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# Lake Okeechobee Surface Water Improvement and Management (SWIM) Plan
Planning Document

July 2002 Draft
prepared by 

## South Florida Water Management District West Palm Beach, FloridaLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Executive Summary

i 

## EXECUTIVE SUMMARY

This document provides an overview of the acti vities and accomplishments that have been directed towards the restorati on of Lake Okeechobee since adoption of the Surface Water Improvement and Manageme nt (SWIM) Plan - Update for Lake Okeechobee (SFWMD, 1997a). This update also describes th e current and proposed activities through 2000.
Lake Okeechobee and its watershed are key components of South Florida's Kissimmee-Okeechobee-Everglades ecosystem, wh ich extends from the headwaters of the Kissimmee River in the north to Florida Bay in the south. The lake provides a number of ecological and societal values. It is home to one of the nation's prized bass and speckled perch fisheries, as well as an economically important comm ercial fishery. At the same time, it provides habitat for a wide variety of wading birds, migratory waterfowl, and the federally-endangered Everglades Snail Kite. La ke Okeechobee is also a source of drinking water for cities and towns along the lake, and can be a backup water supply for the communities of the lowe r east coast of Florida. The lake also supplies irrigation water for the expansive Everglades Agricultural Area, and is a critical s upplemental water supply for the Everglades. The Lake Okeechobee SWIM pl anning area has been defi ned as the major basins that are direct tributaries to the lake, including those ba sins that are hydrologically upstream and/or from which wate r is presently released or pumped into the lake on a regular basis. Although the Lake Okeechobe e SWIM planning area generally excludes basins that are hydrologically downstream and act primarily as receiving basins for water supply (Caloosahatchee and St. Lucie River), the conveyance of flood control discharges and the resulting potential associated e nvironmental impacts ma ke these basins a component of this plan. The SWIM Act (Section 373.451-.459, Florida Statutes, [F.S.]), adopted by the Florida Legislature in 1987, requires water management districts, in conjunction with other state agencies and local governments, to prepare SWIM Plans for priority water bodies, including Lake Okeechobee. The SWIM Act requires that the plans describe strategies and potenti al programs for restoring or pr otecting the water body to Class III standards or better for r ecreation, propagation and mainte nance of a healthy, wellbalanced population of fish and wildlife. The plan must include a listing of studies that are being or have been prepared for the wate r body; a description of the research and feasibility studies that will be performed to determine the pa rticular strategy or strategies to restore or protect the water body; a descript ion of the measures needed to manage and maintain the water body once it has been restored and to pr event future de gradation; a schedule for restoration and pr otection of the water body; and an estimate of the funding needed to carry out the restor ation or protection strategies. The SWIM Act sets forth a specific pr ocess for the preparation, review, and approval of SWIM Plans. Itrequires the South Florida Water Management Districtii Executive Summary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
(SFWMD or District) to deve lop SWIM plans in cooperation with the Florida Department of Environmental Protection (FDEP) and other agencies. Pursuant to Section 373.455, F.S., the District submits a dr aft plan to the FDEP and othe r agencies. The FDEP reviews the cost of the SWIM Plan, funding availabi lity, and the likelihood that the plan will significantly improve or protect water quality and associ ated natural resources. If the FDEP determines that a SWIM plan does not meet minimum plan requirements, it shall recommend to the District modifications or additions to the planpursuant to Section 373.456(1), F.S. Other agencies review the plan for its effects on the resources within their respective jurisdictions and make recommendations. SWIM plans must be consistent with st ate water policy as outlined in Chapter 62-40, Florida Administrative Code (F.A.C), and to othe rwise provide guidance to the FDEP and the water management districts in the development and preparation of water management programs, rules, and plan s. Chapter 62-40.432 requires the water management districts to develop pollution lo ad reduction goals (PLRGs) for SWIM water bodies. The PLRG developed for Lake Okeechobee was a 40 pe rcent reduction in phosphorus loading from the watershed, based on the conditions thatexisted from 1973 to 1979 (Federico et al., 1981), withan expected dow nstream benefit of maintaining the trophic state and the biolog ical integrity of the lake. To as sist in achieving this goal, total phosphorus concentrations in runoff leavin g land parcels were limited by the Lake Okeechobee Works of the District (WOD) Rule. The total phosphorus concentration targets range from 0.18 to 1.2 milligrams per liter (mg/l). The federal Clean Water Act (Title 33, Chapter 26, Subchapter III, Section 1313(d)), requires that each st ate develop total maximum da ily loads (TMDLs) for each water-quality-limited segment reported. A TMDL reflects the total pollutant loading, from all contributing s ources, that a water segment can r eceive without excee ding its capacity to assimilate the pollutant loads and still meet applicable water qua lity standards. The phosphorus TMDL established fo r Lake Okeechobee is 140 metr ic tons (based on a 5-year rolling average) to achieve an in-lake ta rget phosphorus concentration of 40 parts per billion in the pelagic zone of the lake (FDEP 2000). The restoration target was determined using computer models deve loped based on past resear ch performed by the SFWMD using SWIM funds. This target will support a healthy lake system, restore the designated uses of Lake Okeechobee, and allow the lake to meet applicable water quality standards. The 1997 SWIM plan update reported that phosphorus load reductions had occurred, but the 40 percent reduction in loads was not ac hieved. It recommended the implementation of programs and projects to improve the la ke and watershe d water quality situation. The status of thes e programs and projects are summarized in this update. Even with the implementation of these programs and projec ts, nutrient loads to Lake Okeechobee have not decreased signifi cantly. The highest inflow phosphorus concentrations continue to be found in the S-154 and S- 191 basins where dairies are abundant and the majority of the out-o f-compliance WOD site s are found. Phosphorus loading is far in excess of the amount considered for a he althy Lake Okeechobee ecosystem and current model da ta predict that it may take decades before in-lake phosphorus concentrations will res pond to reduced external loads.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Executive Summary

iii Several major accomplishments have been ma de in the restoration effort since the publication of the last SWIM plan update in 1997. One of th e most important restoration actions was the Lake Okeechobee Managed Recession Operation. During six years prior to 2000, high water levels in the lake (associ ated with a prolonged wet period) destroyed nearly all of the lake’s subm erged plant beds and caused ex tremely poor water quality. The lake’s prize bass fishery wa s on the brink of ecological co llapse. A period of low water levels (less than 13 feet, lasti ng for at least 8 weeks) was requi red to allow recovery of the biological communities. In Ap ril and May 2000, approximatelyone foot of water was released from Lake Okeechobee. Coincident withthat, another one foot of water left the lake for normal water supply deli veries to agriculture and othe r uses, and one foot left the lake by direct evaporation into the atmosphere. Taken together the lake dropped by approximately 3 feet between April and July. As a result of the low water levels, Lake Okeechobee quickly recovered fr om its previously stress ed condition. Over 45,000 acres of new submerged plant beds grew during the summer and fa ll and the lake’s nearshore bulrush community (prime bass habitat) ex panded. The low water levels also allowed coordinating state and federal agen cies to carry out controlled fi res that have killed tens of thousands of acres of exotic plants that were taking over valuable wildlife habitat. A new regulation schedule for the lake was formally a dopted by the United States Army Corps of Engineers (USACE) in July 2000. This schedule, the Water Supply and Environment (WSE) schedule uses climate forecasting to dete rmine the volumes of water to release from the lake unde r flood control circumstances, and has the potential to provide environmental benefits for the lake and downstream systems while not sacrificing water supply. The extent of the benefits will depe nd in part on specific adaptive management protocols that are presently be ing developed by the District.
Restoration efforts for La ke Okeechobee were recently advanced with the passing of the Water Resources Developmen t Act of 2000 (WRDA 2000). The WRDA 2000 authorizes the Comprehensive Everglades Restoration Plan (CERP). The CERP is expected to have substa ntial effects on the lake's hydropatte rn. It is expect ed to reduce the number of extreme high and low events an d increase the occurrence of ecologically beneficial spring recession events. The act al so authorizes projec ts that will reduce nutrient loads to the lake. These components include regional stormwater treatment areas, reclamation of isolated wetlands, and regional water storage facilities, such as aquifer storage and recovery wells and reservoirs.
The enactment of the Lake Okeechobee Protection Ac t (LOPA) (Section 373.4595, F.S.) in 2000 also advanced restoration efforts. This act provides an umbrella that captures many lake restoration efforts. It will si gnificantly enhance mandates restoring and protecting the lake using a phased, wate rshed-based approach to reduce phosphorus loading to the lake and downstream receiving wate rs. Fulfilling this act will require a great deal of cooperation among governme nt agencies and the public. To facilitate the execution of the Lake Okeechobee Protection Plan, aninteragency committee was formed with individuals from the FDEP, the Florida Department of Agriculture and Consumer Services, and the SFWMD. The agencies are currently planning and implementing numerous management activitie s in the watershed to reduce phosphorus loading to the lake. These include the construction of surf ace water storage rese rvoirs and stormwateriv Executive Summary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

treatment areas; the restorati on of isolated wetlands the development and implementation of best management practices to control nonpoint sources of pollution; the continuation of research and monitoring to en sure the projects are designe d and implemented to optimize success; the removal of phosphorus-rich sedi ment from tributaries to Lake Okeechobee; and the implementation of a se diment management feasibilit y study to determine whether or not it is feasible to reduce internal lo ading from the lake se diments. More current information regarding the status of th e LOPA activities can be found in the Lake Okeechobee Protection Program A nnual Report to the Legislature (SFWMD, 2001a, 2001b). This update of the Lake Okeechobee SWIM Plan has set goals for the Lake Okeechobee SWIM planning area in the areas of water quality; environmental resources; flood protection and water suppl y; recreation, navigation, and public involvement; and intergovernmental coordination. Objectives have been deve loped to accomplish these goals. Programs and projects ar e being developed and will be implemented to achieve these objectives. The goals an d objectives, as well as some of the programs and projects are summarized below. 

### Phosphorus Load Reduction in the Tributaries In an effort to meet the propos ed TMDL target and in-lake phosphorus concentration of 40 parts per billion and ac hieve a phosphorus load of 140 tons per year, over-target phosphorus loading must cont inue to be reduced. The expanded WOD program, the new Lake Okeec hobee Protection Plan, and othe r new programs and projects are being implemented to achieve the inflow target are summarized in Chapter 2 and itemized below: • Best available technologies to significantly re duce the export of phosphorus from dairy operations into tributaries and Lake Okeechobee • Reservoir-assisted stor mwater treatment areas • Critical restoration projects • Isolated wetlands restoration • Natural resource economic analys is of a wide range of phosphorus control alternatives, using full-cost accounting practices • Sediment removal technolog ies in the tributaries • Research and modeling efforts to determine source of loads and methods to reduce themLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Executive Summary

v 

### Reduction of Nonnutrient Pollutant Loads To reduce the nonnutrient pollutant loads, Class I Water Quality Standards (potable water supplies) must be achieved within Lake Okeechobee and Cl ass III Water Quality Standards must be achieved within the lake tributaries. To achieve the in-lake reduction, the following initiatives are planned, and are detailed in Chapter 3 : • The District will continue moni toring to ensure the water quality requirements of the Lake Okeechobee Operating Permit are fulfilled. • Both the District’s monthly water quality monitoring program and its organics and pesticide monitoring progr am will be modified to focus resources on parameters that are know n to have potential sources in the watershed. • The applicability of additional mana gement strategies for canals and marinas will be determined.


### Reduction of In-Lake Nutrients

Due to an overabundance of nutrients inLake Okeechobee, a process known as eutrophication, large algal bloom s have periodically formed in Lake Okeechobee. Algal blooms are cause for concern becau se they may contain toxins th at affect fish and wildlife; they create taste and odor probl ems for drinking water; and wh en they die off and degrade, oxygen is removed from th e water column and wast e products (e.g., ammonia) accumulate, causing fish kills and the death of other aquatic life. Lake us ers also find these blooms unsightly, reducing their enjoyment of the resource. In-lake phosphorus must be reduced to a attain a more natural, lower frequency of potentially harmful algal blooms. To achieve this goal the SFWMD will do the following: • Evaluate the feasibility of re moving phosphorus-rich sediments from the lake • Evaluate the feasibility of chemi cal treatment of lake sediments to “inactivate” the phosphorus • Identify lake stage mana gement options that w ould facilitate greater coverage of submerged plants, and thus, greater phosphorus uptake • Complete research and model devel opment necessary to guide the most effective phosphorus reduction effort s, as called for in the Lake Okeechobee Protection Plan


### Environmental Resources Another goal of the Lake Okeechobee SWIM Program is to protect and enhance the lake’s environmental re sources. These resources in clude biological diversity, ecological functions, and the distribution and abundance of na tive plants and animals. The following objectives have been set to fulfill the environmental resource goal:vi Executive Summary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
• Identification of a range of water le vels that will al low for a healthy community of submerged and emergent native plants and the communities of fish and wi ldlife that they support • Identification and implementation of effective progr ams to control exotic plants, including melaleuca and torpedograss • Various in-lake habitat restoration projects carried out jointly with the Florida Fish and Wildlife Conservation Commission (FWC) Given the amount of public dollars that ar e being spent on the restoration of Lake Okeechobee, it is critical that we be able to track changes inthe health of the ecosystem both for 1) documentation of success, and 2) f eedback to managers so that, if necessary, management strategies can be modified. This “adaptive as sessment” strategy mirrors the approach being used in the CERP, and it includes long-term monitoring of a comprehensive set of ecological performance measures in the lake. These performance measures include submerged and emergent plants; plankt on and macro algae; benthic invertebrates; and fish. The pr ogram involves coordinated effo rts between the District and the FWC. Preserving and enhancing critical hab itats or areas to protect sensitive communities and/or rare, threatened, or endangered species is another of the environmental resource objecti ves for Lake Okeechobee. To fulfill this objective, the District will continue re storation evaluation effort s under the Kissimmee River Restoration Project and will coordinate with state and federal agenci es to complete the implementation of the South Florida Multispecies Recovery Plan in conjunction with the CERP

. The long-term goal, under the CERP, is to have hydrologic condi tions that include fewer extreme high water level events in the lake and fewer damaging discharges to the estuaries. In the interim, until the CERP is completed, we aim to minimize (to the extent possible with the existing sy stem) those impacts by careful use of the WSE schedule, including adaptive management protocols th at are driven by the needs of downstream systems for fresh and salt water. Those need s have been identified by an ongoing program of research, largely funded with SWIM dollars. 

### Flood Control and Water Supply The flood control and water supply goa ls for the Lake Okeechobee SWIM planning area are as follows: • Ensure adequate flood protection to local communities and agriculture around the lake • Provide a balance between the competing objectives of flood protection, water supply, and protection of the la ke’s marsh zone and downstream estuariesLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Executive Summary

vii • Maintain an adequate quantity of water in Lake Okeechobee to supplement downstream environm ental needs and reasonablebeneficial use requirements
The District will fulfill two objectives to ensure adequate flood protection for the Lake Okeechobee SWIM pl anning area. The first objective is to ensure design capacity of the Central and Southern Florida Project is met. The second objective is to continue reducing the Everglades Agricultural Area’ s dependency on the lake and the water conservation areas for flood cont rol. The District will also assist local governments in addressing flood protection in their comprehensive plans. As the local sponsor of the CERP a nd the Lake Okeechobee regulation schedule, the District must provide a balance between the competing objectives of flood protection, water supply, and protection of the lake ’ s marsh zone and downstream estuaries. To maximize the extent to which this balance is achieved prior to completion of the CERP, District and other agency scie ntists are working with operations specialists to identify environmental “triggers” that can be used in the process of the WSE regulation schedule for determining amounts of wa ter to release from the lake under flood control conditions. Information from the long-termecological assessment progr am, described above, will be supportive of this process, by providing information on ecologica l status of the lake at any given time. As noted, informat ion on declining lake health was a major driving force for the Lake Okeechobee Managed Recession Op eration in 2000. Results from ongoing experimental research with the lake's subm erged plant communities is also defining a “stage envelope” necessary to support this important resour ce, much like the “salinity envelope” that was recently developed for the St. Lucie Estuary to protect its biota. This information will be core to the scientific input in support of water release triggers under WSE.
The District must ensure Lake Okeechob ee has an adequate quantity of water to supplement downstream environmental, urban, and agricultural needs, and to recharge the coastal aquifer. To determin e the overall water supply dema nd that will be made on the lake, the urban and agricultu ral water supply needs must be updated regularly and the environmental water needs for the downstream e nvironment, as well as the role of Lake Okeechobee in meeting them, must be determin ed. Also, water supply demands need to be reduced. The District has developed and is implementing programs and projects that will reduce some of these demands including implem enting and improving the Lake Okeechobee Supply-Si de Management Plan (Hall, 1991).


### Recreation The District’s goal for recreation with in the Lake Okeechobee SWIM planning area is to attain recreational opportunities that meet public demand and are consistent with other SWIM goals. The District is achieving this goal by managing Lake Okeechobee in an effort to optimize opportuniti es for growth of native ve getation and enhance the health of the lake’s fisheries and associated recreational opportuni ties such as sport fishing, boating, ecotourism, and tournaments.viii Executive Summary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT 

### Navigation The Lake Okeechobee SWIM goals for navigation are to assist the USACE in maintaining navigability for commercial and recreational uses within Lake Okeechobee, the Lake Okeechobee Waterway, and recreational uses within the Kissimmee River. These goals are achieved by maintaining water storage in Lake Okeechobee, maintaining navigation locks and structures, and controlling aquatic weeds. With the restoration of the Kissimmee River under way, sp ecial consideration must be given to the changing navigation conditions th at are occurring on the river with the removal of structures and locks, and the resulting low water conditions.


### Public Involvement and Inte rgovernmental Coordination The public involvement and intergovernme ntal coordination goals for the Lake Okeechobee SWIM planning area are to prepare and impl ement an effective public awareness program and an effective intergovernmental awareness and involvement program. These programs will encourage public participa tion in the Lake Okeechobee SWIM planning process.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Table of Contents

ix 

## TABLE OF CONTENTS

Executive Summary i

List of Tables xi List of Figures xiii Acronyms and Abbreviations xvii Chapter 1: Introduc tion, Basin Descript ion, and Inventory 1
Introduction ..............................................................................................................1 Basin Description and Inventory .............................................................................9 Boundaries and Subbasins .....................................................................................13 Point and Nonpoint Poll ution Sources...................................................................15 Land Use ................................................................................................................18 

### Chapter 2: Watershed and Tributary Water Quality 21 Goals, Objectives, and Strategies ..........................................................................21 Phosphorus Loads and Targets by Basin ...............................................................24 Watershed Regulatory Programs ...........................................................................28 Comprehensive Everglades Restoration Plan ........................................................32 Current Management Programs .............................................................................33 Lake Okeechobee Protection Program and Permits ..............................................39 Class I, III, and IV Standards.................................................................................50 

### Chapter 3: In-Lak e Water Quality 67 Goals, Objectives, and Strategies ..........................................................................67 Nutrients .................................................................................................................69 Water Quality B udgets...........................................................................................77 Models ...................................................................................................................82 Sediment Assess ment ............................................................................................94 Class I Water Quality Parameters..........................................................................96x Table of Contents Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT


### Chapter 4: Environmental Resources 101 Goals, Objectives, and Strategies ........................................................................105 Ecological Impacts of Water Level Variation .....................................................107 Ecological Impacts of Nutrients ..........................................................................119 Ecological Impacts of Exotic Species..................................................................126 Long-Term Ecological Assessment .....................................................................128 Lake Okeechobee’s Role in th e Regional Ecosystem .........................................131 

### Chapter 5: Flood Contr ol and Water Supply 141 Goals, Objectives, and Strategies ........................................................................141 Flood Control.......................................................................................................144 Water Supply .......................................................................................................148 

### Chapter 6: Recreation 151 Goals, Objectives, and Strategies ........................................................................152 Recreational Activities.........................................................................................152 Summary of Recreat ion Issues ............................................................................155 Ongoing Activi ties...............................................................................................156 

### Chapter 7: Navigation 161 Goals, Objectives, and Strategies ........................................................................161 Navigation Lock Structures .................................................................................162 Summary of Naviga tion Issues ............................................................................163 

### Chapter 8: Public Invol vement and Intergovernm ental Coordination167 Goals, Objectives, and Strategies ........................................................................168 Review of Curren t Projects..................................................................................170 

### Chapter 9: Budget 173

References 183 Glossary 195Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT List of Tables

xi 

## LIST OF TABLES

Table 1-1. County census totals and the perc entage increase in the Lake Okeechobee SWIM planning area........................................................................................8 Table 1-2. Permits in the Lake Okeechobee planning area ............................................16 Table 1-3. Lake Okeechobee basi n land use summary...................................................17 Table 2-1. Phosphorus (P) loads and targets by basin in the Lake Okeechobee watershed for 1990-1994 ................................................................................................26 Table 2-2. Phosphorus (P) loads and targets by basin in the Lake Okeechobee watershed for 1995-2000 ................................................................................................27 Table 2-3. Works of the District per mits required for various land uses........................30 Table 2-4. The percentage of instances that Class I and III criteria was exceeded for tributary samples taken during infl ow periods to Lake Okeechobee a ...........53 Table 2-5. The percentage of in stances that the Class I, III, and IV criteria was exceeded for tributary samples taken duri ng periods of no inflow to Lake Okeechobee b ..................................................................................................56 Table 2-6. Results of fecal and total colifo rm measurements taken in lake okeechobee tributaries and in-lake stations from October 1993 to September 1994 cd .....63 Table 3-1. Water budget for Lake Okeechobee..............................................................78 Table 3-2. Lake Okeechobee phosphorus (P) budget in tons .........................................79 Table 3-3. Lake Okeechobee nitrogen (N) budget in tons..............................................81 Table 3-4. Percentage of instances that Clas s I criteria were exceeded within Lake Okeechobee a ..................................................................................................97 Table 4-1. List of the ecological performanc e measures associated with the Lake Okeechobee Conceptual Ecosystem Mode l, arranged according to the four major attributes............................................................................................131 Table 4-2. The federally-listed endangered and threatened species of South Florida..133 Table 6-1. Public recreation sites in the Lake Okeechobee SWIM planning area .......153 Table 7-1. Navigation lock structur es on the federal project........................................163xii List of Tables Lake Okeechobee SWIM Plan - June 21, 2002 DRAFTLake Okeechobee SWIM Plan - June 21, 2002 DRAFT List of Figures

xiii 

## LIST OF FIGURES

Figure 1-1. Review process for the La ke Okeechobee SWIM plan updates ....................3 Figure 1-2. Lake Okeechobee SWIM planning area.........................................................5 Figure 1-3. Land use within the Lake Okeechobee SWIM planning area......................19 Figure 2-1. Comparison of the modified Vollenweider model total phosphorus predictions to observed da ta for 1973 to 1979 .............................................24 Figure 2-2. The drainage basins that contribute nutrient enriched runoff to Lake Okeechobee ..................................................................................................25 Figure 2-3. The tributary stations samples were collected from to determine compliance with Class I, III, a nd IV Standards...............................................................51 Figure 3-1. Lake Okeechobee annua l average total phosphorus m ean of stations L001 to L008 .............................................................................................................69 Figure 3-2. Annual phosphorus loads to Lake Okeechobee ...........................................70 Figure 3-3. Phosphorus sediment concentrati ons (in parts per thousand) within Lake Okeechobee in 1988 and 1998 .....................................................................70 Figure 3-4. Yearly mean phosphor us versus lake stage at the nearshore and open water stations for 1986 to 2000..............................................................................71 Figure 3-5. Phosphorus water column con centrations in Lake Okeechobee during October and Nove mber 1999 .......................................................................72 Figure 3-6. Annual nitrogen loads to Lake Okeechobee ................................................73 Figure 3-7. Annual average nitrogen conc entrations in Lake Okeechobee ....................73 Figure 3-8. Average annual ratio of to tal phosphorus to total nitrogen..........................74 Figure 3-9. Average annual ratio of soluble nitrogen to phosphorus..............................74 Figure 3-10. Average annual chlorophyll a concentration in Lake Okeechobee..............75 Figure 3-11. Cumulative percent of chlorophyll a samples classified as a bloom condition (chlorophyll a > 40 ppb) at a) near shore stations and b) open water stations. .........................................................................................................76 Figure 3-12. Changes in total phosphorus (P) and dissolved reactive phosphorus (DRP) amounts at over 100 locations inLake Okeechobee between 1988 and 1998. ......................................................................................................80 Figure 3-13. Actual and target loads of phos phorus to Lake Okeechobee a) annually and b) as a five-year ro lling average...................................................................82 Figure 3-14. Five-year rolling aver age of a) tons of phosphorus above target and b) inflow to Lake Okeechobee.....................................................................................83 Figure 3-15. Five-year rolling average of phosphor us concentrations in inflows to Lake Okeechobee ..................................................................................................84xiv List of Figures Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
Figure 3-16. Comparison of the modified Vollenweider model total phosphorus predictions to observed da ta for 1973 to 2000 .............................................84 Figure 3-17. Comparison of a simple mass bala nce model total phosphorus predictions to observed data for 1973 to 2000....................................................................85 Figure 3-18. Comparison of total phosphorus pr edictions from a simple mass balance model, which includes a submerged aquatic vegetation component, to observed data for 1973 to 2000....................................................................86 Figure 4. A diagram of the Lake Okeechobee Water Quality Model..........................87 Figure 5. Simulations of the Lake Ok eechobee Water Quality Model under pre-1910 conditions to determine the maximum phosphorus inflow concentration that can be absorbed by the sedime nts without increasing phosphorus concentrations in the water column..............................................................88 Figure 6. Predictions of in-lake phosphor us concentrations under different inflow loads .............................................................................................................89 Figure 3-1. Lake Okeechobee hydrodynamic sedi ment transport mode l predictions of wave height on January 21, 2000.................................................................91 Figure 3-2. Lake Okeechobee hydrodynamic sedi ment transport mode l predictions of surface currents and sediment c oncentrations on January 21, 2000 ............92 Figure 3-3. Lake Okeechobee hydrodynamic sedi ment transport mode l predictions of bottom currents and sediment c oncentrations on January 21, 2000.............93 Figure 3-4. Locations within Lake Okeechobee where DDD p,p’ was detected in samples taken in 1998 ................................................................................................94 Figure 3-5. Locations within Lake Okeechobee where DDE p,p’ was detected in samples taken in 1998 ................................................................................................95 Figure 4-1. Hydrologic and morphological condi tions of Lake Okeechobee before human impacts (PAST), during the last 40 years (PRESENT), and anticipated when the CERP is completed (FUTURE) ...........................................................102 Figure 4-2. Maps of Lake Okeec hobee showing the area of litt oral zone that is inundated with water under a variety of lake stage elevations ...................................108 Figure 4-3. Areas of Lake Okeechobee th at support distinct primary producer assemblages, determined largely as a function of water depth ..................109 Figure 5. Four dominant vegetation communiti es in Lake Okeec hobee’s littoral zone based on 1996 aerial photographs ..............................................................110 Figure 4-1. Plot of monthly averaged wate r levels in Lake Okeechobee from 1973 to 2000............................................................................................................111 Figure 5. The spatial extent of bulrush along a 14-kilometer region of the littoral zone in 1992 versus 1999....................................................................................112 Figure 6. Results of a yearlyprogram (in this case the su mmer of 2000) that maps the distribution of submerged aquatic vegetation in Lake Okeechobee. .........113Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT List of Figures

xv Figure 7. Total amounts of biomass accrua l during a controlled experiment that exposed torpedograss to various water depths: a. biomass accrual for plant fragments attached to the sediment surface, and b. biomass accrual of established plants subjected to the same range of depth treatments ..........117 Figure 8. Total phosphorus concentrations measured during a controlled mesocosm experiment in the littoral zone af ter adding various amounts of phosphorus over a 28-day period...................................................................................122 Figure 9. A Conceptual model of alga l bloom dynamics in shallow eutrophic lakes............................................................................................................124 Figure 10. An ecosystem conceptual model for Lake Okeechobee, developed for the adaptive assessment proce ss of the CERP. ................................................130 Figure 5-1. The Run 25 Lake Oke echobee regulation schedule ...................................146 Figure 5-2. The WSE regul ation schedule....................................................................148 Figure 6-1. The Kissimmee River section of the Florida National Scenic Trail ..........157 Figure 6-2. The Lake Okeec hobee section of the Florida National Scenic Trail..........158 Figure 7-1. Navigation of the Kissimmee Ri ver during Phase I construction of the Kissimmee River Restor ation Project ........................................................165xvi List of Figures Lake Okeechobee SWIM Plan - June 21, 2002 DRAFTLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Acronyms and Abbreviations

xvii 

## ACRONYMS AND ABBREVIATIONS

o C degrees Celsius ASR aquifer storage and recovery BAT best available technologies BMP best management practice C&SF Central and Southern Florida CaCO 3 calcium carbonate CDS continuous deflective separation CERP Comprehensive Everglades Restoration Plan cfs cubic feet per second DDD, p,p’ dichlor diphenyl dichlor DDE, p,p’ dichlor diphenyl ethylene DDT dichlor diphenyl trichlor District South Florida Water Management District EAA Everglades Agricultural Area EAAMOD Everglades Agricultural Area Model EPD Everglades Protection District F.A.C. Florida Administrative Code FDACS Florida Department of Agricu lture and Consumer Services FDCA Florida Department of Community Affairs FDEP Florida Department of Environmental Protection FDOT Florida Department of Transportation FHANTM Field Hydrologic and Nutrient Transport Model FTA Florida Trail Association F.S. Florida Statutes FWC Florida Fish and Wildlife Conservation Commission GIS geographic information system ha hectare HIA high-intensity use area IFAS Institute of Food and Agricultural Sciences kg kilogramxviii Acronyms and Abbreviations Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

km kilometer LEC Lower East Coast LOADSS Lake Okeechobee Agricultural Decision Support System LOHSTM Lake Okeechobee Hydrodynamic a nd Sediment Transport Model LOPA Lake Okeechobee Protection Act MFL minimum flows and levels mgd million gallons per day mg/l milligrams per liter NGVD National Geodetic Vertical Datum NPDES National Pollution Discharge Elimination System NRCS Natural Resources Conservation Service PAM permit addendum modification PCA phosphorus control alternatives PLRG pollution load reduction goals ppb parts per billion ppm parts per million ppt parts per thousand RCRC Resource Conservation and Recovery Act Restudy Central and Southern Florida Pr oject Comprehensive Review Study SFWMD South Florida Water Management District SOR Save Our Rivers STA stormwater treatment area SWIM Surface Water Improvement and Management TMDL total maximum daily loads TST tributary sediment trap
μ g/l micrograms per liter USACE United States Army Corps of Engineers USEPA United States Environmental Protection Agency USFWS United States Fish and Wildlife Service USGS United States Geological Survey WCA water conservation area WMA wildlife management area WOD Works of the DistrictLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Acronyms and Abbreviations

xix WSE Water Supply and Environmentalxx Acronyms and Abbreviations Lake Okeechobee SWIM Plan - June 21, 2002 DRAFTLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Executive Summary

i 

## EXECUTIVE SUMMARY

This document provides an overview of the acti vities and accomplishments that have been directed towards the restorati on of Lake Okeechobee since adoption of the Surface Water Improvement and Manageme nt (SWIM) Plan - Update for Lake Okeechobee (SFWMD, 1997a). This update also describes th e current and proposed activities through 2000.
Lake Okeechobee and its watershed are key components of South Florida's Kissimmee-Okeechobee-Everglades ecosystem, wh ich extends from the headwaters of the Kissimmee River in the north to Florida Bay in the south. The lake provides a number of ecological and societal values. It is home to one of the nation's prized bass and speckled perch fisheries, as well as an economically important comm ercial fishery. At the same time, it provides habitat for a wide variety of wading birds, migratory waterfowl, and the federally-endangered Everglades Snail Kite. La ke Okeechobee is also a source of drinking water for cities and towns along the lake, and can be a backup water supply for the communities of the lowe r east coast of Florida. The lake also supplies irrigation water for the expansive Everglades Agricultural Area, and is a critical s upplemental water supply for the Everglades. The Lake Okeechobee SWIM pl anning area has been defi ned as the major basins that are direct tributaries to the lake, including those ba sins that are hydrologically upstream and/or from which wate r is presently released or pumped into the lake on a regular basis. Although the Lake Okeechobe e SWIM planning area generally excludes basins that are hydrologically downstream and act primarily as receiving basins for water supply (Caloosahatchee and St. Lucie River), the conveyance of flood control discharges and the resulting potential associated e nvironmental impacts ma ke these basins a component of this plan. The SWIM Act (Section 373.451-.459, Florida Statutes, [F.S.]), adopted by the Florida Legislature in 1987, requires water management districts, in conjunction with other state agencies and local governments, to prepare SWIM Plans for priority water bodies, including Lake Okeechobee. The SWIM Act requires that the plans describe strategies and potenti al programs for restoring or pr otecting the water body to Class III standards or better for r ecreation, propagation and mainte nance of a healthy, wellbalanced population of fish and wildlife. The plan must include a listing of studies that are being or have been prepared for the wate r body; a description of the research and feasibility studies that will be performed to determine the pa rticular strategy or strategies to restore or protect the water body; a descript ion of the measures needed to manage and maintain the water body once it has been restored and to pr event future de gradation; a schedule for restoration and pr otection of the water body; and an estimate of the funding needed to carry out the restor ation or protection strategies. The SWIM Act sets forth a specific pr ocess for the preparation, review, and approval of SWIM Plans. Itrequires the South Florida Water Management Districtii Executive Summary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
(SFWMD or District) to deve lop SWIM plans in cooperation with the Florida Department of Environmental Protection (FDEP) and other agencies. Pursuant to Section 373.455, F.S., the District submits a dr aft plan to the FDEP and othe r agencies. The FDEP reviews the cost of the SWIM Plan, funding availabi lity, and the likelihood that the plan will significantly improve or protect water quality and associ ated natural resources. If the FDEP determines that a SWIM plan does not meet minimum plan requirements, it shall recommend to the District modifications or additions to the planpursuant to Section 373.456(1), F.S. Other agencies review the plan for its effects on the resources within their respective jurisdictions and make recommendations. SWIM plans must be consistent with st ate water policy as outlined in Chapter 62-40, Florida Administrative Code (F.A.C), and to othe rwise provide guidance to the FDEP and the water management districts in the development and preparation of water management programs, rules, and plan s. Chapter 62-40.432 requires the water management districts to develop pollution lo ad reduction goals (PLRGs) for SWIM water bodies. The PLRG developed for Lake Okeechobee was a 40 pe rcent reduction in phosphorus loading from the watershed, based on the conditions thatexisted from 1973 to 1979 (Federico et al., 1981), withan expected dow nstream benefit of maintaining the trophic state and the biolog ical integrity of the lake. To as sist in achieving this goal, total phosphorus concentrations in runoff leavin g land parcels were limited by the Lake Okeechobee Works of the District (WOD) Rule. The total phosphorus concentration targets range from 0.18 to 1.2 milligrams per liter (mg/l). The federal Clean Water Act (Title 33, Chapter 26, Subchapter III, Section 1313(d)), requires that each st ate develop total maximum da ily loads (TMDLs) for each water-quality-limited segment reported. A TMDL reflects the total pollutant loading, from all contributing s ources, that a water segment can r eceive without excee ding its capacity to assimilate the pollutant loads and still meet applicable water qua lity standards. The phosphorus TMDL established fo r Lake Okeechobee is 140 metr ic tons (based on a 5-year rolling average) to achieve an in-lake ta rget phosphorus concentration of 40 parts per billion in the pelagic zone of the lake (FDEP 2000). The restoration target was determined using computer models deve loped based on past resear ch performed by the SFWMD using SWIM funds. This target will support a healthy lake system, restore the designated uses of Lake Okeechobee, and allow the lake to meet applicable water quality standards. The 1997 SWIM plan update reported that phosphorus load reductions had occurred, but the 40 percent reduction in loads was not ac hieved. It recommended the implementation of programs and projects to improve the la ke and watershe d water quality situation. The status of thes e programs and projects are summarized in this update. Even with the implementation of these programs and projec ts, nutrient loads to Lake Okeechobee have not decreased signifi cantly. The highest inflow phosphorus concentrations continue to be found in the S-154 and S- 191 basins where dairies are abundant and the majority of the out-o f-compliance WOD site s are found. Phosphorus loading is far in excess of the amount considered for a he althy Lake Okeechobee ecosystem and current model da ta predict that it may take decades before in-lake phosphorus concentrations will res pond to reduced external loads.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Executive Summary

iii Several major accomplishments have been ma de in the restoration effort since the publication of the last SWIM plan update in 1997. One of th e most important restoration actions was the Lake Okeechobee Managed Recession Operation. During six years prior to 2000, high water levels in the lake (associ ated with a prolonged wet period) destroyed nearly all of the lake’s subm erged plant beds and caused ex tremely poor water quality. The lake’s prize bass fishery wa s on the brink of ecological co llapse. A period of low water levels (less than 13 feet, lasti ng for at least 8 weeks) was requi red to allow recovery of the biological communities. In Ap ril and May 2000, approximatelyone foot of water was released from Lake Okeechobee. Coincident withthat, another one foot of water left the lake for normal water supply deli veries to agriculture and othe r uses, and one foot left the lake by direct evaporation into the atmosphere. Taken together the lake dropped by approximately 3 feet between April and July. As a result of the low water levels, Lake Okeechobee quickly recovered fr om its previously stress ed condition. Over 45,000 acres of new submerged plant beds grew during the summer and fa ll and the lake’s nearshore bulrush community (prime bass habitat) ex panded. The low water levels also allowed coordinating state and federal agen cies to carry out controlled fi res that have killed tens of thousands of acres of exotic plants that were taking over valuable wildlife habitat. A new regulation schedule for the lake was formally a dopted by the United States Army Corps of Engineers (USACE) in July 2000. This schedule, the Water Supply and Environment (WSE) schedule uses climate forecasting to dete rmine the volumes of water to release from the lake unde r flood control circumstances, and has the potential to provide environmental benefits for the lake and downstream systems while not sacrificing water supply. The extent of the benefits will depe nd in part on specific adaptive management protocols that are presently be ing developed by the District.
Restoration efforts for La ke Okeechobee were recently advanced with the passing of the Water Resources Developmen t Act of 2000 (WRDA 2000). The WRDA 2000 authorizes the Comprehensive Everglades Restoration Plan (CERP). The CERP is expected to have substa ntial effects on the lake's hydropatte rn. It is expect ed to reduce the number of extreme high and low events an d increase the occurrence of ecologically beneficial spring recession events. The act al so authorizes projec ts that will reduce nutrient loads to the lake. These components include regional stormwater treatment areas, reclamation of isolated wetlands, and regional water storage facilities, such as aquifer storage and recovery wells and reservoirs.
The enactment of the Lake Okeechobee Protection Ac t (LOPA) (Section 373.4595, F.S.) in 2000 also advanced restoration efforts. This act provides an umbrella that captures many lake restoration efforts. It will si gnificantly enhance mandates restoring and protecting the lake using a phased, wate rshed-based approach to reduce phosphorus loading to the lake and downstream receiving wate rs. Fulfilling this act will require a great deal of cooperation among governme nt agencies and the public. To facilitate the execution of the Lake Okeechobee Protection Plan, aninteragency committee was formed with individuals from the FDEP, the Florida Department of Agriculture and Consumer Services, and the SFWMD. The agencies are currently planning and implementing numerous management activitie s in the watershed to reduce phosphorus loading to the lake. These include the construction of surf ace water storage rese rvoirs and stormwateriv Executive Summary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

treatment areas; the restorati on of isolated wetlands the development and implementation of best management practices to control nonpoint sources of pollution; the continuation of research and monitoring to en sure the projects are designe d and implemented to optimize success; the removal of phosphorus-rich sedi ment from tributaries to Lake Okeechobee; and the implementation of a se diment management feasibilit y study to determine whether or not it is feasible to reduce internal lo ading from the lake se diments. More current information regarding the status of th e LOPA activities can be found in the Lake Okeechobee Protection Program A nnual Report to the Legislature (SFWMD, 2001a, 2001b). This update of the Lake Okeechobee SWIM Plan has set goals for the Lake Okeechobee SWIM planning area in the areas of water quality; environmental resources; flood protection and water suppl y; recreation, navigation, and public involvement; and intergovernmental coordination. Objectives have been deve loped to accomplish these goals. Programs and projects ar e being developed and will be implemented to achieve these objectives. The goals an d objectives, as well as some of the programs and projects are summarized below. 

### Phosphorus Load Reduction in the Tributaries In an effort to meet the propos ed TMDL target and in-lake phosphorus concentration of 40 parts per billion and ac hieve a phosphorus load of 140 tons per year, over-target phosphorus loading must cont inue to be reduced. The expanded WOD program, the new Lake Okeec hobee Protection Plan, and othe r new programs and projects are being implemented to achieve the inflow target are summarized in Chapter 2 and itemized below: • Best available technologies to significantly re duce the export of phosphorus from dairy operations into tributaries and Lake Okeechobee • Reservoir-assisted stor mwater treatment areas • Critical restoration projects • Isolated wetlands restoration • Natural resource economic analys is of a wide range of phosphorus control alternatives, using full-cost accounting practices • Sediment removal technolog ies in the tributaries • Research and modeling efforts to determine source of loads and methods to reduce themLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Executive Summary

v 

### Reduction of Nonnutrient Pollutant Loads To reduce the nonnutrient pollutant loads, Class I Water Quality Standards (potable water supplies) must be achieved within Lake Okeechobee and Cl ass III Water Quality Standards must be achieved within the lake tributaries. To achieve the in-lake reduction, the following initiatives are planned, and are detailed in Chapter 3 : • The District will continue moni toring to ensure the water quality requirements of the Lake Okeechobee Operating Permit are fulfilled. • Both the District’s monthly water quality monitoring program and its organics and pesticide monitoring progr am will be modified to focus resources on parameters that are know n to have potential sources in the watershed. • The applicability of additional mana gement strategies for canals and marinas will be determined.


### Reduction of In-Lake Nutrients

Due to an overabundance of nutrients inLake Okeechobee, a process known as eutrophication, large algal bloom s have periodically formed in Lake Okeechobee. Algal blooms are cause for concern becau se they may contain toxins th at affect fish and wildlife; they create taste and odor probl ems for drinking water; and wh en they die off and degrade, oxygen is removed from th e water column and wast e products (e.g., ammonia) accumulate, causing fish kills and the death of other aquatic life. Lake us ers also find these blooms unsightly, reducing their enjoyment of the resource. In-lake phosphorus must be reduced to a attain a more natural, lower frequency of potentially harmful algal blooms. To achieve this goal the SFWMD will do the following: • Evaluate the feasibility of re moving phosphorus-rich sediments from the lake • Evaluate the feasibility of chemi cal treatment of lake sediments to “inactivate” the phosphorus • Identify lake stage mana gement options that w ould facilitate greater coverage of submerged plants, and thus, greater phosphorus uptake • Complete research and model devel opment necessary to guide the most effective phosphorus reduction effort s, as called for in the Lake Okeechobee Protection Plan


### Environmental Resources Another goal of the Lake Okeechobee SWIM Program is to protect and enhance the lake’s environmental re sources. These resources in clude biological diversity, ecological functions, and the distribution and abundance of na tive plants and animals. The following objectives have been set to fulfill the environmental resource goal:vi Executive Summary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
• Identification of a range of water le vels that will al low for a healthy community of submerged and emergent native plants and the communities of fish and wi ldlife that they support • Identification and implementation of effective progr ams to control exotic plants, including melaleuca and torpedograss • Various in-lake habitat restoration projects carried out jointly with the Florida Fish and Wildlife Conservation Commission (FWC) Given the amount of public dollars that ar e being spent on the restoration of Lake Okeechobee, it is critical that we be able to track changes inthe health of the ecosystem both for 1) documentation of success, and 2) f eedback to managers so that, if necessary, management strategies can be modified. This “adaptive as sessment” strategy mirrors the approach being used in the CERP, and it includes long-term monitoring of a comprehensive set of ecological performance measures in the lake. These performance measures include submerged and emergent plants; plankt on and macro algae; benthic invertebrates; and fish. The pr ogram involves coordinated effo rts between the District and the FWC. Preserving and enhancing critical hab itats or areas to protect sensitive communities and/or rare, threatened, or endangered species is another of the environmental resource objecti ves for Lake Okeechobee. To fulfill this objective, the District will continue re storation evaluation effort s under the Kissimmee River Restoration Project and will coordinate with state and federal agenci es to complete the implementation of the South Florida Multispecies Recovery Plan in conjunction with the CERP

. The long-term goal, under the CERP, is to have hydrologic condi tions that include fewer extreme high water level events in the lake and fewer damaging discharges to the estuaries. In the interim, until the CERP is completed, we aim to minimize (to the extent possible with the existing sy stem) those impacts by careful use of the WSE schedule, including adaptive management protocols th at are driven by the needs of downstream systems for fresh and salt water. Those need s have been identified by an ongoing program of research, largely funded with SWIM dollars. 

### Flood Control and Water Supply The flood control and water supply goa ls for the Lake Okeechobee SWIM planning area are as follows: • Ensure adequate flood protection to local communities and agriculture around the lake • Provide a balance between the competing objectives of flood protection, water supply, and protection of the la ke’s marsh zone and downstream estuariesLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Executive Summary

vii • Maintain an adequate quantity of water in Lake Okeechobee to supplement downstream environm ental needs and reasonablebeneficial use requirements
The District will fulfill two objectives to ensure adequate flood protection for the Lake Okeechobee SWIM pl anning area. The first objective is to ensure design capacity of the Central and Southern Florida Project is met. The second objective is to continue reducing the Everglades Agricultural Area’ s dependency on the lake and the water conservation areas for flood cont rol. The District will also assist local governments in addressing flood protection in their comprehensive plans. As the local sponsor of the CERP a nd the Lake Okeechobee regulation schedule, the District must provide a balance between the competing objectives of flood protection, water supply, and protection of the lake ’ s marsh zone and downstream estuaries. To maximize the extent to which this balance is achieved prior to completion of the CERP, District and other agency scie ntists are working with operations specialists to identify environmental “triggers” that can be used in the process of the WSE regulation schedule for determining amounts of wa ter to release from the lake under flood control conditions. Information from the long-termecological assessment progr am, described above, will be supportive of this process, by providing information on ecologica l status of the lake at any given time. As noted, informat ion on declining lake health was a major driving force for the Lake Okeechobee Managed Recession Op eration in 2000. Results from ongoing experimental research with the lake's subm erged plant communities is also defining a “stage envelope” necessary to support this important resour ce, much like the “salinity envelope” that was recently developed for the St. Lucie Estuary to protect its biota. This information will be core to the scientific input in support of water release triggers under WSE.
The District must ensure Lake Okeechob ee has an adequate quantity of water to supplement downstream environmental, urban, and agricultural needs, and to recharge the coastal aquifer. To determin e the overall water supply dema nd that will be made on the lake, the urban and agricultu ral water supply needs must be updated regularly and the environmental water needs for the downstream e nvironment, as well as the role of Lake Okeechobee in meeting them, must be determin ed. Also, water supply demands need to be reduced. The District has developed and is implementing programs and projects that will reduce some of these demands including implem enting and improving the Lake Okeechobee Supply-Si de Management Plan (Hall, 1991).


### Recreation The District’s goal for recreation with in the Lake Okeechobee SWIM planning area is to attain recreational opportunities that meet public demand and are consistent with other SWIM goals. The District is achieving this goal by managing Lake Okeechobee in an effort to optimize opportuniti es for growth of native ve getation and enhance the health of the lake’s fisheries and associated recreational opportuni ties such as sport fishing, boating, ecotourism, and tournaments.viii Executive Summary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT 

### Navigation The Lake Okeechobee SWIM goals for navigation are to assist the USACE in maintaining navigability for commercial and recreational uses within Lake Okeechobee, the Lake Okeechobee Waterway, and recreational uses within the Kissimmee River. These goals are achieved by maintaining water storage in Lake Okeechobee, maintaining navigation locks and structures, and controlling aquatic weeds. With the restoration of the Kissimmee River under way, sp ecial consideration must be given to the changing navigation conditions th at are occurring on the river with the removal of structures and locks, and the resulting low water conditions.


### Public Involvement and Inte rgovernmental Coordination The public involvement and intergovernme ntal coordination goals for the Lake Okeechobee SWIM planning area are to prepare and impl ement an effective public awareness program and an effective intergovernmental awareness and involvement program. These programs will encourage public participa tion in the Lake Okeechobee SWIM planning process.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

1 

## Chapter 1 INTRODUCTION, BASIN DESCRIPTION, AND INVENTORY

A. INTRODUCTION
This update provides an ove rview of the activities and accomplishments achieved since adoption of the Surface Water Improvement and M anagement (SWIM) Plan - Update for Lake Okeechobee (SFWMD, 1997a) on August 8, 1997. Th e highlights of any projects completed since the 1997 SWIM plan update are provided, as well as current and proposed activities for th e short- and long-term. The structure of this plan includes the issues, goals, obj ectives, and strategies that provide the framework around which the S outh Florida Water Management District (SFWMD or District) initiates or conti nues programs to protect the lake. The goals provide the general direction for developi ng cohesive manageme nt strategies, the objectives describe more specif ic approaches towards achieving a particular goal, and the strategies provide the detail needed to accomp lish an objective. For each strategy, progress and projects are being devel oped and implemented. Each chap ter is developed with three components: 1) the issues and the strategies developed to address these issues; 2) the present condition as it exists in the waters hed or the lake; and 3) a summary of the progress to date on each program or project. 

### A1. SWIM Plan Requirements and Planning Process A1a. Plan Requirements The SWIM Act (Section 373.451-.459, Florida Statutes [F.S.]) was adopted by the Florida Legislature in 1987. This law requi res that water manage ment districts, in conjunction with other state agencies and local governments, prepare SWIM plans for priority water bodies as identified by the SWIM Act. The 1987 legi slation required the District to develop plans for Lake Okeechobee, the Indi an River Lagoon, and Biscayne Bay. The SWIM Act required that the plan s demonstrate strategi es and programs to address the following central concerns: • Point and nonpoint source pollution (Section 373.451(4)(a), Florida Statutes [F.S.]) • Destruction of natural systems (Section 373.451(4)(b), F.S.) • Correction and prevention of surface water problems (Section 373.451(5), F.S.) • Research for better management of surface waters and associated natural systems (Section 373.451(7), F.S.)2 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
SWIM legislation also specifies the mi nimum requirements for the plans contents (Section 373.453(2) F.S.). These re quirements are described in the Surface Water Improvement and Management Review Procedures Manual (FDER, 1990). The required descriptions of the water body, point and nonpoint sources of pollution, land uses, and agency jurisdictions ar e provided later in this chapter and in the appendices. The remaining requirements that describe strategies for restoring and protecting water quality, includi ng the current condition and futu re plans for restoring the water body, are presented within the individual plan chapters ( Chapters 2 through 8 ). The Florida Department of Environmental Protection (FDE P) is required by Section 373.456, F.S., to review ea ch SWIM plan for consistency with state water policy as outlined in Chapter 62-40, Florida Administrative Code (F.A.C). Chapter 62-40 is intended to clarify state wate r policy as expressed in Chapters 187, 373, and 403, F.S., and to otherwise provide guidance to the FDEP and the water management districts in the development and preparation of water management programs, rules, and plans. The intent of Chapter 62-40 is as follows: “The waters of the state are am ong its basic resources. Such waters should be manage d to conserve and protect natural resources and scenic beauty and to realize the full beneficial use of the resource. ” Therefore, Chapter 62-40 provides the basis for the FDEP's review of all water management di strict SWIM planning documents with respect to me eting state water policy require ments. SWIM legislation is provided in Appendix A of this plan. Chapter 62-40.432 requires the water manage ment districts to develop pollution load reduction goals (PLRGs) for SWIM wa ter bodies. PLRGs are defined as targeted reductions in pollutant loadi ngs to a water body n eeded to achieve watershed management goals. Watershed management goals are defined as the goals that enco mpass any one or all of the major water management district re sponsibilities: flood pr otection, water supply, water quality, and environmental system pr otection and enhancemen t. The goals provide the general direction for developing cohesive strategies to manage water resources within a drainage basin, subbasin, or segment of a drainage basin or subbasin. The PLRG developed for Lake Oke echobee is a 40 percent reduction in phosphorus loading from the watershed, based on the conditions thatexisted from 1973 to 1979 (Federico et al., 1981). This percent reduction was expected to maintain the trophic state and the biological integrity of the lake. Early reports clearly indicated that phosphorus was a major contributor to accel erated eutrophication of Lake Okeechobee (Davis and Marshall, 1975; Federico et al., 1981; Joyner, 1972; Kissimmee-Okeechobee Basin Report, 1972). Eutrophication was and remain s a clear threat to the health of this lake, and is the focus of the majority of pr ojects designed to impr ove the condition of the lake. Progress towards achievi ng the PLRG is evaluated by comparing a target five-year rolling average of phosphorus loading to the lake , as specified in Federico et al. (1981) to the actual calculated loading from the discharge structures. In 2001, a phosphorus total maximum daily load (TMDL) of 140 tons per year was established for the lake in an effort to achieve the in-lake phosphorus conc entration of 40 micrograms per liter ( μ g/l) (described in more detail in Chapters 2 and 3 ). The TMDL is more stringent than theLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

3 PLRG developed in 1981 (Federic o et al., 1981), and it incorpor ates the recognition of the capacity of the lake to cont inue to assimilate phosphorus. A1b. Review and Approval Process The SWIM Act sets forth a specific pr ocess for the preparation, review, and approval of SWIM Plans ( Figures 1-1 ). It requires the District to develop SWIM plans in cooperation with the FDEP and other agencies . The review process is initiated when the District submits the dr aft plan to the FDEP and other agencies for a 45-day agency review period (Section 373.455, F.S.). Othe r agencies review the pl an for its effects on the resources within their respective jurisdicti ons and make recomme ndations. These agencies include the FDEP, the Florida Department of Agriculture a nd Consumer Services (FDACS), the Florida Departme nt of Community Affairs (FDCA), Florida Fish and Wildlife Conservation Service (FWC), and local governments. After the 45- day review period, the District has 15 days to prepare a response and pres ent the agencies positions to the Governing Board of the District.

Review criteria include cost, funding avai lability, and the likelihood that the plan will significantly improve or pr otect water quality and associated natural resources. If the FDEP determines that a SWIM plan does notmeet minimum plan requirements, the FDEP shall recommend to the District modifications or additions to the plan pursuant to Section 373.456(1), F.S.
The first draft of the 2002 Lake Okeechobee SWIM Plan Update was presented to the District's Governing Board on _________, 2002. At this meeting, the Governing Board was presented an overview of the plan and gave approval to initiate the public participation process. On ________ and ___________, public meetings were held in Public Meetings Okeechobee

Clewiston Governing Board Workshop Discuss First Draft of Plan Final Draft Submitted for 373.455, F.S., Review (45 Days) FDEP, FDACS, FDCA, FWC, Local Governments

SFWMD Review of Agency Comments

Final Draft Approved by SFWMD Governing Board Final Draft SWIM Plan Adopted by SFWMD

Governing Board A pproved Final Draft 373.456, F.S., Consistency Review (30 days)

Figure 1-1. Review process for the Lake Okeechobee SWIM plan updates4 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
Okeechobee and Clewiston, respectively, to disc uss the update. Commen ts received as a result of these meetings ar e assembled in the appendices. A final draft was approved by th e Governing Board on ___________. The plan was then transmitted to the FD EP to ensure consistency with the State Water Policy and the State Comprehensive Plan, pursuant to Section 373.456, F.S. The FDEP found the plan update consistent with the St ate Water Policy (Chapter 62-40, F.A.C.) and the State Comprehens ive Plan (Chapter 187, F.S.) on ___________. The approved plan became effectiv e on _________, with public notice in the Florida Administrative Weekly

. 

### A2. Relationship to Other Planning Efforts Lake Okeechobee is a key component ofSouth Florida's Kissimmee-OkeechobeeEverglades surface water hydrol ogic and ecological system. The system begins in Central Florida near Orlando, extends southward through the Kissim mee Chain of Lakes, the Kissimmee River, Lake Okeechobee, and continues southward through the Everglades into Florida Bay. In addition, through man-ma de canals, Lake Okeechobee is connected to the St. Lucie and Caloosahatchee estuaries. The SWIM Act Prio rity Water Body List identified one portion of this system, Lake Okeechobee, as an area of immediate high priority. The District realized that this piece of the Kissimmee-Okeechobee-Everglades system could not be looked at in isolation from the rest of the system, but did not believe that the planning and research re sources of the District were ad equate to address this entire system within a single SWIM plan. The Kissimm ee-Okeechobee-Evergl ades area was divided, based on hydrologic feat ures, into SWIM planning areas. Boundaries of SWIM planni ng areas were determined by taking the receiving water body (in this case Lake Okeechobee) and including the tributary basins that deliver water into the lake. Thus, the Lake Okeechobee SWIM planning area ( Figure 1-2 ) includes such major inflow ba sins as the Kissimmee River, canals downstream from Lake Istokpoga, Fisheating Creek, vari ous basins that pump water directly into the lake for routine drainage purposes, the St. Luci e Canal, and the Taylor Creek/Nubbin Slough basin.
The basin boundaries of the Lake Okeec hobee SWIM planning area overlap with those of the Everglades Prot ection Area and the Indian Ri ver Lagoon. This overlap occurs for a variety of reas ons, primarily because Lake Okeechobee is a major source of inflow water for the Everglades region and, when the C-44 Canal is below 14.5 feet, for the Indian River Lagoon. Water use demands and flood protection requirements within the Everglades influence water suppl y, water quality, and lake wa ter level issues within the Lake Okeechobee SWIM planning area. This plan update includes descriptions of two projects as sociated with the Everglades Forever Act. The first projec t required the Chapter 298 Special Drainage Districts discharging into Lake Okeechobee to complete c onveyance system modificationsLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

5 Figure 1-2. Lake Okeechobee SWIM planning area6 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
sufficient to redirect 80 percent of their runof f to the District's primary canal system for subsequent treatment in st ormwater treatment areas (S TAs) (Section 373.4592(4)(a)8, F.S.). The second project requi red the FDEP and the SFWMD to request the United States Army Corps of Engineers (U SACE) to evaluate Lake Okeechobee regulatory releases (Section 373.4592(4)(b)4, F.S.). This evaluation resulted in the adoption of the Water Supply and Environmental (WSE ) regulation schedule. This schedule facilitates the releases of water into the Ev erglades Protection Area in order to further improve lake hydroperiod restoration and redu ce harmful discharges to the estuaries and wasteful discharges to tide. It is critical to the SWIM process that th e related plans are cons istent and that these plans be coordinated with other SWIM pl anning efforts currently under way in South Florida (e.g., Indian River Lagoon and Biscayne Bay SWIM Plans, Kissimmee River Restoration, regional water supply pl ans, and the Everglades Program). 

### A3. Agency Jurisdictions and Institutional Authorizations
A3a. Federal Federal jurisdiction of Lake Okeechobee involves the regulatory responsibilities of the USACE, the United States Environmen tal Protection Agency(USEPA), and the United States Fish and Wildlife Servi ce (USFWS). The USACE is responsible for prescribing the operational crit eria and regulation schedules for the Central and Southern Florida (C&SF) Project. Its primary re gulatory functions include operation and maintenance of the levee and major outlet wo rks, dredge and fill permitting, maintaining navigable United States waters, cleanup of pollution spills, and the protection of endangered species. The USEPA is responsib le for protection of the environmental resources of Lake Okeechob ee. The USEPA has oversight responsibility for Florida’s National Pollutant Di scharge Elimination System (N PDES) and Resource Conservation and Recovery Act (RCRC) (als o known as the Solid Waste Di sposal Act). The USFWS is responsible for conserving, protecting, and enha ncing fish and wildlife communities and their habitats in Lake Okeechobee. Several other federal agencies also contribute to management and data collection in Lake Okeechobee. These include the United States Geological Survey (USGS), the United Stat es Forest Service, the National Weather Service, the United States Department of Agri culture, and the Department of the Interior. A3b. Comprehensive Evergl ades Restoration Plan
The USACE and the SFWMD conducted a feas ibility review of the C&SF Project and presented their recommendations in the Central and Southern Florida Project Comprehensive Review Study, Final Integrated Feasibility Report and Programmatic Environmental Impact Statement (USACE and SFWMD, 1 999). These recommendations will be implemented through the Comprehensive Everglades Restoration Plan (CERP). The primary purpose of the CE RP is the restoration of South Florida’s ecosystem including the Everglades. It also provides for the other water-related needs of the region including urban and agricultural water supply and flood protection. The CERP willLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

7 accomplish this by storing most of the water currently disc harged to the ocean, improving the quality of water discharged into the ecosystem, and removing over 240 miles of internal levees in the Everglades. Most CERP projects will be implemented by 2020, but several will not be completed until 2050. The basic approach of CERP is to captur e most of the 1.7 billion gallons of water per day that on average flows to the ocean. The water will be st ored in surface and underground storage areas until it is needed to supply the natural system as well as urban and agricultural needs. The ti ming and distribution of water fl ows to the ecosystem will be modified to more closely approximate predra inage patterns. Wetlands-based STAs will be built to improve quality disc harges to the natural system . Seepage management will be initiated to reduce unwanted water loss. Wastewater will be reclaimed and reused. Flows will be redirected westward to the Wa ter Conservation Areas (WCAs), Everglades National Park, and northeasternShark River Slough. The three features to reduce seepage are 1) addition of impervious barriers to the le vees to block loss of wa ter; 2) installation of pumps near levees to redirect water back into the Everglades; and 3) hold water levels higher in undeveloped areas between the Everglades and Palm Beach, Broward, and Miami-Dade counties. Operati onal changes in water delivery schedules will be made in some areas to alleviate extr eme fluctuations. Lake Okeec hobee water levels are being modified to improve the health of the lake . In other areas, a rain fall-driven operational plan will enhance the timing of water flows ( Chapter 5 ).
A3c. State Many state agencies are i nvolved with both the mana gement and regulation of activities in Lake Okeechobee. The FDEP and the FWC are le ading state agencies in the protection and management of the lake. Their jurisdictions include the protection of water quality, wetland resources , fisheries, and wildlife res ources of Lake Okeechobee. The FDEP issues National Pollutan t Discharge Elimination Syst em permits for point source discharges. Other state agencies that have a role in managing the lake include the Florida Department of Health and Re habilitative Service, the FDCA , the FDACS, and the Florida Department of Transportation (FDOT). The SFWMD’s Water Resource Advisory Committee, a multiagency/multiuser group, also provides input to is sues associated with the lake and its watershed. A3d. Regional At the regional level, the SFWMD and four regional pl anning councils have jurisdiction within the Lake Okeechobee SWIM planning area. The District’s authority is to manage and protect the wa ter resources in a 16-county re gion that includes the Lake Okeechobee SWIM planning area. Regional planning council jurisdictions are assigned by county. Palm Beach, St. Lucie, Indian River, and Martin counties are within the Treasure Coast Regional Planning Council. The Southwest Florida Regi onal Planning Council has jurisdiction within Glades and Hendry counties. The Cent ral Florida Regional Planning Council has jurisdiction within Okeechobee and Highlands counties. The East Central Florida Regional Planning Council has jurisd iction within Polk and Osceola counties. Regional planning councils have responsibilities to deve lop regional comprehensive8 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
policy plans for protection of water res ources within the Lake Okeechobee SWIM planning area, provide assist ance to local governments on related issues, and determine impacts of proposed developm ent on the lake and other re lated resources. The regional planning councils have all a dopted regional policy plans that include goals and policies designed to aid in the protect ion of all surface and ground waters in the region, including Lake Okeechobee and its tributaries. Th e regional planning councils also provide technical assistance to local governments and evaluate anticipated impacts from Developments of Regional Impact on regi onal resources, such as Lake Okeechobee.
A3e. Local The local governments have the authority to control land use in the Lake Okeechobee watershed through their compre hensive plans and land development regulations. They also have authority to regulate water qual ity and nuisances. Sectors that exist at the local government level include planning, building, z oning, and regulatory departments; water and sewer utilities; city and police department s; and soil and water conservation districts. The various count ies and municipalities have developed comprehensive plans that guide the future development and pr eservation of local resources. Recent (2000) cens us figures are provided in Table 1-1

.



### A4. Goals The goals for each part of this update are summarized below:

• Water Quality- Reduce pollutant loads fr om the watershed and reduce in-lake nutrients that stimulate al gal blooms and ensure that the lake can support and sustain a healthy, natural ecosystem Table 1-1. County census totals and the percentage increase in the Lake Okeechobee SWIM planning area

County 2000 Population Percent Increase (since 1997 SWIM Plan update) Hendry 36,210 22 Highlands 87,366 15 Glades 10,576 38 Martin 126,731 12 Okeechobee 35,910 16 Osceola 172,493 24 Palm Beach 1,131,184 14 Polk 483,924 10 St. Lucie 192,695 10Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

9 • Environmental Resources - Protect and enhan ce the environmental resources of Lake Okeechobee, and enhance the lake's functional role in the regional aquatic ecosystem

• Water Supply/Flood Protection - Maintain an ad equate quantity and quality of water in Lake Okeechobee to supplement downstream environmental needs and to meet reasonable and beneficial use requirements while ensuring adequate flood protection to local communities and agriculture around the lake

• Recreation - Attain recreational opportuni ties that meet public demand and are consistent w ith other SWIM goals

• Navigation - Assist in maintaining navi gability within the federallyoperated navigation projects in the Lake Okeechobee planning area (Kissimmee River and Okeec hobee Waterway, including the Caloosahatchee River and the St. Lucie Canal)

• Public Involvement and Inter governmental Coordination - Prepare and implement effective public a nd intergovernmental awareness programs and encourage public participation in the Lake Okeechobee SWIM planning process


## B. BASIN DESCRIPTION AND INVENTORY

Lake Okeechobee and its watershed are key components of South Florida's Kissimmee-Okeechobee-Everglades ecosystem, wh ich extends from the headwaters of the Kissimmee River in the north to Florida Bay in the south. The lake is the second largest freshwater body located wholly within the continental United States. It provides a number of ecological and societal values. It is home to one of the nation's prized bass and speckled perch fisheries, as well as an economically important comm ercial fishery. At the same time, it provides habitat for a wide variety of wading birds, migratory waterfowl, and the federally-endangered Everglades Snail Kite. La ke Okeechobee also is a source of drinking water for lakeside cities and towns, and ca n be a backup water supply for the communities of the lower east coast of Florida. The lake also supplies irrigation water for the expansive Everglades Agricultural Area (EAA), and is a critical supplementa l water supply for the Everglades. Given these often- competing demands on the lake , management of the water resource is a major challenge. 

### B1. History Geological survey data indicate that Lake Okeechobee wa s formed about 6,000 years ago, when ocean waters receded and water was left st anding in a shallow depression in what today is known as the State of Florida (Gleason and Stone, 1975). The original lake probably was saline (salty), but over time the salt water was replaced by fresh water from rainfall. The expansive la ke that resulted from this process was named Okeechobee, which means “big water” in the Seminole Tr ibe language. The lake had a large littoral (wetland) zone that extended from the Kissimmee River to the Florida Everglades, and a10 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
pelagic (open water) zone that was much larger and probably as much as 3 feet deeper than that observed today. During periods of hi gh rainfall, the littoral zone expanded far to the west, and the lake was a di rect source of water to th e Everglades by way of broad sheetflow and blind stream ch annels passing out of the lake’s southern end. Results of sediment surveys, including pa leolimnological (past lake hist ory) analyses indicate that sediments of the lake were primarily comprised of sand. The nearshore regions of the lake probably supported dense beds of submerged plants and nest ing and feeding habitat for fish and wildlife (Steinman, 2001). 

### B2. Human Impacts The following major issues have been identi fied as most critical for restoration of the Lake Okeechobee ecosystem: • External loads of phosphorus to the la ke must be substantially reduced. • Internal loading of phosphorus from the lake sediments must also be reduced, if feasible, or responses to external load reduction will be considerably delayed. • Extremely high and low water levels must be dramatically reduced in their frequency and duration. • The rapid expansion of exotic plants in the lake’s littoral zone must be stopped. B2a. Excessive Nutrient Inputs During the Twentieth Century, much of the land around La ke Okeechobee was converted to agricultural use. To the north, dairy farms and beef cattle ranching became the major land uses, while to the south, sugarcane and vegetable farming increased rapidly. These land use changes resulted in a large increase in the rate of nutrient (nitrogen and phosphorus) inputs to the la ke, and detrimental changes oc curred in the lake’s water quality. Nitrogen inputs were particularly high from the s outh. These nitrogen inputs were significantly reduced after the late 1970s when an inte rim action plan (SFWMD 1979) prohibited pumping of agricultural water in to the lake from th e south except under situations where farmlands would otherwise be flooded. Phosphorus inputs from the northern watershed increased dr amatically, and can be traced primarily to the animal agricultural activities in that watershed. Loads (concentration times flow) of total phosphorus to the open water region of the lake nearly tripled betweenthe early 1970s and mid-1980s, and coincident with this trend, the concentration of phosphorus in the lake itself increased from below 40 to over 100 parts per billion (ppb). Blooms of blue-green algae became more common, wi th particularly large bloom s covering more than 40 percent of the lake surface in the 1980s. A number of pr ograms have been implemented and others are under devel opment to substantially re duce phosphorus loads to Lake Okeechobee (Havens et al., 1996a). During the early 1990s, scientis ts discovered that one of the greatest challenges in reversing harmful trends caused by excessive phosphorus may be in controlling sourcesLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

11 internal to the lake. Becaus e high phosphorus loads have occu rred for over 60 years, more than 30,000 tons of phosphorus has accumulated at the bottom of the lake, in the form of soft organic mud (Olila and Reddy, 1993; Stei nman et al., 1999). Be cause of the lake's shallow depth (averaging just 2.3 meters or 9.0 feet), this mud is mixed into the water column every time strong winds blow across the lake’s surface. This keeps the phosphorus concentration in the water column high. When the turb id water (water clouded by sediments from the lake botto m) is transported to the nearshore region, it prevents submerged plant beds from gett ing the light they need to grow. Phosphorus in the water also may stimulate the grow th of cattails al ong the edge of the littoral zone. Because so much phosphorus is being stored within th e lake's sediment, internal loads of phosphorus (from sedime nt to water) now equal exte rnal loads (coming from the watershed to the lake). Given this condition, the lake's recove ry will be severely delayed. Even when external loads are dramaticallyreduced, the lake's sediments act as a phosphorus reservoir and conti nue to release phosphorous into the water column of the lake. Some combination of se diment removal and external load reduction may be needed to achieve recovery of Lake Okeechobee in a relatively short (decades) time frame. B2b. Hydrologic Modifications Other changes in South Florida have ha d severe impacts on Lake Okeechobee. In the 1890s, Hamilton Disston cons tructed a canal connecting Lake Okeechobee with Lake Hicpochee, the headwaters of the Caloosahat chee River. This provided the lake’s first outlet to tidewater via the Caloosahatchee River. In the early 1900s, the Everglades Drainage District constructe d several other canals that impacted Lake Okeechobee. The St. Lucie, Hillsboro, North New River, West Palm Beach, and Miami canals were constructed to deliver water fr om the lake to tide. These canals provided slow, continuous drainage from Lake Okeechobe e and the Everglades. The goa l was to drain the northern Everglades for agriculture.
Small towns arose in this re gion, some very close to th e lake. A small muck levee was constructed along the southernshore of the lake to prot ect those towns and farms. In the 1920s, two major hurricanes struck South Florida. One of them generated a storm surge in the lake that flooded coastal areas and hundreds of acres to the south and killed approximately two thousand people. To prevent this kind of devast ation from recurring, the state asked the United States Congres s for help. In 1931, Cong ress directed the USACE to lead efforts to prevent future tragedie s of that scale. One of the first features the USACE constructed was the He rbert Hoover Dike, an earthe n levee that consisted of sections along the north and sout h shoreline. This was the firs t project for flood protection in Florida by the USACE. One of the major impacts of the dike on Lake Okeechobee was to restrict the littoral z one to a much smaller region, along the western and southern shorelines. When water levels in the lake beco me very high, this reduced littoral zone can no longer expand outward. Instead, it is fl ooded with deeper and deeper water. In 1948, Congress authorized the USACE to implemen t a comprehensive water resources project, the Centra l and Southern Florida Projec t for Flood Control and other purposes. This project is now re ferred to as the C&SF Project. As a result of the system of12 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
canals and levees built by the USACE, all discharges into (except Fisheating Creek) and out of the lake are now artificially controlled. The 1948 authorization required that th e SFWMD operate and maintain all components of the C&SF Project, except the main outlets of Lake Okeechobee and the WCAs, in accordance with rules prescribed by the Secretary of the Army. As a result, the USACE establishes the regulation schedul e for Lake Okeechobee that defines the operating rules required to meet the authori zed project purposes. Th e regulation schedule was designed to provide floodwater stor age capacity during th e wet season, and to supplement water supply during the dry season. Because of recen t increases in rainfall, the lake has experienced frequent and prolonged hi gh water levels that have been extremely damaging to both the lake and to downstream ecosystems. These high water levels led to drastic declines in the lake's submerged plant beds. Also, scientists at the FWC have recently suggested that juvenile age classes of important s port fish (such as bass) have substantially declined (FWC unpublished data). When lake levels were particularly hi gh, large flood control discharges of fresh water are sent through canals to the St. Luci e and Caloosahatchee estuaries, where they had severe impacts on estuar ine organisms. A new lake regulation schedule, the WSE schedule, that will attempt to reduce the oc currence of extreme high water events by using climate forecasting, was implemented in Ju ly 2000, and is discussed in detail in Chapter 5

. Extremely low water levels during the dry season can thr eaten the lake's ecological health by allowing certain exotic plants that have invaded the litto ral zone to rapidly expand. Alternatively, low lake levels can faci litate exotic control programs, such as fire and herbicide treatments that occurred during the 2000 manage d recession. Low water levels may become a greater co ncern in the future when a greater water supply is needed for both Everglades restoration and the gr owing human population of South Florida.
B2c. Exotic Plants and Animals A large percentage of the na tive plant habitat in the la ke’s littoral zone (about 20 percent or over 20,000 acres) has be en overtaken by exotic plan ts, most notably melaleuca and torpedograss. Melaleuca is a native tree of Australia and torpedograss is a pasture grass native to Europe. Both we re planted intentionally in the vicinity of the lake, and both rapidly colonized the littoral zone. The SFWMD and other ag encies are actively engaged in a program to eradicate melaleuca from S outh Florida using herbicide and biological control agents. The spread of melaleuca and torpedograss has been documented to be increased by low lake stage. Work is in progr ess to better quantify this linkage, which is critical to the development of lake operati ng protocol under CERP as well as to the success of ongoing exotic control efforts. District scientists identified an improved control program for torpedograss in the late 1990s and it was implemented in 2000-2001. Widespread control is expected to take many years. The lake also contains exotic animals, including an asiatic clam and fish, but th eir negative impacts have not been well documented.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

13 

## C. BOUNDARIES AND SUBBASINS
The Lake Okeechobee SWIM planning area ( Figure 1-2 ) has been defined as the major basins that are direct tributaries to the lake, including those basins that are hydrologically upstream and/ or from which water is presently released or pumped into the lake on a regular basis. Wate r from several tributaries drai ns into the lake through the Kissimmee River (C-38), incl uding the S-65 series of basi ns, the S-84 basin, and the S-154 basin. The S-133 basin al so drains into the lake from the north. The Taylor Creek\Nubbin Slough basin and th e S-135 drain into the lake from the northeast. The following basins drain into the lake from the northwest: Arbuckle Creek, Istokpoga, C-41, S-65E, C-40, S-84, L-48, L-49, and S-131. Wate r from the S-135 and C-44 basins drain into the lake through the St. Lucie Canal when lake stage permits. Ba sins that drain from the EAA into the lake include the S-4 and Chapter 298 Special Drainage Districts, and Agricultural Lease #3420. The Chapter 298 Speci al Drainage Distri cts include the East Beach Water Control District, the East Shore Drainage District, th e South Shore Drainage District, the Industrial Canal, the South Florida Conservancy (S-236), and 715 Farms. Additionally, water from th e S-2 and S-3 basins is backpumped into the lake during flood or emergency water conditions. Th e Fisheating Creek basi n drains into the lake from the western shore wh ile the East Caloosahatchee ba sin drains into the lake from the west only during extreme c onditions (i.e., when the lake level drops to 11.5 feet). A detailed discussion of these basins, including their associated water quality issues, can be found in the Interim Lake Okeechobee Surface Wa ter Improvement and Management Plan (SFWMD, 1989a) and a detailed map can be found in Figure 2-2 in Chapter 2

. 

### C1. Kissimmee River Restoration The Kissimmee River Restoration Project will recreate floodplain habitat for use by more than 320 fish and wildlife spec ies and enhance the Kissimmee-OkeechobeeEverglades system. A detailed background of the Kissimmee Rive r channelization is provided in the Surface Water Improvement and M anagement Plan - Update for Lake Okeechobee (SFWMD, 1997a). The restoration is planned in phases, over a 15-year period, to allow incremental funding of c onstruction and land acquisition. The project includes three major components: • Twenty-two continuous, linear m iles of the C-38 canal will be backfilled and the adjacent floodpl ain land will be acquired. This component includes the removal of two of the structures along the canal (S65-B and S65-C), degradati on of levees in the floodplain, and reconstruction of approximately nine miles of river channel. • The headwaters will be revita lized. The primary focus of this component is the storag e/release of water from the upper basin lakes to the Kissimmee River, including expa nsion of canals connecting Lakes Kissimmee, Hatchineha, and Cypres s, improving the structure at the outlet of Lake Kiss immee (S65), and land ac quisition to allow14 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
additional water storage capaci ty in Lake Kissimmee, Lake Hatchineha, Lake Cypress, and Tiger Lake. • A Comprehensive Ecological Evalua tion Program will be designed to evaluate the success of the proj ect in meeting the established restoration goals, to provide for continuous, scientifically-informed fine-tuning of the reconstruction, and adaptive management of the recovering and restored ecosystem.
The State of Florida and the USACE have entered into a partnership to implement the Kissimmee River Restorati on Plan with the SFWMD acting as the local sponsor of this project with a 50-50 cost sh are arrangement. The SFWMD a nd the state have already acquired much of the 85,000 acres required for restoration. In Febr uary 2001, the first of four phases of the restorati on was essentially completed. Se ven miles of the C-38 canal backfilled, 1.5 miles of new ri ver channel were constructed, and 15 miles of the historic Kissimmee River were reconnected. 

### C2. Everglades Restoration Enactment of the 1994 Everglades Foreve r Act established both interim and longterm water quality goals to achieve restorati on and protection of the Everglades Protection Area, which includes the three WCAs and Ever glades National Park. To achieve interim goals, activities are now under way to redu ce phosphorus concentrations to a long-term average of 50 ppb. These activiti es includes the Everglades Construction Project and the EAA Best Management Practices (BMP) Program (SFWMD, 2000a). C2a. Everglades Construction Project The Everglades Construction Project is the first major step in Everglades restoration. The project is mandated in the Everglad es Forever Act (Section 373.4592(4)(a), F.S.) and Phase I of six STAs. When fully constructed, these large (47,655 acres) constructed wetlands will receiv e nearly 1.4 million acr e-feet per year of stormwater runoff from the EAA and adjacent watersheds, and regulatory releases from Lake Okeechobee. Treated water discharged from the STAs will be directed to the Everglades Protection Area to improve water flow, timing, quantity, and quality. Additional treatment will be required before wa ter is discharged to the Everglades to meet all state water quality standards. Land acquisition began in 1994 and was completed in 2001. Construction began in 1997 and the last of the STAs will be co mplete in October 2003. The District is the primary agency responsible for the design, land acquisition, construction, operation, and maintenance of th e Everglades Construction Project. The USACE has been authorized by federal law to construct one of the STAs. The USACE also participated in produci ng a programmatic environmenta l impact statement for the project and issued the fe deral construction permit in 1997. The FDEP is providing technical support and is responsible for the majority of state construction and operating permits (SFWMD, 2000a).Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

15 C2b. Everglades Stormwater Program The Everglades Stormwater Program will improve water quality in basins not addressed by the Everglades Construction Project through monitoring, regulation, and cooperative resource management. The Everglades Stormwater Program identified strategies for complying with water qua lity standards. The EAA BMP Program is administered under the Everglad es Stormwater Program, with the intent of continuing to reduce phosphorus loads from the EAA. The main BMPs include efficient fertilizer application, control of erosi on and sediment, and effectiv e stormwater pumping operations (SFWMD, 2000a).


## D. POINT AND NONPOINT POLLUTION SOURCES
The vast majority of nutrient loading to the lake comes from nonpoint sources, with only minor contributi ons from point sources. Se ctions 373.451- 373.4595, F.S., and Chapter 62-43, F.A.C., require that SWIM plans include the identification of point and nonpoint sources of pollution in the planning area. Table 1-2 is a summary of industrial and domestic wastewater, dairies, Works of the District (WOD), and surface water permits, and waste di sposal sites.


### D1. Point Sources Point sources of pollution are defined as discharges to su rface and ground waters where discrete measures of water flow and wate r quality can be taken. In the Lake Okeechobee SWIM planning area, domestic wa stewater treatment and industrial waste facility discharges are considered point sources. Currently, 69 industrial wa ste facilities are permitted in the Lake Okeechobee SWIM planning area. The permitted facilities consist most ly of dairy operations and power plants. Most of these facilities use la nd application (on-site ponds and/or irrigation) for disposal. Currently, 121 domestic wastewater treatm ent facilities are pe rmitted by the FDEP in the Lake Okeechobee SWIM planning area, with approved cap acities between 0.005 million gallons per day (mgd) to 3.00 mgd. Most of these facilities reuse this water, disposing of the reclaimed wa ter by land applications, such as perc olation ponds, drain fields, and/or irrigation. Three of the facilities use deep well injection for ef fluent disposal, while one, the Avon Park Correctional Institut e in Polk County, uses a surface water discharge. All facilities are re quired, at a minimum, to provide secondary level treatment and basic level disinfection prior to dis posal into ground water. Disinfection is not required for deep well injection.
Domestic wastewater and industrial waste f acilities in the pl anning area are regulated by the FDEP. However, in Palm Beach County, regulation of domestic wastewater facilities with a capacity less than 0.50 mgd has b een delegated to Palm Beach County Health and Rehabilitati ve Services. In addition to approval by these agencies,16 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

surface water discharges also require a National Pollutant Discharge Elimination System permit. This permitting program, previously administered by the USEPA, was delegated to the state in 1995. Surface water discharge permits incl ude water quality-based or technical-based effluent limits . Specific effluent limits ar e based on the presumption that the assimilative capacity of the receiving water is sufficient to handle these additional pollutant loads. 

### D2. Nonpoint Sources Nonpoint source pollution is associated with land use act ivities that do not have a single discrete discharge point. Nonpoint sources are driven by rainfall and runoff, and are the dominant pollution sources in the Lake Okeechobee watershed. These pollution sources are delineated into rural and urban. Rural nonpoint sources include stormwater runoff and are associated with agricultural activities. Stormwater runoff from these activities carries pollutants such as phosphor us from fertilizers, pesticides, and other Table 1-2. Permits in the Lake Okeechobee planning area

Permit Type Permitting Agency Permit Activity General Description Information Provided Total Number Point Sources Industrial Wastewater FDEP Industrial treatment systems Listing of permitted industrial waste facilities within the Lake Okeechobee basin -Facility name -Facility location with latitude/ longitude -Rated capacity 69

Domestic Wastewater FDEP Palm Beach County Health and Rehabilitative Services Private and municipal wastewater facilities Listing of permitted domestic wastewater facilities within the Lake Okeechobee basin -Facility name -FDEP identification number -Facility location -Rated capacity -Disposal method 121

Dairies FDEP Dairy farm BMPs Listing of those dairy farms that have begun the permitting process -Number of cows -BMP system specifications -Percent BMPs completed 26

Nonpoint Sources Works Of the District (WOD) Permits SFWMD Agricultural, industrial, commercial, and nonpoint source BMPs Listing of SWIM Permits within the Lake Okeechobee basin -Permit number -Location and project size -Location of water quality monitoring sites -Listing of water quality data -Land use -Basin BMPs specifications -Tracking of sites that exceed SWIM phosphorus limits 721

Surface Water Management SFWMD Stormwater management systems Listing of SWIM permits within the Lake Okeechobee basin -Permit number -Permittee -Location -Receiving body -Type of facilities -Rate of discharge -Project size 470

Waste Disposal Sites FDEP Landfills Listing of waste disposal sites within the Lake Okeechobee basin -Site name -Location -Status class 16Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

17 agricultural chemicals. Urban nonpoint s ources are also primarily conveyed by stormwater and contain polluta nts associated with urban land uses. The sources of these pollutants range from those tr ansported by direct precipitati on, to pollutants resulting from automobile tire wear, and construction activities. Agricultural activities surrounding the lake are the principal land uses in the area and are responsible for discharging large quantit ies of nutrients to the waters within the watershed through stormwater runoff (Anderson and Flaig, 1995 ). More than 60 percent of the Lake Okeechobee watershe d is used for agriculture ( Table 1-3 ).

Table 1-3. Lake Okeechobee basin land use summary

Land Use Subcategory (Level 3) Lake Okeechobee Basin Total Acreage Percent of Basin Land Use Aquaculture 409 <1% Barren Land 15,528 <1% Citrus Groves 56,690 3% Dairies 12,871 <1% Fallow Crop Land 4,340 <1% Field Crops 10,247 <1% Field Crops – Sugarcane 225,876 12% Floriculture 21 <1% Fruit Orchards 933 <1% Forested Uplands 171,686 9% Horse Farms 980 <1% Improved Pasture 445,119 24% Ornamentals 182 <1% Other 406 <1% Other Groves 72 <1% Rangeland 124,252 6% Row Crops 12,173 <1% Sod Farms 2,324 <1% Transportation, Communication, and Utilities 11,415 <1% Tree Nurseries 2,241 <1% Unimproved Pasture 76,181 4% Urban and Built-Up 55,166 3% Water Bodies 314,662 17% Wetlands 318,479 17% Woodland Pasture 9,725 <1% TOTAL 1,871,978 SUMMARY Agriculture 62% Urban 3% Wetlands/Water 34% Other <1%18 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT


## E. LAND USE E1. Land Use/Land Cover Categories The continuous population influx and agricu ltural growth in South Florida causes rapid changes in land use. Therefore, peri odic land use/land cover mapping is performed every five years to monitor these dynamic changes in land us e. The District has updated the aerial photography (1:40,000) first pe rformed in 1994-1995 by the USGS’ National High Altitude Photography and National Aeri al Photography Program . The existing land use/land cover conditions have been classified utilizing th e FDOT Florida Land Use and Cover Classification System. Th e system is a four-tiered hi erarchal, alphanumeric, land use/land cover coding system th at standardizes mapping across the State of Florida. Level I is the most general classi fication level with categories for agriculture, barren land, forested uplands, rangeland, urban, water, and wetlands. Levels II - IV are subcategories with increasing levels of detail . Land use data are presented in Table 1-3 and Figure 1-3 and has been updated from the previous Lake Okeechobee SWIM plan update (SFWMD, 1997a). Table 1-3 uses Level III subcategories. 

### E2. Land Use Impacts on Water Quality Impacts on water quality are a direct function of intens ity of land use. Land use intensity in the Lake Okeechobee watershed ha s traditionally been low. Ranching, dairy farming, and vegetable farming are the most intensive land uses in the basin that contribute to nutrient (phosphorus and nitrogen) loading to the lake. Nutrients, primarily phosphorus, have been imported into the watershed as animal feed and fertilizer that are used to support improved pastures and da iry operations. A high correlation has been shown to exist between phosph orus imports and phosphorus lo ad to the lake. Wetlands along the flow path to the lake have beendemonstrated to re duce phosphorus loading (Boggess et al., 1995), although many wetlands have been di tched to drain the land for improved pasture, reducing their capac ity to retain water and phosphorus.
Urban land uses within the Lake Ok eechobee watershed contribute to nonpoint pollution that enters the lake. Stormwater fr om these areas, which cover approximately 3 percent of the watershed, may contribute dissolved solids , nutrients, and heavy metals (Whalen and Cullum, 1988). These materials en ter in runoff from lawns and impervious areas such as parking lots, and through on-site wastewater disposal systems. Based on the values from the S-127 and S-133 basins for the 1995-1999 reporting period, the urban contribution of phosphorus to Lake Okeechobee is less than 0.5 percent of the total load, with the balance of the load being c ontributed from agricultural sources ( Chapter 2 ). Stormwater and shallow ground water from agricultural land use may contain pollutants associated with the application of fertilizers, pesticides, and herbicides. Areas north of the lake are used for dairy and cattle farming, whereas areas south of the lake are used for sugarcane, rice, winter vegetables , and sod farming. The major concern is the large amount of primary nutrients (phosphorus and nitrogen) that are discharged to the lake as surface water runoff from these areas. Although tr ace amounts of organics andLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 1: Introduction, Basin Description, and Inventory

19 Figure 1-3. Land use within the Lake Ok eechobee SWIM planning area20 Chapter 1: Introduction, Basin Description, and Inventory Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

trace elements had been detected withinthe basin (Pfeuffer, 1985, 1988), no major problems existed in the watershed or in th e lake itself. A review of 27 years (1973-2000) of data indicated that the water quality associ ated with major inflows has not substantially impaired the designated uses of the lake. Th e instances of trace metal criteria being exceeded are most likely to be due to anthropogenic sources, su ch as agricultural uses of sludge, fertilizers, and pesticides. Nume rous tributary total and fecal coliform measurements were above the criteria during a year of intensive study (Ogburn et al., 1996).Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

21 

## Chapter 2 WATERSHED AND TRIBUTARY WATER QUALITY

The Lake Okeechobee watershed is domin ated by agriculture, which contributes nutrients and other pollutant s that have impacted the ecological condition of Lake Okeechobee. Phosphorus is of particular concern in this system because it has been identified as the key element that contributes to the eutrophi cation of the lake (Davis and Marshall, 1975; Federico et al
., 1981; Joyner 1972; Kissimmee-Okeechobee Basin Report, 1972). To restore the ecological condi tion of Lake Okeec hobee, a 40 percent phosphorus load reduction goal was developed based on data collected from 1973 to 1979 (Federico et al., 1981). The SWIM Act (S ection 373.451-.459, F.S.) was passed in 1987 requiring that a program be established to reduce phosphor us loads to Lake Okeechobee by this amount.
The Interim Lake Okeechobee SWIM Plan (SFWMD, 1989a) set forth a recommended approach for meeting the 40 percent phosphorus reduc tion goal. According to the plan, all tributary infl ows to the lake were required to meet the 0.18 milligrams per liter (mg/l) (180 ppb) performance limitation for tota l phosphorus or ma intain their 1989 discharge concentration, whichever was le ss. Basins that exceeded the 0.18 mg/l limitation were requi red to reduce their phosphorus concentrations and achieve compliance by July 1992. Strategies have been developed to r each these reduction lo ading goals. These include continuing to implemen t the Works of the District (WOD) Program, implementing the CERP, developing BMPs for agricultu re, continuing to model load reduction scenarios, and implementati on of the Lake Okeechobee Pr otection Program and Permits (Section 373.4595(3)-(4), F.S.). Strategies have also beendeveloped to achieve St ate Class I Water Quality Standards within Lake Okeechobee and Cla ss III Water Quality Standards within the lake’s tributaries. These standards are set forth in Chapter 62-302.530, F.A.C. 

## A. GOALS, OBJECTIVES, AND STRATEGIES Goal 1: Reduce pollutant loads from the watershed to protect aquatic life and water qu ality in Lake Okeechobee Objective 1: Bring the overtarget basi ns down to their phosphorus loading targets Strategy 1: Continue to implemen t the WOD Program and develop nutrient management plans for out-of-compliance parcels22 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
Strategy 2: Implement the CERP initiati ves to reduce the loads to the lake through reservoir-assist ed stormwater treatment areas Strategy 3: Develop BMPs for agricult ure and continue modeling load reduction scenarios Objective 2: Develop and implement th e components of the Lake Okeechobee Protection Program and Permits to meet the TMDL target by 2015 Strategy 1: Identify any health or environmental problems associated with spreading wastew ater residuals and chicken manure on land Strategy 2: Institute best availabl e technologies (BATs) on selected dairies to significant ly reduce the export of phosphorus into Lake Okeechobee tributaries Strategy 3: Implement a nonregulat ory, landowner-based initiative for on-site retention of phosphorus and water through the Lake Okeechobee Water Retenti on/Phosphorus Removal Critical Restoration Project Strategy 4: Restore or create isolated wetlands in association with the implementation of BMPs to reduce the phosphorus loading from beef cattle operations and ot her land uses in the watershed Strategy 5: Implement the Phosphorus Source Control Grant Program to fund load reduction projects proposed by applicants Strategy 6: Evaluate two methods of sediment removal technologies selected as part of the sediment removal project under way in Lettuce Creek Strategy 7: C onduct an economic analysis of all feasible on-farm and regional phosphorus control al ternatives to reduce phosphorus loads to the recommended levels Objective 3: Achieve State Class I Water Quality Standards (Chapter 62-302, F.A.C.) within Lake Okeechob ee, and Class I II Water Quality Standards within the lake’s tributaries Strategy 1: Support the development a nd implementation of a comprehensive plan to address th e occurrence of Class I/Class III water quality criteria being exceeded within Lake Okeechobee and its tributaries to fulfill the re quirements of the Lake Okeechobee Operating PermitLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

23 Strategy 2: Establish additional monitoring of biological conditions and trace metals during inflow conditions to document whether the inflows from tributar ies to Lake Okeechobee meet the standards of their de signated usage class Strategy 3: Establish monitoring to de termine the significance of and the potential causes of low dissolved oxygen in inflows from tributaries to the lake before ma nagement strategies are evaluated Strategy 4: Sample the tributaries for total dissolved solids on a regular basis, since Class I criter ion for total dissolved solids was exceeded over 25 percent of the time in inflows from the tributaries to Lake Okeechobee Strategy 5: Modify the District's m onthly monitoring program to include iron analysis to facilitate a more conclusi ve assessment of the potential need for management measures to control trace metals within the tributaries Strategy 6: Reduce the list of organi c parameters from the supplemental monitoring program to focus on compounds that are known to have potential source s in the watershed, such as pesticides, herbicides, and petroleum hydrocarbons Strategy 7: Recommend quarterly sampling for organics, with the schedule being based on seasonal us es of agricultural chemicals and/or periods of inflow to the lake Strategy 8: Conduct a survey to establis h the extent and source of total and fecal coliforms that exceed the criteria Strategy 9: Determine the applicability of additional management strategies for the following: 1) canals, using sediment removal and constructed wetlands, 2) marina s, using liquid waste management and boat maintenance control me asures, and 3) establishing alternative, more appropriate, cr iterion for some parameters in order to prevent Class I/Class III water quality criteria for the tributaries from being exceeded24 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT


## B. PHOSPHORUS LOADS AND TARGETS BY BASIN

The SFWMD Technical Publication 81-2 (Federico et al., 1981) developed a 40 percent phosphorus load reduction goal based on a modified Vollenweider model. This model, developed for Lake Ok eechobee using data from 1973 to 1979, predicts the in-lake phosphorus concentration based on external load s, external flow, and turnover time (i.e., the amount of time it would ta ke the lake to empty based so lely on surface outflows). The agreement between model predic tion and yearly average obser ved data was quite good for the 1973 to 1979 ( Figure 2-1)

.

Given that the target in-lake phosphorus concentration and the TMDL is 40 ppb, the model can be rewritten to determine the phosphorus loads that would reach that target concentration. This loading goa l, which averaged 397 tons pe r year, was used to set the criterion for each basin ( Figure 2-2 ) by determining the fl ow-weighted average concentration of phosphorus that would result in 397 tons or less entering the lake. This value was 180 ppb at each inflow point. Thus, the 1989 Interim Lake Okeechobee SWIM Plan (SFWMD, 1989a) required that all tributary inflows to th e lake should meet the 180 ppb performance limitation fo r total phosphorus or main tain their 1989 discharge concentration, whichever was less. Targets are developed for each basin base d on average annual, flow-weighted total phosphorus concentrations. These targets are adjusted for va riations in discharge. To calculate the observed load from each basi n, the observed concentration is multiplied by flow. Excess phosphorus loads are calculated as the difference between the observed and target loads. The phosphorus loads and targets for each basin for 1990 to 1994 and 1995 to 2000 are presented in Tables 2-1 and 2-2 , respectively. 0 10 20 30 40 50 60 70 80 90 100

1973 1974 1975 1976 1977 1978 1979Total Phosphorus (ppb) Observed

Predicted

Figure 2-1. Comparison of the modified Vollenweider model total phosphorus predictions to observed data for 1973 to 1979Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

25 Collectively, the flow-weighted mean conc entration from controllable sources of these tributaries for the five-year period following full implementation of BMPs (1990 through 1994) was 243 ppb ( Table 2-1 ). During this period, 19 basins were at least 10 percent above their target loads, and 8 basins were at least 10 perc ent below their target loads. The other 2 basins were within plus or minus 10 percent of their target loads. The excess loading was 140 tons per year based on target loads fo r each basin. The S65 basins (A through E) were not separated from each other because the measurements at these structures do not capture the seepage and bypass flows, which are significant. To determine the basin loads from S65A thr ough S65E, the discharge out of S65 (Lake Kissimmee) was subtracted from the discharge from S65E. Th e resultant is assumed to be the contributions of flow and load from the S65A through S65E basins. S-65 A

S-65B

S-65D S-65C

C-41 A S-154

FISHE A

TINGCREEK S-65E

C-41 S-133 C-40 S-154C L-59E

L AKE OKEECHOBEE S-135 L-48 L-59W L-60E L-61E L-49 L-60W L-61W S-131 S-191

NICODEMUS SLOUGH

Figure 2-2. The drainage basins that contribute nutrient enriched runoff to Lake Okeechobee26 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Table 2-1. Phosphorus (P) loads and targets by basin in the Lake Okeechobee watershed for 1990-1994

Basin Area (square miles) Target Total

P (ppb) 1990-1994

Discharge (acre-feet) Target Load (tons/ year) FlowWeighted

Total P (ppb) Average (tons/ year) Over/ Under (tons/ year) Percent Over/ Under Target Controllable Sources 715 Farms (Culvert 12A) 4 180 9,293 2.3 147 1.9 -0.4 -18% C-40 Basin (S-72) 87 180 23,096 5.6 415 13.0 7.3 130% C-41 Basin (S-71) 176 180 52,956 12.9 417 30.0 16.9 131% S-84 Basin (C41A) 180 100 47,478 6.4 143 9.2 2.7 42% S-308C (St. Lucie-C-44) 190 180 89,043 21.7 152 18.4 -3.3 -15% East Beach DD (Culvert 10) 10 180 7,973 1.9 508 5.5 3.6 182% East Shore DD (Culvert 12) 13 130 11,958 2.1 191 3.1 1.0 47% Fisheating Creek 462 180 178,676 43.6 161 38.9 -4.7 -11% Industrial Canal 23 180 22,210 5.4 110 3.3 -2.1 -39% L-48 Basin (S-127) 32 180 13,267 3.2 246 4.4 1.2 37% L-49 Basin (S-129) 19 180 8,595 2.1 133 1.6 -0.5 -26% L-59E 15 160 4,512 1.2 245 1.5 0.6 49% L-59W 15 160 5,867 1.6 163 1.3 0.0 2% L-60E 6 100 877 0.1 194 0.2 0.1 55% L-60W 6 100 298 0.1 247 0.1 0.0 36% L-61E 22 90 4,805 0.7 153 1.0 0.5 63% L-61W 22 90 7,308 1.1 101 1.0 0.1 12% Taylor Creek/Nubbin Slough (S-191) 188 180 108,825 26.6 609 90.0 63.6 239% S-131 Basin 11 150 7,965 1.6 103 1.1 -0.5 -31% S-133 Basin 40 180 24,248 5.9 253 8.3 2.4 40% S-135 Basin 28 160 21,557 4.7 98 2.9 -1.8 -39% S-154 Basin 37 180 19,550 4.8 728 19.3 14.6 306% S-2 166 160 31,424 6.8 231 9.8 3.0 44% S-3 101 150 5,904 1.2 179 1.4 0.2 19% S-4 66 180 17,766 4.3 175 4.2 -0.1 -3% S-65A, B, C, D, E 749 113 265,192 55.9 257 92.4 35.6 64% South Florida Conservancy DD (S-236) 15 90 3,407 0.4 116 0.5 0.1 29% South Shore/South Bay DD (Culvert 4A) 7 80 7,195 0.8 113 1.21 0.4 54% Nicodemus Slough (Culvert 5) 28 60 2,503 0.3 59 0.2 -0.1 -22% Controllable Totals 1,003,746 226 243 366 140 62%
Uncontrollable Sources Rainfall - - 72.0 S-65 (Lake Kissimmee) - 733,505 38 39.3 Lake Istokpoga (S-68) - 183,872 29 7.2 S-5A Basin (S-352-West Palm Beach Canal) - 2,048 0 East Caloosahatchee (S-77) - 3,616 245 1.2 L-8 Basin (Culvert 10a) - 68,503 99 9.2 Uncontrollable Totals 991,544 129 Total Loading 1,995,291 495 Target Loading (concentration-based) 355 140 39% Vollenweider Target 399 96 24%Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

27 Table 2-2. Phosphorus (P) loads and targets by basin in the Lake Okeechobee watershed for 1995-2000

Basin Area (square miles) Target Total

P (ppb) 1995-2000 Percent Change

Over/ Under Target Discharge (acre-feet) Target Load (tons/ year) FlowWeighted

Total P (ppb) Average (tons/ year) Over/ Under (tons/ year) Percent Over/ Under Target Controllable Sources 715 Farms (Culvert 12A) 4 180 12,999 3.2 96 1.7 -1.5 -46.6% -28% C-40 Basin (S-72) 87 180 13,558 3.3 508 9.4 6.0 182.0% 52% C-41 Basin (S-71) 176 180 46,001 11.3 429 26.8 15.5 138.1% 7% S-84 Basin (C41A) 180 100 57,298 7.8 149 11.6 3.9 49.5% 7% S-308C (St. Lucie-C-44) 190 180 34,134 8.4 185 8.6 0.3 3.0% 18% East Beach DD (Culvert 10) 10 180 13,206 3.2 644 11.6 8.3 257.9% 75% East Shore DD (Culvert 12) 13 130 14,439 2.6 164 3.2 0.7 26.0% -21% Fisheating Creek 462 180 210,576 51.5 178 50.9 -0.6 -1.2% 10% Industrial Canal 23 180 20,672 5.1 103 2.9 -2.2 -43.1% -4% L-48 Basin (S-127) 32 180 26,457 6.5 230 8.3 1.8 27.7% -9% L-49 Basin (S-129) 19 180 14,630 3.6 91 1.8 -1.8 -49.3% -23% L-59E 15 160

No data available L-59W 15 160 L-60E 6 100 L-60W 6 100 L-61E 22 90 L-61W 22 90 Taylor Creek/Nubbins Slough (S-191) 188 180 97,154 23.8 651 86.0 62.2 261.7% 22% S-131 Basin 11 150 9,180 1.9 115 1.4 -0.4 -23.3% 8% S-133 Basin 40 180 23,924 5.9 182 5.9 0.1 1.0% -39% S-135 Basin 28 160 22,845 5.0 116 3.6 -1.4 -27.4% 11% S-154 Basin 37 180 26,602 6.5 826 29.9 23.4 358.9% 53% S-2 166 160 29,235 6.4 197 7.8 1.5 22.9% -21% S-3 101 150 11,568 2.4 213 3.4 1.0 42.1% 23% S-4 66 180 33,801 8.3 215 9.9 1.6 19.6% 22% S-65A, B, C, D, E 749 113 283,267 43.4 213 81.9 38.5 88.7% 25%South Florida Conservancy DD (S236) 15 90 14,494 1.8 111 2.2 0.4 23.1% -6% South Shore/South Bay DD (Culvert 4A) 7 80 7,893 0.9 101 1.1 0.2 26.5% -27% Nicodemus Slough (Culvert 5) 28 60 Controllable Totals 1,023,934 212 266 370 158 74.2% 12%
Uncontrollable Sources Rainfall - - 72.0 S-65 (Lake Kissimmee) - 885,858 84 100.3 Lake Istokpoga (S-68) - 292,451 59 23.3 S-5A Basin (S-352-West Palm Beach Canal) - 18 248 0.0 East Caloosahatchee (S-77) - 342 244 0.1 L-8 Basin (Culvert 10a) - 52,953 97 6.9 Uncontrollable Totals 1,231,622 121 203 Total Loading 2,255,556 573 Target Loading (concentrationbased) 415 158 37.9% -2% Vollenweider Target 371 201 54.3% 30%28 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
The next six-year period, 1995 to 2000, the overall flow-weighted concentration from controllable sources increased slightly to 266 ppb ( Table 2-2 ). Ten basins had concentrations at leas t 10 percent above their target and 6 basins had c oncentrations at least 10 percent below. Discharges for th e L59, L60, and L61 basins, and Nicodemus Slough were not available for this period, and thus they were not included in this calculation. However, in the 1990 to 1994 period, they accounted for only 5.1 tons of phosphorus loads or less than 1.4 percent of the total. The excess loading for the 1995 to 2000 period was 158 tons per year based on the flow and target concentrations for each basin ( Table 2-2 ). This was a 2 percent decrease compared to the 1990 to 1994 period ( Table 2-1 ). However, based on the Vollenweider model target, the excessive loading had incr eased by 30 percent comp ared to the 1990 to 1994 period. This is because the Vollenweide r target includes both controlled and noncontrolled loads contributing to Lake Okeechobee. The highest inflow concen trations were found in the S-154 and S-191 basins, where dairies are abundant and where the ma jority of the out-of- compliance WOD sites that are out of compliance ar e located. These basins, along with the S65 basins, account for most of the overtarget lo ad, and, if they met their ta rget concentrations, would collectively bring overall loading to Lake Okeechobee very close to the target. These basins currently receive intensive study, regulatory scrutiny, and are the focus of remediation activities. These basins are also the focus of the landowner-based initiative described later in this chapter. The Kissimm ee River, which runs through the S65 basins, is currently being restored. As of this writing, the S65B structure has been removed and over seven miles of the C-38 canal has been plugged and fifteen miles of historic Kissimmee River have been reconnected. Comparing noncontrollable loads in the two periods shows a disturbing trend. Subtracting out the atmospheri c loads gives a noncontrollable load of 57 tons during the 1990 to 1994 period ( Table 2-1 ), and 131 tons in the 1995 to 2000 period ( Table 2-2 ). This large increase of 1995 noncontrollable surface discharges can only partially be explained by an increase in discharge. Th e flow-weighted average concentration of discharge from Lake Istokpoga and Lake Ki ssimmee more than doubled over this time period.


## C. WATERSHED REGULATORY PROGRAMS

The Surface Water Improvement and Management (SWIM) Plan - Update for Lake Okeechobee (SFWMD, 1997a) published in 1997 disc ussed several programs that had already been implemented to achieve th e phosphorus reduction in runoff from the watershed. A brief description of these programs and their curren t status is provided in this section.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

29 

### C1. Dairy Rule In June 1987, the Florida Department of Environmental Regu lation, now known as the Florida Department of Environmental Protection (FDE P) enacted the Dairy Rule (Chapter 62-670, F.A.C.). The Dairy Rule requi red that all dairy operations within the Lake Okeechobee watershed and its tribut aries implement BMPs for the purpose of reducing phosphorus inputs to the lake. A total of 49 dairies, the majority located in the Taylor Creek/Nubbins Slough and Lowe r Kissimmee River basins, came under jurisdiction of the rule. The Dairy Rule did not es tablish a specific off-site phosphorus discharge concentration limitation, but required BMPs to be incorp orated into the operation of dairies. These BMPs needed to provide reasonable assurances that each dairy could meet state water quality standards (Chapter 62-670, F.A.C.) and that acceptable phosphorus levels in off-farm discharges would be achieved (Albers et al., 1991). Although the Interim Lake Okeechobee SWIM Plan (SFWMD, 1989a) esta blished a maximum discharge limitation of 1.2 mg/l total phos phorus, the dairies were exempted from permitting and enforcement under the WOD Program, since they were under the jurisdiction of the Dairy Rule. Implementation of dairy BMPs was complete d at 30 dairies. Four of these dairies have since closed, one of which was purchas ed by the District in 1994 with Save Our Rivers (SOR) funds and one was purchased fo r use as a reservoir assisted stormwater treatment area (RSTAS) that is part of a critical restorati on project. Currently, only 26 dairies have operating permits of which 25 are active at this time. One dairy has temporarily closed while maintaining the Dairy Rule permit in an active status with the option of reopening at a later date. The FDEP continues to monitor the active dairies for compliance with their Dairy Rule operating pe rmits. Nineteen dairies participate in the program. 

### C2. Works of the District/Regul ation of Nondai ry Land Uses After the adoption of the Interim Lake Okeechobee SWIM Plan (SFWMD, 1989a), Chapter 40E-61, F.A.C., was developed by the SFWMD with an effective date of November 1989. The rule establis hed criteria to ensure that use of, or connection to, a WOD project or lands would be compatible with the SFWMD’ s ability to carry out the water quality objectives found in several SFWMD programs, including those stated in Section 373.016, F.S.; Chapter 62-40, F.A.C.; and the SWIM Act as outlined in Sections 373.451 through 373.459, F.S., and Chapter 40E-61, F.A.C. This regulatory program applies to all nondairy land uses and areas of dairies not covered by the Dairy Rule that discharge to WOD projects or lands located within the Lake Okeechobee drainage basin. Works of the District project s include waterways, canals, water control structures, rights-of-way, wetlands, remnant oxbows or sl ough, lakes, and stream s that the District owns or has the responsibility of managing. A ll land uses within the basin are subject to this rule. However, the type of permit required depends on seve ral factors: the type of land30 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

use, the extent to which the use is a contri butor of phosphorus to th e lake, and the basin in which the land is located. Th e deadlines for submittal of permit applications were prioritized to bring the most problema tic basins into compliance first. From January 1990 through March 2001, 721 pe rmits were issued in the following basins: S-191, S-154, S-127, C-38 Pool E, S-4, S-71, S-72, Industrial Canal, S-133, Culvert 10 (East Beach Draina ge District), C-38 Pool D, Culvert 12A (715 Farms), Fisheating Creek, and S-154C. In all of the 14 priority basins, initi al permitting of all problematic parcels equal to or greater than five acres in size is complete. Administrative maintenance of the permit files is an ongoing activity, as land use and ownership changes require permit modifi cations and transfers. In priority basins, individual permits were required for certain land uses and general (Notice of Intent) pe rmits were required for othe r land uses. Al l other basins required a general (no Notice of Intent) permit. Provided in Table 2-3 is a simplified overview of the various land us es and the type of permit required by the SFWMD. In the basins north of the lake, the primary nondairy land uses are improved pasture for beef cattle and agricultural us es such as sod production.

In the regulatory program, us ers of the WOD are required to meet specific off-site phosphorus discharge concentrat ion limitations. If the SFWMD monitoring data indicate that the probability of the average annual off- site discharge concentr ation not being met is greater than 50 percent, the affected landowne r is required to take corrective measures to bring discharges from the pr operty into compliance with th e rule. The SFWMD conducts a two-pronged water quality moni toring program to identifyhigh phosphorus source areas within the basin and to distinguish betwee n landowners who are incompliance and those who are not. Routine biweek ly water quality monitoring is conducted on permitted parcels. At least one year of monitoring is required on all individual perm its to document compliance status. Unfortunately , due to limited resources it has not always been possible to monitor all individual pe rmits. In some cases moni toring conducted downstream of several permit holders has been used to establish comp liance. A nonroutine, site specific surveillance monitoring program is also conduc ted throughout the basin to identify high phosphorus source areas in both the priority and nonpriority basins. Table 2-3. Works of the District permits r equired for various land uses General Permit (Notice of Intent) Individual Permit
Urban stormwater Golf courses Sugarcane Horse farms Nurseries Land spreading of sludge Sod farms Dairy land use not covered by Dairy Rule Improved pasture Vegetable farms/row crops Heifer farms Poultry farms Hog farms Goat farmsLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

31 A formal notification of pot ential noncompliance is sent to owners of parcels discharging surface waters wi th high phosphorus concentrat ions. Once noncompliance is confirmed, a permittee is required to deve lop a nutrient manage ment plan with an implementation schedule. This pl an is incorporated into th eir SWIM permit as a permit addendum modification (PAM). If SWIM phos phorus limitations ar e not achieved within one year of issuance of the PAM, additional BMPs and corr ective actions may be required. The effectiveness of identified corrective actions are evaluated using existing water quality and soils data along wi th the field-scale Everglad es Agricultural Area Model (EAAMOD). This information is then documented in a formal technical assessment and initiated through a consent agreement between the SFWMD and the landowner. The following list includes BMPs incorpor ated into the nutrient management plans for the WOD sites that are out of compliance: • Remove residual phosphorus in soils in former high-intensity areas (HIAs) through a nutrient manageme nt program of forage production (sorghum, oats, and Bahia, Alicia Bermuda, and improved grasses) with subsequent harvest and export • Develop grassed buffer areas ar ound existing areas where animals congregate • Minimize or eliminate the devel opment of new animal congregating areas by mobilizing shade, water, and feeding ar eas and placing these areas away from tributaries in well drained, sandy areas • Eliminate cattle from tributar ies and develop ro tational grazing strategies that move cattle away from sensi tive areas during the peak rainfall periods • Eliminate phosphorus fe rtilizer applications near tributaries • Limit the overdrainage of wetland soils • Restore wetlands that have been ditched or drained • Reduce animal density (voluntary) • Reduce phosphorus import in animal feeds • Use soil amendments to improve soil binding capacity and enhance availability of phosphorus for plant uptake • Use the University of Florida’s Institute of Food and Agricultural Sciences (IFAS) soil testing data and subsequent fert ilizer application recommendations to optimize plan t growth and minimize nutrient runoff • Eliminate off-site disc harge from areas that have a high density of animals • Scrape sediment and remove from the site or spread in upland areas • Use a combination of chemical and biological treatm ent of hot spot ditches32 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
• When maintaining ditches, remove and spread sediments in upland
areas • Drag and spread manure to reduce the accumulation of manure in high traffic areas to distribute nutrients more evenly across the pastures • Develop balanced phosphorus budg ets as part of a nutrient management plan As of March 2001, the WOD noncomplianc e activity summary included 28 PAMs and 8 Consent Agreements. Sixt een permittees that have in itiated corrective actions have achieved the SWIM phosphorus lim itation for their respective land use. Fourteen of the permittees that have developed corrective actions in accordance with their PAM have since achieved their off-site phosphorus limi tation. The remaining two permittees have achieved compliance following the implementation of corrective actions called for in their Consent Agreement.


## D. COMPREHENSIVE EVERGLADES RESTORATION PLAN
The Central and Southern Florida Project Comprehensive Review Study, Final Integrated Feasibility Report and Progra mmatic Environmental Impact Statement (USACE and SFWMD, 1999) reco mmended a comprehensive pl an for the restoration, protection, and pres ervation of the water resources of Central and South Florida, including the Everglades ecosystem, while providing for the other water-related needs of the region. The comprehensive review study, referred to as the Restudy, proposed project components and determined their potenti al impacts on existing resources . The Florida Legislature passed the Restudy Bill (Senate Bill 1672) in April 1999, and authorized the SFWMD to be the local sponsor of these projects. The Restudy projects are being implemented through the Comprehensive Everglades Restoration Plan (CERP). The CERP contains over 60 major components that i nvolve either struct ural or operational changes to the existing C&SF Project. The basic approach of th e plan is to capture most of the 1.7 billion gallons of water per day that on average is discharged through project canals to the Atlantic Ocean and the Gulf of Mexico and use it to supplemen t water supply and to achieve the restoration of natural sy stems, including Lake Okeechobee and the Everglades. Restoration of natural areas will be accomplish ed by restoring more natural flows of water, improving water quality, and establishing more natural hydroperiods. Major features of the CERP that directly affect th e Lake Okeechobee watershed include the following: • Taylor Creek/Nubbin Slough Reservoi r-Assisted Storage Treatment Area: a 5,000-acre storage area wi th a 5,000-acre wate r treatment area • North of Lake Okeechobee Storag e Reservoir: a 17,500-acre storage area with a 2,500-acre wa ter treatment area • Lake Okeechobee Water Quality Tr eatment facili ties: a 1,775-acre treatment area in the S-154 Basin; a 2,600-acre tr eatment area in theLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

33 S-65D Basin; and plugged drainage ditches th at will result in the restoration of 3,500 acres of wetlands • Lake Okeechobee Tributary SedimentControl: capturing or removing phosphorus-laden sediment in tributar ies to prevent it from reaching Lake Okeechobee • Lake Okeechobee Aquifer Storage and Recovery (ASR): a series of ASR wells around the lake with 1 billion gallons per day capacity to be proceeded by pilot testing


## E. CURRENT MANAGEMENT PROGRAMS
Effective phosphorus control strategies can only be successful ly implemented if we understand the source and fate of phosphorus in uplands, we tlands, and streams of the watershed. To achieve this understanding, seve ral research projects were conducted to develop the understanding of the movement of phosphorus in the watershed. Completed and ongoing research projects are described inthis section. Key results presented here have implications for the deve lopment of cost-effective a nd sustainable BMPs to reduce phosphorus loads from the watershed in to adjacent aquatic systems. 

### E1. Phosphorus Budgets Phosphorus is of particular concern in this system because it has been identified as the key element that contribut es to the eutrophication of th e lake (Davis and Marshall, 1975; Federico et al., 1981). Early research indicated that phosphorus loads originated from agricultural nonpoint sour ces, mainly beef cattle ranc hes and dairy fa rms (Boggess et al. 1995). Based on data from 1985 to 1989, Bogge ss et al. (1995) estimated that the total phosphorus import into 22 basins of the northern Lake Okeechobee watershed was approximately 3,500 tons per year. The phosphor us import was primarily in the form of pasture fertilizer and dair y feed. In additi on, approximately 33 0 tons of phosphorus entered the watershed in the fo rm of rain. The total phosphorus export in milk, cows, and crops was about 900 tons per year. In additi on, about 330 tons of phos phorus reached the lake per year. From these values, it was es timated that the net phosphorus import of 2,600 tons per year was retained inupland soils and the transport system (streams and wetlands). This imbalance in import versus export cont inues to add to the build-up of phosphorus in the northern Lake Okeechobee wate rshed. This has caused the concern that unless controls are placed on importing phosphorus, attempts to restore Lake Okeechobee will be delayed or fail altogether. The study by Boggess et al. (1995) was based on phosphorus and materials budget information collected ten years ago, which is prior to the implementation of many BMP programs. Since then, land uses and associ ated management practices have changed dramatically. A study is being conducted to update the phosphorus budget information, taking into account many of the land management changes that have occurred in recent years. This new phosphorus budget will use th e most recent phosphor us import and export data available, as well as examine phosphorus sources that were not explored previously,34 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
such as sludge applicati on, poultry manure, on-site se ptic systems, and phosphorus discharges via subsurface fl ow. This study also includes analyzing possible relationships between net phosphorus imports and basin charact eristics (land use ty pe, soil type, stream type, etc.) for each basin, identifying basi n characteristics that affect net phosphorus imports and storage, and devel oping a graphical user interface to viewinput data (farms, drainage basins, hydrographic features, land uses, and soil types) and phosphorus budget results (import and export) using ArcViewTM, a geographi c information system. The updated phosphorus budget informat ion will be available inMarch 2002. The final report and the graphical user interf ace are due in April 2002. Base d on this information, we will determine how much the net import of phosphorus to the watershed has changed over the past decade, and what sources are particularly problematic. Then, we can target those problem sources and determine ef fective means to control them. 

### E2. Phosphorus Assimilation The WOD Rule limits total phosphorus c oncentrations in runoff leaving land parcels (SFWMD, 1989a). The total phosphorus concentration limitations range from 0.18 to 1.2 mg/l. These limitations were devel oped based on estimated phosphorus assimilation in channels and wetlands along measured fl ow paths. A first order exponential decay function was used to describe phosphorus assimilation with flow travel distance in channels and wetlands (SFWMD, 1989a). Ho wever, the assimilation of phosphorus is actually influenced by divers e physical, chemical, and biologi cal factors. These factors include phosphorus sorption/deso rption by sediments, water fl ow rate and travel length, and phosphorus uptake by vegetation. If phosphorus load estimates fromthe watershed are to improve, it will be necessa ry to develop better phos phorus retention/assimilation algorithms for describing phosphor us transport dynamics. Thes e algorithms are critical to watershed nutrient management. A second order exponentia l decay function was us ed in the updated Lake Okeechobee Agricultural Decision Support Sy stem (LOADSS) model. The function included a temporal adjustment of flow rate on an annual scale (SWET, 1999). To take into account of additional bi ogeochemical processes with in various flow conveyance systems (e.g., overland, channels, natural streams, and wetlands), a study was conducted recently to enhance the existing algorithm us ed in the LOADSS model. After examining the available data, the contractor concl uded that the data resources for the Lake Okeechobee watershed are insuff icient to advance the curr ent phosphorus assimilation algorithm. Therefore, the focus of future studies should be ga thering the necessary data to properly quantify the phosphorus assimilation in specific water conveyance systems. 

### E3. Potential Phosphorus Load Reduction from Nondairy Out-of-Compliance Site s and Dairy Hot Spots
E3a. Beef Cattle Waste
Cattle waste from the basi ns north of Lake Okeechobee has been identified as a source of phosphorus contributing to the accelerated eutrophi cation of the lake. The WODLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

35 program issues permits and m onitors phosphorus concentrat ions in surface runoff from nondairy land parcels that are 0.5 acres or greater in size. A site is considered out of compliance if the average total phosphorous co ncentration in the runoff within a 12-month period exceeds the regulatory standard for the site. Past ure sites with excess phosphorus discharge are potential targ ets for corrective management actions designed to reduce phosphorus loads. Zhang et al. (2001) indicates that, from October 1998 to September 1999, 77 outof-compliance sites discharged an estimated 51 tons of p hosphorous on an average annual basis, of which an estimate d 24 tons per year reached La ke Okeechobee. The remaining estimated 27 tons of phosphorus load were retained by streams and wetlands. An estimated 16 tons of phosphorus load reduction per year w ould be expected if phosphorus concentrations in runoff fromthese sites do not exceed the discharge limits. If the land uses were changed to native range land withan off-site annual total phosphorus areal loading rate of 0.102 pound per acre, an estim ated 23 tons of phos phorus load reduction would be expected on an average annual ba sis from these out-of-compliance sites. Of the 77 out-of-compliance sites, 12 site s had a phosphorus loading rate greater than 2.5 pounds per acre. These sites were recommended to be placed on the priority list for the Lake Okeechobee Water Retention/P hosphorus Removal Cr itical Restoration Project. Ongoing research is be ing conducted by the Di strict to identify remedies and associated costs for these sites and to evaluate the cost-effectiveness of strategies for reducing phosphorus loads. E3b. Dairy Waste Dairy waste from the northern Lake Okeec hobee watershed has been identified as a source of phosphorus contributing to the accelerated eutrophication of Lake Okeechobee (Ray and Zhang, 2001). Sites we re identified as priority sites if the average total phosphorus concentration in runoff exceeded regulatory si te limitations from October 1998 to September 1999. These site s are located at both active and former dairies. The phosphorus discharge limit for act ive dairy sites is 1.2 mg/l. Th e discharge limitations for former dairy sites vary base d on current land use and must not exceed 1.2 mg/l. Twentyone priority sites were identified within the northern Lake Okeechobee watershed. These sites produce an estimated 18.1 t ons of phosphorus load annuall y, of which an average of 9.5 tons of phosphorus load reaches the lake on an annual basis. The remaining 8.6 tons of phosphorus load were retained /assimilated by str eams and wetlands in the discharge transport system between the si tes and the lake. If none of th e sites were to exceed the 1.2 mg/l phosphorous runoff concentr ation, off-site loads would be reduced by an estimated 10.7 tons, with the loads to the lake reduced by 5.8 tons. Furthermore, if all dairy sites were converted to improved pa sture with a discharge concen tration limitation of 0.35 mg/ l, off-site loads would be reduced by an esti mated 15.7 tons and loads to the lake would be reduced by 8.3 tons.
These load estimates do not include the out er pastures associated with the dairies. In 1999, three monitoring stations were added to the discharge points of the dairy pastures. This information will be used to calibrate a computer simulation model that will estimate36 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
the phosphorous load from all dairy pastures. This inform ation will be included in the updated study. Due to the 2000 drought, not enough samples were collected to complete this study by the original target date of December 2001. The study will be extended until an adequate number of samples ha ve been collected and analyzed. 

### E4. Modeling Efforts
To determine the effectiveness of indi vidual BMPs, a systematic methodology for cross-comparison of alternativ e strategies for phosphorus lo ad reduction, including fieldscale, farm-scale, or basin- scale phosphorus reduction practic es, needed to be developed. The need to evaluate practices at different scales resulted in the development of field- and basin-scale computer models . Projects include developm ent and application of the following models: (1) the EAA model upgrad e; (2) the next ge neration field-scale Nonpoint Source Pollution Model; (3) the next gene ration Watershed Phosphorus Transport Model; and (4) the Lake Okeechob ee Agricultural Decision Support System. General overviews and applications of each project are presented below. E4a. EAA Model Upgrade A field hydrologic and nutri ent transport model (F HANTM) (Tremwel and Campbell, 1992), has been used in the Lake Okeechobee watershed as a tool to evaluate the effectiveness of BMPs implemented on parcels out of compliance with the WOD phosphorus discharge concentrat ion limitations (Gornak and Zhang, 1999). Unfortunately, FHANTM does not handle the p hosphorus soil interaction we ll. Zhang and Gornak (1999) evaluated three field-scale models, FHANTM, FHANTM 2.0, and the EAA Model (EAAMOD), to determine which was best suit ed for use in the WOD program. It was concluded that none of the models were sufficient, but that EAAMOD had the most potential. Therefore, EAAMOD was upgraded in 2000 for use in the Lake Okeechobee WOD program. In addition to upgrading the field-scal e version of EAAMOD , the field-scale model is to be integrated into a farm-scale model (EAAMOD WAMView). A field-scale model evaluates the land use from one pasture. The advantage of th e farm-scale model is that an entire farm can be simulated atone time rather thansimulating the fields individually. Final adjustments to the farm-s cale model are being made at this time. E4b. Nonpoint Source Pollution Model
Runoff from fields in th e Lake Okeechobee watershe d is a major source of phosphorus entering the lake. Th e ability to estim ate edge-of-field phosphorus loads and potential load reductions due to BMPs is important to pr ograms whose goal is to limit the amount of phosphorus entering th e lake. Examples of such programs are WOD, isolated wetland restoration, and rese rvoir-assisted STAs. The No npoint Source Pollution Model estimates the impacts that land use pr actices and BMPs ha ve on reducing phosphorus loads leaving a field.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

37 The Nonpoint Source Poll ution Model has hydrology and nutrient transport components and a graphical us er interface. The hydrology co mponent computes overland and ground water flows leavi ng a field. The nutrient tran sport component computes phosphorus concentrations in these flows, an d can be expanded to include nitrogen should the need arise. The graphical user interface facilitates use of the model by automating many modeling functions including input datapreparation, model execution, and output analysis. The Nonpoint Source Pollution Mode l also will be a co mponent of the basinscale Phosphorus Transport Model. E4c. Phosphorus Transport Model The Phosphorus Transport Model was orig inally developed and applied to the Taylor Creek basin (Zhang et al., 1996). It gave close esti mates of flow and phosphorus loading on a seasonal basis. The next gene ration of the Phosphorus Transport Model operates on a daily time step and it contains two submodels: a field- scale submodel and a channel system submodel. The field-scale submodel will simulate phosphorus loads leaving individual fields in a watershed and is being deve loped by the Next Generation Field-Scale Nonpoint Source Po llution Model project. The ch annel system submodel will receive runoff and phosphorus loads leaving fields as input and simulate phosphorus transport and removal by streams, canals, and wetlands. The channel system submodel will have a hydrology componen t to simulate water moveme nt, and a transport component to simulate phosphorus trans port and removal. Also, a gra phical user interface will be developed to facilitate m odel use by automating many m odeling functions, including input data preparation, model exec ution, and output analysis. The Phosphorus Transport Model can be used to evaluate th e effectiveness of BMPs on re ducing phosphorus loads from the watershed to the lake. The final product is due in July 2003. E4d. Lake Okeechobee Agriculture Decision Support System The Lake Okeechobee Agriculture Decision Support System (L OADSS) is a tool based on a geographic information system that evaluates the effects of different land use practices on reducing phosphorus loads and the economic impact of these practices on the surrounding area (Negahban etal., 1995). LOADSS was origin ally developed with data collected before 1987. The model was updated in 1997 with 1995 conditions (SWET, 1999). The updated LOADSS model c ontains the most current land use data and economic information. Land parcel boundaries developed for the WOD rule also were incorporated into the LOADSS database. Th e update created a ne w database allowing users to conduct a phosphorus loading analys is at a finer spatial scale. The updated economics database included the cost of c onverting one land use to another. Within LOADSS, a land use and phosphor us management plan can be developed using a menudriven user interface. The updated LOADSS model allows the Di strict to evaluate what-if scenarios and determine the effectiveness of phosphorous c ontrol practices on reducing phosphorus loads to the lake.38 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT 

### E5. Optimization of BMPs for Beef Cattle Ranching in the Lake Okeechobee Basin Research on optimiz ing BMPs for beef cattle ra nching in the Lake Okeechobee basin was initiated in 1996 to reduce nonpoint sources of phosphorus pollution for beef cattle and contribute to modeli ng efforts for load reduction sc enarios. The project is being implemented in several phases, and it is e xpected to be conclude d in 2005. The first phase examines cattle stocking density BMPs. This project was established within the broader context of a Memorandum of Understanding among the SFWMD, Archbold Expeditions’ MacArthur Agro-Ecology Research Center, the IFAS, and the Florid a Cattleman’s Associat ion. The program was established at MacArthur Agro-Ecology Rese arch Center, a 4,170-h ectare cattle ranch operated by Archbold Expeditions in the C-41 ba sin along Harney Pond Canal. In addition to financial support from the SFWMD, the cattle stocking rate project has received funding from Archbold Biologica l Station, the IFAS, the FDEP /USEPA 319 funds, and the United States Department of Agriculture ’s Natural Resources Conservation Service (NRCS) and the National Research Initiative to support a multifaceted project to examine the ecology and economics of sustainable co w-calf operations and control of phosphorus in surface runoff. The most significant finding of the project to date is that surface water phosphorus concentrations and total phosphorus loads were significantly greater from the improved pastures than from the semi -native pastures. Total phosphorus concentrations and loads were five times higher on the improved pastures than on th e semi-native pastures. This difference could be anartifact of prior la nd use history, since th e improved pastures used in the study received phosphorus inputs fo r many years up until 1986. The semi-native pastures, by contrast, were never fertilized. Additionall y, a notable difference was observed in the proportion of ortho-phosphorus in the runoff from the two pasture types. The ratio of ortho-phosphorus to total phos phorus was 0.74 in the improved pastures and 0.23 in the semi-native pastures. The improved pastures not only exported more phosphorus but they also exported a more biologically available form of phosphorus. Soil phosphorus test result s were consistent with the surface water phosphorus data from the pastures. The high phosphorus content in the improved pasture runoff water was matched by correspondingly high water soluble phosphorus concentrations in the improved pasture soils, which were greatest in the upper 5 centimet ers of the soil. Links between soil phosphorus pools and surface water concentrations warrant further investigation. This project is scheduled to continue through 2005. Statistical differences resulting from the different stocking rate s are not expected to be evid ent this early in the project. The stocking density treatments need to be continued for at least two more years before assessing whether the cattle stoc king densities being tested have an appreciable effect on nutrient concentra tions or loads in surface runoff. In addition to continuing the study to obtain statistical differences instocking rates, variability inannual rainfall necessitatesLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

39 that the project be continue d to capture the range of lo ading scenarios likely to be encountered from beef cattle pastures in the basin. 

### E6. Star Grass Experiment Rechcigl et al. (1990) and Re chcigl and Bottcher (1992) showed that fertilization of Bahia grass can c ontribute to phosphorus in runoff because the Bahia grass does not require additional phosphorus. As a result of those studies, which were funded by the SFWMD, the IFAS reduced the phosphorus fert ilization requirement for Bahia grass to zero for South Florida. This was a win- win scenario for the ranchers and Lake Okeechobee. Ranchers will not need to pay for costly phosphorus fe rtilizer that is not needed and less phosphorus is importe d to the Lake Okeechobee watershed. As a follow up to the Bahia grass study, the IFAS suggested that phosphorus fertilization recommendations for other pasture grasses ma y also be reduced. A major field and laboratory experiment was initiated in 1998 to evaluate the optimum phosphorus fertilization requirements for star grass and to evaluate the use of limestone and gypsum soil amendments to reduce the mobility of phosphorus. This study is being conducted by IFAS on the Williamson Ranch in Okeechobee County. Two years of data have been collected from samples of runoff and ground water from field plots and samples of leachate from soil columns inthe laboratory. Preliminary data indicate that both calcium limestone and gypsum may retard phosphorus movement in ground water but not in surf ace water. The initial data also indicate that the phosphorus fertilization recommendations for star grass may be reduce d. Unfortunately, due to the drought conditions in 2000, only two small runoff events occurred.
One field and educational day has been conducted to present the preliminary results of the experiment to the local ranchers. Two more fi eld and educational days are scheduled to be conducted over the next two years. The fina l report is due in September 2002. An IFAS extension publication will also be produced to provide ranchers with the results of the study.


## F. LAKE OKEECHOBEE PROTECTION PROGRAM AND PERMITS
The Florida Legislature passed the Lake Okeechobee Protection Program, amending Section 373.4595(3), F.S., during th e 2000 session. This law establishes a comprehensive long-term program to rest ore and protect Lake Okeechobee and its downstream receiving waters. The legislature also appropr iated $38.5 million dollars to expedite the restoration of Lake Okeechobe e. It requires signifi cant involvement and cooperation between the FDEP, the FDACS, the SFWMD, the IFAS , and the NRCS to implement the program. The legislation is simi lar in scope and approach to the Everglades Forever Act, involving major new programs in planning, construction of major public treatment projects, and new BMP and permitting requirements, though it does not include40 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
dedicated funding. It establishes the Lake Okeechobee Protection Pr ogram and authorizes Lake Okeechobee Protection Pe rmits (Section 373.4595(4), F.S.).


### F1. Overview of the Lake Oke echobee Protection Program The Lake Okeechobee Protection Prog ram contains several components:

Lake Okeechobee Protection Plan. By January 1, 2004, the SFWMD, in cooperation with the FDEP and the FDACS, is to co mplete the Lake Okeechobee Protection Plan. This plan will determine howwater quality standard s, particularly for phosphorus, will be met in Lake Okeechobee and its downstream r eceiving waters. The plan include a combination of source controls (e.g., BMPs) and treatme nt facilities that will be constructed by the District and its partners. It may also determine how sediments within the lake will be mana ged. The components of this pl an are discussed later in this chapter. Lake Okeechobee Watershed Phosphorus Control Program. The Lake Okeechobee Watershed Phosphorus Control Pr ogram includes both agricultural and nonagricultural BMP projects. In February 2001, the FDEP, the FDACS, and the SFWMD entered into an interagency agreement to address how to implement the programs and coordinate with existing re gulatory programs (e.g., WOD a nd Everglades restoration programs). According to the ag reement, the FDACS will be responsible for establishing BMPs for agriculture. If water quality probl ems persist on farms where BMPs have been implemented, the FDACS shall reevaluate the BMPs and make appropriate changes to the rule to adopt additional BMPs. Developm ent of nonagricultural nonpoint source BMPs will be the responsibility of the FDEP. The FDEP shall initially focus on the priority basins, and will deal with a ppropriate nutrient applications rates for soil amendments, monitoring to assess the eff ectiveness of BMPs including domestic wastewater systems, land application of animal residuals, and alternative nutrient reduction technologies. Lake Okeechobee Construction Project. The Lake Okeechobee Construction Project will be implemented in two phases . In Phase 1, a series of projects will be constructed that are focused in the priori ty basins (S-191, S-154, S-65D, and S-65E) and are consistent with the Lake Okeechobee Issue Team’s Ac tion Plan (Harvey and Havens 1999). These include construction of two pilot STAs and the re storation of se veral isolated wetlands as part of the Lake Okeechobee Crit ical Project, a join t program between the SFWMD and the USACE, a sediment removal pilot project in a tr ibutary draining into Lake Okeechobee, and design wo rk on a large-scale STA in the S-191 basin. In Phase 2, the District, in cooperation wi th the other agencies, will develop an impl ementation plan for the construction of a dditional facilities to furt her reduce phosphorus loading throughout the watershed.

Lake Okeechobee Research and Wa ter Quality Monitoring Program. The SFWMD, in cooperation with the FDEP and th e FDACS, is to complete an extensive research and monitoring program that will provide the nece ssary information for the Lake Okeechobee Protection Plan. A water quality baseline fo r total phosphorus will beLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

41 conducted to record existin g conditions. Monitoring will be conducted for long-term ecological changes and for comp liance with water quality st andards. Other specifically identified components include 1) devel opment of a Lake Ok eechobee water quality model, 2) determination of phosphorus sources wi thin the watershed, 3) assessment of phosphorus sources from the Upper Kissimm ee Chain-of-Lakes and Lake Istokpoga, 4) assessment of water management practices within the wa tershed, and 5) ev aluation of the feasibility of alternative nut rient reduction technologies. Exotic Species Control Plan. The District, with coope ration from the FDEP and the FDACS, has identified the exotic speci es within the Lake Okeechobee watershed. The Exotic Species Control Plan was developed to protect the native flor a and fauna from the invasion of exotic species.

Lake Okeechobee Internal Phos phorus Management Program. By July 1, 2003, the District, in cooperation with the FDEP and the FDACS, is to complete a feasibility study to determine it if is reasonabl e to manage phosphorus -laden sediments in the lake. If feasible, the Dist rict will establish the Lake Okeechobee Internal Phosphorus Management Program. Through th is program the District wi ll pursue the design, funding, and permitting for implementing sediment management methods. Annual Progress Report. The District is to submit an annual progress report on the implementation of the La ke Okeechobee Protection Pr ogram to the Governor of Florida and the Florida Legislature. The s econd one will be subm itted on January 1, 2002.


### F2. Overview of the Lake O keechobee Protection Permits

The Lake Okeechobee Protection Perm its contains several components: Existing Structures. All structures discharging in to Lake Okeechobee are to have an FDEP permit, and discharges from the SFW MD structures are to achieve state water quality standards by January 1, 2015. The SFWMD is not to divert waters to the St. Lucie River, Caloosahatchee River, or the Everglad es, in such a way th at state water quality standards are violated, unless the SFWMD de clares an emergenc y and FDEP concurs (existing law retained). Lake Okeechobee Construction Project Facilities. The SFWMD is to obtain permits from the FDEP for the Lake Okee chobee Construction Pr oject. The design objective is to meet the 40 ppb target for phosphorus by 2015, unless the TMDL for the water body is different.


### F3. Lake Okeechobee Watershed Phosphorus Control Program Several projects are be ing conducted within the Lake Okeechobee Watershed Phosphorus Control Program. They include the previously mentioned star grass experiment to determine the appropriate application rates for soil amendments; a study on the land application of residual s and chicken manure; a project to identify, select, monitor,42 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
and implement best availabl e technologies (BATs) for da iries; isolated wetland restoration; and the Phosphorus Source Control Grant Program. F3a. Land Application of R esiduals and Chicken Manure Although dairy farming and beef cattle ranching are often cited as the main source of phosphorus input to the lake , the contribution fr om other sources out side the watershed, such as the land application of sewage sludge (residuals) and chicken manure, also contribute phosphorus to the lake. In Florida, 66 percent of the residuals are applied to land (FDEP, 1997). In 1998, residuals and ch icken manure contributed 1,259 dry tons of phosphorus loading to the Lake Ok eechobee watershed (FDEP, 1999).
Beneficial use of residuals and chicken manure vi a land applicati on is usually limited by nitrogen cons iderations. Customarily, residuals application rates are based on nitrogen needs of the crop. This practice ofte n results in phosphorus inputs that far exceed the amounts required for norma l growth. Addition of phospho rus beyond plant utilization is a waste of a nutrient resource, and in areas of sandy soils, could pose an environmental liability. To reduce phosphorus runoff, the FD EP has initiated a phosphorus rule in the basin, limiting residual applicat ion to the phosphorus requirem ent of the crop versus the nitrogen requirement. Soils in the Lake Okeechobee watershed present a unique situation for management of phosphorus in applied wastes due to a fluctua ting water table and predominantly sandy soils with low phosphor us retention capacity. These conditions promote transport of phosphorus via surface runoff and subs urface lateral seepage to streams and canals, which can lead to eutrophication of surface waters. Water treatment residuals containing al uminum are frequently disposed in landfills. During land applicat ion, addition of aluminum to wastewater residuals and chicken manure may bind exces s phosphorus, thereby minimizi ng the threat to surface waters. The Lake Okeechobee Action Plan (H arvey and Havens, 1999) recommends enhanced source control as a factor in evaluation of th e watershed phosphorus loading issue. In addition, the Lake Okeechobee Protection Act (Sectio n 373.4595, F.S.) requires entities within the Lake Okeechobee wate rshed to develop cons ervation or nutrient management plans that limi t domestic wastewater resi dual application, based upon phosphorus loading. In support of these directives , the District and the FDEP initiated a project that will help ensure that associated nutrient management plans are based on sound science. The results from this study will identify any environmenta l and health problems associated with use of residuals and chicken manure in the wate rshed. Results will include recommendations regarding judi cious applications of resi duals and chicken manure and their establishment as a BMP fo r landowners in the watershed. At the time of this writing, the laboratory characterization of the waste materi als and construction of the field study isLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

43 currently under way. Monitori ng activities are scheduled to commence in 2002. The final report is due by the end of 2003. F3b. Dairy Best A vailable Technologies In the previous Lake Okeechobee SWIM Plan (1997) it was noted that numerous dairies have runoff with to tal phosphorus concentrations in excess of 1,000 ppb, and that current monitoring data show some sites have concentrations above 7,000 ppb. At the present time, many of the 20 active dairies within th e priority basins have phosphorus discharge concentrations in excess of the 1,200 ppb limit identified in the WOD Program (Chapter 40E-61, F.A.C.). Given the current le vel of water quality in the runoff from the Lake Okeechobee watershed, a comprehensive project is be ing undertaken to identify, select, and implement best av ailable technologies (BATs) th at will significantly reduce the export of phosphorus from dairy operations into tributaries and Lake Okeechobee. The objectives of this project will be to identify, sele ct, monitor, and implement BATs that will significantly reduce the e xport of phosphorus from dairy operations into Lake Okeechobee and its tributaries. Various al ternatives will be evaluated to determine the best comprehensive system of technologie s that will address th e multiple dairy farm components (HIAs, waste management system, pastures, etc.). Selection of technologies for implementation will be accomplished by an objective methodology that allows for review and input by a multiage ncy team composed of the FDEP, the FDACs, the NRCS, the SFWMD, and stakeholders. Th is project will address, at a minimum, the following issues: • Engineering feasibility of proposed alternatives • Short- and long-term costs (e.g., cap ital, start-up, cost per kilograms phosphorus removed, operation and ma intenance) including potential revenue sources to of fset project costs • Feasibility of each alte rnative relative to obt aining a water quality goal of 40 ppb (Note that a numeric goal is necessary for the comparison of alternatives. A goal of 40 ppb has been selected for this project based on the most recent re gulatory requirements fo r the watershed and to reduce the harmful ecological imp acts to the lake and downstream regional water resources. If this goal is not attainable, the selected consultant will identify the le vel of phosphorus reduction that is technically and economically practicable.) • Process start-up time and a time line to achieve desired treatment goals • Socioeconomic implications (i .e., economic impacts, cultural resources, social benefi t/cost factors, etc.) • Legal and permitting issues • Coordination with other agencies to avoid duplication of efforts • Opportunities for partnerships with the private sector44 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
It is recognized that in a comprehensiv e approach to reduc ing phosphorus export from dairies, different scenarios may be required for individual dairy phosphorus reduction plans. For example, one dairy’s phosphorus export problem may be primarily due to limitations in its existing waste management system, while another dairy’s problems may have aris en as a result of residual phosphorus accumulation in its outer pasture areas. Phosphorus reduct ion might be accomplished on ea ch of these dairies using different technologies or co mbinations of those techno logies. For this reason, a comprehensive nutrient management plan is be ing developed for each of the three dairies participating in this project prior to selecting appropria te technologies. Each dairy phosphorus reduction scenario is likely to affect project costs, the nature and magnitude of phosphorus export, and/or othe r important considerations. A specific set of goals and performance measures for eachof the alternatives have been developed through this project. Each technology will be evaluated against the performance measures to iden tify all feasible alternatives for reducing phosphorus exports from the dairies. All of the potential impacts (environmental, socioeconomic, etc.) of each alternative will also be identified. Information regarding the technologies that are selected for implementation on the three dairies participat ing in this project wi ll be disseminated to the other dairies and ranches in the watershe d. The assessment phase of the project was completed in 2001. The Governing Board ap proved the project proceeding into the implementation phase. Installation of a water quality monitori ng network has been initiated and design and construction of the technology will follow thereafter.
F3c. Lake Okeechobee Wate r Retention/Phosphorus Removal Critical Restoration Project In 1996, the South Florida Ecosystem Restoration Work ing Group initiated critical restoration projects to be implemented unde r the USACE’s authority provided in Section 528 of the 1996 Water Reso urces Development Act. In 1998, the USACE and the SFWMD proposed the Lake Okeechobee Water Retention/Phosphorus Removal Critical Restoration Project to the working group. Th e working group ranked this project number ten on the list of critical re storation projects. A cooperation agreement for this project was signed on January 7, 2000. The project wa s estimated to cost $16,360,000. The SFWMD is the local sponsor of the proj ect, which will be cost shared between with the USACE and the SFWMD. The initial vision of this project was to increase regional water storage north of Lake Okeechobee through wetland restorati on/creation on lands vo lunteered by private landowners. Approximately 45 per cent of the wetlands in th e Lake Okeechobee watershed have been ditched in order to speed thei r drainage. By simply plugging the drainage outlets, the surface runoff woul d still drain as usual, but the wetlands would once again serve as on-site water storage areas. The se condary and tertiary benefits would include reducing phosphorus in surface runoff and enhancing wildlife habitat, respectively. The proposed project sites are locate d throughout the northern Lake Okeechobee watershed in the following basins: S-65D and S-84, along the Lo wer Kissimmee River; S-154, and Taylor Creek/Nubbin Slough (S-191). Initially tw o pilot STAs and 10 small-Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

45 scale restoration/ creation pr ojects were planned. Those numbe rs are subject to change. An expanded effort for this critical project is being considered thatwould include all Lake Okeechobee subbasins in the north ern part of the watershed th at are contributing nutrients and other pollutants to the lake.
The first STA is located on Taylor Creek. It is a 193-acr e site that was acquired from Grassy Island Ranch. Th e District, in conjunction wi th the USGS is conducting preconstruction monitoring that to determine th e efficacy of the STA. This monitoring will continue after construction is complete. A second STA, approximately 1,000 acres in size, will be constructed adjacent to Nubbin Sl ough at the New Palm/New comer Dairy property acquired by the District through the Save Ou r Rivers Program. The USACE is designing and will construct both STAs. For the small-scale sites, the SFWMD is designing and cons tructing modifications to improve stormwater retent ion, restore wetlands, and im prove quality of discharge water. Components of the proposed modifica tions include plugging drainage ditches and installation of riser culverts in existing drai nage ditches to retain water in currently overdrained historic wetlands . Some of the sites involve expansion of existing water storage ponds or creation of new impoundments. The sites will remain in private ownership and proposed proj ect areas will require fl owage easements with the landowners.
F3d. Isolated Wetland Rest oration and Creation Program Historically, isolated wetla nds covered a significant pe rcent of land area in the Lake Okeechobee watershed, capturing stormwater runoff and helping to retain phosphorus in the watershed. However, in the 1960s, many of these wetlands were drained to put more land into agricultural producti on, and in the proces s, have allowed more phosphorus to reach Lake Okeechobe e. As a consequence, the elimination of wetlands has contributed to the accelerated eutrophication of Lake Okeechobee.
Restoration of ditched natura l wetlands and the creation of new wetlands as filter marshes is one of the poten tial mechanisms for reduci ng phosphorus loading to Lake Okeechobee. One of the programs currently unde r way to restore an d create new wetlands in the Lake Okeechobee watershed is the Lake Okeechobee Isolated Wetland Restoration and Creation Program.
The Lake Okeechobee Isolated Wetland Re storation and Creation Program is a voluntary landowner cost-shari ng program that will be conducted from October 2000 to September 2003. This program offers landowne rs the opportunity to restore isolated wetlands that have previouslybeen ditched, drained, and conve rted to agricultural uses. The SFWMD is administering the program with the cooperation of a multiagency team that includes the FDACs, the FDEP, the NRCS , the USFWS, and the IFAS. As of April 2002, eleven landowners had signed up for th e program and design and construction had begun on two of the sites.46 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
F3e. Phosphorus Source Control Grant Program The goal of the Lake Okeechobee Phosphorus Source Control Gr ant Program is to identify, fund, and implemen t projects that reduce extern al phosphorus loads from the Lake Okeechobee watershed. The SFWMD is administering the program, but an interagency team that includes the FDEP, th e FDAC, the NRCS, and the IFAS participated in the program coordination and selection of projects. The program has two major components: 1) grant and 2) engineering oversight. The grant component is comp rised of two separate f unding releases and will be administered in four phases: 1) Project Selection 2) Implementation and Reporting, 3) Operation and Maintenance, and 4) Monitoring and Repor ting. Under the engineering oversight component, the District will contract an engineering firm to verify that implementation of funded project s is performed in accordance with the funding agreement and grant application. The pr oject selection phase has b een completed for both funding releases. 

### F4. Lake Okeechobee Tributary Sediment Removal Demonstration Project In 1997, the District spon sored a study to determine the relative magnitude of phosphorus content and transport potential of sediment from various tributaries in the northern portion of the Lake Okeechobee waters hed that convey stormw ater runoff to the lake and to analyze feasible management alte rnatives for source rem oval and control. That study, completed by Mock Roos and Associates (1997) concluded thatsediment removal would reduce phosphorus loads to Lake Ok eechobee. The total phosphorus reduction will be limited by a fraction of particulate phosphor us in the tributary bed load, which is about 25 percent. It was estimated between 5 to 25 percent of the particulate phosphorus entering the lake could be eliminat ed by direct sediment removal. The Lake Okeechobee Tributary Sediment Removal Demonstr ation Project was developed in 1999 and is ongoing. It is a multi phase project. Project design and permitting has been completed and constr uction has begun. The project wi ll be completed by October 1, 2003. The project has been designed to de monstrate the phosphorus reduction benefits realized by tributary sediment removal. Before expanding sediment removal to other tributaries, this activity must be demonstrat ed to be technically feasible and economically viable. If the project demonstrat es that either of the tested technologies can successfully trap sediments, the technology wi ll be utilized in other tri butaries by the District and/or private property owners. Th e specific objectives of the study are as follows: • To determine if particulate phos phorus loading to Lake Okeechobee from the Lettuce Creek drainage ba sin may be reduced using either of two sediment removal technologiesLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

47 • To demonstrate the feasibility of se diment removal in a tributary as a method to reduce phosphorus loading to the lake • To perform a detailed assessmentof effectiveness of these two technologies and their economic viability The two sediment removal technologies that will be tested in this demonstration project are a continuous defl ective separation (CDS) unit and a tributary sediment trap (TST). They were selected ba sed on the following criteria: • According to current literature, these technologies are effective in reducing particulat e phosphorus loading. • These technologies can be applied in open cha nnel flow condition and have a high treatment capacity. • These technologies are on the lower e nd of cost for treatment facilities. • The treatment facilities can be easily maintained. The CDS unit is a patented process for removal of beddi ng and suspended solids. It was developed in Australia by CDS Technologies, Ltd., and is manufactured in the United States by CDS Technologies, Inc. The CDS unit works by trapping pollutants using a separation screen. Stormw ater runoff discharges into the center chamber of the CDS unit and then passes through a separa tion screen to an outer chamber prior to discharging downstream. Gross pollutants are trapped ina sump area located below the separation
screen. The use of a tributary sediment trap (TST) is recommended by the Guidebook of Sediment Control Best Management Practices (SFWMD, 1999a). The principle of sediment removal using a sedime nt trap is similar to a sett ling basin/water detention area. An artificial or natural water detention ar ea in which water flow velocities are lowered, relative to inflows, to facilitate the settling of suspended solid s. However, a trap contains a deepened section in addition to a widened section. Water velociti es are suddenly slowed down by a porous barrier or baffle in a settling basin/trap, which allows sediment to settle into a collection area. The project is being conducte d at the site wh ere Lettuce Creek di scharges to the SFWMD conveyance system. Lettu ce Creek is within the Nu bbins Slough basin, which is located northeast of Lake Okeechobee. It di scharges through the L-63S Canal and is one of the major sources of phosp horus load discharging into Lake Okeechobee. Lettuce Creek was selected for this sediment removal demonstrati on because it has the following characteristics: • Continuous flow • No upstream water control structures • Relatively high sediment phosphor us content and particulate phosphorus concentrations • Erosive soil48 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
• Relatively high sediment transport rate • Diversified land uses in the drainage basin • High period of record and 12- month rolling average phosphorus concentration among the tr ibutaries according to the data reported in the Tributary Water Quality Monthly Report

. • Both a CDS unit and a TST will be installed at the discharge site of Lettuce Creek. By instal ling both the CDS unit and the TST at one site, their performance on phosphorus removal can be compared. The project will be conducte d in three phases. Phase I includes the development of a work plan, land surveys, data collection a nd computation for engineering design, project engineering design, development of a quali ty assurance project plan, and project permitting. During Phase II, the CDS unit and the TST will both be constructed and installed, and monitoring instru ments will be calibrated. InPhase III, the monitoring network implemented in Phase II will be operated and maintain ed for 12 months.
After 12 months of monitori ng, the selected contractor will analyze monitoring data to determine whether either sediment removal technology should be applied to other tributaries. Data from th e monitoring network will provide an understanding of phosphorus movement through the tributary sy stem and sediment removal mechanisms. The total cost of construction, maintenance fees, and cost per uni t phosphorus removal of each technology will be analyzed to determin e if these technologies are technically and economically effective and which tec hnology is the most cost-effective. 

### F5. Natural Resource Analys is of Lake Okeechobee Phosphorus Management Strategies The Lake Okeechobee Protection Act ( 373.4595, F.S.) establishes extensive and comprehensive requirements for surface wa ter improvements and management within Lake Okeechobee and its watershed. Cost -effectiveness in re ducing phosphorus is an implicit part of the overall le gislation, and it is e xplicitly referred to in various activities. This project will provide the framework and detailed inform ation for comparing the costeffectiveness of various pho sphorus reduction treatments. The purpose of this project is to provide anenvironmental (o r natural resource) economic analysis of the alternative phosphorus management strategies that have been used, or are being considered, in the La ke Okeechobee watershed. Natural resources valuation principles will be utilized and will include the determination of the economic impacts to the surrounding communities that each of the strategies could present. Alternative phosphorus manageme nt strategies (beyond the Da iry Rule BMPs) are being examined to further reduce external nutrient loads to the lake in an effort to achieve the inlake target phosphorus concentr ation of 40 ppb. Some of th e phosphorus control strategies currently under consideration, or partially implemented, in clude implementation of the Dairy Rule, WOD regulation of nondairy land uses, confinemen t dairies, land acquisition with restrictions, reservoir-assisted STAs , implementation of BATs, implementation ofLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

49 enhanced BMPs, implementati on of projects under the Phosp horus Source Control Grant Program, reclamation or creat ion of isolated wetlands to capture phosphorus and attenuate flows, use of residual and an imal manure from outside the basin, removal of sediments in tributaries, and regiona l treatment systems. Hazen and Sawyer Consultants (1995) determined the direct economic impacts to Okeechobee County and the region from the implementation of the Lake Okeechobee water quality programs that in cluded the Dairy Rule, the Da iry Buy-Out Program, and the WOD Program. The Dairy Rule pr ovides for the collection, stor age, and land application of waste and nutrient-laden runoff HIAs surrounding and including the milking barns. However, the positive impacts from improved water quality conditions of Lake Okeechobee due to the water qua lity programs, such as increased sales, income, and employment related to Okeechobee’s touris m industry, were not included in their economic impact evaluation. During the 1988 to 1993 study period analyzed by Hazen and Sawyer Consultant s (1995), many of the dairies and landowners were constructing the production modifications needed to comply wi th the water quality programs, while other dairies were ceasing operation under the Dairy Buy-Out Program. Because the requirements under the water quality programs were not fully implemented until 1993, the full potential of the expected reductions in phosphorus loads into Lake Okeechobee did not take place until after the study period. This curr ent project will c ontinue where the efforts ended in the 1995 analysis, and will now include a full cost accounting of ten phosphorus control alternatives (PCAs) to further reduce the amount of phosphorus entering Lake Okeechobee.
The PCAs were chosen based on three criteria: • Sufficient information is or will be available to allow for an adequate evaluation of benefits and co sts associated with the PCA. • The PCAs have the potential to su ccessfully reduce phosphorus loading to Lake Okeechobee. • The PCAs are being consid ered in planning programs.
Benefits and costs of each alternative to the District, to landowners, and to the regional economy will be described and qua ntified. The following PCAs were selected according to th e above criteria: 1. Chemical treatment of runoff at the edge of property 2. Wetland treatment of runof f at the edge of property 3. Nonstructural management at the land parcel level 4. Optimization of Dairy Rule desi gn or use of alternative waste management technologies 5. Enhanced cow-calf BMPs 6. Alternative land uses – convert da iry, citrus, field crop, and row crops to land uses such as wetlands, na tural areas, cow-calf operations, and forage production50 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

7. Reservoir-assisted STAs 8. System able to receive supplemental water from the lake 9. Tributary sediment removal 10. Terminal large-scale wa ter treatment facilities This study will identify benefits and cost s of each PCA using a full cost accounting approach, which attempts to id entify and quantify the social benefits and costs resulting from a policy decision. Decades of research into phosphorus reduction strategies in the Lake Okeechobee Basin and the EAA, and ma ny current and new re search and planning projects, will provide a wealth of data that may be used to provide an economic evaluation of alternatives.
The benefits and costs of the PCAs wi ll be measured relative to baseline conditions that represent current management practices of landowners , to the extent that the available information will allow. This study will also consider the costs per unit of phosphorus reduction associated with a range of phosphorus input and output levels for those PCAs that can be effectivel y implemented at different scales. A Computerized Alternatives Evaluati on/Full Cost Accounting Model will be developed to allow for updati ng as new data and informat ion become available. The benefit-cost analysis w ill be used in conjunction with a model that uses evaluation criteria to measure the relative benefi ts and costs of the alternativ e and will provide a ranking of alternatives based on th e magnitude of it emized benefits and costs. This will allow the District to add and evaluate additional PCAs in the future. 

## K. CLASS I, III, AND IV STANDARDS
Historical (1988 to 2000) tr ibutary inflow water qualitydata were evaluated to determine the level of compliance with numer ic state water qualitystandards (Chapter 62-302.530, F.A.C.). Sample locations included 33 tributary stat ions located at all water control structures maintained by the SFW MD and the USACE; locations along the Kissimmee River, Taylor Cree k/Nubbins Slough, Harney Pond and Indian Prairie canals, and Fisheating Creek; and all Everglades Protection District structures that drain into the lake through pump stations or culverts including the f our Chapter 298 Districts and Closter Farms ( Figure 2-3 ). In addition, in 1992, more than 60 previously unsampled water quality and biological parameters were collected during a 12-month monitoring program at the same 42 stations mentioned above (Ogburn et al., 1996). The classification of tributary waters varies. For example, S308C and S77 waters must meet Class I (potable wate r supplies) criteria no matter if they are flowing into the lake or not. CULV10 and CULV10A waters fl owing into the lake must meet Class I standards, but if water is not flowing into the lake, the water needs to meet only Class IV and Class III standards, respectively. Indus trial Canal must meet Class III standards whether water is flowing into the lake or not. The observati ons were thus separated into inflow ( Table 2-4 ) or no inflow ( Table 2-5 ) to the lake, and th en subdivided by theLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

51 Figure 2-3. The tributary stations samples were collected from to determine compliance with Class I, III, and IV Standards52 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

standards that each station must meet. Ob servations for each class parameter were summed to determine the overall percent nonc ompliance for each given parameter.
All values for each contaminant were summ ed and the percentage of instances that the criterion was exceeded was calculated for each class. Anevaluation of these data from the 13-year period of 1988 to 2000 indicated that major in flows generally comply with applicable state water quality criteria with the ex ception of dissolved oxygen, iron, and conductivity ( Table 2-4 ). Water quality criteria for mo st monitored parameters were exceeded in less than 25 percent of the measurements at specif ic locations. The criteria for arsenic, trace metals (cadmium , copper, lead, mercury, and zinc) and organic contaminants were rarely exceeded in the lake inflows. Fo r most tributaries, fewer than 20 trace metal samples were taken over the 13-year period wh ile waters were flowing into the lake. Due to this small sample size, the percentage of instances that criter ion was exceeded was not calculated for these contaminants. Based on the number of time s the criteria were exceeded, water quality associated with in flows has not substantively impaired the designated uses of the lake. However, additional monitoring of biological conditions and trace metals during inflow conditions may be warranted to document whether the inflows meet their designated use. Parameters that widely or frequently exceeded the criteria included alkalinity, chloride, dissolved oxygen, cond uctivity, and iron. Pesticide criteria were infrequently exceeded during the quarterly sampling in the supplemental moni toring program (Ogburn et al., 1996), but pesticides and other organics are included in this evaluation despite the very limited database, and because of th eir potential for ec ological impacts. 

### K1. pH
The Class I, III, and IV criteria for pH include minimum (6.0) and maximum (8.5) values, unless natural background conditions ar e documented to be lo wer or higher. The criteria were developed primar ily to protect aquatic life. More than 10 percent of the samples at the Fisheating Creek station (FECSR78) exceeded th e criteria during periods of inflow ( Table 2-4 ). These samples had many low pH values, which appeared to be associated with naturally occurring humic and fulvic acids fr om wetlands in the Fisheating Creek drainage basin. 

### K2. Alkalinity The criteria for alkalinity require a minimum value of 20 ppm as calcium carbonate (CaCO 3 ) for Class I and III waters, whil e no minimum and a maximum of 600 ppm is required for Class IV waters. Alkalin ity buffers pH changes, and the bicarbonate and carbonate that contribute to alkalinity can complex some trace metals and reduce their potential toxicity to aquatic organisms. Low alkalinity can inhibit shell formation by aquatic snails and other mollusks.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

53 Table 2-4. The percentage of instances that Class I and III criteria was exceeded for tributary samples taken during inflow periods to Lake Okeechobee a

STATIONpHAlkalinityConductivityChlorideDissolved OxygenTotal Dissolved SolidsTurbidityUn-ionized AmmoniaNitrateIronArsenicCadmiumCopperLeadZincMercury

Class I CULV10 0.0 2.0 74.5 52.1 84.8 ND 22.9 33.3 2.2 ND ND ND ND ND ND ND 45 49 47 48 46 7 48 48 45 12 12 11 11 11 11 11 CULV10A 3.5 2.2 19.5 11.1 89.4 ND 3.4 7.0 0.0 65.4 0.0 0.0 0.0 0.0 0.0 0.0 86 90 87 90 85 17 89 86 87 26 26 24 23 24 24 23 CULV12 0.0 2.8 34.3 11.1 82.4 ND 5.6 13.9 5.6 ND ND ND ND ND ND ND 34 36 35 36 34 7 36 36 36 10 10 9 9 9 9 10 CULV12A 1.0 0.0 86.1 80.6 86.9 ND 1.9 16.3 0.0 19.2 0.0 4.0 0.0 0.0 0.0 0.0 101 103 101 103 99 17 104 104 97 26 26 25 25 25 25 25 CULV4A 0.0 1.6 71.2 9.7 96.6 ND 1.7 13.6 1.9 ND ND ND ND ND ND ND 59 61 59 62 59 6 60 59 54 9 9 8 8 8 8 10 CULV5 ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND 12 14 13 14 12 2 14 14 14 4 4 4 4 4 4 4 FECSR78 15.8 72.1 23.4 0.0 55.2 0.0 0.0 1.1 0.0 91.1 0.0 7.1 0.0 11.9 2.4 0.0 183 190 184 189 181 27 186 189 172 45 44 42 42 42 42 41 HGS5 ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND 2 3 2 3 21 3 3 31111111 S127 0.0 0.0 11.9 14.9 65.7 ND 0.0 1.5 0.0 ND ND ND ND ND ND ND 67 68 67 67 67 10 67 67 63 15 15 13 13 13 13 15 S129 0.0 0.0 0.0 0.0 50.0 ND 0.0 1.9 0.0 ND ND ND ND ND ND ND 50 53 50 53 48 7 53 52 45 11 11 10 10 10 10 11 S131 1.9 0.0 0.0 0.0 51.9 ND 0.0 1.9 0.0 ND ND ND ND ND ND ND 53 55 54 55 52 8 55 53 44 11 11 11 11 11 11 11 S133 0.0 0.0 2.3 0.0 65.9 ND 0.0 0.0 0.0 ND ND ND ND ND ND ND 44 45 44 45 44 7 44 45 45 11 12 12 12 12 12 11
a. The upper number in each cell indicates the number of sample s collected, while the lower number represents the percentage the criterion was exceeded. The key below explains the color coding
25% or more of samples exceed criterion
Between 10% and 25% of samples exceed criterion
Less than 10% of samples exceed criterion

ND Not determined

Criterion has not been established54 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

S135 0.0 2.3 0.0 0.0 38.1 ND 0.0 2.3 0.0 ND ND ND ND ND ND ND 42 43 42 43 42 7 43 43 38 8 8 8 8 8 8 8 S191 2.6 3.4 19.4 1.9 68.5 ND 0.9 4.7 0.0 86.2 0.0 0.0 3.7 0.0 3.6 0.0 386 178 377 376 371 17 212 403 397 29 29 28 27 28 28 28 S2 0.0 2.3 31.6 0.0 98.2 ND 15.2 15.2 0.0 ND ND ND ND ND ND ND 57 43 57 48 56 7 46 66 52 9 9 9 9 9 9 7 S236 0.0 0.0 79.2 68.0 87.5 ND 3.8 11.5 0.0 ND ND ND ND ND ND ND 24 26 24 25 24 5 26 26 25 7 7 7 7 7 7 7 S3 0.0 0.0 17.1 10.3 100.0 ND 0.0 18.0 0.0 ND ND ND ND ND ND ND 41 24 41 29 41 7 30 50 37 8 8 8 8 8 8 8 S308C 0.0 0.0 2.7 0.0 41.7 ND 8.6 2.8 0.0 ND ND ND ND ND ND ND 36 36 37 36 36 5 35 36 34 9 9 9 9 9 9 9 S4 0.0 4.0 0.0 0.0 70.8 ND 0.0 0.0 0.0 ND ND ND ND ND ND ND 24 25 24 25 24 1 24 24 23 4 4 4 4 4 4 4 S77 ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND 2 2 2 2 20 2 2 20000000 Class I Total 3.3 13.2 27.0 12.3 71.2 44.8 2.7 7.4 0.3 52.9 0.0 1.6 0.4 2.1 0.8 0.0 1,348 1,144 1,347 1,349 1,325 165 1,177 1,406 1,313 255 255 243 241 243 243 244 Class III C38W 4.9 0.0 97.5 43.4 7.8 2.3 0.0 0.0 11.9 0.0 0.0 0.0 0.0 123 130 119 122 129 128 44 44 42 41 42 42 39 INDUSCAN 0.0 0.0 19.0 55.2 5.5 3.5 ND ND ND ND ND ND ND 58 57 58 58 55 57 12 12 10 10 10 10 12 L59E 0.0 9.1 54.5 100.0 0.0 9.5 ND ND ND ND ND ND ND 20 22 22 20 21 21 3333333 Table 2-4. The percentage of instances that Class I and III criteria was exceeded for tributary samples taken during inflow periods to Lake Okeechobee a (continued)

STATIONpHAlkalinityConductivityChlorideDissolved OxygenTotal Dissolved SolidsTurbidityUn-ionized AmmoniaNitrateIronArsenicCadmiumCopperLeadZincMercury

a. The upper number in each cell indicates the number of sample s collected, while the lower number represents the percentage the criterion was exceeded. The key below explains the color coding
25% or more of samples exceed criterion
Between 10% and 25% of samples exceed criterion
Less than 10% of samples exceed criterion

ND Not determined

Criterion has not been establishedLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

55 L59W 4.5 2.6 8.1 65.8 0.0 2.7 0.0 0.0 6.9 0.0 0.0 0.0 0.0 111 115 111 111 113 111 31 31 29 28 29 29 31 L60E 5.0 4.8 8.0 56.6 0.0 1.0 3.6 0.0 3.7 0.0 0.0 0.0 0.0 101 104 100 99 103 101 28 28 27 26 27 27 25 L60W 3.4 0.0 5.2 64.9 0.0 1.7 ND ND ND ND ND ND ND 58 60 58 57 59 58 16 16 13 13 14 13 13 L61E ND ND ND ND ND ND ND ND ND ND ND ND ND 16 16 16 16 16 16 7666666 L61W 4.7 1.5 18.8 82.8 0.0 1.6 14.3 0.0 ND ND ND ND ND 64 65 64 64 63 63 21 21 19 19 19 19 19 S154 2.8 5.2 21.4 69.4 0.0 5.1 ND ND ND ND ND ND ND 181 96 173 173 109 196 15 15 14 14 14 14 14 S154C 1.7 0.0 96.7 77.3 0.0 2.2 2.8 0.0 2.9 0.0 0.0 0.0 0.0 180 188 182 181 188 183 36 35 34 34 34 34 33 S65E 5.2 10.7 1.5 39.4 0.0 3.4 1.4 0.0 3.6 1.8 5.5 0.0 0.0 542 366 521 520 431 590 281 59 55 55 55 55 56 S71 4.6 14.5 9.0 69.5 0.0 4.9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 174 186 177 174 184 182 34 34 32 32 32 32 29 S72 0.0 4.9 13.8 82.3 0.0 2.5 ND ND ND ND ND ND ND 80 82 80 79 79 80 19 19 18 18 18 18 18 S84 4.1 36.2 12.2 26.7 0.0 3.1 0.0 0.0 14.8 3.7 14.8 0.0 0.0 271 138 270 270 135 293 29 29 27 27 27 27 27 Class III Total 3.9 8.4 23.2 54.1 0.8 3.2 3.8 0.0 4.9 0.6 2.7 0.3 0.0 1,979 1,625 1,951 1,944 1,685 2,079 576 352 329 326 330 329 325 Table 2-4. The percentage of instances that Class I and III criteria was exceeded for tributary samples taken during inflow periods to Lake Okeechobee a (continued)

STATIONpHAlkalinityConductivityChlorideDissolved OxygenTotal Dissolved SolidsTurbidityUn-ionized AmmoniaNitrateIronArsenicCadmiumCopperLeadZincMercury

a. The upper number in each cell indicates the number of sample s collected, while the lower number represents the percentage the criterion was exceeded. The key below explains the color coding
25% or more of samples exceed criterion
Between 10% and 25% of samples exceed criterion
Less than 10% of samples exceed criterion

ND Not determined

Criterion has not been established56 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Table 2-5. The percentage of instances that the Class I, III, and IV criteria was exce eded for tributary samples taken during periods of no inflow to Lake Okeechobee b

STATIONpHAlkalinityConductivityChlorideDissolved OxygenTotal Dissolved SolidsTurbidityUn-ionized AmmoniaNitrateIronArsenicCadmiumCopperLeadZincMercury

Class I S308C 3.8 0.6 2.5 0.0 12.0 0.0 17.0 0.0 0.0 87.9 0.0 0.0 0.0 9.7 0.0 0.0 158 159 159 158 158 24 159 153 147 33 33 31 30 31 31 31 S77 2.5 3.0 3.0 0.0 44.7 0.0 1.0 2.6 0.0 15.2 0.0 0.0 0.0 0.0 2.2 0.0 200 198 200 200 197 28 200 196 195 46 47 45 45 45 45 44 Total Class I 3.1 2.0 2.8 0.0 30.1 0.0 8.1 1.4 0.0 45.6 0.0 0.0 0.0 3.9 1.3 0.0 358 357 359 358 355 52 359 349 342 79 80 76 75 76 76 75 Class III C38W ND ND ND ND ND ND ND ND ND ND ND ND ND 13 13 10 12 13 13 1111111 CULV10A 1.9 0.0 5.8 25.0 13.5 1.1 38.1 0.0 5.0 0.0 5.0 0.0 ND 104 96 103 104 96 90 21 20 20 20 20 20 17 CULV5 6.5 2.4 19.4 87.0 2.4 0.8 9.8 0.0 5.3 0.0 2.6 0.0 0.0 124 126 124 123 125 125 41 40 38 38 38 38 37 FECSR78 ND ND ND ND ND ND ND ND ND ND ND ND ND 777 7 7 7 4444444 HGS5 2.7 0.5 15.4 28.2 22.3 7.6 28.6 0.0 0.0 0.0 0.0 0.0 0.0 294 221 293 291 220 223 49 48 46 46 46 46 48 INDUSCAN 1.9 0.9 21.0 38.8 0.0 4.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 104 106 105 103 109 109 31 30 30 30 30 30 29 L59E 4.0 0.9 45.6 72.5 1.9 7.4 7.7 0.0 8.1 2.8 0.0 2.7 0.0 101 109 103 102 108 108 39 39 37 36 37 37 35 L59W 0.0 1.9 12.5 46.8 0.0 5.7 ND ND ND ND ND ND ND 48 53 48 47 52 53 14 14 14 14 14 14 14 L60E 3.6 1.7 8.8 48.2 0.0 0.0 ND ND ND ND ND ND ND 55 60 57 56 60 59 19 19 18 18 18 18 18 b. The upper number in each cell indicates the number of sample s collected, while the lower number represents the percentage the criterion was exceeded. The key below explains the color coding
25% or more of samples exceed criterion
Between 10% and 25% of samples exceed criterion
Less than 10% of samples exceed criterion

ND Not determined

No criterion has been establishedLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

57 L60W 8.6 7.0 5.3 59.6 0.0 6.0 3.6 0.0 0.0 0.0 3.6 3.6 0.0 93 100 95 94 99 100 28 28 28 28 28 28 25 L61E 2.5 4.7 9.8 50.0 0.8 1.6 0.0 0.0 3.0 0.0 3.0 0.0 0.0 122 128 123 122 126 127 35 35 33 33 33 33 31 L61W 1.5 1.5 4.5 60.6 1.5 1.5 ND ND ND ND ND ND ND 65 67 66 66 67 67 19 18 18 18 18 18 17 S127 3.3 0.8 17.9 38.5 0.8 2.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 122 127 123 122 127 127 34 33 33 32 33 33 29 S129 0.0 0.0 2.6 23.5 0.0 1.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 115 120 116 115 120 121 35 35 34 34 34 34 31 S131 4.0 0.0 0.0 28.8 0.0 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 125 128 125 125 126 128 39 38 36 36 36 36 34 S133 0.0 0.8 1.6 51.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.0 0.0 121 127 122 119 126 124 36 35 33 32 33 33 32 S135 3.2 1.5 0.0 30.6 0.8 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 124 132 126 124 131 130 40 40 38 37 38 38 37 S154 2.2 1.5 22.6 45.3 0.9 3.4 81.3 0.0 6.5 0.0 0.0 0.0 0.0 365 200 350 349 226 387 32 31 31 31 31 31 28 S154C 0.0 0.0 89.5 92.1 0.0 2.4 ND ND ND ND ND ND ND 38 41 38 38 41 41 12 12 11 10 11 11 12 S191 3.3 0.7 24.0 32.4 1.6 3.3 0.0 0.0 0.0 0.0 0.0 5.0 0.0 304 148 296 296 183 337 23 21 20 20 20 20 21 S2 0.6 0.0 31.4 37.1 3.6 8.4 2.4 0.0 0.0 0.0 0.0 0.0 0.0 171 171 172 170 168 166 42 44 42 42 42 42 41 S3 2.8 1.1 30.6 28.2 1.7 4.6 2.3 0.0 2.4 0.0 0.0 0.0 0.0 180 179 180 177 178 175 44 44 42 42 42 42 42 Table 2-5. The percentage of instances that the Class I, III, and IV criteria was exceeded for tributary samples taken during periods of no inflow to Lake Okeechobee b (continued)

STATIONpHAlkalinityConductivityChlorideDissolved OxygenTotal Dissolved SolidsTurbidityUn-ionized AmmoniaNitrateIronArsenicCadmiumCopperLeadZincMercury

b. The upper number in each cell indicates the number of samples collected, while the lower number represents the percentage the criterion was exceeded. The key below explains the color coding
25% or more of samples exceed criterion
Between 10% and 25% of samples exceed criterion
Less than 10% of samples exceed criterion

ND Not determined

No criterion has been established58 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

S4 1.5 0.0 12.5 25.4 0.0 5.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 136 143 136 134 143 141 46 45 43 43 43 43 41 S65E 1.6 1.9 0.0 18.2 0.0 1.3 0.0 ND ND ND ND ND ND 62 52 56 55 66 75 35 4 3 3 3 3 3 S71 5.3 4.1 7.4 45.7 1.0 1.0 ND ND ND ND ND ND ND 94 98 94 94 98 96 15 14 14 14 14 14 14 S72 3.1 4.0 9.3 43.8 0.0 1.0 0.0 0.0 3.4 0.0 3.4 0.0 0.0 96 101 97 96 101 100 30 30 29 28 29 29 28 S84 2.0 18.8 11.1 13.2 0.0 2.9 ND ND ND ND ND ND ND 198 101 199 197 100 208 19 19 19 18 19 19 14 Total Class IIl 2.8 2.0 16.6 39.2 3.0 3.4 7.9 0.0 1.8 0.3 1.0 0.7 0.1 3,381 2,954 3,364 3,338 3,016 3,437 783 741 715 708 715 715 683 Class IV CULV10 1.7 0.0 37.8 34.2 1.6 0.0 0.0 0.0 0.0 0.0 0.0 120 124 119 117 125 37 36 36 36 36 36 CULV12 4.0 0.0 27.2 20.3 0.8 0.0 0.0 0.0 0.0 0.0 0.0 126 134 125 123 132 39 38 38 38 38 37 CULV12A 1.4 0.0 45.1 55.7 1.4 0.0 0.0 0.0 0.0 0.0 ND 71 74 71 70 73 21 20 20 20 20 19 CULV4A 0.0 0.0 23.2 29.7 2.7 0.0 0.0 0.0 0.0 0.0 0.0 112 114 112 111 113 36 35 35 35 35 34 S236 0.8 0.0 61.1 33.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 126 131 126 125 131 39 38 38 38 38 34 Total Class IV 1.6 0.0 38.7 32.8 1.2 0.0 0.0 0.0 0.0 0.0 0.0 555 577 553 546 574 172 167 167 167 167 160 Table 2-5. The percentage of instances that the Class I, III, and IV criteria was exce eded for tributary samples taken during periods of no inflow to Lake Okeechobee b (continued)

STATIONpHAlkalinityConductivityChlorideDissolved OxygenTotal Dissolved SolidsTurbidityUn-ionized AmmoniaNitrateIronArsenicCadmiumCopperLeadZincMercury

b. The upper number in each cell indicates the number of sample s collected, while the lower number represents the percentage the criterion was exceeded. The key below explains the color coding
25% or more of samples exceed criterion
Between 10% and 25% of samples exceed criterion
Less than 10% of samples exceed criterion

ND Not determined

No criterion has been establishedLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

59 During inflow conditions, low alkalinity criteria were exceeded in more than 25 percent of samples at FECSR 78 (Fisheating Creek) and S 84, and were exceeded in more than 10 percent of the sa mples at S65E and S71 ( Table 2-4 ). Low alkalinity values were directly associated with low pH. Low alkalinity appears to be a natural condition in the inflow systems where it was documented. Since al kalinity within the lake very rarely was below the minimum value and no samples exce eded the maximum value, the instances of low alkalinity in these tributaries has not contributed to any degradation of the lake.


### K3. Chloride The Class I chloride criterion (250 ppm) is based on drinking water concerns, as high levels of chloride can gi ve drinking water a salty taste. Class III and IV criteria have not been established for chloride. The chlo ride criterion was not exceeded during no inflow condition ( Table 2-5 ), but was exceeded during in flow conditions more than 25 percent of the time at thr ee stations (CULV10, CULV12A, and S236), and exceeded more than 10 percent of the time at four other stations (CULV10A, CULV12, S127, and S3) ( Table 2-4 ).
Five of the stations withchloride criterion violat ions are located along the southeastern shore of the lake ( Figure 2-3 ). Shallow ground water along the southeastern shore of the lake is affected by chloride and other salts that remain from the Pleistocene Era, when much of Florid a was covered by shallow seas (Schroeder et al., 1954). Therefore, the inflows with hi gh chloride concentr ations appear to be related to ground water seepage into the canals, and they do not appear to impact the use of the lake as a source of drinking water. 

### K4. Dissolved Oxygen Adequate levels of dissolved oxygen are ne cessary for aquatic animals to respire. The Class I and III criteria require a minimum of 5.0 ppm, and the Class IV minimum is 3.0 ppm during inflow conditions. The Class I and III criteria fo r dissolved oxygen were exceeded in more than 25 percent of the samp les in all of the stat ions with 20 or more samples ( Table 2-4 ). During no inflow conditions, the cr iteria were exceeded 25 percent of the time at all but 5 statio ns with 20 or more samples. At these 5 stations, the criteria were exceeded 10 percent of the time. Many of the inflow stations showed a greater tendency for the dissolved oxygen criteria to be exceeded when water was flowi ng toward the lake, as opposed to when water was not flowing towards the lake , especially for stations at the southern end of the lake ( Figure 2-3 and Tables 2-4 and 2-5 ). This may be due to seepage of ground water with low dissolved oxygen concentrations into canals during pumping ev ents. Canal water levels can be drawn down fast er than ground water levels by pumping at control structures causing ground water to seep into the canals. Ground wate r typically has low dissolved oxygen levels that tend to reduce the dissolved oxygen leve ls in the canals. However, no studies have been conducted to document whet her seepage into canals has a significant impact on surface water dissolved oxyge n concentrations during pump events.60 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
Dissolved oxygen fluctuates naturally in water bodies because of many physical and biological factors. The da ta collected on dissolved oxyge n is done on a snapshot basis, and the time of sampling can have an impact on the va lues. Dissolved oxygen values during extended periods of no inflow at a structure can al so play a role. Chronically low dissolved oxygen values can be the result of anthropogenic influences, but they can also be a natural characteristic of wetlands and other low en ergy systems. Schwartz (1985) concluded that the low dissolved oxygen values in Taylor Creek/Nubbins Slough, Fisheating Creek, and the Kissim mee River systems were due to drainage from extensive wetlands systems in their basins. Loading of oxygen-de manding substances and ground water seepage into the drainage systems ar ound the lake also may contribute to the low dissolved oxygen values documen ted in the inflows. In-lake criteria were exceeded less than two percent of the time at all locations ( Table 3-4 in Chapter 3 ), thus they are of no great concern. However, ad ditional monitoring may be needed to determine the significance of the potential causes of low dissolved oxygen before management strategies are evaluated.


### K5. Total Dissolved Solids

The Class I criterion for total dissolved solids is no greater than 500 ppm on a monthly averaged basis or not greater th an 1,000 ppb at any time. No Class III or IV criteria for total dissolved solids have beenestablished. During periods of no inflow, the Class I criterion for total dissolv ed solids was not exceeded ( Table 2-5 ). During periods of inflow to the lake, less than 20 samples were taken for each tributary, with the exception of FECSR78, so the percentage of instances that the criterion was exceeded could not be calculated. However, a summation of all of th e observations show thatthe Class I criterion was exceeded over 45 percent of the time ( Table 2-4 ). Based on this finding it is recommended that the tributaries be sampled on a regular basis for total dissolved solids. 

### K6. Turbidity Turbidity is evaluated with respect to background values. The criterion allows a maximum of 29 nephelometric turbidity units (NTUs) above background. Background turbidity for each station was assumed to be the median (i.e ., 50 percent of the samples are less than and 50 percent of the samples are greater than the median value). More than 10 percent of the samples taken at two stations during inflowconditions (CULV10 and S2) and three other stations during no infl ow conditions (S308C, CULV10A, and HGS5) exceeded the criterion ( Tables 2-4 and 2-5 ). Watershed manageme nt strategies may reduce sediment loading and turbidity levels in canals.


### K7. Un-ionized Ammonia Aqueous ammonia can be pr esent as un-ionized ammoni a and as ammonium ion. Un-ionized ammonia is the form that is toxic to some aquatic organisms. The criterion allows up to 0.02 ppm un-ionized ammonia to be present in the water. The proportion of un-ionized ammonia increases with increa sing pH and temperat ure. The un-ionized ammonia criteria was exceeded at many tri butary stations, but these instances wereLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

61 generally infrequent. During no inflow conditions no station had more than 10 percent of samples exceeding the criterion ( Table 2-5 ). During inflow conditions one station (CULV10) exceeded the criterion in more th an 25 percent of the samples and six stations (CULV12, CULV12A, CULV4A, S 2, S236, and S3) exceeded th e criterion in more than 10 percent of the samples ( Table 2-4 ). These high levels ar e most likely related to anthropogenic sources of nitrogen, such as land spreading of sludge and/or agricultural fertilizers.


### K8. Iron
The Class I, III, and IV standards fo r iron are 0.3, 1.0, and 1.0 ppm, respectively, During inflow periods, only 4 stations that ar e required to meet Cla ss I standards for iron (CULV10A, CULV12A, FECSR78, and S191) ha d been sampled 20 or more times ( Table 2-4 ). CULV12A exceeded the criterion more th an 10 percent of the time while the three others exceeded Class I criterion more than 25 percent of the ti me. Only one station required to meet Class III st andards during inflow periods, L61W, exceeded this standard more than 10 percent if the time ( Table 2-4 ). During no inflow periods, both stations (S3 08C and S77) that are required to meet Class I standards exceeded th e criterion for iron. S308C exc eeded the Class I standard more than 25 percent of the time and S 77 more than ten percent of the time ( Table 2-5 ). Class III standards were exceeded more than 25 percent of the time at three stations: CULV10A, HGS5, and S154. 

### K9. Arsenic and Trace Metals (Cadmium, Copper, Lead, Zinc, and Mercury

The Class I criterion for arsenic is 50 ppb. The Class I criteria for cadmium, copper, lead, and zinc are calculated as a fu nction of water hardness, and, therefore, do not have specific values. The hist orical database generally ha d less than 40 obs ervations each for arsenic, cadmium, copper, lead, mercury, and zinc for each tribut ary for both periods of inflow or no inflow to the lake ( Tables 2-4 and 2-5 ). Because of the small sample size (less than 20), the percentage that the criter ia were exceeded were not determined at a number of tributaries. However, when data for each metal was summed for each class, the number of samples exceeding the criteria for periods of inflow wa s less than 10 percent for both Class I and Cl ass III criteria ( Table 2-4 ). The criteria for arsenic were not exceeded in either class. Most likely, the trace metal criteria is being exceeded due to anthropogenic activities and sources such as agricultural us es of sludge, fertilizers, and pesticides; burning of fossil fuels and wa stes; and gasoline additives. The limited amount of trace metal data makes it difficult to determine if management strategies need to be implemented to reduce trace metal concentrations. The Di strict’s monthly monitoring program should be modified to include trace metals to fa cilitate a more conclusive assessment of the potential n eed for management measures to control trace metals within the tributaries.62 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT 

### K10. Organics and Pesticides

Pesticides and herbicides could be found in inflow samples because of the dominance of agricultural land uses in mu ch of the Lake Ok eechobee basin. During 1993 and 1994, CULV10 was the only loca tion with detectable levels of pesticides (Ogburn et al., 1996). During two quarterly sa mpling events, concentrations of dieldrin and dichlor diphenyl trichlor (DDT) exceeded criteria in samples taken at CULV10. One instance of the toxaphene criteria bein g exceeded was documented at CULV10. At CULV10A, the polycyclic aromatic hydrocarbon criterion (2 -methyl naphthalene) was exceeded once. The results indicated that pesticides and other organic contaminants do not chronically exceed the criter ia. These results ar e also supported by the sediment sampling analysis that showed only dichlor diphenyl dichlor (DDD-p,p') and dichlor diphenyl ethylene (DDE-p,p') were above the detection limit in seven and nine of the 31 samples taken, respectively. For the tributaries, thes e parameters were only sampled four times at each station, and the seasonal application of pesticides a nd variations in transport to surface waters based on rainfa ll patterns could ha ve affected the likelihood of detecting organic contaminants. Therefore, additi onal organic monitoring may be needed in conjunction with the District’s existing mon itoring program to al low conclusions to be made regarding the instances of the criteria being exceeded for pestic ides, herbicides, and other organic contaminants. The list of organic parame ters from the supplemental monitoring program should be reduced to fo cus on compounds that are known to have potential sources in the watershed, such as pesticides, herbicides, and petroleum hydrocarbons. Quarterly sampling for organi cs was recommende d, and the schedule within each quarter should be based on seas onal uses of agricultural chemicals and/or periods of inflow to the lake.


### K11. Coliforms Ogburn et al. (1996) also measured total and fecal coliforms at the tributaries throughout a year and found instances of criteria for both being exceeded ( Table 2-6 ). Of the 87 fecal coliform measurements taken during inflow conditions, 22 were above the criteria. However, only 9 of the 84 measurements of total coliforms we re above the criteria during inflow conditions. It is recommended th at a routine monitori ng for fecal and total coliforms be initiated in the District's monitoring program.


### K12. Recommended Class I and I II Management Strategies for Tributaries Based on existing land uses and water qua lity conditions in the Lake Okeechobee basin, several strategies for ca nals and marinas may be app licable to the lake inflows:

• Canals - Oxygen injection, air inject ion, sediment removal, and constructed wetlands

• Marinas - Liquid waste management and boat maintenance control
measuresLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

63 Table 2-6. Results of fecal and total coliform measuremen ts taken in lake okeechobee tributaries and in-lake stations from October 1993 to September 1994 cd

Station Fecal Coliforms Total Coliforms Inflow No Inflow Inflow No Inflow Class I Class III Class I Class III Class I and III Class I and IIINumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamples

CULV10 2 2

. . . . . .12

. . CULV10A 0 4

. . . .15 0 4 3 5 CULV12 1 2

. . . . . .02

. . CULV12A 4 4

. . . . . .34

. . CULV4A 2 2

. . . . . .12

. . CULV5 . 0

. . . . 1 12 . 0 0 12 FECSR78 16

. . . .16 0 6 1 6 HGS5 1 3 26 0 3 2 6 INDUSCAN

. .34

. .08 0 4 2 8 L001

. . . . 0 12

. . . . 1 12 L002

. . . . 0 12

. . . . 1 12 L003

. . . . 0 12

. . . . 0 12 L004

. . . . 0 12

. . . . 1 12 L005

. . . . 0 12

. . . . 0 12 L006

. . . . 0 12

. . . . 0 12 L007

. . . . 0 12

. . . . 0 12 L59E

. .01

. . 3 11 0 1 2 11 L59W

. . 0 11

. . 0 1 1 10 0 1 L60E

. .16

. .06 1 5 0 6 L60W

. . 1 10

. .02 1 9 0 2 L61E

. . .0

. . 0 12 . 0 2 11 L61W

. . .0

. . 3 12 . 0 0 12 LZ2

. . . . 0 12

. . . . 1 12 LZ30

. . . . 0 12

. . . . 1 12 S127 0 1

. . . . 0 11 0 1 1 11 S129 1 2

. . . . 0 10 0 2 1 9 S131 1 1

. . . . 1 11 0 1 0 11 S133 0 1

. . . . 0 11 0 1 0 11 S135 0 2

. . . .08 0 2 1 8 S154

. . .0

. . 1 12 . 0 0 12 S154C

. . 1 12

. . . 0 1 12 . 0 S191 1 1

. . . . 0 11 0 1 0 11 S2 0 1

. . . . 1 11 0 1 1 11 c. Source = Ogburn et al., 1996 d. The key to the shading is as follows: In-lake samples Class I no inflow criterion only Standard does not apply for this station and category64 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

• Administrative - Mixing zones and site-spe cific alternative criteria In addition, constructed wetlands may be appropriate for most land uses, assuming the availability of land. Alternative criteria could also potentially be established for some parameters in order to pr event the water quality crit eria from being exceeded. K12a.Strategies for Canals Three techniques have been devel oped for increasing dissolved oxygen in discharges from dams: oxygen in jection, air injection, and th e construction of spillways and weirs. Oxygen injection involves the us e of pure oxygen to increase levels of dissolved oxygen in reservoirs. It could potenti ally be used to in crease dissolved oxygen concentrations in the systems that drain to the lake. Air in jection is similar to oxygen injection, but atmospheri c air or compressed air is used to increase the dissolved oxygen concentration of the water body. It requires a compressor or ot her source of air, a diffuser system to distribute the air, and a pipe to deliver the air to the diffusers. Air injection may not be effective for large volume, intermitte nt flood control flows to the lake. Spillways and weirs could be constructed at the downstream sides of c ontrol structures to enhance aeration of water as it flow ed over the structures. These techniques could potentially be S236 1 1

. . . . . .01

. . S3 . 0

. . . . 0 12 . . 1 12 S308C 1 5

. .06

. .0506 S4 . 0

. . . . 1 12 . . 1 12 S65E

. .01

. . 0 11 0 1 0 11 S71

. .01

. . 0 11 0 1 0 10 S72

. .02

. . 2 10 0 2 1 9 S77 . 0

. .08

. . .008 S84

. .01

. . 0 11 0 1 0 11 TOTAL 16 38 6 49 0 122 17 233 9 84 24 351 Table 2-6. Results of fecal and total coliform measurements taken in lake okeechobee tributaries and in-lake stations from October 1993 to September 1994 cd (continued)

Station Fecal Coliforms Total Coliforms Inflow No Inflow Inflow No Inflow Class I Class III Class I Class III C lass I and III Class I and IIINumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamplesNumber of TimesCriterion ExceededNumber ofSamples

c. Source = Ogburn et al., 1996 d. The key to the shading is as follows: In-lake samples Class I no inflow criterion only Standard does not apply for this station and categoryLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 2: Watershed and Tributary Water Quality

65 applicable to the canals and pumped water control structur es that are commonly used to control surface water movement in the Lake Okeechobee watershed. In addition, sediment removal from canals and constructed wetlan ds provide management alternatives that could potentially be used for many land use categories in the watershed. K12b.Marina Operation Strategies Marina and boat operations, such as disposal of liquid wastes, and boat maintenance and cleaning can generate surf ace water pollution. Ma nagement strategies that could potentially be applicable to marinas on th e lake include liquid waste management and boat maintenance control me asures. Liquid waste management involves providing appropriate facil ities at marinas for di sposal of liquid wastes , such as oil, waste gasoline, solvents, antifreeze, and paints. Boat maintenance control measures include providing designated areas for boat maintenan ce and repairs, and re quiring their use for those activities. It also calls for regular cleaning of the maintenance areas to remove trash, sandings, paint chips, etc. Th e goal is to reduce the amount of solid wastes that are introduced to surface waters. Marinas and associated camping areas that have direct runoff into the lake from paved areas should develop an d implement stormwater treat ment systems. This would reduce the wastes associated with these recreation activities.
K12c.Administrative Measures Chapter 62, F.A.C., includes provisions that allow for relief from water quality criteria under certain circumstan ces, such as site-specific alternative criteria and mixing zones. These alternatives differ from the management strategies described previously, because the administrative m easures prevents criteria from being exceeded without improving water quality conditi ons. Administrative relief measures would likely be viewed by FDEP as acceptable only after thorough demonstration that other alternatives to improve water quality conditions are not feasible due to technical or financial limitations. Surface water quality regulations co ntained in Chapter 62-302.530, F.A.C., provide for the establishment of site-specific alternative criteria in certain cases when a water body does not meet appli cable criteria due to natural conditions or man-induced conditions that cannot be controlled or abated. In addition, the general criteria for surface waters (Chapter 62-302.520, F.A.C.) allow for establishment of alternative dissolved oxygen criteria using the same provisions included in 62-302.800, F.A.C. Site-specific alternative criteria may be approved for specific parame ters in all or part of a surface water body. A mixing zone may be granted to allow alte rnative criteria for specific parameters within the zone of mixing, provi ded the applicable criteria are met at the edge of the mixing zone. Chapter 62-4.244, F.A.C., descri bes the conditions under which a mixing zone may be requested, the criteria used byFDEP to evaluate requests for mixing zones, and the limitations that apply to mixing zone s. No mixing zone or combination of mixing zones is allowed to significantl y impact the designated uses of the receiving body of water.66 Chapter 2: Watershed and Tributary Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
A separate mixing zone must be defined for each parame ter, and a mixing zone cannot include a nursery area for a quatic biota. Mixing zone di mensions are determined by modeling, using anticipated con centrations of the specific pa rameter in the receiving water body.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

67 

## Chapter 3 IN-LAKE WATER QUALITY

In the mid-1980s Lake Okeechobee experi enced a number of very large algal blooms (Jones, 1987). These blooms were attr ibuted in part to an overabundance of nutrients, a process known as eutrophication. Algal blooms ar e cause for concern because they may contain toxins that affect fish and wildlife; theycreate taste and odor problems for drinking water; and when they die off and degrade, oxygen is removed from the water column causing fish kills and th e death of other aquatic life . Lake users also find these blooms unsightly, reducing their enjoyment of the resource. The 40 percent phosphorus load reduction goal developed to restore the ecological condition of Lake Okeechobee re sulted in a decline in the phosphorus load to the lake from the tributaries, but no reduction of phosphorus occurred within the lake. This was attributed in part to the huge amount of phosphorus that has accumulated over decades in sediments within the lake preventing the phosphorus concentration in the water column from declining. Along with discussing nutrients , this chapter also disc usses Class I water quality parameters within the lake, but no objectives or strategies ar e presented or discussed here. The in-lake and tributaries st rategies directed towards re ducing nonnutrient pollutants are combined. They are discussed in Chapter 2

. 

## A. GOALS, OBJECTIVES, AND STRATEGIES
Goal 1: Reduce in-lake nutrients to attain a more natural (lower) frequency of potentially harmful algal blooms Objective 1: Determine the economic, e ngineering, and ecological feasibility of reducing internal phosph orus loading from lake sediments Strategy 1: Determine the feasibilit y of removing the mud sediments from the lake’s pelagic region Strategy 2: Determine the feasibility of chemical treatment of mud sediments in the lake’s pelagi c region in order to “inactivate” soluble (biologically available) phosphorus Objective 2: Quantify rates of internal nutrien t loading from lake sediments so that accurate predictions can be made about the timing and extent of lake responses to potential management actions, such as sediment removal68 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
Strategy 1: Quantify the location, mobility, and phosphorus content and efflux of lake sediments Strategy 2: Continue the development and application of the Lake Okeechobee Water Quality Mode l and the Lake Okeechobee Hydrodynamic Transport Model to determine the feasibility of managing sediments for the re duction of internal loads Objective 3: Reduce uncertainty about in-lake sources, sinks, and cycling of nitrogen and phosphorus using rese arch and modeling approaches Strategy 1: Perform in-lake and laborat ory studies to measure aspects of the phosphorus cycle wh ere a high level of uncertainty currently exists Strategy 2: Perform in-lake and laborat ory studies to measure major aspects of the nitrogen cycle Objective 4: Quantify trends in limnetic an d marsh zone water quality and progress towards establishe d lake enhancement goals Strategy 1: Incorporate water quality da ta into a comprehensive plan for assessing trends in l ong-term ecological data that may serve as measures of manage ment activities and success Objective 5: Determine the impact of subm erged aquatic vegetation on lake water quality Strategy 1: Further monitoring and co mparisons with previous years will need to be conducted to determine if lowering the lake levels during the managed rece ssion during the sp ring of 2000 has had an impact on the water quality of the lake Strategy 2: Conduct empirical and modelin g studies to determine the impact submerged aquatic vege tation has on the water quality of the lake Objective 6: Determine the feasibility of aninternal phosphorus management program to meet th e phosphorus TMDL target of 140 tons per year and achieve an in-lake phosphorus concentration of 40 ppm in the pelagic zone of the lake Strategy 1: Demonstrate the feasibilit y and cost-effectiveness of removing the phosphorus laden mud using innovative dredging, material processing, and water treatment technologies.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

69 

## B. NUTRIENTS B1. Phosphorus Phosphorus is of part icular concern in this systembecause it is an essential element that contributes to eutrophication in Lake Okeechobee (Davis and Marshall, 1975; Federico et al., 1981; Joyner, 1972; Kissimmee-Okeechobee Basin Report, 1972). Phosphorus within the lake's water column increased dr amatically from 40 ppb in the early 1970s to 145 ppb in 2000 ( Figure 3-1 ).

A phosphorus load reduction goal was de veloped to restor e the ecological condition of Lake Okeechobee. This goal requires a 40 percent reduction in phosphorus loading to the lake, based on the data coll ected from 1973 to 1979 (Federico et al., 1981). Tributary phosphorus limi tations were based upon re aching an in-lake phosphorus concentration of 40 ppb by July 1992 as recommended by a modification of the Vollenweider (1976) nutrient loading model, described in SFWMD Technical Publication 81-2 (Federico et al., 1981). As controls within the basi ns surrounding Lake Okeechobee increased, a noticeable decline in the phosphor us load to the lake occurred from 1983 to 1993 ( Figure 3-2 ). Despite this load reducti on, no reduction of phosphorus occurred within the lake ( Figure 3-1 ). This in part was attribut ed to the huge amount of phosphorus that has accumulated over decades in se diments within this shallow lake ( Figure 3-3 ). As the external loads have declined, internal loads from the sediments have become more significant, acting as a buffer to the system and preventing the phos phorus concentration in the water column from declining. 0 20 40 60 80 100 120 140 160

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Total Phosphorus (ppb)

Figure 3-1. Lake Okeechobee annual average total phosphorus mean of stations L001 to L00870 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

100 300 500 700 900 1,100

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Phosphorus Loads (tons

Figure 3-2. Annual phosphorus loads to Lake Okeechobee

Figure 3-3. Phosphorus sediment concentrations (in parts per thousand) within Lake Okeechobee in 1988 and 1998Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

71 Part of the total phosphorus increase may be attribut ed to lake levels. A relationship exists between la ke levels and phosphorus within the western nearshore region of the lake, which ha s been sampled since 1986 ( Figure 3-4 ). At low stages, total phosphorus at the nearshore re gion is much less than in the open water region. At high stages, the values overlap. This indicates that at high stages the open water and nearshore areas mix rather well, with the phosphorus laden waters from the open water moving into the shallower nearshore regions. A general ex ception to this relationship occurred in 2000 when the annual average stage did not reflect the large cha nge in water levels from 16.16 on January 1, 2000, to 11.31 on December 31, 2000. These high values for both open water and nearshore were also influenced by Hurricane Irene in 1999 and another major storm in April 2000.

An example of this mixing is provided by spatial phosphorus ma ps for the periods before and after Hurricane Irene passe d over the lake in November 1999 ( Figure 3-5 ). In October, total phosphorus in most areas of the lake was less than 120 ppb, with values exceeding 100 ppb in the south central, northwe stern, and western regions. In November, almost the entire lake was above 160 ppb and the majority of the open water region (about 30 percent of the lake) was at 200 ppb. When the lake stage is lower, the water movement into and out of the nearshore region is more restricted. Inaddition, because of the shal low water column, more light reaches the bottom sediments st imulating the growth of s ubmergent aquatic vegetation. The growth of these plants not only reduces the amount of material being resuspended from the sediments, but also takes up ex isting phosphorus in the water column reducing water column phosphorus concentrations. Figure 3-4. Yearly mean phosphorus versus lake stage at the nearshore and open water stations for 1986 to 2000 y = 3.255x + 50.066 R 2

= 0.0711 p > 0.1

y = 10.064x - 84.805 R 2

= 0.362 P < 0.05 0 20 40 60 80 100 120 140

11 12 13 14 15 16 17 Stage (feet NGVD)Total Phosphorus (ppb) Open Water 2000 Nearshore 2000 Nearshore Open Water72 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

In current years, the lake stage ha s been very high, reducing the amount of submerged aquatic vegetation and increasing th e amount of phosphorus that remains in the water column. Because submerge d aquatic vegetation is important to the health of fish, birds, and other aquatic life, the District implemented a plan to reduce the lake stage from over 15 feet to 13 feet , beginning May 1, 2000. Because of the cont inued dry conditions, the lake stage fell to belo w 12 feet in June 2000. Moni toring of submerged aquatic vegetation has shown an increase in plants in the southern end of the lake and in some areas along the western shore ( Figure 6 in Chapter 4 ). Water clarity ha s also increased in these areas and preliminary data show that phosphorus levels have declined significantly in the nearshore areas. 

### B2. Nitrogen Nitrogen is another nutrien t that contributes to eutrophication of waters. One management action put into place in 1979 to help reduce nitrogen loads to the lake was the Interim Action Plan (SFWMD, 1979). This plan reduc ed nutrient loads to Lake Okeechobee from the EAA - Everglad es Protection District (EPD) ( Figure 3-6 ). The plan diverted as much nutrient-rich water away from the lake as possible and directed it southward towards the WCAs, while maintaini ng an adequate level of flood protection in the EAA-EPD. The Interim Action Plan has been successful in reducing the amount of nutrients that would have otherwise been pumped into the lake, and has exceeded its original goal of a 90 percen t reduction in nitrogen loading from the EAA-EPD. An additional benefit has been the reduced phosphor us loading to the lake. Currently planned Everglades restoration activitie s will allow for the diversion of some nutrient-rich waters to STAs, which should further reduce ba ckpumping from the EAA into the lake. Figure 3-5. Phosphorus water column concentratio ns in Lake Okeechobee during October and November 1999Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

73 The response of in-lake n itrogen to the reduction of nitrogen loads was dramatic ( Figure 3-7 ). Lake water concentrations of total nitrogen prior to the Interim Action Plan had increased from 1,500 to 3,000 ppm. After the Interim Action Plan and several BMPs were implemented, total nitroge n concentrations in lake water returned to the 1,500 ppm level. Total nitrogen concentrat ions have remained close to this value ever since. Because total nitrogen declined while total phosphorus did not, the lake water total nitrogen:total phosphorus ratios declined from near 35:1 in the 1970s to about 15:1 in the mid-1990s ( Figure 3-8 ). The ratio of soluble nitrogen:phosphorus (soluble nutrients are those readily available for uptake by algae) displayed a si milar decline and currently ranges between 4.5:1 to 6:1 ( Figure 3-9 ). According to Smith et al. ( 1995a) the lower ratios of total nitrogen:total phosphorus and soluble nitr ogen:phosphorus have made the water column of Lake Okeechobee more favor able for the proliferation of nitrogen-fixing blue-green algae. 5,000 6,000 7,000 8,000 9,000 10,000 11,000 12,000 13,000 14,000 15,000

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Nitrogen Load (tons)

Figure 3-6. Annual nitrogen loads to Lake Okeechobee

0 500 1,000 1,500 2,000 2,500 3,000

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Total Nitrogen (ppb)

Figure 3-7. Annual average nitrogen concen trations in Lake Okeechobee74 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Most lake algae are limi ted by phosphorus, but the years of excessive phosphorus loads and the successful reduction of nitrogen loads to the lake has resulted in Lake Okeechobee becoming secondarily nitrogen limi ted. To restore the ecological balance in the lake, phosphorus must become the limiting nutrient again. 0 5 10 15 20 25 30 35 40

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Total Nitrogen:Total PhosphorusRatio

Figure 3-8. Average annual ratio of total phosphorus to total nitrogen

0 2 4 6 8 10 12 14 16 18 20

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Soluble Nitrogen:Phosphorus Ratio

Figure 3-9. Average annual ratio of soluble nitrogen to phosphorusLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

75 

### B3. Chlorophyll a and Algal Blooms
From 1974 to 1977, while external nutri ent loads and lake water nutrient concentrations were increasing, chlorophyll a did not display any significant upward or downward trend ( Figure 3-10 ). Chlorophyll a was not measured from 1977 until the end of 1980. From 1981 to 1992, wh ile nitrogen concentrations declined and phosphorus concentrations remained high but stable, chlorophyll a increased significantly, from less than 20 to over 25 ppb. Since 1992, chlorophyll a has remained between 20 and 28 ppb. Havens (1995) studied the increase from 1981 to 1992, and proposed four explanations that could be tested in future research and/or modeling efforts: 1) phytoplankton growth was stimulated by the 3 degrees Celsius ( o C) rise in water temperatures that occurred during the 12-year peri od; (b) growth was stimulated by greater underwater light penetration that was caused by the 15 percent decline in average wind velocities (windgenerated waves resuspend bot tom sediments, reducing light penetration) during the 12- year period; (c) the 50 per cent decline in total nitroge n:total phosphorus and soluble nitrogen:phosporus ratios favor ed dominance by nitrogen-fixing blue-green algae, and many of these species have th e ability to float and, ther efore, may be sampled more readily; and (d) a great er dominance by large filaments of blue-green algae has led to less grazing impacts on the algal biomass by zoopla nkton. Regardless of the cause, it appears that excessive nutrient loading has establ ished conditions favorable for phytoplankton growth and the ultimate growthrates are now a function of less predictable meteorological or biological factors. This si tuation has been observed in other nutrient stressed lakes (Gophen, 1994).

0 5 10 15 20 25 30 35 40

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Chlorophylla(ppb)

Figure 3-10. Average annual chlorophyll a concentration in Lake Okeechobee76 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
The occurrence of algal blooms when the chlorophyll a concentration is greater than 40 ppb has increased over time as well (Havens et al., 1995a). A large amount of this increase occurs when the phosphorus concen trations in the near shore region exceed 40 ppb (Walker and Havens, 1995) ( Figure 3-11a ). In the open wate r region a similar relationship exists, but at higher total phos phorus concentrations the number of blooms declines, because higher phosphorus levels al so occur from sedime nt resuspension, and this resuspended sediment re duces light penetration into the water column preventing algal growth (James and Havens, 1996) ( Figure 3-11b ).

0% 2% 4% 6% 8% 10% 12% 14% 16% 18% 20%2030405060708090100110120130140150160170180190200210 Tota l P hosphorus (ppb)Cum ula tive Pe rceof sa m ple s 0% 5% 10% 15% 20% 25%102030405060708090100110120130140150160170180200210 Tota l P hosphorus (ppb)Cum ula tive Pe rceof sa m ple s

Figure 3-11. Cumulative percent of chlorophyll a samples classified as a bloom condition (chlorophyll a > 40 ppb) at a) nearshore stations and b) open water stations. 

## b. a.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

77 

## C. WATER QUALITY BUDGETS
Water and nutrient budgets were updated ba sed on the method used by James et al. (1995a). This includes summing 31 major infl ows and 7 outflows; and estimating volume and area with stage per volum e and stage per area curves on a monthly basis. These monthly values were summed or averaged for each year to produce a yearly budget. Atmospheric deposition was based on a consta nt 72 tons per year. Deposition to the sediments was estimated as the difference between the mass of material in December and January of the same year plus loads into the lake minus loads out of the lake. 

### C1. Water Budget Although Lake Okeechobee is the largest lake by area (approximately 650 square miles, 1,730 square kilometers) inthe southeastern United Stat es, it is also very shallow with an average depth just over eight feet ( Table 3-1 ). Because of the large surface area with respect to volume, a large percentage of the water evaporates within a year. Outflows from the lake are determined by a regulation schedule (see Chapter 5 ), which allows a certain amount of flow when stage exceeds a value determined by th e time of year. The objective of this regulation sc hedule is to maintain high water levels at the beginning of the dry season (November) to aid water supply, and to maintain lower water levels at the beginning of the wet season (May) for flood c ontrol. Based on surface outflows only, the turnover time for the lake averages almost three years, if evapor ation is included, this average decreases to one year. On average, evaporation accounts for more water loss than does surface outflow. 

### C2. Phosphorus Budget Phosphorus loads to the lake have declined from highs in the mid-1980s of over 600 tons to lows in the early 1990s of less than 500 tons ( Table 3-2 ). The loads in the late 1990s have increased as South Florida experienced three very wet years (1994, 1995, and 1998). This was followed by a ve ry dry year (2000), that c ontributed the least amount of phosphorus to the lake on record (215 tons). Because phosphorus is c onservative in lakes (it does not have a gaseous form), budgets estimate that on average 368 tons of phosphorus per year is deposited in lake sediments (net deposi tion). The proportion of phosphorus in the lake water colu mn that settles into the sedi ment has been declining over time to current levels near zero. This decline is importantin the regulation of phosphorus limits to the lake (see Models discussion below). It also de monstrates that despite some external load reductions, phosphorus concentr ations in the lake have increased. A comparison of current (1998) and past (1988) sediment phosphorus concentrations indicate that although total phosphorus in th e sediments has not increased, the amount of dissolved phosphorus has increased ( Figure 3-12 ) (Fisher et al., 2001). This indicates that the ability of sediments to absorb phosphorus has declined. Current predictions of water quality models show that it will take decades before in-lake total phosphorus concentrations respond to reduced external loads.78 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Table 3-1. Water budget for Lake OkeechobeeYearLake Area(1,000s of acres)AverageDepth(feet)Lake VolumeChange inLake VolumeInflowRainfallOutflowEvaporationErrorPercent ErrorTurnoverwithoutEvaporationTurnoverwithEvaporation

(1,000s of acre-feet) (years) 1973 409 7.9 3,238 692 2,437 1,554 618 2,209 -472 -14.6 5.24 1.15 1974 418 8.2 3,443 204 2,940 1,630 1,842 2,357 -166 -4.8 1.87 0.82 1975 416 7.8 3,247 -450 1,534 1,474 878 2,329 -252 -7.8 3.70 1.01 1976 420 7.9 3,299 210 1,942 1,350 1,528 2,298 744 22.6 2.16 0.86 1977 423 7.8 3,320 115 1,304 1,742 616 2,572 257 7.7 5.39 1.04 1978 445 9.4 4,174 1091 2,630 1,784 675 2,580 -69 -1.7 6.18 1.28 1979 445 10.0 4,451 276 2,969 1,639 1,958 2,697 324 7.3 2.27 0.96 1980 444 9.4 4,161 -1601 986 1,454 1,455 2,623 37 0.9 2.86 1.02 1981 361 7.2 2,583 -1086 822 1,097 762 2,189 -54 -2.1 3.39 0.88 1982 394 8.9 3,524 2539 3,135 1,792 576 2,291 480 13.6 6.12 1.23 1983 445 10.3 4,600 -214 2,997 1,977 2,703 2,628 143 3.1 1.70 0.86 1984 445 9.9 4,398 -641 1,931 1,649 1,909 2,771 458 10.4 2.30 0.94 1985 417 7.9 3,290 -590 1,284 1,475 1,054 2,523 228 6.9 3.12 0.92 1986 438 8.2 3,606 372 1,466 1,688 582 2,670 471 13.1 6.20 1.11 1987 442 8.7 3,843 619 2,219 1,551 860 2,682 391 10.2 4.47 1.08 1988 445 9.5 4,212 -743 1,512 1,477 1,225 2,737 229 5.4 3.44 1.06 1989 387 7.5 2,908 -896 1,283 1,453 1,317 2,376 61 2.1 2.21 0.79 1990 365 7.3 2,666 23 1,351 1,394 625 2,122 24 0.9 4.27 0.97 1991 415 8.6 3,568 1532 2,199 1,793 316 2,334 189 5.3 11.29 1.35 1992 445 9.4 4,196 -31 1,663 1,706 1,234 2,366 199 4.7 3.40 1.17 1993 443 8.7 3,870 -792 1,613 1,556 1,893 2,372 305 7.9 2.04 0.91 1994 443 9.1 4,050 1504 3,155 2,131 1,566 2,517 301 7.4 2.59 0.99 1995 445 10.4 4,626 -539 3,527 2,005 3,806 2,642 378 8.2 1.22 0.72 1996 445 9.3 4,124 -952 1,271 1,519 1,394 2,857 508 12.3 2.96 0.97 1997 435 8.3 3,631 1224 2,284 1,809 589 2,527 247 6.8 6.16 1.17 1998 445 10.1 4,504 -245 3,619 1,809 3,373 2,713 413 9.2 1.34 0.74 1999 443 9.4 4,169 -36 2,169 1,840 1,496 2,582 33 0.8 2.79 1.02 2000 396 8.1 3,197 -2090 679 1,258 1,480 2,379 -167 -5.2 2.16 0.83 Average 426 8.8 3,746 -18 2,033 1,629 1,369 2,498 187 4.7 2.74 0.97Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

79 Table 3-2. Lake Okeechobee phosphorus (P) budget in tons

Year Lake P Mass Net Change in Lake Content Surface P Load In Atmospheric Deposition Total P Load

In Total P Load Out Net Deposition Proportion of Lake Content Deposited into

Sediments Proportion of In Load Deposited into

Sediments 1973 238 -171 478 72 550 51 670 2.81 1.22 1974 228 74 813 72 885 227 584 2.56 0.66 1975 234 -76 327 72 399 66 409 1.75 1.02 1976 258 99 444 72 516 286 131 0.51 0.25 1977 264 -54 367 72 439 66 427 1.62 0.97 1978 394 54 670 72 742 96 592 1.50 0.80 1979 556 152 993 72 1065 224 690 1.24 0.65 1980 530 -372 215 72 287 145 514 0.97 1.79 1981 305 -222 363 72 434 79 578 1.90 1.33 1982 384 433 891 72 963 95 435 1.13 0.45 1983 581 -139 656 72 728 428 439 0.76 0.60 1984 615 -335 627 72 699 362 672 1.09 0.96 1985 368 -227 396 72 468 125 570 1.55 1.22 1986 313 31 503 72 575 59 485 1.55 0.84 1987 572 40 509 72 581 112 429 0.75 0.74 1988 647 -287 384 72 456 183 560 0.87 1.23 1989 362 365 350 72 422 186 -129 -0.36 -0.31 1990 385 31 397 72 469 85 353 0.92 0.75 1991 402 64 452 72 524 44 416 1.03 0.79 1992 494 -240 390 72 462 116 586 1.19 1.27 1993 475 139 285 72 357 233 -16 -0.03 -0.05 1994 505 270 594 72 666 180 216 0.43 0.32 1995 633 246 708 72 780 387 148 0.23 0.19 1996 680 -96 177 72 250 205 141 0.21 0.57 1997 491 409 471 72 543 86 48 0.10 0.09 1998 732 -239 815 72 887 569 557 0.76 0.63 1999 658 681 689 72 761 259 -180 -0.27 -0.24 2000 659 -94 143 72 215 322 -13 -0.02 -0.06 Average 463 19 504 72 576 188 368 0.80 0.6480 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT



### C3. Nitrogen Budget Nitrogen loading rates have averaged over 8,900 tons per year, with an output mass of about 3,500 tons per year ( Table 3-3 ). In terms of historic al trends, the rate of nitrogen loading increased significantly through the early 1980s, and then declined rapidly through the early 1990s, which is attributed to the decline in bac kpumping from the EAAEPD ( Figure 3-6 ) (James et al., 1995a). The mass-balance budget also shows that th e lake acts as a sink for nitrogen, with 62 percent of the nitrogen introduced into th e lake being retained on an average annual basis ( Figure 3-6 ). Much of this may be lost to the atmosphere as N 2 gas, from the process of denitrification. Deni trification may be very important to the overall nitrogen cycle of Lake Okeechobee. However, as is also the case for other bacterially-mediated transformations of nitrogen in Lake Okeechobee, it has not been directly measured, and represents an area for future study. Increased = 41 Decreased = 5 Decreased = 33 Increased = 9 Decreased = 52 Increased = 8

Decreased = 9 Increased = 73

Figure 3-12. Changes in total phosphorus (P) and dissolved reactive phosphorus (DRP) amounts at over 100 locations in Lake Okeechobee between 1988 and 1998.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

81 Table 3-3. Lake Okeechobee nitrogen (N) budget in tons

Year Lake N Mass Net Change in Lake Content Surface N Load In Atmospheric Deposition Total N Load

In Total N Load Out Net Deposition Proportion of Lake Content Assimilated Proportion of Loads Assimilated

by Lake 1973 6,781 2,116 6,827 3,669 10,496 1,592 6,789 1.00 0.65 1974 7,342 -1,421 8,695 3,669 12,365 4,170 9,615 1.31 0.78 1975 6,248 2,498 5,321 3,669 8,990 1,781 4,711 0.75 0.52 1976 8,880 4,398 5,492 3,669 9,161 4,752 10 0.00 0.00 1977 7,850 -6,013 6,042 3,669 9,711 1,871 13,853 1.76 1.43 1978 10,355 1,011 8,389 3,669 12,058 2,211 8,837 0.85 0.73 1979 11,695 2,157 8,325 3,669 11,994 6,194 3,643 0.31 0.30 1980 13,469 -954 3,279 3,669 6,948 4,544 3,358 0.25 0.48 1981 8,993 -6,478 5,694 3,669 9,363 2,755 13,086 1.46 1.40 1982 8,690 3,692 9,475 3,669 13,144 1,788 7,664 0.88 0.58 1983 9,692 4,815 6,792 3,669 10,461 6,581 -935 -0.10 -0.09 1984 9,345 -5,615 4,332 3,669 8,001 5,204 8,413 0.90 1.05 1985 7,028 -1,519 4,320 3,669 7,989 2,727 6,781 0.96 0.85 1986 7,652 433 3,805 3,669 7,474 1,627 5,414 0.71 0.72 1987 9,543 -3,819 5,304 3,669 8,973 2,551 10,242 1.07 1.14 1988 8,829 -2,244 3,261 3,669 6,930 2,985 6,188 0.70 0.89 1989 6,131 2,352 3,418 3,669 7,087 3,290 1,446 0.24 0.20 1990 5,794 155 2,710 3,669 6,379 1,442 4,783 0.83 0.75 1991 6,447 1,765 4,630 3,669 8,299 761 5,773 0.90 0.70 1992 7,645 -2,050 3,641 3,669 7,310 2,665 6,695 0.88 0.92 1993 7,421 1,877 2,981 3,669 6,650 5,759 -986 -0.13 -0.15 1994 8,513 3,046 5,841 3,669 9,510 3,761 2,703 0.32 0.28 1995 8,610 -925 6,585 3,669 10,254 8,373 2,806 0.33 0.27 1996 9,014 1,861 2,453 3,669 6,122 2,822 1,439 0.16 0.24 1997 7,817 2,690 5,023 3,669 8,692 1,634 4,368 0.56 0.50 1998 9,364 -3,397 7,772 3,669 11,441 7,837 7,000 0.75 0.61 1999 8,237 4,702 5,137 3,669 8,806 3,474 630 0.08 0.07 2000 7,804 -931 1,646 3,669 5,315 4,442 1,805 0.23 0.34 Average 8,400 150 5,257 3,669 8,926 3,557 5,219 0.62 0.5882 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT


## D. MODELS

Results from the modified Vollenweider Model show that the target phosphorus load and the observed phosphorus lo ad vary from year-to-year ( Figure 3-13a ). The target has been met in only one year (1991). To reduce the variability of the observed and target loads while maintaining the overall trend, a five-year movi ng average is calculated. This is done by creating a fiveyear window and averaging all years with in that window. As the window progresses forward, or rolls, in time the oldest ye ars are dropped and newer years are added. This five-year average shows some declin es in the loads to the lake ( Figure 3-13b ). This decline is more dramatic when observed as the amount of phosphorus that the observed load exceeded the target load ( Figure 3-14a ). The amount of excessive load declined in the 1980s and 1990s, but has increased since 1995. Th is can be attributed in part to the number of wet years in the late 1990s that ha ve increased the overall flow to the lake ( Figure 3-14b) . However, inflow concentrations wei ghted for flow have also increased in the past few years ( Figure 3-15 ).

Figure 3-13. Actual and target loads of phosphorus to Lake Okeechobee a) annually and b) as a five-year rolling average 0 200 400 600 800 1,000 1,200

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Total Phosphorus Loadin Tons per Year Observed Load Target Load 

## a.

0 200 400 600 800

1976 1979 1982 1985 1988 1991 1994 1997 2000Total Phosphorus LoadTons per Year Observed Load Target Load 

## b.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

83 Figure 3-14. Five-year rolling average of a) tons of phosphor us above target and b) inflow to Lake Okeechobee 0 50 100 150 200 250 300 35072-7675-7978-8281-8584-8887-9190-9493-9796-00

YearsTons of Phosphorus AboveTarget 

## a.

1,000 1,500 2,000 2,500 3,00072-7675-7978-8281-8584-8887-9190-9493-9796-00

YearsInflow Thousands of Acre-ft 

## b.84 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

After 1986, the modified Vollenweider m odel consistently under predicted the observed value of total phosphorus in the lake ( Figure 3-16 ). Havens and James (1997) suggested that this model ignored the larg e load sediments contributed to the water column of the lake. These sediments can poten tially produce an internal load comparable to the external loads of the lake (Moore et al., 1998). Other mode ls have been proposed that will estimate tota l phosphorus within the lake, includi ng representations of sediments. Models that assume a constant settling rate of phosphorus fr om the water column to the 100 150 200 25072-7675-7978-8281-8584-8887-9190-9493-9796-00

YearsInflow Concentration(ppb)

Figure 3-15. Five-year rolling average of phosphorus concentrati ons in inflows to Lake Okeechobee

0 20 40 60 80 100 120 140 160

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Total Phosphorus(ppb) Observed

Predicted

Figure 3-16. Comparison of the modified Vollenweider model total phosphorus predictions to observed data for 1973 to 2000Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

85 sediments overpredict total phosphorus in the 1970s but pred ict current phosphorus values well ( Figure 3-17 ). To predict the historical record of the lake well, these models have to change the net set tling rate over time.

A number of hypotheses have been suggested to account for the decrease in net settling. The first relate s to lake levels and wi nd. Lakewide total phosphorus concentrations are strongly correlated wi th water levels (Canfield and Hoyer, 1988; Havens, 1997) and wind (Maceinaand Soballe, 1990). Severa l mechanisms have been proposed to explain the relationship, incl uding 1) flooding of marsh vegetation and subsequent phosphorus release from dying plants; 2) enhanced water column stability when water levels are high, leading to lo w oxygen conditions and subsequent soluble phosphorus release from sediment s; and 3) the reduction of submerged aquatic vegetation under high lake level conditions that rem ove and retain phosphorus from the water column. The first two hypothesis were tested during the 1980s and 1990s. Considerable research was directed at th e marsh flooding process in th e late 1980s, and the general conclusion was that the marsh zone is generally hydrologicall y uncoupled from the limnetic zone, but when water exchange does occur, the marsh zone is a strong sink for phosphorus (Sheng and Lee, 1 991; Dierberg, 1992; Harris et al., 1995). Research efforts began in the summer of 1996 to determine if a relations hip exists between dissolved oxygen and soluble reactive phosphorus in the water column of the lake. Three years of daily dissolved oxygen and weekly to biweek ly soluble reactive phosphorus data do not indicate any relationship. The third hypothesis on the relationship between in-lake phosphorus and water levels, the impact of the reduction of s ubmerged aquatic vegetation, has been more recently tested. When the lake stage is lowe r, more light reache s the bottom sediments stimulating the growth of s ubmergent aquatic vegetation. Th e growth of these plants not only reduces the amount of mate rial being resuspended from the sediments, but also take 0 20 40 60 80 100 120 140 160

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Total Phosphorus (ppb)

Observed Predicted

Figure 3-17. Comparison of a simple mass balance model total phosphorus predictions to observed data for 1973 to 200086 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
up existing phosphorus, reducing the overall phosphorus concentration in the water column. The current effort to lower the lake levels has pr ovided an opportuni ty to test this hypothesis. Forty locations where submerged a quatic vegetation has been observed in the past were visited in April 2000 and submerged aquatic vege tation was found at only two of the sites. At this time the lake stage was over 14.5 f eet National Geodetic Vertical Datum (NGVD). By the end of Septem ber, 2000, a mapping program found over 43,000 acres of submerged aquatic vegetation in the lake (see Chapter 4 ). In April 2000, the lowest total phosphorus concentration measured in the lake was 126 ppb at the Palm Out station. As of this wr iting, the highest total phosphorus va lue measured in the lake was 58 ppb in May 2000 at L006. These May values do not include the central L001 to L005 stations. However, the values that were observed were much less than any values obtained in April. In previous years, total phosphorus drops noticeable from April to May, but this decline was not as dramatic in 1998 or 1999 as it was in 2000. Fu rther monitoring and comparisons to previous years will determine if the recessi on truly has had an impact on the water quality of the lake. A simple model that handles this re lationship between submerged aquatic vegetation and lake levels ad equately predicted yearly to tal phosphorus values for Lake Okeechobee ( Figure 3-18 ). The simulation included data from the 1970s. These model results do not prove that submerged aquatic ve getation has or has had a large impact on the water quality of Lake Okeechobee. However, it does suggest that further empirical and modeling studies regard ing these relationships should be conducted.

0 20 40 60 80 100 120 140 160

1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Total Phosphorus (ppb)

Observed Predicted

Figure 3-18. Comparison of total phosphorus predictions from a simple mass balance model, which includes a submerged aquatic vegetation component, to observed data for 1973 to 2000Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

87 

### D1. Total Maximum Daily Load and Water Quality Models
On December 31, 1999, the USEPA set a phosphorus TMDL for Lake Okeechobee of 0.05 ppm or 50 ppb for the wate rs flowing into the lake. This is much less than the current SWIM target and is based on the Lake Okeechobee Water Quality Model, a more sophisticated water quality model that in cludes the impact of sediments. The Lake Okeechobee Water Quality Model was deve loped by SFWMD staff using a modified version of the Water Analys is Simulation Package that is currently supported by the USEPA. This model simulates the oxygen, phos phorus, nitrogen, and silica cycles within the lake; suspended solids; and three algal groups: diatoms, gree ns, and cyanobacteria ( Figure 4 ). The model was developed to answ er two questions: 1) how will Lake Okeechobee respond to decrease d phosphorus loads? and 2) under what conditions will algal blooms occur? This model includes se diment water intera ctions and has been calibrated and verified to monthly data observed from 1983 to 1996.
The USEPA used this model to determin e what inflow loads the lake could assimilate, given lake conditions prior to the 1900s. Theyran a number of scenarios and determined that at an inflow concentrati on of 84 ppb, the sediment concentration did not change ( Figure 5 ). The USEPA then went furthe r by taking a number of loading conditions and, based on current lake and se diment conditions, dete rmined the amount of

Loads and

Flows Temperature Solar Radiation Sediment Resuspension

Sediment Dissolved Oxygen Carbonaceous

Biological Oxygen Demand Ammonium Nitrate

and Nitrite Inorganic Suspended

Solids

Dissolved Reactive Phosphorus Dissolved

Silica

Organic Nitrogen

Particulate Silica Cyanobacteria
Diatoms Green Algae Organic Phosphorus

Labile Dissolved Moderately

Labile Nonreactive

Figure 4. A diagram of the Lake Okeechobee Water Quality Model (USEPA, 2000)88 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

time it would take to reach the in-lake target goal of 40 ppb. The USEPA determined that a target value of 50 ppb in the inflow, which on average is a phosphorus load of 218 tons per year, was an adequate TMDL to reach the target in a reasonable time frame, and to meet a minimum margin of safety criteria. The model predicts that the majority of the in-lake reduction response will occur in the first 20 to 30 years, so that desp ite the long period of time it will take to reach the target, the in-lake concentrati on will be reduced significantly in a reasonably short period of time ( Figure 6 ).
Two concerns about the use of this model exist. The first is that the model does not adequately predict the observed data from the 1970s ( Figure 3-17 ). This is a problem of all mass balance models used to this point that assume a constant settling rate throughout the observed history. As desc ribed above, some mechanism must be found to explain a change in this settling rate. One possibility is the relations hip between lake levels and submerged aquatic vegetation. For the Lake Okeechobee Water Quality Model to handle the submerged aquatic vegetation, three things are needed: 1) the model must be enhanced to include a submerged aqua tic vegetation component; 2) the model must work on a spatially-segmented scale to represent shallow areas where submerged aquatic vegetation can grow; and 3) deeper ar eas where mud sediments exis t and the hydrodynamics of the lake between the grids must be spec ified by the Lake Ok eechobee Hydrodynamic Sediment Transport Model. The second concern is that the predictions of the model contain a large amount of uncertainty. This uncertainty is being quantified through a study that will determine the range of potential values in each model parameter, and determine the possible range of out comes if these parameter values are changed within the range of acceptable values (SFWMD Contract C-10668). 85 86 87 88 89 90 91 92

0 50 100 150 200 250 300 350

80 ppb Inflow 84 ppb Inflow 85 ppb InflowTotal Phosphorus Sediment (mg/L)

Year

Figure 5. Simulations of the Lake Okeechobee Water Quality Model under pre-1910 conditions to determine the maximum phosphorus inflowconcentration that can be absorbed by the sediments without increasing phosphor us concentrations in the water column (USEPA, 2000)Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

89 In 2000, the FDEP assembled a TMDL Tec hnical Advisory Committee to develop its own phosphorus TMDL for Lake Okeechobee. They have investigated a number of simple mass balance and empi rical models, as well as th e Lake Okeechobee Water Quality Model. The TMDLs determined from each of these models were very similar to one another and were similar to the USEPA pr oposed TMDL. The final TMDL accepted was 140 metric tons or approximately 40 ppb ininflow waters (FDEP, 2001). The only difference may be the amount of atmosphe ric deposition assume d. The Lake Okeechobee Water Quality Model assumed a deposition of 72 tons per year, which is the same value used in the determination of phosphorus budgets to the lake in this SWIM plan. However, because of the tremendous uncertainty in m easurements of atmospheric deposition (Ahn and James, 1999, 2000) and the reduction of atmospheric deposition over large bodies of water, the Lake Okeechobee TMDL Technical Advisory Committee recommended using an atmospheric load less than half of the current estimate. Further research on atmospheric deposition in South Florida is curren tly under way (SFWMD Contract C-10740). 0 0.05

0.1 0.15

0.2 0.25

0.3

0 50 100 150 200 250 300 350

250 Tons (70 ppb)Total Phosphorus (mg/L)

70 Tons (0 ppb) 275 Tons (80 ppb) 173 Tons (40 ppb) 198 Tons (50 ppb) 224 Tons (60 ppb) Year

Figure 6. Predictions of in-lake phosphorus conc entrations under different inflow loads (USEPA, 2000)90 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT 

### D2. Hydrodynamic and Sediment Transport Model The Lake Okeechobee Hydrodyna mic and Sediment Transport Model (Jin et al., 2000a) simulates hydrodynamic and sediment transport proces ses in Lake Okeechobee. It also provides detailed long-te rm information regarding ci rculation patterns, sediment distribution, and sediment resuspension/d eposition under differen t hydrological and manmade conditions (e.g., high/lo w lake stages, storm even ts/hurricanes, and sediment removal/dredging). These results can be us ed in a spatially-se gmented water quality model to predict the impacts of sediment resuspension and movement of nutrients on both nearshore and pelagic ar eas of Lake Okeechobee.
Wind influences both lake circulation and sediment resuspension. The circulation patterns vary with wind veloci ty and water depth. Wind also affects sediment resuspension through the production of waves. Wave height is determined by both wind velocity and fetch, which is the length of e xposed water surface in the dire ction that the wind blows. In general, the larger the wind ve locity and fetch, the larger th e wave height and wave period. Due to shallow depths in the lake, energy generated by wind is di rectly transmitted through the water column to the lake bottom. If the transmitted energy exceeds the sediment's critical shear stre ss, resuspension occurs (Jin and Ji, 2000). The bottom stresses resulting from wind generated surface waves are the major causes of sediment resuspension and transport in La ke Okeechobee (Jin and Wang, 1998). An example of these relationships is demonstrated for January 21, 2000. On this date, the wind was blowing in the southeaste rn direction at 6 m iles per second, and the lake had a significant wave height of over 70 centimet ers in the deepwater areas ( Figure 3-1 ). Simulated circulation pa tterns in the top and botto m layers on this day were very similar ( Figures 3-2 and 3-3 ). Sediment concentrati ons exceeding 200 ppm were predicted in the central regi on of the lake. The resuspensi on of sediment is strongly associated with significant wave height, and the transport of the suspended sediment in the lake is totally driven by the currents.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

91 Figure 3-1. Lake Okeechobee hydrodynamic sediment transport model predictions of wave height on January 21, 200092 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Figure 3-2. Lake Okeechobee hydrodynamic sediment tr ansport model predictions of surface currents and sediment concentr ations on January 21, 2000Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

93 Figure 3-3. Lake Okeechobee hydrodynamic sediment transport model predictions of bottom currents and sediment concentr ations on January 21, 200094 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT


## E. SEDIMENT ASSESSMENT
In 1998, as part of th e Sediment Remapping Study (Reddy, 1998), 31 sediment samples were taken from the lake and measur ed by the FDEP's Central Laboratory for a series of herbicides, pesticides, and their breakdown products. Of the 64 organics measured, only two, DDD, p, p’ and DDE, p, p’, were detected ( Figures 3-4 and 3-5 ). These organics are breakdown products of DDT, a toxic a nd persistent chemical widely used for agricultural pest control in the United States from the 1940s to the 1960s. DDD, p, p’ and DDE, p, p’ were f ound in seven and nine of the 31 samples, respectively. The amounts detected were above th e minimum detection value fo r the analytical procedure, but were below an amount that c ould be accurately measured. The Development and Evaluation of Sediment Qua lity Assessment Guidelines (MacDonald, 1994) lists the threshold and probable effect levels of these organics as 1.2 and 7.8 ppb for DDD p,p’, and 2.1 and 374 ppb for DDE p,p’, respectively. Thus , the amount of DDD, p, p’ and DDE, p, p’ in the sediments of Lake Okeechobee are a cause for so me concern as the measured values exceeded the threshold levels, but fo r the most part they did not exceed the probable effect levels.

No Sample

Below Detection Limit
5 to 12 ppb

0 20 40 60

kilometers
F igure 3-4. Locations within Lake Okeechobee where DDD p,p’ was detected in samples taken in 1998Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

95 

### E1. Lake Okeechobee Sediment Management Feasibility Study At present, more than 51,600 metric tons of phosphorus is in the mud sediments of Lake Okeechobee. This sediment material, which appears to have accumulated in the lake during the last 150 years (Brezonik and Engs trom, 2001), frequently is resuspended into the water column by wind and waves (Macien a and Søballe, 1990). When this occurs, phosphorus is transported into the water column (interna l loading) at a magnitude approximately equal to extern al loading from the watershe d (Moore et al., 1998). Due to this high internal loading, th e lake may not respond to re ductions in external phosphorus inputs (Steinman et al., 1999). This situation is typical of shallow, nutrient-enriched lakes (Sas, 1989), which generally re quire in-lake restoration measures to achieve recovery (Moss et al., 1999).
Under direction of the South Florida Ecosystem Restorat ion Working Group, a multiagency team, known as the Lake Okeec hobee Issue Team, developed an action plan for the rehabilitation of Lake Okeechobee. To ensure recovery of Lake Okeechobee from cultural eutrophication, the acti on plan recommended removal of all or part of the mud 0 20 40 60

kilometers No Sample

Below Detection Limi t
2.5 to 15 ppb

Figure 3-5. Locations within Lake Okeechobee where DDE p,p’ was detected in samples taken in 199896 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

sediments, to the maximum ex tent practicable, in order to substantially reduce internal phosphorus loading. If the sedime nts are removed, they must be processed and disposed of in such a way that will not contribute phosphorus to the la ke or other regional water resources. The mud in Lake Okeechobee covers an area greater th an 80,000 hectares and has a volume of approximately 200 million cubic meters. This amount of material is an order of magnitude greater thanhas ever been removed fromany lake in the world (Cooke et al., 1993). Given these issues, a comprehensive feasibility study must be conducted to provide detailed informati on regarding the benefits, pot ential concerns , and costs associated with alte rnatives for addressing the internal phosphorus loading issue. Therefore, the objective of the Lake Okeec hobee Sediment Manageme nt Feasibility Study is to analyze various alternat ives in order to determine the best method of sediment treatment that will reduce in ternal phosphorus loading in Lake Okeechobee. Feasibility study goals will be achieved using an objecti ve methodology that al lows for review and input by experts and stakehol ders throughout the study proce ss. The final deliverables from this study, which ar e expected in October 2003 

### , will be used in conjunction with a multiple criteria decision pr ocess and public/interagency i nput in order to make final recommendations to the Governing Board of the SFWMD.


### E2. Lake Okeechobee Pilo t Dredging Project In 2000, when the District began the Lake Okeechobee Sediment Management Feasibility Study, the objective was to analyze various alternatives inorder to determine the best method of sediment treatment thatwill reduce internal phosphorus loading in Lake Okeechobee. One of the sediment treatment alternatives u nder consideration is dredging. However, the fluid ch aracteristics of the sediment, the large area of its coverage, the shallow depth of sediment, and the envi ronmental sensitivity of Lake Okeechobee will present a very considerable challenge fo r dredging. The use of conventional dredging technologies for this project may not suffice and more advanc ed technologies need to be evaluated. In the fall of 2000, the District initiated a contract to conduct a pilot dredging project in Lake Okeechobee. The project is scheduled to begin in March 2002. It will demonstrate the feasibility and cost-effectiv eness of removing the phosphorus laden mud layer using innovative dredgi ng, material proce ssing, and water treatment technologies. Permit applications have beendeveloped and are under review , prior to submittal to the appropriate agencies. The results of this project also will provide essential information for input to the Sediment Management Feasibili ty Study that is being conducted concurrently under a separate District contract.


## F. CLASS I WATER QUALITY PARAMETERS

An evaluation of the District's water quality and biological monitoring data, collected at ten open water stations duri ng the period beginning in 1972 and ending in 1991, have been reported (CH2M Hill, 1995; Ogburn et al., 1 996). Since then, additionalLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

97 data have been collected and added to update this report. Because Lake Okeechobee is classified as a drinking wa ter source in Chapter 62- 302.400, F.A.C., in-lake conditions were compared to Class I standards. Obse rved data from 1988 to 2000 were compared to Class I criteria (effective De c. 26, 1996) (Chapt er 62-302.530, F.A.C.). The results of this comparison are presented in Table 3-4 . The evaluation considered both the frequency and the magnitude of the instances in which the criteria were exceeded.

Table 3-4. Percentage of instances that Class I criteria were exceeded within Lake Okeechobee aSTATIONpHAlkalinityConductivityChlorideDissolvedOxygenTotal DissolvedSolidsTurbidityUn-IonizedAmmoniaNitrateIronArsenicCadmiumCooperLeadZincMercury

L001 23.1 1.0 1.5 0.0 0.0 0.0 3.5 0.0 0.0 63.3 0.0 2.9 0.0 0.0 0.0 0.0 195 201 196 197 194 2 201 191 178 49 37 34 34 34 34 34 L002 17.7 0.0 0.0 0.0 0.0 0.0 6.2 2.0 0.0 66.7 0.0 0.0 0.0 0.0 0.0 0.0 232 205 234 203 232 2 258 255 226 48 36 33 33 33 33 33 L003 4.6 0.0 0.0 0.0 0.5 0.0 13.4 0.0 0.0 87.2 0.0 0.0 0.0 0.0 0.0 0.0 195 202 196 198 195 2 202 193 180 47 36 33 33 33 33 29 L004 2.6 0.0 0.0 0.0 0.0 0.0 14.9 0.0 0.0 87.5 0.0 3.0 0.0 0.0 0.0 0.0 194 201 195 195 193 2 201 191 177 48 36 33 33 33 33 31 L005 43.2 0.0 0.4 0.0 0.4 0.0 7.4 0.4 0.0 44.7 0.0 0.0 0.0 3.1 0.0 0.0 227 202 228 199 225 2 258 251 220 47 36 32 32 32 32 33 L006 5.0 0.5 0.0 0.0 0.0 0.0 16.9 0.0 0.0 75.5 0.0 0.0 0.0 0.0 0.0 0.0 239 206 241 205 238 3 248 247 229 49 37 35 35 35 35 30 L007 14.9 0.0 0.0 0.0 0.0 0.0 8.7 0.0 0.0 49.0 0.0 0.0 0.0 0.0 0.0 0.0 201 208 202 206 199 3 207 204 193 49 37 35 35 35 35 30 L008 14.4 0.0 0.0 0.0 0.5 0.0 18.8 0.0 0.0 79.6 0.0 0.0 0.0 0.0 0.0 0.0 188 197 189 191 187 2 197 186 171 49 37 34 34 34 34 34 LZ2 42.6 0.0 2.2 0.0 0.0 0.0 2.0 0.0 0.0 39.1 0.0 0.0 0.0 0.0 0.0 0.0 94 97 93 96 96 0 98 90 76 23 23 20 20 20 20 23 LZ30 18.6 0.6 0.6 0.0 1.2 0.0 11.9 0.6 0.0 52.4 0.0 3.0 0.0 0.0 0.0 0.0 172 179 174 178 171 3 177 177 164 42 35 33 33 33 33 27 Total 17.5 0.2 0.4 0.0 0.3 0.0 10.7 0.4 0.0 66.1 0.0 0.9 0.0 0.3 0.0 0.0 1,937 1,898 1,948 1,868 1,930 21 2,047 1,985 1,814 451 350 322 322 322 322 304 a. The upper number in each cell indicates the number of sa mples collected, while the lower number represents the percentage the criteria was exceeded. The key below explains the color coding 25% or more of samples exceed criteria Between 10% and 25% of samples exceed criteria Less than 10% of samples exceed criteria

ND Not determined

No criteria has been established98 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
Results of the study indicate that Class I crit eria for iron is exc eeded at all stations in more than 25 percent of the samples ( Table 3-4 ). The Class I criteria were exceeded for pH at five stations in more than 10 percent of the samples and two stations in more than 25 percent of the samples. Turbidity exceeded the Class I standard at five stations in more than 10 percent of the samples. The mechanis ms, most of which are natural, that caused the criteria to be exceede d are discussed below. 

### F1. pH The Class I criteria for pH include minimum (6.0) and maximum (8.5) values. The in-lake stations had between 94 and 239 observations for this parameter. The incidence of criteria being exceeded ranged from 2.6 percent at L004 in the eastern central region of the lake to nearly 43.2 percent at L005 in the central western regi on of the lake. All but one of the instances were values a bove the maximum criterion of 8.5, and were likely caused by algal photosynthesis. Since the average pH fo r the lake is 8.1, pH measurements over 8.5 are rather common and do not truly repres ent degraded conditions of the lake. 

### F2. Alkalinity

The Class I criterion for al kalinity requires a minimu m value of 20 ppm calcium carbonate (CaCO 3 ). Of the 1,898 observati ons, only four were less than the minimum, and these occurred at one station twice and at four other stations once. 

### F3. Dissolved Oxygen

The Class I criterion for dissolved oxygen requires a minimum value of 5 ppm. The in-lake stations had be tween 96 and 238 measurements for this parameter. Four stations had one or two m easurements below the minimum. These low values were probably caused by decomposit ion of algae and plants. 

### F4. Turbidity The Class I criterion for turbidity is 29 nephelometric turbidity units (NTUs) above background. The background value for eachstation was determined as the median value; half of all values are lower and half of the values ar e higher than the median value. This criterion was exceeded at all sta tions for 2.0 percent to 18.8 percent of all observations. These instances are related to th e shallow nature of the lake and wind-driven resuspension of mud bottom sediments.


### F5. Un-ionized Ammonia

The Class I criterion for un-ionized am monia is 20 ppb. Between 90 and 255 total observations were made at each of the in-lake stations and only one to five observations at three stations exceeded the criterion. This is considerably lower than the frequency on observed in inflow water. The ability of alg ae and bacteria to use ammonia as a nitrogenLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 3: In-Lake Water Quality

99 source appears to minimize th e potential for the un-ionized ammonia criterion to be exceeded in the lake.


### F6. Iron

The Class I criterion for ir on is 0.3 ppm, which will prevent discoloration and staining by domestic water supplie s. This criterion was exceed ed at all of the in-lake stations. The percent of times the criteri on was exceeded ranged from 39.1 to 87.5 percent of the observations. This amount of iron with in the water could affect drinking water quality, perhaps causing objec tionable taste and staining of dishes and clothes. The widespread distribution of high iron concentrations in the lake and inflows indicates that this is a natural condition. The mo st likely source is local soils. 

### F7. Arsenic, Cadmium, Copper, Lead, and Zinc The Class I criteria for arsenic is 50 ppb. The Class I criteria for cadmium, copper, lead, and zinc are calculated as a function of water hardne ss, and, therefore, do not have specific values. Very few observations have been made for these five parameters (generally less than 40 per station for the 12-year period), and the criteria were rarely exceeded. No stations exceeded the criteria for arsenic, copper, or zinc. Three stations exceeded the criterion for cadmiu m once and another for lead once. 

### F8. Mercury All mercury data, with the exception of three samples, were reported as “below detection limit.” Any observation above the de tection limit, was fl agged as not meeting the quality assurance/quality control (QA/QC) standard for precision or accuracy. Since the minimal detection limit fo r mercury analysis (0.02 ppb) wa s above the Class I criterion of 0.012 ppb, no meaningful evaluati on of compliance is possible.


### F9. Other Class I Criteria Other aspects of water quality, includi ng pesticides, polychlorinated biphenyls (PCBs), biological integrit y, and total coliforms, were not measured at the in-lake stations, and as such, represent an area where informat ion is needed. It is also important that compliance with other Class I criteria be as sessed, since conditions in the lake may change from year-to-year. Although a c ouple of total dissolved solids samples were taken at each station, the numbers are so sm all that no meaningful evaluation is possible. Thus, it is recommended that more samples be analyzed for dissolved solids.100 Chapter 3: In-Lake Water Quality Lake Okeechobee SWIM Plan - June 21, 2002 DRAFTLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

101 

## Chapter 4 ENVIRONMENTAL RESOURCES

Lake Okeechobee is the central component of a larg e interconnected aquatic ecosystem in South Florida that extends fr om the headwaters of the Kissimmee River to Florida Bay. Prior to intensive human deve lopment in South Flor ida, the hydrology of Lake Okeechobee was coupled di rectly to that of the meandering Kissimmee River and its marsh ecosystem in the north, an d to the great expanse of Ev erglades marsh in the south ( Figure 4-1 , PAST). During periods of high rainfall , lake water levels may have exceeded 20 feet NGVD and water exited the lake at it s southern end into a number of blind river channels and as overland sheetflow into the Evergl ades sawgrass community. After two major hurricanes and associated floods kill ed over 2,000 people in the 1920s, the USACE constructed a system of gates, dikes, pumps, and cana ls around Lake Okeechobee and throughout South Florida. This effort, the C&SF Project, was completed in the mid-1960s and today the lake is entirely surrounded by an earthen di ke. All water inflows, except Fisheating Cr eek to the west, and outflows are controlled. Maximal water levels in the lake are regulated and the natural connections between the lake and the Everglades marsh have been lost.
Lake Okeechobee is now smaller than unde r natural conditions, and water levels are lower ( Figure 4-1 , PRESENT). The littoral zone o ccupies about 25 percent of the lake's surface along the southe rn and western shores and it occurs in a region that was once under water. As a result of the dike, the littoral zone is uncoupled from land that once supported a much larger marsh to the west . That land now supports agricultural crops. Despite lower water levels from a historical perspective, fl ooding in the li ttoral zone in recent years has resulted in serious impact s. Because the dike prevents the gradual outward expansion of marsh habitat that normally may have occurred, additional water (greater than 15 feet NGVD) in the lake re sults in deeper flooding of the littoral zone. Likewise, under extreme low wate r level conditions (less than 11 feet NGVD) nearly the entire littoral zone is dry and unavailable as habita t for fish and other wildlife. This occurs because a relatively sharp dept h gradient occurs at the inte rface between this region of the lake and the adjacent pelagic (open water) zone.
When the water level in Lake Okeechob ee increases above a seasonally variable maximum (the lake stage that triggers discharge decisions on any given date based on a USACE regulation schedule), di scharges can occur through canals connected to estuaries on the east and west coast of Florida. As a result of past discharges, the estuarine ecosystems have experienced unnaturally large inputs of fr esh water follow ing periods of high rainfall in the Lake Okeechobee watershe d, and estuarine fish, shellfish, plants, and other biota have been impacted.102 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Figure 4-1. Hydrologic and morphological conditions of Lake Okeechobee before human impacts (PAST), during the last 40 ye ars (PRESENT), and anticipated when the CERP is completed (FUTURE)Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

103 A number of management effort s have been directed at the issues associated with littoral zone flooding, drying, and high fres hwater discharges to the estuaries: • The WSE schedule, a lake regula tion schedule that uses climate forecasting, was developed and adopt ed late in the summer of 2000. This schedule allows proactive disc harges of water from the lake to minimize damage to the littoral zone and the estuaries during periods of high rainfall as well as conservation of water in the lake when dry conditions are predicted. • Minimum water level criteria for th e lake were developed as required by state law. • An emergency lake recession operati on was carried out in the spring of 2000 to provide a period of lake le vels below 13 feet NGVD so that submerged plant beds could recove r from damaging high water levels that occurred in between 1994 and 1999. • A set of adaptive management prot ocols are under development to help the District and the USACE take full advantage of the flexibility in the WSE schedule, in order to maximize be nefits of the lake for its multiple
uses. Lake Okeechobee once played a critical role in suppl ying fresh water to the Everglades marsh. As a result of the C&SF Project and the other human developments in South Florida, this water supply has been great ly reduced, and may in part be the cause of ecological imbalance in the Everglades ecosystem. The USACE and the SFWMD launched a regional re storation project, the CERP, in 2000. This project involves major changes both in the infrastructure and operation of the C&SF syst em. It is designed to restore a more natural flow of water within the boundaries of the ecosystem, while providing the flood protection and water supply that will be required by South Florida's growing human population. The regional project is expected to result in substantial ecological benefits to Lake Ok eechobee, as a result of a less extreme variability in lake stages ( Figure 4-1 , FUTURE). A key part of CERP is a process called adaptive assessment, which involves applied science and monitoring of a suite of ecological performance measures. The result s of that science and monitori ng will be used to evaluate the benefits of the CERP as it unfolds, and as th e basis for recommending modifications to the plan where they are necessary. Adaptive assessment also incl udes cause-and-effect ecological research and modeling aimed at reducing the uncertainty of management decisions. Using SWIM funds, assessments have been initiated prior to the CERP and provide a sound scientific basis for the lake component of the re storation program. Some areas of uncertainty still exis t and are reflected in the object ives and strategies of this SWIM plan update. In addition to altered hydrology, La ke Okeechobee has been impacted by excessive inputs of nutrients, in particul ar phosphorus (described in detail in Chapter 2 and Chapter 3 ). These phosphorus inputs, origin ating primarily from agricultural activities in the lake's north ern watershed, have led to incr eases in lake water nutrient concentrations, more frequent algal blooms, and dominance by algal and animal species104 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
that are tolerant of eutrophi c conditions (Warren et al, 1995; Havens et al., 1996a). These trends and their possible reve rsal due to management pr ograms have the potential to dramatically affect the values of the ecosystem for humans and wildlife. A third human-related impact on La ke Okeechobee is the introduction and proliferation of exotic specie s. To date, the most significant impacts ha ve been associated with two exotic plants: Melaleuca quinquenervia (melaleuca) and Panicum repens (torpedograss).
Melaleuca is an Australian tree that was first introduced into South Florida in the early 1900s. Since that time it has rapidly invaded many natural areas in the region, creating dense monocultures th at displace native plant co mmunities and alter wildlife value of the habitat. Melaleuca originallywas planted in Lake Okeechobee by the USACE in the late 1930s and early 1940s. These fast growing trees were planted on low-lying islands on the side of the lev ee facing the lake to protect th e levee system from wind and wave erosion. Melaleuca has si nce spread to cover thousands of hectares of the lake's littoral zone. Torpedograss is native to Europe, but now occurs in Australia, Asia, Africa, and North America. Torpedograss was introduced into Florida in the 1920s. It gained popularity as a cattle foraging gr ass in the 1950s and was plante d in every county in South Florida. Torpedograss was introduced into th e lake in the 1940s and since then it has expanded to more than 6,000 hectares (ha) inthe northern and western littoral zone. The District has been carrying out an ef fective program to eradicate melaleuca, and is beginning to implemen t a program, in cooperation wi th the FDEP, to control torpedograss. Until now, torpedograss has spre ad unchecked in the lake's littoral zone, displacing valuable native plant communities . Scientists at the District have worked closely with managers to identify the optim al treatment methods for killing the invasive grass. Present efforts are using a combination of controlled fire and the contac t herbicide Arsenal ® . During 2000-2001, the coordinating agencies treated several thousand acres of torpedograss in this manner. A much larger area of the littoral zone will be treated in future years. Because Arsenal ® is a nonselective he rbicide, one issue of concern is how to achieve good control of torpedogr ass while allowing na tive plants to recolonize treated sites. A major focus of exotic plant research in the near future will be in screening alternative herbicides that can more selectiv ely control torpedograss, and in evaluating the potential for use of biocontrol agents against this exotic plant.
The Lake Okeechobee Protection Act (Section 373.4595, F.S.) calls for the identification of exotic plants and animals that occur in the lake and watershed that threaten native flora and fauna, and, where necessary, th e development of control measures. This may result in an expansion of exotic control progr ams beyond their present scope.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

105 

## A. GOALS, OBJECTIVES, AND STRATEGIES
Management goals and objectives de veloped for Lake Okeechobee include provisions for protecting and enhancing the envir onmental resources of the lake itself, and for enhancing the functional role of the lake in the regional ecosystem. The regional system includes the St. Lucie and Caloosahatchee estuaries, the Kissimmee River, and the Florida Everglades. In regard to the lake resour ces, a multifaceted approach is used to provide the most scientifically ri gorous and relevant info rmation to decision make rs. It involves three fundamental and interrelated components: • A systematic progr am of long-term ecological assessment is designed to provide the information necessary to evaluate specific “performance measures.” These performance measur es are used to judge the success of lake restoration pr ojects carried out under the CERP and the Lake Okeechobee Protection Act (Sec tion 373.4595, F.S.) mandates. They also provide the scientif ic basis for making changes in the restoration projects if they are not having the expected effects on the ecosystem (this is the underlying concep t of adaptive assessment). • Issue-oriented experimental research is carried out to address major questions related to management of the resource. Examples include the identification of an optimal lake stage “envelope” for maintaining healthy submerged plant beds, identif ying selective herbicides that can effectively kill torp edograss while not harm ing native plants, quantifying the role that plants a nd animals play in controlling the lake’s phosphorus ass imilation, and evaluati ng how higher trophic levels (e.g., fish and wading birds) respond to reduced nutrient loads and/or changes in hydrology. • Predictive models are being developed and a pplied to address specific management issues. Examples include the use of a lake water quality model for setting a TMDL for phos phorus; use of a lake sediment transport model for identifying the optimal location(s) for lake sediment dredging; and use of a next generation, hydrodynamic, water quality model for predicting effects of CERP project elements on lake water quality, submerged plant distribution and abundance, and phosphorus transport into the littoral zone.106 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT



### Goal 1: Protect and enhance th e environmental resources of Lake Okeechobee, in terms of biological diversity, ecological functions, and th e distribution and abundance of native plants and animals Objective 1: Quantify how variations in lake water level affect the environmental resources, and use this information to set appropriate lake management goals Strategy 1: Quantify relationships betw een lake water levels and the germination, growth, and spatia l distribution of submerged and emergent aquatic plants, and use th is information to identify ranges of lake water levels that are optimal for the native plant communities Strategy 2: Develop and use models to predict how different management actions (e.g., different ranges of water levels under the CERP) will affect the distributi on and abundance of native plant communities Strategy 3: Quantify the relationship between lake water levels and the germination, growth, and spatial distribut ion of nuisance and exotic plants and use this information to identify conditions that will minimize their rates of expansion Strategy 4: Identify wildlife uses (i.e ., foraging and nesting) of native versus exotic plant communities in the lake, and use this information to identify the wildlife benefits that might be realized by different scales of exotic plant control Strategy 5: Identify the cause-and-effect links between lake water levels, nutrient transport among th e lake's major zones (pelagic, nearshore, and littoral), and the impacts of nutrients on the lake's biological communities Objective 2: Develop a predictive understanding of nutrient dynamics in the lake ecosystem, and use this info rmation in support of the CERP and TMDL development process Strategy 1: Quantify the biological processes that affect phosphorus dynamics in the pelagic, nearshore, and littoral zones Strategy 2: Enhance existing lake models to account for important biological processes, and expand the capability of the models to predict responses of major producer communities (phytoplankton, periphy ton, and vascular pl ants) to changes in external and internal nutrient loadingLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

107 Strategy 3: Quantify major links in th e lake's food web and use this information in concert with model output to predict effects of nutrient load reduction on fish, bird s, alligators, and other important animals in the ecosystem Objective 3: Identify exotic species that threaten native plants and animals in the lake and develop and implement programs for their control Strategy 1: Quantify the distributio n and abundance of exotic plants in the lake, iden tify any significant tre nds in their expansion over time, and evaluate their impact s on native plants and animals and/or water quality Strategy 2: Quantify the distributio n and abundance of exotic animals in the lake, identify any significant trends in their expansion over time, and evaluate their impacts on native plants and animals and/or water quality Strategy 3: Develop and implement effective measures to control exotic species that threaten native plants and animals and/or water quality, focusing these efforts on th e control of torpedograss for the next three years Objective 4: Quantify long-term trends inthe lake's ecological values Strategy 1: Develop and implement a program of long-term ecological assessment that is consistent with the ecological attributes and perfor mance measures iden tified in the Lake Okeechobee Conceptual Model (Havens, 2000) and the CERP Strategy 2: Develop and maintain a ge oreferenced database for the long-term ecological assessm ent program being developed, including a user-friendly graphical user interface, comprehensive meta data files, and links to the internet


## B. ECOLOGICAL IMPACTS OF WATER LEVEL VARIATION
Lake Okeechobee is completely encircle d by a dike that eliminates natural connections between the lake and vast marsh ecosystems that once occurred to the north, west, and south (Aumen, 1995; Havens et al., 1996a). Because the littoral zone is constrained to a region inside the dike, r ecent (1994 to 2001) variat ions in water level (from greater than 18 to less than 10 feet NGVD) have caused complete submersion and exposure of the littoral community ( Figure 4-2 ). A long lasting (1994 to 2000) period of high water levels in particular resulted in a number of harmful impacts on native plants and animals. The lake's emergent and subm erged plant communities provide habitat for108 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Figure 4-2. Maps of Lake Okeechobee showing the area of littoral zone that is inundated with water under a variety of lake stage elevationsLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

109 fish (Fox et al., 1993), wading birds (Smith and Callopy, 1995; Smith et al., 1995a), and federally-endangered species li ke the Everglades snail kite (Bennetts and Kitchens, 1997). Therefore, it is important that resource ma nagers understand clearly how changes in water levels affect the lake ecosystem, so that ac tions can be taken to minimize harm. As better information becomes avai lable, it can be used to modi fy existing rules and/or proposed operational criteria, so that they provide the necessary conditions for protecting the ecosystem. A rigorous program of scientific res earch, monitoring, and modeling provides the foundation for these efforts.


### B1. Effects of Water Level on Native Plant Communities Two distinct regions of the lake support native plants ( Figure 4- 3 ) and these generally are considered separately when studying the effects of water level. The littoral
zone is a large region of emergent, submerged, and floating-leaf plants that occurs along the lake's western side and on islands in the southern region. The littoral zone supports more than 50 native plant species, whose distribution can be largely explained by hydroperiod (Richardson et al., 1995). Some species, such as Eleocharis cellulosa (spikerush), Typha spp. (cattail), and Nelumbo spp. (water lily) occur where there is a long (greater than 95 percent) hydroperiod. Other species, such as Spartina bakeri (sand cordgrass) are restricted to shorter (less than 80 percent) hydroperiod littoral regions. A number of approaches are being used to further evaluate the hydroperiod requirements of native littoral plant species, and allow predictions of how the community will respond to changes in lake stage operations. District scientists maintain GIS ma ps of the vegetation and correlate these with antecedent hydroperiod conditions. The entire littoral zone is photographed at five-year intervals with 1:24,000 aerial photography, and fr om this informatio n GIS maps are made for dominant species of native plants ( Figure 5 ). A complete littoral zone vegetation map is constructed approximately once each decade, unless some event occurs to change the large-scale distribution of plants (e.g., in 1989 and 2000-2001 fires burned most of the Figure 4-3. Areas of Lake Okeechobee that support distinct primary producer assemblages, determined largely as a function of water depth110 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Figure 5. Four dominant vegetation communities in Lake Okeechobee’s littoral zone based on 1996 aerial photographsLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

111 littoral plant community). The utility of ne w technologies (e.g., hyperspectral remote sensing) also will be evalua ted, as they become available. More focused experimental studies also are being done to identify th e optimal hydroperiod for particularly important species. For example, research is being done in partnership with the USACE Waterways Experiment Station to quantif y the optimal hydroperiod for spik erush, a critical foraging habitat for snail kites. The second region of Lake Okeechobee wher e vascular plants can occur is the nearshore zone ( Figure 4-3 ), which occurs at a lowe r elevation (deeper water), immediately adjacent to the littoral zone. The near shore zone can support beds of Potamogeton illinoensis (peppergrass) and Vallisneria americana (eelgrass). It also includes areas at the southernend of the lake with “law ns” of a branched macro alga ( Chara ) and a narrow band of Scirpus californicus (giant bulrush) runni ng parallel to the western lakeshore. Bulrush pr ovides important hab itat for sport fish (Furse and Fox, 1994) and it may act as a wave barr ier to protect submerged plant beds that develop behind it. Plants in the nearshore zone were severely impacted in the late 1990s when water levels in the lake frequently were in excess of 16 f eet NGVD and never fell below 13 feet NGVD for a long duration. In 1998, a record high water level of 18.4 feet NGVD occurred. ( Figure 4-1 ). The ecological impacts caused by high water levels are still being studied. Some effects are documented in 1) a study of Chara performed by Steinm an et al. (1997), showing that abundance of this species declined to near zero when high lake stages occurred; and 2) remote sensing of bul rush conducted by Hanlon and Brady (2000), indicating that possibly a larg e part of former coverage was lost during the high water years ( Figure 5 ). Studies of Chara and bulrush are ongoing, and they will continue to provide information regarding the impacts of water level on the nearshore plant community.

8 10 12 14 16 18 20

1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001Stage (ftNGVD)

Figure 4-1. Plot of monthly averaged water levels in Lake Okeechobee from 1973 to 2000112 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

The District also initiated a program deal ing with submerged va scular plant beds in the spring of 1999. On a quarterly basis (or more often) the dry weight biomass (the amount of living matter) and sp ecies composition of submerge d plants is evaluated at 42 stations in the nearshor e zone. The stations represent a subs et of sites that were sampled in the Lake Okeechobee Ecosystem Study (Zimba et al., 1995) in the late 1980s and early 1990s. This allows for a comparison of histor ical data. In Distri ct surveys conducted in 1999, plants were found at just seven of the 42 sites, whereas in 1989 and 1990, plants were found at all of the locations because water levels were considerably lower (12 to 13 feet NGVD). Lower water corresponds with more light reaching the lake bottom and increased plant growth. In contrast, the years between 1994 and 1999 were characterized by deep (up to 18 feet NGVD) and turbid wa ter, with potential scouring of submerged plant beds also occurring due to wind and wave action (Havens et al., 2001). Several months after a managed recession operation lowe red water levels to near 12 feet NGVD in the spring of 2000, submerged plants increased rapidly in the lake, and by October 2000, were found at nearly all of the surveyed site s. In tandem with meas urements of plants at the 42 stations, District st aff are evaluating the biomass and composition of periphyton (attached algae) and selected macro invertebrates, both of which play important roles in the food web that supports fish and bird populations. Figure 5. The spatial extent of bulrush along a 14-kilometer region of the littoral zone in 1992 versus 1999. The total number of acres wa s substantially reduced in 1999, although the plants still occurred in the same elevatio n contour of the lake.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

113 In addition to the quarterly surveys, the District is now carrying out annual mapping of the submerged plant community at the end of the summer growing season (September-October). In this program, whic h started in 2000, the entire nearshore region was originally mapped in GIS as a 500 x 500-me ter regular grid. Coordinates of all grid cells are loaded into a field global positioning satell ite unit and scientists collect triplicate samples of submerged plants at every geor eferenced site (more than 1,800 sites were sampled in 2000). Due to the large number of sampling sites, records are taken only of sediment type, water depth, transparency, and the presen ce or absence of each plant species. This study provides out put in the form of GIS maps of the attributes evaluated. Starting in 2001, the spatial resolution wa s reduced to 1,000 meters by 1,000 meters to make the program more cost-eff ective and permit a complete sampling in just one month’s time. These new maps still provide a ve ry high degree of spatial resolution. In 2000, it was documented that th e lake supported approximately 18,000 ha (total) of submerged plants ( Figure 6 ), as compared to a FW C estimate of 1,200 ha in

Figure 6. Results of a yearly program (in this case the summer of 2000) that maps the distribution of submerged aquatic vegetation in Lake Okeechobee. Sampling was conducted in all grid cells shown on this map, working from the shoreline outward until at least two contiguous cells were found without plants. The total area of plants then was determined with GIS. All Species - Total Area 17,750 Hectares114 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
1999. The total submerged native plant covera ge is one of the priority ecological performance measures of th e CERP and is included as one of the 15 key regional performance measures in a ye arly report card to the United States Congress. The output from this project will also be used in the calibration and validation of predictive models that will also draw on in formation obtained in ongoing cau se-and-effect research to identify submerged plant respons es to variations in water depth and sediment type. This overall program is patterned af ter a successful proj ect to reestablish th e submerged aquatic vegetation in Chesapeake Bay (USEPA, 1992).


### B2. Effects of Water Level on Exotic and Nuisance Plants

The littoral and nearshore zones of La ke Okeechobee also support high densities of exotic invasive and native nuisance plants . Exotic invasive plan ts are nonnative species that tend to outcompete native species and become quickly established, especially in areas of disturbance or where the normal hydroperi od has been altered. Na tive nuisance plants are native plants that sp read rapidly under di sturbed conditions and displace more desirable plant communities. In the near shore zone, the prin cipal exotics are Hydrilla verticillata (Hydrilla), Eichhornia crassipes (water hyacinth), and Pistia stratiotes (water lettuce). Hydrilla, a plant th at provides valuable fisherie s habitat (Furse and Fox, 1994), once covered nearly 5,000 ha in the lake (Zimba et al., 1995), but today has been nearly eliminated, perhaps by high water levels in the late 1990s. Its distribution and abundance will be assessed as part of a submerged aquatic vegetation progr am described above. Water hyacinth and lettuce are controlled by contact herbic ide application in a program carried out by the USACE. Effects of wa ter depth on these species have not been elucidated, although the results of a recent investigation by Grimshaw (2000) indicate that the plants may become more widely dist ributed when lake water levels are high. In the littoral zone, the principal exot ic and nuisance plants of concern are melaleuca, torpedograss, and cattail. Based on a GIS map constructed in 1996, these species occupied 1,200, 6,800, and 9,200 ha, respectively. Thes e species occupied only 360, 0, and 7,900 ha, respect ively, when a similar mapping ef fort was carried out in the early 1970s (Pesnell and Brown, 1977).
B2a. Melaleuca
In addition to the GIS ma pping that has been done to quantify the total area covered by melaleuca, experimental research has evaluated the potenti al impacts of water depth on melaleuca invasion and expansion. Lockhart (1995) quantified the germination and growth of melaleuca under a variety of water depths in side large replicated outdoor tanks. She documented that low water levels that expose the soil are necessary for the initial germination of mela leuca seeds, but once established, young plants can grow rapidly under either exposed or flooded conditions. Field obs ervations following a drought and low lake stage (less than 11 feet NGVD in 1989-1990) are consistent with this conclusion. After large regions of the littoral zone were exposed, small melaleuca saplings were found over a wide area where they previ ously did not occur. The plants persisted after water levels increased.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

115 As a result of an ongoing pr ogram to eradicate melaleuc a from the lake (described in greater detail later in th is report), nearly the entire 1,200 ha of that exotic plant's coverage now is characterized as dead. Because large seed s ources may remain outside the lake, some level of maintenan ce control of melaleuca may need to occur even where the resident lake population has beeneliminated. The magnitude of this effort may largely be a function of lake stag e operations, which will determine the availability of sites for successful seed germinat ion. During the 2000-2001 drought, with lake stages falling below 10 feet NGVD and the en tire littoral zone expose d, widespread germination of melaleuca certainly was possibl e, and is being closely monitored so that appropriate actions can be taken. B2b. Torpedograss Probably the greatest existing threat to the native littoral vegetation in Lake Okeechobee is torpedogra ss, which has recently been e xpanding at a rapid rate and has displaced important native plant species such as spikerush and Rhynchospora tracyi (beakrush). As discussed below, District scientists performed research in the late 1990s that identified a method using fire and herbicide to kill torpedograss in heavily infested areas. Research also is bei ng done to assess how environm ental conditions affect this plant’s ability to expand into native communiti es. That work has largely been driven by a need to provide a solid scie ntific basis for the District ’s proposed minimum flows and levels (MFL) criterion for the la ke and other regional ecosystems.
The results to date indicat e that hydroperiod is a major factor affecting rate of torpedograss expansion. Observ ational data indicate that to rpedograss occurs primarily above the 13 feet NGVD elevation contour in the lake, where water depths generally are shallow and the hydroperiod is below 75 pe rcent (Richardson et al., 1995). During a period of relatively low water levels in the summer of 1997, District scientists observed that torpedograss expanded into regions of the littoral zone where it previously did not occur, and that these regions had their soils exposed during the event. District staff is conducting a long-term as sessment program at three different spatial scales to monitor further expansion: • Three one-square kilometer refe rence plots are being photographed (1:4,800 scale infrared photographs) annually, and changes in torpedograss coverage from one year to the ne xt are being quantified with GIS technology. The reference plots encompass a gradient from long (over 90 percent) to shor t (below 75 percent) hydroperiod. • The exact locations of several torp edograss fronts and the interfaces of its expansion into native plant communities are mapped biannually using GPS. • The density of torpe dograss and spikerush st ems are being measured inside a number of fixed one-square meter reference cells, where both plants occur. These cells have variable densities ranging from approximately 50 percent torpedogras s and 50 percent spikerush at a short hydroperiod site to near 10 0 percent spikerush at a long hydroperiod site.116 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

In a recent evaluation of data from the second method (the torpedograss fronts), it was documented that forward expansion rate in creased coincident with low lake stages in 2000-2001, as compared to earlier years with higher stage. In addi tion to these field observations and remote sensing, staff recently has collaborated with scientists from the USACE Waterways Experiment Station in a se t of controlled expe riments to establish cause-and-effect links between water leve l and torpedograss e xpansion. The research examined the ability of torpedograss plant fragments to become established in lake sediments flooded to various de pths. Biologists believe that fragments (sections of roots and/or stems that break off froma mature plant) are the main vector for expansion in this plant species. In the experime nts, Smart et al. ( 2000) confirmed that when fragments were placed into water with a depth greater than 25 centim eters, they could not establish roots or aboveground biomass. However, when establ ished plants were placed into a similar gradient of water depths, theywere able to ma intain a high biomass production even when flooded to 125 centimeters ( Figure 7 ). These results suggest that standing water might prevent torpedograss from invadi ng new areas of the littoral zone, but that once the plant becomes established, it cannot effectively be controlled by lake stage operations. Followup studies, planned for 2001-2003, wi ll evaluate whether water depth affects the ability of fragments to invade existing st ands of native plants (at na tural densities), and also will attempt to confirm the notion that propagation by seeds is notan important vehicle for invasion by this exotic grass.
B2c. Cattail Although cattail is a native species in La ke Okeechobee, its expansion is a concern because it spreads rapidly, di splaces other more beneficial native plants, and it provides poor habitat relative to the sp ecies that it replac es (including spiker ush and sawgrass). As a result of the dense growth form of cattail and its accumulated dead thatch material, little light penetrates the canopy. This results in low oxygen conditions in the water because microbial activity far exceeds the low rates of primary production by periphytic algae (Grimshaw et al., 1997). In Lake Okeechobee, high water levels may indirectly cause the spread of cattail. Expansion has been most pr onounced at the pelagic- littoral interface and along the edges of boat trails l eading into the interior litto ral zone. These are areas that likely receive the greatest input s of phosphorus from the pelagic zone when lake stage is high. The reduced occurrence of high lake stage events once CERP is completed, and the reduced concentrations of phosphorus in the lake water due to CERP and Lake Okeechobee Protection Program ac tivities might result in reduced rates of cattail expansion. However, this is many years in the future. In the short term, research has shown (Aumen and Wetzel, 1995) that one ef fective approach for reducing the rate of cattail expansion may be prescribed fires. Wh en flooding occurs shortly after a fire, the recovery of cattail app ears to be low. Even if this does not occur, fire can remove large amounts of dead thatch material and allow for a greater light penetration inside recovering cattail stands.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

117 Figure 7. Total amounts of biomass accrual during a controlled experiment that exposed torpedograss to various water depths: a. biomass accrual for plant fragments attached to the sediment surface, and b. biomass accrual of established plants subjected to the same range of depth treatments (Smith et al., 2002) 0 50 100 150 200 250 300 350 400

-5 0 15 25 50 75 100 125 Planting Depth (centimeters)Biomass (grams) Below ground Above ground 

## a. Fragments

0 50 100 150 200 250 300 350 400

Initial -5 0 25 50 75 100 125 Planting Depth (centimeters)Biomass (grams) Below ground Above ground 

## b. Established118 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT



### B3. Wildlife Use of Native an d Exotic Plant Communities Hundreds of species of animals includi ng birds, fish, mammals, amphibians, reptiles, and invertebrates utilize the pl ant communities found in Lake Okeechobee's littoral zone for nesting, fo raging, feeding, and shelter (C hick and McIvor, 1994; Aumen and Wetzel, 1995; Havens et al., 1996b). The rapid expansion of exotic vegetation throughout many areas of the littoral zone, and the resulting lo ss of tens of thousands of hectares of native plant communities has rais ed concerns that the habitat quality of the ecosystem has been degraded. However, th e quantitative data supporting this view is limited. In order to protect and enhance valu able wildlife habitat, a thorough evaluation of wildlife species diversity and habitat use of both exotic and na tive plant communities should be conducted. A longer- term assessment of the distribution and abundance of key animal species, as described in the Ecological Impacts of Exotic Species section, is also needed. In the five-year Lake Okeechobee Ecosystem Study (1988-1992), wading bird use of distinct vegetation types was considered by University of Florida scient ists, and it was documented that certain native vegetation (e.g., willow) offers optimal nesting or foraging habitat (Smith and Callopy, 1995; Smith et al., 1995a). In anothe r study, scientists at the Florida Game and Fresh Wate r Fish Commission (now ca lled the Florida Fish and Wildlife Conservation Commis sion) documented that peppergrass, eelgrass, and bulrush provide good habitat for sport fish (Furse and Fox, 1994). A particularly high biomass of fish occurred in hydrilla, a submerged aquatic exotic. The USACE recently completed a survey of reptiles and birds in spikerush, torpedograss, and cattail habitats of the lake. However, due to problems with sampling during high water periods, the s hort-term nature of the study (two years), and the location of survey quadrants in sites that were not char acteristic of the larger habitats, the results are inconclusive (USACE, 1999a). A more co mprehensive study is needed in order to quantitatively assess the habitat value of na tive and exotic plan t communities and make predictions about ho w hydroperiod-related changes in plant community structure will affect important populations of animals in the ecosystem.


### B4. Links between Water Leve ls and Nutrient Transport It is difficult to separate out the eff ects of water levels from those caused by excessive nutrients in Lake Ok eechobee, because the two fact ors are strongly interrelated. Therefore, some mention of nutrients is appropriate under this section of the plan, although the issue is described in Chapter 3 . High water levels have been shown to result in greater amounts of phosphorus in the water column, especially the ecologically important nearshore zone. This issue is de scribed in the Lake Okeechobee Action Plan (Harvey and Havens, 1999) and documented in peer reviewed literature (Canfield and Hoyer, 1988; Havens, 1997). Th e possible mechanisms also have been described. These mechanisms include 1) higher water levels allow for greater transport of phosphorus-rich sediment material from midl ake to the nearshore zone (Maceina, 1993); and 2) higher water levels favor dominance of phytoplankton over plants and this allows more of the phosphorus to remain in the wa ter column (Phlips et al., 1993a). As a result of these processes, it also has been obs erved that when water levels remain relatively low (14 to 15Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

119 feet NGVD annual average) the lake has distinct ecological zones (Phlips et al., 1993b). This includes a relatively nutrient-poor nears hore region where light penetration in the water column is high and where nutrients limit the growth of phytoplankton; and a nutrient-rich, turbid, central region where light is most of ten the limiting factor. When water levels are higher (as inrecent years), conditions are more homogeneous, with high concentrations of nutrients in both the ne arshore and midlake re gions and high lakewide turbidity. At very high water levels (greater than17 feet NGVD) p hosphorus-rich pelagic water is transported into the interior littoralzone, where it may bri ng about changes in the abundance and composition of periphyton and perhaps stimulat e the spread of cattail. The impacts on periphyton have been considered with controlled mesocosm experiments (Havens et al., 1997) and are being further ev aluated in a long-term research project on periphyton status along a natural elevation grad ient in the littoral zone. In addition, an existing model of lake water ci rculation and transport is bei ng modified to include a water quality component. Once this is done, the model can be used to predict how different lake operation schedules might affectphosphorus and other chemical transport into the littoral zone. When coupled with result s from scientific investigati ons of the littoral food web it will be possible to make predictions of impacts at higher trophic levels.


## C. ECOLOGICAL IMPACTS OF NUTRIENTS
The biological communities of Lake Okeechobee have b een dramatically impacted by excessive inputs of phosphorus and nitrogen (Havens et al., 1996a). The composition of benthic macro invertebrates has shifted toward pollution-tole rant species (Warren et al., 1995). The biomass of cyanobacteria (blue-green algae) has increased relative to diatoms and other algal groups (Cichra et al., 1995), and algal blooms have become more frequent (Havens et al., 1995a). The blooms are li nked with high phosphorus concentrations, especially in the nearshore region (Walker and Havens, 1995; Havens and Walker, 2001). Because of the long history of excessive nutrient inputs, the lake 's mud sediments also have accumulated large quantities of phosphorus (greater than 30,000 metric tons in the upper 10 centimeters) and sedi ment-to-water fluxes of phos phorus exceed the external inputs on an annual basis (Olila and Reddy, 1993). B ecause dissolved phosphorus concentrations often exceed the requirements of the algae, thei r growth rates generally are limited by other factors, in pa rticular light and nitrogen (Aldridge et al., 1995; Phlips et al., 1997). The high frequency of nitrogen limitation ha s favored dominance by cyanobacteria, including species that form surface blooms (Smith etal., 1995a; Havens et al., 1998). As a result of these harmful impacts, considerable efforts have been made to reduce the external phosphorus loading to Lake Okeechobe e (Steinman et al., 1998) and lake managers continue to explore new appr oaches for further reducing the loads, both external and internal to the lake ecosyst em. Because the management actions can have dramatic economic and ecologica l effects (Havens et al., 1996a), it is critical that they have a solid foundation in science and engin eering. In regard to ecological responses, good information now exists regarding certainecosystem properties, such as phosphorus120 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
geochemistry in the pelagic region (Reddy et al., 1995; Moore et al., 1998), but other potentially important aspect s of phosphorus dynamics are not fully understood. In the following section, the focus is on the potential role that plants and animals may play in the lake's phosphorus dynamics. Othe r aspects are considered in Chapter 3 of this plan. 

### C1. Biological Processes Affecting Phosphorus Dynamics The recently completed Lake Okeechob ee Phosphorus Dynamics Study (Reddy et al., 1995) and othe r research projects cond ucted on this and other shallow eutrophic lakes, show evidence that biological in teractions play an important role in the internal cycling of phosphorus. Important biological interactions may include, butare not limited to, the following: 1) competition for dissol ved phosphorus among phytoplankton, periphyton, and vascular plants in the nearshore zone; 2) suppr ession of wind-driven sediment resuspension by benthic plant assemblages in that same lake regi on; 3) bioturbation of pelagic mud sediments by macr o invertebrates and fish; 4) uptake and sedimentation of phosphorus in the plankton; and 5) vertical migr ation of bloom-forming cyanobacteria. The extent to which these processes occur ma y affect the lake's capacity to assimilate phosphorus (i.e., remove it from th e water column into sedime nt storage). As such, the biological processes ar e directly related to the esta blishment of a ppropriate phosphorus loading targets such as the TMDL. Because the FDEP has proposed that the lake’s phosphorus TMDL be “revisited” at five-year intervals and possibly modified as more information becomes available about the ecosystem, understandi ng the role of biota in the phosphorus cycle is critical. Ha vens and Schelske (2001), fo r example, note that some of the changes that are expected to occur in a recovering lake (reduced cyanobacteria dominance, increased submerged plants, change s in benthic macro invertebrate species) might increase the lake’s phos phorus assimilation, and allow fo r attainment of the in-lake phosphorus goal of 40 μ g/l at a higher rate of extern al loading than presently is anticipated. Walker and Havens (2001) also note that a better understanding of how particular concentrations of phosphorus aff ect plant and animal co mmunities is needed so that the in-lake phosphorus goal can have a mo re holistic foundation, rather than being set only on the basis of algal blooms, as presently is the case. C1a. Competition for Phosphorus Both observational (Scheffer et al ., 1994) and experimental (Confer, 1972; Hansson, 1990) studies have revealed comp etitive interactions between phytoplankton and benthic producers in shal low lakes. Most of the publ ished research deals with temperate lakes, but recent studies indicate that similar interactions occur in the nearshore zone of subtropical Lake Okeechobee. Phlips et al. (1993a) was the first to suggest that this was the case, when they documented th at a midsummer low in phytoplankton biomass corresponded with maximal biomass of epiphtyon and submerged plants. Havens et al. (1996c) performed in situ nutri ent-addition studies in the nearshore zone and found that the phytoplankton and periphyton were limited by the same nutrients (most often nitrogen and phosphorus colimitat ion), confirming the potential for nutrient competition. Most recently, Hwang et al. (1998) documented that conditions in the nearshore zone could favor phosphate uptake by eith er phytoplankton (during d eep water periods with poorLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

121 transparency) or periphyton (during shallow periods with high transparency). Data collected during the recent lake recession operation, wherein the lake stage dropped to near 12 feet NGVD in th e summer of 2000, are supportive of the role that plants can play in controlling water column phosphorus. Prior to the recession operati on, when lake stage was near 15 feet NGVD, nears hore waters were turbid, devoi d of plants, and had total phosphorus in excess of 100 μ g/l. Within weeks of attaini ng the low stage level in the spring of 2000, nearshore areas developed clea r water, vast lawns of submerged plants (primarily Chara spp.), and total phosphorus concentrations below 30 μ g/l. Nutrient dynamics in the central pelagi c region are less complex, because the greater water depth and reduced light penetration are not su itable for benthic plant and periphyton communities. In the littoral zone, the greatest quantities of phosphorus occur in the periphyton community, because high transparencies occu r regardless of lake stage (Havens et al., 2000). This periphyton has a tremendous capacity to remove phosphorus from the water column, as documented in c ontrolled mesocosm studi es by Havens et al. (1997). After adding 800 μ g/l of soluble phosphorus to en closures over a period of 28 days, water column phosphorus conc entrations remained below 30 μ g/l. At the same time, concentrations of phosphorus in peri phyton tissues increased significantly( Figure 8 ). These results do not mean that phosphorus inputs cannot have nega tive effects on the indigenous community. In the same study, th e authors observed dram atic changes in the taxonomic composition of periphyt on after weeks of high nutri ent loading. Similar to what has been observed in the Florida Everglad es (McCormick et al., 1996), the periphyton shifted toward dominance by large filame ntous green algae that are not a good food resource for invertebrate grazers. Havens et al. (1997) noted that the li ttoral periphyton in Lake Okeechobee was colimited by nitrogen and phosphor us, rather than by phosphorus alone as it is in the pristine central Everglades. They hypothesized that the litt oral periphyton community has been impacted by phosphorus i nputs to that region that occu r during periods of high water level. Ongoing research is being done to confirm the vali dity of this hypothesis. This includes a multiyear study of periphyton taxonom ic structure and nutrient limitation along transects where water moves into the littoral zone. During periods of high stage we expect to see a shift towards taxa more indicative of eutrophic conditions, especially at sites closest to the open water zone. When combin ed with results of controlled mesocosm studies, this information can be used to cal ibrate models to pr edict how the littoral community will benefit from reduced phosphorus transport associated with new CERP lake stage operations and lowe red external phosphorus loads.
C1b. Sediment Stabilization The large reservoir of phosphorus stored in the sediments of Lake Okeechobee can serve as a net source of phosphorus to the water columnvia resuspension and diffusion (Olila and Reddy, 1993). Howeve r, in nearshore areas, be nthic plants can reduce this resuspension because their roots physically bind sediment s and their morphology presents a physical barrier to shearing stress on the sediment surface. Pl ants also can change the pH and dissolved oxygen status of surrounding wate r and this can affect diffusive phosphorus transport. If sediment stabil ization ever does come into play, it most likely would be122 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFTa. Water Column Phosphorus02004006008000 100 200 300 400 500 600 700 800Phosphorus Added (μg/l)

Phosphorus Measured ( μ g/l)b. Surface Mat Phosphorus02004006008000 100 200 300 400 500 600 700 800Phosphorus Added (μg/l)

Phosphorus Measured (mg/kg)c. Epiphyton Phosphorus05001000150020000 200 400 600 800Phosphorus Added (μg/l)

Phosphorus Measured (mg/kg)d. Metaphyton Phosphorus02004006008000 200 400 600 800Phosphorus Added (μg/l)

Phosphorus Measured (mg/l)

Figure 8. Total phosphorus concentrations measured during a controlled mesocosm experiment in the littoral zone after adding various am ounts of phosphorus over a 28-day period : a. water column concentrations, b. surfac e algal mat concentrations, c. epiphyton concentrations, and d. metaphyton concentrations (Havens et al., 1997)Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

123 during years with very low wa ter levels, when submerged pl ants can extend for several kilometers offshore (Zimba et al., 1995). In th e late 1990s, following several years of high water level, submerged plants were restricted to areas just adjacent to the littoral zone and their role in affecting sediment-waterphosphorus exchanges probably was minimal. However, as indicated above, submerged plants increased dr amatically in the summer of 2000 when lake stage was lowe red, and were concomitant decreases in phosphorus and suspended materials were recorded in the wa ter column of the nearshore region. In the longer term, a considerably lower water leve l regime is anticipa ted under the CERP. Research and modeling are needed to predic t the impacts of more widespread plant growth on water column total phosphorus , because the effects noted above might determine, in part, a more appropriate l ong-term phosphorus TMDL than has recently been proposed. C1c. Sedimentation of Phosphorus in Plankton One of the main loss proces ses for phosphorus from the water column of lakes is settling of phytoplankton cel ls, zooplankton, and zooplankt on fecal pellets. The Lake Okeechobee Water Quality Model estimates sedimentation rate based on paleolimnological data from lake sediment cores (Brezo nik and Engstrom, 1998). Given that it represents an importa nt loss process in that model, more direct measurements of these rates and how they vary with envir onmental conditions (e. g., wind, current) are needed. Furthermore, it is imp ortant to determine how the ne t settling rate is affected by the taxonomic composition of th e plankton. Present sedimentat ion rates may be low as a result of dominance by small species of cyanobacteria, but the rates could increase substantially if diatoms beco me dominant (Havens and Schels ke, 2001), as they did in the mid-1970s (Marshall et al., 1977). Anticipate d benefits of meeting the TMDL include reduced in-lake total phosphor us concentrations, an incr eased frequency of phosphorus limitation, and a decline in cyanobacteria relative to diatoms. The increased settling rate of diatoms relative to cyanobacteria could result in a greater net assimilative capacity of the lake for phosphorus. Furthermore, under phos phorus deficient conditions, a greater portion of the water column to tal phosphorus is exp ected to occur in algal cells (as opposed to the soluble phase) and this could further contribute to sedimentation (Havens and Schelske, 2001). The extent to which algal cells are grazed by zooplankton and subsequently repackaged into larger, more readily settled, partic les also may change. These processes may have a direct bearing on the lake TMDL, and as such, need to be supported by quantitative scientific information.
C1d. Bioturbation The burrowing and feeding activities of be nthic invertebrates and fish can recycle nutrients from lake sediments to the overl ying water column, and in shallow eutrophic lakes these fluxes can account for a large fraction in the lake's internal phosphorus load (Schaus et al., 1997). In Lake Okeechobee, sedi ments of the central pelagic zone contain high densities of oligochaete worms, and Van Rees et al. (1996) reported that their activities resulted in sediment to water phosphorus fluxes that were two to 15 times greater than in sediments without the animals. Research sti ll is needed to determine how these phosphorus flux rates compare to those occurring when the lake's invertebrate124 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
community is dominated by chironomids and other taxa less indi cative of polluted conditions. We also have no information about th e role of fish bioturbation in this lake. Because the fish assembla ge contains a high dens ity of gizzard shad ( Dorosoma cepedianum ), which is known to recycle large quant ities of sediment phosphorus in other shallow lakes (Vanni, 1996), this proce ss merits evaluation. The information is particularly important in the context of setting a TMDL for phosphorus because, under conditions of reduced external loading, changes in both the benthic invertebrate and fisheries communities may occur. Reductions in the relative biomass of oli gochaetes and gizzard shad could be expected to contribute to reduced internal loading and increased net phosphorus assimilative capacity(Havens and Schelske, 2001). C1e. Cyanobacteria Vertical Migration and Nutrient Utilization Vertical migration of cyanobact eria from the lake sedime nts to near the surface of the water column may be a another important pathway for phosphorus transport in Lake Okeechobee, as it is in other shallow lakes (Takamura et al., 1992). Based on multivariate statistical analysis of phyt oplankton and water quality da ta collected in the Lake Okeechobee Ecosystem Study, Havens et al. (1998) developed a conceptual model of algal bloom dynamics for the lake ( Figure 9 ). Blooms are triggere d during prolonged calm periods when two events may occur: 1) an anoxic (greatly deficient in oxygen) or hypoxic (deficiency of oxygen reaching animal plant ti ssues) layer develops at the sediment-water interface, allowing soluble phosphorus to ente r the water column wher e it can be taken up


### (a) Turbid Conditions (b) Calm Conditions

Wind mixing and no sustained vertical heterogeneity of algal biomass Light Light

Lyngbya , Oscillatoria ,other nonnitrogen-fixers adapted to low irradiance Carbon Dioxide (CO 2 )

Phosphate

Dissolved Inorganic Nitrogen Cynobacteria
Cynobacteria 

### BLOOM

Anabaena , Microcystis , other nitrogen-fixers that require high irradiance Stable water column, vertical migration, sustained surface biomass maximum

Phosphate Nirogen (as N 2 )

Carbon Dioxide (CO 2 )

Dissolved Inorganic Nitrogen

Figure 9. A Conceptual model of algal bloom dynami cs in shallow eutrophic lakes (Havens et al., 1998)Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

125 by cyanobacteria colonies; and 2) bl oom-forming cyanobacterial species (e.g., Anabaena and Microcystis ) that require high light levels for optimal growth migrate to the water surface, forming the visible surface blooms that have been such a major concern in this shallow lake. Because the cyanobacteria can obtain nitrogen and carb on from atmospheric sources, they are essentially unlimited in their growth during such calm periods. This model still needs to be validated by results fr om controlled experiment s. In particular, the rates of upward phosphorus tran sport should be quantified and the vertical migration process incorporated into lake water quality models. Under most circumstances, the phytoplankton in Lake Ok eechobee is more limited by nitrogen than phosphorus (Aldridge et al., 1995), and, ther efore, an understanding of nitrogen cycling also is necessa ry for accurate predictions of lake responses to changes in external nutrient loading. At this time we know very little about nitrogen dynamics in subtropical lakes. Only two processes, planktonic nitroge n fixation (Phlips and Ihnat, 1995) and denitrification (Messe r et al., 1979), have been directly measured in Lake Okeechobee, the latter being st udied over 15 years ago, when nu trient concentrations were much lower than at present. No studies have been conducted to measure rates of nitrification or minera lization, yet these processes are in cluded in the water quality model that is used to predict algal responses to external load re ductions (James et al., 1997). The water quality model uses parameter values taken from the published literature on temperate lakes, and these rates may not be applicable for subtr opical Lake Okeechobee. A pilot study in the summer of 1996 (Gu et al., 1997) provided some information concerning planktonic al gal uptake rates for nitrate, nitrite, ammonia, urea, and N 2 (the various dissolved forms of th is nutrient), but additional st udies of a broader scale are needed to fill this information gap. 

### C2. Development and Applicati on of Predictive Models The use of models for predicting lake responses to mana gement actions is described in detail in Chapter 3 of this plan. Here, the focu s is on incorporating additional aspects of the lake biology into the models and on extra polating model predictions to higher trophic levels. The lake water qualitymodel presently in use is based on the USEPA Water Quality Analysis Simulation Package (WASP). However, the Lake Okeechobee Water Quality Model has been modifi ed to 1) make predictions regarding the biomass of three algal groups, diatoms, chlorophytes, and cy anobacteria; 2) include the silica cycle; 3) consider five ecologically distinct regions of the lake; a nd 4) allow linkage with a three-dimensional hydrodynamic model and a sediment transport model (James et al., 1997). Sensitivity analysis indicates that model refinement should include better (lakespecific) information about al gal settling rates, as noted above. Furthermore, the model appears to be lacking some of the processe s that vary with lake stage and drive the observed linkage between wa ter levels and phosphorus assimilation. Preliminary work with a relatively simple phosphorus mode l (based on the Stella modeling platform) suggests that by including submerged aquati c vegetation related processes in the model, long-term predictions of lake response to CERP could be substantiall y improved. This will be one focus of model refine ment during the next three ye ars. The work will largely depend on the results of observational and experimental subm erged plant research being126 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
done by District scientists. To effectivel y use a model that includes a vegetation component, however, it will be necessary to modify the Lake Okeechobee Hydrodynamic Model to include water qual ity and light attenuation comp onents, and then link this model’s output with the Stella model of submerged vegeta tion. This linked model could produce maps showing submerge d vegetation distribution unde r different lake stage or nutrient loading scenarios, and as such, beco me a valuable tool for managers. The model also could address effects of water and nutrient input to the littoral zone, by making use of results from controlled experi ments to identify how the li ttoral landscape (plants and animals) responds to different depth and nutrient input conditi ons. This is a long-term goal beyond the three-year horizon of this SWIM planning docum ent, but model development and experimental data collec tion in the next three year s can provide much of the information needed to achieve that goal.


### C3. Nutrients and the Lake Food Web It has been recognized for some time thatthe lake's commercial fishery has great economic value, perhaps in excess of $300 million (Furse and F ox, 1994). The lake also plays a critical role as a habitat for mi gratory waterfowl, wading birds, alligators, federally-endangered Everglades snail kites, and numerous other amphi bians, reptiles, and mammals (Smith et al., 1 995a; Bennetts and Kitchens, 1997; USACE, 1999a). Despite this fact, our understanding of the lake food web is quite rudimentary, having been investigated only in a prelimi nary manner based on gut analys es of selected taxa and published feeding relationships from other lakes (Havens et al., 1996b). More recently, the fisheries food web was studied at one littoral site, two nearshore si tes, and two pelagic sites using stable ni trogen and carbon isotope analysis (Fry et al., 1999). Based on this study, it was documented that cer tain fish species migrate betw een the littoral and pelagic zones, and that stable isotope analysis is an effective tool for exploring f ood web structure at a finer spatial and temporal scale than is possible with gut anal ysis. Additional food web data, regarding the linkages between animals and plant habitat and water depth, and results of other experimental st udies will be needed to make accurate predictions of fish, bird, and other animal responses to changes in water depth a nd nutrient loading associated with CERP and TMDL compliance.


## D. ECOLOGICAL IMPACTS OF EXOTIC SPECIES
At least 14 species of exotic plants and a number of e xotic animals are found in the littoral and nearshore zones of Lake Okeechobee. Five of the exotic plants are considered a threat to the ecosystem due to their rapid expansion into areas once occupied by native plants. Melaleuca and torpedogra ss occur in higher elevation re gions of the littoral zone. Water hyacinth, water lettuce, and hydrilla occur in the nearshore areas where there normally is year-round standi ng water. The District, th e FDEP, and the USACE have active programs to control all of these plants except hydril la. The most recently activated program is the one targeting torpedograss.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

127 

### D1. Exotic Plant Assessment and Control As noted previously in the Ecological Impacts of Water Level Variation section
on page 107 , a number of different approaches are being used to moni tor and assess yearto-year changes in exotic plan t distribution and pr ograms have been es tablished for exotic control. The primary focus ha s been on melaleuca and torpe dograss because of their rapid invasion of large regions of the littoral zone. Prior to melaleuca treatment, Lake Okeec hobee had two main ar eas of infestation by that exotic tree. The firs t area encompassed the original plantings along the Herbert Hoover Dike and rim canal tree islands. Large, mature, extremely dense monocultures of melaleuca covered nearly 1,200 ha at those si tes. The second main area of infestation included the shallow marsh regi on of the lake wher e trees spread towards the lake from the original plantings. Melaleuc a infestations in the marsh typically consisted of outlier trees and heads of varying ag es scattered over an area of approximately 10,000 ha. As a result of aggressive manage ment program using herbicid e and biological agents the coverage of live melaleuca has beendramatically reduced in the lake. Torpedograss has invaded over 6,000 ha of the littoral z one and it is continuing to invade new areas adding further stress to the ecosystem. The pl ant occurs primarily in the northwestern region of the lake and around the perimeter of M oonshine Bay, just to the south of Fisheating Bay ( Figure 5 ). As described in detail above, a number of studies are ongoing to evaluate rates of torpedograss expansion in different re gions of the littoral zone, and preliminary studies have been done to characteri ze how torpedograss degrades the quality of wildlife habitat. Additional research is needed in this area. As indicated above, however, a primary focus of research in the near future will be on identification of more effective and sele ctive control methods. Starting in 2000, the District and FDEP began a large-sc ale, multiyear program to eradicate torpedograss from the lake’s littora l zone. The method being used at this time is a combination of controlled fire to burn away the accumulated biomass, followed by application of the cont act herbicide Arsenal ® to the subsequent torpedograss regrowth. This method was shown to provide long-termcontrol of torpedogr ass in field-scale experiments carried out by Dist rict and University of Flor ida scientists. However, the nonselective nature of Arsenal ® and the fact that similar applications sometimes had very different long-term effects rais ed concern about a need for additional herbicide screening. A high priority in 2000-2002 will be to identify herbicides that can provide consistent long-term torpedograss control, while at the same time al lowing native plant species to recolonize treated areas. Research also is needed to determine what environmental conditions (e.g., wet versus dry, presence vers us absence of periphy ton algae) allow for the most effective long-term control. The District also proposes to carry out preliminary (literature-based) evaluati ons of whether potential bi ocontrol agents exist for torpedograss. If this yields positive results, then a recommendation could be made for more intensive investigation using the st ate’s new Invasive Exotic Aquatic Plant Quarantine facility. This line of research was identified as a high priority in the Lake Okeechobee Action Plan (Harvey and Havens, 1999).128 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT



### D2. Identification of Exotic Anim als and Their Ecological Impacts Although a number of exotic animals are know n to occur in the lake, their distribution, abundance, and ecol ogical impacts have been li ttle studied. This does not necessarily mean that those impacts are smal l. For example, scientists at the FWC have suggested that blue tilapia ( Tilapia aurea ) may displace bluegill ( Lepomis macrochirus ), a commercially important fish in the lake, becau se the two species have similar diet habits and nesting preferen ces. Also, the Asiatic clam corbicula ( Corbicula fluminea ) has a high particle filtering rate and the potenti al to significantly reduce the biomass of phytoplankton (Cohen et al., 1984). Larg e micro crustaceans such as Daphnia lumholtzii, which invaded the lake in the early to mi d-1990s (Havens and East, 1997; East et al., 1999), might significantly alter en ergy transfer from algae to fi sh in the lake's food web. A complete census of exotic animals in the lake and evaluations of both their rates of population change over time and their impacts on native species are needed.


## E. LONG-TERM ECOLOGICAL ASSESSMENT
As a part of the CERP, the District, the USACE, and other cooperating agencies are developing plans for long- term assessment of ecologica l responses to the regional restoration project. The first objective of this ef fort is to quantify bene fits in terms of a set of ecological performance m easures (e.g., a reduction in al gal bloom frequency or a decrease in the total number of acres of ca ttail). The second obj ective is to provide feedback that might lead to changes in CERP project cons truction and/or operations. The latter would occur if unexpect ed and undesired changes were occurring in the ecosystem as the project moved forward. This is the concept of adaptive assessment. The Lake Okeechobee Protection Act (Section 373.4595, F. S.) also mandates that long-term monitoring be done to assess responses of th e lake ecosystem to management actions. Prior to these regional programs and le gislative mandates, the District had implemented long-term monitoring of a number of ecological attribut es considered to be important indicators of ecosystem stress from nutrients, wate r levels, and exotic species expansion. At this time the Di strict's program on Lake Okeechobee includes the following elements: • Littoral vegetation mapping carried out at various scales of spatial and temporal resolution to determine hist orical changes in the distribution and abundance of native and exotic plants • Quarterly sampling of submerged pl ants at 42 locations in the lake's nearshore zone • Yearly mapping of submerged plants to determine total aerial extent at the end of each summer growing season • Quarterly sampling of attached alga e at several nearshore (south, west, and north) and littoral zone lo cations (along a depth gradient)Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

129 • Monthly sampling of plankton abundance, taxonomic composition, primary productivity, and nutrien t limitation at five locations corresponding to distinct ecol ogical zones in the open lake • Quarterly sampling of macro inve rtebrates associated with bulrush communities in the nearshore region In addition to the District's programs on the lake, the FWC carries out surveys of benthic invertebrate communi ties, larval fish, and adul t sport fish populations on a periodic basis. At any given time the information obt ained from the Ec ological Assessment Program will allow us to evaluate changes in the lake, and contrast these with past management efforts or societal and natural disturbances in the watershed. The existing Ecological Assessment Program will be integrated with the larger CERP adaptive assessment process, which is based on anecological conceptual model developed by experts from various state and fe deral agencies. The lake model ( Figure 10 ) is presented in a format that is consiste nt with models of other South Florida ecosystem regions. It indicates seven major stressors (ovals) that impact the four identified values (pentagons) of the system by way of a number of pa thways (diamonds and arrows). The Lake Okeechobee Ecosystem Conceptual Model (Haven s, 2000) is largely based on the results of scientific research conducted on the lake in the last decade and summarized in this and previous SWIM plans (S FWMD, 1989a, 1993, 1997a). Research and modeling needs identified in the present plan update are consistent with area s of uncertainty in the conceptual model. The model also is dire ctly linked with quantitative performance measures ( Table 4-1) that are used to judge program success . Annual reports of key performance measures will be submitted by the CERP program to the State of Florida and the federal government. The info rmation obtained in the program also w ill be used in a report to the Florida Legi slature mandated by the Lake Okeechobee Protection Act (373.4595, F.S.). 

### E1. Ecological Assessment Database The information obtained in the long-termecological monitoring program, as well as in other research efforts on the lake , must be maintained in a standardized georeferenced format that is r eadily accessible to scientists and managers. Inrecent years, a database has been develope d to store information coll ected in the Lake Okeechobee Ecosystem Study. The database c ontains a first-generation user interface that now is under development. Work also is unde r way to link the tabular data with spatial data that reside in Arc Info coverages. Also, th e data libraries need to be integrated with the District's research web site so users outside the ag ency can readily acces s both raw data and summary information

.130 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFTMoreresuspendedsedimentsExtremes inhigh lake stageExtremes inlow lake stageExotic & nuisanceplantsExoticanimalsElevated levelsof phosphorus (P)Elevated levels ofnitrogen & ClassI / III chemicalsWaste water discharged fromagricultural, urban, and residentialareas; C&SF ProjectIncreased mud sedimentsdue to nutrient inputs, windwaves, and operation ofthe C&SF ProjectRainfall, evapotranspiration, watersupply deliveries out of the lake,operation of the C&SF ProjectAccidental and purposefulintroductions ofexotic speciesMoreblue-greenbloomsGreaterturbidity, lesslightGreaterwave energy& floodingof marshMoreby-products ofalgaldecayGreaterBOD, anoxia,P releaseIncreaseddeposition oforganicsReducedgrowth ofSAVMoresediment & Pin nearshore &littoralGreaterhorizontalmixingDense growthlow dissolvedoxygenLoss ofhabitat forbirds &alligatorsFormationof nearshore“berm”Impacts onbenthicinverts.MorefrequentfiresLake waterqualityFish & aquaticfaunaSnail kitewading birds &alligatorsNativevegetationmosaicControl programswith herbicide, fire, andbiological agentsWater QualityPerformanceMeasuresFish / FaunaPerformanceMeasuresVegetationPerformanceMeasuresMegafaunaPerformanceMeasuresBenefitsSAV, bulrush,otherplantsReducedsedimentstabilityMoreupward PtransportReducedP uptake fromwaterReducednet P lossto sedimentLoss offorage base(small fish,inverts)Damageto nearshoreemergentplantsDisplacebeneficialnativeplantsLosthabitatfor fish &aquaticbiotaBenefits tonative emergentplantsPossibleeffects on fishmigration

Figure 10. An ecosystem conceptual model for Lake Okeechobee, developed for the adaptive assessment process of the CERP. The model shows linkages between sources (rectangles), stressors (ellipses), ecol ogical processes (dia monds), attributes (pentagons), and performance measures (parallelograms). Note: SAV = submerged aquatic vegetation and BOD = biochemical oxygen demandLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

131 

## F. LAKE OKEECHOBEE’S ROLE IN THE REGIONAL ECOSYSTEM F1. Protection and Management of Rare, Threatened, and Endangered Species

The South Florida Multispecies Recovery Plan (USFWS, 1999) was developed to facilitate implementation of anecosystem approach to fish and wildlife conservation. The multifaceted intent of the pl an was to assist governmental entities, Indian tribes, nonprofit organizations, and others to protect threatened and e ndangered species through the acquisition of lands for habi tat conservation planning, public outreach, and information exchange among South Florida working groups.
The South Florida Multispecies Recovery Plan was prepared to fulfill two initiatives of the South Florida Ecosystem Re storation Plan: 1) rest ore and maintain the biodiversity of native plants and animals in the upland, wetland, estuarine, and marine communities; and 2) recover threatened and e ndangered species. These initiatives will be completed in conjunction with the remain ing South Florida ecosystem restoration objectives that comprise the major components of CERP. All the projects associated with

Table 4-1. List of the ecological performance meas ures associated with the Lake Okeechobee Conceptual Ecosystem Model, arranged a ccording to the four major attributes a Lake Water Quality • Total phosphorus concentration • Total nitrogen:phosphorus ratio • Algal bloom frequency • Diatom:cyanobacteria biomass ratio • Nitrogen versus phosphorus limitation • Water clarity as Secchi depth • External phosphorus loading rate • Net lake phosphorus assimilation • Sediment deposition rate Fish and Aquatic Fauna • Population density and age structure of selected taxa that r epresent major trophic guilds (p iscivores, planktivores,

omnivores, and benthivores) • Abundance of selected pollution-tolerant and “desired” taxa in pelagic and littoral zones Native Vegetation Mosaic • Spatial extent of exotic plants in the littoral zone • Diverse landscape of native plants in the littoral zone • Continuous stands of willow and/or pond apple • Spatial extent of continuous bulrush stands • Spatial extent of submerged vascular plants • Spatial extent of shoreline organic berm Snail Kite, Wading Birds, and Waterfowl • Number of Snail Kite nests within the lake proper • Frequency of large feeding colonies of wadi ng birds in the lake during winter/ spring • Number of nests of great egret, white ibis, snowy egret, and heron • Frequency of large feeding colonies of wate r fowl in the lake during winter/spring a. Source: Havens, 2000132 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

the restoration of South Florida will have substantial effects on fish and wildlife resources in South Florida (USFWS, 1999) . The success or failure of many of the projects could determine the status of other species accordingly. Over 600 species in the South Florida re gion are considered rare or imperiled (USFWS, 1999) and 72 species ar e either federally-listed or protected from take ( Table 4- 2 ). These species include 8 mammals, 13 birds, 10 reptiles, 2 invertebrates, and 35 plants. Most of these species are list ed as threatened or endang ered by the federal government. The mountain lion, peregrine falcon, and Am erican alligator are not biologically threatened or endangered, but are afforded protection from “take” because they are physically similar in appearan ce to listed species (USFWS, 1999). Also included in the list, but not federally-listed, are the whooping crane, which is considered an experimental population, and Johnson’s sea grass, which is under the jurisdiction of the National Marine Fisheries Service.
The South Florida Multispecies Recovery Plan set the following criteria for the classification of species, all of wh ich are based on stochastic modeling:

• Recovered - The species has a 95 percent probability (+/- 0.05 percent) of persisting for at l east 100 years and it is assumed threats to the species have been eliminated or am eliorated and the species has met all other recovery criteria.

• Threatened - The species has a 20 to 90 percent probability of persisting for 100 years, regardless of other criteria.

• Endangered - The species has less thana 20 percent probability of persisting for 100 years, regardless of other criteria. This classification assumes a critical situation. Recovery objectives for all 68 sp ecies, as well as the rest oration of 23 habitats, are included in the plan, as well as specific habitat requirement s. Loss of habitat through land use conversions, wetland draina ge, hydrology alterations, and water quality degradation are often limiting factors for many species. At least 17 of the 68 species included in the recovery plan are dependantupon implementation of the CERP components for survival and recovery, and possibly ma ny others will also benef it significantly as a result.


### F2. Kissimmee River Restoration An important component of the lake’s regional ecosyst em is the Kissimmee River drainage basin. The Kissimmee River drai nage basin accounts for approximately 31 percent of surface water inflows to the la ke (Aumen, 1995), and can have a significant impact on the lake ecosystem. Prior to ch annelization in the 1960s , the Kissimmee River meandered 166 kilometers (km) through a co mplex of 18,000 ha of floodplain wetlands. The river-floodplain ecosystem supported di verse and productive fish and wildlife communities regulated by basin hydrology and channel geomorphology (Toth et al., 1995). Channelization of the river for flood c ontrol severely impacted the biological resources of the basin and diminished the eco logical integrity of the ecosystem (Koebel, 1995).Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

133 Table 4-2. The federally-listed endangered and threatened species of South Florida
Common Name Scientific Name Status b
Mammals Florida panther Puma concolor coryi E Mountain lion Puma concolor T (S/A) Key deer Odocoileus virg inianus clavium E Key Largo cotton mouse Peromyscus gossypinus allapaticola E Key Largo woodrat Neotomafloridana smalli E Lower Keys rabbit Sylvilagus palustris hefneri E Rice rat (silver rice rat) Oryzomys palustris natator ( 0. argentatus ) E (CH) Southeastern beach mouse Peromyscus polionotus niveiventris T West Indian manatee Trichechus manatus E (CH) BIRDS Audubon's crested caracara Polyborus plancus audubonii T Bachman's warbler Vermivora bachmanii E Bald eagle Haliaeetus leucocephalus T Cape Sable seaside sparrow Ammodramus ( Ammospiza ) maritimus mirabilis E (CH) Everglade snail kite Rostrhamus sociabilis plumbeus E (CH) Florida grasshopper sparrow Ammodramus savannarum floridanus E Florida scrub jay Aphelocoma coerulescens T Ivory-billed woodpecker Campephilus principalis E Kirtland's warbler Dendroica kirtlandii E Peregrine falcon Falco peregrinus E (S/A) Piping plover Charadrius melodus T Red-cockaded woodpecker Picoides ( Dendrocopos ) borealis E Roseate tem Stema dougallii dougallii T Whooping crane Grus americans XN Wood stork Mycteria americans E Reptiles American crocodile Crocodylus acutus E (CH) American alligator Alligator mississippiensis T (S/A) Atlantic salt marsh snake Nerodia clarkii ( lasciata ) taeniata T Bluetail (blue-tailed) mole skink Eumeces egregius lividus T Eastem indigo snake Drymarchon corai's couperi T Green sea turtle Chelonia mydas (including agassizi ) E (CH) Hawksbill sea turtle Eretmochelys imbricate E (CH) Kemp's (Atlantic) ridley sea turtle Lepidochelys empii E Leatherback sea turtle Dennochelys coriacea E (CH) Loggerhead sea turtle Caretta caretta T Sand skink Neoseps reynoldsi T Invertebrates a. Source: USFWS, 1999 b. Key: R = Recovered T = Threatened E = Endangered S/A = Endangered or threatened by similarity of appearance CH = Critical habitat XN = Nonessential experimental population NMFS = under the jurisdiction of the National Marine Fisheries Service134 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Schaus swallowtail butterfly Heraclides ( Papilo ) aristodemus ponceanus E Stock Island tree snail Orthalicus reses(not including nesodryas ) T Plants Avon Park harebells Crotalaria avonensis E Beach jacquemontia Jacquemontia reclinata E Beautiful pawpaw Deeringothamnus pulchellus E Britton's beargrass Nolina brittoniana E Carter's mustard Warea carteri E Crenulate lead-plant Amorpha crenulata E Deltoid spurge Chamaesyce ( Euphorbia ) deltoidea spp. deltoidea E Florida bonamia Bonamia grandiflora T Florida golden aster Chrysopsis ( Heterotheca ) floridana E Florida perforate cladonia Cladonia perforate E Florida ziziphus Ziziphus celata E Four-petal pawpaw Asimina tetramera E Fragrant prickly-apple Cereus eriophorus var. fragrans E Garber's spurge Chamaesyce ( Euphorbia ) garberi T Garrett's mint Dicerandra christmanii E Highlands scrub hypericim Hypericum cumulicola E Johnson’s seagrass Halophila johnsonii NMFS Key tree-cactus Pilosocereus ( Cereus ) robinii E Lakela's mint Dicerandra immaculate E Lewton's polygala Polygala lewtonii E Okeechobee gourd Cucurbita okeechobeensis spp. okeechobeensis E Papery whitlow-wort Paronychia chartacea ( Nyachia pulvinata ) T Pigeon wings Clitoriafragrans T Pygmy fringe-tree Chionanthus pygmaeus E Sandlace Polygonella myriophylla E Scrub blazing star Liatris ohlingerae E Scrub buckwheat Eriogonum longifolium var. gnaphalifolium T Scrub lupine Lupinus aridorum E Scrub mint Dicerandrafrutescens E Scrub plum Prunus geniculata E Short-leaved rosemary Conradina brevifolia E Small's milkpea Galactia smallii E Snakeroot Eryngium cuneifolium E Tiny polygala Polygala smallii E Wide-leaf warea Warea amplexifolia E Wireweed Polygonella basiramia ( ciliata var. b. ) E

Table 4-2. The federally-listed endangered and threatened species of South Florida
Common Name Scientific Name Status b

a. Source: USFWS, 1999 b. Key: R = Recovered T = Threatened E = Endangered S/A = Endangered or threatened by similarity of appearance CH = Critical habitat XN = Nonessential experimental population NMFS = under the jurisdiction of the National Marine Fisheries ServiceLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

135 The Kissimmee River Restoration Project includes the continuous backfilling of 35 km (22 miles) of canal, ac quisition of adjacent floodplain lands, removal of two water control structures (S65-B and S65-C), degrading existing floodplain levees, and reconstructing approximate ly 14 km (9 miles) of river ch annel. The project also includes modification of the upper Kissimmee River basin water regulat ion schedule. This will be accomplished by expanding the C-36 and C- 37 canals, which conn ect Lakes Cypress, Hatchineha, and Kissimmee; la nd acquisition to allow additi onal water storage in these three lakes and Tiger Lake; and enlarging stru cture S65 at the outlet of Lake Kissimmee. While the upper basin co mponent provides the necessary fl ows critical fo r restoration of the lower basin river-floodplain ecosystem, more naturally fluctu ating lake levels also will enhance the marsh zones within these lake s and provide improve d fish and wildlife habitat.
In order to assess restor ation success, a Comprehens ive Restoration Evaluation Program has been developed. Th is program takes an ecosyst em perspective and includes hydrological, physical, chem ical, structural, and functional attributes of the system that will best elicit restoration response by all biological communities including river channel and floodplain vegetation, aqua tic invertebrates, fishes , wading birds, waterfowl, amphibians, and reptiles (K arr et al., 1991; Koebel, 1995) . Postrestoration community structure characteristics and f unctional attributes wi ll be compared to baseline conditions and, whenever possible, specific histori cally-based expectations for restoration to determine if communities have changed, if the changes are in the direction and magnitude desired, and whether restorati on goals have been achieved.
Phase I of restoration c onstruction (Koebel, 1995) re sulted in over 12 km (7.5 miles) of backfilled canal. Approximately 2.4 km (1.5 mile s) of new river channel have been excavated, with a total of 24 km (15 m iles) of historic Kissi mmee River reconnected. In addition to backfilling, most floodplain levees in Pool C have been degraded and the S65-B structure has been removed. Within the upper Kissimmee Rive r basin, expansion of the C-37 Canals is expected to be completed in 2003. 

### F3. Environmental Impacts on South Florida Estuaries

Estuaries surround the District’s boundaries and serve several, often-conflicting societal uses. They support co mmercial and recreational fi sheries, comprise important waterways for commercial sh ipping and recreational boating, and often receive processed industrial and municipa l wastes. In addition, estuaries provide flood prot ection, draining rainfall runoff from urban and agricultural land. Estuarie s are important nursery grounds for many commercially-important fish species (SFWMD, 2000b), and contribute significantly to Florida’s economy, quality of life, and environmental well being. Water quality characteristics, inaddition to salinity patterns, af fect community structure and food web organization in coastal systems (Myer and Ewel, 1990). Changes in freshwater inflow patterns (i.e., Lake Okeec hobee releases) have threatened and/or resulted in the loss of critical estuarine habitats and biological communities within District estuaries. The estuarine environment is sensitive to136 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

freshwater releases, and disr uption of the volume, distribu tion, circulation, and temporal patterns of freshwater discharges could pl ace severe stress on the entire ecosystem. The District’s overall goal for the upper east coast and lower west coast estuaries, as presented in the Estuary Research Plan (SFWMD, 1998) is to pr otect, enhance, and rehabilitate estuarine ecosystems. This rese arch plan employs a re source-based approach, that 1) identifies issue-specific manageme nt objectives and 2) pr ovides a framework for the integrated research required to meet these objectives in each estuarine system. The first objective seeks to establish the optimum quantity of freshwater inflow for individual estuaries. The research-management li nk occurs through the development and implementation of CERP and regional water supply plans that incorporate MFLs and PLRGs, which depend, in part , on research that identifies estuarine inflow targets as criteria for allocating water from the connected watershed and retention facilities (e.g., Lake Okeechobee, reser voirs, and ASR systems). F3a. Caloosahatchee Estuary The Caloosahatchee River (C-43 Canal) bi sects the Caloosahatchee watershed and functions as a primary canal that conveys stormwater runof f and regulatory releases from Lake Okeechobee, provides navigation for large boats along the Okeechobee Waterway, and provides recreational opportunities for boating, fishing, and wildlife observation. The estuary provides foragi ng areas and wetland habi tat for a large number of Florida’s rare, endangered, and threatened species (SFWMD, 2000b). Section 373.042, F.S., requires the water ma nagement districts to establish MFL criteria for surface water and aquifers with in their jurisdiction. The minimum flow is defined as the “...limit at whic h further withdrawals would be significantly harmful to the water resources or ecology of the area.” The mi nimum surface water leve l is defined as the “level of surface water at which further wi thdrawals would be signi ficantly harmful to the water resources of the area.” For purposes of establishing MFLs , significant harm is defined as loss of water resour ce functions that take multiple years to recover that result from a change in surface water or ground water hydrology . Through the development of the Lower East Coast Regi onal Water Supply Plan (SFWMD, 2000c), the Lower West Coast Water Supply Plan (SFWMD, 2000d)
, and the Caloosahatchee Water Management Plan (SFWMD, 2000e), and concurrent staff re search and analysis, a methodology and technical basis for establishment of the MFL criteria for the Caloosahatchee Estuary was developed (SFWMD, 2000b). The proposed Caloosahatchee Estuary MF L criteria is based on maintaining freshwater base flows to th e upper reaches of the Caloosah atchee Estuary, which will prevent excessive salinity levels in th e estuary from causi ng significant harm to submerged aquatic vegetation and fish and i nvertebrate communities. Research data were used to relate freshwater fl ow rates to salinity distri butions along the Caloosahatchee River and to correlate biologi cal community responses to varying salinity conditions. These relationships were es tablished for submerged a quatic vegetation, fish, and invertebrates with major emphasis on the sali nity requirements of the freshwater grass, Vallisneria amerciana, commonly known as tape grass or eelgrass (SFWMD, 2000b).Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

137 Tape grass is one of the dominant submerged aquatic plants in the upper Caloosahatchee Estuary, and occurs in well-def ined beds in shallow waters. Vallisneria americana has been identified as important habitat for a variety of freshwa ter and estuarine invertebrate and vertebrate species, including some comm ercially and recreati onally important fish (Bortone and Turpin, 1998). It can also be a food sour ce for the Florida manatee (SFWMD, 2000b).
Excessive freshwater inflows to the es tuary result in imbalances beyond the tolerances of estuarine organisms, while es tuarine biota adapt to, and depend on, natural seasonal salinity fluctuations . Retaining water within upl and basins for water supply purposes can reduce inflows into the estuary and promote excessive salinities. Conversely, the inflow of large quantities of water into the estuary due to flood control activities can significantly reduce saliniti es and introduce stormwater contaminants (SFWMD, 2000b). In order to make informed management decisions, resear ch is being conducted by the District and others to investigate the in situ influence of freshwater inflow and salinity on tape grass to determine if freshwater inflowrequirements are needed to permit a healthy, thriving ecosystem in the uppe r reaches of the Caloosahat chee Estuary. In addition, mapping of submerged aquati c vegetation on the basis of distribution and proximity to significant freshwater input on spatial and temporal vari ations in biotic communities, will provide seasonal fluctuations of submerged aquatic vegetation in the lower parts of the Caloosahatchee estuary, San Carlos Bay, and Pine Island Sound (SFWMD, 2000b). The valued ecosystem component approachapplied to the Caloosahatchee River and Estuary was developed by the USEPA as part of the National Estuary Program. Vallisneria was selected as the valu ed ecosystem component of choice because it requires a number of the primary wate r resource functions that ne ed protection during low flow periods. The District has published several studi es using this resource-based approach to define a preliminary es timate of optimum freshwater flow s that should be delivered to the Caloosahatchee Estuary (C hamberain et al., 1995, Chambe rlain and Doering, 1998a, 1998b). Among the conclusions is that a minimum inflow of 300 cfs will not be harmful to Vallisneria communities and other estuarine biota, however, inflows greater than 2,500 to 3,000 cfs will be detrime ntal to these communities anytim e of the year. A distribution of inflows that has the greatest fr equency of falling within the range of 300 to less that 1,500 cfs, with a peak flow range of 300 to 800 cfs, should be generally beneficial to all biota evaluated. The greatest priority should be given to making the desired delivery in February to ensure that opt imum conditions are available in the spring and the required salinity regime has been established for Vallisneria when it is most needed (SFWMD, 2000b). The health of the estuary is an indicator of the health of the watershed. The loss of important habitat functions, such as young fi sh nurseries and good water quality, as a result of reduced dry season fl ows and increased salinity, have the potential to result in some level of harm to the submerged aquatic vegetation co mmunities and th eir associated fauna within the Caloosahatchee Estuary (SFWMD, 2000b).
Once the CERP facilities ar e operational, the optimal flow requirements for the Caloosahatchee Estuary will be realized, but the estu ary has a high probability of138 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
experiencing significant harm due to the lack of sufficient freshwater flows before the structural solutions that are part of the CERP are completed. In the interim basis, the proposed minimum flow should he lp to eliminate, or greatly reduce, the need to make short-term, high volume releases in the dr y season. High volume releases over short time periods, and limiting boat lockages through the water control structures, are common practices during the dry season to protect municipal water s upply from salt water and/or undesirable algae blooms (SFWMD , 2000b). District staff have identified short-term and long-term approaches to implementing the proposed MFL criteria and protecting the resource from significant harm. F3b. St. Lucie Estuary Historically, the amount of salt water en tering the St. Lucie Estuary varies due to the constantly changing nature of the inle ts along the barrier is land. As a result of increased settlements along the coast and in the western portion of the counties, the amount, quality, and timi ng of fresh water entering the system have been drastically altered. The area, which originally drained slowly by overland flow into the St. Lucie Estuary, increased in size, and the drainage increased in velocity and amount. Salinity is one of the more crucial abio tic factors influenci ng the distribution of organisms in estuaries. Nume rous studies have found that estuary flora and fauna tend to fall into general groups base d on their reactions and tolera nces to salinity, and are classified as such. While organisms are us ually found in one of the classification categories, they can become stressed with syst ems that move from one category to another with varying conditions (Woodwar d-Clyde Consultants, 1998). Some estuarine species, such as the eastern oyster, Crassosterea virginica , have been negatively impacted by the change in flow patterns . Although much is known about Crassastrea virginica from other estuarine systems, the St. Lucie Estuary oysters have not been studied. The wide and varied fluctuation of salinity from stormwater runoff and Lake Okeechobee releases do not allow the current system to maintain a stable population. Oyster growth, development, and reproduc tion depends on the depth of water, the substrate type, salinity, currents, dissolved oxygen, temperature, pH, amount of suspended solids, and availability of food sources. Similar to most sessile estuarine animals, Crassostrea virginica is anatomically and physiologicall y well adapted to a wide range of temperatures, salinities, and dissolved oxygen levels, and capable of surviving environmental extremes as l ong as the conditions do not cont inue for extended periods of time. The American oyster is an almost exclusively estuarine bivalve mollusk with both economic and ecological importa nce (Livingston, 1990). Declines in the oyster harvest are attributable to reduced production due to habitat loss, di sease, and especially extensive closures of the fisher y because of contamina tion by coliform bacteria from inadequately treated salinity wastewater di scharges. The ecological significa nce of the oyster is 1) as a filter-feeding, primary consumer ; 2) as a creator of hard, re ef-like substrates forming a habitat for other organisms; and 3) as preyfor numerous consumer s. Because they are sessile throughout most of th e life cycle, oysters have adapted to a wide range ofLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 4: Environmental Resources

139 environmental conditions and can withstand substa ntial variations in th ese factors. Efforts are under way to evaluate the overall health, survival, and reproduction of the eastern oyster in the St. Lucie Estuary. Research evaluating this species is important in determining water management practices since the District considers the oyster a valued ecosystem component (IFAS, 2000). Few references have been published on submerged aquatic ve getation and oyster distributions in the St. Lucie Estuary. Woodward-Clyde Consultants (1998) produced a literature review of both submerged aquatic vegetati on and oysters and, aside from one survey completed in 1960, most of the inform ation has been anecdotal in nature and consisted of verbal communi cations from local sources with intimate knowledge. The literature review concluded th at all of the submerged aquati c vegetation species evaluated (turtle grass, manatee grass, wild celery, and sago pond) may tolerate moderate current or wave action, while other species have low or unknown tolerances to moderate currents. Appearance of significant na tural ranges of all of the tr ue sea grasses appear to be restricted to a range of salini ties from about 22 parts per thou sand (ppt) to 36 ppt in natural environments (Woodward-Clyde, 1998) . The reviewed literature indicates that all of the sea grasses examined have some short-term (i.e., one to th ree days) low salinity tolerance near 10 ppt and short- term high salinity tolerance betw een 50 and 70 ppt. The distribution of these species in salinities of about 20 ppt appears to be due to the competitive abilities of each species and to other environmental factors, rather than to individual salinity tolerances of each species (Woodward-Clyde, 1998). Based on existing low flow condi tions in the St. Lucie Estu ary, it appears that even with minimal freshwater discharge, the salin ity range for turtle grass, manatee grass, paddle grass, and Johnson’s sea grass, would be too low for these sp ecies anywhere but in the lower estuary. Shoal grass and star grass both appear to tolerate some lower salinities, down to five to 10 ppt on a ca sual basis, and possibly lowe r for short periods (less than three days) (Woodward-Clyde, 1998). The adap tability of the submerged aquatic vegetation for the St. Lucie Es tuary appears to be similar to the current and historical conditions indicating that possibly the alteration of the salinity regime in the estuary may not significantly alter the distribution limits of the species from those currently seen. One possible effect could be more permanent, denser areas of submerged a quatic vegetation (Woodward-Clyde, 1998). Light availability may be the greatest li mitation to submerged aquatic vegetation beds in the St. Lucie Estuary. Period of record data suggest that the es tablishment of sea grass beds may be limited to a very small portion of the estuary unless water clarity is significantly improved, and possibly only brack ish water species may adapt to the amount of light available (Woodward-Clyde, 1998).
F3c. Current Status An update to the Indian River Lagoon SWIM Plan will include developing interim PLRGs in the St. Lucie Estuary and the southern Indian River La goon for nutrients, fresh water, and total suspended solids. The District has initiated storm ev ent monitoring in the St. Lucie Estuary to assist in the PLRG effort. Several Indian River Lagoon SWIM140 Chapter 4: Environmental Resources Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

stormwater retrofit projects are under way in Martin and St. Lu cie Counties that will reduce both the peak flows and sediment load ing, and will enhance the water quality of stormwater runoff entering the Indian River Lagoon and the St. Lucie Estuary. Efforts also include habitat restoration and enhancement as well as environmenta l education projects.
Other efforts for the St. Lucie River wa tershed include projects reviewed and approved in July 1999 by the St. Lucie River Issue Team for implementation within the next five years. In Fiscal Year 1999 1 , $7.5 million was allocated by the State of Florida with the intention of accel erating the progress of wate r quantity, quali ty, and timing improvements through implementation projects in the St. Luci e River and Estuary. The highest ranked projects subm itted were funded and are currently under way. For Fiscal Year 2000, the state has set as ide $10 million to continue funding St . Lucie Estuary projects that were s ubmitted for review by both the St. Lucie River Issue Team and the newly created Florida Water Advisory Panel.

1. The District’s fiscal year begins on October 1 and ends on the following September 30. Fiscal Year 1999 began on October 1, 1999, and ended on September 30, 2000.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 5: Flood Control and Water Supply

141 

## Chapter 5 FLOOD CONTROL AND WATER SUPPLY

Lake Okeechobee is regulated for flood c ontrol and water supply purposes and is the heart of South Florida’ s water management system. During the wet season (June through November), lake levels are regulated to reduce potential flood damages by storing enormous volumes of water. Conversely, during the dry m onths (December through May), stored water is released to support the Ever glades system and to provide water supply to South Florida’s municipal and industrial users, and agricultural ir rigation (Miller, 1999). Since the first attempts to pr otect agriculture, by lowering la ke levels and the construction of canals and dikes, several efforts have been undertaken to serve the multipurpose uses that the lake provides now. Th e subsequent efforts were su mmarized in Table 14 of the Surface Water Improvement and Manageme nt (SWIM) Plan - Update for Lake Okeechobee (SFWMD, 1997a). 

## A. GOALS, OBJECTIVES, AND STRATEGIES Goal 1: Ensure adequate flood pr otection to local communities and agriculture around the lake Objective 1: Upgrade the efficiency and stability of flood control facilities within the Lake Okeec hobee basin and provide for the maintenance and control of aquatic weeds to ensu re project design capacity is met for inflow and disc harge canals and structures Strategy 1: Support the Hoover Dike Ma jor Rehabilitation Project being implemented by the USACE Strategy 2: Maintain design flow and conveyance capacities of the flood control system by continuing the aquatic weed maintenance at inflow/discharge structures and canals, consistent with other lake management objectives Strategy 3: Assist local governments in their comprehensive planning process to address local flood protection needs, consistent with water quality and envi ronmental resource objectives Objective 2: Reduce the EAA’s dependency on the lake for flood control as much as practical Strategy 1: Maintain present reductions in the use of the S-2 and S-3 pumps for flood protection in the S-2 and S-3 basins142 Chapter 5: Flood Control and Water Supply Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT



### Goal 2: Provide a balance between the competing objectives of flood protection, water supp ly, and protection of the lake ’ s marsh zone and do wnstream estuaries Objective 1: As the local sponsor, work actively with the USACE and state agencies in the implemen tation of the WSE Lake Okeechobee regulation schedule Strategy 1: Coordinate meetings/facilities and participate in presentations of the Lake Ok eechobee WSE regulation schedule and adaptive protocols Strategy 2: Provide updated vegetati on maps from the Lake Okeechobee marsh zone (updated regularly) Objective 2: Work as the local sponsor with the USACE to implement the CERP Strategy 1: Cooperate with the USACE on developing new biological data for th e major vegetation communities in the marsh zone of Lake Okeechobee Strategy 2: Collect additional data from the marsh zone of Lake Okeechobee that evaluates the effect of lake stage on the vegetation communities (ongoing) 

### Goal 3: Maintain an adequate quantity of water in Lake Okeechobee to supplement downstream environmental needs and reasonable-ben eficial use requirements Objective 1: Provide water deliveries for use by agriculture and urban communities around the lake and to recharge the coastal aquifer Strategy 1: Define urban and agricultural water supply needs of users that utilize Lake Okeechobee Strategy 2: Continue to implement the current Lake Okeechobee Supply-Side Management Plan (Hall, 1991) for allocation of water deliveries to the EAA during a decl ared water shorta ge as described in the Staff Manual for the Management of Water Shortages (SFWMD, 1987) Objective 2: Provide water supply for supplementing environmental needs through the implementation of the Lower East Coast Regional Water Supply Plan (SFWMD, 2000c)Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 5: Flood Control and Water Supply

143 Strategy 1: Establish environmenta l water needs for Lake Okeechobee, the St. Lucie and Ca loosahatchee Estuaries, the WCAs, and Everglades National Park for the protection of natural vegetation; fish and wildlife habitat; and rare, threatened, and endangered species Strategy 2: Define the role of Lake Okeechobee in meeting the water needs of the downstream environment Strategy 3: Develop a flexible fram ework for managing the operation of the lake at stages below regulation, including the modification of the Lake Okeechobee Supply-Side Management Plan (Hall, 1991) Objective 3: Reduce dependency on Lake Ok eechobee as a water supply for downstream users through implemen tation of demand management and water conservation techni ques and development of alternative sources of water supply Strategy 1: Require that permitted users within the Lake Okeechobee Service Area develop and implement water demand management strategies Objective 4: Augment water supply from Lake Okeechobee consistent with environmental objectives Strategy 1: Investigate methods for de velopment of additional sources of water to the lake that would not advers ely effect its trophic state, marsh zone, or downstream estuaries Strategy 2: Investigate and research al ternative (nonlake) options for supplying agricultural and public water supply demands (e.g., wastewater reuse, industrial and agricultural recy cling, alternate surface water storage facil ities, ASR, and desalination technologies) Strategy 3: Investigate and promote the use of optimization technology on the operation and lo cation of coastal wellfields in order to reduce the potential of saltwater intrusion and, therefore, demands on Lake Okeechobee Strategy 4: As water use permits with in the Lake Okeechobee Service Area come up for renewa l, examine and, if necessary, revise them to insure consistency with the Lake Okeechobee water budget, applicable SWIM and water supply plans, modified regulation schedule, and any othe r identified natural resource management needs of the lake.144 Chapter 5: Flood Control and Water Supply Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT


## B. FLOOD CONTROL
Flood control protects life and property adjacent to Lake Okeechobee. It is achieved in two ways. First, levees completelyencircle the lake except where it connects to high ground on either side of Fisheating Creek. Second, lake stage (water level) is monitored daily by the USACE and the SFWM D, and this information is evaluated according to the lake regulatio n schedule (described in the Regulation Schedule section
on page 5-146 ). The general concept is to ensure that sufficient storage capacity is available for basin runoff and rainfall. Theref ore, the regulation sche dule is at its lowest point before the start of the rainy season on June 1 of each year. The regulation schedule must maintain levels in the lake that are safe in the event of hurricane wind and wave action. Although intense rainfa lls amounting to four inch es or more are common in Florida, serious flooding usually is the re sult of prolonged heavy seasonal rainfall aggravated by tropical storm or hurricane rains.


### B1. Flood Control Canals and the Hoover Dike
B1a. Canals The two major lake outlets, the Caloosah atchee River and St. Lucie Canal, and four smaller agricultural ca nals, the West Palm Beach, No rth New River, Hillsboro, and Miami canals, provide relief for the lake when water levels re ach certain elevations designated by the operational schedule.
The Caloosahatchee River flows westward to the city of Fort Myers, through the Caloosahatchee Estuary, and then into the Gu lf of Mexico. The St. Lucie River mimics the same model on the east coast of Florida; water flows through th e canal to the city of Stuart and then to the St. Lucie Estuary before entering the Atlantic Ocean. During droughts, when water levels are exceedingl y low, releases are restricted to conserve water according to the Lake Okeechobee Supply- Side Management Plan (Hall, 1991). The resulting fluctuations in lake levels have been a bout twice the historical range (Miller, 1999).
B1b. Herbert Hoover Dike
The Herbert Hoover Dike is the earthe n embankment system located along the perimeter of Lake Okeechobee. Components of the dike syst em have been constructed intermittently since the early 1900s, and the lake is now almost encircled by the dike system, with the exception of two portions around the Fisheating Creek inflow where the levees meet higher ground. Th e existing embankments tota l approximately 142 miles in length with typical elev ations of 25 feet above adjacent land elevations. In addition to the earthen embankment, the dike system also includes numerous water control structures along its length. In March 1999, the USACE completed the Herbert Hoover Dike Major Rehabilitation Evaluation Report (USACE, 1999b), which docum ented approximately 10 years worth of levee seepage and stability st udies. The Jacksonville Di strict of the USACELake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 5: Flood Control and Water Supply

145 indicated that seepage and pi ping problems do exist, and the severity of those problems warranted immediate repair meas ures. Analysis of dike reli ability indicated that portions of the dike exhibit unaccepta ble risks of failure at cert ain water levels. The USACE is proposing a solution that involve s the construction of a seepag e berm, with a relief trench and drainage system, along the land side tow of the dike. It will serve as an environmentally-friendly filter that lets the water through without allowing the dike material to pass through with it. The USACE’s analysis and conclusions ha ve been supported by an engineering consulting firm hired by the USACE and a panel of experts (USACE 1999b). The USACE’s rehabilitation is expe cted to cost a total of $160 million dollars to construct. Reach 1, which runs for 22 miles along the southeastern shore, is the highest priority for rehabilitation. The most recent cost estimate for the Reach 1 repair is $78 million. The District has been asked to pa rticipate as a local sponsor of the rehab ilitation project and share the costs. B1c. Backpumping While eight pumping stations provide fl ood protection to basins surrounding the lake, only two of the them ar e considered backpumping st ations: S-2 and S-3. The vast majority of pumping events at S-2 and S-3 have been in support of flood control operations. Backpumping for water supply is used to move runoff from the EAA into Lake Okeechobee for storage and later use to meet demands. Only rarely has backpumping for water supply been used, and hi storically only used in c onjunction with serious droughts that occurred in 1981, 1985, 1989 (Tommy Stroud, 2000, personal communication) and then again in 2001.
The Interim Action Plan (SFWMD 1979), instituted in 1979, was established to reduce phosphorus loading to Lake Okeechobee by diverting a significant portion of EAA runoff south toward the WCAs. The change re sulted in an estimat ed 90 percent reduction of water pumped into the lake from S-2 (between South Ba y and Belle Glade) and S-3 (between South Bay and Clewiston). The Interim Action Plan required improved conveyance capacity in EAA canals to move more water south. B1d. Bolles and Cross Canals Improvements The need for the improvement of the Bolles and Cross canals was identified in all previous Lake Okeechobee SWIM Plans (SFWMD 1989a, 1993, 1997a). Improvements to these canals would allow better movement of water duri ng local storm events and should result in a decrease in intermittent backpumping to the lake. As part of the CERP, the USACE prepared a general reevaluation report and an project environmental impact statement on impr ovements to the Bolles Canal. At this time, these canals will be incorporated into the EAA Reservoir Project.146 Chapter 5: Flood Control and Water Supply Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT 

### B2. Regulation Schedule B2a. Historical Regulation Schedules The C&SF Project originated during a time when flood control, water supply, and land development through dr ainage, were th e primary objectives, and where environmental issues were not a prominen t concern. The Lake Okeechobee regulation schedule determines the timing and quantity of water that need s to be released from the lake when the stage exceeds a certain level, which varies accord ing to season. The most recent lake regulation schedule (Run 25) allowed the lake to peak at 16.75 feet NGVD on September 30. The water stored in the lake is intended for water supply during the dry season. A detailed summary of Run 25 is contained in the Surface Water Improvement and Management (SWIM) Plan - Update for Lake Okeechobee (SFWMD, 1997a). In 1965, the lake regulation schedule was m odified to allow greater storage during the wet season. This was in response to the dry conditions of the early 1960s. After the summer and fall of 1965, a new schedule was developed to help deliver water to Everglades National Park. In May 1992, an al ternative lake regulation schedule, Run 25, was put into effect fo r a two-year period, ( Figure 5-1 ) (SFWMD, 1989). The Run 25

Figure 5-1. The Run 25 Lake Okeechobee regulation scheduleLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 5: Flood Control and Water Supply

147 schedule ranged from 15.60 to 16.75 feet Na tional Geodetic Vert ical Datum (NGVD), with multiple operation zones that varied fl ood releases over a wide range before reaching maximum release rates. The pur pose of this regulation sche dule was to reduce damaging flows to the St. Lucie and Caloosahatchee Estu aries without sacrific ing the flood control or water supply benef its derived from the lake. Run 25 was approve d for implementation in December 1994, and was considered interi m (as are all regulation schedules) because the Flood Control Act of 1968 au thorized an additional four feet of water supply space in the lake. B2b. Current Regulation Schedule Until such time as more permanent solu tions to the environmental restoration efforts under CERP are instit uted, the Lake Okeechobee Regulation Schedule Study is being implemented to improve the environmenta l health of the major ecosystems that are currently declining. The Lake Okeechobee Regul ation Schedule Study was initiated in an effort to optimize the Run 25 regulation schedule for environmental bene fits at little or no impact to the competing purpos es of flood control and wate r supply (USACE, 1999c). The Lake Okeechobee Regulation Sc hedule Study considered four alternative regulation schedules: 22AZE, HSM, Corps 2010, and WSE. An economic study was conducted to determine the net regional and national benefits for the various alternatives. The study determined the WSE schedule ( Figure 5-2 ) represented the best operational compromise to improve the envir onmental health of the major South Florida ecosystems. Implementation of the WSE lake regulation sche dule was determined to not adversely impact water supply, flood control, or existing local or regional economies, and may possibly enhance them through an improve d and more sustainable natural ecosystem and the tourism and small business revenue itis expected to generate (USACE, 1999c). The WSE schedule appears to pr ovide substantial be nefits for the lake littoral zone and marsh. High lake stages, and regulatory discha rges to the St. Lucie Estuary, which have plagued the lake, will be re duced under the WSE. Conditions within the Caloosahatchee system are not expected to substantially imp rove under WSE, or with any of the other alternatives. Flows currently conveyed through the EAA in ex isting canals will continue under the WSE schedule without effecting cu rrent land use or wetlands. WCA-2A and WCA-3A will receive some additional flow, but is not expected to significantly affect regional hydroperiods or existing land or recreational uses.
This new schedule is the first to incor porate climatological forecasting technology as part of the water mana gement decisionmaking proce ss for Lake Okeechobee (USACE, 1999c). A key feature of th e WSE schedule is the lowe r operational zone, Zone D ( Figure 5-2 ), which allows the flexibility to deli ver water to the Everglades during lower lake stages. The WSE schedule allows dry s eason discharges to the estuaries to be gradually increased as necessary to control wa ter levels, and allows more water to be kept in the regional system for water supply and hydroperiod restoration (USACE, 1999c). The District’s Governing Board approve d the WSE schedule in July 2000. It was implemented incorporating th e most up-to-date technical knowledge and tools currently available.148 Chapter 5: Flood Control and Water Supply Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT



## C. WATER SUPPLY
In 1997, the District merg ed its Lower East Coast (LEC) regional water supply analysis of major water storage facilities into the Restudy process. This was a multiyear planning effort with a 2050 pl anning horizon. Analytical tool s, evaluation techniques, and storage projects used in the LEC regional water supply planning efforts completed from 1992 to 1997 were refined for the Restudy anal yses. Technical analyses of the LEC planning area’s future water needs, and the av ailability of water s upplies, indicate that extensive actions are required to ensure th at a sustainable water supply is available to fulfill future urban, agricultural, and natural systems water needs. The Lower East Coast Regional Water Supply Plan (SFWMD 2000e) presents the recommended actions to meet the needs, providing the projects recomm ended in the Restudy are built on schedule. Otherwise, the region will face increased water shortages a nd environmental decline. The recommendations made by the Restudy ar e being implemented through the CERP. Figure 5-2. The WSE regulation scheduleLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 5: Flood Control and Water Supply

149 

### C1. Water Supply Demand Estimates The LEC planning area is expected to ex perience substantial growth between now and 2020, increasing by almost 58 percent form 1995. Most of the increase in population will occur in the coastal areas, which is project ed to have almost se ven million residents in 2020 (SFWMD 2000c). This growth will create additional water demands for potable and irrigation water. The overall wa ter demands of consumptive us ers is projected to increase by 20 percent (SFMWD 2000c). 

### C2. Determination of Natural Areas Water Supply Needs Implementation of the Lower East Coast Re gional Water Supply Plan (SFWMD, 2000c) with its variou s regional water supply development projects wi ll result in a number of major environmental benefits to South Florida’s natural area s. Lake Okeechobee and the St. Lucie and Caloosahatchee Estuarie s will show major improvements by 2010. They should meet their respective planning targets by 2015, due to the implementation of the WSE schedule for the lake and the constructi on of regional water s upply reservoirs within the C-43 and C-44 basins. Cons truction and operation of th e regional storage projects north of the lake greatly reduces the need to 1) make large rel eases of fresh water to the St. Lucie and Caloosahatchee Estuaries and Lake Worth Lagoon during high rainfall years; and 2) meet low flow criter ia proposed to protect these ecosystems during dry periods (SFWMD, 1999b, 2000b) 

### C3. Supply-Side Management Plan
When water levels decline in Lake Okeechobee, the Lake Okeechobee Supply-Side Management Plan (Hall, 1991) becomes activated and water use may be restricted according to the District’s Water Shortage Plan (SFWMD, 1987). This plan provides for phased restrictions on water use that are desi gned to protect the resource from incurring significant harm. When drought conditions are of sufficie nt magnitude that water resources begin to experi ence harm, the District’s Governing Board may require restrictions on operational deli veries and water uses, pursuant to the Water Shortage Rule 40E-21, F.A.C. (SFWMD 2000c) . To meet the existing and future demands on Lake Okeechobee, the stage that triggers supply-side management was lowered by approximately one-half foot. Th e end of the dry season (May 31) stage target was also reduced from 11.0 to 10.5 feet NGVD. 

### C4. Water Conservation Strategies As a result of the implementation of th e Water Supply Policy Document and the regional water supply plan recommendations , many conservation-or iented changes have been incorporated into the District's Basi s of Review for consum ptive water use permit applications. Mandatory water conservation measures incor porated into the District's Basis of Review for water us e permit applicatio ns include water conservation plans for public water supply utilities, and landscape and golf course irrigation projects. Water conservation elements for public water suppl y include irrigation ordinances, Xeriscape®150 Chapter 5: Flood Control and Water Supply Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
criteria, ultra-low volume pl umbing fixtures, cons ervation-based rate structures, leak detection programs, and recl aimed water reuse feasibility studies. For agricultural projects, the Basis of Review provides mandatory irrigati on efficiency standards and requires agricultural demand management m easures including monitoring and reporting of water use. 

### C5. Water Supply Alternatives

Continued use of the tradit ional source of public wate r, the Surficial Aquifer System, can be expanded by in corporating proposed water re source development projects and more efficient use of regi onal and local water s upplies, especially within the coastal areas (SFWMD 2000c and d). Providing additional management of historical sources and through conservation and storage of water, the following opti ons have been identified to make additional water available: • Conservation • Surficial Aquifer System • Floridan aquifer • Reclaimed water • Seawater • ASR • Reservoirs • Surface water The Floridan aquifer appears to be a pr omising source of addi tional potable water in areas with limited access to regional s upplies, without complete knowledge of longterm water quality impacts. Se veral public water ut ilities already us e reverse osmosis technology to remove salt from saline Floridan aquifer water.


### C6. L-8 Diversion

The Lake Okeechobee Technical Advi sory Council recommended the L-8 Diversion Project (LOTAC, 1988). This project has since been incorporated into the Everglades Protection Project. The concep tual design for the Everglades Protection Project included plans for the L- 8 diversion works being operate d to direct runoff from the northern L-8 basin. The water source is prim arily from the Dupuis Reserve and the J.W. Corbett Wildlife Management Area (WMA), and will be di rected to Lake Okeechobee via the S-76 control structure, Culvert 10A, and the new S-309 pump st ation that will be constructed. Analysis of phos phorus loading using the modi fied Vollenweider model (Vollenweider, 1976) indicate s that the long-term loadi ng target is slightly more achievable with this ad ded source of clean water.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 6: Recreation

151 

## Chapter 6 RECREATION

The Lake Okeechobee SWIM planning area has three major recreational areas: Lake Okeechobee, the Okeechobee Waterw ay, and the Kissimmee River. Lake Okeechobee is the largest recreational resource of the region. The lake has one of the most productive freshwater sports fisheries in North America and is an important winter waterfowl observation and hunti ng area. The extensive litt oral zone on the western, undiked side of the lake provides critical habi tat for the lake’s popular sport fishery. The associated waterways and shor eline provide a wide variet y of water-based recreation activities for local residents and out-of- state visitors, includi ng boating, picnicking, sightseeing, camping, swim ming, hunting, airboating, hi king, biking, and horseback riding. Lake Okeechobee experienced six years of inordinatelyhigh water levels during the mid-1990s. These high water levels have caused damage to the native plant populations in the lake and have the potenti al to threaten the fisheries. The Lake Okeechobee Recession was approved by the SF WMD Governing Board by resolution in 2000 was designed to bring Lake Okeechobee to a target leve l of 13 feet NGVD for a period of six to eight weeks inorder for suspended sediments in the lake’s water column to settle out allowing sunlight to reach seed beds in the lake’s bottom. Although signs of new life in Lake Okeechobee were slower thanexpected, many areas showed recovery. The northern portion of the lake remains an area of concern. The Okeechobee Waterway, which stretches 152 miles from Fort Myers to Stuart, links the Gulf and Atlantic co asts of Florida with the lake via the Caloosahatchee River and St. Lucie Canal. The waterway has been used for decades by the Kissimmee Boat-ACade in its oceangoing trips.
Phase 1 of the Kissimmee River Restorat ion Project is completed and has had an effect on recreational activi ties. Although lands acquired for this restoration effort have provided greater opportunities for users such as hiking, hunting, and camping, navigation of larger boats on the restored section of the river is limited and navigation through the entire length of river will be blocked inte rmittently during many phases of restoration construction. The major challenge addressed by this chapter is to manage Lake Okeechobee in order to optimize opportunities for growth of native vegetation to enhance the health of the lake’s fisheries. This challenge will be addressed by using the newly approved WSE regulation schedule for Lake Okeechobee and by working clos ely with other state and federal agencies to avoid, to the greatest extent possible, ex tended high water levels in the future.152 Chapter 6: Recreation Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT 

## A. GOALS, OBJECTIVES, AND STRATEGIES Goal 1: Attain recreational op portunities that meet public demand and are consistent with other SWIM goals Objective 1: Develop and support recreatio nal opportunities within the Lake Okeechobee SWIM planning area to the maximum extent possible considering the environmental sensi tivity and suitability of the area Strategy 1: Assist communities along Lake Okeechobee in developing recreational opportuniti es such as fishing, hunting, camping, hiking, boating, canoeing, bicycling, birding, sailing, ecotourism, and other re lated outdoor activities Strategy 2: Continue recreational de velopment of appropriate lands owned by the SFWMD and s upporting development of other lands within the Lake Ok eechobee SWIM planning area as segments of the Florid a National Scenic Trail


## B. RECREATIONAL ACTIVITIES
The SFWMD and USACE have published several pamphlets of recreational facilities in Lake Okeechobee and the Ok eechobee Waterway, as well as SFWMD land management areas along the Kissimmee River. These have been combined to produce a comprehensive list of recreation sites and their respective activities/public uses in the Lake Okeechobee SWIM planning area ( Table 6-1 ). The recreation sites are listed by county, except for the 27 management ar eas listed under the Kissimmee River Land Management Areas, which incl ude properties acquired by the District for the restoration of the Kissimmee River. In addition to th ese public recreation si tes and land management areas, numerous private fish cam ps, marinas, boat tour, and sightseeing facilities are located near access points to the lake. Addi tional recreational info rmation is available from federal and state agencies, chambers of commerce, tourism development councils, and the SFWMD’s Okeechobee Service Center.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 6: Recreation

153 Table 6-1. Public recreation sites in the Lake Okeechobee SWIM planning area

Recreation Site Recreational Activities a
Boating Fishing Picnic Camping Hunting Biking Hiking Horse Back Martin County Port Mayaca Recreational Area X X (X) A A Port Mayaca Wayside Park X Chancey Bay Access Area X X (X) A A Indiantown Marina X X X DuPuis Reserve X X X X X X X X St. Lucie Lock and Dam X X X X Phipps Martin County Park X X X X X X Okeechobee County Henry Creek Lock Access Area X X Nubbin Slough Access Area X X X Taylor Creek Access Area X X A A Okeechobee (Lock 7/Wayside) X X X A A C. Scott Driver, Jr. Recreation Area X X

Okee-Tantie Recreation Area X X X X A A Glades County Buckhead Ridge X X Indian Prairie Canal Access Area X X (X) X A A

Bare Beach Access Area X X X A A Harney Pond Canal Access Area X XX A A
Fisheating Creek Access Area X X X Nicodemus Slough U U U U Sportsman's Village Access Area X XX
Moore Haven West (Moore Haven Recreational Village) X XX X A A
Moore Haven East (Alvin Ward Park) X XX A A
Ortona Lock and Dam (North) X X X Ortona Lock and Dam (South) X X X Hendry County Clewiston Recreation Area X X X A A COE, Clewiston Port Labelle Marina X Belle Hatchee Marina X Barron Park X Labelle Access Area X X Labelle Lions Park X Lee County Alva Access Area X

a. Key X = Activity allowed at site. (X) = Activity proposed at site. A = Access to Florida National Scenic Trail on Hoover Dike. U = Uses will be allowed once the propos ed construction contract is completed.154 Chapter 6: Recreation Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

W.P. Franklin Lock and Dam North XX X

W.P. Franklin Lock and Dam South X X
Palm Beach County John Stretch Park X X X A A South Bay Access Area X X X A A Belle Glade Recreation Area X X X X A A Rardin Park X X X A A Bacom Point X X A A Pahokee Marina and Campground X XX X A A

Canal Point Lions Club Park X X X A A Kissimmee River Land Management Areas KICCO X X X X X X No Name Slough X X X X X Boney Marsh X X X X X X Bluff Hammock I X X X X X X Bluff Hammock II X X X X X Starvation Slough X X X Oak Creek X X X X Hickory Hammock X X X X X X X Turkey Hammock X X X Cornwell Marsh East X X X X X X X Cornwell Marsh West X X X X X X X X Micco Landing X X X X X Chandler Slough - 1 X X X X X Chandler Slough - 2 X X X X Pearce Homestead Seaboard Marsh North X X X X X Seaboard Marsh South X X X X X River Acres II X Yates Marsh X X X X X X Telex Marsh X X X X X X Platt’s Bluff X X X X X Daughtry Cutoff X X X X X Maple River X X X X X 70 N Marsh X X X X X S-65E Impoundment X X X X X X M-2 Marsh (Part of Paradise Run) X XX X X X

Mims Island (Part of Paradise Run) XX X X X Table 6-1. Public recreation sites in the Lake Okeechobee SWIM planning area

Recreation Site Recreational Activities a
Boating Fishing Picnic Camping Hunting Biking Hiking Horse Back

a. Key X = Activity allowed at site. (X) = Activity proposed at site. A = Access to Florida National Scenic Trail on Hoover Dike. U = Uses will be allowed once the proposed construction contract is completed.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 6: Recreation

155 

## C. SUMMARY OF RECREATION ISSUES
C1. Lake Okeechobee and Okeechobee Waterway

The Lake Okeechobee and Okeechobee Waterway Master Plan (USACE, 1986) identified factors influencing public use, including the existi ng conditions of the project’s recreation resources and require ments needed to meet future demands. The main factor identified was a deficiency of supporting facilities at several areas he avily used for both boat and bank recreational fishing. Crowdi ng at boat launching areas is exacerbated during the busy winter months and during times when the area s are also being used for waterfowl hunting. Also, additional launch ramps are needed to meet the increasing demands for access to the rim canal and Lake Okeechobee. Access to the lake is also affected by water levels and ma intenance of boat trails (see Chapter 7 , which addresses navigation). Other defici encies were identified for camps ites, hiking and bicycling trails, and picnicking facilities. In 1996, recreation levels at Lake Okeechobee were es timated at 64,503,500 visitor hours (Miller, 1999) and fishing and boating pressure continues to increase, particularly in the bay areas and littoral zone, where recreati onal fishing is concentrated. Therefore, it is critical to ma intain adequate recreation facili ties and meet future projected needs. Many impediments prevent th e building of additional f acilities. The USACE may not develop or enhance recreati onal facilities without a cost -sharing sponsor, except those justified to serve other project purposes or for public health and safety (USACE, 1986). Interviews with staff at the FWC reveal that a number of problems are encountered in building boat launch ramps. These include the FWC’s priorities to repair over 200 existing ramps built throughout the state since 1960, the difficulties involved in meeting funding guidelines, and complications that arise when formal written agreements are required between multiple parties, including federal, state, local, and private interests.


### C2. Kissimmee River

The Environmental Restoration of the Ki ssimmee River Feas ibility Report and Environmental Impact Statement (USACE, 1991) identifies impacts to recreation and navigation resulting from restor ation of the Kissimmee Rive r. While acquisition of lands along the Kissimmee River have created a dditional recreational opportunities, including extension of the Florida National Scenic Trail (see the Florida National and Lake Okeechobee Scenic Trails section below), im pacts on general boati ng and recreational boating are anticipated as constr uction of the river restorati on project is completed. Larger houseboats and other deep draf t vessels are not able to navigate within the restored reaches of the river, and water sports, such as water skiing, will be limited to those reaches not included in re storation. This loss will be offset in part by opportunities for canoeists and fishermen using smaller boa ts. Fishing success on the rest ored river is expected to increase over the long term. Navigation issues arising from the Kissimmee River Restoration Project are further discussed in Chapter 7

.156 Chapter 6: Recreation Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT


## D. ONGOING ACTIVITIES
D1. Greater Lake Okeech obee Tourism Alliance In recognition of the ecotourism poten tial of the region, the Greater Lake Okeechobee Tourism Alliance was formed in 1993 to promote a regional identity focusing on the natural scenic beauty and cultural heritage of the area. The Greater Lake Okeechobee Tourism Alliance, which is an ar m of the Florida' He artland Rural Economic Development Initiative, has been active in promoting hiking and bicycling around the Lake Okeechobee Scenic Trail and other areas of the Florid a National Scenic Trail. The alliance recently published a t ourism pamphlet for the eigh t-county region served by the group. The District participated in regional detailed design works hops that provided a forum for communities around Lake Okeechobee to develop master plans that share a common vision. This was a joint effort by the District , local governments, regional planning councils, and gr oups such as Greater Lake Okeechobee Tourism Alliance and the Conservation Fund. The concept was to ensure that community master plans are integrated with regional economic and environmenta l goals. Recreational development was an important component of these workshops.
Annual events on the Herbert Hoover Dike include the Big-O-Go and Big-O-Hike sponsored by the Greater Lake Okeechobee Tourism Alliance and the FTA (FTA). Trail organizers from both groups have been a catalyst for trail development and are instrumental in promoting tourism in the region. The Big-O-Go is a 120-mile, four-day mountain bike marathon that was first held in November 1994. Due to its success and the success of the Big-O-Hike, a nine-day hiking event that ha s taken place every November since 1992, these events are anticipated to drawmore participants in coming years. Both events promote economic growth to the re gion and have gained the cooperation and enthusiasm of communities around the lake.


### D2. Florida National and La ke Okeechobee Scenic Trails

The Florida National Scenic Trail is one of eight national scenic trails in the country. When completed, the trail will meander 1,300 miles through Florida from the Gulf Island Seashore of the Pa nhandle to the Big Cypress Na tional Preserve. Development and maintenance of the Florida National S cenic Trail is being led by the FTA in cooperation with numerous public and privat e agencies, organizations, and individuals. Portions of the trail are within th e Lake Okeechobee SW IM planning area ( Figures 6-1 and 6-2 ). The trail has and will continue to provide new re creational opportunities along the Kissimmee River and around Lake Okeec hobee. Potential recr eational opportunities include fishing, hunting, camp ing, hiking, bicycling, canoei ng, and birding. Additional opportunities include connecting the tra il to surrounding commun ities and providing equestrian access in limited areas.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 6: Recreation

157 Figure 6-1. The Kissimmee River section of the Florida National Scenic Trail (WMA = Wildlife Management Area; FTA = Florida Trail Association; SOR = Save Our Rivers)158 Chapter 6: Recreation Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Figure 6-2. The Lake Okeechobee section of the Florida National Scenic Trail (WMA = Wildlife Management Area; FTA = Florida Trail Association; SOR = Save Our Rivers)Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 6: Recreation

159 Once they reach the Hoover Dike at Clewiston, hikers heading north from Big Cypress have the choice of walking around the east or west side s of Lake Okeechobee. Scenic views of the lake and the adjacent agri cultural lands are afforded from the trail at Clewiston, Lake Harbor, South Bay, Pahokee, and on Torrey Island west of Belle Glade.


### D3. Florida Cracker Trail

The Florida Cracker Trail is a historic east-west route th at Florida cattlemen followed each spring until the 1930s. The trail passes through Manatee, Hardee, Highlands, Okeechobee, and St. Lucie Count ies. Each year since 1988, the historical return trip of the cattle drive has been reenacted. The Florida Legislature named and recognized the Florida Cracke r Trail in 1986, and the trail is officially designated on FDOT maps. 

### D4. Fishing Tournaments The FWC estimates over 250,000 angler hours are dedicated to fishing tournaments on Lake Okeechobee annually. Th is accounts for 25 percen t of all statewide tournament activity. Based on their reservation numbers, Ok ee-Tantie Park in Okeechobee hosted 50 tournaments in 1994. Other popular tournament sites are Roland Martin's Marina, Anglers Inn, Harney Pond, the Indian Prairie Cana l, and the city ramps in Clewiston, Moore Haven, Lakeport, and Belle Glade. Combined, thes e sites probably host the same number of tournaments as Okee-Tantie. 

### D5. Boating Events
The Kissimmee Boat-A-Cade, formed in 1947, uses th e Kissimmee Waterway for three annual boating trips from the city of Kissimmee through Lake Okeechobee. From Lake Okeechobee, the boats proceed to eith er the east or west coast through the Okeechobee Waterway, dependi ng upon their destination. A total of about 300 boats participate annually in the Ki ssimmee Boat-A-Cade. Boat size s range from 18 to 40 feet. In the past, the Boat-A-Cade has also made trips to the Florida Keys and Charleston, South Carolina.160 Chapter 6: Recreation Lake Okeechobee SWIM Plan - June 21, 2002 DRAFTLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 7: Navigation

161 

## Chapter 7 NAVIGATION

Lake Okeechobee, the Okeechobee Wate rway, and the Kissimmee River have undergone a century of development for navi gation. Construction has been accomplished by both private individuals and public agenci es. The development phases of the federal navigation project is descri bed in more detail in the Lake Okeechobee and Okeechobee Waterway Master Plan (USACE, 1986) and Environmental Restorat ion of the Kissimmee River: Feasibility Report and Environmental Impact Statement (1991). The development of the Okeechobee Waterw ay began in the 18 00s with dredging that opened 360 contiguous mile s of navigable waterway c onnecting the Caloosahatchee River, Lake Okeechobee, and th e Kissimmee River. Dredging of the St. Lucie River began in the early 1900s, connecting the lake with the Atlantic Ocean. In 1930, the federal government adopted the Okeechobee Waterway as a federal naviga tion project with due consideration to be given to flood contro l (USACE, 1986). The navi gation channel has an authorized project depth of 8 feet ba sed upon a Lake Okeechobee stage of 12.56 feet NGVD. The Kissimmee River has an authori zed navigation project depth of 3 feet at ordinary stage of the river (USACE, 1991). In addition to the federal navigation projec t, about 31 miles of historic boat trails are located in the marsh zone of Lake Okeechobee. These tr ails are used primarily for recreational fishing. The USACE ma intains these historic boat tr ails to provide safe harbor for recreational boaters during inclement w eather. Numerous unplanned recreational boat trails have also been developed and ma intained by continual boat use. No one is responsible for maintaining these unplanned boat trails. The major challenge addresse d by this chapter is to in crease public access to the lake in order to enhance recreational us es including fishing, boating, and wildlife observation. This challenge will be addressed by the SFWMD by supporting the Lake Okeechobee Scenic Trail development and c ontinuing to work with ecotourism groups. 

## A. GOALS, OBJECTIVES, AND STRATEGIES Goal 1: Maintain navigability fo r commercial and recreational uses within Lake Okeechob ee and the Lake Okeechobee Waterway Objective 1: Provide assistance to ma intain navigation within the federallyoperated navigation project encomp assed by Lake Okeechobee and the Okeechobee Waterway Strategy 1: Consistent with water supply and environmental objectives, maintain water storag e in Lake Okeechobee to ensure162 Chapter 7: Navigation Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

reasonable access to marinas and commercial and recreational channels Strategy 2: Support the USACE’s ef forts to control aquatic weeds on the Okeechobee Waterway and on the recreati onal boat trail system to levels that do not unreasonably impede recreational access consistent with the approved Lake Okeechobee Aquatic Plant Management Plan Strategy 3: Maintain designated na vigation locks and structures for the federal navigation project Strategy 4: Support the USACE’s ef forts to maintain and enhance navigation within the Okeechobee Waterway 

### Goal 2: Maintain navigability for recreational uses within the Kissimmee River Objective 1: Provide assistance to ma intain recreationa l navigation within the Kissimmee River Strategy 1: Support the USACE’s ef forts to maintain recreational navigation within the Kissimmee River consistent with the Kissimmee River Restoration Project Strategy 2: Control aquatic weed s on the Kissimmee River to levels that do not unreasonably impede r ecreational access consistent with the approved Kissimmee River A quatic Plant Management Plan


## B. NAVIGATION LOCK STRUCTURES
Navigation lock structures on Lake Okeechobee, the Okeechobee Waterway, and the Kissimmee River are managed by the USACE or the SFWMD ( Table 7-1 ). The USACE maintains five navigation boat lock s on the Okeechobee Waterway. Boaters on the Okeechobee Waterway may take two distinct routes across Lake Okeechobee from the Port Mayaca Lock to the M oore Haven Lock. One is a 39- mile long open water crossing while the other, known as the Rim Canal, follows 50 miles along the southern shore. All locks, other than those located in the Okeechobee Waterway, have been turned over to the SFWMD for operation and maintenance. This leaves the Franklin, Ortona, Moore Haven, Port Mayaca, and St. Luci e locks under the jurisdiction and regular operation and maintenance of th e USACE. In the event of a hurricane, jurisdiction of all locks on Lake Okeechobee re verts to the USACE.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 7: Navigation

163 

## C. SUMMARY OF NAVIGATION ISSUES
C1. Lake Okeechobee and the Okeechobee Waterway Boating access to Lake Okeechobee is affected by water levels. At lake stages below 12.56 feet NGVD, the au thorized project depth cannot be maintained. During periods of low lake level, navigational access to much of the fishing area is reduced. Conservation measures may be imposed which restrict discharges from the lake including limitations by the USACE on th e frequency of lockage operation. The USACE is the lead agency in assuring and maintain ing navigability in the lake. In addition to the issues of adequate depth and unimpaired st ructural operations, travel impediment due to aquatic weed infestations is also an issue. This is of concern both within the Okeechobee Waterway and within th e numerous boat trails and within the Rim Canal where recreational uses might be adve rsely impacted. The Rim Canal and boat trails also become inaccessible dur ing low water periods. The US ACE administers an Aquatic Weed Control Program. Table 7-1. Navigation lock structures on the federal project a

Lock Managing Agency Water Body/ Waterway Width/ Length (feet) Hours of Operation St. Lucie Lock (S-80) USACE St. Lucie Canal 50/250 6AM-10PM Port Mayaca Lock (S-308B) USACE St. Lucie Canal/ Lake Okeechobee 56/400 6AM-10PM
Clewiston Lock (S-310) SFWMD Lake Okeechobee 50/60 5:30AM-8PM b Moore Haven Lock (S-77) USACE Caloosahatchee/ Lake Okeechobee 50/250 6AM-10PM
Fisheating Creek Lock (S-131) SF WMD Lake Okeechobee 15/50 5:30AM-8PM b Buckhead Ridge Lock (S-127) SFWMD Lake Okeechobee 15/50 5:30AM-8PM b Taylor Creek Lock (S-193) SFWMD Lake Okeechobee 50/60 5:30AM-8PM b Henry Creek Lock (G-36) SFWMD Lake Okeechobee 15/50 5:30AM-8PM b Chancey Bay Lock (S-135) SFWMD Lake Okeechobee 15/50 5:30AM-8PM b Ortona Lock (S-78) USACE Caloosahatchee 50/250 6AM-10PM W.P. Franklin Lock (S-79) U SACE Caloosahatchee 56/400 6AM-10PM S-61 SFWMD Kissimmee River 30/90 7AM-6PM c S-65 SFWMD Kissimmee River 30/90 7AM-6PM c. S-65A SFWMD Kissimmee River 30/90 8AM-5PM c. S-65C SFWMD Kissimmee River 30/90 8AM-5PM c. S-65D SFWMD Kissimmee River 30/90 8AM-5PM c. S-65E SFWMD Kissimmee River 30/90 7AM-6PM c. a. Source: USACE, 1986 and SFWMD Contract C-4209, August 17, 1993 b. Open until 9:00 PM from May 1 to September 30 c. Weekend hours for all Kissi mmee River locks: March 1-October 31, 5:30AM-7:30PM; November 1-February 28, 5:30AM-6:30PM164 Chapter 7: Navigation Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT
The Okeechobee Waterway has had an authorized federal navi gation depth of 8 feet since the 1930s. In the 1960s, the Caloosah atchee (C-43) and St. Lucie (C-44) Rivers were widened and deepened as part of th e C&SF Project to accommodate flood releases from Lake Okeechobee. The auth orized flood control channel depth of 26 feet is greater than the navigation channel depth the USACE is required to maintain. Therefore, the Okeechobee Waterway has not needed to be dr edged for navigation, except for in the St. Lucie Inlet area, where the Okeechobee Wate rway intersects with the Intracoastal Waterway. Navigational dredging of the St . Lucie River downstr eam of S-80 is the responsibility of the Florida Inland Navigation District. The St. Lucie Inlet area was last dredged in 1980, and the area is in need of dredging again.


### C2. Kissimmee River Since 1902, the Kissimmee River (C-38) has had an authorized navigation depth of 3 feet. The actual channel depth is greater th an the authorized channel depth the USACE is required to maintain, because the C&SF Projectchannelized the rive r into a 30-foot deep canal for flood protecti on. Presently, the size of the navigation locks, which provide a minimum depth of five feet, limit the size of boats in the C-38 Canal (USACE, 1991). In addition, the five bridges cros sing the Kissimmee River, withvertical clearances ranging from 12 to 20 feet, may restrict the height of boats.
Channelization of the Kissimmee River resulted in dest ruction of wetlands and other riverine habitats. As a result, in 1992, the USACE and SFWMD agreed to a plan that includes backfilling 22 miles of the channe l and removing the S- 65B and S-65C locks. The S-65B navigation lock wa s removed in 2000 during the fi rst phase of restoration. During Phase I of the restoration constructi on, navigation along the Kissimmee River has been restricted from north to south, although most of the original river remains open to recreational use both north of the construction project and south of the project ( Figure 7- 1 ). Further restrictions to north-south navigation along the ri ver will happen as navigation locks are taken out of servi ce for major overhauls. After the Kissimmee River Restoration Project is completed, the restor ed river will meet the author ized navigation depth of 3 feet during normal flow conditions.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 7: Navigation

165 Figure 7-1. Navigation of the Kissimmee River during Phase I construction of the Kissimmee River Restoration Project166 Chapter 7: Navigation Lake Okeechobee SWIM Plan - June 21, 2002 DRAFTLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 8: Public Involvement and Intergovernmental

167 

## Chapter 8 PUBLIC INVOLVEMENT AND INTERGOVERNMENTAL COORDINATION

The condition of the lake and the stat us of District management efforts traditionally have been rout inely reported to th e public as part of the agency’s ongoing public communication effort. The Surface Water Improvement and Management (SWIM) Plan - Update for Lake Okeechobee (SFWMD, 1997a) establis hed a specific public information goal to provide c itizens with information con cerning Lake Okeechobee water resource management issues and to imple ment an effective public awareness and participation project. In addition, the SWIM Act requires the Di strict to coordina te with other public agencies as part of the process of prep aring, reviewing, and a pproving Lake Okeechobee SWIM plan updates (Sections 373.453 and 373.455, F.S.). The development of a Public Participation Program and an Intergovernmental Coordinati on Program will promote the involvement of the public and other ag encies in the SWIM planning process. This chapter presents goals , objectives, and strategies that have been used to develop the public information and participation program to in form the residents of South Florida about Lake Okeechobee water resource issues, and provide opportunities for the public to participate in the Lake Okeechobee SWIM planning process. The addition of a dedicated, organized approach for keeping local government staff members and elected officials up to date on Lake Okeechobee SWIM issues has led to more active local government involvement and enhanced public communication. The methods for developing and disseminating informat ion that describes the characteristics of the lake ecosystem, conve ys a sense of the lake’s environmental sensitivity, and demonstrates Lake Ok eechobee’s prominence in the Kissimmee-Lake Okeechobee-Everglades ecosystem are as follows: • Foster a greater understanding of La ke Okeechobee’s role in meeting the water supply and flood protec tion needs of South Florida • Develop an understanding of human demands and impacts on Lake Okeechobee • Enlist public support for Lake Oke echobee restoration and preservation efforts • Promote an understanding of and consistency with Lake Okeechobee SWIM goals in other related efforts such as the CERP The Public Participation and Intergovernmental Coordination programs are designed to do the following:168 Chapter 8: Public Involvement and Intergovernmenta l Coordination Lake Okeechobee SWIM Plan - June 21, 2002
• Advise the public; county, state, and federal government agency staff; and elected officials of the nature and scope of Lake Okeechobee SWIM planning efforts • Keep open the lines of communication between the public and agency planners, listen to th e needs and the views of the public, and identify and respond to interested individuals, special interest groups, elected officials and agencies • Make available for agency and publ ic review and comment all plans, reports, data analyses, interpre tations, and other information • Facilitate interagency coordi nation in the development and implementation of action plans to achieve common water resource goals and objectives • Allow for facilitated public input into the planning process for future Lake Okeechobee restorati on and preservation efforts The major challenge addressed by this chap ter is to foster a greater understanding of Lake Okeechobee rest oration and preservation effort s and enlist public support for meeting established goals. Th is challenge will be addre ssed by enhancing public, local government, and interagency c oordination including discussi ons on problem solving and minimizing economic impacts; and by assisting local governme nts with the incorporation of SWIM considerations into local comprehensive plans. 

## A. GOALS, OBJECTIVES, AND STRATEGIES Goal 1: Prepare and implement an effective public awareness program Objective 1: Develop and distribute material s that inform the general public about the features of the La ke Okeechobee ecosystem, including its physical, chemical, and hydr ologic features; water quality and sediment characteristics; tributary basins; biological resource s; recreational resources; and the role of Lake Okeechobee in the Kissimmee-Lake Okeechobee-Everglades ecosystem Strategy 1: Within existing SFWMD pub lic information projects, generate and distribute information to explain the lake's capacity to address the flood protection, wate r supply, and environmental resource needs of South Florida an d, more specifically, within the Lake Okeechobee SWIM planning area Strategy 2: Prepare a public communications plan that will reflect major milestones in Lake Ok eechobee research and the SWIM planning process that will 1) focus on the actual issues andLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 8: Public Involvement and Intergovernmental

169 information that will be conveyed to various target audiences and 2) specify the appropriate communication vehicle(s) 

### Goal 2: Encourage public particip ation in the Lake Okeechobee SWIM planning process Objective 1: Create new opportunities for resi dents, scientists, business and commercial concerns, environmen tal groups, the regulated community, recreational users, and other special in terest groups to participate in the development of lake management strategies emphasizing participation by local populations and affected part ies within the Lake Okeechobee SWIM planning area Strategy 1: Develop a public participation and intergovernmental coordination process to suppor t Lake Okeechobee SWIM plan development and implem entation of lake restoration, preservation, and management strategies Strategy 2: Establish a Florida yards and neighbors project, in which volunteers are solicited fr om the community to implement water conservation, environmen tal enhancements, and reduced nutrient inputs from their own yards 

### Goal 3: Prepare and implement an effective intergovernmental awareness and involvement program Objective 1: Develop an intergovernme ntal participation and coordination process to focus on intergovernment al involvement through scheduling and pursuing anactive outreach program to involve all local, state, and federal entities with in terest in issues related to Lake Okeechobee. Strategy 1: Prepare an intergovernmental involvement plan, that reflects major milestones in Lake Okeechobee research, supports Lake Okeechobee SWIM Plan development, and the implementation of lake management strategies Strategy 2: Schedule and pursue an act ive outreach program to involve all local, state, and federal entities with interest in issues related to Lake Okeechobee Objective 2: Develop and coordinate workshops and meetings that inform appropriate government staff members and electe d officials about the features of the Lake Okeechobee ecosystem, it s physical, chemical, and hydrologic features; water quality and se diment characteri stics; tributary170 Chapter 8: Public Involvement and Intergovernmenta l Coordination Lake Okeechobee SWIM Plan - June 21, 2002
basins; biological resources; recreati onal resources; and the role of Lake Okeechobee in the Kissimmee-Lake Okeechobee-Everglades ecosystem Strategy 1: Develop and coordinate wo rkshops and meetings that inform appropriate government staf f members and elected officials regarding current and proposed restoration projects on Lake Okeechobee Strategy 2: Maintain communication withlocal government staff members and elected officials a bout current and proposed policy regarding the Lake Okeechobee ecosystem by involving agency staff members in regular local meetings and workshops Objective 3: Create methods for appropria te local government staff members and elected officials to be tter participate in the interagency process that results in public policy regarding the operation and management of Lake Okeechobee, and to link Lake Okeechobee SWIM projects with other interagency efforts Strategy 1: Use the Okeechobee Service Center as a clearinghouse for all lower Kiss immee Basin/Lake Okeechobee projects so staff members can bett er coordinate all system-related projects Strategy 2: Use the Okeechobee Service Center as a resource/ facilitator so that interagency and multigovernmental projects can be housed and/or coordinated locally


## B. REVIEW OF CURRENT PROJECTS
B1. Lake Okeecho bee-Closer Look The SFWMD publishes a document titled Lake Okeechobee-Closer Look . It was originally designed to accompany an informational natural history seminar on the lake, From Algae to Alligators: Th e Nature of Lake Okeechobee, that was presented in 1995. The document explores Lake Ok eechobee, discussing its past, present, and future in the context of man’s impacts on th e lake. An 8-page edition of this document was published in March 1995 and July 1997 (SFWMD, 1995, 1997b), and updated in November 2000 (SFWMD, 2000g). Most recently, it has been i ssued as a companion publication with this update.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Chapter 8: Public Involvement and Intergovernmental

171 

### B2. Media Coordination The District has established a weeklynewspaper column, Water Works, that frequently includes information specific to Lake Okeechobee restoration. It also keeps readers informed about upc oming meetings and invi tes public participation.
Media tours of Lake Okeech obee have been implemen ted. The purpose of these tours was to highlight the volunt eer tree planting efforts of District staff and to showcase successes with Lake Okeec hobee recession initiatives. 

### B3. Proposed Media Coordination Project The District proposes to de sign and implement a water media leadership project for state, local, and national editors a nd reporters, who frequently report on the environmental and water manageme nt issues of South Florida. Similar to other leadership projects, participants in this leadership cour se will have an opportunity for field trips and in-depth exposure to the competing demands on water resources in S outh Florida, as well as an opportunity to learn about process and decision making from anagency perspective. 

### B4. Proposed Public and Intergovernmental Coordination Communications Plan The District has begun deve loping a public and intergovernmental coordination communications plan. The communications plan will include, but may not be limited to, a series of articles su mmarizing SFWMD research effort s and publications pertaining to Lake Okeechobee undertaken si nce 1989. The project will e xplain how SFWMD research projects define and measure the extent of resource problem s and contribute toward the development of management strategies. The project will develop a reporting mechanism that tracks the progress of the regulatory programs in reduc ing the phosphorus loading to the lake, as well as the status of impl ementation of Lake Okeechobee Protection Act (Section 373.4595 F.S.) measures , which include the impleme ntation of the Dairy Rule and the Works of the District Rule, and development and implementation of TMDLs and BMPs. Special emphasis will be given to reporting to the public the status of Lake Okeechobee Protection Plan re storation efforts. Programupdates will communicate the effectiveness of efforts to date, including di scussions of current pr ogress, definitions of problems, results achieved to da te, and an indication of whet her objectives have been met. If management projects will not be proceeding as planned, effo rts will be made to explain why they are being discontinued, deferred, or redirected. Progr am updates will also describe SFWMD efforts to c oordinate SWIM planning activities with other agencies that share similar resource goals and objective and provide in formation concerning funding sources and project budgets.172 Chapter 8: Public Involvement and Intergovernmenta l Coordination Lake Okeechobee SWIM Plan - June 21, 2002
As much as possible, public communication efforts will be coor dinated with other Lake Okeechobee restoration ef forts. Meetings with the publ ic will include presentations on multiple projects and initiatives when possible. 

### B5. Proposed Intergovernmental an d Public Participation Project An intergovernmental and public particip ation project will generate methods to advise the public and elected officials of the nature and scope of the Lake Okeechobee SWIM planning efforts, maintain open line s of communication be tween the public and agency planners, listen to the needs and the views of the public, and identify and respond to interested individuals, special intere st groups, and other ag encies. Facilitated discussions on SWIM plan deve lopment will be held utilizi ng representatives from a wide variety of interests. Results of the facilitated discussions will be considered during development of future SWIM plan updates. The participation project wi ll identify key research ef forts for public review and assessment and prepare to report the results of those research efforts as early as possible. Issue papers may be prepared to inform target audiences and to frame discussions with agency planners. Methods of soliciting techni cal review and comment will be created and implemented. The project will be prepared to communicate the revise d status of research efforts and subsequent impact s on the SWIM planning process. The project will create avenue s for the public to review the status and address the effectiveness of SWIM res ource management efforts. Communities, special interest groups, and others affected by resource management projects will be identified and the role of external parties in th e development of management go als, objectives, and strategies will be defined. The project wi ll provide for the developmen t of a process to communicate with and solicit input from these target ed groups on the impact of lake management strategies. Subsequent revisi ons to management goals and objectives will be documented. The project will provide oppor tunities for other public ag encies to participate in the development and implementa tion of management projects. Potential activities include, but are not limited to, participation in issue- specific task forces or advisory groups; local meetings or workshops; cospons orship of studies to evalua te management alternatives; contribution of funding or in-k ind services for demonstrati on projects; and cost sharing the implementation of management projects.Lake Okeechobee SWIM Plan

– April 4, 2002 DRAFT Chapter 9: Budget

173 

### Chapter 9 

## BUDGET
The following table identifies the 1998

- 2000, 2001 and 2002 budgets for Lake Okeechobee projects. The project budgets are sorted by goals and objectives from Chapters 2, 3, and 4. Efforts were made to include all SFWMD contributions (con tract funds and staff time), as well as the funds appropriated to the SFWMD from the state. Federal contributions, such as the 50:50 Army Corps of Engineers cost

- share match for the Critical Projects have not been included.
The sources of this informati on include current District reports and internal budget line item amounts associated with Lake Okeechobee research, planning, and monitoring projects. Certain goals, objectives and several strategies do not have separate, identifiable projects associated w ith them at this time and therefore are not listed in the budget matrix.

### Table 9-1. Ongoing and new Lake Okeechobee SWIM related projects and funding levels (funds are ad valorem unless otherwise noted).

SWIM PL AN GOALS, OBJECTIVES AND PROJECTS FUNDING PERIOD 1998-2000 2001 2002 WATERSHED AND TRIBUTARY WATER QUALITY $ $ $ GOAL: Reduce pollutant loads from the watershed to protect aquatic life and

water quality in Lake Okeechobee TOTAL 15,656,130 3,753,336
Objective 1: Bring the overtarget basins down to their phosphorus loading targets SUBTOTAL 805,973 1,775,398

(Strategies 1-3) Works of the District monitoring - TP

Lab Analysis/testing 18,906 Backpumping 23,000 Works of the District applications

Dairy water quality monitoring 153,195 Watershed water quality monitoring 69,688 Inflow water quality monitoring 101,191 Water quality data anlysis/reporting 381,254 Buck Island beef cattle ranch study analysis 102,000 Beef Cattle Management Practice Research

Buck Island Ranch, beef cattle BMP study 150,000 158,516 Watershed projects

Lake and watershed GIS development 190,000 209,867 Model uncertaintly 15,900 Watershed Modeling Graphical User Interface (GUI) 51,000 Watershed P budget 48,273 169,812 Lakewide P budget 119,800 76,211 TMDL support 25,000 Watershed P dynamics/ model development 57,724 56,014 Model applications & watershed P budget analysis 199,276 173,625 Modeling applications related to permit applications and CERP 31,119

* State-appropriated funding * * EPA/DEP partial fundingSWIM PLAN GOALS, OBJECTIVES AND PROJECTS FUNDING PERIOD 1998-2000 2001 2002 $ $ $ Objective 2: Implement the components of the Lake Okeechobee Protection Program

and Permits to meet the TMDL target by 2015 (Strategies 1-8) SUBTOTAL 14,444,157 1,659,200 Dairy Best Available Technologies 1,644,500 427,750

* Isolated wetland restoration program 4,500,000

* LO cow-calf BMPs 225,000

* LO wetland research 350,000 LO Regulation Schedule 21,392 * * Tributary sediment removal study 319,985 67,199 Natural Resources Economics Study 70,000 80,000

* P Source Control Grant Program 7,500,000 Mandated reports 58,140 52,626

* LO program planning and reporting 15,000 242,732 SWIM Plan 58,140 13,893 * * Residuals study 257,000 200,000 Objective 3: Achieve State Class 1 Water Quality Standards (Chapter 60-302, F.A.C.)

within Lake Okeechobee and Class III Water Quality Standards within the Lake's tributaries (Strategies 1-9) SUBTOTAL 917,000 203,000 159,369 Nutrient budget calculations and water quality analysis 917,000 203,000 159,369

* State-appropriated funding * * EPA/DEP partial fundingSWIM PLAN GOALS, OBJECTIVES AND PROJECTS FUNDING PERIOD 1998-2000 2001 2002 IN L AKE WATER QUALITY $ $ $ GOAL: Reduce in-lake nutrients to attain a more natural (lower) frequency of

potentially harmful algal blooms TOTAL 1,200,000 896,000 3,973,608 Objective 1: Determine the economic, engineering, and ecological feasibility of

reducing internal phosphorus loading from lake sediments Strategies 1-2 SUBTOTAL 1,092,060 Lake pilot dredging project 648,300 * * Lake sediment management study 403,760

* Confined disposal facility management 40,000 Objective 2: Quantify rates of internal nutrient loading from lake sediments so that

accurate predictions can be made about the timing and extent of lake responses to potential management actions such as sediment removal (Strategies 1-2) SUBTOTAL 487,000 1,013,387 Sediment P release 16,000 16,000 Sediment P dynamics 71,000 186,698 Sediment P dynamics study 179,600 Lake water quality and hydrodynamic modeling 179,000 95,917 Spatial scale hydrodynamic & water quality model 58,000 269,290 Hydrodynamic and water quality data during hurricane season 185,965 Model update and maintenance 179,000 95,917 Objective 3: Reduce uncertainty about in-lake sources, sinks, and cycling of nitrogen

and phosphorus using research and modeling approaches (Strategies 1-2) SUBTOTAL 1,200,000 274,000 1,474,000 In-lake research: nutrient impacts 1,200,000 274,000 1,474,000 Objective 4. Quantify trends in limnetic and marsh zone water quality and progress

towards established lake enhancement goals (Strategy 1) SUBTOTAL 0 261,364 Lake Water Quality Monitoring 224,576 Long-term water quality trends evaluation 36,788 Objective 5: Determine the impact of submerged aquatic vegetation on lake water

quality (Strategies 1-2) SUBTOTAL 135,000 132,797 Submerged plant assessment 73,000 72,435 Littoral vegetation assessment 62,000 60,362

* State-appropriated funding * * EPA/DEP partial fundingSWIM PLAN GOALS, OBJECTIVES AND PROJECTS FUNDING PERIOD 1998-2000 2001 2002 ENVIRONMENTAL RESOURCES $ $ $ GOAL: Protect and enhance the environmental resources of Lake Okeechobee, in

terms of biological diversity, ecological functions, and the distribution and abundance of native plants and animals TOTAL 615,354 1,312,996 Objective 1: Quantify how variations in lake water level affect the environmental

resources, and use this information to set appropriate lake management goals (Strategies 1-5) SUBTOTAL 86,000 102,435 Water level impacts Torpedo grass vs. depth 67,000 30,000 Plankton algal bloom assess. 19,000 72,435 Objective 2: Develop a predictive understanding of nutrient dynamics in the lake

ecosystem, and use this information in support of the CERP and TMDL process (Strategies 1-3) SUBTOTAL 0 419,000 Predictive modeling 419,000 Objective 3: Identify exotic species that threaten native plants and animals in the lake

and develop and implement programs for their control (Strategies 1-3) SUBTOTAL 214,354 408,965 In lake research/exotic plants 137,000 218,160 Torpedo grass eradication 140,805 Exotic plant assessment 77,354 20,000 LO torpedograss seed bank 30,000 Objective 4: Quantify long-term trends in the lake’s ecological values (Strategies 1-2) SUBTOTAL 315,000 382,596

Submerged veg research/mapping 161,000 208,689 In lake ecological trend assessment 154,000 173,907
PERIOD TOTAL FOR ALL GOALS AND OBJECTIVES 2,117,000 16,964,484 8,880,571 GRAND TOTAL FOR ALL GOALS AND OBJECTIVES 27,962,055

* State-appropriated funding * * EPA/DEP partial fundingLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Glossary

195 

## GLOSSARY

Acre-Foot The volume of water that would cover one acre to a depth of one foot; 43,560 cubic feet; 1,233.5 cubic meters; 325,872 gallons. Algal Bloom Rapid growth of algae on the surface of lakes, st reams, or ponds; stimulated by nutrient enrichment. Aquifer A portion of a geologic formation or form ations that yield water in sufficient quantities to be a supply source. Backpumping The practice of pumping water that is leaving the area back into a surface water reservoir. Basin (Surface Water) A tract of land drained by a surf ace water body or its tributaries. Best Management Practices (BMPs) Agricultural management activities designed to achieve an important goal, such as reduc ing farm runoff, or optimizing water use.

Biomass The amount of living matter, as ina unit area or volume of habitat.

Bioturbation The recycling of nutrients from la ke sediments to the overlying water column caused by the burrowing a nd feeding activities of benthic invertebrates and fish. Central and Southern Florida Project Comprehensive Review Study (Restudy) A five-year study effort that l ooked at modifying the current C&SF Project to restore the Kissimmee-Lake Okeechobee-Ev erglades and South Florid a ecosystem while providing for the other water relate d needs of the region. The study concluded with the Comprehensive Plan being presented to Congress on July 1, 1999. The recommendations made within the Restudy, that is, structural and operationa l modifications to the C&SF Project, are being further re fined and will be implemented in the Comprehensive Everglades Restoration Plan (CERP).

Central and Southern Fl orida (C&SF) Project A complete system of canals, storage areas, and water control structures spanning the area from Lake Okeechobee to both the east and west coasts , and from Orlando south to the Everglades. It was designed and constructed during the 1950s by the United States Army Corp s of Engineers (USACE) to provide flood control and impr ove navigation and recreation. Chapter 298 Special Drainage Districts East Beach Water Contro l District, East Shore Drainage District, S outh Shore Drainage District, the Industrial Canal, South Florida Conservancy [S-236], and 715 Farms.

Chironomids Any of a family (Chironomidae) of midges that lack piercing mouthparts.196 Glossary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Chlorophytes Class I through V Surface Water Quality Standards As defined by Chapter 62- 302.400, F.A.C., all surface waters in Florida ha ve been classified ac cording to designated use as follows: • Class IPotable water supplies • Class IIShellfish propagation or harvesting • Class IIIRecreation, propagation, and maintenance of a healthy, wellbalanced population of fish and wildlife • Class IVAgricultural water supplies • Class VNavigation, utilit y, and industrial use Comprehensive Everglades Restoration Plan (CERP) The implementation of recommendations made within the Restudy , that is structural and operational modifications to the C&SF Proj ect are being further refine d and will be implemented through this plan. Consumptive Use Use that reduces an amount of wa ter in the source from which it is withdrawn. Consumptive Use Permit A permit issued by the SFWMD allowing utilities to withdraw ground water for consumptive use.

Control Structure A man-made structure designed to re gulate the level/flow of water in a canal (e.g., weirs, dams). Cynobacteria Blue-green algae.

Denitrification Reduction of nitrates or nitrites commonly by bacteria (as in soil) that usually results in the escape of nitrogen into the air.

Diatom Any of a class (Bacillariophyceae) of minute planktonic unicellular or colonial algae with silicified skeletons. Epiphyton Plants that derive their moisture and nut rients from the air and rain and usually grow on other plants Estuary A water passage where the ocean or sea meets a river. Eutrophication The gradual increase in nutrients in a body of water. Natural eutrophication is a gradual process, but human activities may gr eatly accelerate the process.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT Glossary

197 Everglades Agricultural Area (EAA) The area of histosols (muck) predominantly to the southeast of Lake Okeechobee that is used for agricultural production. Everglades Construction Project The foundation for the larg est ecosystem restoration program in the history of Flor ida. It is composed of 12 in terrelated construction projects located between Lake Okee chobee and the Everglades, including over 47,000 acres of stormwater treatment areas (STAs). Everglades Protection Area This area is comprised of the Water Conservation Areas and Everglades National Park. Everglades Stormwater Program A program to ensure that water quality standards are met at all structures not included in the Everglades Construction Project. Exotic Invasive Plant Species A nonnative species that te nds to outcompete native species and become quickly esta blished, especially in areas of disturbance or where the normal hydroperiod has been altered.

Food Web The totality of interacting food ch ains in an ecological community.

Fiscal Year The South Florida Water Management District’s fiscal year begins on October 1 and ends on September 30 the following year. Geographic Informations Systems (GIS) Mapping The abstract representation of natural (or cultural) features of a landscape into a digital da tabase, geographic information system. Governing Board Governing Board of the South Flor ida Water Management District.

Ground Water Water beneath the surface of the ground, whether or not flowing through known and definite channels.

Hectare A unit of measure in the metric sy stem equal to 10,000 square meters (2.47 acres). Hydroperiod The frequency and duration of inundati on or saturation of an ecosystem. In the context of characterizing wetlands, the te rm hydroperiod describes that length of time during the year that the substrate is ei ther saturated or covered with water. Institute of Food and Agri cultural Sciences (IFAS) The agricultural branch of the University of Florida that performs research, educat ion, and extension. Indian River Lagoon Extending for 156 miles from north of Cape Canaveral to Stuart along the east coast of Florida, this lagoon is America’s mo st diverse estuary, home to more than 4,000 plant and animal species.198 Glossary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Lagoon A body of water separated from the ocean by barrier islands, with limited exchange with the ocean through inlets.

Lake Okeechobee This lake measures 730 square miles and is the second largest freshwater lake wholly within the United States. Lake Okeechobee SWIM Planning Area The major basins that are direct tributaries to Lake Okeechobee, including those basins th at are hydrologically upstream and/or from which water is presently released or pumped into the lake on a regular basis.

Levee An embankment to prevent flooding, or a co ntinuous dike or ridge for confining the irrigation areas of land to be flooded.

Littoral Of, relating to, situated, or growing on or near a shore.

Load Concentration times flow.

Marsh A frequently or continually inunda ted wetland charact erized by emergent herbaceous vegetation adapted to saturated soil conditions.

Mesocosm An experimental appro ach to quantify the respons es of a whole plant and animal community. Metaphyton microgram One millionth of a gram

Minimum Flows a nd Levels (MFL) The point at which furt her withdrawals would cause significant harm to water resources. National Geodetic Vertical Datum (NGVD) A nationally established references for elevation data. Native Nuisance Species Native plant species that spread rapidly under disturbed conditions and displace more desirable plant communities.

Nitrification The oxidation (as by bacteria) of a mmonium salts to nitrites and the further oxidation of nitrites to nitrates. Nitrogen Fixation The metabolic assimilation of atmospheric nitrogen into ammonia by soil microorganisms and especially rhizobia. Nonpoint source Source originating over broad areas, such as areas of fertilizer and pesticide application or leaking sewer syst ems, rather than from discrete points. Nutrient Cycle The cyclic conversions of nutrients from one form to another within the biological communities. A simple example of such a cycle would be the production andLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Glossary

199 release of molecular oxygen (O 2 ) from water (H 2 O) during photosynthesi s by plants and the subsequent reduction of atmospheric oxygen to water by the respiratory metabolism of other biota. The cycle of nitrogen is mu ch more complex, wi th the nitrogen atom undergoing several changes in oxidation state (N 2 , NO 3 -, R-NH 2 , and NH 4 , among others) during the cycling of this element through the biological community , and into the air, water, or soil, and back. Oligochaetes Any of a class or orde r (Oligochaeta) of herm aphroditic terrestrial or aquatic annelids (as an earthworm ) that lack a specialized head Pelagic Zone Open water zone.

Performance Measure Performance measures quantif y how well or how poorly an alternative meets a sp ecific objective. Good pe rformance measures ar e quantifiable, have a specific target, indicate when a target has been reached, and measur e the degree to which the goal has been met. Periphyton Organisms (as some algae) that li ve attached to underwater surfaces Phytoplankton The floating, usually minute, plant life of a body of water.

Point Source Any discernible, confined and disc rete conveyance from which pollutants are or may be discharged, in cluding, but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissur e, container, rolling stock, concentrated animal feeding operation, or vessel or other floating craft. This term does not include agricultural stormwater discharges and returnflows from irrigated agriculture.

Pollution Load Reduc tion Goals (PLRGs) Targeted reductions in pollutant loadings to a water body needed to achieve watershed management goals. Public Water Supply Demand All potable water supplie d by regional water treatment facilities with pumpage of 0.5 million gallons per day (mgd) or more to all customers, not just residential.

Reasonable-Beneficial Use Use of water in such quantity as is necessary for economic and efficient utilization fo r a purpose and in a manner th at is both reasonable and consistent with the public interest. Regional Water Supply Plan Detailed water supply plan developed by the District under Section 373.0361, F.S.

Reservoir A man-made or natural lake where water is stored. Rolling Average The arithmetic average of a sequen ce of data within a data set moved and calculated sequentially to smooth the data and reveal trends (e.g., fi ve-year rolling total phosphorus concentrations).200 Glossary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Saline Water Water with a chloride concentration greater than 250 milligrams per liter. The term saline water include s brackish water and seawater.

Saltwater Water Intrusion This occurs when more dens e saline water moves laterally inland from the seacoast, or moves vertical ly upward, to replace fresher water in an aquifer.

Seawater Water which has a chloride concentr ation equal to or greater than 19,000 milligrams per liter.

Sedimentation The action or process of fo rming or depositing sediment. Significant Harm (Term will be defined during pr oposed rule development process) An adverse impact to water resources or the e nvironment, relating to an established minimum flow or level for a water bod y; generally temporary but not necessarily short-lived, especially when the period of recovery from the adverse im pact exceeds several months to several years in duration; more intense thanharm, but less intense than serious harm. Slough A channel in which wate r moves sluggishly, or a pl ace of deep muck, mud, or mire. Sloughs are wetland habi tats that serve as channe ls for water draining off surrounding uplands and/or wetlands. Stage The elevation of the surface of a surface water body.

Stormwater Surface water resulting fro m rainfall that does not percolate into the ground or evaporate. Stormwater Treatment Area (STA) A system of large treatment wetlands that use naturally occurring biological processes to reduce the levels of phosphorus from agricultural runoff prior to it being released to the Everglades. Supply-Side Management The conservation of water in Lake Okeechobee to ensure that water demands are met while reducing the risk of serious or significant harm to natural systems.
Surface Water Water that flows, falls, or colle cts above the surface of the earth. Surficial Aquifer System The major source of water in the LEC planning area. It is unconfined, consisting of vary ing amounts of limestone and sediments that extend from the land surface to the top of an intermediate confining unit. Total Maximum Daily Load (TMDL) The level of loading to a body of water that will protect uses and maintain compliance with wa ter quality standards (defined in the Clean Water Act [Title 33, Chapter 26, S ubchapter III, Section 1313(d)]). Trophic Level One of the hierarchical strata of a food web characterized by organisms which are the same number of steps removed from the primary producersLake Okeechobee SWIM Plan - June 21, 2002 DRAFT Glossary

201 Turbidity The measure of suspended material in a liquid. Vertical Migration The vertical movement of oil, gas, contamin ants, water, or other liquids through porous and permeable rock.

Wastewater The combination of liquid and water borne discharges from residences, commercial buildings, industrial plants and institutions together with any ground water, surface runoff, or leachate that may be present.

Water Conservation Reducing the demand for water th rough activities that alter water use practices, e.g., improving effi ciency in water use, redu cing losses of water, and reducing waste of water. Water Conservation Areas (WCAs) That part of the original Everglades ecosystem that is now diked and hydrologicall y controlled for flood cont rol and water supply purposes. These are located in the western portions of Miami-Dade, Broward, and Palm Beach Counties, and preserve a tota l of 1,337 square miles, or a bout 50 percent of the original Everglades. Water Budget An accounting of total water use or projected water use for a given location or activity.

Watershed The drainage area from wh ich all surface water drains to a common receiving water body system. Watershed Management Goals Goals that encompass any one or all of the major water management district responsibilities: flood protection, water supply , water quality, and environmental system protec tion and enhancement. The goals provide the general direction for developing cohesive strategies to manage wate r resources within a drainage basin, subbasin, or segment of a drainage basin or subbasin. Water Shortage Declaration Water shortage declarations can be made by the District’s Governing Board pursuant to Rule 40E-21.231, F.A.C., which states “If ...there is a possibility that insufficient water will be available within a source class to meet the estimated present and anticipate d user demands from that sour ce, or to protect the water resource from serious harm, the Governing Bo ard may declare a water shortage for the affected source class.” A gradual progression in severity of restri ction is implemented through increasing phases. Once d eclared, the District is requi red to notify permitted users by mail of the restrictions and to publ ish restrictions inarea newspapers.
Wetlands Areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to suppor t a prevalence of vegetation typically adapte d for life in saturated soil conditions. Xeriscape TM Landscaping that involve s seven principles: prope r planning and design; soil analysis and improvement; practical turf areas; appropriate plant selection; efficient irrigation; mulching; and appropriate maintenance.202 Glossary Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT

Zooplankton The passively floating or weakly sw imming, usually minute, animal life of a body of water.Lake Okeechobee SWIM Plan - June 21, 2002 DRAFT References

183 

## REFERENCES

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