--FINAL--
THE LAKE TARPON DRAINAGE BASIN
MANAGEMENT PLAN
Prepared For:
Pinellas County
Board of County Commissioners
440 Court Street
Clearwater, FL 33756
Prepared By:
Coastal Environmental/PBS&J, Inc.
5300 West Cypress Street, Suite 300
Tampa, FL 33607
October 1998
ACKNOWLEDGMENTS
The primary authors of this document are Mr. Douglas Robison (Project Manager), and Mr. Hans Zarbock (Project Engineer). Significant technical contributions to this work were provided by Mr. David Wade, Dr. Raymond Pribble, Dr. Anthony Janicki, Mr. Andrew Squires, Mr. Stephen Peacock, Ms. Guo Cheng, Ms. Melisa Reiter, Ms. Susan Janicki, Ms. Trudy Killeen and Ms. Tammy Lyons. In addition, significant editorial and document production contributions were provided by Ms. Candace Daniel throughout the project duration.
Express thanks go to Ms. Pamela Leasure, Mr. Will Davis, Dr. Thomas Cuba, Mr. Donald Moores and Mr. Andrew Squires for their perseverance throughout the planning process, and for their steadfast dedication to the betterment of Lake Tarpon. Additional thanks go to Dr. Marty Kelly for his technical guidance and wisdom, his relentless sense of humor, and for continuously challenging all of us to seek the truth.
Finally, special mention should also be given to all members of the Lake Tarpon Management Committee for their faithful service and personal commitment to the protection and improvement of Lake Tarpon over the past decade. In particular, Mr. Tom Champeau, Mr. Bob Weindel, Mr. Jerry Browne and Mr. Stacy Beyer were instrumental in the development of the Plan.
TABLE OF CONTENTS
Section Page
Acknowledgments i
List of Figures v
List of Tables vii
List of Acronyms ix
Executive Summary ES-1
1.0 Introduction 1-1
1.1 Project Background 1-1
1.2 Purpose and Objectives of the Plan 1-4
1.3 Plan Organization 1-5
2.0 Summary of Existing Conditions 2-1
2.1 Priority Lake and Watershed Management Issues 2-1
2.2 Water Quality 2-3
2.2.1 Status and Trends 2-5
2.2.2 Pollutant Loading Sources 2-12
2.3 Aquatic Vegetation 2-22
2.3.1 Submerged Aquatic Vegetation 2-22
2.3.2 Emergent Aquatic Vegetation 2-25
2.4 Fisheries 2-26
2.5 Wildlife and Associated Habitat 2-30
2.5.1 Watershed Habitats 2-30
2.5.2 Wildlife Utilization 2-36
2.6 Flood Control 2-39
2.7 Recreation and Aesthetics 2-42
2.7.1 Recreational User Conflicts 2-42
2.7.2 Enforcement 2-44
2.7.3 Aesthetics 2-45
2.8 Public Education 2-46
3.0 Alternatives Analysis 3-1
3.1 Development of BMP Alternatives 3-1
3.1.1 Potential Reduction of Internal Nutrient Loads 3-1
3.1.2 Potential Reduction of External Nutrient Loads 3-2
3.2 Cost-Effectiveness Analysis of Plan Alternatives 3-3
3.2.1 Conversion of Septic Tanks to Sanitary Sewer Service 3-4
3.2.2 Stormwater Rehabilitation with Wet Detention Ponds 3-8
3.2.3 Stormwater Rehabilitation with Alum Injection 3-11
3.2.4 Cost-Effectiveness Comparison 3-14
3.3 Attainable Benefits of Load Reduction Strategies 3-17
3.3.1 Internal Load Reductions 3-17
3.3.2 External Load Reductions 3-19
3.3.3 Water Quality Impacts of Load Reduction Alternatives 3-19
4.0 The Plan 4-1
4.1 Management Goals and Level of Service Targets 4-1
4.1.1 Water Quality 4-1
4.1.2 Aquatic Vegetation 4-4
4.1.3 Fisheries 4-6
4.1.4 Wildlife and Associated Habitat 4-8
4.1.5 Flood Control 4-11
4.1.6 Recreation and Aesthetics 4-11
4.1.7 Public Education 4-13
4.2 Structural Components 4-17
4.3 Management Components 4-32
4.4 Legal Components 4-55
4.5 Policy Components 4-62
4.6 Compliance and Enforcement Components 4-65
4.7 Social and Recreational Components 4-69
4.8 Public Education Components 4-76
4.9 Operation and Maintenance Components 4-80
4.10 Summary of Plan Components 4-81
5.0 Monitoring and Success Evaluation 5-1
5.1 Purpose and Importance of Monitoring 5-1
5.2 Development of Monitoring Objectives 5-2
5.2.1 Water Quality 5-3
5.2.2 Aquatic Vegetation 5-9
5.2.3 Fisheries 5-11
5.2.4 Wildlife and Associated Habitat 5-14
5.2.5 Flood Control 5-16
5.2.6 Recreation and Aesthetics 5-17
5.2.7 Public Education 5-19
5.3 Summary of Recommended Monitoring Program 5-21
6.0 Capital Improvement and Implementation Schedule 6-1
7.0 Financing Requirements and Options 7-1
7.1 Funding Requirements 7-1
7.2 Funding Options 7-1
8.0 References 8-1
9.0 Comments Received on Draft Plan 9-1
LIST OF FIGURES
Figure Page
2-1 Natural eutrophication versus cultural eutrophication 2-4
2-2 Plot of mean annual chlorophyll-a concentrations vs. mean annual TN concentration, with cumulative annual rainfall, for the period 1988-1996. 2-7
2-3 Plot of mean annual chlorophyll-a concentrations against mean annual pH values, with cumulative annual rainfall, for the period 1988-1996. 2-8
2-4 Plots of mean annual chlorophyll-a concentrations vs. mean annual
total nitrogen concentrations for the period 1988-1996. 2-9
2-5 Plots of mean annual chlorophyll-a concentrations vs. mean annual pH
values for the period 1988-1996. 2-10
2-6 Graphical depiction of the water and nutrient budget equations 2-14
2-7 Lake Tarpon sub-basin delineation 2-16
2-8 Plot of mean annual chlorophyll-a concentrations vs. cumulative
total area of hydrilla chemical treatment for the period 1988-1996 2-24
2-9 Fish biomass from shoreline blocknets in Lake Tarpon, 1970-1995 2-28
2-10 Fish community balance in Lake Tarpon, 1970-1995 2-29
2-11 Lake Tarpon drainage basin habitat distribution and recommended
special management areas. 2-31
2-12 Differences in habitat distribution between the east and west sides
of the Lake Tarpon basin 2-33
2-13 Differences in habitat disturbance level between the east and west sides
of the Lake Tarpon basin 2-34
3-1 Plot of total annual external TN load vs. mean annual chlorophyll-a
concentrations in Lake Tarpon for the period 1988-1992 3-21
3-2 Plot of total annual external TP load vs. mean annual chlorophyll-a
concentrations in Lake Tarpon for the period 1988-1992 3-22
3-3 Schematic of the Lake Tarpon box-model 3-24
3-4 Groundwater hydrologic loading to Lake Tarpon as a function of lake
level (from Upchurch, 1998) 3-26
4-1 Priority sub-basins for removal of OWTS (septic tanks) and provision
of central sewer service in the Lake Tarpon basin. 4-20
4-2 Priority sub-basins and manageable hydrologic units (MHUs) for the
provision of enhanced regional stormwater treatment facilities in
the Lake Tarpon basin.. 4-24
4-3 Existing lake level fluctuation schedule adopted for Lake Tarpon 4-37
4-4 Recommended four-year enhanced lake level fluctuation schedule. 4-38
4-5 Potential segmented management scheme for recreational uses on Lake Tarpon:
Option 1 4-72
4-6 Potential segmented management scheme for recreational uses on Lake Tarpon:
Option 2 4-73
LIST OF TABLES
Table Page
2-1 Lake Tarpon annual water budget 2-17
2-2 Lake Tarpon annual total nitrogen budget 2-18
2-3 Lake Tarpon annual total phosphorus budget 2-19
2-4 Summary of the annual economic impact of Lake Tarpon 2-46
3-1 Summary of modeled loads from the priority MHUs and individual sub-basins 3-9
3-2 Comparison of Best Management Practices with respect to relative
cost-effectiveness for TN and TP removal 3-15
3-3 Summary of the TN and TP load reduction potential, unit costs and total
costs of the two primary external and internal load reduction alternatives 3-16
3-4 Total annual TN and TP loadings to Lake Tarpon for the Period 1998-1992
(units in tons/year) 3-20
3-5 Results of box-model simulations of load reduction management actions 3-27
4-1 Summary of adopted goals and recommended targets for each of the
priority lake and watershed management issues 4-15
4-2 Total annual elevational drawdown, total annual drawdown volume, and annualized
potential daily reuse volume for each of the three proposed fluctuation schedules. 4-29
4-3 Tabular summary of target monthly lake levels under the proposed modified
lake level fluctuation schedule. Shaded rows indicate the months during
which the three schedules differ. 4-39
4-4 Summary of estimated annual operation and maintenance costs rounded
to the nearest $1,000 dollars 4-80
5-1 Goals, targets and monitoring objectives for the Water Quality issue 5-8
5-2 Goals, targets and monitoring objectives for the Aquatic Vegetation issue 5-11
5-3 Goals, targets and monitoring objectives for the Fisheries issue 5-13
5-4 Goals, targets and monitoring objectives for the Wildlife and Associated
Habitat issue 5-16
5-5 Goals, targets and monitoring objectives for the Flood Control issue 5-17
5-6 Goals, targets and monitoring objectives for the Recreation and Aesthetics issue 5-19
5-7 Goals, targets and monitoring objectives for the Public Education issue 5-20
5-8 Summary of recommended monitoring program elements 5-24
6-1 Summary of recommended management components of the Lake Tarpon Drainage
Basin Management Plan, and the proposed implementation schedule for each 6-2
7-1 Summary of costs for implementing the recommended Lake Tarpon
Drainage Basin Management Plan. 7-1
7-2 Summary of recommended management components of the Lake Tarpon
Drainage Basin Management Plan, and potential funding sources for each 7-3
LIST OF ACRONYMS
ACOE U.S. Army Corps of Engineers
AWT Advanced Wastewater Treatment
BMPs Best Management Practices
C & R Catch and Release
cfs Cubic Feet per Second
Chl-a Chlorophyll-a
CIP Capital Improvement Project
DO Dissolved Oxygen
EAV Emergent Aquatic Vegetation
EPA Environmental Protection Agency
F/C Forage Fish to Carnivorous Fish Ration
FCES Florida Cooperative Extension Service
FDEP Florida Department of Environmental Protection
FGFWFC Florida Game and Fresh Water Fish Commission
FLUCCS Florida Land Use Cover and Classification System
LT/HIP Lake Tarpon Habitat Improvement Program
LTMC Lake Tarpon Management Committee
mgd Million Gallons per Day
MHUs Manageable Hydrologic Units
MSSW Management and Storage of Surface Waters
MSTU Municipal Service Taxing Unit
NGVD National Geodetic Vertical Datum
O & M Operation and Maintenance
OFW Outstanding Florida Waters
OWTS On-site Wastewater Treatment Systems (septic tanks)
PCDEM Pinellas County Department of Environmental Management
PCMC Pinellas County Mosquito Control
Plan Lake Tarpon Drainage Basin Management Plan
SAV Submerged Aquatic Vegetation
SD Secchi Depth
SMAs Special Management Areas
SOLID Save Our Lakes Invite Discussion
SWFWMD Southwest Florida Water Management District
SWIM Surface Water Improvement and Management
TN Total Nitrogen
TP Total Phosphorus
TSI Trophic State Index
TSS Total Suspended Solids
USFWS U.S. Fish and Wildlife Service
WO Lake Tarpon Watershed Overlay
WWTP Wastewater Treatment Plant