1 The Criterion is Unnecessarily Low 

EPA did no independent analyses to confirm that 0.35 mg/l nitrate-nitrite is the appropriate number to use as a criterion 

for the inorganic and more biologically available form of nitrogen.[25] The agency simply proposed the same number 

that was under consideration by the Florida DEP. The State acknowledged that its proposed nitrate-nitrite criterion was 

conservative. Based upon a combination of field, laboratory and mesocosm studies, 0.35 mg/l was selected by the 

Florida DEP, although field studies suggested that ambient nitrate-nitrite could reach 0.441 mg/l before adverse 

biological effects (persistent excess biomass) are observed. Consequently, to the extent that a criterion is justified at all, 

the 0.44 mg/l nitrate-nitrite is a more appropriate number than the more conservative 0.35 mg/l derived by the Florida 

DEP and proposed by EPA. 

[25] The State's criterion was initially developed for spring boils and spring vents and later expanded to "clear streams" 

with color less than 40 platinum cobalt units (PCU). Consequently, it could be argued that the Florida DEP has also 

taken considerable scientific license in projecting its springs numbers upon Florida clear streams. 

Comment ID 2233-1.001.056 

Author Name: Kovach C. 

Organization: CF Industries 

6. The proposed criteria developed by the USEPA for clear streams are not based on a cause-effect relationship and 

therefore also are invalid; 

Comment ID 2233-1.001.084 

Author Name: Kovach C. 

Organization: CF Industries 

Comments on Spring Criteria- Proposed 40 C.F.R. § 131.43(c)(3) 

The USEPA essentially adopted the proposed FDEP proposal regarding nitrate-nitrate limits for springs. Differences of 

opinion regarding the calculation of the data used to compare to the criteria (median vs. geometric mean) were noted in 

FDEP's comments on the numeric criteria for springs (FDEP, 2010e). While we acknowledge the application of various 

scientific studies in support of these criteria, we believe the proposed criteria will only partly solve the eutrophication 

problems observed in springs. The nitrate criteria may apply to springs with algal impacts; we do not believe nitrate 

levels control macrophyte problems in these systems. 

Additionally, we question whether the application of a numeric nitrite-nitrate criterion for springs and spring runs will 

foster appropriate management actions. In other words, the nitrite-nitrate issue is a legacy watershed issue, and for the 

11/19/2010 02:48 PM EST 2-4027
 
Chapter 2 - Comment Documents Springs and Clear Streams 

most part, cannot be managed through the current regulatory constructs. 

We also question the validity of applying the nitrate criteria in the remaining Florida streams since it is not supported by 

a similar dataset as produced for springs. It is unclear that there is a suitable database that has demonstrated a direct 

cause and effect relationship in the clear stream systems, as should be the requirement for any numeric nutrient criteria 

promulgated. 

Response 

Comment IDs: 1770-1.001.046, 1771-1.001.056, 1772-1.001.050, 1773-1.001.051 

Response: EPA has finalized NO3+NO2 criteria for springs. EPA disagrees that the NO3+NO2 criteria are not based on sound 

science. EPA also disagrees with the comment that suggests the concentration of the criteria may be "overly conservative". EPA 

considered multiple lines of evidence when deriving a NO3+NO2 criterion value for springs. Studies that were used in this 

derivation ranged from highly controlled laboratory studies to analyses of field observations. Highly controlled laboratory 

experiments provide evidence of a causal linkage between increased NO3+NO2 concentrations and increase algal abundance. In 

the lab, abundance of two algal species relevant to Florida streams (Lyngba and Vaucheria) reached maximum values at 230 ug/L 

and 261 ug/L NO3 (see final rule TSD). 

Analyses of field observations provide estimates of relationships between algal abundance and nutrient concentrations in natural 

settings. Because these data are collected from the field, other environmental factors may influence estimated observed 

relationships between nitrate and algal responses. For example, as noted by several comments, abundance of Lyngba was not 

correlated with nitrate concentrations in one field study (Stevenson 2007). However, Lyngba abundance increased with increased 

nitrate concentration in controlled laboratory experiments. In general, analyses of field data were used only as a line of evidence in 

conjunction with controlled laboratory experiments, and therefore, uncertainty associated with effects of other environmental 

factors (e.g., turbidity, dissolved oxygen) that is inherent in analyses of field data is less important. All lines of evidence 

contributed to EPA’s overall understanding of the relevant stressor-response relationships and informed the final criteria derivation. 

EPA disagrees with comments that springs criteria derived using data from certain sites are not applicable across a broader region. 

The NO3+NO2 criterion value was derived from multiple lines of evidence, including laboratory studies and analyses of field data. 

The effects of local conditions on the relationships between nitrate and algal abundance can vary between different geographic 

locations because of the influence of other factors. However, laboratory studies indicating a strong response between nitrate 

concentration and algal abundance are relevant to all locations. Hence, EPA recognizes that the locations of the field studies used 

in deriving this criterion were limited. However, all of these analyses contribute to our overall understanding of the response of 

algae to nitrate enrichment, and the derived criterion value is appropriately protective. EPA does recognize that the relationships 

between increased NOx and nuisance algae can vary slightly between different springs, and in some locations, the criterion value 

may need to be altered. In these cases, the SSAC process provides a means of specifying the criterion value that is protective for a 

given location. 

EPA considers the NO3+NO2 criterion to be protective of the designated uses in springs and does not preclude in its final rule 

11/19/2010 02:48 PM EST 2-4028
 
Chapter 2 - Comment Documents Springs and Clear Streams 

scientifically defensible criteria developed in the future that may offer additional protections. 

Comment ID: 1777-2.001.030 

Response: EPA has finalized NO3+NO2 criteria for springs. With respect to where the criteria apply, EPA refers the commenter to 

the preamble and final rule for the definition of a spring. 

Comment ID: 1805-3.001.133 

Response: EPA also disagrees with the comment that suggests the concentration of the criteria may be "overly conservative". EPA 

considered multiple lines of evidence when deriving a NO3+NO2 criterion value for springs. Studies that were used in this 

derivation ranged from highly controlled laboratory studies to analyses of field observations. Highly controlled laboratory 

experiments provide evidence of a causal linkage between increased NO3+NO2 concentrations and increase algal abundance. In 

the lab, abundance of two algal species relevant to Florida streams (Lyngba and Vaucheria) reached maximum values at 230 ug/L 

and 261 ug/L NO3 (see final rule TSD). 

Analyses of field observations provide estimates of relationships between algal abundance and nutrient concentrations in natural 

settings. Because these data are collected from the field, other environmental factors may influence estimated observed 

relationships between nitrate and algal responses. For example, as noted by several comments, abundance of Lyngba was not 

correlated with nitrate concentrations in one field study (Stevenson 2007). However, Lyngba abundance increased with increased 

nitrate concentration in controlled laboratory experiments. In general, analyses of field data were used only as a line of evidence in 

conjunction with controlled laboratory experiments, and therefore, uncertainty associated with effects of other environmental 

factors (e.g., turbidity, dissolved oxygen) that is inherent in analyses of field data is less important. All lines of evidence 

contributed to EPA’s overall understanding of the relevant stressor-response relationships and informed the final criteria derivation. 

Comment ID: 0695.001.002 

Response: EPA disagrees with the comment that different criteria should apply in urban versus forest springs. Since groundwater 

is the source of spring water, the immediately surrounding land use has a weak effect on the nitrate levels in the spring. Hence, 

urban and forest springs that have been assigned the same designated use should have the same criterion value. 

Comment IDs: 1217-2.001.017, 1217-2.001.046, 1304-1.001.030, 1352-1.001.145, 1474-1.001.148, 1764-1.001.008, 2233­

1.001.026, 2233-1.001.084 

Response: EPA agrees with comments that springs criteria are not applicable to clear streams. EPA’s NO3+NO2 criteria only 

apply to springs in the final rule. EPA determined that the final TN and TP criteria applied to streams would provide sufficient 

11/19/2010 02:48 PM EST 2-4029
 
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protection of designated uses in clear streams. 

Comment IDs: 1352-1.001.075, 1352-1.001.131, 1352-1.001.134, 1352-1.001.135, 1352-1.001.141, 1355-2.001.009, 1355­

2.001.049 

Response: EPA agrees with comments that restate technical findings from the proposed rule. 

Comment ID: 1474-1.001.147 

Response: EPA agrees with the comment that the term “strong relationship” was not quantified. However, relationships between 

periphyton and nutrient concentrations in streams were observed, and these relationships contributed to a weight-of-evidence 

understanding of the effects of nutrients on algal abundance. 

Comment IDs: 1355-2.001.048, 1474-1.001.152, 1769-1.001.022, 2233-1.001.056, 1352-1.001.130, 1887-1.001.005 

Response: EPA agrees with comments that correlations observed in field observations do not demonstrate causation. However, 

EPA disagrees with comments that these correlations cannot be used to inform criterion values. EPA considered multiple lines of 

evidence when deriving a NO3+NO2 criterion value for springs. Studies that were used in this derivation ranged from highly 

controlled laboratory studies to analyses of field observations. Highly controlled laboratory experiments provide evidence of a 

causal linkage between increased NO3+NO2 concentrations and increase algal abundance. In the lab, abundance of two algal 

species relevant to Florida streams (Lyngba and Vaucheria) reached maximum values at 230 ug/L and 261 ug/L NO3 (see final rule 

TSD). 

Analyses of field observations provide estimates of relationships between algal abundance and nutrient concentrations in natural 

settings. Because these data are collected from the field, other environmental factors may influence estimated observed 

relationships between nitrate and algal responses. For example, as noted by several comments, abundance of Lyngba was not 

correlated with nitrate concentrations in one field study (Stevenson 2007). However, Lyngba abundance increased with increased 

nitrate concentration in controlled laboratory experiments. In general, analyses of field data were used only as a line of evidence in 

conjunction with controlled laboratory experiments, and therefore, uncertainty associated with effects of other environmental 

factors (e.g., turbidity, dissolved oxygen) that is inherent in analyses of field data is less important. All lines of evidence 

contributed to EPA’s overall understanding of the relevant stressor-response relationships and informed the final criteria derivation. 

Comment IDs: 1352-1.001.142, 1355-2.001.051, 1761-3.001.147, 1777-2.001.118, 1810-1.001.013, 2030-1.001.005, 2233­

1.001.026, 1464-1.001.012, 1464-2.001.033 

Response: EPA disagrees with comments suggesting that the NO3+NO2 criterion should be higher or lower than 0.35 mg/L. 

11/19/2010 02:48 PM EST 2-4030
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Selection of the final criterion value required that EPA weigh different types of evidence. The final criterion value of 0.35 mg/L is 

less than the value criterion value derived from field studies and greater than values observed from laboratory studies, and therefore 

balances uncertainty inherent in the translating ideal laboratory conditions to the field versus uncertainty inherent in estimating 

stressor-response relationships from field data. NOx concentrations of 0.23 mg/L support 90% of maximal growth of P. wollei in 

controlled laboratory studies, but in the field, the threshold concentration is likely higher because availability of ambient NOx can 

be limited by algal mat thickness and other environmental factors. Therefore, EPA selected a criterion value that is slightly higher 

than the laboratory value. Conversely, field studies indicate a range of thresholds centered around 0.44 mg/L. With field studies, 

uncertainty in the broad applicability of data collected from a particular set of sites, and uncertainty with regard to the precision of 

the sampling methods calls for a conservative approach to interpreting these values. Hence, EPA selected a value that is less than 

the thresholds estimated from field data. 

Comment IDs: 1304-1.001.030, 1887-1.001.006 

Response: EPA disagrees with comments that change point analysis was not an appropriate analysis to apply to this data. Change 

point analysis was applied to these data because these model forms (i.e., a step function for the response variable) accounted for 

more variability in the response variables than other methods (Niu 2007). EPA agrees with comments that uncertainty in estimated 

changepoints should be quantified. This uncertainty was quantified in the original proposal; confidence intervals for changepoints 

were estimated using bootstrap re-sampling (see final rule TSD). EPA disagrees with comments that multiple changepoints should 

be estimated. In this application EPA was interested in only the first changepoint, at which the response variable exhibited a strong 

change in value with respect to nutrient concentrations. 

Comment IDs: 1217-2.001.017, 1230.001.007, 1352-1.001.139, 1352-1.001.140, 1769-1.001.022, 1836.001.043, 1887-1.001.005 

Response: EPA disagrees with comments that springs criteria derived using data from certain sites are not applicable across a 

broader region. The NO3+NO2 criterion value was derived from multiple lines of evidence, including laboratory studies and 

analyses of field data. The effects of local conditions on the relationships between nitrate and algal abundance can vary between 

different geographic locations because of the influence of other factors. However, laboratory studies indicating a strong response 

between nitrate concentration and algal abundance are relevant to all locations. Hence, EPA recognizes that the locations of the 

field studies used in deriving this criterion were limited. However, all of these analyses contribute to our overall understanding of 

the response of algae to nitrate enrichment, and the derived criterion value is appropriately protective. EPA does recognize that the 

relationships between increased NOx and nuisance algae can vary slightly between different springs, and in some locations, the 

criterion value may need to be altered. In these cases, the SSAC process provides a means of specifying the criterion value that is 

protective for a given location. 

Comment IDs: 1352-1.001.128, 1352-1.001.129, 1464-2.001.033, 1791-1.001.001 

Response: EPA disagrees with comments that nutrient criteria should match historical nutrient concentrations in springs. EPA 

recognizes that historical nitrate concentrations are lower than the proposed criterion value. However, EPA’s obligation is to derive 

11/19/2010 02:48 PM EST 2-4031
 
Chapter 2 - Comment Documents Springs and Clear Streams 

criteria that are protective of designated uses, and restoration of historical nutrient concentrations may not be necessary for this 

goal. Analyses of laboratory and field stressor-response relationships indicate that the criterion value of 350 ug/L is protective of 

designated uses. 

Comment IDs: 1352-1.001.138, 1355-2.001.049, 2233-1.001.084 

Response: EPA agrees with comments that groundwater retention times are long and the timescale for management actions to take 

effect is long. EPA recognizes that groundwater sources for springs can reflect historical nutrient enrichment and that management 

actions would be expected to influence nutrient concentrations in springs only on long (e.g., decades) time scales. However, the 

specified criterion is protective of designated uses whether it is achieved in the short or long term. 

Comment IDs: 1362-1.001.005, 1431-1.001.032, 1474-1.001.011, 1474-1.001.151, 1474-1.001.154, 1346-1.001.010 

Response: EPA disagrees with comments that the criteria derivation method did not conclusively demonstrate protection of 

designated uses. Nuisance algae species have proliferated and are now out-competing and replacing SAV in springs and clear 

streams. As benthic algal mats accumulate, they kill beneficial SAV through direct smothering or indirectly through shading 

(Dennison and Abal 1999; Doyle and Smart 1998). Once the native SAV is displaced, other nonnative taxa such as Hydrilla 

verticillata (hydrilla) can re-colonize bare substrates, leading to other biological and ecological changes. For example, springs have 

become increasingly inhospitable to certain fish, snails, crayfish, turtles, and other animals that depend on the spring habitat. The 

loss of the native SAV, as well as the increased dominance of nuisance filamentous algae, results in community metabolism 

changes and disappearance of higher-order animals. This chain of events reflects the significant adverse structural and functional 

changes that have occurred in spring ecosystems. Hence, excessive growth of macroalgae is considered to constitute an imbalance 

of the natural biological communities and not in compliance with Florida’s narrative nutrient criteria. EPA expects that reductions 

of NOx concentrations to 0.35 mg/L will restore balance of natural biological communities in Florida springs. 

Comment IDs: 1464-1.001.012, 2045-1.001.002 

Response: After careful consideration and analysis of all relevant data for springs, EPA is finalizing a springs criterion of 0.35 mg/L 

not to be exceeded as an annual geometric mean not to be exceeded more than once in three years. EPA disagrees that compliance 

with the springs NO3+NO2 criterion should be based on monthly mean values. EPA found in its review of springs data and 

information that nitrate concentrations can be variable from month to month, and this intra-annual variability was not necessarily 

associated with impairment of the designated use. Therefore, to control for intra-annual variability, EPA chose to characterize the 

springs criteria over an annual basis. 

Comment IDs: 1352-1.001.074, 1352-1.001.143, 1355-2.001.051, 1887-1.001.007 

Response: EPA agrees with comments that backwatering events can influence water quality. However, field sampling protocols 

11/19/2010 02:48 PM EST 2-4032
 
Chapter 2 - Comment Documents Springs and Clear Streams 

specifying when and when not to collect water quality samples can control for this possibility. 

Comment ID: 1355-2.001.047 

Response: EPA agrees with the comment that phosphorus enrichment may contribute to observed algal abundance in springs. 

However, EPA did not find evidence to support a numeric nutrient criterion for phosphorus as it did for NO3+NO2 in Florida 

springs. 

Comment ID: 1645-1.001.021 

Response: EPA agrees with the comment that the MCL for nitrate is much higher than the proposed criterion value for nitrate in 

streams. The proposed criterion is intended to protect all designated uses, and the protective value for aquatic life use yielded the 

proposed value of 0.35 mg/L. 

Comment IDs: 0695.001.002, 1352-1.001.136, 1352-1.001.137, 1887-1.001.007 

Response: EPA agrees with comments that identifying appropriate management actions for controlling nitrate sources may be 

difficult. However, specifying management actions is beyond the scope of this rule, in which EPA is only specifying the 

concentrations in different waterbodies that protect designated uses. 

Comment ID: 1474-1.001.153 

Response: EPA agrees that different studies were conducted over different periods of time. With field data collected from a single 

visit, one generally assumes that the field measurements of nutrients and of algal characteristics provide an estimate of the longterm average conditions at a particular site. The accuracy of this estimate varies, depending on the inherent temporal variability of 

the factors that are measured, and this accuracy was taken into account when interpreting the data. The rapid periphyton data 

provided one line of evidence which, when combined with other lines of evidence derived from both laboratory and field studies, 

provided for a sound scientific understanding of the effects nitrate in springs and clear streams. 

Comment ID: 1474-2.001.006 

Response: Chapter 3 of the final rule TSD provides the technical justification for the derivation of the NO3+NO2 criterion for 

springs. 

Comment ID: 1839-1.001.003 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Response: EPA agrees with the comment that regulatory actions on nutrient enrichment are warranted. 

Comment IDs: 1839-1.001.004, 1839-1.001.005 

Response: EPA agrees that other factors, in addition to increases in nitrate concentration, can further explain patterns of algal 

accumulation observed in field data. These other factors may include changes in dissolved oxygen in groundwater and reductions 

in grazer abundance. However, clear linkages have been demonstrated between increased nutrients and increases in algal 

abundance in laboratory studies (see final rule TSD), and so reducing nutrient concentrations is a critical component in efforts to 

reduce algal abundance and protect designated uses in springs. 

EPA agrees that protection of downstream designated uses is an important rationale for setting criterion values. 

Comment ID: 1887-1.001.005 

Response: EPA disagrees that a modification procedure for springs criteria is necessary. The existing SSAC process provides a 

procedure for adjusting criterion values for a particular site. Sufficient data were not available in springs (as compared to lakes) to 

specify a range of criterion values within which a self-implementing criterion modification could operate. 

Comment IDs: 0915-1.001.010, 1311.001.009 

Response: EPA notes that the supplemental data cited in these comments was not provided, and so EPA cannot respond. 

III.D.3.Q.2 - REQUEST FOR COMMENT AND DATA ON PROPOSED 

APPROACH QUESTION 2 

Comment ID 0580.001.005 

Author Name: Browning D. 

Organization: 

Storm Water loaded with nitrates and other pollutants is discharged directly into the drinking water aquifer via Drainage 

Wells, and Sinkholes. 

Original comment letter contains additional information for springs and clear streams through a website link. See 

http://springsprotection.com/ for more information about nitrates and other pollutants in stormwater being discharged 

into aquifers. 

11/19/2010 02:48 PM EST 2-4034
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 0580.001.006 

Author Name: Browning D. 

Organization: 

To shift the attention away from the utilities problem of discharging directly into the pipes and sinkholes, FDEP has 

developed; 'The Springs Protection Initiative', funded by the State of Florida. Using what is knows as a "Narrative 

Standard", FDEP is able to make a judgement call based on observation as to the harm caused by the utility discharge 

of pollutants. Examples are the 28 Drainage Wells in Ocala Florida that discharge directly to Silver Springs. Often the 

city storm-sewer system discharges many times the level of 1.0 mg/l for nitrogen. 

Original comment letter contains additional information for springs and clear streams through a website link. See 

http://springsprotection.com/id2.html for more information about 28 Drainage Wells in Ocala Florida that discharge 

directly to Silver Springs. 

Comment ID 0585.001.003 

Author Name: Tomaski N. 

Organization: 

Please refer to the Florida Springs Task Force Report of 2000, called the Florida Springs Strategies for the Protection 

and Restoration. Also refer to the Wakiva Parkway and Protection Act of 2005 for useful information and strategies to 

follow. 

Original comment letter contains additional information regarding springs and clear streams in the Florida Springs Task 

Force Report of 2000 and the Wakiva Parkway and Protection Act of 2005. 

Comment ID 0946.001.002 

Author Name: Dickinson J. 

Organization: Forest Management Trust 

Original comment letter contains additional information as an attachment of recommendations of fertilizer rates for 

oranges from J. Dickenson. See original comment letter. 

Comment ID 1217-8.001.001 

11/19/2010 02:48 PM EST 2-4035
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Author Name: Voyles J. 

Organization: Mosaic Fertilizer LLC 

Original comment letter contains additional information as an attachment of the report, Springs, Spring Runs, and Clear 

Streams from Mosaic Fertilizer LLC. See original comment letter. 

Comment ID 1761-3.001.152 

Author Name: Merrill M. 

Organization: Hillsborough County 

III.D(3) Request for Comment and Data on Proposed Approach
 

Statement:
 

EPA is seeking additional, readily-available, pertinent data and information related to nutrient concentrations or nutrient
 

responses in springs and clear streams in Florida.
 

Comment:
 

We do not have any additional data to provide, but wish to reserve the opportunity to provide such data if and when it
 

becomes available.
 

Comment ID 1777-2.001.123 

Author Name: Blanchard B.
 

Organization: Florida Department of Transportation
 

III.D(3) Request for Comment and Data on Proposed Approach
 

Statement:
 

EPA is seeking additional, readily-available, pertinent data and information related to nutrient concentrations or nutrient
 

responses in springs and clear streams in Florida.
 

Comment:
 

We do not have any additional data to provide, but wish to reserve the opportunity to provide such data if and when it
 

becomes available.
 

11/19/2010 02:48 PM EST 2-4036
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1801-1.001.044 

Author Name: Green III K. 

Organization: St. Johns River Water Management District 

Original comment letter contains additional information as Attachment 2: Review of EPA-proposed numeric criteria for 

NOx in springs and clear streams in Florida. See original comment letter (pg. 55-67 of pdf). 

Comment ID 1805-3.001.138 

Author Name: Gallagher J. 

Organization: Pasco County 

III.D(3) Request for Comment and Data on Proposed Approach
 

Statement:
 

EPA is seeking additional, readily-available, pertinent data and information related to nutrient concentrations or nutrient
 

responses in springs and clear streams in Florida.
 

Comment:
 

We do not have any additional data to provide, but wish to reserve the opportunity to provide such data if and when it
 

becomes available.
 

Comment ID 1887-1.001.004 

Author Name: Manson D. 

Organization: Manson Law Group, P.A. on behalf of Nestle Water North America 

Original comment letter contains additional information in its reference list. 

Literature Cited 

Baker, M. E. and R. S. King . 2010. A new method for detecting and interpreting biodiversity and ecological community 

thresholds. Methods in Ecology and Evolution: 1: 25-37. 

Brenden, T. 0 ., L. Wang, and Z. Suo 2008. Quantitative identification of disturbance thresholds in support ofaquatic 

resource management. Environmental Management, 42 : 821-832. 

Brown, M. T., K. C. Reiss, M. 1. Cohen, J. M. Evans, P. W. Inglett, K. Sharma Inglett, K. R. Reddy, T. K. Frazer, C. A. 

11/19/2010 02:48 PM EST 2-4037
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Jacoby, E. J. Philips, R. L. Knight, S. K. Notestein, R. G. Hamann, and K. A. McKee. 2008. Summary and synthesis of 

the Available Literature on the effects of nutrients on spring organisms and systems. Prepared on behalf of Springs 

Initiative of the Florida Department of Environmental Protection by University of Florida Water Institute, Gainesville, 

Florida. 

Clements, W. H., D. M. Carlisle, L. A. Courtney, and E. A. Harrahy. 2002. Integrating observational and experimental 

approaches to demonstrate causation in stream biomonitoring studies. Environmental Toxicology and Chemistry, 21(6): 

11381146. 

Florida Geological Survey (FGS). 2004. Springs of Florida. Bulletin No. 66. Department of Environmental Protection I 

Florida Geological Survey. Tallahassee, FL. 

Katz, RG., H.D. Hornsby, J.F. Bohlke and M.F. Mokray. 1999. Sources and chronology of nitrate contamination in 

spring water, Suwannee River Basin, Florida. U. S. Geological Survey Water-Resources Investigations Report 99-4252. 

Reston, VA. 

Katz , RG., 1.K. Bohlke and H.D. Hornsby. 2001. Timescales for nitrate contamination of spring waters, northern 

Florida, USA. Chemical Geology 179:167-186. 

Katz, B.G., A.R. Chelette and T.R. Pratt. 2004. Use of chemical and isotopic tracers to assess nitrate contamination and 

ground-water age, Woodville Karst Plain, USA. Journal of Hydrology 289:36-61. 

King, R. S. and C. J. Richardson. 2003. Integrating bioassessment and ecological risk assessment: an approach to 

developing numerical water-quality criteria. Environmental Management, 31(6): 795-809. 

Phelps, G.G. 2004. Chemistry ofground water in the Silver Springs Basin, Florida, with an emphasis on nitrate. 

Scientific Investigations Report 2004-5144. Denver, CO. 

Qian, S. S., R. S. King, and C. J. Richardson. 2003 . Two statistical methods for the detection of environmental 

thresholds. Ecological Modeling 166: 87-97. 

Stevenson, RJ., A. Pinowska, A. Albertin, and J.O. Sickman. 2007. Ecological condition of algae and nutrients in Florida 

springs: The Synthesis Report. Prepared for the Florida Department of Environmental Protection. Tallahassee, FL. 58 

pp. 

Toth, D.J. 2003. Water quality and isotope concentrations from selected springs in the St. Johns River Water 

Management District. Technical Publication SJ2003- 1. Palatka, FL: S1. Johns River Water Management District. 

Comment ID 2399-14.001.001 

Author Name: Moore D. 

Organization: Southwest Florida Water Management District 

11/19/2010 02:48 PM EST 2-4038
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Original comment letter contains additional information as an attachment of Generalized Distribution and Concentration 

of Orthophosphate in Florida Streams prepared by United States Geological Survey in cooperation with the Bureau of 

Geology, Florida Department of Natural Resources. See original comment letter. 

This attachment is supplemental information to comment ID 1836. 

Comment ID 2399-9.001.001 

Author Name: Moore D.
 

Organization: Southwest Florida Water Management District
 

Original comment letter contains additional information as an attachment of Algal blooms and the nitrogen-enrichment 

hypothesis in Florida springs: evidence, alternatives, and adaptive management. See original comment letter. 

This attachment is supplemental information to comment ID 1836. 

Comment ID 2410-11.001.001 

Author Name: Long A. 

Organization: 

Original comment letter contains additional information as an attachment of a table of spring sampling data. See original 

comment letter. 

Supplemental Material for Comment ID 2030.2 

11/19/2010 02:48 PM EST 2-4039
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 2410-9.001.001 

Author Name: Long A. 

Organization: 

Original comment letter contains additional information as an attachment of spring sampling information in table form. 

See original comment letter. 

Supplemental Material for Comment ID 2030.2 

Comment ID 2420-1.001.001 

Author Name: Standridge K.
 

Organization: Florida Wildlife Federation, Sierra club, Audubon Society and Native Plant Society
 

Original comment letter contains additional information as an attachment of FDEP's Economic Impact of Selected 

Florida Springs on Surrounding Local Areas. See original comment letter. 

Supplemental Material for Comment ID 1919.2 

Comment ID 2420-2.001.001 

Author Name: Standridge K.
 

Organization: Florida Wildlife Federation, Sierra club, Audubon Society and Native Plant Society
 

Original comment letter contains additional information as an attachment from the 2008 Integrated Water Quality 

Assessment for Florida of Figure 9. Comparison of Recent and Historical Nitrate Concentrations in Florida Springs. See 

original comment letter. 

Supplemental Material for Comment ID 1919.2 

Response 

Comment IDs: 2420-2.001.001, 2420-1.001.001, 2410-11.001.001, 2410-9.001.001, 2399-9.001.001, 2399-14.001.001,1887­

1.001.004, 1761-3.001.152, 1805-3.001.138, 1801-1.001.044, 1777-2.001.123, 1217-8.001.001, 0946.001.002, 0585.001.003, 

0580.001.006, 0580.001.005 

Response: Some comments listed in this category are referenced information associated with the comments. EPA interpreted the 

11/19/2010 02:48 PM EST 2-4040
 
Chapter 2 - Comment Documents Springs and Clear Streams 

referenced information as supporting information (e.g., articles, journal papers, and reports) and did not provide a response to the 

referenced information. Where a comment indicated that EPA should consider a specific reference, EPA has provided a response. 

The responses to the referenced information are embedded in the responses to the comments to which it is associated. 

Some comments listed in this category are additional information that was submitted by commenters for consideration where the 

commenters did not provide any substantive comment or explanation of the pertinence of the additional information. During EPA's 

review of this information, the Agency could not provide a response because there was insufficient context or guidance in how it 

should consider the information. Where a comment directed EPA to consider additional information in a specific way, EPA has 

provided a response to comment where the specific additional information was referred to. 

III.D.3.Q.3 - REQUEST FOR COMMENT AND DATA ON PROPOSED 

APPROACH QUESTION 3 

Comment ID 1474-1.001.150 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

Spring environments are unique settings. Whether or how such environments have been impacted by nutrients is a very 

complicated matter. TFI recommends that EPA use its proposed criterion as an action level that would require individual 

assessments of springs to confirm whether impairment has occurred and whether nitrate-nitrite control will remedy the 

impairment. Further, EPA should allow the State to select the appropriate averaging period for demonstrating 

attainment of the criterion. 

In addition, data from these unique environments are not generally representative of all other streams, colored or clear. 

TFI recommends that EPA withdraw the spring run and clear stream nitrate-nitrite criteria as they have no objective 

scientific support. If EPA decides to finalize a nitrate-nitrite criterion for spring runs and clear streams, it must give the 

State the flexibility to apply this criterion only where the weight of the evidence shows that controlling nitrate-nitrite is 

necessary to protect designated uses. 

Comment ID 1761-3.001.153 

Author Name: Merrill M. 

Organization: Hillsborough County 

Statement: 

EPA is also soliciting views on other potential, scientifically sound approaches to deriving protective nitrate-nitrite 

criterion for springs and clear streams in Florida. 

Comment: 

11/19/2010 02:48 PM EST 2-4041
 
Chapter 2 - Comment Documents Springs and Clear Streams 

We do not have an alternative methodology to offer, but would reiterate our previous comment that it is not appropriate 

to apply TN and TP criteria to clear springs and clear streams on top of the proposed nitrate-nitrite criterion. In addition, 

water bodies should be managed such that the limiting nutrient, if there is one, is targeted for reduction. Targeting of the 

non-limiting nutrient will provide no benefit to the water body and will succeed only in wasting scarce restoration dollars 

that can be more beneficially used elsewhere. 

Comment ID 1777-2.001.124 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

Statement:
 

EPA is also soliciting views on other potential, scientifically sound approaches to deriving protective nitrate-nitrite
 

criterion for springs and clear streams in Florida.
 

Comment:
 

We do not have an alternative methodology to offer, but would reiterate our previous comment that it is not appropriate
 

to apply TN and TP criteria to clear springs and clear streams on top of the proposed nitrate-nitrite criterion. In addition,
 

water bodies should be managed such that the limiting nutrient, if there is one, is targeted for reduction. Targeting of the
 

non-limiting nutrient will provide no benefit to the water body and will succeed only in wasting scarce restoration dollars
 

that can be more beneficially used elsewhere.
 

Comment ID 1805-3.001.139 

Author Name: Gallagher J. 

Organization: Pasco County 

Statement: EPA is also soliciting views on other potential, scientifically sound approaches to deriving protective nitratenitrite criterion for springs and clear streams in Florida. 

Comment: We do not have an alternative methodology to offer, but would reiterate our previous comment that it is not 

appropriate to apply TN and TP criteria to clear springs and clear streams on top of the proposed nitrate-nitrite criterion. 

In addition, water bodies should be managed such that the limiting nutrient, if there is one, is targeted for reduction. 

Targeting of the non-limiting nutrient will provide no benefit to the water body and will succeed only in wasting scarce 

restoration dollars that can be more beneficially used elsewhere. 

Response 

Comment IDs: 1474-1.001.150, 1761-3.001.153, 1777-2.001.124, 1805-3.001.139 

11/19/2010 02:48 PM EST 2-4042
 
Chapter 2 - Comment Documents Springs and Clear Streams 

Response: EPA does not agree with the approach of using proposed springs criterion as an action level for additional water quality 

assessments. EPA intends its numeric nutrient criteria for Florida’s springs, and interprets the role of water quality standards in 

general, to provide protection of designated uses in a way that prevents significant adverse environmental impacts. Furthermore, 

EPA believes numeric nutrient criteria can serve as an important driver of immediate action s that would identify the sources of and 

remedies to water quality impairments. 

EPA disagrees with the comment that waterbodies should be managed based on the limiting nutrient. EPA acknowledges that one 

or both nutrients, nitrogen and phosphorus may be limiting in Florida springs. However, that limitation, if it occurs, may vary over 

time and space relative to one another. Thus, while it may be informative to consider nutrient limitation in deriving numeric 

nutrient criteria, EPA notes that it may be difficult to definitively identify the limiting nutrient at any given time or place in a spring.

 EPA also notes that employing this premise may not necessarily lead to nutrient criteria that are protective of designated uses, 

particularly in a spring system where export to a downstream water of a non-limiting nutrient may occur. This could lead to 

impairment of a downstream waterbody, which could have been prevented if nutrient criteria were not pre-conditioned on the basis 

of observed nutrient limitation. As such, EPA does not pre-condition numeric nutrient criteria development based on the limiting 

nutrient, nitrogen or phosphorus. 

EPA’s analysis of the data indicates that the proposed criterion value will maintain a balanced natural population of aquatic flora 

and fauna in Florida's springs. At certain unique sites, a site-specific criterion can be applied by implementing the SSAC process. 

EPA agrees with the comment that the springs criterion value for nitrate+nitrite does not need to be applied to clear streams because 

EPA determined that the final TN criteria for streams provided sufficient protection for clear streams. Both TN and TP criterion are 

specified in streams because both have been shown to influence biological communities and associated designated uses. 

EPA does not agree that the State should be allowed to specify the averaging period for demonstrating attainment of these criteria. 

The averaging period, the magnitude, and frequency of exceedance are all required to fully define the criterion. 

III.D.4 - ALTERNATIVE APPROACHES: NITRATE-NITRITE 

CRITERION FOR ALL WATERS AS AN INDEPENDENT CRITERION 

No Comments are Applicable to this Issue Category, and Thus No Response is Necessary. 

III.D.4.Q.1 - ALTERNATIVE APPROACHES: NITRATE-NITRITE 

CRITERION FOR ALL WATERS AS AN INDEPENDENT CRITERION 

QUESTION 1 

Comment ID 1217-2.001.023 

Author Name: Voyles J. 

Organization: Mosaic Fertilizer LLC 

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Chapter 2 - Comment Documents Springs and Clear Streams 

c. EPA Should Not Set A Nitrate/Nitrite Standard for All Waters 

EPA seeks comment on whether it should set a nitrate/nitrite standard for all waters and not just for springs and clear 

streams. See 75 Fed. Reg. at 4,211. Mosaic believes that such an approach is unwarranted. The TN criteria EPA 

proposes are sufficiently protective, and an additional nitrate/nitrite standard is unnecessary. Moreover, as is discussed 

above, application of the nitrate/nitrite standard to clear streams is not supported by the scientific evidence EPA has 

developed for this Rule. Absent compelling evidence that a nitrate/nitrite standard is required to protect designated 

uses, EPA should not attempt to establish such a standard for all waters. 

Comment ID 1362-1.001.009 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

EPA even suggests that it may apply nitrate-nitrite criterion to all waters in Florida to assist assessment and 

management and to "identify increasing trends." 75 Fed. Reg. at 4211. Under the Clean Water Act, water quality 

standards are established for the purpose of protecting designated uses, not to assist in assessment and management 

or to identify trends. EPA has no legal basis for establishing a nitrate-nitrite criterion for all Florida waters. 

Comment ID 1473-1.001.007 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

For springs and clear streams, EPA is proposing a nitrate-nitrite criterion that EPA asserts is based on experimental 

laboratory data and field evaluations that show algal growth in response to nitrate-nitrite concentrations. Again, EPA did 

not establish a defined impairment level or demonstrate a cause-and-effect relationship between the stressor and the 

response. Thus, EPA's proposed criterion for springs cannot be said to be necessary to protect spring and clear stream 

designated uses. EPA even suggests that it may apply nitrate-nitrite criterion to all waters in Florida to assist 

assessment and management and to "identify increasing trends." 75 Fed. Reg. at 4211. Under the Clean Water Act, 

water quality standards are established for the purpose of protecting designated uses, not to assist in assessment and 

management or to identify trends. EPA has no legal basis for establishing a nitrate-nitrite criterion for all Florida waters. 

Comment ID 1474-1.001.149 

Author Name: Herz W. 

Organization: The Fertilizer Institute 

EPA even suggests that it may apply nitrate-nitrite criterion to all waters in Florida to assist assessment and 

management and to "identify increasing trends." 75 Fed. Reg. at 4211. Under the Clean Water Act, water quality 

11/19/2010 02:48 PM EST 2-4044
 
Chapter 2 - Comment Documents Springs and Clear Streams 

standards are established for the purpose of protecting designated uses, not to assist in assessment and management 

or to identify trends. Thus, EPA has no basis for establishing a nitrate-nitrite criterion for Florida waters. 

Comment ID 1671-3.001.108 

Author Name: Brooks J. 

Organization: Florida Department of Environmental Protection 

EPA asked if the nitrate criterion should apply to all streams, regardless of color. In DEP's and EPA's analyses, there 

were no observed cause-effect relationships between nitrate and biological response in streams with color above 40 

PCU, meaning the nitrate criterion should apply only to clear streams (<40 PCU). The science does not support 

extending the nitrate criterion to clear streams. 

The DEP also recommends that EPA clarify the time frame for establishing the color of streams. DEP believes that the 

color should be based on the annual average (or longer-term) color of the stream, rather than the color of individual 

samples. 

Comment ID 1761-3.001.058 

Author Name: Merrill M. 

Organization: Hillsborough County 

3. EPA proposes an alternative that would apply the nitrate-nitrite criterion of 0.35 mg/l to all water bodies in the state ­

streams, lakes, and canals - in addition to the other numeric nutrient criteria that are proposed. Again, EPA has 

provided no supporting documentation to suggest that the addition of this requirement will result in improvement to the 

health of these water bodies. 

Comment ID 1761-3.001.154 

Author Name: Merrill M. 

Organization: Hillsborough County 

III.D(4) Alternative Approaches: Nitrate- Nitrite Criterion for All Waters as an Independent Criterion 

Statement: 

EPA is soliciting comment on the environmental benefits associated with deriving a nitrate-nitrite criterion for all waters 

covered by this proposal (i.e., all streams, lakes, and canals), in addition to the other proposed nutrient criteria for those 

water bodies. 

11/19/2010 02:48 PM EST 2-4045
 
 

 

Chapter 2 - Comment Documents Springs and Clear Streams 

Comment: 

The work used to support the development of the nitrate-nitrite criterion is specific to springs. EPA has not provided any 

supporting evidence to suggest that the work done for springs is applicable to other types of water bodies. In addition, 

water bodies must be managed for their limiting nutrient in order to avoid wasting resources reducing non-limiting 

nutrients with no benefit to the health of the water body. We are strongly opposed to the proposed "across-theboard" 

application of the nitrate-nitrite criterion to all water bodies in Florida. 

Comment ID 1777-2.001.031 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

3. EPA proposes an alternative that would apply the nitrate-nitrite criterion of 0.35 mg/l to all water bodies in the state 

- streams, lakes, and canals - in addition to the other numeric nutrient criteria that are proposed. Again, EPA has 

provided no supporting documentation to suggest that the addition of this requirement will result in improvement to the 

health of these water bodies. 

4. Water bodies should be managed to control the limiting nutrient where a limiting nutrient has been identified. 

Reductions to the loadings of the non-limiting nutrient will not improve the health of the water body, and will only force 

the expenditure of scarce resources for no benefit. 

Comment ID 1777-2.001.125 

Author Name: Blanchard B. 

Organization: Florida Department of Transportation 

III.D(4) Alternative Approaches: Nitrate- Nitrite Criterion for All Waters as an Independent Criterion
 

Statement:
 

EPA is soliciting comment on the environmental benefits associated with deriving a nitrate-nitrite criterion for all waters
 

covered by this proposal (i.e., all streams, lakes, and canals), in addition to the other proposed nutrient criteria for those
 

water bodies.
 

Comment:
 

The work used to support the development of the nitrate-nitrite criterion is specific to springs. EPA has not provided any
 

supporting evidence to suggest that the work done for springs is applicable to other types of water bodies. In addition,
 

water bodies must be managed for their limiting nutrient in order to avoid wasting resources reducing non-limiting
 

nutrients with no benefit to the health of the water body. We are strongly opposed to the proposed "across-the-board"
 

application of the nitrate-nitrite criterion to all water bodies in Florida.
 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID 1805-3.001.043 

Author Name: Gallagher J. 

Organization: Pasco County 

3. EPA proposes an alternative that would apply the nitrate-nitrite criterion of 0.35 mg/l to all water bodies in the state ­

streams, lakes, and canals - in addition to the other numeric nutrient criteria that are proposed. Again, EPA has 

provided no supporting documentation to suggest that the addition of this requirement will result in improvement to the 

health of these water bodies. 

Comment ID 1805-3.001.140 

Author Name: Gallagher J. 

Organization: Pasco County 

III.D(4) Alternative Approaches: Nitrate¬Nitrite Criterion for All Waters as an Independent Criterion
 

Statement:
 

EPA is soliciting comment on the environmental benefits associated with deriving a nitrate-nitrite criterion for all waters
 

covered by this proposal (i.e., all streams, lakes, and canals), in addition to the other proposed nutrient criteria for those
 

water bodies.
 

Comment:
 

The work used to support the development of the nitrate-nitrite criterion is specific to springs. EPA has not provided any
 

supporting evidence to suggest that the work done for springs is applicable to other types of water bodies. In addition,
 

water bodies must be managed for their limiting nutrient in order to avoid wasting resources reducing non-limiting
 

nutrients with no benefit to the health of the water body. We are strongly opposed to the proposed “across-the¬board”
 

application of the nitrate-nitrite criterion to all water bodies in Florida.
 

Response 

Comment IDs: 1217-2.001.023, 1362-1.001.009, 1473-1.001.007, 1474-1.001.149, 1671-3.001.108, 1761-3.001.058, 1761­

3.001.154, 1777-2.001.031, 1777-2.001.125, 1805-3.001.043, 1805-3.001.140 

Response: After careful consideration and an evaluation of comments received regarding this issue, EPA has decided not to finalize 

the springs NO3+NO2 criterion in clear streams. EPA considers the numeric nutrient criteria it is finalizing in this rule for streams, 

including clear streams, to be protective of designated uses and scientifically defensible. EPA concluded that Florida’s streams, 

including clear streams, will also be protected from excessive inorganic nitrogen pollution by the NO3+NO2 criteria, where there 

are springs in the streams’ upstream watershed. Both TN and TP criteria are required in streams because both have shown to 

influence biological communities and affect support for designated uses (see final rule TSD). 

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Chapter 2 - Comment Documents Springs and Clear Streams 

Comment ID: 1473-1.001.007 

Response: EPA agrees with comments that statistical correlations observed in field observations do not demonstrate causation. 

However, EPA disagrees with comments that these correlations cannot be used to inform criterion values. EPA considered multiple 

lines of evidence when deriving a NO3+NO2 criterion value for springs and clear streams. Studies that were used in this derivation 

ranged from highly controlled laboratory studies to analyses of field observations. Highly controlled laboratory experiments 

provide evidence of a causal linkage between increased nitrate concentrations and increase algal abundance. In the lab, abundance 

of two algal species relevant to Florida streams (Lyngba and Vaucheria) reached maximum values at 230ug/L and 261 ug/L NO3, 

which provided candidate criteria (see final rule TSD). 

As described in the final rule TSD, the field observations corroborate the results of these laboratory studies. Analyses of field 

observations provide estimates of relationships between algal abundance and nutrient concentrations in natural settings. Because 

these data are collected from the field, other environmental factors may influence estimated relationships between nitrate and algal 

responses. For example, as noted by several comments, abundance of Lyngba was not correlated with nitrate concentrations in one 

field study (Stevenson 2007). However, Lyngba abundance increased with increased nitrate concentration in controlled laboratory 

experiments. In general, analyses of field data were used only as a line of evidence in conjunction with controlled laboratory 

experiments, and therefore, uncertainty associated with effects of other environmental factors (e.g., turbidity, dissolved oxygen) that 

is inherent in analyses of field data is less important. All lines of evidence contributed to EPA’s overall understanding of the 

relevant stressor-response relationships and informed the final criteria derivation. 

Comment ID: 1671-3.001.108 

Response: EPA agrees that color observed in individual samples should not be used to establish the color for different streams. 

Long-term averages, or averages of all available color observations from a particular stream would provide the most appropriate 

measurement for classifying streams as colored or clear. However, EPA is not applying NO3+NO2 criteria to clear streams because 

EPA determined that the final TN and TP criteria provide sufficient protection for designated uses in these streams. Hence, the 

distinction between colored and clear streams is no longer relevant to criterion values for streams. 

Comment ID: 1474-1.001.149 

Response: EPA agrees that water quality standards are established for the purpose of protecting designated uses. EPA has finalized 

NO3+NO2 criteria for springs, and TN and TP criteria for streams that will protect the designated uses of these waterbodies. 

Comment ID: 1761-3.001.154 

Response: EPA disagrees with the comment that waterbodies should be managed based on the limiting nutrient. EPA 

11/19/2010 02:48 PM EST 2-4048
 
Chapter 2 - Comment Documents Springs and Clear Streams 

acknowledges that one or both nutrients, nitrogen and phosphorus may be limiting in Florida springs. However, that limitation, if it 

occurs, may vary over time and space relative to one another. Thus, while it may be informative to consider nutrient limitation in 

deriving numeric nutrient criteria, EPA notes that it may be difficult to definitively identify the limiting nutrient at any given time or 

place in a spring. EPA also notes that employing this premise may not necessarily lead to nutrient criteria that are protective of 

designated uses, particularly in a spring system where export to a downstream water of a non-limiting nutrient may occur. This 

could lead to impairment of a downstream waterbody, which could have been prevented if nutrient criteria were not pre-conditioned 

on the basis of observed nutrient limitation. As such, EPA does not pre-condition numeric nutrient criteria development based on 

the limiting nutrient, nitrogen or phosphorus. Furthermore, EPA did not find sufficient scientific evidence to support a numeric 

phosphorus criterion for Florida springs at this time. EPA notes that there was no evidence to suggest that phosphorus 

concentrations as springs are increasing over time, thus EPA considers the NO3+NO2 criteria to be protective of springs (see final 

rule TSD). 

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