Little Manatee River - Southwest Florida Water Management District

Little Manatee River
Comprehensive Watershed
Management Plan
Little Manatee River @ I-75
Agriculture
State Park
Fish Farm
Phosphate Mining
2002

LITTLE MANATEE RIVER
COMPREHENSIVE WATERSHED
MANAGEMENT PLAN
June, 2002
Prepared by:
Southwest Florida Water Management District
2379 Broad Street
Brooksville, Florida 34604
The District does not discriminate upon the basis of any individual’s disability status. Anyone requiring
reasonable accommodation under the ADA should contact the Planning
Department at 352-796-7211 or 1-800-423-1476 (Florida only), extension 4400;
TDD ONLY 1-800-231-6103 (Florida only); FAX 352-754-6749/SUNCOM 663-6749.

TABLE OF CONTENTS
ACRONYMS
EXECUTIVE SUMMARY
ii
v
CHAPTER I. INTRODUCTION 1.1
CHAPTER II. WATERSHED DESCRIPTION 2.1
CHAPTER III. WATER SUPPLY 3.1
CHAPTER IV. FLOOD PROTECTION 4.1
CHAPTER V. WATER QUALITY 5.1
CHAPTER VI. NATURAL SYSTEMS 6.1
REFERENCES 7.1
FIGURES
Figure 1-1, Southwest Florida Water Management District CWM Watersheds 1.2
Figure 1-2, Sustainability Through Science 1.4
Figure 1-3, Fiscal Year 2000 Estimated Water Resources Funding by Activity and
Funding Sources 1.5
Figure 1-4, Little Manatee River CWM Estimated Water Resources Funding by
Activity for Fiscal Year 2000 1.6
Figure 3-1, Special Groundwater Use Areas Overlapping Little Manatee River
CWM Area 3.12
Figure 5-1, Groundwater Quality Monitoring Wells 5.2
TABLES
Table 2.1, 1995 Land Use/Land Cover for the Little Manatee River Watershed 2.4
Table 3.1, 1998 Water Withdrawals in the Little Manatee River Watershed 3.2
Table 4.1, 1995 Urban Land Use (Existing) within FEMA 100 Year Flood Zone 4.10
Table 5.1, Water Quality in Selected Surficial Aquifer Wells 5.3
Table 5.2, Water Quality in Selected Intermediate Aquifer Wells 5.5
Table 5.3, Water Quality in Selected Upper Florida Aquifer Wells 5.7
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ACRONYMS
ABM
AGWQMP
AMP
AOR
ASR
BEBR
BMP
BOD
CAPMAT
CBAP
CARL
CCMP
CFR
CWM
D-BUG
DCA
DIN
DOAH
DO
DWMP
EAC
ELAPP
ELMAC
EPCHC
ERP
ETB
F.A.C.
FAVA
FDEP
FDOT
FEMA
FFWCC
FIRM
FNAI
FP&L
F.S.
GIS
GPD
HR
ICP
IHN
IWRM
LOS
Agency on Bay Management
Aquifer Groundwater Quality Monitoring Program
Ambient Monitoring Program
Area of Responsibility
Aquifer Storage and Recovery
Bureau of Economic and Business Research
Best Management Practice
Biochemical Oxygen Demand
Cockroach Bay Management Advisory Team
Cockroach Bay Aquatic Preserve
Conservation and Recreation Lands
Comprehensive Conservation and Management Plan
Code of Federal Regulation
Comprehensive Watershed Management
Database Users Group
Department of Community Affairs
Dissolved Inorganic Nitrogen
Division of Administrative Hearings
Dissolved Oxygen
District Water Management Plan
Environmental Action Committee
Environmental Lands Acquisition and Protection Program
Environmental Lands Management and Acquisition Committee
Environmental Protection Commission of Hillsborough County
Environmental Resource Permit
Eastern Tampa Bay
Florida Administrative Code
Florida Aquifer Vulnerability Assessment
Florida Department of Environmental Protection or Department
Florida Department of Transportation
Federal Emergency Management Agency
Florida Fish and Wildlife Conservation Commission
Flood Insurance Rate Map
Florida Natural Areas Inventory
Florida Power & Light
Florida Statutes
Geographic Information System
Gallons Per Day
Highlands Ridge
Integrated Conservation Plan
Integrated Habitat Network
Integrated Water Resource Monitoring
Level of Service
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LaMP Lake Monitoring Program
MFL Minimum Flows and Levels
mgd million gallons per day
mg/L milligrams per liter
MIA Most Impacted Area
MSSW Management and Storage of Surface Waters
MSW Municipal Solid Waste
NEP National Estuary Program
NGVD National Geodetic Vertical Datum
NOAA National Oceanic and Atmospheric Administration
NOX Nitrogen Oxides
NPDES National Pollutant Discharge Elimination System
NRCS Natural Resources Conservation Service
NWSI New Water Sources Initiative
OFW Outstanding Florida Water
PAH Polycyclic Aromatic Hydrocarbons
PLRG Pollutant Load Reduction Goal
PM
Particulate Matter
ppt
parts per thousand
PR/MRWSA Peace River/Manasota Regional Water Supply Authority
P2000 Preservation 2000
RAMP Regional Ambient Monitoring Program
ROMP Regional Observation Monitoring Program
RWSP Regional Water Supply Plan
SOR Save Our Rivers
STORET Storage and Retrieval
SWFWMD Southwest Florida Water Management District or District
SWIM Surface Water Improvement and Management
SWUCA Southern Water Use Caution Area
TBEP Tampa Bay Estuary Program
TDS Total Dissolved Solids
TMDL Total Maximum Daily Load
TNC The Nature Conservancy
TPL Trust for Public Lands
TSI
Trophic State Index
TSS Total Suspended Solids
g/L micrograms per liter
UF
University of Florida
USEPA US Environmental Protection Agency
USFWS US Fish and Wildlife Service
USGS US Geological Survey
WCRWSA West Coast Regional Water Supply Authority
WHPA Wellhead Protection Areas
WQI Water Quality Index
WQMP Water Quality Monitoring Program
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WQMN
WRAP
WRCA
WUCA
WWTP
Water Quality Monitoring Network
Water Resource Assessment Project
Water Resource Caution Area
Water Use Caution Area
Wastewater Treatment Plant
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EXECUTIVE SUMMARY
The Southwest Florida Water Management District (District) developed the Comprehensive
Watershed Management (CWM) Program for water resource assessment and planning on a
regional basis. The CWM Program was designed to allow for evaluation of the status of water
resources, with special attention paid to the District’s primary Areas of Responsibility (AORs): 1)
water supply, 2) flood protection, 3) water quality and 4) natural systems. This document
represents the first plan for the Little Manatee River CWM effort.
The Little Manatee River CWM area, covering approximately 175,928 acres, extends over
Hillsborough and Manatee counties. The area is bordered by the Alafia River watershed to the
north, Peace River watershed to the east, Manatee River watershed to the south and Tampa Bay to
the west. Agriculture is the major land use activity in the watershed. Areas in the watershed’s
western extent also include several small urban communities (e.g., Sun City, Sun City Center,
Parrish, Ruskin, Palmetto) and an industrial area associated with Port Manatee. The eastern extent
contains several areas that have been mined, experiencing mining or planned for the activity in the
future.
The Little Manatee River plan is a comprehensive resource management document. The general
approach taken to develop this plan was to evaluate completed and ongoing resource assessments
and existing and potential future activities within the area, and then identify resource issues and
strategies and actions for addressing them. The plan uses a collaborative approach to resolving
issues. That is, in most cases, more than one entity is usually identified as having a role or
responsibility for addressing a particular problem.
Summarized below are the Team’s major priorities by AOR:
For Water Supply, there is a need to: 1) refine issues to be addressed, including development and
implementation of a management program for the Southern Water Use Caution Area which
provides natural resource protection while maximizing water supply; identify regulatory and nonregulatory
alternatives for cooperative management; evaluate and modify minimum aquifer levels;
form a work group of affected parties, 2) improve coordination between land and water planners,
3) re-evaluate agriculture’s contribution to stream flow, 4) review regulations for phosphate mine
reclamation to determine impact on stream flow characteristics and 5) establish minimum flows
for river in the 2006-2015 time frame.
For Flood Protection, there is a need to: 1) standardized hydrologic/hydraulic and flood protection
data collection and management, 2) develop a GIS database of current floodplain information, 3)
develop analysis protocol that contributes to the minimization of impacts beyond peak flows, 4)
develop detailed modeling protocol for watershed analysis, 5) develop guidelines that consider the
dual use of flood control ponds, statistical comparisons between design and actual constructed
imperviousness, 6) develop impact-based solutions for watershed and 7) evaluate and enhance
the surface water monitoring network.
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For Water Quality, there is a need to: 1) re-examine water quality trends and dissolved oxygen
concentrations and identify factors contributing to the conditions, 2) pursue the implementation of
best management practices to reduce non-point source nutrient loading from agricultural lands, 3)
study areas with high septic tank densities to determine if pollution problems exist, 4) perform
water quality assessments in areas used for sludge disposal, 5) continue land acquisition activity,
6) improve efficiency and coordination in water quality data collection, 7) determine regions of the
watershed where significant quantities of irrigation water enter the river and 8) coordination
among agencies and citizenry on water quality issues.
For Natural Systems, there is a need to: 1)protect remaining natural systems through land
acquisition and other land conservation methods, 2) conduct habitat enhancement, restoration
and creation projects to restore lost and degraded habitats, 3) provide public access to natural
areas compatible with ecosystem functions and wildlife requirements, 4) coordinate efforts of
governments and environmental agencies and groups to educate the region’s citizenry, 5) manage
encroachment of urban and agricultural development, 6) eliminate or reduce mining impacts to
natural systems and 7) manage pollutant loading.
Background information that led to the prioritization of these needs is found in chapters relating to
the District’s AORs - water supply, flood protection, water quality, and natural systems. The
desire of the individuals who helped to develop the Little Manatee River Comprehensive
Watershed Management Plan is that this document would be modified and updated regularly, as
required. It is hoped that most of the projects outlined within this text will be funded and
completed through the combined efforts of the appropriate federal, state, regional and local
governments.
Many thanks are due to the members of the Little Manatee River CWM Team for their long hours
spent on this project.
Name
Rand Baldwin
Greg Blanchard
Daniel Blood
Rob Brown
Malcolm Castor
Shawn College
Harry Downing
Sid Flannery
Brian Grady
Dawn Hart
Brandt Henningsen
Lisa Henningsen
Scott Hickerson
Janet Hoffman
Mike Kelley
Ed Kouadio
Colleen Kruk
Gordon Leslie
Will Miller
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Affiliation
Southwest Florida Water Management District
Manatee County
Hillsborough County
Manatee County
Southwest Florida Water Management District
Hillsborough County City-County Plan. Comm.
Southwest Florida Water Management District
Southwest Florida Water Management District
Hillsborough County
Environ. Protection Comm. of Hillsborough Cty
Southwest Florida Water Management District
Southwest Florida Water Management District
Southwest Florida Water Management District
Manatee County
Southwest Florida Water Management District
Southwest Florida Water Management District
Southwest Florida Water Management District
Environ. Protection Comm. of Hillsborough Cty
Southwest Florida Water Management District
vi

Little Manatee River CWM Team list continued:
Name
Steve Minnis
Trisha Neasman
John Rickerson
Nancy Rubin
John Walkinshaw
Toni Edwards
Andrea Grainger
Deby Scerno
Affiliation
Southwest Florida Water Management District
Southwest Florida Water Management District
Southwest Florida Water Management District
Hillsborough County
Southwest Florida Water Management District
Department of Environmental Protection
Department of Environmental Protection
Department of Environmental Protection
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CHAPTER I. INTRODUCTION
1.1 Purpose of the Comprehensive Watershed Management Plan
The purpose of the Comprehensive Watershed Management (CWM) plan is to coordinate various
water resource related projects within the Little Manatee River Watershed. Potential projects
include potable water supply assessment and development, hydrologic restoration in impacted
areas, flood protection/storm water management, land acquisition and habitat restoration, water
quality monitoring and assessment, floodplain mapping, potable water conservation and many
others. Existing data and analysis and input from local governments and other stakeholders form
the basis for identifying problem areas and priorities within the watershed, and for developing
action and funding strategies to address identified problems and prevent future ones.
The watershed management plan will be coordinated with the Alafia River and Manasota Basin
Boards’ five-year plans. The purpose of this coordination is to further long-range planning within
the Little Manatee River watershed, to improve internal communications among local
governments, watershed stakeholders and the Boards and staff of the Southwest Florida Water
Management District (SWFWMD or District). This plan is intended to be an action plan with
ongoing implementation of identified projects. The Plan is also intended to encourage local
governments and other appropriate entities to participate in the District’s Cooperative Funding
Program whereby the District’s Basin boards provide matching funds for projects consistent with
the District’s water resource management goals.
1.2 Comprehensive Watershed Management
The District's CWM initiative has been established to improve the management of water and
related natural resources within the District. This initiative integrates a wide variety of resource
activities to employ a watershed approach to resource management. In FY 1994, the District
Governing Board made CWM a strategic initiative, and consequently directed staff and funding
resources to the effort. Additionally, the various Basin boards have made watershed assessments
a priority for future cooperative funding proposals and projects.
The District is applying this CWM approach to 11 watersheds to protect and/or restore their water
resource assets. These 11 watersheds reside in the sixteen counties that make up the District.
Staff from a variety of disciplines and departments make up “watershed teams” that have been
assigned to the 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;
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Figure 1-1. Southwest Florida Water Management District, CWM Watersheds.
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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 preventive or remedial management actions to address these resource
management issues;
4. Identify funding sources and partnerships to support action plan projects; and,
5. Implement and monitor the effectiveness of selected actions and the overall process and
recommend potential revisions.
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 scope, yet simple in intent and
design. They analyze the wealth of information available in each area, identify issues and
recommend 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 (DWMP) through incorporation by reference. These plans reflect
a “snapshot-in-time” of the watershed and will be periodically updated.
Coordination
A significant element of the CWM initiative is the active involvement of the local government(s)
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 track. Scientific knowledge serves as the
backbone to this process and allows us to achieve the desired watershed condition (Figure1-2).
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 preventive or remedial strategies and coordinated implementation. Agencies
which are, or will be, requested to participate in the CWM process include the Florida Department
of Environmental Protection (FDEP), 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.
In addition, the District’s Alafia River Basin Board and Hillsborough County jointly funded a
land/water linkage project to enhance outreach, communication and education within the Little
Manatee River watershed. This project involved several months of facilitated work sessions with
local stakeholders on issues and recommended management strategies for the Little Manatee
River watershed. A report entitled Little Manatee River Watershed Plan Land/Water Linkage
Project-Staff Report, identifying specific strategies, action plans, projects and priorities for land and
water management in the watershed, was completed as part of the effort.
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Figure 1-2. Sustainability Through Science.
The land/water linkage report is a free-standing document, but is considered an important
component of the watershed planning process for the Little Manatee River area.
Recommendations contained in the report will be heavily relied on for project identification and
development.
The CWM initiative helps to ensure that comprehensive, coordinated analysis and decisionmaking
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.
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
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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 $12 million are
designated for Little Manatee River watershed projects (Figure 1-4). This does not include the any
other resource management activities undertaken by local governments, FDEP and others.
Implementation
Each watershed management team has suggested specific and realistic actions and tasks.
Recommendations considered District responsibilities will be prioritized by a District senior
management team (Steering Committee). The Steering 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 annually.
As a result of the District’s actions, it is anticipated that local governments and others will
prioritize and implement resource management strategies within their areas of responsibility. A
formal partnership or Memorandum of Understanding between the District and participating
parties may be considered for coordinated implementation of these 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 plans
for the Basin Boards and in the District’s accountability and performance reporting.
Figure 1-3. Fiscal Year 2000 Estimated Water Resources Funding by Activity and Funding Source.
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Figure 1-4. Little Manatee River CWM Estimated Water Resources Funding by Activity for Fiscal Year
2000.
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 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. GIS also provides a means of integrating
disparate data such as census information and Federal Emergency Management Agency (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 enhance coordinated action.
This GIS-based analysis and planning has, to date, been applied only to a limited degree in
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selected watersheds. It is a major objective of the District that the use of 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 Little
Manatee River Comprehensive Watershed Management Plan will reflect progress made in the GISbased
partnership approach.
1.3 District Directives
The state of Florida has a unique relationship with water. As a peninsula, the State is nearly
surrounded by the sea and has 11,000 miles of coastline. Moreover, the quality of life in Florida is
inseparably linked with its water resources. The majority of today's population and the trend of
present growth patterns reflect coastal settlement, where freshwater is least abundant and natural
systems such as estuaries and wetlands are most vulnerable. As a result, water management in
the 2000s involves a challenge of sometimes conflicting priorities to provide adequate water
supplies for human needs, appropriate flood protection, and sound management of water quality
and natural systems. It is the State's five water management districts, and FDEP, that must meet
this challenge and address the unique water resource issues of the various regions of our State.
Federal, state, regional and local agencies responsible for land planning and development also
have a significant role to play in protecting water-related resources. The DWMP provides a
comprehensive guide to the District in carrying out all of its water resource management
responsibilities, including water supply and protection of natural systems.
The genesis of the DWMP is Chapter 373 of the Florida Statutes (F.S.). Specific intent for this
planning is further delineated in State Water Policy (Chapter 62-40, Florida Administrative Code
(F.A.C.)). The DWMP serves a number of purposes:
To provide a road map for the SWFWMD in managing and protecting water and related
natural resources. It is the stated desire of the Governing Board to accomplish long-range
planning in the best interest of the resource;
To enhance consistency and accountability among all five water management districts and
FDEP through communication and coordination on common issues and responsibilities;
To further the State Comprehensive Plan;
To foster coordination among the many levels of government, and better public
understanding of water management policies and decisions; and
To provide a compendium of water resource information to assure sound management,
including but not limited to a 20-year water supply needs and sources assessment, and
identification and response to existing and potential areas where water resource problems
have or will become critical.
The DWMP is a component of the Florida Water Plan. All five districts and FDEP have worked
closely together to achieve consistency among their plans. These plans reflect consensus on our
four resource-based areas of responsibility (water supply, flood protection, water quality
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management and natural systems management) and the planning steps to be applied to each. In
this way, the Florida Water Plan can accurately reflect regional differences, while communicating
the basic policy direction for statewide water management.
1.3.1 Mission Statement
The CWM program, as with all District activities, must be consistent with the District's mission.
The Governing Board of the Southwest Florida Water Management District has adopted a formal
Mission Statement, as follows:
The mission of the Southwest Florida Water Management District is to manage water and
related natural resources to ensure their continued availability while maximizing
environmental, economic and recreational benefits. Central to the mission is maintaining
the balance between the water needs of current and future users while protecting and
maintaining water and related natural resources which provide the District with its existing
and future water supply.
The Governing Board of the District assumes its responsibilities as authorized in Chapter 373 and
other chapters of the Florida Statutes by directing a wide-range of programs, initiatives, and
actions. These include, but are not limited to, flood protection, water use, well construction and
environmental resource permitting, water conservation, education, land acquisition, water
resource and supply development and supportive data collection and analysis efforts. (SWFWMD,
2000).
1.3.2 Primary Areas of Responsibility and Goal Statements
The District's mission is divided into four primary Areas of Responsibility. Goals have been
developed to establish the long-term direction of programs and activities that address water
resource issues. The missions within these AORs and their respective goals are as follows:
Water Quality:
Flood Protection:
Natural Systems:
Water Supply:
To protect water quality by preventing further degradation of the water
resource and enhancing water quality where appropriate.
To minimize the potential for damage from floods by protecting and
restoring the natural water storage and conveyance functions of floodprone
areas. The District shall give preference wherever possible to
nonstructural surface water management methods.
To protect, preserve and restore natural Florida ecosystems and to establish
minimum water levels and flows necessary to maintain these natural
systems.
To ensure an adequate supply of the water resource for all reasonable and
beneficial uses, now and in the future, while protecting and maintaining the
water and related resources of the District (SWFWMD, 1995).
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These regional water management goals build a bridge between the divergent functions of the
District, local, other regional, state and federal agencies. This bridge creates common ground for
consistent, coordinated action in the best interest of Florida citizens. The predominant theme of
this watershed management plan is the effective integration of land and water planning to achieve
sound resource management and protection.
The AORs have been agreed upon by all five water management districts and FDEP as
representative of our collective water management agenda. This coordinated decision was a
development step of the comprehensive, 20-year DWMP. The District’s DWMP identified the
issues that led to the creation of the Comprehensive Watershed Management initiative.
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CHAPTER II. WATERSHED DESCRIPTION
2.1 Location
The Little Manatee River originates in a swampy area east of Fort Lonesome in southeastern
Hillsborough County and flows generally westward for about 40 miles toward its discharge point
into Tampa Bay near Ruskin. The river drains approximately 222 square miles of land. For the
period 1940-1999, the river’s yearly mean discharge was 171 cfs at the U.S. 301 bridge (United
States Geological Survey (USGS), 2000).
The Little Manatee River watershed extends over the southern part of Hillsborough County and
the northern portion of Manatee County (see Atlas map 1). The watershed is bordered by the
Alafia River watershed to the north, the Manatee River watershed to the south and to the east by
the Peace River watershed. The watershed incorporates the City of Palmetto and communities of
Parrish, Ruskin, Sun City, Wimauma and Terra Ceia. Other features of interest include Lake
Wimauma, Lake Parrish, the Little Manatee River State Recreation Area and the Cockroach Bay
Aquatic Preserve.
2.2 Climate
West-central Florida has a humid subtropical climate. The mean normal yearly temperature for
Hillsborough County is 72.2 o F, generally ranging from a normal maximum temperature of 91 o F in
July and August, to a normal minimum temperature of 49 o F in January. Evapotranspiration for the
area encompassing the Little Manatee River watershed is approximately 39 inches per year
(SWFWMD, 1994). Greatest ET rates occur in May and June, and nearly 60 percent of the total
yearly ET occurs during the period between May and October.
There are nine District rainfall stations in the Little Manatee River watershed: two in the east, three
in the center and four in the west. The annual average precipitation for the Little Manatee River
watershed rainfall stations was 33.94 inches for the year 2000 (SWFWMD Water Management
Database). For the period 1915-2000, the annual average rainfall for the watershed is 52.72
inches. In a typical year, approximately 60 percent of the annual precipitation comes from
convective thunderstorms during the four-month period between June through September.
Periods of extremely heavy precipitation associated with the passage of tropical low pressure
systems may occur during summer and early fall.
2.3 Physiography
The Little Manatee River watershed lies within three physiographic provinces; the Gulf Coastal
Lowlands, DeSoto Plain and the Polk Upland (White, 1970). The lower portion of the watershed
flows over the Gulf Coastal Lowlands province and DeSoto Plain, relatively flat plains extending
eastward with a gentle slope upward to the border with the Polk Upland physiographic province.
The western edge of the Polk Upland is defined by the presence of the first of several
paleoshoreline scarps associated with the Pleistocene ice-age sea level fluctuations. This
physiographic feature is known as the Pamlico Scarp or shoreline (Healy, 1975). Elevations in the
Gulf Coast lowlands and DeSoto Plain range from sea level to 50 feet.
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The remainder of the Little Manatee River watershed is situated in the Polk Upland Province.
Elevations in the extensive Polk Upland range up to between 100 and 130 feet. The watershed’s
elevations, however, range between 25 and 75 feet. Eastward of the Pamlico Scarp the river's
banks attain a narrower, steeper profile and some spots are bluff-like with 20-25 feet of relief from
the river's water level. In the vicinity of Wimauma, the physiography adjacent to the river is
composed of low sand hills which in some cases attain 75 feet in elevation. The Talbot and
Penholoway paleoshorelines pass through this area in a north-south orientation, with identifying
surface features having elevations of 25 to 42 and 42 to 75 feet, respectively.
In the Polk Upland province, near the town of Fort Lonesome, the river travels over the clay-rich
Bone Valley Member of the Peace River formation. This is the lithologic unit planned for extensive
mining for phosphate minerals in the eastern part of the Little Manatee watershed. The river's
banks in this region become less steep with many low relief floodplain or wetland areas
surrounding the river. Much of this area will have its physiography and associated surface water
drainage systems modified by future mining activity. Altered physiographic features in this region
will include many water-filled, former mine pits and large, diked clay-settling areas of various
rectilinear configurations as in the Alafia River watershed.
Primary soil groups in the Little Manatee River watershed include the Myakka-Urban land-St.
Augustine and Estero-Wulfer-Kesson groups in the coastal areas. These associations are nearly
level, poorly drained black soils commonly found in swamps, tidal marshes and river floodplains.
Inland from these areas, the prevalent soil types are the EauGallie-Floridana, Myakka-Basinger-
Holopaw, Malabar-Wabasso-Bassinger, Myakka Immokalee-Pomello, Myakka Waveland Classic
and Waveland-Pomello-Myakka associations. These groups include nearly level and poorly to
moderately drained soils characteristic of flatwood areas (Soil Conservation Service, 1983 &
1989).
2.4 Hydrogeology
The Little Manatee watershed is underlain by water-bearing limestones and dolomites of Eocene
to Miocene age, covered by a 200-300 foot layer of unconsolidated sands and sandy clays of
Pliocene, Pleistocene and Recent origin. The watershed lies within the southern groundwater
basin, and contains three distinct aquifer systems: the surficial, intermediate and Floridan. The
surficial aquifer is unconfined and is composed of variable amounts of clean quartz to clayey sand.
At the base of the surficial aquifer, there may be phosphate grains and clays present that have
been reworked from the underlying phosphate-bearing Bone Valley Member (Upchurch,1985).
The underlying intermediate aquifer is made up of the permeable lithologies present in the
Hawthorne Group including the lowermost limestone unit (Tampa Member). In the Little
Manatee River watershed, the intermediate aquifer serves as a locally important potable water
source for domestic wells.
The upper Floridan aquifer interval is the primary artesian aquifer throughout Florida and much of
the southeastern United States. It includes all the limestone and dolomite layers of Eocene to
Miocene age that lie below the upper confining layer that separates it from the overlying
intermediate aquifer. The average thickness of the Floridan aquifer system is approximately 1100
feet in the Little Manatee River watershed area (Wolansky and Thompson, 1987). The Floridan
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aquifer is the potable water source for most of the watershed. In the coastal areas, this aquifer
contains high total dissolved solids making it less desirable for potable water and for some
agricultural purposes.
2.5 Land Use, Growth and Economy
The Little Manatee river watershed is a relatively undeveloped watershed in comparison to others
draining to Tampa Bay. Table 2.1 and Atlas maps 3 and 4 provide the distribution of generalized
land uses and land cover for the watershed in 1995. As indicated by these sources, the majority
(49.7 percent) of the land within the watershed is considered agricultural. This land use pattern
predominates particularly in the central and eastern portions of the watershed. Agricultural
activity commonly associated with the area includes citrus, dairy, row crops and aquaculture.
The eastern half of the watershed is part of the phosphate district. In this area, the phosphate
industry has large holdings either being mined or slated for the activity in the near future. Future
mining areas are often placed in an agricultural use such as pasture lands until the activity occurs.
The acreage for this activity is included in the urban and built category.
In the watershed’s western quarter, near the coast, urban development is prevalent. This
development pattern appears as a band running north-south. The band encompasses the
communities of Ruskin, Sun City, Sun City Center and Palmetto. It also includes the Port Manatee
area, a port/industrial facility on Manatee County’s northern coastline. In terms of port activity,
the facility is the fifth largest in the state of Florida (Bureau of Economic and Business Research
(BEBR), 2001).
Throughout the remainder of the watershed, large expanses of undeveloped swamps and uplands
exist. These lands are the most prevalent along the riverine corridors, including the North and
South Forks up to the headwater areas. In 1995, natural lands (i.e., upland forest and wetlands)
made up 45,986 acres or 26 percent of the total watershed acreage.
Between 1990 and 2000, the population of Hillsborough County increased by nearly 20 percent
from 834,054 in 1990 to 998,948 in 2000. The population in Manatee County over the same
period increased from 211,707 to 264,002, or by 25 percent (U.S. Census, 2001). These counties
are expected to experience more moderate growth for the period 1999 to 2010. Projected growth
rates are 16 percent for Hillsborough County and 19 percent for Manatee (BEBR, 2001).
Services and retail trade have traditionally dominated the economy of the Tampa Bay area, which
includes Hillsborough Pasco, Pinellas and Manatee counties. U.S. Labor Department statistics
indicate that in 1980, approximately 52 percent of the workforce in the region was employed
within services and retail trade. This percentage increased to 57 percent by 1996, with the largest
percentage gains in the service industries (Tampa Bay Regional Planning Council, 1999).
Government (10.67) had the second highest percentage of employment in the 1999 survey.
Agriculture was the least represented employment category (1.47 percent) in the region. Overall,
agriculture uses comprise 87,430 acres, or 49.7 percent of the total Little Manatee River
watershed area.
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Table 2.1 1995 Land Use/Land Cover for the Little Manatee River Watershed
Land Use/Land Cover Total Acres Percent
Urban and Built
Agriculture
Rangeland
Upland Forests
Water
Wetlands
Barren Land
Utilities
21,031
87,430
13,341
15,939
5,055
30,047
98
2,987
12.0%
49.7%
7.6%
9.1%
2.9%
17.1%
0.1%
1.7%
TOTAL 175,928 100
Source: SWFWMD Geographic Information System.
2.6 Transportation
Interstate Highway 75 (I-75), situated in the western half of the Little Manatee River watershed, is
the major north-south corridor through Manatee and Hillsborough counties. Other major northsouth
thoroughfares include U.S. Highways 301 and 41 and I-275. Major east-west highways in
the watershed are State Highway 674, connecting U.S. 41 to State Road 37, and State Highway 62,
connecting U.S. 301 to State Road 37.
Manatee County provides public transportation in some of the urban areas within its boundaries.
Rail service is provided by CSX Railroad. Port Manatee is a regional port facility in the watershed.
A major gas pipeline is proposed for this area, and is expected to run from the port to the east,
along the SR 62 corridor. The watershed contains no regional airport.
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CHAPTER III. WATER SUPPLY
INTRODUCTION
The assessment of available water supplies is closely linked to the predominant types of water use
within a region. The Little Manatee River and adjacent coastal areas have been the site of
extensive groundwater use in recent decades, primarily for agricultural supplies with lesser
quantities for municipal and industrial supplies. Due to problems with saltwater encroachment in
the groundwater system, special regulatory measures have been developed for the Southern
Water Use Caution Area (SWUCA) which includes the Little Manatee River watershed and
surrounding coastal areas. In contrast, surface water use in the watershed is very limited, being
largely restricted to a permitted withdrawal from the river by Florida Power and Light Corporation
(FP&L). Information on the distribution of ground and surface water-use in the Little Manatee
River watershed and adjacent coastal areas is presented in the following sections, along with
discussion and recommended actions pertaining to water use and supply issues in the region.
3.1 Water Use
3.1.1 Groundwater Use
The Little Manatee River watershed covers an area where there are many groundwater
withdrawals from the Floridan and intermediate aquifers. Although no major public supply
wellfields are permitted within the watershed, much of the agricultural, mining and industrial
groundwater withdrawals in southern Hillsborough and northern Manatee counties are located
within the Little Manatee River watershed. The major source of potable water supplies in the
region is the South-Central Hillsborough Wellfield, which is located in the Alafia River watershed.
This facility serves the County South-Central Hillsborough Water Demand Planning Area which
includes the communities of Ruskin, Wimauma and Sun City Center. Potable water supplies for
other citizens in the Little Manatee River watershed are provided by small domestic wells. (See
Atlas map 13 for the distribution of public groundwater supply sources.)
An estimated 49.7 million gallons per day (mgd) of ground water was withdrawn from the Little
Manatee River watershed in 1998. Table 3-1 summarizes 1998 withdrawals by source and use.
The largest groundwater use category in the watershed is agriculture, which accounted for 84
percent (41.9 mgd) of the total groundwater use. The second largest groundwater use is for
recreation (golf courses), which accounted for 10 percent (5.1 mgd) of the 1998 water use. The
combined mining/dewatering, commercial/industrial, and public supply categories totaled
approximately 2.7 mgd during 1998. Atlas map 14 provides 1998 estimated daily average
withdrawals.
3.1.2 Surface Water Use
Surface waters permitted for water supply include two small agricultural permits on tributaries to
the Little Manatee River and a large permit agreement for withdrawals from the main stem of the
river issued to Florida Power and Light Corporation. The permit agreement with FP&L, which was
established in 1973, allows withdrawals from the river for power plant cooling water at their
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Manatee Electrical Power Generation Plant. The withdrawal schedule allows for diversions from
the river of up to 40 percent of flow, but withdrawals have generally been very intermittent since
the plant has been in operation. Between 1978 and 1994, withdrawals had averaged about 7.7
mgd, or about 9 percent of the average flow of the river at that site. Rainfall can provide much of
the needed cooling makeup water; river withdrawals for the power plant averaged 0.3 mgd during
1998 (Table 3.1). The withdrawal schedule for the power plant under its existing operations
should be reviewed to better protect the Little Manatee River.
Table 3-1. 1998 Water Withdrawals in the Little Manatee River Watershed.
Use Sector
1998
Groundwater
Withdrawals
(mgd)
1998
Surface Water
Withdrawals
(mgd)
1998
Total
Withdrawals
(mgd)
Percent
of
Total
Agriculture (1) 41.0 0.9 41.9 84 %
Commercial/
Industrial
Mining/
Dewatering
0.4 0.3 0.7 2 %
1.0 0.2 1.2 2 %
Public Supply 0.6 0.2 0.8 2 %
Recreation 1.9 3.2 5.1 10 %
Total 44.9 4.8 49.7 100 %
Source: SWFWMD, 1999.
3.1.3 Reclaimed Water
In addition to traditional ground and surface water sources, approximately 2.04 mgd of reclaimed
water was used in 1996 (SWFWMD, 1997). Reclaimed water is water that has received at least
secondary treatment and is reused after being treated at the Hillsborough south-county domestic
wastewater treatment facility. Reclaimed water provides many benefits, most notably by
providing an alternate source of water which offsets the demand for ground and surface-water
sources. Uses for reclaimed water include urban and agricultural irrigation, industrial processes,
and power plant cooling. Most reclaimed water in the Little Manatee River watershed is for
recreation (golf courses).
3.2 SOURCES OF WATER SUPPLY INFORMATION
A number of technical reports and planning documents pertaining to hydrologic and water supply
issues in the Little Manatee River watershed are summarized briefly below:
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3.2.1. District Water Management Plan
The July 2000 District Water Management Plan represents the first five-year update of the
Southwest Florida Water Management District’s “comprehensive plan.” This twenty-year
document is consistent with the requirements of Section 373.036, Florida Statutes and Section 62-
40.510, Florida Administrative Code, as well as the standard format devised by the five water
management districts, the Florida Department of Environmental Protection and the Executive
Office of the Governor.
The primary purpose of the document is to serve as a comprehensive guide to the District in
carrying out its water resource management responsibilities, including those for water supply,
flood protection, water quality and natural systems. The CWM process is considered one of the
many tools for implementation of this plan.
3.2.2 Surface Water Studies Related to Water Supply
The principal studies related to surface-water supplies have concerned the Florida Power and
Light’s Manatee electrical power plant. The initial studies of the power plant siting and the
feasibility of obtaining water from the Little Manatee River were conducted in the early and mid-
1970s (Brown and Root, 1973; FP&L, 1979). The uses of the river by the power plant were
extensively reexamined with regard to the proposed conversion to orimulsion fuel. These
analyses were first presented in the site certification application (FP&L, 1995a). After the site
certification was submitted, FP&L agreed with the Southwest Florida Water Management District
to re-evaluate the withdrawal schedule for the river so that it provided a greater degree of
protection for the river. These studies (FP&L, 1995b) were submitted to the state of Florida in
support of the public hearing associated with the site certification. The District staff report to the
state also provides details on the development of the withdrawal schedule and the use of
groundwater and reclaimed water for the power plant. However, since the use of orimulsion was
not approved by the Florida Cabinet, the findings of these studies were not applied and the FP&L
withdrawal schedule from the river remains as initially permitted in 1973.
3.2.3 Groundwater Studies Related to Water Supply
The SWFWMD contracted an assessment of the water resources and management
recommendations in the Alafia and Little Manatee river basins (Dames and Moore, 1975). The
SWFWMD has performed a regional water resource assessment project for the Eastern Tampa Bay
area, which includes much of the Little Manatee River watershed (SWFWMD, 1992).
Groundwater withdrawal drawdown effects on the surficial, intermediate, and Floridan aquifers
within the Little Manatee River watershed were addressed in a computer model of the Brandon
urban dispersed wellfield (SDI, Incorporated, 1998). The wellfield’s effects on Lithia Springs and
the flow in the Alafia River were addressed during these evaluations.
A hydrobiological study of the Little Manatee River conducted in the late 1980s found there was
increasing baseflow in the main stem of the river and certain tributaries in the watershed (Flannery
et al, 1991). The study concluded the source of this baseflow was excess irrigation water that is
not used by the crops. These findings indicate there is a considerable amount of water savings
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that can be accomplished in the watershed through the use of more efficient agricultural water use
practices.
The Southern Water Use Caution Area Information Report provides a concise summary of the
history, current conditions and future plans for the Southern Water Use Caution Area within the
District. It describes the background leading to the designation of the area, management activities
such as the SWUCA Rule and challenges to it, where the District is today in its planning and the
approach to assuring water resource management and protection. The Little Manatee River CWM
area lies entirely within the SWUCA. Parts of it are within the Most Impacted Area (MIA), an area
in the SWUCA where no new Floridan aquifer withdrawals are allowed, as well.
3.2.4 Hydrologic and Water Use Data Sources
Local, regional, and state agencies compile data pertaining to ground and surface-water resources
in the Little Manatee River watershed. The District has a comprehensive hydrologic conditions
monitoring program. Conditions that are monitored include rainfall, evaporation, lake levels,
groundwater levels, spring flow, water quality, and river discharge and stage elevation. Atlas map
6 depicts hydrologic monitoring sites located within the Little Manatee River watershed.
Hydrologic data are also collected by the District through regulatory permitting requirements.
Public supply permittees and all permittees located in water use caution areas must report ground
and surface water withdrawals where permitted withdrawals exceed 100,000 gallons per day (gpd)
Annual Averages. Other water use permittees are required to report pumpage if permitted
withdrawals are greater than 500,000 gpd Annual Averages. Selected water use permittees are
also required to report water levels and water-quality data. The United States Geological Survey
also maintains a data base of stage, flow, and water-quality measurements which include
monitoring sites within the Little Manatee River watershed.
3.3 OUTSTANDING PERMITTING ISSUES
3.3.1 Surface Water Use
The District has scheduled the establishment of minimum flows for the Little Manatee River in
2006-2015. Minimum flows are defined as in Florida Statutes as “the limit at which further
withdrawals would result in significant harm to the water resources or ecology of the area (F.S.
373.042). The establishment of minimum flows will have a major effect on the availability of
additional water supplies from the Little Manatee River.
Another project that may affect surface water resources in the Little Manatee River basin is the
Enhanced Surface Water Supply system that has been proposed by Tampa Bay Water. This plan,
which will be compared to other alternative water supply sources, calls for waters from the Alafia
River, the Hillsborough River and the Tampa Bypass Canal to be diverted to an offstream surface
water reservoir in southern Hillsborough County.
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Finally, the expanded mining of phosphate in the eastern portions of the watershed by IMC-
AGRICO will alter a significant portion of the Little Manatee River watershed. Issues related to
phosphate mining are summarized in Section 6 of this chapter on water supply.
3.3.2 The Southern Water Use Caution Area
The outstanding groundwater issue is the Southern Water Use Caution Area. The SWUCA was
declared a “water use caution area” in 1992 by the District Governing Board, encompassing an
area of about 5,100 square miles covering the southern half of the District. Water resource
concerns associated with the SWUCA involve the decline of lake levels along the Highlands Ridge
and advancing coastal saltwater intrusion in the Floridan aquifer. A Water Use Caution Area
(WUCA), also known as a Water Resource Caution Area (WRCA), is defined by State law as an
area where water resources are, or are expected to, become critical within the next twenty years.
A number of WRCAs exist throughout the State, including several in the Southwest Florida Water
Management District.
3.3.2.1 SWUCA Background
The mission of the District is to manage and protect water resources for human and
environmental needs. This is accomplished through both regulatory and non-regulatory means,
including but not limited to, water resource development, water use and environmental resource
permitting, comprehensive hydrologic monitoring and long-range planning. During the mid to late
1980s, long-term declines in hydrologic conditions were observed in three specific geographic
regions of the District: Highlands Ridge, Northern Tampa Bay and Eastern Tampa Bay. More
intensive data collection and analysis (i.e., a Water Resource Assessment Project, or WRAP) were
initiated in each area to ascertain the probable causes of the declines and the modified or new
resource management programs that might be needed.
Each area was designated as a WUCA in 1989 and specific water use permitting rules were
implemented for the Highlands Ridge (HR) and Eastern Tampa Bay (ETB) WUCAs in 1990. Major
rule provisions emphasized water conservation and water use monitoring, including per capita
goals for public suppliers, crop efficiency standards for agriculture and specific conservation plans
for recreation, industrial and mining uses. Metering was also required for all uses greater than
100,000 gallons per day.
The decision to create the HR and ETB Water Use Caution Areas was subsequently validated by
the district-wide Needs and Sources Report (1992). This report showed the greatest projected
increase in water use by 2020 would be in the southern part of the District, where significant
stress already existed on the Floridan aquifer. It also verified that current and anticipated
demands would create water resource problems in the Highlands Ridge and Eastern Tampa Bay
WUCAs that need to be addressed.
The results of the Eastern Tampa Bay WRAP Report showed that groundwater resources of the ETB
and HR Water Use Caution Areas are interdependent and must be addressed from a basin-wide or
regional perspective. This led to the establishment of the Southern Water Use Caution Area in
1992, encompassing the two existing WUCAs and the area between them. Specifically, the
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SWUCA encompasses an area of about 5,100 square miles and covers the southern half of the
District, including all of Manatee, Sarasota, Hardee and DeSoto counties and portions of
Hillsborough, Charlotte, Highlands and Polk counties.
The water resource concerns associated with the SWUCA involve the decline of lake levels along
the Highlands Ridge and advancing saltwater intrusion in coastal regions. Data show the
potentiometric surface in the Floridan aquifer has declined significantly during the past 40 years.
Information provided by USGS reveals seasonal declines as great as 50 feet in 1989. Water quality
monitoring shows increasing trends for sulfates, total dissolved solids and chlorides across the
coastal counties. Many lake levels in the Highlands Ridge area have also declined significantly, in
some cases as much as 20 feet.
3.3.2.2 1994 SWUCA Rule
In 1993, the District, local representatives of agribusiness, public supply, industry, the
environmental community and local and regional governments began work on a SWUCA
management plan. Monthly meetings set the course for balancing water demand with the ability
of the resource to meet that demand. A management plan was completed in April, 1994. This
was followed by public meetings starting in June, 1994 in communities across the multi-county
SWUCA to gather public comment on proposed water management rules which would implement
the minimum aquifer level, the primary means through which groundwater sustainability was to
be achieved.
In considering where to set the minimum level, the District’s Governing Board assessed three
options:
Return the saltwater interface to a historical position closer to the coast;
Significantly reduce the rate of landward saltwater intrusion; or
Maintain the status quo.
After a great deal of debate and consideration of a number of scientific, social and economic
issues, the Board decided on option 2) and directed staff to prepare a rule to effect such a result.
The objectives of the rule that followed were clearly delineated. The first was to preserve the
freshwater resources of the Floridan aquifer and stabilize lake levels in Polk and Highlands
counties. The second was to limit the impact of the proposed regulations on the region’s
economy and existing users.
The District’s approach to the SWUCA dilemma included:
1) Using a minimum aquifer level to prevent the withdrawal of new quantities from the
Floridan aquifer;
2) Allowing new uses to obtain water through reallocation and development of alternative
sources;
3) Phasing additional conservation requirements to gradually reduce existing permitted
quantities; and
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4) Providing incentives and funding for development and use of alternative sources.
It is important to note there were two distinct steps taken to institute the minimum level.
The first was to establish the proper minimum level through years of data collection and
scientific analysis. The second was preparation of a plan to achieve this level by
considering environmental, technical and socioeconomic aspects of the imposition of such
a rule.
An innovative and controversial aspect of the SWUCA Rule was reallocation, a mechanism
intended to reduce impacts of the Rule on existing and future permittees. Since new quantities
would not be permitted when the water level was below the minimum level, the rules provided
for reallocation to move permitted water between users to less stressed areas as an alternative to
the competing applications provisions in Chapter 373, Florida Statutes.
The SWUCA Rule also included higher efficiency standards for users, a requirement for water
conserving rate structures and groundwater withdrawal credit permits to encourage the use of
alternative source water. Also significant, were water conserving credits for agriculture; the first
time a water management district in Florida incorporated a conservation incentive into the
permitting process.
When the proposed rule was published for adoption in December 1994, the District received
notice of 26 challenges to the rule. After a series of discussions and resulting rule clarification
changes, most of the agribusiness challenges were withdrawn. The resulting hearing lasted a total
of nine months, due in part to a challenge to the District’s entire water use permitting program
along with the changes associated with the SWUCA.
3.3.2.3 The Final Order
In March 1997, the District received the administrative law judge’s Final Order on the challenges
to the District’s Southern Water Use Caution Area rules. The Order also addressed the existing
water use permitting rule challenges that were consolidated with the hearing on the proposed
SWUCA rules.
The Order, which took about one year for the judge to write, followed a hearing that was the
longest in the Division of Administrative Hearings’s (DOAH) history. The administrative law judge
found the following proposed rules valid:
1) Minimum Floridan Aquifer Level. The judge upheld the science that was used to establish the
level, and found that socioeconomic factors could be balanced with science in establishing the
minimum level.
2) Conservation Phase In. Existing permits are subject to being reduced, but gradually over a tenyear
phase-in period. All permittees must achieve heightened water use efficiency through
measures specific to use types.
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The administrative law judge found the following proposed rules invalid:
1) Preferential Treatment of Existing Users. The proposed rules would have allowed the District
to treat renewal applications and permit applications for new quantities differently. The District
proposed to renew permits but deny new quantities when the potentiometric surface was below
the established minimum. The judge found that applications for new quantities and renewal
quantities must be treated the same under Chapter 373, F.S., unless such preference comes from
the Legislature. Further, he found there is no vested right to a continuation of water use after
expiration of a permit outside the competing use statute.
2) Reallocation. The judge found that specific legislative authority is needed before the District
could authorize water users to determine the allocation of scarce water supplies.
3) Reuse and Desalination Investigations and Determinations of Feasibility. The judge
determined that the District does not have the authority to determine whether development by
the applicant of a reuse or desalination system is economically, technically and environmentally
feasible.
With respect to reuse, the judge concluded that while Chapters 373 and 403, F.S., recognize reuse
as a desirable goal, the decision whether to construct the necessary facilities was specifically left
to the utilities, and not the District.
As to desalination, the judge found authority for the District to investigate and implement
desalination on its own but not to shift the responsibility for developing desalination to certain
public supply applicants through the water use permitting process.
4) Separate Permits for Wholesale Public Supply Customers. The proposed rules would have
required wholesale public supply customers (i.e., a water utility without its own source of water
that receives water from a permitted public supplier) to obtain a separate water use permit as a
way of implementing conservation measures and other permitting conditions. The judge found
the District does not have the legal authority to require an individual or entity receiving water from
a permittee to obtain a separate permit.
In summary, the District’s approach had evolved into a complex, integrated set of proposed rules
designed to work in conjunction with each other to accomplish the SWUCA objectives. The
deletion of certain key provisions had the effect of creating an ineffective, even counterproductive
result. The District, like all those involved, had the option of appealing all or part of the ruling.
3.3.2.4 Appeal of the Final Order
In October 1997, the Governing Board moved to appeal three specific components of the ruling,
and withdrew the minimum aquifer level. The three parts of the ruling to be appealed include the
provisions to:
1) require the investigation and, where feasible, implementation of reuse;
2) require the investigation and, where feasible, implementation of desalination; and
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3) require wholesale public supply customers (i.e., a water utility without its own source of water
that receives water from a permitted public supplier) to obtain a separate water use permit to
implement conservation measures.
The withdrawal of the minimum level, even though upheld by the judge, was the result of a part of
the Rule that linked the intended level to the provisions for reallocation and treatment of renewals
differently than new applications. This has been called the “three-legged stool,” and was an
important part of gaining permittee support for the original rule. The failure of two of its “legs”
resulted in the need to withdraw and reevaluate the minimum level in its present form. This
temporary withdrawal of a minimum aquifer level does not negate the District’s ability to utilize
the previously established water use permitting rules for the Eastern Tampa Bay, and Highlands
Ridge WUCAs which remain in effect. In addition, a comprehensive reevaluation of the SWUCA
management approach is well underway.
As of September 2000, an appeal court has ruled in favor of the District on all 13 points on appeal
in the historic SWUCA case. Among the findings, the court determined that:
the District has the authority to require water use permit holders to investigate the feasibility of
using reclaimed water as part of their water use requirements;
the District has the authority to require water use permit holders to investigate the feasibility of
using desalination where it is environmentally and technically feasible;
the District has the authority to require water supply utilities to adopt "water conservation rate
structures" which require heavy users to pay more for their water;
the District has the authority to require a wholesale customer of a public supply permittee to
obtain a permit so that the District's per capita water use criteria can be enforced;
the terms "unacceptable," "adverse" or "significant" are scientific determinations allowing for the
use of professional judgment by District staff on a site-specific basis;
the District's criteria for issuing permits provide sufficient direction to determine acceptable
mitigation for impacts to resources; and
the District has the authority to require that all 14 of the District's conditions for issuance be
met before a permit is granted.
3.3.2.5 The Future of SWUCA
The conditions that resulted in the need for specialized water resource management in the
SWUCA have not gone away. Saltwater intrusion persists and lowered lake levels remain. Seeing
a window of opportunity created by changing circumstances, the Governing Board has determined
there is a need to re-evaluate its management plan in light of recent court rulings. This
opportunity is based on a number of factors:
• significant portions of the SWUCA Rule were ruled invalid by an Administrative Law Judge;
• a reduction in groundwater usage has occurred since the SWUCA process began, resulting
in lower water use projections for the future;
• aquifer levels have recovered in most areas to the minimum level proposed by the earlier
plan; and
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• 1997 legislation on minimum flows and levels allows a “recovery strategy” when actual
levels are below the minimum levels.
The District took several actions during 1997 to initiate an effective reevaluation of conditions and
management in the SWUCA. In May, a statewide SWUCA Discussion Group made up of water
resource experts generally not involved with the previous efforts was convened to brainstorm
alternative approaches to resolve the problems of the area. This was followed in June by two
public workshops in Bartow and Bradenton to brief affected parties and the general public on the
latest developments and to seek feedback. Then, in September came the formation of a staffbased
SWUCA Team with a broad charge to revisit previous management efforts and try to build a
consensus around a cooperative approach to maintaining sustainable water supplies.
The SWUCA Team’s focus is on:
• carefully refining the issues to be addressed, including the development and
implementation of a resource management program which protects water and related
natural resources while maximizing water supply;
• identifying regulatory and non-regulatory alternatives for cooperative management;
• evaluating and modifying the minimum aquifer level as needed;
• forming a work group of affected parties to assure full involvement;
• developing the prevention/recovery strategy for the area;
• coordinating with other water districts, FDEP, the Department of Agriculture and
Consumer Services and others; and
• maintaining ongoing communication with the District’s Governing and Basin boards,
advisory committees and other appropriate parties.
As previously mentioned, during its 1997 session, the Florida Legislature amended the Water
Resources Act (s. 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 similar to the
previous Needs and Sources Report, 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 District developed the RWSP 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 proved quite useful in identifying data gaps or other ways to improve the
RWSP process and results. For example, estimation of future agricultural water needs has
benefitted from the involvement of the District's Agricultural Advisory Committee and specific
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trade organizations. In addition, the RWSP contains a five-year work program for the
implementation of water resource development projects.
The SWUCA management approach includes not only completion and implementation of the
RWSP, but the establishment of MFLs and any accompanying recovery and prevention strategy.
With respect to MFLs in the Little Manatee River watershed, minimum flows for the Little Manatee
River system are scheduled for adoption by December 2015. The District continues to monitor
the effects of lowered groundwater levels throughout the region on movement of the
freshwater/saltwater interface and declining lake levels. Minimum levels for the upper Floridan
aquifer in the SWUCA are scheduled for adoption by December 2001, and for the intermediate
aquifer by December 2005.
Figure 3-1 depicts special water use designations with the Little Manatee River watershed.
3.4 GOVERNMENTAL ACTIVITIES AND OTHER INITIATIVES
The section below describes other governmental activities in the Little Manatee River Watershed
that are related to water supply.
3.4.1 Southwest Florida Water Management District
The District is conducting numerous activities which pertain to water supply in the Alafia River
watershed. One of these is to provide funding for the development of alternative water sources.
The District's New Water Source Initiative (NWSI) Program will fund up to 50 percent of the cost
of alternative water sources which have regional water resource benefits. The Central
Hillsborough Reuse System and seawater desalination initiatives in the Alafia River basin have
received funding under NWSI. The District also provides funding for new water sources through
the Cooperative Funding program and through Basin board initiatives, which are used for a
broader scope of projects.
In 1998, the District, Tampa Bay Water, and its member governments developed a Partnership
Plan. Under the Partnership Plan, the District will provide $183 million in funds to Tampa Bay
Water to assist in developing alternative water sources. These sources are needed to alleviate
environmental impacts caused by existing groundwater withdrawals and to meet the future needs
of the tri-county area. Sources identified in the Partnership Plan include reclaimed water, purified
water, and seawater desalination. The Partnership Plan also calls for a reduction of 17 mgd in
water use through demand management, with the District Basin boards providing $9 million a
year through cooperative funding.
The Alafia River and Manasota Basin Boards are helping to address water supply issues. The Alafia
Board has teamed up with the other two Basin boards in Hillsborough County and local
cooperators, for example, to assure implementation of the Tampa Bay Partnership Agreement.
The Manasota Basin continues fund a substantial number of reclaimed water and agriculture
conservation projects in the SWUCA and MIA in Manatee County.
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3.4.2 Florida Department of Environmental Protection Waterbody Classification
The Little Manatee River below State Road 674 has been designated as an Outstanding Florida
Water. As such, special permitting criteria are used by the Florida Department of Environmental
Protection for activities that might impact the water quality of the river. This section of the river
below US Highway 301 is also designated as an aquatic preserve, which has implications for
various types of activities on and along the river.
3.4.3 Tampa Bay Water (formerly West Coast Regional Water Supply Authority)
Tampa Bay Water’s mission is to provide members with reliable supplies of high-quality water to
meet present and future needs in an environmentally and economically sound manner. Tampa
Bay Water is a special state district created by interlocal agreement among member governments
-- Hillsborough County, Pasco County, Pinellas County, St. Petersburg, New Port Richey and
Tampa. The agency provides wholesale water to its member utilities, who in turn provide water to
nearly two million people in the tri-county area. Tampa Bay Water was created in 1998, with
assistance from the Florida Legislature and Governor, by restructuring the West Coast Regional
Water Supply Authority.
Tampa Bay Water provides an average of 176 million gallons of water. Currently, that water is
produced from 12 regional groundwater facilities. Tampa Bay Water also owns and operates two
water treatment facilities and one surface water augmentation facility. With a staff of 104, Tampa
Bay Water is able to provide quality water at an affordable wholesale rate.
Tampa Bay Water is committed to environmentally sustainable water supplies. By 2003, they will
reduce groundwater production at 11 interconnected facilities in Pasco and northern Hillsborough
counties from a current permitted level of 158 million gallons per day to 121 million gallons per
day. By 2008, pumping from existing facilities will be further reduced from 121 million gallons
per day to 90 million gallons per day. New water supplies must be developed to accommodate
these pumping reductions while still meeting the members’ needs. To plan for new water
supplies, Tampa Bay Water developed a Master Water Plan that combines new sources such as
desalinated seawater and surface water with limited additional groundwater and aggressive
conservation. These Master Water Plan projects will ensure adequate supplies for the Tampa Bay
region through the year 2010 and beyond.
3.4.3.1 Resource Development Plan
As discussed previously, Tampa Bay Water has formulated a Resource Development Plan. The
plan identifies the need for new water sources to meet the public supply demands of the
tri-county region (WCRWSA, 1994). Potential sources cited in the plan include ground water,
surface water, storm water, reclaimed water, brackish water and seawater desalination, and interregional
sources.
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3.4.3.2 Tampa Bay Water’s Master Water Plan
The Master Water Plan, as originally approved in December 1995, comprised the development of
85 mgd of new supply and three pipeline inter-ties in two phases, further evaluation of three
alternative water projects, and a conservation program to save 17 mgd over the 10-year
development period. The Master Water Plan was subsequently revised by Board action in
November 1998. The revised plan currently includes the following new supply projects in three
categories, as may be subsequently modified by the Authority Board pursuant to the permitting
procedures established in the inter-local agreement.
Selected for Final Design (Stage B) and Construction
Enhanced Surface Water System - Supply from Tampa Bypass Canal, Alafia River and
Hillsborough River High Water with shared conveyance (South-Central Hillsborough Intertie),
storage (Tampa Bay Regional Reservoir) and treatment (Tampa Bay Regional Surface
Water Plant) facilities.
Brandon Urban Dispersed Wells - Select redevelopment of groundwater supply in the
Brandon area.
Seawater Desalination - Privatized development of 25 mgd supply at Big Bend.
Potential New Supply for Studies, Testing, and Preliminary Design (Stage A)
Brackish Water Desalination - Continued evaluation of opportunities for development of
brackish water supplies.
Cone Ranch & Dispersed Wells - Project to develop long-planned available groundwater
supply in Northeast Hillsborough County in conjunction with hydrologic restoration.
Cypress Bridge II - Ongoing evaluation of operating and monitoring data for the Cypress
Bridge Wellfield, which straddles Hillsborough and Pasco Counties, for potential 4 mgd
increase in production above current permitted capacity through a new/additional permit
on existing or expanded facilities.
Developmental Alternatives (Concept Development and Preliminary Discussions)
Seawater Desalination II - Consideration of development of additional supply utilizing
seawater desalination.
3.4.4 Peace River/Manasota Regional Water Supply Authority
The Peace River/Manasota Regional Water Supply Authority (PR/MRWSA) has become increasingly
important for future water supply planning and development in the region. The PR/MRWSA is
made up of four-counties: Manatee, Sarasota, Charlotte and DeSoto. A major, ongoing initiative
of the authority is the NWSI-funded Peace River Option, which involves expanding the treatment
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capacity of the Peace River facility from 12 mgd to 24 mgd, constructing 11 additional aquifer
storage and recovery (ASR) wells and transmission lines to interconnect the major public water
utilities in Charlotte, DeSoto and Sarasota counties. Although this project will not provide water
to Manatee County, it will reduce Sarasota County’s reliance on the County for water supplies. In
the future, PR/MRWSA is expected to continue to be instrumental in forging regional projects,
such as the Peace River Option, for addressing long-term water needs.
3.4.5 FDEP Ecosystem Management Initiative
Ecosystem management as defined by the Florida Legislature in House Bill 2111 is:
“a concept which includes coordinating the activities of state and other
governmental planning, land management, environmental regulatory programs,
and voluntary programs, together with the needs of the business community,
private landowners, and the general public, as partners in a streamlined and
effective partnership for the protection of Florida’s environment.”
There are no ongoing or proposed ecosystem management initiatives in the Little Manatee River
watershed.
3.4.6 Tampa Bay Surface Water Improvement and Management Plan
In recognition of the need for additional emphasis on the restoration, protection and management
of the surface water resources of the State, the Florida Legislature, through the Surface Water
Improvement and Management (SWIM) Act of 1987, directed the state's water management
districts to "design and implement plans and programs for the improvement and management of
surface water" (Section 373.451, F.S.). The SWIM legislation requires the water management
districts to protect the ecological, aesthetic, recreational, and economic value of the state's surface
water bodies, keeping in mind that water quality degradation is frequently caused by point and
non-point source pollution, and that degraded water quality can cause both direct and indirect
losses of habitats.
In accordance with the law and strongly supported by the Tampa Bay Regional Planning Council’s
Agency on Bay Management (ABM), the Southwest Florida Water Management District selected
Tampa Bay as its top priority waterbody for the SWIM Program. A management plan was
originally prepared and approved in 1988 based on The Future of Tampa Bay, a management plan
generated from the 1985 Tampa Bay Management Study Commission. The SWIM Plan was
revised in 1992, and is now under consideration for another update.
The Tampa Bay SWIM program’s strategies for protection and restoration are based on ABM and
Tampa Bay Estuary Program’s (TBEP) previous activities and the Comprehensive Conservation
Management Plan (CCMP) for Tampa Bay. In fact, much of the supporting information for the
SWIM plan was taken verbatim from The Future of Tampa Bay and the CCMP. In preparing the
SWIM Plan, staff reviewed the goals, initiatives, and strategies for restoring and protecting Tampa
Bay in the CCMP and then focused on activities identified for the District that can be
accomplished within the legislative charge of SWIM.
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The District has many tools available to implement the legislative intent of the SWIM program,
including but not limited to, integrated planning and coordination, regulatory authority, land
acquisition programs and the SWIM program itself. Each of these areas provides opportunities to
assist in the management of Tampa Bay, one of the prominent natural systems within the District.
With adequate funding and implementation, the SWIM Plan for Tampa Bay will be one of the
vehicles through which the District and the state of Florida contribute to ongoing efforts to restore
and protect Tampa Bay.
3.4.7 Tampa Bay Estuary Program
The Little Manatee River drains into Tampa Bay, which is one of 22 estuaries in the United States
that are a part of the National Estuary Program (NEP). The NEP was created under the Clean
Water Act and is administered by the USEPA. The Tampa Bay Estuary Program (formerly Tampa
Bay National Estuary Program) was established in 1991 to assist the community in developing a
comprehensive plan to restore and protect Tampa Bay. The management committees are
composed of private and public agencies and organizations. The document, "Charting the Course"
management plan outlines the proposed action plans to address water and sediment quality, and
natural systems issues in Tampa Bay and its watershed (TBEP 1996).
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3.5 ACTION PLAN: WATER SUPPLY
ISSUE #1: WATER LEVEL DECLINES AND WATER QUALITY DEGRADATION ASSOCIATED
WITH GROUNDWATER WITHDRAWALS
BACKGROUND:
The water resource concerns associated with the SWUCA involve the decline of lake levels along
the Highlands Ridge and advancing saltwater intrusion in coastal regions. Data show the
potentiometric surface in the Floridan aquifer has declined significantly during the past 40 years.
Information provided by the USGS reveals seasonal declines as great as 50 feet in 1989. Water
quality monitoring shows increasing trends for sulfates, total dissolved solids and chlorides across
the coastal counties. Many lake levels in the Highlands Ridge area have also declined significantly,
in some cases as much as 20 feet.
STRATEGY:
Carefully refine the issues to be addressed, including the development and implementation of a
resource management program which protects water and related natural resources while
maximizing water supply; identify regulatory and non-regulatory alternatives for cooperative
management; evaluate and modifying the minimum aquifer level as needed; form a work group of
affected parties to assure full involvement; develop the prevention/recovery strategy for the area;
coordinate with other water districts, FDEP, the Department of Agriculture and Consumer
Services, and others; and maintain ongoing communication with the District’s Governing and
Basin boards, advisory committees and other appropriate parties.
ACTIONS:
In the short term, the District will:
1. Continue using existing water use permitting rules for the Eastern Tampa Bay and
Highland Ridge WUCAs. District-wide rules will continue to be stringently applied in the
balance of the SWUCA.
2. Anticipate demand for groundwater will exceed the quantities available in at least portions
of the SWUCA, and develop and adopt a “Competing Applications Rule.”
3. Develop revised SWUCA Rule as part of an overall management strategy. This will include
reestablishment of minimum levels, possible use of components from the original SWUCA
Rule that were not challenged (e.g., water conserving credits for agriculture, ground water
withdrawal credits for use of alternative sources, heightened efficiency standards for all
users, etc.) and revisions to some of the SWUCA Rule language to accommodate
suggestions of the Judge.
4. Appeal three specific components of the SWUCA ruling (see earlier listing).
5. Continue forward with water supply planning efforts such as the “Regional Water Supply
Plan” for the SWUCA. Existing water resource development efforts will be enhanced
pursuant to Chapter 97-160, Laws of Florida, so as to create effective partnerships with
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local governments, utilities, agriculture, the regional water supply authority and others to
meet present and future water supply needs.
6. Establish an outreach program to re-engage the affected and interested public. The
primary objectives will be to inform and involve, disseminating information on water use
trends, projected uses and resource management decisions, while gaining effective
feedback such as assessment of revised and new rule proposals and input on the intent of
comprehensive monitoring programs.
This overall interim strategy is intended to allow water use permit renewals and some new
permits in parts of the SWUCA. Most of the associated quantities are expected to be offset by
reductions in permitted quantities due to heightened water use efficiency requirements,
retirement of some permits and continuing cooperation of user groups in achieving water
conservation (e.g., industrial process improvements, public supply per capita reductions and best
management practices among agriculture and recreational users cited earlier in this report).
In the longer term, the District will continue to use and refine the short term approaches,
including:
1. Implementation of the revised SWUCA Rule and associated minimum levels as part of an
overall recovery strategy.
2. Application of the Competing Applications Rule as needed.
3. Improvement of the detailed monitoring system necessary to identify trends and
understand the resource.
4. A commitment to develop alternative water supply sources (e.g., reuse of storm water and
wastewater, aquifer storage/recovery, sustainable use of surface water and water
conservation).
RESPONSIBLE PARTIES: SWFWMD, Tampa Bay Water, local governments and the Florida
Cooperative Extension Service.
TENTATIVE SCHEDULE:
1. Develop Competing Applications and SWUCA rules in 2003-2005.
2. Implement rules by 2005.
EXPECTED BENEFITS: Reduction of ground and surface water impacts in the SWUCA.
The following are major District projects addressing this issue.
Project: Water Supply & Resource Development Fund
In 1997, the Florida Legislature amended the Water Resources Act to clarify the water
management districts’ responsibilities relating to water supply planning and water resource
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development. Specifically, the water management districts were directed to complete a districtwide
water supply assessment by July 1, 1998. Further, the districts were to develop regional
water supply plans for regions where demands are expected to exceed available supplies by 2020.
The SWFWMD regional water supply plan encompasses a ten-county area extending from Pasco
County in the north to Charlotte County in the south. This region encompasses the northern
Tampa Bay region and the Southern Water Use Caution Area. The reserves for water supply and
resource development will be used to cooperatively fund future water supply and resource
development projects to meet the needs identified in the regional water supply plan. Both the
Alafia and Manasota Basin Boards have set aside funds for this initiative.
Participants: Alafia and Manasota Basin Boards.
Status: Ongoing.
Project: Water Resource Water Supply Development -Surface Water and Stormwater.
This is a District funded study to determine the feasibility and availability of surface water and
stormwater to meet regional water supply needs to 2020 in the Southern Planning area. The
project consists of evaluating potential surface water and stormwater supplies by analyzing yields
from the major riverine systems in the planning area. A total of ten rivers were evaluated. A list of
63 projects was initially developed, and subsequently narrowed to the most likely to proceed list
of sixteen projects. The most likely projects were selected on their ability to provide significant
quantities of water to meet regional needs.
Participants: District.
Status: Ongoing.
Project: Manatee Agricultural Reuse Supply.
This project would interconnect the three sub-regional treatment plants, construct an
interconnected stormwater reuse facility and provide up to 12 mgd of reclaimed water primarily
for agricultural use. The project will provide reclaimed water for irrigation of residential,
recreational, and agricultural customers, thereby decreasing dependence on potable water. The
total reclaimed water flow would be 20 mgd.
Participants: Manasota Basin Board, District, Manatee County and Federal Grant.
Status: Ongoing.
Project: Lake Hancock Lake Level Modification.
Historically, Lake Hancock fluctuated more than a foot higher than it has during the past several
decades. This lowering was due to the dredging of the outfall canal in the early part of the last
century. Such dredging was common throughout Florida to allow for further use of marginal
lands. This project proposes to evaluate the impact of modifying or replacing the District’s outfall
canal structure so that water levels can be maintained at historical levels of approximately 100.5
feet National Geodetic Vertical Datum (NGVD).
Participants: District and Peace River, Manasota and Alafia River Basin Boards.
Status: Proposed.
Project: Peace River Option.
The Peace River/Manasota Regional Water Supply Authority owns and operates the Peace River
Water Treatment Facility on the Peace River in southern DeSoto County. Currently, water
diverted from the river may be stored in a 625 million-gallon-capacity off-stream reservoir, or
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treated and either distributed to customers or stored in the 9 existing ASR wells. This project will
expand the treatment capacity of the Peace River facility from 12 mgd to 24 mgd, construct 11
additional ASR wells, and construct transmission lines to interconnect the major public water
utilities in Charlotte, DeSoto, and Sarasota counties. The project is intended to meet projected
future demands of Charlotte County, DeSoto County, the City of North Port, and other areas of
Sarasota County served by Sarasota County Utilities, and will significantly improve rotational
capacity.
Participants: District, USEPA and Peace and Manasota Basin Boards.
Status: Ongoing.
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ISSUE #2: IMPROVED COORDINATION OF LAND AND WATER USE PLANNING
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 for water management decisions within its region and
is a centralized 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 is essential to accomplishing objectives in
both areas. This issue was the subject of the Governor’s Task Force on Land and Water Planning.
STRATEGY:
Work to have water supply as a consistency requirement for Local Government Comprehensive
Plans. Improve coordination between land and water planners.
ACTIONS:
1. Use the District’s Regional Water Supply Plan as the source document for water supply
availability. Develop a linkage mechanism between local governments.
2. Increase District involvement with the regional planning council and local government
planning departments. Develop an annual report summarizing the status of water supply,
water resources, and new regulations for distribution to local land use planners and
others. Develop memorandums of understanding between the District and local
governments which provide that local governments will give advance notice to the District
when developments of regional impacts and large comprehensive plan amendments are
proposed. Coordinate five-year planning documents, such as comprehensive plan updates
and Basin plans, on the same time frame.
RESPONSIBLE PARTIES: SWFWMD, Tampa Bay Water, Manatee County, Hillsborough County,
Manatee County, City of Palmetto, Peace River/Manasota Regional Water Supply Authority,
Hillsborough County City-County Planning Commission, Tampa Bay Regional Planning Council,
Environmental Protection Commission of Hillsborough County.
TENTATIVE SCHEDULE:
1. Implement Little Manatee Watershed Plan Land/Water Linkage Plan 2002-2006.
2. Coordinate the Regional Water Supply Plan with the upcoming updates of local
government comprehensive plans.
EXPECTED BENEFITS: Better coordination between land and water planning.
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The following are major District projects addressing this issue.
Project: Little Manatee Watershed Plan Land/Water Linkage.
The Little Manatee River Land/Water Linkage Project’s goal was to promote citizen and stakeholder
outreach, communication and education. The project accomplished this through facilitate
workshops with local citizens and stakeholders to identify preferences and priorities for District
and County planning and resource management initiatives. A report entitled “Little Manatee River
Watershed Plan Land/Water Linkage-Staff Report,” identifying specific strategies, projects and
priorities for the District’s Little Manatee River Comprehensive Watershed Management Plan and
the County’s growth management process, was completed as part of the project.
Participants: Hillsborough County, Alafia River Basin Board.
Status: Ongoing.
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ISSUE #3: AGRICULTURAL IRRIGATION FLOW TO STREAMS
BACKGROUND:
Previous studies have shown that some streams in the Little Manatee River basin receive flow
from agricultural irrigation. Increased streamflow may result from: direct runoff of excess
irrigation water, increased groundwater interflow resulting from supplementation of the surficial
aquifer with irrigation waters, or increased runoff after rainfall events due to saturated soil
conditions resulting from irrigation. Streamflow records in the Little Manatee River should be
evaluated to determine if excess agricultural irrigation waters continue to supplement flows in the
river and its tributaries. Periodic flow measurements should be done on ungauged tributaries (i.e.,
Carlton Branch, South Fork) that have been previously studied. Flow measurements at all sites
should be compared to water chemistry data to evaluate to what extent that deep ground waters
from irrigation are entering the streams. In areas where flow supplementation is occurring, best
management practices identified in the District’s agricultural exemption program should be
implemented. For those agricultural operations which may be exempt, implementation of these
programs should be encouraged.
STRATEGY:
Re-evaluate the extent that agricultural irrigation waters are flowing to streams in the Little
Manatee River watershed. If flow supplementation is occurring, identify problem areas and
implement best management practices to minimize irrigation runoff.
ACTIONS:
1. A series of streamflow measurements should be made on tributaries and the main stem of
the Little Manatee River in the dry season to determine if baseflow is being supplemented
by agricultural irrigation water. Water chemistry measurements should also be made to
determine if the mineral composition of the water is characteristic of surface or ground
water.
2. A geographic analysis should be done to identify sub-basins where land use may result in
flow supplementation.
3. In areas where flow supplementation is occurring, best management practices identified in
the District’s agricultural exemption program should be implemented where applicable.
Implementation of these programs should be encouraged for those agricultural operations
which may be exempt.
4. Opportunities for incorporation of BMPs into Land Development Code should be
evaluated and implemented where appropriate.
RESPONSIBLE PARTIES: SWFWMD, FDEP, Hillsborough County, Manatee County, Hillsborough
County City-County Planning Commission, Tampa Bay Estuary Program.
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TENTATIVE SCHEDULE:
1. Flow and water chemistry sampling during spring 2004.
2. Geographic analysis winter-spring 2004.
3. Identify sub-basins where flow supplementation in occurring in spring-summer 2005.
4. Pursue programs of best-management practice implementation.
EXPECTED BENEFITS: Conserve ground water resources, protect water quality and ecology of the
Little Manatee River.
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ISSUE #4: REVIEW STREAMFLOW MANAGEMENT CRITERIA FOR PHOSPHATE MINING
RECLAMATION PLANS
BACKGROUND:
Substantial areas in the eastern portions of the Little Manatee River watershed are being mined for
phosphate ore. Existing state reclamation criteria emphasize maintenance of pre-mining flooding
criteria, but make no mention of maintaining baseflow or average rates of runoff in the affected
streams. The industry has used the net ecosystem benefit permitting process, in other
watersheds, to improved methods and practices to minimize impacts to the resource. Also, the
FDEP’s Bureau of Mine Reclamation is revising its streamflow criteria for reclamation standards.
Although several mines in the Little Manatee River watershed have already gone through initial
permitting, resource managers should interact with the phosphate industry to identify improved
analyses that can be conducted to determine if streamflow will be significantly altered in the
mined sub-basins. Using such analyses, reclamation plans should be designed so that the entire
flow regime of the affected streams is altered as little as possible.
STRATEGY:
The sufficiency of existing regulations for phosphate mine reclamation should be reviewed to
determine if they protect important streamflow characteristics such as baseflow and average basin
runoff. If necessary, develop improved technical methods to evaluate the effect of mine
reclamation on streamflow. Interact with FDEP Bureau of Mine Reclamation in the revision of
streamflow criteria for mine reclamation. Reclamation plans should be designed so that historic
flow regimes in tributary sub-basins are maintained to the greatest extent practical.
ACTIONS:
1. Interact with the phosphate industry to examine technical tools that can be used to
evaluate the impact of phosphate mining and reclamation on streams in the Little Manatee
River basin. Determine if the industry is willing to pursue improved analyses to achieve a
net ecosystem benefit that will exceed current state permitting criteria.
2. Utilize improved hydrologic analyses to design reclamation plans that protect the entire
flow regime of tributaries in sub-basins to be mined.
3. Interact with FDEP Bureau of Mine Reclamation to revise existing regulation for phosphate
mine reclamation concerning streamflow characteristics and develop evaluation methods,
and changes to permitting criteria.
RESPONSIBLE PARTIES: FDEP, phosphate industries, local governments.
TENTATIVE SCHEDULE:
1. Initiate meetings with phosphate industry in 2003.
2. Interact with FDEP Bureau of Mine Reclamation to evaluate revisions to existing rules
concerning streamflow criteria.
3. Review reclamation plans as they are proposed by the mine schedule.
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EXPECTED BENEFITS: Protection of a flow regime of streams in the eastern portion of the Little
Manatee River basin.
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ISSUE #5: REVISE DIVERSION SCHEDULE FOR FLORIDA POWER AND LIGHT POWER PLANT
BACKGROUND:
The Florida Power and Light Corporation makes periodic withdrawals from the Little Manatee
River to provide make-up cooling water for their Manatee Power Generation Plant. In 1995, FP&L
submitted a site certification application to convert the power plant fuel from oil to orimulsion, an
emulsified bitumen product from Venezuela. As part of the site certification, the District
established a revised diversion schedule for the power plant that provided greater protection for
the river. The revised schedule also required the use of reclaimed water and groundwater
quantities previously permitted for other uses. The orimulsion conversion was not approved.
However, the existing diversion schedule should be revised to provide a similar level of protection
for the river.
STRATEGY:
Revise the diversion schedule for diversions from the Little Manatee River by the Florida Power
and Light Power Plant to comply with agency recommendations. Evaluate alternative revisions of
the diversion schedule.
ACTIONS:
Since Orimulsion conversion is not approved, begin negotiations with Florida Power and Light
regarding alternative revisions of the diversion schedule for the Little Manatee River.
RESPONSIBLE PARTIES: FP&L, SWFWMD
TENTATIVE SCHEDULE: Revisit the diversion schedule as part of the determination of minimum
flows for the Little Manatee River.
EXPECTED BENEFITS: Ensure protection of a flow regime of Little Manatee River while allowing
for increased electrical power generation.
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ISSUE #6: MINIMUM FLOWS FOR LITTLE MANATEE RIVER
BACKGROUND:
The District has scheduled to establish minimum flows for the Little Manatee River system, which
can include springs, tributaries, lakes, wetlands and aquifers within the watershed, in the 2006-
2015 time frame. The exact year for minimum flow determination will be determined as this time
horizon grows closer. Minimum flows are defined in the Florida Administrative Code as “the limit
at which further withdrawals would be significantly harmful to the water resources or ecology of
the area.” In evaluating minimum flows, the District will evaluate the needs of natural systems
associated with the Little Manatee River, and reductions in the flow regime of the river that will
not cause significant harm to the resources of the river.
STRATEGY:
Adopt minimum flows for the Little Manatee River to establish limits to withdrawals that will not
cause significant harm to the water resources or ecology of the area.
ACTIONS:
1. Collect and evaluate a hydrologic and ecological information necessary to establish
minimum flows for the Little Manatee River.
2. Adopt minimum flows for the Little Manatee River.
RESPONSIBLE PARTIES: SWFWMD, Environmental Protection Commission of Hillsborough
County (EPCHC), Manatee County.
TENTATIVE SCHEDULE:
1. Collect and evaluate hydrologic and ecological information necessary to establish
minimum flows for the Little Manatee River sometime between 2006 and 2015.
2. Adopt minimum flows for the Little Manatee River sometime between 2006 and 2015.
EXPECTED BENEFITS: Protection of flow regime and natural resources of the Little Manatee River.
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CHAPTER IV. FLOOD PROTECTION
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 is not without consequences. Floods have caused a greater loss of life and property,
and 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, concerns with 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:
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.”
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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
for 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. 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. Distinction 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 urbanization 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 consideration. Longterm
planning and partnerships with 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 promote these goals.
4.1 General Description of Watershed and Community
The Little Manatee River is about 40 miles long, and drains an area of approximately 222 square
miles in Hillsborough and Manatee counties. Headwaters of the Little Manatee River originate
from a swamp region located in southeastern Hillsborough County from which the river flows
westerly into Tampa Bay near Ruskin. This watershed is made up of twenty major drainage subbasins.
The basins are depicted in Atlas map 2.
The Little Manatee River’s principal tributaries are the North and South Forks which join
approximately 22 miles above the river mouth. The North Fork is primarily located within
Hillsborough County and conveys surface runoff from approximately 65 square miles. The South
Fork is primarily located within Manatee County and conveys surface runoff from an area of
approximately 40 square miles. In addition to these tributaries, Frog Creek is a major surface
water feature in the southern half of the watershed. Frog Creek is entirely within Manatee
County, and extends from Parrish to Terra Ceia Bay.
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Land surface elevations near the headwaters of the Little Manatee River reach levels around 125'
above mean sea level (NGVD). Immediately to the west, much of the drainage system crosses a
small northern lobe of the DeSoto Plain, and the lower third of the watershed lies in the Gulf
Coast Lowlands, where elevations range from seal level to 50' NGVD. The two principal
tributaries of the river are narrow and well incised. The average channel slope for the northern
tributary is 0.13% near the Fort Lonesome area. Near the United States Geological Survey (USGS)
stream gauge at Highway 301, the channel slope of the river becomes gentler and minor tidal
fluctuations are observed at the gauge during low flow periods. In its lower 10-mile reach, the
river channel and floodplain become much wider. Tidal creeks, bayous, and mangrove-dominated
islands become prevalent in this river section.
Western portions of the watershed are characterized by floodplains that are nearly level to level
and gently sloping, while higher, gently rolling areas characterize the central and eastern portions.
Lake Wimauma, situated in the central portion of the watershed, and Carlton Lake, located in the
eastern portion of the watershed, are the only natural occurring lakes within the Little Manatee
River watershed. Lake Parrish is a man-made reservoir constructed by Florida Power and Light
Corporation for power plant cooling. The cooling-water reservoir is located in the south-central
portion of the watershed about 1½ miles downstream of the confluence of the South Fork Little
Manatee River. Water is pumped from the Little Manatee River into the offstream reservoir which
is an almost 4,000 acres in size. Besides the lakes and reservoir, numerous intermittent, shallow
ponds occupy the watershed.
The runoff potential for the Little 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. About 90% of the soils have a B/D, C, or D hydrologic classification (see Atlas map 7).
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
Little 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.
The analysis showed that approximately 24 rainfall events occurred over the period meeting this
criterion. 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 Little
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 low-lying areas along and well inland of the coast.
Susceptibility is quite high since the Little 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. The population centers most susceptible to a flood situation
are the cities of Ruskin and Palmetto, situated near the coast. The susceptibility is primarily from
tidal surges resulting from hurricanes and other cyclonic disturbances. Other populated areas of
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interest are the Sun City, Sun City Center and Wimauma communities. Any flooding concerns in
these areas would be the direct result of runoff and not tidal surges. Flood-prone areas within the
watershed are depicted in Atlas map 7.
Agriculture is the predominant land use within the watershed with row crops, pasture and citrus
groves representing the major categories. Urban land uses predominate along the western
portion of the watershed, near the coast. Commercial areas can be found along the Gulf coast
and U.S. Highway 41 while industrial developments are generally located along the CSX Railroad
line. Port Manatee, situated on Manatee County’s coast, is one of the watershed’s larger
industrial areas.
According to the 1995 Land Use and Land Cover for the Little Manatee River watershed, urban and
built-up land uses occupy 15,939 acres or 12% of the total watershed area. A relatively small
portion of this land use (i.e., 2,867 acres or 1.63%) is located within Federal Emergency
Management Administration’s designated 100-year flood zone . These flood-prone areas are
subject to local and tidal flood conditions. Atlas map 9 gives the distribution of urban areas within
FEMA flood zones.
Mining activities will begin to predominant in the eastern portion of the watershed in the near
future. Approximately, eighty-thousand acres within the area have been permitted for mining.
Flooding resulting from the mining operations is of minimal concern except in the event that an
impoundment area is breached. Typically, runoff from mining areas is reduced due to the
increase storage provided as a result of the extraction.
4.2 Historic Floods of Record
As previously mentioned, some of the cyclonic storms that passed within the vicinity of the Little
Manatee River watershed produced severe floods and structural damage. A brief summary of
seven of those storms is presented (FEMA, 1989) to provide a historical perspective of the flood
hazards and depths and to draw attention to the threats posed by the phenomena. Tidal surges
caused most of the damage; however, others were the result of both surge and heavy rainfall.
September 25, 1848
This hurricane entered the western coast of Florida in the vicinity of Tampa Bay. A 14-foot
estimated tidal surge occurred within this area. A second storm also occurred on the October 12
that generated a 9-foot tidal surge.
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. Tampa Bay recorded a
maximum tide height of 9.6 feet. Substantial property damage and agricultural losses were
sustained within Hillsborough and Manatee counties as a result of the tidal surge.
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September 11-22, 1926
At the time, this was one of the most destructive storms of the century for Florida. It 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 11. Waves caused erosion along the coast.
Statewide the storm damage was estimated at $100 million.
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 Hillsborough and Manatee counties and
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 in Manatee County. Tides in Hillsborough County were approximately 5.6
feet high. The high tide in conjunction with wave action caused damage to homes, seawalls,
revetments and roads. Damage in Manatee County was estimated at $2 million.
December, 1997
From the month of December 1997 through the month of March 1998, the El Niño phenomena
created several cyclonic waves that produced 33-inches of rainfall in the Little Manatee River
watershed. Some of these rainfall events caused minor flood damage to residences in developed
areas of the watershed.
4.3 FLOOD HAZARD INFORMATION
The July 15, 1992, Revised Flood Insurance Study performed by FEMA for Manatee County and
the August 3, 1992, Revised Flood Insurance Study for Hillsborough County used information
from unpublished and published flood studies to establish water surface profiles for the tributaries
associated with the Little Manatee River watershed. Storm surge effects were also integrated into
the water surface profiles provided. Establishment of coastal flood levels was performed using the
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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-discharges
along river reaches were developed from information provided by the United States Geological
Survey gauge station data, and Dames and Moore (1975). 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.
4.4 LAND USE AND STORMWATER RUNOFF REGULATION
Prevention of flooding and other stormwater quantity problems historically has been through
enactment of land use and stormwater runoff regulations. These regulatory responsibilities
have been separated based on local, state, and federal jurisdictions. Local government has
zoning authority, applies floodplain building ordinances in conjunction with the Federal Flood
Insurance Program and specifies stormwater regulations related to their stormwater
management infrastructure.
State government, through the FDEP, regulates water quality and quantity. This authority has
been delegated to some water management districts, including SWFWMD. Each water
management district has its own variation of rules and thresholds of development size and density
applicable to permitting exemptions.
At the federal level, the Army Corp of Engineers has jurisdiction over most, if not all, navigable
water ways and certain wetlands. Typically, the Corp regulates operations such as dredge and fill
and the construction of dams and levees within “Waters of the U.S.,” which includes the Little
Manatee River. In addition, the U.S. Environmental Protection Agency regulates stormwater runoff
through National Pollutant Discharge Elimination System (NPDES) requirements. IMC’s
phosphate operation, situated in eastern portion of the watershed, is regulated by these
requirements.
4.4.1 District Regulations
Chapters 40D-4, 40D-40, 40D-400 and 40D-6, F.A.C., provide the basis of water quantity control
within the District. Much of the Little Manatee River watershed falls under the general
requirements, which specify that the post development condition peak runoff rate shall not exceed
the pre-development peak rate for a 25-year 24-hour duration design storm. In closed watersheds
(i.e., those without a surface outfall up to and including the 100-year, 24-hour event), postdevelopment
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 the Little Manatee River
watershed manifest a surface water outfall feature.
Floodplain encroachment is also regulated by the District. Regulations require that
compensating storage be provided for fill placed within the 100-year floodplain. Conveyance
restrictions resulting from new facilities crossing the floodplain, such as roads, bridges, and
pipelines are also required to have no adverse impacts to floodplain levels.
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4.4.2 Local Government Activities
The Little Manatee River watershed is within the jurisdiction of two counties (Hillsborough and
Manatee) which have standards governing the control of runoff generated from a site. 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 sub basins located
within the developing basins of the county. The ultimate goal is to maintain a natural floodway.
Encroachments into these 25-year floodplains 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. Also, the
comprehensive plan stipulates that conveyance structures within the development shall 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 provide for 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. 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 should be followed
unless the proposed system is located within a known flooding area or in a restrictive outfall
setting. If these conditions exist, then the system design criteria are more stringent. Also, facility
ownership and maintenance guidelines are provided within the manual.
County-wide, Hillsborough County requires that post-development peak discharge rates for the
25-year, 24-hour event does not exceed pre-development discharge rates for the 10-year, 24-hour
event for new developments. This regulation applies to open watersheds, a watershed with an
outfall. Hillsborough County’s open watershed regulations are more stringent than those
enforced by the Manatee County and the District.
City of Palmetto, the watershed’s only municipality, implements the District’s stormwater
regulations. In regards to stormwater management planning, a stormwater facilities plan was
completed for the City in 1998. This plan addresses the jurisdiction’s stormwater management
needs for the next 5 years.
In addition to stormwater regulations, each of the local governments regulates land use within
their boundaries in accordance with a state-approved comprehensive plan. These plans specify
the type and amount of development allowed in any given area. As a result, the plans influence
the amount and extent of development that will be allowed within the floodplains.
To participate in the National Flood Insurance Program, the FEMA specifies that participating
local governments adopt floodplain management ordinances meeting FEMA’s specifications.
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The local government then acts as FEMA’s agent for floodplain information as it pertains to the
flood insurance program. Where Flood Insurance Study information is lacking, FEMA specifies
that local participators regulate floor slab levels based on the best available information. All
local governments within the Little Manatee River watershed participate in these federal
programs.
4.5 LAND ACQUISITION PROGRAMS
Several agencies have land-acquisition programs that operate within the Little Manatee River
watershed. These programs include the Department of Environmental Protection’s Conservation
and Recreational Lands program, the District’s Save Our Rivers and Florida Forever (formerly
Preservation 2000 (P2000)) program and Hillsborough County’s Environmental Lands Acquisition
and Preservation Program. For example, riverine corridors have been purchased within the Little
Manatee River watershed for flood control, water quality and habitat protection.
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 these areas are avoided.
4.6 OTHER GOVERNMENTAL ACTIVITIES
Manatee and Hillsborough counties, and the SWFWMD have a system for tracking 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 Florida Department of
Transportation (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. Hillsborough County keeps a record of reports of yard, street and home
flooding indexed by section, township and range. The record also includes actions taken or
proposed in regard to the reported flooding.
In addition, Hillsborough County has been working on a watershed management plan for the Little
Manatee River watershed. This plan will cover flood control, water quality, natural systems, and
water supply issues related to stormwater management, and is expected to soon be completed.
The initiative’s end product will be a series of alternatives for addressing flooding and water
quality issues for consideration by local policy makers. These alternatives may include
recommendations for such things as construction of projects, changes to regulations, and needed
improvements to maintenance and monitoring programs.
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4.7 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.
4.8 GENERAL FLOOD ISSUES
Natural fluctuations of surface water elevations occur in the landscape of uplands and water
features within the watershed. 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 floodprone
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 nonstructural
surface water management methods.”
Review of existing studies, current SWFWMD activities, and discussions with county staff suggests
only minor flooding conditions exist the Little Manatee River watershed. In general, it appears that
the attenuation and conveyance capability are sufficient 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. The Level of
Service provided under the “natural setting” was properly defined which has for the most part
prevented encroachment into the existing floodplain. Encroachments into the floodplain create a
condition in which storage and/or conveyance capacity are diminished that can exacerbate a flood
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.
The following tables provide a summary of the estimated areas of existing urban uses within the
FEMA 100-year designated flood hazard zones. Existing urban land uses within the FEMA flood
zones are based on 1995 aerial photography for the Little Manatee River watershed. The existing
urban area within the 100-year flood zone is approximately 2,867. For this reason, flooding and
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continued development within the floodplain is a concern. Nevertheless, Hillsborough and
Manatee counties’ local regulations should ensure that finished floor elevations of new homes are
above the designated flood elevation.
Total area within the Little Manatee River watershed that is in the FEMA 100-year is about 20,603
acres. The total area within flood zone ‘C’ (area of minimal flooding) is 116,272 acres. However,
comparisons between wetland acreage and the amount of acreage designated as a FEMA floodprone
area suggests that the level of detail in these areas is lacking. Acreage for wetland areas is
significantly greater than the acreage of the flood zone areas which should automatically be
included within the flood zones.
Table 4.1 1995 Urban Land Use (Existing ) Within FEMA 100-Year Flood Zone
Land Use Classification
Acreage
Residential 5 Units/Acre (759.66)
Commercial and Services (240.11)
Industrial (116.89)
Extractive 557.94
Institutional 41.20
Recreational 87.05
Open Land 233.35
3,786.98 (2,867.24)
Total:
( ) represents only the acreage included in the urban classification.
4.9 SOURCES FOR STORMWATER MANAGEMENT DATA
Only a small number of flood studies have been performed within the Little Manatee River
watershed to develop flood levels and flood hazard maps. The purpose of this section is to
identify those studies and provide a brief overview of their scopes.
4.9.1 Reynolds, Smith and Hills, Architects-Engineers-Planners, Incorporated, “A Brief on Little
Manatee River 100-Year Floodplain for W-G Development Corporation,” October, 1972.
A floodplain assessment was performed for W-G Development land holdings within the Little
Manatee River watershed. The property was bounded on the east by U.S. 301, on the north by
the Little Manatee River, on the south by the Hillsborough-Manatee County line, and the west
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oundary was 4.5 miles west of U.S. 301 bridge that crosses the river. USGS stage and discharge
records for the gaging station located just downstream of the U.S. 301 bridge were used to
establish flood levels within the river. Flood levels for Tampa Bay were also included.
4.9.2 Dames and Moore, Incorporated, “Hydrobiologic Assessment of the Alafia and Little
Manatee River Basins,” June, 1975.
This study was performed to establish the baseline hydrobiologic conditions of the Alafia and Little
Manatee river watersheds. Existing baseline conditions for the ground and surface water systems
were established along with biological considerations. Surface water dynamics of the Little
Manatee River were also investigated which included the determination of the mean annual, 10-,
25-, 50-, and 100-year floodplains. The cross sectional information developed in this study was
used by FEMA in establishing their base flood levels for the watershed. The primary focus of the
study was water supply from ground and surface water sources.
Flows and levels determined from this study were based on statistical analysis of historical flows
at Wimauma and a steady-state water surface model. Flows for various return intervals were
estimated using a Log-Pearson III distribution analysis of the maximum annual series developed
from the Wimauma gaging station. These flows were then incorporated into the Army Corps of
Engineers step-backwater model (HEC-2) to develop the water surface profiles for the river.
4.9.3 Lake Level Studies, Southwest Florida Water Management District
In addition to flood studies of the Little Manatee River and its tributaries, analyses have also
included flood level determinations for Lake Wimauma and Carlton Lake. Lake flood frequency
elevations were developed in conjunction with the SWFWMD’s Lake Levels Program. This
program establishes lake level guidelines for lakes within the District, including the 10-year flood
warning level. Early in the program, staff was directed to work only on those lakes (usually 10
acres or greater in size and not wholly owned by one owner) that have control structures, water
use permits, or special problems. Levels for the two lakes in the Little Manatee River watershed
have been adopted. The objective of the program is to maintain the water resource and
environmental functions of the lakes.
Lake Levels Program reports are published annually to update the list of all lakes having adopted
levels. Another report, which includes all flood frequency elevations developed during the course
of lake level studies, Flood-Stage Frequency Relationships for Selected Lakes (1992) is also
published by the District. This report is updated approximately every five years.
4.9.4 “The 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 duration. Construction of retention/detention facilities
must increase the time of concentration of a watershed. They are to be safe and aesthetically
pleasing.
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4.9.5 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 known 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 Lake Manatee
watersheds and along the coast, an additional 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.
4.9.6 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. To address this, the study recommends that development within the Evers Reservoir
watershed preserve characteristics of both water quantity and quality. In addition, there is
indication of a slow moving groundwater flux. Base flow separation 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. In response to the findings, the study
recommends that a stormwater plan return 90% of the runoff waters to the groundwater system.
This conclusion could also be extrapolated to the Manatee River Basin. Design criteria were
specified for the ponds to meet the overall objectives.
4.9.7 USGS gauges - Flow Data
02300100 “Little Manatee River Near Fort Lonesome,” latitude and longitude (27-42-16/82-11-53),
drainage area 31.4 square miles (sq. mi.), initiated in 1963.
02300500 “Little Manatee River Near Wimauma,” latitude and longitude (27-40-15/82-21-10),
drainage area 149 sq. mi., initiated in 1939.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.12

4.10 ACTION PLAN: FLOOD PROTECTION
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 rainfall probability. The purpose of the following sections is to identify issues
associated with flood protection so that action plan strategies can be developed.
ISSUE #1: 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 are 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 data availability. 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:
1. Develop a standardized data management system that provides the information required
to define the flood-prone areas (hydrologic/hydraulic information and flood levels).
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.
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.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.13

4. Use of data management tools to update the database through the SWFWMD’s regulatory
process by requiring permit (i.e., Environmental Resource Permit (ERP)) submittals to
include data in widely accepted format and data standards.
5. Perform aerial mapping with contour information (paper and digital formats) for areas in
the watershed that have no such information or outdated information.
6. Promote cooperative agreements to build data collection responsibilities based on need
and the capabilities of the agency (FEMA, SWFWMD, counties, cities, private, etc.).
RESPONSIBLE PARTIES: FEMA, SWFWMD, FDEP, local governments and modeling vendors.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Increased access to flood data.
The following are major District projects addressing this issue.
Project: Hillsborough County & City of Tampa One Foot Contour Aerial Mapping.
This project, which is part of the ongoing cooperative effort between the Board and Hillsborough
County, serves as part of the Stormwater Management Program. The one foot contour mapping
from aerial photography project will help to determine the effects of developments in the area on
the natural drainage of the area. In addition, the 1929 Vertical Datum is being updated to
NAVD88, changing elevations by approximately one foot. New survey marks will be set and new
contours will assure accuracy. The measurable benefits include adding contours to the County’s
contour map, updating the GIS System Base Map, warning citizenry of flooding dangers, assisting
the District in floodplain identification and assisting Emergency Operations Centers in shelter
locations for emergency planning.
Participants: Hillsborough County, City of Tampa and the Alafia River, Hillsborough River and
Northwest Hillsborough Basin Boards.
Status: Ongoing.
Project: Mapping and Geographic Information System.
This initiative is to provide Geographic Information System, aerial photo interpretation and
photogrammetric mapping services to District activities. GIS support includes the input,
management, analysis and distribution of spatial data, the design and implementation of
databases, software training and map production. Aerial photo interpretation includes land
use/cover mapping in support of land acquisition, the Surface Water Improvement and
Management program, engineering, planning and environmental studies. Photogrammetric
support includes the mapping of one foot contours, collection of aerial photographs and satellite
imagery and the production of digital orthophotography.
Participants: District and all Basin Boards.
Status: Ongoing.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.14

Project: Orthophoto and Land Use/Cover Mapping.
In 1988 the District began its Geographic Information System (GIS) data collection effort. The
foundation of this effort has been the collection of the following data layers: 1) Orthophotos.
These computerized images created from color infrared aerial photographs. The photographs are
taken by specialized cameras from aircraft flying at an altitude of 20,000 feet. The photographs
are scanned and registered to a ground based mapping coordinate system, and can therefore be
used in conjunction with standard surveying information and other GIS data. The location of
features such as buildings can be measured to accuracies of approximately 20 feet on these
orthophotos. 2) Land Use/Cover. Trained interpreters use the aerial photographs and
orthophotos to map more than 30 different categories of land use/cover. Examples of these
categories include pine forests, lakes, single family residential and row crops. The orthophotos
and land use/cover layers serve as the base maps for most GIS layers.
Participants: District and all Basin Boards.
Status: Ongoing.
Project: United States Geological Survey, Alafia River Basin Surface Water Flow, Level, and Water
Quality Data Collection.
This initiative is to establish and maintain the Alafia River Basin’s surface water monitoring, and is
jointly funded by the Alafia River Basin and the United States Geological Survey. It provides basic
data collection to support assessing flood events, developing surface water management plans,
facilitating habitat restoration projects, establishment and monitoring of minimum flows and
levels, land acquisition and management and other critical water management activities. Surface
water stage and/or discharge is measured at twelve sites. Water quality is monitored at five sites.
In FY 02, three continuous surface water gauging stations will be added. In FY 03, recording
instrumentation on the South Prong of the Alafia River will be upgraded to provide real-time data.
Participants: Alafia River Basin Board.
Status: Ongoing.
Project: United States Geological Survey, Manasota Basin Surface Water Flow, Level, and Water
Quality Data Collection.
This initiative is to establish and maintain the Manasota Basin’s surface water monitoring, and is
jointly funded by the Manasota Basin and the United States Geological Survey. It provides basic
data collection to support assessing flood events, developing surface water management plans,
facilitating habitat restoration projects, establishment and monitoring of minimum flows and
levels, land acquisition and management and other critical water management activities. Surface
water stage and/or discharge is monitored at eleven sites. Water quality is monitored at five sites.
In FY 02, seven continuous surface water gauging stations will be added. In FY 03, three tidal
stage/water quality gauging stations will be added and two stage/discharge gauging stations will be
added in the basin in support of establishment of minimum flows and levels.
Participants: Manasota Basin Board.
Status: Ongoing.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.15

ISSUE #2: COLLATING 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 Little Manatee River
watershed 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.
In addition, associated hydrologic/hydraulic information should be processed and incorporated
into the database.
STRATEGY:
Develop a GIS database of current floodplain information for the Little 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: FEMA, SWFWMD, FDEP and local governments.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Increased access to flood data.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.16

ISSUE #3: 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 of the watershed, based upon physical data and assumptions
of the watershed characteristics. The amount and quality of data used for input determine 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 sufficient 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 cities and
counties in the watershed for distribution to contractors when hiring outside consultants
to perform flood and stormwater management studies.
RESPONSIBLE PARTIES: FEMA, SWFWMD, FDEP, local governments and modeling vendors.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Improved flood-prone area analysis.
The following are major District projects addressing this issue.
Project: Hillsborough County Surface Water Modeling Coordination.
Hillsborough County has recently complete watershed models for seventeen basins within the
county. These models are being used by the county as the best available data. Developers are
also interested in fully utilizing the model. Prior to the full integration of these models into
regulatory and other initiatives, the District needs to perform a review of these models. Funds
budged for the effort will be used to hire consultants to facilitate this process.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.17

Participants: District and Alafia River, Hillsborough River and Northwest Hillsborough Basin
Boards.
Status: Proposed.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.18

ISSUE #4: 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 as a watershed is developed. To counter these
effects, the SWFWMD, and Hillsborough and Manatee counties have dictated that the post
development peak runoff rates can be no greater than the pre-development runoff rates. In the
case of Hillsborough, the post 25-year peak discharge cannot be greater than the pre 10-year peak
runoff. 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 regulations
require a similar analysis, known as the "critical event" analysis. 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. Use of storm water for irrigation purposes is
potentially another method for reducing runoff volumes. If scaled properly, the volume available
in stormwater holding ponds could also provide some 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.
RESPONSIBLE PARTIES: FEMA, SWFWMD, FDEP, local governments and developers.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.19

TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Minimized impacts due to peak flow situations.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.20

ISSUE #5: 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 areas were not properly illustrated on Flood
Insurance Rate Maps (FIRM) administered by the Federal Emergency Management Agency.
Storage of floodwaters occurs on most properties in Florida, especially where jurisdictional
wetlands exist. Regulations, now enforced by the District and county governments, require that
storage in these areas be included in the existing condition analysis (pre-development) 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. Not all land use alterations are regulated, which provide 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 require an Environment Resource
Permit. Diversions, fill, and restrictions can be constructed within the floodplain that alter its
function. Development of a sufficient infrastructure inventory and identification of the floodplains
can help prevent this.
Flood levels for the Little Manatee River watershed are based on a distributional analysis of flows
and the step-backwater model HEC-2. A Log-Pearson III frequency analysis of existing gauge
information was used to estimate peak discharges while a relational formula was used to calculate
peak discharges based on contributing area. HEC-2 model was then used to predict the resultant
water surface elevations along the conveyance ways. This approach to establishing flood levels is
ballpark at best and therefore may tend to have large predictive errors. These predictions could
result from undetermined hydraulic features of the basin, incomplete knowledge of the rainfall
volumes and distributions, and varying antecedent moisture conditions.
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 there associated infrastructure.
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 available when needed, i.e.,
concurrent 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.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.21

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.
RESPONSIBLE PARTIES: FEMA, SWFWMD, FDEP, local governments and developers.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Improved flood data.
The following is a major District projects addressing this issue.
Project: Hillsborough County Surface Water Modeling Coordination.
Hillsborough County has recently complete watershed models for seventeen basins within the
county. These models are being used by the county as the best available data. Developers are
also interested in fully utilizing the model. Prior to the full integration of these models into
regulatory and other initiatives, the District needs to perform a review of these models. Funds
budged for the effort will be used to hire consultants to facilitate this process.
Participants: District and Alafia River, Hillsborough River and Northwest Hillsborough Basin
Boards.
Status: Proposed.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.22

ISSUE #6: USE OF SURFACE WATER SYSTEMS FOR WATER SUPPLY AND FLOOD CONTROL
BACKGROUND:
Water supply is a critical concern in the Manatee County area. For example, the Evers Reservoir
has been expanded to provide additional water for the City of Bradenton, while the county is
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 into 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. Hillsborough County’s policies regarding reuse of surface water are
unknown.
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 Hillsborough and Manatee counties and municipalities within the watershed. Water
supply storage should be considered in conjunction with the storage necessary for flood
control. 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: SWFWMD, FDEP, local governments and developers.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Increase development and use of dual use flood ponds.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.23

ISSUE #7: 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 factor 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 estimated 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.
STRATEGY:
Statistical comparisons should be made between the design percent imperviousness and the
actual constructed imperviousness.
ACTIONS:
1. Random sampling of lots from existing developments should be made from field
observations (tax assessor information) 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 originally 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 with study
results.
RESPONSIBLE PARTIES: SWFWMD, FDEP, local governments and developers.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Increased accuracy of flood information.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.24

ISSUE #8: USE OF BASIN-SPECIFIC CRITERIA TO ADDRESS UNIQUE CIRCUMSTANCES
BACKGROUND:
Establishment of basin-specific criteria should aid in addressing unique conditions within the
surface water system, thereby improving management decisions. For example, in the Braden
River watershed, recommendations were made by Wanielista (1989) 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. Basinspecific
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. Also 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.
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 areas.
3. Encourage alternatives to impervious surfaces such as porous pavement. Benefits should
be presented and incentives provided.
RESPONSIBLE PARTIES: SWFWMD, FDEP and local governments.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Implementation of basin-specific criteria to address unique circumstances.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.25

ISSUE #9: 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 encroachments are greater than permitted. With respect to data
collection and analysis, there is a need for additional monitoring of surface water elevations to
determine changes over time. Currently, water elevations are being monitored at only two sites.
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.
3. Perform periodic inventories to document land use changes within the watershed. The
information should be developed on a GIS platform.
RESPONSIBLE PARTIES: USGS, SWFWMD, FDEP and local governments.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Increased availability and reliability of flood data.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.26

ISSUE #10: CONFLICTS WITH LAND USE PLANNING AND WATER MANAGEMENT
BACKGROUND:
Current land use regulations within Hillsborough and Manatee counties 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 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 to maintain primary conveyance ways. However, this
has been limited to basins along the coast and within the Manatee River watershed area. 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 attenuation. 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 a costly detention/diversion system. Purchase of homes is an option
that is sometimes difficult to implement due to the high cost of the structures and the lack of
willing sellers.
The home rule authority of local governments 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. Hillsborough and Manatee counties are actively involved in this
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.
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.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.27

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 to
reduce premiums.
6. Determine and establish appropriate setbacks from riparian systems for any structure, i.e.,
landward of 100 year floodplain, or some distance from 10 year floodplain or wetland
boundary. State agencies need to work with local governments to enforce setbacks.
7. Lobby local governments to change land use plans to limit densities in floodplains. A
question is raised regarding acceptable densities.
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: FEMA, SWFWMD, FDEP and local governments.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Reduced development within flood-prone areas.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.28

ISSUE #11: RAINFALL FREQUENCY AND DURATION ANALYSIS
BACKGROUND:
Flooding in Hillsborough and Manatee counties may result from 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. To the south of Manatee County, in Sarasota
County, the design storm has been increased from the 25-year pre- and post- to a 100-year preand
post- for peak discharge predictions because of repetitive flooding in the 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 Little Manatee River
watershed.
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.
RESPONSIBLE PARTIES: SWFWMD, FDEP and local governments.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Increased accuracy of flood data. Reduced flooding.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.29

ISSUE #12: 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 crosssectional
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, drainage district and authorities, State, local
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
Little Manatee River watershed. This includes developing the strategies for maintaining
and operating the systems, obtaining easements or ingress and egress agreements with
property owners, and identifying the governments or other responsible parties to complete
the work.
RESPONSIBLE PARTIES: SWFWMD, FDEP, local governments, drainage authorities and districts.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Improved maintenance and operation of flood systems.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.30

ISSUE #13: 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.
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.
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 Little 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 for depth of flooding etc.).
RESPONSIBLE PARTIES: SWFWMD, FDEP, local governments and developers.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Development of more environmentally friendly stormwater systems.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.31

ISSUE #14: FUNDING SOURCES FOR FLOOD MANAGEMENT PROGRAMS
BACKGROUND:
Funding mechanisms are available for surface water management 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 hazard mitigation
and special projects fall into this category. Local 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 watershed master planning process 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 management 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 other 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 should 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 management utility fees from the entities that
are beneficiaries of the system.
3. Encourage the establishment of special assessment districts.
4. Encourage contributions to regional facilities that are based on a Stormwater Management
Master Plan.
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
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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 are funded with disaster mitigation funds.
RESPONSIBLE PARTIES: SWFWMD, FDEP, local governments and developers.
TENTATIVE SCHEDULE: Undetermined.
EXPECTED BENEFITS: Improved design of stormwater projects.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.33

ISSUE #15: 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 be frequently inundated during storm events.
2. Educate the public on the hydrologic cycle and its interaction with the water resource and
effects on water use.
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.
RESPONSIBLE PARTIES: SWFWMD, FDEP, FEMA and local governments.
TENTATIVE SCHEDULE: Undetermined
EXPECTED BENEFITS: More informed public on flood protection issues.
LITTLE MANATEE RIVER CWM PLAN
JUNE, 2002 4.34

CHAPTER V. WATER QUALITY
INTRODUCTION
Water quality in both ground and surface waters in the area of the Little Manatee River watershed
is characterized by distinct spatial gradients. The quality of surface waters differs markedly within
the basin, and the groundwater quality varies with depth from the land surface and distance from
Tampa Bay. In many areas the quality of both ground and surface waters have changed over time,
due largely to increased groundwater use and associated land uses. This chapter summarizes the
water quality characteristics of both ground and surface waters in the area extending from the
Little Manatee River south to Terra Ceia Bay, describes special regulatory and management criteria
that apply within the region, and discusses current management issues relevant to the water
quality of these resources.
5.1 GROUNDWATER QUALITY
Groundwater quality is affected by the quality of the recharge waters, the porous media through
which the water flows, and the duration of contact with the porous media (Brown, 1983). In the
Little Manatee River watershed, groundwater quality may also be affected by mixing with seawater
or mineralized waters from lower depths.
5.1.1 Surficial Aquifer
The surficial aquifer consists primarily of unconsolidated fine-grained sand deposits which vary in
thickness from 0 to greater than 50 feet (Wolansky, 1979). In the Little Manatee River watershed,
the surficial aquifer is used to a limited extent for residential irrigation and livestock watering.
Generally, the quality of the water is good except in the tidally influenced areas along the coast
(Brown, 1983). Water quality in the surficial aquifer is affected by precipitation, agricultural
practices, septic systems, discharge from the Floridan aquifer, and the location of the
freshwater/saltwater interface. Table 5-1 presents water-quality data for three surficial aquifer
wells (wells 1, 2 and 3) located in or near the Little Manatee River watershed. Well 1 is closest
coastal well with surficial aquifer water-quality data. Figure 5-1 gives locations for these wells.
The ionic content, a measure of the quantity of materials dissolved in water, is high in the surficial
aquifer along the coast of Hillsborough and Manatee counties. High total dissolved solids (TDS),
chloride, and sulfate in the Little Manatee River watershed are due to mixing with seawater and
the upward leakage of mineralized waters through fractures in the Floridan aquifer. Within five
miles of the coast, TDS levels in the surficial aquifer generally range from 250 milligrams per liter
(mg/L) to 500 mg/L (Aquifer Groundwater Quality Monitoring Program (AGWQMP), 1990) (Florida
Department of Environmental Protection’s drinking water standard for TDS is 500 mg/L.). As
indicated in Table 5-1, an elevated TDS value of 486 mg/L was measured at well 1, located in
southern coastal Hillsborough County. The high TDS and sulfate levels observed in this surficial
well may be indicative of seawater intrusion. The infiltration of urban and agricultural runoff, may
LITTLE MANATEE RIVER CWM PLAN
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Figure 5-1 Groundwater Quality Monitoring Wells
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Table 5.1 Water Quality in Selected Surficial Aquifer Wells
Physical Parameters Well 1 Well 2 Well 3 Potable Standard 4
pH, laboratory 7.1 6.7 5.0 >6.5
Temperature, C 24.0 25.0 27.5 n/s
Specific Conductance,
(µmhos/cm)
Total Hardness (mg/L) as
CaCO 3 )
950.0 400.0 45.0 n/s
369.0 206.0 3.0 n/s
Major Ions (mg/L)
Dissolved Solids (calculated) 1 486.0 294.0 51.0 500.0
Bicarbonate 2 (mg/L as CaCO 3 ) 190.0 52.0 0.74 n/s
Calcium 130.0 49.0 0.29 n/s
Carbonate 2

also contribute to high TDS in the surficial aquifer. The location of the saltwater front in the Little
Manatee River migrates in response to tidal and streamflow fluctuations and can be found at
significant distances inland (AGWQMP, 1990). In this portion of the Little Manatee River
watershed, the ionic content of the surficial aquifer is low, with TDS content generally less than
300 mg/L (AGWQMP, 1990). Water from wells 2 and 3, located in the eastern portion of the
watershed, exhibits TDS levels between 51 mg/L and 294 mg/L.
Iron levels in the surficial aquifer may approach or exceed the drinking water standard of 0.3 mg/L.
Elevated iron levels (well 1) result from the natural abundance of iron in sediments, organic
material, and rainfall. High iron levels in surficial aquifer wells may also result from ironproducing
bacteria.
Nitrate levels are frequently higher in the surficial aquifer than in the upper Floridan aquifer.
However, it was not possible to confirm this generalization for the Little Manatee River watershed
due to the limited amount of surficial aquifer water quality data. Elevated nitrate levels in the
surficial aquifer result from the application of nitrate fertilizers in agricultural areas and the
presence of septic systems and leaking underground sewage pipes (AGWQMP, 1990). High
nitrate levels may also be associated with cattle operations.
5.1.2 Intermediate Aquifer
The ionic content of water in the intermediate aquifer is generally higher than that of the surficial
aquifer ground water. This is because groundwater residence times in the intermediate aquifer
are longer than in the surficial aquifer. In addition, the clay, marl, limestone, and phosporite
deposits that comprise the intermediate aquifer are more soluble and contribute ions to solution
much more readily than the quartz-rich sediments of the surficial aquifer (SWFWMD, 1991).
Intermediate ground water is potable throughout most of the area. Only the coastal well 1
exceeds drinking water standards for sulfate and TDS in the watershed. Ionic concentrations
steadily decrease inland from Tampa Bay and reach a minimum in the central watershed.
Concentrations begin to increase in the southeastern part of the watershed. This can possibly be
attributed to phosphate mining activities. Rutledge (1987) notes that contamination of deeper
aquifers can be accelerated by breaching of the confining layer caused by mining or inter-aquifer
connector wells.
Table 5-2 presents water quality data for three surficial aquifer wells (wells 1,2 and 3) located in
the Little Manatee River watershed. Well 1 is located is the closest coastal well with intermediate
aquifer water-quality data. These wells are depicted in Figure 5-1.
High total dissolved solids, chloride, and sulfate in the Little Manatee River watershed are due to
mixing with seawater and the upward leakage of mineralized waters through fractures in the
Floridan aquifer. Within five miles of the coast, TDS levels in the intermediate aquifer generally
range from 250 mg/L to 600 mg/L (AGWQMP, 1990). As indicated in Table 5-2, an elevated TDS
value of 658 mg/L was measured at well 1, located in southern coastal Hillsborough
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Table 5.2 Water Quality in Selected Intermediate Aquifer Wells
Physical Parameters Well 1 Well 2 Well 3 Potable
Standard 4
pH, laboratory 7.9 7.6 8.2 >6.5
Specific Conductance,
(µmhos/cm)
876.0 738.0 289.0 n/s
Total Hardness (mg/L as CaCO 3 ) 414.0 268.0 131.0 n/s
Major Ions (mg/L)
Dissolved Solids (calculated) 1 658.0 217.0 156.0 500.00
Bicarbonate 2 (mg/L as CaCO 3 ) 161.0 161.0 140.0 n/s
Calcium 95.8 59.2 29.4 n/s
Carbonate 2 0.007 0.004 0.014 n/s
Chloride 17.9 18.9 2.27 250.00
Fluoride 0.83 0.93 0.65 4.00
Iron 0.48 0.056

in sediments, organic material, and rainfall. High iron levels in surficial aquifer wells may also
result from iron-producing bacteria.
5.1.3 Upper Floridan Aquifer
Throughout the Little Manatee River watershed, the surficial aquifer is separated from the upper
Floridan aquifer by the intermediate aquifer system‘s semi-confining units. The thickness of the
semi-confining units average about 250 feet (SWFWMD, 1993). The semi-confining unit is as
thick as 300 feet. The underlying upper Floridan aquifer is a continuous series of carbonate units
consisting of limestone and dolomite. Due to contact with soluble limestone and evaporites,
groundwater from the upper Floridan aquifer usually contains greater mineral content and
hardness than groundwater in the surficial aquifer. Water quality will vary as a function of
residence time in the aquifer, with longer residence times generally resulting in greater mineral
content. Table 5-2 presents water quality data for three upper Floridan aquifer wells located in the
Little Manatee River watershed. Figure 5-1 depicts locations for the groundwater wells conducting
the monitoring.
Groundwater from well 1, located in the coastal portion of the watershed exhibits high sulfate and
TDS values (Table 5-3). Proximity to the coastal saltwater interface results in higher mineral and
TDS concentrations. Wells 2 and 3 exhibit water quality characteristic of inland ground water.
5.1.4 Areas Susceptible to Groundwater Contamination
The US Environmental Protection Agency’s DRASTIC methodology has been applied to all five
water management districts to identify areas susceptible to groundwater contamination. The
DRASTIC methodology was developed to evaluate the groundwater pollution potential of any
hydrogeologic setting, greater than 100 acres in size, with existing information (SWFWMD, 1988).
The seven parameters used to evaluate the DRASTIC pollution potential are: (1) Depth to Water,
(2) Net Recharge, (3) Aquifer Media, (4) Soil Media, (5) Topography, (6) Impact of the Vadose
Zone, and (7) Hydraulic Conductivity. The end product of the DRASTIC methodology is a map
depicting color-coded areas of groundwater pollution potential. Each area is assigned a pollution
index which ranges from 23 (lowest pollution potential) to 230 (highest pollution potential). For a
detailed discussion of the DRASTIC methodology, the reader is referred to U.S. Environmental
Protection Agency/600/2-85/018, May 1985.
The DRASTIC methodology was developed to be applied universally, and as such, may provide
misleading results for certain hydrogeologic systems. Swancar and Hutchinson (1992) found that
the DRASTIC indices do not agree with the results of groundwater chemistry analyses in the
northern part of the SWFWMD. Within the Little Manatee River basin, the DRASTIC index
generally shows the potential for contamination to the Floridan and intermediate aquifers to be
very low, and a high potential for contamination to the surficial aquifer.
The potential for groundwater contamination in wetland areas is a function of the level of
connection between the wetland and underlying aquifers. In the Little Manatee River watershed,
Lake Wimauma may be well-connected through sinkhole-related formations to the intermediate
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Table 5.3. Water Quality in Selected Upper Floridan Aquifer Wells
Physical Parameters Well 1 Well 2 Well 3 Potable
Standard 4
pH, laboratory 7.4 8.0 8.1 >6.5
Temperature, C 26.0 26.0 n/d n/s
Specific Conductance,
(µmhos/cm)
1050.0 500.0 n/d n/s
Total Hardness (mg/L as CaCO 3 ) 434.0 207.0 196.0 n/s
Major Ions (mg/L)
Dissolved Solids (calculated) 1 792.0 375.0 207.0 500.00
Bicarbonate 2 (mg/L as CaCO 3 ) 126.0 130.0 165.0 n/s
Calcium 92.8 50.1 46.6 n/s
Carbonate 2

aquifer. Wetlands due to sinkholes are not known in the Little Manatee watershed. There is very
little recharge in the area and most of the rainfall occurring in the area flows across the ground
surface as runoff rather than recharging the aquifer.
Although discharge areas and areas with little recharge have a lower groundwater contamination
potential, any change in the head gradient can alter this susceptibility. Areas of large groundwater
withdrawals, which were naturally discharge areas or had little recharge prior to pumpage, may
become recharge areas due to lowered heads in the aquifers. This concept is referred to as
induced recharge.
The Little Manatee River watershed is an area of induced recharge due to intense agricultural
pumping demands. Groundwater withdrawals from the upper Floridan aquifer have lowered the
potentiometric surface and intermediate aquifer, creating an induced recharge area. When an
aquifer changes from discharging to recharging conditions, the potential for groundwater
contamination increases. The degree of groundwater contamination potential in areas of induced
recharge depends on both hydrogeologic properties and the rate of groundwater withdrawal, and
therefore can be variable over time.
DRASTIC indices and other hydrogeologic indicators are measures of susceptibility to
groundwater contamination and are independent of the presence of actual pollutant sources. A
high pollution potential does not indicate that groundwater contamination will occur, only that
contamination could occur if pollutant sources were present. Potential pollutant sources in the
Little Manatee River watershed include landfills, borrow pits, mining activities, stormwater ponds,
septic systems, and urban and agricultural runoff. Groundwater may also be contaminated
through the inadvertent release or spill of industrial or agricultural chemicals or waste products. A
detailed discussion of the potential for groundwater contamination from man-made byproducts in
the Tampa Bay area is presented by SWFWMD (1995).
5.2 SURFACE WATER QUALITY
Surface water quality in the Little Manatee River and adjacent coastal waters (Cockroach and Terra
Ceia bays) has received considerable study in recent years. Much of this attention has been due
to the high natural resource value of these waterbodies. Estevez et al. (1991) suggested that the
Little Manatee River was in the best hydrobiological condition of all the tributaries flowing to
Tampa Bay. In fact, several years earlier, in 1982, approximately two-thirds of the Little Manatee
River’s channel was designated as an Outstanding Florida Water (OFW). The OFW designation
extends from the Highway 674 bridge near Ft. Lonesome to the mouth of the river, including
Hayes, Miller, and Bolster bayous which are joined to the tidal reaches of the river. The regulatory
significance of the OFW designation is described in section 5.4.2 of this report.
The Cockroach Bay Aquatic Preserve (CBAP) was established in 1976, initially consisting of
submerged lands associated with Cockroach Bay and Little Cockroach Bay. These shallow bays
are formed by a series of small, mangrove dominated islands and inlets that extend south from the
mouth of the Little Manatee River along the eastern shore of Tampa Bay. In 1990, the boundaries
of the Cockroach Bay Aquatic Preserve were extended upstream in the main channel of the Little
Manatee River to the US 301 bridge, located 15 miles above the river mouth. The Terra Ceia Bay
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Aquatic Preserve was formed in 1983 to include predominantly tidal waters of all tributaries,
including Frog Creek/Terra Ceia River, McMullen Creek and the Little Redfish Creek.
The water quality and ecological health of Little Manatee River and the Cockroach Bay and Terra
Ceia aquatic preserves are closely related to the quantity and quality of freshwater inflow they
receive from their watersheds. Although these waterbodies are currently in good ecological
condition, the quality of freshwater inflows from the Little Manatee River has undergone
significant changes in recent decades (Flannery et al., 1991). In addition, land uses in portions of
the Little Manatee watershed are projected to change, as phosphate mining and urbanization are
expected to increase within the basin.
The water quality characteristics of the Little Manatee River and Cockroach Bay and Terra Ceia Bay
aquatic preserves are summarized in the following sections. Historical trends are discussed along
with recent data. Issues related to water quality in these water bodies are identified and strategies
to address these issues are discussed.
5.2.1 Freshwater
Water quality in the freshwater reaches of the Little Manatee River has been examined by several
investigators (Dames and Moore, 1975, Flannery et al. 1991; Dames and Moore, 1991; Lewis
Environmental, 1998; PBSJ, 2001). For the most part, these assessments have focused on reaches
of the river extending upstream from the long-term USGS streamflow gauging station at the Little
Manatee River near Wimauma, located at the US Highway 301 bridge. The first major study of the
Little Manatee watershed was conducted by the Dames and Moore (1975) in a report prepared for
the Alafia River Basin Board. This report provided a broad comprehensive assessment of both the
Alafia and Little Manatee rivers’ basins including their hydrology, water quality and the ecological
characteristics of both terrestrial and aquatic systems. However, much of the water quality
discussion focused on the Alafia River, due to its more intensive land use and documented
problems associated with industrial pollution.
The District performed a watershed assessment of the Little Manatee River in the late 1980s that
included extensive collection of streamflow and water quality data (Flannery et al. 1991; Dames
and Moore 1991). Water quality data analyzed in that study were available from three sources:
(1) long-term data at two sites available from the USGS; (2) data collected since the 1970s at four
sites by the Environmental Protection Commission of Hillsborough County; (3) and seven
freshwater sites monitored during 1988 and 1989 by the District. A large suite of parameters was
analyzed by the District, including major ions (e.g., sulfate, chloride), suspended materials and
nutrients. The study also assesses streamflow trends in the basin and relationships between
streamflow rates and water quality characteristics.
The District study found that water quality trends in the basin were closely related to agricultural
land use. Significant increasing trends were observed for specific conductance, sulfate, pH,
turbidity and nitrate-nitrite nitrogen at the long-term USGS station at Highway 301, a site that is
also monitored by the EPCHC. Time-series plots showed that concentrations of these parameters
began increasing in the late-1960s to mid-1970s. The trends in specific conductance and sulfate
were attributed to the effects of increasing groundwater use in the basin. Groundwaters are more
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mineralized than surface waters in the Little Manatee watershed, and analyses of streamflow
records indicated that streamflow in the basin is being supplemented by groundwaters that
originated as agricultural withdrawals from wells (Flannery et al., 1991). Waters in excess of crop
needs were enter the streams as direct runoff, or as groundwater interflow from the surficial
aquifer. Supplementation of the surficial aquifer with irrigations waters can also result in saturated
soil conditions and greater runoff after rainfall events. Mineralized water can also enter the upper
reaches of the Little Manatee from the NPDES point source discharge from the Four Corners
phosphate mine.
Increasing trends for specific conductance, pH, turbidity and sulfate were also observed at the
USGS Little Manatee River near Ft. Lonesome site (located at State Road 674), which is also
monitored by the EPCHC. The rates of increase at the Ft. Lonesome site, however, were not
nearly as pronounced as at the Highway 301 site, indicating that considerable enrichment of the
river occurs between these two locations. In general, trend analyses and time-series plots
indicated that since the 1970s the Little Manatee River has been changing from a stream with low
nutrient and mineral concentrations to a stream that is more enriched in nutrients and major ions
(Flannery et al. 1991, Dames and Moore, 1991).
In addition to long-term trends, the District study included comparisons of synoptic data collected
from seven sub-basins during 1988 and 1989. Patterns observed in the long-term trend analyses
were supported by the sub-basin comparisons. Sub-basins with the most extensive agricultural
land use tended to have concentrations of specific conductance, sulfate, particulate nutrients, and
nitrate-nitrite nitrogen that were significantly greater than sub-basins with less intensive land use.
The highest nitrate-nitrite and specific conductance values were observed in north-central portions
of the watershed where agriculture is most extensive (Dug Creek, Carlton Branch, North Fork).
Water quality in the headwaters of the river (above State Road 674) and the South Fork was the
least impacted in the watershed. This corresponded to higher percentages of land in native land
covers and pasture/range in these sub-basins instead of citrus and row crops. A point source
discharge from the IMC-Agrico Four Corners mine discharges to the headwaters of the river, but
this permitted discharge did not flow much during the District study due to slow activity at the
mine. However, phosphate mining has increased in the Little Manatee River watershed since the
District study was performed and is scheduled to increase significantly in the coming years.
Records for flows and water quality measurements for this permitted discharge are available from
the Florida Department of Environmental Protection office in Tampa.
Streamflow was also measured at the sites monitored during the District study, thus allowing the
calculation of nutrient fluxes from the respective sub-basins. Flux rates (kilograms per hectare per
year) of dissolved inorganic nitrogen (DIN) differed by an order of magnitude between the least
and most impacted sub-basins in the watershed. Flux rates for DIN differed by even greater
amounts during the dry season when flows were supplemented with agricultural irrigation waters.
For the most part, flux rates for phosphorus were relatively similar among the sub-basins
reflecting the naturally high phosphorus concentrations that occur within the Little Manatee River
basin. However, phosphorus concentrations and flux rates were less in northwestern portions of
the watershed drained by Dug and Cypress Creeks, due presumably to less phosphatic soils in
those regions.
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A subsequent study by Lewis Environmental Services, Inc. (1998) revisited trends for many of the
parameters that had been reported by the District (Flannery et al, 1991; Dames and Moore, 1991).
The purpose of this latter study was to determine if water quality in the Little Manatee River was
continuing to change, possibly causing a violation of state water quality standards in the reach of
the river that is an Outstanding Florida Water. Data from the period 1981-1982 was used as a
baseline to assess possible violations, since this was when the OFW status was first established.
To assess trends since that time, the authors relied on data collected at four stations by the
EPCHC. The one parameter that show a continued increasing trend was sulfate at Station 140,
located on the main stem of the river just above the confluence with the South Fork. This was the
same station (North Fork) where the previous District study found evidence of substantial
agricultural runoff to the river (Flannery et al., 1991).
Another assessment of water quality in the Little Manatee River and Cockroach Bay was presented
in a Cockroach Bay Aquatic Preserve Management Plan published by Post Buckley Schuh &
Jernigan (PBS&J)(1999). This extensive study was prepared for the Tampa Port Authority, the
Southwest Florida Water Management District, and the Cockroach Bay Aquatic Preserve
Management Advisory Team which serves as an advisory group to the Hillsborough County
Commission. Because a portion of the Little Manatee River is within the Cockroach Bay Aquatic
Preserve and freshwater flow from the watershed affects the ecology of the preserve, this study
examined factors affecting water quality throughout the Little Manatee River and Cockroach Bay
watersheds. The report described the distribution of septic tanks and point source discharges in
the watersheds. Using a nutrient loading model described in Zarbock et al (1996), the report
estimated loadings of total nitrogen (tons per year) from point and non-point sources in the subbasins
identified by Flannery et al. (1991) plus Cockroach Bay. The PBS&J study found that nonpoint
sources (stormwater runoff) contributed 85% of the total nitrogen load to these waterbodies.
The PBS&J report found the highest loadings of total nitrogen originated in the North Fork subbasin
of the Little Manatee River where agricultural land use is most extensive.
The PBS&J report also identified water quality issues of concern and presented action plans to
address these issues for both the Little Manatee River and Cockroach Bay watersheds.
Recommended plans included the following actions: implement the Tampa Bay National Estuary
Program’s (renamed Tampa Bay Estuary Program) Action Plans for water quality; enforce
Outstanding Florida Water standards for the aquatic preserve; encourage best management plans
for agricultural operations; encourage best management practices for industry; and encourage
best management plans for residential and recreational activities.
The most recent assessment of surface water quality in the Little Manatee River basin is presented
in a draft Little Manatee River Watershed Plan prepared for Hillsborough County by PBS&J (2001).
This report largely relies on data collected at five stations in the Little Manatee River and
Cockroach Bay by the EPCHC. Three of these stations are freshwater. Time-series plots and trend
analyses were performed on a number of water quality parameters including specific conductance,
total suspended solids, BOD, dissolved oxygen, and total nitrogen and total phosphorus. The
period of record analyzed for most of these stations ranged from the mid-1970s to 1998. The
trends evaluated by PBS&J did not indicate increasing nutrient concentrations in the watershed, as
declining trends were reported for total nitrogen, total phosphorus, and total suspended solids at
various stations. It should be noted, however, that PBS&J did not evaluate trends for nitrate
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nitrogen, which can be a meaningful indicator of agricultural runoff and for which Flannery et al.
(1992) reported enrichment in the Little Manatee River watershed. The study by PBS&J also did
not evaluate data from the long-term USGS sites in the river, which covers a longer period of
record. Nonetheless, the lack of significant increasing trends in the freshwater reaches of the river
reported by PBS&J may indicate that water quality has not continued to degrade in recent years.
However, any conclusions in this regard should be supported by further analyses that examine all
available data for a wider array of variables, including nitrate-nitrite and selected major ions.
Post Buckley also calculated Water Quality Index (WQI) values for freshwater sites within in the
basin based on the formulae provided by the Florida Department of Environmental Protection.
The WQI values are the arithmetic averages of indices calculated from six separate categories
which correspond to percentile distributions of stream water quality values within the state. To
correspond with the US Environmental Protection Agency’s National Profiles Water Quality Index,
qualitative categories of good, fair, or poor are given to ranges of values of the WQI. The Florida
Water Quality Assessment 305(b) Report published by the FDEP (Hand et al. 1996) contains water
quality data for Florida streams in terms of the WQI. Water quality in the Little Manatee River
basin is considered to range from fair to good. There are no severe water quality problems
reported, but elevated nutrient and bacteria levels are attributed to runoff from agriculture (citrus
and row crops) and rangelands in the upper river reaches, and agriculture, septic tanks, package
wastewater treatment plants and fish farms in the downstream reaches. Encroaching residential
development, agriculture and increased phosphate mining are cited as potential threats to water
quality in the Little Manatee River in the future (Hand et al., 1996).
5.2.2 Estuarine waters
Water quality information for estuarine waters in the Little Manatee River and Cockroach Bay are
largely limited to sites monitored by the EPCHC and data collected during the District watershed
assessment in the late 1980s. The EPCHC monitors a suite of water quality parameters at a site
near the US Highway 41 bridge on the Little Manatee River and a site approximately in the middle
of Cockroach Bay. Yearly mean water quality values for these sites are regularly reported by the
EPCHC (Boler, 1998). Also, a discussion of water quality at these sites including trend analyses
and time-series plots is presented in the draft watershed management report prepared for
Hillsborough County by PBS&J (2001).
Information on the salinity regime of the Little Manatee River is also included in a USGS report by
Fernandez (1985) and reports stemming from the District’s watershed assessment in the late
1980s (Peebles and Flannery, 1991; Vargo et al., 1991). The location of the transition from fresh
to brackish waters in the Little Manatee is dependent on the amount of streamflow in the river.
The report by Fernandez (1985) includes a regression equation to predict the location of the
upstream extent of brackish water as a function of freshwater inflows. The extent of brackish
water was defined at the upstream location of waters greater that 0.5 parts per thousand (ppt)
salinity. During the dry season, brackish waters can extend 10 to 11 miles upstream of the river
mouth. Vargo et al. (1991) listed the locations of four surface water isohalines (0.5, 6, 12, and 18
ppt) on 26 dates during 1988, a year with large variation in flows. Peebles and Flannery (1991)
presented a plot of the location of these same isohalines in the river as a function of freshwater
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inflows. The response of these isohalines is curvilinear and very responsive to changes in flow
below the median flow of the river.
The only continuing long-term data for the estuarine reach of the Little Manatee River is at the
EPCHC station at the US bridge, located about 2.7 miles upstream of the river mouth. Mean
annual salinity values at the station in the Little Manatee River have ranged from about 6 to 14
ppt., placing this location in the mesohaline zone of the river (PBS&J, 2001). Salinity on individual
dates can vary considerably, however, as values between 0.5 and 28 ppt were recorded during the
two-year District watershed assessment.
Total nitrogen concentrations at the EPCHC station have averaged 1.1 mg/L, yielding a
characterization of fair water quality (Paulic and Hand, 1998). Total nitrogen values of greater
than 1.2 mg/L in estuarine waters is considered characteristics of poor water quality. For the
period of 1983 through 1998, PBS&J reported a declining trend for total nitrogen at the EPCHC
site. Total phosphorus concentrations also declined over the period of record. Chlorophyll a
averaged 7.7 micrograms per liter (g/L) for the period of record, with mean annual values ranging
from 5 to 11 g/L.
These values are considered to represent fair to good water quality based on comparisons to other
Florida estuaries (Paulic and Hand, 1998). However, studies conducted for the District watershed
assessment showed that chlorophyll a values in the lower portions of the Little Manatee River
estuary were generally lower and more stable than concentrations further upstream (Flannery et
al, 1991; Peebles and Flannery, 1991; Vargo et al, 1991). Mean chlorophyll a concentrations were
20 g/L at the 0.5 ppt salinity zone, which had an average location of 6.8 miles upstream.
Conversely, mean chlorophyll a concentrations at the 18 and 12 ppt isohalines, which were
located nearer the mouth of the river, were about 5 and 10 g/L, respectively. Dissolved
inorganic nitrogen, ortho-phosphorus, turbidity and dissolved organic carbon were also higher in
the upstream reaches of the tidal river (Peebles and Flannery, 1991; Vargo et al., 1991). As a
result, the single HCEPC station near US 41 does not represent the area of highest values for
nutrients and trophic state variables in the tidal reaches of the Little Manatee River. Nonetheless,
the stable and declining trends for nutrients and chlorophyll a at the HCEPC station are indicative
that water quality in the tidal reaches of the Little Manatee River is not getting any worse, at least
at that location.
Dissolved oxygen (DO) concentrations are an important concern for water quality and the overall
ecological health of rivers in the Tampa Bay region. Dissolved oxygen is critical for aquatic life and
values less than 2 to 3 mg/L can be considered hypoxic or stressful to aquatic organisms. The
state DO standard for instantaneous readings in estuarine waters is more conservative at 4 mg/L.
In addition to the EPCHC station at US 41, DO is measured throughout the tidal Little Manatee
River during the late summer as part of the EPCHC’s yearly monitoring of benthic
macroinvertebrate populations. Statistical summaries of DO concentrations in the Little Manatee
during 1996-1998 and 2000 are included in EPCHC reports by Grabe et al. (2000 and 2001a).
These reports found that day time DO readings in the tidal reaches of the Little Manatee are above
3 mg/L. Based on data from 1988-1989, Flannery et al. (1991) reported a gradient in summertime
DO in the tidal reaches of the river, as DO averaged about 5.2 mg/L at stations near the mouth of
the river but averaged between 3.4 and 4.2 mg/L at stations above river mile 4.
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Flannery et al. (1991) cautioned that their reported values were daytime readings and DO
concentrations at night could be appreciably lower. These authors cautioned that increased
nutrient loading in the Little Manatee watershed could act to reduce DO concentrations in the
tidal river, particularly in its upper reaches. The results for DO in the Little Manatee are striking
when compared to the Alafia River several miles to the north, where industrial pollution and
increased nutrient loading have been pronounced. Similar summertime sampling conducted for
the EPCHC benthic monitoring program found pronounced hypoxia in the Alafia, with numerous
DO values well under 2 mg/L (Grabe et al., 2001b). The results from the Alafia are indicative of
problems that can occur in tidal Florida rivers with experience excessive nutrient loading, and are
a case example of why nutrient loads and DO concentrations in the Little Manatee River should be
carefully managed.
Water quality for the EPCHC station in Cockroach Bay is regularly reported by the Hillsborough
County (Boler, 1998). Salinity at the EPCHC station is higher than in the Little Manatee River,
reflecting Cockroach Bay’s small watershed area and limited freshwater inflows. Analyses of data
from the EPCHC station in Cockroach Bay have been presented in two reports by PBS&J (1999,
2001). The results concerning changes in water quality are mixed. The Cockroach Bay Aquatic
Preserve Management Plan (PBS&J, 1999), concluded that concentrations of total phosphorus,
dissolved inorganic nitrogen, and fecal coliform bacteria had declined over the period of record.
The second report (PBS&J 2001), however, reported a significant increase in the Trophic State
Index (TSI) value for Cockroach Bay, with most values ranging between 60 and 70 TSI units.
These TSI values are comparatively high for other areas of Tampa Bay, indicative of poor water
quality (Hand et al. 1996). However, the shallow and confined nature of Cockroach Bay probably
contributes to these comparatively high TSI values.
The EPCHC has developed a Water Quality Index specifically for Tampa Bay which can be applied
to the Cockroach Bay site. Post Buckley (2001) calculated a WQI value of 55.8 for Cockroach Bay,
which can be characterized as poor water quality. However, the WQI showed a significant
increase over time, indicating improving water quality. Post Buckley (2001) also reported a
decreasing trend in total phosphorus and increasing trend for dissolved oxygen, indicating
improving water quality.
Waters in and around Cockroach Bay are classified as Class II waters for shellfish harvesting.
However, elevated fecal coliforms in the bay led to a temporary closure of shellfish harvesting by
FDEP (Paulic and Hand, 1994). However, fecal coliform concentrations in Cockroach Bay appear
to have declined over the period of record (PBS&J, 2001). Additionally, the National Oceanic and
Atmospheric Administration Mussel Watch Program identified an increasing trend for lead in
oyster tissue from Cockroach Bay (Paulic and Hand, 1994).
Water Quality in Terra Ceia Bay is monitored by the Manatee County Environmental Management
Department. Three stations within the bay and two outside the mouth of the bay have been
monitored on a quarterly basis since 1995. These data indicate the bay has generally good water
quality with few occurrences of low dissolved oxygen concentrations. Sediment chemistry and
benthic macroinvertebrate data have also been collected at 8 stations in Terra Ceia Bay since
1993. Based on data from 1993 to 1997, approximate 10 % of the bay’s bottom habitat was
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considered degraded based on the indices used, while more than 70 % of the bottom habitat was
considered healthy (Grabe, 1998).
5.2.2.1 Piney Point Phosphates
The water quality threat posed by the Piney Point Phosphates facility has received considerable
attention in recent months. This facility, located near the coast, adjacent to Port Manatee, was
shut down following the bankruptcy of Mulberry Phosphates. Consequently, the plant was no
longer able to continue to operate the pumps of the Piney Point phosphogypsum stack system
resulting in the accumulation of processed water. Discharged in sufficient quantities, this water
could severely impact water resources in the area. The FDEP has been the lead agency on this
issue. In addition, the Tampa Bay Regional Planning Council’s Agency on Bay Management has
convened a Task Force to formulate short and long-term solutions for the situation.
5.3 SOURCES OF WATER QUALITY DATA
5.3.1 United States Geological Survey
The United States Geological Survey collects, analyzes and reports water quality for two stations
within the Little Manatee River watershed at road crossings on the main stem of the river (US
Highway 301 and State Road 674). The data in many cases represent the best historical flow and
water quality data available. However, the USGS has within the last few years greatly reduced its
water quality monitoring program.
5.3.2 Florida Department of Environmental Protection
The FDEP’s Surface Water Assessment and Monitoring Program and Groundwater Quality
Monitoring Program were merged in 1996 to create the Integrated Water Resources Monitoring
(IWRM) Network. IWRM was developed to provide integrated, statewide information on the
important chemical, physical, and pertinent biological characteristics of surface water,
groundwater, and sediments and is designed to fulfill many monitoring, management and
regulatory needs. The data generated will help evaluate the status and trends of surface and
groundwater quality, meet FDEP 305(b) reporting requirements (which are used to rate the water
quality of surface waters in Florida), and establish Total Maximum Daily Loads.
IWRM employs a three-tiered approach to water quality monitoring. Each FDEP district is divided
into four super-basins called Group A, Group B, Group C and Group D. Each group contains one
or more hydrologic units. The Little Manatee River CWM area falls within Groups B and C of the
Southwest District. Tier I monitoring in Groups B and C is conducted by the District under
contract with FDEP.
There are two aspects to Tier I monitoring: fixed station monitoring and status monitoring. The
purpose of fixed station monitoring is to document temporal variability in specific locations within
watersheds (trend monitoring). Fixed station monitoring began in October 1998 and is conducted
monthly at 80 stations statewide; thirteen of which are located within District boundaries and are
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monitored by the District. One of these stations (Little Manatee River @ SR 301) is located in the
CWM area.
Status monitoring is conducted within groups on a five-year rotation (each group is monitored
once in a four-year period, with the first group repeated in year five). Status monitoring in the
Southwest District was completed in FY 2000 for Group B, and FY 2001 for Group C. This
monitoring involved collecting samples at 180 randomly-selected stations within each group; 30
stations each in the water resource classifications of low order streams (stream order 1-4), high
order streams (stream order > 4) plus canals, small lakes (10 hectares or less), large lakes (> 10
hectares), confined aquifers, and unconfined aquifers including springs. Data obtained through
Tier I monitoring will be used in the development of 305(b) reports and to delineate areas of the
state which need further and more intensive study.
Tier II monitoring will address the same parameters and six categories of water resources as those
of Tier I; however, it will focus upon specific waters requiring restoration, protection and/or TMDL
development. Basin management plans and best management plans will be developed during the
Tier II cycle. The monitoring efforts of Tier II will be conducted for the most part by FDEP, but
other stakeholders will be brought into the process as well.
Tier III is the regulatory stage of IWRM and involves monitoring of permitted activities and the
effectiveness of BMPs. FDEP will determine how monitoring is to be conducted, but the actual
monitoring effort will be the responsibility of the permittee and/or their contractors.
5.3.3 Environmental Protection Commission of Hillsborough County
The Environmental Protection Commission Hillsborough County maintains a monitoring program
for the regular collection and analysis of water quality samples from lake and stream stations
throughout Hillsborough County. Within the Little Manatee River and Cockroach Bay watersheds
there are four monitoring stations (EPCHC, 1995).
5.3.4 Manatee County Environmental Action Commission
The Manatee County Environmental Action Commission, hereafter referred to as the EAC, is
comprised of the same members as the Board of County Commissioners and is responsible for
overseeing the operations of the local independent environmental agency. The EAC consists of an
Administration Office and the three divisions of Air Quality, Natural Resources Management and
Water Quality.
The EAC Administration is charged with developing annual budgets, preparing deposits, reporting
activities to the Commission, assisting other divisions by researching environmental issues and
performing educational and community outreach on environmental issues.
The Environmental Management Department implements the environmental policies of the
Manatee County Comprehensive Plan and the environmental regulations of the Manatee County
Land Development Code in unincorporated Manatee County. This Division has primary
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esponsibility for coordination of the County's beach restoration program, habitat restoration
projects, and planning for environmental land acquisition and management.
The Air Quality Management Division preserves and protects the air quality in both the
unincorporated and incorporated portions of Manatee County through the administration of a
state contract and enforcement of the Manatee County's Code of Environmental Regulation.
The Water Quality Management Division protects, maintains and enhances the surface and
groundwater quality in Manatee County. This mission is carried out through a variety of
programs, water quality monitoring, conducting special studies, and monitoring compliance with
mandates of the Manatee County Comprehensive Plan. The Water Quality Division administers
various state contracts and programs. This Division also performs special studies on a one-time
or continuous basis, such as monitoring for the Sarasota Bay and Tampa Bay National Estuary
programs, water quality and quantity tracking and trend analysis in the county's two watersheds.
5.3.5 Southwest Florida Water Management District
The Southwest Florida Water Management District collected water quality data at a number of
sites in the Little Manatee River watershed as part of a basin-wide study during 1988 (Flannery et
al. 1991; Dames and Moore, 1991). Those data are available from the water management
District. Lake Wimauma is periodically sampled by the Ambient Monitoring Program (AMP) of the
District, which collects water quality information on 300 lakes District-wide. Samples are
collected from each lake on a three-year rotation (i.e., a group of 100 lakes is sampled in the
summer and winter each year; a second group is sampled the following year, and so on, until the
fourth year when the first group is sampled again). Samples are tested for a broad range of typical
water quality parameters, including nutrients, chlorophyll, metals and cations.
During the development of the CWM plans for the District, all eleven teams identified the need for
a District-wide long-term water quality monitoring network (WQMN) and/or additional water
quality monitoring sites within their watersheds. Based on this well documented need the CWM
WQMN was developed. This network will ultimately include surface and groundwater monitoring
sites; however, at present, only surface water sites are included. The CWM WQMN strategy
includes field sampling activities, laboratory activities, quality assurance, some additional sites and
a centralized water quality database. All the elements of the strategy are either in-place or being
actively pursued.
The primary goal of the CWM WQMN is to develop a reliable, temporally and spatially relevant
ambient monitoring data collection, analysis and distribution system. Ambient water quality data
are necessary to establish a long-term record of water quality and biological data for:
1) early detection of water bodies with declining water quality trends, which may benefit
from District or local government intervention;
2) documentation of water quality improvements associated with the implementation of
management strategies by the District or local governments;
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3) determination of the extent to which statutory water quality criteria or state/regional
water quality targets are met or violated total maximum daily loads and pollutant load
reduction goals;
4) identification of water bodies that may ultimately be included in the SWIM Priority
Waterbody List;
5) calibration of water quality models and the development of loading databases that
support event mean concentration calculations;
6) establishing long-term databases for water bodies representative of identifiable
geographical and ecological regions that can be used for comparative purposes in other
water body studies; and
7) establish a basis for effective response to citizen requests for water quality information.
The CWM WQMN is designed to complement other monitoring efforts by local, state and federal
agencies using data currently being collected by those entities and only sampling sites not being
monitored by other agencies. The primary agency programs from which data will be derived are:
the District, the USEPA, the USGS, FDEP, the Tampa Bay Estuary Program, local government
members of the Regional Ambient Monitoring Program (RAMP) and Florida Lake Watch.
The Little Manatee CWM team has been an active participant in the WQMN initiative. This
includes participation in efforts to identify and prioritize surface water monitoring needs
throughout the district. The monitoring sites recommended by the team for the Little Manatee
CWM area are listed below, in order of priority:
Ranking
Site Name
1 So. Fork Little Manatee River at 579
2 Marsh Branch in Ruskin at 15 th Street SE
3 So. Fork Little Manatee R at Taylor Grade
4 Cypress Creek at Kings Blvd.
5 Carlton Branch at SR 674
6 Howard Prairie Branch near Stanland Rd.
7 Curiosity Creek at Valroy Rd.
8 Dug Creek at Stafford Rd.
9 Pierce Branch at SR 674
10 Alderman Creek at Taylor Gill Rd.
11 Gully Branch at Unnamed Rd. east of CR 579
12 Unnamed Slough at Lightfoot Rd.
13 So. Fork Little Manatee R at Bunker Hill Rd. (situated 1
mile west of CR 39, off SR 62)
14 Little Manatee R near Ft Lonesome
15 Unnamed Creek at Flowers Rd.
16 Wimauma Drain at Unnamed Rd. east of CR 579
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17 North Fork of Little Manatee River
18 Little Manatee R near Wimauma
5.3.6 Florida Lakewatch Volunteer Monitoring Program
Florida Lakewatch is a volunteer program developed by the University of Florida to monitor water
quality in Florida lakes. Water quality samples are collected monthly on most program lakes, and
samples are tested for concentrations of chlorophyll a, total phosphorus, and total nitrogen. In
1993, the list of parameters was expanded for a large number of the participant lakes, to include
pH, total alkalinity, specific conductance, color, chloride, iron, silica, sulfate, calcium, magnesium,
sodium and potassium. Lakewatch is partially funded by the FDEP, and the data are provided to
FDEP for use in water quality assessments. In Hillsborough County, there are 120 lakes currently
in the program.
5.3.7 Hillsborough County Lake Monitoring Program (LaMP)
Hillsborough County, in cooperation with the SWFWMD and the University of Florida Lakewatch
Program, has enlisted volunteers for a lake monitoring program for nearly 120 lakes county-wide,
many of which are in the Hillsborough River watershed. The University of Florida Lakewatch
program is a volunteer monitoring program, with active volunteers on some 600 lakes statewide.
The program is supported in part by the Florida State Legislature through FDEP, and the data are
available to water management agencies, as well as the public. In Hillsborough County,
volunteers collect water samples and take measurements of water clarity monthly from their
lakes. The samples are dropped off at designated drop-off points where they are picked up and
taken to the University of Florida (UF) laboratory for analysis. At the UF laboratory, the samples
are analyzed for nutrients and chlorophyll a. The University of Florida Lakewatch staff also
provides training for volunteers in sample collection methods.
5.3.8 Hillsborough County Stream-Waterwatch Program
Stream-Waterwatch is a program initiated by Hillsborough County in 1998 to develop volunteer
monitoring of streams and rivers in Hillsborough County. In addition to collecting water
chemistry and biological samples, volunteers learn about principles of water management and
become more involved in resolving local issues affecting their flowing waters. The pilot
Stream-Waterwatch program was funded by the Florida Game and Freshwater Fish Commission
(now the Florida Fish and Wildlife Conservation Commission); funding is now shared between
Hillsborough County and the SWFWMD. As with the LaMP program, Stream-Waterwatch will
provide water managers and citizens with water chemistry and biological data for better assessing
stream conditions and identifying management issues.
5.4 REGULATORY AUTHORITY AND SPECIAL REGULATIONS
5.4.1 Surface Water Classifications
All surface waters in the state have been classified according to present and future most beneficial
uses (Chapter 62-302, F.A.C., Surface Water Quality). The chapter provides classification-specific
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water quality standards for physical and chemical parameters of surface waters. The Little
Manatee River over most of its length, and including all of its tributaries, is Class III waters.
Class I
Class II
Class III
Class IV
Class V
Potable water supplies
Shellfish Propagation or Harvesting
Recreation, Propagation, and maintenance of a
healthy, well-balanced Population of Fish and Wildlife
Agricultural Water Supplies
Navigation, Utility, and Industrial Use
5.4.2 Outstanding Florida Water Designation
In addition to the above surface water classifications, the Little Manatee River from State Road 674
to its mouth is designated as an Outstanding Florida Water. With the OFW designation, certain
special regulations that affect OFWs become effective, including:
62-640.770(4)(f), F.A.C., Domestic Wastewater Residuals ("the Sludge Rule") increases the
setback distance for land application of sludge from 200 feet to 3000 feet, and requires
that the setback area be vegetated.
62-312.080(3), F.A.C. Standards for Issuance or Denial of a Permit, states that no permit
shall be issued for dredging or filling which significantly degrades or is within an OFW.
Responsibility for Management and Storage of Surface Waters (MSSW) (Chapter 373, F.S.),
which provides for the permitting of stormwater pretreatment ponds, was delegated to the
water management districts. The Southwest Florida Water Management District's
guidelines (Chapter 40D-4, F.A.C.) require that developments which discharge to OFWs
provide treatment of a 50 percent greater volume of stormwater runoff than otherwise
required.
5.4.3 Cockroach Bay Aquatic Preserve
The Little Manatee River downstream from Highway 301 and the submerged lands associated with
Cockroach Bay and Little Cockroach Bay extending south from the mouth of the river are
designated as part of the Cockroach Bay Aquatic Preserve. The Cockroach Bay Aquatic Preserve
is managed by the Florida Department of Environmental Protection, in cooperation with
Hillsborough County. The original management plan for CBAP was published by the Florida
Department of Natural Resources in 1987. Since that time, the boundaries of the CBAP have
expanded into the Little Manatee River and public attention to the preserve has increased.
Hillsborough County’s Comprehensive Plan recognizes Cockroach Bay as a unique resource
management area. Several policies intended to afford protection to Cockroach Bay are included in
the Comprehensive Plan, including the formation of the Cockroach Bay Management Advisory
Team (CAPMAT), which was formed in 1993. In response to growing concerns regarding issues
concerning the aquatic preserve, CAPMAT in cooperation with several local agencies sponsored an
update of the management plan for the CBAP. That report (PBS&J, 1999) recommends action
plans to address issues concerning the CBAP.
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5.4.4 Terra Ceia Bay Aquatic Preserve
The Terra Ceia Bay Aquatic Preserve includes submerged and wetland areas within and adjacent to
Terra Ceia Bay including tidal waters of all tributaries including Frog Creek/Terra Ceia River,
McMullen Creek and Little Redfish Creek. All waters within the Aquatic Preserve are also
designated as Outstanding Florida Waters.
5.4.5 Domestic Wastewater Residuals
Areas of the Little Manatee River watershed are used for the land spreading of domestic residuals
(sludge). Residuals contain pollutants that have been removed from wastewater during the
treatment process. Domestic residuals are usually spread on land and allowed to dry. Thereafter,
they may be used as a soil supplement for certain agricultural uses. Application can also be made
directly to the site in wet state. Residual disposal sites must be approved by FDEP, and
groundwater monitoring at the sites is required to assure that pollution is not occurring. Chapter
62-640, Florida Administrative Code, Domestic Wastewater Residuals, regulates the activity. In
Manatee County, local land spreading standards for residuals have been adopted, which are more
stringent than existing State rules.
5.5 OTHER GOVERNMENTAL ACTIVITIES AND WATERSHED ACTIVITIES
The Little Manatee River extends over two counties, and includes several urban areas. All of these
governmental units share interests in the Little Manatee River watershed. In addition, the Florida
Department of Environmental Protection, SWFWMD, the Environmental Protection Commission
of Hillsborough County, Manatee County Environmental Action Commission and City of Palmetto
share regulatory responsibility for activities that potentially affect the water quality of surface and
ground water. Some of the major management and planning entities and programs concerned
with the Little Manatee River watershed are discussed in the following sub-sections.
5.5.1 Tampa Bay Surface Water Improvement Management Plan
Tampa Bay, the receiving water for the Little Manatee River, ranked number one on the District’s
Surface Water Improvement and Management (SWIM) program’s list of priority waterbodies in
need of restoration. The original SWIM Management Plan was approved by the SWFWMD
Governing Board and by FDEP in 1988 (SWFWMD 1992). The primary goals of the Tampa Bay
SWIM program are to reverse the environmental degradation of the Tampa Bay estuarine system;
to optimize water quality and habitat values, to support a thriving, integrated biological
community; and to ensure the maintenance of a productive, balanced ecosystem complimentary
with human needs and uses of the resource (SWFWMD 1992). The original Tampa Bay SWIM
plan identified 18 priority projects, all of which have either a direct or indirect effect on water
quality in sub-basin waterbodies, as well as Tampa Bay. These projects include water quality
assessment, prioritization of urban sub-basins (i.e., development of screening tools to estimate
the relative non-point pollutant loads for Tampa Bay sub-basins), habitat restoration and urban
stormwater rehabilitation projects. The SWIM Plan was revised in 1992, and is now being
considered for another update.
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5.5.2 Tampa Bay Estuary Program
The Little Manatee River drains into Tampa Bay, which is one of 22 estuaries in the United States
that are a part of the National Estuary Program (NEP). The NEP was created under the Clean
Water Act and is administered by the USEPA. The Tampa Bay Estuary Program (formerly Tampa
Bay National Estuary Program) was established in 1991 to assist the community in developing a
comprehensive plan to restore and protect Tampa Bay. The management committees are
composed of private and public agencies and organizations. The document, “Charting the
Course” management plan outlines the proposed action plans to address water and sediment
quality, and natural systems issues in Tampa Bay and its watershed (Tampa Bay National Estuary
Program, 1996).
Water quality reached a low-point in Tampa Bay during the mid to late 1970s, when widespread
blooms of algae clouded the bay waters. The algae blooms decreased the depth to which light
penetrated, resulting in the loss of large areas of seagrass. Increased loading of nitrogen was
identified as the cause of the algae blooms in the bay. Water quality has since improved. Most
water quality gains have been attributed to advanced wastewater treatment, which can remove up
to 90 percent of the nitrogen discharged to the bay. Municipal sewage treatment facilities now
contribute nine percent of the total nitrogen loadings to the bay, down from 40 percent in the
mid-1970s. As the contribution of point sources has declined, non-point sources have assumed
greater importance. Non-point sources of nitrogen will likely increase over the coming decades,
as the population of the Tampa Bay region continues to grow (Tampa Bay National Estuary
Program 1996).
The TBEP management objectives for water quality in Tampa Bay are to maintain and gradually
reduce in-bay loadings of nitrogen and total suspended solids. To achieve these objectives, the
TBEP management plan presents action plans addressing the stormwater runoff, wastewater,
atmospheric deposition, and toxic contaminant components of bay pollution. A schedule and cost
estimate is presented with each action plan, and the key or lead implementing agencies are
identified (Tampa Bay National Estuary Program, 1996).
The Tampa Bay SWIM program and the Tampa Bay Estuary Program are complementary
programs, and have worked together on all aspects of Tampa Bay restoration. Ultimately,
pollutant load reduction goals (PLRGs) will be set for Tampa Bay sub-basins. The process of
setting PLRGs brings together federal, state, district and local regulatory agencies to agree upon
the pollutant reductions necessary to achieve predetermined restoration goals. The process for
implementing PLRGs has not been determined, but creative methods for achieving compliance
with the sub-basin specific PLRGs, and for apportioning the pollutant reductions among the
various contributors should be possible.
5.5.3 Florida Department of Environmental Protection - Total Maximum Daily Loads
Development of Total Maximum Daily Loads (TMDLs) is one of the many initiatives of the Florida
Department of Environmental Protection’s Watershed Management Program. TMDLs provide a
tool to assess surface water quality problems and contributing sources of pollution. The approach
attempts to be specific, and non-arbitrary, by using numbers instead of describing problems and
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possible solutions. Based on Section 303(d) of the Clean Water Act, TMDLs are required for
surface waterbodies that do not meet applicable water quality standards after implementation of
technology-based effluent limitations. A map depicting these waterbodies by County is available
on the Department of Environmental Protection ‘s internet site at www.dep.state.fl.us.
As part of the TMDL effort, the Department may develop a watershed or basin management plan
that addresses some or all of the tributary basins to the water body. These plans will serve to fully
integrate the management strategies available to the state for the purpose of implementing the
TMDL and achieving water quality restoration. To date, the Department has assembled draft
plans for Tampa Bay and its tributaries, which addresses the Little Manatee River.
5.5.4 Hillsborough County
Hillsborough County has sponsored the preparation of a watershed assessment plan for the Little
Manatee River than includes assessments of the hydrology, water quality, and natural system
characteristics of the basin. The initiative’s end product will be a series of alternatives for
addressing flooding and water quality issues for consideration by local policy makers.
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5.6 ACTION PLAN: WATER QUALITY
ISSUE #1: RE-ASSESS WATER QUALITY TRENDS AND DISSOLVED OXYGEN
CONCENTRATIONS IN THE LITTLE MANATEE RIVER
BACKGROUND:
Studies published in the early 1990's show strong increasing trends for several constituents in the
Little Manatee River watershed that were attributable to agricultural land use (Flannery et al, 1991;
Dames and Moore, 1991). Changes in agricultural practices and increased water use efficiencies
in the last several years may, however, have alleviated some of these problems. A recent draft
report (PBS&J, 2001) includes trend analyses for several variables collected by the EPCHC.
However, trends and concentrations in the Little Manatee River should be re-examined using all
appropriate data for a wider array of variables (e.g., nitrate and sulfate) to determine if water
quality in the river is improving, degrading, or showing no change. If water quality problems
continue to persist, areas in the basin should be identified that are contributing to these
conditions.
There have also been periodic violations of Class III dissolved oxygen standards in the tidal
reaches of the Little Manatee River, with reported data limited to day time readings. There are
other data available for night-time dissolved oxygen concentrations, but these data have not been
analyzed. A more thorough study of dissolved oxygen concentrations in the Little Manatee River
estuary should be conducted that includes both day and night time values. If problems with
hypoxia are found, assessments should be conducted to determine causative factors.
STRATEGY:
Re-examine water quality trends and dissolved oxygen concentrations in the Little Manatee River
and evaluate factors contributing to these conditions. Assess the distribution of pesticide residuals
in the watershed. If high concentrations are found, assess areas the pesticides are originating
from and management practices that can be used to minimize pesticide transport.
ACTIONS:
1. Using existing data sources (USGS, EPCHC, SWFWMD, Manatee County), re-examine
trends in water quality constituents at all applicable sites in the Little Manatee River.
2. Evaluate dissolved oxygen concentrations in the Little Manatee River estuary during the
spring and summer months. Conduct sampling during day and predawn hours. If
problem conditions are observed, investigate factors contributing to such conditions.
RESPONSIBLE PARTIES: EPCHC, SWFWMD, FDEP.
TENTATIVE SCHEDULE:
1. Re-examine water quality trends in 2002.
2. Perform dissolved oxygen sampling of tidal river in spring and summer 2002.
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EXPECTED BENEFITS: Identify existing or potential water quality problems in the Little Manatee
River.
The following is a major District project addressing this issue.
Project: Hillsborough County-Lake and Streams Program
This is a continuing program with program goals of 1) monitoring water quality in 120 lakes and
20 streams; 2) training citizen volunteers to collect and measure water quality samples; and, 3)
training lake property owners in lake management techniques and general public education in
water resource and wetland preservation. The initiative also includes entering the data into
Hillsborough County’s Lake Atlas Site, and maintenance of the site and expansion of the lake atlas
into the Hillsborough County Watershed Atlas (which will include rivers and their tributaries).
Participants: Hillsborough County, Alafia River, Hillsborough River and Northwest Hillsborough
Basin Board.
Status: Ongoing.
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ISSUE #2: IMPLEMENT BEST MANAGEMENT PRACTICES TO REDUCE NON-POINT SOURCE
NUTRIENT LOADING TO THE RIVER
BACKGROUND:
In many areas of the watershed nutrient and sediment loading from agricultural lands could be
reduced by implementation of best management practices. Problem areas should be identified
where non-point source nutrient loading is excessive. Using methods established by the District
agricultural exemption program, best management practices should be implemented. For
operations that are exempt, best management practices should be encouraged if excessive
nutrient loading is documented.
STRATEGY:
Pursue the implementation of best management practices to reduce non-point source nutrient
loading to the river from agricultural lands.
ACTIONS:
1. In conjunction with the assessment of agricultural irrigation runoff and water quality trends
in the watershed, identify sub-basins where nutrient loading is high.
2. Identify those specific operations where implementation of best management practices
would significantly reduce non-point source pollution.
3. Based on status of the operation (exempt or non-exempt), recommend and implement
best management practices as appropriate.
RESPONSIBLE PARTIES: EPCHC, Manatee County, SWFWMD, FDEP.
TENTATIVE SCHEDULE:
1. Identify sub-basins where nutrient loading is high by 2002.
2. Identify those specific operations where implementation of best management practices
would significantly reduce non-point source pollution by 2002.
3.
4. Implement best management practices 2002 and after.
EXPECTED BENEFITS: Alleviation and prevention of water quality problems in the Little Manatee
River resulting from elevated non-pont source nutrient loading.
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ISSUE #3: ASSESS THE EFFECTS OF SEPTIC TANK DENSITIES ON NEARBY GROUND AND
SURFACE WATER QUALITY
BACKGROUND:
High septic tank densities now exist within the town of Ruskin. Ground and surface water quality
conditions, however, are poorly documented for the area. Studies should be performed in areas
of high septic densities to determine if water quality in those regions has been impacted. If so, the
feasibility and cost effectiveness of extending centralized sewer into those areas should be
assessed.
STRATEGY:
Studies should be performed in areas of high septic tank densities to determine if pollution of
nearby surface or ground waters is occurring. If problems exist, consideration should be given to
extending centralized sewer service into areas of high septic tank concentrations.
ACTIONS:
1. A water quality sampling program should be implemented in the region of high septic tank
densities in Ruskin.
2. If significant surface or groundwater pollution is occurring as a result of high septic
densities, the feasibility of extending central sewer system service to the area should be
evaluated.
RESPONSIBLE PARTIES: EPCHC, local health departments, SWFWMD.
TENTATIVE SCHEDULE:
1. Implement water quality sampling program by 2002.
2. If determined necessary, implement feasibility of extending central sewer system service to
the area should be evaluated by 2003.
EXPECTED BENEFITS: Prevention or alleviation of water quality problems associated with high
septic tank densities.
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ISSUE #4: ASSESSMENT OF EFFECTS OF SEWAGE WASTE RESIDUALS DISPOSAL ON
GROUND AND SURFACE WATER QUALITY
BACKGROUND:
Areas in the Little Manatee River watershed have been used for the disposal of solid sewage
wastes. Although ordinances are in place regulating this activity, data are sparse regarding the
effects of this sewage disposal on nearby surface and ground waters and the effectiveness of
related ordinances. An assessment of water quality in streams near areas of sewage waste
disposal should be conducted.
STRATEGY:
Assessments should be of surface and water quality in areas which have been used for the
disposal of sewage waste residuals. If problem conditions are found, ordinances concerning
disposal of these materials should be reviewed for their effectiveness.
ACTIONS:
1. Identify areas in the Little Manatee River watershed that are used for the disposal of
sewage waste residuals.
2. Design a surface water quality monitoring program to examine water quality in areas of
sewage residual disposal, including non-affected control sites.
3. Review the effective of existing ordinances for maintaining surface water quality and
suggested model ordinances if problems with existing ordinances are found.
RESPONSIBLE PARTIES: SWFWMD, FDEP, EPCHC, Manatee County.
TENTATIVE SCHEDULE:
1. Identify areas in the Little Manatee River watershed that are used for the disposal of
sewage waste residuals in 2002.
2. In 2002, design a surface water quality monitoring program to examine water quality in
areas of sewage residual disposal, including non-affected control sites.
3. In 2002, review the effectiveness of existing ordinances for maintaining surface water
quality, and suggested model ordinances if problems are found.
EXPECTED BENEFITS: Protection of water quality in Little Manatee River.
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ISSUE #5: PUBLIC LAND ACQUISITION TO PROTECT WATER QUALITY
BACKGROUND:
Both the Southwest Florida Water Management District and Hillsborough County have placed
lands in the Little Manatee River watershed in public ownership. Various studies have shown that
the placement of buffer strips around streams and other waterbodies is an effective way to protect
water quality. Land acquisition programs should continue in the Little Manatee watershed in
order protect the resource including its water quality. The preservation of lands near the river
channel should act to maintain water quality and biological integrity of the Little Manatee River.
STRATEGY:
Continued public land purchases in the watershed should include selection criteria to protect
water quality in the Little Manatee River and its tributaries.
ACTIONS:
1. Incorporate water quality criteria in the selection process for land acquisition. Such
criteria can be used to protect areas that have good water quality or to restore water
quality in areas where intensive land uses may be converted to vegetated land cover.
2. Prioritize lands in the Little Manatee River watershed for acquisition based on value to
natural resources, including habitat value and relations to water quantity and quality.
RESPONSIBLE PARTIES: SWFWMD, Hillsborough County, Manatee County.
TENTATIVE SCHEDULE:
Continue existing land acquisition programs.
EXPECTED BENEFITS: Protect natural resources associated with Little Manatee River.
The following is a major District project addressing this issue.
Project: Little Manatee River Corridor.
In 1992, the Governing Board authorized the acquisition of lands within the Little Manatee River
project in Hillsborough and Manatee counties. The Little Manatee River project, consisting of
7,050 acres, acquired in fee simple, contains parcels of land along the Little Manatee riverine
corridor from downstream estuarine waters, to the river’s headwaters. Dense forest dominates
the land along the river’s floodplain with the adjoining uplands being comprised of a mixture of
pine flatwoods, mixed hardwoods shrubs and brushlands. An additional 27,000 acres have been
authorized for simple acquisition. The District has entered into an interlocal agreement with
Hillsborough County wherein the County has lead responsibility for land jointly purchased by the
agencies.
Participants: Alafia and Manasota Basin Boards and Hillsborough County.
Status: Ongoing.
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ISSUE #6: DATA GAPS AND MONITORING NEEDS: NO SURFACE OR GROUND WATER
QUALITY DATA FOR MANY AREAS OF THE LITTLE MANATEE RIVER WATERSHED
Sub-issue: There are no historical or current water quality data for the Alderman Creek, and very
limited water quality data for Cypress Creek and the South Fork of the Little Manatee River. A lack
of adequate data for these basins will hamper the monitoring of changes in water quality, and will
make it more difficult to efficiently manage the water quality in these sub-basins.
Sub-issue: Parameters including mercury, arsenic, cadmium, copper and lead are infrequently
sampled in most waters. In the case of mercury, the laboratory detection limit (typically between
0.1 and 0.5 µg/l) is often much greater than the state water quality standard (0.012 µg/l). Many of
the early records in the STORET (FDEP’s Storage and Retrieval) database dating to the early 1970s
suggest that concentrations of lead and mercury in the Little Manatee River exceed state
standards, but it is unclear if the reported concentrations actually exceeded the laboratory
detection limits. Furthermore, sample contamination may also be a problem when trying to
detect the extremely small concentrations represented by many of the state standards.
Determining if these and other metals exceed the state standards for water quality samples is
often not possible from the historical data and for most present-day data. The contaminants of
concern in Tampa Bay were polycyclic aromatic hydrocarbons (PAHs, benzo (a)anthracene and
benzo(a)pyrene). Lower priority contaminants of concern were arsenic, cadmium, chromium,
copper, mercury, as well as the PAHs chrysene, fluoranthene, phenanthrene, and poly-chlorinated
biphenyls (PCBs).
Sub-issue: Atmospheric deposition of airborne substances and particles is a potential source of
nutrients and toxic materials in the Little Manatee River watershed. A recently completed nitrogen
budget for Tampa Bay, which includes the Little Manatee River watershed, suggests that as much
as 27 percent of the nitrogen and 31 percent of the total phosphorus entering the Bay comes from
rainfall and dry deposition directly on the surface of the Bay (Zarbock et al. 1994). Moreover, U.S.
Environmental Protection Agency sponsored studies suggest that as much as 67 percent of the
loading of total nitrogen delivered to Tampa Bay may originate from aerial deposition on the
Tampa Bay watershed (Dixon 1994). In addition to nutrients, other contaminants in atmospheric
deposition include zinc, lead, mercury, cadmium, copper, and other metals. More data will be
necessary to accurately determine the distribution of pollutants of aerial origin in the watershed.
Sub-issue: There is a need for continuous and efficient groundwater quality monitoring to detect
potential pollution problems before they become widespread. In some areas of the Little Manatee
River Basin, groundwater quality samples may be collected infrequently and/or monitoring wells
may be sparsely distributed in space. As a result, there is the potential for groundwater pollution
to go unnoticed until the problem has become widespread. The problems reflect the fact that the
need for ongoing water quality data collection must be balanced with other objectives. Some
government agencies, such as the USGS, have reduced the number of wells from which water
quality data is collected due to budget restrictions. There is, however, the potential to maximize
data collection efforts and minimize environmental costs by optimizing the spacing and timing of
water quality sample collection. The water management districts are funding a study to examine
the temporal variability of groundwater quality. The study results may indicate that semi-annual
sampling, rather than quarterly sampling, is sufficient to characterize water quality changes,
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allowing more wells to be sampled with the same budget. A similar study could be performed to
identify an optimal spatial network of groundwater quality wells.
Sub-issue: There is no comprehensive map or report which identifies the location of all potential
pollution sources in the Little Manatee River basin. To thoroughly delineate areas requiring
groundwater quality protection, it is necessary to identify both areas susceptible to groundwater
contamination and the location of potential pollution sources. Unfortunately, information
regarding potential pollution sources is distributed amongst numerous government agencies. The
FDEP has data regarding the location of landfills and Superfund sites. Local land use maps may
show the locations of septic systems and industrial and agricultural operations. The Department
of Transportation may have information regarding the location of borrow pits used for road
construction. The SWFWMD has information regarding the location of agricultural, commercial,
industrial and mining operations which have water use permits.
The locations of some pollution sources are unknown and would require additional data collection
and evaluation. A gasoline plume is an example of groundwater contamination where the location
of the original pollution source may be unknown. A comprehensive identification of all potential
pollution sources within the Little Manatee River watershed would involve a significant
cooperation among numerous agencies.
Sub-issue: Due to limitations of the DRASTIC methodology in areas of karst geology, additional
methods should be developed and applied to identify areas susceptible to groundwater pollution
in the Little Manatee River watershed. The DRASTIC methodology, while useful in many respects,
does not account for all of the factors affecting the potential for groundwater pollution in karst
hydrogeologic systems. An alternative approach used by Swancar and Hutchinson (1992) is to
evaluate the chemical and isotopic composition of groundwater to identify high recharge areas
which are more susceptible to contamination. The Swancar and Hutchinson study presented
regional patterns in the groundwater pollution potential for the entire District. Groundwater
pollution potential maps, however, were not developed at the watershed or local scale. An
improved map of the groundwater pollution potential in the Little Manatee River watershed could
be created using Swancar and Hutchinson’s approach or a revised DRASTIC methodology. A
revised DRASTIC methodology is currently being developed through a cooperative effort between
the FDEP, Florida Geological Survey, U.S. Geological Survey, and the water management districts.
The revised methodology is termed the Florida Aquifer Vulnerability Assessment (FAVA).
Sub-Issue: Limited groundwater quality data are available for the surficial aquifer in the coastal
portion of the Little Manatee River watershed. Generalizations regarding coastal groundwater
quality in the surficial aquifer are based on regional water quality data combined with an
understanding of the local hydrogeology. The nearest coastal wells are located about two miles
outside the watershed boundary. The coastal area is particularly important due to the potential
influences of the Terra Ceia Bay, Cockroach Bay, Little Manatee River and Tampa Bay on
groundwater quality.
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Sub-issue: The extent and the sources of Cryptosporidium and Girardia contamination of the Little
Manatee River are not well known. It is suspected that dairies, feedlots and other high-density
animal husbandry operations in the watershed may be significant sources.
BACKGROUND:
There are no surface or ground water quality data for many areas of the Little Manatee River
watershed. Furthermore, the interval, frequency, and quality of existing data are often inadequate
and/or poor, limiting its usefulness to managers and planners for making informed decisions.
STRATEGY:
Improve efficiency and coordination in water quality data collection within the District, and among
agencies.
ACTIONS:
1. Use water quality information (ambient assessments) to prioritize river reaches and
associated basins for monitoring.
2. Compile a comprehensive map of all monitoring sites in the Little Manatee River
watershed, including responsible agencies, frequencies, and parameters sampled.
3. Develop a system to exchange information and coordinate sampling procedures and
protocols among all agencies and interested entities.
RESPONSIBLE PARTIES: SWFWMD, FDEP, USGS, Hillsborough County, Manatee County
TENTATIVE SCHEDULE: Inventory all water quality monitoring sites in the basin in 2002.
EXPECTED BENEFITS: Additional information on ground and surface water issues to better identify
management needs.
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ISSUE #7: GROUNDWATER PUMPING DISCHARGE EFFECTS ON SURFACE WATER QUALITY
BACKGROUND:
The Little Manatee River and its tributaries receive discharge from agricultural irrigation waters in
many reaches. This may result from the direct runoff of excess irrigation waters, or from
groundwater interflow resulting from supplementation of the surficial aquifer. Generally
increasing flow from irrigation waters represent an inefficient use of the resource, and has effects
on the water quality and possibly the biology of the river.
STRATEGY:
Determine regions of the watershed where significant quantities of irrigation water enter the river,
and determine the magnitude of this flow. Incorporate best management practices to reduce the
flow of irrigation water to the river.
ACTIONS:
See Issue #3 in Water Supply and Issues #1 and #2 in Water Quality.
RESPONSIBLE PARTIES: SWFWMD, FDEP, USGS, Hillsborough County, Manatee County
TENTATIVE SCHEDULE:
See Issue #3 in Water Supply and Issues #1 and #2 in Water Quality
EXPECTED BENEFITS: Reduced groundwater pumping impacts.
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ISSUE #8: ASSESS THE DISTRIBUTION OF PESTICIDE RESIDUALS IN THE WATERSHED
BACKGROUND:
The Little Manatee River watershed has extensive agricultural land use with accompanying use of
pesticides (insecticides and herbicides). In many reaches of the watershed, agriculture is in very
close proximity to the channel of the river or its tributaries with documented effects on nutrient
loading. To date, there has been no assessment of the distribution of pesticide residuals in the
Little Manatee River watershed.
STRATEGY:
Perform an assessment of the distribution of pesticide residuals in the Little Manatee River
watershed. In areas, where high concentrations of residuals are found, evaluate the land use
practices contributing to these occurrences and evaluate best management practices that could
alleviate the transport of pesticides to the river and its tributaries.
ACTIONS:
1. Design a study to measure the spatial distribution of pesticide residuals in the sediments
of the Little Manatee River and its tributaries.
2. In areas where high concentrations of pesticide residuals are found, evaluate and
implement management strategies to reduce pesticide loadings.
RESPONSIBLE PARTIES: FDEP, SWFWMD, Hillsborough County, Manatee County.
TENTATIVE SCHEDULE:
1. Perform assessment of pesticide residuals in 2002.
2. Evaluate best management practices to reduce pesticide loading in 2003.
EXPECTED BENEFITS: Reduced pesticide residual threat.
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ISSUE #9: INTER-/INTRA-AGENCY COORDINATION
Sub-issue: Due to the presence of potential pollution sources within the Little Manatee River
watershed, proactive strategies are needed for long-term groundwater quality protection. Areas
requiring groundwater quality protection include recharge areas, existing and potential future
wellfields, areas highly susceptible to groundwater contamination, and ground waters adjacent to
surface water supplies. The majority of the land area within the Little Manatee River basin falls
into one of these categories. High density septic tank usage and dairy farming pose a potential
water quality threat.
General strategies for groundwater quality protection include regulations, land use management
practices, water quality monitoring, and land acquisition. Regulations and land use management
practices can prevent potential pollution sources from being located near areas highly sensitive to
groundwater contamination. Wellhead protection programs are one type of regulatory measure
that is used to protect groundwater quality in Florida. Wellhead protection programs provide
groundwater quality protection by delineating areas to be protected and restricting activities
within those areas. The FDEP developed a state-wide wellhead protection rule which became
effective in May 1995 (Chapter 62-521, Florida Administrative Code). The rule designates a
wellhead protection area (WHPA) as the area within a 500-foot radial distance from a potable
water well. Many activities regulated by FDEP are restricted within WHPAs. Activities regulated in
WHPAs include reuse and land application projects, groundwater discharges, phosphogypsum
stacks, underground and aboveground storage tanks, and wastewater treatment and solid waste
disposal facilities. In addition to the state-wide rule, some local governments have developed
their own wellhead protection ordinances. Within the Little Manatee River basin, Hillsborough
County has developed wellhead protection ordinance.
Water quality monitoring can identify changes in groundwater quality which may be indicative of
pollution problems. The need for groundwater quality monitoring is discussed as a separate issue.
Land acquisition programs can be used to purchase and preserve environmentally sensitive areas
such as riverine corridors and recharge areas. Issues regarding land acquisition are discussed
within the Natural Systems section of this report.
Sub-issue: There is no regulatory process in place to ensure that water quality targets and PLRGs,
once selected, will be achieved. Pursuant to state water policy, water quality targets and PLRGs
have been developed by SWIM for the Lake Thonotosassa basin. Pollutant Load Reduction Goals
are also being developed for Tampa Bay, the Hillsborough Bay portion of Tampa Bay and the
Tampa reservoir of the Hillsborough River. However, the District, as well as other state and local
regulatory agencies, have not yet identified ways in which these targets and goals will be
incorporated into the regulatory process. If successful incorporation into the regulatory process
does not occur, it is unlikely that selected water quality targets and PLRGs will be achieved. This
issue, which is crucial to the District’s water quality management efforts, is currently being
addressed for the Tampa Bay watershed by the management conference of the Tampa Bay Estuary
Program. The management conference includes representatives of local governments within the
watershed, as well as local, regional, state and federal regulatory agencies. Discussions are
currently underway concerning procedures that will be adopted by local governments and the
regulatory agencies in an effort to ensure that cumulative pollutant loadings from point and non-
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point source discharges within the Tampa Bay watershed are consistent with the resource-based
water quality targets and PLRGs developed for the bay. An analogous effort is needed for the Little
Manatee River watershed.
BACKGROUND:
As the population in the Little Manatee River watershed, and the encompassing region continues
to expand, competing uses for the limited water will be the source of greater conflict. Ensuring
that the available water is fairly and equitably distributed will demand coordination between the
many agencies and public interest groups concerned with water quality management.
STRATEGY:
The Interim goal is to develop strong, possibly formal, links and mechanisms between agencies,
within agencies and with the public to coordinate and communicate water quality issues and
activities.
ACTIONS:
1. Expand and formalize the Little Manatee River CWM workgroup (or other task force
groups as appropriate) as a forum for the presentation of data, ideas, issues and conflicts
for discussion and consensus resolution. A single, public workgroup for the Little Manatee
River watershed would be able to address issues from a watershed perspective and
coordinate activities that have consequences for multiple AORs.
2. Support the District's Database Users Group (D-BUG) efforts to ensure availability and
transparency of information contained in District databases. Make District databases
widely available to outside agencies and the public, possibly through the Internet.
RESPONSIBLE PARTIES: SWFWMD, USGS, FDEP, Hillsborough County and Manatee County
TENTATIVE SCHEDULE: Under development.
EXPECTED BENEFITS: Improved coordination and cooperation on important issues.
Improved management of the resource.
The following is a major District project addressing this issue.
Project: Quality of Water Improvement Program.
Pursuant to F.S. Ch. 373.206, any abandoned artesian well having a detrimental impact on the
District's water resources must be properly plugged. The District's Quality of Water Improvement
Program provides funding assistance to landowners to come into compliance with the statute. To
increase landowner cooperation and the number of abandoned artesian wells plugged annually,
without increasing staff levels, the District's Governing Board has allocated matching funds to
augment the Alafia River, Hillsborough River, Northwest Hillsborough, Pinellas-Anclote River,
Peace River and Manasota Basins’s Quality of Water Improvement Program budget to maintain
the Funding Assistance Initiative since January 1, 1994. The Funding Assistance Initiative was
designed to reimburse landowners up to 100 percent of the cost to have their abandoned artesian
wells plugged, with a maximum District reimbursement of $5,000 per well and $15,000 annually
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per landowner. This incentive has increased landowner cooperation and the number of wells
plugged annually. Under the 50/50 cost sharing program, Quality of Water Improvement Program
plugged an average of 50 wells per year. Under the Funding Assistance Initiative, the Quality of
Water Improvement Program has reimbursed an average of approximately 200 wells per year.
Participants: Alafia River, Hillsborough River, Northwest Hillsborough, Pinellas-Anclote River,
Peace River and Manasota Basin Boards.
Status: Ongoing.
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ISSUE #10: TREATMENT AND USE OR DISPOSAL OF PINEY POINT’S PROCESS WATER
The Piney Point Phosphates phosphoric acid plant and associated phosphogypsum stack system is
located adjacent to Port Manatee, in the southern part of the Little Manatee River CWM study
area. The plant was built approximately 35 years ago, and has been operated by five different
owners, most recently Mulberry Phosphates. In mid-October 1999, the Piney Point Phosphates
facility shut down production, following bankruptcy of Mulberry Phosphate. Consequently, the
plant was no longer able to continue to operate the pumps of the phosphogypsum stack system,
and water stored on and in the stacks started to accumulate in potentially dangerous amounts. In
October 2001, the USEPA was forced to take emergency action to take over the operation of the
phosphogypsum stack system. In November 2001, FDEP assumed the operation of the Piney
Points phosphogypsum stack system, and under a FDEP emergency order phosphogypsum stack
water was discharged to Bishop Harbor for 19 days. The emergency order was necessary to
alleviate risks that a break in the Piney Point retaining dam would cause a catastrophic spill of
process water.
The initial discharges to Bishop Harbor contained over 16 tons of nitrogen. The previously
approved TBEP 2000-2005 Nitrogen Management Goal for Lower Tampa Bay is to reduce or
preclude the previous nitrogen loading rate by 25.35 tons per year by the year 2005, or about 5
tons per year for each of those years. The Department of Environmental Protection estimates that
it will be necessary to eliminate an additional 260 million gallons of process water from the stack
system before the end of the year to keep safe levels in the phosphate ponds on top of the stack.
In addition, 200-300 million gallons of process water per year must be eliminated until the stack is
permanently closed (an estimated 20 + years).
Groundwater monitoring has also detected a plume of contaminated groundwater in the vicinity of
the unlined phosphate stacks. This issue should be addressed in the long-term stack closure
strategy.
In January 2002, the Agency on Bay Management convened a Task Force to make
recommendations for short and long-term options for process water elimination, and for
monitoring effects of the November 2001 discharge to Bishop Harbor. The Department of
Environmental Protection is determining the cost and feasibility of each of the suggested
elimination options, and intends to implement one or more of the options. The Department has
also conceptually approved the monitoring elements recommended by the Task Force, and will be
developing a stack closure strategy.
STRATEGY:
Adequate treatment and use or elimination of the Piney Point Phosphate process water, and
adequate water quality monitoring.
ACTIONS:
1. Continue participation on ABM Task Force for identifying short and long-range solutions
for issue.
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2. Support cooperative funding proposals that involve the treatment and reuse of processed
phosphate water.
3. Pursue and support increased water quality monitoring in the area.
RESPONSIBLE PARTIES: FDEP, for overall implementation; Agency on Bay Management, Manatee
County, EPCHC, Hillsborough County, SWFWMD and private phosphate companies and other
private interests.
EXPECTED BENEFIT: Prevent water quality impacts due to phosphate industry.
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CHAPTER VI. NATURAL SYSTEMS
INTRODUCTION
As evidenced in Chapter 2 (Little Manatee River Watershed Description), environmental issues
related to the watershed are the product of human impacts within the area. The watershed has
undergone significant transformation from forested uplands and wetlands to a mixture of urban,
agricultural, mining, and relic intact biological communities. This pattern of land conversions and
its requisite infrastructure elements (e.g., roads, utility systems, landfills, etc.) will continue to
shape conditions within the remaining natural systems in the Little 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 alteration of the watershed’s ecosystem, and 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, ecosystembased
management decisions are made and implemented to insure the ecological viability of the
region’s natural systems. As such, this plan recommends the practice of “total ecosystem
management” to reach goals detailed throughout each area of responsibility. “Total ecosystem
management” refers to the proper management of, when feasible, any and all variables that affect
the viability of the area’s ecosystem. To properly implement total ecosystem management,
management goals must be defined identifying the target carrying capacity of the environment for
both human and non-human populations (see Issue #1 below for additional information and a
management strategy). Total ecosystem management should be a dynamic process, adjusting to
changing needs and requirements of the ecosystem. The process will require evaluations of how
effective management techniques are working, with management changes implemented as
warranted to meet goals set for the ecosystem. For planning and implementation purposes, issues
and strategies to address those issues are considered to be for a 100-year timeframe (2001-2101).
Past and projected land development throughout the watershed's sub-basins will continue to
produce adverse impacts to natural systems as more natural lands are altered. Without
management of the resources, 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. Low
intensity agricultural lands that retain portions of natural areas and forest cover are of secondary
ecosystem support value, as buffers or wildlife corridors are also at risk.
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, requests/demands for high
intensity and consumptive uses of natural resources, recreational uses, as well as becoming
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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. Water diversions, impoundments, aquifer withdrawals,
and other removals interplay with the total water budget for the area, a water budget that
originates with a variable hydrologic cycle. All human and ecosystem needs depend upon the
same water budget, but humans increasingly are disrupting 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” chapters of this management plan for specific details concerning these two
parameters.
6.1 SOURCES FOR NATURAL SYSTEMS INFORMATION
Information in the form of maps, aerial photographs, Geographic Information System databases,
consultant reports, model analyses, monitoring records, and field observations is available from
the following sources for the Little Manatee River and Terra Ceia Aquatic and Buffer Preserves.
Information can also be obtained from the provided literature review.
6.1.1 Southwest Florida Water Management District:
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).
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 Program: research studies, progress
reports and inventories for restoration sites, water quality monitoring and model analyses,
consultant reports, etc.
6.1.2 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.
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Management Plans for the Terra Ceia Aquatic and Buffer Preserve: Florida Department of
Environmental Protection’s management plans for the two preserves, inclusive of historical
perspectives, habitat restoration goals (in coordination with the SWIM Program of the
District), and public access and facilities.
6.1.3 Florida Fish and Wildlife Conservation 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.
Biodiversity maps.
6.1.4 U.S. Fish and Wildlife Service:
National Wetlands Inventory (wetland maps, classification, acreages).
6.1.5 Miscellaneous:
Audubon Society Christmas Bird Counts (published in: American Birds).
Manatee County GIS mapping.
6.2 LAND ACQUISITION FOR RESOURCE PROTECTION AND CONSERVATION
As one of the fastest growing states in the nation, Florida is experiencing many of the side effects
that accompany rapid population growth. The state’s uniqueness and diverse natural resources,
which attract tens of millions of visitors annually, are disappearing at a rapid rate as more and
more areas are being developed to accommodate the growing population. The state of Florida,
the water management districts, local governments and others, however, are strongly committed
to conserving this natural heritage and have instituted land acquisition programs for that purpose.
The following discussion summarizes the various land acquisition programs of relevance to the
Little Manatee River watershed. (See Atlas map 10 for a distribution of the watershed’s natural
systems, and map 11 for a distribution of conservation lands within the watershed.)
6.2.1 Conservation and Recreation Lands Program: Florida Department of Environmental
Protection’s Conservation and Recreational Lands (CARL) program has long been Florida’s major
public environmental land acquisition program for the protection and conservation of its natural
heritage. Originally funded solely by mineral-extraction severance taxes and documentary stamp
fees, the creation of Preservation 2000 provided financial stability for the program. The
watershed’s Little Manatee State Recreation Area and Terra Ceia Aquatic Preserve area have
benefitted from this program.
6.2.2 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
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Southwest Florida Water Management District since 1981. In the Little Manatee River watershed,
SOR funds have been combined with P2000 funds and land acquisition monies from Hillsborough
County to purchase 7,050 acres of land.
6.2.3 Preservation 2000: Preservation 2000 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. As indicated above, in the Little Manatee watershed
P2000 funds have been used in conjunction with other funding programs.
6.2.4 Hillsborough County Environmental Lands Acquisition and Protection Program: The
Hillsborough County Environmental Lands Acquisition and Protection Program (ELAPP) is an
important, locally-supported land acquisition program. This program has been extremely active in
the Little Manatee watershed, resulting in partnerships that have placed thousands of
environmentally sensitive lands in public ownership.
6.2.5 Manatee County Environmental Lands Management and Acquisition Committee: 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), and could target tracts within the Little Manatee River watershed. In addition, Manatee
County’s voters are expected to consider, in the near future, funding for a local land acquisition
program.
6.2.6 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, F.S.). The trust operates
within the Florida Department of Community Affairs (DCA) 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. This funding source has not been used to acquire any
properties within the Little Manatee watershed. It is considered, however, an important available
funding source.
6.2.7 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. In addition, TNC 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 landowners achieve their conservation objectives.
Additionally, TNC 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.
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6.2.8 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. TPL will also provide training and technical assistance
to private landowners, local land trusts, and government agencies to enhance their land
conservation goals.
6.2.9 Florida Forever: In 1999, the Florida Legislature passed the Florida Forever Act to serve as a
successor to the P2000 program. Florida Forever has natural resource protection objectives that
are similar to those of P2000, and requires that all lands acquired through the program be
managed for multiple-use purposes where compatible with the resource values and management
objectives for such lands. “Multiple-use” includes, but is not limited to, outdoor recreational
activities, water resource development projects, and sustainable forestry management objectives.
In addition, each Water Management District must develop 5-year work-plans that integrate their
existing SWIM plans, SOR land acquisition lists, stormwater management projects, proposed
water resource development projects, proposed water body restoration projects, and other
properties or activities that would assist in meeting the goals of Florida Forever.
6.3 ALTERNATIVE INITIATIVES FOR NATURAL RESOURCES PROTECTION
Several initiatives have emerged that attempt to enhance protection and management of the
watershed's natural resources by broadening, improving, developing and integrating management
and protection options.
6.3.1 Department of Environmental Protection: The Department’s Watershed Management
Program was created to foster better stewardship of Florida’s ground and surface water resources.
Working with other state agencies, water management districts, local governments, and the
private sector, the bureau coordinates the collection, data management, and interpretation of
monitoring information to assess the health of our water resources; develops watershed-based
aquatic resource goals and pollutant loading limits for individual waterbodies; and develops and
implements management action plans to preserve or restore waterbodies. These activities are
undertaken using the rotating basin approach that assures that the watershed plans for each of the
state’s watersheds are evaluated and updated every five years.
6.3.2 Southwest Florida Water Management District: The District’s Comprehensive Watershed
Management Program, which includes the Little Manatee River CWM initiative, has been
established to improve the management of water and related natural resources within the District.
This initiative integrates a wide variety of resource activities to employ a watershed approach to
resource management. The initiative is considered a priority by the District’s Governing Board
and Alafia River and Manasota Basin Boards.
6.3.3 Department of Community Affairs: This Agency is responsible for implementation of the
Local Government Comprehensive Planning and Land Development Regulation Act of 1985. This
act directs each local government within the State to guide future growth and development within
its jurisdiction. To ensure that future growth is compatible with the natural resources of an area,
the plan must evaluate and recognize the significant of natural resources and provide for their
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protection or preservation. Manatee and Hillsborough counties and the City of Palmetto have
each adopted a comprehensive plan, and land development regulations and ordinances for
implementing these plans.
6.3.4 Agriculture Clean Water Program: 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 U.S. Soil Conservation Service. 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.
6.3.5 Tampa Bay Estuary Program: This organization is responsible for the development and
implementation of the Comprehensive Conservation and Management Plan for Tampa Bay.
6.3.6 Comprehensive Plans for City of Palmetto and Manatee and Hillsborough Counties: Provide
policy information for land use decisions for the respective local governments.
6.3.7 Little Manatee River Land/Water Linkage Initiative: The District’s Alafia River Basin Board and
Hillsborough County jointly funded the initiative to provide a forum for citizen involvement and
input into development of the CWM plan for the Little Manatee River and Hillsborough County’s
growth management initiatives. This initiative has involved several months of facilitated work
sessions with local stakeholders to identify issues and preferred management strategies for land
and water for the CWM Plan and Hillsborough County’s growth management plan. Information
and recommendations generated during the sessions are reported in Little Manatee River
Watershed Plan Land/Water Linkage Project Staff Report.
The land/water linkage report is an important part of the watershed planning process for the Little
Manatee River area. Recommendations contained in the report will be heavily relied on for
project identification and development.
6.4 STATE REGULATORY PROGRAMS
6.4.1 The State Stormwater Rule, Chapter 17-25: This Florida legislation provides requirements for
treatment of stormwaters prior to its discharge to waters of the state.
6.4.2 Outstanding Florida Waters: Outstanding Florida Water designation was developed to
provide additional protection to special waters recognized for their exceptional ecological and
recreational significance. Terra Ceia Aquatic Preserve and the Little Manatee River, from State
Road 674 to its mouth, have been given the OFW designation. The OFW program is administered
by the Department of Environmental Protection, and surface waters within the program are given
additional special protection by the following regulations:
62-640.770(4)(f), F.A.C., Domestic Wastewater Residuals ("the Sludge Rule") increases the
setback distance for land application of sludge from 200 feet to 3000 feet, and requires
that the setback area be vegetated.
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62-312.080(3), F.A.C., Standards for Issuance or Denial of a Permit, state that no permit
shall be issued for dredging or filling which significantly degrades or is within an OFW.
Responsibility for Management and Storage of Surface Waters (Chapter 373, F.S.), which
provides for the permitting of stormwater pretreatment ponds, has been delegated to the
water management districts. The Southwest Florida Water Management District's
guidelines (Chapter 40D-4, F.A.C.) require that developments that discharge to OFWs
provide treatment of a 50 percent greater volume of stormwater runoff than otherwise
required.
6.4.3 Mine Reclamation Nonmandatory Reimbursement Program: This program was designed to
provide funding for reclamation of eligible phosphate lands mined before July, 1975. Under the
program, landowners submit reclamation plans to the Department of Environmental Protection for
approval, and are reimbursed for approved costs at the completion of the work. Approximately
$8-$10 million are appropriated annually for non-mandatory reclamation. Within the Little
Manatee CWM area, opportunities may exist within the Hillsborough County portion of the
watershed to use such funding.
6.4.4 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 best information available" (373.042, F.S.).
The District proposes to establish minimum flows for the Little Manatee River by the year 2015.
6.4.5 Total Maximum Daily Loads: See Water Quality Chapter.
6.5 LAND USE IMPACTS AND OPPORTUNITIES
Urbanization
Most, if not all, issues related to natural systems within the Little Manatee River watershed are
directly or indirectly related to land development and land use activities. The extent of
urbanization throughout the eastern extent of the watershed has caused widespread changes to
the landscape, as natural lands were cleared and developed. This pattern is particularly noticeable
along the coast and the major corridors (i.e.,US 41, I-75 and US 301) traversing the watershed. In
the long-term, the area is expected to experience continued growth. Hillsborough County’s
housing and population growth is projected to occur in the vicinity of existing urban areas, where
urban support and transportation amenities are in place. Slower growth is anticipated in the
portion of the watershed in northern Manatee County, which maintains a more rural atmosphere.
Urban uses, however, are expanding eastward in Manatee County, from the traditional growth
areas along the coast. In both counties, increased commercial, office and light industrial
development is expected to continue along the major roadway corridors.
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Land development is expected to continue to produce adverse impacts to natural systems as more
natural lands are converted for human functions. The size, condition, distribution and relative
abundance of natural plant communities will be inevitably affected. Reductions in biological
diversity, habitat quality, wildlife abundance and distributions often result. The change also has
implications for water quality. Impermeable surfaces (i.e., roadways, rooftops, and parking lots)
created by urbanization prevent the filtration of runoff prior to flowing into surface waters leading
to declines in water quality. In addition, the use pesticides and fertilizers, commonly associated
with urban development, can cause water quality decline.
In a watershed characterized by growth and development, management becomes extremely
important. The management actions identified by the CWM include protection of remaining
critical habitat through traditional measures such as fee simple acquisition less-than fee and
conservation easements. There is also the need for increased public awareness of ecosystem
issues and management to promote better stewardship. Finally, the area could benefit from
coordinated water and land planning. Such planning would help ensure the quality of our
environment and the sustainability of our water resources.
Agriculture
Agricultural activity within the CWM area is expected to remain at current levels. Agriculture
associated with the area includes citrus, pasture, row crops and aquaculture. The natural systems
issue commonly posed by agriculture is surface water quality. In the Little Manatee River, the
surface water quality ranges from good to fair, with no severe water quality problems reported.
There have been, however, elevated nutrient and bacteria levels detected in the upstream reaches
of the river that are believed to be connected to agriculture. In addition, the river continues to
experience high sediment loadings that may be linked in part to agriculture. Further investigations
are needed to determine the exact cause of the problem and solutions for addressing it.
Agricultural Best Management Practices (BMPs) have been promoted by the agriculture industry
for many years as a means of reducing the water quality impacts that are sometimes attributable
to agriculture. Recently, the University of Florida's Institute of Food and Agricultural Sciences
released a report which documented many of the water quality benefits of present day agricultural
BMPs. Nonetheless, intensive agricultural production continues to represent a significant source
of water quality degradation. Management opportunities for addressing agriculture impacts
should continue to be identified. This is particularly important in the Little Manatee River CWM
area due to the OFW status of Cockroach Bay, Terra Ceia Bay and portions of the Little Manatee
River.
The disposal of plastic sheeting used in row crop operations (e.g., strawberries, tomatoes) is
another issue within the CWM area. This plastic sheeting is used to stabilize beds and reduce
chemical use (e.g., fumigants, pesticides, fertilizers), and can be effective, when combined with
other applications, in reducing water and crop production costs. Disposal of the plastic is
performed, at the end of growing season, by either stockpiling or burning. The problem presented
by current disposal methods is that the plastic is not completely destroyed; tattered pieces of
plastic often make their way into surface waters and flora.
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Key strategies identified by the Team for addressing the plastic problem include improvement of
disposal methods, education on proper disposal and the creation of buffers to reduce direct
transport into waterbodies.
Phosphate
Phosphate has been a major economic force in Central Florida region since the late 1800s. As the
traditional mining areas become depleted, the operations have expanded more and more into
Manatee and Hillsborough counties. Areas within the CWM mined, experiencing mining or
proposed for future mining include the headwaters region of the Little Manatee River along the
North Fork, and in the vicinity of the South Fork in Manatee County.
Phosphate ore is strip mined through the use of draglines. The overburden is removed and
stockpiled; then the ore is removed leaving a “moonscape” of high, steep piles of overburden soil
and phosphate pits which fill with water. This type of mining severely disturbs all aspects of the
landscape in which it occurs. Whatever land use existed prior to mining is completely disrupted
during mining, and is likely to be forever changed.
Phosphate mining, by its very nature, alters the hydrology of the area being mined. Tons of earth
are removed, areas in active mining are dewatered, and, even after reclamation, surface infiltration
and groundwater flow are unlike historic characteristics. During the mining process, mines are
required to retain all surface water runoff onsite. This precludes typical runoff from rain events
that occur within the watershed from entering the tributaries or main stem of the river. This is a
hydrologic alteration resulting in the alteration of periodicity of flow in the river. Periodicity of
flow results in naturally occurring inherent disturbances (i.e., periods of higher flow) within the
aquatic habitat that certain species have evolved to deal with. Elimination of these disturbances
may favor some species over others.
This alteration in flow regime, whether temporary or permanent, alters aquatic habitat.
Depending on how the watershed is reclaimed the alteration may be only temporary, or may well
be permanent. Typically, mined land is reclaimed in a different land form than it was prior to
mining.
In the early 1990’s, DEP and FFWCC developed the Integrated Habitat Network (IHN) as a guide
for the reclamation of mined lands and the enhancement of unmined lands within the southern
phosphate district. With appropriate management, the IHN lands are expected to improve wildlife
habitat, benefit water quality and quantity, and serve as connections between river systems in the
mining region and significant environmental features outside the mining district. Much of this
network system is concentrated in the riverine corridors Little Manatee, Peace and Alafia river
watersheds.
Because of the CWM’s large mining ownership, and the magnitude of the impacts associated with
the industry, successful watershed management depends on sound management practices for
mining. The Team’s recommended approach to addressing the challenges of mining includes
eliminating/reducing impacts to environmentally sensitive areas, development of reclamation
plans for mined areas with an ecosystem management approach, the reestablishment of ground
and surface water flows and the protection of surface waters.
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6.6 ACTION PLAN: NATURAL SYSTEMS
ISSUE #1: HABITAT LOSS, ALTERATION AND FRAGMENTATION
BACKGROUND:
Habitat loss, alteration and fragmentation are the most critical variables threatening the Little
Manatee River watershed ecosystem. Existing and proposed land development (industrial,
agricultural, suburban and urban) throughout the watershed has and will continue to produce
adverse environmental impacts for the area’s ecosystem. Currently, an estimated 38.6% of the
historical ecosystem remains, with 61.4% of the watershed having experienced some form of
development. 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.
Of all the natural systems issues outlined in this management plan, strategies outlined for this
issue are the most important to successfully implement and guarantee the long-term viability of
the watershed’s ecosystem. As noted in the Introduction, this plan is based on “total ecosystem
management” and revolves around several basic steps. In essence, the process involves the
practice of normative forecasting, the process of deciding on what we would like our ecosystem to
be like over the next 100 years and then what steps must be taken to make that future vision a
reality. In short, decisions must be made on how much of the ecosystem we would like to
preserve/restore/manage. These areas should be placed in public ownership and/or overlain with
conservation easements, enhanced/restored, and then properly managed. Proper management of
these resources is critically important for the long-term viability and maximum habitat values of
these areas for wildlife and human utilization. Management of ecosystems must be a dynamic
process, based on reliable monitoring data and evaluations of the effectiveness of management
techniques.
STRATEGY:
Protect remaining natural systems and their functions within the watershed through land
acquisition (fee simple) and other land conservation methods (e.g., less-then-fee acquisition,
conservation easements, land management, etc.). High quality natural areas are a priority,
particularly for establishing and/or maintaining wildlife corridors and areas of high biodiversity and
biological importance. The coordination of all levels of programs (local, state, regional, federal)
striving to implement this strategy is extremely important; coordination is essential to eliminate
redundancy and maximize successful strategy implementation. Some guidance on how to
accomplish this strategy might be garnered from Hillsborough County and their Integrated
Conservation Process (ICP), a program conducted staffed by the Hillsborough County City-County
Planning Commission.
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
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populations often can be directly correlated with sizes and distributions of functional
habitats. As such, habitat protection and restoration acreages should be based on
managed carrying capacity goals (see “habitat restoration” strategy below) complementary
with water quality and water supply 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.
3. In coordination with local, regional and state acquisition programs (e.g., Hillsborough
County ELAPP, Manatee County ELMAC, Preservation 2000, Save Our Rivers, etc.), identify
and prioritize lands targeted for acquisition, inclusive of establishing/maintaining
“greenbelts/green webs” and wildlife corridors. 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 Fish and
Wildlife Conservation Commission’s “Closing the Gaps” report and maps; Florida Natural
Areas Inventory data; Tampa Bay Estuary Program’s “Charting the Course” management
plan and their “Setting Priorities from Tampa Bay Habitat Protection and Restoration:
Restoring the Balance.”
4. Explore, develop and implement alternatives to land acquisition to meet strategic goals of
preserving ecosystem functions within the watershed. These include, among others: 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.); and, 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.
5. Educate private landowners about protection, management, and enhancement/restoration
of habitats and provide assistance as appropriate (inclusive of exotic plant management).
6. Support development of a Manatee County land acquisition and management program.
RESPONSIBLE PARTIES: SWFWMD, FDEP, FFWCC, Hillsborough County, Manatee County
TENTATIVE SCHEDULE: In 2002, initiate coordination needed to implement action items.
EXPECTED BENEFITS: Increased lands in protective status.
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
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preserve 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 the
SWIM program and the TBEP. For purposes of simplification, hereafter any reference to habitat
“restoration” will be synonymous with habitat “enhancement, restoration, and creation.”
ACTIONS:
1. Identify habitat goals for the watershed and coordinate these goals with land acquisition
and management programs; habitat goals should include acreages and distributions of all
coastal habitats necessary to insure viable wildlife populations. 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
research 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 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 post-project management is critical to the
long-term success of the habitat project.
4. Encourage the creation of a permanent funding sources for habitat restoration projects and
management. This funding source would complement local and regional sources.
5. Encourage regional mitigation banks (both public and private) to complement other habitat
restoration projects, where feasible and appropriate.
RESPONSIBLE PARTIES: SWFWMD, FDEP, FFWCC, Hillsborough County, Manatee County,
environmental organizations (e.g., National Audubon, Tampa BAYWATCH, etc.), United States
Fish and Wildlife Service, United States Army Corp of Engineers.
TENTATIVE SCHEDULE: In 2002, initiate coordination needed to implement action items.
EXPECTED BENEFITS: Increased wildlife populations and viable habitats.
The following are major District projects addressing this issue.
Project: Ruskin Inlet Habitat Restoration.
Tampa Bay is the District’s top priority Surface Water Improvement and Management program
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waterbody, a Category I (most in need of restoration) under the State’s Unified Watershed
Assessment and Watershed Restoration Priorities and considered an estuary of national
significance through participation in the National Estuary Program. Since 1950, about 50 percent
of the bay’s natural shoreline and 40 percent of its seagrass acreage were lost as a result of
physical destruction and water quality impairment. This resulted in a decline in the aesthetic,
recreational and commercial value of the bay, as well as a loss of habitat for native plants and
animals. The Ruskin Inlet/Marsh Creek project is a SWIM coastal restoration project in
Hillsborough County. The restoration project will involve invasive plant (e.g., Brazilian Pepper,
Australian Pine) removal, and development of a plan for potential restoration opportunities.
Participants: Alafia River Basin Board, State SWIM, Gardinier Trust.
Status: Proposed.
Project: Cockroach Bay.
This 500-acre project is an ecosystem restoration effort, located in southeastern Tampa Bay on
property owned by Hillsborough County. The 651-acre property was purchased in 1991. Since
purchase, the project has evolved into an ecosystem project, encompassing all habitats typically
found in coastal areas of the bay inclusive of uplands, freshwater and estuarine wetlands and
stormwater treatment of regional agricultural runoff.
Participants: Hillsborough County, State SWIM, Alafia River Basin Board.
Status: Ongoing.
Project: Terra Ceia Isles Habitat Restoration.
The Terra Ceia Aquatic and Buffer Preserves habitat enhancement and restoration project is
located in the southeastern reaches of Tampa Bay. This large, multi-phased project involves 2,308
acres of publicly-owned land (Terra Ceia Isles and Peanut Lake parcel) with an additional 2,900
acres in the District’s five-year acquisition plan. The project involves the enhancement,
restoration and management of various habitats typical of coastal ecosystems, including estuarine
and freshwater wetlands, transitional habitats and uplands.
Participants: State SWIM, Manasota Basin Board, Save Our Rivers, NOAA.
Status: Ongoing.
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ISSUE #2: PUBLIC ACCESS AND RECREATION
BACKGROUND:
Residents and seasonal visitors are attracted to the Little Manatee River watershed (and the
Cockroach Bay and Terra Ceia Aquatic Preserve) because of its aesthetically pleasing
environments, wildlife populations, subtropical climate and water features. As such, recreational
activities are an important attraction for the public. Like all ecosystems, the Little Manatee River
watershed has a carrying capacity for humans which, if exceeded, reduces resident wildlife
populations and habitat values. 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 in 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 recreational types and user demands within the watershed
and project future needs (e.g., boating, fishing, cycling, horseback riding, hiking, camping,
etc.). Coordinate with counties to address a) the level of service for recreational needs and
b) any needs outside of the level of service.
2. Determine existing and projected impacts of various recreational activities within the
ecosystem.
3. Develop management plans for each natural area appropriate for human use, inclusive of
determining carrying capacities of human use. As part of each management plan, establish
public access points to these natural areas, restricting 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/governmental 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). Management plans should be dynamic and regularly
revised to adjust for ecosystem needs.
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 roles the public play
in maintaining the ecosystem. Some educational efforts will need to be site-specific.
RESPONSIBLE PARTIES: SWFWMD, FDEP, FFWCC, Hillsborough County, Manatee County, U.S.
Department of Interior, environmental organizations, public and private school systems.
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TENTATIVE SCHEDULE:
1) Continue to update and circulate the Recreational Guide to Southwest Florida Water
Management District Lands, which identifies the District’s properties and the recreational
opportunities available on them.
2) Coordinate with local governments to increase recreational opportunities on District lands
when appropriate.
EXPECTED BENEFITS: Increased recreational opportunities.
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ISSUE #3: PUBLIC EDUCATION
BACKGROUND:
The destruction and degradation of environmental resources is due, in part, to the public,
scientist, educator and politician’s lack of understanding of the importance and roles that
ecosystems play in their lives. Particularly since the 1960s, there has 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, regulations, and efforts to preserve, protect, restore and manage.
In spite of what progress has been accomplished, much is left to accomplish concerning the
enlightenment of the residents and visitors of 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 to define what roles humans can play in
insuring the future of the region’s natural resources.
STRATEGY:
Coordinate the efforts of environmental agencies, environmental groups and governments to
properly educate the region’s citizenry and visitors of the importance of preserving, restoring and
managing our natural resources and what roles they can play in insuring the future of the region’s
natural resources.
ACTIONS:
1. Insure that public education curricula includes appropriate lessons 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, shoreline
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 regional environmental issues, and
conduct research important for the long-term preservation, restoration, and management
of natural resources.
5. Recognizing that many environmental decisions are made through the political process,
encourage citizens to participate in that process.
6. Encourage 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.).
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RESPONSIBLE PARTIES: SWFWMD, FDEP, FFWCC, Hillsborough and Manatee Counties (inclusive
of public and private school systems), regional colleges/universities, various environmental
organizations.
TENTATIVE SCHEDULE: In 2003, initiate coordination needed to implement action items.
EXPECTED BENEFITS: Increased protection of natural resources.
The following is a major District project addressing this issue.
Project: Public Education.
The annual communications and education program uses various mediums to inform and educate
the public about the importance of managing and protecting the water resources to ensure
healthy, productive and sustainable water resources now and in the future. It supports,
recognizes and connects communities at a grassroots level and it empowers citizens and
communities to join together to take the necessary steps, voluntarily, to protect and preserve our
water resources. Components of the program include a direct mail piece, brochures, information
packets, Internet banners, water trivia contests and other water resource education materials.
Participants: District and all eight Basin Boards.
Status: Ongoing.
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ISSUE #4: URBANIZATION AND AGRICULTURE ENCROACHMENT
BACKGROUND:
Urban development and agriculture have been and are expected to continue to be major forces in
the Little Manatee River watershed. In 1995, urban development consumed about 10% of the
watershed while 63% was used for agricultural uses. Local comprehensive plans implemented
within the watershed suggest that urbanization and agriculture will continue to be significant in
the area. In the case of agriculture, however, the level of activity experienced today is expected to
remain constant. Accordingly, if urban acreage increases and agricultural acreage remains stable,
then natural areas will have to be smaller and/or fewer in number as compared to present
acreages.
STRATEGY:
Manage the encroachment of urban and agricultural development into significant habitat areas.
ACTIONS:
1. Prepare a coordinated and comprehensive land and water linkage study for the area.
Implement strategies recommended by the study.
2. Develop and implement development practices for rural areas.
3. Coordinate land acquisition and other conservation efforts among all available programs
(local, regional, state and federal).
4. Include conservation easements and other less-than fee instruments as methods to secure
protection of natural lands and other resources.
5. Educate private landowners about the benefits of protection and proper management of
habitats.
6. 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.
7. Coordinate with, and, as appropriate, revise Florida Department of Transportation’s plan
and other plans (i.e., comprehensive plans) that propose infrastructure that could have
adverse impacts on the watershed’s ecosystem.
8. Provide more urban green space via parks, preserves, and promotion of property owners
maintaining and/or planting additional native vegetation on their properties.
RESPONSIBLE PARTIES: SWFWMD, Hillsborough County, Hillsborough County City-County
Planning Commission, Tampa Bay Regional Planning Council, FDEP, Manatee County, FFWCC,
stakeholders.
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TENTATIVE SCHEDULE:
1. In 2002, complete contract work on the Hillsborough County/SWFWMD Little Manatee
River Land/Water Linkage initiative.
2. In 2003, initiate implementation activities recommended by the land/water linkage
initiative.
3. In 2002, encourage similar land/water planning in Manatee County.
EXPECTED BENEFITS: Increased protection of important natural areas.
The following is a major District project addressing this issue.
Project: Hillsborough County-Little Manatee River Watershed Plan Land/Water Linkage Project.
The Little Manatee River Land/Water Linkage Project’s goal is to promote citizen and stakeholder
outreach, communication and education. The project accomplishes this through facilitated
workshops with local citizens and stakeholders to identify preferences and priorities for District
and County planning and resource management initiatives. A report entitled “Little Manatee
Land/Water Linkage-Staff Report,” identifying specific strategies, projects and priorities for the
District’s Little Manatee River Comprehensive Watershed Management Plan and the County’s
growth management process, is a product of the project.
Participants: Alafia River Basin Board, Hillsborough County.
Status: Ongoing.
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ISSUE #5: PHOSPHATE MINING AND RECLAMATION ACTIVITIES
BACKGROUND:
Phosphate mining continues to expand outward from the central Florida region into unmined
areas, including portions of the Little Manatee River watershed. Areas mined, experiencing mining
or designated for future mining include the headwaters region of the Little Manatee River along
the North Fork and in the vicinity of the South Fork in Manatee County. Past mining activities
within other watersheds have resulted in major alterations of the riverine ecosystems, and there is
some concern that mining within the Little Manatee watershed may have similar results. Because
we have a good understanding of the potential impacts associated with mining, reducing the
ecological toll of these activities on wildlife habitats and water resources is paramount to
protecting and preserving the health of the Little Manatee River ecosystem.
STRATEGY:
During the mine planning process, eliminate or reduce to the greatest extent, mining impacts to
natural uplands and wetlands providing important wildlife habitat.
ACTIONS:
1. Identify natural riverine corridors, core wildlife habitat areas and buffer areas to be
preserved.
2. Identify environmentally sensitive areas that are not capable of being effectively restored.
3. Restrict mining in habitats known to support species listed as threatened, endangered or of
special concern.
4. Develop incentives to encourage the preservation of viable natural areas.
5. Encourage the use of FDEP’s Non-mandatory Land Reclamation Trust Fund.
6. Support expansions of the IHN system.
RESPONSIBLE PARTIES: FDEP, FFWCC, SWFWMD, Hillsborough County, Environmental
Protection Commission of Hillsborough County, Florida Institute of Phosphate Research, Tampa
Bay Regional Planning Council, DCA.
TENTATIVE SCHEDULE: In 2003, initiate coordination needed to implement action items.
EXPECTED BENEFITS: Increased protection for important natural areas.
STRATEGY:
Develop reclamation plans using a holistic, ecosystem approach that not only restores habitats
lost to mining, but, if possible, provides habitat linkages to natural systems beyond the boundaries
of mined lands.
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ACTIONS:
1. Incorporate greenway and corridor plans into reclamation plans where existing corridors
are proposed as areas to be mined.
2. Develop reclamation plans that create linkages between restored and preserved habitats
to natural systems (corridors and core habitat areas) outside the mining area.
3. Ensure the use of best available technology to restore natural land forms and plant
communities during the reclamation process.
4. Require the preparation of wetland/lake management plans for mined lands reclaimed to
lakes to ensure that such areas become viable and productive aquatic systems.
5. Require the successful reclamation of essential wildlife habitat prior to permitting land
excavations in areas that support listed (endangered, threatened, or species of special
concern) plant or animal species.
RESPONSIBLE PARTIES: FDEP, FFWCC, SWFWMD, Hillsborough County, Hillsborough County
Environmental Protection Commission, Tampa Bay Regional Planning Commission, DCA.
TENTATIVE SCHEDULE: In 2003, initiate coordination needed to implement action items.
EXPECTED BENEFITS: Increased success of reclaimed areas.
STRATEGY:
Reestablish pre-mining surface water flows and patterns from the contributing surface water
basin(s), as well as ground water base flows in the river as a part of the reclamation process.
ACTIONS:
1. Determine pre-mining surface water flows (dry season, wet season and yearly average)
and patterns for contributing surface water basins to be mined.
2. Determine pre-mining ground water base flows (dry season, wet season and yearly
average) from the surrounding aquifers for portions of the river to be mined.
3. Reestablish to greatest extent practicable, the pre-mining surface water flows and patterns
for surface water basins that were mined.
4. Reestablish to the greatest extent practicable, the pre-mining ground water base flows
from the surrounding aquifers for the portion of the river that was mined.
RESPONSIBLE PARTIES: DEP, SWFWMD, Hillsborough County, Hillsborough County
Environmental Protection Commission, Tampa Bay Regional Planning Council, Department of
Community Affairs.
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TENTATIVE SCHEDULE: In 2003, initiate coordination needed to implement action items.
EXPECTED BENEFITS: Increased restoration of natural water patterns.
STRATEGY:
Protect surface water quality of receiving waterbodies during and after mining activities.
ACTIONS:
1. Determine pre-mining water quality conditions within tributaries and/or portions of the
river to be mined.
2. Use Best Management Practices or best available technology to protect surface
waterbodies from water quality degradation during the mining process.
3. Use best available technology to construct impoundments that retain or detain
environmentally toxic or poor quality water.
4. Evaluate and/or update emergency action plans to prevent accidental spills.
RESPONSIBLE PARTIES: FDEP, SWFWMD, Hillsborough County, Environmental Protection
Commission of Hillsborough County, Tampa Bay Regional Planning Council, DCA.
TENTATIVE SCHEDULE: In 2003, initiate coordination needed to implement action items.
EXPECTED BENEFITS: Increased protection of natural surface waterbodies.
LITTLE MANATEE RIVER CWM PLAN
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ISSUE #6: PLASTIC SHEETING
BACKGROUND:
Black plastic sheeting is used extensively in row crop operations (e.g., strawberries, tomatoes)
within the Little Manatee River watershed. The plastic is used to stabilize beds and reduce
chemical use (e.g., fumigants, pesticides, fertilizers). Combined with drip irrigation, the use of
plastic can reduce water use and costs of growing crops. At the end of crop season, plastic is
pulled up and either burned or stockpiled. The plastic cannot be reused. After use, the plastic is
often tattered, resulting in small to large plastic pieces. A portion of this plastic ends up in
tributaries to the Little Manatee River or the river itself. Within the river or the tributaries, the
plastic can be found in trees and shrubs along the banks, along the water edge, or buried in
sediments. The plastic can eventually end up in the estuarine portions of the river before drifting
into Tampa Bay. Aside from aesthetics, a more serious consequence of the plastic is it can
entangle or be consumed by wildlife.
STRATEGY:
Reduce the amount of plastic that litters the river and its tributaries.
ACTIONS:
1. Encourage use of environmentally friendly, biodegradable sheeting materials.
2. Restrict and/or improve techniques for burning or stockpiling plastic so that refuse cannot
enter the area’s waters.
3. Develop and implement educational programs for farmers concerning their use and proper
disposal of plastics. This includes coordination with the Natural Resources Conservation
Service (NRCS) on providing farmers guidance on an optimal irrigation system design and
operating methodology.
4. Continue acquiring property along the river and its tributaries, thereby establishing a buffer
and reducing direct transport of plastic into the river.
5. Include plastic disposal as part of the permitting process. Include plastic disposal in the
“whole farm planning” process.
RESPONSIBLE PARTIES: US Department of Agriculture, Florida Department of Agricultural and
Consumer Services, Hillsborough and Manatee County Agricultural Extension Services,
SWFWMD.
TENTATIVE SCHEDULE: In 2003, initiate coordination needed to implement action items.
EXPECTED BENEFITS: Reduce or eliminate watershed threats posed by sheeting material.
LITTLE MANATEE RIVER CWM PLAN
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ISSUE #7: 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 Little Manatee River watershed.
As noted, the Little 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.
Sub-issue: Agricultural chemical use and runoff. (see “Water Quality” section of this plan)
Sub-issue: 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: Wastewater treatment plants (WWTP) function to remove organic and inorganic solids
from sewage; properly operating facilities (particularly advanced wastewater treatment plants)
produce effluents that have relatively small environmental impacts. While most of the urban areas
of Hillsborough and Manatee Counties are connected to the sewer system, most rural areas use
septic systems to treat wastewater. Discharges from WWTPs and sludge disposal is regulated by
the FDEP under Chapters 62-302, 62-600, 62-650, 62-640, and 64E-6 F.A.C.
The disposal of domestic sludge is primarily accomplished by land-spreading. This activity is
conducted primarily by the agricultural community to enrich their pastures. Until recently, the
activity 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. The ordinance
requires 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').
Another important feature of the ordinance is the requirement of a NRCS Conservation Plan for
land-spreading sites. The is requirement calls for a comprehensive analysis of site, crop and soils.
In addition, residual generators are also required to prepare an Agricultural Use Plan.
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As noted, septic tanks are located mainly in the rural areas of the Little Manatee River watershed.
Septic systems are less efficient in cleansing sewage as compared to wastewater treatment plants,
particularly if the home system is poorly maintained. If soils are highly porous, poorly treated
seepage can reach groundwater, riverine, or estuarine systems potentially polluting these systems
with pathogens, heavy metals and/or nutrients.
Sub-issue: 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 Little 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. 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.
Hillsborough and Manatee counties currently have eight and three air monitoring stations,
respectively, recording ozone, sulphur dioxide, carbon dioxide, nitric oxide, nitrogen dioxide,
particulate matter (PM), PM-10 (particles

quality and habitat in two ways: pollutant loading and quantity of flow. During flood events these
two elements are closely linked. Water quality deteriorates rapidly during a storm event and
pollutants that are not commonly applied to surface waters may enter the waterbodies. Runoff
volumes are often increased because of land development and impervious surfaces. The runoff
can cause erosion of stream banks, transport sediment loads and contribute pollutants to the river
and estuary. Contaminants typically associated with stormwater include sediments, 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, algal 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 Little
Manatee River watershed ecosystem.
STRATEGY (all sub-issues):
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.
RESPONSIBLE PARTIES: U.S. Environmental Protection Agency, Natural Resources Conservation
Service, SWFWMD, FDEP, Manatee County, Hillsborough County.
TENTATIVE SCHEDULE: In 2003, initiate coordination needed to implement action items.
EXPECTED BENEFITS: Reduction in environmental pollutants.
LITTLE MANATEE RIVER CWM PLAN
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The following is a major District project addressing this issue.
Project: Hillsborough County-Lake and Streams Program
This is a continuing program with program goals of 1) monitoring water quality in 120 lakes and
20 streams; 2) training citizen volunteers to collect and measure water quality samples; and, 3)
training lake property owners in lake management techniques and general public education in
water resource and wetland preservation. The initiative also includes entering the data into
Hillsborough County’s Lake Atlas Site, and maintenance of the site and expansion of the lake atlas
into the Hillsborough County Watershed Atlas (which will include rivers and their tributaries).
Participants: Hillsborough County, Alafia River, Hillsborough River and Northwest Hillsborough
Basin Board.
Status: Ongoing.
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ISSUE #8: POLLUTED SITES AND HAZARDOUS WASTES
Sub-issue: 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
administers this program. USEPA 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. The Little Manatee River watershed has no superfund sites.
Petroleum, however, is a pollutant found within the Little Manatee River watershed. The FDEP
manages the Tank Program under F.A.C. Chapter 62-762. 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 Hillsborough County officials and by the Environmental Management
Department of Manatee County.
Sub-issue: The Resource Conservation and Recovery Act gave authority to USEPA to regulate
hazardous wastes (40 CFR Sections 260-271). The Florida Department of Environmental
Protection 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)
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:
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.
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ACTIONS:
1. Require local businesses to assess wastes they produce and handle them with greater care.
2. Provide technical assistance and educational literature to small businesses.
3. Encourage businesses to use alternative, more environmentally friendly products, and, as
feasible, reduce waste and recycle.
4. Educate consumers on the purchase, use, and storage of products.
5. Establish collection events and regular collection sites (e.g., “Amnesty Days” program).
RESPONSIBLE PARTIES: U.S. Environmental Protection Agency, FDEP, Manatee County,
Hillsborough County, City of Palmetto, Tampa Bay Regional Planning Council, SWFWMD.
TENTATIVE SCHEDULE:
1. Coordinate with responsible parties on ways to address threats posed to the CWM area by
hazardous wastes in 2003.
2. Include in District publications, when appropriate, information on threats posed to water
resources by hazardous waste.
EXPECTED BENEFITS: Minimize or eliminate the threat posed by hazardous waste in the
watershed.
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