Final 3/18/09



## FLORIDA DEPARTMENT OF ENVIRONMENTAL PROTECTION

Division of Environmental Assessment and Restoration



### CENTRAL DISTRICT • INDIAN RIVER LAGOON BASIN



# TMDL Report

Nutrient and Dissolved Oxygen TMDLs

for the Indian River Lagoon and Banana River Lagoon

X ueqing Gao

March 2009ii Florida Department of Environmental Protection TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 2009



# Acknowledgments

This TMDL report was developed based on the Pollutant Load Reduction Goal (PLRG) for seagrass restoration in the Indian River Lagoon (IRL) and Banana River Lagoon

, created by the St. Johns River Water Manag ement District (SJRWMD)

, and the Total Maximum Daily Loads (TMDLs) for the Northern and Central I RL and Banana River Lagoon

, developed by the U .S.

Environmental Protection Agency (EPA). We would like to sincerely thank Joel Steward (SJRWMD) and Whit n e y Gr een (SJRWMD), who developed the seagrass PLRG

, Dr. Margret Lasi, who provided great helps on the atmospheric deposition data, and Elizabeth Belk (EPA) and Dan Scheidt (EPA) , who developed the nutrient TMDLs for some of the lagoon segments

included in this report

. T he y offered many valuab le comments and suggestions to help in the

understand ing of the se lagoon system s, explained many modeling details, and also provided a large amount of information and data needed to generate the TMDLs.

We would also like to thank Dr. Margret Lasi (SJRWMD), who provided detailed analyses of the nutrient loadings from direct atmospheric deposition. Special thanks also go to Chris tianne

Ferraro from the Central District Office

, Florida Department of Environment P rotection ( Department) , who provided assistance in developing the wasteload allocation for domestic wastewater facilities, helped us interpret wastewater permitting rules

, and provided the history of

the wastewater facilities located in the watersheds . We would also like to thank Marc Harris, Mike Hatcher, and Allen Hubbard from the Department’s Industrial Wastewater Section for their help in developing the wasteload allocations for industrial wastewater facilities.

Editorial assistance provided by Jan Mandrup

- Poul sen and Linda Lord

For additional information on the watershed management approach and impaired waters

in the I RL Basin, contact Amy Tracy Florida Department of Environmental Protection Bureau of Watershed Management Watershed Planning and Coordination Se ction 2600 Blair Stone Road, Mail Station 3565
Tallahassee, FL 32399

- 2400

Email: Amy.Tracy@dep.state.fl.us

Phone: ( 850 ) 245

– 8506 Fax: (850) 245

– 8434

Access to all data used in the development of this repo rt can be obtained by contacting Xueqing Gao Florida Department of Environmental Protection Bureau of Watershed Management

Watershed Assessment Section 2600 Blair Stone Road, Mail Station 3555 Tallahassee, FL 32399

- 2400

Email: Xueqing.Gao@dep.state.fl.us Phone: (850) 245

– 8464 Fax: (850) 245

– 8434TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection iii 

# Table of Contents

**Chapter 1: INTRODUCTION**

**________________________________ ____________**  **1**

1.1 Purpose of Report

________________________________ ____________ 1

1.2 Identification of Waterbody

________________________________ _____ 1

1.3 Background

________________________________ _________________ 3

**Chapter 2: DESCRIPTION OF WATER QUALITY PROBLEM**

**__________________ 5** 

2.1 Statutory Requirements and Rulemaking History

___________________ 5

2.2 Information on Verified Impairment

______________________________ 5

**Chapter 3. DESCRIPTION OF APPLICABLE WATER QUALITY STANDARDS**

**AND TARGETS**

**________________________________ ____________**  **10**

3.1 Classification of the Waterbody and Criteria Applicable to the

TMDL

________________________________ _____________________ 10

3.2 Applicable Water Quality Standards and Numeric Water Quality Target

________________________________ _____________________ 11

**3.2.1 Interpretation of Narrative Nutrient Criterion**

**________________ 11** 

3.2.1.1 Establishing Nutrient Loading Targets for the IRL and Banana River Lagoon

________________________________ __ 11


### 3.2.2 Applicable Water Quality Standard for DO Concentration

**______ 17** 

**Chapter 4: ASSESSMENT OF SOURCES**

**________________________________ 19** 

4.1 Types of Sources

________________________________ ____________ 19

4.2 Potential Sources of Pollutants in the IRL and Banana River Lagoon Watersheds

________________________________ _________ 19

**4.2.1 Point Sources**

**________________________________ __________**  **19**

4.2.1.1 Wastewater Point Sources

_______________________________ 19

4.2.1.2 Municipal Separate Storm Sewer System P ermittees

_________ 27


### 4.2.2 Nonpoint Sources

**________________________________ ______**  **29**

4.2.2.1 Land Uses

________________________________ ____________ 31

4. 2.2.2 Nonpoint Source TN and TP Loadings from the Watersheds Draining into the IRL and Banana River Lagoon

________________________________ ______________ 34

4.2.2.3 TN and TP Loadings from Atmospheric Deposition Directly onto the Surface of the IRL and Banana River Lagoon

________________________________ ______________ 40



### Chapter 5: DETERMINATION OF ASSIMILATIVE CAPACITY

**_________________ 45** 

5.1 Overall Approach

________________________________ ____________ 45

**Chapter 6: DETERMINATION OF THE TMDL**

**______________________________ 49** TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection iv 

### 6.1 Expression and Allocation of the TMDL

__________________________ 49

6.2 Load Allocation

________________________________ _____________ 52

6.3 Wasteload Allocation

________________________________ _________ 54

**6.3.1 NPDES Wastewater Discharges**

**___________________________ 54** 

**6.3.2 NPDES Stormwater Discharges**

**___________________________ 63** 

6.4 Margin of Safety

________________________________ _____________ 63

6.5 Recommendations for Further Studies

__________________________ 64

**Chapter 7: NEXT STEPS: IMPLEMENTATION PLAN DEVELOPMENT AND**

**BEYOND**

**________________________________ __________________**  **65**

7.1 Basin Management Action Plan

________________________________ 65

**References 66** 

**Appendices**

**________________________________ _________________________**  **70**

Appendix A: Background Information o n Federal and State Stormwater Programs

________________________________ __________________ 70TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection v 

# List of Tables

**Table 1.1. WBIDs and Parameters Addressed in This TMDL Report**

**___________ 3** 

**Table 2.1. Summary of Nutrient**  **Data in the Verified Period for WBIDs**

**2963B and 2963F**

**________________________________ ____________**  **8**

**Table 2.2. Summary of DO Monitoring Data in the Verified Period for** 

**WBIDs 2963D and 2963F**

**________________________________ ______**  **9**

**Table 3.1. Range of Seagrass Median Depth** 

**- Limit**  **Targets for the Three Sublagoons** 

**________________________________ _______________**  **12**

**Table 3.2. Nutrient Loading Targets for Surface Water Nonpoint and Point**  **Sources Lagoonwide, and for the Three Sublagoon Systems (Steward and Green 2006)** 

**________________________________ ___**  **16**

**Ta ble 4.1.**  **Point Source Facilities that Discharge into the IRL and Banana River Lagoon** 

**________________________________ ______________**  **23**

**Table 4.2. Long** 

**- Term Annual Average TN Loadings from NPDES** 

**** **Permitted Facilities (2000**

**– 05)** 

**________________________________ 24** 

**Table 4.3. Long** 

**- Term Annual Average TP Loadings from NPDES** 

**** **Permitted Facilities (2000**

**– 05)** 

**________________________________ 24** 

**Table 4.4. TP Concentration of the Boiler Blowdown Discharge for the**  **Reliant Energy Indian River Power Plant**

**_______________________ 26** 

**Table 4.5.**  **MS4 Permittees Affected by TMDLs in the IRL and Banana River Lagoon Watersheds** 

**________________________________ ___**  **28**

**Table 4.6. Land Use Distribution (in acres) in the IRL and Banana River**  **Lagoon Watersheds**

**________________________________ ________**  **32**

**Table 4.7. Perce**  **nt Land Use Distribution in the IRL and Banana River Lagoon Watersheds** 

**________________________________ ________**  **33**

**Table 4.8. Annual Rainfall (inches) (2000**

**– 05) and 30** 

**- Year Long** 

**- Term**  **Annual Average Rainfall (1975**

**– 2005) at Five National Weather** 

**Service Stations Used in the Development of This TMDL (EPA**  **2007)**

**________________________________ _____________________**  **39**

**Table 4.9. Nonpoint Source Loadings of TN and TP from the IRL and**  **Banana River Lagoon Watersheds**

**____________________________ 40** 

**Table 4.10. Per** 

**- Acre Nonpoint Source Loadings of T**  **N and TP from the IRL and Banana River Lagoon Watersheds** 

**_________________________ 41** 

**Table 4.11. Surface Areas of the IRL and Banana River Lagoon Segments** 

**_____ 42** 

**Table 4.12. Atmospheric TN and TP Loadings Depositing Directly**  **onto the Surface of the IRL and Banana River Lagoon Segments** 

**___________ 43** 

**Table 4.13a. Total Nonpoint Source TN Loads (lbs/yr) to the IRL and**  **Banana River Lagoon Segments**

**______________________________ 43** 

**Table 4.13b. Total Nonpoint Sour**  **ce TP Loads (lbs/yr) to the IRL and Banana River Lagoon Segments** 

**______________________________ 44** TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection vi 

### Table 5.1. **TN and TP Existing and Target Loadings and Load Reductions Required to Achieve the Target Loadings** 

**_______________________ 46** 

**Table 5.2. TN a**  **nd TP Existing and Target Loadings to Impaired WBIDs and Load Reductions Required To Achieve the Target Loadings** 

**___ 47** 

**Table 6.1a. TN TMDL Components for Nutrient** 

**- Impaired WBIDs of the IRL**  **and Banana River Lagoon Main Stem**

**__________________________ 50** 

**Table 6.1b. TP TMDL Components for Nutrient** 

**- Impaired WBIDs of the IRL**  **and Banana River Lagoon Main Stem**

**__________________________ 50** 

**Table 6.2a. TN TMDL Daily Loads for Nutrient** 

**- Impaired WBIDs of the IRL**  **and Banana River Lago on Main Stem** 

**__________________________ 51** 

**Table 6.2b. TP TMDL Daily Loads for Nutrient** 

**- Impaired WBIDs of the IRL**  **and Banana River Lagoon Main Stem**

**__________________________ 51** 

**Table 6.3a. Required Percent Reductions of TN and TP Loads, by WBID, To**  **Achieve Restoration Targets (Excluding Atmospheric Deposition)** 

**________________________________ ________________**  **53**

**Table 6.3b. Required Percent Reductions of TN and TP Loads, by WBID, To**  **Achieve Nonpoint Source Loading Targets (Including Atmospheric Deposition)** 

**________________________________ ____**  **53**

**Table 6.4a. Permitted Annual TN Limits, Discharges, and WLAs for**  **Facilities and TMDLs for Each Lagoon Segment**

**_________________ 55** 

**Table 6.4b. Permitted Annual TP Limits, Discharges, and WLAs for** 

**Facilities and TMDLs for Eac h Lagoon Segment** 

**_________________ 57** TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection vii 

# List of Figures

**Figure 1.1. Location of the IRL Basin**

**________________________________ ____**  **2**

**Figure 2.1. Seagrass Depth Medians for Lagoon Segments Compared with** 

**Full**

**- Restoration Target**  **s: IR1**

**– IR21 Represent IRL Segments,** 

**and BR1**

**– BR7 Represent Banana River Segments. These**  **Segments Were Delineated by the SJRWMD (EPA 2007).**

**___________ 6** 

**Figure 3.1. Location of the North IRL, Central IRL, and Banana River**  **Lagoon, and Fur ther Segmentation of the IRL and Banana River**  **Lagoon Systems (Steward and Green 2006)**

**_____________________ 13** 

**Figure 4.1. NPDES** 

**- Permitted Facilities Located in the IRL and Banana**  **River Lagoon Watersheds**

**________________________________ ___**  **22**

**Figure 4.2. PLSM Estimated Versus Measured Loads for Four Creeks in**  **the IRL Watershed (Green and Steward 2003)**

**___________________ 30** 

**Figure 4.3. Major Land Uses in the North IRL Watershed** 

**____________________ 35** 

**Figure 4.4. Major Land Uses in the**  **Central IRL Watershed**

**__________________ 36** 

**Figure 4.5. Major Land Uses in the Banana River Lagoon Watershed** 

**_________ 37** 

**Figure 4.6. IRL and Banana River Lagoon Watershed Delineation and** 

**Locations of National Weather Service Stations** 

**_________________ 38** 

**Figure 5.1. Spatial Relationship Between the Department’s WBID**  **Boundaries and the SJRWMD’s Segment Boundaries**

**____________ 48** TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection viii 

# Websites

**Florida Department of Environmental Protection, Bureau of Watershed Management** 

Total Maximum Daily Load Program

http://www.dep.state.fl.us/water/tmdl/index.htm

Identification of Impaired Surface Waters Rule

http://www.dep.state.fl.us/legal/Rules/shared/62

- 303/62

- 303.pdf

STORET Program

http://www.dep.state.fl.us/water/storet/index.htm

2008 305(b) Report

http://www.dep.state.fl.us/water/docs/2008_Integrated_Report.pdf

Criteria for Surface Water Quality Classifications

http://www.dep.state.fl.us/water/wqssp/classes.htm

Basin Status Reports and Water Quality Assessment Reports

http://www.dep.state.fl.us/water/tmdl/stat_rep.htm



## U.S. Environmental **Protection Agency**

Region 4: Total Maximum Daily Loads in Florida

http://www.epa.gov/region4/water/tmdl/florida/

National STORET Program

http://www. epa.gov/storet/TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 1 

# Chapter 1: INTRODUCTION

1.1 Purpose of Report

This report presents the nutrient and dissolved oxygen (DO) Total Maximum Daily Load s (TMDL s ) for the Indian River Lagoon (IRL) and Banana River Lagoon

, with in the larger I RL

Basin. Th ese waters were verified as impaired due to excessive amount s of phosphorus and nitrogen in the system

, based on evidence of a decrease in seagrass distribution provided by

the St. Johns River Water Management District (SJRWMD) and low DO , as verified through water quality assessments

. These waters were added to the Verified List of impaired waters for

the I RL Basin by Secretarial Order on December 12 , 2007

. T he purpose of these TMDL s is to establish the allowable loadings of phosphorus and nitrogen to the I RL and Banana River Lagoon that would restore the se waterbodies such that they meet their applicable water quality

criteri a for nutrients and DO

.



### 1.2 Identification of Waterbody

The IRL Basin is a 156

- mile

- long estuary located on Florida ’s e ast c oast

. T here are six coastal

Florida c ounties in the natural IRL watershed : from north to south, these are Volusia, Brevard, Indian River, St. Lucie, Martin, and Palm Beach C ounties

. The I RL watershed described in this TMDL report includes only part of the large r IRL Basin

, which starts just south of Ponce De Leon Inlet in the north, covers the southeast ern corner of Volusia County and east ern portions of Brevard and Indian River Counties, and ends just north of the Fort Pierce Inlet . The majority

of the basin area is located between Interstate Highway 95 (I

- 95) and the central portion of

Florida’s Atlantic coastline ( Figure 1.1 )

. T he basin is well

- developed

, with close to 30 percent

of the nonwater areas occupied by urban and built

- up land. It contains a bout 2 0 municipalities and townships, including New Smyrna Beach, Titusville, Cocoa Beach, Melbourne, Palm Bay,

and Vero Beach.

T he three interconnected lagoons in the IRL B asin are commonly referred to as Mosquito Lagoon, I RL , and Banana River Lagoon. Circu lation in these lagoons is influenced by winds, freshwater inflows from tributaries, and tidal exchange via direct connections to the Atlantic Ocean. Other than stream inflows, freshwater inflows also come from direct overland runoff, drainage canals, gro und water seepage, and rainfall directly on to the surface of these lagoons.

The Mosquito and Banana River Lagoon systems have relatively small stream inflows of fresh water and poor flushing

. Mosquito Lagoon has one inlet, Ponce De Leon, and the Banana River Lagoon has an intermittent navigational connection to the ocean via P ort Canaveral. The I RL has comparatively larger stream inflows, particularly in its central and southern regions, but it is also poorly flushed, especially in its northern half. There is some improvement in flus h ing in the southern half because of the presence of four oceanic inlets: Sebastian, Ft. Pierce, St. Lucie, and Jupiter.

The entire I RL system is a nationally renowned aquatic ecosystem that supports tremendous

biodivers ity and also provides recreational and commercial fishing resources. It was designated in the 1987 Surface Water Improvement and Management (SWIM) Act as a priority waterbodyTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 2 Figure 1.1. Location of the I RL Bas inTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 3 in need of restoration and special protection. Major problems included the loss of or alteration

of 75 percent of the lagoon’s salt marsh and mangrove wetlands, excessive freshwater discharges into the central lagoon due to drainage improvements in co astal watersheds and the diversion of floodwaters from the St. Johns River floodplain, and discharges of pollutant

- laden wastewater and stormwater into the lagoon. Excessive fresh water degraded hard clam habitat

and seagrass coverage densities

. P ollutan ts in discharges exacerbated turbidity levels and promoted alga l growth, contributing to the destruction of seagrass beds.

In 1991, the IRL became a part of the National Estuary Program (NEP). Efforts under the IRL

P rogram at the S JRWMD focus on improv ing water and sediment quality to restore or enhance seagrass and on rehabilitating impacted wetlands to recover as many of their natural functions as possible ( http://www.sjrwmd.com/pro grams/indianriverlagoon.html )

.

For assessment purposes, the Department has divided the I RL Basin into water assessment polygons with a unique w ater b ody id entification (WBID) number for each watershed or stream

reach. This TMDL report addresses nutrient and DO impairments in the WBIDs that are parts of

the main stem of the I RL and Banana River Lagoon. Table 1.1 summarizes the WBIDs covered in this TMDL report and the pa rameters of concern for each seg ment

.

Table 1.1. WBIDs and Parameters Addressed in T his TMDL Report

WBID Waterbody Name Parameters of Concern

3044A Newfound Harbor Nutrient s (Seagrass)

3057A Banana River below Mathers Nutrient s (Seagrass)

3057B Banana River above 520 Causeway Nutrient s (Seagrass)

3057C Banana River above Barge Canal N utrient s (Seagrass)

2963A Indian River above Sebastian Inlet Nutrient s (Seagrass)

2963B Indian River above Melbourne Causeway Nutrient s (Seagrass), Nutrients (Chl orophyll a [Chla] )

2963C Indian River above Melbourne Causeway Nutrient s (Seagrass)

2963D Indian River above 520 Causeway Nutrient s (Seagrass) and DO

2963E Indian River above NASA Causeway Nutrient s (Seagrass)

2963F Indian River above M. Brewer Nutrient s (Seagrass), Nutrients (Chla)

, and DO

5003 B South Indian River Nutrient s (Seagrass)

500 3C South Indian River Nutrient s (Seagrass)

5003D South Indian River Nutrient s (Seagrass)



### 1.3 Background

This report was developed as part of the Department’s watershed management approach for restoring and protecting state waters and addressing TMDL P rogram requirements. The watershed approach, which is implemented using a cyclical management process that rotates through the state’s 52 river basins over a 5

- year cycle , provides a framework for implementing the TMDL Program

– related requirements of the 1972 federal Clean Water Act and the Florida Watershed Restoration Act ( FWRA )

.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 4 A TMDL represents the maximum amount of a given pollutant that a waterbody can assimilate and still meet water quality standards, including its applicable water quality criteri a and its designated uses. TMDLs are developed for waterbodies that are verified as not meeting their water quality standards, and provide important water quality restoration goals that will guide

restoration activities.

The U.S. Environmental Protection Agency (EPA) finalized a n utrient and DO TMDL report for

the IRL and Banana River Lagoon in 2007. The report addresse d the lagoon segments that

we re on the EPA’s 1998 303(d) list of impaired waters , which only covers portion s of the main

stems of the I RL and Banana River Lagoon. The EPA report also covers the nutrient and DO impairments in several tributaries that discharge into the I RL

, and was based on the nutrient targets developed to protect seagrass communities in the main stem s of these lagoon syst ems

.

In contrast, t he nutrient and DO TMDLs in this TMDL report address only the nutrient and DO impairments for the main stems of the I RL and Banana River Lagoon. No tributar ies are included because the Department believe s that the nutrient targets for protect ing the tribu taries may be different from those established for protecting the main stem segments. Therefore, the Department will publish tributary nutrient and DO TMDLs in a separate report in the near future.

In addition, because the entire ma in stem of the Banana River Lagoon and all the I RL main stem segments north of the southern boundary of Indian River County were listed as impaired

for nutrient s on the Department’s Verified List, this TMDL report covers all these main stem
segments

, inste ad of just those on the EPA’s 1998 303(d) list. The implementation of th e
TMDL s will appl y to the watershed that drains to all these lagoon segments.

In addition to these differences, the final TMDLs in this report also include load estimations for

direc t atmospheric deposition that were not included in the EPA’s 2007 TMDL report , as well as

w asteload allocations (WLA s ) for two more point source dischargers that were not in the EPA
report.

This TMDL report will be followed by the development and impleme ntation of a Basin Management Action Plan, or BMAP, to reduce the amount of nutrients that caused the verified impairment of the I RL and Banana River L agoon . These activities will depend heavily on the active participation of the SJRWMD, local governments , businesses, and other stakeholders. The Department will work with these organizations and individuals to undertake or continue reductions in the discharge of pollutants and achieve the established TMDLs for impaired

waterbodies.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 5 

# Chapter 2: DESCRIPTI ON OF WATER QUALITY

PROBLEM

2.1 Statutory Requirements and Rule m aking History

Section 303(d) of the Clean Water Act requires states to submit to the EPA a list of surface waters that do not meet applicable water quality standards (impaired waters) and establish a TMDL for each pollutant source in each of these impaired waters on a schedule. The Department has developed these lists, commonly referred to as 303(d) lists, since 1992. The list of impaired waters in each basin is also required by the Florida Watershed Restoration Act ( FWRA

, Subsection 403.067[4]

, Florida Statutes [F.S.]), and the list is amended annually to include updates for each basin statewide.

Florida’s 1998 303(d) list included 16 waterbodies in the IRL Basin. However, the FWRA (Sectio n 403.067, F.S.) stated that all previous Florida 303(d) lists were for planning purposes only and directed the Department to develop, and adopt by rule, a new science

- based methodology to identify impaired waters. After a long rulemaking process, the Env ironmental Regulation Commission adopted the new methodology as Chapter 62

- 303, Florida Administrative Code (F.A.C.) (Identification of Impaired Surface Waters Rule, or IWR), in April

2001 ; the rule was modified in 2006. The list of waters for which impairments have been verified using the methodology in the IWR is referred to as the Verified List.



### 2.2 Information on Verified Impairment

As defined in the IWR, the primary assessment index for estuary nutrient condition is c hla

concentration . An estuary ca n be listed for nutrient impairment if , during the verified period of

an assessment (1999 through 2006 for the IRL Basin) , its annual average chla concentration

exceeds the 11 micrograms per liter ( μg/L ) threshold in any given year

, or the 5

- year rolling

h istoric al minimum annual average concentration by more than 50 percent in 2 consecutive years. Based on these thresholds, the majority of the WBIDs in the I RL and Banana Ri v er Lagoon were assessed as not impaired for nutrient s

.

However, the IWR also al lows the use of information other than chla concentration s to verify

nutrient

- based impairment , including algal blooms, excessive macrophyte growth, a decrease in the distribution (either in density or areal coverage) of seagrasses or other submerged aquat ic vegetation, changes in algal species richness, and excessive diel oxygen swings. The verification of the nutrient impairment for the main stem segments of the I RL and Banana River Lagoon ( Table 1.1 ) was primarily based on the information provided by th e SJRWMD that

seagrass coverage s in these lagoon segments were depressed compared with the seagrass target depth limit ( Figure 2.1 )

.

Results from several studies have indicate d that phosphorus and nitrogen loadings into the I RL
system are among the majo r factors control ling seagrass coverage. For example, Steward and

Green ( 2005 ) established that seagrass depth

- limit depression in the IRL was mainly caused by elevated light attenuation. Studies by Gallegos (1994) and Steward et al. (2003) indicated tha t

total suspended solids (TSS), water color, and chla concentration were the major factorsTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 6 Figure 2.1

. Seagrass Depth Medians for Lagoon Segments Compared with

Full

- R estoration Targets : IR1

– IR21 Represent I RL Seg ments

, and BR1

– BR7 Represent Banana River Segments . These

Segments Were Delineated by t he SJRWMD (EPA 2007)

.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 7 attenuating light in the lagoon. Hanisak (2001) showed a strong correlation between chla and total phosphorus (TP) concentrations in the lagoo n, suggesting that phosphorus is one of the major causative pollutants for the elevated chla concentration s . In addition, Hanisak’s studies showed a strong negative correlation between nutrient concentration s in the lagoon and salinity, suggesting that th e watershed might be the major source of nutrient s in the lagoon.

That study was followed by the work of Steward and Green (2006

, 2007) , which revealed significant correlation s between watershed nutrient loadings (TP and total nitrogen [ TN ] ) and

seagras s depth limits. Trefry and Feng (1991) and Phlips et al. (2002) conducted other studies that linked the imbalance of lagoon aquatic communities to watershed nutrient inputs. All these studies indicated that nutrients play an important role in controlling seagrass abundance and

that the majority of these nutrients were contributed by the watershed of the lagoon system

.

S everal segments of the I RL and Banana River Lagoon were also listed for nutrient impairment

based on elevated chla concentration s and low DO. Table 2. 1 lists the nutrient information for WBID 2963B (Indian River above Melbourne Causeway ) and WBID 2963F (Indian River above M. Brewer). Table 2. 2 lists data related to the DO impairment for WBID 2963D (Indian River

above 520 C au seway) and WBI D 2963F (Indian River above M. Brewer).

Based on Table 2.1

, WBID 2963B was listed for nutrient impairment based on the observation that annual average chla concentrations in 2001, 2002, and 2005 exceeded the assessment threshold of 11 μg/L. WBID 2963F was listed for nutrient impairment because the annual

average chla concentrations exceeded the assessment threshold of 11 μg/L from 1999 through
2002, and in 2004 and 2005. The median TN/TP ratios for both segments fell between 10 and 30, suggesting that the phytoplankton communities in these water segments are co

- limited by phosphorus and nitrogen.

In addition, WBID 2963D and 2963F were verified for DO impairment based on observations that 770 out of 4,603 samples in WBID 2963D, and 237 out of 952 samples in WBID 2963F,

were lower than the 5.0 milligrams per liter ( mg/L ) assessment threshold. TN concentrations higher than the 1.0 mg/L assessment threshold were observed for both WBIDs, suggesting that elevated nitrogen was the causative pollutant for low DO in these WBIDs ( Table 2.2 ).TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 8 Table 2. 1

. Summary of N utrient D ata in the V erified P eriod for WBID s

2963B and 2963F

WBID Parameter Summary of Observation

2963B (Indian

River

above

Melbourne Causeway) Exceedance of annual chla concentration (11 μg/L) Ex ceeded in 2001, 2002,

and 2005

Range of chla concentration (μg/L) 1.2

– 61.5

Median chla concentration (μg/L) 7.2

Range of TN concentration (mg/L) 0.53

– 2.70

Median TN concentration (mg/L) 1.14

Range of TP concentration (mg/L) 0.02

– 0.25

Median of TP concentration (mg/L) 0.058

Median TN/TP ratio 22.7

Limiting n utrient (s) Nitrogen and phosphorus

co

- limited

2963F (Indian

River

above M.

Brewer ) Exceedance of annual chla concentration (11 μg/L) Exceeded in 1999

– 2002

and 2004

– 05

Range of chla co ncentration (μg/L) 1.0

– 285 .0

Median of chla concentration (μg/L) 5.4

Range of TN concentration (mg/L) 0.33

– 4.82

Median of TN concentration (mg/L) 1.32

Range of TP concentration (mg/L) 0.01

– 0.81

Median of TP concentration (mg/L) 0.04

Median TN/T P ratio 26

Limiting n utrient (s) Nitrogen and phosphorus

co

- limitedTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 9 Table 2. 2

. Summary of DO Monitoring Data in the V erified P eriod for

WBID s 2963D and 2963F

WBID Parameter Summary of

O bservation

2963D (Indian River

above 520 Causeway) Total number of samples 4

, 603

IWR

- required number of exceedances for the V erified L ist 552

Number of observed exceedances 770

Number of observed non exceedances 3

, 833

Number of seasons during which samples were collected 4

Highest DO observation (mg/L) 14.1

Lowest DO observation (mg/L) 0.0

Median DO observation (mg/L) 6.4

Mean DO observation (mg/L) 6.3

Median value for biochemical oxygen demand ( BOD ) observations (mg/L) No BOD

measurements

Median value for 363 TN observations (mg/L) 1.40

Median valu e for 738 TP observations (mg/L) 0.04

Possible causative pollutant by IWR Nitrogen

FINAL ASSESSMENT Impaired

2963F (Indian River

above M. Brewer) Total number of samples 952

IWR

- required number of exceedances for the V erified L ist 114

Number of o bserved exceedances 237

Number of observed nonexceedances 715

Number of seasons during which samples were collected 4

Highest DO observation (mg/L) 11.9

Lowest DO observation (mg/L) 0.1

Median DO observation (mg/L) 5.9

Mean DO observation (mg/L ) 5.6

Median value for 18 BOD observations (mg/L) 2. 1

Median value for 339 TN observations (mg/L) 1.32

Median value for 343 TP observations (mg/L) 0.05

Possible causative pollutant by IWR Nitrogen

FINAL ASSESSMENT ImpairedTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 10 

# Chapter 3. DESCRI PTION OF APPLICABLE WATER

QUALITY STANDARDS AND TARGETS

3.1 Classification of the Waterbody and Criteria Applicable to the TMDL

Florida’s surface waters are protected for five designated use classifications, as follows:

Class I Potable water supplies

Cl ass II Shellfish propagation or harvesting

Class III Recreation, propagation, and maintenance of a healthy, well

balanced population of fish and wildlife

Class IV Agricultural water supplies

Class V Navigation, utility, and industrial use (there are no state waters currently in this class)

The following WBIDs listed in Table 1.1 are Class II waterbodies, with a designated use of shellfish propagation or harvesting:

**•** WBID 2963A (Indian River above Sebastian Inlet );

**•** WBID 2963C (Indian River above Melbour ne Causeway );

**•** WBID 2963F (Indian River above M. Brewer), 5003B (South Indian River ); and

**•** WBID 5003D (South Indian River).

The remaining WBIDs in the table are all Class III waterbodies, with a designated use of recreation, propagation, and maintenance of a healthy, well

- balanced population of fish

and wildlife:

**•** WBID 3044A (Newfound Harbor );

**•** WBID 3057A (Banana River below Mathers );

**•** WBID 3057B (Banana River above 520 Causeway );

**•** WBID 3057C (Banana River above Barge Canal );

**•** WBID 2963B (Indian River ab ove Melbourne Causeway );

**•** WBID 2963D (Indian River above 520 Causeway );

**•** WBID 2963E (Indian River above NASA Causeway ); and

**•** WBID 5003C (South Indian River )

.

These TMDLs address b oth Class II and Class III water quality criteria for nutrients and DO, as applicable.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 11 

### 3.2 Applicable Water Quality Standards and Numeric Water Quality Target

**3.2. 1**  **Interpretation of Narrative Nutrient Criterion**

Florida’s nutrient criterion is narrative only

— i.e., nutrient concentrations of a body of water shall

not be alter ed so as to cause an imbalance in natural populations of aquatic flora or fauna. Accordingly, a nutrient

- related target was needed to represent levels at which an imbalance in flora or fauna is expected to occur. A threshold commonly used for assessing t he nutrient impairment in estuaries is the annual average chla concentration of 11 μg/L , which is defined in

the I WR ( Chapter 62

- 303

, F.A.C

. ). T he IWR also allows the use of o ther information indicating

an imbalance in flora or fauna due to nutrient enric hment, including, but not limited to, algal blooms, excessive macrophyte growth, a decrease in the distribution (either in density or areal coverage) of seagrasses or other submerged aquatic vegetation, changes in algal species
richness, and excessive diel oxygen swings.

As discussed in Chapter 2, most segments along the main stems of the IRL and Banana River

L agoon were not verified for nutrient impairment using the chla threshold. The verified impairments were based on a comparison of the existing seag rass depth limits with the

seagrass full

- restoration targets ( Steward and Green 2006). As both TP and TN are identified as important factors that influence seagrass distribution in these systems ( Trefry and Feng
1991, Gallegos 1994, Hanisak 2001, Phlips e t al. 2002, Steward et al. 2003 ), this TMDL

establishes TP and TN targets to achieve the goal of seagrass restoration

.

3.2. 1 .1 Establishing Nutrient Loading Targets for the I RL and Banana River Lagoon

Nutrient targets for the IRL and Banana River Lagoon for this TMDL report were based on the pollutant load reduction goal (PLRG) developed by the SJRWMD ( Steward and Green 2006). These nutrient targets were established through a three

- step process , as follows :

**1. Establishing the seagrass**  **full**

**- restorati**  **on target**

The s patial variability of the I RL and Banana River Lagoon is well

- documented

. Therefore, different seagrass restoration targets for different parts of the lagoon systems should be

considered. Historically, the lagoon system was divided into th ree sub lagoons

— North IRL

, Central IRL , and Banana River Lagoon

— based on the unique hydraulic characteristics of each part of the system . According to Christian (2004) and Steward and Green (2007) , the entire

Central I RL lie s within 28 kilometer s of either the Sebastian Inlet or Ft. Pierce Inlet, and is much

closer to the inlets than the North I RL and Banana River Lagoon . Consequently, the average flushing rate in the Central I RL is 10 times higher than in the North I RL and 15 times higher than

in the Bana na River Lagoon

. Figure 3.1 shows the location of the three sub lagoons

.

To appropriately address seagrass distribution in different part s of the lagoon system, the three

sub lagoons were further divided into segments ( Fig ure 3 .1 ). These segments were ini tially

created based on the location of 13 causeway bridges that span the I RL and Banana River Lagoon system (Virnstein et al. 2003) , result ing in 21 preliminary segments.

A detailed principle component analysis indicated that salinity and turbidity var iations explained most differences between these segments. Follow

- up cluster and Kriging analyses regroupedTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 12 the segments based on similarities in salinity and turbidity and created a 15

- segment delineation (Sigua et al. 1996). S eagrass target s and

, in tu rn

, nutrient targets were based on segment

specific seagrass depth limits

, and the relationship between seagrass depth limit s and model

simulated TN and TP loadings ( Figure 3.1 )

.

As elevated light attenuation is one of the major factors influencing the ma ximum water depth to which seagrass can grow ( Stewar d et al. 2005), and this in turn determines the total area of seagrass distribution in a lagoon system, seagrass distribution depth limit was used as an index in assessing the extent of seagrass distribut ion. Seagrass depth

- limit data were obtained by comparing historical seagrass maps with the lagoon bathymetry established by Coastal Planning and Engineering, Inc., in 1996. Seagrass maps from 1943, 1986, 1989, 1992, 1994, 1996, and 1999 were used for th is analysis.

Depth measurements closest to a segment’s seagrass deep

- edge boundary were selected using a set of rules that captured only the appropriate bathymetric data and excluded other data that could create erroneous depth limits (e.g., near or wit hin dredged areas and the shallow edges of seagrass beds [ Steward et al. 2005]). No sea

- level rise correction was applied in this analysis because previous studies (Trefry et al. 1990

, Martin et al

. 2004) indicated that the change in bottom elevation of t he lagoon system resulting from sedimentation generally

balances out the sea

- level rise.

The seagrass depth

- limit target for the lagoon was established based on the union of all the seagrass maps available from 1943 through 1999 ( Steward et al. 2005). T he deep

- edge boundary delineating this unified coverage was considered the maximum depth limit that seagrass distribution can reach under the full

- restoration condition. The final depth

- limit targets were established by allowing a 10 percent departure (sh allower) from the full

- restoration depth

limit targets because the State Surface Water Quality Standard (Chapter 62

- 302, F.A.C.) allows a decrease of depth of the compensation point by no more than 10 percent from the natural background condition. The med ian value of the depth

- limit targets for each lagoon segment was used for the analysis to establish the nutrient targets for the lagoon system. Table 3.1 summarizes the ranges of seagrass depth

- limit targets in the three sublagoon segments.

Table 3.1. Range of Seagrass Median Depth

- Limit Targets for the Three

Sublagoons

Sublagoon Median Seagrass Depth Target (meters)

North I RL 1.5

– 1.8

Central I RL 1.2

– 1.7

Banana River Lagoon 1.4

– 1.8TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 13 Figure 3.1

. L ocation of the N orth IRL, C entral IRL, and B anana River Lagoon

, and

Further Segmentation of the I RL and Banana River Lagoon System s ( Steward and Green 2006 ) 

### Segment boundaries

Sub

- basin boundaries 

## North IRL
(IR1

- 3 to IR9

- 11)



## Central IRL
(IR12 to IR21; however,

IR14

- 15 was precluded from the

regression analyses 

### ) 

## Banana River Lagoon (BR1

- 2 to BR 7)

N **Setting Segment Boundaries** Several factors were considered in setting segment boundaries. The primary factor is the presence of 13 causeway bridges

cross ing the Indian River/Banana River (IRBR) between Titusville and Vero Beach. There were apparen t differences in seagrass coverage patterns between several segment pairs separated by causeways. L arge island groupings, cuspate spits, and major tributaries were also considered in setting boundaries. Final segmentation was based on spatial analyses of water quality data : principal component analysis (PCA) and cluster and kriging analyses. PCA identified the principal variables

— turbidity and salinity

— responsible for intersegment variability. The grouping of seagrass segments with similar water qualit y was performed through cluster and kriging analyses of turbidity and salinity (Sigua et al. 1996). The final outcome was an IRBR system divided into 15 segments

, as shown here.



## BR7 IR9

- 11

IR12

IR13

IR16

- 20

IR21 BR1

- 2

BR3

- 5

BR6 ( Newfound Harbor ) 

## IR1

- 3

IR4

IR5

IR6

- 7

IR8

IR14

- 15

Vero

Beach Melbourne

Palm Bay Titusville

Cocoa Beach

Sebastian

Inlet Mosquito Lagoon

Ft. Pierce InletTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 14 **(2) E**  **stablishing the relationship between seagrass depth limit and TN and TP loadings from poin**  **t and nonpoint sources**

Nutrient targets for the I RL and Banana River Lagoon system s were established based on the seagrass depth

- limit targets and correlations between seagrass depth limit s and TN and TP loadings from point and nonpoint sources. TN and TP loadings were the sums of nonpoint and point source loadings. For those segments that had no point source contributors, nonpoint source loadings represented the total loadings.

The SJRWMD simulated n onpoint source loadings using the Pollutant Load Scr eening Model (PLSM) and the Hydrological Simulation Program

– Fortran (HSPF) Model

. For model calibration

purpose s

, the HSPF Model used 1995 land use data

. The calibration of the PLSM was mostly

based on 2000 land use data , while 1990 land use data were us ed to calibrate the model against observed data collected for Turkey Creek/C

- 1 Cana l during the same period

. These

models were built based on the SJRWMD’s 1995 land use information and calibrated against observed gaging data for hydrology in four I RL trib utaries : Crane Creek, C

- 1 Canal of Turkey Creek, South Prong of the Sebastian River, and Briar Creek (Green and Steward 2003

, CDM

2003

, Adkins et al. 2004). These tributaries were selected because they represent the variety of

land uses in the I RL waters hed.

To simulate nonpoint source loadings for a given year, the rainfall of the year and land use information close st to the year under analysis were substituted into the calibrated model s

. For example, to simulate the pollutant loads for 1943, land us e information for 1943 was substituted

into the calibrated model s

, and pollutant loadings for the year were simulated using the 1943

rainfall data. Before March 2000, rainfall data were taken from established National Oceanic and Atmospheric Administratio n (NOAA) National Weather Service stations and were supplemented with data from the SJRWMD ’s hydrological/ meteorological network. After March 2000, rainfall data were derived from Doppler radar

.

During the model calibration, stormwater treatment was a ccounted for by applying loading reduction factors to development s constructed after Florida’s stormwater treatment rules went into effect in 1984. Aerial photo

- interpreted land use maps, circa 1989, were used as a baseline for determining treated versus nontreated development s

. Model

- simulated nutrient loads were comparable to the measured loads for the 4 tributaries listed above

, slightly overpredict ing TN and TP loadings (by about 0.7 percent and 7 percent, respectively ) ( Green and Steward 2003)

. 1

( a

) Typically, TN and TP concentrations in receiving waters are determined by the loading intensity (areal loading) instead of total loading from drainage basins. F or lagoon segments that receive point source discharges, TN and TP loadings from point sources were added to the total loadings that these segments receive. This TMDL includes 16 point sources that discharge into the I RL and Banana River Lagoon. Table 4. 1 lists the facilities and the lagoon segments into which they discharge. Annual loads from the se facilities were

calculated based on flow and concentration measurements retrieved from the Department’s Permit Compliance System D atabase.

The following d ata transformations were conducted before conducting the regression analyses :

1 Detailed descriptions of the PLSM, HSPF M odel, and model calibration can be obtained from Development of a nonpoint source p ollution l oad s cr eening m odel (Mundy and Bergman 1998), HSPF Version 12 user manual (Bicknell et al. 2004), and specific model setups by Green and Steward (2003).TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 15 Therefore, b efore the regression analyses were conducted, the total nutrient loadings from the drainage area of each lagoon segment were converted to areal loadings.

( b

) It has been established that the relationship between nutrient loadings and seagrass depth is no t linear (Steward and Green 2006, Davi e s

- Colley et al.

1993

, Gallegos and Kenworthy 1996) ; therefore

, the areal nutrient loadings were log

- transformed before the regression analysis.

( c

) Seagrass depth limits for the years used to create the regression eq uation were established as percent departures from the seagrass depth

- limit target

.

To conduct the regression analysis, loading estimates for nonpoint sources and point sources,

and the data on seagrass depth limit

, should all be available within the sa me year . The years that met all these requirements were 1943, 1996, 1999, and 2001. Nutrient loading data for point source s were not available for 1943 , but given the limited land use and population in that

year , it was assumed that point source discharg e s into the I RL and Banana River Lagoon were insignificant compared with nonpoint source loading.

According to the SJRWMD, these semi

- log regression analyses utilize d data from all segments except Sebastian Inlet ( IR14

- 15 ) , which was excluded because its hydraulic flushing rate (measured in days) far exceeds the rates of the other segments (measured in months). The higher flushing rate significantly reduces the impact of pollutant loads on seagrass coverage

, in contrast to the apparent impact observed els ewhere in the I RL and Banana River Lagoon

. Pollutant load versus seagrass depth

- limit regression equations were developed lagoonwide

, as well as for each of the sublagoon system s . Nutrient loading estimates from both the HSPF

M odel and the PLSM were eval uated during the regression analyses.

In most case s , loading estimates from the PLSM produced stronger correlation s with the seagrass depth limit than the loading estimates from the HSPF Model

, except for TP for the

North IRL sublagoon segments. Theref ore, the regression equation for TP for the North IRL sublagoon was developed based on HSPF TP loading estimates

, while both the lagoonwide and other sublagoon regression equations were developed based on loading estimates from the

PLSM (Steward and Green 2006

, 2007)

.

**(3) Establishing TN and TP targets based on a** 

**- 10 percent deviation**  **(shoreward) from the seagrass full**

**- restoration targets and the relationship**  **between seagrass depth limit and nutrient loadings.**

After the nutrient loadings

– seagrass depth

- limit regression equations were established, target nutrient loadings for the entire I RL and Banana River Lagoon

, a nd for all the sublagoon
systems

, were estimated by substituting the target seagrass depth limit ( a

- 10 percent departure

from the full

- resto ration condition ) into the regression equations. To avoid underestimating the nutrient loadings by simply back

- transforming the log

- transformed loading rates, according to

the SJRWMD (Steward and Green 2006) a nonparametric method described by Duan (1983)

was used to back

- calculate the target areal loading.

Table 3. 2 shows the target nutrient loadings for nonpoint and point surface water sources for the entire lagoon system

, as well as for the sublagoon systems. The table also shows the

models used for estimating the nutrient loadings from nonpoint sources, the regressionTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 16 coefficient for each regression

, and the probability at which these regression models are statistically significant.

According to the SJRWMD (Steward and Green 2006) and based on Tabl e 3.2 , the sublagoon analyses generally yielded stronger correlation statistics than the lagoonwide analysis. Also, in contrast to a lagoonwide analysis, a sublagoon analysis should generate more realistic loading targets because it better reflects land use and rainfall characteristics specific to the sublagoon drainage areas. Consequently, is the SJRWMD recommend s favoring the sublagoon loading limits over the lagoonwide loading limits in the establishment of loading targets or TMDLs.

T wo WBIDs covered by this TMDL report

— WBID 2963B (Indian River above Melbourne Causeway) and WBID 2963F (Indian River above Melbourne Brewer)

— also had verified impairments for chla

. T he majority of the WBIDs included in this TMDL are listed for nutrient impairments due to seagrass growth depression even when they were not impaired for chla

, suggest ing that the nutrient targets established to address seagrass distribution are more stringent than the nutrient targets set up to address chla concentration. It is therefore expe cted that, once the nutrient targets established for protecting seagrass are achieved, the chla

concentration of these WBIDs should also be controlled.

Table 3. 2. Nutrient Loading Targets for Surface Water Nonpoint and Point

Sources Lagoonwide, and for t he Three Sub lagoon Systems

(Steward and Green 2006)

Lagoon w ide (I RL and Banana River Lagoon combined; excludes Sebastian Segment IR14

- 15

PLSM Regressions TN target loading (pounds per acre per year [ lb s /ac/yr ]) TP target loading (lb s /ac/yr)

Years included in the analyses : 1943, 1996, 1999, and 2001 data 3.34

R 2 = 0.49, p < 0.001 0.546

R 2 = 0.53, p < 0.001

North IRL

PLSM Regressions TN target loading (lb s /ac/yr) TP target loading (lb s /ac/yr)

Years included in the analyses :

1943, 1996, and 1999 data 2.88

R 2 = 0.43, p = 0.006

HSPF Regressions

Years included in the analyses :

1943, 1996, and 1999 data 0.368

R 2 = 0.47, p = 0.003

Central IRL (excludes Sebastian Segment IR14

- 15)

PLSM Regressions TN target loading (lb s /ac/yr) TP target loading (lb s /ac/yr )

Years included in the analyses :

1996, 1999, and 2001 data 2.90

R 2 = 0.87, p<0.001 0.574

R 2 = 0.65, p = 0.001

Banana River Lagoon

PLSM Regressions TN target loading (lb s /ac/yr) TP target loading (lb s /ac/yr)

Years included in the analyses :

1943, 1996, and 1999 data 2.18

R 2 = 0.74, p = 0.001 0.374

R 2 = 0.72, p = 0.001TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 17 

### 3.2. **2 Applicable**  **Water Quality Standard for**  **D O**  **Concentration**

Florida ’s Surface Water Quality Standard s require that the DO concentration for Class II and III

marine water s “shall not av erage less than 5.0 mg/L in a 24

- hour period and shall never be less than 4.0 mg/L. Normal daily and seasonal fluctuations above these levels shall be maintained” (Chapter 62

- 302, F.A.C

. ).

M ultiple environmental factors control DO concentration s in the I RL . Theoretically, the DO concentration in a given waterbody can be influenced by temperature, salinity, flow, water depth, photosynthesis, respiration, sediment oxygen demand (SOD), the oxidation of organic carbon or inorganic reductants, and low DO grou nd water input. Typically, low DO concentrations were observed in the lagoon during the summer months (May to September)

. Occasional DO concentrations lower than 5.0 mg/L were also observed in other months, but

with a much lower frequency

. While t empera ture is an important factor responsible for changes

in DO, saturation DO concentration s under the typical summer water temperature ( 28 0 C) and salinity ( above 3 percent) should still be higher than 6.0 mg/L

, as long as no other chemical and biochemical proc esses are involved ( Clescer l et al. 1999 )

. Therefore, DO co ncentration s lower

than 4 .0 mg/L in the I RL most likely result from factors other than temperature and salinity.

For example, l ow DO ground water input can be an important cause of low DO in ma ny freshwater systems. In the I RL B asin, however, ground water input may not be important in the total water budget because of the existence of a confining layer for the Floridan aquifer ( Martin

et al. 200 4 ). Therefore, the low DO concentration observed in the lagoon could be caused by processes influenced by nutrients, such as elevated respiration due to the excessive populations of both primary producers and grazers at various levels of the food chain, or SOD

.

Excessive amount s of nutrient loading into the lagoon can cause low DO in many different ways. As the chla concentrations in most WBIDs assessed by the Department did not exceed the 11 μg/L threshold, the excessive growth of phytoplankton may not be a major process through which nutrients can inf luence DO concentration s in the lagoon system. Based on a study by Hanisak (2001) in the IRL , the primary productivity of seagrass and epiphytes was much greater ( around 15 to 30 times) than that of phytoplankton and benthic microalgae. His analysis show ed that the mean areal productivity ( grams of carbon fixed by seagrass per square meter per hour [ g C m

- 2 h - 1 ] ) was 0.76 for seagrass, 1.01 for epiphytes, 0.03 for phytoplankton, and 0.05 for benthic microalgae. Therefore, seagrasses and their epiphytes a ccounted for 96
percent of the carbon fixed (41 and 55 percent, for seagrass and epiphytes, respectively).

Nutrients in the water column can stimulate the growth of epiphytes. The e xcessive growth of epiphytic algae on the leaf surface of seagrasses can shield light and cause light limitation (Wetzel 2001). Studies have shown that seagrasses typically have a high respiratory demand to support a large nonphotosynthetic biomass (e.g.

, roots, rhizomes) ( Fourqurean and Zieman

1991 ). They must regularly oxyg enate their root zone s to compensate for anoxic sediment. If

excessive epiphyton growth causes light limitation o f seagrass es and therefore limit s their photosynthetic capability, seagrass es produce less organic carbon and DO , which in turn result s in les s oxygen be ing transported to the root tissue. Low DO availability at the root zone may

cause seagrass es to rely more on the fermentation pathway to obtain their energy, which may

then stimulate the accumulation of sulfate in sediment. This, in turn, wil l stimulate the respiration of seagrass es and consume more oxygen.

T he excessive growth of epiphyte s may also cause the accumulation of organic materials from

these algae

. In addition, the d ecomposition of these algal materials will consume oxygen in t heTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 18 water. S tudies have also shown that a significant amount of dissolved organic carbon can be released by epiphyton , which stimulate s the growth of bacteria. The r espiration of these

bacteria further decrease s the oxygen concentration in the water colum n. Therefore, controlling nutrient loading from a watershed restrain s excessive epiphyton growth, stimulate s seagrass growth, and improve s the structure of the seagrass community, which in turn improve s DO

concentration s in the lagoon.

However, whether t he control of nutrient loading from the watershed will ensure that DO

concentration s in the lagoon never drop bellow 4 .0 mg/L is uncertain . As discussed previous ly

, seagrass es also respire and consume oxygen. Studies have shown that the growth of seagras s may produce a habitat that slow s down the water flow and increase s the sedimentation of particulate materials from the water column

, trap ping organic materials in the seagrass bed.

This decrease s the DO concentration by decreasing the reaeration rate, a nd also increase s DO consumption in seagrass bed s by stimulating the growth of bacteria using the accumulated organic materials.

The net productivity of seagrass also decrease s as the colonization of seagrass proceeds

. Barron et al. (2004) showed that gross primary production from Cymodocea nodosa increased

from 7 to 49. 3 millimoles of carbon being fixed by seagrass per square meter per day ( mmol C

m - 2 d - 1 ) during the initial stages of colonization and then decreased to 20 mmol C m
- 2 d - 1 when

the biomas s was in excess of 6 moles ( mol C m
- 2 ) . At the same time, c ommunity respiration increased with seagrass colonization, leading to a shift from net autotrophy in the unvegetated sediment community to net heterotrophy after C. nodosa colonization. The incre ase in net heterotrophy with seagrass colonization was reflected in the development of reducing conditions

in the sediment.

The seasonal variation of photosynthetic and nonphotosynthetic tissue may also influence seagrass respiration and, in turn, DO c oncentration s

. Kennish et al. (2007) found that the mean

above

- ground biomass of Zostera marina (eelgrass ) in Barnegat Bay

– Little Egg Harbor peaked during August and September (mean = 13.77 g dry w eight per square meter [ wt m - 2 ] ). In contrast, the mean b elow

- ground biomass was at a maximum from June to July (51.54 g dry wt

m - 2 ). The unsync h ronization of the biomass of photosynthetic and nonphotosynthetic seagrass tissue can also lead to respiration rate s that are higher than oxygen production from photos ynthesis during certain time s of the year.

Based on the above analyses, even after nutrient loading is controlled and the seagrass restoration target is achieved in the lagoon, whether DO concentration will never be lower than the 5.0 mg/L criteria canno t be determined based on the available information. More data need to be collected regarding the relationship between seagrass communities and DO concentration

in the I RL to address the natural DO condition. However, it is reasonable to expect that, when the seagrass full

- restoration target is achieved, the impact of excessive nutrient s from human

sources on DO concentration s in the lagoon should be alleviated

, and DO concentration s should be th ose typically associated with a healthy seagrass community an d provide healthy habitat for fish and other aquatic organisms.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 19 

# Chapter 4: ASSESSMENT OF SOURCES

4.1 Types of Sources

An important part of the TMDL analysis is the identification of pollutant source categories, source subcategories, or individual sou rces of the pollutant of concern in the target watershed and the amount of pollutant loading contributed by each of these sources. Sources are broadly classified as either point sources or nonpoint sources. Historically, the term “ point sources ” has

mean t discharges to surface waters that typically have a continuous flow via a discernable, confined, and discrete conveyance, such as a pipe. Domestic and industrial wastewater treatment facilities (WWTFs) are examples of traditional point sources. In contr ast, the term

“ nonpoint sources ” was used to describe intermittent, rainfall

- driven, diffuse sources of pollution associated with everyday human activities, including runoff from urban land uses, agriculture, silviculture, and mining; discharges from faili ng septic systems; and atmospheric deposition.

However, the 1987 amendments to the Clean Water Act redefined certain nonpoint sources of pollution as point sources subject to regulation under the EPA’s National Pollutant Discharge Elimination System ( NPDE S ) Program. These nonpoint sources included certain urban stormwater discharges, including those from local government master drainage systems, construction sites over five acres, and a wide variety of industries (see Appendix A for background information on the federal and state stormwater programs).

To be consistent with Clean Water Act definitions, the term “point source” is used to describe traditional point sources (such as domestic and industrial wastewater discharges) AND stormwater systems requiri ng an NPDES stormwater permit when allocating pollutant load reductions required by a TMDL ( see Section 6.1 on Expression and Allocation of the TMDL). However, the methodologies used to estimate nonpoint source loads do not distinguish between

NPDES and n on

- NPDES stormwater discharges, and as such, this source assessment section does not make any distinction between the two types of stormwater.



### 4.2 Potential Sources of Pollutants in the IRL and Banana River Lagoon

Watersheds

**4.2.1 Point Sources** 

4.2.1.1 Was tewater Point Sources

Forty

- one NPDES

- permitted facilities were identified in the IRL Basin. Nineteen of these are concrete batch plants that typically receive generic permits, which require that the facilities meet

certain treatment requirement s

, but ha v e no requirement s for routine monitoring. Untreated discharge s from these facilities may be high in turbidity and may also change the pH of receiving waters , b ut they are generally not considered major sources of nutrients.

The remaining facilities , whic h are either industrial or domestic wastewater facilities

, do not contribute significant amount s of nutrient s to the I RL and Banana River Lagoon

, even if they are

NPDES

- permitted facilities:TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 20 (1) T hree facilities

— the **New Smyrna Beach Water Reclamation Fa cility**  (WRF) (FL0172090)

, **Edgewater WWTF**  (FL0021431), and **B revard County Utilities**  **Department (B CUD**  **) /South Central Regional**  **WWTF** (FL0102679)

— are domestic wastewater facilities. Although they are located in the I RL Basin, they

do not discharge into the I RL and Banana River Lagoon s ystem s

. T he New Smyrna Beach W RF and Edgewater W WTF discharge into Mosquito Lagoon

. The BCUD/South Central Regional W WTF discharge s to the St. Johns River.

T

herefore

, these facilities are not considered contributors to the I RL and Banana

River L agoon in this TMDL.

(2) The **Vero Beach Municipal Power Plant** (FL0002984) is located at 100 17 th
Street, Vero Beach (Latitude 27 0 37 ’ 52 ” , Longitude 80 0 22 ’ 33 ” ). The power plant

has 5 power

- generating units. Units #1, #2, and #3 use a tot al of 181 million gallons per day ( MGD ) (Maximum Daily Flow) of water from the Indian River as

once

- through cooling water

, which is discharge d back to the Indian River via

outfalls D

- 011, D

- 012, and D

- 013. As discharge s from these outfalls are recycling I ndian River waters, the discharge s are not considered an addition of

extra nutrient s to the Indian River. Cooling water for the Unit #4 cooling tower is

treated wastewater effluent from the Vero Beach Wastewater Treatment Plant (WWTP). Boiler blowdown is discharged to the WWTP but not to the Indian River. There is no discharge from Unit #5 to the Indian River. Therefore, the Vero Beach Municipal Power Plant is not considered a source of nutrient s in this

TMDL.

(3) The **Cape Canaveral Air Force Station (CCAFS)**  **Regional W WTF**  (FL0102920) is located at Scrub Jay Road, CCAFS (Latitude 28 0 29 ’ 44 ”

, Longitude 80 0 35 ’ 3 ” ). The facility has a 0. 8

- MGD annual average flow capacity. This discharge is completely reused

, and no discharge to a water of the state is

allo wed from th e facility. T he facility was granted a n NPDES permit because it
accepts a small amount of treated hazardous waste

, and federal regulations regarding hazardous waste s require a facility to hold an NPDES permit to accept

hazardous waste s

. The fa cility was therefore not considered a significant

nutrient contributor in this TMDL.

(4) T he **T itusville Osprey W**  **RF** (FL0103268) is located at 1105 Buffalo Road, Titusville. The facility has a 2. 75

- MGD annual average daily flow (AADF) permitted capacity s low

- rate public access

, consisting of on

- site irrigation at the plant and the irrigation of residential lawns, parks, playgrounds, cemeteries, golf courses, highway medians, and other landscape areas. A certain portion of the reclaimed water for golf cour se irrigation is stored in stormwater retention ponds located on each golf course. These ponds intermittently discharge stormwater to adjacent drainage features, which ultimately discharge to the Indian River.

However, as stated in the Department ’s Program Guidance Memo (DOM

- 96

- 01, 1996) regarding reuse activities and NPDES permitting for golf course lakes, as long as a given golf course lake that takes reclaimed water can still hold the first 0.5 inch or 1.0 inch (depending on the area) of runoff from the tributary watershed based on Chapter 62

- 25, F.A.C., and the water quality condition of the reclaimed water meets the requirement of Chapter 62

- 610, F.A.C. (secondary treatment, high

- level disinfection, and 5.0 mg/L TSS) , any discharges from the l ake to waters of the state likely will consist primarily ofTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 21 stormwater

. Therefore, the discharge from the facility is implicitly considered in

this TMDL as part of the nonpoint source loadings through stormwater. No WLA is assigned to the facility.

In addition to the discharge to golf course lakes, the facility also has an existing

2.75

- MGD maximum monthly flow permitted wet

- weather backup discharge to

the Blue Heron Water Reclamation Facility, which has an existing 4.0

- MGD annual average discharge flow . The reclaimed water from the Titusville W RF

will be blended with the reclaimed water from the Blue Heron W RF and discharged through a constructed wetland system to Addison Canal and then to

the St. Johns River. Based on th is information , the Titus ville W RF i s not considered a major nutrient contributor to the I RL system.

Table 4.1 lists all the NPDES

- permitted facilities that are considered significant contributors of

nutrient s into the IRL and Banana River Lagoon

, and the lagoon segments that the y discharge

into . Figure 4.1 shows the location of these facilities. Table s 4.2 and 4.3 show long

- term average annual loads for TN and TP , respectively, from these facilities during the six

- year period from 2000 through 2005

.

The 6

- year long

- term annual TN loadings from these wastewater facilities ranged from none to more than 13,000 lbs/yr. The facilities that discharged the highest amount of TN to the IRL

include the Cocoa Beach W RF (FL0021105), which discharged about 13,652 lbs of TN per year, and th e Vero Beach WWTF (FL0021661), which discharged about 12,993 lbs of TN per year. Other significant TN dischargers include the Melbourne R everse Osmosis (R O ) WWTF (FL0043443) and Cocoa W RF Facility (FL0021521), which discharged about 6,558 and 6148 lbs/yr of TN, respectively, from 2000 to 2005.

The 6

- year long

- term annual TP loadings from these facilities follow a similar pattern to that of TN. TP loadings ranged from none to about 2,622 lbs/yr. The two facilities that discharged the highest amount of TP are, again, the Cocoa Beach W RF , which discharged about 2,622 lbs of TP per year, and the Vero Beach W WTF , which discharged about 1,064 lbs of TP per year. Other significant TP dischargers include the Cocoa W RF and Vero Beach R O WTF (FL0042544), which di scharged about 575 and 536 lbs/yr of TP, respectively, from 2001 to

2005.

Long

- term annual average nutrient loads from several facilities could not be calculated, even though these facilities are listed in Table 4.2 . This was either because a given faci lity did not have a TN and TP monitoring requirement between 2000 and 2005, or because the facility did not discharge a significant quantity of TN and/or TP into the IRL during the period of calculation. For example, the Cape Canaveral Power Plant (FL0001 472), located in the city of Cocoa, has several effluent points into the IRL, including two once

- through cooling water (OTCW) outfalls and one auxiliary equipment cooling water (AECW ) outfall

, that use the water from the IRL. The IRL water is used primari ly as cooling water. No significant amount of TN and TP is added to the water, which is discharged back to the IRL. The cooling water is therefore not considered a major source of TN and TP to the lagoon.

The facility also has three stormwater outfall s from an equipment area, a fuel oil storage tank area, and a nonequipment area. These stormwater discharges were routed to a runoff disposalTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 22 Figure 4.1. NPDES

- P ermitted F acilities L ocated in the I RL and Banana

Riv er Lagoon WatershedsTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 23 Table 4.1. Point Source Facilities that Discharge into the IRL and Banana River

Lagoon

NPDES

Permit

Number Facility Name Facility Type City, County Impacted Segment

FL0021521 Cocoa / J. Sellers WWTP Domestic WWTP Cocoa, Brevard IR6

- 7

FL0001473 Florida Power & Light ( FPL ) Cape Canaveral

Power Plant Power Plant with RO Cocoa, Brevard IR6

- 7

FL0042005 Morton Salt Industrial Wastewater Cape Canaveral,

Brevard BR1

- 2

FL0020541 City of Cape Canaveral Domestic WWTP Cape Canaveral,

Brevard BR 3

- 5

FL0021105 City of Cocoa Beach Domestic WWTP Cocoa Beach, Brevard BR3

- 5

FL0000680 Reliant Energy Indian

River Power Plant Titusville, Brevard IR6

- 7

FL0021571 City of Rockledge WWTP Domestic WWTP Rockledge, Brevard IR8

FL0043443 Melbourne RO WTF RO M elbourne, Brevard IR9

- 11

FL0040622 Brevard Co unty Utilities Department (BCUD)/

South Beaches Domestic WWTP Melbourne, Brevard IR12

FL0041122 Melbourne / Grant St.

WWTP Domestic WWTP Melbourne, Brevard IR12

FL0042293 Barefoot Bay WWTP Domestic WWTP Barefoo t Bay, Brevard IR14

- 15

FL0021661 City of Vero Beach

WWTP Domestic WWTP Vero Beach, Indian

River IR16

- 20

FL0042544 Vero Beach RO WTF RO Vero Beach,

Indian River IR16

- 20

FL0166511 Indian River County Utilities Department (IRCUD)/

Hobart RO WTF RO Vero Be ach,

Indian River IR16

- 20

FL0041637 IRCUD/ West Regional Domestic WWTP Vero Beach,

Indian River IR16

- 20

FL0037940 I RCUD/ South RO WTF RO Vero Beach,

Indian River IR16

- 20TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 24 Table 4.2. Long

- Term A nnual A verage TN L oadings from NPDES

- P ermitted F acilitie s ( 2000

– 05)

NPDES

Permit

Number Facility Name Long

- T erm
Annual M ean
TN (mg/L) Long

- T erm A nnual

M ean D ischarge ( million gallon s /yr) Long

- T erm
A nnual M ean TN

L oading (lb s /yr)

FL0021521 Cocoa / J. Sellers WWTP 5.78 128 6

, 148

FL0001473 FPL Cape Canaveral Pow er Plant N/A N/A N/A

FL0042005 Morton Salt 2.74 21 492

FL0020541 City of Cape Canaveral 1.05 169 1475

FL0021105 City of Cocoa Beach 6.27 238 13

, 652

FL0000680 Reliant Energy Indian River N/A 8 N/A

FL0021571 City of Rockledge WWTP N/A 0 N/A

FL0043443 M elbourne R O WTF 2.4 3 32 3 6

, 558

FL0040622 B CUD/ South Beaches 8.09 6.1 415

FL0041122 Melbourne / Grant St. WWTP 10.78 0.45 44

FL0042293 Barefoot Bay WWTP 2.29 6.0 123

FL0021661 City of Vero Beach WWTP 11.85 131 12

, 993

FL0042544 Vero Beach R O WTF 2.39 1 2 1 2

, 419

FL0166511 I RCUD/ Hobart RO WTF 1.90 134 2

, 123

FL0041637 IRCUD / We s t Regional 0. 73 235 1

, 422

FL0037940 I RCUD/ South RO WTF 1.51 300 3

, 795

N/A

– D ischarge data are not available or the load cannot be calculated for the reasons described in this secti on.

Table 4.3

. L ong

- Term A nnual A verage TP L oadings from NPDES

- P ermitted F acilities
( 2000

– 05)

NPDES

Permit

Number Facility Name Long

- T erm
Annual M ean

T P (mg/L) Long

- T erm A nnual

M ean D ischarge ( million gallon s /yr) Long

- T erm
A nnual M ean T P

L oading (lb s /yr )

FL0021521 Cocoa / J. Sellers WWTP 0.54 128 575

FL0001473 FPL Cape Canaveral Power Plant N/A N/A N/A

FL0042005 Morton Salt 0.57 21 103

FL0020541 City of Cape Canaveral 0.11 169 161

FL0021105 City of Cocoa Beach 1.32 238 2

, 622

FL0000680 Reliant Energy I ndian River 0.20 * 8 * 12 *

FL0021571 City of Rockledge WWTP N/A 0 N/A

FL0043443 Melbourne R O WTF 0.04 323 96

FL0040622 BCUD / South Beaches 1.50 6.1 77

FL0041122 Melbourne, Grant St. WWTP 0.45 0.45 2

FL0042293 Barefoot Bay WWTP 0.35 6.0 19

FL0021661 City of Vero Beach WWTP 1.06 131 1

, 064

FL0042544 Vero Beach R O WTF 0.34 121 536

FL0166511 I RCUD/ Hobart RO WTF 0.04 142 45

FL0041637 IRCUD/ We s t Regional 0.04 235 84

FL0037940 I RCUD/ South RO WTF 0.04 300 103

N/A

– D ischarge data are not available or the lo ad cannot be calculated for the reasons described in this section

.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 25 area. T he disposal area only overflows under heavy rainfall and was therefore not considered a major source of TN to the lagoon. Before the facility renewed its permit in 2005, it used t reated ground water for the boiler and blowdown . The reject from the treated ground water was discharged directly to the IRL

. As nutrient s were not considered a major issue for the reject discharg e at the time , no TN and TP discharge limits were applied to the discharge.

When the permit was renewed in 2005, the facility started to use treated wastewater as source water for the boiler and blowdown. TN and TP discharge loading limits were applied to the reject discharge of the treated wastewater (annual average daily loads of 7 lb s /day for TN and

0.4 lb s /day for TP)

. However, as the TN and TP loading limits established for the reject discharge are annual loading limits, and the facility did not start to collect TN an d TP samples until 2006, no 5

- year lo ng

- term annual average TN and TP loadings could be calculated for the facility for the period from 2001 to 2005.

The vast majority of the discharge from the Reliant Energy Indian River Power Plant (maximum daily average of 820 MGD) was OTCW from the IRL

. No extra TN and TP loadings were added to the lagoon through the cooling water. The only other surface water discharges from the plant are boiler blowdown (maximum monthly average 0.297 MGD) and nonindustrial stormwater (roof runoff), which are also dire cted to the discharge canal (no discharge limit). As the facility adds trisodium phosphate and disodium phosphate into the boiler blowdown to control pH, the permit requires the facility to monitor the TP concentrations of the boiler blowdown discharge on a monthly basis. Table 4. 4 shows the TP concentrations in this discharge from January 2000 through October 2007.

Because the facility started to use a new method to control pH in February 2003, the TP concentration of the boiler blowdown discharge was dramatically decreased compared with the TP concentration before February 2003. To represent the existing condition of the facility, a

five

- year long

- term average TP loading from the facility was calculated based on data from 2003 through 2007. No signi ficant amount of TN was added into the discharge from the Reliant Energy p lant.

The Rockledge W WTF (FL0021571), located in the c ity of Rockledge, Brevard County, has a permitted average daily flow (ADF) of 4.5 MGD discharge d to the I RL . However, this dis charge is limited to a period not to exceed 7 days during the Mechanical Integrity Testing of the facility’s underground injection well, which is conducted once every 5 years. In other times, the 4.5

- MGD ADF is directed to a permitted underground injectio n well system. T he facility also has a 1.6

- MGD AADF reuse system, which irrigates a reuse service area around the facility. As

necessary, wet

- weather flows from the reuse system are discharged to the underground injection well. F rom 2001 through 2005, t here was no discharge from the facility.

All the above facilities discharged a total of about 48,695 lbs of TN and 4,716 lbs of TP into the IRL and Banana River Lagoon per year.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 26 Table 4. 4. TP C oncentration of the B oiler B lowdown D ischarge for the

Reliant Energy Indian River Power Plant

Date Flow (MGD) TP (mg/L) Date Flow (MGD) TP (mg/L)

1/31/2000 0.018 1.88 9/30/2003 0.058 0.311

2/29/2000 0.052 1.49 10/31/2003 0.023 0.161

3/31/2000 0.011 1.8 11/30/2003 0.01 0.098

4/30/2000 0.048 2.1 12/31/2003 0.0 17 0.067

5/31/2000 0.051 3 1/31/2004 0.03 0.04

6/30/2000 0.083 26.1 2/29/2004 0.021 0.03

7/31/2000 0.132 7.74 3/31/2004 0.03 0.04

8/31/2000 0.131 2.5 4/30/2004 0.029 0.045

9/30/2000 0.165 1 5/31/2004 0.03 0.04

10/31/2000 0.049 1.2 6/30/2004 0.029 0.0 5

11/30/2000 0.041 0.9 7/31/2004 0.037 0.09

12/31/2000 0.048 2 8/31/2004 0.038 0.05

1/31/2001 0.033 1.3 9/30/2004 0.049 0.075

2/28/2001 0.036 1.1 10/31/2004 0.039 0.071

3/31/2001 0.039 1.1 11/30/2004 0.008 0.09

4/30/2001 0.044 1.6 12/31/2004 0.02 0.0 5

5/31/2001 0.07 1.5 1/31/2005 0.014 0.085

6/30/2001 0.091 1.3 2/28/2005 0.016 0.04

7/31/2001 0.107 2.2 3/31/2005 0.02 0.028

8/31/2001 0.09 0.32 4/30/2005 0.02 0.05

9/30/2001 0.088 0.67 5/31/2005 0.024 0.07

10/31/2001 0.067 N/A 6/30/2005 0.004 0.063

11/30/2001 0.041 N/A 7/31/2005 0.016 0.05

12/31/2001 0.025 N/A 8/31/2005 0.019 0.045

1/31/2002 0.047 3.1 9/30/2005 0.068 0.085

2/28/2002 0.038 3 10/31/2005 0.001 0.05

3/31/2002 0.032 1.81 11/30/2005 0.0003 0.04

4/30/2002 0.047 1.56 12/31/2005 0.006 0 .06

5/31/2002 0.031 2.66 2/28/2006 0.004 0.07

6/30/2002 0.031 2.62 3/31/2006 0.007 0.06

7/31/2002 0.014 1.9 4/30/2006 0.012 0.08

8/31/2002 0.059 1.11 5/31/2006 0.005 0.09

9/30/2002 0.028 1.11 6/30/2006 0.005 0.1

10/31/2002 0.029 1.61 7/31/2006 0.008 0.15

11/30/2002 0.023 1.29 8/31/2006 0.046 0.06

12/31/2002 0.022 3.66 9/30/2006 0.007 0.09

1/31/2003 0.027 2.77 10/31/2006 0.005 0.11

2/28/2003 0.018 0.84 11/30/2006 0.008 0.09

3/31/2003 0.051 0.89 12/31/2006 0.008 0.09

4/30/2003 0.037 0.49 1/31/2007 0.001 0.05

5/31/2003 0.027 0.053 2/28/2007 0.001 0.05TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 27 Date Flow (MGD) TP (mg/L) Date Flow (MGD) TP (mg/L)

6/30/2003 0.032 0.082 4/30/2007 0.001 0.05

7/31/2003 0.054 0.067 9/30/2007 0.021 0.05

8/31/2003 0.077 0.088 10/31/2007 0.025 0.07

N/A

– N o monitoring data are available.

4.2.1.2 Municipal Separ ate Storm Sewer System Permittees

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

use s 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. In October 2000, the EPA authorized the Department to implement the NPDES S tormwater P rogram in all areas of Florida

, except for Indian t ribal lands. The Department’s authority to administer the NPDES P rogram is set forth in Section 403.0885,

F .S . The three major components of the NPDES stormwater regulations are as follows :

(1) **Municipal Separate Storm Sewer System (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 t o reduce the discharge of pollutants from the MS4 to the maximum extent practicable.

(2) **Stormwater Associated with Industrial Activities,** which is regulated primarily by a multisector general permit that covers various types of industrial facilities.

Re gulated industrial facilities must obtain NPDES stormwater permit coverage and implement appropriate pollution prevention techniques to reduce

contamination of stormwater.

(2) **Construction A**  **ctivity G**  **eneric P**  **ermits** for projects that ultimately disturb one

or more acres of land and that require the implementation of stormwater pollution prevention plans to provide erosion and sediment control during

construction.

In addition to the NPDES stormwater construction permitting regulations, Florida was the first state in the country to require the treatment of stormwater for all new developments with the adoption of the s tate Stormwater Rule in late 1981. The Stormwater Rule is a technology

- based program that relies on the implementation of best management practi ces ( BMPs ) designed to achieve a specific level of treatment (i.e., performance standards)

, as set forth in Chapter 62

- 40, F.A.C. In 1994, state legislation created the Environmental Resource Permitting P rogram to consolidate stormwater quantity, stormwat er quality, and wetlands protection into a single permit. Currently , the majority of E nvironmental R esource P ermits are issued by the state’s five water management districts, although the Department continues to do the permitting for specified projects.

The NPDES S tormwater P rogram 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, the EPA implemented Pha se 1 of the MS4 P ermitting P rogram on a countywide basis, which brings in all cities, Chapter 298TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 28 urban water control districts, and the Florida D epartment of Transportation (FD OT ) throughout

the 15 counties meeting the population criteria. Phase II of th e NPDES Program was expanded in 2003 and requires stormwater permits for construction sites between 1 and 5 acres, and for local governments with as few as 10,000 people.

Although MS4 discharges are technically referred to as “point sources” for the purpo se of regulation, they are still diffuse sources of pollution that cannot be easily collected and treated by a central treatment facility. All Phase 1 MS4 permits issued in Florida include a reopener clause allowing permit revisions for implementing TMDLs once they are formally adopted by

rule. Florida’s Phase II MS4 Generic Permit has a “self

- implementing” requirement once TMDLs are adopted that requires the MS4 permittee to update its stormwater management

program ( as needed ) to meet its TMDL allocation s.

Table 4. 5 lists the counties, cities, and townships with MS4 permits influenced by TMDLs in the

IRL and Banana River Lagoon watersheds

.

Table 4.5. MS4 Permittees Affected by TMDLs in the IRL and Banana

River Lagoon Watersheds

MS4 Permit

Phase Permit N ame Permit Number County

II FDOT District 4 FLR04E083 None

II FDOT District 5 FLR04E024 None

II Brevard County FLR04E052 Brevard

II City of Titusville FLR04E079 Brevard

II City of Cape Canaveral FLR04E003 Brevard

II City of Cocoa FLR04E032 Brevard

I I City of Cocoa Beach FLR04E062 Brevard

II Town of Rockledge FLR04E047 Brevard

II City of Satellite Beach FLR04E072 Brevard

II Patrick Air Force Base FLR04E074 Brevard

II City of Indian Harbor Beach FLR04E026 Brevard

II Town of Indialantic FLR04E030 B revard

II City of Melbourne FLR04E027 Brevard

II Town of Melbourne Beach FLR04E041 Brevard

II City of West Melbourne FLR04E028 Brevard

II City of Palm Bay FLR04E077 Brevard

II Town of Malabar FLR04E050 Brevard

II Indian River County FLR04E068 Indian River

II City of Sebastian FLR04E124 Indian River

II Town of Indian River Shores FLR04E009 Indian River

II City of Vero Beach FLR04E010 Indian River

II St. Lucie County FLR04E029 St. Lucie

II City of Fort Pierce FLR04E065 St. LucieTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 29 

### 4.2.2 Nonpoint **Sources**

Other than the TN and TP loadings from NPDES

- permitted point sources, the majority of the nutrient loadings are primarily generated from nonpoint sources in the watershed . Major nonpoint sources may include, but are not limited to, loadings throug h surface runoff, ground water, and atmospheric deposition directly onto the surface of the lagoon system. Based on stepwise regression analyses conducted by the SJRWMD, the atmospheric sources of nutrients

d o not significantly affect the relationship bet ween watershed nutrient loadings and seagrass depth distributions at **α** = 0.15 (Steward and Green 2006). Therefore, the atmospheric nutrient loadings were not included in the loading versus depth

- limit regression analyses. However, as

the se loadings are p art of the total nutrient budgets that these lagoons receive, the y were calculated in this TMDL report and added to both the existing total nutrient loadings and TMDLs.

Ground water input from the Floridan aquifer does not represent a significant portio n of the total water budget for the I RL system (Martin et al. 2004 ). Depending on the season, i nput from the surficial aquifer to the lagoon could be important. Nutrient contributions from the surficial aquifer were implicitly included in the SJRWMD’s mo del simulation s as part of the budget for watershed flow and nutrient loadings.

As discussed in Chapter 3, the SJRWMD used both the PLSM and HSPF M odel to simulate TN and TP loadings from the watershed. This TMDL is based on the watershed loadings simula ted by these models. The PLSM, a GIS

- based stormwater runoff model, was originally developed as a tool to assist the SJRWMD in watershed planning. The SJRWMD assessed its reliability in estimating annual nutrient loads to determine PLRGs for the IRL (Ste ward and Green 2006).

Th e PLSM generates pollutant loads from multiple

, spatially distributed inputs such as land use, soil types, hydrologic boundaries, rainfall, runoff coefficients, event mean concentrations (EMCs), and BMPs. In assessing the model’ s reliability in predicting nutrient pollutant loads, the

PLSM was calibrated for runoff volume, TN, TP, and TSS to flow and loading estimates based

on measured data in four IRL drainage basins : Crane Creek, C

- 1 Canal of Turkey Creek, South Prong of Sebas tian River, and Briar Creek (Green and Steward 2003). The SJRWMD study

concluded that PLSM loads predicted reasonably well the measured flow, and the TN, TP, and TSS loadings derived from measured concentrations and flow. Figure 4.2 shows the combined

ru noff volume and TN, TP, and TSS loadings for the four creeks , as simulated by PLSM

, versus measured runoff volume and TN, TP, and TSS loadings in the se creeks

.

For comparison purpose s

, the SJRWMD also developed an HSPF Model to simulate the TN

and TP load ings from the I RL

. HSPF (Bick n ell et al. 2004 )

, developed and maintained by Aqua

Terra and the EPA, is a comprehensive package that can be used to develop a combined watershed and receiving water model. It can simulat e various species of nitrogen and pho sphorus, chla , BOD, coliform bacteria, metals, and DO concentrations in receiving waters. The model has three major modules , as follows, that simulate pollutant loadings from the

watershed and in

- water transport of the pollutants and their effects on chla and DO

concentrations :

**•** The PERLND Module performs a detailed analysis of surface and subsurface flow for pervious land areas based on the Stanford Watershed Model. Water quality calculations for sediment in pervious land runoff can include sediment d etachment during rainfall events and reattachment during dry periods

, with the potential for washoff during runoff events. For other water quality constituents, runoff water quality can be determined using buildup

- washoff algorithms, “potency factor” (e.g

.,TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 30 factors relating constituent washoff to sediment washoff), or a combination of

both.

**•** The IMPLND M odule analyzes surface processes only and uses buildup

- washoff algorithms to determine runoff quality.

**•** The RCHRES Module is used to simulate flow routin g and water quality in receiving waters, which are assumed to be one

- dimensional. Receiving water constituents can interact with suspended and bed sediments through soil

- water partitioning.

The HSPF M odel can incorporate “special actions” that utilize use r

- specified algorithms to account for occurrences such as opening/closing of water control structures to maintain seasonal water stages or other processes beyond the normal scope of the model code.

Based on SJRWMD studies, both loading models provide comp arable annual loading estimates for the IRL and Banana River Lagoon systems (Green and Steward 2003). The major purpose of watershed TN and TP simulations is to find the relationship between pollutant loadi ngs and seagrass depth limit. There were d iffere nces between the PLSM and HSPF results : one or the other provided a stronger regression outcome for a given sublagoon or pollutant; therefore the stronger of the two sets of regressions, based on correlation and significance statistics (R 2 and p values), was selected to determin e the final loading.

Figure 4.2. PLSM Estimated Versus Measured Loads for Four Creeks in

the I RL Watershed (Green and Steward 2003)TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 31 In the PLRG analysis, the PLSM loads generally produced better regression statistics than the

HSPF loads

. However, the HSPF

- estimated loads for TP produced a better set of regression

statistics for the North I RL and thus dictated the annual TP loading for that sublagoon ( Steward

and Green 2006

, 2007)

.

4.2.2.1 Land Uses

No matter what model was used for watershed loading simulation, land use patterns in the I RL and Banana River Lagoon watersheds are among the most important factors influencing pollutant loadings. L and use pattern s influence the imperviousness of the watershed and

determine the a mount of runoff that can be produced in a given watershed area. T he se pattern s also determine the concentrations of pollutant s in the runoff produced in a given area

and therefore determine the amount of a given pollutant that can be produced per acre of drainage basin. Knowing the land use distribution in the watershed is therefore very important in simulating the pollutant watershed loading.

Table 4. 6 s ummarize s the land use patterns in the watersheds that drain into each lagoon segment in all the th ree sublagoon areas : North IRL, Central Central IRL, and Banana River Lagoon. The land use summary was conducted based on Level 1 land use in the Florida Land

U se, Cover, and Forms Classification System (FLUCCS 1984). This analysis used the

SJRWMD’s 200 0 land use GIS coverage. It should be noted that the surface areas of lagoons are not considered part of the watershed s and therefore are not included in the water land use areas in Table 4. 6

. Table 4. 7 shows the percent distribution of each land use in each

watershed

.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 32 Table 4. 6

. Land U se Distribution (in acres) in the I RL and Banana River Lagoon Watersheds

Sub l agoon Lagoon Segment Urban

and

Built

Up Low

Density

Residentia l Medium

Density

Residentia l High

Density

Residentia l Agriculture Rangeland Upland

Forest Water Wetland Barren

Land Transportation

, Communication,

and Utilities Sub t otal

North IRL IR1

- 3 247 1

, 894 570 137 7

, 129 6

, 120 6

, 533 494 27

, 776 545 564 52

, 009

IR4 351 264 66 384 274 68 199 5 334 36 246 2

, 227

IR5 2

, 312 150 479 1

, 115 662 6

, 621 2

, 024 349 18

, 428 465 749 33

, 353

IR6

- 7 1

, 297 1

, 679 1

, 862 982 3

, 407 1

, 666 1

, 240 830 7

, 928 90 911 21

, 892

IR8 550 505 694 238 88 178 185 50 132 15 109 2

, 744

IR9

- 11 4

, 028 1

, 106 4

, 667 3

, 593 175 1

, 178 1

, 624 848 1

, 477 84 1

, 131 19

, 910

Sub t otal 8

, 784 5

, 5 97 8

, 338 6

, 449 11

, 735 15

, 831 11

, 805 2

, 576 56

, 074 1

, 234 3

, 710 132

, 135

Central IRL IR12 14

, 466 3

, 899 23

, 071 2

, 730 8

, 461 6

, 799 7

, 102 1

, 641 4

, 626 932 2

, 394 76

, 121

IR13A 37 248 126 78 5 549 565 19 142 2 48 1

, 820

IR13B 561 1

, 941 820 113 808 3

, 455 4

, 832 530 3

, 413 69 298 16

, 840

IR14 5

, 046 5

, 261 5

, 508 1

, 383 41

, 810 18

, 161 19

, 289 2

, 357 16

, 024 1

, 032 1

, 294 117

, 156

IR15 559 128 419 192 606 151 542 122 728 44 43 3

, 533

IR16

- 20 6

, 540 4

, 383 9

, 155 3

, 160 24

, 439 3

, 963 6

, 084 1

, 393 3

, 833 682 2

, 140 65

, 773

IR21 145 84 527 241 28 106 378 65 737 8 37 2

, 358

Sub t otal 27

, 355 15

, 944 39

, 626 7

, 897 76

, 157 33

, 184 38

, 793 6

, 127 29

, 503 2

, 768 6

, 255 283

, 609

Banana

River Lagoon BR1

- 2 3

, 880 139 0.0 0.1 105 9

, 148 9

, 281 2

, 036 7

, 846 188 473 33

, 095

BR3

- 5 2

, 633 102 1

, 182 1

, 433 8 356 278 217 1

, 047 38 300 7

, 593

BR6 720 110 802 1

, 244 108 156 186 1

, 153 1

, 602 39 194 6

, 314

BR7 592 88 2

, 433 601 11 262 73 243 13 34 71 4

, 420

Sub t otal 7

, 825 439 4

, 416 3

, 278 231 9

, 921 9

, 818 3

, 649 10

, 507 299 1

, 038 51

, 423

Total 43

, 965 21

, 980 52

, 380 17

, 624 88

, 12 4 58

, 936 60

, 416 12

, 352 96

, 085 4

, 301 11

, 003 467

, 167TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 33 Table 4. 7

. Percent Land U se Distribution in the I RL and Banana River Lagoon Watersheds

Sub l agoon Lagoon Segment Urban

and

Built

Up Low

Density

Residential Medium

Density

Residential High

Density

Reside ntial Agriculture Rangeland Upland

Forest Water Wetland Barren

Land Transportation, Communication,

and Utilities Sub t otal

North IRL IR1

- 3 0.5% 3.6% 1.1% 0.3% 13.7% 11.8% 12.6% 0.9% 53.4% 1.0% 1.1% 100.0%

IR4 15.7% 11.9% 3.0% 17.3% 12.3% 3.0% 8.9% 0.2% 1 5.0% 1.6% 11.0% 100.0%

IR5 6.9% 0.4% 1.4% 3.3% 2.0% 19.9% 6.1% 1.0% 55.3% 1.4% 2.2% 100.0%

IR6

- 7 5.9% 7.7% 8.5% 4.5% 15.6% 7.6% 5.7% 3.8% 36.2% 0.4% 4.2% 100.0%

IR8 20.0% 18.4% 25.3% 8.7% 3.2% 6.5% 6.7% 1.8% 4.8% 0.6% 4.0% 100.0%

IR9

- 11 20.2% 5.6% 23.4% 18.0% 0.9% 5.9% 8.2% 4.3% 7.4% 0.4% 5.7% 100.0%

Sub t otal 6.6% 4.2% 6.3% 4.9% 8.9% 12.0% 8.9% 1.9% 42.4% 0.9% 2.8% 100.0%

Central IRL IR12 19.0% 5.1% 30.3% 3.6% 11.1% 8.9% 9.3% 2.2% 6.1% 1.2% 3.1% 100.0%

IR13A 2.1% 13.6% 6.9% 4.3% 0.3% 30.2% 31.0 % 1.1% 7.8% 0.1% 2.6% 100.0%

IR13B 3.3% 11.5% 4.9% 0.7% 4.8% 20.5% 28.7% 3.1% 20.3% 0.4% 1.8% 100.0%

IR14 4.3% 4.5% 4.7% 1.2% 35.7% 15.5% 16.5% 2.0% 13.7% 0.9% 1.1% 100.0%

IR15 15.8% 3.6% 11.9% 5.4% 17.1% 4.3% 15.3% 3.4% 20.6% 1.2% 1.2% 100.0%

IR16

- 20 9.9% 6.7% 13.9% 4.8% 37.2% 6.0% 9.3% 2.1% 5.8% 1.0% 3.3% 100.0%

IR21 6.2% 3.5% 22.4% 10.2% 1.2% 4.5% 16.1% 2.8% 31.3% 0.3% 1.6% 100.0%

Sub t otal 9.6% 5.6% 14.0% 2.8% 26.9% 11.7% 13.7% 2.2% 10.4% 1.0% 2.2% 100.0%

Banana

R iver Lagoon BR1

- 2 12.4% 0.4% 0.0% 0.0% 0.3% 29.2% 29.6% 0.9% 25.0% 0.6% 1.5% 100.0%

BR3

- 5 34.9% 1.4% 15.7% 19.0% 0.1% 4.7% 3.7% 2.1% 13.9% 0.5% 4.0% 100.0%

BR6 12.1% 1.9% 13.4% 20.9% 1.8% 2.6% 3.1% 13.5% 26.8% 0.6% 3.3% 100.0%

BR7 13.4% 2.0% 55.0% 13.6% 0.2% 5.9% 1.7% 5.5% 0.3% 0.8% 1.6% 100.0%

Sub t otal 15.9% 0.9% 9.0% 6.7% 0.5% 20.1% 19.9% 3.0% 21.3% 0.6% 2.1% 100.0%

Total 9.5% 4.7% 11.3% 3.8% 19.0% 12.7% 13.0% 2.2% 20.7% 0.9% 2.4% 100.0%TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 34 Based on Table 4. 6 , the IRL and Banana River Lagoon watersheds cover a total of abou t 467,167 acres (not including lagoon surface areas). There are about 132,135 acres, 283,609 acres, and 51,423 acres in the watersheds of the North IRL, Central IRL, and Banana River Lagoon, respectively. At the lagoonwide scale, urban areas

— including lo w

- , medium

- , and high

- density residential; transportation, communication, and utilities; and other urban and built

up land uses

— comprise about 146,953 acres, or about 31 percent of the total drainage area.

These areas account for 25, 34, and 35 percent of the drainage areas in the North IRL, Central IRL, and Banana River Lagoon, respectively. In addition to these human land use areas, agricultural lands are important in the Central IRL, accounting for about 27 percent of its watershed area. Agricultural lands account for about 9 percent and 0.4 percent of the total drainage areas in the North IRL and Banana River Lagoon watersheds, respectively.

The dominant natural land use in the watersheds of these sublagoons is wetlands, which total about 96,085 acre s and account for about 21 percent of the total drainage area. U pland forest and rangeland each account for about 13 percent of the total drainage areas to these lagoons. Percent drainage basin dominated by wetlands is highest in the North IRL watershed, at about 42 percent, followed by the Banana River Lagoon watershed, at about 21 percent. The highest percent drainage areas dominated by upland forests, about 20 percent, are observed in the Banana River Lagoon watershed. This is followed by 14 percent of upland forest areas in the Central IRL watershed and 9 percent in the North IRL watershed.

Percent drainage basin occupied by rangelands accounts for about 12, 12, and 20 percent, in the North IRL, Central IRL, and Banana River Lagoon watersheds, res pectively. Water surface areas other than the lagoon surface areas are relatively insignificant, occupying only 2 to 3 percent of the drainage areas in all three watersheds.

T he highest percent human land use dominance appears in the Central IRL watersh ed,

account ing for 61 percent of the drainage area. Human land uses occupy 34 to 35 percent of the North IRL and Banana River Lagoon watersheds, respectively. Figure s 4.3

, 4.4

, and 4.5 show the spatial distribution of Level 1 land uses in the IRL and Ban ana River Lagoon

watersheds.

4.2.2.2 Nonpoint Source TN and TP Loadings from the Watersheds

Drain ing into the I RL and Banana River Lagoon

Existing nonpoint source TN and TP loadings from most watersheds that drain into the I RL and Banana River Lagoon wer e simulated using the PLSM and were mostly based on 2000 land use and 30

- year mean annual rainfall. Level 3 land use classification was used in conducting the

actual PLSM simulation. TP loadings into North I RL segments were simulated using the HSPF

Model because there was a better correlation between watershed HSPF TP loading simulates and seagrass depth limit s than between PLSM TP loading simulates and seagrass depth limit s

. As the HSPF Model was used to simulate continuous watershed loading on a daily basis, daily

rainfall data for the 9 year s between 1995 and 2003 were used in place of long

- term annual average rainfall

.

Other than land use information, other model inputs required by the PLSM to simulate watershed TN and TP loadings include drainage basin boundary, hydrologic soil groups, annual rainfall, land use and hydrologic soil specific runoff coefficient s , and the EMCs of TN and TP

associated with different land uses. Figure 4. 6 shows the drainage basin delineation providedTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 35 Figure 4. 3

. Major Land Uses in the North I RL WatershedTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 36 Figure 4. 4

. Major Land Uses in the Central I RL WatershedTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 37 Figure 4.5. Major Land Uses in the Banana River Lagoon WatershedTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 38 Figure 4.6. I RL and Banana River Lagoon Watershed Delineation and Locations of

National Weather Service StationsTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 39 by the SJRWMD. Detailed runoff coefficients for different land use

– hydrologic soil combinations

and th e EMCs of TN and TP associated with different land use categories used in the PLSM

simulation can be found in Appendix A of the EPA’s seagrass nutrient and DO TMDL report ( 2007).

The 30

- year long

- term annual rainfall from five National Weather Service rai n gages in the watershed (Daytona Beach International Airport, Titusville, Melbourne International Airport, Vero Beach Airport, and Fort Pierce) were used in simulating TN and TP watershed loadings for the existing condition. Figure 4.6 shows the location s of these weather stations.

Table 4. 8 lists the long

- term annual average rainfall and the annual rainfall for each individual year from 2000 through 2005 at each of the five weather stations. The actual rainfall amounts used for simulating the TN and TP loadings from the drainage area discharge into a specific lagoon segment were calculated as the average annual rainfall of the nearby weather stations using the Thiessen Polygon method. As sh own in the table , t he annual rainfall from these

stations fro m 2000 through 2005 ranged from 34.8 to 69.9 inches. The average 30

- year long

term annual average from 1975 to 2005 was about 53.1 inches. The period used to develop the nonpoint load and derive the WLA for the NPDES facilities includes a reasonable rang e of dry and wet years.

Table 4. 8 . Annual Rainfall (inches) ( 2000

– 05 ) and 30

- Year Long

- T erm Annual Average Rainfall (1975

– 2005) at Five N ational Weather

Service Stations Used in the Development of This TMDL (EPA

2007)

Year Daytona Beach

Int ernational

Ai rport Titusville Melbourne

Int ernational Airport Vero Beach

A irport Fort Pierce

2000 49.6 56.85 61.66 58.73 63.11

2001 40.47 34.76 43.25 46.14 39.42

2002 53.31 59.32 65.92 50.6 60.62

2003 69.91 58.57 56.94 54.88 44.19

2004 47.87 47.72 40.54 46.07 53.2 6

2005 65.51 61.65 61.6 61.22 58.06

30

- Y ear Mean 51.18 53.84 50.73 55.79 54.04

Note: Rainfall totals were calculated from April to the following March to correspond with the modeling and seagrass mapping year used by the SJRWMD

.

Table 4. 9 lists the n o npoint source loadings of TN and TP from the IRL and Banana River Lagoon watershed s estimated using the above information and models

. Per

- acre pollutant loading represents the intensity at which a given pollutant is discharged from a given land use

area. Table 4. 10 provides per

- acre nonpoint source TN and TP loadings in the watershed s discharging to different I RL and Banana River Lagoon segments.

Total nonpoint source TN and TP loadings are 2,661,593 and 457,495 lbs/yr, respectively,

which translate int o about 5.7 lbs/ac/yr of TN and 1.0 lbs/ac/yr of TP. S ublagoonwide per

- acre TN loadings are 4.4, 6.3, and 5.6 lbs/ac/yr for the North IRL, Central IRL, and Banana RiverTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 4 0 Table 4. 9

. Nonpoint Source Loadings of TN and TP from the I RL and

Banana River Lagoo n Watershed s

Sub l agoon Lagoon Segment TN (lb s /yr) TP (lb s /yr)

North IRL IR1

- 3 134

, 968 13

, 901

IR4 20

, 743 4

, 435

IR5 125

, 855 20

, 377

IR6

- 7 115

, 901 18

, 6 18

IR8 24

, 288 4

, 418

IR9

- 11 154

, 658 31

, 758

Sub t otal 576

, 413 93

, 507

Central IRL IR12 508

, 473 81

, 6 61

IR13 62

, 789 7

, 743

IR14

- 15 728

, 453 121

, 192

IR16

- 20 484

, 025 96

, 052

IR21 12

, 323 2

, 359

Sub t otal 1

, 796

, 063 309

, 007

Banana R iver Lagoon BR1

- 2 127

, 782 20

, 660

BR3

- 5 73

, 704 17

, 044

BR6 46

, 213 9

, 724

BR7 41

, 418 7

, 553

Sub t otal 289,117 54,981

Tota l Loading 2,661,593 457

, 495

Lagoon, respectively, and lagoonwide per

- acre TP loadings are 0.7, 1.1, and 1.0 lbs/ac/yr, respectively.

In addition, of the total TN loadings (including point sources and nonpoint sources) into the 3 sublagoons, point sourc e TN loadings account for 2.2, 1.3, and 5.1 percent in the North IRL, Central IRL, and Banana River Lagoon, respectively. Point source TP loadings account for about 0.7, 0.6, and 5.0 percent of total TP loadings (including point sources and nonpoint

sourc es) into the North IRL, Central IRL, and Banana River Lagoon, respectively. Nonpoint sources are the dominant source of TN and TP loadings in the IRL and Banana River Lagoon.

4.2.2.3 TN and TP Loadings from Atmospheric Deposition Directly onto the

Surfa ce of the IRL and Banana River Lagoon

As discussed in Section 4.2.2 , although no significant correlation was observed between seagrass depth limit and nutrient loads through atmospheric deposition directly onto the lagoon surface, atmospheric deposition do es contribute to the nutrient loadings to the IRL and Banana River Lagoon. Therefore, nutrient loadings through atmospheric deposition are calculated in this TMDL report and added to the existing loadings and TMDLs.

Table 4.11 lists the surface areas and watershed areas of all the lagoon segments (Steward et al. 2005) . Of the total areas of these lagoon segments, from 8 to 7 3 percent are lagoon surfaceTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 41 Table 4.10. Per

- Acre Nonpoint Source Loadings of TN and TP from the I RL

and Banana River Lagoon Water shed s

Sub l agoons Lagoon Segment TN (lb s /yr) TP (lb s /yr) Basin Area (acres) Per

- Acre

TN Load (lb s /ac/yr) Per

- Acre

TP Load (lb s /ac/yr)

North IRL IR1

- 3 134,968 13,901 52

, 009 2.6 0.3

IR4 20,743 4,435 2

, 227 9.3 2.0

IR5 125,855 20,377 33

, 353 3.8 0.6

IR6

- 7 115,901 18,618 21

, 892 5.3 0.9

IR8 24

, 288 4,418 2

, 744 8.9 1.6

IR9

- 11 154,658 31,758 19

, 910 7.8 1.6

Sub t otal 576,413 93,507 132

, 135 4.4 0.7

Central IRL IR12 508,473 81,661 76

, 121 6.7 1.1

IR13 62,789 7,743 18

, 661 3.4 0.4

IR14

- 15 728,453 121,192 12 0

, 698 6.0 1.0

IR16

- 20 484,025 96,052 65

, 773 7.4 1.5

IR21 12,323 2,359 2

, 358 5.2 1.0

Sub t otal 1,796,063 309,007 283

, 609 6.3 1.1

Banana

R iver Lagoon BR1

- 2 127,782 20,660 33

, 095 3.9 0.6

BR3

- 5 73,704 17,044 7

, 593 9.7 2.2

BR6 46,213 9,724 6

, 314 7.3 1 .5

BR7 41,418 7,553 4

, 420 9.4 1.7

Sub t otal 288,625 54,878 51

, 423 5.6 1.1

Total 2,661,593 457,495 467

, 167 5.7 1.0

areas. Overall, the surface areas of the I RL and Banana River Lagoon account for about 25 percent of the lagoon and watershed areas.

The SJRWMD provided the b ulk TN and TP atmospheric deposition rates used in this TMDL report ( J.W. Steward, M. Lasi, and W.C. Green, personal communication). These rates were

estimated based on data collected from an atmospheric deposition site (IRL 141) located at

Sebastian Inlet between 2001 through 2006. Site IRL 141 belongs to the Clear Air Status and Trends Network (CASTNET), which has been sponsored by the EPA since 2006. Between
2001 and 2006, the SJRWMD maintained the site (Rogers 2007).

Typic ally, CASTNET sites only collect dry deposition data. However, at Site IRL 141, the SJRWMD maintains a wet deposition collector, which collects the wet deposition data using a protocol similar to that used by the National Atmospheric Deposition Program (N ADP). The bulk deposition rates for TN and TP used in this TMDL were the sum of the CASTNET dry deposition

rate and the NADP

- style wet deposition rate. Because the CASTNET sites typically do not measure ammonia gas and organic nitrogen, the dry depositio n data were adjusted for ammonia and organic nitrogen with a multiplication factor of 1.25, based on published literature (Poor et al. 2001, Russel et al. 2003, Barna et al. 2008). Areal wet deposition rate is related to

rainfall.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 42 Table 4. 11

. Surface Areas of the I RL and Banana River Lagoon Segments

Sub l agoon Lagoon Segment Lagoon

Surface (Acres) Segment Drainage

Area (Acres) Total Segment

Area (Acres) % Lagoon Surface

Area in Total Segment Area

North IRL IR1

- 3 21,763 52,009 73,772 29 %

IR4 2,367 2 ,227 4,594 5 1 %

IR5 16,556 33,353 49,909 32 %

IR6

- 7 16,042 21,892 37,934 42 %

IR8 3,803 2,744 6,547 58%

IR9

- 11 12,209 19,910 32, 1 1 9 38%

Central IRL IR12 8,566 76,121 84,687 10%

IR13 3,645 18,660 22,305 16%

IR14

- 15 13,865 120,689 134, 554 10%

IR1 6

- 20 6,010 65,773 71, 783 8 %

IR21 2,545 2,358 4, 903 52%

Banana River Lagoon BR1

- 2 18,755 33,095 51,850 36%

BR3

- 5 21,338 7,593 28.931 7 3 %

BR6 3,872 6,314 10,186 40 %

BR7 1,905 4,420 6,325 31 %

Total 153,241 467,158 620,399 25%

Because the SJRWMD used long

- term average annual rainfall for the period from 1975 to 2005 to simulate long

- term average annual TN and TP loadings from the watershed, the average annual areal wet deposition rates estimated based on 2001 through 2006 data were adjusted

with the long

- term average annual rainfall (1975 to 2005). The long

- term average annual rainfall values applied to the North I RL , Central IRL , and Banana River Lagoon are 53.2, 53.3,

and 50.6 in ches per year , respectively ( J.W. Steward, M. Lasi, and W.C. Green , personal communication)

.

Total atmospheric TN and TP loadings depositing directly onto the lagoon surface were calculated by multiplying the areal atmospheric deposition rates by the surface area of each lagoon segment. Table 4. 1 2 lists the total TN and TP atmospheric loads to the I RL and Banana River Lagoon segments. Table s 4. 1 3a and 4. 1 3b show the total nonpoint source TN and TP loadings from both watershed runoff and atmospheric direct deposition.

The total nonpoint source TN annual load to the I RL and Banana River Lagoon is about
3,280,163 lbs/yr. Total TN annual load to each lagoon segment range s from 22,738 to 785,187 lbs/yr ( Table 4.1 3a ). The overall percent TN annual load resulting from direct atmospheric deposition to the surface of the l agoon system is about 19 percent . Depending on the percent lagoon surface area in the total area and the land use patterns of each lagoon segment, the percent TN load from direct atmospheric deposition range s from 5 percent (IR16

- 20) to 53
percent (BR3

- 5) . TN loadings through direct atmospheric deposition represent a significant portion of the TN loadings received by the I RL and Banana River Lagoon.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 43 Table 4. 12

. Atmospheric TN and TP Loadings Depositing Directly onto the

Surface of the I RL and Banana Riv er Lagoon Segments

Sub l agoon Lagoon Segment Lagoon

Surface ( acres ) TN Areal Deposition

Rate (lb s /ac/yr) TP Areal Deposition

Rate (lb s /ac/yr) Annual TN Atmospheric

Load (lb s /yr) Annual TP Atmospheric

Load (lb s /yr)

North IRL IR1

- 3 21,763 4.09 0.093 88,898 2 ,013

IR4 2.367 4.09 0.093 9,670 219

IR5 16,556 4.09 0.093 67,630 1,532

IR6

- 7 16,042 4.09 0.093 65,531 1,484

IR8 3,803 4.09 0.093 15,535 352

IR9

- 11 12,209 4.09 0.093 49,875 1,129

Central IRL IR12 8,566 4.09 0.093 35,051 794

IR13 3,645 4.09 0.09 3 14,915 338

IR14

- 15 13,865 4.09 0.093 56,734 1,285

IR16

- 20 6,010 4.09 0.093 24,591 557

IR21 2,545 4.09 0.093 10,415 236

Banana R iver Lagoon BR1

- 2 18,755 3.92 0.093 73,486 1,649

BR3

- 5 21,338 3.92 0.088 83,604 1,876

BR6 3,872 3.92 0.088 15,172 34 0

BR7 1,905 3.92 0.088 7,465 168

Total 153,241 618,570 13,972

Table 4. 13a

. Total Nonpoint Source TN Loads (lb s /yr) to the I RL and

Banana River Lagoon Segments

Sub l agoon Lagoon Segment Atmospheric Deposition Load Drainage

Basin Load Total Nonpoint

S ource Load % Atmospheric Loads in

the Total Nonpoint

Source Load

North IRL IR1

- 3 88,898 134,968 223,866 40 %

IR4 9,670 20,743 30,413 32 %

IR5 67,630 125,855 193,485 35 %

IR6

- 7 65,531 115,901 181,432 36 %

IR8 15,535 24,288 39,823 39 %

IR9

- 11 49,875 15 4,658 204,533 24 %

Central IRL IR12 35,051 508,473 543,524 6 %

IR13 14,915 62,789 77,704 19 %

IR14

- 15 56,734 728,453 785,187 7 %

IR16

- 20 24,591 484,025 508,616 5 %

IR21 10,415 12,323 22,738 46 %

Banana R iver Lagoon BR1

- 2 73,486 127,782 201,268 37 %

BR 3

- 5 83,604 73,704 157,308 53 %

BR6 15,172 46,213 61,385 25 %

BR7 7,465 41,418 48,883 15 %

Total 618,570 2,661,593 3,280,163 19 %TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 44 Table 4. 13b

. Total Nonpoint Source TP Loads (lb s /yr) to the I RL and

Banana River Lagoon Segments

Sub l agoon Lagoon Segment At mospheric Deposition Load Drainage

Basin Load Total Nonpoint

Source Load % Atmospheric

Loads in the Total Nonpoint Source

Load

North IRL IR1

- 3 2,013 13,901 15,914 13 %

IR4 219 4,435 4,654 5 %

IR5 1,532 20,377 21,909 7 %

IR6

- 7 1,484 18,618 20,102 7 %

I R8 352 4,418 4,770 7 %

IR9

- 11 1,129 31,758 32,887 3 %

Central IRL IR12 794 81,661 82,455 1 %

IR13 338 7,743 8,081 4 %

IR14

- 15 1,285 121,192 122,477 1 %

IR16

- 20 557 96,052 96,609 1 %

IR21 236 2,359 2,595 9 %

Banana R iver Lagoon BR1

- 2 1,649 20,660 22,30 9 7 %

BR3

- 5 1,876 17,044 18,920 10 %

BR6 340 9,724 10,064 3 %

BR7 168 7,553 7,721 2 %

Total 13,972 457,495 471,467 3 %

The total nonpoint source TP annual load to the I RL and Banana River Lagoon is about 471,467 lbs/yr. T he t otal T P annual load to ea ch lagoon segment range s from 2,595 to 122,477 lbs/yr ( Table 4. 1 3b ). The overall percent TP annual load from direct atmospheric deposition to the surface of the lagoon system is about 3 percent

, which is lower than the percent TN contributed by atmospheri c direct deposition (19 percent)

.

Depending on the percent lagoon surface area in the total area and the land use patterns of each lagoon segment, the percent T P load from direct atmospheric deposition range s from 1
percent ( IR12, IR14

- 15, and IR16

- 20) to 13 percent ( IR1

- 3 ). Compared with the total nonpoint source TP loading into the I RL and Banana River Lagoon, T P loading through direct atmospheric deposition represent a relatively small portion of the total load

.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 45 

# Chapter 5: DETERMINATION OF ASSIMI LATIVE

CAPACITY

5.1 Overall Approach

As discussed in Chapter 3, once the target seagrass depth limit was established, the loading targets for TN and TP, or the TN and TP assimilative capacity of the I RL and Banana River Lagoon

, were established through t he following steps :

(1) Nonpoint source TN and TP loadings were estimated using the PLSM (TP for the

North IRL was based on the HSPF Model ) for 1943, 1996, 1999, and 2001

based on land use distribution and rainfall corresponding to these years. Total

lo adings from each segment for each year were calculated as the sum of point source and nonpoint source loadings. There were no 1942

– 43 point source data, and so only runoff load estimates were used for that year. The SJRWMD believed that any point source loading from 1942 to 1943 should be relatively negligible and would have no significant bearing on the regression results.

(2) Total TN and TP loadings were converted to per

- acre loading for each lagoon segment and these loadings were log

- transformed.

(3) Log

- transformed TN and TP loadings were regressed against the percent deviation of seagrass depth limits in1943, 1996, 1999, and 2001 ; and target log TN and TP loadings were established at

- 10 percent deviation ( shallower ) of the

seagrass depth limit fro m the full

- restoration target

.

(4) The target log TN and TP loadings were then back

- transformed to a target per

acre TN and TP loading using the nonparametric method described by Duan (1983 ).

Table 3.2 lists the a rea l loading for TN and TP for the three sublagoon s

. Based on the per

- acre TN and TP loading targets and the acreages of the drainage areas discharging to different lagoon segments, total drainage area TN and TP loading targets (lb s /yr) were developed for different segments

. It should be noted that the TN and TP loadings from point sources were included in the total drainage area loadings when conducting the seagrass depth limit versus loading regression analysis . Therefore, the target allowable loads derived for the drainage

basin based on the regression also include point source contributions. I t is important to note

that the TMDLs presented in this report focus on reducing the TN and TP loadings from the drainage basin s

, and that loadings from atmospheric deposition are considered part of th e allowable loads that will not be changed from the existing condition. The final allowable loads (TMDL) are calculated as the sum of the allowable drainage basin loads (including point sour ce loads , surface runoff load, and ground water loads ), and the d irect atmospheric loads.

Table 5.1 lists t he final allowable loads

. It also includes the existing total TN and TP loading s for these segments, which include the drainage basin loadings, point source loadings, loadingsTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 46 from direct atmospheric deposi tion and loadings from ground water , and the percent reductions of TN and TP loadings required to achieve the target loadings.

The total TN and TP loadings discharged into impaired WBIDs were also calculated, based on the corresponding spatial relation ship between the SJRWMD’s IRL and Banana River Lagoon segmentation and the Department’s WBID delineation. Table 5.2 lists the impaired WBIDs and their corresponding IRL and Banana River Lagoon segments. Because segment boundaries do not always match up w ith WBID boundaries, the aggregation of WBIDs and segments was conducted to capture comparable watersheds. Table 5.2 also shows the existing TN and TP loadings and target TN and TP loadings into the impaired WBIDs, and the required TN and TP

load reductio ns to achieve the target loads. Figure 5

. 1 shows the spatial relationship between WBID boundaries and the SJRWMD’s segment boundaries.

Table 5.1. TN and TP Existing and Target Loadings and Load Reduction s Required to Achieve the Target Loadings

TN TP

Existing Loading (lb s /yr) Target Loading (lb s /yr) Required

Reduction (lb s /yr; %) Existing Loading (lb s /yr) Target Loading (lb s /yr) Required

Reduction (lb s /yr; %)

North IRL

North IRL

(total) 886,257 687,044 199,213 ( 22 %) 100,919 56,550 44,369 ( 44 %)

IR1

- 3 223,866 177,220 46,646 ( 21 %) 15,914 9,320 6,594 ( 41 %)

IR4 30,413 23,244 7,169 ( 24 %) 4,654 2,550 2,104 ( 45 %)

IR5 193,485 149,988 43,497 ( 22 %) 21,909 12,243 9,666 ( 44 %)

IR6

- 7 187,580 147,524 40,056 ( 21 %) 20,689 11,845 8,844 ( 43 %)

IR8 39,823 31,429 8,394 ( 21 %) 4,770 2,674 2,096 ( 44 %)

IR9

- 11 211,091 157,640 53,451 ( 25 %) 32,983 17,918 15,065 ( 46 %)

Central I RL

Central IRL (total) 1,961,103 962,988 998,115 ( 51 %) 314,148 165,193 148,955 ( 47 %)

IR12 543,983 261,412 282,571 ( 52 %) 82534 43,170 39,364 ( 48 %)

IR 13 77,704 42,811 34,893 ( 45 %) 8,081 4,348 3,733 ( 46 %)

IR14

- 15 785,310 380,491 404,819 ( 52 %) 122,496 64,076 58,420 ( 48 %)

IR16

- 20 531,368 262,384 268,984 ( 51 %) 98,442 52,141 46,301 ( 47 %)

IR21 22,738 15,890 6,848 ( 30 %) 2,595 1,458 1,137 ( 44 %)

Banana River Lagoon

Banana R iver Lagoon (total) 484,462 291,755 192,707 ( 40 %) 61,900 23,253 38,647 ( 62 %)

BR1

- 2 201,760 116,314 85,446 ( 42 %) 22,412 7,825 14,587 ( 65 %)

BR3

- 5 172,435 123,434 49,001 ( 28 %) 21,703 9,755 11,948 ( 55 %)

BR6 61,385 30,661 30,724 ( 50 %) 10,06 4 3,247 6,817 ( 68 %)

BR7 48,883 21,347 27,536 ( 56 %) 7,721 2,426 5,295 ( 69 %)TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 47 Table 5.2. TN and TP Existing and Target Loadings to Impaired WBIDs and

Load Reduction s Required T o Achieve the Target Loadings

WBID Segment TN TP

Existing Loading (lb s /yr) Target Loading (lb s /yr) Required

Reduction (lb s /yr; %) Existing Loading (lb s /yr) Target Loading (lb s /yr) Required

Reduction (lb s /yr; %)

North I RL

North IRL ( total ) 886,257 687,044 199,213 ( 22 % ) 100,919 56,550 44, 369 ( 44 % )

2963F IR1

- 3 223,866 177,220 46, 646 ( 21 %) 15,914 9,320 6,594 ( 41 %)

2963E IR4+IR5 223,898 173,232 50,666 ( 23 %) 26,563 14,793 11,770 ( 44 %)

2963D IR6

- 7 187,580 147,524 40,056 ( 21 %) 20,689 11,845 8, 844 ( 43 %)

2963B+2963C IR8+IR9

- 11 250,913 189,068 61,845 ( 25 %) 37,753 20,592 17,161 ( 45 %)

C entral I RL

Central IRL ( total ) 1,961,103 962,988 998,115 ( 51 % ) 314,148 165,193 148, 955 ( 47 % )

5003D+2963A IR12+IR13+

IR14

- 15 1,406,998 684,715 722,283 ( 51 %) 213,111 111,594 101,517 ( 48 %)

5003B+5003 C IR16

- 20+

IR21 554,105 278,273 275,832 ( 50 %) 101,037 53 ,599 47,438 ( 47 %)

Banana River Lagoon

Banana R iver Lagoon ( total ) 484,462 291,755 192, 707 ( 40 % ) 61,900 23,253 38, 647 ( 62 % )

3057C BR1

- 2 201,760 116,314 85

, 446 ( 42 %) 22,412 7,825 14, 587 ( 65 %)

3057A+3057B BR3

- 5+BR 7 221,317 144,780 76,537 ( 35 %) 29,424 12, 181 17,243 ( 59 %)

3044A BR6 61,385 30,661 30,724 ( 50 %) 10,064 3,247 6,817 ( 68 %)TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 48 Figure 5

. 1

. Spatial Relationship B etween the Department ’s WBID

Boundaries and the SJRWMD’s Segment BoundariesTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 49 

# Chapter 6: DETERMIN ATION OF THE TMDL

6.1 Expression and Allocation of the TMDL

The objective of a TMDL is to provide a basis for allocating acceptable loads among all of the known pollutant sources in a watershed so that appropriate control measures can be implemented and water quality standards achieved. A TMDL is expressed as the sum of all point source loads ( w aste l oad allocations , or WLAs), nonpoint source loads ( load allocations , or LAs), and an appropriate margin of safety (MOS), which takes into account any uncertai nty concerning the relationship between effluent limitations and water quality:

TMDL = **∑** WLAs + **∑** LAs + MOS

As discussed earlier, the WLA is broken out into separate subcategories for wastewater discharges and stormwater discharges regulated under the NPDES Program:

TMDL **≅ ∑**  WLAs wastewater + **∑** WLAs NPDES Stormwater + **∑** LAs + MOS

It should be noted that the various components of the revised TMDL equation may not sum up

to the value of the TMDL because ( 1 ) the WLA for NPDES stormwater is typically ba sed on the percent reduction needed for nonpoint sources and is also accounted for within the LA, and ( 2 ) TMDL components can be expressed in different terms (for example, the WLA for stormwater is typically expressed as a percent reduction, and the WLA fo r wastewater is typically expressed as mass per day).

WLAs for stormwater discharges are typically expressed as percent reduction because it is very difficult to quantify the loads from MS4s (given the numerous discharge points) and to distinguish the loa ds from MS4s from other nonpoint sources (given the nature of stormwater transport). The permitting of stormwater discharges also differs from the permitting of most wastewater point sources. Because stormwater discharges cannot be centrally collected,

m onitored, and treated, they are not subject to the same types of effluent limitations as wastewater facilities, and instead are required to meet a performance standard of providing treatment to the “maximum extent practical” through the implementation of B MPs.

This approach is consistent with federal regulations (40 CFR § 130.2[I]), which state that TMDLs can be expressed in terms of mass per time (e.g., pounds per day), toxicity, or other appropriate

measure . TMDLs for the main stem segments of the IRL a nd Banana River Lagoon are expressed in terms of lbs/yr

, lbs/ day

, and percent reduction of TN and TP, and represent the long

- term average TN and TP loadings that these I RL and Banana River Lagoon segments can assimilate and maintain balanced aquatic flora and fauna ( Table s 6.1 a and 6. 1b ). It should be

noted that the expression of the TMDL on a mass

- per

- day basis is for information al purposes only . The implementation of these TMDL s should be carried out using an annual time scale.

Based on a recent EPA me morandum (2006), daily loads of TN and TP from point and nonpoint sources were also calculated ( Tables 6.2 a and 6.2 b ) . These daily loads were calculated by dividing the annual loads by 365 days/yr and are only provided in this report for informational

pur poses. The implementation of the TMDLs covered in this TMDL report should be carried out using an annual time scale.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 50 Table 6. 1a

. TN TMDL Components for Nutrient

- Impaired WBIDs of the IRL

and Banana River Lagoon Main Stem

WBID Parameter TMDL ( lb s /yr ) WLA NPDES

waste water (lb s /yr) WLA NPDES

Stormwater * LA (lb s /yr) MOS

2963F TN 177,220 N/A 35% 177,220 Implicit

2963E TN 173,232 N/A 35% 173,232 Implicit

2963D TN 147,524 8

, 111 36% 139,413 Implicit

2963B+2963C TN 189,068 9

, 200 36% 179,868 Implicit

5003D+296 3A TN 684,715 831 56% 683,884 Implicit

5003B+5003C TN 278,273 25

, 391 56% 252,882 Implicit

3057C TN 116,314 1

, 214 67% 115,100 Implicit

3057A+3057B TN 144,780 6

, 173 59% 138,607 Implicit

3044A TN 30,661 N/A 66% 30,661 Implicit

N/A

– N ot applicable.

* The r equired percent reduction for WLA NPDES Stormwater was considered the same as the required percent reduction for nonpoint source loading ( Table 6.3 ). Refer to the discussion in Section 6.3.2 for details

.

Table 6.1 b. TP TMDL Components for Nutrient

- I mpa ired WBIDs of the IRL

and Banana River Lagoon Main S tem

WBID Parameter TMDL (lb s /yr) WLA NPDES

wastewater (lb s /yr) WLA NPDES

Stormwater LA (lb s /yr) MOS

2963F TP 9,320 N/A 47% 9,320 Implicit

2963E TP 14,793 N/A 47% 14,793 Implicit

2963D TP 11,845 1

, 609 53% 10,236 Implicit

2963B+2963C TP 20,592 225 48% 20,367 Implicit

5003D+2963A TP 111,594 122 48% 111,472 Implicit

5003B+5003C TP 53,599 1

, 949 48% 51,650 Implicit

3057C TP 7,825 302 72% 7,523 Implicit

3057A+3057B TP 12,181 1221 64% 10,960 Implicit

3044A TP 3,247 N/A 70% 3,247 Implicit

N/A

– N ot applicable.

* The r equired percent reduction for WLA NPDES Stormwater was considered the same as the required percent reduction for nonpoint source loading ( Table 6.3 ). Refer to the discussion in Section 6.3.2 for details.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 51 Table 6.2 a. TN TMDL Daily Loads for Nutrient

- Impaired WBIDs of the IRL

and Banana River Lagoon Main Stem

WBID Parameter TMDL (lb s / day ) WLA NPDES

wastewater (lb s / day ) WLA NPDES

Stormwater LA (lb s / day ) MOS

2963F TN 486 N/A 35% 486 Implicit

2963 E TN 475 N/A 35% 475 Implicit

2963D TN 404 22** 36% 382 Implicit

2963B+2963C TN 518 25** 36% 493 Implicit

5003D+2963A TN 1,876 2** 56% 1,874 Implicit

5003B+5003C TN 762 70** 56% 692 Implicit

3057C TN 319 3** 67% 316 Implicit

3057A+3057B TN 397 17** 5 9% 380 Implicit

3044A TN 84 N/A 66% 84 Implicit

N/A

– N ot applicable. ** Daily WLAs were calculated by dividing the annual loads by 365 days. In reality, daily WLAs for different facilities have different applicable time scales. The daily WLAs at diff erent time scales are not directly addable. The daily WLAs in this table are only for

information al purpose s

. Section 6.3.1 contains a d etailed WLA for each facility and the applicable time scale.

Table 6.2 b. TP TMDL Daily Loads for Nutrient

- Impaired W BIDs of the IRL

and Banana River Lagoon Main Stem

WBID Parameter TMDL (lb s / day ) WLA NPDES

wastewater (lb s /day) WLA NPDES

Stormwater LA (lb s /day) MOS

2963F TP 26 N/A 47% 26 Implicit

2963E TP 41 N/A 47% 41 Implicit

2963D TP 32 4.4** 53% 28 Implicit

2963B+ 2963C TP 56 0.6** 48% 56 Implicit

5003D+2963A TP 306 0.3** 48% 305 Implicit

5003B+5003C TP 147 5.3** 48% 142 Implicit

3057C TP 21 0.8** 72% 21 Implicit

3057A+3057B TP 33 3.3** 64% 30 Implicit

3044A TP 9 N/A 70% 9 Implicit

N/A in this table means not applicable. ** Daily WLAs were calculated by dividing the annual loads by 365 days. In reality, daily WLAs for different facilities have di fferent applicable time scales. Daily WLAs at different time scales are not directly addable. The daily WLAs in t his table are only for

information al purpose s

. Section 6.3.1 contains a detailed WLA for each facility and the applicable time scale.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 52 

### 6.2 Load Allocation

As discussed in Chapter 4 , the vast majority of TN and TP loadings in the I RL and Banana River

L ag oon watersheds come from nonpoint sources. Point source discharge s typically account for

less than 5 percent of the total watershed load. Major sources of nonpoint nutrient loadings include watershed runoff, ground water input, and direct atmospheric dep osition onto the lagoon

surface.

Based on Table s 6. 1 a and 6. 1 b , the total allowable LA s for TN for the impaired WBIDs range

from 30,661 lb s /yr for WBID 3044A ( Newfound Harbor)

, to 683,884 lb s /yr for WBID s 5003D and 2963A (South Indian River and Indian Riv er above Sebastian Inlet, respectively). For TP, the LAs range from 3,247 lb s /yr for WBID 3044A (Newfound Harbor)

, to about 111,472 lb s /yr for

WBID s 5003D and 2963A (South Indian River and Indian River above Sebastian Inlet, respectively).

Assuming tha t atmospheric direct deposition will remain the same for the existing and target

condition s , t o achieve the allowable LAs listed in Table s 6. 1 a and 6. 1 b , TN and TP loading s from watershed nonpoint sources need to be reduced as follows:

(1) The required percent reduction s for WBIDs located in the North I RL

— WBID 2963F (Indian River above Melbourne Brewer), WBID 2963E (Indian River above NASA Causeway), WBID 2963D (Indian River above 520 Causeway),

WBID 2963B (Indian River above Melbourne Causeway), and WBI D 2963C (Indian River above Melbourne Causeway )

— range from 35 to 3 6 percent for TN

and 47 to 53 percent for TP loadings.

(2) For the WBIDs located in the Central I RL

— which include several South I RL segments ( WBIDs 5003B, 5003D, and 5003E) and WBID 2963 A (Indian River

above Sebastian Inlet )

— the required percent load reductions are 56 percent for

TN and about 48 percent for TP.

(3) For the WBIDs located in the Banana River Lagoon

— WBID 3057C (Banan a River above Barge Canal), WBID 3057A (Banana River be low M athers), WBID 3057B (Banana River above 520 Causeway), and WBID 3044A (Newfound

Harbor )

— the required percent reductions range from 56 to 67 percent for TN

, and 64 to 72 percent for TP.

As the focus of this TMDL is to reduce the nutrient loadings fr om the lagoon watershed

, and the seagrass depth

- limit and nutrient load relationship was derived only based on the watershed loading, the percent load reductions needed to achieve the restoration target ( Table s 6. 1 a and

6. 1 b ) were calculated only based on the nonpoint source loading from the watershed

. Table

6.3 a lists the existing and total allowable nonpoint source TN and TP loadings from the

watershed without including the loadings from direct atmospheric deposition i n the calculation

. The table also s hows the percent reductions that need to be applied to the nonpoint drainage basin load to achieve the restoration target.

On the other hand, t he needed percent reductions can also be calculated based on the total nonpoint source loadings, which include loading from atmospheric direct deposition. Table 6. 3bTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 53 lists the existing nonpoint source TN and TP loadings, the nonpoint source TMDLs for TN and TP, and the percent reduction required to achieve the TMDL targets when atmospheric direct deposition onto the lagoon surface is considered. As Table 6. 3b shows, calculating the needed percent reduction by including direct atmospheric deposition result s in lower needed percent reductions. In this TMDL, the percent reduction focuses on the watershed load reduc tion, which requires a higher percent nutrient reduction. This approach adds to the MOS

.

Table 6.3 a

. Required Percent Reductions o f TN and TP Loads , by WBID, To

Achieve Restoration Targets (Excluding Atmospheric
Deposition)

WBID TN TP

Existing Nonpoin t

Load (lb s /yr) LA (lb s /yr) %

Reduction Existing Nonpoint Load (lb s /yr) LA (lb s /yr) %

Reduction

2963F 134

, 968 88,322 35% 13

, 901 7,307 47%

2963E 146

, 598 95,932 35% 24

, 812 13,042 47%

2963D 115

, 901 73,882 36% 18

, 618 8,752 53%

2963B+2963C 178

, 946 114,459 3 6% 36

, 176 18,886 48%

5003D+2963A 1299

, 715 577,183 56% 210

, 596 109,055 48%

5003B+5003 C 496

, 348 217,877 56% 98

, 411 50,857 48%

3057C 127

, 782 41,614 67% 20

, 660 5,874 72%

3057A+3057B 115

, 122 47,539 59% 24

, 597 8,916 64%

3044A 46

, 213 15,489 66% 9

, 724 2,907 7 0%

Table 6. 3b

. Required Percent Reductions of TN and TP Loads , by WBID, To

Achieve Nonpoint Source Loading Targets (Including
Atmospheric Deposition)

WBID TN TP

Existing Nonpoint

Load (lb s /yr) LA (lb s /yr) %

Reduction Existing Nonpoint Load (lb s /yr) LA (lb s /yr) %

Reduction

2963F 223,866 177,220 21% 15,914 9,320 41%

2963E 223,898 173,232 23% 26,563 14,793 44%

2963D 181,432 139,413 23% 20,102 10,236 49%

2963B+2963C 244,355 179,868 26% 37,657 20,367 46%

5003D+2963A 1,406,416 683,884 51% 213,013 111,47 2 48%

5003B+5003 C 531,353 252,882 52% 99,204 51,650 48%

3057C 201,268 115,100 43% 22,309 7,523 66%

3057A+3057B 206,190 138,607 33% 26,641 10,960 59%

3044A 61,385 30,661 50% 10,064 3,247 68%TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 54 

### 6.3 Wasteload Allocation

**6.3.1 N PDES**  **Wastewater Discharg es** 

As discussed in Chapter 4, 16 NPDES

- permitted wastewater facilities a re considered significant

TN and TP contributors to the IRL and Banana River Lagoon watersheds ( Table 4.1 )

. W LAs for each facility were developed considering their current permit limi ts, the quality and frequency of their actual discharge, and the assimilative capacity of the receiving waters. For each NPDES facility, monthly discharge volume and TN and TP concentration data were retrieved directly

from the Discharge Monitoring Report s submitted to the Department

. Annual TN and TP loads

were calculated for 2001 through 2005. The arithmetic mean and the 95 th percentile of these

annual loads were also calculated.

Tables 6. 4 a and 6. 4 b provide TN and TP values , respectively, for these facilities

. These average annual loads and the 95 th percentile of the annual loads were compared with permitted loads and discharge concentrations for each facility. Those facilities that already achieve advanced wastewater treatment (AWT) nutrient conc entrations (3 mg/L for TN and 1 mg/L for TP) and/or discharge infrequently were allocated annual TN and TP loads equivalent to the 95 th
percentile of their discharged nutrient load s for 2001 to 2005. For facilities that do not m e et the

AWT concentration r equirements and discharge a relatively large quantity of nutrient s into the lagoon system, the long

- term average annual TN and/or TP loads are assigned as the facilities’

WLA.

Based on a recent EPA memorandum ( 2006 )

, daily loads of TN and TP from point sources should be calculated. In this TMDL report, daily WLAs for facilities that have whole

- year daily discharge are calculated as annual loads divided by 365 days. The daily WLAs for facilities that are only allowed to discharge over limited period s le ss than 365 days are calculated as annual loads divided by the allowable numbers of discharge days. These daily loads are only applicable to those allowable discharge days. It should be noted that the daily loads presented in this report are for informat ion al purpose s only . The implementation of these TMDLs and

WLAs will be based on an annual time scale. T he WLAs are assigned to the identified facilities

as follow s :

(1) **Cocoa /** 

**J. Seller**  **s W**  **RF (FL0021521):**  The facility has a 4. 5

- MGD average daily flow p ermitted discharge to the I RL at Segment IR6

- 7. The permit allows a surface discharge from the facility for no more than 91 days (or the equivalent of 2,184 hours) per year

. The rest of the time, the treated wastewater is directed to

a 4. 5

- MGD AADF permi tted capacity slow

- rate public access system consisting

of on

- site irrigation and decorative ponds, irrigation of residential lawns, parks, playgrounds, cemeteries, golf driving ranges, highway medians, and other landscape areas within the Reuse Service Ar ea

. The anticipated reuse demand

from these areas is about 5. 98

- MGD AADF.

Through the years, the facility has made great efforts to reduce its nutrient loadings into the I RL

. Other than the land application of treated wastewater, it

also has tak en steps to decrease discharge nutrient concentrations. TheTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 55 Table 6.4a. Permitted Annual TN Limits, Discharges, and WLAs for Facilities and TMDLs for Each Lagoon Segment

Lagoon Segment NPDES Facility 2000

– 05 Flow Weighted

Concentration TN (mg/L) 1 Annu al Average Load

2001

– 05 TN

(lbs/yr) 2 95 th Percentile

Annual Load TN (lbs/yr) 3 Permit

Concentration TN (mg/L) 4 Permit

Flow Equiv. (MGD) 5 Permit

Annual

Load TN (lbs/yr) 6 TMDL TN (lbs/yr) 7 WLA TN (lbs/yr) 8

North IRL

IRL1

- 3 N/A 177,220

IR4 N/A 23,244

IR5 N/A 149,988

IR6

- 7 FL0021521 Cocoa /

J. Seller s 5.78 5,556 8,932 12 1.125 41,007

147,524 5,556

IR6

- 7 FL0001473 Cape

Canaveral PP N/A N/A N/A N/A N/A 2,555 2,555

IR6

- 7 FL0000680 Reliant Energy Indian River N/A N/A N/A N/A 0. 297 N/A N/A

IR8 FL0021571 Rockledge N/A 0 0 12 0.062 2,253 31,429 30

IR9

- 11 FL0043443

Melbourne RO 2.43 6,585 9,170 3 1.250 11,422 157,640 9,170

Central IRL

IR12 FL0040622

BCUD / South

Beaches 8.09 62 173 12 0.123 4,506

261,412 173

IR12 FL00411 22

Melbourne / Grant

Street 10.78 53 182 20 0.068 2,503 182

IR13 N/A 42,811

IR14

- 15 FL0042293 Barefoot Bay 2.29 148 476 3 0.188 1,709 380,491 476

IR16

- 20 FL0021661 Vero

Beach 11.85 12,173 24,794 20 0.740 45,063

262,384 12,173

IR16

- 20 FL0042544 Ve ro Beach RO 2.39 2,438 2,985 4 0.5 6,092 2,985

IR16

- 20 FL0166511

IR CUD/ Hob a rt RO 1.90 2,221 2,759 3 0.750 6,853 2,759

IR16

- 20 FL0041637 IRCUD/

West Regional 0.73 1,397 2,838 1 4.0 12,184 2,838

IR16

- 20 FL0037940 I RCUD/ South County RO 1.51 3,752 4,636 3 1.5 13,707 4,636

IR21 N/A 15,890TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 56

Lagoon Segment NPDES Facility 2000

– 05 Flow Weighted

Concentration TN (mg/L) 1 Annu al Average Load

2001

– 05 TN

(lbs/yr) 2 95 th Percentile

Annual Load TN (lbs/yr) 3 Permit

Concentration TN (mg/L) 4 Permit

Flow Equiv. (MGD) 5 Permit

Annual

Load TN (lbs/yr) 6 TMDL TN (lbs/yr) 7 WLA TN (lbs/yr) 8

Banana River Lagoon

BR1

- 2 FL0042005 Morton

Salt 2.74 571 1214 N/A 0.084 N/A 116,314 1,214

BR3

- 5 FL0020541 Cape

Canaveral 1.05 1,342 2,151 3 1.8 16,448
123,434 2,151

BR3

- 5 FL0021105 Cocoa

Beach 6.27 1 2,476 18,446 12 1.5 54,676 4,022

BR6 N/A 30,661

BR7 N/A 21,347

Notes:

1. Average flow

- weighted nutrient concentration in the discharge summarized from monthly data reported to the Department by the facility. The 2000

– 05 period corresponds to the modeling period used by the SJRWMD for TMDL development.

2. Average annual nutrient load discharged by the facility from 2001

– 05. Loads are calculated from monthly discharge and monthly effluent nutrient concentration

, as reported by the facility to t he Department , with unit conversion factors. Annual loads are calculated from April to the following March to correspond with the modeling year used by the

SJRWMD. The average annual load is the average of the five annual loads. The five

- year period cor responds to the five

- year cycle of an NPDES permit.

3. The calculated 95 th percentile of the discharge's 5 annual nutrient loads.

4. The effluent nutrient concentration limit in the facility's NPDES permit. Provided for reference only ; not used in WLA calculati ons.
5. The permitted annual flow equivalent in the NPDES permit issued by the Department

. Some facilities are permitted to discharge only 60 or 91 days during the rainy season. The flow and number of discharge days allowed in the permit are multiplied alon g with conversion factors to calculate an annual flow equivalent. Provided so intermittent discharge facility flow can be compared with continuous discharge facilities. Provided for reference only ; not used in WLA calculations.

6. The annual load allowed by the facility's NPDES permit calculated by multiplying the permit discharge flow, the permit effluent nutrient concentration

, and conversion factors. Provided for reference only ; not used in WLA calculations.

7. The proposed TMDL (all point and nonpoint sourc es) for that lagoon segment calculated by the SJRWMD modeling approach (Steward and Green 2006) , plus direct atmospheric deposition

. 8. Proposed WLA for all point sources in that lagoon segment. Section 6.3.1 describes t he basis for specific allocations in m ore detail.

9. N/A represents the condition that a given lagoon segment does not have a point source discharger or, for a given facility, no permit limit for TN, TP, and/or flow.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 57 Table 6.4b. Permitted Annual TP Limits, Discharges, and WLAs for Facilities and TMDLs for Each Lagoon Segment

Lagoon Segment NPDES Facility 2000

- 2005 Flow Weighted

Concentration TP (mg/L) 1 Annual Average

Load

2001

– 05

TP (lbs/yr) 2 95 th

Percentile

Annual Load

TP (lbs/yr) 3 Permit

Concentration

TP (mg/L) 4 Permit

Flow Equiv. (MGD) 5 Permi t

Annual

Load TP (lbs/yr) 6 TMDL TP (lbs/yr) 7 WLA TP (lbs/yr) 8

North IRL

IRL1 -3 N/A 9,320

IR4 N/A 2,550

IR5 N/A 12,243

IR6 -7 FL0021521

Cocoa / J. Seller s 0.54 578 1,423 4.0 1.125 13,669

11,845 1,423

IR6 -7 FL0001473 Cape

Can averal PP N/A 146 146

IR6 -7 FL0000680 Reliant Energy

Indian River 0.20 12 40 N/A 0.297 N/A 40

IR8 FL0021571 Rockledge N/A 0 0 4.0 0.062 751 2,674 30

IR9

- 11 FL0043443

Melbourne RO 0.04 101 195 1.0 1.25 3,807 17,918 195

Central IRL

IR12 FL 0040622

BCUD /

South Beaches 1.50 13 36 4.0 0.123 1,502

43,170 36

IR12 FL0041122

Melbourne //

Grant Street 0.45 2 8 1.0 0.068 125 8

IR13 N/A 4,348

IR14

- 15 FL0042293 Barefoot Bay 0.35 22 78 1.0 0.188 570 64,076 78

IR16

- 20 FL0021661 Vero

Beach 1.06 916 1,411 6.0 0.740 13,518

52,141 916

IR16

- 20 FL0042544 Vero

Beach RO 0.34 340 487 4.0 0.5 6,092 487

IR16

- 20 FL0166511

IR CUD/ Hob a rt RO 0.04 45 96 1.0 0.750 2,284 96

IR16

- 20 FL0041637 0.04 81 159 0.1 4.0 1,218 159TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 58

Lagoon Segment NPDES Facility 2000

- 2005 Flow Weighted

Concentration TP (mg/L) 1 Annual Average

Load

2001

– 05

TP (lbs/yr) 2 95 th

Percentile

Annual Load

TP (lbs/yr) 3 Permit

Concentration

TP (mg/L) 4 Permit

Flow Equiv. (MGD) 5 Permi t

Annual

Load TP (lbs/yr) 6 TMDL TP (lbs/yr) 7 WLA TP (lbs/yr) 8

IRCUD/West

Regional

IR16

- 20 FL0037 940

IR CUD/South

County RO 0.04 112 291 1.0 1.5 4,569 291

IR21 N/A 1,458

Banana R iver Lagoon

BR1

- 2 FL0042005

Morton Salt 0.57 103 302 N/A 0.084 N/A 7,825 302

BR3

- 5 FL0020541 Cape

Canaveral 0.11 112 158 0.5 1.8 2,741
9,755 158

BR3

- 5 FL00 21105 Cocoa

Beach 1.32 2,291 3,599 4.0 1.5 18,226 1,063

BR6 N/A 3,247

BR7 N/A 2,426

1. Average flow

- weighted nutrient concentration in the discharge summarized from monthly data reported to the Department by the facility. The 2000

– 05 perio d corresponds to the modeling period used by the SJRWMD for TMDL development.

2. Average annual nutrient load discharged by the facility

, 2001

– 05. Loads are calculated from monthly discharge and monthly effluent nutrient concentration as reported by the

faci lity to the Department , with unit conversion factors. Annual loads are calculated from April to the following March to correspond with the modeling year used by the SJRWMD. The average annual load is the average of the five annual loads. The five

- year pe riod corresponds to the five

- year cycle of an NPDES permit.

3. The calculated 95 th percentile of the discharge's five annual nutrient loads.

4. The effluent nutrient concentration limit in the facility's NPDES permit. Provided for reference only ; not used in WL A calculations.

5. The permitted annual flow equivalent in the NPDES permit issued by the Department

. Some facilities are permitted to discharge only 60 or 91 days during the rainy season. The flow and number of discharge days allowed in the permit are mult iplied along with conversion factors to calculate an annual flow equivalent. Provided so intermittent discharge facility flow can be compared with continuous discharge facilities. Provided for reference only ; not used in WLA calculations.

6. The annual load allowed by the facility's NPDES permit calculated by multiplying the permit discharge flow, the permit effluent nutrient conc entration

, and conversion factors. Provided for reference only ; not used in WLA calculations.

7. The proposed TMDL (all point and no npoint sources) for that lagoon segment calculated by the SJRWMD modeling approach (Steward and Green 2006) , plus direct atmospheric deposition

. 8. Proposed WLA for all point sources in that lagoon segment. Section 6.3.1 describes t he basis for specific allo cations in more detail.

9. N/A in the table represents the condition that a given lagoon segment does not have a point source discharger or, for a given facility, no permit limit for TN, TP, and/or flow.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 59 existing long

- term average TP concentration o f the surface discharge is about 0.57 mg/L, which is significantly lower than the concentration observed before

the 1990s and meets the AWT requirement. Therefore, the 95 th percentile TP annual discharge load for 2001 through 2005, which is 1,423 lbs/yr, is assigned to the facility as its annual TP WLA

.

The long

- term TN concentration of the discharge is 5.78 mg/L, which is also significantly lower than the historic al discharge concentration, but does not m e et the AWT concentration requirement. Co nsidering that the 95 th percentile of the annual TN discharge rate from the facility is about 8,932 lbs/yr for the period from 2001 through 2005 ( more than 10 percent of the total allowable TN load for Segment IR6

- 7 [ 81,993 lbs/yr ] ), assigning the 95 th per centile annual TN load to the facility for its WLA was not considered sufficiently protective for the I RL

. Therefore, the long

- term average annual TN load for 2001 through 2005, which is 5,556 lbs/yr, is assigned to the facility as its annual TN WLA. The corresponding daily WLAs for TP and TN are 15.6 and 61.1 lbs/day, respectively, applicable to no more than 91 days in a given year.

(2) **Reliant Energy Indian River**  **Power Plant (FL0000680):** The vast majority of the discharge from the facility (maximum daily average of 820 MGD) into Segment IR6

- 7 is OTCW from the IRL . No extra TN and TP loadings are added through the recycled lagoon water. The only other surface water discharge from the plant is boiler blowdown, which has a maximum monthly average limi t of 0.297 MGD. The facility adds trisodium phosphate and disodium phosphate into the boiler blowdown to control pH. Therefore, a WLA of TP loading to the facility

is needed.

For the past 5 years, t he long

- term average TP concentration from the facility’s surface discharge has been about 0.20 mg/L , which meets the AWT concentration requirement. Therefore, the 95 th percentile of the existing TP discharge load , which is 40 lbs/yr, is assigned to the facility as its annual WLA. The corresponding d aily TP WLA is 0.1 lbs/day. As the facility does not discharge extra TN loading into the I RL , no WLA for TN is assigned to the facility.

(3) **Melbourne R O WWTF**  **(FL0043443):** The facility provides potable water to the city of Melbourne. It has a 1. 25

- MGD permitted design flow discharged to the Eau Gallie River, which in turn discharges into IRL Segment IR9

- 11. The surface discharge contains concentrated ground water constituents (brine) and

TN and TP. The facility ’s existing long

- term discharge TN and TP

concentration s are 2.43 and 0.04 mg/L

, respectively, which meet the AWT requirement s for both TN and TP

. Therefore, the 95 th percentile TN and TP annual discharge loads for 2001 through 2005, which are 9

, 170 lb s /yr for TN

and 195 lb s /yr for TP, are assig ned to the facility as its annual WLAs. The corresponding daily WLAs for TN and TP are 25.1 and 0.5 lbs/day, respectively.

(4) **B CUD**  **/**

**South Beaches WWTF (FL0040622):** The facility has a n 8. 0

- MGD ADF discharge permit. T reated wastewater is injected into an underground injection well system most of the time . The facility’s wastewater permit only allows surface discharges of the same ADF discharge limit for 5 days in a 5

- year permitTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 60 cycle when the mechanical integrity test is conducted for the underground

in

ject ion well system. F rom 200 1 through 2005, the 95 th percentile TN and TP discharge rate s were about 173 and 36 lbs/yr, respectively. Compared with the total allowable TN load of 226,361 lbs/yr and TP load of 42,376 lbs/yr for the segment, the TN and TP load s from the facility are considered insignificant. Therefore, even though the long

- term discharge TN and TP concentration s of the facility are 8.09 and 1.50 mg/L

, respectively, which are higher than the AWT

level s

, the 95 th percentile TN and TP discha rge s for the 2001

– 05 period , which

are 173 and 36 lbs/yr

, respectively, are assigned to the facility as its TN and TP

annual WLA s

. The corresponding daily WLAs for TN and TP are 34.6 and 7.2 lbs/day, respectively, applicable only to the 5

- day mechanical i ntegrity test in a given permit cycle.

(5) **Melbourne/Grant Street WWTF (FL0041122):** The 5. 5

- MGD AADF permitted capacity for treated wastewater is either disposed of in a Class I underground injection well or directed to a public access reuse system. Th e surface discharge to Crane Creek, which in turn discharges into I RL Segment IR12, is only allowed for a 5

- day period in a 5

- year permit cycle during the mechanical integrity test of the underground injection well. The long

- term average TN and

TP concent rations for the surface discharge from the facility are 10.78 and 0.45 mg/L , respectively . Although the TN discharge concentration does not meet the AWT concentration requirement, the 95 th percentile of the annual TN discharge rate is about 182 lbs/yr for 2001 through 2005, which is considered insignificant compared with the segment’s total allowable TN load (226,361 lbs/yr). Therefore, the 95 th percentile TN and TP annual discharge loads for the period from 2001 through 2005, which are 182 lbs/yr for TN and 8 lbs/yr for TP, are assigned to the facility as its annual WLAs. The corresponding daily WLAs for TN and TP are 36.4 and 1.6 lbs/day, respectively, applicable only to the 5

- day mechanical integrity test in a give n permit cycle.

(6) **Barefoot Bay Adv anced W**  **WTF (FL0042293):**  The majority of treated wastewater from the facility is used for irrigating golf course s , sod farm s , and citrus groves at or near the Barefoot Bay Mobile Home Community. The

intermittent wet

- weather discharge is only allowed for l ess than 91 days (or the equivalent of 2,184 hours) per year

, and the average daily discharge rate during

th at period should not exceed 0.75 MGD . The long

- term average TN and TP discharge concentrations for the facility are 2.29 and 0.35 mg/L, respectivel y, which both meet the AWT concentration requirements. Therefore, the 95 th
percentile TN and TP annual discharge loads for 2001 through 2005, which are 476 lbs/yr for TN and 78 lbs/yr for TP, are assigned to the facility as its annual

WLAs. The correspon ding daily WLAs for TN and TP are 5.2 and 0.9 lbs/day, respectively, applicable to no more than 91 days for each year.

(7) **Vero Beach WWTF (FL0021661):** The majority of the treated wastewater from the facility is directed to a slow

- rate public access reus e system that is used to irrigate recreation areas, residential lawns, golf courses, urban landscapes, and

road medians in the Reuse Service Area. The wet

- weather intermittent discharge to the I RL at Segment IR16

- 20 is only allowed for no more than 60 day s (or the equivalent 1,440 hours) per year

, and the average daily discharge during the period should not exceed 0.740 MGD. The long

- term average TN and TP concentrations for the discharge are 11.85 and 1.06 mg/L, respectively,TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 61 which exceed the AWT concent ration requirements. Considering that the 95 th
percentile TN and TP loadings for the facility from 2001 through 2005 are 24,794 and 1,411 lbs/yr, respectively, which are significant, the long

- term average

annual discharge loads of TN and TP from 2001 thro ugh 2005, which are 12,173 lbs/yr for TN and 916 lbs/yr for TP, are assigned to the facility as its annual

WLAs. The corresponding daily WLAs for TN and TP are 202.9 and 15.3 lbs/day, respectively, applicable to no more than 60 days in each year.

(8) **Ver o Beach R**  **O**

**– Potable Water Treatment Plant (FL0042544):**  The facility

has a 0. 5

- MGD permitted surface water discharge for its ground water concentrate (brine) to the Indian River Farm Control District Main Canal, which in turn discharges to the IRL at Segmen t IR16

- 20. The long

- term average TN and TP discharge concentrations for the facility are 2.39 and 0.34 mg/L, respectively, which meet both the TN and TP AWT concentration requirements. Therefore, the 95 th percentile TN and TP annual discharge loads for 2 001 through 2005, which are 2,985 lb s /yr for TN and 487 lb s /yr for TP, are assigned to the facility as its annual WLAs. The corresponding daily WLAs for TN and TP are 8.2 and 1.3 lbs/day, respectively, applicable for the entire year.

(9) **I RCUD**  **/Hobart Pa rk Demineralization Concentration Discharge**  **(FL0166511):** The facility has a 0. 75

- MGD permitted capacity discharge to the

I RL at Segment IR16

- 20 for its ground water concentrati o n (brine). The long

t erm average TN and TP discharge concentrations for the fa cility are 1.90 and 0.04 mg/L, respectively, which meet both the TN and TP AWT concentration requirements. Therefore, the 95 th percentile TN and TP annual discharge loads for 2001 through 2005, which are 2,759 lbs/yr for TN and 96 lbs/yr for TP, are assig ned to the facility as its annual WLAs. The corresponding daily WLAs for TN and TP are 7.6 and 0.3 lbs/day, respectively, applicable for the entire year.

(10) **I RCUD**  **/West Regional WWTF (FL0041637):** The facility has a 4. 0

- MGD permitted discharge capacity t o the Vero Beach Main Canal, which in turn discharges to the I RL at Segment IR16

- 20. The long

- term average TN and TP discharge concentrations are 0.73 and 0.04 mg/L, respectively, which meet both the TN and TP AWT concentration requirements. Therefore, t he 95 th percentile TN and TP annual discharge loads for 2001 through 2005, which are 2,838 lbs/yr for TN and 159 lbs/yr for TP, are assigned to the facility as its annual

WLAs. The corresponding daily WLAs for TN and TP are 7.8 and 0.4 lbs/day, respective ly, applicable for the entire year.

(11) **I RCUD**  **/South County R O** 

**– Potable Water Treatment Plant (FL0037940):**  The facility has a 1. 2

- MGD permitted average daily discharge capacity to the Indian

R iver C ounty South Relief Canal, which in turn discharges to the I RL at Segment IR16

- 20. The long

- term average TN and TP discharge concentrations are 1.51 and 0.04 mg/L, respectively, which meet both the TN and TP AWT concentration requirements. Therefore, the 95 th percentile TN and TP annual discharge loads for 2001 t hrough 2005, which are 4,636 lbs/yr for TN and 291 lbs/yr for TP, are assigned to the facility as its annual WLAs. The corresponding daily WLAs for TN and TP are 12.7 and 0.8 lbs/day, respectively, applicable for the entire year.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 62 (12) **Morton Salt Industri al Wastewater Treatment and Disposal System**  **(FL0042005) :**  The facility

, located in Port Canaveral

, has a 0. 084

- MGD average daily flow process wastewater discharg e to a turning basin, which is connected

to the Banana River Lagoon at Segment BR1

- 2 through a boat lock. The long

term average TN and TP discharge concentrations for the facility are 2.74 and 0.57 mg/L, respectively, which meet both the TN and TP AWT concentration requirement. Therefore, the 95 th percentile TN and TP annual discharge loads

for 20 01 through 2005, which are 1,214 lbs/yr for TN and 302 lbs/yr for TP, are assigned to the facility as its annual WLAs. The corresponding daily WLAs of TN and TP are 3.3 and 0.8 lbs/day, respectively, applicable for the entire year.

(13) **Ca pe Canaveral W**  **RF (FL0020541):**  The facility has a 1. 80

- MGD AADF permitted discharge to the Banana River at Segment BR3

- 5. The long

- term average TN and TP discharge concentrations are 1.05 and 0.11 mg/L, respectively, which meet both the TN and TP AWT concentration require ments. Therefore, the 95 th percentile TN and TP annual discharge loads for 2001 through 2005, which are 2,151 lbs/yr for TN and 158 lbs/yr for TP, are assigned to the facility as its annual WLAs. The corresponding daily WLAs of TN and TP

are 5.9 and 0.4 lbs/day, respectively, applicable for the entire year.

WLAs are assigned to the following facilities using methods that are different from the one

described above:

(1) The **R ockledge WWTP (FL0021571)**  is known to discharge a very small load of

TN and TP ( about 10 lbs/yr of TN and TP) only when it performs m echanical

i ntegrity t esting

. The last time Rockledge had a discharge during this testing

was in 1996

– 97. The facility is allocated limits of 30 lbs/yr for both TN and TP

as its annual WLAs , an amount s ufficient for this purpose. The corresponding daily WLAs for TN and TP are both 6.0 lbs/day, applicable to the 5

- day mechanical integrity test in any given permit cycle.

(2) The **Cape Canaveral Power Plant (FL0001473)** is allocated its currently permitted loads for TN and TP (146 lbs/yr TP and 2555 lbs/yr TN) ; as no TN and TP permit limits were applied to the surface discharge of the facility before 2005

, no monitoring data can be used to calculate long

- term statistics for TN and TP discharge loadings from the facility. The current permit limits for the facility are annual average daily loads of 7 lb s /day for TN and 0.4 lb s /day for TP, which correspond s to 2

, 555 lbs/yr for TN and 146 lbs/yr for TP. As the percentage s of

TN and TP contributions from the fac ility are fairly low in the total TN and TP loadings to the lagoon segment

, even when the facility discharges at its current permit level ( 3 percent for TN and 1 percent for TP)

, the facility’s permit TN and TP loadings are used as the WLA s in this TMDL

.

( 3) As discussed above, t he **Cape Canaveral WWTP (FL0020541)** is allocated the

95 th percentile of its annual load as a maximum limit because it has low effluent

concentrations and loads (0.11 mg/L and 1 61 lbs/yr for TP, and 1. 05 mg/L and

1475 lbs/yr for TN). However, the Cocoa Beach WWTP (FL00211005), which discharges to the same lagoon segment as the Cape Canaveral WWTP, has much higher effluent concentrations (6. 3 mg/L TN and 1.3 mg/L TP) and much higher loads ( 13

, 652 lbs/yr of TN and 2

, 622 lbs/yr of TP). After reserving theTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 63 allocation for Cape Canaveral, Cocoa Beach was allocated annual load lim i ts for

TN and TP that result in 15 percent of the TMDL for S egment BR3

- 5 being allocated for point sources, with the other 85 percent allocated for nonpoint

sourc es.

Table s 6. 3 a and 6. 3 b summarize the WLAs of TN and TP , respectively, assigned to each facility. Although the loads currently contributed by NPDES

- permitted facilities are generally a

small fraction of the total annual external load of nutrients to the lagoon, most facilities have permit limits that are much higher than their current discharges. In some cases, the difference

is ten fold, twenty fold

, or even a hundred fold. If all of these facilities were to discharge at their present permit limits, the i r contribution would become much more significant and could offset gains made by reducing nonpoint sources. This is especially true of Segment BR3

- 5. In fact, the present permits for the two facilities in BR3

- 5 exceed the entire TMDL

, including the

nonpo int source allocation for this lagoon segment.

It should be noted that , for those domestic wastewater facilities whose discharges are influenced by the rainfall condition

— f or example

, inflow and infiltration (I&I) issues for a domestic wastewater treatmen t plant, and reduced irrigation demand for a public access reuse
system

— wastewater permitting is primarily based on the long

- term average rainfall condition. In implementing the se TMDLs, the Department will take into consideration rainfall condit ion s that are above the long

- term average.



### 6.3.2 N **PDES Stormwater Discharges** 

Because no information was available to the Department at the time this analysis was conducted regarding the boundaries and locations of all the NPDES stormwater dischargers,

the exact s tormwater TN and TP loadings from MS4 areas were not explicitly estimated

. The

wasteload allocations for each of the MS4s are the same percent TN and TP reduction s required for the LA assigned to the nonpoint sources in the river segments that belong to e ach county and municipality. Table 4.5 lists t he MS4 permits that will be influenced by the TMDLs covered in this report

. It should be noted that any MS4 permittee is only responsible for reducing the loads associated with stormwater outfalls that it own s or otherwise has responsible control over, and it is not responsible for reducing other nonpoint source loads in its jurisdiction.



### 6.4 Margin of Safety

Consistent with the recommendations of the Allocation Technical Advisory Committee ( Department , 2001 ), an implicit MOS was used in the development of this TMDL. An implicit MOS was provided by the conservative decisions associated with a number of modeling assumptions, the development of site

- specific alternative water quality targets, and the developme nt of assimilative capacity.

The IRL TMDLs were developed using an implicit MOS

. The sublagoon targets for TN and TP

are set to achieve within

- 10 percent of the maximum seagrass depths documented in each segment of the IRL between 1943 and 1999. Exce pt for TN in the Central IRL , these TMDLs are similar to the loading estimates for 1943, when human alteration of the watershed was fairly

minimal. The estimated TP load for the Central IRL in 1943 is higher than its target. However, an implicit MOS is p rovided by the presence of Sebastian Inlet, which did not exist in 1943

, butTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 64 today provides flushing to the Central IRL sublagoon

, lessen ing the impact of pollutant loads. In addition, estimating the needed percent reduction by focusing on the loadings fr om the

watershed resulted in a higher needed percent reduction than including the atmospheric deposition into the calculation, which also adds to the MOS

.



### 6.5 Recommendations for Further Studies

TMDLs for the IRL and Banana River L agoon segments covered in this report are developed based on the correlation between watershed loading and seagrass depth limit. Nutrient targets are developed as loading targets. No nutrient concentration targets are explicitly developed in

this TMDL

, although the per

- acre nu trient loading s from the watershed impl y the nutrient

concentrations from the watershed. The SJRWM D is currently working on defining concentration targets for the estuarine segments of the IRL . These targets include TN and TP, as well as other parameters

, and are being developed from the median concentrations observed where seagrass depth limits are within the

- 10 percent departure (shoreward) from their full

restoration levels.

Th e project is still in progress, but it suggests TN concentrations of 0.9 8 mg/L based on 12

- month medians, or 1.0 mg/L based on 18

- month medians. For TP, the 12

- month median is 0.05 mg/L, and the 18

- month median is 0.06 mg/L (Steward and Green 2006). Having target nutrient

concentrations for these waters can facilitate evalua ting the effectiveness of nutrient removal in

the watershed

, because it is easier to measure nutrient concentrations than to directly measure the nutrient loading s from the watershed.

In addition to directly measur ing the TN and TP concentrations in the lagoon segments that have already achieved seagrass depth limits, studies on the processes that influence nutrient dynamics in these lagoon segments will be instrumental in interpreting nutrient concentration s in these waters. For example, if a low nutri ent concentration is observed, it is important to understand whether it means a high uptake rate from per i phyton or low nutrient watershed loading.

Another issue that deserves further study is the dynamics of DO concentration s in the lagoon.
For now, how the recovery of seagrass es will influence DO concentration s in the lagoon is not completely understood. Studies have shown that certain development al stage s of seagrass

communities and at certain season s , seagrass es may show net DO consumption instead of DO

enrichment

. Th at is why this TMDL only addresses the DO depression resulting from human activities that are pollutant related , b ut it is not feasible to identify the expected DO target after the full restoration of seagrass targets is achieved in thes e waters. An improved understanding

o f how seagrass influences DO concentrations in these lagoon waters will help to answer this question.

Understanding how pollutant sources other than human land use s influence nutrient loadings into the lagoon system w ill facilitate the implementation of these TMDLs. T he TN and TP loadings from the I RL and Banana River Lagoon watershed s were estimated primarily based on

land use and soil type. Especially for urban areas, watershed loadings estimated using this

method are lumped loadings that may include many potential sources

, such as septic tank s

, sewer line leakage, resident ial fertilization, the reuse of treated wastewater, etc. Contribution s from these sources were not quantified explicitly in this TMDL report due to the lack of local data. However, during the TMDL implementation stage, information regarding the load

contribution from each individual source will be evaluated

.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 65 

# Chapter 7: NEXT STEPS: IMPLEMENTATION PLAN

DEVELOPMENT AND BEYOND

7.1 Basin Managem ent Action Plan

Following the adoption of this TMDL by rule, the next step in the TMDL process is to develop an implementation plan for the TMDL, referred to as the BMAP. This document will be developed over the next two years in cooperation with local st akeholders, who will attempt to reach consensus on detailed allocations and on how load reductions will be accomplished. The BMAP will include, among other things:

**•** Appropriate load reduction allocations among the affected parties ;

**•** A description of the lo ad reduction activities to be undertaken, including structural projects, nonstructural BMPs , and public education and outreach ;

**•** A description of further research, data collection, or source identification needed in

order to achieve the TMDL ;

**•** Timetables for implementation ;

**•** Confirmed and potential funding mechanisms ;

**•** Any applicable signed agreement(s );

**•** Local ordinances defining actions to be taken or prohibited ;

**•** Any applicable local water quality standards, permits, or load limitation agreements ;

**•** Milestones f or implementation and water quality improvement ; and

**•** Implementation tracking, water quality monitoring, and follow

- up measures

.

An assessment of progress toward the BMAP milestones will be conducted every five years,

and revisio n s to the plan will be mad e as appropriate, in cooperation with basin stakeholders.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 66 

# References

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. Technical Memorandum No. 50 . Palatka, FL: St. Johns Ri v er Water Management District.

Barna, M.G, M.A. Rodriguez, T. Moore, W.C. Malm, K.A. Gebhart, and B.A. Schichtel. 2008.

Predict ing dry deposition of total nitrogen at Rocky Mountain National Park. In p ress.

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. Hydrological

Simulation Program

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Water Resources Division, Reston, VA.

C DM . 2003. Crane Creek watershed monitoring report. Hydrologic and hydrodynamic continuing services contract with the St. Johns River Management Di strict

, Palatka, FL.

Christian, D. November 16, 2004. Indian River Lagoon flushing. T echnic a l memorandum prepared for the St. Johns River Water Management District, Palatka, F L.

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of water and wastewater

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. Hertfordshire, UK: Ellis Horwood

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. Assessment of bulk atmospheric deposition to the Tamp a Bay watershed

. Tampa Bay National Estuary Program Technical Publication #08

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Florida Department of Environmental Protection 67 Tallah assee, F L : Bureau of Watershed Management, Division of Water Resource Management.

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, and J.C. Zieman. 1991. Photosynthesis, respiration and whole plant carbon budgets of Thalassia testudinum, Halodule wrightii and Syringodium filiforme. I n W.J. Kenworthy and D.E. Haunert (eds.)

, The light requirements of seagrasses: P roceedings of a workshop to examine the capability of water quality criteria, standards and monitoring
programs to protect seagrasses ( NOAA Technical Memorandum NMFS

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Gallegos, C.L. 1994. Refining habitat requirements of submersed aquatic vegetation

– role of optical models. Estuaries 17: 189

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Gallegos, C.L., and W.J. Kenworthy. 1996. Seagrass depth limits in the Indian River Lagoon (Florida, U.S .A.): Application of an optical water quality model. Estuarine, Coastal and Shelf Science 42, 267

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288.

Green, W.C.

, and J.S. Steward. January 2003. The utility of a pollutant load screening model in determining provisional pollutant load reduction go als. In U.S. EPA Technology Transfer

Conference: Emerging technologies

, tools , and techniques to manage our coasts in the

21 st century

. Plenary synthesis session. Cocoa Beach, FL

Hanisak, M.D. 2001. Photosynthetically active radiation, water quality, and submerged aquatic vegetation in the Indian River Lagoon. Final report for Contract 93W199, St. Johns River Water Management District, Palatka, F L.

Harper, H.H.

, and D.B. Baker. 2003. Evaluation of alternative stormwater regulations for

southwest Flo rida. Submitted to Water Enhancement & Restoration Coalition, Inc. Prepared by Environmental Research & Design, Inc.

Hendry, C.D., P.L. Brezonik, and E.S. Edgerton

. 1981

. Atmospheric deposition of nitrogen and phosphorus in Florida. In S.J. E isenreich (ed.)

, Atmospheric pollutants in natural w aters (Ann Arbor, MI: Ann Arbor Science, pp. 199

– 215 )

.

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, M.J., S.B. Bricker, W.C. Dennison, P.M. Glibert, R.J. Livingston, K.A. Moore, R.T. Noble, H.W. Paerl, J.M. Ramstack, S. Seitzinger, D.A. Tomasko, an d I

. Valiela. 2007. Barnegat Bay

- Little Egg Harbor estuary : Case study of a highly eutrophic coastal bay
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– S16.

Martin, J.B., J. Jaeger, and J. Cable. 2004. Quantification of advective benthic processes

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, and M. Bergman. 1998. The P ollution L oad S creening M odel : A tool for t he 1995 district water management plan and the 1996 local government water resource atlases.

Technical Memorandum No. 29. Palatka, FL: Department of Water Resources, St. Johns River Water Management District

.

Phlips, E.J., S. Badylak, and T. Grosskopf. 2002. Factors affecting the abundance of phytoplankton in a restricted subtropical lagoon, the Indian River Lagoon, Florida, USA. Estuarine, Coastal and Shelf Science 55: 385

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, R. Pribble, and H. Greening. 2001. Direct wet and dry deposit ion of ammonia, nitric acid ammonium and nitrate to the Tampa Bay Estuary, FL, USA. Atmospheric Environment

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Russell, K.M., W.C. Keene, J.R. Maben, and J.N. Galloway. 2003. Phase partitioning and dry deposition of atmospheric nitrogen at the mid

- Atlantic U. S. Coast. J. of Geophysical Res 108(D21): 1

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, Palatka, F L

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.

Steward, J. S

. , and W.C. Green. 2006. Setting pollutant loading targets for the Indian River and

Banana River L agoons based on relatio nships between loadings and seagrass depth limits. St. Johns River Water Management District.

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, and W.C. Green. 2007. Setting load limits for nutrients and suspended solids based upon seagrass depth

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Steward J.S., R. Brockmeyer, R. Virnstein, P. Gostel, P. Sime, and J. VanArman. 2003. Indian River Lagoon Surface Water Improvement and Management (SWIM) Plan, 2002 update. St. Johns River Water Management District, Palatka, FL, and South Fl orida Water Management District, West Palm Beach, FL.

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. Memorandum from Benjamin H. Grumbles, Assistant Administrator

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.

———

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Press.TMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 70 

# Appendices

Appendi x A: Background Information on Federal and State Stormwater Programs

In 1982, Florida became the first state in the country to implement statewide regulations to address the issue of nonpoint source pollution by requiring new development and redevelopment to treat stormwater before it is discharged. The Stormwater Rule, as authorized in Chapter 403, F.S., 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. In 1994, the Department’s stormwater treatment requirements were integrated with the stormwater flood control requirements of the state’s water management districts, along with wetland protect ion requirements, into the Environmental Resource Permit regulations.

Chapter 62

- 40, F.A.C., also requires the water management districts to establish stormwater pollutant load reduction goals (PLRGs) and adopt them as part of a Surface Water Improvement and Management ( SWIM ) 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, th e Everglades, Lake Okeechobee, and Lake Apopka. No PLRG had been developed for Newnans Lake when this report was published.

In 1987, the U.S. Congress established Section 402(p) as part of the federal Clean Water Act

Reauthorization. This section of th e law amended the scope of the federal NPDES permitting program to designate certain stormwater discharges as “point sources” of pollution. The EPA promulgated regulations and began implementing the Phase I NPDES S tormwater P rogram in

1990. These stormwa ter discharges include certain discharges that are associated with industrial activities designated by specific standard industrial classification (SIC) codes, construction sites disturbing 5 or more acres of land, and the master drainage systems of local governments with a population above 100,000, which are better known as MS4s. However, because the master drainage systems of most local governments in Florida are interconnected, the EPA implemented Phase I of the MS4 permitting program on a countywide ba sis, which brought in all cities (incorporated areas), Chapter 298 urban water control districts, and the Florida Department of Transportation throughout the 15 counties meeting the population criteria. EPA authorized the Department to implement the NPDES Stormwater Program (with the exception of Indian lands) in October 2000

.

An important difference between the federal NPDES and the state’s stormwater/environmental resource permitting programs is that the NPDES Program covers both new and existing

disch arges, while the state’s program focuses on new discharges only. Additionally, Phase II of the NPDES Program, implemented in 2003, expands the need for these permits to construction sites between 1 and 5 acres, and to local governments with as few as 1,00 0 people. These revised rules require that these additional activities obtain permits by 2003.

While these urban stormwater discharges are now technically referred to as “point sources” for the purpose of regulation, they are still diffuse sources of pol lution that cannot be easily collected and treated by a central treatment facility , as are other point sources of pollution such as domestic and industrial wastewater discharges. It should be noted that all MS4 permitsTMDL Report: Indian River Lagoon and Banana River Lagoon, Nutrients and DO, March 20 09

Florida Department of Environmental Protection 71 issued in Florida include a reopener clause that allows permit revisions to implement TMDLs when the implementation plan is formally adopted.Florida Department of Environmental Protection

Division of Water Resource Management

Bureau of Watershed Management

2600 Blair Stone Road, Mail Station 3565

Tallahassee, Florida 32399

- 2400
www2.dep.state.fl.us/water/