PROPOSED 

TOTAL MAXIMUM DAILY LOAD (TMDL) 

For 

Dissolved Oxygen and Nutrients 

In The Everglades 

(WBIDs 3252A, 3252B, 3252C, 3260, 3263, 3265B) 

Hendry, Broward, Palm Beach, 

and Dade Counties, Florida 

Prepared by:

US EPA Region 4

61 Forsyth Street SW

Atlanta, Georgia 30303

September 2007

 
i 

TABLE OF CONTENTS 

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1 INTRODUCTION.............................................................................................................. 1

1.1 Purpose of Report............................................................................................................. 4 

1.2 Identification of Impaired Waterbodies ........................................................................... 5 

1.2.1 Everglades Agricultural Area....................................................................................... 5

1.2.2 Everglades Protection Area ....................................................................................... 13

2 STATEMENT OF WATER QUALITY PROBLEM................................................... 17

2.1 Impaired Waterbody Segments ...................................................................................... 18 

2.2 Pollutants of Concern.......................................................................................................... 18 

2.3 Source of Pollutants ....................................................................................................... 19 

3 WATER QUALITY STANDARDS ............................................................................... 22

3.1 Nutrient Criteria ............................................................................................................. 23 

3.1.1 Nutrient Criteria for Class III Waters........................................................................ 23

3.1.2 Nutrient Criteria for Class IV Waters ........................................................................ 23

3.2 Dissolved Oxygen Criteria............................................................................................. 23 

3.2.1 DO Criteria for Class IV Canals................................................................................ 23

3.2.2 DO Criteria for Class III Canals................................................................................ 24

3.2.3 DO Site Specific Alternative Criteria......................................................................... 24

4 TARGET IDENTIFICATION ....................................................................................... 26

4.1 Basis and Rationale For Phosphorus Targets................................................................. 26 

4.2 Phosphorus Target Development ................................................................................... 26 

4.2.1 Everglades Protection Area ....................................................................................... 26

4.2.2 Everglades Agricultural Area..................................................................................... 27

4.3 DO Target....................................................................................................................... 29 

5 WATER QUALITY RESULTS...................................................................................... 31

6 SOURCE ASSESSMENT ............................................................................................... 33
ii 

6.1 Background Loads.......................................................................................................... 33 

6.2 Permitted Point Sources ................................................................................................. 33 

6.2.1 Traditional Point Sources........................................................................................... 33

6.2.2 Stormwater Treatment Areas (STAs).......................................................................... 33

6.2.3 Municipal Separate Storm Sewer System Permittees................................................. 34

6.3 Nonpoint Sources ........................................................................................................... 35 

6.3.1 Agriculture.................................................................................................................. 36

7 TMDL ALLOCATION ................................................................................................... 37

7.1 Allocation....................................................................................................................... 37 

7.2 Load Allocation (LA)..................................................................................................... 37

7.3 Wasteload Allocation (WLA) ........................................................................................ 38 

7.4 Margin of Safety............................................................................................................. 38 

7.5 Seasonal Variability ....................................................................................................... 40 

8 TMDL IMPLEMENTATION ........................................................................................ 40

9 REFERENCES................................................................................................................. 41

APPENDIX B: Draft 2006 impairment determinations by FDEP........................................ 52

APPENDIX C: Indicators of phosphorus impairment in the EPA....................................... 54

APPENDIX D: Calculation of current water quality conditions .......................................... 56

APPENDIX E: PLOAD model, EMC values and results....................................................... 58

LIST OF TABLES 

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Table 1. Planning Unit and Basin Group for Impaired WBIDs..................................................... 4 

Table 2. Land use classification series for WBIDs. Data are for 1999......................................... 9 

Table 3. Water Year 2002-2006 Summary of Flows, TP Loads, and Average TP Concentrations into 

the Refuge at WBID 3252B (WCA-1 North Sector) (from SFWMD and FDEP, 2007). ... 14 

Table 4. Water Year 2002-2006 Summary of Flows, TP Loads, and Average TP Concentrations into 
iii 

EPA WBID 3265B (WCA-2 West Sector) (from SFWMD and FDEP, 2007). ................... 16 

Table 5. FDEP impairment determinations for Everglades WBIDs............................................ 18 

Table 6. Years with the lowest annual STA outflow TP concentration across STAs from 1995 to 

2006 (Pietro et al., 2007). ..................................................................................................... 28 

Table 7. Annual STA inflow TP loads based on PLR of 1.0 g/m2/year. ..................................... 29 

Table 8. WY2002 to WY 2006 TP concentration and load for EAA and EPA WBIDs.............. 32 

Table 9. Permitted Facilities Discharging into impaired EPA WBIDs. ...................................... 34 

Table 10. MS4 Permitees in the Drainage Basins of Impaired WBIDs....................................... 35 

Table 11. TMDL allocation for Total Phosphorus ...................................................................... 39 
iv 

ABBREVIATIONS

Ac-ft acre-feet 

AW FWMC Farm area-weighted flow-weighted mean concentration 

BMP Best Management Practices 

DO Dissolved Oxygen 

EAA Everglades Agricultural Area 

ECP Everglades Construction Project 

EMC Event Mean Concentration 

EPA Everglades Protection Area 

FAC Florida Administrative Code 

FDEP Florida Department of Environmental Protection 

FWMC Flow-weighted mean concentration 

HUC Hydrologic Unit Code 

LA Load Allocation 

Lb/day pounds per day 

MOS Margin of Safety 

MS4 Municipal Separate Storm Sewer Systems 

mt metric ton 

NPDES National Pollutant Discharge Elimination System 

OFW Outstanding Florida Water 

PLOAD Phosphorus Load model 

PLR phosphorus loading rate 

PLRG Pollutant Load Reduction Goal 

ppb parts per billion (micrograms per liter) 

R-EMAP Regional Environmental Monitoring and Assessment Project 

SFER South Florida Environmental Report 

SFWMD South Florida Water Management District 

SSAC Site-Specific Alternative Criterion 

STA Stormwater Treatment Area 

TBEL Technology-based Effluent Limit 

TMDL Total Maximum Daily Load 

TN Total Nitrogen 

TP Total Phosphorus 

USEPA United States Environmental Protection Agency 

WBID Water Body Identification 

WCA Water Conservation Area 

WLA Wasteload allocation 

WMD Water Management District 

WQBEL Water Quality Based Effluent Limit 

WY Water Year (May to April) 
v 

SUMMARY SHEET 

1. Florida 1998 303(d) Listed Waterbody Information 

WBID Segment Name Classification Constituent County HUC 

3265B* 

(3265F, 

3265H) 

Everglades Water 

Conservation Area 2A 

Southwest Perimeter 

3F 

Nutrients, DO, 

Fecal Coliform**, 

Cadmium** 

Broward, 

Palm Beach 03090202 

3252B 

Everglades Water 

Conservation Area 1 

North Sector (Arthur 

R. Marshall 

Loxahatchee National 

Wildlife Refuge 

3F 

Nutrients, DO, 

Fecal Coliform**, 

Total Suspended 

Solids** 

Palm Beach 03090202 

3263 S-7 Basin 3F Nutrients, DO, 

Turbidity** Palm Beach 03090202 

3260 S-8 Basin 3F Nutrients, DO Palm Beach, 

Hendry 03090202 

3252A Knight’s Farm Field 1 3F Nutrients Palm Beach 03090202 

3252C 

ACME North Sector 

(formerly Knight’s 

Farm Field 3) 

3F Nutrients Palm Beach 03090202 

* This WBID is included on the 1998 303(d) list and the 1998 Consent Decree. It was redrawn 

and renamed by FDEP in 2006. New names are in parentheses. 

** EPA has determined that TMDLs are not needed for these constituents, as water quality standards 

are currently achieved in the waterbody. 

2. Water Quality Standards: 

Class III: Waters. Recreation, propagation and maintenance of a healthy, wellbalanced population of fish and wildlife. Class IV Waters: Agricultural water supply. 

Dissolved Oxygen 

Applies to Class III canals within the Everglades Agricultural Area (EAA) and Everglades: 

DO (62-302.530(31)): Shall not be less than 5.0 mg/l. Normal daily and seasonal 

fluctuations above these levels shall be maintained. 

Applies to the marsh throughout the Everglades Protection Area (EPA): 

DO Site Specific Alternative Criterion (SSAC): 

DO concentration can vary with water temperature and time of day to reflect natural diurnal 

biological processes. 

Applies to Class IV canals within the EAA: 

DO (62-302.530(31)): Shall not average less than 4.0 mg/l in a 24-hour period and shall 

never be less than 3.0. Normal daily and seasonal fluctuations above these levels shall be 

maintained. 

Nutrients

Applies to Class IV canals within the EAA and Class III waters: 

Nutrients (62-302.530(48)(a)): The discharge of nutrients shall continue to be limited as 

needed to prevent violations of other standards contained in this chapter. Man induced 

nutrient enrichment (total nitrogen and total phosphorus) shall be considered degradation in 
vi 

relation to the provisions of Section 62-302.300, 62-302.700, and 62-4.242, FAC. 

Applies to Class III canals of the EAA and the EPA: 

 62-302.530(48)(b) In no case shall nutrient concentrations of a body of water be altered so 

as to cause an imbalance in natural populations of aquatic flora or fauna. 

Applies to the marsh throughout the Everglades Protection Area. 

 The TP criterion is a long-term geometric mean of 10 ppb, as specified in Section 62-

302.540, FAC. 

Natural Conditions (62-302.200(15)): Florida’s water quality standards provide a 

definition of natural background: 

“Natural Background” shall mean the condition of waters in the absence of man-induced 

alterations based on the best scientific information available to the Department. The 

establishment of natural background for an altered waterbody may be based upon a similar 

unaltered waterbody or on historical pre-alteration data. 

Florida’s water quality standards (62-302.300(15)) also provide that: 

Pollution which causes or contributes to new violations of water quality standards or to 

continuation of existing violations is harmful to the waters of this State and shall not be 

allowed. Waters having water quality below the criteria established for them shall be protected 

and enhanced. However, the Department shall not strive to abate natural conditions. 

3. TMDL Targets 

Nutrients: The TMDLs target Total Phosphorus (TP) because TP is the limiting nutrient 

for the Everglades. For the Everglades Protection Area WBIDs, the numeric TP criterion 

of 10 ppb geometric long-term average is applied at inflows as the equivalent annual 

maximum flow-weighted discharge limit of 16 ppb. For Everglades Agricultural Area 

(EAA) WBIDs, a TP concentration target is derived that is necessary to protect the 

downstream waters of the Everglades. This 100 ppb target is determined to be the 

concentration required at Stormwater Treatment Area (STA) inflows in order to result in 

the STA outflow of 16 ppb. The 100 ppb requirement is applied to Class III canals 

within the EAA. In addition, in order to protect Class III waters, this 100 ppb TP 

requirement is applied within the EAA to Class IV agricultural pumps at the point of 

discharge into Class III waters. The 100 ppb-based TMDL within the EAA should 

protect the designated use of the Class III canals within the EAA as well as diminish the 

contribution to water quality impairments in the downstream waters of the Everglades. 

Dissolved Oxygen: TMDLs for dissolved oxygen are addressed through controlling 

nutrients. All of the water conveyances within the EAA are artificial canals that were 

constructed for flood control and water supply purposes. Due to groundwater influence, 

it may not be possible to consistently meet the present statewide DO standard for Class 

IV waters (not less than 3.0 mg/L and 24-hour average not less than 4.0 mg/L), even 

after controlling pollutant loadings to those waters. For the Everglades marsh, 

improvement in phosphorus condition such that the waterbody no longer is impaired for 

nutrients should result in attainment of the DO SSAC. 
vii 

4. TMDL allocation for Total Phosphorus 

WBID Water 

Class 

TMDL1,2,3

(ppb) 

WLA 

(ppb) LA (ppb)2,3 MOS Percent Reduction4

Everglades Agricultural Area or ACME Improvement District 

Class III 100 0 100 Implicit 0% 

3263 (S-7) 

Class IV 100 0 100 (at inflow to 

Class III canal) Implicit 0% 

Class III 100 0 100 Implicit 0% 

3260 (S-8) 

Class IV 100 0 100 (at inflow to 

Class III canal) Implicit 0% 

Class III 100 0 100 Implicit 41% 

3252A (Knight’s 

Farm Field 1) Class IV 100 0 100 (at inflow to 

Class III canal) Implicit 41% 

3252C (ACME 

North Sector) Class III 100 0 100 Implicit 13% 

Everglades Protection Area 

3265B (3265F, 

3265H; WCA2A 

Southwest Sector) 

Class III 16 (see note 5) 16 Implicit 56% 

3252B (Refuge 

North Sector) Class III 16 (see note 5) 16 Implicit 82% 

Notes:

1. TMDL expressed as an annual load is calculated by multiplying 16 ppb times the annual flow and 

conversion factors. To express the TMDL as a daily load, the annual load is divided by 365 days per 

year. 

2. 100 ppb based on STA inflow need of 100 ppb to meet STA effluent of 16 ppb annual maximum. 

3. Allocation given to Class IV canals is necessary to protect the downstream Class III waters and 

should be implemented and monitored at the point of entry into Class III waters. 

4. Based on WY2002-2006 annual averages. 

5. Assumes all flow into this WBID is treated by STAs with NPDES permits. TMDL is to be 

applied on an annual basis by multiplying 16 ppb times the annual flow and conversion factors. 

5. Endangered Species (yes or blank): Yes 
viii 

6. USEPA Lead on TMDL (USEPA or blank): USEPA 

7. TMDL Considers Point Source, Nonpoint Source, or both: Both 

8. Major NPDES Discharges to EPA WBIDs 

9. MS4 Allocation. MS4 Permitees in the Drainage Basins of Impaired WBIDs 

County Permitee Permit ID Number MS4 Type TP target (ppb) 

Palm Beach Village of Wellington FLS000018 Phase I 100 

Note: The MS4 is responsible for controlling pollutant loads from the urban areas within its jurisdiction. 

Facility NPDES Permit Impacted 

WBID TP (ppb) 

STA-1E FL0304549 3252B 

STA-1W FL0177962-001 3252B 

16 

 applied at all 

inflows to 

WBID 

STA-2 FL0177946-001 3265B 

STA-3/4 FL0300195-001 3265B 

16 

 applied at all 

inflows to 

WBID 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

1

1 INTRODUCTION 

Section 303(d) of the Clean Water Act requires each state to list those waters within its boundaries 

for which technology based effluent limitations are not stringent enough to protect any water quality 

standard applicable to such waters. Listed waters are prioritized with respect to designated use 

classifications and the severity of pollution. In accordance with this prioritization, states are 

required to develop Total Maximum Daily Loads (TMDLs) for those water bodies that are not 

meeting water quality standards. The TMDL process establishes the allowable loadings of 

pollutants for a waterbody based on the relationship between pollution sources and in-stream water 

quality conditions, so that states can establish water quality based controls to reduce pollution from 

both point and non-point sources and restore and maintain the quality of their water resources 

(United States Environmental Protection Agency [USEPA], 1991). The TMDLs described in this 

report are being proposed pursuant to USEPA commitments in the 1998 Consent Decree in the 

Florida TMDL lawsuit (Florida Wildlife Federation, et al. v. Carol Browner, et al., Civil Action No. 

4: 98CV356-WS, 1998). 

The Florida Department of Environmental Protection (FDEP) developed a statewide, watershedbased approach to water resource management. Under the watershed management approach, water 

resources are managed on the basis of natural boundaries, such as river basins, rather than political 

boundaries. The state’s 52 basins are divided into 5 groups. Water quality is assessed in each group 

on a rotating five-year cycle. The Everglades Basin is located in group 5. FDEP established five 

water management districts (WMD) responsible for managing groundwater and surface water 

supplies in the counties encompassing the districts. Waters within the Everglades region that are 

addressed in this TMDL report are managed through the South Florida Water Management District 

(SFWMD). 

For the purpose of planning and management, the WMDs divided the districts into planning units 

defined as either an individual primary tributary basin or a group of adjacent primary tributary 

basins with similar characteristics. These planning units contain smaller, hydrological based units 

called drainage basins, which are further divided into “water segments”. Each segment is assigned a 

unique Waterbody IDentification (WBID) number. A water segment usually contains only one 

unique waterbody type (lake, canal, etc.). 

The locations of WBIDs in the Everglades are shown in Figure 1. The WBIDs that have nutrient 

TMDLs due September 30, 2007 as required by the Consent Decree are shown in Figure 2. This 

TMDL report addresses only those Everglades TMDLs that are due by September 30, 2007. 

The TMDLs are based on current available information. These TMDLs can be revised in the future, 

as the science and knowledge of the Everglades ecosystem improves. Any significant changes to the 

TMDLs will be required to go through the public process. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

2

Figure 1. Location of Everglades WBIDs (from SFWMD and FDEP, 2007). 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

3

Figure 2. Due dates required in the 1998 Consent Decree for nutrient TMDLs in the 

Everglades. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

4

1.1 Purpose of Report 

This document presents TMDLs for pollutants contributing to 1998 listed impairments (nutrients and 

Dissolved Oxygen (DO)) in the Everglades Protection Area (EPA) or the Everglades Agricultural 

Area (EAA). These areas were identified by FDEP in 1998 as impaired by nutrients or DO. In 2005 

FDEP revisited the impairment issue and again determined in their draft verified list that these areas 

are impaired for nutrients and DO (see Table 1). Because phosphorus is the limiting nutrient in the 

Everglades, it is the nutrient targeted in these TMDLs. Pollutant load reductions to Total 

Phosphorus (TP) should result in reduced nutrient loadings and ultimately achieve the designated 

use and not contribute to waterbody impairment. 

Table 1. Planning Unit and Basin Group for Impaired WBIDs 

WBID Segment Name Planning Unit Basin Group 

3265B* 

(3265F, 

3265H) 

Everglades Water 

Conservation Area 2A 

Southwest Perimeter 

Everglades Water 

Conservation Area 2 

5 

3252B 

Everglades Water 

Conservation Area 1 

North Sector (Arthur 

R. Marshall 

Loxahatchee National 

Wildlife Refuge) 

Everglades Water 

Conservation Area 1 

5 

3263 S-7 Basin Everglades Agricultural Area 5 

3260 S-8 Basin Everglades Agricultural Area 5 

3252A Knight’s Farm Field 1 Everglades Agricultural Area 5 

3252C* 

ACME North Sector 

(formerly Knights 

Farm Field 3) 

Everglades Water 

Conservation Area 1 

5 

* This WBID is included on the 1998 303(d) list and the Consent Decree. It was redrawn and 

renamed by FDEP in 2006. New names are in parentheses. 

 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

5

1.2 Identification of Impaired Waterbodies 

1.2.1 Everglades Agricultural Area 

The EAA is located on the southern tip of Lake Okeechobee and is one of the most productive 

agricultural regions in the State. Over 505,000 acres of the EAA are under production with sugar 

cane that accounts for over 80 percent of total crop coverage. Farmers also grow vegetables, sod, 

and rice during the winter months. Several major public canals (Miami, West Palm Beach, 

Hillsboro, and North New River) had been built by the 1920’s to drain and irrigate the EAA. These 

canals underwent major renovations and became part of the Central and Southern Florida Project 

(C&SF Project). These canals are Class III waters (see section 3). They are included on the 1998 

303(d) list as impaired for nutrients and DO. 

Florida’s 1994 Everglades Forever Act (EFA) required EAA landowners to reduce the total 

phosphorus in the runoff from their land by 25 percent basin-wide (Rule 40E-63). The green labels 

in Figures 3, 4, 6 and 8 identify the specific farm basins permitted to discharge under this rule. 

Landowners are implementing Best Management Practices (BMPs) to manage water, sediments, and 

nutrients that balance water quality improvements and agricultural productivity. From water year 

1996 to 2006 EAA Basin reductions were better than the 25% annual reduction required by the EFA. 

There are three WBIDs in the EAA that are included on the 1998 303(d) list as impaired for 

nutrients and DO that have TMDLs due by September, 30, 2007 as required by the 1998 Consent 

Decree: WBID 3260 (S-8 Basin); 3263 (S-7 Basin); and 3252A (Knight’s Farm Field 1) (Figures 2 

and 3). Land cover for all of these WBIDs is predominately agriculture (Table 2). All of these 

WBIDs drain into Stormwater Treatment Areas (STAs, wetlands constructed and managed to 

remove phosphorus from stormwater) which discharge into the downstream Everglades Protection 

Area (EPA). The EAA WBID delineations were drawn by FDEP in the 1980s. They do not 

accurately reflect current farm basins or drainages (Figures 3 to 9). 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

6

Figure 3. Location of WBIDs within the EAA (from SFWMD). WBIDs outlined in orange are 

the subject of this report. Black lines delineate farm basins. Green labels indicate permits 

under Florida EAA BMP Rule (Chapter 40E-63 F.A.C.). 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

7

1.2.1.1 WBID 3263 

WBID 3263 (S-7 basin) is in Palm Beach County within the EAA and is about 51,480 acres in area 

(Figures 4 and 5). There are three C & SF Project canals in the basin: the North New River Canal, 

the L-6 borrow canal and the L-5 borrow canal. The North New River Canal connects Lake 

Okeechobee to Everglades Water Conservation Areas (WCAs) 2 and 3. The connection to WCA2 is 

by the S-7 pump station, and the connection to WCA3 is by the S-150 pump. Project control 

structures that affect flow in the S-7 basin include S-7, S-2 (connects the North New River canal to 

Lake Okeechobee), S-150, and S-351 (a gated spillway on Lake Okeechobee) (Cooper 1989). Most 

of the farm discharges within this WBID are treated by STA 3/4 prior to discharge into the EPA. 

The discharges from about 1000 acres in the northeast corner are treated by STA 2, and the 

discharges from about 5800 acres in the southwest corner are discharged westward to the Miami 

Canal. Land cover in the S-7 basin is almost entirely agriculture (95%, Table 2). Water, wetlands 

and forest account for only about 2% of the land use. There are only 30 acres of urban or residential 

land. The basin also includes the future 8600 acre Compartment B STA expansion, projected for 

2010. There are 12 private pumps that discharge stormwater from agricultural land into the North 

New River Canal (Figure 4). The North New River Canal is designated as Class III water 

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

wildlife), while the smaller canals in agricultural lands that have been constructed and managed by 

private interests are all Class IV canals (agricultural water supply). There are no NPDES permitted 

facilities within this WBID.

Figure 4. WBID 3263, S-7 basin (from SFWMD). Black lines delineate farm basins. 

Green labels indicate permits under Florida EAA BMP Rule (Chapter 40E-63 F.A.C.). 
Copyrighted page/s removed. Copyrighted material is not available in 

Regulations.gov since it may not be reproduced without consent of 

the copyright holder. 

Contact the EPA Docket Center’s Public Reading Room to view 

or receive a copy of this document. 

Requests for copies may be made as follows: 

In person/writing: 

Environmental Protection Agency, Docket Center 

1301 Constitution Ave NW, 2822T, Room 3334 

Washington, DC. 20004 

Telephone: 

202-566-1744 

Fax: 

202-566- 9744 

Email: 

docket-customerservice@epa.gov 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

9

Table 2. Land use classification series for WBIDs. Data are for 1999. 

WBID 

Urban & 

Residential 

(1100-1390) 

Commercial, 

Industrial, 

Public (1400, 

1500, 1700, 

1800,1900) 

Agriculture 

(2000) 

Rangeland

(3000) 

Forest 

(4000) 

Water 

 (5000) 

Wetlands

(6000) 

Barren & 

Extractive 

(1600, 

7000) 

Tra

& 

3252A 0 167 21,562 179 0 326 68 98 

3252B 0 0 0 0 0 296 17,364 65 

3252C 3,169 1,602 1,885 998 81 554 230 55 

3260 0 0 55,787 29 0 344 27,047 709 3263 30 499 48,865 97 226 387 270 531 

3265F 0 0 0 0 0 144 7,411 113 

3265H 0 0 0 0 0 143 58,876 68 

WBID 

Urban & 

Residential 

(1100-1390) 

Commercial, 

Industrial, 

Public (1400, 

1500, 1700, 

1800, 1900) 

Agriculture 

(2000) 

Rangeland 

(3000) 

Forest 

(4000) 

Water 

 (5000) 

Wetlands

(6000) 

Barren & 

Extractive 

(1600, 

7000) 

Tra

& 

3252A 0% 0% 97% 1% 0% 1% 0% 0% 

3252B 0% 0% 0% 0% 0% 2% 98% 0% 

3252C 36% 18% 21% 11% 1% 6% 3% 1% 

3260 0% 0% 66% 0% 0% 0% 32% 1% 3263 0% 1% 95% 0% 0% 1% 1% 1% 

3265F 0% 0% 0% 0% 0% 2% 93% 1% 

3265H 0% 0% 0% 0% 0% 0% 100% 0% 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

10 

1.2.1.2 WBID 3260 

WBID 3260 (S-8 basin) encompasses 84,431 acres within the EAA and is located in Hendry and 

Palm Beach Counties (Figures 5 and 6). There are two C&SF Project canals in the basin: the Miami 

Canal and the L-4 Borrow Canal. The Miami Canal connects Lake Okeechobee to Everglades WCA 

3A. The connection to WCA 3A is by the S-8 pump station, and the connection to Lake Okeechobee 

is by the S-3 pump. Project control structures that affect flow in the S-8 basin include S-3, S-8, S354 (a gated spillway on Lake Okeechobee), and G-88 (a culvert at the intersection of L-3 and L-4 in 

northwestern WCA3A) (Cooper 1989). Stormwater from this WBID is treated in STA3/4 prior to 

discharge into the EPA. Land cover in the S-8 basin is primarily agriculture (66%, Table 2), 

although the basin also includes the Rotenberger Wildlife Management Area (a portion of 

Everglades managed by the State of Florida), and the future STA expansion (Compartment C, 8185 

acres). These wetlands areas account for 32% of the basin. Several private pumps discharge 

stormwater from agricultural land toward or into the Miami Canal (Figure 6). The Miami and L-4 

canals are designated as Class III waters, while smaller canals within the WBID are Class IV canals 

that drain agricultural lands. There are no NPDES permitted facilities within this WBID. 

Figure 6. WBID 3260, S-8 basin (from SFWMD). Black lines delineate farm basins and 

green labels are permits under Florida EAA BMP Rule (Chapter 40E-63 F.A.C.). 
Copyrighted page/s removed. Copyrighted material is not available in 

Regulations.gov since it may not be reproduced without consent of 

the copyright holder. 

Contact the EPA Docket Center’s Public Reading Room to view 

or receive a copy of this document. 

Requests for copies may be made as follows: 

In person/writing: 

Environmental Protection Agency, Docket Center 

1301 Constitution Ave NW, 2822T, Room 3334 

Washington, DC. 20004 

Telephone: 

202-566-1744 

Fax: 

202-566- 9744 

Email: 

docket-customerservice@epa.gov 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

12 

Figure 8. WBID 3252A, Knight’s Farm Field 1 (from SFWMD). Black lines delineate 

farm basins. Green labels indicate permits under Florida EAA BMP Rule (Chapter 40E63 F.A.C.). 

1.2.1.4 WBID 3252C 

WBID 3252C (ACME Basin North Sector) is about 8813 acres to the east of the Refuge. Land use 

in this WBID is a mix of primarily urban and residential (36%), agriculture (21%), and commercial 

and industrial (18%). Stormwater from this WBID is treated in STA 1E prior to discharge into the 

Refuge. This basin includes the Village of Wellington, which has a MS4 permit (FLS000018). 

There are no continuous discharge municipal or industrial NPDES permitted facilities within this 

WBID. 
Copyrighted page/s removed. Copyrighted material is not available in 

Regulations.gov since it may not be reproduced without consent of 

the copyright holder. 

Contact the EPA Docket Center’s Public Reading Room to view 

or receive a copy of this document. 

Requests for copies may be made as follows: 

In person/writing: 

Environmental Protection Agency, Docket Center 

1301 Constitution Ave NW, 2822T, Room 3334 

Washington, DC. 20004 

Telephone: 

202-566-1744 

Fax: 

202-566- 9744 

Email: 

docket-customerservice@epa.gov 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

14 

may be diverted around the STAs (via the G300 and G301 structures) into the Refuge. Annual flow, 

total phosphorus loads, and flow-weighted mean TP concentrations at structures discharging into the 

Refuge at WBID 3252B are summarized in Table 3 for the most recent five water years (WY2002-

WY2006). 

All water discharged into the Refuge in this WBID is to be treated by STA 1E or STA 1W. These 

STAs have NPDES permits (FL0304549 and FL0177962-001, respectively). The STA1W permit 

predates Florida’s 2005 adoption of the 10 ppb numeric TP criterion for the Everglades, and as such 

it does not reflect current water quality standards, nor does it contain revised discharge limits. FDEP 

has stated that they intend to reissue this permit to reflect the 10 ppb criterion, with appropriate 

discharge limits. A wasteload allocation for these permits is included in this TMDL document. 

Table 3. Water Year 2002-2006 Summary of Flows, TP Loads, and Average TP Concentrations into the Refuge at 

WBID 3252B (WCA-1 North Sector) (from SFWMD and FDEP, 2007). 

Year Parameter G300+G301

untreated 

G251 STA 

1W outflow 

G310 STA 

1W outflow 

S362 STA 

1E outflow 

WY 2002 Flow (1000 ac-ft) 11 7 261 

 TP Load (mt) 1.6 0.17 12.0 

 FWMC (ppb) 118.3 19.8 37.3 

WY 2003 Flow (1000 ac-ft) 10 97 499 

 TP Load (mt) 2.5 5.5 33.4 

 FWMC (ppb) 201.9 44.1 54.2 

WY 2004 Flow (1000 ac-ft) 17 55 243 

 TP Load (mt) 3.1 3.0 14.1 

 FWMC (ppb) 147.9 44.2 46.9 

WY 2005 Flow (1000 ac-ft) 69.1 62.85 320.5 15.9 

 TP Load (mt) 27.0 7.8 38.7 7.6 

FWMC (ppb) 317.1 100.4 97.8 387.3 

WY 2006 Flow (1000 ac-ft) 46.8 34.2 103.7 40.5 

 TP Load (mt) 14.0 4.5 14.7 7.3 

 FWMC (ppb) 242.5 107.4 115.1 145.7 

FWMC = Flow-Weighted Mean Concentration. WY2002 = May 2001 to April 2002. 

There was a marked increase in TP concentration in WY 2005 and 2006 in the untreated discharge 

from G-300 and G-301, as well as in the treated discharge from STA 1W. The increase in flows at 

the G300 + G301 diversion structures seen in WY 2005 and 2006 is due to decreased capacity in 

STA-1W due to hurricane damage which occurred in 2004 and STA enhancement construction 

activities. The decreased capacity in STA-1W, coupled with the partial capacity in the newly 

constructed STA-1E, resulted in the need for increased diversion at the G300 and G301 structures. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

15 

1.2.2.2 WBID 3265B (WCA-2A Southwest Perimeter) 

WBID 3265B encompasses 11,201 acres of Everglades Water Conservation Area 2A (Figure 2). 

This WBID is entirely Everglades marsh or canals. During 2006 this WBID was subdivided into 

WBIDs 3265F and a small portion of 3265H (Figures 1 and 2, Appendix B). WBID 3265B receives 

surface water discharges from the S-7 structure and a portion of STA-2 (G335) via a 3,400 foot gap 

in the L-6 levee. Additionally, water may flow into 3265B through sheet flow from upstream areas 

of the unimpacted (unimpaired) WBID 3265D. STA-2 receives inflow waters from both the S-6 

basin, WBID 3252A, and STA-1W conveyed via the L-7 canal. The S-7 structure discharges water 

from the S-7 basin including water treated by STA-3/4. Annual flow, total phosphorus loads, and 

flow-weighted mean TP concentrations at structures discharging to WBID 3265B are summarized in 

Table 3 for the most recent five water years (2002-2006). The summary for S7 was divided into preand post-STA 3/4 periods to account for the phosphorus removal provided by the STA after 

September 3, 2004. TP concentrations at S-7 improved after STA 3/4 began discharging. 

All water discharged into WBID 3265B is to be treated by STA 2 or STA 3/4. These STAs have 

NPDES permits (FL0177946-001 and FL0300195, respectively). The STA 2 permit was issued in 

September of 2007. It includes the 10 ppb criterion and a technology-based effluent limit (TBEL) 

applied to the discharge that varies from 22 ppb to 39 ppb, depending upon the phosphorus loading 

rate (grams P per square meter of STA per year) to the STA and the number of flow-ways in 

operation (Goforth et al. 2007a). The present STA 3/4 permit predates Florida’s adoption of the 10 

ppb numeric TP criterion for the Everglades, and as such it does not reflect current water quality 

standards, nor does it contain revised discharge limits. FDEP has stated that they intend to reissue 

this permit to reflect the 10 ppb criterion, with appropriate discharge limits. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

16 

Table 4. Water Year 2002-2006 Summary of Flows, TP Loads, and Average TP Concentrations into EPA WBID 

3265B (WCA-2 West Sector) (from SFWMD and FDEP, 2007). 

Year Parameter G335* 

STA 2 outflow 

S7 

(pre 9/3/04) 

S7 

(post 9/3/04, 

 from STA3/4) 

WY 2002 Flow (1000 ac-ft) 241 98 

 TP Load (mt) 4.9 5.8 

 FWMC (ppb) 16.5 47.8 

WY 2003 Flow (1000 ac-ft) 308 143 

 TP Load (mt) 6.6 9.6 

 FWMC (ppb) 17.4 54.5 

WY 2004 Flow (1000 ac-ft) 285 156 

 TP Load (mt) 5.0 8.6 

 FWMC (ppb) 14.3 44.5 

WY 2005 Flow (1000 ac-ft) 371 132.9 176.8 

 TP Load (mt) 9.2 3.4 2.6 

 FWMC (ppb) 20.1 20.8 11.8 

WY 2006 Flow (1000 ac-ft) 322.3 456.7 

 TP Load (mt) 8.2 10.8 

 FWMC (ppb) 20.7 19.2 

*Only a portion of the water discharged from G335 immediately effects WBID 3265B; i.e., the 

portion of water that is conveyed to south. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

17 

2 STATEMENT OF WATER QUALITY PROBLEM 

Section 303(d) of the Clean Water Act requires states to submit to the USEPA lists of waters that are 

not fully meeting their applicable water quality standards. FDEP has developed such lists, 

commonly referred to as § 303(d) lists, since 1992. As part of that process, FDEP included portions 

of the Everglades and the EAA on their 1998 § 303(d) list as impaired by excess nutrients or 

depressed dissolved oxygen. During 2006 FDEP revisited these determinations and found that the 

waters are still impaired (Appendices A and B). 

About one-half of the 4000-square mile pre-drainage Everglades has been drained and converted to 

agricultural or urban land uses. The remaining components of the historical Everglades have been 

impacted by hydrologic alterations and by the introduction of excessive levels of nutrients, which 

have resulted in the ecological degradation of the system. The Everglades is naturally an 

oligotrophic ecosystem that evolved in response to low ambient concentrations of nutrients and 

seasonally fluctuating water levels. Prior to the creation of canals, nitrogen and phosphorus were 

primarily supplied to the Everglades in low concentrations in surface water sheet flow. The 

historical system was phosphorus limited, with ambient phosphorus concentrations in unimpacted 

areas generally less than 10 ppb at interior marsh sites. 

The introduction of excess phosphorus to the Everglades has resulted in ecological changes over 

large areas of Everglades marsh. These changes are caused by cultural eutrophication, which is an 

increase in the supply of nutrients available in the marsh. The increase in nutrients has resulted in 

documented impacts to several trophic levels of aquatic life —including microbial, periphyton, 

macrophyte, invertebrate, and vertebrate communities—that constitute exceedances of the FDEP’s 

Class III narrative nutrient criterion (Section 62-302.530, F.A.C.). 

The excessive levels of phosphorus have also caused exceedances of the FDEP’s Class III SSAC for 

DO in the EPA. Nutrient enrichment typically produces a variety of system changes that ultimately 

result in a depressed oxygen regime in the water column. The Everglades is a highly phosphorus 

limited system, and as phosphorus levels increase, productivity increases, as does the accumulation 

of organic matter in the water and sediments (i.e., increased biochemical oxygen demand [BOD] and 

sediment oxygen demand [SOD]). This increased demand for oxygen results in greater oxygen 

consumption in both the water column and sediments. 

In addition to an altered community metabolism, changes in vegetation occur in response to 

eutrophication. As the degree (intensity or duration) of eutrophication increases, the open water 

slough communities are invaded by cattail (Typha) and other emergent vegetation (Rutchey and 

Vilchek, 1994; McCormick et al., 1999). The loss of the open water slough community and the 

shading (reduced light penetration) resulting from the increased growth of floating and emergent 

vegetation reduce the photosynthetic production of oxygen in the water column. Ultimately, the 

phosphorus enrichment results in an imbalance in the oxygen sources and sinks by increasing the 

demand for oxygen and reducing photosynthetic oxygen production. Therefore, the diel DO curves 

for phosphorus-enriched areas are characterized by overall lower DO levels and dampened diel 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

18 

fluctuations (Weaver, 2004). Several segments of the EPA are identified on the FDEP’s 2006 draft 

Verified List of Group 5 waterbodies as not meeting the Class III designated use due to nutrient 

impairment (Appendices A and B). Such impairment is based on technical evaluations performed by 

the FDEP, as set forth in numerous FDEP technical documents.1

2.1 Impaired Waterbody Segments 

The impaired Everglades segments that have TMDLs due in 2007 are listed in Table 5 and shown in 

Figure 2. FDEP determinations for impairment are included in Appendices A and B, and are based 

on information reported on the 1998 303(d) list. Initial impairment determinations made by FDEP 

during 2006 for Group 5 waters are also shown. Phosphorus-impacted areas are based on water 

phosphorus and soil phosphorus. Florida’s Everglades TP criterion rule defines impacted as where 

soil TP exceeds 500 milligrams TP per kilogram of soil. Cattail also can be an indicator of 

phosphorus enrichment (Appendix C). 

Table 5. FDEP impairment determinations for Everglades WBIDs.

Segments (WBIDs) Impaired for 

Nutrients Impaired for DO 

1998 2006 draft 1998 2006 draft 

S-7 Basin (3263) Yes Not assessed Yes Yes 

S-8 Basin (3260) Yes Not assessed Yes Potentially Impaired 

Knight’s Farm Field 1 

(3252A) Yes Not assessed No Insufficient Data 

ACME North Sector 

(3252C) Yes Not assessed No Yes 

WCA-1 North Sector 

(3252B) Yes Yes Yes Insufficient Data 

WCA-2 Southwest 

Perimeter (3265B) Yes Yes Yes Insufficient Data 

2.2 Pollutants of Concern 

Phosphorus is the limiting nutrient in the Everglades (McCormick et al. 1999, McCormick et al. 

2002, Noe et al. 2001). Accordingly, the TMDLs proposed in this document target phosphorus. 

Nitrogen is another plant nutrient that can contribute to eutrophication. However, because the 

Everglades marsh is phosphorus-limited, nitrogen has not been a concern. There is no numeric 

water quality criterion for total nitrogen in the Everglades. EPA is unaware of any data indicating 

that nitrogen causes imbalances in flora or fauna in Class III canals within the EAA. 

 

1

 Payne, Weaver, and Xue, 2006; Payne, Weaver, and Xue, 2007; Payne, Weaver, Goforth, and Piccone, 2005. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

19 

There are two EPA WBIDs and two EAA WBIDs that are also listed for DO. DO may be depressed 

by excess nutrients. It may also be depressed in canals due to groundwater influence. Attaining the 

appropriate levels of phosphorus is expected to result in the achievement of the DO SSAC for the 

Everglades marsh. Controlling phosphorus is expected to result in an improvement in DO within 

EAA canals to the extent that lowered DO is due to phosphorus pollution. 

2.3 Source of Pollutants 

The following discussion is adapted from SFWMD and FDEP (2007). The major source of nutrient 

pollutants to the Everglades is stormwater. The EPA is a complex system of marsh areas, canals, 

levees, and inflow and outflow water control structures covering almost 2.5 million acres (Figure 

10). The predominant source of inflow to the EPA is nonpoint source runoff resulting from rainfall. 

 The inflows are regulated by water control structures from agricultural tributaries, such as the EAA, 

that feed the EPA from the north. The EAA Basin is the largest tributary source to the EPA. 

The EAA Basin covers approximately 700,000 acres south of Lake Okeechobee in eastern Hendry 

and western Palm Beach Counties. This area of highly productive agricultural land comprises rich 

organic peat or muck soils and is considered to be one of Florida’s most important agricultural 

regions. Approximately 77 percent of the EAA is devoted to agricultural production. The major 

crops in the EAA include sugar cane, vegetables, and sod, with secondary crops in rice and citrus. 

The EPA also receives nonpoint source runoff from predominantly urbanized areas to the east 

(Figure 10). At times it also receives surface water inflows originating from Lake Okeechobee to 

the north for water supply, flood control, saltwater intrusion control, and environmental purposes. 

As part of the Everglades Construction Project (ECP), which was mandated by the Everglades 

Forever Act, the SFWMD constructed five Stormwater Treatment Areas (STA-1W, STA-2, STA3/4, STA-5, and STA-6). As part of its federal partnership with the State of Florida, the U.S. Army 

Corps of Engineers constructed a sixth STA, STA-1E, which along with the other STAs, is operated 

and maintained by the SFWMD. 

In conjunction with contributing basin BMPs, these STAs reduce phosphorus levels via naturally 

occurring biological processes prior to discharging into the Everglades. These facilities are 

considered point source discharges and, therefore, are regulated through NPDES permits, pursuant to 

403.088 F.S. in addition to Everglades Forever Act permits which are issued pursuant to 373.4592, 

F.S. 

The SFWMD owns and operates 39 water control structures discharging into, within, or from the 

EPA that are not included in the ECP. These structures, referred to as non-ECP structures, are 

operated and maintained for multiple purposes, including flood control, water supply, and the 

management of natural systems. Only 8 of the 39 water control structures discharge stormwater and 

other nonpoint source runoff from agricultural and urban areas into the EPA. 

In conjunction with landowners, local governments, and other agencies, the SFWMD has developed 

water quality improvement strategies for each of the eight non-ECP basins that discharge into the 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

20 

EPA. The first line of phosphorus control in these basins is through the implementation of BMPs at 

the source. In addition, many local and regional water resource projects are under way to further 

reduce TP loading into the EPA, including Critical Restoration Projects associated with the 

Comprehensive Everglades Restoration Plan and the Acceler8 Program. The Acceler8 program is a 

Florida initiative to accelerate specific Everglades restoration projects, including new or expanded 

STAs. 

The timing and distribution of surface inflows from the tributaries to the EPA are based on a 

complex set of operational decisions that account for natural and environmental system 

requirements, aquifer recharge, flood control, and water supply for agriculture, urban areas and 

natural areas. Each year, the EPA receives variable amounts of surface water inflows based on 

rainfall and resulting hydrologic variability in the upstream basins. These inflows also contribute a 

certain amount of TP loading to the EPA system. In some cases, surface water inflows represent a 

mixture of water from several sources as the water passes from one area to another before finally 

arriving in the EPA. For example, water discharged from Lake Okeechobee can pass through the 

EAA and then through an STA before arriving in the EPA. 

Some of the TP loading to the EPA is from atmospheric deposition. Annual average atmospheric 

deposition of TP ranges from 107 to 143 metric tons (mt) as the total contribution to the WCAs. 

Deposition rates are highly variable and very expensive to monitor and, as such, atmospheric inputs 

of TP are not routinely monitored. The range (20 to 35 milligrams per square meter per year 

[mg/m2

/yr]) is based on data obtained from long-term monitoring that was evaluated by the 

SFWMD, as reported in Redfield (2002). 

The most common water quality problems in the Everglades are elevated levels of nutrients and low 

DO. TP levels are higher than statewide medians, and most of the DO observations fall below the 

5.0 mg/l Class III water quality criterion. Many of the impaired waterbodies are canals. In 

constructed waterbodies it is difficult to consistently meet DO standards developed for natural water 

systems such as lakes and streams. In the EAA, the impaired waterbodies are canals where low DO 

concentrations occur naturally. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

21 

Figure 10. The Everglades Protection Area and tributary basins (from SFWMD and 

FDEP, 2007). 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

22 

 

3 WATER QUALITY STANDARDS

Water quality criteria established by the State of Florida are described in the Florida Administrative 

Code (F.A.C.), Section 62-302.530. The individual criteria should be considered in conjunction with 

other provisions in water quality standards, including Section 62-302.500 F.A.C. [Surface Waters: 

Minimum Criteria, General Criteria] that apply to all waters unless alternative or more stringent 

criteria are specified in F.A.C. Section 62-302.530. In addition, the designated use and water quality 

of downstream waters must be maintained. 

All waters of the EPA (wetland or canal) are designated as Class III: recreation, propagation and 

maintenance of a healthy, well-balanced population of fish and wildlife. In addition, the Refuge and 

Everglades National Park are both designated as Outstanding Florida Waters (OFWs), under Section 

62-302.700, F.A.C. This non-degradation status requires that the quality of water that existed the 

year prior to the 1979 designation is maintained. Class IV waters are designated for agricultural 

water supply. 

The WBIDs within the EAA include Class III canals as well as Class IV canals. FAC 62-

302.400(12)(a): All secondary and tertiary canals wholly within agricultural areas are classified as 

Class IV and are not individually listed as exceptions to Class III. “Secondary and tertiary canals” 

shall mean any wholly artificial canal or ditch which is behind a control structure and which is part 

of a water control system that is connected to the works (set forth in Section 373.086, F.S.) of a 

water management district created under Section 373.069 F. S., and that is permitted by such a water 

management district pursuant to Section 373.414, or Section 373.416, F.S. Agricultural areas shall 

generally include actively used solely for the production of food and fiber which are zoned for 

agricultural use where county zoning is in effect. 

FDEP has made no determination as to which canals within the EAA are Class III waters and which 

canals are Class IV waters. For purposes of this TMDL document, it is assumed that Class III canals 

within the EAA are those that are constructed by the U. S. Army Corps of Engineers or SFWMD 

that are part of the C & SF Project, and are maintained and operated by the SFWMD, or are 

considered Works of the District. Agricultural canals that have been constructed by and are operated 

by private interests are assumed to be Class IV canals with a designated use of agricultural water 

supply. 

The Everglades BMP Regulatory Program for the EAA (Rule 40E-63, F.A.C.) requires that 

dischargers to the SFWMD’s Works (canals) in the EAA basins obtain a permit for those discharges. 

 Rule 40E-63 permits approve a BMP plan and a water quality monitoring plan for TP for each subbasin or farm, as applicable. Currently, there are 33 EAA basin BMP permits, including 

approximately 205 sub-basins and 286 privately owned water control structures discharging into the 

SFWMD canals in the EAA. Most of the sub-basins have muck soils and highly managed drainage 

systems that use pumps. The areas represented by single permits vary substantially in size, from 120 

to 92,000 acres. Each permit approves an on-site implementation plan for BMPs (BMP plan) in 

accordance with the EFA (Subparagraph 373.4592[4][f][2][c], F.S.), which states that permits issued 

under the Everglades Regulatory Program require BMPs for varying crops and soil types. The BMP 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

23 

plan includes operational programs or physical enhancements designed to reduce phosphorus levels 

in water discharged to the SFWMD canals. As of 1996 the EAA basin as a whole was to have 

achieved a 25% TP load reduction in a given water year when compared to a pre-BMP baseline 

period of 1978 to 1988. The EAA met this requirement basin-wide from WY1996 to WY2007. 

All farms within the EAA are subject to this BMP rule, and all structures discharging from these 

farms into the SFWMD’s works (Class III canals) have permits. Monitoring of phosphorus and 

discharge is required at these private pumps. All canals and conveyances to the upstream side of 

these pumps are considered Class IV canals. 

3.1 Nutrient Criteria 

3.1.1 Nutrient Criteria for Class III Waters 

The designated use of Class III waters is recreation, propagation and maintenance of a healthy, wellbalanced population of fish and wildlife. FDEP has not adopted a numeric nutrient criterion for 

Class III canals within the EAA. Therefore, the Class III narrative criterion applies to these canals: 

Nutrients (62-302.530(48)(a)): The discharge of nutrients shall continue to be limited as 

needed to prevent violations of other standards contained in this chapter. Man induced 

nutrient enrichment (total nitrogen and total phosphorus) shall be considered degradation in 

relation to the provisions of Section 62-302.300, 62-302.700, and 62-4.242, FAC. 

62-302.530(48)(b) In no case shall nutrient concentrations of a body of water be altered so as 

to cause an imbalance in natural populations of aquatic flora or fauna 

For the Everglades Protection Area, in 2005 Florida established and USEPA approved a numeric 

phosphorus criterion that has been determined through research to be protective of the natural 

populations of aquatic flora and fauna of the Everglades. The phosphorus criterion is a long-term 

geometric mean of 10 ppb, as specified in Section 62-302.540, F.A.C. This numeric criterion 

applied to the entire EPA. 

3.1.2 Nutrient Criteria for Class IV Waters 

The designated use of Class IV canals is agricultural water supply. FDEP has not adopted numeric 

nutrient criteria for Class IV canals within the EAA. Therefore, the following Class IV narrative 

criterion applies to canals within the EAA: 

Nutrients (62-302.530(48) (a)): The discharge of nutrients shall continue to be limited as 

needed to prevent violations of other standards contained in this chapter. Man induced 

nutrient enrichment (total nitrogen and total phosphorus) shall be considered degradation in 

relation to the provisions of Section 62-302.300, 62-302.700, and 62-4.242, FAC. 

3.2 Dissolved Oxygen Criteria 

3.2.1 DO Criteria for Class IV Canals 

The DO criterion that applies to Class IV canals within the EAA is as follows: 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

24 

DO (62-302.530(31)): Shall not average less than 4.0 mg/l in a 24-hour period and shall 

never be less than 3.0. Normal daily and seasonal fluctuations above these levels shall be 

maintained. 

In applying the DO criterion in this TMDL, EPA also considered the definition of natural 

background and the directive not to abate natural conditions set out in Florida’s water quality 

standards. See 62-302.200(15) FAC and 62-302.300(15) FAC. 

3.2.2 DO Criteria for Class III Canals 

The DO criterion that applies to Class III canals within the EAA and Everglades is as follows: 

DO (62-302.530(31)): Shall not be less than 5.0 mg/l. Normal daily and seasonal 

fluctuations above these levels shall be maintained. 

The narrative nutrient criterion is also controlling as it relates to dissolved oxygen [62-302.530(48) 

(a)]. 

The discharge of nutrients shall continue to be limited as needed to prevent violations of 

other standards contained in this chapter. 

3.2.3 DO Site Specific Alternative Criteria 

The 1994 EFA directed FDEP and the SFWMD to evaluate existing water quality standards 

applicable to the EPA. As documented in the Everglades Consolidated and Interim Reports (1999–

2003), DO concentrations in the macrophyte- and periphyton-dominated marshes of the Florida 

Everglades routinely fall below the state Class III water quality criterion (Section 62-302.530, 

F.A.C.) of 5.0 milligrams of oxygen per liter (mg O2/L) on a daily basis and exhibit wide daily (diel) 

fluctuations due to the natural processes of photosynthesis and respiration. For example, in a 

pristine marsh community in the Park, with bladderwort and an extensive calcareous periphyton mat, 

the DO naturally fluctuated over 24 hours from 0.8 to 11.0 mg/L, and was < 5.0 mg/L for about 50% 

of the day (Scheidt et al.,1985). 

In recognition of these naturally occurring fluctuations that do not meet the Class III DO criterion, 

the FDEP established a DO Site Specific Alternative Criterion (SSAC) for the marsh within the 

EPA; this SSAC was adopted by FDEP on January 26, 2004, and approved by the USEPA on June 

16, 2004 as a revision to the Florida Water Quality Standards. Because a single-value criterion does 

not adequately account for the wide-ranging natural diel fluctuations observed in the marsh, the DO 

SSAC provides a mechanism to account for the major factors (time of day and temperature) 

influencing natural background DO variation in the Everglades. 

FDEP identified marsh reference sites within WCA 2A based on TP and ecological conditions. Diel 

data were used to define a relationship between DO, time of day and water temperature. A 

predictive sinusoidal model was developed that defines the average DO regime at these reference 

sites. The model was cross-validated with a set of reference sites from other parts of the Everglades. 

 The curve predicted by the model was then adjusted to account for natural temporal (seasonal and 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

25 

annual) and spatial variability. Since the model defines the average condition, lower natural 

fluctuations would still be expected. Therefore, the model was adjusted so that the 10% lower 

rejection limit is used as the SSAC assessment limit. Compliance with the SSAC is based on a 

comparison between the annual average of multiple DO measurements made throughout the year, 

and the average of the corresponding DO values specified by the model (Weaver, 2004). The 

achievement of the Everglades DO SSAC is assessed annually, with the results reported in the South 

Florida Environmental Report (SFER) (Weaver et al., 2007). 

3.2.4 Natural Conditions 

Florida’s water quality standards provide a definition of natural background: 

“Natural Background” shall mean the condition of waters in the absence of man-induced 

alterations based on the best scientific information available to the Department. The 

establishment of natural background for an altered waterbody may be based upon a similar 

unaltered waterbody or on historical pre-alteration data. 

See 62-302.200(15), FAC. 

Florida’s water quality standards also provide that: 

Pollution which causes or contributes to new violations of water quality standards or to 

continuation of existing violations is harmful to the waters of this State and shall not be 

allowed. Waters having water quality below the criteria established for them shall be 

protected and enhanced. However, the Department shall not strive to abate natural 

conditions. 

See 62-302.300(15) FAC. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

26 

4 TARGET IDENTIFICATION 

TMDLs identify the maximum amount of a pollutant that can be added to a waterbody without 

exceeding water quality standards. Additionally, allocations in a TMDL must not result in, or 

contribute to, any violation of other water quality standards for the waterbody or water quality 

standards downstream. 

4.1 Basis and Rationale For Phosphorus Targets 

Numeric targets for this TMDL are required to provide for a level of nutrients that will ensure 

protection for aquatic life for Class III waters. Additionally, the allocations of TMDLs for waters 

within the EAA must not impact, but protect, downstream waters of the Everglades. 

4.2 Phosphorus Target Development 

4.2.1 Everglades Protection Area 

Florida has adopted and USEPA has approved a long-term geometric mean TP criterion for the EPA 

of 10 ppb. This 10 ppb long-term geometric mean water quality criterion applies throughout the 

EPA. Walker (2005) determined that the ratio of the long-term flow-weighted mean to the long-term 

geometric mean across all STAs for 24 water years is 1.18, with a standard error 0.04. The criterion 

has been calculated to translate into an equivalent maximum annual flow-weighted concentration of 

approximately 16 ppb at discharges into the Everglades (Payne et al. 2005b, Walker 2005). Payne et 

al. (2005b) concluded that a TP effluent limit of 15.5 ppb expressed as a maximum annual flowweighted mean is recommended for incorporation into permits for all discharges into the EPA to 

assure that the discharges do not cause or contribute to exceedances of the phosphorus criterion in 

the downstream marsh receiving waters. This target can be re-evaluated in the future as more data 

become available. Although the annual maximum limit has not been formally adopted by FDEP as a 

Water Quality Based Effluent Limit (WQBEL), at the present time it represents the direct translation 

of the long-term numeric criterion to the discharge such that all water delivered to the EPA would 

meet the numeric criterion with a level of confidence. 

The 16 ppb annual maximum concentration limit is used as the basis for the TP TMDL for 

discharges to WBIDs within the EPA. This approach should assure that all waters delivered to the 

EPA at WBIDs 3252B and 3265B will meet the TP criterion. The TMDL is based on an annual 

maximum concentration-based discharge limit of 16 ppb that applies to all discharges into the EPA. 

The TMDL is applied in future years by multiplying 16 ppb TP times the annual discharge and 

conversion factors to determine the acceptable TP load limit for that year. For example, annual 

discharge into the Refuge between WY 2002 and WY2006 ranged from about 225,000 acre-feet to 

606,000 acre-feet (see Appendix D). Multiplying the 16 ppb limit by each annual discharge results 

in an annual maximum TP load limit for these years ranging from 4.4 to 12.0 metric tons per year 

(mt/yr). Likewise, annual discharge into 3265B at S-7 between WY 2002 and WY2006 ranged from 

about 98,000 to 457,000 acre-feet (Appendix D). Multiplying the 16 ppb limit by each annual 

discharge results in an annual maximum TP load limit for these years ranging from 1.9 to 9.0 mt/yr. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

27 

4.2.2 Everglades Agricultural Area 

Targets for TP in the EAA were derived from two independent approaches as described below. 

4.2.2.1 Approach #1: Estimate STA inflow loads resulting in WQS in downstream waters 

In order to meet the 10 ppb criterion and protect downstream waters of the EPA, STAs must 

discharge an annual maximum of 16 ppb. STA performance is a function of phosphorus loading rate 

(PLR), expressed as grams TP per acre of STA area per year (Kadlec 2006, Pietro et al., 2007, 

Goforth et al., 2007a-2007f). PLR was used as the basis for deriving the Technology Based Effluent 

Limits (TBELs) that are in the NPDES permits issued in September 2007 for STA 2 , STA 5 and 

STA 6 (Goforth et al., 2007a, 2007b, 2007c). As PLR increases, the projected STA discharge TP 

concentration also increases. Relationships also have been explored for TP concentration at STA 

inflow versus TP outflow concentration (Pietro et al., 2007). The best predictor of STA outflow TP 

concentration appears to be PLR. PLR and existing STA acreage can be used to calculate the 

corresponding TP inflow load to the STA that will allow attainment of the desired effluent limits 

(Table 7). The inflow TP load is the product of inflow concentration and flow. 

Pietro et al. (2007) summarize annual STA performance across all STAs for the history of the 

program. From 1995 to 2006 the three years with the lowest STA outflow concentrations (1997, 19 

ppb; 1998, 20 ppb and 1999, 19 ppb) had corresponding PLRs of 0.93, 0.82 and 0.75, and inflow TP 

concentrations of 98 ppb, 98 ppb, and 90 ppb, respectively (Table 6). Outflow TP for the other nine 

years ranged from 20 ppb to 44 ppb; PLR was always greater than 1.0, ranging from 1.26 to 3.51; 

and inflow TP concentrations were all greater than 100 ppb, ranging from 109 ppb to 147 ppb. The 

years with the performance closest to the 16 ppb discharge goal all had PLRs less than 1.0 g/m2

/yr 

and inflow TP less than 100 ppb. This 100 ppb concentration is used as the initial STA inflow target 

concentration until such time that it is demonstrated that the STAs can attain the maximum annual 

flow-weighted concentration of 16 ppb discharge goal with a higher inflow concentration. This 

concentration of 100 ppb is applied as the TMDL basis for the Class III waters within the EAA that 

discharge into the STAs. The basis is the requirement that the STAs discharges meet water quality 

standards for downstream waters. 

In addition, since Class IV agricultural waters must be of adequate quality to protect downstream 

waters, the 100 ppb TP requirement is also applied to the private pumps within the EAA WBIDs at 

the point that they discharge into the Class III canals. This 100 ppb requirement is not applied 

throughout the Class IV canals, but only at the point where they discharge into Class III canals. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

28 

 

Table 6. Years with the lowest annual STA outflow TP concentration across STAs from 1995 to 

2006 (Pietro et al., 2007).

WY 

PLR 

g/m2/y

r 

TP inflow 

flow-weighted mean 

(ppb) 

TP outflow 

flow-weighted mean 

(ppb) 

1997 0.93 98 19 

1998 0.82 98 20 

1999 0.75 90 19 

A TMDL must be adequate to assure that the designated use of as waterbody will be restored. FDEP 

has determined that the Class III canals within the EAA WBIDs are impaired for nutrients, and the 

designated use of these waters is not being met. FDEP presently uses a TP screening concentration 

of 220 ppb to indicate potential impairment for waterbodies. Because the 100 ppb goal for Class III 

waters within the EAA is much less than the 220 ppb screening level, the 100 ppb goal should result 

in attainment of the designated use for these Class III canals. If in the future FDEP changes water 

quality standards within the EAA for canals, such as by changing the designated use or adopting a 

numeric TP criterion, then this draft TMDL goal can be revisited. 

Review of the adopted TBELs for STA 2, STA 5 and STA 6 (Goforth et al. 2007a, 2007b and 

2007c) and the draft TBELs for STA 2, STA 1W and STA 1E (Goforth et al. 2007c, 2007d and 

2007e) also indicate that a PLR of 1.0 g/m2

/yr or lower is necessary in order for the STA outflow 

concentration to approach 16 ppb. Kadlec (2006) notes that in order to achieve an STA effluent of 

less than 20 ppb, STA PLR less than 1.0 is necessary. For these reasons, this TMDL assumes an 

STA PLR of 1.0 or less as a requirement for attaining a maximum annual flow-weighted 

concentration of 16 ppb at STA outflows. This TMDL can be revised in the future if STA 

performance demonstrates that a higher PLR can in fact sustain a maximum annual flow-weighted 

STA discharge of 16 ppb. 

For illustration purposes, existing STA treatment acreages are used to calculate the corresponding 

STA inflow TP load that would result in a PLR of 1.0 g/m2

/yr as follows: PLR x STA acres x unit 

conversion factors (Table 7). It should be noted that the 18,000 acre expansion of STAs that is 

underway will result in higher acceptable STA TP inflow loads while simultaneously maintaining 

the 1.0 PLR objective. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

29 

Table 7. Annual STA inflow TP loads based on PLR of 1.0 g/m2/year.

STA 

Downstream

Impaired 

WBID 

Treatment Area 

WY2006 

(acres) 

Inflow TP Load 

(metric tons) 

STA 1W 3252B 4181 17.0 

STA 1E 3252B 4024 16.3 

STA 2 3265B/F 6430 26.2 

STA 3/4 3265B/F 14,253 58.0 

4.2.2.2 Approach #2: Simple modeling approach 

A simple modeling approach was used where disturbed land use was changed in the four WBIDs 

outside of the Everglades Protection Area (3260, 3263, 3252A and 3252C) to reflect natural 

conditions (forest and wetlands). A spreadsheet based on USEPA’s Pollutant Load (PLOAD) model 

(USEPA, 2001) was used to develop TP and TN targets. The spreadsheet was used to calculate 

nonpoint source loadings for nutrients as the product of the water quality concentration and runoff 

volume associated with certain land use practices. For these four WBIDs TP target concentrations 

are based on undisturbed conditions. Land uses classified as urban, agriculture, pasture, 

commercial, industrial, extractive or barren were considered disturbed categories and were changed 

to wetlands. Runoff volumes were calculated using estimates of annual average rainfall and Event 

Mean Concentrations (EMCs) for the various land uses. Annual average rainfall for the EAA is 

about 50.2 inches. Event Mean Concentrations (EMCs) assumed for each land use type in Florida 

were selected from those compiled by Harper and Baker (2003). Model results from the four 

WBIDs indicate that the TP concentration for natural conditions was projected to be 82 ppb to 89 

ppb, with an average concentration of 87 ppb (Appendix E). 

This procedure is designed to estimate loading to the Class III canal. It does not contain any water 

quality dynamics or a link to aquatic life use support but assumes that aquatic life is supported under 

natural conditions. The utility of this tool is best used to predict background, or undisturbed, loading 

to the canal which is then used to estimate natural resulting concentrations. The 87 ppb average TP 

concentration is similar to the 100 ppb STA inflow requirement. Therefore, EPA is assuming that 

the 100 ppb STA inflow target will also protect the designated uses of the EAA canals. 

4.3 DO Target 

FDEP established a DO Site Specific Alternative Criterion (SSAC) for the marsh within the EPA to 

address the naturally occurring fluctuations in DO in the marsh that do not meet the Class III DO 

criterion of 5.0 mg/L. Therefore, the DO target for WBIDs within the EPA is the DO SSAC. EPA 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

30 

anticipates that attainment of the 10 ppb long-term TP criterion in those portions of the Everglades 

marsh not attaining the DO SSAC (WBIDs 3252B and 3265B) will result in those WBIDs attaining 

the SSAC. 

The DO target for the remainder of the Class III waters in the EPA and EAA is Florida’s applicable 

water quality standard for DO of 5 mg/L. EPA notes, however, that it is likely that many of these 

waters will not attain the applicable water quality standard for DO, even if the nutrient loads 

established in this TMDL are met. All Everglades canals are artificial conveyances that are 

influenced by groundwater which contains very low DO concentrations. Even canals within the 

Everglades with extremely low TP concentrations, such as the Tamiami Canal at Everglades 

National Park, typically have natural DO concentrations that are less than the 5.0 mg/L Class III 

criterion, especially before noon. In canals that are not nutrient impaired, attainment of the TP 

criterion does not necessarily mean that the DO criterion will be met. EPA believes that the nutrient 

target for this TMDL, which is based on a consideration of natural levels of TP as well as the level 

of TP that can be delivered to STAs and still protect the downstream Everglades marshes, limits TP 

so that it does not exert a negative effect on DO, as required by Florida’s narrative criterion for 

nutrients. See 62-302.530(48)(a), FAC. Limiting TP beyond this point is not expected to have any 

additional beneficial effect on DO. A revised DO criterion (SSAC) for canals that are not impaired 

by nutrients should be considered to recognize that DO is naturally low in these artificial 

waterbodies. FDEP is in the process of investigating revised DO criteria for canals. 

The DO target for the Class IV canals in the EAA is Florida’s applicable water quality standard: 

shall not average less than 4.0 mg/L in a 24-hour period and shall never be less than 3.0 mg/L. 

Similarly to the Class III canals, EPA does not expect the Class IV canals to attain the DO minimum 

of 3.0 mg/L at all times, even if the TP goal is met. For example, WBIDs 3260 and 3263 meet the 

100 ppb TP goal, yet these waters are listed as impaired for DO. As set above regarding the Class 

III canals, EPA believes this TMDL limits TP so that it does not exert a negative effect on DO, as 

required by Florida’s narrative criterion for nutrients. A revised criterion should be considered by 

FDEP that would recognize that DO is naturally low in these artificial waterbodies. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

31 

5 WATER QUALITY RESULTS 

Current phosphorus conditions within the EAA are shown in Table 8. Summary data for each 

WBID are presented in two ways. The annual mean TP concentration for each farm discharge was 

summarized by WBID (see Appendix D and references). The overall arithmetic mean for the WBID 

was then calculated. In addition, the TP concentrations were also weighted by the acreage of each 

farm (area-weighted) in order to more accurately reflect overall loading conditions for the WBID. 

The arithmetic mean of annual discharge data For WY 2007 discharge TP concentrations by farm 

field post-BMP ranged from 23.5 ppb to 629 ppb (Van Horn and Pescatore 2007). During WY 2002 

to WY2006 TP concentrations in the EAA WBIDs that are the subject of this TMDL document, 

weighted by farm acreage, averaged 63 ppb for the S-8 basin (WBID 3260), 94 ppb for the S-7 basin 

(WBID 3263) and 168 ppb for Knight’s Farm Field 1 (WBID 3252A) (Appendix D). 

 

Figure 11. WY2006 flow-weighted mean TP concentrations in the EAA (Van Horn and 

Pescatore 2007). 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

32 

For WY2002 to WY2006 the average TP concentration discharged into the Refuge (from STA-1W, 

STA-1E, G-300 and G-301) at WBID 3252B was 87 ppb, with an average annual load of 39 metric 

tons. For WY2002 to WY2006 the average TP concentration discharged into WBID 3265B at S-7 

was 36 ppb, with an average annual load of 8 metric tons. It should be noted that once STA 3/4 

came on line in 2004, TP concentrations at S-7 decreased (see Table 4). During WY2002-WY2004, 

TP load data for EAA farms were not reported. 

Table 8. WY2002 to WY 2006 TP concentration and load for EAA and EPA WBIDs.

WBID 

WY2002-WY2006 

 TP concentration 

(ppb) 

Area-weighted 

WY2002-WY2006 

 TP concentration 

 (ppb) 

WY2002-WY2006 

TP load 

 (metric tons/year)

3263 

S-7 

93.8 ppb 

Post-BMP 

89.9 ppb 

Post-BMP 45.0* 

3260 

S-8 

62.7 ppb 

Post-BMP 

91.9 ppb 

Post-BMP 35.2* 

3252A 

Knights Farm Field 1 

168.0 ppb 

Post-BMP 

164.8 ppb 

Post-BMP 52.9* 

3252C ACME North 

Sector - 115.2 ppb 3.5 

3265B 

WCA 2B - 36 ppb into 8.2 into 

3252B 

Refuge North Sector - 87 ppb into 39.4 into 

EAA farm data are from Sievers et al. 2003, McGinnes et al. 2004, McGinnes et al. 2005, Pescatore 

and Vega 2006, and Van Horn et al. 2007. ACME data are from Goforth et al. 2003, Piccone et al. 

2004, Payne et al. 2005a, 2006, 2007. 

* loads were only reported for WY2005-WY2006. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

33 

6 SOURCE ASSESSMENT 

An important part of the TMDL analysis is the identification of source categories and the amount of 

pollutant loading contributed by these sources. Sources are broadly classified as either point or 

nonpoint sources. Phosphorus originating from atmospheric deposition is allocated to background 

loads. Several of the WBIDs are also impaired for DO. The sources contributing to nutrient 

impairment can also contribute to the low DO. Low DO concentrations in canals may also be 

attributed to groundwater influence due to channelization. 

6.1 Background Loads 

A certain amount of TP loading to the EPA is from atmospheric deposition. Annual average 

atmospheric deposition of TP ranges from 107 to 143 metric tons (mt) as the total contribution to the 

WCAs. Deposition rates are highly variable and very expensive to monitor and, as such, 

atmospheric inputs of TP are not routinely monitored. The range (20 to 35 milligrams per square 

meter per year [mg/m2

/yr]) is based on data obtained from long-term monitoring that was evaluated 

by the SFWMD, as reported in Redfield (2002). 

6.2 Permitted Point Sources 

A point source is defined as a discernable, confined, and discrete conveyance from which pollutants 

are or may be discharged to surface waters. Point source discharges of industrial wastewater and 

treated sanitary wastewater must be authorized by National Pollutant Discharge Elimination System 

(NPDES) permits. NPDES permitted facilities discharging treated stormwater are typically 

considered primary sources of nutrients. Waste Load Allocations (WLAs) are assigned to all 

NPDES permits discharging to surface waters. 

6.2.1 Traditional Point Sources 

Traditional point sources are defined as continuous release municipal or industrial wastewater 

NPDES permitted facilities. There are no traditional NPDES facilities discharging to surface waters 

in the impaired WBIDs. 

6.2.2 Stormwater Treatment Areas (STAs) 

Stormwater Treatment Areas (STAs) are large parcels of wetlands planted with specific species that 

act as filters to remove nutrients. The STAs remove phosphorus from agricultural stormwater 

runoff, facilitating restoration of downstream waterbodies. The four STAs discharging into EPA 

WBIDs 3252B and 3265B are subject to NPDES permit requirements (Table 9). For STA-2, 

interim period 1 applies when three STA flow-ways are in operation, and interim period 2 applies 

when four flow-ways are in operation (Goforth et al., 2007a) 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

34 

 

Table 9. Permitted Facilities Discharging into impaired EPA WBIDs.

Name of Facility Facility ID WBID Annual maximum 

TP limit (ppb) 

 STA-1E FL0304549 3238E 68 * 

 STA-1W FL0177962 3238C 68 * 

 STA-2 FL0177946 3254A 

 Interim Period 1 30.4 -38.9 

 Interim Period 2 22.4 – 28.8 

 STA-3/4 FL0300195 3262B 68 * 

* based on the initial 1994 goal of 50 ppb, not the new criterion of 10 ppb adopted in 2005. Applies 

only when the STA is in the post-stabilization operations phase. 

6.2.3 Municipal Separate Storm Sewer System Permittees 

Like other nonpoint sources of pollution, urban stormwater discharges are associated with land use 

and human activities, and are driven by rainfall and runoff processes leading to the intermittent 

discharge of pollutants in response to storms. The 1987 amendments to the Clean Water Act 

designated certain stormwater discharges from urbanized areas as point sources requiring NPDES 

stormwater permits. The three major components of the NPDES stormwater regulations are: 

• Municipal Separate Storm Sewer Systems (or MS4) permits that are issued to entities that own 

and operate master stormwater systems, primarily local governments. Permittees are required to 

implement comprehensive stormwater management programs designed to reduce the discharge 

of pollutants from the MS4 to the maximum extent practicable. 

• Stormwater Associated with Industrial Activities, which is regulated primarily by a multisector 

general permit that covers various types of industrial manufacturing facilities and requires the 

implementation of stormwater pollution prevention plans. 

• Construction activity generic permits for projects that disturb one or more acres of land and 

which require the implementation of stormwater pollution prevention plans to provide for 

erosion and sediment control during construction and the treatment and management of 

stormwater to minimize pollution and flooding. 

In October 2000, USEPA authorized FDEP to implement the NPDES stormwater program in all 

areas of Florida except Indian Tribal lands. FDEP’s authority to administer the NPDES program is 

set forth in Section 403.0885, Florida Statutes. The Stormwater Rule was established as a 

technology-based program that relies on the implementation of BMPs that are designed to achieve a 

specific level of treatment (i.e., performance standards) as set forth in Chapter 62-40, F.A.C. 

The Stormwater Rule requires the state’s water management districts (WMDs) to establish 

stormwater pollutant load reduction goals (PLRGs) and adopt them as part of a Surface Water 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

35 

Management Plan, other watershed plan, or rule. Stormwater PLRGs are a major component of the 

load allocation part of a TMDL. To date, stormwater PLRGs have been established for Tampa Bay, 

Lake Thonotosassa, the Winter Haven Chain of Lakes, the Everglades, Lake Okeechobee, and Lake 

Apopka. 

The NPDES stormwater program was implemented in phases, with Phase I MS4 areas including 

municipalities having a population above 100,000. Because the master drainage systems of most 

local governments in Florida are interconnected, EPA implemented Phase 1 of the MS4 permitting 

program on a countywide basis, which brings in all cities, Chapter 298 urban water control districts, 

and the Florida DOT throughout the fifteen counties meeting the population criteria. Phase II of the 

NPDES Program was expanded in 2003 and requires stormwater permits to construction sites 

between one and five acres, and to local governments with as few as 10,000 people. 

Although MS4 discharges are technically referred to as “point sources” for the purpose of 

regulation, they are still diffuse sources of pollution that cannot be easily collected and treated by a 

central treatment facility. Most MS4 permits issued in Florida include a re-opener clause allowing 

permit revisions for implementing TMDLs once they are formally adopted by rule. 

MS4 entities covering the drainage basins of the impaired WBIDs are shown in Table 10. The only 

MS4 permit is in WBID 3252C and is for the Village of Wellington. There are no urban areas in the 

WBIDs 3260, 3263 or 3252A of sufficient population to be covered by an MS4 permit. All future 

areas with populations meeting the MS4 requirements will be required to achieve the allocations 

presented in the TMDL. 

Table 10. MS4 Permitees in the Drainage Basins of Impaired WBIDs.

County Permit/Co-Permit Name Permit ID Number MS4 Type 

Palm Beach Village of Wellington FLS000018 Phase II 

6.3 Nonpoint Sources 

Unlike traditional point source effluent loads, nonpoint source loads are diffuse sources that cannot 

be identified as entering a waterbody through a discrete conveyance at a single location. These 

sources generally, but not always, involve accumulation of nutrients on land surfaces that wash off 

as a result of storm events. Nonpoint sources of phosphorus loadings in the Everglades watershed 

include agriculture, wildlife, and stormwater runoff. All non-point runoff that is delivered to the 

EPA passes through a water control structure, and is easily monitored for discharge volume and 

nutrient concentrations. A summary of anthropogenic nonpoint sources in the Everglades watershed 

is presented below. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

36 

6.3.1 Agriculture 

Agricultural activities, which are the principle land uses in the impaired WBIDs, discharge large 

quantities of nutrients to the waterbodies through stormwater runoff. 

Sugarcane has been grown commercially in the EAA since the 1920s and is one of the most 

economically important crops in the state. Sugarcane planting and harvesting operations are 

conducted during the fall and winter. During the summer wet months area farms store water by 

flooding vacant sugarcane fields or by growing paddy rice. Sugarcane is planted in rotation with 

rice, sod, spring and fall corn, and other assorted vegetables. To maximize the efficient use of plant 

nutrients in the soil, a rotation from higher to lower fertility requiring crops is normally practiced. 

Like any other plant, sugarcane requires nutrients for optimum growth. In the EAA, nutrients are 

provided from rainfall, irrigation water, organic soils, and fertilizer. Research studies based on yield 

responses have been used to establish guidelines currently used for fertilizer rates. Studies have 

shown that sugarcane biomass removes more phosphorus from the soil than the amount applied as 

fertilizer. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

37 

7 TMDL ALLOCATION 

TMDLs identify the maximum amount of nutrients that can be added to a waterbody without 

exceeding water quality standards so as to protect the listed waterbodies and the downstream 

Everglades Protection Area. 

The TMDL process quantifies the amount of a pollutant that can be assimilated in a waterbody, 

identifies the sources of the pollutant, and recommends regulatory or other actions to be taken to 

attain the applicable water quality standards based on the relationship between pollution sources and 

in-stream water quality conditions. The objective of a TMDL is to allocate loads among all of the 

known pollutant sources throughout a watershed so that appropriate control measures can be 

implemented and water quality standards achieved. 

7.1 Allocation 

A TMDL can be expressed as the sum of all point source loads (Wasteload Allocations or WLA), 

nonpoint source loads (Load Allocations or LA), and an appropriate margin of safety (MOS), which 

accounts for uncertainty concerning the relationship between effluent limitations and water quality: 

TMDL = Σ WLAs + Σ LAs + MOS 

Federal regulations provide that TMDLs can be expressed in terms of mass per time (e.g. pounds per 

day), toxicity, or other appropriate measure (40 C.F.R.§ 130.2(i)). TMDLs for the EPA WBIDs are 

expressed as annual maximum flow-weighted TP concentration. Corresponding annual and daily 

loads are also presented for information purposes. However, attainment of the TMDL is based on 

the TP concentrations of 16 ppb (annual maximum) for waters discharged into the EPA and 100 ppb 

(annual average) within the EAA for waters discharged into Class III canals or the STAs. Annual 

flows in the Everglades fluctuate due to variation in annual rainfall. Flow will also vary over time as 

a series of new restoration activities are constructed and become operational (STA expansion, 

conveyance canals, water control structures, etc.) Strategies implemented in the watershed to 

achieve the TP TMDLs should also improve DO conditions to the extent that excess phosphorus is 

lowering DO. 

The TMDL components are provided in Table 11 and are expressed as annual concentrations. The 

TMDL for EPA WBIDs is applied by multiplying 16 ppb times the annual flow and appropriate 

conversion factors. The target TP concentrations represent annual values and the TMDLs should be 

implemented to achieve the annual concentrations. An implicit Margin of Safety (MOS) is assumed 

in all of these TMDLs as described in Section 7.4. The percent reduction required to achieve water 

quality standards is calculated using the following equation: 

 % Reduction = (existing load – TMDL) / (existing load) * 100 

7.2 Load Allocation (LA) 

A LA is assigned to nonpoint sources in the watershed. For the EPA WBIDs, it is assumed that all 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

38 

inflow is treated by STAs. Therefore, there are no nonpoint sources in the WBID and the entire 

TMDL is allocated to the Wasteload Allocation. Any water that does not pass through an STA 

before being discharged into these EPA WBIDs is still subject to the 16 ppb flow-weighted annual 

maximum requirement of this TMDL. 

For the EAA WBIDs, there are no traditional NPDES facilities, MS4s or permitted STAs within 

these WBIDs. The entire TMDL is assigned to the Load Allocation. The TMDL was determined by 

reducing the WY2002 to WY 2006 TP loads and concentrations to meet the 100 ppb inflow target. 

7.3 Wasteload Allocation (WLA) 

For the EPA WBIDs it is assumed that all inflow is treated by STAs. Therefore the entire load into 

these WBIDs is assigned to the wasteload allocation. In future years the TMDL is applied by 

multiplying 16 ppb times the annual flow and appropriate conversion factors. The WLA is to be 

reflected in the NPDES permits for the appropriate STAs. All future point sources discharging to 

surface waters impacting the impaired WBIDs will be required to meet the 16 ppb requirement 

established in these TMDLs. 

7.4 Margin of Safety 

An implicit margin of safety for waterbody protection was provided in the TMDL analysis. The 

maximum annual flow-weighted TP concentration of 16 ppb is equivalent to the 10 ppb long-term 

geometric mean criterion for the Everglades marsh. This was based in part on STA performance 

data. This approach assumes that the same discharge limit can be applied to all STAs and inflows. 

Application of the TP criterion at the discharge point into the EPA assumes that there is no 

assimilative capacity in the receiving canals and marsh (i.e., any TP above the criterion would result 

in a phosphorus change that would be determined to be an imbalance). For the EAA WBIDs, the 

100 ppb target was derived as what is necessary at STA inflows in order to protect downstream 

waters of the EFA. This 100 ppb target (applied to Class III canals within the EAA and Class IV 

discharges into Class III canals) is less than the 220 ppb screening level presently used by FDEP for 

TP impairment. This results in a margin of safety for protection of the designated use of these Class 

III waters within the EAA. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

39 

 Table 11. TMDL allocation for Total Phosphorus

Notes: 

1. TMDL expressed as an average annual load is calculated by multiplying 16 ppb times the annual 

flow and conversion factors. To express the TMDL as a daily load, the annual load is divided by 

365 days per year. 

2. Based on STA inflow need of 100 ppb to meet STA effluent of 16 ppb annual maximum. 

3. Allocation given to Class IV canals necessary to protect the downstream Class III waters and 

should be implemented and monitored at the point of entry into Class III waters. 

4. Based on WY2002-WY2006 data 

5. Assumes all flow into this WBID is treated by STAs with NPDES permits. 

WBID Water 

Class 

TMDL1,2,3

(ppb) WLA (ppb) LA (ppb)2,3 MOS Percent Reduction4

Everglades Agricultural Area or ACME Improvement District 

Class III 100 0 100 Implicit 0% 

3263 (S-7) 

Class IV 100 0 100 (at inflow to 

Class III canal) Implicit 0% 

Class III 100 0 100 Implicit 0% 

3260 (S-8) 

Class IV 100 0 100 (at inflow to 

Class III canal) Implicit 0% 

Class III 100 0 100 Implicit 41% 

3252A (Knight’s 

Farm Field 1) Class IV 100 0 100 (at inflow to 

Class III canal) Implicit 41% 

3252C (ACME 

North Sector) Class III 100 0 100 Implicit 13% 

Everglades Protection Area 

3265B (3265F, 

3265H; WCA2A 

Southwest Sector) 

Class III 16 (see note 5) 16 Implicit 56% 

3252B (Refuge 

North Sector) Class III 16 (see note 5) 16 Implicit 82% 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

40 

7.5 Seasonal Variability 

Seasonal variability was addressed in the selection of the nutrient target concentrations by 

considering data collected during all seasons. The data used for deriving the TP targets for the EPA 

and EAA include many years and seasons, various rainfall conditions, and several years of STA 

data. The data used to determine an acceptable TP loading rate and inflow for the STAs likewise 

capture over 10 years that include wet and dry conditions, various rainfall conditions, and drought 

and hurricanes. 

8 TMDL IMPLEMENTATION 

The Clean Water Act [Section 303(d)(2)] directs that a TMDL established by the Environmental 

Protection Agency be implemented by a State pursuant to subsection 303(e). A State can establish 

its own procedures for implementation. Federal regulations provide direction on implementation of 

TMDLs in the permitting process. At a minimum, NPDES permits must include a permit limit 

consistent with the assumptions of an approved wasteload allocation. Presently, STA 2 has an 

issued NPDES with such an initial TBEL permit limit. STA 1W, STA 1E, and STA3/4 do not have 

such permits. 

Implementation of these TMDLs is the responsibility of Florida. Attainment of the TMDL may 

necessitate a variety of measures depending upon the basin and the existing quality of water. Florida 

has laid out such measures in their long-term plan for achieving water quality goals for tributary 

basins to the EPA. STA PLR is a function of STA size, inflow volume and inflow TP concentration. 

 STA inflow concentration and flow can be affected by many factors including land use practices, 

agricultural BMP effectiveness and delivery of water from Lake Okeechobee. Decisions about how 

to attain these TMDL targets are left to the expertise of FDEP, SFWMD and private interests. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

41 

9 REFERENCES 

Cooper, Richard M. 1989. An atlas of the Everglades Agricultural Area surface water 

management basins. South Florida Water Management District Technical Memorandum. 

 West Palm Beach, Florida. 

Florida Administrative Code (F.A.C.) 62-302.530. Criteria for Surface Water Quality 

Classifications. 

Goforth, Gary, Tracey Piccone, Stuart Van Horn, Doug Pescatore and Cheol Mo. 2003. Chapter 

8A: achieving long-term water quality goals. 2003 Everglades Consolidated Report. 

South Florida Water Management District. West Palm Beach, Florida. 

Goforth, Gary, Nenad Iricanin, Steve Hill, Shi Kui Xue, Tracey Piccone, Frank Nearhoof and 

Ken Weaver. 2007a. Technical support document for the STA-2 TBEL. May 17, 2007. 

 

Goforth, Gary, Nenad Iricanin, Steve Hill, Shi Kui Xue, Tracey Piccone, Frank Nearhoof and 

Ken Weaver. 2007b. Technical support document for the STA-5 TBEL. June 3, 2007. 

Goforth, Gary, Nenad Iricanin, Steve Hill, Shi Kui Xue, Tracey Piccone, Frank Nearhoof and 

Ken Weaver. 2007c. Technical support document for the STA-6 TBEL. June 3, 2007. 

Goforth, Gary, Nenad Iricanin, Steve Hill, Shi Kui Xue, Tracey Piccone, Frank Nearhoof and 

Ken Weaver. 2007d. Technical support document for the STA-1W TBEL. July 5, 2007. 

Goforth, Gary, Nenad Iricanin, Steve Hill, Shi Kui Xue, Tracey Piccone, Frank Nearhoof and 

Ken Weaver. 2007e. Technical support document for the STA-1E TBEL. July 5, 2007. 

Goforth, Gary, Nenad Iricanin, Steve Hill, Shi Kui Xue, Tracey Piccone, Frank Nearhoof and 

Ken Weaver. 2007f. Technical support document for the STA-3/4 TBEL. March 21, 

2007. 

Harper, H. H. and D. M. Baker. 2003. Evaluation of alternative stormwater regulations for 

southwest Florida. Environmental research and design, Inc. 

Kadlec, Robert H. 2006. Free surface wetlands for phosphorus removal: the position of the 

Everglades Nutrient Removal Project. Ecological Engineering 27 (2006):361-379. 

McCormick, Paul C., Susan Newman, ShiLi Miao, Ramesh Reddy, Dale Gawlik, Carl Fitz, Tom 

Fontaine and Darlene Marley. 1999. Ecological Needs of the Everglades. Chapter 3 in 

Everglades Consolidated Report. January 1, 1999. South Florida Water Management 

District. 

McCormick, P. V., S. Newman, S. Miao, D. E. Gawlick, D. Marley, K. R. Reddy, T. D. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

42 

Fontaine. 2002. Effects of anthropogenic phosphorus inputs on the Everglades. pages 

83-126 in J. W. Porter and K. G. Porter, eds. The Everglades, Florida Bay, and coral 

reefs of the Florida Keys: An ecosystem sourcebook. CRC Press LLC, Boca Raton, FL. 

McGinnes, Paul, Doug Pescatore and Jose Vega. 2005. Appendix 3-1: Water year 2004 permitlevel data. 2005 South Florida Environmental Report. South Florida Water Management 

District. West Palm Beach, Florida. 

McGinnes, Paul, Doug Pescatore and Jose Vega. 2004. Appendix 3-1: Water year 2003 permitlevel data. 2004 South Florida Environmental Report. South Florida Water Management 

District. West Palm Beach, Florida. 

Noe, G. B., D. L. Childers, and R. D. Jones. 2001. Phosphorus biogeochemistry and the impact 

of phosphorus enrichment: Why is the Everglades so unique? Ecosystems 4:603-624. 

Payne, Grover, Kenneth Weaver, Gary Goforth and Tracey Piccone. 2005a. Chapter 2C: status 

of phosphorus and nitrogen in the Everglades Protection Area. 2005 South Florida 

Environmental Report. South Florida Water Management District. West Palm Beach, 

Florida. 

Payne, Garry, Kenneth Weaver and Frank Nearhoof. 2005b. Draft. Derivation of the water 

quality based effluent limit (WQBEL) for phosphorus discharges to the Everglades 

Protection Area. Florida Department of Environmental Protection. Tallahassee, Florida. 

Payne, Grover, Kenneth Weaver and Shi Kui Xue. 2006. Chapter 2C: status of phosphorus and 

nitrogen in the Everglades Protection Area. 2006 South Florida Environmental Report. 

South Florida Water Management District. West Palm Beach, Florida 

Payne, Grover, Kenneth Weaver and Shi Kui Xue. 2007. Chapter 3C: status of phosphorus and 

nitrogen in the Everglades Protection Area. 2007 South Florida Environmental Report. 

South Florida Water Management District. West Palm Beach, Florida 

Pescatore, Doug and Jose Vega. 2006. Appendix 3-1a: Water year 2005 permit-level data. 

2006 South Florida Environmental Report. South Florida Water Management District. 

West Palm Beach, Florida. 

Piccone, Tracey, Gary Goforth, Stuart Van Horn, Doug Pescatore and Guy Germain. 2004. 

Chapter 8A: achieving long-term water quality goals. 2004 Everglades Consolidated 

Report. South Florida Water Management District. West Palm Beach, Florida. 

Pietro, Kathleen, Ron Bearzotti, Michael Chimney, Guy Germain, Nenad Iricanin and Tracey 

Piccone. 2007. Chapter 5: STA performance, compliance and optimization. 2007 South 

Florida Environmental Report. South Florida Water Management District. West Palm 

Beach, Florida. 

Redfield, G. 2002. Atmospheric deposition of phosphorus: concepts, constraints and published 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

43 

deposition rates for ecosystem management. SFWMD (EMA) Report 403. South Florida 

Water Management District. West Palm Beach, Florida. 

Rutchey, K., and L. Vilchek. 1994. Development of an Everglades map using SPOT image and 

global positioning system. Photogrammetric Engineering and Remote Sensing. 60:767-775. 

Scheidt, Daniel J., David R. Walker, Ramona G. Rice and Mark D. Flora. 1985. Diel dissolved 

oxygen levels under experimental nutrient loading conditions in Shark Slough, Everglades 

National Park, Florida. Florida Scientist 48: supplement 1:36. 

Scheidt, D. J. and P. I. Kalla. 2007. Everglades ecosystem assessment: water management, 

water quality, eutrophication, mercury contamination, soils and habitat. Monitoring for 

adaptive management: a R-EMAP status report. EPA 904-R-07-001. United States 

Environmental Protection Agency. Atlanta, Georgia. 

Sievers, Pamela, Doug Pescatore, Jose Vega and Nancy Wilson. 2003. Appendix 3-1: Water 

year 2002 permit-level data. 2003 South Florida Environmental Report. South Florida 

Water Management District. West Palm Beach, Florida. 

South Florida Water Management District and Florida Department of Environmental Protection. 

 2007. Reasonable assurances documentation for the Everglades Protection Area. 

Final. August 2007. 

University of Florida. 2001. Florida water Resources. University of Florida Extension Institute 

of Food and Agricultural Sciences WQ101. Gainesville, Florida. April 2001. 

USEPA, 1991. Guidance for Water-Quality Based Decisions: the TMDL Process. United 

States Environmental Protection Agency, Office of Water, Washington, DC EPA-440/4-

91-001. April 1991. Washington, D. C. 

USEPA, 2000. Nutrient Criteria Technical Guidance Manual, Rivers and Streams. United 

States Environmental Protection Agency, Office of Water, Washington, DC EPA-822-B00-002. Washington, D. C. 

USEPA, 2001. BASINS PLOAD Version 3.0 users manual. United States Environmental 

Protection Agency, Office of Water, Washington, DC. 

Walker, William W. Jr. 2005. Estimation of water quality based effluent limits for measuring 

compliance with the Everglades phosphorus criterion. Draft for discussion purposes. 

2005. 14 pages 

Weaver, K. 2004. Everglades Marsh Dissolved Oxygen Site Specific Alternative Criterion 

Technical Support Document. Tallahassee, Florida: Florida Department of Environmental 

Protection. 

Weaver, K., and G. Payne. 2004. Chapter 2A: Status of Water Quality in the Everglades 

Protection Area. G. Redfield (Ed.). In: 2004 Everglades Consolidated Report. West Palm 

Beach, Florida: South Florida Water Management District. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

44 

Weaver, K., G. Payne, and S. Xue. 2007. Chapter 3A: Status of Water Quality in the 

Everglades Protection Area. G. Redfield (Ed.). In: 2007 South Florida Environmental 

Report – Volume I. West Palm Beach, Florida: South Florida Water Management District. 

Van Horn, Stuart and Doug Pescatore. 2007. Appendix 4-2: Water year 2006 permit-level data. 

 2007 South Florida Environmental Report. South Florida Water Management District. 

West Palm Beach, Florida. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

45 

APPENDIX A: Summary of Everglades WBIDs. Draft TMDLs due September 30, 2007 

are shaded in yellow. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

46 

WBIDs WBID NAME 1998 303(d) WBID Waterbody Type 

EVERGLADES 

LONG-TERM PLAN BASIN 

NAME 

Nutrient 

TMDL on 

1998(d) list 

CD YEAR 

NUTRIENT 

TMDL DUE 

Desi

U

WITHIN EVERGLADES PROTECTION AREA 

LOXAHATCHEE NATIONAL WILDLIFE REFUGE 3252B WCA1 north sector A Unchanged Everglades Marsh NA YES 2007 Class 3252D WCA1 west sector Unchanged Everglades Marsh NA NONE Class 3252 WCA1 center sector Unchanged Everglades Marsh NA YES 2012 Class 3252G WCA1 east sector A Unchanged Everglades Marsh NA NO NONE Class 3252E WCA1 south sector Unchanged Everglades Marsh NA YES 2012 Class 3252H LOXA west sector Everglades Marsh NA NO NONE WATER CONSERVATION AREA 2 3265G WCA2A center sector 

3265A, 3265E, 3265D, 3265 Everglades Marsh NA YES 2012 Class 

3265H WCA2A center sector 

3265B, 3265E, 3265D, 3265 Everglades Marsh NA YES 2007 Class 

3265F WCA2A center sector 3265B, 3265D Everglades Marsh NA YES 2007, 2012 Class 3272 WCA2B Unchanged Everglades Marsh NA YES 2012 Class WATER CONSERVATION AREA 3 3268H WCA3A south sector 

3268, 3268A, 3268B, 3278A Everglades Marsh NA YES 2012 Class 

3268I WCA3A south sector 3268, 3268B, 3268C Everglades Marsh NA YES 2012 Class 3268G WCA3A south sector 

3268, 3268B, 3268C, 3268D Everglades Marsh NA YES 2012 Class 

3268F WCA3A south sector 3278A Everglades Marsh NA YES 2012 Class 3268J WCA3A south sector 3278, 3278E Everglades Marsh NA YES 2012 Class EVERGLADES NATIONAL PARK 3289J ENP L-67 culvert US 41 Unchanged Everglades Marsh NA NO NONE Class 3289 ENP Shark Slough Unchanged Everglades Marsh NA YES 2008 Class 3289K ENP Taylor Slough Unchanged Everglades Marsh NA NO NONE Class 3303 C-111 Unchanged Everglades Marsh NA NO NONE Class 3261B Tamiami Canal Unchanged 

Big Cypress Swamp NA NO NONE Class 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

47 

WBIDs WBID NAME 1998 303(d) WBID Waterbody Type 

EVERGLADES 

LONG-TERM PLAN BASIN 

NAME 

Nutrient 

TMDL on 

1998(d) list 

CD YEAR 

NUTRIENT 

TMDL DUE 

Desi

U

WBIDS DISCHARGING INTO THE EVERGLADES PROTECTION AREA

FROM EAA (NORTH)3233 Canal, Farms L-8 NO 

TMDL done under LO tribs Class 

3238E M canal Canal, Farms S-5A NO NONE Class 3238 West Palm Beach Canal Canal, Farms S-5A NO NONE Class 3244 East Beach Canal, Farms NA NO NONE Class 3247 715 Farms Canal, Farms NA NO NONE Class 3249 East Shore Canal, Farms NA NO NONE Class 3248A Hillsboro Canal Canal, Farms S-7/S-2 YES 2012 2006 Class 3252A Knights Farm field 1 Canal, Farms S-5A YES 2007 Class 3254 Hillsboro Canal Canal, Farms S-6 YES 2012 Class 3253 South Bay Canal, Farms NA NO NONE Class 3248 North New river canal Canal, Farms S-2/S-7 NO NONE Class 3263 S-7 Canal, Farms S-7 YES 2007 Class 3263A Holeyland 

Everglades Marshnot in EPA S-7 YES 2012 Class 

3260B Holeyland 

Everglades Marshnot in EPA S-8 NO NONE Class 

3250 S-236 Canal, Farms NA YES 2012 Class 3251 S-3 Canal, Farms S-3/S-8 NO NONE Class 3260 S-8 Canal, Farms S-8 YES 2007 Class FROM WEST 3255 Canal, Farms C-139 NO NONE Class 3260A L3 Canal, Farms S-8 YES 2012 Class 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

48 

WBIDs WBID NAME 1998 303(d) WBID Waterbody Type 

EVERGLADES 

LONG-TERM PLAN BASIN 

NAME 

Nutrient 

TMDL on 

1998(d) list 

CD YEAR 

NUTRIENT 

TMDL DUE 

Desi

U

3266 L28 Interceptor 

Canal, Farms, Seminole Reservation, Miccosukee Reservation L-28 YES 2012 

FloridClass MiccoClass SemiClass 

3267 Canal, Farms Feeder Basin NO NONE Class 3269 L-28 gap 

Big Cypress Swamp NA NO NONE Class 

3261B 

Big Cypress Swamp NA NO NONE Class 

FROM EAST 3252C Canal, Farms YES 2007 3252F Canal, Farms ACME B YES 2012 Class 3264 Urban NSID NO NONE Class 3275 Urban NNRC NO NONE Class 3277C Urban NNRC YES 2011 Class 3277 Urban NNRC YES 2011 Class 3277B Urban NNRC NO NONE Class 3280 Urban NNRC NO NONE Class 3279 Urban C-11W YES 2011 Class 3301 Urban NO NONE Class 3303A Urban NO NONE Class 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

49 

WBIDs Jurisdictional Government CWA State Structures discharging into WBID? Structure permit? Numeric TP discharge limit in permit EPA 4-part test station? Soil TP > 500 mg/kg Annual SW TP > 15 ppb annual Catta

prese

EMAP 

WBIDS WITHIN EVERGLADES PROTECTION AREA 

LOXAHATCHEE NATIONAL WILDLIFE REFUGE 3252B DOI - USFWS Florida 

G-300, G-301, STA1E, STA1W 

NPDES, EFA;G300, G301 No No Impacted 3 YES YES Some 

3252D DOI - USFWS Florida None NA NA Impacted 1 YES YES Domina3252 DOI - USFWS Florida None NA NA Unimpacted 8 No No No 3252G DOI - USFWS Florida ACME Non-ECP No 

Impacted 2; Unimpacted 2 - YES Some 

3252E DOI - USFWS Florida None NA NA Unimpacted 4 Some No Some 3252H DOI - USFWS Florida None NA NA NA NA NA NA WATER CONSERVATION AREA 2 3265G Florida Florida STA2, S-10s 

NPDES, EFA No Impacted 3 YES YES Domina

3265H Florida Florida None NA NA Unimpacted 5 Some No Some 3265F Florida Florida S-7, STA2 

NPDES, EFA No No Some No data Some 

3272 Florida Florida 

S-144, S-145, S-146 Non-ECP No No No No data Some 

WATER CONSERVATION AREA 33268H Florida Florida 

S-11s, S-7, STA3/4 

NPDES, EFA No 

Unimpacted 3; Impacted 1; gap in north YES YES 

3268I Florida Florida S-8 

NPDES, EFA No Impacted 2 YES YES YES 

3268G Florida Florida None NA NA Unimpacted 4 Some No No 3268F Florida Florida S-9 Non-ECP No No No No data Some 3268J Florida Florida S-9 Non-ECP No 

Unimpacted 3; gap in north Some No data Some 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

50 

WBIDs Jurisdictional Government CWA State Structures discharging into WBID? Structure permit? Numeric TP discharge limit in permit EPA 4-part test station? Soil TP > 500 mg/kg Annual SW TP > 15 ppb annual Catta

presen

EMAP UF 

EVERGLADES NATIONAL PARK 3289J 

DOI - NPS, Miccosukee Tribe 

Florida; Miccosukee Tribe 

S-12A-D, S333, S-355AB No No NA Some No marsh data; S!2s No Some 

3289 DOI - NPS Florida S-332s Non-ECP No NA Some No No 3289K DOI - NPS Florida S-332s NA No No No 3303 DOI - NPS Florida S-18C, S-197 Non-ECP No NA Some No No 3261B DOI - NPS Florida None NA NA NA NA NA 

WBIDS DISCHARGING INTO THE EVERGLADES PROTECTION AREA 

FROM EAA (NORTH) 3233 NA Florida NA NA NA NA 3238E NA Florida NA NA NA NA 3238 NA Florida NA NA NA NA 3244 NA Florida NA NA NA NA 3247 NA Florida NA NA NA NA 3249 NA Florida NA NA NA NA 3248A NA Florida NA NA NA NA 3252A NA Florida NA NA NA NA 3254 NA Florida NA NA NA NA 3253 NA Florida NA NA NA NA 3248 NA Florida NA NA NA NA 3263 NA Florida NA NA NA NA 3263A Florida Florida NA NA NA NA 3260B Florida Florida NA NA NA NA 3250 NA Florida NA NA NA NA 3251 NA Florida NA NA NA NA 3260 NA Florida NA NA NA NA FROM WEST 3255 NA NA NA NA NA 3260A NA NA NA NA NA 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

51 

WBIDs Jurisdictional Government CWA State Structures discharging into WBID? Structure permit? Numeric TP discharge limit in permit EPA 4-part test station? Soil TP > 500 mg/kg Annual SW TP > 15 ppb annual Catta

presen

EMAP UF 

3266 

Miccosukee Tribe, Seminole Tribe 

Florida, Miccosukee Tribe, Seminole Tribe NA NA NA NA 

3267 NA 

Seminole Tribe, Florida NA NA NA NA 

3269 DOI - NPS 

Florida, Miccosukee Tribe, Seminole Tribe NA NA NA NA 

3261B DOI - NPS 

Florida, Miccosukee Tribe NA NA NA NA 

FROM EAST 3252C Florida NA NA NA NA 3252F NA Florida NA NA NA NA 3264 NA Florida NA NA NA NA 3275 NA Florida NA NA NA NA 3277C NA Florida NA NA NA NA 3277 NA Florida NA NA NA NA 3277B NA Florida NA NA NA NA 3280 NA Florida NA NA NA NA 3279 NA Florida NA NA NA NA 3301 NA Florida Non-ECP NO NA NA NA NA 3303A NA Florida Non-ECP NO NA NA NA NA 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

52 

APPENDIX B: Draft 2006 impairment determinations by FDEP 

 

FDEP 2006 draft Group 5 verified list impairment determinations for phosphorus. Red indicates 

that the waterbody is impaired and a TMDL is required, green indicate that the waterbody is 

attaining all designated uses. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

53 

 

 

FDEP 2006 draft Group 5 verified list impairment determinations for dissolved oxygen. Red 

indicates that the waterbody is impaired and TMDL is required, green indicate that the 

waterbody is attaining all designated uses. Grey indicates insufficient data to make a 

determination, yellow indicates waterbody is potentially impaired. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

54 

APPENDIX C: Indicators of phosphorus impairment in the EPA. 

Cattail presence throughout the EPA 2004-2005. Data are from the University of Florida, SFWMD 

and USEPA R-EMAP (Scheidt and Kalla 2007). 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

55 

Soil TP concentration throughout the EPA 2004-2005. Data are from the University of Florida, 

SFWMD and USEPA R-EMAP (Scheidt and Kalla 2007). 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

56 

APPENDIX D: Calculation of current water quality conditions 

Discharges into the Refuge at WBID 3252B. Acre-feet are times 1000. Data are from Table 3. 

WY G300+G301 untreated G251 STA1W outflow G310 STA1W outflow S362 STA1E outflow 

Flow TP load FWMC Flow TP load FWMC Flow TP load FWMC Flow TP load FWMC Flow 

(ac-ft) (mt) (ppb) (ac-ft) (mt) (ppb) (ac-ft) (mt) (ppb) (ac-ft) (mt) (ppb) (ac-ft) 

2002 11 1.6 118 7 0.2 19.8 261 12 37.3 279.0 2003 10 2.5 202 97 5.5 44.1 499 33.4 54.2 606.0 2004 17 3.1 148 55 3 44.2 243 14.1 46.9 315.0 2005 69 27 317 63 7.8 100.4 320 38.7 97.8 15.9 7.6 387.3 467.9 2006 47 14 242 34 4.5 107.4 104 14.7 115.1 40.54 7.3 145.7 225.5 

Average 378.7 FWMC = flow-weighted mean concentration. * FWMC is weighted by structure flow. Discharges at S-7 into WBID 3265B. Data are from Table 4. 

WY S-7 to 9/3/04 S-7 after 9/3/04 Tota

 Flow TP load FWMC Flow TP load FWMC Flow TP load A (1000 ac-ft) (mt) (ppb) (1000 ac-ft) (mt) (ppb) (1000 ac-ft) (mt) 

2002 98 5.8 47.8 98.0 5.8 2003 143 9.6 54.5 143.0 9.6 2004 156 8.6 44.5 156.0 8.6 2005 132.89 3.4 20.8 176.8 2.6 11.8 309.7 6 2006 456.7 10.8 19.2 456.7 10.8 

Average 232.7 8.16 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

57 

Discharges from ACME basin B (WBID 3252C). 

Water Year TP Load (mt) Flow-weighted TP (ppb) Flow (1000 ac-ft) 

 ACME 1 ACME 2 Total ACME 1 ACME 2 Average ACME 1 ACME 2 Total 

2002 1.7 3.3 5 89 152 120.5 16 18 34 G2003 0.9 1.4 2.3 80 117 98.5 9 9 18 P2004 0.9 1.2 2.1 72 101 86.5 10 10 20 2005 2 2.9 4.9 133 212 172.5 12.3 11.2 23.5 2006 1.4 1.8 3.2 80 116 98 14.2 12.8 27 

Average 3.52 115.2 24.5

FWMC = flow-weighted mean concentration. TP conditions in EAA WBIDs 

 3260 (S-8) 3263 (S-7) 3252A (Knight's Farm Field 1) 

Water 

Year TP load FWMC AW FWMC* TP load FWMC AW FWMC* TP load FWMC AW FWMC* 

 (mt) (ppb) (ppb) (mt) (ppb) (ppb) (mt) (ppb) (ppb) 

2002 105.7 63.3 82.8 74.3 120.7 131.7 Sievers 2003 78.5 55.1 79 77.5 160.4 150.3 McGin2004 61.1 48.7 72.7 72.8 135 129.8 McGin2005 23.6 88.6 59.9 35.7 92 98.7 56.2 203.3 200.9 Pescato2006 46.7 125.8 86.3 54.2 123.2 145.7 49.5 204.8 227.5 Van H

Average 35.2 91.9 62.7 45.0 89.9 93.8 52.9 164.8 168.0* AW FWMC = Area weighted flow-weighted mean concentration. For example, TP concentration at a discharge from a 2

weighted ten times the TP concentration for a 2000 acre farm
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

58 

APPENDIX E: PLOAD model, EMC values and results 

Average annual non-point source loads of nutrients were estimated using a spreadsheet based on 

EPA’s Simple Method formula from the BASINS PLOAD model (EPA, 2001): 

LP = Σu (P * PJ* RVu * Cu* Au * 2.72 / 12) 

Where: LP = Pollutant load, lbs 

P = Precipitation, inches/year 

PJ = Ratio of storms producing runoff (default = 0.9) 

RVu= Runoff Coefficient for land use type u, inches of runoff/inches of rain 

RVu=0.05 + (0.009 * Iu); Iu = percent imperviousness 

Cu = Event Mean Concentration for land use type u, milligrams/liter 

Au = Area of land use type u, acres 

This method calculates nonpoint source loadings for nutrients as the product of the water quality 

concentration and runoff water volume associated with certain land use practices. An annual 

average rainfall of 50 inches was used. The default ratio of 0.9 for storms producing runoff was 

used. Land use data entered into the spreadsheet were based on the SFWMD land use/cover features 

categorized according to the Florida Land Use and Cover Classification System (FLUCCS). Event 

Mean Concentrations (EMCs) for each land use type in Florida were compiled by Harper and Baker 

(2003), and are provided below. 1999 land use was used for WBIDs 3260 and 3263, and 2004 land 

use was used for 3252A and 3252C. 
Everglades – Nutrient Total Maximum Daily Load US EPA Region 4 September 2007 

59 

PLOAD EMC values 

FLUCCS 

ID Land Use Total P (mg/L) 

1000 Urban Open 0.09 

1100 Low Density Residential 0.09 

1200 Medium Density Residential 0.09 

1300 High Density Residential 0.09 

2000 Agriculture 0.09 

3000 Rangeland 0.09 

4000 Forest/Rural Open 0.046 

5000 Open Water 0.07 

6000 Water/ Wetlands 0.09 

7000 Barren land/Transition 0.09 

8000 Communication and 

Transportation 0.09 

PLOAD TMDL condition results

 

WBID TP (mg/l) TP (lb/yr) 

3260 0.089 5467 

3263 0.088 3915 

3252A 0.087 1468 

3252C 0.082 127