Manatee River CWM (PDF) - Southwest Florida Water Management ...

MANATEE RIVER 

COMPREHENSIVE 

WATERSHED 

MANAGEMENT PLAN 

April 26, 2001 

Prepared by: 

The Southwest Florida Water Management District 

in Cooperation with 

Manatee County, City of Bradenton, and City of Palmetto

The District does not discriminate upon the basis of any individual’s disability 

status. Anyone requiring reasonable accommodation under the ADA should contact 

Gwen Brown, Resource Management Department at 352-796-7211 or 1-800-423-1476 

(Florida only), extension 4226; TDD ONLY 1-800-231-6103 (Florida only); FAX 352- 

754-6885/SUNCOM 663-6885.

MANATEE RIVER 

COMPREHENSIVE 

WATERSHED 

MANAGEMENT PLAN 

April 26, 2001 

Prepared by: 

Southwest Florida Water Management District

Table of Contents 

CWM Team Members ............................................... C-1 

Executive Summary ................................................ E-1 

1.0 INTRODUCTION ...............................................1-1 

1.1 Comprehensive Watershed Management ........................1-1 

1.2 Coordination With Local Governments and Other Agencies ..........1-2 

1.3 Funding Commitments .......................................1-2 

1.4 Implementation .............................................1-3 

1.5 Future of CWM - A Watershed-based Partnership Approach .........1-3 

2.0 MANATEE RIVER WATERSHED DESCRIPTION ....................2-1 

2.1 Location ................................................2-1 

2.2 Climate .................................................2-1 

2.3 Physiography ............................................2-2 

2.4 Hydrogeology ............................................2-3 

2.5 Population and Economy ...................................2-4 

2.6 Land Use, Growth and Development ..........................2-6 

2.7 Transportation...........................................2-12 

2.8 References .............................................2-13 

3.0 WATER QUALITY ............................................. 3-1 

3.1 Water Quality Goals and Management in the Manatee River Watershed 

...................................................... 3-1 

3.1.1 Section Overview ................................... 3-1 

3.1.2 Water Quality Goals and Standards ..................... 3-1 

3.1.3 Water Quality Management and Sources of Water Quality Data for 

the Manatee River Watershed ......................... 3-4 

3.2 Introduction to Water Quality Issues of the Manatee River Watershed 

...................................................... 3-9 

3.2.1 Section Overview ................................... 3-9 

3.2.2 Water Quality Problems .............................. 3-9 

3.3 Review of Surface Water Quality Information and Issues ......... 3-11 

3.3.1 Section Overview .................................. 3-11 

3.3.2 The Upper Manatee River ........................... 3-12 

3.3.3 The Middle Manatee River ........................... 3-15 

3.3.4 The Lower Manatee River ........................... 3-17 

3.3.5 The Upper Braden River ............................ 3-19 

3.3.6 The Middle Braden River ............................ 3-20 

3.3.7 The Lower Braden River ............................ 3-22 

Manatee River Comprehensive Watershed Management Plan 

April 26, 2001 

-i-

Table of Contents Continued - 

3.3.8 Lakes and Isolated and Semi-Isolated Freshwater Wetlands 

................................................ 3-23 

3.3.9 Point Source Pollution .............................. 3-23 

3.3.10 Constituent Loading Studies ......................... 3-24 

3.4 Review of Ground Water Quality Information and Issues ......... 3-26 


3.4.2 The Surficial Aquifer ................................ 3-26 

3.4.3 The Intermediate Aquifer ............................ 3-27 

3.4.4 The Floridan Aquifer (Upper Floridan Aquifer) ............ 3-27 

3.4.5 Aquifer Storage and Recovery ........................ 3-28 

3.4.6 Areas Susceptible to Ground Water Contamination ....... 3-28 

3.5 Water Quality Issues/Problems, Strategies and Action Plans ..... 3-29 


3.5.2 Nutrient Pollution ................................. 3-29 

3.5.3 Toxicant Pollution ................................. 3-32 

3.5.4 Pathogens and Public Health Impacts .................. 3-36 

3.5.5 Flow-Related Water Quality Problems .................. 3-37 

3.5.6 Data Gaps and Monitoring Needs ..................... 3-39 

3.6 References ............................................ 3-40 

4.0 FLOOD PROTECTION ..........................................4-1 

4.1 Introduction ..............................................4-1 

4.2 General Description of Watershed and Community ...............4-3 

4.3 Historic Floods of Record ...................................4-4 

4.4 Flood Hazard Information ..................................4-6 

4.5 Summary of Stormwater Management Studies ...................4-6 

4.5.1 Stormwater Management Studies .......................4-6 

4.5.2 USGS Gages - Flow Data ............................4-12 

4.6 Regulator/Authority and Special Rules ........................4-12 

4.6.1 SWFWMD Regulations ..............................4-13 

4.6.2 County Regulations .................................4-13 

4.6.3 Municipal Regulations ...............................4-14 

4.6.4 U. S. Army Corps of Engineers (USACE) Regulations .......4-14 

4.6.5 Florida Department of Environmental Protection Regulations .4-14 

4.7 Land Acquisition Program ..................................4-15 

4.8 Other Governmental Activities ..............................4-15 

4.9 Emergency Management ..................................4-15 

4.10 General Flood Issues .....................................4-16 

4.11 Specific Flood Issues within the Manatee River Watershed ........4-18 

5.0 WATER SUPPLY ...............................................5-1 

5.1 Introduction ..............................................5-1 


April 26, 2001 

-ii-


5.2 Permitted Water Use.......................................5-2 

5.3 New Water Sources Initiative (NWSI)..........................5-3 

5.3.1 Reclaimed Water Use ................................5-5 

5.4 The Southern Water Use Caution Area ........................5-6 

5.5 Literature Reviewed ......................................5-10 

5.5.1 Water Supply Planning Studies ........................5-10 

5.5.2 Surface Water Studies Related to Water Supply ...........5-12 

5.5.3 Ground Water Studies Related to Water Supply ...........5-12 

5.6 Available Data...........................................5-12 

5.7 Outstanding Permitting Issues ..............................5-13 

5.8 Governmental Activities and Other Watershed Initiatives ..........5-13 

5.9 Water Supply Issues ......................................5-13 

5.10 References .............................................5-16 

6.0 NATURAL SYSTEMS ...........................................6-1 

6.1 Introduction ..............................................6-1 

6.2 Summary of Literature Reviewed .............................6-3 

6.3 Available Data ...........................................6-7 

6.3.1 Southwest Florida Water Management District .............6-7 

6.3.2 Department of Environmental Protection ..................6-8 

6.3.3 Florida Game and Fresh Water Fish Commission ...........6-8 

6.3.4 U.S. Fish and Wildlife Service ..........................6-8 

6.3.5 Miscellaneous .......................................6-8 

6.4 Permitting Issues..........................................6-8 

6.5 Land Acquisition for Resource Protection and Conservation ........6-9 

6.5.1 Conservation and Recreation Lands Program (CARL) .......6-9 

6.5.2 Save Our Rivers Program .............................6-9 

6.5.3 Preservation 2000 ...................................6-9 

6.5.4 Manatee County ...................................6-10 

6.5.5 Florida Communities Trust ............................6-10 

6.5.6 Nature Conservancy .................................6-10 

6.5.7 Trust for Public Lands ...............................6-11 

6.6 Alternative Initiatives for Natural Resources Protection ...........6-11 

6.6.1 State Management Programs ..........................6-11 

6.6.2 State Regulation Programs ...........................6-12 

6.6.3 County and Municipal Programs .......................6-12 

6.7 Minimum Flows ..........................................6-12 

6.7.1 Minimum Flows and Levels Approved Priority List and Schedule 

.................................................6-13 

6.8 Natural Systems: Issues, Strategies, and Actions ...............6-15 

6.8.1 Natural Systems Goals ...............................6-15 

6.9 References .............................................6-30 


April 26, 2001 

-iii-


Appendix: Manatee River Watershed Comprehensive Watershed Management Map 

Atlas (separate document) 


April 26, 2001 

-iv-

List of Figures 

Figure 1-1: CWM Watersheds in the Southwest Florida WMD ................1-5 

Figure 1-2: Comprehensive Watershed Management .......................1-6 

Figure 1-3: Estimated Funding by Activity and Source CWM Active Projects .....1-7 

Figure 1-4: Estimated Funding by Activity Manatee CWM ...................1-8 

Figure 3-1: Segmentation of the Manatee River Watershed for Discussion of Water 

Quality Issues .......................................... 3-14 


April 26, 2001 

-v-

List of Tables 

Table 2-1: Population Estimates and Projections ..........................2-5 

Table 2-2: 1995 Manatee County Employment by Major Industry .............2-6 

Table 2-3: 1995 General Land Use and Land Cover for the Manatee River Watershed. 

.......................................................2-7 

Table 2-4: 1990 Urban Land Use Within the FEMA 100-year Flood Zone ......2-8 

Table 2-5: 1995 Natural Systems in the Manatee River Watershed by the Florida Land 

Use Cover Classification System Code (FLUCCS) ................2-9 

Table 2-6: 2010 Generalized Future Land Use for the Manatee River Watershed 

......................................................2-10 

Table 2-7: 1995 Generalized Agricultural Land Use in the Manatee River Watershed 

......................................................2-11 

Table 2-8: 1992 Agricultural Land Use and Farm Profile for Selected Counties 

......................................................2-12 

Table 3-1: Mean total Nitrogen, phosphorus and suspended solids loadings to Tampa 

Bay from the Manatee River watershed for 1985-1991 and projected loading 

for the year 2010. Percentages of loadings from point sources, non-point 

sources and atmospheric deposition for 1985-1991 are also shown. Loading 

values are from Coastal Environmental, Inc. (1994) ............. 3-25 

Table 4-1: 1990 Urban Land Use (Existing) Within the FEMA 100-Year Flood Zone 

......................................................4-17 

Table 4-2: Urban Future Land Use Within FEMA 100-Year Flood Zone .......4-17 

Table 5-1: 1996 Permitted quantities by use type for the Manatee River watershed in 

million gallons per day. .....................................5-2 

Table 5-2: 1996 Estimated water use (SWFWMD, 1997). ...................5-5 

Table 5-3: Principal public supply utility use and permitted quantities, SWFWMD (RDB). 

.......................................................5-6 

Table 5-4: Manatee River CWM Reuse Summary. .........................5-6 


April 26, 2001 

-vi-

CWM Team Members 

This Plan is part of a continuing process. Over the past few years the participants listed 

below have met, reviewed information, distilled issues, discussed and negotiated a 

variety of potential actions and have generally benefitted from the process of 

discussion and sharing information. The efforts outlined in this Plan will continue with 

the support and energy of this team. A special thanks is necessary for those team 

members who authored parts of this document and provided comments on the various 

drafts. 

MANATEE RIVER COMPREHENSIVE WATERSHED MANAGEMENT TEAM 

Name 

Affiliation 

Harry Downing, Team Leader (2) 

Michael Beach 

Ray Blood 

Harold Bridges 

Robert Brown 

John Cumming 

March Duncan 

John Garrett 

Brandt Henningsen (4) 

Mike Hickey 

Jemy Hinton 

Janet Hoffman 

Douglas Leeper (1) 

Bruce MacLeod 

Ian McDonald 

Scott McGookey 

Steve Minnis 

Sia Mollanazar 

John Rickerson 

Carl Taylor 

Denise Tenuto 

John Walkinshaw 

Bart Weiss (3) 

Avera Wynne 

John Zimmerman 

Southwest Florida Water Management District 


Manatee County 

Smith & Gillespie Engineers 

Manatee County Environmental 

City of Bradenton 


Faulkner Farms 


City of Palmetto 

Florida Department of Environmental Protection 

Manatee County Planning and Development Dept. 


Manatee County Public Works Department 




Manatee County Public Works 


City of Bradenton 




Tampa Bay Regional Planning Council 

Manatee County Public Works Department 

1 - Team Leader, Water Quality AOR 3 - Team Leader, Water Supply AOR 

2 - Team Leader, Flood Protection AOR 4 - Team Leader, Natural Systems AOR 


April 26, 2001 C-1 

Team Membership

Executive Summary 

The Southwest Florida Water Management District (District or SWFWMD) has 

developed the Comprehensive Watershed Management (CWM) program to conduct 

water resource assessment and planning on a watershed basis. The CWM was 

established to promote careful evaluation of the regional status of water resources, with 

emphasis on the District’s (Mission) Areas of Responsibility (AORs): Water Supply; 

Flood Protection; Water Quality; and Natural Systems. Multi-disciplinary and multiagency 

teams were convened to develop and implement watershed management 

activities within each of the District’s eleven watersheds. This document represents the 

final draft of the CWM effort focusing on the Manatee River watershed. 

The Manatee River watershed extends over most of the northern and western parts of 

Manatee County with small portions extending into northern Sarasota County and 

southeastern Hillsborough County. The watershed is highly developed in the western 

region, particularly around the Cities of Bradenton and Palmetto. The watershed is 

comprised of two major river systems, the Manatee and Braden Rivers both of which 

have been impounded to develop the Lake Manatee and Bill Evers Reservoir which are 

used for potable supply purposes. Extensive agricultural areas within the watershed 

are rapidly being converted in to residential areas, particularly in the Braden River 

watershed. Strong population growth in this watershed continues to create numerous 

issues regarding land and water use. Maintaining minimum flows and levels, and good 

water quality are challenges that will carry into the future. 

This Plan seeks to integrate and coordinate the activities of the City of Bradenton, 

Manatee County, Florida Department of Environmental Protection (FDEP), SWFWMD, 

other government agencies, and private entities to promote comprehensive 

management of the water resources within the watershed. The Plan includes 

information on watershed projects which are underway, including the Wares Creek 

Flood Protection Project, the Manatee Agricultural Reuse System, and the 

establishment of Minimum Flows and Levels. Current and foreseeable watershed 

management problems and their solutions are also identified, based on review of 

existing studies, planning efforts, and active discussions at numerous CWM team 

meetings. Priority issues arising from this effort include: 

• the continued need for acquisition of information for assessment of 

watershed resources; 

• the need for greater coordination among existing multi-jurisdictional 

interest; 

• the identification of regional scale issues and benefits; 


April 26, 2001 E-1 

Executive Summary

• re-delineation of issues in terms of their impact on an AOR or AORs; 

• the feasibility and the availability of alternative options or solutions to 

identified problems; 

• public interest and awareness; and 

• opportunities for action. 

Priority actions identified by the Manatee River CWM team are outlined below. 

Water Quality 

1. Promote the collection, integration and analysis of water quality data for those 

stream segments located upstream of the control structures forming the Bill 

Evers Reservoir and Lake Manatee. 

2. Develop nutrient loading models for the watershed to support pollutant load 

reduction goals for the reservoirs and Tampa Bay. 

3. Investigate alternative methods for controlling algal growth within Lake Manatee 

and the Bill Evers Reservoir. 

4. Continue efforts regarding the monitoring and prevention of waterborne 

pathogens. 

Flood Protection 

1. Implementation of a data management system and associated data standards 

that allow the exchange of hydrologic and hydraulic information for the 

watershed. 

2. Development better floodplain information for the watersheds. Currently a 

watershed program is being developed for the Braden River watershed located 

upstream and including the Bill Evers Reservoir. 

3. Evaluate the design criteria for stormwater management areas that are also 

used for water supply sources. 

4. Development of basin-specific criteria for stormwater management planning. 

5. Support implementation of United States Army Corps of Engineers flood 

protection recommendations for the Wares Creek watershed. 


April 26, 2001 E-2 

Executive Summary

Water Supply 

1. Increase District participation with the Regional Planning Councils and local 

government planning departments. 

2. Support development of Minimum Flows and Levels Criteria for the Manatee and 

Braden Rivers, and for the Floridan Aquifer within the Southern Water Use 

Caution Area of the county. 

3. Continue implementation of the New Water Source Initiatives. 

4. Evaluate reuse of stormwater within the watersheds and its potential effect on 

Minimum Flows and Levels and existing surface water users. 

Natural Systems 

1. Update the identification and inventory of historical vs. current habitat 

distributions throughout the watershed. 

2. Correlate existing habitats with wildlife populations and distributions. 

3. Align state acquisition programs with priority wildlife habitat areas. 

4. Promote compatible recreational activities within publicly owned areas. 

5. Continue to implement pollutant reduction strategies that maintain the integrity of 

important ecosystems. 

Information supporting the prioritization of these needs is contained in this Manatee 

River CWM Plan in chapters focused on the four District AORs: water quality, flood 

protection, water supply, and natural systems. Projects presented within the Plan will 

be implemented through the combined efforts of federal, state, regional, and local 

governments as well as industry and private entities. 


April 26, 2001 E-3 

Executive Summary

Chapter 1 

1.0 INTRODUCTION 

1.1 Comprehensive Watershed Management 

The Comprehensive Watershed Management (CWM) initiative has been established to 

improve the management of water and related natural resources within the Southwest 

Florida Water Management District (SWFWMD or District). This initiative employs a 

watershed-based approach to resource management. Staff from a variety of disciplines 

and departments make up "watershed teams" that have been assigned to eleven 

primary watersheds (Figure 1-1). Local governments and other stakeholders within 

each watershed are also significant partners on these teams. The goals for the teams 

include: 

1. Collect, integrate and analyze the existing information pertinent to each 

watershed and create a data base for analytical purposes; 

2. Identify and prioritize existing and future water resource management issues 

relating to water supply, flood protection, water quality and natural systems 

(District Areas of Responsibility or “AORs”); 

3. Develop preventative or remedial management actions to address these 

resource management issues; 

4. Identify funding sources and partnerships to support action plan projects; 

5. Implement and monitor the effectiveness of selected actions and the overall 

process and recommend potential revisions. 

CWM represents an evolution in direction for the District, providing the opportunity to 

enhance coordinated action between the District, local governments and others. It is a 

science-based approach, including the application of Geographic Information System 

technology and other modeling tools within each watershed. 

Each team has been charged with the development of a watershed management plan 

reflecting the results of this process. The CWM watershed plans are complex in the 

breadth and variety of issues that they encompass, but simple in intent and design. 

They analyze the wealth of information available in each area, identify issues and 

recommend specific actions to address these issues. The fundamental elements of 

the plans are the chapters that identify issues in each of the District’s four AORs. 

Specific and realistic actions to address each issue are presented within each AOR. 

Completed CWM plans become a part of the District Water Management Plan through 


April 26, 2001 1-1 

Introduction

incorporation by reference. These plans reflect a “snapshot-in-time” for the watershed 

and will be updated on a periodic basis. 

1.2 Coordination With Local Governments and Other Agencies 

A significant element of the CWM initiative is the active involvement of the local 

government(s) together with the District within a watershed. The District and local 

governments share the premise that resource management incorporates the desire for 

sustainability. Consequently, the need to revise their respective policies from time to 

time is on a parallel tract. Scientific knowledge serves as the backbone to this process 

and allows us to achieve the desired watershed condition (Figure 1-2). Local 

governments have the greatest influence over future growth through their 

comprehensive plans and associated land development regulations. Partnering with 

local governments is essential to the success of the CWM initiative. Each CWM team 

will have active participation by the local government(s) within their watershed. This 

will include involvement in issue identification, development of preventative or remedial 

strategies and coordinated implementation. Agencies which are, or will be, requested 

to participate in the CWM process include the Department of Environmental Protection, 

Department of Agriculture and Consumer Services, the Florida Fish and Wildlife 

Conservation Commission, regional planning councils, Army Corps of Engineers, 

National Estuary Programs where appropriate, citizen groups and others. 

The CWM initiative helps to ensure that comprehensive, coordinated analysis and 

decision-making take place. It fosters closer cooperation and partnership between the 

District, local governments and other stakeholders to help preserve and improve the 

quality of watersheds as growth and development take place in the future. It allows 

rational and logical resolution of problems based on science. Integrated plans are 

developed with actual implementation of strategies involving multiple parties. 

1.3 Funding Commitments 

The District, in partnership with local, State and Federal governments, currently 

supports many significant water and related natural resource management projects and 

initiatives within each watershed. These efforts are currently contributing to effective 

management of water and related natural resources. Figure 1-3 summarizes the 

District’s current efforts for the eleven primary watersheds as of Fiscal Year 2000. This 

figure shows the types of projects and initiatives being funded, and the estimated 

sources of revenues. A total of approximately $896 million in water and related natural 

resource management projects, wholly or partially funded by the District, are currently 

underway within these watersheds. Of this amount, approximately $41.6 million are 

designated for Manatee River watershed projects (Figure 1-4). This does not include 

the many other resource management activities undertaken by local governments, 

FDEP and others. 


April 26, 2001 1-2 

Introduction

1.4 Implementation 

Each watershed management team has suggested specific and realistic actions and 

tasks. Recommendations that the District is responsible for implementing are 

prioritized by a District senior management team (Steering Committee). This 

Committee is responsible for determining priorities, directing them to the appropriate 

staff and board(s), and allocating staff time and resources. A significant means of 

implementation for the District is through the Basin boards’ cooperative funding 

programs. The recommendations from the CWM teams are incorporated into 

appropriate Basin board five-year plans, which are updated on an annual basis. 

The intent is that recommendations which fall within the implementation responsibility 

of local governments or others will be similarly prioritized and implemented. A formal 

partnership or Memorandum of Understanding between the District and participating 

parties may be proposed as a vehicle for coordinated implementation of these 

collaborative CWM planning efforts. 

CWM teams will review the implementation of recommended actions on a regular basis. 

These teams will report on implementation status for the Annual Report on the District 

Water Management Plan and provide a brief summary for each watershed. This 

information will be used within the Basin Board Five-Year Plans and in District 

accountability and performance reporting. 

1.5 Future of CWM - A Watershed-based Partnership Approach 

One of the most significant tools available to watershed teams is the District’s 

Geographic Information System (GIS). GIS is a database that is designed to efficiently 

store, retrieve, analyze and display mapped data. The ability to reference data by their 

location on the earth’s surface provides an effective means of integrating data from 

many diverse sources. The GIS currently allows staff to integrate data from ground and 

surface water models, the District’s Regulatory and Water Management Databases, 

and results from statistical analyses. This capability to integrate data from multiple 

sources allows staff to analyze previously undiscovered relationships between the 

data. For example, one might find a relationship between soil type, surface slope and 

vegetation cover that was not previously known. The GIS also provides a means of 

integrating disparate data such as census information and FEMA flood maps, allowing, 

for example, the analysis of per capita income of individuals living within the 100 year 

floodplain. The power of GIS lies in its ability to integrate numerical, statistical, 

engineering and spatial models and then dynamically depict and visually present 

scenarios. The GIS allows the CWM teams to analyze the best available information in 

such a way as to not only understand current conditions, but to also anticipate future 

conditions through scenario modeling. 

Utilizing the GIS as a tool in the comprehensive watershed management initiative 

represents an evolution in direction for the District, providing the opportunity to 


April 26, 2001 1-3 

Introduction

enhance coordinated action between the District, local governments and others. This 

GIS-based analysis and planning has, to-date, been applied only to a limited degree in 

selected watersheds. It is a major objective of the District that the use of the GIS, in 

conjunction with other modeling tools, be expanded and enhanced in a collaborative 

fashion with local governments and other participants for all eleven watersheds. 

Future updates to this Manatee River Comprehensive Watershed Management Plan 

will reflect progress made in further developing this GIS-based partnership approach. 


April 26, 2001 1-4 

Introduction

Figure 1-1: CWM Watersheds in the Southwest Florida WMD 


April 26, 2001 1-5 

Introduction

Figure 1-2: Comprehensive Watershed Management 


April 26, 2001 1-6 

Introduction

Figure 1-3: Estimated Funding by Activity and Source CWM Active Projects 


April 26, 2001 1-7 

Introduction

Figure 1-4: Estimated Funding by Activity Manatee CWM 


April 26, 2001 1-8 

Introduction

Chapter 2 

2.0 MANATEE RIVER WATERSHED DESCRIPTION 

2.1 Location 

The Manatee River Watershed is located almost entirely in Manatee County in the 

urbanizing Tampa Bay region of west-central Florida. The County covers 

approximately 742 square miles in land area and some 151 square miles of water. The 

Manatee River begins at an elevation of about 130 feet in marshes in the northeastern 

part of the County near Four Corners and flows approximately 45 miles in a westerly 

direction to southern Tampa Bay and the Gulf of Mexico. The river drains an area of 

about 360 square miles consisting mainly of Gulf Coastal Lowlands, hardwood 

swamps, marsh, and mesic flatwoods. 

The Manatee River Watershed extends over most of the northern and western parts of 

Manatee County with small portions extending into northern Sarasota County and 

southeastern Hillsborough County (Map 1). It is bounded to the north by the Little 

Manatee River watershed and coastal basins along Tampa Bay; to the east by the 

Peace River watershed and to the south and west by the Myakka River and Southern 

Coastal area watersheds, respectively. The Cities of Bradenton and Palmetto are the 

only incorporated areas within the watershed, while Parrish and Duette represent 

communities within the watershed. Other features of interest within the watershed 

include the Lake Manatee State Recreation Area, the Lake Manatee Reservoir, the 

Braden River and the Evers Reservoir, Duette Park, the Upper Manatee River Florida 

State Canoe Trail, and Rye Wilderness Park. 

2.2 Climate 

Manatee County has a humid, sub-tropical climate characterized by high mean annual 

rainfall and temperature. Summers are warm and humid and winters are mild as a 

result of low altitudes and the moderating effects of Tampa Bay and the Gulf of Mexico. 

National Weather Service data indicate that the mean annual air temperature in the 

County is about 72 o F and mean monthly temperatures range from 60 o F in winter to 80 o 

F in summer. Summer temperatures usually peak in the low to mid-90’s but are 

moderated by frequent afternoon convective thundershowers. Winter temperatures can 

exhibit considerable variation throughout a single day with freezing temperatures at 

night and early morning and “shirt-sleeve” weather in the afternoon. Cold weather 

generally lasts for only a few days at a time as cold fronts move through the region and 

daylight temperatures rarely remain below freezing. Average low temperatures are 

near 50 o F during the coldest months of December through February. 


April 26, 2001 2-1 

Chapter 2 - Watershed Description

Rainfall amounts in the County average about 54 to 55 inches per year with both 

seasonal and annual variation. April and November are the driest months as they are 

generally the least affected by local convective thundershowers or by rains preceding 

cold fronts . Late winter cold fronts cause a small increase in average rainfall in 

February and March. In a typical year, approximately 50-60 percent of the annual 

precipitation comes from convective (thunder) storms during the four-month period from 

June through September. Periods of extremely heavy rainfall associated with the 

passage of tropical low pressure systems may occur during summer and early fall. 

The maximum recorded daily rainfall was 10.8 inches on June 23, 1945. Annual 

rainfall has ranged between 93 and 29 inches during the period from 1911 to 1998 at 

the Bradenton weather station. (SWFWMD, WMDB) 

The dry season generally runs from October to May and often in the late spring, no 

measurable rainfall will occur for 60 days or more. The dry season and spring 

plantings increase the need for irrigation of truck crops and citrus, unfortunately, this 

coincides with the period of peak tourism. Therefore, October to May is the time of 

highest water use and consumption, both urban and agricultural. 

The Evapotranspiration (ET) rate in the region encompassing Manatee County is 

estimated to be about 39 inches per year with about 60 percent occurring from May to 

October. Evaporation is greatest in May and lowest in December (SWFWMD, 1988). 

About 70 percent of the region’s rainfall is lost to evapotranspiration and most of the 

rest runs off through sloughs, streams, and canals to end up in the Gulf of Mexico or 

used for water supply. Due to restrictive layers within the soil, very little of the rainfall 

goes to recharging the aquifers. 

2.3 Physiography 

The Manatee River Watershed lies within three physiographic provinces: the Polk 

Upland, the DeSoto Plain and the Gulf Coastal Lowlands from east to west. (White, 

1970). The Manatee River begins in the eastern part of the County in the Polk Uplands 

and flows down through the DeSoto Plain to the Gulf Coastal Lowlands in the west. 

The coastal lowlands are composed of nearly level plains while the DeSoto Plains and 

Polk Uplands have a gently rolling topography (White, 1970). The Polk Uplands 

contain areas referred to as the “Bone Valley” formation which is the area where 

phosphate and rare earths occur, although most mining activities in the region occur 

outside the watershed. 

The Gulf Coastal Lowlands province lies generally along the west coast and varies up 

to about forty miles inland in some places. Within the Manatee River Watershed, it 

extends about 10-15 miles inland, nearly to the Lake Manatee reservoir. The Gulf 

Coastal Lowlands are characterized by flat topography with elevations generally below 

40 feet and sandy, shelly, and silty sand soils. The DeSoto Plain extends eastward for 

about 3 miles in the northern portion of the watershed to about 10 miles in the southern 

portion and consists of generally white sandy soils at elevations from about 40' to 100'. 


April 26, 2001 2-2 


The Polk Upland occurs in the northeast quadrant of the County, eastward of the Lake 

Manatee Reservoir at elevations from approximately 100’ to 140’ and contains Bone 

Valley Formations (SWFWMD, 1988b). 

The soils found in Manatee County generally fall into four broad divisions: 

1: very poorly drained; 

2: poorly drained; 

3: somewhat poorly drained to moderately well drained; and 

4: poorly to moderately well drained. 

The very poorly drained soils include most of the nearly level black sand in swamps, 

tidal marshes, and river floodplains. These include the Delray-Floridana, Felda- 

Wabasso, and Tomoka Associations in freshwater lowlands. The Okeelanta and 

Estero-Wulfert-Kesson Associations are also very poorly drained but are found in salt 

marsh areas flooded daily by high tides. The natural vegetation consists mostly of 

mangrove but in some places it also consists of the seashore salt grass, batis, marsh 

hay, cordgrass, and oxeye daisy. The freshwater swamps and river floodplains that are 

flooded most of the year have native vegetation mostly of gum, oak, maple, hickory, 

bay, magnolia, cypress, wax myrtle, and some water tolerant grasses in the low areas. 

Low ridges support saw palmetto and scattered pine. Recharge is low in this division. 

Poorly drained soils of the flatwoods make up the majority of Manatee County. These 

nearly level, sandy soil associations are Waveland-Pomello-Myakka, Myakka- 

Waveland-Cassia, Eau Gallie-Floridana, and Wabasso-Bradenton-Eau Gallie. The 

natural vegetation consists of longleaf and slash pine and an undergrowth of saw 

palmetto, gallberry, wax myrtle, huckleberry, threeawn, and scattered fetter bushes. 

Many areas are used as rangeland, pasture, and for vegetables. Recharge is 

moderate to low in this division. 

The somewhat poorly to moderately well drained soils of the sand ridges and knolls are 

nearly level to gently sloping sandy soils. The majority of these soils occur in the 

higher elevations of northeast Manatee County and old dunes along the Gulf Coast. 

The soil associations are Pomello-Cassia-Duette and Tavares-Cassia-Zolfo. The 

native vegetation consists of oak, pine, saw palmetto, and perennial grasses. 

Infiltration is generally high in this division, but recharge is low. 

Poorly to moderately well drained soils of the coastal highlands are of the Canaveral- 

Beaches-Myakka Associations. This shelly sand in low areas is barren with some 

weeds and bushes. The higher areas are vegetated by pine, oak, saw palmetto, 

gallberry, wax myrtle, huckleberry, pineland threeawn, and scattered fetter bushes. 

Recharge is low to moderate in this division (SWFWMD, 1988a). 

2.4 Hydrogeology 


April 26, 2001 2-3 


Manatee County lies within the Southwest Central Florida Groundwater Basin and is 

underlain by a multi-layered freshwater aquifer system which includes the surficial, 

intermediate, and Floridan aquifer systems. Miocene to Recent age sands, phosphatic 

sands, silts, marls, limestones, and phosphorites of variable thickness overlie 

Cretaceous and Tertiary carbonate deposits. Miocene to Recent age deposits include 

in descending order, Pliocene to Recent age undifferentiated sands, the Pliocene Bone 

Valley Formation, and the Miocene Hawthorn Formation. 

The surficial aquifer occurs in the undifferentiated sands which overly the entire County 

and vary from less than 25 feet along the coastal areas to more than 50 feet in 

thickness in the northeastern areas of the County. These sands yield limited quantities 

of water, primarily for lawn irrigation, and are economically mined for their silica sand 

and shell hash content. The Bone Valley Formation, when present, has a variable 

thickness from 5 to 55 feet. It is rarely used for water supply but is mined for 

phosphate in the northeastern part of the County. 

The intermediate aquifer occurs in the Hawthorn Formation which is present 

throughout the County and varies in thickness from less than 200 feet to more than 350 

feet (Scott, 1981). The upper Hawthorn is a green sand and clay containing black 

phosphate grains. This upper unit is sometimes included with the Bone Valley ore 

matrix and targeted for open pit phosphate mining. The lower Hawthorn is yellow to 

white sand, clay, and limestone residual from carbonate rock. The fine sand is quartz 

and black or brown phosphate (Cathcart, 1966). Lenses of pure limestone, clay and 

sand exist throughout the formation and domestic water well production can be found in 

the porous limestone layers. 

Below the Miocene to Recent age deposits are a thick sequence of sedimentary rocks 

which comprise the Floridan aquifer system, the primary artesian aquifer throughout 

Florida. These chemically precipitated deposits of limestone and dolomite contain 

shells and shell fragments of marine origin which were deposited throughout the 

Tertiary period. These limestone units comprise the Tampa, Suwannee, Ocala, and 

Avon park formations. The Avon Park Formation is the deepest containing potable 

water. The Floridan system, which can be divided into the Upper and Lower Floridan 

aquifers throughout the County, thickens from approximately 1,200 feet in the northern 

areas of the County to more than 1,600 feet to the south. Generally, water quality in 

the Floridan Aquifer is good but it tends to deteriorate due to increasing mineralization 

as one moves south into the Everglades region (SWFWMD, 1988b). 

2.5 Population and Economy 

The Population of Florida has increased greatly during the past generation and 

Manatee County has experienced growth in excess of 43 percent in the decade 

between the 1980 and 1990 Census. The majority of this growth can be attributed to 

the large number of retirees and others attracted to the mild climate and recreational 

opportunities in west central Florida. Current estimates of population change indicate 


April 26, 2001 2-4 


that 99 percent of the growth in the County is due to migration. This is not surprising 

given that 28 percent of the population is over the age of 65 and the median age is 

43.1 (BEBR, 1994). Population growth in the County is expected to continue 

vigorously. In addition to the resident population, significant annual population 

fluctuations occur during “the season,” generally the period from Christmas to Easter. 

The County estimates that its overall population increases by an average of 24 percent 

(Manatee County, 1996), the City of Bradenton estimates its seasonal increase to be 

about 12 percent (Bradenton, 1999), and Palmetto about 22 percent (Manatee County, 

1996). 

The majority of residents in the County live within the relatively narrow corridor between 

the Gulf coast and I-75 which varies from about three to ten miles wide. Most future 

growth is expected to occur mainly in this corridor or a few miles further east. In order 

to address the possibility of future urban sprawl, the County has established a Future 

Development Area Boundary (FDAB) which extends eastward approximately to the 

Lake Manatee Reservoir. Future development outside the FDAB is expected to be at 

very low densities although there is some potential for the proliferation of 5 and 10-acre 

ranchettes. In general, Manatee County has been successful in keeping its growth 

patterns fairly compact by its policies of directing development by providing central 

water and sewer services to designated service areas and by discouraging 

development outside of those areas by not providing a full range of municipal services. 

Table 2-1: 

Population Estimates and Projections 

Area 1980 1990 1995 2000 2010 2020 

Manatee County 148,80 211,70 223,50 258,41 302,71 344,00 

City of Bradenton 30,288 43,779 47,679 52,752 61,549 N/A 

City of Palmetto 8,637 9,268 10,454 12,130 14,588 15,553 

Source: Manatee Co., 1996; Bradenton, 1999; BEBR, 1996 

Employment in Manatee County is dominated by service and retail industries, 

comprising about one half of the jobs covered by unemployment compensation. This is 

typical of counties with large populations of retirees, seasonal visitors, tourists and 

other immigrants. Surprisingly, manufacturing plays a significant role in the County and 

at about 13.8 percent of employment is well above the State average of 8.0 percent. 

This due in large part to the roles that agriculture and Port Manatee play in the regional 

economy; Tropicana Dole Beverages is the County’s largest manufacturing employer 

with about one-third of the employees in this sector. Staff Leasing, a temporary 

employment agency, is the County’s largest private sector employer (Manatee 

Economic Development Council) which points to the service and seasonal orientation 

of the local economy. 


April 26, 2001 2-5 


Table 2-2: 1995 Manatee County Employment by Major Industry 

Employment Category Number Percentage 

Agriculture 5,445 6.5 

Construction 3,326 4.0 

Manufacturing 11,568 13.8 

Transportation and Public Utilities 1,502 1.8 

Wholesale Trade 2,272 2.7 

Retail Trade 17,266 20.6 

Finance, Insurance, and Real Estate 2,872 3.4 

Services 29,289 34.9 

Government 10,082 12.0 

Other 331 0.4 

Total 83,953 

Source: BEBR, 1997 

2.6 Land Use, Growth and Development 

The District’s Geographic Information System (GIS) was used to provide a generalized 

view of the various land forms and uses within the watershed. The GIS is a powerful 

tool that can be used for a variety of analyses, from natural systems assessment to 

stormwater modeling. It should be noted that the data discussed below come from the 

map atlas which accompanies this report and are generalized. They are appropriate to 

provide a “big picture” view of the watershed but are not sufficiently detailed for 

planning purposes or project analysis due, in part, to how the data were “lumped” 

together. Also, it should be pointed out that there it is not always simple to categorize a 

particular piece of land or make specific inferences from the generalized acreages 

estimated. For example, the Florida Department of Transportation’s Land use, Cover 

and Forms Classification System (FLUCCS) has a category for rangeland which is 

generally considered to be “natural,” however, some of this land might be managed and 

used for pasturage. So is it agricultural or natural? Is a bahia grass sod farm cropland 

or pasture if there are cattle present? Project specific GIS analyses go into much more 

detail to handle such issues. 

Applying the FLUCCS codes to 1995 aerial photographs, urban and built-up lands 

comprised about 32,260 acres, or nearly 14 percent of the watershed total area (Table 

2-3, Map 2), agriculture comprised 92,979 acres (40.3%) of the watershed, rangeland 

some 32,942 acres (14.3%), upland forests some 25,696 acres (11.1%), and wetlands 

some 30,452 acres (13.2%). The vast majority of the urban and built up lands occur in 

the westernmost portions of the watershed, in the cities of Bradenton, Palmetto, and 

adjacent unincorporated areas. This follows the typical historical pattern of 


April 26, 2001 2-6 


development where coastlines and riverways were developed first as they served as 

initial transportation corridors. Later development of the railroads and highway system 

reinforced this pattern in coastal counties due to the physical barriers of the waterways, 

the need to serve existing and growing populations, and the high value and desirability 

of waterfront areas. 

Table 2-3: 

1995 General Land Use and Land Cover for the Manatee River 

Watershed. 

Land Use - Land Cover Total Acres Total Percent 

Urban and Built-up 32,259.90 14.0 

Agriculture 92,979.48 40.3 

Rangeland 32,941.76 14.3 

Upland Forests 25,696.13 11.1 

Water 12,773.06 5.5 

Wetlands 30,452.22 13.2 

Barren Land 119.35 0.05 

Transportation, Communication and Utilities 3,384.89 1.5 

TOTAL 230,606.79 

Source: SWFWMD GIS, 1999 

A significant portion of the development in the County, as elsewhere in Florida, occurs 

in floodprone areas as designated by the Federal Emergency Management 

Administration (FEMA). According to the generalized GIS data used to generate Map 

12, some 4,045 acres or about 1.8 percent of the watershed is within a 100-year flood 

zone and of these areas, nearly 3,100 acres or 76 percent are designated as 

residential areas. Improper development in these areas can cause threats to life, 

property, and the quality of the environment. Additionally, there are other areas prone 

to flooding after heavy rainfall which are not designated by FEMA as they may be 

inland away from the coast and rivers; they may not have been accurately mapped; 

they may be in closed drainage basins; or they may suffer from localized flooding due 

to nearby development changing historical stormwater flow patterns or other specific 

local conditions. 


April 26, 2001 2-7 


Table 2-4: 

1990 Urban Land Use Within the FEMA 100-year Flood Zone 

Land Use Total Acres Percent 

Residential < 2 units/acre 671.11 16.59 

Residential 2 to 5 units/acre 737.88 18.24 

Residential >5 units/acre 1,427.22 35.29 

Commercial and Services 243.97 6.03 

Industrial 40.27 1.00 

Extractive 16.62 0.41 

Institutional 95.36 2.35 

Recreational 128.04 3.17 

Open Land 684.29 16.92 

TOTAL 4,044.76 100.00 

Sources: Southwest Florida Regional Planning Council (generalized future land use data), 1996 

Federal Emergency Management Agency’s Flood Insurance Rate Maps, misc. years 

The Manatee River Watershed reflects a wide variety of land uses and conversions of 

natural lands, principally as a result of urban, suburban, commercial, industrial and 

agricultural development. Map 2 shows the generalized land uses and land cover in 

1995 and Map 4 shows the distribution of agricultural land use/cover. Due to past 

development practices, much of the natural systems in the watershed have been 

impacted. Map 14 depicts the generalized distribution of natural systems within the 

CWM watershed. About 38 percent of the watershed is considered “natural.” Of these 

natural areas, rangeland comprises about 14.3 percent of the watershed, pine 

flatwoods and other natural upland forests about 11.1 percent, and wetlands about 13.2 

percent of the watershed. Other natural areas and habitats comprise only a small part 

of the total watershed area. 


April 26, 2001 2-8 


Table 2-5: 

1995 Natural Systems in the Manatee River Watershed by the Florida 

Land Use Cover Classification System Code (FLUCCS). 

FLUCCS Code - Land Cover Total Acres Percent of 

Watershed 

300 Rangeland 32,941.76 14.28 

400 Upland Forests 25,696.13 11.14 

410 Upland Coniferous Forest 16,690.08 7.24 

411 Pine Flatwoods 15,117.40 6.56 

420 Upland Hardwood Forest 8,446.38 3.66 

600 Wetlands 30,452.22 13.21 

610 Wetland Hardwood Forests 14,940.10 6.48 

611 Bay Swamp 18.40 0.01 

612 Mangrove Swamp 431.73 0.19 

615 River/Lake Swamp 14,467.77 6.27 

620 Wetland Coniferous Forest 329.39 0.14 

621 Cypress 291.77 0.13 

630 Wetland Forested Mix 3,284.23 1.42 

641 Freshwater Marsh 8,037.77 3.49 

642 Saltwater Marsh 1,291.64 0.56 

643 Wet Prairies 1,897.24 0.82 

644 Aquatic Vegetation 447.45 0.19 

651 Tidal Flats 217.84 0.09 

653 Intermittent Ponds 6.56 0.003 

Total Natural Systems 89,090.11 38.63 

(SWFWMD GIS, 1999). NOTE: Codes are at different levels of classification. Total is from 

Level I classification (300, 400, 600) 

As part of the local government comprehensive planning process, future land use 

needs are estimated on the basis of projected population growth and appropriate levels 

of development required to adequately serve them in terms of housing, employment, 

services, shopping, etc. Future land use within the Manatee River Watershed is 

expected to be similar to existing uses with some notable exceptions. Primarily as a 

result of the desire to protect water quality in its potable water source, the Lake 

Manatee and Evers Reservoirs, the County has designated a watershed overlay district 

for the Lake Manatee Watershed in which land uses and development proposals must 

undergo a higher level of scrutiny in the development permitting process and they must 

adhere to higher performance standards in terms of setbacks, minimum design criteria 

for stormwater management systems, buffering, and other criteria specified in the 


April 26, 2001 2-9 


County’s Land Development Regulations. In order to further protect its water supply, 

the County has purchased mining lands in the upper watershed to prevent future 

mining on them; it has bought other property in the watershed to protect it from 

development; and it has worked closely with the District to identify and acquire 

appropriate lands through the Save Our Rivers/ Preservation 2000 (SOR/P2000) and 

Conservation and Recreation Lands (CARL) programs. The District has identified 

about 22,930 acres as land acquisition priorities in the Manatee River Watershed and, 

to date, has purchased about 6,973 acres under SOR/P2000. (SWFWMD, 2000) 

Table 2-6: 

2010 Generalized Future Land Use for the Manatee River Watershed 

Land Use - Land Cover Total Acres Percent of Watershed 

Agriculture 94,637.26 41.0 

Estates Residential 13,841.98 6.0 

Single Family Residential 54,683.67 23.7 

Multi-family Residential 20,543.07 8.9 

Industrial 5,070.04 2.2 

Commercial 6,638.78 2.9 

Preservation 24,034.84 10.4 

Water 11,169.32 4.8 

TOTAL 230,618.88 

Source: Southwest Florida Regional Planning Council, 1993. 

Agriculture is by far, the largest single land use in Manatee County and within the 

Manatee River Watershed. Agriculture in Manatee County consists primarily of 

vegetable crops, citrus, and livestock. Overall, the 1992 Census of Agriculture showed 

that agricultural land comprised nearly 300,000 acres within the County and about 

92,980 acres lie within the watershed (Map 4). Agricultural land represents roughly 40 

percent of the total land area of the County and also of the watershed (Tables 2-3, 2-7). 

Of that total, about 75,073 acres (about 33 percent of the watershed) are in cropland 

and pastureland and about 13,951 acres (6 percent) are in tree crops, mainly citrus. In 

1992, Manatee County ranked sixth in the state in the value of all agricultural products 

sold and eighth in average per farm sales. It ranked sixth in the state in 1992 for the 

value of crop sales, and ranked ninth in total citrus acreage (BEBR, 1995). According 

to the Florida Agricultural Statistics Service, in 1994 Manatee County had about 10,800 

acres in tomatoes, 2,800 acres in watermelons, and 1,070 acres in cucumbers. This 

represents about 23.4 percent, 44.8 percent, and 26.4 percent, respectively, of the 

1994 statewide acreage. 

The greatest change occurring within the County since the 1987 Agricultural Census 

has been increases in harvested and irrigated cropland and an increase in citrus 


April 26, 2001 2-10 


production. During this period, total land in agriculture declined by some 30,000 acres 

(9%) and the number of farms declined by 38 (5%) while cropland acreage increased 

by about 16,600 acres (18%), citrus increased by about 10,000 acres (58%) and 

pasture lands decreased by about 30,400 acres (14%) [1992 Census of Agriculture]. 

Table 2-8 provides additional information profiling agriculture. 

Table 2-7: 

Land Use 

1995 Generalized Agricultural Land Use in the Manatee River 


Acreage 

Lands Percent of 

Agric. in Watershed 

Percent of 


Cropland and Pastureland 49,576.37 53.3 21.5 

Row Crops 25,497.30 27.4 11.1 

Tree Crops 13,951.83 15.0 6.1 

Feeding Operations 720.52 0.8 0.3 

Nurseries and Vineyards 510.08 0.6 0.2 

Specialty Farms 382.11 0.4 0.2 

Rural Open Lands 2,341.27 2.5 1.0 

Total 92,979.48 40.32 

Source: SWFWMD GIS, 1995 


April 26, 2001 2-11 


Table 2-8: 

1992 Agricultural Land Use and Farm Profile for Selected Counties 

Florida Manatee Sarasota Charlotte DeSoto Hardee 

Number of Farms 35,204 728 328 214 804 1,169 

Average Farm Size 306 412 461 1,062 416 280 

Land in Farms (acres) 10,766,077 299,699 151,242 227,202 334,623 327,611 

Total Cropland 3,841,505 109,143 25,290 35,622 89,670 99,729 

Harvested 2,400,704 61,950 7,832 21,927 62,250 61,233 

Irrigated 1,782,680 54,568 5,207 17,882 58,806 53,777 

Pasture 972,995 31,416 17,217 D 24,837 34,362 

Vegetable Crops 299,867 21,695 1,266 1,335 3,549 2,769 

Orchards 914,642 26,036 3,281 15,489 55,466 51,295 

Woodland nonpastured 836,412 15,448 1,689 D 9,813 8,876 

Other Land nonpastured 545,851 15,757 3,583 6,331 12,789 13,103 

Pastureland all types 6,515,304 190,767 137,897 191,048 247,188 240,265 

Average Sales per Farm($) 149,586 288,277 57,631 177,117 160,020 109,255 

Average Value of Land & 

Buildings per Farm 619,265 796,187 202,461 1,310,837 848,575 569,627 

Avg Equip Value/Farm 40,898 72,941 35,856 40,812 42,272 35,448 

Total Market Sales ($1000) 5,266,033 209,865 18,903 37,903 128,656 127,720 

Vegetable Crops 1,053,071 98,068 3,851 2,727 8,142 6,310 

Fruits, Nuts, etc. 1,383,465 41,392 4,768 24,380 102,046 77,151 

Nursery & Greenhouse 1,024,315 44,058 3,960 3,634 2,815 11,582 

Livestock, Poultry, etc. 1,068,613 22,124 5,877 5,975 15,565 32,462 

SOURCE: 1992 Census of Agriculture, U.S. Department of Commerce, Bureau of the Census 

2.7 Transportation 

There are several major transportation corridors which pass through the Manatee River 

watershed. North-south routes lie mainly in the urbanized western portions around 

Bradenton. U. S. Highway 41, a.k.a. the Tamiami Trail, is the western-most of these 

corridors and has long served as the main local north-south route. It was originally the 

main highway before the interstate system was developed and was instrumental in 

bringing growth and development to the coastal areas of the region. U. S. Highway 301 

is similar in use and history to the Tamiami Trail although it lies somewhat more to the 

east. Interstate Highway 75 is the major north-south roadway in use today and 

provides the bulk of through traffic and commerce, connecting Manatee County with 

areas both north and south as well as to Ft. Lauderdale on east coast via the I-75 

crossing of the Everglades known as Alligator Alley. Farther east in the central portion 

of the watershed, County Road 675 crosses the Manatee River above Lake Manatee 

and Verna Bethany Road crosses the river about two miles to the east of CR 675. To 

the east of the watershed, Wauchula Road and Duette Road skirt the boundaries of the 

watershed. 


April 26, 2001 2-12 


Several major east-west corridors connect Manatee County to the interior of the State. 

State Road 62 in the northern part of the watershed connects Parrish to the phosphate 

mining areas in central Hardee County. State Road 64 connects the City of Bradenton 

to Zolfo Springs in central Hardee County and eastward to Avon Park in Highlands 

County. State Road 70 connects Bradenton to the City of Arcadia, the County seat of 

DeSoto County, and eventually to Florida’s east coast at the City of Fort Pierce. As 

State Road 70 is part of the Florida Intrastate Highway system, long term transportation 

plans call for its widening and improvement to facilitate movement between Florida’s 

coastal areas and interior. 

In addition to the highway system, Manatee County is served by the Sarasota- 

Bradenton International Airport which lies just to the south of the watershed overlapping 

the Sarasota-Manatee County line; Port Manatee in the extreme northwest corner of 

the County on Tampa Bay; and the CSX Railroad which crosses the Manatee River 

between the U.S. 301 and U.S. 41 bridges. 

2.8 References 

City Council of Bradenton, Florida, 1999. City of Bradenton (Proposed) 

Comprehensive Plan, Bradenton, Florida. 

Bureau of Economic and Business Research (BEBR). 1994. 1994 Florida Statistical 

Abstract. Bureau of Economic and Business Research, College of Business 

Administration, University of Florida, University Press of Florida, Gainesville, 

Florida. 

BEBR 1996. 1996 Florida Statistical Abstract. Bureau of Economic and Business 

Research, College of Business Administration, University of Florida, University 

Press of Florida, Gainesville, Florida. 

BEBR 1997. 1997 Florida Statistical Abstract. Bureau of Economic and Business 

Research, College of Business Administration, University of Florida, University 

Press of Florida, Gainesville, Florida. 

Cathcart. J. B., 1966. Economic Geology of the Fort Meade Quadrangle Polk and 

Hardee. U. S. Geological Survey Bulletin 1207. 

Florida Agricultural Statistics Service. 1996. Citrus Summary 1994-95. Florida 

Department of Agriculture and Consumer Services, Division of Marketing and 

Development, Florida Agricultural Statistics Service, Orlando, Florida. 

Florida Agricultural Statistics Service. 1996. Livestock, Dairy and Poultry Summary 

1995. Florida Department of Agriculture and Consumer Services, Division of 

Marketing and Development, Florida Agricultural Statistics Service, Orlando, 



April 26, 2001 2-13 


Florida Agricultural Statistics Service. 1996. Vegetable Summary 1994-95. Florida 

Department of Agriculture and Consumer Services, Division of Marketing and 

Development, Florida Agricultural Statistics Service, Orlando, Florida. 

Florida Department of Environmental Protection (FDEP). 1996. 1996 Water Quality 

Assessment for the State of Florida, Section 305 (b) Report, CD-ROM. 

Tallahassee, Florida. 

Florida Department of Transportation, 1985. Florida Land use, Cover and Forms 

Classification System, Procedure No. 550-010-001, State Topographic Bureau, 

Thematic Mapping Section, FDOT. Tallahassee, FL. 

Manatee County Board of County Commissioners. 1996. Manatee County Evaluation 

and Appraisal Report. Bradenton, Florida. 

Manatee Economic Development Council, 1996. Informational brochure. 

Scott, T.M. and P.L. MacGill, 1981, The Hawthorne Formation of Central Florida, 

Florida Bureau of Geology, R.I. 91. 

Southwest Florida Regional Planning Council (SWFRPC). 1993. Generalized Future 

Land use Map of the State of Florida. Southwest Florida Water Management 

District Geographic Information System (GIS), Brooksville, Florida. 

Southwest Florida Water Management District (SWFWMD), K.K. Keller, 1988. 

Distribution of Evapotranspiration Within the Southwest Florida Water 

Management District. SWFWMD, Brooksville, Florida. 

SWFWMD. 1988a. Geographic Information System (GIS) soils data obtained from the 

USDA Natural Resources Conservation Service (formerly the Soil Conservation 

Service) from county soil surveys and aggregated by hydrologic group. 

Brooksville, Florida, 

SWFWMD. 1988b. Ground-Water Resource Availability Inventory: Manatee County, 

Florida. Brooksville, Florida. 

SWFWMD. 1998. “Southern Water Use Caution Area Information Report.” 

Brooksville, Florida. 

SWFWMD. 1998a. Water management Lands Trust Fund -Save Our 

Rivers/Preservation 2000 1998 Five-Year Plan. Brooksville, Florida. 

SWFWMD. 1999. Geographic Information System (GIS). Land use and cover dated 

interpreted from aerial photography taken from 10/94 to 5/95. 


April 26, 2001 2-14 


SWFWMD. 2000. Water management Lands Trust Fund -Save Our 

Rivers/Preservation 2000 2000 Five-Year Plan. Brooksville, Florida. 

SWFWMD. WMDB. District Water Management Data Base. (Computer data base, 

regularly updated) 

United States Department of Commerce, Bureau of the Census. 1992. 1992 Census 

of Agriculture. Washington, D. C. 

White, W. H. 1970. The Geomorphology of the Florida Peninsula. Geological Bulletin 

No. 51. Bureau of Geology, Department of Natural Resources. Tallahassee, 



April 26, 2001 2-15 


Chapter 3 

3.0 WATER QUALITY 

3.1 Water Quality Goals and Management in the Manatee River Watershed 

3.1.1 Section Overview 

The Manatee and Braden Rivers are important sources of potable water for the 

residents of Manatee and Sarasota Counties. The rivers and their tributaries also 

serve the aesthetic and recreational needs of the human population, and provide 

habitat for numerous plant and animal species. Maintaining good water quality 

throughout the watershed will help preserve the biological integrity of these riverine 

systems, ensure their continued use as drinking-water supplies, and maximize their 

potential for enhancing the lives of all Floridians. 

This section provides an overview of various institutional and legislative goals that 

provide guidance for water quality protection in the Manatee River watershed, and also 

includes a summary of programs and agencies actively involved in regional water 

quality management. 

3.1.2 Water Quality Goals and Standards 

Protection of water quality in the Manatee River watershed is provided by an 

environmental law system with roots at the federal, state, and local level. The United 

States Environmental Protection Agency (USEPA) administers numerous programs 

established by federal law which provide for the protection of the nation’s water 

resources. Some administrative and regulatory authority has been delegated by the 

USEPA to the Florida Department of Environmental Protection (FDEP), an organization 

authorized by state law to protect, conserve, and manage Florida’s environment and 

natural resources. The FDEP has authorized the Southwest Florida Water 

Management District (SWFWMD) to assume the lead role in several water 

management areas, including stormwater management, water use permitting, and 

Surface Water Improvement and Management (SWIM) planning and implementation. 

Ordinances and management plans adopted by Manatee County, Sarasota County and 

local municipalities provide additional governmental oversight of water quality 

protection. 

Water Quality Goals of the Federal Clean Water Act 

Current federal water pollution control law, commonly referred to as the Clean Water 

Act (Title 33, Chapter 26, United States Code), includes specific objectives and goals 

pertaining to water quality. The Act’s stated objective; “to restore and maintain the 


April 26, 2001 3-1 

Chapter 3 - Water Quality

chemical, physical and biological integrity of the nation’s waters”, is to be achieved 

through various goals, including: 

• the elimination of the discharge of pollutants into navigable waters; 

• the achievement of water quality “which provides for the protection and 

propagation of fish, shellfish, and wildlife and provides for recreation in 

and on the water”; 

• the prohibition of the discharge of toxic pollutants in toxic amounts; 

• the provision of federal financial assistance for the construction of publicly 

owned waste treatment works; 

• support for the development of regional waste treatment planning 

processes to “assure adequate control of sources of pollutants in each 

State”; 

• support for research and development of “technology necessary to 

eliminate the discharge of pollutants into navigable waters, waters of the 

contiguous zone, and the oceans; and 

• support for the development and implementation of programs for the 

control of nonpoint sources of pollution. 

Water Quality Goals of the Florida Air and Water Pollution Control Act 

Water quality goals for the state of Florida are expressed in the Florida Air and Water 

Pollution Control Act (Section 403, Florida Statutes) as follows: 

“It is declared to be the public policy of this state to conserve the waters 

of the state and to protect, maintain, and improve the quality thereof for 

public water supplies, for the propagation of wildlife and fish and other 

aquatic life, and for domestic, agricultural, industrial, recreational, and 

other beneficial uses and to provide that no wastes be discharged into 

any waters of the state without first being given the degree of treatment 

necessary to protect the beneficial uses of such water.” (Section 403.021, 

Florida Statutes). 

State Surface Water Quality Standards 

Class-specific criteria for water quality of the surface waters of Florida are included in 

Chapter 62-302 of the Florida Administrative Code (F.A.C.). Surface water body 

classifications are based on designated use, and are defined as: 

Class I 

Class II 

Class III 

Class IV 

Class V 

Potable water supplies; 

Shellfish propagation or harvesting; 

Recreation propagation, and maintenance of a healthy, wellbalanced 

population of fish and wildlife; 

Agricultural water supplies; and 

Navigation, utility, and industrial use. 


April 26, 2001 3-2 


These classifications are associated with standards or criteria for a wide variety of 

chemical and physical parameters that affect water quality. Chapter 62-302, F.A.C. 

also includes a listing of water bodies designated as Outstanding Florida Waters or 

Outstanding National Resource Waters. Water quality in these systems is afforded 

additional protection as described in various sections of the F.A.C. 

The Manatee River is classified as a Class III water body from its mouth (designated as 

a line from Emerson Point to Meade Point) upstream to the Rye Road bridge. 

Segments of the river above the Rye Road bridge, including Lake Manatee, tributaries 

entering Lake Manatee, and tributaries entering the upstream reaches of the river are 

classified as Class I waters. Portions of the river, including regions associated with the 

Lake Manatee State Recreation Area, and Emerson Point are designated as 

Outstanding Florida Waters. The Braden River is classified as a Class III water body 

from its mouth upstream to the Bill Evers Reservoir dam. The reservoir, the section of 

river upstream to State Road 675, and most of the length of all tributaries entering the 

river above the dam are classified as Class I waters. Upper reaches of many of these 

tributaries are classified as Class III waters. No water bodies in the Manatee River 

watershed are designated as Outstanding National Resource Waters. 

State Ground Water Quality Standards 

Class-specific criteria for water quality of ground water in the Florida are included in 

Chapter 62-520, F.A.C. Ground water classifications are based on designated use, and 

are defined as: 

Class F-1 

Class G-1 

Class G-2 

Class G-3 

Class G-4 

Potable water use, ground water in a single source aquifer (in 

Flagler County), as described in Rule 63-520.460, F.A.C. which 

has a total dissolved solids content of less than 3,000 mg/l and 

was specifically reclassified as Class F-1 by the Environmental 

Regulation Commission (Commission); 

Potable water use, ground water in a single source aquifer which 

has a total dissolved solids content of less than 3,000 mg/l; 

Potable water use, ground water in aquifers which has a total 

dissolved solids content of less than 10,000 mg/l, unless otherwise 

classified by the Commission; 

Non-potable water use, ground water in unconfined aquifers which 

has a total dissolved solids content of 10,000 mg/l or greater, or 

which has total dissolved solids of 3,000-10,000 mg/l and either 

has been reclassified by the Commission as having no reasonable 

potential as a future source of drinking water, or has been 

designated by the Department as an exempted aquifer pursuant to 

Rule 62-28.130(3), F.A.C.; 

Non-potable water use, ground water in confined aquifers which 

has a total dissolved solids content of 10,000 mg/l or greater. 


April 26, 2001 3-3 


These classifications are associated with standards or criteria for chemical and 

physical parameters that affect water quality. Class G-1 and G-2 potables sources are 

required to meet primary and secondary drinking water standards. Ground water quality 

standards and guidance levels for a wide variety of water quality parameters are 

provided in a FDEP (1994b) document, titled “Ground Water Guidance 

Concentrations”. 

Water Quality Goals of the Southwest Florida Water Management District 

Water quality goals of the SWFWMD are outlined in the District Water Management 

Plan (SWFWMD 2000). Throughout its jurisdiction, the District seeks “to protect water 

quality by preventing further degradation of the water resource and enhancing water 

quality where appropriate.” 

Water Quality Goals of the Manatee County Government 

Goals and objectives for water quality protection in the Manatee River watershed are 

incorporated into the Manatee County Comprehensive Plan (Manatee County 1995), 

and include: 

• Protection of surface and groundwater resources at the lowest possible 

cost for potable water use, recreational use, and the provision of aquatic 

habitat for native flora and fauna; 

• Maintenance or improvement of water quality and quantity in Lake 

Manatee and the Bill Evers Reservoir Watershed Overlay Districts for the 

purpose of ensuring a continued supply of drinking water at the lowest 

possible cost; 

• Maintenance or enhancement of water quality and transparency of 

surface waters and protection of ground water quality through natural 

resource and land use programs to: contribute to continued cleanup of 

Tampa Bay and Sarasota Bay; ensure clean water for passive recreation; 

maintain water quality for potable wells; and enhance natural aquatic 

habitat; and 

• Prevention of the release of toxic amounts of hazardous substances and 

the pollution of the land, water, and air resources of Manatee County. 

3.1.3 Water Quality Management and Sources of Water Quality Data for the 

Manatee River Watershed 

A diverse array of governmental agencies from the local to federal level are actively 

engaged in water quality monitoring and management programs in the Manatee River 

watershed. Data are also collected by non-governmental organization for compliance 

with local, state and federal regulations and permits. The following summary of 


April 26, 2001 3-4 


programs and activities provides an indication of the complexity of water quality 

management and issues in the watershed. 

Comprehensive Watershed Management Initiative 

The Comprehensive Watershed Management (CWM) initiative provides a forum for the 

development of solutions to water quality issues and problems in each of the thirteen 

watersheds comprising the jurisdictional boundary of the District. The Manatee River 

CWM Team, formed as a result of this initiative, provides the means for coordinated 

achievement of local, state and federal water quality goals for the Manatee River 

watershed. 

Drinking-Water Supply Monitoring 

Water quality is monitored at various sites within the watershed in support of drinking 

water production by the Manatee County Public Works Department and the City of 

Bradenton Water Treatment Plant. Data is collected for compliance with drinking water 

and water use regulations, as well as for management of water quality within Lake 

Manatee and the Bill Evers Reservoirs, the two surface water sources which serve as 

the primary source of drinking water for the region. 

The Manatee County Public Works Department monitors algal abundance in Lake 

Manatee several times weekly, and collects surface water quality data at eight sites in 

the Lake Manatee reservoir on a monthly basis. Additional surface-water monitoring is 

conducted at fixed and “roving” stations in the watershed above the reservoir. The 

County also routinely monitors water quality of ground water which is pumped from the 

Floridan Aquifer for use as a secondary source for drinking-water. The City of 

Bradenton Water Treatment Plant monitors algal abundance in the Bill Evers Reservoir 

three times weekly. Additional monitoring, including the determination of nutrient and 

copper concentrations, is conducted on a monthly basis at sites within and just 

upstream from the reservoir (to the I-75 bridge). Copper concentration is monitored 

monthly at seven additional upstream sites and in sediment samples collected from the 

reservoir. The City also collects water quality data for the lower Braden River segment 

for compliance with a water use permit issued by the SWFWMD. 

The Clean Water Act currently requires each state to establish a Source Water 

Assessment and Protection (SWAP) program to assess potential sources of pollution to 

public drinking water supplies. These programs are required to identify all public water 

system intakes, delineate source water supply areas, inventory known and potential 

contaminant sources within the source water supply areas, determine the susceptibility 

of water supplies to contamination from identified contaminant sources, and to include 

a mechanism for making program results available to the public. The FDEP has 

submitted a SWAP program proposal to the USEPA, and anticipates developing and 

implementing this program statewide in the next few years. 


April 26, 2001 3-5 


National Pollution Discharge Elimination System Permitting 

Point source discharges to surface waters are permitted by the USEPA National 

Pollutant Discharge Elimination System (NPDES). In Florida, NPDES permitting is 

administered by the FDEP, with assistance from local governments. Currently, there 

are four major NPDES-permitted discharges in the watershed. Effluent from the City of 

Bradenton domestic wastewater treatment facility, Tropicana Industries industrial waste 

treatment facility, and mixed cooling water and storm water the SI Palmetto facility is 

discharged into the Manatee River. SMR Aggregates discharges effluent from a 

wastewater treatment plant into the Braden River. 

United States Geological Survey Monitoring 

The United States Geological Survey (USGS) currently maintains eight gaged surface 

water stations in the Manatee River watershed. Water quality data at gaged stations 

are typically collected only for specific projects, but a database for current and 

previously gaged stations in the Manatee River watershed extends back to the 1960s. 

The USGS also collects information on ground water quality in the Manatee River 

watershed region. These data are typically collected for specific projects, such as the 

recently completed study of water quality in the Bill Evers Reservoir (Ward Lake) 

watershed (Trommer et al. 1999). 

Ambient Surface and Ground Water Quality Monitoring 

The Manatee County Environmental Management Department routinely collects water 

quality data from sites throughout the Manatee River watershed (Manatee County 

Environmental Management Department 1998). The County’s Regional Ambient 

Monitoring Program (RAMP) for estuarine habitats includes collection of water quality 

data for sites in the Manatee River below the mouth of the Braden River. The Surface 

Water Ambient Monitoring Program (SWAMP) includes monthly monitoring at nineteen 

fixed stations in the Manatee and Braden River watersheds, principally in freshwater 

segments of the river systems. Additional water quality data is collected in support of 

specific projects, typically in localized regions of the watershed and for limited periods. 

Since 1984, the SWFWMD has maintained a ground water monitoring network within 

the boundaries of the District. This program has since been expanded to include 

surface water quality monitoring, and is currently known as the Water Qaulity 

Monitoring Program (WQMP). Surface water quality monitoring in the Manatee River 

watershed is currently not conducted as part of the WQMP; ground water monitoring in 

the watershed includes collection of water quality data from ten surficial aquifer wells, 

eleven intermediate aquifer wells and thirty Floridan aquifer wells in Manatee County 

(SWFWMD 1996). 

The FDEP is currently developing an Integrated Water Resource Monitoring (IWRM) 

Program for the evaluation of water quality in Florida lakes, streams, and aquifers. 

This program is envisioned as a multi-tiered process that will involve routine monitoring 

throughout the state to determine trends in the quality of Florida’s water resources, 

localized monitoring to determine the status of and provide support for effective 


April 26, 2001 3-6 


management options for specific water bodies, and site-specific monitoring to assure 

compliance with permitted activities. 

State Water Quality Assessment Program and Development of Total Maximum 

Daily Loads 

Every two years, the FDEP produces a watershed-based summary assessment of the 

quality of Florida’s water resources for submission to the USEPA in accordance with 

Section 305(b) of the Clean Water Act. For its most recent version of this report, the 

FDEP (1996) relied on water-chemistry information in the USEPA’s STORET database, 

FDEP’s quantitative biological data, incidents of violation of state water quality criteria 

for conventional pollutants and toxicants, information from the agency’s qualitative 

Nonpoint Source Assessment (FDEP 1994a), and fish consumption advisories. If 

available, recent data (1990-1995) were used, otherwise historical (1980-1989) data 

were evaluated. Information contained in the 1996 state water quality assessment was 

used to develop a list of waters (commonly referred to as the 303(d) list) which do not 

meet state water quality standards or do not support their designated uses (e.g., 

potable water supply, recreation propagation, etc.). This list, developed in accordance 

with Section 303(d) of the Clean Water Act identifies impaired water bodies for which 

Total Maximum Daily Loads (TMDLs) must be developed on a priority basis. Total 

Maximum Daily Loads are quantitative management tools which describe the amount of 

pollutant a water body may receive without causing violation of state water quality 

criteria or standards. 

Because of the broad scope of FDEP statewide assessments, water quality information 

for the Manatee River watershed contained in the biannual assessments should be 

carefully evaluated along with results from locally-initiated studies to assure that the 

best available data are considered for development of water quality management goals 

and strategies. 

Management and Storage of Surface Waters 

The SWFWMD has adopted Management and Storage of Surface Waters Rules 

(Chapters 40D-4, 40D-40 and 40D-45, F.A.C.) to regulate the construction and 

operation of surface water management systems. These rules establish criteria for the 

management of water quality discharged from storm water treatment systems. 

Water Use Permitting 

The SWFWMD is responsible for administering the Water Use Permitting Program 

outlined in Chapter 40D-2, F.A.C. Conditions placed on water use permits often 

include requirements for surface or ground water quality monitoring and compliance 

with specific water quality criteria. 

The Agricultural Ground and Surface Water Management Program (AGSWMP), a 

program coordinated by the SWFWMD and the United States Department of 

Agriculture National Resource Conservation Service (NRCS), provides a streamlined 

approach for agriculturists to comply with the SWFWMD’s water quality protection rules 


April 26, 2001 3-7 


when seeking or renewing water use permits. The program allows farmers to qualify for 

statutory exemption from surface water permitting requirements by implementing sitespecific 

best management plans developed by specialists from the NRCS. 

Tampa Bay National Estuary Program 

The Tampa Bay National Estuary Program, a consortium of the United States 

Environmental Protection Agency, the Florida Department of Environmental Protection, 

the Southwest Florida Water Management District, Hillsborough, Pinellas, and Manatee 

Counties, and the Cities of Tampa, St. Petersburg and Clearwater has developed a 

comprehensive plan (Tampa Bay National Estuary Program 1996) for the protection 

and restoration of Tampa Bay. In support of this task, the program has funded 

numerous investigations of the water quality of rivers flowing into the bay, and outlined 

specific goals and strategies for bay restoration. 

Among the principal issues identified in the comprehensive plan is the recent decline in 

seagrass coverage throughout the bay and its association with excessive nitrogen 

loading. The plan includes the recommendation that nitrogen loading to the bay should 

be limited to levels which occurred in 1992-1994 to promote recovery of seagrass 

populations. From 1992-1994, the Manatee River watershed accounted for about 13% 

of the total nitrogen loading to the bay (Coastal Environmental, Inc. 1996), so control of 

nitrogen loading from the watershed will play an integral part in meeting the nitrogen 

load reduction goals identified in the comprehensive plan. 

Surface Water Improvement and Management Program 

Restoration of the biological integrity of Tampa Bay is also an integral component of 

the District’s Tampa Bay Surface Water Improvement and Management (SWIM) plan 

(SWFWMD 1992). The SWIM program is actively involved in assuring that water 

quality goals outlined for the Manatee River watershed in the Tampa Bay SWIM plan 

and the TBNEP comprehensive plan are achieved. 

Shellfish-Harvesting Areas Classification 

The harvesting, processing and shipping of shellfish collected from Florida waters is 

regulated by the FDEP in accordance with Chapter 62-R7, F.A.C. Coastal waters are 

classified for shellfish harvesting based on levels of fecal coliform bacteria in proposed 

harvest areas, and meteorological, hydrographic and geographic characteristics that 

may affect the concentration of pollutants in the harvest areas. Six shellfish-harvesting 

classifications are currently recognized: Approved, Conditionally-Approved, Restricted, 

Conditionally-Restricted, Prohibited, and Unclassified. The FDEP conducts frequent 

monitoring of shellfish-harvesting areas, including those of the Manatee River 

watershed, and issues monthly reports listing areas where harvesting is prohibited. 

Local Zoning for Surface Water Protection 

The Manatee Board of Commissioners has adopted several zoning ordinances for the 

protection of water quantity and quality in Lake Manatee and the Bill Evers Reservoir. 

The Watershed Protection Overlay District Ordinance provides for water quality 


April 26, 2001 3-8 


protection in the Lake Manatee and the Bill Evers Reservoir watersheds by establishing 

specific guidelines for septic tank system installation, stormwater runoff, and mining 

activities. Additional protection for water resources in the county is provided by the 

Special Treatment Overlay District Zoning Ordinance which addresses permitting 

responsibilities regarding proposed industrial, mining or other earth-moving activities in 

sensitive areas. The county has also adopted specific Mining and Reclamation and 

Stormwater Management Ordinances for the protection of water quality in the 

watershed, and a landspreading ordinance which prohibits the landspreading of 

domestic wastewater residuals within the Lake Manatee and the Bill Evers Reservoir 

watersheds. Regulatory oversight of programs involved in implementation of these 

ordinance are the responsibility of the Manatee County Environmental Management 

and Planning and Public Works Departments. 

Non-Governmental Sources of Water Quality Data for the Manatee River 


Water quality data for various water bodies in the Manatee River watershed are 

collected by numerous non-governmental agencies in support of applications for 

approval of developments of regional impact or as requirements for water-use permits 

or development orders. Summaries of these data are typically available at county 

government offices. 

3.2 Introduction to Water Quality Issues of the Manatee River Watershed 


Water quality in the Manatee River watershed is generally good. However, several 

problems and issues concerning water quality of the watershed need to be addressed, 

including: violations of state water quality criteria in some surface waters; intrusion of 

saltwater into the surficial, intermediate and Upper Floridan aquifers underlying coastal 

areas; the need for additional water quality monitoring data and coordination of 

monitoring programs; the development of mechanisms for appropriate analyses of 

monitoring data; and the need for an ongoing effort for development and 

implementation of water quality improvement projects. 

3.2.2 Water Quality Problems 

Water quality problems in the Manatee River Watershed include: 

• High concentrations of the nutrients nitrogen and/or phosphorus; 

Nitrogen and phosphorus are essential nutrients required for growth of 

aquatic plants and algae. High concentrations of these nutrients may 

lead to excessive growth and water quality problems, including 

depressed oxygen levels, resulting from stagnation and decay of plant or 

algal organic matter, and taste, odor and toxicity concerns associated with 

compounds produced by blue-green algae (cyanobacteria). 


April 26, 2001 3-9 


State criteria require that “in no case shall nutrient concentrations of a 

body of water be altered so as to cause an imbalance in natural 

populations of aquatic flora or fauna” (Chapter 62-302, F.A.C) In 

addition, nitrate concentration must not exceed 10 mg/L (as nitrogen) in 

Class I waters. For its most recent assessment of statewide water quality, 

the FDEP (1996) used total phosphorus values of 0.24, 0.12 and 0.07 

mg/L as screening levels for the determination of impairment of 

designated use of the states streams (rivers), lakes and estuaries. 

• Low dissolved oxygen concentrations; 

The concentration of dissolved oxygen affects the types and rates of 

chemical reactions occurring in aquatic ecosystems, and strongly 

influences the abundance and distribution of aquatic organisms. Shortlived, 

acute depression of oxygen level may result in substantial mortality 

of aquatic animals (e.g. fish kills), while chronic depression may result in 

a limited-diversity community comprised of a few tolerant species. 

State criteria for Class I and III waters stipulate that dissolved oxygen 

concentration shall not be less than 5.0 mg/L. 

• High or low pH values; 

An indication of acidity, the hydrogen ion concentration, or pH influences 

the types and rates of chemical reactions occurring in a water body, and 

thus exerts control on the aquatic community. Most species are adapted 

to live within a limited range of pH values. So activities resulting in 

elevated or depressed pH values may cause significant mortality and 

shifts in community composition. 

State criteria require that pH “shall not vary more than one unit above or 

below natural background” and shall not be lowered to less than 6 

standard units or raised above 8.5 standard units. 

• High concentrations of dissolved copper and other metals; 

Trace quantities of many common metals are necessary for the metabolic 

requirements of aquatic organisms (e.g. copper, zinc), but may become 

toxic when present at levels exceeding metabolic needs. Others, not 

used by most organisms (e.g. mercury, lead), may also reach toxic levels. 

State criteria for some metals are specified by maximum allowable 

concentrations while criteria for others, including copper, are contingent 

upon the water hardness (as determined by calcium carbonate 

concentration) . 

• High densities of total and fecal coliform bacteria; 

The presence of fecal and total coliform bacteria provides an indication of 

contamination of a water body with feces from warm-blooded animals, and 


April 26, 2001 3-10 


thus provides a means for evaluating the potential for spread of 

waterborne infectious diseases. Sources of coliform bacteria include 

incompletely treated effluent from wastewater treatment plants, leaking 

septic tanks, and stormwater runoff. 

State water quality criteria for surface waters stipulate that numbers of 

fecal coliforms per 100-ml sample “shall not exceed a monthly average of 

200, nor exceed 400 in 10% of the samples, nor exceed 800 on any one 

day”. Monthly averages are based on at least 5 (Class I) or 10 (Class III) 

samples taken over a 30 day period. 

• High concentrations of total suspended solids; 

Introduction of high concentrations of total suspended solids (inorganic 

and organic particulate matter) into a water body often results in a 

reduction in oxygen content and water clarity, and an increase in toxic 

effects. Total suspended solids may have a high biological or chemical 

oxygen demand, and may further reduce oxygen levels by shading 

photosynthetically active plants and algae. Increased turbidity levels and 

sediment-smothering of substrates may also directly impact feeding and 

other behaviors of many animal species, and toxins associated with 

particulate matter can directly and indirectly affect all biota. 

For its most recent assessment of statewide water quality, the FDEP 

(1996) included a screening level of 12.5 mg/L total suspended solids as 

one factor for its evaluation of stream water quality. 

• High concentrations of total dissolved solids, chloride and sulfate in 

ground water; 

High concentrations of total dissolved solids (inorganic and organic 

dissolved matter), chlorides and sulfates can render ground water 

unsuitable for use as a potable and irrigation water supplies. Increased 

concentrations of these chemical constituents in the surficial, intermediate 

and Upper Floridan aquifer are frequently associated with intrusion of 

saltwater resulting from excessive ground water pumping. 

3.3 Review of Surface Water Quality Information and Issues 


Surface water quality of the Manatee River watershed is reviewed in this section. 

For this review, the Manatee River and Braden River sub-watersheds are subdivided 

into upper, lower and middle segments (Figure 3-1). Each watershed segment is 

described, and water quality information from recent assessments of the Florida 

Department of Environmental Protection (FDEP 1994a, 1996) and other significant 

historical and recently completed water-quality studies is reviewed. A brief review of 


April 26, 2001 3-11 


available information on water quality of small ponds and isolated or semi-isolated 

wetlands in the watershed follows the segment summaries. The section concludes with 

a discussion of point sources of pollution and constituent loading studies of the 

watershed. 

3.3.2 The Upper Manatee River 

The North Fork of the Manatee River originates in the northeast corner of Manatee 

County, at an elevation of about 130 feet above the National Geodetic Vertical Datum. 

Peacock Branch and an unnamed stream enter the North Fork prior to its confluence 

with the East Fork of the river about 8 miles downstream from the headwaters. Several 

tributaries, including another unnamed stream, Webb Branch, Little Fort Crawford 

Creek and Fort Crawford Creek enter the river before it flows into Lake Manatee 

Reservoir. For the purposes of this review, the river and its tributaries above Lake 

Manatee Reservoir (i.e., upstream from the Verna Bethany Road bridge) constitute the 

Upper Manatee River segment. 

Water quality in the Upper Manatee River is the best in the watershed according to the 

1996 Water-Quality Assessment for the State of Florida (FDEP 1996). No water 

quality violations were noted for the North Fork of the river, but an unnamed tributary of 

the North Fork is listed as only partially supporting designated use. Water quality in 

the East Fork of the Manatee River was not characterized in the assessment. Water 

quality is rated as “good” in the main stem of the river upstream from Lake Manatee, 

although phosphorus concentrations are high and mercury and iron concentrations 

exceeding state standards have been reported. An unnamed stream entering the river 

below the confluence of the North and East Forks is classified as only partially 

supporting its’ designated use. Webb Branch, Little Fort Crawford Creek and Fort 

Crawford Creek, the other tributaries entering the river above the reservoir were not 

evaluated in the FDEP report. Results from the 1994 Florida Department of 

Environmental Protection Non-point Source Assessment indicate that reaches of the 

Manatee River above Lake Manatee are “threatened”, which means they fully support 

their designated use, but may fail to do so in the coming years if management activities 

are not implemented (FDEP 1994a). Water quality in the two basins drained by 

unnamed streams was categorized as “fair” in the non-point source assessment, 

indicating that some, but not all of the surface waters of these watersheds support their 

designated use. No segments of the Upper Manatee River are included in the 303(d) 

list of impaired water bodies approved by the USEPA in 1998. 

Water quality data for the Upper Manatee River segment has typically been collected 

for the purpose of evaluating impacts of proposed and existing phosphate-mining 

activities on Lake Manatee. Limited sampling of sites in the East and North Forks of 

the Manatee River in the 1970s indicated that water quality in the upper Manatee River 

segment suffered from low dissolved oxygen, high iron and high nutrient concentrations 

(Swift Agricultural Chemicals, Inc. 1978). Sampling conducted in 1980 and 1982 

identified localized problems with levels of lead, mercury, and zinc (Gee and Jenson 


April 26, 2001 3-12 


Engineers-Architects-Planners, Inc. 1981, 1984). Low dissolved oxygen levels were 

also measured in 1996-1997 at sites in the East and North Forks of the Manatee River 


April 26, 2001 3-13 


Figure 3-1: Segmentation of the Manatee River Watershed for Discussion of 

Water Quality Issues 

Figure 3-1. Segmentation of the Manatee River watershed for 

discussion of water quality issues. 

Hillsborough County 

6 

3 

2 

1 

5 

4 


Sarasota County 

N 

0 5 10 15 20 Miles 

W 

E 

S 

1. Upper Manatee River Segment 

2. Middle Manatee River Segment 

3. Lower Manatee River Segment 

4. Upper Braden River Segment 

5. Middle Braden River Segment 

6. Lower Braden River Segment 


April 26, 2001 3-14 


where IMC Agrico Co. operates the Four Corners Mine (IMC Agrico Co. 1997). Results 

from the first two years (1995-1997) of a three-year study of the impacts of mining at 

the Four Corners mine indicate that with the exception of low dissolved oxygen levels, 

Class I water quality standards have not been exceeded during recent years at sites in 

the East and North Forks of the Manatee River (QST Environmental, Inc. 1998). 

3.3.3 The Middle Manatee River 

Lake Manatee Reservoir was created during 1965-1967 to provide drinking-water for 

the citizens of Manatee and Sarasota Counties by dredging the Manatee River 

floodplain and impounding the river about 24 miles upstream from Tampa Bay. When 

full, the reservoir covers approximately 1,800 acres and has a mean depth of 12.8 feet 

(Clarke 1995). Several streams discharge into the lake, including Fisher Branch, Little 

Deep Branch, Corbit Branch, Craig Branch, Poley Branch, Gilley Creek and Boggy 

Creek. These tributaries (which occur downstream of the Verna Bethany Road bridge) 

and the reservoir are collectively grouped as the Middle Manatee River segment. 

According to the recent state water-quality assessment (FDEP 1996), high nutrient 

concentrations in Lake Manatee Reservoir and low dissolved oxygen levels in some of 

the tributaries of the reservoir are the major water quality problems in the segment. 

Although nutrient levels are high in Lake Manatee, water quality in the reservoir is in 

compliance with Federal Clean Drinking Water and Florida Safe Drinking Water Act 

standards. Water quality is “good” for most sub-basins of the segment, although water 

quality in the Gilley Creek basin is rated “fair,” due to low dissolved oxygen levels. 

Lake Manatee, Gilley Creek, Poley Branch, Corbit Branch, and Fisher Branch are listed 

as “threatened” in the most recent Florida Department of Environmental Protection 

Non-point Source Assessment (FDEP 1994a). Gilly Creek is included in the 303(d) list 

of impaired water bodies approved by the USEPA in 1998, with dissolved oxygen, 

coliforms and nutrients listed as parameters of concern. 

Because Lake Manatee is a source of drinking-water, much attention has been focused 

on the quality of water in the reservoir. In the late 1970s the Tampa Bay Regional 

Planning Council recognized that Lake Manatee and other regional reservoirs were 

suffering from excessively high nutrient levels, and recommended a suite of pollution 

control strategies for protection of these resources (Tampa Bay Regional Planning 

Council 1977, 1982). Results from a 1982 monitoring program developed in responses 

to the Council reports indicated that Lake Manatee and its tributaries were generally in 

compliance with state water quality standards, although levels of dissolved oxygen, 

ammonia, and alkalinity commonly exceeded state limits (Gee and Jenson Engineers- 

Architects-Planners, Inc. 1981, 1984). Nutrient levels in the reservoir were high; mean 

total nitrogen was 1.5 mg/L and mean total phosphorus was 0.3 mg/L. Agricultural 

runoff was identified as a major contributor to nitrogen loading to the reservoir. An 

analysis of the Florida Trophic State Index (an index of eutrophication, see Huber et al. 

1982) values for Lake Manatee in the mid-1980's indicated that water quality in the 


April 26, 2001 3-15 


eservoir was degrading, and by 1986 the lake could be classified as eutrophic 

(Manatee County Public Works Department 1986). 

Increased awareness of nutrient-related problems in Lake Manatee prompted two major 

investigations of agricultural practices in the watershed. The first, a joint-effort between 

the United Stated Department of Agriculture Soil Conservation Service (currently 

known as the NRCS), the Manatee County Public Utilities Department, and the District 

involved the monitoring of nutrient concentrations in shallow groundwater beneath 

several citrus groves, and an evaluation of the effectiveness of various best 

management practices on reducing nutrient pollution (USDASCS 1992). The second, a 

NRCS initiative, evaluated nutrient levels and potential off-site loadings of nitrate and 

phosphate applied to vegetable crops and citrus groves (McNeal et al. 1995, Stanley et 

al. 1995). Results from these studies indicate that current citrus farming practices in 

the region can lead to persistent, elevated levels of nitrate in surficial ground water, 

and that movement off-site is on the order of several hundred feet per year. Farming 

practices associated with vegetable production are apparently more conducive for 

denitrification, and thus vegetable fields may not pose as serious a threat as citrus 

groves, in terms of nitrogen loading to Lake Manatee (McNeal et al. 1995). 

Contamination of surface waters with excess phosphorus may, however, be a problem 

at vegetable production sites during periods of heavy rainfall or if irrigation watermanagement 

systems are not well operated (Stanley et al. 1995). 

A recent, comprehensive review of water quality in Lake Manatee from 1983-1992 

provides a good summary of typical conditions in the reservoir (Clarke 1995, Clarke et 

al. 1997). For this period, water quality in the reservoir was characterized as “generally 

good”, although levels of dissolved oxygen, alkalinity, ammonia and copper frequently 

were in violation of state standards. Violations of the state standards for lead and 

turbidity also occurred, but were rare. Alkalinity problems in the reservoir may be 

attributed to the natural geology of the watershed. Elevated ammonia levels are 

presumed to be a consequence of pollution from agricultural runoff or biodegradation of 

nitrogenous organic compounds. Elevated copper levels have likely resulted from the 

permitted use of the algicide copper sulfate for the control of algal blooms in the 

reservoir. Nutrient levels during this period were high; mean total phosphorus was 0.3 

mg/L, total Kjeldahl nitrogen averaged 1.1 mg/l, and mean nitrate concentration was 0.2 

mg/L. The average nitrogen to phosphorus ratio was about six, indicating that Lake 

Manatee is a nitrogen-limited system, i.e., growth of algae in the reservoir is limited by 

the amount of available nitrogen. 

During late-spring and summer, metabolites produced by large populations of 

cyanobacteria (blue-green alga) may impart an unpleasant taste or odor to drinkingwater 

obtained from Lake Manatee. Taste and odor problems are mitigated using 

carbon adsorption during the drinking-water production process, but this processing 

step is expensive; costs to treat water withdrawn from the reservoir can exceed 

$14,000 per day (Clarke et al. 1997). These problems are more cost-effectively 

addressed by using copper sulfate to reduce cyanobacteria populations in the 

reservoir, an activity which the FDEP currently permits. Application of copper sulfate to 


April 26, 2001 3-16 


localized regions of Lake Manatee where blooms occur or are expected to occur has, 

however, contributed to the frequent violations of the state standard for copper. From 

1983-1992, the mean copper concentration in the reservoir was 44 Fg/L (Clarke 1995), 

a level eight times greater than the permissible concentration of 5.6 ug/L for Class I 

waters, determined using the mean hardness value of 41.9 mg/L of calcium carbonate 

for the period. Copper is toxic to many aquatic organisms, affecting development 

metabolism at high concentrations (reviewed by Leland and Kuwabara 1985, Crompton 

1997). 

3.3.4 The Lower Manatee River 

The river and the tributaries entering the river downstream from the Lake Manatee dam 

constitute the Lower Manatee River segment. Just below the dam, three small 

tributaries, Sand Branch, Rye Branch and Goddard Creek enter the meandering river. 

About 7.5 miles downstream, Mill Creek and a major tributary, Gamble Creek also join 

the river. Tributaries to Gamble Creek include Water Hole Creek, Tyre Creek and 

Harvey Prong. A portion of Gamble Creek is channelized, forming Fry Canal. 

Downstream from the mouths of Gamble and Mill Creeks the river widens and the 

channel becomes braided. A small tributary, Gates Creek enters the braided reach of 

the river which ends where Cypress Strand joins the river, about 10 miles from the 

Tampa Bay. Downstream, the Braden River and Wares Creek join the river from the 

south, and the river margin is marked by several small bayous and dredged canals. 

Much of the Lower Manatee River segment is tidally influenced. 

Water quality in the Manatee River below Lake Manatee is “good” according to the 

recent state water quality assessment (FDEP 1996), although high chlorophyll and low 

dissolved oxygen levels commonly occur in the estuary. A major fish kill occurred in 

the river near Bradenton during 1994-1995 and was attributed to low dissolved oxygen 

levels associated with an algal bloom. Water quality in Gamble Creek, Wares Creek 

and Mill Creek, is “poor”. Problems in Gamble Creek include low dissolved oxygen, 

high nutrients levels, and high counts of fecal coliform bacteria. Wares Creek and Mill 

Creek also have high bacteria levels. According to the 1994 non-point source 

assessment, Mill Creek, Cypress Strand, Gates Creek, and Gamble Creek are 

“threatened”, while Wares Creek and the Manatee River below the dam are listed as 

“fair” (FDEP 1994a). The Manatee River (near the Braden River) is included in the 

Florida Department of Environmental Protection’s preliminary list of estuarine and 

coastal waters affected by sediment contamination (FDEP 1996). Mercury, zinc and 

lead were listed as contaminants of concern for sediments of the region. Gamble 

Creek, Wares Creek and Mill Creek are included in the 303(d) list of impaired water 

bodies approved by the USEPA in 1998. 

A study of the effects of freshwater releases from Lake Manatee on water quality of the 

lower Manatee River in the early 1980's provides a good overview of historical 

conditions in the estuary (Manatee County Utilities Department and Camp, Dresser and 

McKee, Inc. 1984). Samples were collected along a gradient from principally 


April 26, 2001 3-17 


oligohaline conditions near the dam to mesohaline conditions at the mouth of the river. 

Total phosphorus concentrations generally declined with distance from the dam (range 

of site mean values = 0.1-0.4 mg/L) as did chlorophyll-a levels (range of mean values = 

7-10 ug/L). Nitrogen (total Kjeldahl nitrogen) concentration near the reservoir averaged 

1.5 mg/L and generally decreased downstream. High nitrogen levels were, however, 

measured at sites approximately two miles downstream from the Braden River inflow 

where effluent from two point sources (Tropicana Industries and the City of Bradenton 

Wastewater Treatment Plant) is discharged. Violations of state water quality standards 

occurred throughout all reaches of the lower Manatee River, but were most common in 

the highly urbanized region where the two point discharges and stormwater runoff from 

the City of Bradenton enter the river. Most violations were for low dissolved oxygen 

concentrations, with high pH, ammonia, fecal and total coliform bacteria levels 

accounting for the remainder. Additional summaries and sources of historical water 

quality in this segment of the Manatee River include Environmental Science and 

Engineering, Inc. (1977), Heyl (1982), DeGrove (1986), Flannery (1989), Drew (1990), 

and Wade-Trim (1987). 

Recent studies confirm that in some portions at least, the lower Manatee River is still 

plagued by localized oxygen deficits and high nutrient levels. From 1992-1996, 

dissolved oxygen concentrations in bottom waters at two sites in the river near the 

mouth of the Braden River were occasionally below criteria established for Class III 

waters, although surface waters were typically in compliance with the state standard 

(CCI Environmental Services, Inc. 1997a). Nutrient concentrations were measured at 

one of the sites; total nitrogen averaged 0.8 mg/L and mean total phosphorus 

concentration was 0.3 mg/L. High phosphorus levels (mean = 0.15 mg/L) were also 

measured at the mouth of the river during 1993 (Camp, Dresser and McKee, Inc. 1994). 

Mean chlorophyll-a concentration downstream of the mouth of the Braden River was 10 

ug/L from 1992-1996 and averaged 38 ug/L during periods of high flow. 

The quality of water in the Lower Manatee River segment may limit the use of this 

estuary as a shellfish harvesting site. A recent comprehensive survey of shellfishharvesting 

areas in Lower Tampa Bay, which relied heavily on measures of bacterial 

abundance, suggested that shellfish harvesting should be prohibited from the river’s 

mouth upstream to the U.S. Business 41 bridge (Florida Department of Natural 

Resources 1992). The temporary closure of shellfish-harvesting areas of the region 

due to blooms of toxic dinoflagellates, a phenomenon known as red-tide, is also 

common. From 1994-1996, shellfish harvesting in Lower Tampa Bay was prohibited for 

more than one hundred days each year as a result of red-tides (FDEP 1996). 

The installation of dams on the Manatee and Braden Rivers has impacted the flow 

regime of the lower Manatee River. Results from several studies illustrate the 

relationship between releases from the dam (flow) and salinity values at various points 

along the lower river segment (Manatee County Utilities Department and Camp, 

Dresser and McKee, Inc. 1984, Dames and Moore and Mote Marine Laboratory 1994, 

Camp, Dresser and McKee, Inc. 1995, Coastal Environmental, Inc. 1995). Modeling of 


April 26, 2001 3-18 


historical (pre-dam) flows and salinity values indicate that the impact of dam has been 

substantial near the dam, but has been minimal near the mouth of the river. 

Sediments in the lower Manatee River segment are generally uncontaminated with 

metals. Based on samples collected in 1996, concentrations of arsenic, cadmium, 

chromium, lead, nickel, and zinc in sediments from sites in the lower reach of the 

segment, where the river is no longer braided, do not exceed background levels 

(Environmental Protection Commission of Hillsborough County 1997). Concentrations 

of copper were typically not in excess of background levels, although elevated levels 

were detected at one site. Bioassay studies involving amphipod survival, sea urchin 

fertilization success and bacterial metabolism did not demonstrate any toxic effects 

associated with exposure to sediments or sediment extracts collected from the lower 

river segment (Long et al. 1995). 

3.3.5 The Upper Braden River 

The Braden River originates in the east-central Manatee County, at an elevation of 

about 75 feet above the National Geodetic Vertical Datum. Several tributaries, 

including Wolf Slough, Hickory Hammock, Cooper Creek and its’ tributary, Foley Creek, 

and Cedar Creek drain into the river above the Bill Evers Reservoir. For the purposes 

of this review, these tributaries and the Braden River upstream from the mouth of 

Rattlesnake Slough constitute the Upper Braden River segment. 

Water quality in the watershed above the Bill Evers Reservoir is “fair” to “good” 

according to the most recent Florida Department of Environmental Protection 

assessment of state water quality (FDEP 1996). Water quality problems in the main 

stem of the river and in Cedar Creek are associated with high nutrient concentrations, 

and levels of total suspended solids, dissolved oxygen, and total coliform bacteria in 

violation of state standards or FDEP screening criteria. Water quality in Hickory 

Hammock, Cooper Creek and Foley Creek is characterized as “good”. Results from the 

state-funded non-point source assessment indicate that the upper Braden River and its 

tributaries fully support their designated use, but may fail to do so in the coming years if 

management activities are not implemented (FDEP 1994a). Water quality violations 

have led to the inclusion of the Braden River segment above the Bill Evers Reservoir 

and Cedar Creek on the 303(d) list of impaired water bodies approved by the USEPA in 

1998. 

The quality of water in the segment from 1988-1992 is summarized in a recent report 

prepared by the Environmental Action Commission of Manatee County (1993). Water 

quality problems during this period included low dissolved oxygen concentrations, high 

nutrient and iron concentrations, and excessive levels of coliform bacteria. Oxygen 

deficit problems were most pronounced in Cedar Creek and in the main stem of the 

river downstream from Cooper Creek. High phosphorus concentrations were measured 

in Cedar Creek and in the Braden River near Wolf Slough. Total Kjeldahl nitrogen 

concentrations were usually

concentrations at several sites exceeded 3 mg/L. Peak concentrations of nitrate plus 

nitrite ranged up to 1-2 mg/L at some sites. Iron levels commonly exceed the state 

Class I standard of 0.3 mg/L at sites throughout the segment. Concentrations of fecal 

and total bacteria exceeded state standards at each of the sampled sites. Violations 

were particularly pronounced near the mouth of Hickory Hammock and in the Braden 

River below Wolf Slough. 

Additional water quality data for specific reaches of the river and its tributaries has 

been summarized in numerous other reports. For example, a recent study of water 

quality in the Bill Evers Reservoir and the lower Braden River for the period from 1992- 

1996 (CCI Environmental Services, Inc., 1997a) included sampling at a site near the 

interstate 75 bridge. Total nitrogen at the site averaged 0.7 mg/L, and total phosphorus 

was 0.3 mg/L. Levels of mercury and silver at the site were occasionally in violation of 

state standards. Limited sampling conducted in 1985 for an application for a 

development of regional impact identified levels of iron, cadmium, mercury, and zinc 

exceeding state standards in the upper Braden River, Wolf Slough and Hickory 

Hammock (SMR Development Corporation 1985). Earlier sampling of Cooper Creek 

for another application for approval of a development of regional impact identified 

levels of lead, iron and zinc in excess of state standards (Wilbur Boyd Corporation 

1984). Water quality problems in Long Swamp, which drains to Foley Creek, include 

low dissolved oxygen, high bacteria levels and concentrations of zinc in excess of state 

standards (Schroeder-Manatee, Inc. 1991). 

3.3.6 The Middle Braden River 

The Braden River was dammed in the late 1930s to develop a drinking-water supply for 

the City of Bradenton. The resulting impoundment, Ward Lake, was enlarged from 

about 167 acres to about 359 acres in 1985 and renamed the Bill Evers Reservoir. The 

reservoir and two tributaries, Rattlesnake Slough and Nonsense Creek constitute the 

Middle Braden River segment. 

Based on data from 1981-1989 for the Bill Evers Reservoir (Ward Lake) and from 

1990-1994 for Alligator Slough and Nonsense Creek, water quality in the Middle 

Braden River segment is characterized as “fair” in the most recent Florida Department 

of Environmental Protection assessment of water quality in the state (FDEP 1996). 

Water quality problems in Nonsense Creek include high total suspended solids and 

total coliform bacteria densities. High concentrations of total coliform bacteria and 

nutrients, in particular phosphorus, were identified as problems in the Bill Evers 

Reservoir and Rattlesnake Slough. Low oxygen concentrations are also common in 

Rattlesnake Slough. Water quality in the Bill Evers Reservoir is in compliance with the 

Federal Clean Drinking Water and Florida Safe Drinking Water Act standards, although 

the Bill Evers Reservoir (Ward Lake), Rattlesnake Slough and Nonsense Creek are 

listed as “threatened” in the most recent Florida Department of Environmental 

Protection Non-point Source Assessment (FDEP 1994a). Rattlesnake Slough and 


April 26, 2001 3-20 


Nonsense Creek are also included in the 303(d) list of impaired water bodies approved 

by the USEPA in 1998. 

Because the middle Braden River has been a major source of drinking-water for much 

of this century, a considerable amount of water quality data has been collected for the 

segment. For example, Smith and Gillespie Engineers, Inc. (1971) present alkalinity 

and hardness data collected by the City of Bradenton Water Department from 1943- 

1970 and bacteria abundance data collected by the Manatee County Health 

Department from 1960-1970. Additional reports containing summaries of historical 

water quality data for the Bill Evers Reservoir include Camp, Dresser and McKee 

(1985) and Smith and Gillespie Engineers, Inc. (1987). 

More recently, water quality in the segment has been studied to evaluate impacts of 

existing and future land use activities on water quality in the reservoir (Environmental 

Action Commission of Manatee County 1993), and for compliance with a water use 

permit issued by the District to the City of Bradenton (CCI Environmental Services, Inc. 

1997a). Water quality problems in the segment from 1988-1996 included low 

dissolved oxygen concentrations in Alligator Slough and in the bottom waters of the Bill 

Evers Reservoir, high total phosphorus and copper concentrations in the reservoir, high 

iron concentrations in Alligator Slough and Nonsense Creek, occasional violations of 

state criteria for mercury and silver in the reservoir, and frequent violations of fecal and 

total coliform bacteria standards throughout the segment. Water hardness, pH, 

conductivity and levels of chlorophyll-a, total dissolved solids, sulfate, copper and 

dissolved oxygen are highest during low flow conditions, however statistical 

relationships between these parameters and flow are weak. Annual Trophic State 

Index values for the Bill Evers Reservoir from 1988-1992 are indicative of mesotrophic 

conditions (Environmental Action Commission of Manatee County 1993). However, 

examination of seasonal trophic index values indicate that the reservoir shifts from 

oligotrophic conditions in winter to eutrophic conditions during summer months. In 

addition, it is likely that the use of copper sulfate for the control of cyanobacterial 

populations in the reservoir has the effect of lowering the annual Trophic State Index 

values from the eutrophic range to the mesotrophic range. 

Values of most water quality parameters in the Bill Evers Reservoir during 1992-1996 

were similar to those reported for 1988-1992, although changes in some indicate that 

the quality of water in the reservoir may be worsening. Mean total phosphorus level in 

the reservoir from 1992-1996 (CCI Environmental Service, Inc. 1997a), was similar to 

that during the previous four years (Environmental Action Commission of Manatee 

County 1993), averaging about 0.3 mg/L for both periods. Mean total nitrogen level in 

the reservoir increased from 0.6 mg/L during 1988-1992 (Environmental Action 

Commission of Manatee County 1993) to 0.8 mg/L from 1992-1996 (CCI Environmental 

Inc. 1997a). Chlorophyll-a levels have also increased in recent years, from a mean of 2 

ug/L for 1998-1992 to 9-10 ug/L for 1992-1996. 


April 26, 2001 3-21 


The City of Bradenton applies copper sulfate to the Bill Evers Reservoir when 

necessary for control of cyanobacteria populations in order to minimize associated 

taste and odor problems in drinking-water obtained from the reservoir. This practice, 

which is permitted by the FDEP, frequently results in dissolved copper concentrations 

in excess of Class I criteria. For example, mean copper concentration in the reservoir 

was 13 ug/L during 1988-1992 (Environmental Action Commission of Manatee County 

1993) and was 50 ug/L from 1992-1996, with peak values approaching 400 ug/L (CCI 

Environmental Services, Inc. 1997a). Based on a mean hardness value for the 

reservoir from 1992-1996 (169 mg/L CaCO 3 ), copper levels in the reservoir should not 

have exceeded 18.5 ug/L according to state criteria for Class I waters. 

3.3.7 The Lower Braden River 

This segment consists of the Braden River and the tributaries entering the river below 

the Bill Evers Reservoir dam. The meandering river is joined by Gap Creek and 

Williams Creek about 1.2 miles below the dam. Downstream, Jeff’s Cowpen Creek and 

Sugarhouse Creek join the river before its flows into the Manatee River. Sugarhouse 

Creek and its’ tributary Glenn Creek are freshwater systems; the remainder of the 

segment is typically estuarine. 

Based on data from 1990-1995, water quality data for the lower Braden River near 

Ellwood Park was is characterized as “fair” in the most recent Florida Department of 

Environmental Protection assessment of state water quality (FDEP 1996). Historical 

(1980-1987) data for Gap Creek, Williams Creek and the Braden River at Jeff’s 

Cowpen Slough indicate “poor” conditions, with high levels of total and fecal coliform 

bacteria and high concentrations of phosphorus commonly reported. According to the 

FDEP report, the lower Braden River and Sugarhouse Creek fully support their 

designated use as a Class II water bodies, but Williams Creek and Gap Creek do not. 

Both creeks are included in the 303(d) list of impaired water bodies approved by the 

USEPA in 1998. The lower Braden River and its tributaries are listed as “threatened” in 

the Florida Department of Environmental Protection Non-point Source Assessment 

(FDEP 1994a). 

In the mid-1980s, the Tampa Bay Regional Planning Council (1986) noted that 

information on the quality of water in the lower Braden River segment was meager, but 

problems with high nutrient levels, low dissolved oxygen concentrations, and 

excessively high levels of total and fecal coliform bacteria were evident. The report 

concluded that further degradation of the segment was likely to occur. 

A recent study indicates that oxygen deficits and high nutrient levels are still a problem 

in the segment (CCI Environmental Services, Inc. 1997a). From 1992-1996, dissolved 

oxygen levels below the state criteria established for Class II water were frequently 

measured in bottom waters of the estuary at sites near the dam during low flow periods. 

Oxygen levels in surface waters were typically in compliance with the state standard. 

Mean total nitrogen concentration for three sites in the river and one site in the 


April 26, 2001 3-22 


Manatee River just downstream from the mouth of the Braden River was 0.9 mg/L. 

Total phosphorus concentrations were also high, averaging 0.3 mg/L, as were 

chlorophyll-a levels, which averaged 11 ug/L. Average salinity ranged from 5 parts per 

thousand below the dam to 18 parts per thousand at the confluence with the Manatee 

River, and was significantly correlated with freshwater flow from the reservoir. 

Information on concentrations of metals in sediments of the lower Braden River is 

limited. Sampling at two sites near the mouth of the river was conducted in 1996, and 

levels of arsenic, cadmium, chromium, copper, lead, nickel, and zinc were not found to 

exceed background levels (Environmental Protection Commission of Hillsborough 

County 1997). 

3.3.8 Lakes and Isolated and Semi-Isolated Freshwater Wetlands 

Small ponds and isolated or semi-isolated wetlands are common in the Manatee River 

watershed. None of these systems are presently included in the Southwest Florida 

Water Management District Ambient Monitoring Program or any other governmental 

monitoring program, so little information is available on their water quality. 

Water quality data for a few of these systems has been collected to fulfill requirements 

for development of regional impact applications. Two ponds adjacent to Wolf Slough in 

the upper Braden River segment were sampled on a single date in 1985 (SMR 

Development Corporation 1985). Dissolved oxygen concentration was low in one of 

the ponds, while the other exhibited good water quality except for high coliform bacteria 

levels. More extensive sampling (six dates in spring) of another pond and of Long 

Swamp, which drains to Foley Creek in the upper Braden River segment was 

conducted in 1991 (Schroeder-Manatee, Inc. 1991). Nutrient levels in the pond were 

high; total nitrogen averaged 1.0 mg/L and total phosphorus was 0.1 mg/L. In the 

swamp, dissolved oxygen levels and concentrations of zinc (based on one sampling 

date) were in violation of state standards. Total coliform bacteria levels in both habitats 

exceeded state standards. Water quality samples collected from two marshes in the 

watershed (Tara Development, Ltd. 1980) suggests that these habitats may be 

characterized as acidic, softwater systems with high nutrient levels (total phosphorus = 

1.5mg/L, total nitrogen = 3.0 mg/L). Concentrations of zinc and abundances of total 

coliform bacteria in the marshes exceeded state standards. 

3.3.9 Point Source Pollution 

Point source discharges to surface waters are permitted by the United States 

Environmental Protection Agency (USEPA) National Pollutant Discharge Elimination 

System (NPDES). In Florida, NPDES permitting is administered by the Florida 

Department of Environmental Protection (FDEP). 

There are currently four major NPDES-permitted discharges in the watershed. Effluent 

from the City of Bradenton domestic wastewater treatment facility, Tropicana Industries 


April 26, 2001 3-23 


industrial waste treatment facility, and mixed cooling water and storm water from the SI 

Palmetto facility is discharged into the Manatee River. SMR Aggregates discharges 

effluent from a wastewater treatment plant into the Braden River. State criteria for 

dissolved oxygen have occasionally been exceeded in recent years at the SI Palmetto 

and SMR Aggregates facilities, and high metal levels and low biological diversity have 

been documented at the Tropicanna Industries facility. 

3.3.10 Constituent Loading Studies 

In support of the Tampa Bay National Estuary Program, estimates of annual loadings of 

nutrients and suspended solids to Tampa Bay from the Manatee River watershed have 

recently been developed (Coastal Environmental, Inc. 1994). These estimates were 

developed using a hydrologic model, estimates of point and non-point contributions to 

the total loads, and estimates of loads from atmospheric deposition and ground water 

discharges. Non-point sources accounted for the bulk of the total phosphorus and total 

nitrogen loadings to the bay from the watershed for the years 1985 through 1991 

(Table 3-1). Loading of total suspended solids during 1985-1991 was more evenly 

distributed among point and non-point sources, although point-sources accounted for 

the greater load (Table 3-1). Nitrogen loading for 1992-1994 has recently been 

estimated at 503 tons/year (Coastal Environmental, Inc. 1996), a value similar to the 

average for the previous six year period. 

Predictions of future land use in the Manatee River watershed indicate that the 

acreage of urban lands in the watershed may triple by the year 2010 (see Chapter 2 of 

this report). Nutrient loading estimates based on projected land use patterns (Coastal 

Environmental, Inc., 1994) indicate that annual loads of total nitrogen and phosphorus 

from the Manatee River watershed may nearly double by the year 2010, and 

suspended solids loads may increase by one-third (Table 3-1). 

The contributions of nutrients from individual on-site wastewater treatment systems and 

wastewater residual land application sites in the Manatee River watershed have been 

evaluated in another recent study of nutrient loadings to Tampa Bay (Ayers Associates 

1995). The estimated nitrogen load from on-site wastewater treatment systems 

represents about 3% of the mean annual nitrogen load estimate for 1985-1991 (see 

Table 3-1), and the phosphorus load from these systems is estimated at 15% of the 

total phosphorus load. Nitrogen loads from land spreading of wastewater residuals 

was approximately 15% of the total loads for 1985-1991. The phosphorus loading from 

residuals sites was estimated at 285 tons/yr, a value two times greater than the 

estimated mean total phosphorus loading from the Manatee River watershed during 

1985-1991. This discrepancy indicates that the loading estimates from the residual 

application sites may not accurately reflect levels of phosphorus entering the waters of 

the region. 


April 26, 2001 3-24 


In addition to the models developed to evaluate loadings to Tampa Bay, several efforts 

to estimate loadings to specific reaches in the Manatee River watershed have been 

completed during the past twenty years. 

Table 3-1: 

Mean total Nitrogen, phosphorus and suspended solids loadings to 

Tampa Bay from the Manatee River watershed for 1985-1991 and 

projected loading for the year 2010. Percentages of loadings from 

point sources, non-point sources and atmospheric deposition for 

1985-1991 are also shown. Loading values are from Coastal 

Environmental, Inc. (1994) 

Period 

Loadings in Tons/Year* 

Total Nitrogen 

Total 

Phosphorus 

Total Suspended 

Solids 

1985- 

1991 

488 

Non-Point 

72% 

132 

Non-Point 

70% 

7,398 

Non-Point 

41% 

Point 

19% 

Point 

3% 

Point 

59% 

Atmospheric 

Deposition 

9% 

Atmospheric 

Deposition 

27% 

Atmospheric 

Deposition 

0% 

circa 

915 250 10,000 

2010 

* Estimates are loadings for a segment of the Tampa Bay watershed that consists primarily of 

the Manatee River watershed. 

Loadings of total nitrogen and phosphorus to the Bill Evers Reservoir in the mid-1980’s 

were estimated to be 83.1 and 15 tons/year, respectively, based on land-use patterns 

determined from 1984 aerial photographs, and land-use specific loading factors (Camp, 

Dresser and McKee 1985). Under various land use scenarios nutrient loadings were 

predicted to double and metal loadings increased 5-35 fold, if management practices 

were not instituted to reduce nutrient pollution. Recent loading estimates indicate that 

loading has not increased appreciably. Using 1990 land-use information, Camp, 

Dresser and McKee, Inc. (1996) estimate current annual loadings to the reservoir of 79 

tons total nitrogen and 25 tons total phosphorus. Blanchard (1997) estimates that from 

1990-1994, nitrogen loadings to the reservoir averaged 78 tons/yr and phosphorus 

loadings averaged 20 tons/yr. No significant changes in annual nitrogen loading were 

detected for the four-year period, although phosphorus loads showed a decline of 

about 0.09 g/acre/day per year. 


April 26, 2001 3-25 


Nutrient loading estimates for Lake Manatee are somewhat greater than those reported 

for the Bill Evers Reservoir. Camp, Dresser and McKee, Inc. (1996) report that 

nitrogen and phosphorus loads to the reservoir average 149 and 57 tons annually. 

Blanchard (1997) estimates that nitrogen loading to the reservoir averaged 90 tons/yr 

for the period from 1990-1993, and noted that total nitrogen loads to Lake Manatee 

were increasing by about 0.4g/acre/day per year. 

3.4 Review of Ground Water Quality Information and Issues 


The aquifer systems underlying the Manatee River watershed are important sources of 

potable and non-potable water for the residents of Manatee and Sarasota Counties. 

Increased demands on these resources have led to severe changes in the 

potentiometric surface and quality of water in these systems. Efforts to maintain and 

improve surface and ground water quality of the region will support the continued use 

of these resources. 

This review of ground water quality information for the Manatee River watershed 

includes summaries of water quality in the surficial, intermediate and Floridan (Upper 

Floridan) aquifer systems. Each summary consists of a brief description of the aquifer 

system and the quality of ground water found in the aquifer. The storage of treated 

surface water in the Upper Floridan aquifer and the potential for contamination of 

ground-water in each of the aquifers is then briefly discussed. 

3.4.2 The Surficial Aquifer 

The surficial aquifer underlying the Manatee River watershed consists of Holocene and 

Pleistocene deposits of sand, gravel, shells, and limestone that vary in consistency and 

depth in an east-west gradient across the watershed (Southeastern Geological Society 

1986, SWFWMD 1988). In the eastern portion of the Manatee County, these deposits 

range in thickness from 10-90 feet; in the western portion of the county, the deposits 

range in thickness from 1-20 feet. The depth to the water table ranges from zero feet 

near the coast to about ten feet in eastern Manatee County. 

Water quality in the surficial aquifer varies within the watershed. In the eastern portion 

of the Manatee County, concentrations of dissolved solids, chloride and sulfate are low 

and the water is acidic (SWFWMD 1988). Near the coast, dissolved mineral 

concentrations are higher due to salt water intrusion; total dissolved solids often 

exceed 200 mg/L, chlorides often exceed 50 mg/L and sulfate concentrations are 

generally less than 20 mg/L. Nitrate concentrations in the surficial aquifer of the region 

are greater than in the intermediate and Upper Floridan aquifers (SWFWMD 1990). 

This is likely the result of the application of fertilizers, and contamination from human 

and animal wastes. The extensive use of ground water from the Floridan aquifer for 


April 26, 2001 3-26 


irrigation of agricultural lands also has the potential to alter the mineral content of 

ground-water in the surficial aquifer. 

3.4.3 The Intermediate Aquifer 

The intermediate aquifer system of the Manatee River watershed area consists of 

Pleistocene and Pliocene deposits of sandy clay, clay, marl, sand, gravel, shell and 

limestone lying between the surficial and Floridan aquifer systems (Southeastern 

Geological Society 1986). The sand and shell layers are typically less than ten feet 

thick; the limestone beds range from about 200-400 feet thick in a north-south gradient 

across the county (Duerr et al. 1988) The top of this aquifer system is near sea level 

throughout much of the region. 

Water quality in the intermediate aquifer varies across the Manatee River watershed. 

In the northern and eastern portions of the Manatee County, concentrations of total 

dissolved solids range from 200 to 400 mg/L, concentrations of chlorides are typically 

less than 50 mg/L and sulfates average less than 20 mg/L. In the southeastern and 

coastal regions of the county, concentrations of dissolved solids range from about 500- 

1,000 mg/L, concentrations of chlorides are generally less than 250 mg/L (except along 

the coast), and concentrations of sulfates range from about 100-500 mg/L. Fluoride 

concentrations are variable, ranging from less than 0.5 to 3.0 mg/L 

3.4.4 The Floridan Aquifer (Upper Floridan Aquifer) 

The Floridan aquifer system consists of limestones and dolomites that formed prior to 

the Miocene age (Miller 1986). In the Manatee River watershed region, the aquifer 

consists of two hydrologic units, the Upper and Lower Floridan aquifers, which are 

separated by a middle confining unit. The Lower Floridan aquifer contains highly 

mineralized water, so only the Upper Floridan aquifer will be discussed here. The 

Upper Floridan aquifer, which includes the Suwannee Limestone, Ocala Limestone and 

Avon Park Formation, is the most productive aquifer of the region, although the high 

mineral content of ground water from the aquifer limits use of this resource in some 

regions of the Manatee River watershed. The Upper Floridan aquifer varies in 

thickness from about 1,300 in northern Manatee County to 1,600 feet in the southern 

part of the county, and is well confined (SWFWMD 1988). 

The Upper Floridan aquifer is the primary source of water for agricultural use in the 

Manatee River watershed and also provides water for industrial use and 

supplementation of the supply of the potable water supply. Water quality in the Upper 

Floridan varies laterally within Manatee County, and becomes increasingly mineralized 

with depth (SWFWMD 1988). Concentrations of dissolved solids range from about 300 

to over 2,500 mg/L. Chloride concentrations in the eastern part of the county are 

generally less than 250 mg/L. Near the coast, concentrations range up to 18,500 mg/L 

(SWFWMD 1995). Sulfate concentrations are also high, typically ranging from less 


April 26, 2001 3-27 


than 5 mg/l to about 30,000 mg/L (SWFWMD 1988, 1995). Fluoride concentrations 

range from 0.5 to more than 3.0 mg/L (SWFWMD 1988). 

The potentiometric surface of the Upper Floridan aquifer has declined by as much as 

50 feet in Manatee County during the past fifty years (SWFWMD 1993). Declines in 

surface water levels and ground-water quantity and quality prompted the Southwest 

Florida Water Management District to declare in 1992 that the southern half of the 

District, which includes the Manatee River watershed, be identified as the Southern 

Water Use Caution Area (SWUCA). This designation included a prohibition on the 

issuance of new water-use permits in the Most Impacted Area of the SWUCA, a region 

which contains much of the Manatee River watershed. Limiting new-water-use permits, 

along with implementation of water conservation measures and development of 

alternative water sources is expected to prevent further lowering of the potentiometric 

surface of the Upper Floridan aquifer and reduce saltwater intrusion into the aquifer. 

3.4.5 Aquifer Storage and Recovery 

The storage of treated surface water from the Manatee River watershed in the Upper 

Floridan aquifer has been promoted as a partial solution to the water supply problem of 

the region. This technology, known as aquifer storage and recovery (ASR) involves the 

injection of treated water into the aquifer during periods when treatment capability 

exceeds the demand for potable water. The water is subsequently recovered from the 

aquifer when demand exceeds treatment capability. 

In 1983 a potable water ASR system was installed at the Lake Manatee Water 

Treatment Plant (CH2M Hill 1984). Concern over the quality of water recovered from 

the system initially limited implementation of this technology (Camp, Dresser and 

McKee, Inc. 1984). The technology has, however, proven to be suitable for use in the 

watershed; the system at Lake Manatee has been used intermittently by Manatee 

County for supplemental water storage during the past sixteen years. Manatee County 

has also recently proposed to expand the system by adding four ASR wells to the 

existing system of two wells (Montgomery Watson 1997). Manatee County and the 

District have also initiated an ASR project involving injection of reclaimed water at the 

Manatee County Southwest Regional Wastewater Treatment Facility, and the City of 

Bradenton has proposed the installation of two ASR systems in the Braden River 

watershed. 

3.4.6 Areas Susceptible to Ground Water Contamination 

The potential for contamination of groundwater in aquifers of the Manatee River 

watershed has been evaluated using physical information on the hydrogeologic setting 

of the region and chemical/isotopic information on water in the aquifers. Both 

approaches indicate that the potential for contamination of the Upper Floridan aquifer is 

low to very low in the Manatee River watershed (SWFWMD 1988, Swancar and 

Hutchinson 1992). The thickness of the intermediate aquifer system in the region, and 


April 26, 2001 3-28 


its relatively low permeability function as a barrier to downward movement of 

contaminants. Analyses based on the hydrogeologic setting indicate that the 

susceptibility of the intermediate aquifer system of Manatee County to contamination 

from surface sources is also low (SWFWMD 1988). However, the potential for 

contamination of the intermediate aquifer with ground water from the Upper Floridan 

aquifer exists in western Manatee County as a result of the high potentiometric surface 

of the Upper Floridan aquifer and from improperly cased wells (Metz and Brendle 

1996). Lateral intrusion of salt water into the intermediate aquifer system is also a 

problem in coastal areas of Manatee County. The surficial aquifer of the region is 

highly susceptible to ground-water contamination, due to the lack of confinement and 

non-artesian properties of the aquifer (SWFWMD 1988). 

3.5 Water Quality Issues/Problems, Strategies and Action Plans 


In this section, important water quality issues or problems identified in the review of 

surface and ground water quality information and issues (Sections 3.3 and 3.4) are 

grouped under five major headings: Nutrient Pollution, Toxicant Pollution, Pathogens 

and Public Health Impacts, Flow-related Water Quality Problems, and Data Gaps and 

Monitoring Needs. A brief review of pertinent background information is provided for 

each issue/problem, and action plans, consisting of recommended actions for 

implementing each strategy are then outlined. Each action is explored with regard to 

the party or parties responsible for the action, the costs associated with the action, and 

the time-frame for completion of the action. 

3.5.2 Nutrient Pollution 

Nutrient Pollution Issue #1: Excessive nutrient loading to Lake Manatee and the 

Bill Evers Reservoir promotes blooms of cyanobacteria that cause taste and odor 

problems in drinking-water obtained from the reservoirs. 

Background: Water quality is “good” in Lake Manatee and “fair” in the Bill Evers 

Reservoir, according to the recent Florida Department of Environmental Protection 

assessment of state water quality (FDEP 1996). Some degradation is the result of high 

nutrient concentrations in both systems. From 1983-1992, mean total phosphorus in 

Lake Manatee was 0.3 mg/L, total Kjeldahl nitrogen averaged 1.1 mg/L, mean nitrate 

concentration was 0.2 mg/L, and the concentration of ammonia nitrogen frequently 

exceeded the state criteria for Class I waters (Clarke 1995). Total phosphorus 

concentration in the Bill Evers Reservoir has not changed appreciably from 1988 

through 1996, averaging about 0.3 mg/L (Environmental Action Commission of 

Manatee County 1993, CCI Environmental Services, Inc. 1997a). From 1988-1992, 

total nitrogen concentration in the Bill Evers Reservoir was 0.6 mg/L (Environmental 

Action Commission of Manatee County 1993). In recent years (1992-1996), the 

concentration has averaged 0.8 mg/L (CCI Environmental Services, Inc. 1997a). 


April 26, 2001 3-29 


The high nutrient levels in the reservoirs promote the development of large populations 

of cyanobacteria. Chemicals produced by these cyanobacteria may impart unpleasant 

tastes and odors to drinking-water withdrawn from the reservoirs. Solutions to the 

taste/odor problem include the use of activated carbon to remove tastes and odors 

during the drinking-water production process and application of the algicide copper 

sulfate directly to the reservoirs to inhibit growth of cyanobacteria. Both approaches 

have negative consequences. The use of activated carbon can add substantial cost to 

the production of drinking-water, and the use of copper sulfate often results in violation 

of the state criteria for copper concentrations in potable water supplies. 

Recent modeling studies provide an indication of the magnitude of nutrient loads to 

Lake Manatee and the Bill Evers Reservoir and also offer benchmarks for setting 

nutrient pollution load reduction goals. Camp, Dresser and McKee, Inc. (1996) 

estimate that total nitrogen loading to the Lake Manatee is about 149 tons/yr and total 

phosphorus loading is about 57 tons/yr. Blanchard (1997) estimates mean annual 

nitrogen loading to the Lake Manatee for the period from 1990-1993 was 90 tons/yr and 

indicated that loadings increased significantly during the thee year period. Based on 

land use pattern data for 1990, Camp, Dresser and McKee, Inc. (1996) estimate total 

nitrogen loading to the Bill Evers Reservoir at approximately 79 tons/yr and total 

phosphorus loading at 25 tons/yr. Blanchard (1997) estimates nitrogen loading to the 

Bill Evers Reservoir averaged 78 tons/yr from 1990-1994, while total phosphorus 

loading averaged 20 tons/yr. 

Strategy: Evaluate nutrient loadings to Lake Manatee and the Bill Evers Reservoir and 

develop and implement a plan to ensure that nitrogen and phosphorus loadings from 

their watersheds do not exceed current levels, or are reduced to specified levels. 

Actions: 

1. Promote the collection, integration and analyses of water quality data for the 

upper and middle segments of the Manatee and Braden Rivers. 

Responsible Parties: Manatee County, City of Bradenton, United States 

Geological Survey, Florida Department of Environmental Protection, Southwest 

Florida Water Management District. 

Cost: $0 (Included in existing programs and program proposed under Data Gaps 

and Monitoring Needs Issue #1). 

Time-frame: Ongoing. 

2. Review current nutrient loading models to determine appropriateness of model 

assumptions, verify model predictions, and identify model or data deficiencies. 

Develop a new model or refine existing model and collect additional data for 

model input, if necessary. Use newly-developed or refined nutrient loading 

model to estimate current nutrient loadings to Lake Manatee and the Bill Evers 

Reservoir and estimate benchmark historical loadings (circa 1930-1940) for 

development of pollutant load reduction goals. 


April 26, 2001 3-30 


Responsible Parties: Manatee County, City of Bradenton, Southwest Florida 

Water Management District. 

Cost: $50,000. 

Time-frame: Two years. 

3. Conduct an empirical study of nitrogen loading from citrus groves to the surficial 

aquifer and Lake Manatee and the Bill Evers Reservoir within the Manatee River 

watershed. 

Responsible Parties: Southwest Florida Water Management District, National 

Resource Conservation Service, United States Geological Survey, Manatee 

County, City of Bradenton. 

Cost: $100,000. 

Time-Frame: Three years. 

4. Develop and implement plans for achieving pollutant load reduction goals. 

Specific guidance for this task is available in the Tampa Bay National Estuary 

Program comprehensive plan (Tampa Bay National Estuary Program 1996) and 

Coastal Environmental, Inc. (1997). Responsible Parties: Manatee County, City 

of Bradenton, Southwest Florida Water Management District. 

Cost: Unknown. 

Time-Frame: Ongoing. 

Nutrient Pollution Issue #2: High nitrogen loads from the Manatee River 

watershed have contributed to the degradation of seagrass communities in 

Tampa Bay. 

Background: Nitrogen loading has significantly harmed the ecological integrity of 

Tampa Bay. By 1982, over half of the area of Tampa Bay that was covered in 

seagrasses in 1950 no longer supported this valuable community type. The Tampa 

Bay National Estuary Program (1996) determined that excessive nitrogen levels in 

Tampa Bay have contributed to seagrass decline by favoring the growth of 

phytoplankton. In 1996, the Tampa Bay National Estuary Program adopted a five-year 

management plan to cap nitrogen loading to the bay at levels existing in 1992-1994. It 

is expected that seagrass communities will become established on over 29,600 ha as a 

result of compliance with this management goal. 

From 1992-1994, mean annual nitrogen loading for the segment of the bay watershed 

that contains the Manatee River watershed was 457,000 kg/yr (Coastal Environmental, 

Inc. 1996). Loading from this segment accounted for 13% of the total nitrogen loadings 

to the bay Control of nitrogen loading to the bay from the Manatee River watershed will 

therefore play an integral part in meeting the nitrogen load reduction goals identified in 

the Tampa Bay National Estuary Program comprehensive plan. 

Strategy: Develop and implement a plan to ensure that nitrogen loading from the 

Manatee River watershed is unchanged, or reduced to a level that promotes the 


April 26, 2001 3-31 


ecovery of seagrass communities in Tampa Bay as outlined in Charting the Course: 

The Comprehensive Conservation and Management Plan for Tampa Bay (Tampa Bay 

National Estuary Program 1996). 

Actions: 

1. Support the re-evaluation of the Tampa Bay National Estuary Program’s nutrient 

loading model (Coastal Environmental, Inc. 1994, 1996) for the Manatee River 

watershed. 

Responsible Parties: Tampa Bay National Estuary Program. 

Cost: $0 


2. Implement nitrogen load reduction actions identified in the Tampa Bay National 

Estuary Program (1996) comprehensive plan and updated load reduction 

recommendations. 

Responsible Parties: Florida Department of Environmental Protection, 

Southwest Florida Water Management District, Manatee County, Sarasota 

County, City of Bradenton, City of Palmetto. 



3.5.3 Toxicant Pollution 

Toxicant Pollution Issue #1: Concentrations of dissolved copper in Lake Manatee 

and the Bill Evers Reservoir frequently exceed state Standards for Class I waters. 

Background: Copper is essential for the functioning of many enzyme systems, but is 

acutely toxic to many aquatic organisms at concentrations in excess of metabolic 

requirements. Sources of copper contamination in aquatic habitats include combustion 

of fossil fuels, wastewater treatment plants and the use of copper sulfate for the control 

of nuisance algae. Contaminated runoff from roads in the Lake Manatee and the Bill 

Evers Reservoir watersheds is a probable source of copper loadings to the reservoirs. 

However, the bulk of copper introduced into these systems is likely derived from the 

permitted application of copper sulfate directly to the reservoirs by the City of 

Bradenton and the Manatee County Public Works Department. 

Copper concentrations in Lake Manatee and the Bill Evers Reservoir frequently exceed 

state standards for Class I waters. From 1983-1992, the mean copper concentration in 

Lake Manatee was 44 ug/L, a level eight times greater than the current permissible 

concentration of 5.6 ug/L for this Class I water body, based on the mean hardness 

value for the period. In the Bill Evers Reservoir, copper concentrations averaged 50 

ug/L from 1992-1996 (CCI Environmental Services, Inc. 1997a). Based on current 

state criteria for surface water classification and the mean hardness value for this 

period, concentrations of copper should not have exceeded 18.5 ug/L. 


April 26, 2001 3-32 


Information on the accumulation of copper in sediments of the reservoirs and in the 

sediments of the downstream river segments is limited or not widely available. 

Because copper is toxic to cyanobacteria, algae and other aquatic taxa, including 

fishes and invertebrates, the accumulation of copper in the sediments of Lake Manatee 

and the Bill Evers Reservoir and the transport of this metal to downstream reaches of 

the Manatee and Braden Rivers poses a potential environmental hazard. Sampling 

should be initiated to determine the concentration and distribution of copper in the 

sediments of Lake Manatee and the Bill Evers Reservoir and in segments of the 

Manatee and Braden Rivers below the reservoirs to provide a basis for assessing the 

risks associated with the use of copper sulfate in these systems. 

Strategy: Determine the loadings of copper from upstream sources and from inreservoir 

application of copper sulfate at Lake Manatee and the Bill Evers Reservoir. 

Develop and implement plans to reduce copper loadings to the reservoirs to achieve 

compliance with the state standard for dissolved copper in Class I waters. 

Develop and implement a sampling program to evaluate dissolved copper 

concentrations in the water column of sections of the lower segments of the Manatee 

and Braden Rivers, and copper concentrations in the sediments of the reservoirs and 

downstream segments of the rivers. 

Actions: 

1. Promote the collection and analyses of data on dissolved copper concentrations 

in Lake Manatee, the Bill Evers Reservoir and at sites upstream and 

downstream of each reservoir. In addition, promote collection and analyses of 

data on copper concentrations in the sediments of Lake Manatee and the Bill 

Evers Reservoir and in the sediments of the river segments downstream from 

the reservoirs. 

Responsible Parties: Southwest Florida Water Management District, Manatee 

County, City of Bradenton. 

Cost: $25,000. 


2. Produce a summary report of copper contamination in the Manatee River 

watershed which includes: 1.) a discussion of potential effects of copper on 

pelagic and benthic communities within the watershed, 2.) a copper loading 

model for the reservoirs and the lower segments of the Manatee and Braden 

Rivers, 3.) recommendations for maximum copper sulfate application rates for 

compliance with State water quality criteria, and 4.) an analysis of the feasibility 

of alternative water-treatment options (e.g. peroxide production) for reducing 

taste and odor problems associated with blooms of cyanobacteria in Lake 

Manatee and the Bill Evers Reservoir. 

Responsible Parties: Manatee County, City of Bradenton, Southwest Florida 

Water Management District. 


April 26, 2001 3-33 


Cost: $35,000 

Time-Frame: One year. 

3. Develop and implement a refined plan for the minimization or elimination of taste 

and odor problems associated with cyanobacteria blooms in Lake Manatee and 

the Bill Evers Reservoir, based on the summary report of copper contamination, 

loading, and alternative approaches to algal growth inhibition. 

Responsible Parties: Manatee County, City of Bradenton. 



Toxicant Pollution Issue #2 - Elevated levels of mercury, lead and zinc have been 

reported for sediments and the water column at various sites in the Manatee River 

watershed. However, comprehensive or recent data are lacking for much of the 

watershed. 

Background: The state of Florida has developed criteria for permissible levels of 

many metals in surface waters of the state, but has not established criteria for 

concentrations of metals in aquatic sediments. The Florida Department of 

Environmental Protection has, however, surveyed metal and hydrocarbon 

concentration in Florida estuaries and coastal water bodies and developed a list of 

sites with relatively high levels of these contaminants (FDEP 1994a). Mercury, lead 

and zinc were identified as contaminants of concern in Manatee River sediments (near 

the Braden River). Lead, mercury, and zinc concentrations exceeding state standards 

have been measured in water samples collected in the Manatee River upstream of 

Lake Manatee (Gee and Jenson Engineers, Architects, Planners, Inc., 1980, 1984). 

However, a recent survey of sediments in the Manatee River indicates that 

concentrations of metals in the watershed generally do not exceed background levels 

(Environmental Protection Commission of Hillsborough County, 1997). In the Braden 

River watershed, water column concentrations of most trace metals (other than copper) 

are also below state standards, although levels of mercury and silver may occasionally 

exceed state criteria (CCI Environmental Services, Inc. 1997a). To gain a better 

understanding of the extent of metals contamination in the watershed, a comprehensive 

assessment of metal concentrations in surface waters and in particular, the sediments 

of the entire Manatee River watershed is needed. 

Strategy: Evaluate sources and extent of metal contaminants in the Manatee River 

watershed. Develop appropriate strategies for reducing loads and remediation of 

contaminated sites, if necessary. 

Actions: 

1. Develop a report on metal contaminant issues for the Manatee River watershed 

that includes: 1) identification of all sites where data on metal concentrations has 

been collected during the last ten years; 2) identification of potentially 


April 26, 2001 3-34 


contaminated sites and sources of contamination; 3) determination of the need 

for a comprehensive metals monitoring program; 4) a plan for integrating and 

increasing accessibility of data on metal concentrations in the watershed; and 5) 

recommended strategies for reducing loadings of metals and mitigating 

contaminated sites, if necessary. 

Responsible Parties: United States Department of Agriculture Natural Resources 

Conservation Council, Florida Department of Environmental Protection, 



Cost: $50,000. 


2. Ensure compliance with NPDES permits. 

Responsible Parties: Florida Department of Environmental Protection. 

Cost: $0 

Time-frame: Ongoing 

Toxic Contaminants Issue #3 - Organic pesticides are used widely in the Manatee 

River watershed. Knowledge of the ecological impacts of pesticide use on 

aquatic ecosystems of the watershed is limited due to infrequent sampling at 

only a few sites within the watershed. 

Background: Pesticides may be introduced into aquatic ecosystems through direct 

application, stormwater runoff, or atmospheric deposition. These compounds pose a 

risk to aquatic flora and fauna and humans through direct toxic effects and 

accumulation, or biomagnification of toxicants in aquatic food webs. Semi-annual or 

quarterly sampling for several organic pesticides in the Braden River watershed above 

the Bill Evers Reservoir dam has not documented any violations of state pesticide 

standards for (EAC 1993, CCI Environmental Services, Inc. 1997, Smith and Gillespie 

Engineers, Inc. 1998). Sampling for organic pesticides in the Lake Manatee watershed 

has been limited to analyses of “finished” water leaving the water treatment plant. 

Organic pesticides exhibit differing levels of persistence in aquatic ecosystems. Some 

are unstable, breaking down in a few hours, while others persist for years (Nimmo 

1985). Transient pulses of pesticides associated with seasonal pesticide application 

and storm events may exert acute or chronic (persistent) toxic effects on populations 

and communities of aquatic organisms. A regular regime of sampling for residual 

pesticides in the water column and sediments throughout the Manatee River 

watershed, coupled with a program designed to ensure sampling during periods of 

pesticide application and following storm events would permit the characterization of 

potential toxic effects associated with pesticide use in the watershed. In addition, this 

sampling regime would provide information for evaluating the need for development 

and implementation of management practices for preventing potential pesticide 

contamination of the watershed’s aquatic systems. 


April 26, 2001 3-35 


Strategy: Evaluate the extent of organic pesticide contamination in the Manatee River 

watershed. If necessary, develop and implement strategies for reducing pesticide 

loading to aquatic systems. 

Actions: 

1. Develop a project for monitoring pesticide residuals in the Manatee River 

watershed that incorporates; 1) information on the types, quantities and 

application schedules of pesticides used in the watershed; 2) identification of the 

constituents most likely to cause toxic effects; 3) a sampling regime which 

accounts for seasonal and storm event pulses of pesticide runoff; and 4) 

chemical and toxicological analyses of water and sediment samples. 





Cost: $150,000. 

Time-Frame: Two years. 

2. If organic pesticide toxicity is established for sites within the watershed, initiate a 

project (or projects) to investigate management practices for eliminating or 

reducing pesticide contamination of aquatic systems. 





Cost: $150,000. 


3. Ensure compliance with NPDES permits. 

Responsible Parties: Florida Department of Environmental Protection. 

Cost: $0 

Time-frame: Ongoing 

3.5.4 Pathogens and Public Health Impacts 

Pathogens and Public Health Impacts Issue #1 - Fecal and total coliform bacteria 

abundances in many regions of the Manatee River watershed exceed state 

standards. 

Background: Violations of state standards (Chapter 62-302, F.A.C) for concentrations 

of total and fecal coliform bacteria occur in all segments of the Manatee River 

watershed. These standards are based on abundances of normally nonpathogenic 

coliform bacteria, which when present are thought to provide an indication of the 

presence of pathogens from mammalian fecal material. Excessive coliform levels are 

therefore typically associated with runoff from grazing lands and discharges from septic 


April 26, 2001 3-36 


or wastewater treatment systems. Unfortunately, the occurrence of populations of 

some bacteria (e.g. Klebsiella) commonly found in sediments or the water column may 

produce a false-positive indication of fecal contamination with current standardized 

tests (Knittel, 1975; Fujioka and Shizumura, 1985, SWFWMD 1994). New 

microbiological criteria being developed by the USEPA, based on abundances of 

specific groups of bacteria (e.g. Enterococci), protozoans and viruses, will provide 

better, corroborative evidence of fecal contamination and the potential for spread of 

infectious disease (USEPA 1993). 

The extent of false-positive coliform test results for the Manatee River watershed is 

unknown. Similarly, the full extent of pathogen contamination in the watershed is not 

known because of a lack of coordination among the various agencies responsible for 

microbiological sampling. 

Strategy: Support an investigation into the extent and sources of fecal contamination 

in the Manatee River watershed using nascent microbiological indicator methodologies. 

Actions: 

1. Maintain awareness of studies being conducted by the USEPA, FDEP and other 

agencies regarding the use of microbiological indicators for waterborne disease 

prevention. 

Responsible Parties: City of Bradenton, City of Palmetto, Manatee County, 

Sarasota County, Southwest Florida Water Management District, Florida 

Department of Environmental Protection. 

Cost: $0 


2. Develop and implement a comprehensive plan for monitoring microbial 

contamination throughout the Manatee River watershed, based upon the 

development of new federal and state criteria for microbiological indicators of 

fecal contamination and waterborne disease prevention. 

Responsible Parties: City of Palmetto, City of Bradenton, Manatee County, 

Sarasota County, Southwest Florida Water Management District, Florida 

Department of Environmental Protection. 


Time-Frame: Will be ongoing. 

3.5.5 Flow-Related Water Quality Problems 

Flow-related Water Quality Problems Issue #1 - Increased (and highly variable) 

salinity in lower segments of the Manatee and Braden Rivers. 

Background: The Florida Legislature has recently directed the State Water 

Management Districts to set minimum water levels and flows for surface waters of the 


April 26, 2001 3-37 


state. Minimum flow to a surface watercourse is defined in Section 373.042 of the 

Florida Statutes, as “the limit at which further withdrawals would be significantly harmful 

to the water resources or ecology of the area”. Section 373.942 of the Florida Statutes 

directs the Districts to use the best available data for setting minimum flows and levels. 

Factors to be considered in the determination of minimum flows and levels include 

recreational use, fish and wildlife habitats, estuarine resources, detrital pathways and 

processing, storage of freshwater supplies, aesthetic qualities and nutrient assimilation 

capacity. According to the state-mandated schedule, the Southwest Florida Water 

Management District must establish minimum flows for the Braden and Manatee Rivers 

by the year 2005. 

The installation of dams on the Braden and Manatee Rivers has impacted flow regimes 

in the lower segments of these rivers. Recent modeling efforts have identified 

substantial differences between current and pre-alteration (dam construction) flows and 

locations of the freshwater/saltwater front (halocline) in the Manatee River (e.g. Dames 

and Moore and Mote Marine Laboratory 1994, Camp, Dresser and McKee Inc., 1995; 

Coastal Environmental Inc., 1995). Differences are attributed to reservoir withdrawals, 

reservoir releases and waste water discharges. 

Changes in salinity and flow regime may profoundly influence the colonization and use 

of habitat by aquatic organisms. Investigations of the biological communities of the 

lower Manatee and Braden River segments (e.g., Mote Marine Laboratory 1992, 

Dames and Moore and Mote Marine Laboratory 1994, CCI Environmental Services, Inc. 

1997b), should provide the basis for sound determination of minimum flows. 

Strategy: Use existing data and reports, and collect additional data, as needed, to 

establish minimum flows for the Manatee and Braden Rivers. 

Actions: 

1. Set the minimum flow for the Braden River. 

Responsible Party: Southwest Florida Water Management District. 

Cost: Unknown 


2. Set the minimum flow for the Manatee River. 

Responsible Party: Southwest Florida Water Management District. 



3. Implement minimum flows for the Braden and Manatee Rivers. 

Responsible Parties: City of Bradenton, Manatee County. 

Cost: Unknown 

Time-Frame: Will be ongoing. 


April 26, 2001 3-38 


3.5.6 Data Gaps and Monitoring Needs 

Data Gaps and Monitoring Needs Issue #1 - Water quality data is lacking for 

certain regions of the Manatee River watershed, and existing monitoring 

programs are not well coordinated. 

Background: Water-quality data for reservoir, stream and river sites in the Manatee 

River watershed are currently being collected by several parties for a variety of uses, 

including drinking-water production, compliance with water use, NPDES and other 

permits, and for evaluation of Development of Regional Impact proposals. The 

diversity of data requirements of the various parties involved in water quality 

management within the watershed often limits the usefulness of the data for purposes 

other than those of the original data collector. In addition, mechanisms for efficient 

transfer of water quality data among water management groups are not fully developed. 

This lack of coordination among data collection programs limits the capacity of water 

managers to adequately address water quality issues, including the effects of changing 

land-use, on a watershed basis and hinders the analyses of water quality trends and 

the development of constituent loading models and Total Maximum Daily Load 

estimates. Furthermore, although most sub-basins within the watershed are included in 

one of the various water quality sampling programs, key sites within some sub-basins 

are not currently monitored. 

Coordinated collection of water quality data at key sites throughout the watershed 

would: 1.) compliment existing sampling programs to ensure the collection of 

comprehensive water quality data for the watershed; 2.) minimize redundant sampling 

and associated costs; 3.) improve the ability of water managers to detect violations or 

non-compliance with state and local water quality standards and the development of 

Total Maximum Daily Loads; and 4.) provide the opportunity for land developers, and 

other permit applicants to acquire (through monetary support of the comprehensive 

water collection network) water quality information necessary for fulfilling permit 

requirements. 

Strategy: Develop and implement a plan to develop a comprehensive water quality 

data collection network for the Manatee River watershed. 

Actions: 

1. Continue to support the Comprehensive Watershed Management initiative in the 

Manatee River watershed and thus ensure the existence of a forum for the 

discussion of water-quality data, issues and management goals for the 

watershed. 

Responsible Parties: Southwest Florida Water Management District, United 

States Department of Agriculture Natural Resources Conservation Council, 

Florida Department of Environmental Protection, Manatee County, Sarasota 

County, City of Bradenton, City of Palmetto, interested citizens. 


April 26, 2001 3-39 



Time-Frame: Ongoing 

2. Develop a report on water quality monitoring issues for the Manatee River 

watershed that includes: 1.) identification of all sites where water quality data 

has been collected during the last twenty years; 2.) a map showing the locations 

of all current or recent water-quality monitoring stations along with sampling 

coordinators and parameters measured; 3.) an evaluation of the utility of the 

suite of parameters currently monitored, and if necessary, recommendations for 

additional parameter measurement; 4.) a map showing proposed monitoring 

sites; 5.) a plan for increasing accessibility of watershed water quality 

information; and 6.) a plan for the development of mechanisms for permit 

applicants and other parties requiring water quality data to provide monetary 

support for the data collection network. 

Responsible Parties: Southwest Florida Water Management District, United 

States Department of Agriculture Natural Resources Conservation Council, 

Florida Department of Environmental Protection, Manatee County, Sarasota 


Cost: $50,000. 



Ayres Associates. 1995. An estimate of nutrient loadings from wastewater residuals 

management and onsite wastewater treatment systems in the Tampa Bay area. 

Tampa, Florida. Prepared for the Southwest Florida Water Management 

District, Brooksville, Florida. 

Blanchard, G. 1997. Analysis of nutrient loads to the Lake Manatee and Evers 

Reservoir watersheds, 1990-1994. Memorandum to R. Brown, Manatee County 

Environmental Management Department, Bradenton, Florida, March 20, 1997. 

Camp, Dresser and McKee, Inc. 1984. Manatee County Public Utilities Department 

water supply master plan (1983-2013). Bradenton, Florida. Prepared for the 


Public Utilities Department, Bradenton, Florida. 

Camp, Dresser and McKee, Inc. 1985. Southeast area stormwater management study: 

final report. Bradenton, Florida. Prepared for Manatee County Planning and 

Development Department, Bradenton, Florida. 

Camp, Dresser and McKee, Inc. 1994. Tampa Bay tributary loading project. 

Bradenton, Florida. Prepared for the Tampa Bay National Estuary Program, St. 

Petersburg, Florida. 


April 26, 2001 3-40 


Camp Dresser and McKee, Inc. 1995. Freshwater releases from Lake 

Manatee–effects on Manatee River salinity and future water supply. Bradenton, 

Florida. Prepared for the Manatee County Public Service Department, 

Bradenton, Florida. 

Camp, Dresser and McKee, Inc. 1996. Part 2 NPDES municipal separate storm sewer 

system permit application. Bradenton, Florida. Prepared for Manatee County, 


CCI Environmental Services, Inc. 1997a. Data summary and interpretative report for 

the Bill Evers Reservoir and Braden River water quality monitoring program: 

October 1992-September 1996. Palmetto, Florida. Prepared for Smith and 

Gillespie Engineers, Inc., Jacksonville, Florida. 

CCI Environmental Services, Inc. 1997b. A summary of physical, chemical and 

biological studies of the tidal Braden River. Palmetto, Florida. Prepared for the 

City of Bradenton, Florida. 

CH2M Hill. 1984. Recharge-recovery at Lake Manatee: phase II. Gainesville, Florida. 

Prepared for the Southwest Florida Water Management District, Brooksville, 


Clarke, R. A., Jr. (1995). An analysis of water quality trends for Lake Manatee, Florida. 

Master’s Thesis, University of Florida, Gainesville. 

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Relationship of seasonal water quality to chlorophyll a concentration in Lake 

Manatee, Florida. Journal of Lake and Reservoir Management, 13: 253-258. 

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total suspended solids loadings to Tampa Bay, Florida. St. Petersburg, Florida. 

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Coastal Environmental, Inc. 1996. Estimates of total nitrogen, total phosphorus, and 

total suspended solids loadings to Tampa Bay, Florida, technical appendix: 

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Florida. Prepared for the Tampa Bay National Estuary Program, St. Petersburg, 



April 26, 2001 3-41 


Coastal Environmental, Inc. 1997. Watershed management model for optimization of 

best management practices: user’s guide and case study. St. Petersburg, 

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variation in the Manatee River. Tampa and Sarasota, Florida. Prepared for the 

Tampa Bay National Estuary Program, St. Petersburg, Florida. 

DeGrove, B. D. 1986. Manatee River water quality based effluent limitation 

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Tallahassee, Florida. 

Drew, R. D. 1990. Hydrology and water quality. Pages 56-133 in Wolfe, S. H., and 

Drew, R. D. (eds.), An ecological characterization of the Tampa Bay watershed. 

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Duerr, A. D., Hunn, J. D., Lewelling, B. R., and Trommer, J. T. 1988. Geohydrology 

and 1985 water withdrawals of the aquifer system in southwest Florida, with 

emphasis on the intermediate aquifer system. United States Geological Survey 

Water Resource Investigations Report 87-4529. 

Environmental Action Commission of Manatee County. 1993. Evers Reservoir 

watershed baseline water quality monitoring, 1988-1992, final report. 

Bradenton, Florida. Prepared for the Southwest Florida Water Management 

District, Brooksville, Florida. 

Environmental Protection Commission of Hillsborough County. 1997. Trace metal 

status of Tampa Bay sediments 1993-1996. Tampa, Florida. Prepared for the 

Tampa Bay National Estuary Program, St. Petersburg, Florida. 

Environmental Science and Engineering, Inc. 1977. Assessment of water quality 

problems in the Tampa Bay region - update. Tampa, Florida. Prepared for the 

Tampa Bay Regional Planning Council, St. Petersburg, Florida. 

Flannery, M. S. 1989. Tampa and Sarasota Bays: watersheds and tributaries. Pages 

18-48 in Estevez, E. D. (ed.), Tampa and Sarasota Bays: issues, resources, 

status, and management. NOAA Estuary-of-the-month Seminar Series No. 11, 

United States Department of Commerce, National Oceanic and Atmospheric 

Administration, NOAA Estuarine Programs Office, Washington, D.C. 


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FDEP (Florida Department of Environmental Protection). 1994a. Florida water quality 

assessment 1994 305(b) main report and technical appendix. Bureau of Surface 

Water Management, Tallahassee, Florida. 

FDEP (Florida Department of Environmental Protection). 1994b. Ground water 

guidance concentrations. Bureau of Drinking Water and Ground Water 

Resources, Tallahassee, Florida. 

FDEP (Florida Department of Environmental Protection). 1996. 1996 Water-quality 

assessment for the State of Florida, Section 305(b) main report and technical 

appendix. Bureau of Water Resources Protection, Tallahassee, Florida 

Florida Department of Natural Resources. 1992. Comprehensive shellfish harvesting 

area survey of Lower Tampa Bay, Manatee County, Florida. Shellfish 

Environmental Assessment Section, Tallahassee, Florida. 

Fujioka, R. S. and Shizumura, L. K. 1985. Clostridium perfringens, a reliable indicator 

of stream water quality. Journal of the Water Pollution Control Federation 57: 

986-992. 

Gee and Jenson Engineers, Architects - Planners, Inc. 1981. Lake Manatee water 

resource evaluation, phase I - baseline analysis of existing watershed. West 

Palm Beach, Florida. Prepared for the Manatee County Board of County 

Commissioners, Bradenton, Florida. 

Gee and Jenson Engineers - Architects - Planners, Inc. 1984. Lake Manatee 

watershed water resources evaluation, phase II - safe yield and impact 

assessment (3 volumes). West Palm Beach. Prepared for the Manatee County 

Utilities Department, Bradenton, Florida. 

Heyl, M. G. 1982. Manatee River ecological study: a technical basis for best 

management practices. Final Report, OCM contract number CM-51, Florida 

Department of Environmental Regulation, Office of Coastal Management, 


Huber, W. C., Brezonik, P. L., Heaney, J. P., Dickinson, R. E., Preston, S. D., Dwornik, 

D. S., and DeMaio, M. A. 1982. A classification of Florida lakes. Florida 

Department of Environmental Regulation, Tallahassee, Florida. 

IMC Agrico Co. 1997. Four Corners Mine 1996/1997 annual report. Mulberrry, 

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Department, Bradenton, Florida. 

Knittel, M. D. 1975. Occurrence of Klebsiella pneumoniae in surface waters. Applied 

Microbiology 29: 595-597. 


April 26, 2001 3-43 


Leland, H. V. and Kuwabara, J. S. 1985. Trace metals, pp. 374-415, in Rand, G. M and 

Petrocelli, S. R. (eds.): Fundamental of aquatic toxicology. Hemisphere 

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Tampa Bay: incidence, severity, and spatial distribution. Florida Scientist 58: 

163-178. 

Manatee County Environmental Management Department. 1998. Water quality 

monitoring programs operated by Manatee County Environmental Management 

Department. Bradenton, Florida. 

Manatee County Public Works Department. 1986. Water quality investigation #6. 


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Downstream effects of permitted and proposed withdrawals from the Lake 

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Water Management District, Brooksville, Florida. 

McNeal, B. L., Stanley, C. D., Graham, W. D., Gilreath, P. R., Downey, D., and 

Creighton, J. F. 1995. Nutrient-loss trends for vegetable and citrus fields in 

west-central Florida: I. nitrate. Journal of Environmental Quality 24: 95-100. 

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interconnected aquifers in west-central Florida. United State Geological Survey 

Water Resources Investigations, Report 96-4030. Tallahassee, Florida. 

Miller, J. A. 1986. Hydrogeologic framework of the Floridan aquifer system in Florida 

and parts of Georgia, Alabama, and South Carolina. United States Geological 

Survey Professional Paper 1403-B. 

Montgomery Watson. 1997. Technical memorandum for basis of design: potable water 

aquifer storage and recovery system expansion at the Lake Manatee Water 

Treatment Plant. Tampa, Florida. Prepared for Manatee County Government, 


Mote Marine Laboratory. 1992. Identification, classification, and inventory of critical 

nursery habitats for commercially and recreationally important fishes in the 

Manatee River estuary system of Tampa Bay. Sarasota, Florida. Submitted to 

the Southwest Florida Water Management District, Brooksville, Florida. 


April 26, 2001 3-44 


Nimmo, D. R. 1985. Pesticides, pp. 374-415, in Rand, G. M and Petrocelli, S. R. 

(eds.): Fundamental of aquatic toxicology. Hemisphere Publishing Corporation, 

New York, New York. 

QST Environmental, Inc. 1998. Draft final report Four Corners Mine monitoring: year 

two July 1996-June 1997. Tampa, Florida. Prepared for the Manatee County 

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Schroeder-Manatee, Inc. 1991. University Place development of regional impact: 

application for development approval. Bradenton, Florida. 

Smith and Gillespie Engineers, Inc. 1971. Engineer’s preliminary report on Braden 

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regional impact: application for development approval under Section 380.06, 

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Geological Survey Special Publication Number 28. 

Stanley, C. D., McNeal, B. L., Gilreath, P. R., Creighton, J. F., Graham, W. D., and 

Alverio, G. 1995. Nutrient-loss trends for vegetable and citrus fields in westcentral 

Florida: II. phosphates. Journal of Environmental Quality 24: 101-106. 

Swancar, A. and Hutchinson, C. B. 1992. Chemical and isotopic composition and 

potential for contamination of water in the Upper Floridan Aquifer, west-central 

Florida, 1986-1989. United States Geological Survey Open Filer Report 92-47. 

SWFWMD (Southwest Florida Water Management District). 1988. Ground-water 

resource availability inventory: Manatee County, Florida. Brooksville, Florida. 


quality of the Southwest Florida Water Management District: southern region 

Section 2. Brooksville, Florida. 

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water improvement and management plan. Brooksville, Florida. 


April 26, 2001 3-45 


SWFWMD (Southwest Florida Water Management District). 1993. Eastern Tampa 

Bay water resource assessment project. Brooksville, Florida. 

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River diagnostic/feasibility study. Brooksville, Florida. 

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Oneco monitor well site, Manatee County, Florida. Brooksville, Florida. 


quality sampling from wells in the Southwest Florida Water Management District: 

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application for approval. Manatee County, Florida. 

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comprehensive conservation and management plan for Tampa Bay. St. 

Petersburg, Florida. 

Tampa Bay Regional Planning Council. 1977. Reservoir protection plans for the 

Tampa Bay region. St. Petersburg, Florida. 

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measures for the Tampa Bay region. St. Petersburg, Florida. 

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and Braden Rivers. St. Petersburg, Florida. 

Tara Development, Ltd. 1980. Tara, a panned unit development Manatee County, 

Florida, development of regional impact application for development approval. 

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Trommer, J. T., DelCharco, M. J., and Lewelling, B. R. 1999. Water budget and water 

quality of Ward Lake, flow and water-quality characteristics of the Braden River 

estuary, and the effects of Ward Lake on the hydrologic system, west-central 

Florida. U.S. Geological Survey Water-Resources Investigations Report 98- 

4251. Tallahassee, Florida. 

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April 26, 2001 3-46 


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Wilbur Boyd Corporation. 1984. Cooper Creek Center development of regional impact 

application for development approval. Bradenton, Florida 


April 26, 2001 3-47 


Chapter 4 

4.0 FLOOD PROTECTION 

4.1 Introduction 

The two most common causes of natural flooding are heavy-volume rainfall and tidal 

surges from tropical storms. A storm surge is the primary factor causing flooding along 

the Florida coast while heavy-volume rainfall can cause flooding almost anywhere. 

Storm surges are higher than normal tides created by onshore winds associated with 

hurricanes and other tropical storms. Surges over 10-feet high can occur posing a 

significant threat to structures along the coast by inundation and wave action. On the 

other hand, heavy-volume rainfall occasionally generates runoff rates that exceed the 

transport capability of a stream resulting in severe over bank flooding. Areas subject to 

over bank flooding are considered floodplains. Floodplains are defined as low areas 

adjacent to streams, lakes, and oceans that are subject to flooding once every 100 

years. The 100-year frequency is important in the definition of a floodplain because it 

is the standard used by the National Flood Insurance Program. However, “big” floods 

of more frequent return intervals (less than the 100-year) are still possible within a 100- 

year floodplain. 

People throughout history have settled next to waterways, because of the advantages 

they offer in transportation, commerce, energy, water supply, soil fertility, recreation, 

aesthetics, and waste disposal. In spite of these benefits, the historic attraction to 

settle along rivers, streams, and coastal areas not without consequences. Floods have 

caused a greater loss of life and property, and have disrupted more families and 

communities in the United States than all other natural hazards combined. Floods in 

the United States have resulted in property damage in excess of $2.2 billion per year, 

and in the 1970s, flood-related deaths averaged 200 per year, with another 80,000 

people being forced from their homes per year (U. S. Water Resources Council, 1981). 

Until the 1970s, water resource planning methodology was dominated by the economic 

benefits they provided. The Flood Control Act of 1936 defined an acceptable federal 

flood control project as one that “the benefits, to whomever they may accrue, are in 

excess of the estimated costs.” As time progressed, this definition expanded to include 

the economic contributions to the national income. Thus, the main objective became 

the maximization of the combined net monetary benefits to all parties affected by a 

water resource project. 

In the 1970s, people’s concerns for environmental quality and social welfare increased 

beyond just the consideration of the national economic benefits. As a result, a set of 

water resources planning procedures (Water Resources Council’s Principles and 

Standards) was adopted by presidential order in 1973 and revised in 1979. Two 

objectives now had to be met by a federal water resource project: 


April 26, 2001 4-1 

Chapter 4 - Flood Protection

1. National economic development: “Enhance national economic 

development by increasing the value of the Nation’s output of goods and 

services and improving national economic efficiency.” 

2. Environmental quality: “Enhance the quality of the environment by the 

management, conservation, preservation, creation, restoration, or 

improvement of the quality of certain natural and cultural resources and 

ecological systems.” 

With the addition of environmental quality objectives to those of flood control and 

economic benefits, state water policy has now adopted a holistic approach to surface 

water planning. Natural habitat preservation, water quality, and water supply are also 

important factors to consider regarding flood control projects. A balance between these 

objectives is necessary when surface alterations are required to render an area 

suitable for human occupancy. 

Historically, enhanced drainage was the primary method used to reduce flood damage. 

For example, if an area was subject to high-volume rainfall flooding, a canal system 

was created or the existing drainage system enhanced to remove surface water at a 

faster rate. A review of the historical surface water management proposals for the 

Manatee Watershed revealed that enhanced channel capacity was the most cost 

effective method for reducing flood levels. However, in view of the environmental 

aspects of flood control this approach is no longer tenable. 

The primary focus of this section is to review previous studies that generally identify 

flood prone areas. Distinguishment between developed and undeveloped flood prone 

areas will be necessary because their mitigation approaches can be different. In 

undeveloped watersheds, floodplains and water levels can be identified which will allow 

proper management of domestic construction in flood prone areas while concurrently 

maximizing the environmental quality objectives. In developed watersheds, a more 

sophisticated approach may be necessary to relieve flooding and prevent exacerbation 

of the present problems. In these watersheds, land availability may limit flood relief 

and environmental objectives. 

Cooperation with local governments will be a key component of the flood protection 

process. Land use planning, stormwater planning, and funding are items that require 

due consideration. Long-term planning and partnerships between various state and 

local governments will be necessary to meet the specified goals. It will be the 

responsibility of the CWM team to provide the direction and assistance that promotes 

these goals. 

In addition, the SWFWMD is developing a Flood Protection Coordination Initiative 

(FPCI) to address management strategies and responsibilities associated with flood 

protection within a county. Each county will be subdivided into management units, 

typically subbasins, to identify areas of concern. Within in each of these management 


April 26, 2001 4-2 


units aerial mapping, floodplain analysis, conveyance, maintenance projects, etc. will 

be identified for achieving the flood protection goals. Most of the strategies and actions 

discussed in this section of the CWM plan will be incorporated into a FPC document. 

Flood protection responsibilities of the SWFWMD, County, and Municipalities will be 

defined. The FPC will be used to identify and plan for flood protection projects on a 5- 

year basis. 

4.2 General Description of Watershed and Community 

Manatee County occupies an area of approximately 742 square miles in west-central 

Florida. It is bordered on the north by Hillsborough County, on the east by Hardee and 

DeSoto counties, Sarasota County lies to the south, and the Gulf of Mexico is located 

to the west. Bradenton is the county seat and is the largest city in the county. Major 

riverine systems within the county are the Manatee, Braden, Little Manatee, and 

Myakka rivers. The largest riverine system is the Manatee River which has its 

headwaters in the northeastern part of the county and flows westerly between the cities 

of Bradenton and Palmetto to the Gulf of Mexico. The Manatee River is about 45 miles 

long and drains a watershed of approximately 360 square miles. Braden River is a 

tributary of Manatee River watershed, is about 19 miles long, drains a watershed area 

of approximately 80 square miles, and is included in the 360 square mile drainage area 

of the Manatee River. The remaining riverine systems of the county are discussed in 

other CWM plans. 

Western Manatee County is characterized by floodplains that are nearly level to level 

and a gently sloping terrain while higher, gently rolling areas characterize the central 

and northeastern portions of the county. No major lake systems exist within the county 

except for Lake Manatee and the Evers Reservoir which are manmade impoundments 

created within the Manatee and Braden Rivers. Nevertheless, numerous intermittent, 

shallow ponds occupy the watershed primarily in the central and eastern portions of the 

county. Land elevations range from sea level along the coastal areas to about 150 feet 

in the northeastern portion of the county. 

The runoff potential for the Manatee River watershed is quite high since most of the 

soils are classified as poorly drained sandy soils with an organic pan that impedes 

vertical movement of water. Most of the soils have a B/D, C, or D classification which 

are classified as moderate to high runoff soils. Most of the rainfall occurs during the 

wet season of June through September which also corresponds to the hurricane 

season. A review of daily rainfall records from the National Weather Service Station at 

Bradenton was used to provide indications of potential flood situations in the Manatee 

River Watershed. The period of record used in the analysis included years 1911-1987. 

Some years were eliminated from the record due to missing data. Rainfall cumulations 

greater than or equal to 8.0 inches over a 5-day period were used to identify rainfall 

conditions when flooding was possible within the watershed. 


April 26, 2001 4-3 


The analysis showed that approximately 24 rainfall events occurred over this period 

meeting this criteria. Corresponding dates for these events were cross referenced to 

tropical storm and hurricane occurrences (National Oceanic and Atmospheric 

Administration, 1987). Over half of the events corresponded to cyclonic disturbances 

that passed within the vicinity of the Manatee River watershed. In addition to flood 

situations due to large rainfalls, tidal surges in the coastal areas resulting from 

hurricanes and tropical storms pose a significant threat. High onshore winds can 

produce tides that can inundate barrier islands and low lying areas along and well 

inland of the coast. Susceptibility is quite high since the Manatee River has a broad 

estuary. 

Protection of inhabitants and their structures from these flood damaging situations is 

the major focus of this section of the report. In 1970, the U.S. Bureau of the Census 

recorded a population of 97,115, which is 40% greater than the 1960 population 

census of 69,168. The current population of Manatee County is 223,508 (1995 

Census) and is primarily located along the more coastal areas which are subject to tidal 

surges. 

Agriculture is the predominant land use within the county with rowcrops, pasture, and 

citrus groves representing the major categories. Urban land uses predominate along 

the western portion of the county. Commercial areas can be found along the gulf coast 

and U.S. Highway 41 while industrial developments are generally located along U.S. 

Highway 301 and the Seaboard Coast Line Railroad. 

According to the 1990 Land Use and Land Cover for the Manatee River Watershed, 

Urban and built-up land uses occupy 29,367 acres or 12.73% of the total basin area. 

However, only a small portion of the urban area is located within Federal Emergency 

Management Administration (FEMA) designated flood prone areas. Urban and built-up 

land uses within the FEMA 100-year Flood Zone are estimated at 3,343.86 acres or 

11.38% of the total urban land cover. These areas are subject to local and tidal flood 

conditions. This percentage of urban flood prone areas suggests that flood protection 

may be an issue within the watershed. The number of structures within these areas 

that are below the FEMA base flood elevations is unknown. 

4.3 Historic Floods of Record 

As previously mentioned, some of the cyclonic storms that passed within the vicinity of 

the Manatee River Watershed produced severe floods and structural damage. A brief 

summary of five of those storms is presented (FEMA, 1992) in order to provide a 

historical perspective of the flood hazards and depths. Two of the most recent storms 

that caused flooding are also provided. Tidal surges caused most of the damage, 

however, other damaging events were the result of the combinational effect of a surge 

and heavy rainfall. This historical presentation points out the potential trend of flood 

damaging conditions when preventative measures are not pursued. Given the 

experience of these past events, a stimulus was generated to establish guidelines and 


April 26, 2001 4-4 


flood management systems to protect the citizens and minimize the damage from 

extreme storm events. 

October 21-31, 1921 

This storm began in the Western Caribbean Sea and intercepted Florida north of the 

City of Tarpon Springs. Flooding conditions were protracted due to the slow movement 

of the storm. Anna Maria Key and Cortez were inundated with four to five feet of water. 

Substantial property damage and agricultural losses were sustained within Manatee 

County as a result of the tidal surge. 

September 11-22, 1926 

At the time, this was one of the most destructive storms of the century for Florida. It is 

may only be surpassed by Hurricane Andrew (August, 1992) which resulted in property 

loss in the billions of dollars. The 1926 storm originated in the Atlantic Ocean near the 

Cape Verde Islands and approached the Florida coast on September 17. Waves 

caused erosion along the Manatee County coast and severe flooding in the Bradenton 

Area. Statewide the Storm damage was estimated at $100 million, with $3 million in 

the Bradenton, Sarasota, and Fort Myers areas. 

September 7, 1950 

This was a compact, but severe, hurricane that originated in the western Caribbean 

Sea, that passed northward over Aruba and the Gulf of Mexico, then moved north and 

parallel to the Florida coastline. Surges were estimated between 6 and 8 feet along the 

central gulf coast. Much of Anna Maria Island was flooded. Wave action eroded the 

shoreline 15 to 20 feet in some areas and cut through the beach road on the island in 

several places. 

September 10-11, 1960 

Precipitation from Hurricane Donna averaged only 5 to 7 inches, but the previous 3 

week rainfall of approximately 10 inches had saturated the ground which exacerbated 

the flood situation. In addition, storm tides caused substantial damage to the Manatee 

County coastal areas. 

June 19, 1972 

Hurricane Agnes formed on the northeastern tip of the Yucatan Peninsula and 

progressed westward. Although the center of the storm passed about 150 miles west of 

the Florida peninsula, it still produced a high, damaging tidal surge due to its massive 

size. Tides were approximately 3 to 4 feet above normal. The high tide in conjunction 

with wave action caused damage to homes, seawalls, revetments, and roads. Damage 

in Manatee County was estimated a $2 million. 


April 26, 2001 4-5 


May, 1995 

December, 1997 

From the month of December 1997 through the month of March 1998, the phenomena 

El Niño created several cyclonic storms that produced large amounts of rainfall through 

successive storm events in the Manatee River Watershed. Some of these rainfall 

events caused significant flood damage to homes in newly developed areas within the 

Manatee and Braden River Watershed. Flood levels were approximately 3 to 4 feet 

above the predicted 100-year flood levels in certain areas. The extent of the flood 

damage is unknown. 

4.4 Flood Hazard Information 

The July 15, 1992, Revised Flood Insurance Study performed by FEMA for Manatee 

County, used information from unpublished and published flood studies to establish 

water surface profiles for the rivers and tributaries associated with the Manatee River 

watershed . Storm surges effects were integrated into the water surface profiles 

provided. Establishment of coastal flood levels was performed using the FEMA 

standard coastal surge model. Water surface profiles for the 10-, 50-, 100-, and 500- 

year recurrence intervals were generated using the step-backwater model, HEC-2 . 

Peak discharge rates along river reaches were developed using the United States 

Geological regional regression equations developed for the area. Drainage basin 

areas, slopes, and lake areas are parameters used in the regional regression 

equations. After the water surface profiles were established for the rivers and 

tributaries, floodplain boundaries were added to the Flood Insurance Rate Maps to 

identify flood hazard areas. 

4.5 Summary of Stormwater Management Studies 

Several flood studies have been performed in the Manatee River Watershed to develop 

causal and relief alternatives for flooding conditions within the watershed. The purpose 

of this section is to identify those studies and provide a brief overview of their scope. 

Management analyses have also been performed to minimize the flood hazards 

associated with operating the Manatee Reservoir. The reservoir is used to store 7.5 

billion gallons of water to provide a reliable source of potable water at a withdrawal rate 

of approximately 30 plus million gallons a day. The reservoir is operated in such a 

way that the earthen dam used to create the reservoir is not compromised, thus 

creating a hazardous situation downstream. 

4.5.1 Stormwater Management Studies 

Reynolds, Smith and Hills - Architects - Engineers - Planners - Incorporated, 

“Floodplain Study for the Lower Manatee River Manatee County, Florida,” March, 

1982. 


April 26, 2001 4-6 


The Study indicated that substantial flooding of residences along the Lower Manatee 

River has frequently occurred in the past. The Lower Manatee River is characterized 

as the downstream portion of the river from the Lake Manatee Reservoir Dam. The 

study encompassed the area from I-75 to the dam and part way up some of the 

tributaries. Five, ten, twenty-five and one-hundred year flood levels have been 

developed. It appears that tidal surges were not considered in the analysis. A 

hydrodynamic model was used to simulate the flood profile. A 10.58 inch rainfall 

generated a peak discharge of almost 10,000 cfs for a 90 square-mile area. A storm 

duration of seventy-two hours was used in the simulations. Three radial tainter gates 

regulate the discharge from the Manatee Reservoir. Recommendations for flood 

releases from the reservoir via the gates were as follows: starting at a water surface 

elevation of 40 feet above mean sea level, discharges would be increased until a 

maximum release rate of 15,900 cfs would be achieved at a water surface elevation of 

41.0 feet and a gate opening of 12.7 feet. Maximum water surface elevation levels 

ranged from 3.63 feet near I-75 to 27.98 feet just below the dam. In addition, a dam 

failure analysis was performed on the reservoir using the National Weather Service 

Model DAMBRK. Results from the modeling generated the impetus for the creation of 

an emergency spillway to maintain dam integrity. 

Camp Dresser & McKee, Inc., “Lake Manatee Reservoir Regulation Manual,” 

November 1983. 

A monitoring system was established for the Manatee Reservoir for flood regulation. 

Soils, land use, etc. were analyzed to make predictions regarding runoff. Lake 

Manatee impounds 15,800 acre-feet of water between water surface elevations of 27.3 

and 40.0 feet and occupies 1850 acres at a water surface elevation of 40 feet. The 

outfall is a 108 foot Ogee spillway regulated by three tainter gates. Eight fuse plug 

emergency spillways exist at a minimum elevation of 44 feet. Small storms can be 

controlled by operating the gates within a maximum reservoir level of 41.0 feet. 

Discharges under these conditions can stay within the river bank. Five- to twenty-five 

year events can be controlled between elevations of 41.0 and 42.5 feet, and 25- to 100- 

year events can be controlled between elevations of 42.5 and 44.0 feet. Between 

16,000-18,000 cfs can be discharged at the maximum controllable elevation. At 46.0 

feet, however, the earthen berms are overtopped yielding uncontrolled discharge. 

Reservoir inflow at the 100-year event is estimated at 29,000 cfs. Evacuation of 

downstream residents is a major concern because over bank capacity begins with 

storms of 6 inches or greater within 24-hours. Therefore, anything with a rainfall 

forecast greater than 4 inches under wet conditions and relative high reservoir levels 

should be treated seriously. 

Manatee County Comprehensive Plan, May 15, 1998. 

Chapter nine of the Manatee County Comprehensive Plan contains information 

concerning Stormwater Quantity and Quality. The plan dictates that the primary water 

surface structures must convey runoff from a 25-year 24-hour event. Drainage 

structures within developments must use a design standard of a 10-year critical 


April 26, 2001 4-7 


duration. Construction of retention/detention facilities must increase the time of 

concentration of a watershed. They are to be safe and aesthetically pleasing. 

Manatee County Public Works Department Engineering Division, “Stormwater 

Management Design Manual,”, December 11, 1990. 

This manual provides the guidelines and methodologies to be employed for the design 

of water conveyance systems. Basically the 25-year 24-Hour storm design criteria 

must be followed unless the proposed system is located within a know flooding area or 

in a restrictive outfall situation. If these conditions prevail, then the system design is 

more stringent. Manatee guidelines are very similar to those imposed by the District. 

For designs located in the Evers and the Lake Manatee watersheds, and along the 

coast an addition 50% increase in water quality treatment is required. Internal drainage 

of a development is based on a 10-year return storm. The County has the provision 

that the road base has to be one-foot above the seasonal high water table. Facility 

ownership and maintenance guidelines are provided within the Manual. 

Wanielista, M. P., “Evers Reservoir Hydrologic Study”, September 1989. 

The results of the study indicate that most of the streamflow is from baseflow and fast 

moving interflow. Therefore, the recommendation is that development within the Evers 

Reservoir watershed should preserve these characteristics of both water quantity and 

quality. In addition, there was indication of a slow moving groundwater flux. Baseflow 

analysis suggests that 80-90% of the stream flow comes from groundwater infiltrating 

into the tributaries and river. As a result, only 10-20% of the annual streamflow is from 

direct runoff. Consequently it was recommended that a stormwater plan return 90% of 

the runoff waters to the groundwater system. This conclusion could be extrapolated to 

the Manatee River Basin also. Design criteria were specified for the ponds to meet the 

overall objectives. 

USACE, “Special Flood Hazard Information Report Manatee & Braden Rivers, 

Manatee & Sarasota Counties, Fl,” December 1972. 

This report is interesting in that it indicates that a 110-foot section of the Evers 

Reservoir Dam collapsed during a hurricane which resulted in contamination of the 

fresh water supply. The elevation of the weir is important in regard to tidal surges and 

potential contamination by seawater. 

USACE, “Survey Report on Manatee & Braden Rivers,” 1971. 

The Manatee River watershed encompasses 330- square miles which includes 83 

square-miles of the Braden River. Five thousand acres were in urban land use in 1970. 

The Army Corps of Engineers had proposed channel widening of 23.75 miles of 

Manatee River for Navigation. Various Harbor Acts between 1882 and 1905 authorized 

the project which was completed in 1915. Summary of those projects are as follows: 

Channel from Tampa Bay to NcNeil Point - 100 feet wide, 13 feet deep. 

From NcNeil Point to Rocky Bluff - 100 feet wide, 9 feet deep. 

From Rocky Bluff to Rye Bridge - 75-wide channel, 4 feet deep. 


April 26, 2001 4-8 


6-foot-deep, 100-foot-channel from Manatee River into Terra Ceia Bay. 

Manatee Dam was created in 1968 while the Evers Reservoir was constructed in 1936. 

Flows in excess of 3500 cfs below the Manatee Dam cause flooding at Rye Ridge. 

Braden River flooding occurs near HWY 70. 

Camp Dresser & McKee, “Southeast Area Stormwater Management Study,” 

September 1985. 

This report investigated various development scenarios for the Evers Reservoir 

Watershed along with their effects on runoff volumes. Evers Reservoir is the primary 

drinking water source for the City of Bradenton. The reservoir was expanded in 

capacity from 0.585 billion gallons to 1.404 billion gallons by expanding the surface 

area from 130 to 354 acres. Several development scenarios were investigated in 

regard to their impact on the water resources. Percent imperviousness ranged from 5% 

for existing land uses to 80% for developed. Runoff volumes were predicted to 

increase from 16.0 in/yr to 32.2 in/yr at 80% developed or 47% impervious. 

Briley, Wild & Associates, Inc. “Master Stormwater Drainage Plan, Area “A”, 

November 1984. Revised September, 1987. 

Four drainage basins (Bowlees Creek 9.9 square miles), Cedar Hammock Canal (9.1 

square miles), Pearce Drain (8.3 square miles), and the Palma Sola Drain (2.6 square 

miles) are included in study area “A.” Drainage area “A” is located along the coast and 

on the south side of the Manatee River. The report indicated that most of the primary 

drainage ways were inadequate to carry the 25-year flood flows without extensive 

property damage and many could not even convey a 5-year storm. As a result of 

channel inadequacy, many options were proposed to enhance drainage system 

capacity. Design criteria for the proposals required that the stormwater management 

systems control runoff from a 25-year frequency - 24-hour rainfall of 9.0 inches without 

causing flooding. Local shallow flooding would be allowed provided private property 

was not flooded. DABRO and a water surface profile program were used to compute 

flood elevations along the primary drainage system assuming a tailwater condition of 

3.0 feet. Some of the subbasin areas listed are not within the Manatee River 

watershed. 

Bowless Creek System includes the Airport Drain, Little Pittsburgh, Big 

Pittsburgh, and the Oneco Drain that discharge to Sarasota Bay. Numerous 

improvements were recommended to relieve flooding along the primary drainage 

system. 

Cedar Hammock System includes the East, West, and South Branches that 

drain to the Manatee River. Stormwater discharge from the DeSoto Plaza 

Shopping Mall was designed to utilize storage within the parking lot. Detention 

ponds and channel hardening were recommended to reduce flooding. 


April 26, 2001 4-9 


Pearce Drain System is a complete system and discharges to the Braden River. 

Recommendations were to increase the conveyance capacity of the primary 

drainage system. Desiltation basins were also recommended. 

Palma Sola System includes the Palma Sola Bay system and the Sarasota 

Drain. Part of the system discharges to Palma Bay and the remaining portion 

discharges to Sarasota Bay. Recommendations include increased conveyance 

under roadways. 

Various funding mechanisms were recommended to provide revenue to construct the 

flood mitigation components. In addition, stormwater regulations were proposed using 

a 25-year, 24-hour storm event as the design criteria. 

Briley, Wild & Associates, Inc. “Master Stormwater Drainage Plan, Area “B”, 

April, 1986. 

Eleven drainage basins are included in the study area “B.” Eight are located just west 

of the City of Palmetto and the three are just east of the City of Bradenton. The basins 

are: Carr Drain basin, Canal Road Drain basin, Big Chimney Drain basin, the Gamble 

Creek basin, Tampa Gap Drain, Government Hammock Drain basin, Slaughter Canal 

basin, McMullen Creek basin, Rattlesnake Slough basin, Cedar Creek basin, and the 

Sugarhouse Creek basin. Wares Creek, and the East Branch of Cedar Hammock that 

is within the City of Bradenton was also studied. In addition, about 150-square miles 

of the rural portion of the County located just east of the urban areas were studied 

along with the agricultural portion of the county. The report indicated that the urban 

and urbanizing basin conveyance systems could not contain the 25-year storm with 

many unable to convey the 5-year within channel banks. 

Two methods were presented for funding recommended conveyance system 

improvements: 1) establishment of drainage Districts or 2) a user fee based on 

equivalent residential units (ERU). Other regulatory matters included land and rightof-way 

acquisition to ensure proper maintenance. Desiltation basins were also 

proposed for water quality improvement. The design storm upon which the study 

alternatives are based is a 25-year, 24-hour storm with a cumulative volume of 9.0 

inches. 

Wares Creek Plan - included only drainage system conveyance improvements 

due to the urban nature of the watershed. No areas were available for creating 

detention facilities. 

Rural Basins (150-square miles) - include the following basins: 

1. Gamble Creek Basin 

2. Northwest (Frog Creek) Basin 

a. Wade Creek 

b. Buffalo Creek 

c. Cedar Drain 


April 26, 2001 4-10 


d. Cabbage Slough 

e. Frog Creek 

3. Mill Creek Basin 

4. Goddard Creek, Rye Branch and Sand Branch Basin 

5. Cypress Strand and Gates Creek Basin 

6. Northeastern Portion Lower Braden River Basin 

7. Upper Braden River Basin 

8. Cooper Creek Basin 

Agricultural Basins - The Manatee River was previously studied by HNTB, July, 

1981. A 9.5 inches rainfall was used for the critical storm event. 

Carr Drain - the management plan essentially called for an increase in 

conveyance 

Canal Road Drain - increased conveyance was recommended over the 

construction of detention ponds due to costs. 

Big Chimney Drain - due to the development of the basin, conveyance 

enhancement was recommended. Predicted flooding within the basin was quite 

extensive. 

Tampa Gap Drain - conveyance system improvements were recommended to 

reduce costs due to the extensive nature of the flooding and to reduce cost of 

remediation. 

McMullen Creek - did not flood under the 25-year, 24-hour storm event. 

Consequently, no stormwater improvements were recommended. 

Gamble Canal - basin was too far developed to practically use detention basins; 

therefore, conveyance system improvement was recommended. 

Government Hammock Drain - Increasing the size of road crossing conduits 

and channels was recommended to relieve flooding within the basin. 

Slaughter Canal Basin - all flows could be contained within the banks of the 

system. Consequently, no stormwater improvements were recommended. 

Rattlesnake Slough - Since the watershed has not been developed, the 

recommendation was to delineate the floodplain where no future construction 

would be allowed. 

Cedar Creek - can convey the 25-year, 24-hour storm event. No improvements 

were recommended. 


April 26, 2001 4-11 


Sugarhouse Creek - floodplain management was the recommendation for this 

basin. General consideration was given for pollutant loadings from non-point 

sources, and nutrients. Sediment transport was considered the largest 

contributor. Therefore, areas of high velocity where scour is a problem were 

recommended for excavation and construction of siltation basins as a way to 

remove suspended solids. 

4.5.2 USGS Gages - Flow Data 

02299950 “Manatee River Near Myakka Head,” latitude and longitude (27-28- 

24/82-12-41), drainage area 65.3 sq. mi., initiated in 1966. 

02300000 “Manatee River near Bradenton,” Removed in March 1965 due to 

construction of Manatee Reservoir. 

02300032 “Braden River Near Lorraine, ” latitude and longitude (27-25-20/82- 

25-00), drainage area 25.8 sq. mi., initiated in 1988. 

02300034 “Hickory Hammock Creek Near Lorraine, ” tributary to Braden River, 

latitude and longitude (27-25-18/82-25-56), drainage area 2.4 sq. mi., initiated in 

1988 

023000355 “Cooper Creek at University Parkway Near Sarasota,” tributary to 

Braden River, latitude and longitude (27-23-18/82-27-35), drainage area 9.33 

sq. mi., initiated in 1988. 

02300037 “Cedar Creek Near Sarasota,” tributary to Braden River, latitude and 

longitude (27-24-51/82-28-53), drainage area 0.94 sq. mi., initiated in 1988. 

02300038 “Rattlesnake Slough Near Sarasota,” tributary to Braden River, 

latitude and longitude (27-25-24/82-29-25), contributing drainage area 3.78 sq. 

mi., initiated in 1988. 

02300039 “Nonsense Creek Near Bradenton,” tributary to Braden River, latitude 

and longitude (27-26-04/82-28-04), contributing drainage area 1.14 sq. mi., 

initiated in 1988. 

02300042 “Ward Lake Outfall near Bradenton,” major portion of Braden River 

watershed, latitude and longitude (27-26-28/82-29-16), contributing drainage 

area 59.5 sq. mi., initiated in 1992. 

4.6 Regulator/Authority and Special Rules 

Chapter 40D-4, F.A.C., provides the basis for surface runoff quantity and quality 

control by the Southwest Florida Water Management District (SWFWMD). Discharges 


April 26, 2001 4-12 


to the Manatee and Braden Rivers fall under the general criteria that governs most 

surface water discharges within the District. In addition to District requirements, 

Manatee County further limits peak release rates based on the flood conditions within 

the watershed. FDEP regulates dredging and filling in wetlands, although some of this 

function has been delegated to the District. 

Guidelines exist for releases from the Lake Manatee Reservoir during flood conditions 

in the Upper Manatee River Watershed. Regulation of the releases provide some 

downstream protection from flood damage while maintaining the integrity of the 

impoundment by the prevention of overtopping. Operational guidelines were mandated 

by the USACE. 

4.6.1 SWFWMD Regulations 

Chapter 40D-4’s Basis of Review specifies that post-development peak discharge rates 

for new development should not exceed pre-development peak discharge rates for the 

25-year, 24 hour storm event. In closed watersheds, i.e., those that do not have a 

surface outfall up to and including the 100-year, 24-hour event, post-development 

discharge volumes must not exceed pre-development discharge volumes for the 100- 

year 24-hour event. However, most if not all of the basins within Manatee River 

Watershed exhibit a surface water outfall feature. 

In addition to regulating discharge, the District restricts floodplain encroachment. 

District regulations require compensating storage for areas when fill is placed with the 

100-year floodplain. It is recognized that floodplain storage provides a significant role 

in reducing peak flows and levels. Rules also stipulate that activities affecting 

floodplains and floodways will not cause adverse impacts, i.e., increased flooding. For 

example, increasing the size of a conveyance structure in a upstream reach of a stream 

to reduce flooding in an area is usually prohibited because the problem is typically 

transferred downstream. Technical guidelines are available that detail procedures to 

analyze and minimize impacts from activities in a floodplain. 

4.6.2 County Regulations 

Chapter nine of The Manatee County Comprehensive Plan (1998) contains information 

concerning stormwater quality and quantity guidelines for proposed developments. 

Manatee County stipulates that the primary surface water structures should provide a 

level of service capable of conveying runoff from a 25-year, 24-hour storm event. To 

achieve this goal, Manatee County has recently undertaken a project to identify the 25- 

year floodplains for 24 major subbasins located within the developing basins of the 

county. The ultimate goal is to maintain a natural floodway. Encroachments into these 

25-year floodplain are to be limited so that the conveyance ways can be preserved. 

This is in addition to the District’s regulation which stipulates that no adverse impacts 

or reduction in storage within the 100-year floodplains can take place. The 

comprehensive plan stipulates that conveyance structures within the development shall 


April 26, 2001 4-13 


provide a level of service based on a 10-year critical duration storm. Critical durations 

for small basins are typically equal to the time of concentration of the basin. The plan 

also prescribes design considerations for the construction of retention/detention 

facilities. They are to be safe, aesthetically pleasing, and promote wildlife habitat. 

Besides the guidelines provided in the Manatee County Comprehensive Plan, the 

Manatee County Public Works Department Engineering Division has developed a 

manual entitled, “Stormwater Management Design Manual,” dated December 11, 1990. 

Essentially the manual sets forth the guidelines and methodologies to be used for the 

design of water conveyance systems in more detail than the comprehensive plan. 

Basically the 25-year, 24-hour storm design criteria is to be followed unless the 

proposed system is located within a know flooding area or in a restrictive outfall setting. 

If these conditions exist, then the system design criteria is more stringent. For designs 

located in the Evers and the Lake Manatee watersheds, an additional 50% increase in 

water quality treatment is required. Facility ownership and maintenance guidelines are 

also provided within the manual. 

4.6.3 Municipal Regulations 

Typically municipalities such as the Cities of Bradenton and Palmetto follow District 

regulations concerning stormwater management. 

4.6.4 U. S. Army Corps of Engineers (USACE) Regulations 

Typically the Army Corps of Engineers regulates dredge and fill within what is 

navigable water ways. They have jurisdiction over certain wetlands. The USACE 

regulates the construction of dams and levees within “Waters of the U.S.” The 

Manatee and Braden Rivers are considered CORPS projects. Specifically, the flood 

operational aspects of the Manatee Reservoir required USACE approval. 

4.6.5 Florida Department of Environmental Protection Regulations 

The Florida Department of Environmental Protection (FDEP) regulates the placement 

or removal of fill in wetlands and for some projects under its dredge-and-fill permitting. 

FDEP also serves as a permitting agency for erosion or flood control projects directly 

implemented by the Southwest Florida Water Management District. Typically, joint 

applications are filed with the USACE and FDEP when requesting a dredge and fill 

permit in “Waters of the State or U.S.” However, most of the dredge and fill permitting 

in isolated wetlands has been delegated to the water management districts. Although 

these rules do not specifically relate to water quantities, they do have an indirect 

influence on streamflow rates and flood levels due to the restrictions that are imposed. 

FDEP policies attempt to maintain the functions of the natural systems. 


April 26, 2001 4-14 


4.7 Land Acquisition Program 

Several agencies have land-acquisition programs that operate within the Manatee 

River watershed. These programs include the Department of Environmental 

Protection’s Conservation and Recreational Lands (CARL) program, the District’s Save 

Our Rivers (SOR) program and Manatee County’s acquisition program. For example, 

Manatee County opted to buy most of the mining property within the Lake Manatee 

River watershed to protect their water supply. As a result, several thousand acres are 

now owned by governmental agencies that protect the environmental resources of the 

watershed. Manatee County has also purchased areas for water supply development. 

Typically, these programs emphasize preservation of natural systems and 

enhancement/preservation of water quality. However, a side benefit is often obtained 

since the lands purchased often include flood-prone wetland areas. Acquisition serves 

to prevent development in these natural flood storage areas. As a result, future 

drainage modifications or difficult management decisions concerning regulation of flood 

levels within the natural flood storage areas are avoided. 

4.8 Other Governmental Activities 

Manatee County and the SWFWMD have a system for logging in flood complaints. 

Identifying the location of the flooding helps direct future efforts toward flood relief 

projects and Stormwater Master Planning. The District tracks and records flood 

complaints by section, township, and range. Complaints are physically assessed to 

determine if there is a violation of District rules and, if so, actions are taken to correct 

the situation. Manatee County logs in flood complaints by the person’s last name and 

street address. The FDOT keeps record of high water marks related to road design. 

Appraisals of the magnitude and duration of the flooding can be made to determine 

whether a cost effective solution can be derived. 

4.9 Emergency Management 

Many agencies and organizations are involved in emergency management, such as the 

Federal Emergency Management Agency, State Agencies, Regional Planning 

Councils, County and City governments, and the red cross. Hurricanes, tornadoes, and 

flooding situations usually require assistance from these agencies. Natural disasters 

require strategies such as evacuation planning and implementation of other mitigation 

measures. Services required in a natural disaster situation include the establishment 

of temporary housing, delivery of food and water, rescue operations, emergency 

medical services, flood control system operation, damage control and assessment, 

flood insurance compensation, delivery of federal aid, flood hazard mitigation, repair 

and or replacement of public infrastructure, and debris removal within streams and 

other waterways. Properly targeted building and land use codes and regulations can 

minimize these requirements. 


April 26, 2001 4-15 


4.10 General Flood Issues 

Natural fluctuations of surface water elevations occur on the landscape of uplands and 

water features within the watershed boundaries of the Manatee and Braden Rivers. The 

watershed’s response to these fluctuations played a role in shaping the natural 

systems, their characteristics, function, and interactions. Through time, conditions 

occur within the watershed in which the surface water elevations are higher than 

normal and water overflows onto areas of dry land. This flooding of dry land occurs as 

a response to the dynamics of the hydrologic cycle. The areas subject to flooding will 

be defined as flood prone areas for this discussion. The issue at hand is to understand 

the function of the flood prone areas and to provide protection from damages when 

flood conditions occur within the watershed. The District’s water management goal for 

flood protection is, "To minimize the potential for damage from floods by protecting and 

restoring the natural water storage, and conveyance functions of the flood prone areas. 

The District shall give preference wherever possible to non-structural surface water 

management methods." 

Analysis of existing studies, current SWFWMD activities, and discussions with county 

staff reveals a multiplicity of issues within the Manatee River Watershed. In general, it 

appears that the attenuation and conveyance capability provided in most developed 

areas are inadequate to meet the expected Level of Service (LOS) for flood control. 

The Level of Service is the watershed’s water level response to a storm event which is 

typically related to a specific return interval, in this case the 100-year. In some 

instances, the Level Of Service provided under the “natural setting” may not have been 

properly defined which resulted in encroachment into the existing floodplain. 

Encroachments into the floodplain create a condition in which storage and/or 

conveyance capacity are diminished exacerbating the situation. These encroachments 

can result in increased flood levels upstream or downstream of the impacted area. In 

addition to encroachments, developments can increase the amount of discharge to an 

area through drainage system enhancement and increased impervious area. Increases 

in impervious areas are generated from the construction of impenetrable surfaces such 

as roadways, buildings, parking lots, etc. 

Tables 4.1 and 4.2 provide a summary of the estimated areas of existing and future 

urban uses within the FEMA 100-year designated flood hazard zones. Existing urban 

land uses within the FEMA flood zones are based on 1990 aerial photography for the 

Manatee River watershed while future urban land uses within the FEMA flood zone are 

based on information provided by the Southwest Florida Regional Planning Council 

projected for the year 2010. The existing urban area within the 100-year flood zone is 

approximately 4,000 acres. In the future, it is expected that this area will increase by 

an additional 14,000 acres for a total of 18,000 acres. For this reason, flooding and 

continued development within the floodplain is a concern. Nevertheless, Manatee 

County Zoning restrictions should ensure that finished floor elevations of new homes 

are above the designated flood elevation. 


April 26, 2001 4-16 


Total area within the Manatee River watershed that is within the FEMA 100-year is 

about 31,000 acres. The total area within flood zone ‘C’ (area of minimal flooding) is 

188,000 acres. However, comparisons between wetland acreage and the amount of 

acreage designated as a FEMA flood prone area suggests that the level of detail in 

certain areas is lacking. Acreage for wetland areas are significantly greater than the 

acreage of the flood zone areas which should automatically be included within the flood 

zones. 

Table 4-1: 

1990 Urban Land Use (Existing) Within the FEMA 100-Year Flood 

Zone 

Land Use Classification 

Acreage 

Residential 5 Units/Acre 1,427.22 

Commercial and Services 243.97 

Industrial 40.27 

Extractive 16.62 

Institutional 95.36 

Recreational 128.04 

Open Land 684.29 

Total: 4,044.76 

Table 4-2: Urban Future Land Use Within FEMA 100-Year Flood Zone 

Land Use Classification 

Acreage 

Estates (Low Density Residential) 1,171.47 

Single Family (Medium Density Residential 12,265.07 

Multi-Family (High Density Residential) 3,360.76 

Commercial 773.45 

Industrial 304.43 

Mining 0.00 

Total: 17,875.18 


April 26, 2001 4-17 


4.11 Specific Flood Issues within the Manatee River Watershed 

It has become apparent that flood protection has become a complex process in that a 

holistic approach to water management is now being pursued from a state and federal 

level. Natural system preservation, water supply, water quality, and flood protection 

considerations are being integrated in order to construct a comprehensive surface 

water management system. As a result, more information and sophisticated modeling 

are required to make good projections of flood levels based on the probabilistic 

variation of rainfall. The purpose of the following sections is to identify issues 

associated with flood protection so that action plan strategies can be developed. 

Previous review of the stormwater management master plans prepared for the various 

tributary watersheds revealed that restrictions (bridges and culverts) placed in natural 

streams are a significant factor in increasing the flood potential within a basin. 

Typically, the stormwater management plans recommend that the conveyance 

structures used to allow passage over a stream be upsized to reduce water surface 

elevations upstream. In other situations, increasing the conveyance capacity of a 

channel or outright purchase of homes was recommended. Purchase of homes was 

pursued for the river section below the Manatee River Dam. These last two situations 

suggest that residential structures were originally within a floodplain. Thus, for the 

primary conveyance ways of the Manatee River, increased vulnerability to floods can 

result from either building within tidal surge areas of the river or within the riverine 

floodplain itself. 

Issue #1a: Data Management 

Background: Data management includes the collection, maintenance, update/revision 

and retrieval of the information required to understand the systems that influence the 

water resources of a watershed. Data can be used in a variety of ways to produce 

information that defines the flood prone areas. Watershed characteristics are 

constantly changing, therefore, data must be updated frequently to accurately 

represent the current state of the watershed. 

The ability of the District, private consultants, Federal, State, or Local Governments to 

complete accurate Flood Prone Area analyses is dependent upon the quality of the 

data available. Limitations on the collection of quality data include the cost of data 

acquisition, physical constraints, and lack of knowledge concerning what data is 

available and where it is located. Thus, a database standard should be developed so 

that a central repository of watershed information can be developed and updated. 

Strategy: Standardize hydrologic/hydraulic and flood protection data collection and 

management. 

Actions: 


April 26, 2001 4-18 


1. Develop a standardized data management system that provides the information 

required to define the flood prone areas (hydrologic/hydraulic information and 

flood levels). 

Responsible Parties: Federal Emergency Management Agency (FEMA), the 

Southwest Florida Water Management District (SWFWMD), and Manatee 

County 

Estimated Cost: Included in the Cost of Performing the Floodplain Analysis. 

Time-Frame: Standard has already been developed. 

2. Provide the requirements necessary, in an ARC/INFO based GIS format, to 

allow the transfer and formulation of input and output data from numerical 

models. This will support further data development for other predictive models 

(i.e., water quantity, water quality, ground water, natural systems). It will also 

provide access to the data and modeling results for surface water regulation 

within the watershed. 

Responsible Parties: The SWFWMD, FEMA, Manatee County, Modeling 

Vendors. 

Estimated Cost: $250,000 

Time-Frame: 2 to 3 Years. 

3. Encourage the development of data transfer tools by the developers of 

stormwater management software. The goal is to have software with the 

capability to transfer the input data and output results to a universally acceptable 

standard or to translate the information to data formats used by other stormwater 

management software and GIS. 

Responsible Parties: FEMA, SWFWMD, Manatee County, and Modeling 

Vendors. 

Estimated Cost: Included in the purchase price of the software. 


4. Use of data management tools to update the database through the SWFWMD’s 

regulatory process by requiring permit (ERP) submittals to include data in widely 

accepted format and data standard. 

Responsible Parties: The SWFWMD, FEMA, Manatee County, Modeling 

Vendors. 

Estimated Cost: Estimated $30,000 

Time-Frame: 2 to 3 Years. 

5. Perform aerial mapping with contour information (paper and digital formats) for 

areas in the watershed that have no such information or outdated information. 

This could also be achieved using new technologies such as LIDAR. 

Responsible Parties: The SWFWMD and Manatee County. 

Estimated Cost: Estimated between $3,000 to $7,000 per square mile. 



April 26, 2001 4-19 


6. Promote cooperative agreements to build data collection responsibilities based 

on need and the capabilities of the agency (FEMA, SWFWMD, Counties, Cities, 

private, etc.). 

Sub-issue #1b: Collating of Existing Watershed Information 

Background: Available flood information is held by many organizations and 

individuals. Consolidation of available material into a centralized flood information 

database, specific to the Manatee and Braden River watersheds would greatly improve 

the usefulness of the data. It would make the data readily accessible, permit rigorous 

quality control, facilitate updating the data, and would allow consistency in its 

application and use. Such a database could be implemented via the District’s GIS 

system. This would require coordination between various organizations, and use of 

standardized reporting methods. 

Although copies of most of the flood prone area studies are readily available, their 

format requires interpretation of flood information at various cross-sections to 

determine flood prone area boundaries projected in the studies. Delineation of flood 

prone area boundaries on aerial maps, and possibly within GIS systems, would provide 

a useful tool for analyses of water quantity issues. Also, associated 

hydrologic/hydraulic information should be processed and incorporated into the 

database. 

Strategy: Develop a GIS database of current floodplain information for the Manatee 

River watershed. 

Actions: 

1. Delineate boundaries of existing flood prone area studies (on GIS from 1" = 200' 

aerials). 

2. Identify the methods used, level of detail and goals of each study area. 

3. Identify areas that were not adequately studied in existing studies. 

4. Check the accuracy of completed studies with the actual physical conditions of 

the study area. 

5. Identify areas of flooding impacted by storm surge. 

Responsible Parties: The SWFWMD and Manatee County 

Estimated Cost: $200 to $300 per square mile. 

Time-Frame: As scheduled. 


April 26, 2001 4-20 


Issue #2: Flood Prone Area Analysis 

Background: The methods used in flood prone area analysis vary from statistical 

analysis of measured physical data of past conditions to the use of mathematical 

algorithms in computer programs (models). Models predict a simulated response by 

the watershed, based upon physical data, and assumptions of the watershed 

characteristics. The amount and quality of data used for input determines the level of 

detail provided for the analysis. The goals of the analysis will establish the detail 

required to provide reasonable projections of the water surface elevations, conveyance, 

and floodplain area within the watershed. The modeling process requires verification of 

the data used in the computer program. The predicted results should be within the 

realm of physical possibilities and represent the physical conditions that would occur 

during a flood event. During the modeling process additional data may be needed to 

accurately represent the response of the physical system. The simulation results 

should represent the response of the watershed to a particular rainfall event and 

hydrologic setting when a sufficient level of detail is applied. 

Strategy: Standardize methods and level of detail required for flood prone area 

analysis. 

Actions: 

1. District standards should be established for the methods used to complete a 

flood prone area study. 

2. District minimum standards should be established for the level of detail required 

in reporting the findings of a flood prone area analysis. In addition, a 

standardized format (electronic and paper form) should be established for the 

reported findings (Issue #1). 

3. Standardize study and data collection methods should be made available to the 

municipalities and counties in the watershed for distribution to contractors when 

hiring outside consultants to perform flood and storm water management 

studies. 


Estimated Cost: Included in the cost for performing the flood prone analysis. It is 

concluded that the use of the standard will reduce analysis costs due to the 

ability to perform automated processing. 

Time-Frame: As scheduled. 

Issue #3a: 

Infrastructure Management Policies, Regulation, and Programs 

Background: Urban development in a pristine watershed changes its runoff 

characteristics. Increases in peak discharge rates and runoff volumes typically occur 


April 26, 2001 4-21 


as a watershed is developed. To counter these effects, the SWFWMD and Manatee 

County have dictated that the post development peak runoff rates can be no greater 

than the pre development runoff rates. This is accomplished by creating attenuation 

basins that temporary store runoff excesses and regulate discharge from the site. 

However, total volumetric increases from a development site still occur. These 

regulatory policies potentially extend the post runoff hydrograph durations beyond the 

duration of the pre existing hydrograph thus affecting tailwater and/or headwater 

conditions for adjacent tributary areas. If enough of these independent development 

sites exist, a cumulative impact of sufficient magnitude could be generated that 

increases flood levels. This is especially true if the time of concentration for the 

watershed is greater than 24 hours. 

Use of several different strategies can help address the problem of increased runoff 

volumes. Analysis of various duration rainfall events for a specific return period can 

identify which event results in the greatest amount of flooding. Florida Department of 

Transportation (FDOT) regulations require a similar analysis, known as the "critical 

event" analysis (FDOT, 1987). In addition, modification of current regulations can 

require more or less detention for slower or quicker release of runoff to avoid peaks 

flows and stages in the receiving water. Reuse of storm water for irrigation purposes is 

potentially another method for reducing runoff volumes. If built on an appropriately 

large scale, the volume available in storm water reuse holding ponds could also 

provide flood protection. 

Strategy: Develop analysis protocol that contributes to the minimization of impacts 

beyond peak flows. 

Actions: 

1. Require modeling that establishes tailwater conditions and the potential effects 

of the new stormwater system on upstream and downstream stages. Peak 

discharge and timing analyses should be performed to minimize impacts on 

water levels in the receiving waterbody or stream. 

2. Permit applications should require "critical event" analysis. 

3. Promote projects that increase storage volume in flood prone areas while 

maintain existing conveyance ways. 

4. Develop regional models that can evaluate cumulative impacts associated with 

land use changes within the watershed. 


Estimated Cost: $15,000 to $24,000 per square mile. 

Time-Frame: As project scheduling and budgets allow. 


April 26, 2001 4-22 


Sub-issue #3b: Inaccurate Flood Level Information 

Background: Inadequate regulations are created by a lack of information, lack of 

political support, or errors made in identifying flood prone areas. Land alterations, 

which limit or destroy the function of the flood prone areas, have been allowed because 

the flood prone areas were not properly illustrated on Flood Insurance Rate Maps 

(FIRM) administer by The Federal Emergency Management Agency (FEMA). Storage 

of floodwaters occurs on most properties in Florida, especially where jurisdictional 

wetlands exists. Regulations, now enforced by the District and county governments, 

require that storage in these areas be included in the existing condition analysis (predevelopment) 

of the site’s runoff characteristics. Typically, the 100-year 24-hour storm 

event is evaluated to establish the existing condition floodplain for a site. 

Nevertheless, certain land use alterations are not regulated which provides a means 

whereby the function of the floodplain can be altered. These are typically low density, 

rural developments and some agricultural operations that do not required an 

Environment Resource Permit. As a result diversions, fill, and restrictions can be 

constructed within the floodplain that alter its function. Thus a sufficient infrastructure 

inventory and identification of the floodplains can help prevent this from occurring. 

Flood levels for some areas of the Manatee River Watershed are based on the 

combination of USGS regional regression equations and the step-backwater model 

HEC-2. USGS equations are used to predict the peak discharge rates for a 

contributing area while the HEC-2 model is used to predict the resultant water surface 

elevations within the conveyance ways. USGS regression equations are developed 

from gage station data and other watershed information that are sometimes 

extrapolated to other areas within the region where information is lacking. Regression 

results that are extrapolated to other areas are ballpark predictions and therefore tend 

to have large predictive errors. These prediction errors may be associated with 

unknown hydraulic features of the basin, incomplete knowledge of the rainfall volumes 

and distributions, and varying antecedent moisture conditions, storage, etc. 

Strategy: Watershed analysis should be performed using detailed modeling protocol. 

This strategy will provide the development of the conveyance system inventory and 

proper identification of floodplains. 

Actions: 

1. Development of regional models that provide an inventory of the flood prone 

areas along with associated infrastructure information and location. 

2. Ensure that design regulations are enforced. A major component of the 

stormwater regulation is compensation for development in flood prone areas. 

Efforts should be made to ensure that lands used for compensating storage are 


April 26, 2001 4-23 


available when needed, i.e., other uses of the storage areas should not interfere 

with the designed flooding of the site. 

3. Conservative determinations of seasonal high groundwater elevations should be 

used when determining compensating storage for encroachments into the 

floodplain. 

4. During permitting, cumulative impacts should be considered so that 

compensation can be made for increases in runoff volume within the area. This 

action may require alteration of the 40D-4 regulations. 

5. Periodic inspection of stormwater management systems should be performed to 

ensure the integrity of impoundments, embankments and other hydraulic 

components of the surface water system. 

Sub-issue #3c: Use of Surface Water Systems for Water Supply and Flood 

Protection 

Background: Water supply is a critical concern in the Manatee County area. For 

example, the Ever’s Reservoir has been expanded to provide additional water for the 

City of Bradenton while the county is now looking at various options for expanding the 

Manatee Reservoir. As a result, policies were adopted in the 1998 revision to the 

Manatee County Comprehensive Plan that require the use of surface or other 

alternative water sources for non potable demands such as lawn irrigation. This 

strategy was a recommendation in the Evers Reservoir Report (Wanielista, 1989) so 

that the runoff characteristics of the watershed would be maintained. Surface waters 

were to be pumped back up onto the watershed to maintain the base and interflow 

characteristics of the watershed under developed conditions. This would provide a 

constant source of inflow to the Evers Reservoir. In order to maximize the use these 

sources, water levels are typically held higher in detention ponds which could create a 

conflict with flood control. The current comprehensive plan requirements for alternative 

supply development apply county-wide and do not address these alterations to the 

surface water systems. 

Strategy: Develop guidelines that consider the dual use of flood control ponds. 

Actions: 

1. Develop an inventory of detention ponds that are also being used as an 

alternative water supply source. Make comparisons regarding dual use systems 

within known flooding areas. 

2. Permitting guidelines should be developed for the design of dual use ponds in 

cooperation with Manatee County and Municipalities. Water supply storage 

should be considered in conjunction with the storage necessary for flood control. 


April 26, 2001 4-24 


In addition, consider increases in the antecedent moisture condition resulting 

from the reuse of surface water for irrigation. 

3. Periodic inspections of the surface water systems should be made to ensure that 

the hydraulic configurations have not been altered. Field observations have 

indicated that temporary blocks are sometimes used to maintain levels within the 

ponds for aesthetic purposes which could create a potential flood situation. 

Responsible Parties: Local Municipalities, Manatee County, and Home Owner’s 

Associations. 

Estimated Cost: Unknown 

Time-Frame: Ongoing 

4. Develop a Watershed Management Program for the Braden River Watershed. 

The management program would assess the effects of stormwater management 

policy on water supply, surface water quality, and flood protection. The first 

phase of the program would include a watershed evaluation that provides an 

inventory of the stormwater infrastructure and watershed topology. The last 

phase would include the acquisition of survey information of the stormwater 

infrastructure, floodplain analysis, development of FEMA floodplains for Federal 

Insurance Rate purposes, and a surface water capacity assessment. Data 

developed from the floodplain analysis would be used in the surface water 

capacity assessment. 

Responsible Parties: Southwest Florida Water Management District, Manatee 

County, Sarasota County, Braden River Utilities, and the City of Bradenton. 

Estimated Cost: $1 Million 

Time-Frame: Two Years 

Sub-issue #3d: Proposed Development Plans May Be Different from Actual 

Construction 

Background: The level of service provided within a development is based upon 

projected land use alterations, and densities. The major item that effects the volume of 

runoff generated from a development is the amount of impervious area created. Design 

engineers make assumptions as to the square footage of the homes that will be built 

and the type of amenities that will be added such as decks, swimming pools, driveways, 

etc. Assumptions are also made as to whether the impervious areas are directly 

connected to the surface water management system or whether the runoff is allowed to 

pass over pervious areas such as lawns where a certain amount of the runoff will 

infiltrate. Under estimation of impervious area leads to under estimation of the runoff. 

For example, if the development is designed with an assumed residential lot with a 

2,000 square foot impervious area and the actual constructed amount is 2,700 square 

feet, a significant increase in runoff volume will occur from that originally projected. As 

a result, the level of service for flood protection could be decreased. 


April 26, 2001 4-25 


Strategy: Statistical comparisons should be made between the design percent 

imperviousness and the actual constructed imperviousness. 

Actions: 

1. Random tax assessor information of lots from existing developments should be 

made from field observations and FDOT aerial maps. Univariate statistics 

should be provided for the percent impervious and then compared to the original 

design estimates. 

2. If significant variations exist between the proposed and actual percent 

imperviousness, then the collected data can be used to develop new guidelines 

for design purposes. 

3. Multi-phased developments can also be checked for variations between 

proposed and constructed percent impervious areas. If initial phases of the 

development indicate significant variations from that original proposed, 

modifications in the surface water system for subsequent phases could be 

pursued. It is possible that the modifications in the later phases can be used to 

offset impacts from the earlier phases. 

4. Pursue regulatory changes, if necessary, to refine stormwater pond permitting 

consistent with study results. 

Responsible Parties: Manatee County 

Estimated Cost: $20,000 

Time-Frame: 6 months 

Sub-issue #3e: 

Use of basin specific criteria to address unique 

circumstances. 

Background: Establishment of basin specific criteria identifies the LOS provided by 

the existing surface water system. Hydrologic and hydraulic features of the watershed 

are identified prior to establishing specific criteria so that better management decisions 

concerning development activities can be promoted. For example, in the Braden River 

watershed, recommendations were made by Wanielista (1987) concerning the 

maintenance of the baseflow and interflow characteristics of the watershed. This 

aspect of the watershed was considered important regarding the long-term viability of 

the water supply reservoir. Basin specific criteria can be expanded to address all 

aspects of the watershed, i.e., water supply, water quality, habitat restoration, etc. 

Basin specific criteria can also address unique circumstances for an area similar to that 

of Flatford Swamp. Cooperative solutions can be devised which could eliminate the 

need for multiple layers of regulation. 

Strategy: Impact-based solutions should be developed for each basin to address a 

variety of watershed issues. 


April 26, 2001 4-26 


Actions: 

1. Require flood prone area analysis for specific basins that are under 

development pressure. The analysis would identify existing runoff volumes and 

recommended LOS. 

2. Explore the possibility of modifying regulatory criteria to limit discharge volumes 

through enhanced infiltration. Enhanced infiltration areas would be used to 

offset increases in runoff due to increases in impervious area. 

3. Encourage alternatives to impervious surfaces such as porous pavement. 

Benefits should be presented and incentives provided. 

Responsible Parties: Manatee County and the SWFWMD. 

Estimated Cost: Unknown. 


Sub-issue #3f: 

Measurement of regulatory approaches to flood control. 

Background: Effective permitting includes monitoring and data collection to detect 

whether or not regulations are achieving their intended results. Site inspection efforts 

should include determinations of whether or not floodplain encroachment is greater 

than permitted. With respect to data collection and analysis, one area of focus should 

be a method to determine whether or not water surface elevations are increasing over 

time. Manatee County and the USGS have established monitoring sites throughout the 

county. The data from these monitoring sites currently suggests that under current 

water quantity regulations developments are causing increased flooding. 

Strategy: Evaluate and enhance the existing surface water monitoring network to 

include monitoring of rainfall, water surface elevations, and flows. 

Actions: 

1. Evaluate the existing data collection network to determine its accuracy and 

reliability. 

2. Set up test watersheds to determine the effectiveness of regulatory 

management strategies. Manatee County and the District have numerous 

gaging stations throughout the Manatee and Braden River Watersheds. 

3. Perform periodic inventories to document land use changes within the 

watershed. The information should be developed on a GIS platform. The 

District generates this database on 5-year intervals. 


April 26, 2001 4-27 


Responsible Agencies: The SWFWMD, Manatee County, and USGS. 

Estimated Cost: $3,400 per square mile per year for monitoring a tributary area.. 


Sub-issue #3g: 

Conflicts with land use planning and water management 

Background: Current land use regulations within Manatee County allow development 

to occur within the 100-year floodplain. Generally, finished floor slabs are constructed 

above the 100-year flood level to prevent the incidence of structural damage as a result 

of flooding. Nevertheless, nuisance flooding of yards, septic systems and roadways 

still occur. Recent efforts have been made by Manatee County to provide more 

protection of the 100-year floodplains by restricting development within the 25-year 

floodplains in order to maintain the primary conveyance ways. Natural attenuation 

helps prevent the deterioration of estuaries by dampening the peak discharges that 

induce large salinity variations. Development within floodplains tends to decrease the 

amount of natural storage necessary for peak discharge reduction. The reduction of 

natural storage occurs through the installation of fill within the floodplains which in turn 

causes increases in flood levels. 

As more and more development occurs within a floodplain, political pressure is 

heightened to alleviate the flooding of yards, roadways, etc. Since most of the more 

elevated portions of the floodplain are now occupied by development, it becomes 

difficult to devise a mitigation plan that reduces flood levels while minimizing adverse 

water quality and environmental effects. As a result, remedies can involve costly 

improvements to the conveyance system. Purchase of homes is an option that is 

difficult to implement due to the high cost of the structures and the lack of willing 

sellers. 

The home rule authority of cities and counties within the watershed, and the local 

decisions about the use of land that derive from this authority, have important 

ramifications for water management. This is particularly true of flood-prone areas. 

Flooding problems occur where these natural areas are developed for residential or 

commercial use. A cooperative relationship is needed to link management of land and 

water resources to minimize flood damages and the loss of natural flood storage areas. 

Manatee County is actively involved in their process. 

Strategy: Better linkage between watershed management and land use planning. 

Actions: 

1. Encourage local governments to established levels of service for current 

(present) and targeted (built-out) conditions for the watershed. Infrastructure 

capabilities for flood protection should be evaluated by methods developed by 

the Stormwater Level of Service (LOS) Conventions Committee. 


April 26, 2001 4-28 


2. Assist local governments in using LOS criteria in their comprehensive plans to 

measure the watershed’s current flood management capacity. Within the next 

year, all Florida jurisdictions must develop LOS criteria in their local mitigation 

strategy. 

3. Cooperate with FDOT and local governments on the design of roads. The roads 

should be designed to meet floodplain LOS. For those that do not meet the 

specified LOS, warning signs could be provided to alert drivers to flooding 

conditions. 

4. Support legislation that requires transfer deeds or other real estate documents to 

identify lands within a floodplain. 

5. Limitations should be imposed on flood insurance claims for repetitive flood 

damage in order to reduce premiums. 

6. Determine and establish appropriate setbacks from riparian systems for any 

structure, i.e., landward of 100-yr. floodplain, or some distance from 10-yr. 

floodplain or wetland boundary. State agencies need to work with local 

governments to enforce setbacks. 

7. Lobby local and county governments to change land use plans to limit densities 

in floodplains. A question is raised in regards to what is an acceptable density. 

8. Encourage nonstructural land uses (i.e., agricultural, recreational corridors) in 

floodplains that minimize alterations to the natural storage. 

9. Encourage conservation easements, green ways, efficient use of the required 

stormwater management storage, and placement of mitigation areas within 

existing flood prone areas. 

10. Work with local governments to encourage clustering of developments outside 

the floodplain. Also local governments should encourage cluster developments 

inside the floodplain if no other lands are available outside the floodplain. This 

encourages less infrastructure, less impervious surface, and the preservation of 

natural vegetation. 

Responsible Parties: The SWFWMD, Manatee County, FEMA, and the State of 


Estimated Cost: Is based on the size of the watershed area. 



April 26, 2001 4-29 


Issue #4: 

Rainfall Frequency and Duration Analysis 

Background: Flooding in the Manatee County area may have been the result of 

rainfall volumes and durations in excess of the current design standards. Manatee 

County current standards use a 25-year, 24-hour storm volume of around 8.0 inches 

and a 100-year, 24-hour volume of around 10.0 inches for establishing peak 

discharges and peak elevations. In fact, Sarasota County has increased its design 

storm from the 25-year pre- and post- to a 100-year pre- and post- for peak discharge 

predictions because of repetitive flooding in Sarasota County. Sarasota’s regulations 

are evidence that the current design standards in Manatee County for rainfall volumes 

and durations may not be sufficient to protect structures from flood damage. 

Strategy: Perform analyses of the rainfall stations located within the vicinity of the 

Manatee River watershed and calibrate existing Doppler radar information. 

Actions: 

1. Statistical analyses of rainfall stations within the area should be performed to 

determine intensities, durations, and return frequencies for large events. 

2. Rainfall events should be matched with periods of known flooding to better 

define the causal factors. Such factors include at a minimum spatial and 

temporal distributions of rainfall, initial flows, and initial water surface elevations. 

3. Once a causal relationship between rainfall and flooding conditions has been 

established, a revised rainfall distribution and volume should be developed that 

better suits the hydrologic setting of the watershed. 


Estimated Cost: $60,000 for the complete CWM area. 

Time-Frame: 1-year. 

Issue #5: 

Ownership, responsibility, maintenance, and operation of flood 

management systems. 

Background: The existing system is a melange of natural and manmade systems. A 

major factor in ensuring that an acceptable level of service is provided is to keep 

channels and conveyance ways clear of sediment, debris, and excessive aquatic 

growth. Siltation of channels decreases the cross sectional flow area while debris and 

aquatic growth create resistance to flow. Erosion from agricultural areas is of particular 

concern due to the removal of stabilizing vegetation. Under these conditions, intense 

storm events can generate sufficient velocities to erode the soil surface, transporting 

huge volumes of sediment to receiving streams and water bodies. Construction 

projects can create the same situation. The District, State established authorities, 


April 26, 2001 4-30 


Federal, State, Municipal governments, and private entities are responsible for their 

operation and maintenance. 

Strategy: Determine ownership and responsibility for flood management systems. 

Actions: 

1. Conduct a study to determine owners of various flood management systems. 

2. Determine who is responsible for the maintenance of the various flood 

management systems. 

3. Develop operation and maintenance plans for the flood management systems 

within the Manatee and Braden River watersheds. This includes developing the 

strategies for maintaining and operating the systems, obtaining easements or 

ingress and egress agreements with property owners, and naming the 

governments or other responsible parties to complete the work. Manatee 

County currently requires private developments to establish responsible 

agencies/associations to manage stormwater systems. 

4. Pursue the Flood Protection Coordination Initiative discussed in the introductory 

paragraphs of this section. 

Issue #6: 

Planning and Implementing Future Flood Management Systems. 

Background: Flood protection should be part of stormwater management planning 

efforts. Some flooding problems in developed areas can be addressed without 

expensive remedies. For example, periodic maintenance keeps existing ditches clean 

and existing detention facilities structurally sound. Acquisitions programs that protect 

floodplains from alteration can also help reduce future flood damage. Stormwater 

management master plans should address existing flooding problems by focusing on 

solutions that minimize environmental impacts and improve water quality and contribute 

to the water supply. This is the comprehensive approach to watershed planning. 

Strategy: Planning for future flood protection efforts through multiple efforts. 

Actions: 

1. Convince municipal and county governments that the entire watershed should 

be examined using a flood prone area analysis. 

2. Encourage municipal and county governments to inventory existing drainage 

systems. 


April 26, 2001 4-31 


3. Encourage county and municipal governments to set goals for flood protection 

based on a appropriate LOS policy. Current state regulations may be 

inadequate for the prevention of flooding conditions. 

4. Incorporate other planning elements in the Stormwater Management Plan 

method, i.e., transportation, major developments with regional significance, 

Greenway/Wildlife corridors, recreation/parks, agricultural development, water 

supply, and environmental management. 

5. The District’s requirements for Stormwater Management Plans should develop a 

consistent framework for management throughout the watershed. A relative 

homogeneous hydrologic regime is exhibited throughout the Manatee River 

Watershed that renders this possible. 

6. Pursue special development codes for building construction in floodplains(i.e., 

No fill for house pads in floodplains. Signage required for depth of flooding etc.) 

This is especially true of low density rural development and agricultural 

operations. 

7. Develop a schedule and funding mechanism for the following projects to reduce 

flood damage: 

a. Bowlees Creek/Oneco Drain Project - involves the enhancement of an 

existing intermediate conveyance system and the construction of 

stormwater management areas to provide flood protection and water quality 

benefits. 


Estimated Cost: $8,100,000 

Time-Frame: Project initiation unknown due to the lack of funding. 

b. Pearce Drain Project - involves the enhancement of an existing 

intermediate conveyance system and the construction of stormwater 

management areas to provide flood protection and water quality benefits. 




c. Gamble Creek - involves the enhancement of an existing intermediate 

conveyance system and the construction of stormwater management areas 

to provide flood protection and water quality benefits. 





April 26, 2001 4-32 


d. Wares Creek Project - entails the enhancement of the conveyance 

capacity of the creek to provide flood protection for the residences in the 

area of the creek. The USACE has developed plans and specifications to 

reshape approximately 15,500 linear feet of the creek. The cost/benefit 

ratio for the project is better than 3:1 

Responsible Parties: The USACE, Manatee County, City of Bradenton, and 

the SWFWMD. 


Time-Frame: Design and permitting is underway. Estimated time to 

complete project is 3-4 years 

Issue #7: 

Funding Sources for Flood Protection Programs. 

Background: Funding mechanisms are available for surface water conveyance 

systems at the federal, state, regional, county and city government levels. Cooperative 

funding programs are available that provide assistance on projects that meet 

predetermined expectations. Flood hazardous mitigation and special projects fall into 

this category. Municipal governments fund stormwater projects through a variety of 

funding mechanisms. The primary mechanism has been through their capital 

improvement program for highway construction or a stormwater utility allocation 

program. However, a source that is typically overlooked in the master planning 

process for a watershed is private entities. Master plans typically address drainage 

system improvements without consideration of participation from the private sector that 

develop and use the system. 

New development or land alteration projects require stormwater conveyance systems. 

These systems are under the jurisdiction of the municipal governments but are not 

necessarily funded, owned, maintained, or operated by the municipality. As a result, 

major conveyance systems and storage areas are constructed by a variety of entities 

with minimal guidance as to their interconnect function with the complete 

infrastructure. Therefore, a well directed master plan and funding program should help 

provide a coordinated stormwater system that meets the expected level of service. 

Versatility will be a key component of this effort. 

Strategy: Develop consistent source(s) of funding for the construction and 

maintenance of flood management systems. 

Actions: 

1. Alternatives to general revenue sources should be considered for funding of 

stormwater projects. 

2. Encourage the establishment of stormwater utility fees from the entities that are 

beneficiaries of the system. 


April 26, 2001 4-33 


3. Encourage the establishment of special assessment districts. 

4. Encourage contributions to regional facilities that are based on a Stormwater 

Management Program. 

5. Develop an educational program to be implemented by the District for county 

and local governments that illustrate the available funding. 

6. Regional stormwater systems should be planned and funded as the upstream 

contributing areas develop or change. 

7. Encourage cooperative projects or piggyback scenarios where many agencies 

contribute to a project developed through a watershed wide study. Credits could 

be provided for developers, roadway improvements (FDOT, Counties, Cities) 

who tie into regional projects that provide efficient stormwater quality and 

quantity storage, wetland mitigation, and protection of the floodplain and its 

function. Provide mechanisms for maintenance and operation funding. 

8. The SWFWMD should participate in the Local Mitigation Strategy to prioritize 

projects and programs that prevent flooding that are funded with disaster 

mitigation funds. 

Issue #8: 

Flood Management Awareness 

Background: Public understanding of flood protection is necessary to build support 

for stormwater management projects or programs to protect the natural floodplain and 

its function. Many of the natural amenities provided in Florida are wetlands, lakes, 

rivers, and estuaries. The public must be made aware of the water level fluctuation of 

these systems along with their biological functions, and why it is important to build the 

necessary infrastructure to protect them. 

Strategy: Develop public education programs that inform the citizens about floodplains 

and their importance in protecting residences from flooding and damage. 

Actions: 

1. Educate public and elected officials that roadways and yards within 

developments are often designed to frequently flood. 

2. Educate the public on the hydrologic cycle and its interaction with the water 

resource and effects on water use. Is flooding part of the water supply solution? 

Flood prone areas are often times part of the water supply system that we 

depend on. 


April 26, 2001 4-34 


3. Educate public and elected officials that restricting development in the floodplain 

will result in significant monetary savings and enhance natural systems in the 

future. 

4. Clarify District flood protection responsibilities. 

5. Clarify the role of FEMA and their responsibilities and contribution to flood 

protection. 

6. Promote cooperation between the responsible jurisdictions on flood protection 

issues. 

7. Provide educational seminars to technical groups. 


April 26, 2001 4-35 


Chapter 5 

5.0 WATER SUPPLY 


The water resources within the Manatee River watershed provide water for agriculture, 

public supply, industry, recreation, and mining. The largest permitted withdrawals in 

the watershed are for agriculture and are pumped almost entirely from ground-water 

sources. Public supply is the second largest permitted use and most of that demand is 

met by surface water withdrawals. Other use-type withdrawals make up only a few 

percent of the demand. 

The Upper Floridan aquifer system (UFAS) is the principal source of ground water. 

Under natural conditions the aquifer is well confined and in poor hydraulic connection 

to the surface water systems. Natural recharge to the UFAS within the Manatee River 

watershed is almost non-existent. The principal recharge area is located in Highlands 

and Polk Counties to the east. A secondary source of water is the intermediate aquifer 

system (IAS). This aquifer is a major source for irrigation water in the watershed, as 

well as functioning as a major confining unit between the UFAS and the near-landsurface 

surficial aquifer system (SAS). For this reason, surface-water and groundwater 

interaction occurs principally between the surface-water bodies (lakes and rivers) 

and the SAS. 

The Manatee River and its tributary, the Braden River, are the principal sources of 

surface water. A dam and reservoir on the Manatee River provide the principal public 

water supply for Manatee County. The Manatee River basin area is 345 square miles 

(Gee and Jenson, 1981), but only 129 square miles (82,240 acres) contribute to the 

county reservoir, Lake Manatee. This reservoir and dam is a man-made, earthen 

impoundment constructed between 1965 and 1967. Lake Manatee is located about 13 

miles east of Bradenton and about 25 miles upstream of Tampa Bay and has a total 

storage capacity of 23,000 acre-feet (7.5 billion gallons) when full. At maximum stage, 

the reservoir covers about 1,800 acres and extends some six miles upstream. The 

estimated mean depth is 12.8 feet. The earthen dam is approximately 5,000 feet long 

with a minimum height of 44 feet. Water depths near the dam vary from 38 to 40 feet. 

Seepage through the dam is collected into a drain and the water level in the reservoir is 

controlled by Tainter gates within the concrete spillway. The preferred maximum stage 

is 40 feet NGVD and the minimum is 21 feet, NGVD. Usable storage volume between 

maximum and minimum stage is 20,300 acre feet (6.61 billion gallons) (SOURCE: CDM 

1984a, 1990). 

Similarly, a dam and reservoir on the Braden River, the largest tributary to the Manatee 

River, provide the principal public water supply for the City of Bradenton. The Braden 

River enters the Manatee River downstream of Manatee County’s dam. The Braden 


April 26, 2001 5-1 

Chapter 5 - Water Supply

River basin area is 80 square miles but only about 59.5 square miles contribute to the 

city’s reservoir, known as the Evers Reservoir. 

The original dam that created the present day Evers Reservoir was an earthen dam 

(Ward Dam) constructed in 1939. The reservoir and dam were renovated in 1985. The 

area of the reservoir is about 376 acres when water levels are at the level of the weir. 

The dam is over 1,300 feet across and includes a broad-crested weir, reported to have 

been established in 1962. The elevation of the weir is reported as 3.85 feet NGVD, 

however variations in the elevation may be as much as a foot. An impermeable 

membrane was placed over the dam faces during the 1985 renovation and appears to 

have significantly affected flows over the dam. 

5.2 Permitted Water Use 

Permitted water use for the watershed is 150 MGD for ground water and 42 MGD for 

surface water. The largest permitted quantity by use type is 123 MGD for agriculture. 

Public supply is permitted for 54.6 MGD but withdrew the largest quantity in 1996. All 

other uses combined are permitted for only 14.53 MGD. Permitted water quantities by 

use type are shown in Table 5-1. Water use as estimated by the SWFWMD is 

generally much less than permitted quantities. This is particularly true for agriculture 

users, whose permitted quantities are based on a two-in-ten drought year and 

maximum acreage that might be planted during the life of the permit. In 1996, it was 

estimated that only 30 per cent of permitted quantities were withdrawn for agriculture. 

Table 5-1: 1996 Permitted quantities by use type for the Manatee River watershed 

in million gallons per day. 

GROUND-WATER 

USE TYPE METERED n UNMETERED n TOTAL 

Agriculture 113.772 89 9.002 102 122.774 

Industrial-Commercial 0.589 2 0.029 2 0.618 

Mining-Dewatering 8.995 3 0.000 0 8.995 

Public Supply 13.985 7 0.010 3 13.995 

Recreation 2.392 11 1.335 24 3.727 

TOTALS 139.733 112 10.376 131 150.109 

SURFACE-WATER 

USE TYPE METERED n UNMETERED n TOTAL 

Agriculture 0.000 7 0.000 2 0 

Industrial-Commercial 0.000 1 0.000 0 0 

Mining-Dewatering 0.000 2 0.000 0 0 

Public Supply 40.600 3 0.000 0 40.6 

Recreation 1.187 7 0.007 4 1.194 

TOTALS 41.787 20 0.007 6 41.794 

Note: n - the number of permits in category. 

Metered refers to permits required to meter withdrawals. 


April 26, 2001 5-2 


Agriculture withdrawals are entirely from gound water and occur on a highly seasonal 

basis. The appearance of zero surface water being permitted for agriculture is 

misleading when 0.705 MGD of surface water withdrawals were reported. Agriculture is 

sometimes permitted for surface water withdrawals from ponds that are supplied by 

ground water. In order to keep the total quantities of permitted water consistent, these 

quantities are not included in the permitted totals. 

Typically, the largest agricultural irrigation withdrawals are for vegetables, tomatoes, 

and citrus, in that order. In 1996, 35.5 MGD were withdrawn for agriculture (Table 5-2). 

Vegetables, tomatoes and citrus use accounted for 43.4 percent, 26.8 percent and 13.5 

percent, respectively. These concentrated seasonal withdrawals produce a significant 

decline in the potentiometric surface of the UFAS, especially during the Spring dry 

season. In 1989, most of the UFAS potentiometric surface within the watershed was 

below sea level. 

Manatee County Public Utilities Department is the largest public supplier in the 

watershed. They are permitted an annual-average withdrawal of 48.86 MGD. Most of 

this quantity is permitted from the Lake Manatee reservoir but some 28.5 percent is 

permitted from ground-water sources. Table 5-3 shows the various components of this 

total. The City of Bradenton is the only other public supplier in the watershed. They 

are permitted an annual-average withdrawal of 6.95 MGD from the Evers Reservoir. 

In 1996, public supply withdrew 43.7 MGD. This was the largest withdrawal for any use 

type (Table 5-2). MCPUD withdrew 36.341 MGD of which 24.306 MGD was from the 

Lake Manatee reservoir. An additional 12.035 MGD was pumped from the East County 

Well Field. The City of Bradenton withdrew 5.543 MGD from the Evers Reservoir. 

Manatee County wholesales water to various other utilities in and out of the county. 

The largest quantity is provided to Sarasota County Utilities District-1, which has a 

contract for an annual average of 12 MGD up to the year 2013. In 1996, MCPUD 

provided Sarasota County with 9.35 MGD. 

After agriculture and public supply, all other withdrawals totaled only 3.949 MGD. 

Mining and dewatering are permitted for 8.995 MGD, but withdrew only 1.34 MGD in 

1996. Most of that withdrawal was for sand mining, a process which generally 

recirculates surface water and has little consumptive use. Commercial and industrial 

uses are permitted for 0.62 MGD and withdrew 0.35 MGD in 1996. The principal 

commercial and industrial uses are for food processing and packing. Recreation is 

permitted for 4.92 MGD and withdrew 2.26 MGD from a combination of surface water 

and ground water sources in 1996. The principal categories within recreation are 

cemeteries, parks and golf courses. 

5.3 New Water Sources Initiative (NWSI) 

The NWSI provides a unique funding source for the development of alternative water 

supply projects in the District. Alternative sources of supply are needed to reduce 


April 26, 2001 5-3 


dependence on groundwater and to meet the demands of the growing population. 

Examples of alternative sources of supply include reclaimed water, stormwater, surface 

water, seawater desalination and conservation. 

Beginning in FY 1994, the District Governing Board allocated $10 million per year for 

eligible NWSI projects. The Basin boards have also contributed a combined total of 

approximately $10 million per year beginning in FY 1995. Local governments and 

other cooperators are required to match the District and Basin Board funds. NWSI 

projects are eligible for 25 percent matching fund from the Governing Board, 25 percent 

matching fund from the appropriate Basin Board(s), and the remaining 50 percent from 

the local cooperators. The Basin Board contribution may be split among one or more 

basins, depending on the geographical area and population that benefits from the 

project. This is especially true in Hillsborough County, which has three Basin Boards 

(Hillsborough, Northwest Hillsborough and Alafia). Individual Basin Board contributions 

vary, but are generally proportional to the share of benefits received in the basin. 

Each year local cooperators submit potential projects to the District through the Basin 

Cooperative Funding program for NSWI funding. The projects are reviewed and 

ranked by staff. The review includes input from the statutorily required Alternative 

Water Supplies Grants Advisory Committee established by the District in 1995. 

Projects are evaluated and compared using a set of criteria that reflect District priorities 

for NWSI projects. The NWSI criteria are grouped into qualification criteria and 

prioritization criteria. Projects are assigned scores for each of the criteria and ranked 

based on their comparative scores. All projects must meet the qualification criteria to 

be eligible for NWSI funding. The qualification criteria are as follows: (1) positive 

environmental impacts, (2) cooperator history, (3) consistency with the DWMP and 

local comprehensive plans, (4) project permittability, and (5) schedule. Prioritization 

criteria are as follows: (1) degree to which stress on the water resource will be relieved 

or avoided by the project, (2) location of the project relative to designated Water Use 

Caution Areas, (3) cost-effectiveness, (4) degree to which the project addresses District 

initiatives other than water supply (i.e. flood control, water quality, and natural 

systems), (5) degree of local/regional support and participation, and (6) additional 

efforts by the cooperator which would enhance the long-term impact of the project. 

Forty-six projects with estimated costs totaling $250 million were submitted to the 

District in 1994 for NWSI funding. Twelve “cornerstone” projects were selected the first 

year based on recommendations by District staff, Advisory Committees, (Public Supply, 

Industrial, Agricultural, and Green Industry) and action groups made up of members 

from all water use sectors. Four additional projects were approved for FY1996. The 

sixteen approved NWSI projects will provide up to 150 million gallons per day of water 

to meet current and future water needs. The projects will also provide environmental 

benefits including rehydration of stressed lakes and wetlands, reduction of groundwater 

withdrawals in stressed areas, improved surface water quality, groundwater recharge, 

enhancement of wildlife habitat and flood control improvements. Eight of the sixteen 

projects are located in the SWUCA, and will provide positive environmental benefits to 

the water resource in the area. These projects include the Peace River Option, the 


April 26, 2001 5-4 


Manatee County Agricultural Reuse Supply and the Punta Gorda Aquifer Storage and 

Recovery (ASR). 

5.3.1 Reclaimed Water Use 

Another source of water used to offset potable water withdrawals is the use of 

reclaimed water for non-potable demand such as industrial use, power plant cooling, 

agricultural irrigation and landscape irrigation. Reclaimed water is water that has 

received at least secondary treatment and is reused after flowing out of a domestic 

waste-water treatment plants (WWTP). 

In 1997, Manatee County waste-water treatment plants (WWTP) had a capacity of 

37.20 MGD and handled flows of 24.46 MGD. The County’s reuse system capacity 

was 28.8 MGD and in 1997 handled an average flow of 10.46 MGD (see Table 5-4). 

Table 5-2: 1996 Estimated water use (SWFWMD, 1997). 

USE TYPE SW GW TOTAL 

Agriculture 

Citrus 0.023 4.762 

Field Crop 0.613 1.474 

Melons 0 0.189 

Ornamental 0.04 0.287 

Pasture 0.001 0.888 

Sod 0 0.134 

Strawberry 0 0.164 

Tomatoes 0 9.466 

Vegetables 0.028 15.447 

Other 0 2.657 

Subtotal 0.705 35.468 36.173 

Industrial/Commercial 

Food Packing 0 0.015 

Food Process 0 0.003 

Other 0.186 0.146 

Subtotal 0.186 0.164 0.35 

Mining/Dewatering 

Phosphate 0 0.146 

Sand 1.195 0 

Subtotal 1.195 0.146 1.341 

Public Supply 

Subtotal 29.848 13.814 43.662 

Recreation/Aesthetics 

Cemetery/Parks 0.039 0.361 

Golf Courses 0.962 0.893 

Other 0 0.003 

Subtotal 1.001 1.257 2.258 

TOTALS 32.935 50.849 83.784 


April 26, 2001 5-5 


Table 5-3: Principal public supply utility use and permitted quantities, SWFWMD 

(RDB). 

Permit 

Number 

Permittee Name 

GW 

or 

SW 

Permitted 

Annual Avg 

(MGD) 

Permitted 

Peak Month 

(MGD) 

1996 Use 

(MGD) 

006392 Bradenton, City of SW 6.950 8.130 5.906 

007345 IMC Fertilizer & Manatee County GW 1.960 1.960 1.663 

005387 Manatee County, Public Works SW 34.900 46.700 25.577 

007470 Manatee County, Public Works GW 12.000 13.500 11.05 

Note: 1 -Includes 0.004 Mgd from ground water. GW/SW are ground water and surface water, respectively. 

Table 5-4: Manatee River CWM Reuse Summary. 

1997 2010 2020 

Capacity Flow Reuse Capacity Flow Reuse Capacity Flow Reuse 

City of Bradenton 6 5.2 0.24 9 7.14 7.14 9 7.5 7.5 

City of Palmetto 2.4 1.18 0.25 2.4 1.62 1.62 2.4 1.85 1.85 

Manatee County SW 18 13.11 5 18 15.56 15.56 22 16.45 16.45 

Manatee County SE 5.4 2.53 2.53 11 5.64 5.64 11 7.43 7.43 

Manatee County N 5.4 2.44 2.44 11 4.72 4.72 11 5.98 5.98 

TOTALS 37.2 24.46 10.46 51.4 34.68 34.68 55.4 39.21 39.21 

- 1997 Information from 1997 Reuse Report 

- 2010 & 2020 Capacity, Flow and Reuse information from projects and utilities reuse plans 

5.4 The Southern Water Use Caution Area 

The purpose of the District’s Southern Water Use Caution Area (SWUCA) management 

process is to meet the water supply needs of the region while protecting the water 

resource and related natural systems. 

Addressing the water resource issues of the Southern Water Use Caution Area has 

involved a lengthy process: 

• The District’s Governing Board declared the Southern Water Use Caution 

Area (SWUCA) in 1992. A "water use caution area" is designated where 

water resources are or will become critical in the next 20 years. 

Encompassing approximately 5,100 square miles, SWUCA includes all of 

Manatee, Sarasota, Hardee and DeSoto counties and portions of 

Hillsborough, Charlotte, Polk and Highlands counties. SWUCA water 

resource concerns include the decline of lake levels along the Highlands 


April 26, 2001 5-6 


Ridge, where most Floridan Aquifer recharge occurs, and advancing 

coastal saltwater intrusion in the Floridan aquifer. 

• The District’s Governing Board approved a SWUCA rule in 1994 following 

a significant public input process. The objectives of the rule were to 

significantly halt saltwater intrusion into the Floridan aquifer along the 

coast, stabilize lake levels in Polk and Highlands counties, and limit 

regulatory impacts on the region’s economy and existing legal users. The 

rule was intended to gradually reduce existing permitted quantities 

because the existing aquifer level was already below the proposed 

minimum level (the limit at which further withdrawals would cause 

significant harm to the water resources). The rule also included a 

mechanism called reallocation which would have allowed the voluntary 

redistribution of existing permitted quantities to new uses and locations 

within SWUCA. 

• Several parties filed objections to parts of the rule, leading to an 

administrative hearing. The administrative law judge’s Final Order was 

issued in March 1997. The Final Order upheld the District’s minimum 

Floridan aquifer levels and the science used to establish them, along with 

the phasing in of conservation measures. However, the ruling also found 

certain provisions invalid, including reallocation and preferential treatment 

of existing users. The District also withdrew key provisions of the rule, 

including the minimum level, based upon a settlement agreement which 

had been reached with agriculture parties. A number of parties appealed 

the ruling to the Second District Court of Appeals. 

• In September 2000, the Second District Court of Appeals ruled on the 

challenges presented to the original SWUCA rules. The Court found in 

favor of the District on all 13 points on appeal. The issues on appeal and 

the Court’s findings are described below. These findings support the 

District’s strategy for management of the water resources in the SWUCA 

and District wide. 

• The District argued that several of the issues appealed by others should 

not be reviewed since the rules had been withdrawn. The Court agreed. 

Those issues were: 1) whether socio-economic factors in addition to 

science may be taken into account in setting a minimum level or flow, 2) 

whether existing users can be preferred over new users; and 3) whether 

Hardee and DeSoto counties had a right to additional hearings before the 

Governing Board. The Appeals Court sided with the District on such 

issues as: 

1) That all applicants must meet the "three prong test" where they must show that; 

the proposed use of water must be reasonable-beneficial, does not interfere with 

an existing legal use of water, and is consistent with the public interest. 


April 26, 2001 5-7 


2) Verified the District’s criteria for issuance of a permit. 

3) Confirmed the District’s Basis of Review for permit issuance. 

4) Confirmed District’s authority to require an investigation into the availability and 

use of reclaimed water for certain applicants for new quantities of ground water. 

5) Confirmed District’s authority to require an investigation into the availability and 

use of desalinated water. 

All provisions of the previously proposed SWUCA rule have been stayed until the 

appeals process is concluded. The District must now evaluate this rule, originally 

proposed eight years ago, to determine what portions should be allowed to go into 

effect, what portions need to be amended, and which portions should be withdrawn. 

During this lengthy appeals process, the District began a reassessment of the SWUCA 

resource concerns and management strategies. Major factors to be considered in this 

reevaluation included: 

• Groundwater permitted quantities and use in the SWUCA had not grown 

as had been previously anticipated; 

• Groundwater levels had not progressively deteriorated but rather were 

approximate to the previously proposed minimum level; 

• New legislative provisions were adopted in 1997 giving the District new 

water supply policy directives, water resource and supply planning and 

development responsibilities, and guidance for "recovery and prevention 

strategies" associated with minimum flows and levels. 

In April 1998 the District published the "SWUCA Information Report" in an effort to 

summarize these recent trends and events. In addition, a "Conceptual Management 

Strategy" was approved by the District’s Governing Board in September 1998 for 

purposes of gaining public input on a revised management approach. Specific resource 

management goals for the SWUCA, as expressed in the Conceptual Management 

Strategy, remain largely unchanged: 1) to minimize salt water intrusion in order to 

protect the ground water system as a water supply source, and 2) to minimize the 

influence of ground water and surface water withdrawals on lake levels to protect lake 

functions. Realization of these goals will require a coordinated, regional effort that 

includes incentives and projects that investigate, correct and prevent harm to the water 

resource; regulatory initiatives; development of alternative sources; and widespread 

education efforts. 

As part of developing an updated strategy, a SWUCA Work Group was formed to 

review management approaches outlined in the Conceptual Management Strategy, as 

well as any alternative approaches which might warrant consideration. Work Group 

deliberations and public meetings started in October 1998 and continue today. The 

Work Group has helped to develop and review other recommendations that include: 


April 26, 2001 5-8 


• Enhancement of monitoring networks which measure ground water levels, 

rainfall, lake levels, stream discharges, ground water quality, water use, 

well construction information, and hydrogeological characteristics; 

• Completion of the ongoing Water Resource Assessment Projects 

(WRAPs) to improve our knowledge of the hydrogeologic system; 

• Completing evaluations of the intermediate aquifer to establish and 

expand understanding of the characteristics of that aquifer; 

• Determination of minimum flows and levels (MFLs). MFLs are scheduled 

to be established in 2001 for a number of lakes along the Highlands 

Ridge, and the Floridan Aquifer; 

• Continuation and expansion of agricultural irrigation research, as well as 

enhanced water conservation by all use sectors. 

As previously mentioned, during its 1997 session, the Florida Legislature amended the 

Water Resources Act (Sections 373.036, F.S.) to clarify the water management 

districts’ responsibilities relating to water supply planning and water resource 

development. The legislation required the District to prepare a District wide Water 

Supply Assessment. This Assessment functions similarly to the previous Needs and 

Sources Report (1992), in that it evaluates water demand projections to the year 2020 

and compares these demands to the availability of known water sources. In those areas 

where existing or reasonably anticipated sources of water and conservation efforts will 

not be adequate to meet current or future water supply needs, a Regional Water 

Supply Plan (RWSP) must be prepared which further investigates water resource and 

supply development opportunities. The District wide Assessment was completed in 

1998 and concluded that a RWSP had to be prepared for a ten county region of the 

central and southern portions of the District, including all of the SWUCA. The RWSP 

has become the vehicle by which water resource and supply development opportunities 

which can contribute to resolving the SWUCA resource management problems are 

being identified. 

The District is currently in the process of preparing this RWSP, and has turned to the 

SWUCA Work Group and a similar group representing the Northern Tampa Bay area, 

as a means of obtaining input. The RWSP is being developed in an open public 

process, in coordination and cooperation with local governments and utilities, regional 

water supply agencies, the agricultural community, business and industry 

representatives, environmental organizations and other affected and interested parties. 

This has proven quite useful in identifying data gaps or other ways to improve the 

RWSP process and results. For example, how the District calculates water use in areas 

like Sarasota County where many publically supplied users also have separate 

irrigation wells is being reexamined in the development of the RWSP. This will allow 

the District to avoid underestimating actual demands while clearly delineating whether 

this is a localized or regional situation. Estimation of future agricultural water needs has 


April 26, 2001 5-9 


similarly benefitted from the involvement of the District’s Agricultural Advisory 

Committee and specific trade organizations. Once completed, the RWSP will also 

contain a five-year work program for the implementation of water resource development 

projects. 

The RWSP will continue in draft form for public input until December 2000, and be 

considered for approval by the District’s Governing Board by March 2001. 

The SWUCA management approach includes not only completion and implementation 

of the RWSP, but the establishment of minimum flows and levels and any 

accompanying recovery and prevention strategy. Key SWUCA MFLs are scheduled for 

adoption no later than December 2001. 

5.5 Literature Reviewed 

A number of planning documents and technical reports address water supply issues in 

the Manatee River Watershed. A complete listing of these documents appears in the 

annotated bibliography for the Manasota CWM. The most significant documents are 

summarized below. 

5.5.1 Water Supply Planning Studies 

The District Water Management Plan (DWMP) is a broad-based planning document 

that addresses activities related to water supply, flood protection, water quality, and 

natural systems (SWFWMD, 1995). The plan identifies current programs, issues, and 

strategies for regional water management. The water supply element of the DWMP is 

comprised of two sub-elements: (1) needs and sources and (2) source protection. 

CDM (1990) developed a needs assessment for Manatee County Public Utilities 

Department. The conclusion of the report was that Manatee County would be unable to 

meet their peak month and peak day obligations in 1991. To meet these requirements 

Manatee County obtained two additional groundwater withdrawal permits totaling 15.46 

MGD. Today Manatee Counties permitted surface water (permit number 005387) and 

ground-water (permit number 07345, and 07470) withdrawals to total 48.8 MGD, and 

their use in 1997 totaled 38.29 MG (SWFWMD 1999). 

The District developed a Needs and Sources Plan that was adopted in 1992 and 

incorporated in the DWMP. The objective of the plan was to examine water needs 

(demands) and probable sources for the period 1990 through 2020 to provide a 

framework for water supply management (SWFWMD, 1992). The 1992 Needs and 

Sources Plan recognized that ground-water resources are stressed in the Southern 

Water Demand Planning Area that includes the Manatee River Watershed. 

Conservation, reuse, surface water and limited ground-water development were 

identified as potential sources to meet future needs in this area. 

The DWMP addresses source protection primarily through Water Resource 

Assessment Projects (WRAP) and the declaration of Water Use Caution Areas 

(WUCA). The Manatee River Watershed lies within the Eastern Tampa Bay WRAP 


April 26, 2001 5-10 


area and the Eastern Tampa Bay WUCA. The Eastern Tampa Bay WRAP report 

(SWFWMD, 1993) contains the hydrologic analyses and provides the technical basis 

for ground-water resource development in the area as well as the entire Southern 

Water Demand Planning area. The Eastern Tampa Bay WUCA was declared to 

address the salt-water intrusion problem in the SWFWMD’s southern coastal area. 

Other programs involving source protection, which are discussed in the DWMP, include 

water use permitting, water shortage management and land acquisition. 

Water supply issues identified in the DWMP include: (1) water allocation strategies, (2) 

linkage of water use planning to local government comprehensive planning, (3) 

compliance and enforcement, (4) alternative supplies, (5) additional data collection, (6) 

watershed water budget approach to water management, and (7) water use fees. 

Options to address each issue have been evaluated and are outlined in the DWMP. 

To aid the local governments in their comprehensive planning efforts the SWFWMD 

produced the Ground-water Basin Resource Availability Inventory (GWBRAI) report 

series by county. The GWBRAI: Manatee County was published in 1988. These 

reports provided water resource information and reviewed overall water supply sources 

and conditions. Sources included water reuse, desalination and conservation. 

The SWUCA Management Plan (1992, DRAFT) outlined specific steps to manage the 

area ground-water supplies, including the Manatee River water shed area. 

In 1997 the Florida Legislature amended Chapter 373, Florida Statutes (F.S.) Requiring 

new regional water supply planning. These new regional water supply planning 

requirements were codified in s.373.0361, F.S., which required the District to publish a 

Regional Water Supply Plan (RWSP). 

This Draft Regional Water Supply Plan, published in July of 2000, is an assessment of 

projected water demands and potential sources of water to meet these demands for the 

period from 1995 to 2020. The RWSP is developed for a ten-county area that extends 

from Pasco County in the north to Charlotte County in the south. The purpose for 

preparing the RWSP is to provide the framework for future water management 

decisions in areas of the Southwest Florida Water Management District (District) where 

the hydrologic system is stressed due to ground-water withdrawals. The RWSP 

shouws that sufficient water sources exist in the planning region to meet future 

demands with some replacement of the current withdrawals causing hydrologic stress. 

In addition, it identifies potential options and associated costs for developing these 

sources. Options identified in this report are not intended to represent the District’s 

most “preferable” options for water supply development. They are, however, provided 

as reasonable concepts that water users in the region can pursue in their water supply 

planning. Water users can select a water supply option as presented in the plan or 

combine elements of different options that better suit their water supply needs. The 

plan provides information to assist water users in developing funding strategies to 

construct water supply development projects. 


April 26, 2001 5-11 


5.5.2 Surface Water Studies Related to Water Supply 

Many of the surface water studies related to water supply have dealt with the 

dependable yield of the reservoir. Camp, Dresser and McKee (CDM, 1984a) reported 

sixteen different previous estimates of “safe yield” from the Lake Manatee Reservoir 

and in 1992 CDM performed another evaluation. The maximum estimate was 50.5 

MGD made by Bromwell Engineering (1980) and the minimum was 28 MGD estimated 

separately by the SWFWMD (1981) and CH2MHill, Inc. (1981). The County reported 

that dependable yield was less than reported in many of the reports based on 

experience during the 1985 and 1989 droughts (Manatee County PWD, 1990). In 

1984, CDM re-evaluated the 95 percent dependable yield of the reservoir and 

determined it to be 33.2 MGD. The analyses did not include the likely 2 to 3 MGD 

contributions from agricultural irrigation runoff. 

D.P. Brown (1983) identified three areas within the water shed in which additional 

surface water impoundments might be developed: the North Fork, the East Fork and 

near Myakka Head. The County has also identified Gillie Creek for the possible 

development of an additional surface water impoundment. 

5.5.3 Ground Water Studies Related to Water Supply 

The major thrust of most ground-water studies has been an investigation of the aquifers 

and their properties, especially the UFAS. One of the earliest studies, carried out by 

H.M. Peek (1958) for the U. S. Geological Survey, documented the general condition of 

the ground-water resources within the county. D.P. Brown (1983) surveyed and 

reviewed ground-water conditions of the county. Between 1979 and 1985, CH2M Hill, 

Inc made numerous investigations into the feasibility of aquifer storage and recovery 

(ASR) in the Manatee River watershed. The intermediate aquifer system is a 

significant aquifer for small users and domestic self-supply (Duerr, et al, 1988). 

In 1990, Upper Floridan aquifer ground-water levels had been in continual decline 

since the early 1930s (SWFWMD, 1993). By the late 1980s, during the Spring of each 

year, ground-water levels would be tens of feet below sealevel over several hundred 

square miles. Because of the serious potential for salt-water intrusion the SWFWMD 

declared southern Hillsborough County, most of Manatee County and a small part of 

Sarasota County a Water Use Caution Area (SWFWMD, 1993). This Water Use 

Caution Area, or WUCA, was called the Eastern Tampa Bay WUCA. To address the 

problem the SWFWMD adopted specific rules in November 1990 governing the 

withdrawal of ground-water from the area (Chapter 40D-2 FAC, Water Use Permitting 

Rules Section 7.2). 

5.6 Available Data 

The SWFWMD maintains two pertinent data bases with data on water supply: the 

Water Management Data Base (WMDB) and the Regulatory Data Base (RDB). The 

WMDB contains data pertaining to the condition of the water resources in general (i.e. 

flows, levels, and water quality) while the RDB contains data related to water use 


April 26, 2001 5-12 


permits (i.e. permittee data, withdrawal quantities, water quality, et cetera). Other 

agencies or organizations maintaining data bases with related data are the U. S. 

Geological Survey, Florida Department of Environmental Protection and the 

SWFWMD’s Ambient Ground-water Quality Monitoring Program department. 

5.7 Outstanding Permitting Issues 

None. 

5.8 Governmental Activities and Other Watershed Initiatives 

The SWFWMD has two programs to assist water resource development within the 

District. First, through the Cooperative Funding program, the SWFWMD jointly funds 

with the counties and municipalities water resource projects from the four areas of 

responsibility. Cooperative Funding projects are approved by the Basin Boards to fund 

up to one-half of a projects cost. The Manatee River Water Shed is located within the 

jurisdiction of the Manasota Basin Board. The SWFWMD has jointly funded five 

Cooperative Funding projects to enhance water supply in the Manatee River 

Watershed. Typical projects in the water shed have been for the construction of 

storage tanks and transmission lines for the implementation of reuse of reclaimed 

water. Total funds expended to date by the SWFWMD have been $1,748,000. 

Another major funding effort subsidized by the SWFWMD has been the New Water 

Sources Initiative (NWSI) program. The NWSI program, with approval from the 

Governing Board, will fund up to 50 percent of the cost of alternative water sources 

which have regional water source benefits. Three separate projects related to an 

ambitious expansion of regional reuse have been funded under this program with 

$17,497,000 of SWFWMD funds. Manatee County is the principal recipient of these 

funds but the Cities of Bradenton and Sarasota and Sarasota County are joint 

participants in one of the projects. 

5.9 Water Supply Issues 

ISSUE #1: Water use and land use planning must be coordinated for both to be 

effective. 

Background: There is no clear linkage between the planning and implementation 

programs of the District and the land use planning decisions of local governments 

(SWFWMD, 1995). The District is the agency charged with primary responsibility of 

water management decisions within its region and is a central source for water related 

research and information. Local governments exercise primary authority over land use 

through long-range (20 year) Local Government Comprehensive Plans. Existing 

statutes relating to land and water planning and management create two separate 

tracks with minimal connection and no requirements for consistency between them. 

Integration between land and water use planning and management processes is 

essential to either being effective in accomplishing its objectives. This issue was the 

subject of the Governor’s Task Force on Land and Water Planning. 


April 26, 2001 5-13 


Strategy: Work to have water supply as a consistency requirement for Local 

Government Comprehensive Plans. 

Actions: 

1. Use the District’s Needs and Sources report as the source document for water 

supply availability. 

2. Ensure District lobbyists make consistency a part of the legislative agenda. 

3. Develop a linkage mechanism between local governments. 

Strategy: Improve coordination between land and water planners. 

Actions: 

1. Increase District involvement with the Regional Planning Councils and local 

government planning departments. 

2. Develop an annual report summarizing the status of water supply, water 

resources, and new regulations for distribution to local land use planners and 

others. 

3. Develop Memorandum of Understanding between the District and local 

governments which provides that local governments will give advance notice to 

the District when DRIs and large Comprehensive Plan amendments are 

proposed. 

4. Coordinate five-year planning documents, such as Comprehensive Plan Updates 

and Basin Plans, on the same time frame. 

ISSUE #2: Current demands for water supply are at or near the limits of 

traditional water resources of the area. 

Background: The Southwest Florida Water Management District (District) is one of 

five districts charged with protecting and managing the State of Florida’s water 

resources. During the 1997 legislative session, the Florida Legislature amended the 

Water Resources Act (Sections 373.036 and 373.0361, Florida Statutes) to clarify 

agency responsibilities relating to water supply planning and water resource 

development. A district-wide Water Supply Assessment was required of each water 

management district by July 1, 1998 (House Bill 715). In addition, the districts are 

required to develop Regional Water Supply Plans in regions where demands are 

expected to exceed available water supplies by the year 2020. 

Water supply withdrawals from ground-water and surface-water sources are very near 

their limit capacities. Salt-water intrusion is deemed to be a threat to ground-water 

resources at withdrawal rates higher than the 1991 through 1996 average withdrawals. 


April 26, 2001 5-14 


There is little excess flow available from Manatee and Braden Rivers. But needs and 

sources investigations (SWFWMD, 1992 and 1997) show continued demand growth by 

the major users of public supply and agriculture. 

Strategy: Establish minimum flows and levels to protect water supplies and related 

resources and reverse unacceptable effects where they have occurred. 

Actions: 

1. Set minimum stream flow requirements in the Manatee River watershed. 

2. Set minimum aquifer levels in the UFAS and the intermediate aquifer system 

within the watershed. Aquifer levels must be established in coordination with the 

remainder of the SWUCA. 

3. Develop a recovery plan for areas that are below minimum flows and levels at the 

time of implementation. 

4. Establish acceptable criteria in coordination with SWUCA II management plan. 

Strategy: The District’s Water Supply Assessment was completed in June 1998. 

Based on the findings of this work, Regional Water Supply Plans are needed for the 

West-Central, East-Central, and Southern Planning Regions. The Water Supply Plans 

must be completed by March 31, 2000. The plans are a first step in the District’s 

ongoing efforts related to water resource and water supply development. In addition to 

this short-term effort, the District will continue to identify and plan for water resource 

and water supply development throughout its 16-county area. 

Actions: 

Based on the findings of the Assessment, Regional Water Supply Plans are needed for 

the West-Central, East-Central, and Southern Planning Regions. In these three 

regions, existing supplies are insufficient to meet future reasonable and beneficial 

needs through 2020. The Water Supply Plans must be completed by March 31, 2000. 

The plans are a first step in the District’s ongoing efforts related to water resource and 

water supply development and will contain the following elements: 

• Projected water demands for all use sectors through 2020 

• Available existing sources 

• Deficit in available supplies 

• Minimum flows and levels 

• Recovery and prevention strategies 

• Water supply development options 

• Water resource development options 

• Five-Year Work Plan for water resource development projects 

• Funding mechanisms and project schedules for selected projects 


April 26, 2001 5-15 


The District initiated the development of Regional Water Supply Plans in Fall 1998. 

Staff have developed a work plan and schedule and are currently contracting with five 

(5) consultants to assist in this effort. The consultants will help identify and evaluate 

potential water supply and water resource development projects including: (1) surface 

water/storm water, (2) reclaimed water, (3) seawater desalination, (4) agricultural 

conservation, (5) non-agricultural conservation. Brackish-water sources will also be 

evaluated by District staff. The District is coordinating closely with the state’s other four 

water management districts regarding the development of Regional Water Supply 

Plans. 

Strategy: Promote conservation and responsible use of water resources. 

Actions: 

1. Increase efficiencies for public supply 

2. Work within the framework of the SWUCA II management plan. 

Strategy: Protect water quality of supply 

Actions: 

1. Address the reclaimed water in the watershed issue. 

2. Address the agricultural runoff issue (see Water quality or Natural system AOR) 


Ardaman and Associates, September 1978, Addendum to Development of Regional 

Impact, Duette Mine, Swift Agricultural Chemicals Corp, prepared for Tampa Bay 

Regional Planning Council, pp 32-35. 

Ardaman and Associates, October 1979, Surface water quality resource document, 

Draft environmental impact statement, for Estech General Chemicals Corp., 

Duette Mine, Manatee County, Florida, pp 105-109. 

Aucott, W.R., 1988, Areal variation in recharge to and discharge from the Floridan 

aquifer system in Florida, U.S. Geological Survey, Water-Resources 

Investigations Report 88-4057, 1 p. (Map). 

Bromwell Engineering, 1980, Safe yield analysis of the Lake Manatee reservoir by 

queuing theory; Bromwell Engineering, Inc. Lakeland, Florida, pp. 36. 

Brown, D. P., 1983, Water Resources of Manatee County, Florida: U.S. Geological 

Survey WRI 81-74; pp. 


April 26, 2001 5-16 


Camp, Dresser, McKee, Inc., 1981(?), Engineering study of water supply system 

(Phase I): Manatee County Utilities Department, pp. ?? 

Camp, Dresser, McKee, Inc., 1981a, Consumptive Use Permit: Manatee County Public 

Utilities Department, pp. ?? 

Camp, Dresser, McKee, Inc., 1981b, SWFWMD Consumptive Use Permit Release 

Schedule program: Manatee County Public Utilities Department, pp. ?? 

Camp, Dresser, McKee, Inc., 1983, Engineering study of water supply system (Phase 

II): Manatee County Public Utilities Department, pp. ?? 

Camp, Dresser, McKee, Inc., 1984a, Manatee County Public Utilities Department Water 

Supply Master Plan (1983-2013): Manatee County Utilities Department, pp. ?? 

Camp, Dresser, McKee, Inc., 1984b, Downstream effects of permitted and proposed 

withdrawals from the Lake Manatee reservoir: Manatee County, pp. ?? 

Camp, Dresser, McKee, Inc., 1985, Southeast area stormwater management study: 

Final Report: Prepared for Manatee County Planning and Development 

Department, pp. ?? 

Camp, Dresser, McKee, Inc., 1988, Briefing Document for Effluent Reuse Feasibility 

Study and Master Plan for Urban Reuse to Manatee County Public Works 

Department: Manatee County, pp. ?? 

Camp, Dresser, McKee, Inc., 1990a, Individual water use permit application and 

supplemental form: permit renewal and modification: Manatee County, pp. ?? 

Camp, Dresser, McKee, Inc., 1990b, Effluent reuse feasibility study and master plan for 

urban reuse: Southwest Florida Water Management District and Manatee 

County, pp. ?? 

Camp, Dresser, McKee, Inc., 1990c, Manatee County Water Supply Needs Document; 

prepared for Manatee County Public Works Department. 

Camp, Dresser, McKee, Inc., 1992, Lake Manatee Water Resources Development 

Report: prepared for , pp. ?? (as cited in N&S REVIEW) 

Camp, Dresser, McKee, Inc., 1996, Manasota Basin water reuse system inventory: 

Southwest Florida Water Management District, pp. ?? 

CH2M Hill, Inc., 1978, Preliminary feasibility report: Augmentation of Lake Manatee 

reservoir from the Little Manatee River: Southwest Florida Water Management 

District, pp. 35. 

CH2M Hill, Inc., 1979, Preliminary feasibility of recharge-recovery wells in the Lake 

Manatee area, Southwest Florida Water Management District, pp. 28. 


April 26, 2001 5-17 


CH2M Hill, Inc., 1981, Recharge-recovery at Lake Manatee, Phase One, Task One; 

Water supply alternatives analysis: Southwest Florida Water Management 

District, pp. ?? 

CH2M Hill, Inc., 1982, Recharge Recovery at Lake Manatee, Phase One: Southwest 

Florida Water Management District, pp. ?? 

CH2M Hill, Inc., 1983a, Progress report for recharge-recovery at Lake Manatee, Phase 

II, Southwest Florida Water Management District, pp. ?? 

CH2M Hill, Inc., 1983b, Progress report No 2 for recharge-recovery at Lake Manatee, 

Phase II, Southwest Florida Water Management District, pp. ?? 

CH2M Hill, Inc., 1984a, Recharge-recovery at Lake Manatee, Phase II, Southwest 

Florida Water Management District, pp. ?? 

CH2M Hill, Inc., 1984b, Operation manual for recharge-recovery at Lake Manatee: 

Southwest Florida Water Management District, pp. ?? 

Corral Jr., M.A., 1983, Distribution of selected chemical constituents in water from the 

Floridan aquifer, Southwest Florida Water Management District: U.S. Geological 

Survey, Water-Resources Investigations Report 83-4041, 1 pp. (Map). 

Department of Environmental Regulation, May 1981, Final Report to the Environmental 

Regulation Commission on the proposed reclassification of the Manatee River 

and other tributaries to Lake Manatee from Class III to Class I-A; State of Florida 

Department of Environmental Regulation. 

Duerr, A.D., J.D. Hunn, B.R. Lewelling, and J.T. Trommer, 1988, Geohydrology and 

1985 water withdrawals of the aquifer systems in southwest Florida, with 

emphasis on the intermediate aquifer system; U.S. Geological Survey, Water- 

Resource Investigations Report 87-4259, 115 pp. 

Gee and Jenson, Inc., 1981, Evaluation of water requirements and consumptive use 

proposed (for) Estech-Duette mine, Manatee County Florida: Manatee County 

Utilities, pp. 40. 

Gee and Jenson, Inc., 1981, Lake Manatee watershed water resource evaluation, 

Phase I - Baseline analysis of existing watershed: Manatee County, pp. 105 

w/figures & tables. 

Gee and Jenson, Inc., 198?, Lake Manatee watershed water resource evaluation, 

Phase II - (Well completion Report) Safe yield and impact assessment: Manatee 

County Utilities Department, pp. ?? 

Gee and Jenson, Inc., 1983 (December 27), Lake Manatee safe yield analysis, 

Manatee County Florida: Manatee County Utilities, pp. ?? 


April 26, 2001 5-18 


Geraghty and Miller, Inc., March 1977, Hydrologic and engineering evaluation f the 

Four River Basins Area, West Central Florida, for Department of the Army, 

Jacksonville District Corps of Engineers. 

Hammett, K. M., 1985, Low Flow Frequency Analysis for Streams in West-Central 

Florida, U.S. Geological Survey, Water-Resources Investigations Report 84- 

4299, pp. ?? 

Jones, K.C., 1981, Plan of development for Task II recharge/recovery at Lake Manatee 

Phase I: Southwest Florida Water Management District, pp. ?? 

Nguyen, H.T. and R.V. McClean, 1982, Instream Reservoir Yield Analysis, Lake 

Manatee Reservoir: SWFWMD, pp. ?? 

Payne, R.D.G., 1984, Recharge-Recovery at Lake Manatee: Phase II, CH2M Hill for 

SWFWMD. 

Peek, H.M., 1958, Ground-water resources of Manatee County, Florida; Florida Bureau 

of Geology, pp. ?? 

Phillips Petroleum Co, 1976, Assessment of the hydrologic regime, Phosphate mining 

project, DeSoto and Manatee Counties, Florida: Phillips Petroleum Co, pp. ?? 

Russell and Axon, Inc., 1963 (May); Water works project No. 6353-3, Manatee County, 

Florida. Appendix C ? 

Smith and Gillespie, Engineers, Inc, 1971; Engineers Preliminary Report on the Braden 

River Water Supply for City of Bradenton, Florida; Project No. 368-28-01. 

Smith and Gillespie, Engineers, Inc, 1983; Engineers Report on the (Evers Reservoir) 

Braden River Management Study; Bradenton, Florida; Project No. 709-71-05; pp. 

Smith and Gillespie, Engineers, Inc, 1987; Water quality monitoring program for Bill 

Evers Reservoir: 1986 annual summary of water quality and flow data. Prepared 

for the city of Bradenton; 35 pp. 

SWFWMD, 1982, Instream reservoir yield analysis: Lake Manatee; (DRAFT), ?? pp. 

SWFWMD, 1985, Resource evaluation of the proposed Braden River Water 

management land acquisition, Southwest Florida Water Management District, 94 

pp. 

SWFWMD, 1989, Land acquisition evaluation of the Myakka River, Southwest Florida 

Water Management District: SAVE OUR RIVERS Water Management Lands 

Trust Fund, 90 pp. 


April 26, 2001 5-19 


SWFWMD, 1991, Resource evaluation of the proposed Lake Manatee lower watershed 

water management land acquisition: SWFWMD, ?? pp. 

SWFWMD, 1992, Needs and Sources (DRAFT), Southwest Florida Water 

Management District, 322 pp. and appendices. 

SWFWMD, 1995, District Water Management Plan, Volumes I and II, Southwest 

Florida Water Management District, March 1995. 

SWFWMD, 1997, Water Use Demand Estimates and Projections, Southwest Florida 

Water Management District, Resource Projects Department (January 1997), 81 

pp. 

SWFWMD, 1999,Estimated Water Use in the Southwest Florida Water Management 

District, Southwest Florida Water Management District, Resource Projects Department 

(January 1997), 81 pp. 

Steinkampf, W.C., 1982; Origins and distributions of saline ground waters in the 

Floridan aquifer in coastal southwest Florida; US Geological Survey, WRI 82- 

4052; 34 pp. 

Stewart, J.W., 1980; Areas of natural recharge to the Floridan aquifer in Florida, 

Florida Bureau of Geology, Map Series 98, 1 p. 

Stringfield, V.T., 1936; Artesian water in the Floridan peninsula; U.S. Geological 

Survey, Water Supply Paper 773-C, 115-195 pp. 

US Department of Army Corps of Engineers, 1971, Survey report on Manatee and 

Braden Rivers, Florida; US Department of the Army Corps of Engineers, 14 pp. 

plus figures and appendices. 

Wanielista, M.P., 1989; Evers Reservoir Hydrologic Study. University of Central 

Florida, Orlando, 139 pp. 


April 26, 2001 5-20 


Chapter 6 

6.0 NATURAL SYSTEMS 


As discussed in Chapter 2 (“Manatee River Watershed Description”), environmental 

issues related to the watershed are the product of human impacts within the area. The 

watershed has undergone significant alteration of its original habitats (e.g., forested 

uplands, wetlands) to its present day mixture of urban, agricultural, mining, and relic 

intact biological communities This pattern of land conversions and its requisite 

infrastructure elements (e.g., roads, utilities, etc.) will continue to shape conditions 

within the remaining natural systems of the Manatee River watershed. 

As land is developed to serve human needs, the size, condition, distribution, and 

abundance of biological communities (e.g., uplands and wetlands) are inevitably and, 

in many cases, permanently altered. Declines in water quality and wildlife populations 

are often in direct correlation to the amount of land development. As these changes 

and losses become pronounced, ecosystem conditions, functions, and values are 

diminished. These changes are typically slow due to the incremental, piecemeal 

alteration of a watershed’s ecosystem, and changes sometimes go unnoticed for 

decades. This watershed management plan acknowledges previous impacts as well as 

recognizes the potential for future degradation of the watershed unless prudent, 

ecosystem based management decisions are made and implemented to ensure the 

ecological viability of the region’s natural systems. 

Additional degradation of ecosystem functions will occur as more natural lands are 

altered for various development purposes (e.g., housing, farming, mining, etc.). 

Without prudent management of the resource, the watershed will continue to 

experience reductions in biological diversity, habitat quality, and the abundance and 

distribution of most native species. In addition, improper management will continue to 

fragment habitats (as compared to intact, functional habitats within a larger ecosystem) 

and shrink and/or destroy wildlife corridors for wildlife movements. Critical habitat 

areas and listed species protection are of highest priority. The importance of proper 

ecosystem management, of maintaining ecosystem functions and sufficient availability 

of quality habitats has been robustly discussed and advocated by scientific and 

governmental circles since the 1970s (e.g., Simon 1974; Tampa Bay Regional Planning 

Council 1986; Drew et al.1987; Lewis and Estevez 1988; Southwest Florida Water 

Management District 1988,1992; Tampa Bay National Estuary Program 1996; Greening 

et al. 1997; Henningsen et al. 1997; Moores 1997). Exhaustive discussions and 

publications have touted the merits of the habitats comprising the ecosystem of Tampa 

Bay and its sub-basins within the larger estuarine watershed. Although not always 

definitively quantifiable, no one doubts the value of the area’s seagrass beds, intertidal 

marshes and mangrove forests, freshwater wetlands, and uplands, where “value” is 

defined along a continuum from economic harvest (e.g., pink shrimp) to pure aesthetic 

pleasures. As such, identification of problems threatening the ecosystem and solutions 

Manatee River CWM Plan 

April 26, 2001 6-1 

Chapter 6 - Natural Systems

addressing those problems is paramount for the long term viability of the area’s 

economy and natural systems. 

In a watershed characterized by increasing population growth and development, even 

areas already under the protective status of public conservation lands are at risk. 

Public conservation lands are often threatened by adjoining land uses and 

development, high intensity and consumptive uses of natural resources, recreational 

uses, and as targets to support infrastructure features such as utility lines, roads, etc. 

Without limitations and prohibitions on uses incompatible with natural resource 

protection, and renewed support and actions to protect their conservation status and 

value, natural resources within these lands are threatened. 

Water quality and water supply (well fields and their management) can have 

pronounced impacts on natural systems. Water quality is influenced by a myriad of 

factors such as atmospheric deposition, surface application of chemicals (fertilizers, 

pesticides, etc.), industrial discharges, and stormwater runoff. Surface water and 

groundwater supply development have the potential to adversely affect surface water 

systems (the Manatee River and tributaries, lakes, wetlands and the Tampa Bay 

estuary). Water diversions, impoundments, aquifer withdrawals, and other 

redistributions interplay with the total water budget for the area, a water budget that 

originates with a variable hydrologic cycle. In an attempt to understand and properly 

manage water quality and volumes within the river, SWFWMD currently is attempting to 

develop and implement “minimum flow levels (MFLs)” for the Manatee River, a critically 

important water management tool that could help preserve the ecological viability of the 

watershed (Flannery 1997). 

The importance of water volume and purity (both spatially and temporally) is widely 

recognized for Tampa Bay, its rivers and tidal creeks, and the biological communities 

that use these systems (e.g., Tampa Bay Regional Planning Council 1987; Lewis and 

Estevez 1988; Browder 1991; Zarbock 1991; Clark 1991; Tampa Bay National Estuary 

Program 1996; Estevez and Marshall 1997). Freshwater flows are critical to the 

ecological health of freshwater wetlands as well as Tampa Bay. Wildlife depends on 

these freshwater flows to meet life requirements. All human and ecosystem needs 

depend upon the same water budget, but humans increasingly are changing the natural 

fluctuations of the historical water budget. With recognition of the significant 

relationships between water quality and water supply in affecting natural resources, the 

reader is directed to the “Water Quality” and “Water Supply” sections of this 

management plan for specific details concerning these two parameters. 

Proper management of the area’s resources can be assured by implementation of the 

process known as “normative forecasting”. Normative forecasting involves defining a 

proposed future reality and then what steps must be taken to create that reality. 

Defining that reality is part of this management plan; a minimum of a 100 year 

timeframe is not unreasonable for planning purposes. For the Manatee River 

watershed, “big picture” decisions will have to be made on what, where, and how much 

of our natural systems should exist for our future reality. Once decided, the path 

necessary to reach that future must be carefully plotted and then followed. With 


April 26, 2001 6-2 


ecognition that humans are part of the ecosystem, one hopes that wise decisions will 

balance the needs of people with those of other life within the ecosystem. Through 

holistic planning and management, the needs of the public and the ecosystem can be 

successfully balanced in perpetuity. 

This plan’s ecosystem approach is complementary with FDEP’s ecosystem 

management program for Florida’s natural resources. In addition, similar strategies 

have been developed and are being implemented through the Tampa Bay National 

Estuary Program (1996) and their “Comprehensive Conservation and Management 

Plan for Tampa Bay”, a resource based management plan. Because of human use of 

the resources, “total ecosystem management” should be implemented to protect and 

manage resources for humans and wildlife. “Total ecosystem management” means that 

all variables influencing the ecosystem must be taken into management consideration, 

inclusive of human populations. Total ecosystem management should be based on the 

targeted carrying capacity of the environment for both humans and wildlife. 

6.2 Summary of Literature Reviewed 

The Manatee River and the associated natural systems within its watershed have been 

broadly described in a variety of publications including: agency project assessments, 

land acquisition reports, general references, government planning reports, Greenways 

workshop reports, ecological assessments and private consultant reports. Many of 

these publications cover only select areas of the watershed and limited sections of the 

Manatee River or its tributaries. Conditions, problems and issues raised in many of 

these reports are similar and are often applicable to most areas within the watershed; 

however, few reports treat the entire watershed and natural systems issues in an 

integrated or comprehensive manner. Information is often project specific and limited in 

scope, time frame and locality. 

The following narratives summarize publications concerning the natural systems of the 

Manatee River watershed. Literature was gleaned from SWFWMD, FDEP, Manatee 

County, and personnel contacts. Several of the reports identify problems and issues 

affecting natural systems within portions of the watershed. All reports cited here may be 

found in the SWFWMD library in Brooksville, Florida. As evidenced from this list of 

publications, relatively little is documented for the Manatee River Watershed; of 

particular note is that ecosystem level information is wanting. Baseline research needs 

to be performed on the status of the ecosystem and on plant and animal populations of 

the region. The majority of published information was in the form of environmental 

impact statements concerning proposed developments within the watershed, many of 

which have not been included below due to their limited value and site specificity. 

Conservation Consultants, Inc. 1972. An Ecological Study in the Vicinity of Port 

Manatee Tampa Bay, Florida. 

This study continues a program sponsored by Florida Power and Light Company to 

describe and evaluate the marine environment in the Port Manatee vicinity prior to the 

construction of a steam electric generating station. It includes investigations conducted 

from December 1971 to March 1972. 


April 26, 2001 6-3 


DeGrove, Bruce D. 1986. Manatee River Water Quality Based Effluent Limitation 

Documentation. Bureau of Water Quality Management. 

This study was based on a two-dimensional dynamic estuary model used to develop 

effluent limits for present and proposed discharges to the estuarine portion of the 

Manatee River. 

Edwards, Randy E. 1992. City Island Habitat Restoration Fish and Invertebrate 

Monitoring. Mote Marine Lab. Tech. Rept. Number 277. 

Fishes and large invertebrates were monitored from January 1991 to April 1992, in 

order to assess the impact and value of a habitat restoration project (1.8 ha of restored 

intertidal wetlands and newly created saltwater ponds) on City Island in Sarasota. 

Edwards, Randy. 1992. Identification, Classification, and Inventory of Critical 

Nursery Habitats for Commercially and Recreationally Important Fishes in the 

Manatee River Estuary System of Tampa Bay. Mote Marine Laboratory, Sarasota, 

Florida. SWFWMD Library QL615 S6. 

This scientific study summaries a fisheries evaluation of (primarily) nursery use of 

Manatee and Braden River habitats for commercially and recreationally important 

fishes of the Tampa Bay ecosystem. The author sampled seasonally at various 

locations within the rivers using seines and collected various standard physicochemical 

data. The study classifies habitats and provides catch data by species per 

habitat. The study concluded that the Manatee and Braden River estuarine habitats 

are very important nursery grounds for many commercially and recreationally important 

fish species. 

Florida Department of Environmental Resources. 1981. Final Report to the 

Environ-mental Regulatory Commission on the Proposed Reclassification of the 

Manatee River and Other Tributaries to Lake Manatee from Class III to I-A. 

SWFWMD Library GB1227 M3 F5. 

This report primarily summarizes an application to reclassify portions of the Manatee 

River to a drinking water designation. The report provides limited descriptions of 

ecological resources and land uses. Some water quality data is provided. 

Florida Power & Light Company. 1976. Development of Regional Impact, 

Application for Development Approval Keentown - Whidden 240KV Transmission 

Line. 

This DRI was required for a 37 mile long, 240 KV transmission from the Keentown 

Substation in Manatee County to the Whidden Substation in DeSoto County. Potential 

effects and impacts of the project are addressed from an environmental and economic 

standpoint. 

Manasota-88. 1988. Project Manasota-88 Report of an Environmental Health 

Study 1966-68. SWFWMD Library HC79 E5 M3. 

This report is an early summary of planning and environmental problems of Manatee 

and Sarasota Counties. The volume addresses water supply, water pollution, sewage 

and sewage treatment problems, solid waste, air pollution, housing, recreation, 


April 26, 2001 6-4 


sanitation, public health laws, and recommendations. The volume has very little 

concerning natural systems although the tone recommends humans need to reduce 

impacts to natural systems and not pollute the area’s air and water resources. 

Manatee County Environmental Action Commission. 1993. Emerson Point 

Management Plan. 

This plan is a statement of policy and direction for the long-term management and 

protection of this 195-acre state owned CARL site, which is managed by Manatee 

County for recreational, habitat and archaeological purposes. 

Manatee County Environmental Action Commission. 1993. Evers Reservoir 

Watershed Baseline Water Quality Monitoring 1988-1992 Final Report. 

The results of a study conducted to provide baseline information for aiding long range 

resource management of the watershed system, this report details results of water 

quality sampling and analyses within the Evers Reservoir watershed from June 1988 

through June 1992. The project was jointly funded by the Manasota Basin Board and 

Manatee County. 

Manatee County Utilities System. 1980. Report on the Evaluation of Potential 

Impacts of the Proposed Estech Duette Mine on Lake Manatee & and Manatee 

County Water Treatment Plant. 

This report provides information on the behavior of clays in the natural water system, 

clay contamination in the treatment process, chemical constituents to be expected in 

the discharge, and expected impacts from normal operation of the mine. 

Morris, Julie. 1974. An Ecological Study of Upper Myakka Lake - With a Special 

Focus on Hyacinth and Hydrilla. New College, Sarasota, Fla. 

Under this study, the geography and development of the Upper Myakka Drainage Basin 

and Upper Myakka Lake are described to pinpoint sources of nutrient enrichment from 

natural and artificial sources. The report concludes with recommendations for 

management and control of aquatic plants to retard eutrophication in the Lake. 

Morton, Henry W. 1977. Radiological Impact Assessment of the Four Corners 

Mine. W. R. Grace & Company. 

Ground-water monitoring for radium was included in this report which documents the 

results of an evaluation of the potential radiological health impact of the proposed mine 

on the public in Hillsborough and Manatee counties. The report emphasizes the 

benefits of the mining activity and categorizes the radiological impact as acceptable 

risks. 

Peek, Harry M. 1958. Ground-water Resources of Manatee County, Florida. U.S. 

Geological Survey. 

This was a study of the geology and ground-water resources of Manatee County, 

primarily consisting of collecting and evaluating data from more than 900 private and 

public wells to determine if salt-water intrusion had occurred or was likely to occur. 


April 26, 2001 6-5 


Sarasota County Environmental Services Laboratory. 1989. Air Quality 

Management Annual Report. 

This report is a year-end summary of air program activities including open burning 

permits, Stationary air pollution source permitting, Mobile source air pollution control, 

asbestos abatement, air toxics control, and inspection, compliance and enforcement of 

these activities. 

Southwest Florida Water Management District. 1984. Manasota Basin Literature 

Assessment Study. SWFWMD Library Z7164.W2. 

This is an annotated bibliography of literature available up to 1984 for planning and 

ecological publications for Manatee and Sarasota Counties. Summaries are short but 

literature summarized includes topics such as ground water, DRIs and other 

developments. The volume has very minimal information on natural systems, with most 

reports dealing with summaries of proposed or existing developments. 

Southwest Florida Water Management District. 1991. Resource Evaluation of the 

Proposed Lake Manatee Lower Watershed Water Management Land Acquisition. 

Surface water, ground water and environmental conditions within the project area are 

discussed, as well as the general effects of land use activities within the surrounding 

watershed areas. The study area encompasses the three original proposed acquisition 

areas in the “SOR Five-Year Plan” and a proposed expansion area or 30% of the total 

Lake Manatee watershed. 

Southwest Florida Water Management District. 1995. Manatee County Integrated 

Plan. SWFWMD Library G13657 S656. 

The plan identifies and evaluates key water resources management issues within 

Manatee County. The plan is supposed to be used as a tool to foster integration of 

land use planning and growth management activities. The plan covers water 

management supply issues, flood protection, water quality, and some natural system 

issues. Concerning natural systems, the plan identifies the SWFWMD’s SWIM effort 

in Manatee County, noting Peanut Lake, Terra Ceia Aquatic Preserve, two Braden 

River sites, and Sarasota Bay. The volume provides cursory “Natural System 

Implementation Strategies”. 

Southwest Florida Water Management District. 1997. Save Our 

Rivers/Preservation 2000 Five Year Plan 1997. 

Plan which is updated annually details lands within the District, including the Manatee 

River watershed which are within the study area, acquired by the District or other public 

agency, or proposed for acquisition by the District in fee or by a lesser interest. 

Includes maps, description of lands, importance to water management, reasons for 

acquisition, recreational potential and acreage breakdown by project. 

Tampa Bay National Estuary Program. 1996. Charting the Course for Tampa Bay 

- the comprehensive conservation and management plan for Tampa Bay. TBNEP. 

U. S. EPA. 

This comprehensive resource based management plan summaries the most important 

problems facing the Tampa Bay estuary, inclusive of freshwater inflows, stormwater, 


April 26, 2001 6-6 


dredge and fill, urbanization, and habitat quality. Solutions to meet goals are carefully 

delineated and responsible parties identified that will implement portions of the plan. 

This plan was crafted and is being implemented by the public and local governments of 

the Tampa Bay watershed. 

U. S. Army Corps of Engineers. 1971. Survey Report on Manatee and Braden 

Rivers, Florida. SWFWMD Library GB1399 U565. 

This report is a study for flood control of the Manatee and Braden River areas, 

providing very limited ecological or land use characterizations. 

U. S. Army Corps of Engineers. 1972. Special Flood Hazard Information Report 

Manatee and Braden Rivers Manatee and Sarasota Counties, Florida. SWFWMD 

Library GB1399.4 M3 U52. 

This volume summarizes flood zones of Manatee and Braden River areas as of 1972. 

The volume provides no ecological information other than flood zone delineations. 

U.S. Department of Agriculture Soil Conservation Services. 1958. Soil Survey: 

Manatee County, Florida. SWFWMD Library S593 M3 U5 1958. 

U.S. Department of Agriculture Soil Conservation Services. 1972. Supplement to 

the Soil Survey: Manatee County, Florida. SWFWMD Library S593 M3 U5 

Supp. 

U.S. Department of Agriculture Soil Conservation Services. 1984. Soil Survey: 

Manatee County, Florida. SWFWMD Library S593 M3 U5. 

These three volumes provide soil types and distributions for all of Manatee County, 

inclusive of the watershed of the Manatee River. The volumes provide no ecological 

data or any information other than soil types. 

6.3 Available Data 

In addition to the information available in the publications described in the Literature 

Review Section, other information in the form of maps, aerial photographs, GIS data 

bases, consultant reports, model analyses, monitoring records, and field observations 

is available from the following sources. 

6.3.1 Southwest Florida Water Management District 

Geographic Information System (GIS), including regional land use and land cover, 

soils, hydrography, topography, groundwater recharge potential. 

Aerial photographs, maps with contours (land elevations). 

Surface water and groundwater levels (hydrologic data base); monthly values for lakes, 

select wetlands (e.g. marshes, swamps), rivers and streams (stage elevation and 

discharge values). 


April 26, 2001 6-7 


Regional wetland monitoring system (select wetland stations: qualitative and 

quantitative 

vegetation data; general wildlife observations). 

Consultant reports submitted as part of permit conditions (e.g. wetlands monitoring for 

water levels, hydroperiods, vegetation composition and abundance, and wildlife use). 

Surface Water Improvement and Management (SWIM) Program: research studies, 

restoration sites project reports and inventories, water quality monitoring and model 

analyses, consultant reports, etc. 

6.3.2 Department of Environmental Protection 

Florida Natural Areas Inventory (FNAI) site-specific records of floral and faunal 

occurrences including listed species records, assessment of local and regional 

importance; part of the Natural Heritage Program; information regularly updated. In 

addition, the Florida Marine Research Institute has qualitative and quantitative 

mapping/data of various resources such as seagrass beds, manatee populations, 

fisheries species, etc. 

6.3.3 Florida Game and Fresh Water Fish Commission 

Game species inventories; Fisheries Reports (population estimates). 

Wading Bird Atlas (inventory of rookeries) 

Non-Game Species Program (species inventories; listed species information, eagle 

nests) 

Florida Breeding Bird Atlas (all species): Extensive surveys to confirm breeding status 

in all counties of the state (at various levels). Data collected and compiled at the U.S. 

7.5 Quadrangle Map level. Atlas not yet published (in progress), data are available. 

6.3.4 U.S. Fish and Wildlife Service 

National Wetlands Inventory (wetland maps, classification, acreages). 

6.3.5 Miscellaneous 

Audubon Society Christmas Bird Counts (published in: American Birds); Environmental 

Management Department of Manatee County has benthic data and limited fisheries 

data for the river as well as vegetation maps of the lower reaches of the river; City of 

Bradenton has habitat mapping from the Evers Dam to the river’s mouth. 

6.4 Permitting Issues 

Regulatory and permitting issues of major interest and importance for the Manatee 

River watershed include: 


April 26, 2001 6-8 


1. Regional potable water supply development (groundwater withdrawals: balancing 

increasing demands with available supplies and potential adverse impacts to 

wetlands and other surface water systems). SWFWMD special orders and 

WUCA’s designation, pending rule challenges and other litigation. 

2. Designation of corridors for linear facilities (i.e. roads, utility lines: gas, water, 

electric, sewage) for reduction of adverse environmental impacts. 

6.5 Land Acquisition for Resource Protection and Conservation 

6.5.1 Conservation and Recreation Lands Program (CARL) 

FDEP’s Conservation and Recreational Lands (CARL) program has long been Florida’s 

major public environmental land acquisition program for the protection and 

conservation of Florida’s natural heritage. Originally funded solely by mineralextraction 

severance taxes and documentary stamp fees, the creation of Preservation 

2000 provided financial stability for the program. The Florida Parks Service operates 

the Lake Manatee State Recreation Area, which consists of 556 acres located along 

the southern shore of the lake. Lastly, the Emerson Point property was purchased via 

the CARL program. 

6.5.2 Save Our Rivers Program 

The Save Our Rivers (SOR) program is financed by the Water Management Lands 

Trust, administered statewide by FDEP and regionally implemented by the Southwest 

Florida Water Management District since 1981. In Lake Manatee Lower Watershed, 

approximately 2,137 acres have been acquired by the SWFWMD to date. Originally, 

the acquisition consisted of three separate parcels in the vicinity of the Lake Manatee 

reservoir. These lands included portions of Boggy Creek, Gilley Creek, Fort Crawford 

and Little Fort Crawford Creeks - all tributaries to the Manatee River. As a result of a 

water resources study, the project was expanded to include additional lands in the Lake 

Manatee Lower Watershed. Under SWFWMD’s 1998 Five-Year Plan for Land 

Acquisition, 19,230 acres are proposed for purchase as expansions and connections to 

existing preserve lands in Lake Manatee Lower Watershed, inclusive of the 5882 acre 

Rutland Ranch.. 

6.5.3 Preservation 2000 

Preservation 2000 (P2000) is a ten-year, $3 billion land acquisition program approved 

by the Florida Legislature in 1990. P2000 strengthens and supplements most of 

Florida’s existing land acquisition programs, and by forging partnerships with private 

and public agencies (e.g. Nature Conservancy, local governments) makes funds 

available for a wide range of land acquisition and conservation purposes. When 

appropriate, P2000 funds will be applied to support and complement SOR acquisition 

projects within the Manatee River watershed. In fact, all District-owned lands in the 

Lake Manatee Lower Watershed were purchased with P2000 funds to date. In the 


April 26, 2001 6-9 


SWFWMD’s, Preservation 2000 Remaining Needs and Priorities, 18,504 acres are 

proposed as high SOR fee priority. 

6.5.4 Manatee County 

Some 20,000 acres in the upper watershed, now known as Duette Park, have been 

purchased by the County. The Manatee County Environmental Lands Management 

and Acquisition Committee (ELMAC) has pursued CARL assistance for purchase of 

several tracts within Manatee County (i.e., Emerson Point). In addition, ELMAC has 

developed a priority list of parcels targeted for acquisition (Map 16, Manatee River 

CWM Map Atlas). 

6.5.5 Florida Communities Trust 

The Florida Communities Trust, established by the state legislature in 1989, assists 

local governments in meeting the natural resource protection requirements of Florida’s 

Growth Management Act (Chapter 163, Part II, Fla. Stat.). The trust operates within the 

Florida Department of Community Affairs (FDCA) as a non-regulatory agency. It 

provides monies through loans and grants (including matching funds) for land 

acquisitions that further the goals of the conservation, recreation, open space, and 

coastal elements of local government’s comprehensive plans. To date, Manatee 

County has been successful in obtaining matching funding from the Florida 

Communities Trust for approximately 2,216.80 acres known as the Manatee 

Headwaters at Duette, and have submitted three applications in 1998 for approximately 

40 acres. In addition, the ca 1700 acre Boggy Creek site has been approved for 

acquisition as a mitigation bank for the County. Given that the Manatee River is 

recognized as a resource protection area, Manatee County is encouraged to continue 

to pursue funding for acquisition and habitat restoration. 

6.5.6 Nature Conservancy 

The Nature Conservancy (TNC) is a nonprofit international organization which works to 

conserve biological diversity through habitat conservation. The Nature Conservancy, 

working with Natural Heritage Inventory scientists and other researchers to set 

conservation priorities, acquires lands for conservation management. 

TNC also uses land exchanges, conservation easements, retained life estates, and 

other arrangements to work with landowners to accomplish habitat protection. Some 

tax benefits may be available. While TNC cannot act as legal or tax advisor to 

landowners, the organization has attorneys on staff who will work with landowners' 

counsel to help land owners achieve their conservation objectives. 

TNC also works with private landowners to provide technical assistance on the 

identification and management of natural resources such as rare species and unusual 

natural communities. Cooperative management agreements can be flexible in content 

and can be canceled. 


April 26, 2001 6-10 


6.5.7 Trust for Public Lands 

The Trust for Public Land (TPL) is a national nonprofit land conservation organization 

founded to protect land for the public’s use and enjoyment. Its principal goal is to 

acquire lands suitable for open space and parks and convey them to public agencies 

for ownership and management. Additionally, TPL provides training and technical 

assistance to private landowners, local land trusts, and government agencies to 

enhance their land conservation goals. 

6.6 Alternative Initiatives for Natural Resources Protection 

In addition to the various federal, state and local regulatory programs that attempt to 

impose protection over the various natural resources of the Manatee River watershed, 

several initiatives (most of them of recent vintage) have emerged; and they are 

attempting to enhance protection and management of the watershed’s natural 

resources by broadening, improving, developing and integrating management and 

protection options. These regional and local programs are complementary with various 

federal programs and laws (i.e., Endangered Species Act, Clean Water Act, U. S. Army 

Corps of Engineers permitting program). 

6.6.1 State Management Programs 

1) Florida Greenways Program 

2) Department of Environmental Protection - Ecosystems Management 

Program: Manatee River Ecosystem Management Program (pilot project) 

3) Southwest Florida Water Management District: - Comprehensive 

Watershed Management Program (CWM): Manatee River Watershed 

Project 

4) Department of Community Affairs: 

DCA guides growth and development throughout the state by administering 

implementation of local government comprehensive planning to encourage 

the most appropriate use of land and water resources. 

5) Agriculture Clean Water Program 

Recently, agricultural impacts upon water quality have been gaining 

considerable attention. In October 1981, the State Department of 

Agriculture and Consumer Services became the lead agency to implement 

the agricultural element of Florida’s Water Quality Management Plan. 

Other agricultural agencies involved in implementing the Agriculture Clean 

Water Program include the local Natural Resource Conservation Agency. 

Through the cooperative efforts of agricultural landowners and these 

agencies, farm lands will be managed through conservation plans which 

consider water quality along with productivity and cost effectiveness. 


April 26, 2001 6-11 


6.6.2 State Regulation Programs 

1) The State Stormwater Rule, Chapter 62-25 

Outstanding Florida Waters 

The Outstanding Florida Water (OFW) designation was developed to 

provide additional protection to special waters recognized for their 

exceptional ecological and recreational significance. Special Protection, 

Outstanding Florida Waters, Section 17.3041 F.A.C., is a listing of certain 

surface waters, such as waters in the State Park System and Aquatic 

Preserves in addition to designated special waters. It is the FDEP’s policy 

to afford the highest protection to these waters. These policies are 

implemented through the application of additionally restrictive criteria by 

which FDEP issues permits. In general direct discharges to an OFW 

cannot lower ambient water quality in the year prior to designation while 

indirect discharges cannot significantly degrade the OFW. These 

provisions are predicated on the antidegradation concept that degradation 

should not occur except after full consideration of the consequences and 

then only to the extent necessitated by desirable economic and social 

development. 

6.6.3 County and Municipal Programs 

1) Manatee County Comprehensive Plan: Provides future land use planning 

for the County. 

2) Tampa Bay National Estuary Program: The County was and is an active 

participant in the drafting and implementation of the TBNEP’s Comprehensive 

Conservation and Management Plan for Tampa Bay. 

3) Manatee County Environmental Management Department: Responsible for 

helping protect and manage the County’s environmental resources. 

4) Comprehensive Plans for the Cities of Bradenton and Palmetto: Provides 

future land use planning for these two municipalities. 

6.7 Minimum Flows 

The District's current Minimum Flows and Levels (MFL) program can be divided into 

three components, including the establishment of (1) minimum flows for streams, rivers 

and other flowing watercourses, (2) lake levels and (3) ground water levels. The term 

minimum flow refers to the limit in a watercourse at which further withdrawals would be 

significantly harmful to the water resources or ecology of an area. Similarly, "minimum 

water level" is statutorily defined as the level of ground water in an aquifer or surface 

water (e.g., a lake) at which further withdrawals would be significantly harmful to the 

water resources of an area. Both minimum flows and levels are to be based on "the 


April 26, 2001 6-12 


est information available" (373.042, F.S.). The District proposes to establish minimum 

flows for the Manatee River at the dam by the year 2005. 

The SWFWMD approach to managing withdrawal-related impacts to streams and other 

flowing watercourses involves two management components: 

1. Allowable withdrawal rates are established in water use permits that specify 

volumes of water that can be removed from a stream or other surface 

watercourse over various time intervals. These quantities are typically expressed 

as average daily and maximum daily rates of withdrawal. 

2. Regulatory minimum flows are established at which withdrawals must cease so 

as not to cause any reduction in flow. Essentially, withdrawals may not reduce 

flows in a watercourse below its minimum flow. 

Since 1977, the District has maintained a program to adopt management water levels 

for lakes throughout the District. The objective of this program is to identify a series of 

water levels representing a healthy range for each lake that can be used for regulatory 

and resource management purposes. As of January 1, 1994, regulatory levels have 

been adopted on 374 lakes in the District. The program also collected related physical, 

hydrologic, and ecological information on many other lakes. Lakes are selected for the 

adoption of levels based on several criteria. Lakes with District water-control 

structures, those with water use permits, and lakes 20 acres or larger are given high 

priority. At present, stage records are regularly measured on 350 lakes with adopted 

levels. These data are used to support District regulatory and environmental programs 

and local government programs concerning land development, floodplain delineations 

and zoning. Efforts are underway to collect regular stage data on remaining lakes that 

have adopted levels. 

The District’s development of minimum ground water levels is intricately tied to ongoing 

Water Resource Assessment Projects (WRAPs). The focus of these efforts is to 

identify and implement safe water yield through a comprehensive approach that 

includes planning, technical analyses and regulation. This is intended to result in an 

integrated, comprehensive strategy for establishment of minimum ground water levels. 

With completion of the SWUCA management plan and subsequent rule making, the 

District proposes to establish minimum ground water levels for part or all of the 

SWUCA. Subsequent ground water levels will be developed as a part of the 

NTBWUCA process and for other parts of the District as safe yield analyses occur. 

6.7.1 Minimum Flows and Levels Approved Priority List and Schedule 

The District, pursuant to Section 373.042 (2) of Florida Statutes, hereby publishes its 

approved Priority List and Schedule for the Establishment of Minimum Flows and 

Levels. The following surface watercourses, aquifers, and surface waters within the 

District were approved by the Governing Board on September 26, 2000, and by the 

Florida Department of Environmental Protection on December 15, 2000. The Priority 

List and Schedule and related information will be updated annually. 


April 26, 2001 6-13 


The Priority List is based on the importance of waters to the state or region, the 

existence of or potential for significant harm to the water resources or ecology of the 

state or region and includes those waters which are experiencing or may reasonably be 

expected to experience adverse impacts. It is the District’s intention to voluntarily 

undertake independent scientific peer review for all waterbodies on the Priority List. 

2001 

• Hillsborough County Lakes (Calm, Hobbs, Starvation, Church/Echo, Crenshaw, 

Cypress, Fairy, Halfmoon, Helen, Ellen, Barbara, Round, Saddleback, Raleigh 

and Rogers) (1) 

• Pasco County Lake (Big Fish) (1) 

• Southern Water Use Caution Area (SWUCA) (Floridan Aquifer) 

• Upper Peace River 

• Tampa Bypass Canal 

• Sulphur Springs 

• Alafia River (includes Lithia and Buckhorn springs) 

• Polk County Lakes (Eagle, McLeod, Wales, and Clinch) 

• Highlands County Lakes (Lotela, Letta, and Jackson) 

2002 

• Pasco County Lakes (Bird, Moon, Linda, Pasadena, Padgett, Parker aka Ann, 

Green, Bell, Clear and Hancock) 

• Hernando County Lakes (Hunters, Lindsey, Mountain, Neff, Spring and Weeki 

Wachee Prairie) 

• Hillsborough County Lakes (Strawberry, Reinheimer, Wimauma, Platt, Mound, 

Allen, Harvey, Charles, Jackson, Garden, Taylor and Dan) 

• Middle Peace River 

2003 

• Citrus County Lakes (Tsala Apopka and Marion) 

• Sumter County Lakes (Panasoffkee, Big Gant, Deaton, Miona and Okahumpka) 

• Polk County Lake (Crooked) 

• Highlands County Lake (Placid) 

• Lower Peace River Estuary System (2) 

2004-2005 

• Intermediate Aquifer (SWUCA) (where deemed technically feasible) 

• Upper Hillsborough River System 

• Weeki Wachee River System 

• Manatee River System 

2006 - 2010 (3) 

• Braden River System 

• Little Manatee River System 

• Middle Withlacoochee River System 

• Upper Withlacoochee River System (Green Swamp) 


April 26, 2001 6-14 


• Lower Withlacoochee River System (Lake Rousseau / Rainbow Springs) 

• Myakka River System 

• Highlands / Polk Surficial Aquifer 

• Anclote River System 

• Brooker Creek 

• Pithlachascotee River System 

• Myakkahatchee Creek (Big Slough) 

2011 - 2015 (3) 

• Crystal River System 

• Homosassa River System 

• Chassahowitzka River System 

(1) 

(2) 

(3) 

Establishment to occur in the first quarter of 2001. 

A “River System” refers to the unique, watershed-based aspect of flowing 

watercourses and may include analysis of springs, tributaries, lakes, wetlands and 

aquifers, as appropriate. 

Lakes during this period will be selected at a later date based on future priorities. 

6.8 Natural Systems: Issues, Strategies, and Actions 

6.8.1 Natural Systems Goals 

The Manatee River watershed is an important component of the Tampa Bay estuarine 

ecosystem. With Tampa Bay receiving intense focus by the public and all levels of 

government (local to federal), the bay has received significant thought on how best to 

restore, preserve, and manage the ecosystem. Accordingly, two major comprehensive 

management plans have been developed that address natural systems of the bay: the 

Tampa Bay Surface Water Improvement and Management Plan (Southwest Florida 

Water Management District 1988, 1992) and “Charting the Course”, the 

Comprehensive Conservation and Management Plan for Tampa Bay (Tampa Bay 

National Estuary Program 1996). While these plans are all inclusive for bay-wide 

issues, this plan is focused just on the Manatee River watershed. Considerable 

overlap exists between all three plans, since natural system issues are widespread 

throughout the Tampa Bay watershed, inclusive of the Manatee River watershed. 

TBNEP listed five goals for the bay involving 1) water and sediment quality, 2) bay 

habitats, 3) fish and wildlife, 4) spill prevention and response, and 5) dredging and 

dredged material management. Complementary to these goals are similar goals 

established by SWFWMD’s SWIM program involving reversing environmental 

degradation, optimizing water quality and habitat values, and providing long term 

management of the resource. 

For this plan, initial natural system goals are global in nature, to be better defined (in 

future updated management plans) when certain actions are implemented addressing 

specific issues detailed in this plan. Specifically, these initial goals for the Manatee 


April 26, 2001 6-15 


River watershed are essentially identical to those defined in the SWIM Management 

Plan for Tampa Bay. Issues, strategies, and actions delineated here, once 

implemented, will achieve the following goals: 

1. To reverse the environmental degradation of the Manatee River watershed. 

2. To optimize water quality and other habitat values, thereby promoting the 

sustained existence or re-establishment of thriving, integrated, biological 

communities. 

3. To ensure the maintenance ad infinitum of a productive, balanced ecosystem 

complementary with human needs and uses of the resource. 

To meet these natural system goals, seven issues have been identified and actions 

defined on how best to address the watershed’s needs. The seven issues include: 

1) Habitat loss, alteration, and fragmentation 

2) Public access and recreation 

3) Public education 

4) Urbanization and agricultural encroachment 

5) Pollutant loading (inclusive of subissues of a) agricultural chemical use and 

runoff; b) animal waste management; c) sewage treatment and discharges, 

inclusive of sludge disposal; d) air quality and atmospheric deposition; e) 

stormwater runoff) 

6) Polluted sites and hazardous wastes (inclusive of subissues of a) superfund 

and known polluted sites; b) hazardous waste generation and disposal) 

Issue #1: Habitat Loss, Alteration and Fragmentation 

Background: Land development throughout the watershed has and will continue to 

produce adverse environmental impacts for the area’s ecosystem. Currently, an 

estimated 35% of the historical ecosystem remains, with 65% of the watershed having 

experienced some form of development (Maps 2, 14, and 19; Manatee River CWM Map 

Atlas). The historical ecosystem of the watershed increasingly is being degraded and 

fragmented, resulting in loss of habitats critical to the success of various wildlife 

populations. This issue is the most critically important issue of the seven concerning 

the natural systems of the Manatee River watershed. Special emphasis should be 

placed on timely implementation of actions recommended for this issue. 

Strategy: Protect remaining natural systems and their functions within the watershed 

through land acquisition (fee simple) and other land conservation methods (e.g., less 

than fee acquisition, conservation easements, land management, etc.). High quality 


April 26, 2001 6-16 


natural areas are a priority, particularly for establishing and/or maintaining wildlife 

corridors and areas of high biodiversity and biological importance. Of importance is the 

coordination of all levels of programs (local, state, regional, federal) striving to 

implement this strategy; coordination is essential to eliminate redundancy and 

maximize successful strategy implementation. Land acquisition also should include 

parcels in need of restoration. Proper management of existing and acquired lands 

must be made a priority to insure coastal habitats are as productive and viable as 

possible. Acquisition and proper management of those tracts should be the top priority 

of the natural systems issues. Successful implementation of this strategy is regarded 

as the most valuable of all the strategies towards meeting natural system goals. 

Actions: 

1. Update the identification and inventory of historical vs. current habitat 

distributions throughout the watershed to determine relative habitat losses by 

habitat type and quality of existing habitats. 

2. In correlation with updated habitat mapping, baseline research must be done 

within the watershed to document existing wildlife populations and distributions. 

Wildlife populations often can be directly correlated with sizes and distributions 

of functional habitats. As such, habitat protection and restoration acreage 

should be based on managed carrying capacity goals (see “habitat restoration” 

strategy below) complementary with water quality and water supply goals. 

Normative forecasting should be implemented to reach long term (at least 100 

years) goals. At a minimum, land acquisition and protection must be adequate 

to maintain existing wildlife populations. Wildlife assessments are needed to 

determine if habitats are lacking for species, thereby giving guidance as to what 

habitats should be prioritized for acquisition and/or restoration. Habitat diversity, 

abundance, and distribution is of paramount importance for the long-term 

success of wildlife populations. Consideration should be given for use of 

“indicator species” as benchmarks for wildlife populations within the watershed, 

a resource based management approach adopted by the TBNEP in their CCMP. 

As an alternate approach, consideration could be given to just target acreages 

desired per habitat type (i.e., uplands, wetlands, etc.), allowing wildlife 

populations to stabilize within those acreages. 

3. In coordination with regional and state acquisition programs (e.g., Preservation 

2000, Save Our Rivers, etc.), identify and prioritize lands targeted for 

acquisition, inclusive of establishing/maintaining “greenbelts/green webs”, 

wildlife corridors, and wildlife carrying capacity goals (as discussed in #2 above). 

Prioritization should be based on weighted rankings using information about 

each site secured from the public and professionals (ecologists, planners, land 

managers, etc.). Additional guidance concerning site characteristics and 

potential ranking criteria should be secured from: Florida Game and Fresh 

Water Fish Commission’s “Closing the Gaps” report and maps; Florida Natural 

Areas Inventory data; TBNEP’s “Charting the Course” management plan and 

their “Setting Priorities from Tampa Bay Habitat Protection and Restoration: 


April 26, 2001 6-17 


Restoring the Balance”. Normative forecasting should be employed when 

implementing this action with at least a 100 year window, using a balanced 

approach to provide diverse habitats necessary for various wildlife populations. 

4. After identification and prioritization of lands targeted for acquisition, purchase 

lands as expeditiously as possible. With acquisition must come the commitment 

to properly manage parcels. Though site specific, individual management plans 

may be necessary for differing parcels, inclusive of habitat restoration. With the 

goal of establishing and maintaining “greenbelts/green webs” will come the 

opportunity to manage the resources as an ecosystem. 

5. Explore, develop, and implement alternatives to land acquisition to meet strategy 

goals of preserving ecosystem functions within the watershed. Among others, 

pursue: a) conservation easements and other less-than-fee instruments to 

secure protection of the ecosystem and/or establishment of greenbelts and 

wildlife corridors; b) transfer of development rights; c) promotion of 

environmentally creative development designs (e.g., clustering building units, 

more preserve areas within developments, reduced densities, increasing 

setback requirements, etc.); d) changes in the tax codes to provide incentives to 

landowners/developers who protect and manage natural habitats, inclusive of 

habitat enhancement and restoration efforts. 

6. Educate private landowners about protection, management, and 

enhancement/restoration of habitats and provide assistance as appropriate 

(inclusive of exotic plant management). 

7. Support efforts of ELMAC and a funded Manatee County land acquisition and 

management program. 

Participants: USFWS, USACE, FDEP, SWFWMD, FGFWFC, Manatee County, 

municipalities, environmental organizations (e.g., National Audubon, Tampa 

BAYWATCH, etc.) 

Strategy: Conduct habitat enhancement, restoration, and creation projects to restore 

lost and degraded habitats within the ecosystem with the goal of providing adequate 

habitats (complementary to preservation lands) to maintain viable wildlife populations 

within the watershed; post-project management is critical to the long term success of 

habitat functions. Habitat projects should be patterned after the “habitat mosaic” and 

“restoring the balance” philosophies/practices of SWFWMD’s SWIM program and the 

TBNEP. For purposes of simplification, hereafter any reference to habitat “restoration” 

will be synonymous with habitat “enhancement, restoration, and creation”. Habitat 

restoration projects should complement all land acquisition and management programs 

detailed in Issue #1 above and also should employ the process of normative 

forecasting. 


April 26, 2001 6-18 


Actions: 

1. Identify habitat goals (see “land acquisition” above) for the watershed and 

coordinate these goals with land acquisition and management programs; habitat 

goals should include acreage and distributions of all coastal habitats necessary 

to insure viable wildlife populations (i.e., “ecosystem restoration” and 

maintenance). In essence, the managed carrying capacity of the watershed for 

target populations should be defined and goals set to preserve and/or achieve 

steady-state habitats/populations (e.g., acres of pine flatwoods, freshwater 

wetlands, xeric scrub, seagrasses, numbers of cattle egrets, sandhill cranes, 

gopher tortoises, large mouth bass, deer, osprey, etc.). As a component of 

habitat goals, exotic plant and animal species must be addressed; due to the 

area and range of exotic species problems, a separate plan may need drafting to 

deal with the problem. Defining the managed carrying capacity of the watershed 

will require baseline research (new and/or literature review of previous data) and 

should include a carrying capacity of the region for humans. 

2. Identify and prioritize habitat restoration sites; although public lands are 

envisioned as the primary project sites, as appropriate, private sites (pending 

landowner’s permission) should be included if project safeguards can be met 

(e.g., conservation easements, public benefit, etc.). 

3. Coordinate with private interests and local, state and federal 

governments/agencies to implement restoration projects, recognizing that postproject 

management is critical to the long term success of the habitat project. 

4. Complementary to annual local, regional, and state funds, secure permanent 

funding sources for habitat restoration projects and management. 

5. Where feasible and appropriate, encourage regional mitigation banks (both 

public and private) to complement habitat restoration projects. 

6. Development monitoring programs to evaluate the effectiveness of restoration 

and management efforts; as warranted, adjust restoration and management 

efforts to maximize ecosystem functions and wildlife populations. 

Participants: USFWS, USACE, FDEP, SWFWMD, FGFWFC, Manatee County, 

municipalities, environmental organizations (e.g., National Audubon, Tampa 

BAYWATCH, etc.) 

Issue #2: Public Access and Recreation 

Background: Residents and seasonal visitors are attracted to the Manatee River 

watershed because of its aesthetically pleasing environments, wildlife populations, 

subtropical climate, and water features. As such, recreational activities within the 

watershed are important to the public. Like all ecosystems, the Manatee River 

watershed has a carrying capacity for human impact before resident wildlife 


April 26, 2001 6-19 


populations and habitat values are compromised. Existing human impacts already 

have reduced habitat values of the region and the wildlife populations using those 

habitats. With projections of increases in human utilization for the area, proper 

management of human impacts must be employed to insure the viability of the 

ecosystem. 

Strategy: Provide public access to natural areas within the watershed compatible with 

ecosystem functions and wildlife requirements. 

Actions: 

1. Identify and inventory present recreation types and user demands within the 

watershed and project future needs (e.g., boating, fishing, cycling, horseback 

riding, hiking, camping, etc.). 

2. Determine existing and projected impacts of various recreational activities within 

the ecosystem. 

3. Draft management plans per each natural site appropriate for human use. As 

part of each management plan, establish public access points to these natural 

areas, directing various activities to specific areas within the site. Due to 

individual site characteristics, plans will need to address specific public 

management needs detailing resource utilization for activities such as boating, 

camping, horseback riding, and any other activity appropriate for that site. 

Interagency/government coordination should be stressed to insure uniformity in 

resource management among the differing resource areas (e.g., county parks vs 

state parks vs SWFWMD land vs federal land). 

4. Allocate sufficient staff and resources to manage public utilization of natural 

areas, inclusive of utilities (e.g., parking, potable water, restrooms, etc.), trash 

disposal, signage, and enforcement. 

5. Provide education of the value of natural ecosystems and the essential role the 

public plays in maintaining the balance of humans and the rest of the ecosystem. 

Some educational efforts will need to be site specific. 

Participants: SWFWMD, FDEP, FGFWFC, Manatee County, municipalities, NPS, 

environmental organizations 

Issue #3: Public Education 

Background: The destruction and degradation of environmental resources is due, in 

part, to the public’s, scientist’s, educator’s, and politician’s lack of understanding of the 

importance and roles that ecosystems play in their lives. Particularly since the 1960s, 

there have been significant scientific advances, better education, a more informed 

citizenry and more responsive, enlighten governments (local, state, and federal). As 

such, our natural resources have been the subject of many critically important laws, 


April 26, 2001 6-20 


egulations, and efforts to preserve, protect, restore, and manage. In spite of what 

progress has been accomplished to date, much is left to accomplish concerning the 

enlightenment of the residents and visitors to Florida. With growth projections 

indicating an upward spiral of permanent residents as well as seasonal visitors, it is 

vitally important to increase public and political awareness of our ecosystems and what 

roles humans can play in insuring the future of the region’s natural resources. 

Strategy: Coordinate efforts to properly educate the region’s residents and visitors 

concerning the importance of preserving, restoring, and managing our natural 

resources and what roles individuals can play in insuring the future of the region’s 

natural resources. 

Actions: 

1. Insure public education includes curricula concerning the environment and 

ecosystems. 

2. Insure that governmental agencies associated with environmental affairs include 

public education elements as part of their job responsibilities (e.g., public 

speaking, field trips, etc.) 

3. Encourage participation in environmental activities (e.g., marsh plantings, trash 

cleanups, etc.) and environmental organizations. 

4. Promote college and university staff and students to become involved in regional 

ecosystem affairs, providing course work specific to environmental issues, and 

conduct research important for the long term preservation, restoration, and 

management of natural resources. 

5. With recognition that many environmental decisions are made through the 

political process, encourage citizens to participate in that process. 

6. Secure responsible environmental reporting of issues in the media and attempt 

to secure media coverage of environmental efforts for the watershed (e.g., 

restoration projects, land acquisitions, volunteer efforts, etc.). 

7. Implement site specific public educational programs as noted within other issues 

detailed in this management plan (e.g., public park signage/literature, restoration 

project displays, etc.) 

Participants: SWFWMD, FDEP, FGFWFC, Manatee County (inclusive of school 

system), regional colleges/universities, various environmental organizations. 

Issue #4: Urbanization and Agriculture Encroachment 


April 26, 2001 6-21 


Background: The future of agricultural enterprises within the watershed cannot be 

determined at this time as market will dictate what crops are grown and in what 

quantities. Real estate development pressure will likely increase but agriculture will 

remain if financially successful for farmers. It is likely to evolve toward the use of better 

irrigation systems, increased use and improvement of BMPs, and more public/private 

cooperative efforts. Use of additional lands for agricultural and urban development will 

be at the expense of the natural systems. 

Manatee County experienced population growth in excess of 43% in the decade 

between the 1980 and 1990 Census. Additionally, the County estimates that its overall 

population increases by an average of 16% during “the season,” generally the period 

from Christmas to Easter. The vast majority of the residents in the County live within 

the relatively narrow corridor between the Gulf coast and I-75 which varies from about 

three to ten miles wide. Most future growth is expected to occur mainly in this corridor 

or a few miles farther east. In order to address the possibility of future urban sprawl, 

the County has established a Future Development Area Boundary (FDAB) which 

extends eastward approximately to the Lake Manatee Reservoir. Future development 

outside the FDAB will be at very low densities and there is some potential for the 

proliferation of 5 and 10-acre ranchettes. In general, Manatee County has had 

reasonable success in keeping its growth patterns fairly compact due to its policies of 

directing development by providing central water and sewer services to designated 

service areas and by discouraging development outside of those areas by not providing 

a full range of municipal services. In short, Manatee County recognizes the perils of 

urban sprawl and are striving to prevent this type of development. Most developed 

areas within the watershed have central potable water and sewer service with most 

septic tanks in very low density areas. Most wastewater is or will be reused for 

irrigation. Concerns exist about the use of reclaimed water in the Lake Manatee 

portions of the watershed due to public health questions and the possibility of 

increased nutrient loading to the Lake. 

Strategy: Properly plan and then implement growth management which will minimize 

human encroachment and impacts on important habitat areas. 

Actions: 

1. Prepare a coordinated and comprehensive land and water linkage study 

(inclusive of transportation planning) for the area and then implement 

recommendations of the study. 

2. Develop and implement developmental practices for rural areas. Explore the 

feasibility of connecting areas presently served by septic and package plant 

systems to regional treatment facilities. Transportation planning and 

implementation (as also noted in Action #1) is very important and should be 

conducted in an environmentally sensitive fashion. 

3. Coordinate land acquisition and other conservation efforts among all available 

programs (local, regional, state and federal). 


April 26, 2001 6-22 


4. Educate private landowners (inclusive of agricultural) about protection and 

management of ecosystems as well as methods to enhance/protect ecosystem 

functions of their properties. 

5. Develop coordinated permit review and information exchange among permitting 

agencies to ensure key habitat areas are considered during impact 

assessments, impact avoidance/reduction and mitigation. Land development 

designs should be a environmentally sensitive as feasible. As referenced in 

Actions #1 and 2, transportation designs should be carefully review, maximizing 

environmental safeguards for the watershed. 

Participants: SWFWMD, FDEP, FGFWFC, NRCS, Manatee County, municipal 

governments, stakeholders. 

Issue #5: Agricultural Practices and Water Discharges 

Background: Agriculture is by far the largest single land use in Manatee County and 

within the Manatee River watershed. The most common agricultural activities are 

citrus, row crop, and dairy production. The most common row crops are tomato, 

strawberry, and potato production. These agricultural activities utilize large amounts of 

water, fertilizer and pesticides to compete economically. In addition, many of the row 

crop operations utilize plastic to grow their crops. The use of plastic generates high 

volumes of runoff during storm events. Stormwater runoff combined with irrigation 

runoff convey chemical residues and sediments to tributaries, the river, and ultimately 

Tampa Bay. A review of water quality data compiled from sources including the District 

and USGS shows increasing trends for conductivity as a result of the discharge of large 

volumes of groundwater, and increasing nitrogen levels associated with agricultural 

expansion in the basin. Some runoff problems are associated with the proper 

management of animal waste products. While the use of BMPs through IFAS or the 

NRCS may resolve these problems, these programs are often voluntary and difficult to 

enforce; however, reduction of these flows can be accomplished through the use of 

proper water and chemical application rates, conversion to water conserving irrigation 

methods, reducing offsite discharges, and establishing sheet flow through adequately 

size buffer strips. As discussed elsewhere in this plan, the timing and volumes of 

freshwater to the estuary are critical for the integrity of the ecosystem and life cycles of 

organisms that use the bay. The reader is directed to the “Water Quality” section of 

this plan for additional narratives, strategies and actions. 

Strategy: Reduce agricultural discharges into the Manatee River and tributaries and 

address problems caused by use of agri-plastics. 

Actions: 

1. Identify water discharges into the river or tributaries of the river. The discharges 

should be catalogued according to severity of pollution and sediment potential. 

The severity rating should be established based on location or proximity to the 

river, size and type of agricultural operation, use of plastic, slope, soil type, and 


April 26, 2001 6-23 


uffer capability. Post-development runoff volumes should equal predevelopment 

runoff volumes as the timing and volumes of freshwater inputs to 

the river and estuary are critical for their natural functions. 

2. Identify and implement strategies to minimize untreated runoff flowing into the 

receiving waters. These strategies should include proper management of animal 

waste products. If feasible, sheetflow should be re-established through upland 

and wetland buffers. Stormwater treatment (e.g., tailwater 

recovery/sedimentation ponds) should be incorporated. 

3. Irrigation methodologies should be examined to incorporate efficient irrigation 

practices. Semi-enclosed, flood and overhead spray irrigation methods should 

be eliminated and replaced with more efficient methods. 

4. Encourage the use of alternatives to plastic that will decompose such as that 

developed by IFAS and/or proper disposal of agri-plastics, inclusive of: a) 

restrictions on burning or stockpiling of plastic within a specified distance from 

ditches, creeks, the reservoir, river, and its tributaries; and b) disposal as part of 

the permitting or AGSWM process and whole farm planning process. 

Participants: SWFWMD, FDEP, Manatee County, municipal governments, Natural 

Resource Conservation Agency, NRCS, agricultural community. 

Issue #6: Pollutant Loading 

Background: Pollutant loading primarily is being addressed under other areas of 

responsibility within this plan and the reader is directed to these sections (i.e., “Water 

Quality”). This section’s purpose is to address additional pollutant loading on the 

natural systems of the Manatee River watershed. As noted, the Manatee River 

watershed supports a variety of wildlife populations, all of which are variously sensitive 

to habitat degradation and losses. 

Pollutant loading is inherently related to the activities and land uses of watershed 

residents. 

Accelerating developmental and agricultural pressures have imposed problems for 

regional plant and animal populations. Effects that come along with development 

include but are not limited to: habitat destruction, sewage and industrial effluent 

discharge, surface and groundwater impacts, degradation of air quality, and stormwater 

runoff (urban and agricultural) that can produce acute or chronic impacts for the land, 

water and biota. 

Viable wildlife habitats are dependent on an ecologically healthy watershed. Life within 

those habitats depends on air and water in a variety of ways other than just breathing 

and drinking, respectively. For example, fishes and other species need foraging and 

spawning areas; open water habitats need to support diverse populations of 

invertebrates to feed juvenile fish as well as meet foraging requirements of amphibians, 

reptiles, avifauna, and mammals. 


April 26, 2001 6-24 


Sub-issue 6a: Agricultural chemical use and runoff (previously noted in Issue #5 

and in the “Water Quality” section of this plan) 

Sub-issue 6b: Animal waste management (previously noted in Issue #5) 

Background: Agricultural operations that involve livestock generate animal wastes. 

The wastes are concentrated in some operations (e.g., dairies, feedlots) and more 

diffuse in others (e.g., open grazing). Improperly run operations can result in 

stormwater discharges high in nutrients, bacteria, viruses, and (potentially) other 

substances that can degrade water quality of downstream areas or, due to seepage, 

contaminate groundwater sources. 

Sub-issue 6c: Sewage treatment and discharges, inclusive of sludge disposal 

Background: Wastewater treatment plants (WWTP) function to remove organic and 

inorganic solids from sewage; properly operating facilities (particularly advanced 

wastewater treatment plants [AWT]) produce effluents that have relatively small 

environmental impacts. While most of the urban areas of Manatee County are 

connected to the sewer system, most rural areas use septic systems to treat 

wastewater. The wastewater treatment plant of Bradenton is located within the 

Manatee River watershed. The method of wastewater treatment at this plant is AWT. 

This process is a combination of one or more biological, chemical or physical 

processes that remove pollutants like phosphates, nitrates, ammonia and organic 

compounds. Furthermore, this treatment method reduces the amount of suspended 

solids and the biological oxygen demand (BOD) to 1% or less of the original 

concentration found in raw sewage. Once the wastewater has been treated, effluent 

and sludge disposal must be environmentally friendly. Water treatment reduces the 

concentration of organic and inorganic compounds to levels which can be safely 

assimilated by organisms in the natural waterways. Effluents are then discharged into 

the lower Manatee River, where an established buffer zone exists. This activity is 

regulated by the FDEP under Chapter xxx F.A.C. 

The disposal of domestic sludge is primarily accomplished by landspreading. Until 

recently, this activity also was regulated by the FDEP, but in 1997 the Board of County 

Commissioners of Manatee County adopted Chapter 62-640 F.A.C. under County 

Ordinance No. 97-26. This ordinance details minimum setbacks according to the 

surface water classification (i.e., Class 1 or OFW waters require setbacks of 3000’ and 

all other classifications offer protective buffers of 200’). Landspreading is performed 

primarily by the agricultural community to enrich their pastures. That use also requires 

an approved Agricultural Use Plan under this ordinance. 

As noted, septic tanks are located mainly in the rural areas of the Manatee River 

watershed. Septic systems are less efficient in cleansing sewage as compared to 

WWTPs particularly if the home system is poorly maintained. If soils are highly porous, 

poorly treated septage can reach groundwater, riverine, or estuarine systems 

potentially polluting these systems with pathogens, heavy metals and/or nutrients. 


April 26, 2001 6-25 


Sub-issue 6d: Air Quality and Atmospheric Deposition 

Background: Healthy, viable ecosystems require clean air. Poor air quality can 

seriously compromise all other aspects of an ecosystem, both terrestrial as well as 

aquatic. As such, clean air within the Manatee River watershed is paramount for the 

long term success of the ecosystem and the public found there. For example, the 

Tampa Bay National Estuary Program has documented the role of atmospheric 

deposition of pollutants in reducing water quality of Tampa Bay (TBNEP 1996). 

Research around the world has documented that poor air quality can contribute to other 

problems such as acid rain, destruction of the ozone layer, and a myriad of organismal 

health problems such as respiratory ailments and cancer. Some effects on the 

ecosystem are indirect, such as when acid rains mobilize heavy metals (e.g., aluminum, 

manganese, copper, lead, zinc, mercury, cadmium) that can then leach into aquatic 

systems. 

Air emissions and air quality are the responsibility of FDEP. Chapter 62-204 F.A.C. 

establishes the maximum allowable levels of pollutants in the ambient air while Chapter 

62-296 F.A.C. establishes emission limiting standards and compliance requirements for 

stationary sources of air pollution. 

Currently, Manatee County has three air monitoring sites recording ozone, sulphur 

dioxide, particulate matter (PM), PM-10 (particles

cause erosion of stream banks, transport sediment loads and contribute pollutants to 

the river and estuary. Contaminants typically associated with stormwater include 

nutrients, pathogens, organic compounds and metals. Differing land uses provide 

differing qualities of runoff. Land uses that contaminate stormwater can eventually 

cause contamination of groundwater in aquifer recharge areas. This stormwater runoff 

will flush contaminants into the watershed and in some cases lethal doses of pollutants 

may reach the waterways. Fish kills may happen especially during the “first flushes”, 

due to impacts of organic matter and nutrients. Decaying organics can reduce 

dissolved oxygen levels in the water column thus causing fish asphyxiation. Benthic 

communities also can suffer high mortalities during periods of low oxygen. At the same 

time, algae blooms can occur due to the nutrient loading. Another factor to consider is 

the bioaccumulation of toxins that may occur within the local flora and fauna. In 

summary, continuous inputs of these contaminants may threaten the sustained 

productivity of the Manatee River watershed ecosystem. 

Strategy (all sub-issues above): Improve habitat, water, and air quality through 

reductions and better management of environmental pollutants. 

Actions: 

1. Identify existing and proposed (future) land uses and create a growth 

management plan to address stormwater, sewage, and air quality issues. 

Implement the plan. 

2. Establish vegetative buffers and riparian corridors. 

3. Identify areas needing stormwater treatment and implement programs to address 

stormwater issues. 

4. Identify sources of air pollution and implement programs to reduce pollutants 

within the emissions. 

5. Establish budgets and schedules for stormwater, sewage and air quality 

programs. 

6. Apply to federal and state granting programs to assist in the implementation of 

these programs. 

Participants: EPA, NRCS, SWFWMD, FDEP, Manatee County, City of Bradenton, City 

of Palmetto. 

Issue #7: Polluted Sites and Hazardous Wastes 

Sub-issue 7a: Superfund and Known Polluted Sites 


April 26, 2001 6-27 


Background: Superfund sites are those locations whose pollutant levels are a threat 

to public health, safety and welfare. Among the common hazardous sites are: 

abandoned warehouses, manufacturing facilities, processing plants and landfills. 

In 1980, Congress established the Superfund Program to clean up polluted sites. The 

U.S. Environmental Protection Agency (EPA) administers this program. EPA locates, 

investigates and cleans up hazardous waste sites throughout the United States. The 

regulations applied to these sites are under the Code of Federal Regulation (CFR) Title 

40. Manatee River watershed has four superfund sites: 

Superfund Name 

Location 

Lena Road Landfill 

Lena Road 

Bradenton Gasification Plant 

Intersection of 6 th Ave. and 3 rd St. 

Pier Property Drum Southeast of I-75 and S.R. 64 

For the most part, pollutants at each site are believed to be contained at each location. 

These areas are all located some distance away from any waterways within the 

Manatee River watershed; nevertheless, leaching of pollutants is a concern for areas 

down gradient or the aquifer under the sites. 

The other kind of pollutant found within the Manatee River watershed is petroleum. 

The Department of Environmental Protection manages the Tank Program under 

Chapters 62-761 (underground tanks) and 62-762 (above-ground tanks) F.A.C. Among 

others, this program addresses petroleum contained in tanks used in gas stations, fuel 

for industries, and diesel tanks for irrigation use in agricultural practices. These 

facilities are annually inspected for compliance and checked for leaks by the 

Environmental Management Department (EMD) of Manatee County. A Petroleum 

Contamination annual report is available for Manatee County. This report describes 

the facility general information, the contaminated media (soil, surface water, 

groundwater, monitoring wells and number of drinking wells close by) and any 

prescribed cleanup process if a leak occurred during the year. These facilities are 

mainly located west of I-75 (i.e., gas stations and auto services) and to a lesser degree 

east of I-75 where above ground tanks are used for ranches, citrus groves and crop 

areas. The main concern still focuses on older systems, and code requires all systems 

to upgrade by the year 2009. 

Sub-issue 7b: Hazardous Waste Generation and Disposal 

Background: The Resource Conservation and Recovery Act gave authority to EPA to 

regulate hazardous wastes (40 CFR Sections 260-271). DEP adopted these rules by 

creating the Hazardous Waste Rule under Chapter 62-730 F.A.C. Hazardous waste 

generation falls under three categories: 

1) Conditionally Exempt - 1000 kg/month (over 5 drums) 


April 26, 2001 6-28 


This program records each facility by the type of waste, the storage handling and the 

disposal method. Hazardous wastes are found mainly in commercial and industrial 

activities (e.g., pesticides, wastewaters with heavy metals, antifreeze, inks, Freon, dry 

cleaning chemicals, etc.). Since regulated, commercial and industrial sites may not 

cause as many problems for the watershed as hazardous wastes generated by 

domestic households. 

Common hazardous household products are plentiful and widespread (e.g., batteries, 

cleaners, paints, pesticides, herbicides, glues, etc.). These products are typically 

disposed of by pouring on the ground, down drains or mixed with domestic garbage. 

Hazardous household products are often stored for long periods of time (e.g., 5-10+ 

years). Containers of such substances may deteriorate in time and leak, and during 

storm or flood events they can enter surface waters or percolate into the water table. 

Strategy (for sub-issues above): 

Actions: 

1) Identify existing problems of polluted sites and how to address those 

problems; 

2) develop a plan to minimize or eliminate hazardous waste in the Manatee 

River watershed. 

1. Identify and register with FDEP all businesses categorized as small or large 

quantity generators. 

2. Coordinate with EPA for cleanup of known Superfund and other polluted sites. 

3. Require local businesses to assess wastes they produce and handle them with 

greater care. 

4. Provide technical assistance and educational literature to small businesses. 

5. Encourage businesses to use alternative, more environmentally friendly 

products, and, as feasible, reduce waste and recycle. 

6. Develop a local Hazardous Waste Management Plan. 

7. Educate consumers on the purchase, use, and storage of products. 

8. Establish collection events and regular collection sites (e.g., “Amnesty Days” 

program). 

Participants: EPA, FDEP, Manatee County, City of Bradenton and the City of 

Palmetto, public education programs 


April 26, 2001 6-29 



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April 26, 2001 6-31

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