MAY 1991 - University of South Florida County... · 2010-11-29 · 3.1.4 Kissimmee River 3.1.5 St. Johns River Hydrologic Boundaries ... o There are a few drainage complaints throughout

LAKE COUNTY

STORMWATER MANAGEMENT NEEDS ASSESSMENT

FINAL

Prepared by Camp Dresser & McKee Inc.

MAY 1991

environmental engineers, scientists, planners, & rnonogernent cmsultonts

c-. M..

LAKE COUNTY, FLORIDA

STORMWATER MANAGEMENT NEEDS ASSESSMENT

FINAL REPORT

CAMP DRESSER & McKEE INC.

MAY 1991

CONTENTS

Section Page

1.0 INTRODUCTION 1-1

1.1 Background 1.2 Report Purposes and Contents

2.0 DATA SOURCES 2-1

Lake County Neighboring Counties Participating Cities and Towns Non-Participating Cities Lake County Water Authority (LCtJA) United States Geological Survey (USGS) United States Army Corps of Engineers (USACOE) United States Department of Agriculture Soil Conservation Service (USDA-SCS) Federal Emergency Management Agency ( F m ) National Climatic Data Center (NCDC) St. Johns River Water Management District (SJRWMD) Southwest Florida Water Management District (SWFWMD) Florida Department of Environmental Regulation (FDER) Florida Department of Transportation (FDOT) Florida Department of Community Affairs (DCA)

3.0 HYDR0UX;IC AND HYDRAULIC BACKGROUND 3-1

Major Basins 3.1.1 Oklawaha River 3.1.2 Withlacoochee River 3.1.3 Wekiva River 3.1.4 Kissimmee River 3.1.5 St. Johns River Hydrologic Boundaries Topography Aerial Photography Soils Rainfall Stage and Discharge Floodplains and Floodways Land Use and Growth Trends Regional Aquifer Characteristics Inventory of Major Stomter Conveyance Structures

4.0 STORMWATER MANAGEMENT REGULATIONS 4-1

4.1 Lake County 4.2 Cities and Towns 4.3 Federal and State

CONTENTS (contents)

Section

5.0 WATER QUALITY

5.1 General 5.2 Best Management Practices (BMPs)

5.2.1 Structural BMP Alternatives 5.2.2 Comparison of Structural BMPs 5.2.3 Design Criteria for Preferred Structural

BMPS 5.2.4 Pollutant Removal Efficiencies

5.3 Regional vs. Onsite Deployment of Structural BMPs 5.4 Water Quality Evaluations

5.4.1 Existing Lake County Monitoring 5.4.2 Trophic State Index 5.4.3 Stormwater Pollutant Loadings 5.4.4 Failing Septic Tank Impacts 5.4.5 Average Annual Non-Point Pollution Loads

5.5 Summary

6.0 PROBLEM AREAS

6.1 General 6.1.1 Water Quantity (Flooding) 6.1.2 Water Quality

6.2 Problem Area Identification and Evaluations 6.2.1 Water Quantity Problem Areas 6.2.2 Water Quality Problem Areas 6.2.3 Non-Problem Facilities

7.0 COMPUTER MODEL COMPARISONS

7.1 Water Quantity Models 7.1.1 Water Quantity Model Comparison Items 7.1.2 Available Water Quantity Models 7.1.3 Water Quantity Model Recommendations

7.2 Water Quality Models

8.0 LEVELS OF SEKVICE

8.1 Water Quantity 8.2 Water Quality 8.3 Summary 8.4 Prioritization

Page

5-1

CONTENTS (continued)

Section X e

9.1 on-Structural Improvements 9.1.1 Goals, Objectives, and Policies 9.1.2 Stormwater Management Regulations and

Ordinances 9.1.3 Maintenance Practices

9.2 Structural Improvements 9.2.1 Problem Area Improvements 9.2.2 Unknown Problem Area Improvements 9.2.3 Additional Stormwater Management Program

Needs 9.3 Prioritization 9.4 Additional Program Needs

APPENDICES

APPENDIX A - LAKE COUNTY'S STORMKATER SUB-ELEMENT, CHAPTER V1-C, OF THE COUNTY'S COMPREHENSIVE PLAN

APPENDIX B - DATA o Hydrologic Boundary Map o Stormwater Facility Inventory by SubBasin o Soils by Sub-Basin o Land Use by Sub-Basin

APPENDIX C - DRAFT STORMNRTER MANAG- ORDINANCE

(Provided to Lake County under separate cover)

iii

LIST OF TABLES

Table Page

Design Storms Recommendations for the Major Basins Rainfall Summary for Lake County Area, Florida Estimated Water Quality Based on Historic Storms USGS Lake Gages in the Study Area USGS Stream Gages in the Study Area USGS Well Gages in the Study Area Imperviousness by Land Use Category CDM vs. County Land Use Categories

Monitored Wet Detention Basin Efficiencies Total-P and Dissolved P Summary

Summary of Lake Water Quality Monitoring Data Sumrnary of Lake County Trophic State Index Analysis Summary of Lake County Land Use and Hydrological Soils Group

Comparison of Average Annual Total-P Loading Factors for Urban Land Uses: Occoquan Watershed Monitoring Study vs. NURP National Statistics

Summary of Non-Point Pollution Loading Factors by Hydrologic Soils Group

Event Mean Concentrations for the Orlando Metro Areawide Water Quality Study (ECFRPC, 1978)

Event Mean Concentrations and Impervious Percentages for the Tampa Bay Study (CDM, 1984)

Event Mean Concentrations and Impervious Percentages for the Manatee County Southeast Area Study (CDM, 1985)

Water Quantity Problem Areas by Sub-Basin Water Quality Problem Areas by Sub-Basin

Water Quantity Model Sceening Matrix

Recommended Maintenance Frequencies by Facility Type Annual Maintenance Costs Problem Area Summary Conceptual Probable Costs for Retrofit Treatment Facilities

Lake County Stomwater Master Plan Basin Studies Cost Estimate

Priorities for Stormwater Master Planning by Basin Stomwater Management Program Probable Cost Summary

LIST OF FIGURES

Fiaure

Major Basins Detailed Topographic Coverage Generalized SCS Soils Mean Annual, 24-Hour Maximum Rainfall for Northeast Florida, Inches

10-Year, 24-Hour Maximum Rainfall for Northeast Florida, Inches

25-Year, 24-Hour Maximum Rainfall for Northeast Florida, Inches 100-Year, 24-Hour Maximum Rainfall for Northeast Florida, Inches

25-Year, 96-Hour Maximum Rainfall for Northeast Florida, Inches

Rainfall Gages Adapted from SJRWMD TP-88 USGS Lake Gages USGS Stream Gages High Growth Areas Groundwater Characteristics

Wet Detention Basin Settling Curves Onsite vs. Regional BMPs Typical Multi-Purpose Facility Typical Swale Mean Concentration 1985-1990: Total-P Mean Concentration 1985-1990: Total-N Mean Concentration 1985-1990: Secchi Mean Concentration 1985-1990: CHL-A Average Annual Load: Total-P Average Annual Load: Total-N Average Annual Load: Lead Average Annual Load: Zinc Average Annual "Per Acre" Load: Total-P Average Annual "Per Acre" Load: Total-N Average Annual "Per Acre" Load: Lead Average Annual "Per Acre" Load: Zinc

Water Quantity Problem Areas by Sub-Basin Water Quality Problem Areas by Sub-Basin

Water Quantity Levels of Service Water Quality Levels of Service

Following Page

1.0 INTRODUCTION

1.1 BACKGROUND

In May 1990, Lake County initiated a phased Stormwater Management Program

(SWMP) to manage surface and groundwater resources in the County. Camp Dresser & McKee Inc. was selected to perform services related to this

program. The main purposes of the County's overall Stormwater Management

Program are identified as the following:

1. Build a stormwater management system data-base and information

management system which will inventory, locate and describe

existing stormwater management systems, hydrologic basins, and

other related hydrologic parameters in Lake County.

2. Evaluate existing stormwater management system ordinances,

maintenance conditions, and practices.

3. Develop and apply a stormwater management computer model to

simulate stormwater runoff of various frequencies under existing

and future planned land use conditions.

4. Analyze the capability of the existing stormwater system to

accommodate present and future stormwater flows.

5. Assess the magnitude of existing and anticipated future stormwater

problems within the County and prioritize those problems relative

to their need for attention.

6. Establish desired level of service criteria for the various

components of the stormwater management system.

7. Evaluate alternative management plans to meet the desired service

level based on existing and future anticipated deficiencies

identified through data collection and modeling.

8. Develop cost estimates for needed improvements.

9. Develop a Stormwater Management System Capital Improvement Plan

based on identified system improvement needs and a prioritized

implementation schedule.

10. Identify and, if required, develop alternative funding

methodologies, including a stormwater utility, necessary to fund

stormwater management system capital improvements, operations and

maintenance and administration.

11. Meet the planning requirements of the Stormwater Sub-Element of

Chapter 95-5, Florida Administrative Code (FAC).

1.2 REPORT PURPOSES AND CONTENTS

This report presents results from Tasks 1 and 2 of the SWMP: Data

Collection and Preliminary Needs Assessment. Within these two tasks, the foundation for completing the 11 overall purposes of the SWMP has been

formed. For this report, stormwater-related data were collected, evaluated

for adequacy and quality, and utilized to establish levels of detail and

priorities for subsequent SWMP tasks. In addition, conceptual Capital

Improvement Program (CIP) probable cost estimates were made for facilities

to mitigate known stormwater quantity problems, and to provide for the

treatment of stormwater in areas where such facilities do not exist. This

report also presents the recommended levels of service and detail to meet

the requirements of Chapter 95-5, FAC, and the additional future tasks

which will be required for Lake County to complete the overall Stormwater

Management Program objectives.

2.0 DATA SOURCES

Presented below is a summary of the numerous entities and agencies which

retain the stomter data and previous reports pertinent to the Lake

County stomter management system. These entities and agencies were

contacted to obtain or reference existing data and previous reports. The

pertinent data and reports are referenced by the respective entity which

retains them.

LAKE COUNTY

Departments within the Lake County government infrastructure were contacted

to evaluate and document the County's stormwater management resources and

existing data and reports.

The information provided by Lake County personnel is presented below:

o Maps showing municipality boundaries, roadways, lakes, canals, and

bridges at scales of lV=1 mile and 1"=2 miles;

o Map showing the delineation of maintenance district boundaries at

a scale of 1"=1 mile;

o The Lake County Township Book (34 maps) published in 1976 and

revised in 1990, showing municipality boundaries, roadways, lakes,

and canals at a scale of 1"=200OP;

o The Lake County Drainage Atlas developed as part of the Lake

County Comprehensive Plan Drainage Element published in 1976.

Consisting of 29 USGS 7.5 minute quadrangle maps with overlays at

a scale of 1"=2000t, the Atlas shows municipality and hydrologic basin boundaries, existing facilities, flood prone areas,

roadways, lakes, canals, and topographic features;

o The State of Florida Department of Transportation (FDOT) General

Highway Maps for Lake County published in May, 1979.

Municipality, boundaries, roadways, lakes, and canals are shown at

a scale of 1"=2 miles;

o The Lake County subdivision regulations as amended in 1988. This

document establishes design standards for the development of

subdivisions;

o The Lake County Comprehensive Plan published in 1980 was obtained

from the Lake County Planning Department;

o Identification of stormwater-related problem areas in the County;

o Septic Tank Water Quality Impact Study, July 1982, Lake County

Department of Pollution Control;

o Water quality data in digital form for sampling stations and map

showing locations was obtained from the Lake County Department of

Pollution Control;

o Residential and Seasonal Population Estimates and Projections for

Lake County, Florida, 1980-2005, Lake County Planning Department,

December, 1989;

o Index to Lakes by Name and Location, Lake County, Florida, Lake

County Planning Department; and

o Index to Class I11 - A Lakes by Name and Location, Lake County, Florida, Lake County Planning Department.

2.2 NEIGHBORING COUNTIES

The Counties of Marion, Orange, Osceola, Polk, Seminole, Sumter, and

Volusia share Lake County's border. Personnel were contacted in each of

these counties to ascertain pertinent stormwater data and reports related

to Lake County's stormwater management system. Some counties are currently

in the process of formulating their own stormwater programs and/or did not

have pertinent data and thus could not provide the requested information.

The information which was received from the neighboring counties is

presented below.

o Data for Drainage Analysis Units (DAU1s) 1 and 2 (the Palatlakaha

and Withlacoochee Rivers, respectively) from the Polk County

Surface Water Management District were obtained. The DAU1s

contain pervious curve numbers for each sub-basin, and minor basin

as well as sub-basin location maps, land cover area data, percent

impervious surface, and FEMA 100 year floodplain maps.

o There are a few drainage complaints throughout the Wekiva River

Basin which are maintenance related, or due to lack of a drainage

system, resulting in localized flooding in Seminole County.

Construction plans, drainage calculations for developments, and

topographic-aerials, are available throughout the Seminole County

portion of this basin, but these data do not appear to affect

systems in Lake County.

As Lake County progresses with its stormwater management program further

coordination with the neighboring counties will be required to assure that

each county's stormwater management program is properly integrated with

Lake County's.

2.3 PARTICIPATING CITIES AND TOWNS

The following cities and towns are contributing to the funding of the Lake

County Stomwater Management Program:

o Astatula

o Fruitland Park

o Groveland

o Howey-in-the-Hills

o Lady Lake

o Mascotte

o Minneola

o Monteverde

o Umatilla

Personnel within each of the cities and towns were contacted to ascertain

the merits of their existing stormwater management ordinances, the

frequency of maintenance operations for their stormwater facilities, the

availability of pertinent stormwater data and reports, and the

identification of stormwater problems. A summary of this information

provided by the participating cities and towns is presented below.

STORMWATER MANAGEMENT ORDINANCES

The information pertaining to the Stormwater Management Ordinances for the

cities and towns of Lake County is presented in Section 4.0 of this report.

STORMWATER FACILITIES MAINTENANCE

Personnel from each city and town indicated that they have no set

stormwater facility maintenance practices. Maintenance is provided within

each city and town by city or town maintenance crews, along with county

maintenance crews, on an as-needed basis. Thus maintenance is usually

performed in a reactionary mode of operation (i.e., to alleviate a known

problem) versus a preventive mode.

AVAILABLE DATA AND REPORTS

Personnel from each city and town reported that they did not have records

pertinent for stormwater hydrology, hydraulic, and water quality data. The personnel suggested that Lake County, the Lake County Water Authority

(LCWA), or the state and federal agencies be contacted for such information.

PROBLEM AREA IDENTIFICATION

Problem areas were identified within the Cities of Groveland, Mascotte,

Minneola, and Umatilla. No problem areas were identified within the Towns

of Lake County. Further discussion of the problem areas is presented in

Section 6.0 of this report.

2.4 NON-PARTICIPATING CITIES

Five other cities located within Lake County, which are not participating

with the funding of the Lake County Stomwater Management Project were

contacted for the same data requested of the participating cities and

towns. A copy of the subdivision ordinances were obtained during follow-up

visits by CDM. A summary of the stomwater management design standards

contained in the subdivision ordinances is presented in Section 4.0 of this

report. The responses to this request for information are presented below

for each city.

CITY OF CLEZMONT

Several attempts were made to contact City of Clermont personnel regarding

the forwarding of pertinent hydrologic, hydraulic, water quality, problem

area, stomwater maintenance, and stormwater ordinance. However, the

requested data has not been forwarded by the City. Coordination with the

City of Clermont will be required as the County proceeds with future phases

of its Stomter Management Program.

CITY OF EUSTIS

Several attempts were made to contact City of Eustis personnel regarding


area, stomwater maintenance, and stormwater ordinance data. The City's

civil engineering consultant forwarded a map of the City showing problem

area locations to CDM. Coordination with the City of Eustis will be

required as the County proceeds with future phases of its Stormwater

Management Program.

CITY OF LEESBURG

City personnel indicated that much of the information requested (basic

hydrologic, hydraulic, and water quality data for the City; water quantity

and quality problem area records; and maintenance records/practices for

stormwater facilities) has not been documented by the City or it is

available at the County level. A map indicating areas of known flooding

problems was forwarded. There are no written records of water quality data

available. A cow of relevant design criteria utilized since the early

1980's was also included. The City referred to the FDER, SJRWMI), and LCWA

for water quality data. The City was conducting their first drainage study

for a small basin in the northwest area of the City. This study is nearing

completion.

CITY OF MOUNT DORA

The City of Mount Dora is currently beginning its own stormwater program.

Thus the requested data is not presently available. Information acquired

during the development of the City's stormwater plan will be available for

use in developing the future phases of the Lake County Stormwater

Management Program.

CITY OF TAVARES

Several attempts were made to contact City of Tavares personnel regarding


area, stormwater maintenance, and stormter ordinance data. However, the

requested data has not been forwarded by the City. Coordination with the

City of Tavares will be required as the County proceeds with future phases

of its Stormwater Management Program.

2.5 LAKE COUNTY WATER AUTHORITY ( LCWA)

Recognizing the vital role that healthy lakes and rivers play in the

economy and quality of life in Lake County, the Florida Legislature

established in 1953, the Lake County Water Authority (LCWA), formally known

as the Oklawaha Basin Recreation and Water Conservation and Control

~uthority of Lake County.

The following publications and data were provided by LCWA:

o Digital rainfall data for the Eustis, Deland, Sanford, Bushnell,

Inverness, Orlando, Ocala, and Lake Alfred gages;

o Copies of the Lake County Drainage Atlas hydrologic boundaries (at

1:24,000 and 1:100,000 scales);

o State plane coordinate references for USGS 1:24,000 quadrangle

corner points for use in AutoCAD mapping;

o Key map for the LCWA topographic aerial maps. These are 1"=200t

scale, 1-foot contour maps with 1987 photogrammetry. These maps will be acquired as necessary for the master plan;

o Converted 1986 land use from ERRAS format (from ECFRPC) into

ARCH-INFO fo-t;

o Identification of specific problem areas in the County such as

Wolf Branch sink; and

o updates on the ongoing Upper Palatlakaha River Study by

Environmental Science and Engineering (ESE).

The following stormwater-related publications are available in the LCMAfs

library:

o Water and Related Land Resources Florida West Coast Tributaries,

United States Department of Agriculture, in cooperation with the

Division of Water Resources and Conservation Florida State Board

of Conservation, 1965;

o The Green Swamp Project Executive Report Resource Management

Department, Southwest Florida Water Management District, January

1985;

o Hydrology of Lake County, Florida, U.S. Geological Survey Water

Resources Investigation 76-72, August 1976;

o Work Plan for Palatlakaha River Watershed - Lake County, Florida, Oklawaha Basin Recreation and Water Conservation and Control

Authority, Lake Soil Conservation District, Assisted by United States Department of Agriculture, Soil Conservation Survey, August

1965;

o Information Circular No. 40 Mapo Showirig Depths of Selected Lakes

in Florida, Prepared by U.S. Geological Survey in cooperation with

the Trustees of the Internal Improvement Fund of the State of

Florida, Tallahassee, 1964;

o Fish Management Annual Progress Report, Florida Game and Fresh

Water Fish Commission Central Region, 1986-89;

o Water Withdrawals, Use, and Trends in the SJRWMD, St. Johns River

Water Management District, August 1988;

o Map Showing Depths of Selected Lakes in Florida, U.S. Geological

Survey in cooperation with the Trustees of the Internal

Improvement Fund of the State of Florida, 1964;

o Fish Management Annual Progress Report, Florida Game and Fresh

Water Fish Commission, Central Region, 1986 - 1989;

o Water Withdrawals, Use, and Trends in the SJRWm, St. Johns River

Water Management District, Palatka, Florida, 1986;

o List of Publications, Florida Department of Natural Resources,

Division of Resource Management, Bureau of Geology, Tallahassee,

Florida, 1984;

o Proposed Scope of Work for the Lake Apopka Pilot Project, St.

Johns River Water Management District, February 25, 1986;

o Rainfall Analysis for Northeast Florida - Part I: 24-Hour to

10-Day Maximum Rainfall Data, St. Johns River Water Management

District, July 1986;

o Save Our Rivers Five-Year Land Acquisition and Management Plan,

St. Johns River Water Management District, Palatka, Florida,

December 13, 1988;

o Florida: Groundwater Resources National Water Summary, U.S.

Geological Survey;

o Orlando Metropolitan 208 Study: Stomwater Management Practices

Evaluations, East Central Florida Regional Planning Council, July

1979;

o The Green Swamp Project: Environmental Report, Southwest Florida

Water Management District, Resource Management Dept., January

1985;

o The Green Swamp Project: Economic Report, Southwest Florida Water

Management District, September 1984;

o Inspection Report Oklawaha Basin Recreation and Water Conservation

and Control Authority, Gee & Jenson, Consulting Engineers, Inc.,

September 1974;

o Draft Report for the Palatlakaha River Basin, Florida Draft,

Volume 1, Seaburn and Robertson, Inc., Water Resources

Consultants, January 1981;

o Hydrologic Data from A 2,000-Foot Deep Core Hole at Polk City,

Green Swamp Area, Central Florida, U.S. Geological Survey Water

Resources Investigations Report 84-4257, Prepared in cooperation

with City of Cape Coral, Tallahassee, Florida, 1986;

o Summary of Findings on Water Management Needs of Southwest

Florida, Florida Department of Water Resources, Tallahassee,

Florida, May 1961;

o Floodplain Study of the Hicks, Ditch Basin in Lake County,

Florida, St. Johns River Water Management District, Palatka,

Florida, 1990;

o Vertical Recovery Sheets (Survey Control Data) Lake County,

Florida, Auman, Dray, West and Associates, Orlando, Florida;

o Revised Available Data Report Palatlakaha River Basin, Florida

Volume 6 U.S. Army Corps of Engineers, Jacksonville District,

Seaburn and Robertson, Inc., Water Resources Consultants, June

1981 ;

o Evaluation of Water Resources Palatlakaha River Basin, Florida

U.S. Army Corps of Engineers Jacksonville District, Seaburn and

Robertson, Inc., Water Resources Consultants, June 1981;

o Available Data Report for the Palatlakaha River Basin, Florida


Robertson, Inc., Water Resources Consultants, December 1980;

o Draft Report for the Palatlakaha River Basin, Florida Volume 2


Robertson, Inc., Water Resources Consultants, January 1981;

o Evaluation of Water Resources - Phase I1 Palatlakaha River Basin,

Florida U.S. Army Corps of Engineers Jacksonville District,

Seaburn and Robertson, Inc., Water Resources Consultants, November

1982;

o Mathematical Simulations of the Little Creek Watershed, R.D.

Ghioto Water Resources and Civil Engineering, October 1982;

o Engineering Report on Inland Waterways of Florida for Interim

Committee on Inland Waterways of the 1951 Legislature, Gee &

Jenson, Consulting Engineers, Inc., February 4, 1953;

o Hydrologic and Hydraulic Study of the Turkey Lake Watershed,

Ghioto, Singhofen & Associates, Inc., Water Resources and Civil

Engineering Consultants, July 17, 1984;

o The Canal Authority of the State of Florida Annual Report,

Principal Office - Jacksonville, Florida, October 1964;

o Planning Unit Appendix St. Johns River Basin and Intervening

Coastal Areas in Florida, U.S. Department of Agriculture Soil

Conservation Service, Gainesville, Florida, 1969;

o A Study of Water Management Alternatives for the Middle Oklawaha

River Basin, Southwest Florida Water Management District, December

1976 ;

o Report for St. Johns River Basin and Intervening Coastal Areas

Florida, U.S. Department of Agriculture Soil Conservation Service,

Gainesville, Florida, 1969;

o Report to the Governor, Florida Rivers Study Committee, January

31, 1985;

o First Biennial Report of the Florida Department of Water Resources

for the Period October 15, 1957 through December 31, 1958,

Tallahassee, Florida, 1959;

o Second Biennial Report, 1959-1960 Florida Department of Water

Resources January 1, 1959 - December 31, 1960, Tallahassee, Florida, 1961;

o Catalog of Information on Water Data Index to Areal Investigation

and Miscellaneous Water Data Activities, U.S. Department of the

Interior, Geological Survey Office of Water Data Coordination,

o 1980 Annual Report, Lake County Department of Pollution Control

Tavares, Florida, January 1981;

o Hydrologic Records Program for 1979 and 1978 Fiscal Years in

cooperation with Lake County, U.S. Geological Survey, May 25,

1977 ;

o A Report of the Water Quality of A Portion of the South Lake

County Chain of Lakes, Lake County, Florida, Florida State Board

of Health Bureau of Sanitary Engineering, Jacksonville, Florida,

1966 ;

o Preliminary Report on Flood Control Problems Withlacoochee River,

Florida for Department of Water Resources State of Florida,

Maurice H. Come11 & Associates, Inc., Consulting Engineers, March

1961 ;

o Wekiva River Aquatic Preserve Management Plan Draft The Department

of Natural Resources, Bureau of Land and Aquatic Resource

Management, Division of Recreation and Parks, June 1987;

o Re~0rt on Flood of March 15-18.1960 U.S. Armv Enaineer District,

Jacksonville, Office of the District Engineer Corps of Engineers

Jacksonville, Florida, April 1960;

o Comprehensive Drainage Plan Lake County, Florida Phase I1

Hydrologic Evaluation of Basin Segments and Sub-segments, Lake

County Planning Department, October 4, 1978;

o Florida Lakes. Part I A Studv of the Hiah Water Lines of Some

Florida Lakes Part 2 A Tentative Classification of Lake

Shorelines, Division of Water Resources, Florida Board of

Conservation Tallahassee, Florida, 1967;

o Application for Funding Johns Lake Orangebake Counties, Florida

under EPA Clean Lakes Program 40 CFR 35, Subpart H, Johns Lake

Improvement Association Killarney, Florida, February 22, 1990;

, . o Lake County Drainage Atlas, Newman Consulting Engineers, Inc.,

Leesburg, Florida, 1976;

o Hicks Ditch - Horizontal and Vertical Controls Palatlakaha - Horizontal and Vertical Controls River Aerial Map-, St. Johns

River Water Management District, 1990;

o ~lood ~azard Study Black Water Creek and Tributaries Lake County,

Florida, SCS, August 1984;

o Comprehensive Report on Four River Basin, Florida, Part I, Part

11, U.S. Army Corps of Engineers, November 30, 1961; -

o Comprehensive Report on Four River Basin, Florida, U.S. Army Corps

of Engineers, November 30, 1961;

o Four River Basins Project Florida, Plan of Study, U.S. Army Corps

of Engineers, 1975;

o Oklawaha River Basin Flood Damage Study for 1959, High Water,

Florida Department of Water Resources, July 1, 1959;

o Review Report on Oklawaha River Basin, A Survey of Potential

Benefits from Water Control in the Oklawaha River Basin, Water

Resources and Florida Department of Water Resources and Gee &

Jenson, Consulting Engineers, Inc., November 1961;

o Review Report of Oklawaha River Basin, Part I, Chittachattee

Channel, Florida Department of Water Resources and Gee & Jenson,

Consulting Engineers, Inc., January 1961;

o Review Report of Oklawaha River Basin, Part 11, Future Flood

Control Program, Florida Department of Water Resources and Gee &

Jenson, Consulting Engineers, Inc., April 1961;

o Preliminary Investigation and Report on Proposed Impoundment Areas

in Southeast Green Swamp, Polk County, Florida, Florida Department

of Water Resources - Lamar Johnson, February 1961;

o Water Resources of Lake County, Florida Department of Water

Resources, 1960;

o Florida Lakes, Part 111, Gazetteer, Division of Water Resources,

Florida Board of Conservation, 1969;

o Waterways - Comprehensive Regional Plan Series, East Central Florida Regional Planning Council, September 1967;

o Upper Oklawaha River Basin, East Central Florida Regional Planning

Council, February 1973;

o Florida Water and Related Land Resources, St. Johns River Basin,

Florida Department of Natural Resources,. 1970;

o Report on Water Control and Navigation, Lake Apopka Recreation &

Water Conservation & Control Authority, April 1954;

o Design Report, Part IV, Phase I, Palatlakaha River Watershed,

Oklawaha Basin Recreation & Water Conservation & Control

Authority, Gee & Jenson, Consulting Engineers, Inc., August 1967;

o Soil Survey of Lake County Area, Florida, U.S. Department of

Agriculture, Soil Conservation Service, April 1975;

o Final Environmental Statement for Palatlakaha River Watershed,

U.S. Department of Agriculture, Soil Conservation Service, April

1973;

o Hydrologic Records for Lake County, 1970-71, U.S. Geological

Survey, 1972;


Survey, 1973;


Survey, 1974;


Survey, 1975;


Survey, 1977;


Survey, 1978;


Survey, 1979;


Survey, 1980;


Survey, 1981;


Survey, 1982;


Survey, 1983;


Survey, 1984;


Survey, 1985;


Survey, 1986;


Survey, 1987;


Survey, 1988;


Survey, 1989;


Survey, 1990;

o Index to Areal Investigations and Miscellaneous Water Data

Activities, U.S. Geological Survey, 1970;

o Hydrologic Data Index for Florida, U.S. Geological Survey, 1966;

o Index to Catalog of Information on Water Data Surface Water

Stations, U.S. Geological Survey, 1972;

o Catalog of Information on Water Data, U.S. Geological Survey,

1966;

o Index to Catalog of Information of Water Data, Water Quality

Stations, U.S. Geological Survey, 1975;

o Water Resources Data for Florida, Volume 2, pp. 1-770, Volume 2, pp. 771-1451, U.S. Geological Survey, 1975;

o Floodplain Information, Wekiva River - Seminole, Orange, and Lake Counties, Florida, U.S. Army Corps of Engineers Jacksonville,

Florida District, September 1974;

o Floodplain Information, St. Johns River and Lake Beresford,

Volusia, and Lake Counties, Florida, U.S. Army Corps of Engineers

Jacksonville, Florida District, September 1974;

o Florida Rivers Assessment, Department of Natural Resources,

December 1989.

2.6 UNITED STATES GEOLOGICAL SUEWEY (USGS)

The USGS is the water resources agency within the United States Department

of the Interior (DOI). The USGS has provided data ranging from

field-measured values of stormwater stages to special studies on best

management practices for pollutant removal. For this study, CDM contacted

the Orlando, Florida USGS office to obtain data relative to the study area.

The following paragraphs highlight the data obtained:

o Hydrology of Lake County, Florida, Water Resources Investigation

76-72, 1976 - The purpose of this publication was to inventory and appraise the water resources of Lake County and to provide part of

the hydrologic information necessary for coordinated development

of the resources of the County;

o Geohydrologic Reconnaissance of Drainage Wells in ~lorida, Water

Resources Investigations Report 84-4021, 1984 - The general purpose and scope of this investigation was to conduct a statewide

geohydrological appraisal of drainage wells. This report presents

results of investigation from October, 1978 to April, 1982, for

Floridan Aquifer drainage wells, Biscayne Aquifer drainage wells,

and interaquifer connector wells;

o uSGS 1:24,000 and 1:100,000 topographic maps for the study area;

and

o Surface and Drainage Areas of Selected Lakes in Florida, 1965,

USGS Water Resources Division, Florida District.

The following applicable USGS publications are available in CDMfs library:

o ~ibliography of U.S. Geological Survey Reports on the Water

Resources of Florida, 1886-1986, Open-File Report 85-424, 1987,

Fourth Edition - This publication provides a list of USGS reports for Florida.

o Hydrologic Unit Map - 1974 - This report provides a statewide system of numbering major hydrologic units;

o Roughness Characteristics of Natural Channels, 1967 - This publication provides Manning's roughness characteristics from

various USGS studies nationwide;

o Water Resources Data, Florida, Water Year 1989, Volume lA

Northeast Florida Surface Water - This publication provides a summary for all USGS surface water quantity and water quality

gages including location, yearly and monthly statistics, periods

of record, and extreme values for the periods of record. Data for

crest-stage partial-record stations are also included in this

report;

o Water Resources Data, Florida, Water Year 1989, Volume 1B

Northeast Florida Ground Water - This report provides ground water data similar to that discussed for Volume lA;

o Technique for Estimating Magnitude and Frequency of Floods on

Natural - Flow Streams in Florida, 1982, Water Resources Investigations 82-4012 - This publication provides regional regression equations for use in estimating flood flows on natural

streams;

o Ground-Water Hydraulics, 1979, Geological Survey Professional

Paper 708 - This paper provides simplified equations and methods useful in the evaluation of groundwater flows and levels; and

o Flood Hazard Study, Black Water Creek and Tributaries, Lake

County, Florida, 1981 - The objective of this study is to furnish needed technical data to local governments to assist them in

identifying local flood problems and in making decisions related

to land use planning and future development.

In addition to these collected data, the USGS has the following data,

reports, and studies which will be useful as the County completes its SWMP:

o USGS gage data in mean daily, monthly, or water year summary form

are available from the USGS or the Lake County Water Authority

(LCWA) in both digital and hardcopy forms and in the form of

Compact Disk (CD) Read-Only Memory (ROM) from commercial vendors.

o Hydrol:sgic Consideration in Draining Lake Apopka, A Preliminary

Analysis, Open File Report, 1971;

o Hydrologic Considerations in Dewatering and Refilling Lake

Carlton, Water Resources Investigations, Orange, and Lake

Counties, Florida, 1977;

o A Hydrologic Description of Lake Minnehaha, Map Series 54, 1972;

o Hydrology of the Oklawaha Lakes Area of Florida, Map Series 69,

1974 ;

o Potential for Downward Leakage to the Florida Aquifer, Green S w q

Area, Water Resources, Central Florida Investigations. Open File

Report 7.7-71, 1978;

o Lithologic and Borehole Geophysical Data, Open-File Report 78-574,

Green Swamp Area, Florida, 1978;

o Long-Term Water Supply Potential, Green Swamp Area, Florida Water

Resources Investigations 78-99, 1979;

o A Reconnaissance of the Qualitv of Water in Lake Dicie and West

Crooked Lake Near Eustis. Florida. men File Remrt FL-69003.

1969;

o Groundwater in Lake County, Florida Map Series 44, 1971;

o Chemical and Biological Quality of Lake Dicie at Eustis, Florida

with Whasis on the Effects of Storm Runoff. Water Resources

Investigations 36-74, 1974;

o Hydrogeologic maps of a Flood Detention Area, Open File Report

78-460, Proposed by Southwest Florida Water Management District,

Green Swamp Area, Florida, 1978; and

o Distribution and Occurrence of Total Coliform Bacteria in Floridan

Aquifer Wells, Western Lake County, Florida, Water Resources

Investigations Report 84-4130, 1984.

2.7 UNITED STATES ARMY CORPS OF ENGINEERS (USACOE)

The USACOE has traditionally been responsible for civil works involving

water resources and navigation. Within this context, the Jacksonville

District has performed studies and projects involving water resources in

the study area. The following data and reports were obtained from the

USACOE :

o Federal Ehergency Management Agency (FEMA) Flood Insurance Study

(FIS) documents in Lake County (1981), Clermont (1983), Eustis ( 1987 ) , Groveland ( 1982) , Leesburg ( 1985 ) , Mascotte ( 1983 ) , Tavares (1988), Umatilla (1989), Astatula (1982), ~ady Lake

(1983), Mimeola (1982), and Montverde (1982). In most cases,

these documents were delivered in partial form.

o Revised Available Data Report Palatlakaha River Basin, Florida

Volume 6 U.S. Army Corps of Engineers, Jacksonville District,


1981;



Robertson, Inc., Water Resources Consultants, June 1981;

o Available Data Report for the Palatlakaha ~iver Basin, Florida


Robertson, Inc., Water Resources Consultants, December 1980;

o Draft Report for the Palatlakaha River Basin, Florida Volume 2


Robertson, Inc., Water Resources Consultants, January 1981;

Evaluation of Water Resources - Phase I1 Palatlakaha River Basin, Florida U.S. Army Corps of Engineers Jacksonville District,

Seaburn and Robertson, Inc., Water Resources Consultants, November

1982;


Volume I U.S. Army Corps of Engineers Jacksonville District,


1981;

o Floodplain Information, Wekiva River - Seminole, Orange, and Lake Counties, Florida, U.S. Army Corps of Engineers Jacksonville,

Florida District, September 1974;

o Flood~lain Information. St. Johns River and Lake Beresford.

Volusia, and Lake Counties, Florida, U.S. Army Corps of Engineers

Jacksonville, Florida District, September 1974;

2.8 UNITED STATES DEPARTMEW OF AGRICULTURE

SOIL CONSERVATION SERVICE (USDA-SCS)

The SCS is an agency within the United States Department of Agriculture.

Traditionally, their role has been to provide soil surveys and best

management practice guidelines for agriculture. In recent years, the

methods contained in the SCS National Engineering Handbook 4 (NEH-4) (contained in CDM1s library), have been adopted by various state, regional,

and local agencies as part of the regulation of new development.

The SCS was contacted at the Lake County District office. The following

paragraphs briefly discuss the SCS data and reports that were obtained:

o Soil Survey of Lake County, Florida, April 1975 - Standard SCS soil survey for Lake County. The SCS and LCWA are currently

updating the Lake County Soil Survey. The updated soils

information is being entered into the LCWA's Geographic

Information System (GIs) using ARC-INFO. At this time, soil

survey maps for specific areas can be obtained by contacting the

LCWA or SCS office in Tavares. A separate soil survey is

available for the Ocala National Forest. Therefore, it is not

included as part of the soil survey of Lake County and was not

addressed in the recent update. The survey will be used in future

phases of the Stomter Management Program as needed.

o Other data on best management practices, many of which have been

incorporated into the FDER Land Development Manual Chapter 6,

1989.

FEDERAL EMERGENCY MANAGEMENT AGENCY ( F m )

The Federal Emergency Management Agency (FEMA) establishes regulatory

floodplains and floodways by the use of Flood Insurance Studies (FIS). In

addition to the floodplain/floodway data, FEMA FIS reports and/or archives

sometimes provide hydraulic data in digital format. Hence, FEMA was

contacted in order to obtain these data as well as available hydrologic

data for the study area.

2.10 NATIONAL CLIMATIC DATA CENTER (NCDC)

The National Climatic Data Center (NCDC) collects and maintains various

types of climatological data. Precipitation data in digital format were

obtained for the Lisbon and Clermont Stations.

2.11 ST. JOHNS RIVER WATER MANAGEMENT DISTRICT (SJRWMD)

The SJRWMD was officially formed in 1972 by the State Legislature as part

of Chapter 373, F.S. (Florida Water Resources Act). This act provided

initial taxing and permitting authority, which, along with the size of the

SJRWMD boundaries, has increased over the years. Through the 1987 SWIM

Act, the SJRWMD was appointed to be the local state agency in charge of

designing and implementing plans and programs for the improvement and

management of the entire area in the SJRWMD. The following paragraphs

highlight some of the key data obtained from the SJRWMD:

o Technical Publication SJ 79-6 Upper Oklawaha River Basin Water

Management Study, Part 1: Lake Griffin Region Study, 1979 - This report presents evaluations of the Lake Griffin system for large

s t o m under the existing regulation schedule;

o Technical Publication SJ 85-4 Burrell Dam Safety Evaluation, 1985

- This report presents an evaluation of the structural capability of the dam for extreme floods;

o Technical Publication SJ 89-3 Little Wekiva River Floodplain

Study, 1989 - The objectives of the study were to complete a floodplain study and to develop a comprehensive water management

plan for the basin. This report presents the results of the

floodplain study;

o Technical Publication SJ 89-5 Water Quality Assessment of the

Floridan Aquifer in the Wekiva River Basin of Orange, Lake, and

Seminole Counties, 1989 - The purpose of this study is to determine the present condition of water quality in the Floridan

Aquifer in the Wekiva River basin;

o Lake Apopka - Restoration of a Lake - Protection of a River, St. Johns River Water Management District, 1989 - This report describes the plan to improve the quality of Lake Apopka in the

near future. This plan calls for restoration of the lake's

floodplain marsh and increasing the marshes natural water

cleansing capacity;

o Lake Apopka Restoration Progress Report and Recommendations, A Report to the Florida Legislature by the Lake Apopka Restoration

Council (LARC), 1989 - The LARC, in accordance with the Lake

Apopka Restoration Act, is required to provide an annual progress

report to the Legislature. This publication is the fourth report

to the Legislature;

o Technical Publication SJ 90-4 Annual Water Use Survey: 1987, 1990

- Water use data for 1987 were collected by the county for SJRWMD. Graphs and tables present total water use data district-wide and

by category;

o Technical Publication SJ 90-7 Floodplain Study of the Hicks Ditch

Basin in Lake County, Florida, 1990 - This floodplain study is the first step toward the development of a water management plan for

the Hicks Ditch basin;

o Technical Publication SJ 90-10 Upper St. Johns Ground Water Basin

Resource Availability Inventory, 1990 - This report provides a general inventory of the water resources of the Upper St. Johns

(US) groundwater basin, including hydrogeological features,

recharge and discharge areas, groundwater quality,

characteristics, present and projected water use, direct water

reuse, and areas suitable for future water resource development;

o Technical Publication SJ 90-11 Middle St. Johns Ground Water Basin

Resource Availability Inventory, 1990 - This report provides a general inventory of the ground water resources of the Middle St.

Johns (MSJ) groundwater basin, including hydrogeologic features,

recharge and discharge areas, groundwater quality characteristics,

present and projected water use, potential for direct water reuse,

and areas suitable for future water resource development;

o Technical Report SJ 90-12 Annual Water Use Survey: 1988, 1990 - Water use data for 1988 were collected by the county for SJRWMD.

Graphs and tables present total water use for the district and

water use by category;

o Technical Publication SJ 88-6 Development of Site-Specific

~ypothetical Storm Distributions, 1988 - This report provides an initial approach to developing site-specific storm distributions;

o Technical Publication SJ 88-3 Rainfall Analysis for Northeast

Florida Part VI: 24-Hour to 96-Hour Maximum Rainfall for Return

Periods 10 Years, 25 Years, and 100 Years, 1988 - his report provides new design rainfall amounts for the various storms;

o Pan evaporation data for Lisbon and Lake Alfred, Florida;

o District policy Number 79-17 which describes SJRWMD procedures for

data acquisition;

o Lake County lakes printout;

o Lake County rainfall printout;

o Lake County wells printout; and

o Photomap index of SCS Blackwater Creek Flood Hazard Study.

The following SJIiWMD reports are available in CDMfs library:

o SJRWMD Management and Storage of Surface Waters (MSSW) Applicant's

Handbook, 1989;

o Draft SWIM Plan for the Upper Oklawaha River Basin, 1989;


Florida Part 11: Summary of Monthly and Annual Rainfall Data,

1986 - This report provides the summaries as indicated;


Florida Part I: 24-Hour to 10-Day Maxirmm Rainfall Data, 1986 - This is the base or initial report for the rainfall updates in the

o Technical Publication SJ 86-2 Magnitude and Frequency of Flood

Discharges in Northeast Florida, 1986 - This report provides regional regression equation approaches for northeast Florida;

Technical Publication No. SJ 85-8 Application of Landsat Data in

District Water Resources ~nvestigations and Management, 1985 - This report provides information on the SJRWMD plan to use LANDSAT

for land use mapping, including experimental programs in deriving

runoff parameters such as curve numbers and a wetlands inventory

for Duval County;

o Technical Publication No. SJ 85-5 A Guide to SCS Runoff

procedures, 1985 - This report provides standard USDA-SCS procedures and guidelines in a condensed form;

o Interim Water Quality Management Plan, 1985 - This report presents an interim approach to water quality management for the District

surface waters, including some specific discussion of the Lower

St. Johns River;

o Water Quality Monitoring Field Manual, 1983 - Water quality field guidelines for equipment, measurements and collection, handling,

and quality assurance are presented;

o Technical Publication SJ 83-2 St. Johns River Water Management

District Current Population and Projections - 1980, 1983 - /9

Population projections are presented by surface water basin,

region, and county;

o Technical Publication SJ 83-6 Hydrologic and Engineering Study for

Extreme Drawdm of Little Griffin - Part 1, 1983 - This publication investigates the economic and technical feasibility

and impacts of drawing down the lake to improve the sportfish

habitat;

o Technical Publication SJ 82-1 Frequencies of High and Low Stages

for Principal Lakes in the St. Johns River Water Management

District, 1982 - For different principal lakes in the District, this publication provides information on the past levels (i.e.,

monthly mean elevations, and high and low elevations recorded for

different continuous periods) and the future expected elevations

evaluated by frequency analyses; and

o Technical Publication SJ 81-1 Structural Geolouic Features and

Their relations hi^ to Salt Water Intrusion in West Volusia. North

Seminole, and Northeast Lake Counties, 1981 - Salt water intrusion of wells in the St. Johns River Valley between Lakes George and

Monroe (northeast Lake, North Seminole and west Volusia Counties)

prompted this report to evaluate impacts on local farmers and

other interests.

The District also has an ongoing study of the Oklawaha River Basin which is

re-evaluating lake regulation schedules. This, and an accompanying

socio-economic study, are not yet completed.

2.12 SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT (SWFWMD)

The SWFWMD was officially formed in 1972 by the State Legislature as part

of Chapter 373, F.S. (Florida Water Resources Act). This act provided

initial taxing and permitting authority, which has increased over the

years. Through the 1987 SWIM Act, the SWFWMD was appointed to be the local state agency in charge of designing and implementing plans and programs for

the improvement and management of the entire area in the SWFWMD. The

following SWFWMD data, reports, and studies have been obtained:

o Aerial mapping index for portions of the Green Swamp basin in

southwest Lake County;

Florida, 1987; and

o Groundwater Resource Availability Inventory for Polk County,

Florida. 1987.

2.13 FLORIDA DEPARTMEIVT OF ENVIRONMENTAL REGULATION (FDER)

o Groundwater levels from both deep and shallow monitoring wells in

digital format; and

o SWFWMD Management and Storage of Surface Waters (MSSW) Permit

Information Manual.

The following studies have been ordered from the District:

o Groundwater Resource Availability Inventory for Sumter County,

The State Legislature enacted Chapter 373, F.S. in 1972 (Florida Water

Resources Act of 1972). The Act established and empowered the FDER to

study and propose a state water use plan. Eventually, the Department

received additional regulatory authority. Currently, the FDER regulates or

makes comments on nearly any significant environmental permitting activity.

The following FDER data and reports have been obtained:

o Copy of Interactivation and Precipitation of Urban Runoff Entering

Lake Ella by Alum Injection in Stomewers;

o Florida Nonpoint Source Assessment, Volume One, Draft, 1988 - Section 319 of the 1987 Federal Clean Water Act requires all

states to assess the impact of nonpoint sources of pollution on

their water bodies and to develop a plan and program to abate

them. To meet these requirements, the Nonpoint Source Management Section of the FDER has prepared a two volume report. Volume One contains the statewide assessment of nonpoint source impacts on

surface and ground waters;

o Directory of Injection Well Facilities, Department of

Environmental Regulation Groundwater Management System, August 16,

1990 - Database providing information on injection well facilities within Lake County, including those used for drainage and lake

level control;

o Recommended objections used by FDER and DCA for reviewing

stormwater management subelements of comprehensive plans;

o Water Oualitv and Se~tic Tanks Site Assessments: St. Lucie

Countv. St. Johns Countv. Lake Countv. Dixie Countv. Hernando

County, and Monroe County, Florida Department of Environmental

Regulation; and

The following FDER data and reports are in CDMts library:

o The Florida Land Development Manual, 1989 - This manual provides a wide range of sound development practice guidelines; and

o Copy of Operational Results from the Restoration of Lake Ella. A

project in which alum injection systems were used to provide

chemical stormwater treatment in an urbanized area.

o Copies of Environmental Exchange Point Newsletters, Office of

Planning and Research - This publication is produced to help prepare local government comprehensive plans.

2.14 FLORIDA DEPAR- OF TRANSPORTATION (FDOT)

The Drainage Section or Drainage Design Office is a subsection of the

Florida Department of Transportation (FDOT) responsible for roadway

drainage, stomter management, and bridge hydraulics for state-maintained

roadways. The following information was obtained from the FDOT Deland

off ice:

o Bridge map showing locations and identification numbers;

o General highway map showing State Highway system with

identification numbers;

o Bridge construction detail plans for selected Lake County bridges;

anca

o Inventory list for state road straight-line diagrams in Lake

County.

In addition, the following data have been obtained from the Florida

Turnpike Authority:

o Straight-line diagram showing roads and stormwater management

facilities for the Florida Turnpike in Lake County.

Further coordination with the FDOT for specific facility data details will

be done during future phases of the County's Stormwater Management Program.

2.15 FLORIDA DEPARTMJ3NT OF COMMUNITY AFFAIRS (DCA)

FLORIDA DEPARTMENT OF COMMUNITY AFFAIRS

The DCA is the implementation agency for State Comprehensive Plan (Chapter

187, Florida Statutes). Chapter 9J-5, FAC outlines local comprehensive

plan elements which are submitted to the DCA after receiving comments from

the local regional planning council (such as the East Central Florida

Regional Planning Council).

The DCA has produced several documents to assist local governments in

meeting the requirements of the 1985 and 1986 Growth Management

legislation. By steering local planners to the key resources that will

help them understand the issues confronting their communities, the

documents can better prepare local officials and the public to make the

kinds of critical decisions that Florida's future growth demands. The

following DCA publications were obtained:

o Preparing a Comprehensive Plan, Practical Considerations in

Meeting Florida's Local Planning Requirements, May 1987 - This document's intent is to enable local governments to engage in the

type of planning process which meets the staters planning

requirements, and which effectively responds to the community's

needs and priorities for directing future growth.

o Sanitary Sewer, Solid Waste, Drainage, Potable Water, and Natural

Groundwater Aquifer Recharge Element - Model Element, May 1987 - This "model element" is one of eleven prepared by the DCA in

response to Chapter 163, Florida Statutes. The purpose of this

model or sample element, is to provide an example of one approach

that would be found in compliance with that Chapter.

o A Guide to Local Government Comprehensive Planning Data Sources, A

Directory to Assist Local Governments in Preparing Local

Comprehensive Plans Pursuant to Chapter 163, F.S. and Chapter

9J-5, FAC, November 1986 - The DCA has prepared this publication to assist local governments in identifying sources of information

that are considered useful for comprehensive planning purposes.

EAsT CENTRAL FLORIDA REGIONAL PLANNING COUNCIL (ECFRPC)

One of the primary activities of the ECFRPC, located in Orlando, is to

review Developments of Regional Impact (DRI) and provides planning

assistance to local communities. Since the ECFRPC is the lead agency in

the review process for DRIs, CDM contacted this entity in order to obtain

stornrwater facility information contained in all DRIs and other applicable

planning data.

The following ECFRPC publications have been obtained:

o 208 Areawide Water Quality Management Plan, Orlando (FL)

Metropolitan Planning Area, 1978;

o Floodplain Maps in the Lake County Conservation Element;

o Lake County Land Use Mapping Project, Comprehensive Planning

Assistance Program, November, 1986 - This report summarizes and presents the land use mapping and planning assistance performed by

the ECFRPC for the Lake County Board of County Commissioners. It

will provide Lake County with the maps needed to fulfill the

existing land use requirements of Chapter 9J-5, FAC;

o Upper Palatlakaha Basin Comprehensive Water Study, Technical

Report, May 1983, East Central Florida Regional Planning Council;

o Upper Palatlakaha Comprehensive Water Study Water Quality Report,

September 15, 1982, Lake County Department of Pollution Control;

o Review of Approaches and Techniques Used in the Financing of

Retrofit Stornrwater Management Projects, 1985-1986 - This publication is intended to present a summary review of financial

alternatives that have been used to fund the undertaking of

retrofitted improvements to existing storm drain systems in urban

areas and techniques which offer potential for possible use in

alleviating the funding problem; and

o Results and Findinas of an Urban Stormwater Runoff

Retentionfletention Facility Pollutant Removal Monitoring Project,

August 1983 - The objective of the project was to determine the pollutant removal efficiency of a small-sized stormwater

retention/detention facility located in a built-up, developed

urban area.

3.0 HYDROLOGIC/HYDRAULIC BACKGROUND

MAJOR BASINS

Lake County is approximately 1,172 square miles in size and includes a

portion of the Ocala National Forest. Average rainfall is approximately 51

inches and much of the County provides recharge to the Floridan Aquifer,

Florida's primary supply of potable water. The County lies on the central

Florida hydrologic divide which causes discharge of surface and intercepted

groundwater to both the Atlantic Ocean and the Gulf of Mexico. Elevations range from near sea level along the St. Johns River to over 300 feet at

Sugar Loaf Mountain.

The County is aptly named due to the presence of more than 1,300 lakes.

Most of these lakes were created by erosion of underlying carbonaceous

bedrock causing a Karst topography and sinkholes connecting surface waters

to the aquifers. Two stream-to-sinkhole systems have been identified:

Wolf Branch sink east of Mount Dora, and the Shocklee Heights area sink in

the Ocala National Forest northeast of Lake Dora. Portions of the County contain considerable physical relief (e.g., Mount Dora Area) with well

drained soils while other portions are flat and comprised of extensive

wetlands (e.g., Little Everglades). Surface streams and rivers, such as

the Oklawaha and Withlacoochee Rivers, convey surface and groundwater

discharges out of the County on their way to the Atlantic Ocean and Gulf of

Mexico, respectively. The Lake County Conservation and Groundwater

Recharge Elements of the Countyts Comprehensive Plan provide further

details on conservation and groundwater aspects of the hydrology of Lake

County.

Lake County contains five major hydrologic basins: Oklawaha River,

Withlacoochee River, Wekiva River, Kissimmee River, and the St. Johns

River. These major hydrologic basins are shown on Figure 3-1 and are

described below. These descriptions provide basic facts about location,

size, and stream systems. The identification of problem areas, data

evaluations, and recommendations for each major basin are addressed in

other sections within this report.

0Fz=Y-F7

m 11 es

WITHLACOOCHEE

OKLAWAHA

LEGEND

- MAJOR BASIN DIVIDE

WITHLACOOCHE RIVER

MAJOR BASINS enwronmen to1 engrneers, scren tists.

planners, a monogemen t consultants CDM FIGURE 3-1

3.1.1 OK- RIVER

Approximately 50 percent of the County lies within the Oklawaha River Basin

which extends from Polk County to the south and Marion County to the north.

The contributing area within Lake County for the Oklawaha River Basin is

approximately 582 square miles and the direction of flow is generally south

to north. The Oklawaha River discharges to the St. Johns River, north of

Palatka. It also receives flows from portions of Orange and Lake Counties.

The upper Oklawaha River Basin, as found in Lake County, consists of the

majority of major lakes, streams, and rivers in the County. The two main

lake chains, the Palatlakaha Chain and the Apopka Chain are divided by the

Lake Wales Ridge. A series of streams and canals connect the Palatlakaha

Chain which extends from Lake Louisa in southern Lake County to Lake Harris

where it connects to Lake Eustis via the Dead River. The most distant

water source of the lakes in this chain is the eastern portion of Green

swafig*

The second principal lake chain, the Apopka Chain, extends from Lake Apopka

in Orange and Lake Counties through Lake Griffin. The major lakes of this chain are connected by canals or channelized waterways. In both lake

chains, the flow is regulated by lock and dam structures. Several freshwater springs are located within the Upper Oklawaha River Basin.

RIVER

Approximately 17 percent of the County lies within the Withlacoochee River

Basin which extends from the northeastern part of the County adjacent to

the Town of Lady Lake to the southwestern part in the Green Swamp area,

which is a large wetland area that serves as the headwaters for several

river systems. The Withlacoochee River Basin area within Lake County is

approximately 201 square miles and the direction of flow is generally north

to south. The Withlacoochee River ultimately discharges into the Gulf of

Mexico.

3.1.3 WEKIVA RIVER

Approximately 18 percent of the County lies within the Wekiva River Basin.

Located in the northeastern part of the County, the basin extends from Lake

Dorr southeasterly along Blackwater Creek to its confluence with the Wekiva

River, near the Lake/Orange County border. At this point, the Wekiva River

flows northeast outfalling into the St. Johns River which discharges into

the Atlantic Ocean at Jacksonville, Florida. The Wekiva River Basin area

within Lake County is approximately 205 square miles.

3.1.4 KISSIMMEE RIVER

Approximately 2 percent of the County lies within the Kissimmee River

Basin. Located in the southeastern part of the County, the basin extends

from Trout Lake to the LakePolk County border. The Kissimmee River Basin

area within Lake County is approximately 21 square miles and generally

flows north to south. The Kissimmee River flows south and ultimately

discharges to Lake Okeechobee.

3.1.5 ST. JOHNS RIVER

Approximately 14 percent of the County flows directly into the St. Johns

River. Located in the northeastern part of the County, the basin extends

from Alexander Springs in the Ocala National Forest to the Town of Astoe:

adjacent to the river. The St. Johns River Basin area within Lake County

is approximately 166 square miles and generally flows south to north.

3.2 HYDROLOGIC BOUNDARIES

Hydrologic boundaries are needed to identify flow directions and schemes as

well as contributing area acreages. As agreed upon with Lake County,

hydrologic boundaries for major basins (e.g., Oklawaha River), sub-basins,

and smaller hydrologic units were derived from SJRWMD and SWFWMD estimates

coupled with the Lake County Drainage Atlas. These boundaries were

digitized as AutoCAD layers at the USGS 7.5 minute quadrangle scale

(1"=2000t). Appendix B contains the Hydrologic Boundary Map for Lake

County and lists the five major basins with their respective hydrologic

sub-basin areas. The five major basins are comprised of 18 sub-basins and

250 hydrologic units.

3.3 TOPOGRAPHY

Topographic data are needed to define hydrologic boundaries, overland flow

slopes, channel slopes, and stage-area-storage relationships. Topographic data are available for the entire County from the USGS as 1:24,000 (7.5

minute series quadrangles with 5-feet contours) and 1:100,000 scale maps

(5-feet contours). One-foot contour topographic-aerials (scale 1"=200t)

also exist for portions of the County as available from the LCWA and

SWFWMD. Figure 3-2 shows the extent of this detailed topographic coverage.

3.4 AERIAL PHOTOGRAPHY

Aerial photographs aid stormwater evaluations in land use verification,

basin delineations, hydraulic facility identification, calculation of

overland flow lengths, floodplain storage encroachment, and survey

requests.

Aerial photographs are available from the LCWA and SWFWMD with topography

for much of the County (at a scale of 1"=200t). In addition, the standard

FDOT aerials are available through Lake County, and Real Estate Data Index

(REDI) maps are also available at various scales.

The LCWA and SWFWMD topographic-aerials, augmented by either FDOT or REDI

aerials where needed, are recommended for use in future phases of the

County's Stormwater Management Program.

3.5 SOILS

Soils data are used to evaluate stormwater runoff, infiltration, and

recharge potential. Specifically, infiltration rates and total soil

storage (related to curve number) are used in hydrologic models.

0 1 2 4 6 8

miles

. . . . . . . . . .

LEGEND

AREA OF TOPOGRAPHIC- AERIAL COVERAGE BY LCWA

AREA OF TOPOGRAPHIC- AERIAL COVERAGE BY SWFWMD

DETAILED TOPOGRAPHIC COVERAGE en vironmen fa1 engineers, scien fists,

planners, & management consu/tants CDM FIGURE 3-2

Information on soil types and engineering characteristics can be obtained

from soil survey reports produced by the Soil Conservation Service (SCS).

The Lake County and Ocala National Forest Soil Surveys are in the process

of revision and should be available for future stomter projects. This

information may also be available in digital form through the LCWA ARC-INFO

system. Site specific soils studies can also be used to augment or clarify

SCS reports as they are submitted for specific developments.

The Generalized Soil Map in the Lake County Soil Survey (1975) was used to

identify soil types for the eighteen sub-basins. Figure 3-3 shows this

preliminary mapping of generalized soil types in Lake County, and Appendix

B contains a table which lists soil types by sub-basin.

In general, hydrologic group A and B soils can be used for infiltration

Best Management Practices (BMPs) as well as detention BMPs, while

hydrologic group C and D soils are suitable for wet detention BMPs only,

although in some cases, swales can be used in type C soil areas. Wetland

creation/enhancement is best achieved in type D soils, but also in other

type soils if an impermeable pond bottom material such as clay is used.

Section 5.0 provides background discussion of soil types.

3.6 RAINFALL

Rainfall data are used to generate the basis for stormwater evaluations.

Data are generally characterized by amount (inches), intensity (inches per

hour), frequency (years), duration (hours), temporal (time) distribution,

and spatial distribution. Rainfall amounts for the Lake County area are

shown on Figures 3-4 through 3-8 for the 1-, lo-, 25-, and 100-year 24-hour

storm events and the 25-year, 96-hour storm event.

Based upon these storm event rainfall amounts and the location of the major

basins in Lake County, rainfall amounts and peak rainfall intensities were

developed for the major basins, along with a recommended temporal

distribution. This information is presented in Table 3-1.

FIGURE 3-3

0-

miles

HYDROLOGIC SOIL GROUP

POLK

GENERALIZED SCS SOILS environmen to/ engineers, scien fists.

planners. & monogemen t consulton ts CDM*

p.,+& ST. JOHNS RIVER WATER MANAGEMENT DISTRICT

4L-22 NASSAU

--

!

4.4

MEAN ANNUAL 24-HOUR MAXIMUM RAINFALL FOR NORTHEAST FLORIDA, INCHES

environmen to1 engineers, scfen tists, planners, & management consultants CDM

FIGURE 3-4

ST. JOHNS RIVER WATER MANAGEMENT DISTRICT

I

10-YEAR 24-HOUR MAXIMUM RAINFALL FOR NORTHEAST FLORIDA, INCHES ADAPTED FROM SJRWMD, 1988

FIGURE 3-5


FOR NORTHEAST FLORIDA, INCHES

FIGURE 3-6


N

100-YEAR 24-HOUR MAXIMUM RAINFALL FOR NORTHEAST FLORIDA, INCHES ADAPTED FROM SJRWMD, 1 9 8 8

FIGURE 3- 7


ADAPTED FROM SJRWMD, 1988

FIGURE 3-8

TABLE 3-1

DESIGN STORMS RECOMMENDATIONS FOR THE MAJOR BASINS

STORM STORM EVENT EVENT RAINFALL

RAINFALL FREQUENCY DURATION AMOUNT MAJOR BASIN DISTRIBUTION (YR) (HR (IN)

Oklawaha River SCS Type I11 1 2 4 4.2 and 2 2 4 4.8

Kissimmee River 5 2 4 5.9 10 2 4 6.7 2 5 2 4 8.5 5 0 24 9.8 100 24 11.5

Wekiva River SCS Type I11 1 2 4 4.3 and 2 2 4 4.9

St. Johns River 5 2 4 5.9 10 2 4 6.5 25 2 4 8.3 5 0 2 4 9.6 100 2 4 11.3

Withlacoochee SCS Type 111 1 2 4 4.2 River 2 2 4 4.8

5 2 4 6.0 10 2 4 6.8 2 5 2 4 8.5 5 0 2 4 10.0 100 24 11.8

PEAK RAINFALL INTENSITY

( IN/HR)

NOTES :

(1) The SCS Type I11 rainfall distribution was formerly called the SCS Type II-Modified or Florida-Interim.

(2) Rainfall amounts for the 1-, lo-, 25- and 100-year, 24-hour storms are taken from SJIWMD Technical Publication 88-3 "Rainfall Analysis for Northeast Florida". Rainfall amounts for the 2-, 5-, and 50-year, 24-hour storms are derived from a least squares regression of rainfall amounts for the other storms.

(3) The rainfall amount for the 25-year, 96-hour storm for landlocked areas is recommended to be 11.0 inches for all basins using an SCS Type 111 distribution.

Orlando, Lake Alfred, Deland, Sanford, Isleworth, and Eustis. The active

recording locations are shown in Figure 3-9. Table 3-2 presents the mean

and maximum annual precipitation amounts for the recording locations.

These data were used to screen for historic Levels Of Service and for

potential calibration storms.

A time series evaluation was performed using the rainfall data mentioned

above. Of the significant rainfall events isolated (greater than 2.0

inches), those with the least spatial variance were designated as possible

calibration events. The ideal calibration storm would be relatively recent

(within five to ten years) and be of a frontal nature with rainfall evenly

distributed over an entire basin or the entire study area. In addition,

the ideal storm should be on the order of magnitude of one of the larger

storm events (e.g., lo-, 25-, and/or 100-year frequency) to help calibrate

and verify design storm simulation results. Such an ideal storm was not

found for this study due to the lack of significant rainfall events in

recent years. However, the January 10-11, 1986 rainfall event represents a

widely-distributed, significant event which produced rainfall amounts of

5.4 inches at Lisbon and 4.9 inches at Clermont. This corresponds to approximately a 2- to 3-year frequency storm and is recent enough for

present hydrologic and hydraulic conditions to be applicable. Another

possible calibration event is the November 23, 1988 rainfall event which

was concentrated over the southern portion of the County producing 6.9

inches at Clermont and 1.9 inches at Lisbon. Table 3-3 shows the results

of a historic storm analysis for Lake County.

Based upon this evaluation, it appears that adequate calibration data exist

for future stormwater calibration modelling efforts.

3.7 STAGE AND DISCHARGE

An essential component of any water resources investigation is the

availability of measured stages and/or discharges at selected points of

interest. These are often used to establish base flows or normal

conditions as well as predict extreme flood and/or drought event

conditions.

LEGEND

RAIN GAGE STATION - DISTRICT BOUNDARY

--.- STATE BOUNDARY

-.- COUNTY BOUNDARY

TABLE 3-2

RAINFALL SUMMARY FOR WCE COUNTY AREA, FLORIDA

Mean Maximum Period of Record Rain Gage Annual Annual

Precipitation Precipitation ( inches ) ( inches )

Bushnell 50.50 77.11 1950-1989

Clermont 51.30 68.09 1949-1989

Inverness 55.59 86.97 1950-1989

Lake Alfred 51.28 75.81 1959-1989

Ocala 53.95 74.71 1949-1989

Orlando 48.32 56.79 1975-1989

Sanford

AVERAGE

TABLE 3-3

ESTIMATED WATER QUANTITY BASED ON HISTORIC STORMS

AF'PROXIMATE 3-GAGE STORM

AF'PLICABLE GAGES AND AVERAGE FREQUENCY MAJOR BASIN RAINFALL AMOUNTS ( INCHES) ( IN) (YR)

LISBON CLERMONT WCE ALFRED OK- RIVER 5.4 6.9 4.8 5.7 5

WEKIVA RIVER & LISBON DELAND SANFORD ST. JOHNS RIVER 5.4 5.0 6.7 5.7 5

WITHLACOOCHEE L I SBON CLERMONT BUSHNELL RIVER 5.4 6.9 6.0 6.1 5

KISSIMMEE ISLEWORTH CLERMONT WCE ALFRED RIVER 5.0 6.9 4.8 5.6 5

NOTES :

(1) All rainfall values were rounded to the nearest 0.1 inch.

(2) The three most applicable gages were used to triangulate for a given basin.

(3) Level of Service frequencies were estimated as the storm which most evenly matched the 2-, 5-, lo-, 25-, 50-, or 100-year events.

Typically, for a stormwater master plan, stages and/or discharges are used

in conjunction with known rainfall amounts/distributions and other

hydrologic/hydraulic conditions to calibrate and verify models. These calibrated and verified models can then be used in evaluations of present

problem area solutions or future conditions planning. It is often

desirable to acquire these data in at least hourly intervals such that

relatively short term, yet potentially damaging, flood peaks can be

predicted and planned for.

For this study, CDM contacted various sources for such data including the

following:

o The USGS for stage values at the twenty gages recording lake

stages in the study area (Table 3-4 and Figure 3-10);

o The USGS for discharge values at the twenty-one gages recording

stage and flow for streams in the study area a able 3-5 and Figure 3-11 ) ;

o The USGS for partial-record crest-stages and other miscellaneous

sites in the study area;

o The USGS for major well data in the County (Table 3-6); and

o The SJRWMD and the LCWA for any available stage/discharge data.

In general, there appears to be adequate stage and/or discharge data for

the stormwater master plan and detailed basin plan efforts, however, the

necessary unit (or hourly) stage values will require a special retrieval

from the USGS computer database at that time.

3.8 FLOODPLAINS AND FLOOJ3WAYS

A floodplain is basically the area inundated by a particular flood event.

Floodplains are often described by their frequency of occurrence (e.g.,

25-year, 100-year).

TABLE 3-4

USGS LAKE GAGES IN THE STUDY AREA

PERIOD NATERBODY GAGE # OF RECORD LOCATION

Lake Lowery Southeast end of Stub Canal on south side of lake

Lake Nellie

Lake Louisa

Lake Minnehaha

1.8 mile east of SR 561

North shore or lake

Southeast side of SR 561 bridge

Lake Asphawa Northwest shore of south portion of lake

Cherry Lake Southwest shore of lake, 21' upstream from outlet

Church Lake West shore of lake, 0.8 mile south of U.S. 27

Lake Harris

Johns Lake

Northwest shore of lake

North shore of lake, 0.4 mile south of SR 50

Lake Apopka Southeast corner of west boat basin

Lake Francis North shore of lake at Errol Estates (Orange County)

West Crooked lake East shore of southeast bay of lake

Lake Dora

Lake Umatilla

Lake Eustis

Silver Lake

West shore of lake

South shore of lake

Northeast shore of lake

West shore of lake

TABLE 3-4 (continued)

USGS LAKE GAGES IN THE STUDY AREA

PERIOD WATERBODY GAGE # OF RECORD LOCATION

Lake Yale 02238200 9/59 - C East bank, southeast side of lake

Lake Griffin 02238300 5/36 - C West portion of lake

Lake Dorr 02235150 8/65 - C West shore of lake

Lake Catherine 02312670 9/65 - C Northeast shore of lake

Lake Odom 02236119 11/80-C Southwest shore of lake

,---4--

L -------- _I 1 I

POLK COUNTY

USGS LAKE GAGES environmen to1 engineers, scientists,

planners. & monogemen t consu/tont~ CDM FIGURE 3-10

TABLE 3-5

USGS STREAM GAGES IN THE STUDY AREA

PERIOD OF RECORD m-DY

Tracy Canal

GAGE #

02235192

LOCATION

On left bank at downstream side of culverts on county road, 0.5 mile upstream of Lake Norris 2.1 mile downstream from Lake Tracy

St. Johns River Near Deland, FL

Left bank on downstream side of Francis P. Whitehair Bridge, SR 44, 142 mile upstream from mouth

Blackwater Creek

Big Creek

At bridge SR 44, 13 mile upstream from mouth

Near left bank 40 feet downstream from Log Bridge, 1 mile upstream from mouth to Lake Louisa

Little Creek 0.6 mile upstream of Lake Louisa

Palatlakaha River at Cherry Lake

21 feet upstream of outlet of Cherry Lake

Palatlakaha River at Cherry Lake

20 feet downstream of outlet of Cherry Lake

Palatlakaha River near Mascotte, FL

260 feet upstream of spillway, 0.4 mile downstream of bridge at SR 565

Palatlakaha River near Mascotte, FL

250 feet downstream of spillway, 0.4 mile downstream of bridge at SR 565

Palatlakaha River at Structure M-6

50 feet upstream of Control Structure M-6

TABLE 3-5 (continued)

USGS STREAM GAGES IN THE STUDY AREA

PERIOD OF RECORD GAGE #

02237011

LOCATION

Palatlakaha River Below Structure M-6

150 feet downstream of Control Structure M-6


50 feet upstream of Control Structure M-6

Palatlakaha River Below Structure M-5

150 feet downstream of Control Structure M-5


50 feet upstream from Control Structure M-4


150 feet downstream from Control Structure M-4


150 feet upstream from Control Structure M-1

Apopka - Beauclair Canal

80 feet upstream from lock and dam

Apopka - Beauclair Canal

300 feet upstream of bridge at CR 48

Haines Creek 900 feet upstream of bridge at SR 44

Haines Creek 750 feet upstream of bridge at SR 44

Lake Nellie Outlet Private pier on southwest shore of lake.

0-

rn~les

LEGEND

02240000 ki STREAM GAGE AND ID NUMBER

USGS STREAM GAGES enwronmen to1 engineers, soen t~sts.

planners. & monogemen t consulton ts CDM. FIGURE 3-77

TABLE 3-6

USGS WELL GAGES IN THE STUDY AREA

WELL I.D. # PERIOD OF RECORD LOCATION

East side SR 33, 1,000 feet north of SR 474

East side SR 33, 1,000 feet north of SR 474

South of SR 565, 800 feet west of Seaboard Coastline Railroad Crossing

East side of SR 565, 3.6 mile south of SR 50

East side of SR 565, 3.6 mile south of SR 50

Lake Avenue, 0.2 mile north of SR 50

North side of Little Lake Harris, 0.2 mile west of SR 19

On west side of College Street, near water tank, 350 feet north of Main Street

North side of Herlong Park, 450 feet north of US 441

70 feet east of SR 454, 2.7 mile south of Astor Park

200 feet north of SR 40, 1 mile west of St. Johns River at Astor Park

Two classifications of floodplains are typically considered in stormwater

analyses: tidal and stormwater. Tidal floodplains are the result of tide

and wind generated flood stages while stormwater (sometimes called fluvial)

floodplains are associated with riverine flooding resulting from rainfall.

It is common practice for FEMA floodplain studies to consider tidal and

stormwater flood events to be independent of one another and then

superimpose the independent results upon each other to produce

comprehensive tidal/stormwater floodplain maps. For Lake County, only

riverine floodplains occur. Therefore, evaluations in Lake County do not

need to consider tidal effects.

A floodway is often defined specifically by the FEMA standard. For

example, Section 2.0(k) of the SJRWMD MSSW Applicant's Handbook states in

part:

"Floodway - The permanent channel of a stream or other watercourse, plus any adjacent floodplain areas that must be kept

free of any encroachment in order to discharge the 100 year flood

without cumulatively increasing the water surface elevation more

than a designated amount (not to exceed one foot except as

otherwise established by the District or established by a Flood

Insurance Rate Study conducted by the Federal mergency

Management Agency (FEMA))."

Proper floodplain/floodway data are critical to guiding new development in

the establishment of first-floor elevations, road crown elevations, lake

control structure and tailwater elevations, allowable fill quantities/

encroachments, and facility sizing.

Floodplains and floodways have been predicted by FEMA in Flood Insurance

Studies (FISrs) for the County and Incorporated Areas; however, CDM has

only been able to obtain portions of these data. Therefore, these data are still being sought to prepare for master plan needs. For this M, CDM

will coordinate with ongoing FEMA efforts to ensure that the planning

efforts of this program will be consistent with accepted flood insurance

standards and methodologies.

3.9 LAND USE AND GROWTH TRENDS

Land use data are used to estimate imperviousness, runoff, and pollutant

load potential in stormwater evaluations. Relative changes in land use are

also used to identify areas of high growth for the estabishment of

priorities for study.

Present land use (1986), as supplied by the Lake County Planning

Department, was used to estimate land use by percentages for each of the

eighteen subbasins. Table 3-7 lists the ten land use groupings used by

CDM to characterize areas based on similar runoff and pollutant load

potential. Table 3-8 shows the correlation between the CDM categories and

Lake County categories. Appendix B provides a list of land use percentages

by subbasin.

The future land use element was not completed in time to be included in

this study; however, relative changes in population have been assessed and

were used by CDM to characterize high growth areas to help establish

priorities for the Stormwater Master Plan. The following Growth Areas were

defined jointly by CDM and the Lake County Planning Department in order to

estimate relative changes in imperviousness:

o High Growth - greater than 67 percent population change;

o Medium Growth - between 33 and 67 percent population change; and

o Low Growth - less than 33 percent population change.

Most of the County is expected to experience medium growth while high

growth areas tend to be in the Oklawaha River Basin and Lady Lake areas.

Figure 3-12 shows the respective zones.

TABLE 3-7

IMPERVIOUSNESS BY LAND USE CATEGORY

LAND USE CATEGORY

1. Forest, Open, and Park

2. Agricultural and Golf Courses

3. Pasture

4. Low Density Residential

5. Medium Density Residential

6. High Density Residential

7. Light Industrial, Commercial, and Institutional

8. Heavy Industrial

9. Wetlands

10. Watercourses and Waterbodies

PERCENT 1MPERVIous~ ' 2 , DCIA

' ' Total Impervious Area.

( ' Directly Connected Impervious Area (DCIA) .

TABLE 3-8

CDM vs COUNTY LAND USE CATEGORIES

CDM ECFRPC

1. Forest, Open, & Park

2. Agricultural and Golf Course

3. Pasture

4. Low Density Residential

5. Medium Density Residential

6. High Density Residential

7. Light Industrial, Commercial, & Institutional

8. Heavy Industrial

9. Wetlands

10. Watercourses & Waterbodies

Recreational Vacantflndeveloped Forested Uplands Other Barren Lands Altered Lands

Agricultural

Range land

Residential (S.F. - Low Density)

Residential (S.F. - Medium Density) Residential (M.H. - Medium -

Density ) Mixed Residential Residential Under Construction Mixed Use

Residential (S.F. - High Density) Residential (M.H. High Density ) Residential (M.F. - Low Rise) Residential (M.F. - High Rise) Commercial and Services Industrial Transportation Communication and Utilities Public/Institutional Extractive

Industrial

Wetlands

Water

0-

miles

MARION

LEGEND

1-1 HIGH GROWTH

1-1 MEDIUM GROWTH

LOW GROWTH

NOTE: GROWTH DESIGNATIONS ARE AS DEFINED BY LAKE COUNTY PLANNING DEPARTMENT

HIGH GROWTH AREAS environmental engineers, scientists.

planners, & manogemen t consultants CDM FIGURE 3-12

REGIONAL AQUIFER CHARACTERISTICS

The Lake County Chapter 9J-5, FAC Groundwater Recharge and Conservation

Elements present various data on regional aquifer characteristics; however,

it is important to correlate the following issues to surface and stormwater

management :

o Lake County contains extensive recharge areas for the Floridan

Aquifer (Figure 3-13). Therefore, recharge protection is

essential for potable water supplies for the area (Section 3.0

provides further details on recommendations); and

o Discharges to groundwater via sinkholes in Karst areas and

discharges via drain wells can adversely impact the quality along

with saltwater intrusion zones of groundwater supplies.

Therefore, these types of areas have been evaluated as problem

areas in Section 2.0 and recommendations are contained in

Section 3.0.

o Major wells and springs have also been included in Figure 1-6 as

an indicator of locations for groundwater discharges and monitor

locations by the USGS.

3.11 INVENTORY OF MAJOR STORMWATER CONVEW4NCE STRUCTURES

Information on hydraulic facilities can be obtained from several sources.

Supporting data files to FEMA FIS reports are occasionally sources of

hydraulic parameters for those structures studied by FEMA. No such data

have been available to date for this study. An index for diagrams showing

size and location of stormwater structures has been obtained from the

Florida Department of Transportation for all state roads in Lake County.

Engineering plans and as-builts (e.g., subdivision plans) submitted to Lake

County are additional sources of hydraulic data that can be examined to

avoid excessive field surveying requirements.

om miles

24 1 25 1 26

LEGEND

Q SPRINGS

AREAS OF GENERALLY

AREAS OF LOW RECHARGE

AREAS O F MODERATE

7 MAJOR USGS WELLS

GROUNDWATER CHARACTERISTICS en wionmen to1 engineers, scientists,

planners, & monogemen t consultants CDM FIGURE 3-73

For this phase of the County's overall Stormter Management Program, CDM

and the Department of Public Maintenance Supervisors for Districts 1, 2,

and 3 performed extensive field confirmation of stormwater facilities

serving each major County road. These field surveys were limited to

culverts with a capacity equal to, or greater than, a 36" circular pipe.

Each facility was measured for diameter, height, or width and condition.

Appendix B contains a table listing these facilities (Stormwater Facility

Inventory). The table contains the listing of facilities by USGS

quadrangle, ID code (e.g., B04005 is facility 5 in sub-basin B04),

description, and maintenance entity. Field reconnaissance by CDM engineers

and County staff has provided, and will continue to provide, vital

information needed to analyze key hydraulic components of the primary

stomter management system.

4.0 STORMWATER MANAGEPENT REGULATIONS

This Section provides a description of the regulatory and intergovernmental

framework which should be considered to regulate and implement the Lake

County Stormwater Management Program.

LAKE COUNTY

The existing Lake County regulations are in the process of revision. The County's drafted Stomwater Management Ordinance will provide regulatory

guidelines and Design Standards for new development. The Ordinance Design Standards stress the following key features necessary for a sound

stomwater management system:

o Pollutant Abatement;

o Rechargemere Possible;

o Protection From Flooding; and

o Erosion Protection.

Lake County is also seeking delegation from the SJRWMD for some of its

current surface water management regulatory programs.

4.2 CITIES AND TOWNS

This section presents a comparison of existing stormwater management

ordinances and design standards for the cities and towns located within

Lake County with the County's proposed Stormwater Management Ordinance. Of the 14 cities and towns reviewed, none had a separate stormwater management

ordinance but addressed stormwater management issues in their subdivision

ordinances. The results of the comparison are summarized in Table 4-1.

TABLE 4-1

COMPARISON OF EXISTING STORMUAATER MANAGEMENT ORDINANCES AND DESIGN STANDARDS

C i t y o f Town o f Town o f C i t y o f Lake F r u i t l a n d C i t y o f C i t y o f C i t y o f C i t y o f Town o f Howey-in Lady Town o f C i t y o f C i t y o f b u n t C i t y o f C i t y o f

ORDINANCE/DESIGN STANDARDS County Park Groveland Mascotte Minneola U m a t i l l a A s t a t u l a t h e - H i l l s Lake b n t v e r d e Leesburg Tavares Dora E u s t l s Clermont

---- Stormwater Management Ordinance X

---- S u b d i v i s i o n Ord inance -

Design Standards X X X X X X X X X X X X X X

---- General X X X X X X X X X X X X X X -------- ----------- ----------- ---------- ---------- ---------- ---------- ----------- --------- ----------- ---------- --------- -----I--- --------- ---------. - P o l l u t i o n Abatement X X X X X X X -------- -.--------- -------I--- --.------- ---.------ ---------- --------.- ----------- --------- ----------- ---------- --------- --------- --------- ---------. - Recharge where P o s s i b l e X X X -------- ----------- ----------- ---------- ---------- ---------- ---------- ----------- --------- ----------- ---------- --------- --------- -------I- ---------.. - P r o t e c t i o n f r o m F l o o d i n g X X X X X X X X X X X X X X -------- ----------- ----------- ---------- ---------- ---------- ---------- ----------- --------- ----------- ---------- --------- --------- --------- ---------. - Eros ion C o n t r o l X X X X X X X

---- D i s p o s i t i o n o f S t o m w a t e r Runof f X X X X X X X X X X X X X X

---- Oevelopnent w i t h i n Areas o f Special f l o o d Hazard (100-year f l o o d ) X X X X X X X X X X

---- Design C r i t e r i a X X X X X X X X X X X X X -------- ----------- ----------- ---------- ---------- ---------- ---------- ----------- --------- ----------- ---------- --------- --------- --------- ---------. - Methods o f Computing Runof f

Volune and Peak Rate D ischarge X X -------- ----------- ----------- ---------- ---------- ---------- ---------- *---------- --------- ----------- ---------- --------- --------- --------- ---------.

- Oesign Storm (minimum) X X X X X X X X X X -------- ----------- ----------- ---------- ---------- ---------- --em------ ----------- .................... ---------- --------- --------- ----1-1-- -------.-. - Storm D i s t r i b u t i o n X -.------ ----------- ----------- ---------- ---------- ---------- ---------- -------.--- --------- ----------- -.-.------ --------- --------- --------- ---------. - D e t e n t l o n / R e t e n t l o n Pond

C r i t e r i a X X X X X X X -------- ----------- ----------- ---------- --------a- ---------- --.------- ----------- --------- ----------- ---------- -----.--- *-------- --------- --------- - Open Channels X X X X X X X X X X X I ----

TABLE 4-1 [cont inued)

COMPARISON OF EXISTING STORMWAATER MANAGEMENT ORDINANCES AND DESIGN STANDARDS

NOTES: ( 1 ) X - I tems covered t n County. C t t y , and Town Stormwater Ordtnances o r Destgn Standards.

( 2 ) Lake County 's r ev tew I s based on t h e t r d r a f t Stormwater Ordtnance.

4

ORDINANCEIDESIGN STANDARDS [cont tnued)

Hydraul t c Destgn C r t t e r t a

- Roadway (Pavement) Dratnage Design

- Storm Sewer Destgn

- Cu l ve r t Destgn

Stormwater Management Plan Requirements

- S t o r m a t e r Map

- Subsotl I n v e s t t g a t t o n

- Stormwater Ca l cu la t t ons

Proof o f Lega l l ope ra t t on E n t i t y El t g t b t l t t y

- Hmeowners. P rope r t y Owners. o r Master Assoc ta t t on

Condomtnium Assoc ia t i on

- Assocta t ton Requtrements

- Submt t ta l Var iances

Easements

Lake County

X ----*---

X 0.-*----

X -------- X

X ---.---- X

.--..-**

X ***---*-

X

X *-*----*

X ---.***-

X --**-*I-

X *--*--**

X -**-**I-

X

C i t y o f F r u t t l a n d Park

X --**-------

X ------*----

------*----

X *-*----.-*-

X --*-----***

0-.--****-*

X

---.--*--*-

--*-*--I-**

*I**-----**

*---**--*--

X --*.o***---

X

C t t y o f Groveland

X .-*--------

X .------*---

X *------*---

X

X --.*------*

X ---om-----*

-.*----**-*

X

X ----o*-*---

*------*--*

*------*-*I

-**----***-

X **-*-*****-

X

C t t y o f l h s c o t t e

X -.-------- X

---.--*-.- X

*--------*

X

X -----*----

X .----***--

X -**.--*--*

X

X --**----.-

---*-*----

-*-**-----

--*--*-t-*

X --..-*-I--

X

C i t y o f U inneo la

X -----*----

X -*----*--*

X ------***-

X

X .--.------ X

I.*-*-----

-*--1--.--

X

X .---I*---*

*-C--t-**O

.*---*--I-

*-------.-

X --.- --*--- X

C i t y o f U n a t l l l a

X ---.***---

X ..-*------

X *CII*IIII*

X

X ---------- X

-------*--

-*--*---t*

X

--*-----*-

-*-*-**--I

-o*--*II-I

----*---*-

X *-***----*

X

Town o f A s t a t u l a

X -.-*.**--*

X *-*--**---

X *-***-----

X

X ---*-----*

X -*---*-*-*

----*---*- X

X -*---.----

*-*---**I*

--------*-

--*-*----. X

--*-**--I

X

Town o f Lady l a k e

X *-**---.-

X ..-*..*-*

X --***----

X

X -------*-

X -----*-**

X --**-----

X

X -*-*----*

..**I-----

----.--*I

---.**.--

X ----- *--. X

Town o f Howey-In t h e - H i l l s

*-*-.------

O-***II...-

--**-------

-------**--

---*------*

-*-*----**-

----*----*-

-*--*..----

--------*--

--.-*-*I--*

---*I*-----

Town o f b n t v e r d e

X ----------- X ---...-.--- X

----*------

X

X --*---*-*--

X -*---.-----

----------- X

X ----*---.--

X *----.*.-*-

*-**-*-*--I

.**.-*,-I-*

X O-*l---.-*-

X

C t t y o f Leesburg

X .----*--.*

X .-..-*..-.

X ---------- X

X .----.---- X

-*--*-----

-----*----

X

-*-*------

-t--w.**--

.---*--*--

....-*. 0.0

X .*--**-I--

X

C i t y o f Tavares

X --.------ X ..---..-- X

---*-*---

X

X --*------

X -*--*----

X O I - I - - * I -

X

--.---.-- *e-*-.--.

--.-*-e*-

O-I*I-*--

X *---.*---

X

C i t y o f Mount Dora

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Important notes of interest are described below:

o The majority of the ordinances, though general in nature, included

a statement indicating that the improvements will be designed and

installed in accordance with the criteria of the Lake County

Pollution Central Department and the St. Johns River Water

Management District (SJRWMD).

o Pollution abatement was not explicitly addressed in several of the

ordinances.

o Groundwater recharge where possible was not explicitly adressed in

the majority of the ordinances.

o ~esign methodologies regarding computation of runoff, design

storms, storm distribution, and retention/detention pond criteria

were not explicitly addressed in several of the ordinances.

o Subsoil investigations were not explicitly required in several of

the ordinances.

o The majority of the ordinances required proof of legal/operation

entities to provide maintenance of the proposed improvements.

Specifics regarding the creation of homeowners associations, etc.

were not explicitly addressed.

In conclusion, the majority of the subdivision ordinances reviewed contain

basic information providing a foundation for development of a stomter

management ordinance. The municipalities should be encouraged to develop

and adopt ordinances, paralleling the requirements of the Lake County

Stomter Management Ordinance and the criteria of the St. Johns River

Water Management District to properly guide future development.

4.3 FEDERAL AND STATE

UNITED STATES ENVIROIWSlT& PROTECTION AGENCY

The USEPA was mandated by Congress through Section 405 of the Water Quality

~ c t of 1987 to promulgate a National Pollutant Discharge Elimination System

(NPDES) permitting program for municipal stormwater discharges. Since the

population of Lake County does not exceed 250,000, the County will not have

to apply for a NPDES permit in the first tier of application.

UNITED STATES AFUW CORPS OF ENGINEERS

The USACOE does not regulate stormwater management, but it does regulate

dredge-and-fill, as well as plan navigation and flood control projects.

Many of the early flood studies in Florida were conducted by the USACOE.

Close coordination with the Jacksonville District regarding dredge-and-fill

will be essential to implementing regional management alternatives.

FLORIDA DEPARTMENT OF ENVIRONMENTAL REGULATION

The FDER has historically regulated dredge-and-fill and stormwater

discharge quality under Chapters 17-3 (Water Quality), 17-4 (Permits),

17-12 (Dredge and Fill), 17-22 (Drinking Water), and 17-25 (Regulation of

Stormwater Discharge), Florida Administrative Code (FAC). FDER recently

delegated much of its stormwater discharge quality permitting and some

dredge-and-fill permitting to the St. Johns River Water Management District

( S m ) . FDER has also been delegated as the Surface Water Improvement

and Management (SWIM) administration agency (Chapter 17-43, FAC) which must

oversee and approve SWIM projects as proposed and implemented by the

various water management districts.

ST. JOHNS RIVER WATER MANAGEPENT DISTRICT

The SJRWMD is responsible for groundwater and storwater management under

FAC Chapters 40C-2 (Consumptive Use), 40C-3 (Well Construction), 40C-4 and

40C-40 (Management and Storage of Surface Waters, MSSW), 40C-5 (Artificial

Recharge), 40C-6 (Works of the District), 40C-41 (Surface Water Management

Basin Criteria), 40C-42 (Regulation of Stormwater Discharge), and 40C-43

(Silviculture). In addition, its responsibilities are being expanded to

regulate some dredge-and-fill permitting.

Since SJEiWMD has the most directly applicable jurisdiction, its criteria

and standards will often be used as the guidelines for conceptual planning

of both water quality and quantity improvements.

FLORIDA DEPARTMENT OF COMMUNITY AFFAIRS

The FDCA is the implementation agency for the State Comprehensive Plan

(Chapter 187, Florida Statutes). Chapter 9J-5, FAC, outlines local

comprehensive plan elements which are submitted to the FDCA after receiving

comments from the local regional planning council (Northeast Florida

Regional Planning Council).

The requirements of Chapter 95-5 are met or exceeded by water management

district and/or county requirements. Therefore, compliance with SJRWMD and

City regulations will ensure compliance with the local and state

comprehensive plan requirements.

FLORIDA DEPARTMENT OF TRANSPORTATION

The FDOT has traditionally been the highway construction, operation, and

maintenance agency in Florida. Recently, the FDOT has been delegated

stormwater permitting authority for stormwater discharges which impact

state or federal roadways.

It is often desirable to coordinate stormwater Capital Improvement Programs

with FDOT projects, where possible, since major stormwater management

infrastructure are often contained in FDOT projects.

FLORIDA DEPAR- OF NATURAL RESOURCES

The FDNR regulates activities on state sovereign lands up to the mean high

water line. This is often waterward of the SJRWMD 10-year flood elevation.

The DNR does not issue permits, but rather all~ws/grants permission to

trespass on public lands. The FDNR should be contacted regarding the

potential placement of facilities within the sovereign waters-of-the-state

if such a need arises to retrofit existing development to protect receiving

waters.

5.1 GENERAL

Water quality data are needed to document adverse impacts to

waterbodies/watercourses and flora/fauna. Stormwater generates non-point

source pollutant loads which can degrade water quality. Traditionally,

water quality data are collected in regular intervals (e.g., quarterly) to

record ambient conditions in a given location.

The Lake County Department of Environmental Services Pollution Control

Division maintains an extensive network of water quality monitoring

stations throughout the County. Within the Oklawaha River chain, 26 lake and river stations are sampled on approximately a quarterly basis. Within

the Palatlakaha River basin, 30 lake and river stations are monitored. The water quality monitoring data represents ambient conditions in a given

location. The majority of the nonpoint pollution loads that are discharged

into Lake County lakes are associated with stormwater runoff. Model loading

projections for existing land use condition in Lake County watersheds

indicate that more than 70 percent of the annual total-P and lead loads are transported by surface runoff. As urbanization increases, imperviousness

within the watersheds this proportion can also be expected to increase.

Storm event sampling should be considered as part of the Lake County

watershed monitoring program. Initially, only limited storm event sampling

may be feasible (e.g., one or two stations); however, as Lake County staff

gain experience with sampling methods and equipment the storm event

sampling program can be expanded.

The occurrence of stormwater runoff in a watershed is a random process,

therefore, development of reliable storm event water quality data requires

a more sophisticated sampling program than ambient baseflow water quality

assessments. When storm events occur, especially in Lake County watersheds

with short travel times, the peak loadings of pollutants in stormwater may

occur before personnel are able to arrive at a site and begin manual

sampling. For this reason, it is usually desirable to use automatic flow

monitoring and water quality sampling instruments. Manual sampling has the

advantages of lower costs, simplicity, and more flexibility. However, these advantages are more than outweighed by the potential for failure to

obtain data when storm events occur. CDMrs experience with nonpoint source

monitoring has shown that a wet weather sampling program incorporating

automatic monitoring equipment will have the best chance for success. As part of EPArs upcoming NPDES permitting program for stomwater discharges

sampling of storm events at 5 to 10 outfalls will be required.

Storm event monitoring can be used to document the effectiveness of a

stormwater management plan in improving water quality. The primary purpose

of a stormwater monitoring program is to provide baseline data and to

evaluate future water quality trends (e.g., improving versus deteriorating

conditions).

5.2 BEST MANAG- PRACTICES (BMPs)

Best Management Practices (BMPs) are techniques, approaches, or designs

which promote sound use and protection of natural resources. Various types

of BMPs are discussed extensively in Chapter 6 of the FDER Land Development

Manual, 1989. The following BMPs are being applied in Lake County:

NON-STRUCTURAL SOURCE CONTROLS

Fertilizer Application Control

Pesticide Use Control

Solid Waste Collection and Disposal

Source Control on Construction Sites

Stormwater Management Ordinance Requirements

STRUCTURAL STORMWATER CONTROLS

Concrete Grid and Modular Pavement

Detention Basins (Wet and Dry)

Exfiltration Trenches

Grassed Waterways and Swales

Parking Lot Storage

Porous Asphalt Pavement

Retention Basins

Rooftop Runoff Disposal

Storageflreatment Facilities (e.g., oil and grease skimmers)

Underdrains and Stormwater Filter Systems

EROSION AND SEDIMENT CONTROL PRACTICES

Erosion and sediment control practices are addressed in the Draft Lake-

County Stormwater Management Ordinance by CDM.

All of these practices are important in the sound management of water

resources in the County. For stormwater quality enhancement applications,

the following sections discuss the relative merits of structural BMPs.

5.2.1 STRUCTURAL BMP ALTERNATIVES

The structural BMPs screened for applications in Lake County were:

Infiltration Controls: These BMPs are also referred to as

"stormwater retention" controls. They divert stormwater runoff

into the soil profile where pollutant removal can occur as a

result of natural "treatment" processes such as filtration,

adsorption, and oxidation by soil microorganisms. Examples

include: infiltration/retention basins and trenches, swales,

exfiltration systems, underdrains, dry wells, and porous and

modular pavement.

2. Detention Controls: These BMPs achieve removal of suspended

pollutants through sedimentation processes and, in the case of wet

detention basins, the removal of dissolved pollutants through

physical, chemical, and biological processes within the basin's

permanent pool. Examples of these are dry and wet detention

ponds.

5.2.2 COMPARISON OF STRUCTURAL BMPs

Except for swales, infiltration BMPs require much more frequent maintenance

and major cleanouts than detention basin BMPs (CDM, 1985). Infiltration

BMPs tend to require major cleanouts nearly every year or so to eliminate

clogging conditions. In the absence of an intensive, continuing

maintenance program, these BMPs will tend to fail within a few years after

start-up. In addition, because infiltration BMPs require highly permeable

soils which are not restricted by a high water table, these devices will be

limited to those sections of the study area based on case-by-case

applications (e.g., with Class A soils and a low water table). However, retention controls can be very effective where such suitable conditions

exist, and these are recommended for new recharge requirements on

hydrologic group A soils that the County is considering in their draft

Stormwater Management Ordinance. In addition, retention BMPs provide high

levels of pollutant removal from surface waater discharges, although

soluble pollutants are ultimately discharged to the groundwater. Where infiltration BMPs are used for surface water quality protection, a storage

volume requirement of 0.5 inch of runoff per impervious acre is the most

appropriate design standard (CDM, 1985).

Two different detention basin BMPs are currently used for runoff pollution

control: wet detention and extended dry detention. In wet detention

basins, pollutant removal occurs primarily within a permanent pool during

the period of time between storm events. The "extended dry" method

provides increased detention times for captured first-flush runoff in order

to enhance solids settling and the removal of suspended pollutants.

In comparison with extended dry detention basins, wet detention basin BMPs

offer the advantage of pollution removal mechanisms for dissolved

phosphorus and dissolved nitrogen. Whereas dry detention systems can only

rely upon solids settling processes for phosphorus and nitrogen removal,

wet detention can achieve removal of dissolved nutrients through other

physical/chemical and biological processes in the permanent pool (e.g.,

uptake of nutrients by free-floating algae and wetland vegetation around

the edge of the pool). ~s a result, monitored average pollutant removal

efficiencies (USEPA, 1983; NVPDC, 1983) for wet detention basin BMPs are on

the order of 2 to 3 times greater than extended dry detention BMPs in the

case of total-P (50-60 percent vs. 20-30 percent) and 1.3 to 2 times

greater in the case of total-N (30-40 percent vs. 20-30 percent). The

increased removal rates for total-P and total-N in wet detention basins can

be attributed in large part to average removal rates on the order of 50-70 percent for dissolved nutrients, the nutrient fraction that is most readily

available for biological activity and of greatest interest from a water

quality management standpoint. Urban non-point pollution monitoring

studies in northern Virginia found that dissolved nutrient fractions

represented up to 60 percent or more of total-P and up to 80 percent or

more of total-N (NVPDC, 1983).

For other pollutants, the average removal rates for wet detention basins

and extended dry detention basins are very similar (USEPA, 1983; NVPDC,

1983): 80-90 percent for total suspended solids; 70-80 percent for lead;

40-50 percent for zinc; and 20-40 percent for BOD or COD. The efficiencies

for extended dry detention basins are based on an average hydraulic

residence time of 2 weeks or greater for permanent pool of wet detention

basin, and 12-24 hr detention time for extended dry detention basin with a

storage capacity of 1.0 inches of runoff per impervious acre. The major

difference between the performance of wet and dry detention basins is the

greater removal of nutrients in the former, therefore wet detention basins

are more appropriate than extended dry detention basins for areas where the

receiving water quality problems are caused by nutrient loadings.

A schematic diagram of a wet detention basin is shown in Figure 5-1. As

may be seen, the facility consists of a permanent storage pool (i.e.,

section of the pond which holds water at all times) and an overlying zone

of temporary storage to accommodate increases in the depth of water

resulting from runoff. As shown in Figure 5-1, pollutant removal within

the wet detention basin can be attributed to the following important

pollutant removal processes which occur within the permanent pool: uptake

of nutrients by algae and rooted aquatic plants; adsorption of nutrients

and heavy metals onto bottom sediments; biological oxidation of organic

materials; and sedimentation of suspended solids and attached pollutants.

Uptake by algae and rooted aquatic plants is probably the most important process for the removal of nutrients. Sedimentation and adsorption onto

bottom sediments is probably the most important removal mechanism for heavy

metals. Aerobic conditions at the bottom of the permanent pool will

maximize the uptake of phosphorus and heavy metals by bottom sediments and minimize pollutant releases from the sediments into the &ter column.

Since ponds that exhibit thermal stratification (i.e., separation of the

permanent pool into an upper layer of high temperature and a lower layer of

low temperature) are likely to exhibit anaerobic bottom waters during the

summer months, relatively shallow permanent pools that maximize vertical

mixing are preferable to relatively deep basins.

Wet detention basin BMPs do offer some other advantages which should be considered in BMP selection. Wet detention basins are usually more

attractive looking than dry basins, particularly if there is extensive

wetland vegetation around the perimeter of the permanent pool. When

properly designed and constructed, wet detention basins are actually

considered as property value amenities in many areas. Also, wet detention

basins offer the advantage that sediment and debris accumulate within the

permanent pool. Since these accumulations are out-of-sight and well below

the basin outlet, wet detention basins tend to require less frequent

cleanouts to maintain an attractive appearance and prevent clogging.

If the contributing area is too small, storm runoff and dry weather inflows

into the wet detention basin may be too small to maintain a permanent pool

during "dry" seasons. While excessive drawdown of the permanent pool does

not pose a non-point pollution control problem, it will cause aesthetic

problems. Suggested guidelines for minimum contributing areas of wet

detention basins are presented later in this section.

The potential impacts of stormwater management structures on wetlands are

addressed and monitored by the FDER. While it can be argued that wet

detention basins can be designed to produce new wetland systems and that

the additional water quality protection justifies potential wetlands

impacts, extreme care and precautions must be exercised where stormwater

treatment is provided through the use of existing wetlands.

5.2.3 DESIGN CRITERIA FOR PREFERRED STRUCTURAL BMPs

The most important feature of a wet detention basin is the permanent pool.

Urban runoff detained in the permanent pool following a storm event is

subjected to physical/chemical and biological processes which achieve

removal of selected pollutants. During the next storm event, urban runoff

inflows displace "treated" waters in the permanent pool followed by

treatment after the storm ends. This means that the size and shape of the

permanent pool is an important design criterion. For example, the larger

the permanent pool storage volume in comparison with design runoff

conditions (e.g., first 1.0 inch of runoff), the lower the outflow of urban

runoff inflows and the higher the retention and treatment between

rainstorms. Two different methods are available for design of wet

detention basins: (1) solids settling design method; and (2) lake

eutrophication model design method.

Solids Settling Design Method

The solids settling design method (Driscoll, 1983) relies upon

rainfall/runoff statistics, settling velocities for assumed particle size

distributions, and the assumed percentage of pollutant mass attached to

sediment (particulate fraction) in order to calculate suspended pollutant

removal for specified overflow rates. Separate efficiency calculations for

dynamic conditions during storm events and for quiescent conditions

following storm events are weighted by the duration of each condition to

determine a long-term average pollutant removal rate. The method assumes

an approximate plug flow system in the detention basin, with all pollutant

removal resulting from Type I sedimentation. While this assumption may be

reasonable for dynamic conditions during storm events, completely mixed

conditions which account for longitudinal dispersion may be more likely

under quiescent conditions. Pollutant removal under quiescent conditions

is based upon a capture/pumpout model originally developed for evaluations

of combined sewer overflow (CSO) interceptors. For permanent pool storage

volumes typically considered for wet detention basins, the solids settling

method usually assigns more than 90 percent of the total pollutant removal

to quiescent conditions and less than 10 percent to the dynamic conditions

which are probably best represented by the plug flow assumptions of the

design model.

Design curves for the solids settling method for wet detention basin design

are shown in Figure 5-2. As may be seen, these curves relate average TSS

removal to the size of the permanent pool. For these particular design

curves, the permanent pool size is expressed in terms of the ratio of its

surface area to the BMP contributing area. Since these curves are based

upon a mean depth of 3.5 ft for the permanent pool, the x-axis can easily

be converted to a permanent pool storage volume (i.e., product of surface

area and mean depth).

This design method is most appropriate for handling suspended solids and

constituents such as heavy metals (e.g., lead) which tend to appear

primarily in suspended form, since sedimentation should be the dominant

pollutant removal process. However, it is less appropriate for the

evaluation of nutrient removal efficiencies since monitoring data at

several NURP wet detention basin sites indicate that the majority of

total-P and/or total-N mass removal was in the form of dissolved P and

dissolved N. This is illustrated in Table 5-1 which summarizes average

removal of total-P and dissolved P monitored at the NURP wet detention

basin sites and other testing sites. As may be seen, dissolved P removal

represents a major component of total-P removal at seven of the ten sites

which reported dissolved P removal rates. For example, the portion of the

total-P efficiency attributable to dissolved P removal ranged from 62

percent to 8 percent for four of the NURP sites. This suggests that solids

TABLE 5-1

MONITORED WET DETENTION BASIN EFFICIENCIES TOTAL-P AND DISSOLVED P SUMMARY

Location

A. NURP

Ladsing, MI Lansing, MI Ann Arbor, MI Ann Arbor, MI Ann Arbor, MI Long Island, NY Washington, DC Washington, DC Glen Ellyn, IL Lansing, MI

Aver age Dissolved P Hydraulic Average Average Fraction of Residence Total-P Dissolved P Total-P Time Removal Removal Removal

Site (weeks) ( % I ( % I ( % I

Grace N. Grace S. Pitt Swift Run Traver Ungua Burke Westleigh Lake Ellyn Waverly Hills

B. USGS (1986)

Orlando FL Highway Pond 1-2 29% 54% 63%

C. Minnesota

TwinCities,MN Fish 5 44% 32% 47% Roseville, MN Josephine 6 62% 69% 75%

SOURCE: Walker, 1987

settling theory alone does not account for the most important nutrient

removal mechanisms in wet detention basin BMPs.

Lake Eutrophication Model Design Method

This approach assumes that a wet detention basin BMP is a small eutrophic

lake which can be represented by empirical models used to evaluate lake

eutrophication impacts (Walker, 1987; Hartigan, 1988). The intent of

this approach is to use lake eutrophication models to account for the

significant removal of dissolved nutrients observed in the field and

attributable to biological processes such as uptake by algae and rooted

aquatic vegetation. Using this design method, a wet detention basin can be

sized to achieve a controlled rate of eutrophication and an associated

removal rate for nutrients.

The design method is restricted to nutrients. However, since wet detention basin BMPs that achieve significant nutrient removal also achieve removal

rates for other pollutants that are similar to other BMPs, it is probably

not necessary for the design method to address other constituents besides

nutrients. Likewise, wet detention basin BMPs may not be cost-effective

unless nutrient control is the principal water quality management

objective.

The recommended lake eutrophication design model is the phosphorus

retention coefficient model developed by Walker (1987). Like most

input/output lake eutrophication models, this model is an empirical '

approach which treats the permanent pool as a completely mixed system and

assumes that it is not necessary to consider the temporal variability

associated with individual storm events. Unlike the solids settling model

which accounts for temporal variability of individual storms, the Walker

model is based upon annual flows and loadings. Because it does not

consider storm to storm variability, this model is much simpler to apply

than the solids settling model.

To test how well the model represents wet detention basin B ~ s , Walker

(1987) applied it to 10 NURP sites and 14 other wet detention systems and

small lakes. The goodness-of-fit assessments yielded an R~ of about 0.8,

indicating that the model does a good job of replicating monitored average

total-P removal from detention basin design characteristics.

5.2.4 POLLUTANT REMOVAL EFFICIENCIES

Based upon NURP monitoring studies of BMPs, the following average pollutant

removal efficiencies are often used in evaluating wet detention basin BMPS:

o Total P: 50 percent

o Total N: 30 percent

o Lead: 80 percent

o Zinc: 70 percent

These average annual efficiencies are consistent with design criteria for

wet detention basins.

5.3 REGIONAL VS. ONSITE DEPLOYMENT OF STRUCTURAL BMPs

ADVANTAGES OF REGIONAL APPROACH

Figure 5-3 illustrates the two different approaches that can be taken for

deployment of structural BMPs for watershed protection:

Onsite Approach: In the case of future urban development, this

option involves the delegation of responsibilities for BMP

deployment to local land developers. Each developer is

responsible for constructing a structural BMP(s) at his develop

ment site to control non-point pollution loadings from the site.

Detention basin BMPs provided onsite typically have drainage areas

of 20-50 acres. The local government is responsible for reviewing

each structural BMP design to ensure conformance with specified

design criteria, for inspecting the constructed facility to ensure

0 Z V) - --I m < In 2J m !2 0 Z > I-

CD I 73

b, 9 . a 2 3 $ !+; 3 - 2 " 8 9 $ 3 2? 8, 2 2 s g 3 % 2 .:

ONSITE (Each developer provides BMP on development sile)

REGIONAL (Strategically located by local government)

I

I

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,

ALTERNATIVES FOR BMP DEPLOYMENT I I

-- -

conformance with the design, and for ensuring that a maintenance

plan is implemented for the facility.

2. Regional Approach: This option involves strategically siting

regional structural BMPs to control non-point pollution loadings

from multiple development projects. The front-end costs for

constructing the structural BMP are assumed by the local

government which administers the regional BMP plan. BMP capital

costs are then recovered from upstream developers on a "pro-ratall

basis as development occurs. Individual regional BMPs are phased

in as development occurs rather than constructing all regional

facilities at one time. Maintenance responsibility for regional

structural BMPs is generally assumed by the local government.

In developing stomter and watershed management programs during the

1970fs, local governments often elected to use the piecemeal approach

because it required no advanced planning and, therefore, it appeared

relatively easy to administer. While the lack of planning requirements

does give this approach an advantage in comparison with the comprehensive

approach, the disadvantages far outweigh this benefit.

A regional BMP system offers benefits which are equal to or greater than

onsite BMP benefits at a lower cost. Most of the advantages of the

regional approach over the onsite.approach can be attributed to the need

for fewer structural facilities which are strategically located within the

watershed. The specific advantages of the regional approach are summarized

below:

o Reduction in capital costs for structural BMPs: The use of a

single stormwater detention facility to control runoff from 5 to

15 development sites within a 500-1,000 acre subwatershed permits

the local government to take advantage of economies-of-scale in

designing and constructing the regional facility. In other words,

the total capital cost (e.g., construction, land acquisition,

engineering design) of several small onsite detention BMPs is

greater than the cost of a single regional detention basin BMP which provides the same total storage volume.

o Reduction in maintenance costs: Since there are fewer stomwater

detention facilities to maintain, the annual cost of maintenance

programs are significantly lower. Moreover, since the regional

detention facility recommended in the master plan can be designed

to facilitate maintenance activities, annual maintenance costs are

further reduced in comparison with onsite facilities. Examples of

design features that are typically only feasible at regional BMP

facilities to reduce maintenance costs include: access roads that

facilitate the movement of equipment and work crews onto the site

(by comparison, detention facilities implemented under the onsite approach are often located in residential backyards); additional

sediment storage capacity (e.g., sediment forebay) to permit an

increase in the time interval between facility clean-out

operations; and onsite disposal areas for sediment and debris

removed during clean-out.

o Greater reliability: The bottom line is that a regional BMP

system will be more reliable than an onsite BMP system because it

will be more likely to be maintained. With fewer facilities to

maintain and design features which reduce maintenance costs, the

regional BMP approach is much more likely to result in an

effective long-term maintenance program. Due to the greater

number of facilities, the onsite BMP approach tends to result in a

large number of facilities which do not get adequately maintained

and therefore soon cease to function as designed. Most cities and

counties who start off with the onsite approach eventually switch

to the regional approach to address the lack of maintenance of the

onsite systems and to increase the overall effectiveness of the

stomter management program. Good examples are Fairfax County,

Virginia, and Montgomery County, Maryland, where problems with the

effectiveness of an onsite stormwater control approach eventually

led to the implementation of a regional approach.

o Opportunities to manage existing non-point pollution loadings:

b on-point pollution loadings from existing developed areas can be

affordably controlled at the same regional facilities which are

sited to control future urban development. This is because the provision of additional storage capacity to control runoff from

existing development in the facility's drainage area should be

relatively inexpensive due to economies-of-scale. BY comparison,

the costs of retrofitting existing development sites with onsite

detention BMPs to control existing non-point pollution loadings

would probably be prohibitively expensive.

o Fair to land developers: Land developers recognize that

economies-of-scale available at a single regional BMP facility

should produce lower capital costs in comparison with several

onsite detention facilities. They also tend to prefer the

regional BMP approach because it eliminates the need to set aside

acreage for an onsite facility, and therefore could permit an

increase in the number of dwelling units within the development

site.

o Multi-purpose uses: Regional facilities can often be landscaped

to offer recreational and aesthetic benefits. Jogging and walking

trails, picnic areas, ballfields, and canoeing or boating are some

of the typical uses. For example, portions of the facility used

for flood control can be kept dry, except during floods, and can

be used for soccer or football fields. Wildlife benefits can also

be enhanced in the form of islands or preservation zones which

allow a view of nature within the park schemes. Figure 5-4 shows

a profile view of a typical multi-purpose facility. Gradual

swales can also be worked into the park concept to provide

pre-treatment around paved areas, such as parking lots.

Figure 5-5 shows a typical swale detail.

NOTES:

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B 2 3 q 5. .'" 9 P; 3, 2 % 2 2 4 '2. 4 a - 7

0 -'"

2 8 2 2 2 2 2 2 G; S

I . SLOPES SHALL BE NO STEEPER THAN 4H: I V AND 6H: I V IS PREFERRED.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " "

GROUNDWATER TABLE -:--^-----------------7----,------ --3-,-----------------------A*-------.

. . . . . . . . . . . . ......... .......... .................................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .: :.: .:.. :',:, .:.:,.:.:..:.:. .:.:.:'.:..: :.: 7...'.....',.,., .................................................................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ) :.. :.. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ...:..... *. ................................................................................................. . . , . , . , . , . , . , . . . . . . . :;,:.;:.:...:. ....:. ....:. s:.:. .::, .:::.:. .:.:. .:.;..:.:::.:. .:.:. ~;.~~::.;:::. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : .

2. SWALE INVERT SHALL BE AT LEAST 1-2 FEET ABOVE THE SEASONAL HIGH WATER TABLE.

3. SWALES SHALL BE GRASSED AND CHECK DAMS PLACED AS NEEDED TO CONTROL OVERFLOWS AND VELOCITIES. '

5.4 WATER OUALITY EVALUATIONS

This section presents an evaluation of water quality within selected lakes

and rivers within Lake County. The evaluation is based upon available

historical monitoring data compiled by the Lake County Department of

Environmental Services, Pollution Control Division during the period 1985

through the first quarter of 1990.

5.4.1 MISTING LAKE COUNTY MONITORING

Lake County has been monitoring ambient conditions within lakes and streams

for more than five years. Samples have been collected approximately on a

quarterly basis and analyses are performed for the following parameters:

PARAMETER

Secchi Depth (field) Temperature (field) Dissolved Oxygen (field) pH (field Specific Conductance (field) Phenol Alkalinity Methyl Alkalini ty Chlorides Ammonia-N Organi c-N Nitrate+Nitrite-N Total Phosphorus Orthophosphate Biochemical Oxygen Demand Turbidity Total Suspended Solids Chlorophyll-a

ABBREVIATION

SECCHI TEMP D.O. PH COND P-ALK M-ALK C G NH4-N ORGN NOX-N Total-P Or tho-P BOD-5 TURB. TSS CHLOR-a

UNITS

meters deg. C mgfi Stan. Units uhmos/cm mgfi mgfi mgfi mgfi mgfi mgfi mgfi mgfi mgfi NTU mgfi ugfi

~ o t all analyses are performed on every sample. Some parameters have been intermittently dropped or performed on irregular intervals. The water quality monitoring data are entered into a spreadsheet database which is

kept up to date. The database also includes the time and date of sample

collection and the water column depth that the sample was collected from.

In general, field parameters are recorded at the surface or at 0.3 meters.

Laboratory analyses are performed on samples collected at one half of the

total depth at the sampling station. Chlorophyll-a samples are collected

from one half the secchi depth or 0.3 meters whichever is greater.

CDM obtained copies of the available water quality monitoring data for the

period 1985 to present from the Lake County Department of Environmental

Services. Water quality monitoring data are available for eleven of the

twelve lakes selected for stomwater pollutant loading evaluations. The

eleven lakes include; Lake Beauclair, Lake Dora, Lake Harris, Little Lake

Harris, Lake Louisa, Lake Mimehaha, Lake Mimeola, and Lake Yale. Lake

Carlton is the only lake included in the stomwater pollutant loading

analyses for which no water quality monitoring data were obtained.

Summary statistics for each of the study area lakes is presented in

Table 5-2. Mean, maxim, and minim values as well as the number of

samples (N) are summarized for selected pollutant parameters. These mean

concentrations are shown graphically in Figures 5-6 through 5-9 for

total-P, total-N, secchi depth, and chlorophyll-a. Within Lake Beauclair,

average concentrations of total-P are in excess of 0.20 mgfi Average

total-N concentrations in Lake Beauclair are almost 4.0 mgfi. High average

total-P concentrations are reported for Lake Dora and Lake Griffin.

Average total-N concentrations in Lake Dora and Lake Griffin are greater

than 3.0 mgfi

Chlorophyll-a, a pigment that is present in all types of algae, is a common

indicator of nutrient enrichment and eutrophication in a lake. Analysis of

chlorophyll-a is often used to assess the biomass present in a lake.

Chlorophyll-a concentrations greater than 20 ugfi are generally considered

indicative of eutrophic conditions within a lake. Average chlorophyll-a

concentrations reported within Lake Beauclair is more than six times this

threshold at 120 ugfi. Average chlorophyll-a concentrations reported

within Lake Dora is about 110 ugh. Chlorophyll-a concentrations ranging

from about 35 ugfi to 70 ugfi which are also indicative of eutrophic

conditions, are observed in lake Eustis, Lake Griffin, Lake Harris, and

Little Lake Harris.

TABLE 5-2

SUMMARY OF LAKE WATER QUALITY MONITORING DATA SOURCE: Lake County Dept. of Environmental Services

LAKE BEAUCLAIR SECCHI TEMP D.O. pH COND M-ALK CL- NH4-N ORG-N NOx-N TOTAL-P BOD5 TURB. CHLOR-a

I m l O W l S U l ~ ~ m ( m a / L I I m a / L I m m m m UlU Mean 0.32 23.4 9.6 8.9 369 114 40.8 0.14 3.72 0.04 0.21 7.6 12.3 121.2 N 15 15 15 15 15 16 16 13 15 10 15 13 13 13 Max 0.50 31 .O 14.2 9.4 424 132 45.5 0.36 5.02 0.27 0.33 13.4 22.5 214.5 Min 0.2 15.0 5 8.3 31 0 80 36.5 0.02 1.94 0.01 0.08 0 6 22 LAKE CHERRY

SECCHI TEMP D.O. pH COND M-ALK CL- NH4-N ORG-N NOx-N TOTAL-P BOD5 TURB. CHLOR-a I m l L d e a C ) w lSUllumtmmmWmm m m m lualU

Mean 2.00 25.2 7.3 6.5 96 5 21.2 0.08 0.53 0.01 0.012 1.9 1.2 3.84 N 24 25 25 25 25 25 25 17 24 1 18 6 25 19 Max 3.00 33.0 9.5 7.5 118 11 40.5 0.20 0.70 0.01 0.03 4.2 2.3 12.0 Min 1.25 16.7 4.9 5.5 75 3 16.5 0.02 0.34 0.01 0.01 1.2 0.8 0.8 LAKE DORA

SECCHl TEMP D.O. pH COND M-ALK CL- NH4-N ORG-N NOx-N TOTAL-P BOD5 TURB. CHLOR-a m(deaCI0 w o I m a R ) l m a R l w I m a / L ) m Iman)(maR)INTU) lua/U

Mean 0.31 23.6 9.5 8.6 372 119 39.8 0.18 3.56 0.02 0.14 7.5 11.1 106.7 N 28 28 28 28 27 30 30 30 30 15 28 28 28 29 Max 0.60 30.0 14.8 9.5 438 138 45.5 0.58 4.38 0.03 0.38 12.5 26.0 188.4 Min 0.25 16.0 5.6 7.8 190 92 22.0 0.02 2.06 0.01 0.05 4.3 6.2 11.4 LAKE EUSTIS

SECCHI TEMP D.O. pH COND M-ALK CL- NH4-N ORG-N NOx-N TOTAL-P BOD5 TURB. CHLOR-a m f ! & m m w o m t m a R ) ( m a R I I m a / L ) I m a / L ) l m a R l o I N T U ) (urJ/U

Mean 0.56 23.5 8.9 8.3 314 104 30.8 0.19 2.14 0.02 0.05 3.6 7.5 45.0 N 30 30 30 30 30 30 30 30 30 11 30 30 28 29 Max 1.10 30.7 12.2 9.3 363 120 38.0 0.88 3.08 0.08 0.08 6.0 16.0 120.3 Min 0.3 16.0 4.6 7.4 230 88 25.0 0.02 1.20 0.01 0.03 1.6 3.5 10

TABLE 5-2 (Cont . )

SUMMARY OF LAKE WATER QUALITY MONITORING DATA SOURCE: Lake County Dept. of Environmental Services.

LAKE GRIFFIN SECCHI TEMP D.O. pH COND M-ALK CL- NH4-N ORG-N NOX-N TOTAL-P BOD5 TURB. CHLOR-a

ltnl(deslCItmaRl W f m ! m ( m a R ) m m m w l m a R l ~ ( N T U ) (ua/LI Mean 0.46 23.1 8.5 8.3 325 106 31.1 0.23 2.92 0.02 0.08 6.5 12.4 69.5 N 58 58 -58 58 57 57 57 53 56 26 58 58 52 56 Max 1.7 30.1 12.1 9 .O 400 129 39.5 1.08 6.16 0.10 0.32 78.3 24.0 196.0 Min 0.25 15.0 5.1 7.1 250 0 0.0 0.01 1.30 0.01 0.02 0.0 2.8 4.0 LAKE HARRIS

SECCHI TEMP D.O. pH COND M-ALK CL- NH4-N ORG-N NOx-N TOTAL-P BOD5 TURB. CHLOR-a

m(deaCIImalLI W l u m h o s l ~ ~ ~ ~ I m a R ) w m m Lua/U Mean 0.65 23.8 8.9 8.3 246 91 22.2 0.13 1.59 0.04 0.04 3.07 5.89 39.8 N 43 43 43 43 43 42 42 36 41 15 41 43 39 41 Max 1 .O 32.0 10.8 9.1 288 102 38.0 0.38 2.40 0.12 0.08 5.6 9.5 118.0 Min 0.3 16.0 4.8 7.6 1 80 77 19.0 0.02 0.50 0.01 0.01 1.3 4.2 6.0 LITTLE LAKE HARRIS

SECCHI TEMP D.O. pH COND M-ALK CL- NH4-N ORG-N NOx-N TOTAL-P BOD5 TURB. CHLOR-a ma!aatmaRl W f m ! m I m a R ) m ( m a / L 1 I m a R l I m a R ) I m a R I O W lua/LI

Mean 0.70 23.9 9.0 8.2 240 89 21.1 0.17 1.50 0.05 0.04 3.1 5.7 34.3 N 28 28 28 28 28 28 28 28 27 12 28 28 26 28 Max 1.20 31.2 10.6 8.9 275 96 25.0 0.74 2.32 0.16 0.1 1 5.8 8.5 123.0 Min 0.4 15.0 6.4 6.7 180 79 15.5 0.00 0.08 0.01 0.01 0 3 4 LAKE LOUISA


m(deaCIImaR) Wlumhos)ImaR)lmanlImall)ImaR)ImalLI ImaR)wm LualL) Mean 0.90 24.7 7.8 5.8 83 5 18.0 0.12 0.70 0.14 0.03 1.2 1.7 6.9 N 28 28 28 28 28 28 28 27 28 20 28 8 28 23 Max 1.75 32.0 10.2 6.7 113 15 20.0 0.50 0.90 0.70 0.15 1.6 3.6 18.5 Min 0.5 16.4 6.1 4.7 60 1 14.5 0.02 0.07 0.01 0.01 1 1.1 1.5

TABLE 5-2 (Cont. )

SUMMARY OF LAKE WATER QUALITY MONITORING DATA SOURCE: Lake County Dept. of Environmental Services

LAKE MINNEHAHA SECCHl TEMP D.O. pH COND M-ALK CL- NH4-N ORG-N NOx-N TOTAL-P BOD5 TURB. CHLOR-a

I m l ~ ( m a R 1 wLumhosltma/L)ImalLIIma/L1(maRIImaRl m o m w Mean 1.64 24.7 7.6 6.3 87 5 18.9 0.07 0.54 0.11 0.02 1.2 1.7 3.7 N 28 28 28 28 28 28 28 22 28 6 21 6 28 2 1 Max 3.25 31.1 10.6 7.5 116 14 22.5 0.30 0.80 0.13 0.02 1.4 2.6 8.0 Min 1 16.4 5.5 5.2 70 3 16.0 0.02 0.14 0.09 0.01 1 1 1 LAKE MINNEOLA


Iml(deaCIma4 L S U l l u m h o s l m w m m I m a R ) 0 w I N T U ) lualU Mean 2.22 24.8 7.5 6.5 93 5 19.9 0.13 0.48 0.02 0.04 1.43 1.55 4.8 N 40 40 40 40 40 39 39 34 40 5 33 10 40 25 Max 5.3 33.0 9.7 8.3 122 12 22.5 0.74 1.10 0.06 0.72 2.7 2.4 20.0 Min 0.75 16.4 4.7 5.2 70 2 17.0 0.00 0.06 0.01 0.01 1 0.74 0.8 LAKE YALE

SECCHI TEMP D.O. pH COND M-ALK CL- NH4-N ORG-N NOx-N TOTAL-P BOD5 TURB. CHLOR-a mh!a-QImah) w-wmmm(maRI ~~m IudLl

Mean 1.8 23.6 8.6 8.1 298 107 31.8 0.14 0.83 0.03 0.02 2.1 2.6 12.4 N 28 28 28 28 27 28 27 22 30 2 27 21 30 21 Max 3.5 29.7 10.6 8.8 338 120 35.0 0.74 1.22 0.03 0.03 8.5 13.0 28.1 Min 1.0 16.0 6.5 7 240 93 28.0 0.02 0.50 0.02 0.01 1 0 1

MEAN CONCENTRATION 1985-1 990: TOTAL-P LAKE COUNTY MONITORING DATA

LAKE

MEAN CONCENTRATION 1985-1990: TOTAL-N LAKE COUNTY MONITORING DATA

LAKE

MEAN CONCENTRATION 1985-1990: SECCHI LAKE COUNTY MONITORING DATA

BEAUCLAIR CHERRY CARLTON

I

HARRIS LOUISA L. HARRIS MlNNEHAHA DORA YALE

LAKE

MEAN CONCENTRATION 1985-1 990: CHL-A LAKE COUNTY MONITORING DATA

Secchi depth is a measure of the transparency of waters in a lake. The measured Secchi depth tends to decrease as water quality deteriorates.

Secchi depths less than 1.0 meter have been correlated to eutrophic

conditions in a lake. As shown in Figure 5-9, seven of the study area

lakes exhibit average secchi disks depths less than 1.0 meter.

5.4.2 TROPHIC STATE INDEX

A preliminary Trophic State Index (TSI) was applied to the eleven study

area lakes for which water quality monitoring data was available. The TSI procedure provides an effective method of classifying lakes based on the

lakesf chlorophyll-a, Secchi depth, nitrogen and phosphorus concentrations.

The Florida Trophic State Index was developed in 1982 in response to the

EPA Clean Lakes Program. The index is based on a trophic state classifica-

tion developed in 1977 by R. E. Carlson. Criteria were developed for

Florida lakes from a regression analysis of data on 213 Florida lakes. The

desirable upper limit for the index is set at 20 ugfi chlorophyll-a which

corresponds to an index of 60. Doubling the chlorophyll concentration to 40

ugfi results in an index increase to 70 which is the cutoff for undesirable

(or poor) lake quality.

A nutrient index is calculated based upon phosphorus and nitrogen

concentration and the limiting nutrient concept. The limiting nutrient

concept identifies a lake as phosphorus limited if the nitrogen to

phosphorus concentration ratio is greater than 30, as nitrogen limited if

the ratio is less than 10 and balanced (depending on both nitrogen and

phosphorus) if the ratio is between 10 and 30. The nutrient TSI is based

solely on phosphorus if the ratio is greater than 30, solely on nitrogen it

the ratio is less than 10 and an average of the nitrogen and phosphorus TSI

if the ratio is between 10 and 30.

An overall TSI is calculated based on the average of the chlorophyll-a TSI,

the Secchi TSI, and the nutrient TSI. The criteria which have been

established for the Florida TSI are:

TSI Water Quality Indicator

Good Fair Poor

For each of the study area lakes, a TSI was calculated from the statistical

summaries of the available Lake County water quality monitoring data. The

TSI results are presented in Table 5-3. TSI values are presented for

average Secchi depth, nutrient, and chlorophyll-a. In addition, ratios of

average nitrogen to phosphorus concentrations are presented. Eight of the

selected study area lakes appear to be phosphorus limited (TN:TP>30) while

three lakes are balanced (10<TN:TP<30). Results of the TSI analysis are

also presented in Table 5-3. Lake Beauclair, Lake Dora, and Lake Griffin

have TSI values indicative of "poor1' water quality. The TSI value for Lake

Eustis is borderline fair to poor. Both Lake Harris and Little Lake Harris

have TSI values indicative of "fair" water quality. The TSI values for

Lake Cherry, Lake Louisa, Lake Minnehaha, Lake Minneola and Lake Yale are

indicative of "good1' water quality.

5.4.3 STOFtMWATER POLLUTANT LOADINGS

A preliminary evaluation of non-point pollution loadings was performed in

order to assess general areawide trends and to provide a framework for more

detailed analyses to be performed under the Lake County Stormwater Master

Plan. The non-point pollution loading analyses provides estimates of the

mass loadings (i.e., pounds per year) of pollutants from sub-basins

discharging to the following lakes: Lake Beauclair, Lake Carlton, Lake

Cherry, Lake Dora, Lake Eustis, Lake Harris, Little Lake Harris, Lake

Griffin, Lake Minneola, Lake Minnehaha, Lake Louisa, and Lake Yale.

pollutant load projections for total nitrogen, total phosphorus, lead and

zinc were estimated for average annual conditions.

A database of the land features within each sub-basin was required to

evaluate runoff flows and associated non-point pollution loadings.

Existing land use patterns in each sub-basin were derived from the 1986

Lake County Land Use Mapping Project (East Central Florida Regional

TABLE 5-3

SUMMARY OF LAKE COUNTY TROPHIC STATE INDEX ANALYSES

SECCHI MEAN CONCENTRATION DEPTH TOTAL-P TOTAL-N CHLOR-a TNKP TROPHlC STATE INDEX TSI

JAKE M l m a n l l m a n l lualL)RATlOCHL-ASECCHlTOTAL-PTOTAL-NAVGTSiRANKlNG BEAUClAlR 0.32 0.21 3.9 121.2 18.2 85.9 94.6 81.4 82.9 87.6 POOR CHERRY 2.00 0.01 2 0.6 3.84 50.3 36.2 39.3 28.2 46.4 34.5 GOOD DORA 0.31 0.14 3.8 106.7 27.6 84.0 95.2 73.0 82.2 85.6 POOR EUSTIS 0.56 0.05 2.4 45.0 43.9 71.6 77.6 55.7 73.0 68.3 FAIR GRIFFIN 0.46 0.08 3.2 69.5 37.3 77.9 83.4 64.2 78.8 75.2 POOR HARRIS 0.65 0.04 1.8 39.8 48.8 69.8 73.0 48.4 67.3 63.7 FAIR L. HARRIS 0.70 0.04 1.7 34.3 45.4 67.7 70.7 49.1 66.6 62.5 FAIR LOUISA 0.90 0.03 1 .O 6.9 33.5 44.5 63.2 44.0 55.2 50.5 GOOD MINNEHAHA 1.64 0.02 0.7 3.7 40.9 35.5 45.2 35.0 49.5 38.5 GOOD MlNNEOlA 2.22 0.04 0.6 4.8 16.3 39.5 36.1 49.9 47.1 41.4 GOOD YALE 1.8 0.02 1 .O 12.4 59.9 53.1 41.6 33.9 56.0 42.9 GOOD

Planning Council). Based on similarity of runoff characteristics, the

land use categories for each sub-basin were identified in Table 3-7.

Present land use for each of the selected lakes within Lake County is

presented in Table 5-4. The total percentage of each sub-basin in urban

land uses (e.g., residential+comrnercial+industrial) and agricultural land

uses (e.g., pasture+cropland) is also presented in Table 5-4.

Urban non-point pollution loadings tend to be governed by the amount of

imperviousness associated with each land use category. The amount of

imperviousness typically associated by specific urban land use categories tends to be similar throughout a particular region. The impervious cover

percentage for each land use category was estimated from literature factors

and other recent CDM studies in the region.

WNFALL/RUNOFF RELATIONSHIPS

Non-point pollution loading factors (lbs/acre/year) for different land use

categories are based upon annual runoff volumes and event mean concentra-

tions (EMCs) for different pollutants. The EMC is defined as the average

of individual measurements of storm loading divided by the storm runoff

volume. One of the keys to effective transfer of literature values for

non-point pollution loading factors to a particular study area is to make

adjustments for actual runoff volumes in the watershed under study. In

order to calculate annual runoff volumes for each basin, the pervious and

impervious fraction of each land use category was used as the basis for

determining rainfall/runoff relationships. For rural-agricultural (non-

urban) land uses, the pervious fraction represents the major source of

runoff or streamflow, while impervious areas are the predominant

contributor for most urban land uses.

Annual runoff volumes for the pervious/impervious areas in each land use

category were calculated by multiplying the average annual rainfall volume

by a runoff coefficient. The average annual rainfall for the eight

recording locations is approximately 51.1 inches (see Table 3-2). A runoff coefficient of 0.95 was used for impervious areas (i.e., 95 percent of

TABLE 5-4 SUMMARY OF LAKE COUNTY LAND USE AND HYDROLOGIC SOILS GROUP

LAKE laflsuk BUWCLAlBCARLTONCHERBY PQBB EUSTlS QRlRlN HARRlS LOUlSA L.HARRISMlNNEHAHAMlNNEOU YBLE Forestlopen 5.7% 7.8% 7.7% 6.7% 9.3% 12.0% 7.2% 4.6% 7.6% 7.7% 7.3% 15.1% Pasture 6.3% 5.8% 7.8% 6.0% 5.2% 6.1% 5.7% 7.4% 5.4% 8.4% 8.4% 3.1% Agricultural 16.5% 25.9% 31.3% 20.9% 22.7% 28.7% 33.2% 48.1% 45.6% 37.0% 37.0% 35.7% Low Density Resid. 3.7% 3.4"/0 2.3% 3.6% 4.2% 4.3% 2.6% 0.9% 2.0% 2.4% 2.3% 4.8% Med. Density Resid. 12.9% 9.5% 2.9% 11.3% 8.8% 5.4% 4.6% 0.5% 2.7% 2.8% 2.6% 3.1% High Den Resid. 0.0% 0.0% 0.1% 0.0% 0.0% 0.0% 0.0% 0.1% 0.0% 0.1% 0.0% 0.0% CommJLiiht lndust 5.8% 4.4% 2.8% 5.1% 4.0% 2.9% 2.7% 1.1% 1.5% 3.2% 3.0% 1.6% Heavy Industrial 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% Wetlands 6.5% 7.6% 22.5% 7.0% 9.5% 14.5% 20.3% 25.2% 16.6% 18.6% 20.3% 13.0%

4 2 . 6 % 3 5 . 5 % 2 2 . 7 % 3 9 . 3 % 3 6 . 3 % 2 6 . 1 % 2 3 . 7 % 1 2 . 1 % 1 8 . 6 % 1 9 . 7 % 1 9 . 0 % 2 3 . 6 % Total 100% 100% 100% 1 OOOh 100% 100% 10O0/~ 100% 100% 100% 100% 100°/~ Drainage Area (acres) 2,159 1,376 3,361 19,861 34,304 44,504 77,317 46,488 39,364 5,410 17,159 22,797 Hydrologic Soils Group

A 52.3% 77.5% 57.2% 53.9% 49.9% 37.2% 49.6% 53.2% 79.6% 56.0% 57.0% 42.5% B 0.09'0 0.0% 0.0% 4.5% 0.4% 0.0% 0.3% 0.0% 0.4% 0.0% 0.0% 0.0% C 0.0% 0.0% 0.0% 0.0% 4.0% 8.7% 11.5% 12.6% 2.0% 0.0% 18.6% 7.6% Q47.7%22.5%42.8%41.6%45.7%54.1%38.7%34.2%18.0%44.0%24.4%49.9%

Total 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%

% Agriculture 22.7% 31.8% 39.1% 27.0% 27.9% 34.8% 38.9% 55.5% 51.0% 45.4% 45.4% 38.8% % Urban 22.4% 17.3% 8.0% 20.0% 17.0% 12.6% 9.9% 2.6% 6.2% 8.6% 8.0% 9.5% % Watermetlands 49.1% 43.2% 45.2% 46.3% 45.8% 40.6% 44.0% 37.3% 35.2% 38.3% 39.3% 36.6%

the rainfall is converted to runoff from the impervious fraction of each

land use). Therefore, the average annual runoff from impervious areas is

about 48.5 inches/year. A pervious area runoff coefficient of 0.10 was

used. The total average annual surface runoff is calculated by weighting

the impervious and pervious area runoff factors for each land use category.

Water surfaces were assumed to be 100 percent impervious. Evaporation

losses were subtracted from precipitation falling directly on water

surfaces. An annual evaporation rate of 50.4 in/yr was used.

Average annual baseflow (i.e., dry weather flow) for rural-agricultural

areas and pervious areas in urban land uses was calculated by subtracting

average annual surface runoff from average annual streamflow measured at

the Little Creek USGS gage (02236700) which is located in Lake County.

For existing conditions, the average annual surface runoff volume from

both pervious and impervious surfaces is about 4 to 6 inches/year (based upon the runoff factors presented above). Based upon the difference

between total average annual flow and the average surface runoff, average

annual baseflow volume under existing land use conditions is approximately

8 to 9 inches/year. This method of obtaining base flow is sufficient for a

preliminary loading analysis. However, for the more detailed Master plan

investigations, base flow values will be more completely identified.

In other words, baseflow accounts for the majority of the average annual

total flow volume. Surface runoff or stormwater flows, which occur for

relatively short periods at random intervals, account for less than half of

the total flow volume but the majority of the annual non-point pollution

loadings.

ANNUAL NON-POINT POLLUTION LOADING FACTORS

Non-point pollution monitoring studies throughout the U.S. over the past

10 years have shown that annual "per acre" discharges of urban stormwater

pollution (e.g., nutrients, metals, BOD, fecal coliforms) are positively

related to the amount of imperviousness in the land use (i.e., the more

imperviousness the greater the non-point pollution load).

Since stomter management recommendations are needed as soon as

practicable, it was not feasible to undertake a stormwater non-point

pollution monitoring study for use in the Lake County needs assessment. In

place of an expensive local stormwater monitoring program, available

literature values for non-point pollution loading factors were used for the

preliminary non-point pollution loading evaluation. This approach has

worked quite well in some previous stomter management studies where

mixed land use monitoring data was available for comparison. For example,

Table 5-5 compares urban non-point pollution loading factors for total

phosphorus which were derived from local monitoring studies (total

monitoring costs in excess of $1.5 million) in the Occoquan Reservoir

watershed of northern Virginia with loading factors based upon the median

event mean concentrations (EMC) from the pooled national database for the

U.S. EPA Nationwide Urban Runoff Program. As may be seen, the loading

factors based upon the national database are in relatively good agreement

with the local loading factors. More important, water quality management

decisions based upon the loading factors would not be

significantly different from those based upon the "local" loading factors.

Preliminary pollutant loading analyses are limited to the constituents for

which considerable loading data are reported in the literature. The

non-point pollution loading evaluation was limited to the following four

pollutants: total Phosphorus (total-P), total Nitrogen (total-N), lead,

and zinc. Total-P and total-N are required in order to perform evaluations

of eutrophication impacts. Lead and zinc are heavy metals which typically

exhibit higher non-point pollutant loadings than other metals found in

urban runoff. These heavy metals may be viewed as surrogates for a wide

range of toxicants that have been identified in previous field monitoring

studies of urban runoff pollution (USEPA, 1983). For this preliminary

evaluation, loading factors applied to the Lake County study area for this

evaluation are presented in Table 5-6. Preliminary non-point pollution

loading factors are presented for SCS hydrologic soils group A, B, C,

and D. These factors will be adapted to the specific soils in the study

area. The development of these loading factors is described below.

TABLE 5-5

COMPARISON OF AVERAGE ANNUAL TOTAL-P LOADING FACTORS FOR URBAN LAND USES: OCCOQUAN WATERSHED MONITORING STUDY VS. NURP NATIONAL STATISTICS

Annual Annual Total-P Loadina a Runoff (lbs/acre/yr)

Land Use (inches/yr) Occoquan MJRP

Residential 14.4 1.1 1.2

Mixed 22.9 1.3 (50% residential and 50% commercial)

Commercial 31.4 1.5 1.4

Notes :

1. Annual runoff is based upon average annual rainfall of 40.6 inches.

2. "Occoquan" loading factors are based upon northern Virginia monitoring studies of single land use watersheds (Hartigan et al., 1983; NVPDC, 1979) ,

3. "NURP" loading factors are based on the following median event mean concentrations (EMCrs) for pooled nationwide NURP database: 0.383 mg/L for residential; 0.2 mg/L for commercial; and 0.263 mg/L for mixed (USEPA, 1983b).

A number of studies are available which discuss non-point pollution loading

factors. The Orlando Metro Areawide Water Quality Master Plan (ECFRPC,

1978) listed a series of values which are shown in Table 5-7. Based on the

Tampa National Urban Runoff Program (NURP) results, two reports prepared by

CDM define EMC values: Tributary Streamflows and Pollutant Loadings

Delivered to Tampa Bay (for FDER, 1984) and Southeast Area Stormwater

Management Study: Final Report (for Manatee County, 1985). Tables 5-8 and

5-9 present the EMC values from these two documents. Since the 1978

Orlando 208 study, sampling methods and analysis techniques have been

refined by NURP approaches and data. Therefore, the Tampa NURP EMCs were

used for this study because they represent the most up-to-date local data

for actual storm-related pollutant loads.

Also shown in Tables 5-8 and 5-9 are the assigned impervious percentages

for each of the land uses. The percentages represent the percent of a

particular land use area which is impervious. It should be noted that the

values do not necessarily represent directly connected impervious area

(KIA). Using a single family residence as an example, rain falls on

rooftops, sidewalks, and driveways. The sum of these areas may represent

30 percent of the total lot. However, much of the rain that falls on the

roof drains to the grass and does not directly run to the street, some infiltrates to the ground, and some runs off the property. Thus, not all

of the 30 percent impervious area actually contributes as impervious area

and the DCIA percentage is less than the total impervious percentage.

Experience shows that the DCIA percentage is on the order of 50 to 90

percent of total impervious percentage.

Another primary source of loading factor data is the "Guidebook for

Screening Urban Non-Point Pollution Management Practicest' developed for

northern Virginia (NVPDC, 1979). To derive these loading factors,

non-point pollution loading parameters were calibrated to single land use

monitoring data using the EPA NPS model, a continuous simulation non-point

pollution loading model (Hartigan, et al., 1978, 1983). The EPA NPS model

was then applied with an hourly precipitation record for a year of average

rainfall to generate annual loading projections for individual land uses,

TABLE 5-6

SUMMARY OF NONPOINT POLLUTION LOADING FACTORS BY HYDROLOGIC SOILS GROUP

Typical Lot

Land Use Size % Imperv

Forest 0.5% Pasture 0.5% Cropland 0.5% Low Den Resid 1.0-ac 15.0% MDSF Resid .25-ac 35.0% High Den. Resid 80.0% Co-ight Indust 90.0% 0.2 Heavy Indust 90.0% Wetlands 100.0% Water 100.0%

Typical Lot

Land Use Size % Imperv

Forest 0.5% Pasture 0.5% Cropland 0.5% Low Den Resid 1.0-ac 15.0% MDSF Resid .25-ac 35.0% High Den.Resid 80.0% Cormn/Ligh Indust 90.0% Heavy Indust 90.0% Wetlands 100.0% Water 100.0%

Lead (rngh) A B C

Zinc (mgh) B C D - - -

TABLE 5-7

EVENT MEAN CONCENTRATIONS FOR THE ORLANDo METRO AREAWIDE WATER QUALITY STUDY

(ECFRPC, 1978)

Land Use

Single Family Residential

Commercial

Improved Pasture

Well-drained

Flatwoods

Rangeland

Lake

TABLE 5-8

EVENT MEAN CONCENTRATIONS AND IMPERVIOUS PERCENTAGES FOR THE TAMPA BAY STUDY

(CDM, 1984)

Impervious Land Use TN (mg/l) TP (mg/l) Percent

Single Family Residential 1.87 0.39 30%

Multi-Family Residential 1.65 0.33 50%

Commercial 1.18 0.15 90%

~ndustrial 1.18 0.15 70%

Institutional 1.77 0.20 5%

Recreation and Open 1.21 0.21 5%

Undeveloped 1.15 0.15 1 %

Rainfall 0.91 0.17 N/A

Agricultural with BMPs 1.03 0.21 1 %

TABLE 5-9

EVENT MEAN CONCENTRATIONS AND IMPERVIOUS PERCENTAGES FOR THE MANATEE COUNTY SOUTHEAST AREA STUDY

( C D M , 1985)

Impervious Land Use TN (mg/l) (mg/l) Percent

Forest 1.02 0.16 1%

Golf Course 1.21 0.21 1%

Cropland 3.74 1.13 1 %

Wetland 1.02 0.16 1 %

Orchard 0.92 0.41 1 %

Low-Densi ty Single Family 1.87 0.39 20% Residential

Medium-Density Single Family 1.87 0.39 30% Residential

Townhouse/Garden Apartment 1.65 0.33 50% Residential

Off ice 1.18 0.15 90%

Commercial 1.18 0.15 90%

Extractive 1.18 0.15 45%

Industrial 1.18 0.15 70%

Highway 1.18 0.15 90%

Waterbody 0.79 0.17 100%

which were further refined to include loading factors for different ranges

of imperviousness and soil textures. With the exception of the 5-acre lot

single family residential category, the NPS model projections for

residential land uses assumed that all pervious area was covered with

fertilized lawn surfaces. For the 5-acre lot category, it was assumed that

about 2 acres was covered with fertilized lawns and about 3 acres was

maintained with tree cover.

To account for differences in soils characteristics, loading factors were

varied by hydrologic soil group. The "Guidebook" loading factors rely on

soils texture classifications. For this study, hydrologic soil groups were

assigned the following soil texture classifications:

SCS Hydrologic Soil Soil Texture

Group Classification

Fine Sand, Sandy Loam Find Sand Loam Find Sand, Silt Loam Find Sand, Clay Loam

In order to effectively transfer literature values for loading factors to

the Lake County study area, adjustments for actual hydrologic conditions in

the watersheds under study had to be made. This was done by converting

literature values to event mean concentrations (EMC) and multiplying by the

surface runoff volumes for each land use category as described previously.

BASEFLOW LQADING FACMRS

Baseflow from all land use categories was assumed to exhibit the same

concentrations of nutrients and heavy metals. Based upon a review of

monitoring statistics for of the following Lake County Environmental

Services monitoring stations in the study area:

River Station Numbers

Palatlakaha River 324, 330, 331, 44

Big Creek 323

Little Creek 322

the following mean concentrations were assumed for baseflow:

o Lead: 0.0 mg/L

o Zinc: 0.0 mg/L

These concentrations are assumed to be representative of baseflow water

quality which is not impacted by point source discharges. Water quality data from the Haines Creek Muck Farm study areas reviewed however and

total-P concentrations are a factor of ten higher and near total-N

concentration area a factor of 2-3 higher.

For each subbasin and land use scenario, total annual baseflow volume was

multiplied by these loading factors to derive annual baseflow loadings

discharged into the selected lakes.

5.4.4 FAILING SEPTIC TANK IMPACTS

About 60 percent of the population within Lake County rely on household

septic tanks and soil absorption fields for wastewater treatment and

disposal. In June 1979, the Septic Tank Nonpoint Source Element of the

State Water Quality Management Plan identified Lake County as one of the

ten highest-ranking counties in the non-designated area of Florida for

potential septic tank failure (based on soil absorption system density and

soil limitations). The non-point pollution loading factors for low density

residential areas, which are typically served by septic tank systems are

based on test watershed conditions where the septic systems were in good

working order and the septic tanks systems made no significant contribution

to the monitored non-point pollution loads. In fact, septic tank systems

typically have a limited useful life expectancy and failures are known to

occur which cause localized water quality impacts. This section presents

estimates of average annual septic tank failure rates based on a literature

review, and the methodology used to calculate additional non-point

pollution loadings discharged to the lakes from failing septic systems.

To estimate an average annual failure rate, the time series approach

proposed by the 1986 EPA report Forecasting Onsite Soil Adsorption System

Failure Rates was used. This approach considers an annual failure rate

(percent per year of operation), future population growth estimates, and

system replacement rate to forecast future overall failure rates.

AII annual septic tank failure rate of between 2 and 3 percent per year was

assumed for Lake County. This is somewhat conservative as literature

values reported for areas across the U.S. range from about 1 to 2 percent.

For average annual conditions, it was assumed that septic tank systems

failures would be unnoticed or ignored for five years before repair or

replacement occurred. Therefore, during an average year, 10 to 15 percent

of the septic tanks systems in the watershed were assumed to be failing.

pollutant loading rates for failing septic systems were developed from a

review of septic tank leachate monitoring studies. The mean concentrations

of total-P and total-N assumed based upon literature values are as follows:

Low 1.0 mg/L

Medium 2.0 mg/L

High 4.0 mg/L

Annual "per acre" loading rates for septic tank failures from low density

residential land uses were then estimated assuming 50 gpcd wastewater

flows. The loading rates were applied to the percentage of all non-sewered

residential land uses with failing septic tanks. The septic tank loading

factors were added to the runoff pollution loading factors. The percent

increase in annual per acre loadings attributed to failing septic tanks is:

Total-P Total-N

LOW 130%-180% 120%-150%

Medium 160%-250% 140%-200%

High 220%-400% 180%-310%

Despite the large increase in annual loading rates, septic tank failures

have only a limited impact on overall non-point pollution discharges. This

is because the increased annual loading rates were applied only to the

fraction of non-sewered residential development that are predicted to have

a failing septic tank system during an average year.

It should be noted that this analysis is preliminary in nature. Detailed

analysis of septic tanks and their effects on water quality, similar to the

July 1982 Septic Tank Water Quality Impact Study, would better guide Lake

County in the efficient use of septic tanks and their effects on water

quality in Lake County.

5.4.5 AVERAGE ANNUAL NON-POINT POLLUTION LOADS

Average annual non-point pollution loadings discharged into the each of the

study area lakes were calculated using the loading factors described

earlier. Bar charts of the projected average annual non-point pollution

loadings in pounds per year of total-P, total-N, lead, and zinc are

presented in Figures 5-10 through 5-13. Each individual bar represents the

estimated total loadings to each of the study area lakes. Since non-point

pollution loading factors for nutrients (total-P and total-N) and metals

(lead and zinc) are related to specific land uses and imperviousness, the

comparison of projected non-point pollution loadings across the study area

lakes follow similar patterns for the nutrients and metals.

Ranking the study area lakes by nutrient loading tends to follow the

relative size of the total area draining to each lake. The lakes with the

AVERAGE ANNUAL LOAD: TOTAL-P

CARLTON DORA GRIFFIN LOUISA MINNEHAHA YALE LAKE

AVERAGE ANNUAL LOAD: TOTAL-N 250,000

CARLTON CHERRY '

DORA EUSllS

' HARRIS 'MINNK)~

GRIFFIN LOUISA MINNEHAHA YALE LAKE

AVERAGE ANNUAL LOAD: LEAD

AVERAGE ANNUAL LOAD: ZINC

BEAUCIAlR CHERRY HARRIS ' .L HARRIS' 'MINNEO~ CARLTON DORA GRIFFIN LOUISA MlNNEHAHA YALE

LAKE

largest drainage areas (e.g., Lake Harris, Lake Louisa, Little Lake Harris,

and Lake Griffin) are projected to receive the highest annual loadings of

nutrients. BY comparison, ranking the lakes by projected annual loading of metals follows a different pattern which appears to be related to the

amount of existing urban development within the drainage area.

"Per Acre" Loads

Bar charts summarizing the "per acre" loads to each of the study area lakes

are presented in Figures 5-14 to 5-17. The mass loadings presented above

provide an estimate on the total load discharged to the major reach

segments. By normalizing the loads on a "per acre" basis, subbasins with

land uses that generate disproportionately high loading rates can be

identified. Figures 5-14 and 5-15 indicate that although the total mass

loads of total-P and total-N discharged to the study area lakes varies

significantly, the projected "per acre" contribution of nutrients is

relatively fairly constant and does not appear to be a good indicator

potential water quality problems. For total-P, the loading rate is about

0.6 to 0.8 lbs/ac/yr. Similarly, the upstream "per acre" contribution of

total-N is about 2.5 to 3.0 lbs/ac/yr.

For heavy metals, the relative differences between "per acre" contributions

are more pronounced. Figure 5-16 and Figure 5-17 suggest that "per acre"

heavy metals loadings from Lake Beauclair, Lake Dora, Lake Carlton and Lake

Eustis are relatively higher that the remaining lakes. "Per acre" loading

of lead are projected to be greater than 0.10 lbs/ac/yr, while the

remaining lakes are projected to have lead loadings well below 0.08

lbs/ac/yr. This likely to be a result of the relatively larger areas of

urban land uses draining to these lakes. These results are consistent with

monitoring data collected during 1985 to 1990 by the Lake County

Environmental Services Department.

Structural Best Manasement Practices

Non-point pollution loadings were calculated only for existing land use

conditions. For the Stomater Master Plan, the non-point pollution

AVG. ANNUAL "PER ACRE" LOAD: TOTAL-P

BEAUCUIR ' CHERRY I EUSTIS I I HARRIS ' L HARRIS' ' M I N N E ~ '

CARLTON DORA GRIFFIN LOUISA MINNEHAHA LAKE

YALE

AVG. ANNUAL "PER ACRE" LOAD: TOTAL-N

BEAUCLAI A ' CHERRY I HARRIS CARLTON DORA GRIFFIN LOUISA

I L HARRIS' MINNEOLA' I

MINNEHAHA YALE LAKE

AVG. ANNUAL "PER ACRE" LOAD: LEAD

AVG. ANNUAL "PER ACRE" LOAD: ZINC

- - - - - - - - - m e - - - -

CARLTON DORA GRIFFIN LOUISA MINNEHAHA YALE LAKE

loading model can be used to provide a preliminary indication of the

potential benefits that could be achieved by a structural best management

program. An example of this analysis, might be to calculate non-point

loads assuming that 100% of future urban development would be served by

BMPrs with pollutant removal efficiencies equivalent to wet detention

basins. Areas of existing urban development already served by structural

BMP'S could also be included in this analysis.

Non-Point Pollution Loadinu Taruets

Future non-point pollution loadings targets may be tied to water quality

goals in the Stomter Master Plan. Potential water quality goals might

include: improvement, non-degradation or minimal degradation of water

quality under future conditions. While mass loads of pollutants alone

cannot answer whether water quality goals will be met, comparison of

projected loads under existing and future conditions provides some

indication as to whether future trends will be toward improving versus

deteriorating conditions. An example of using the non-point pollution

loading model to evaluate a water quality goal would involve calculating

the ratio of future to existing loads for the of the study area lakes. A

ratio of future to existing loads of 1.0 would indicate that future loads

are projected to be equivalent to existing loads. A ratio of less than 1.0

would indicate declining loads in the future and greater than 1.0

increasing loads. A non-degradation water.quality goal might correspond to

ratio of future to existing loads of 1.0 which might be a reasonable

loading target for those lakes exhibiting good water quality under existing

conditions. For those lakes exhibiting poor water quality, a ratio of less

than 1.0 might be the water quality goal. Implementation of BMPts could

have a profound impact in reducing future loads to the lakes.

5.5 SUMMARY

This preliminary loading analysis only provides a portion of the

information required to analyze water quality problems on Lake County.

Based upon this analysis and ambient water quality data, it appears that

several major lakes in the County are experiencing declines in water

quality (e.g., ~ake Beauclair, Lake Dora, and Lake Griffin). In addition, a separate SWIM plan for Lake Apopka is in the process of implementation to

correct the long-term water quality decline in that lake. In order to

properly evaluate future nonpoint source pollutant load impacts on major

lakes in the County, a lake receiving water quality model is needed to

predict the location and magnitude of water quality impacts resulting from

pollutant loadings to each of the lakes. This water quality model should

be included in future phases of the County's Stormwater Management Program.

6.0 PROBLEM AREAS

6.1 GENERAL

An essential task in stormwater management planning is the identification

of problem areas in order to establish priorities for need in the Capital

Improvements Program (CIP). As part of this, the definitions presented

below were used to categorize Lake County problem areas.

6.1.1 WATER QUANTITY (FLOODING)

Serious Problem Area:

o An imminent threat to public safety and/or property including

loss of human life, blockage of evacuation and/or emergency

vehicle routes, and/or flooding of homes/buildings. This will be

evaluated by the following criteria:

- hzacuation/emergency roads being overtopped by flood stages

from storm events equal-to or more frequent-than the 100-year,

24-hour event.

- Velocities for these events greater than five feet per second

for structures and three feet per second for earthen channels.

- Greater-than one foot of head loss across a structure for

these events. This can be an indication of potentially

erosive velocities.

Nuisance Problem Area:

o Minor street flooding which causes inconvenience, traffic delays,

and possibly the temporary blockage of secondary roads

non-essential for evacuation and/or emergency vehicle use.

Serious Problem Areas:

o Violation of Chapter 17-3, FAC criteria unless a

naturally-occurring condition of non-compliance can be documented.

o Impairment of a unique environmental use:

e.g., fishing, swimming, springs, threatened and/or endangered

species habitat, other.

o The presence of toxic, hazardous, and/or man-made inorganic/

organic substances in sediments.

Nuisance Problem Areas:

o Some minor changes in color, turbidity, and/or odor that may be naturally occurring or just within limits of Chapter 17-3, FAC

criteria.

o Qualitative assessment of water quality.

It should be noted that prior to the late 1970s (i.e., the date when the

State enacted most stonwater regulations) stonwater management systems

were constructed to convey stomater runoff from one area to another

without providing for the treatment of stormwater runoff. Thus, many

stormwater systems installed prior to 1978 would need to be retrofitted

should the County desire to provide the same level of service as required

by current standards for the treatment of stormwater. A discussion of this

retrofit problem is presented in the next section.

6.2 PROBLEM AREA IDENTIFICATION AND EVALUATIONS

For this report's level of detail, facilities with capacity deficiencies,

or problem areas, were identified by interviews with Lake County personnel,

and personnel for cities and towns in the County, adjacent counties, and

state and federal agencies. The following list of interviews was performed

to identify problem areas. Problem areas for other cities, adjacent counties, and agencies were identified by letters and telephone

conversations.

INTERVIEW LIST

Lake County

Don Findell, Director of Environmental Services Jim Stivender, Director of Public Works Don Griffey, Engineering Director Larry Kirch, Chief Planner Sam Sebaali

Lake County Water Authority

Will Davis

City of Fruitland Park

Bob Allen, Public Works Superintendent

City of Groveland

Rodney Schultz, Director of Public Works

City of Mascotte

Henry Sharpe, Director of Public Works

City of Minneola

Gary Thornson, Director of Public Works

Citv of Umatilla

David Hanna, Director of Public Works

Town of Astatula

Olive Ingram, Town Clerk

Town of Howey-in-the-Hills

Gay Brumley, Town Clerk

Town of Ladv Lake

Chip Ross, Public Works Director Ted Wicks, Town Engineer

Town of Montverde

Helen Pearce, Town Clerk

Based upon the interviews and review of the available data presented in

Section 2.0, the problem areas presented below were identified. Field

visits were conducted to assess the reported problem areas and photographs

were taken for reference. In some cases, reported problem areas had

already been addressed. Preliminary improvement recommendations for the

unsolved problem areas were then made and conceptual probable cost

estimates were determined. It should be noted that prior to implementing the suggested improvements presented below, a detailed stormwater design

analysis should be performed to verify the assumptions used in this

conceptual planning study.

Table 6-1 presents the location of the problem areas with their respective

basins and subbasins. Figure 6-1 shows the approximate location of the

water quantity problem areas.

Lake County

LC1 - Astor Area Problem Summary

Located in the northeastern portion of the County, the Astor problem

area experienced flooding problems in the early eighties. This area

falls entirely within the St. Johns River Basin and for the most part

lies within flood prone areas as identified in Federal Emergency

Management Agency (FEMA) Flood Insurance Rate Maps. Lying immediately adjacent to the River, the occurrence of a major storm event (i.e.,

25-year, 24-hour) would result in widespread flooding directly

L C 1 . 7 - 1 TABLE 6 - 1 220-GG-LAKE 0 5 / 0 1 / 9 1 WATER QUANTITY PROBLEM AREAS

BY SUB-BASIN

B A S I N

O k l a w a h a R i v e r

W e k i v a R i v e r

S t . J o h n s R i v e r

W i t h 1 a c o o c h e e R i v e r

K i s s i m m e e R i v e r

SUB-BASIN

L a k e W e i r

L a k e Y a l e

L a k e G r i f f i n

L a k e E u s t i s

G o l d e n T r i a n g l e

L a k e A p o p k a

L a k e H a r r i s

P a l a t 1 a k a h a

B l a c k w a t e r C r e e k


A l e x a n d e r S p r i n g s

L a d y L a k e

L o g g y Pond Swamp

SE F r u i t l a n d P a r k

G r o v e l a n d - M a s c o t t e

L a k e O k a h u m p k a

Reed Hammock Pond

T r o u t L a k e

I D #

- - - LC2

- - - UM1 UM2

LC3

- - - - - - M I 1 M I 2

- - - - - - L C 1

L L 1

- -- - - - G R 1 GR2 GR3 GR4 GR5 G R6 GR7 MA 1 MA2

- - - - - - - --

DESCRIPTION

- - - - - L a k e Y a l e D i k e

- - - - - S e m i n o l e S t r e e t L a k e s i d e A v e n u e

W o l f B r a n c h Road

- - - - - - - - - -

C h e s t e r S t r e e t W a s h i n g t o n S t r e e t

- - - - - - - - - -

A s t o r A r e a

Oak G r o v e S u b d i v i s i o n

- - - - - - - - - -

G r o v e l a n d H i g h S c h o o l G a d s o n A v e n u e B a l d w i n A v e n u e Sampey Road M o u n t P l e a s a n t Road P a r k S t r e e t M a s c o t t e P a r k L a u r e l S t r e e t Oaks S t r e e t

- - - - - - - - - - - - - - -

0-

miles

L

LEGEND

PROBLEM AREA (e.g. , LC2) OR PROBLEM AREA CLUSTER (e.g., GR1-7)

NOTE: FOR A LIST OF THE PROBLEM AREAS, REFER TO THE WATER QUANTITY PROBLEM AREA SECTION.

WATER QUANTITY PROBLEM AREAS en wronmen to1 eng~neers, sclen tists.

planners. & monogemen t consultan ts CDM FIGURE 6-1

affected by the flood stages of the river itself. Protection from

flooding may be possible by building a dike around the flood prone

area, and provide pumps to convey stonwater runoff from the diked

area to the river. In order to have such a system permitted the

following items need to be sufficiently addressed for regulatory

agency approval: (1) treatment of the stormwater for the diked

system; (2) no adverse flood plain or floodway conveyance impacts; and

(3) providing for compensating storage. In reviewing the flood prone

area, approximately two square miles would need to be diked, and the

length of diked area would be east to west which would be

perpendicular to the flow (south to the north) of the St. Johns River.

Due to the large compensating storage volume and the apparent

constriction of the St. Johns River floodway, it appears that a diked

system for this area would be difficult to receive permit approval.

Therefore, structural improvements may be difficult to implement in

this area. Even if these improvements are permittable, non-structural

controls such as floodplain development restrictions would need to be

enforced. To determine whether the diked system is feasible, a future

basin study of sufficient detail to address the regulatory

requirements is recommended to be performed.

Recommended Capital Improvements. Conduct a detailed stornrwater

study for this area.

Conceptual Probable Cost Estimate. Project costs for the

stormwater study are estimated to be approximately $200,000.

LC2 - Lake Yale Dike Problem Summary

Recently a dike failed in a canal connecting Lake Yale to Lake

Griffin. The dike consisted of a clay road with a 24" diameter

corrugated metal pipe (CMP). Following the "wash-out", the clay road

was reconstructed and a 36"'diameter CMP was installed. Riprap

consisting of broken concrete blocks was placed at the entrance and

exit of the culvert. Located approximately 50' east of a 10 feet wide

by 12 feet high box culvert passing under County Road 452, the

capacity of the CMP relative to the box culvert is small. The CMP is

a constriction to the canal which when subjected to peak flows

produced by major storm events results in overtopping of the

dike/road. Further wash-outs could occur, although public safety does

not appear in jeopardy since County Road 452 (downstream) appears to

be a solid structure.

Recommended Capital Improvements. Improve erosion control to

protect the existing structure and allow this non-essential road

to be safely overtopped for large storms.

Conceptual Probable Cost Estimate. Project costs are estimated to

be $16,000.

LC3 - Wolf Branch Road Problem Summary

In the past, major storm events have produced flooding which resulted

in the overtopping of Wolf Branch Road. Two 8Ix8' CBCs were installed

to pass peak flood flows under the road. A 4-1/2' high sharp crested

weir with two manually controlled slide gates was installed at the

culverts entrance to maintain the water surface elevation of an

existing small pond immediately upstream. This was done to

accommodate the request of an adjacent land owner. The presence of

the weir effectively reduces the capacity of the culverts even with

the slide gates fully opened. This creates the potential for

overtopping of the road which would block a potential evacuation route

by high flood stages or structural damage to the road itself. Higher

flood stages are also predicted upstream.

Recommended Capital Improvements. Widen the existing weir length to 30 feet while maintaining the desired elevation of 4-1/2' above

the invert of the CBC entrance. This longer weir will increase

weir capacity and mitigate some of the interactions between the

culvert and weir. Erosion protection should be provided upstream

and downstream of the road in the form of armorform lining or

equivalent to protect the road from failure.

Conceptual Probable Cost Estimate. Capital costs are estimated to

be $31,000.

Citv of Fruitland Park

No problem areas requiring capital improvements have been identified at

this time.

Citv of Groveland

The City of Groveland reported the most problem areas of all cities and

towns located in Lake County. There are seven problem areas located in the

City of Groveland. Because of the interaction of the stormwater system

with the problem areas in the City, a detailed stormwater basin plan to

assess hydrological and hydraulic conditions throughout the system is

warranted. This basin plan would determine the most cost effective and

environmentally sound approach to alleviate the problem areas located in

the City of Groveland. Presented below is a summary of the City of

Groveland problem areas, and preliminary recommendations, which need to be

verified with the recommended basin plan, for alleviating the stormwater

problems.

GRl - Groveland High School Problem Summary

Ponding of runoff frequently occurs in a depressional area which is

part of the schoolyard located northwest of intersection of Parkwood

Street and State Road 33 (SR 33). No reports of runoff entering

surrounding buildings has been recorded. As the depressional area stages up, it discharges into a 36" diameter reinforced concrete pipe

(RCP) running southeasterly into a roadside ditch along SR 33. This ditch outfalls into a canal system beginning on the east side of SR 33

through a 2 feet high by 4 feet wide box culvert. No reports of road

overtopping have been recorded. The use of the physical education

facilities located in the problem area is limited until the runoff

infiltrates into the underlying soil.

Recommended Capital Improvements. Regrade the schoolyard with

provisions for a swale outfalling into a retention/detention pond

with a control structure to detain and treat runoff from the

ponding area prior to discharging to the existing 36" diameter

RCP .


GR2 - Gadson Avenue Problem Summary

A 36" diameter RCP passing under Gadson Avenue north of its

intersection with Parkwood Street is experiencing erosion problems at

both the entrance and exit of the culvert. This is evident due to the lack of an established uniform vegetative cover on the embankments.

The two-lane road appeared structurally sound at the time of the site

visit, but the potential exists for additional deterioration of the

embankment to occur if the road is overtopped. This can produce structural damage to the road which could potentially endanger public

safety.

Recommended Capital Improvements. Installation of concrete

headwalls at both the entrance and exit of the culvert,

construction of erosion control at the downstream end, and the

placement of sod on the eroded embankment.


be $9,000.

GR3 - Baldwin Avenue Problem Summarv

Located on Baldwin Avenue south of SR 50, a 30" diameter corrugated

metal pipe (CMP) is experiencing erosion problems at the downstream

end of the culvert which does not have an established uniform

vegetative cover on the embankment. The upstream embankment has

adequate vegetation. The two-lane road appeared structurally sound at

the time of the site visit, but the potential exists for additional

deterioration of the embankment to occur if the road is overtopped.

This can produce structural damage to the road which could potentially

endanger public safety.

Recommended Capital Improvements. Preliminary analyses indicate

0.5 feet of overtopping of the road during the 25-year, 24-hour

storm event. In order to increase culvert size, treatment of

upstream area would be required for a permit. The cost of such

treatment would be prohibitive due to wetland constraints. This

makes the installation of larger or multiple culvert(s) unlikely.

Therefore, it is recommended that the existing 30" CMP be replaced

with a 30" diameter RCP with concrete headwalls, erosion

protection at both the entrance and exit, and approximately 2

ac-ft of off-line detention storage upstream to lower upstream

flood stages. To protect the integrity of the roadway for flood

conditions, the embankments should be re-graded to no steeper than

4H:lV and sodded.


GR4- Sampey Road Problem Summary

Located on the north side of SR 50, just downstream of the Baldwin

Avenue Problem Area, two 4 feet high by 8 feet wide concrete arch

culverts experience an increase in backwater elevations caused by

clogging with vegetation. The problem is reported to occur frequently

and is remedied by removal of the aquatic vegetation. This provides

an increase in the level of service of the facility by restoring the

capacity of the culverts and consequently, mitigates upstream flooding

through the reduction of backwater elevations.

Recommended Capital Improvements. Preliminary analyses indicate

that the two culverts passing under Sampey Road and the two

6-10

culverts passing under SR 50 in between Sampey Road and Baldwin

Avenue, have adequate capacity to convey the 25-year and 24-hour

storm event without overtopping of the roadways. Therefore, the

only capital improvements recommended are for erosion control.

Armorform is recommended to be placed at the entrances and exists

of the culverts passing under SR 50 and Sampey Road. Increased

maintenance, at least on a quarterly basis, is recommended during

the growing season.

Conceptual Probable Cost Estimate. The capital costs for erosion

control improvements are estimated to be $10,000.

GR5 - Mount Pleasant Road Problem Summary

Overtopping has been reported on Mount Pleasant Road at a depressional

area (Bonnet Strand) located west of Lake David. Two 36" diameter

culverts serve as an outfall for Bonnet Strand which receives

discharges from Lake David. This area lies within flood prone areas

as identified in Federal Emergency Management Agency (FEMA) Flood

Insurance Rate Maps. The top of road elevation is approximately 6"

above the top of the culverts. Embankments at both the upstream and

downstream ends of the culvert appeared to be stable. There were no

visible signs of structural deterioration of the road itself.

Recommended Capital Improvements. Since this area is located in a

FEMA flood prone area, a detailed hydrological and hydraulic

evaluation is required to determine capital improvements.

Therefore, no capital improvements can be assessed at this time.

A recommendation for improvements in this problem area should

result when a detailed basin plan is performed for this area.

Conceptual Probable Cost Estimate. To be determined in a future basin plan.

GR6 - Park Street Problem Summary

Flooding has been reported immediately downstream of six 12" and two

36" CMPs located on Park Street, an extension of Ardmore Road, west of

its intersection with Savage Street. The flooding has encroached on

the surrounding residential area with no reports of runoff entering

the homes recorded. The top of road elevation at this crossing is

approximately 3" above the top of the culverts. Overtopping of the

road at this location has been reported, which may result from

backwater effects produced by downstream conditions. Embankments at

both the upstream and downstream ends of the culverts appeared to be

stable. There were no visible signs of structural deterioration of

the road itself.

Recommended Capital Improvements. Replace the eight CMPs with an

equivalent capacity 3 feet high by 4 feet wide concrete box

culvert as well as regrade the channel approaches and sod the

embankments.


be $25,000.

GR7 - Mascotte Park Problem Summary

Recently a clay core road with two 48" diameter CMPs was placed across

the canal downstream of the area described in Problem GR6 above,

within an adjacent park to the west. Reports of overtopping of the

road have not been recorded. Even though the structural integrity was

intact at the time of the site visit, the lack of embankment

protection, such as a uniform vegetative cover, creates the potential

for severe damage resulting from overtopping of the road, although

this road is in a rural area. This occurrence would result in a

reduction in the facility level of service.

Recommended Capital Improvements. Regrade eroded slopes, install

a concrete headwall at the entrance and exit of the culverts, and

sod the embankments.


be $23,000.

City of Mascotte

MA1 - Laurel Street Problem Summary

Frequent flooding problems are occurring in a natural depression

southeast of the intersection of Laurel Street and Woodland Avenue.

Lacking a natural outfall, the depression floods the adjacent mobile

home park. In the past, flood stages within the depression have

approached critical levels (i.e. enter the surrounding mobile homes).

A pump was used to pump runoff into Lake Jackson to the east. Lacking stormwater management facilities, the potential exists for home

flooding.

Recommended Capital Improvements. Convert the depression into a 2

acre wet detention pond (2.5 acre land purchase), install a

control structure, and construct a 750 feet long ditch to the

northeast, outfalling into Big Prairie. Flood waters will be

controlled and discharges will receive water quality treatment.


be $227,000.

MX2 - Oaks Street Problem Summary

Lacking stormwater facilities, a residential development located

immediately southwest of Lake Jackson, is experiencing frequent

flooding and erosion problems. The primary problem area runs from the

intersection of Elizabeth and Oaks Street to the intersection of Oaks

and Carol Streets to the east. From this point runoff flows in

between homes outfalling into Lake Jackson. Erosion appears to be due to the lack of uniform vegetative cover along the streets and steep

grades. Reports of runoff entering homes has not been recorded.

Under current conditions, the occurrence of a major storm event could

produce home flooding and severe erosion.

Recommended Capital Improvements. Installation of a 24" RCP storm

sewer system to convey runoff into a wet detention pond with

controlled outflow into Lake Jackson. The contributing area of

8.3 acres will receive retrofit treatment.


be $288,000.

City of Mi~e0la

MI1 - Chester Street Problem Summary

Frequent flooding problems are occurring in a natural depression

southeast of the intersection of Main Avenue and Chester Street to the

east of Lake Mimeola. Lacking a natural outfall, the depression

floods the adjacent residential area. The potential exists for

extensive damages to the surrounding community resulting from a major

storm event. A storm sewer system with a retention/detention pond

outfalling into Lake Mimeola would mitigate flooding. Due to a

shortage of undeveloped land in this area on which to construct the

pond, the above alternative may be abandoned in favor of an

exfiltration trench system. The problem area is approximately 25 feet

above the Lake surface and consists of Type "A" soils, making the

trench a potential alternative.

Recommended Capital Improvements. Installation of a combined

storm-sewer/exfiltration system to treat and convey flow to Lake

Mimeola. The 4.2 acre contributing area would all receive

treatment.


be $88,000.

MI2 - Washington Street Problem Summary

A depression located on the south side of Washington Street in front

of a strip mall located between Disston Avenue and U.S. Highway 27 is

experiencing flooding problems due to inadequate stomter management

facilities. The existing facilities consists of 12" diameter storm

sewer with three inlets outfalling into a ditch running southerly

along U.S. Highway 27. A site investigation revealed that the

existing system was completely clogged. Maintenance efforts to clean

the system have been unsuccessful. Ponding with depths up to

approximately three feet along Washington Street and the mall parking

lot have been reported.

~ecommended Capital Improvements. Due to continuing problems with

maintenance efforts, installation of a storm sewer system to treat

and convey flow to the existing ditch running southerly along u.S.

Highway 27 is required. Water quality treatment and peak flow

attenuation can be achieved through the placement of a control

structure in the ditch.


be $175,000.

City of Umatilla

UM.1 - Seminole Street Problem Summary

An existing swale and culvert system within a res.identia1 development

is experiencing erosion problems. This system runs west from the

intersection of Seminole Street and Winogene Avenue to the

intersection of Seminole Street and Ogden Avenue. At this point, the

system runs to the south along Ogden Avenue outfalling into a pond

located northeast of the intersection of Ogden Avenue and Ocala

Street. Site visits indicate that the erosion is probably due to the

lack of uniform vegetative cover and steep grades. Reports of road

overtopping have not been recorded. A major storm event could result

in extensive erosion along with road overtopping and possibly flooding

of sur'rounding homes.

Recommended Capital Improvements. A closed storm sewer system was

costed at the request of the City. This involves replacing the

existing swale and culvert system with a storm sewer system and

using the downstream pond system, with alterations, as a wet

detention system.


be $335,000.

UM2 - Lakeside Avenue Problem Summary

Frequent road flooding has been reported along Lakeside Avenue and

Argyle Drive to the intersection with Trowell Drive. Located along

the eastern shoreline of Lake Umatilla, the existing stomwater

facilities consist of standard curb and gutter along with inlets

discharging directly into the lake. The system serves approximately

210 acres of contributing area. A site investigation revealed that

the existing system was completely clogged. Maintenance efforts to

clean the system have been unsuccessful. During storm events, runoff

ponds on the road until the curb is overtopped and then flows across a

grassed buffer zone prior to entering the lake. This results in a

reduction in the level of service of the road.

Recommended Capital Improvements. Replace the four outlet

structures with flumes and construct a treatment swale parallel to

the lake. Size the swale to treat half the DCIA in the

contributing area. This is all the retrofit possible unless soils

data indicate that exfiltration can be used.


be $133,000.

Town of Astatula

NO problem areas requiring capital improvements have been identified at

this time.

Town of Hmy-in-the-Hills


this time.

Town of Lady Lake

LL1 - Oak Grove SuWivision Problem Surmnarv

A land-locked retention/detention pond located within the Oak Grove

suWivision near the intersection of U.S. Highways 27 and 441 is

experiencing flooding problems. The pond stage is regulated by a pump which delivers the runoff to an irrigation system for disposal through

land application. The existing pump does not have the capacity to

properly regulate the pond stage, resulting in flooding of the

immediate area surrounding the pond. No reports of runoff entering

adjacent homes has been recorded.

Recommended Capital Improvements. A larger pump and pressure tank

has been recommended by others to regulate the pond stage.


be $30,000.

Town of Montverde


this time.

For water quality problem area identification, various federal, state, and

local agencies were contacted for stomter quality data, reports, and

studies. The FDER water quality reports are examples of studies which

preliminarily address non-point source water quality.

Very little non-point source, or stomter-related data exist; however,

long-term declines in ambient water quality of lakes/streams coupled with

identification of drain wells and sinkholes were used to identify potential

non-point source impacts to surface and groundwater resources. Figure 6-2

shows known drain well and sinkhole locations, saltwater intrusion zones,

and lakes/streams with a known decline in ambient water quality. Table 6-2

presents the location of these features with the respective basin and

sub-basin. These are discussed in further detail below. CDM also

evaluated non-point source pollutant loads from four major pollutants to

twelve major lakes in the County to identify general magnitudes of

non-point source pollutant loads. This analysis was presented in

Section 5.0.

Potential long-term water resource problem areas were identified by

interviews, available water quality data analyses, non-point source loading

analysis, saltwater intrusion trends, and facilities which discharge

stomter to groundwater.

These problem areas have been grouped as one category due to their complex

nature. It is difficult to recommend specific structural solutions for

these areas since detailed evaluations are required to properly alleviate

the problems; however, in many cases, non-structural controls such as land

use, development, or recharge requirements are a sound "first-stepu toward

a comprehensive solution. The County's proposed Stormwater Management

Ordinance addresses these issues. The following paragraphs list the types of problems and types of solutions that are recommended to be analyzed in

detail during future phases of the County's Stornmter Management Program.

0z7=77-,

miles

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LEGEND

e DRAIN WELL LOCATIONS

A STREAM TO SINKHOLE

PROBLEM LAKES

SALTWATER INTRUSION TO FLORIDAN AQUIFER

NOTE: FOR A LIST OF THE PROBLEM AREAS, REFER TO THE WATER QUALITY PROBLEM AREA

WATER QUALITY PROBLEM AREAS

en vironrnen to1 engineers, scientists. ,p/anners. & management consultants CDM-

FIGURE 6-2

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STREAM TO SINKHOLE

TWO stream-to-sinkhole locations have been identified in Lake County.

These are Wolf Branch Sink and the Shocklee Heights Area Sink (Figure 6-2).

These are locations where flowing streams discharge directly into the Floridan Aquifer, which is the local drinking water supply. As a result, pollutants from urban runoff can enter the aquifer and contaminate it. In addition, lack of land use controls around the sinkhole can also allow

other pollutant inflows from industry or septic tanks. Therefore, a

treatment pond, located immediately upstream of the sinkholes, coupled with

land use controls and conservation areas preservation, are sound approaches

to control this problem.

DRAIN WELLS

There are eight drain wells in the County as identified by the USGS and

interviews. These were shown in Figure 1-5. They are used for the following: two for lake level control, two for stormwater discharge, and four for heat pump return flow. Like sinkholes, drain wells allow stormwater pollutants to enter the Floridan Aquifer. Similar land use controls, and a detention pond system will help to mitigate potential

aquifer contamination. The best solution for drain wells is to discourage, or even prohibit, their use. The lake level and stormwater discharge wells are recommended to be evaluated in the future phases of the Countyts

Stomter Management Program to see if flood waters can be diverted to

treatment areas rather than discharged into the aquifer or if upstream

treatment facilities are warranted. The four heat pump return flow wells

could be used for irrigation depending on the quality of the effluent. For all cases, interactions with the lori id an Aquifer should be limited to properly treated recharge and potable withdrawals.

SALrnTER INTRUSION

Saltwater intrusion to the Floridan Aquifer has been documented in the form

of elevated chloride concentrations in the northeast portion of the County

in the St. Johns River and Wekiva River basins. This is a very complex issue that is being considered by the SJRWMD as part of regional

groundwater evaluations. Therefore, the County should pursue

non-structural controls such as land use restrictions and recharge

requirements until firm approaches are defined by the SJRWMD.

W(E WATER QUALITY DECLINE

Ambient water quality analysis by others and CDM indicate that several

lakes are experiencing declines in water quality. As discussed earlier,

Lake ~eauclair, Lake Dora, and Lake Griffin appear to have poor water

quality, while Lake Eustis is borderline between fair and poor. The State of Florida SWIM Program is separately studying the complex problem of Lake

Apopka. Solutions to these water resource problems will require long-term,

detailed solutions. However, certain BMP options can be pursued sooner,

such as the following:

o When stormwater facilities are retrofitted or replaced in a given

area, every effort should be made to provide retrofit treatment;

o Septic tanks should be discouraged wherever regional sewer service

is a viable option; and

o Regulation of lake levels by keeping lakes high for dry season

navigation and low for wet season flood control is the opposite of

what is necessary to propogate wetland species, allow for littoral

zone uptake of settlable pollutants, and promote fishery habitat.

The regulation schedule for the chain of lakes is currently being

restudied by the SJRWMD along with an accompanying socio-economic

study by the University of Florida; these studies will allow the

County to better understand the options for structural changes to

the systems.

6.2.3 NON-PROBLEM FACILITIES

Detailed hydrologic and hydraulic analyses, as performed in Watershed or

Basin Plans, are required to properly evaluate capacity versus demand for

facilities not associated with known problems. Stormwater facility

capacity varies depending upon acceptable limits of flooding, facility

condition (maintained versus non-maintained), and facility design

parameters such as size or diameter, headwater versus tailwater

relationships, length, slope, and friction/local loss coefficients.

Facility demand will vary depending on design storm frequency, intensity,

and duration, as well as land use imperviousness and initial hydrologic

conditions (water table levels and degree of soil saturation). Flow (or

demand) hydrographs, and peak flows, are generated for routing analysis

through stormwater facilities. These routing analyses are accomplished

through computer models, design nomographs, and/or hand calculations. For

the problem areas in Section 6.2.1, this procedure was followed. Thus, to perform a thorough evaluation of capacity and demand for non-problem area

stormwater structures in Lake County, a detailed hydrological and hydraulic

assessment is required. This type of assessment is more involved than the

planning type of assessment required for the State's Comprehensive Plan,

and this studyf s requirements.

However, at this planning level capacity versus demand can be evaluated for

non-problem area facilities in the County by screening historic rainfall

records for the rainfall gages previously identified in Section 3.0. These

recent historic storms can then be compared with design storm frequencies,

durations, amounts, and intensities to identify the minimum level of

service provided in a given geographic area.

This type of assessment is based on the County enforcing the proposed

County Stormwater Ordinance, which requires that peak stormwater rates form

a developed area be equal to or less than the peak stormwater rate prior to

development. With the enforcement of said ordinance, Lake County will be

provided with the same future level of service as currently exists in the

County.

Maxirmun storm amounts and intensities (where available) were identified for

the more recent of these historic storms. able 3-3 showed the results for the historic storm analysis which indicate that facilities not associated

with problems in the County are currently providing at least a 5-year

frequency, 24-hour duration water quantity Level Of Service. The Clermont

area is currently providing at least a 10-year Level of Service based on a

recent 6.9 inch rainfall event. As stated previously, by the County

enacting their Stormwater Management Ordinance, this level of service

should remain for future conditions. A more detailed water quantity Level

of Service analysis is recommended to be provided for each basin as future

Basin Plans are performed.

7.0 COMPUTER MODEL COMPARISONS

This section presents a comparison of water quantity and quality computer

models, which the County may consider to implement to monitor future level

of service and stornwater system impacts due to growth-related or system

alternations impacts.

7.1 WATER OUANTITY MODELS

7.1.1 WATER QUANTITY MODEL COMPARISON ITEMS

Water quantity computer models which could be used by the County were compared based upon the following items:

o County goals, perspectives, and training (e.g., level of detail, model updating, permitting needs)

o Model credibility

- Technically correct with demonstrated performance

- Peer acceptance

- Ability to simulate realistic conditions

o Public domain

o Suitable for microcomputer applications

o Flexible and adaptable

o User-friendly within the limits of data constraints

o Quality of documentation

o Maintenance of model by model developers

- User groups

- Periodic model updating and enhancements

o Applicable to the study area

- Represents key elements of stormwater management system (irregular and/or regular cross-sections, culverts, storage elements, boundary conditions, etc.)

- Calculates flows, velocities, and water surface elevations

- Handles backwater and surcharged pipe flow conditions

- Handles flow reversals and interconnections

- Can perform dynamic simulations of watershed-wide impacts

- Can represent small basins (tens of acres) as well as large basins (hundreds to thousands of acres)

7.1.2 AVAILABLE WATER QUANTITY MODELS

The following paragraphs briefly discuss the water quantity model packages

considered. Key excerpts are taken from the respective mgdel handbooks:

o The USACOE Hydrologic Engineering Center (HEC) Models 1 and 2

"The HEC-1 model is designed to simulate the surface runoff response of a river basin to precipitation by representing the basin as an interconnected system of hydrologic and hydraulic components. Each component models an aspect of the precipitation-runoff process within a portion of the basin, commonly referred to as a sub-basin. A component may represent a surface runoff entity, a stream channel, or a reservoir. Representation of a component requires a set of parameters which specify the particular characteristics of the component and mathematical relations which describe the physical processes. The result of the modeling process is the computation of streamflow hydrographs at desired locations in the river basin."

"The HEC-2 model is intended for calculating water surface profilesfor steady gradually varied flow in natural or manmade channels. Both subcritical and supercritical flow profiles can be calculated. The effects of various obstructions such as bridges, culverts, weirs, and structures in the flood plain may be considered in the computations. The computational procedures is based on the solution of the one-dimensional energy equation with energy loss due to friction evaluated with Manning's equation. The computational procedure is generally known as the Standard Step Method. The program is also designed for application in floodplain management and flood insurance studies to evaluate floodway encroachments and to designate flood hazard zones. Mso, capabilities are available for assessing the effects of channel improvements and levees on water surface profiles. Input and output units may be either English or Metric."

o The USDA SCS Technical Release (TR) 20 and TR-61 Models

"The TR-20 computer program assists the engineering in hydrologic evaluation of flood events for use in analysis of water resource projects. The program is a single event model which computes direct runoff resulting from any synthetic or natural rainstorm. There is no provision for recovery of initial abstraction or infiltration during periods of no rainfall. It develops flood hydrographs from runoff and routes the flow through stream channels and reservoirs. It combines the routed hydrograph with those from tributaries and computes the peak discharges, their times of occurrence, and the water surface elevations at any desired cross section or structure. Any one of the above items can be printed out as well as discharge hydrograph elevations, if requested. The program provides for the analysis of up to nine different rainstorm distributions over a watershed under various combinations of land treatment, floodwater retarding structures, diversions, and channel work. Such analysis can be performed on as many as 200 reaches and 99 structures in any one continuous run. The program uses the procedures described in the SCS National Engineering Handbook, Section 4, Hydrology (NEH-4) except for the reach flood routing procedure."

"TR-61, commonly called WSP2 (Water Surface Profile 2), can aid in &aGtermination of flow characteristics for a given set of stream and flood-plain conditions. More specifically, it can compute water surface profiles in open channels. The program also can estimate head losses at restrictive sections, including roadways with either a bridge opening or culverts."

o Advanced Engineering Technology (AET) Santa Barbara Urban Hydrograph (SBUH), SCS Unit Hydrograph (SCS UNIT), and Interconnected Pond Routing (adICPR) Models

"The SBUH package is used to generate stormwater runoff hydrowphs. Up to 200 sub-basins can be simulated simultaneously with an option to compute and store composite hydrographs. SBUH uses the Soil Conservation Service (SCS) curve number for infiltration losses and incorporates directly connected impervious areas. Rainfall is based on non-dimensional mass curves stored on disk files or keyed in directly."

"SCSUNIT is a program that uses the SCS (Soil Conservation Service) Unit Hydrograph Method to compute up to 100 runoff hydrographs at a time for small watersheds. Rainfall excess is computed using the SCS Curve Number and infiltration formula. It is then applied to a unit hydrograph (based on basin characteristics, and shape factor) to obtain runoff throughout the storm duration. The program requires physical input data for each basin as well as control data that are applied to all basins for which hydrographs are to be computed. Basin Shape Factors (and their corresponding unit hydrographs) can be selected from a standardized table, or input directly by the user. Standardized non-dimensional rainfall distributions can be input in similar

fashion. Therefore, the program keeps input data to a minimum, resulting in ease of use and a reduction in chances for erroneous data transcription. Outputs from the program are varied, providing for flexibility in previewing data before printing and for structured easy-to-use hardcopy. SCSUNIT also includes an output routine that loads summary and hydrograph ordinates to a disk file for use by other programs."

"adICPR is an interactive software package designed to route flood h-raphs through single pond systems as well as multiple interconnected ponds, lakes, or reservoirs. The input and edit routines allow for easy construction of complex networks, including both dendritic and looped systems. Factors such as time-variable tailwater conditions, submergence flow reversal and multiple boundary conditions are integrated into the solution algorithm. Pond connections can be made with sharp and broad crested weirs; gates and orifices; circular, elliptical, arch and box culverts; trapezoidal and parabolic channels; risers (i.e., weirs in series with either culverts or channels); and, rating curves. Physical parameters of individual connections are simply keyed in, with complicated hydraulic computations performed internally by adICPR.It

o CDM RUNOFF

CDM RUNOFF is a modified version of the RUNOFF Block of the USEPA Stormwater Management Model (SWMM) by Camp Dresser & McKee (CDM, 1970 and June 1988). The program simulates the rates of runoff developed from subareas using a kinematic wave approximation. Hydrologic routing techniques are then used to route the overland flows through the pipe, culvert, channel, and lake network as required. Program results can be saved for input to the EXTRAN Block of SWMM to perform hydraulic routing in downstream reaches.

RUNOFF was originally developed in 1970 as part of the original USEPA Stormwater Management Model ( S W M M ) . The program has been applied many times since its inception and has gained world-wide acceptance. Over the years, the program has undergone many changes and modifications although the main formulations and calculations remain mostly unchanged from the original codes.

Program modifications were performed by CDM to streamline program functions and expand channel/lake routing capabilities for use in stormwater master plan studies. Many of the modifications made to the code are derived from a version of RUNOFF previously developed by CDM (MSSM, 1986). A more complete documentation on the model's background and theory can be found in the USEPA SWMM Userts Manual.

The basic overland flow and channel routing calculations remain unchanged in this version of RUNOFF, the program will accept input data sets for the USEPA SWMM RUNOFF program. CDMts version of RUNOFF has the following added features:

- Compatibility with IBM PCs and other IBM compatible microcomputers;

- Runoff hydrograph routing through lakes;

- Runoff hydrograph routing through channels with irregular cross sections;

- Ability to specify a maximum volume of rainfall which can infiltrate into the soil (total soil storage in inches);

- Resizing of pipes and trapezoidal channels to convey peak flows ;

- Diversion of surcharged flows to relief pipes/channels;

- Input of constant baseflow to pipes, streams, and channels;

- On-screen printout of the simulation percentage of completion; and

- Summary tables of peak subarea runoff and other modifications to program output.

0 CDM EXTRAN

CDM EXTRAN is a modified version of the EXTRAN BLOCK from EWMM 111.0. CDM revisions were used as the basis for the SWMM IV EXTRAN Block, (CDM, 1975 and August 1988).

EXTRAN is a hydraulic flow routing model for open channel and/or closed conduit systems. It uses a link-node (conduit-junction) representation of the drainage system in an explicit finite difference solution of the equations of gradually varied, unsteady flow. EXTRAN receives hydrograph input at specific junctions by disk file transfer from a hydrologic model such as RUNOFF or TR20, and/or by manual input. The model performs dynamic routing of stormwater flows through the major storm drainage system to the points of outfall to the receiving water system. The program will simulate branched or looped networks, backwater due to tidal or non-tidal conditions, free-surface flow, pressure flow or surcharge, flow reversals, flow transfer by weirs, orifices and pumping facilities, and storage at on-line or off-line facilities. Types of conduits that can be simulated include circular, rectangular, horseshoe, elliptical, and baskethandle pipes, plus trapezoidal or irregular channel cross-sections. Simulation output takes the form of water surface elevations and discharges at selected system locations.

mTR?iN was developed for the City of San Francisco in 1973. At that time it was called the San Francisco Model or the WRE Transport Model. In 1974, EPA acquired this model and incorporated it into the SWPlM package, calling it the Extended Transport Model - EXTRAN - to distinguish it from the TRANSPORT

Module developed by the University of Florida as part of the original SWMEl package. Since that time, the model has been refined, particularly in the way the flow routing is performed under surcharged conditions and in large open channel networks. Also, much experience has been gained in the use and misuse of the mode 1.

Several enhancements to EXTRAN have been achieved since SWMM 111.0 was released in 1981. These are summarized as follows:

- Input and simulation of channels with irregular cross-sections from select HEC-2 data cards;

- Variable stage-area junctions;

- pump curves;

- ~ifferent boundary conditions at each system outfall;

- "Hot-start" input and output from binary files; and

- On-screen printout of the simulation percentage of completion.

In addition, minor changes to several algorithms were performed for program efficiency and accuracy. All changes were structured to allow the model to read input data sets developed from SWMM 111.0.

o HSP-F The Hydrologic Simulation Program - FORTRAN (HSP-F) HSP-F is a comprehensive package program designed for continuous simulation of watershed hydrology and receiving water quality. HSPF was developed from the Hydrocomp Simulation Program (HSP) which includes the Agriculture Runoff Management (ARM) model (Donigian and Davis, 1978) and the Non-Point Source (NPS) model (Donigian and Crowford, 1976) for runoff simulation, and incorporates the SERATRA model (Onishi and Wise, 1982) for the sediment transport, pesticide decay, sediment-contaminant partitioning, and risk assessment. The model is fully dynamic and can simulate chemical behavior over an extended period of time, using a constant time step selected by the user.

HSPF includes time series-based simulation modules (PERLIND, IMPLND and RCHRES), and utility modules (COPY, PLTGEN, DISPLY, DURANL, and GENER). The simulation (application) modules include mathematics for the behavior of processes which occur in a study watershed. The watershed is divided into three segments which include pervious land, impervious land, and a receiving water system (i.e., a single reach of an open channel or a completely mixed impoundment). The module PERLND simulates the pervious land segment with homogeneous hydrologic and climatic characteristics, including snow accumulation and melt, water movement (overland flow, interflow and groundwater flow), sediment erosion and scouring, and water quality (pesticides, nutrients). The IMPLND

module simulates the impervious land segment where little or no infiltration occurs. The IMPLND processes include snow and water movements, solids, and water quality constituents. The module RCHRES simulates the segment of receiving water body, including hydrologic behavior, conservative and non-conservative constituents, temperature, sediments, BOD and DO, nitrogen, phosphorus, carbon, and pH. The utility modules perform "house-keeping" operations, designed to provide the user flexibility in managing simulation inputs and outputs. For example, the COPY module manipulates time series.

7.1.3 WTER QUANTITY MODEL RECOMMJWDATIONS

Table 7-1 shows the comparison of the available water quantity models based

on the previously identified screening items. Based upon the model

screening and CDMfs experience, CDM recommends the use of the RUNOFF and

EXTRAN models for future water quantity evaluations.

It should also be noted that the methods used in the RUNOFF/EXTRAN package

will utilize the following methodologies to ensure consistency with other

accepted approaches which may be applied by various engineers during permit

reviews :

o Runoff excess computations based on the Horton equation with total

soil storage constraints which can be related to SCS curve numbers

(similar to TR-20 and HEC-1);

o DCIA evaluated as a separate flow surface (similar to HEC-1 and

SBUH ) ;

o Overland flow routing by a kinematic wave with Manning's equation

coefficients (similar to HEC-1);

o Simple, hydrologic routing in RUNOFF by the storage-indication

method (similar to TR-20 and HEC-1);

o Simple, channel routing in RUNOFF by a kinematic wave approach

(similar to TR-20);

TABLE 7 - 1

WATER QUANTITY MODEL SCREENING MATRIX

DIRECTLY BASE 6 l O R NON-PDINT CLOSED REGULAR 6 MULTIPLE VARIABLE FLOW MASS. PRINTS MULTIPLE CONNECTED DRY SOURCE CONDUITS IRREGULAR HYDRAULIC STAGE- REVERSALS ENERGY. 6 FLOUS. REPORTS TOTAL

MOOEL HYDROGRAPH MULTIPLE IMPERVIOUS PERVIOUS WEATHER POLLUTION 6 CROSS- BOUNDARY AREA 6 INTER- MOMENTUM STAGES, 6 INUNDATED CONTINUOUS NUMBER PACKAGE INFLOWS HYETOGRAPHS AREAS AREAS FLOWS C A P A B I L I T Y BRIDGES SECTIONS CONDITIONS JUNCTIONS CONNECTIONS SOLUTIONS VELOCIT IES AREA C A P A B I L I T Y

CDM RUNOFF1 YES YES YES YES YES YES YES YES YES YES YES YES YES YES YES 1 5 EXTRAN

SCS TR-20/ YES YES NO YES YES NO YES YES NO YES NO NO NO NO NO 7 TR-61

USACOE YES YES YES YES YES NO YES YES NO YES NO NO YES NO NO 9 HEC-11 HEC-2

AET SCSUNIT I YES YES YES YES YES NO YES YES YES YES YES NO YES NO NO 11 S B U H l a d I C P R

HSP-F YES YES YES YES YES YES YESlNO YESlNO NO YES NO NO YES NO YES 1 0

o HEC-2 irregular cross-section format capability in both RUNOFF and

EXTRAN; and

o Variable stage-area relationships in both RUNOFF and EXTRAN.

7.2 WATER QUALITY MODELS

NON-POINT SOURCE (NPS) WATER QUALITY MODEL

To evaluate non-point pollution loading targets and associated management

options, it is important that the planning tools (i.e., water quality

models) be compatible with the complexity of the water quality problems,

important management issues, and the available water quality monitoring

database. A non-point pollution management plan is not necessarily more

technically defensible just because it relies upon a more complex water

quality model, particularly, if the model complexity is inconsistent with

the management issues, or there is insufficient water quality monitoring

data available to calibratefierify model parameters and to demonstrate its

credibility to decision-makers. In fact, the less complex model which is

compatible with the available data and the level of accuracy required to

compare watershed management options is usually the preferable planning

tool.

If the instream travel times are long enough to produce significant decay

and transformation of non-point pollution loadings before they reach the

critical receiving water, we generally recommend the use of non-point

pollution loading models which include instream transport. If instream

travel times are short, the recommended model need not have instream

transport capability. In Lake County, the ultimate model package used for

future evaluations should have the capability to route pollutants through

lakes since much of the County is comprised of lakes. Further evaluation

of data availability and adequacy is required to recommend a master

planning water quality model in Lake County; however, CDM has developed a

Non-Point Source (NPS) Spreadsheet model which can be used with pollutant

loading factors to screen overall trends (annual pollutant loads). For

this report, the NPS spreadsheet model was used to evaluate ultimate water

quality model recommendations in Lake County (see Section 5). The following paragraphs provide a brief description of the CDM-WS model.

NPS SPREADSHEET MODEL

The NPS Spreadsheet model simulates annual non-point pollution loadings

from local rainfall statistics. The model relies upon Event Mean

Concentration (EMC) factors for different land use categories to calculate

pollution loadings. Because this model is spreadsheet-based, it can be

quickly applied to screen the pollution loading in order to identify and

rank water quality problem areas by priority.

For future water quality evaluations in Lake County, the Spreadsheet model

could be used to screen a series of management options to determine which

options warrant further evaluation through the use of a continuous water

quality model which includes instream transport capabilities. In this manner, the number of management options can be reduced to a reasonable

number for detailed study.

8.0 LEVELS OF SERVICE

Stormwater management has become a complex community issue. In the past, ditching and draining to convey stormwater away from development was the

accepted practice and allowed access to much of Florida.

Over the years, adverse impacts to fisheries, scenic areas, and wildlife

habitats have enlightened accepted approaches to manage stormwater.

Stormwater management now involves storage, conveyance, recharge,

conservation, and treatment aspects along with proper timing, durations,

levels of flooding, and nutrient releases for natural areas or wetlands to

ensure a comprehensive management approach to what is a local, State, and

Federal issue.

Lake County is similar in characteristics to other communities regarding

stormwater service. Certain County, City, and private stormwater

management systems provide a degree of flood protection to homes and

streets, and a degree of treatment of the runoff prior to discharge to

receiving waters. As with other communities, stormwater systems were

constructed in a "piece-meal" manner, (i.e., without evaluating overall

system performance) and with little regard to the treatment of stormwater.

To properly implement a stormwater management system, a detailed stormwater

master plan is required and levels of service for the stormwater structures

need to be identified. Proper levels of service (LOS) decisions for water

quantity (flooding) and water quality protection are essential because they

establish the intent of public safety and agency involvement, and set the

goals for the County to satisfy.

WATER QUANTITY

The water quantity LOS decision will drive the size and cost of stormwater

facilities and is an essential decision within the SWMP. Figure 8-1 shows

examples of various water quantity levels of service within a developed

area. For example, Class D provides for flood protection of first-floor

elevations, evacuation routes, and arterial roads, while Class C provides

CLASS A ROADWAY WIDTH (W)

CLASS B

CLASS C

CLASS D

< FIRST FLOOR ELEVATION

control of flood waters to less than 0.5 ft over the arterial/evacuation

road crams. For urban sub-basins, it is likely that a diminishing return

for public expenditures will occur sooner than for new developments due to

space constraints and low-lying first-floor and road elevations.

The water quantity LOS also requires decisions regarding design storms.

This is because stomwater structure design is dependent upon the storm

frequency and duration.

The following storm events are recommended to be used for stomwater

facility design:

Storm Storm Frequency ( YR) Duration (HR) Facility Type

2 2 4 Retentionpetention Basins

24 Retentionpetention Basins and Storm Sewers

2 4 Retentionpetention Basins, Canals, Ditches, and Culverts

25 96 Landlocked Areas

50 24 Bridges

24 First Floor Elevation Must be 18" or Above

These storm events and facility types are consistent with the County's

draft Stormwater Management Ordinance. Recommended rainfall distribution,

amounts, and intensities to be used for basin-specific design storm

evaluations as part of subsequent permitting and stornrwater program phases

were previously presented in Table 3-1. These values are based on an SCS

Type 111 distribution (formerly called the Type II-modified) and SJRWMD

Technical Publication SJ 88-3. Values for design events not included in

this publication were derived by a least squares regression of provided

values.

8.2 WATER QUALITY

Water quality LOS is generally based on "first flush'' abatement of

pollutants for new developments (Figure 8-2). Retrofit LOS is often

established separately due to space and financial constraints. In general,

water quality retrofits are required if flooding solutions are implemented.

For this reason, achievable water quality LOS for retrofit facilities will

be case-specific. For subsequent Stormwater Management Program Phases,

priorities for pollutant loads should also be considered in the eventual

choice for water quality LOS.

8.3 SUMMARY

LOS should be established to be consistent throughout the County; however,

it is often difficult to apply new development criteria to existing problem

areas. The problem area solutions in Section 6.0 attempt to provide new

development LOS wherever possible. The historic storm analysis in Section

3.0 indicates that facilities not associated with problems in the County

are currently providing at least a 5-year frequency, 24-hour duration water

quantity level of service. The Clermont area is currently providing at

least a 10-year level of service based on a recent 6-9 inch event.

Therefore, existing systems should be retrofit to provide at least a Class

D 5-year LOS consistent with the historic storm analysis in Table 3-3. New

development LOS is recommended to satisfy the requirements of the County's

Draft Stormwater Management Ordinance (Class D, 100-year LOS). Where

possible and with reasonable financial constraints, existing systems should

be retofit to the Ordinance requirements as well.

Participation by the public and the regulatory agencies is critical to the

implementation process. The public must decide on the LOS they desire and

are willing to fund. In urban areas, trade-offs of flood protection and

water quality enhancement for park alterations may need to be considered.

The regulatory agencies need to consider alternative solutions and balance

net positive effects of the project versus potential negative impacts.

*THE "FIRST-FLUSH" OF RUNOFF FROM THE CONTRIBUTING AREA RECEIVES TREATMENT PRIOR TO DISCHARGE TO RECEIVING WATERS DEPENDING ON TREATMENT TYPE.

5 5 m m L o0

$ r : 3 I C) m

3 3 ? 5 9 2 e ; 3: 9 a G 3 3 5' (D (D : 4 0

8 :: 2 5 2 2 9 a c; .T

0

CONTRIBUTING AREA

8.4 PRIORITIZATION

Priori t ies are necessary to ensure that acute needs are dealt with as soon

and eff iciently as possible. This section presents pr ior i t ies for

solutions to problem areas identified to-date, and pr ior i t ies for basin

studies within the Stormwater Master Plan.

9.0 RECOMMENDATIONS

Presented below is a summary of the non-structural and structural

improvements recommended for Lake County. These recommendations will allow

the County to commence the implementation of a Stomter Management

Program to protect public safety, protect groundwater recharge, properly

manage wetlands, and enhance water quality in Lake County, while allowing

the County to meet regulatory agencies1 criteria.

on-structural improvements are items which do not require physical

improvements, such as regulations or actions required to implement the

improvements to the County's stomwater management system. Non-structural improvements include the setting of goals, objectives, and policies (per

the State's 95-5, FAC criteria). These include action items, stomwater

regulations and ordinances, and maintenance practices. Each of these non-structural improvement categories is discussed below.

9.1.1 GOALS, OBJECTIVES, AND POLICIES

In coordination with this report, and per the State's 95-5, FAC

requirements, Lake County has developed a set of Stomwater Management

goals, objectives, and policies. The County's Stomwater Management goal, as stated in the County's Comprehensive Plan, is:

"Lake County shall provide sound stomwater, surface water, and groundwater resource management to prevent flood damage and protect water quality to ensure the safety and well being of the citizens of Lake County. "

In order to fulfill this goal, the County identified four objectives and

established 37 policies to follow. The four objectives are presented

below.

OBJECTIVE 1: CORRECT EXISTING DEFICIENCIES. Lake County shall

identify and correct existing facility deficiencies on a priority

basis. The County shall address known problems such as flooding and

degradation of surface and groundwater quality.

OBJECTIVE 2: GUIDE FUTURE DEVELOPMENT. Lake County shall manage and

coordinate its stormwater review and implementation process to address

the needs of future development.

OBJECTIVE 3: MAXIMIZE FACILITY USE AND DISCOURAGE INEFFICIENT LAM)

USE. Lake County shall maximize the use of existing stormwater - management facilities and available capacity, and promote efficient

land utilization through the implementation of appropriate technology.

OBJECTIVE 4: PROTECT THE FUNCTIONS OF NATURAL FEATURES. Lake County

shall 1) minimize the occurrence of flooding that is a threat to human

health or property; 2) identify and prohibit drainage wells; and 3)

improve its ability to manage stormwater so as to minimize the

degradation of surface water in order to protect the functions of

natural features.

The 37 policies required to be implemented by the County to satisfy the

four objectives are contained in Appendix A (Lake County's Stormwater

Sub-Element, Chapter V1-C, of the County's Comprehensive Plan) of this

report.

9.1.2 STORMWATER MANAGEPENT REGULATIONS AND ORDINANCES

Lake County is currently in the process of adopting a Stormwater Ordinance.

The draft ordinance provides the mechanism for the County to enforce its

stormwater management objectives in order to fulfill the stormwater goal.

As presented in Section 4.0, the draft Stormwater Management Ordinance will

be the most comprehensive stormwater ordinance in Lake County, when

compared with other municipal ordinances within Lake County. The County's proposed ordinance defines required levels of service for stormater

facilities, provides design criteria to be followed in implementing

stormwater improvements, and requires the identification of a suitable

entity to perform maintenance on the stomter facilities. Appendix C presents a copy of the County's draft Stomter Management Ordinance.

Based on these merits, it is recommended that the County adopt its draft

Stomter Management Ordinance. Local cities and towns within the County

are encouraged to adopt similar ordinances. As presented in Section 4.0,

the cities and towns within Lake County do not have as stringent stormwater

management regulations as those currently being proposed by Lake County.

9.1.3 MAINTENANCE PRACTICES

Proper operation and maintenance of stormwater management facilities is

essential to the facilities providing the design levels of service. These practices are also usually specific to a given county or city. For this

reason, operation and maintenance practices were evaluated based on

interviews with County and various City staff regarding regular practices.

Currently, County facilities are maintained on an as-needed basis as time

and manpower allow. Likewise, the cities in the County perform maintenance

on an as-needed basis. The problem with this approach is that silt,

debris, and some harmful vegetation can accumulate to the point where a

problem that could have been avoided occurs during a large storm.

Thus, it is recommended that a regular maintenance schedule should be established and budgeted for each year by the County. Once implemented on

a regular basis, this maintenance program would not only improve the

consistency of level of service, but would also demonstrate to the citizens

that their tax dollars are working for them. Table 9-1 outlines

recommended frequencies for maintenance by facility type. Based upon these

recommended maintenance practices, a cost estimate to provide this level of

maintenance was performed. Table 9-2 presents the results of the cost

estimate evaluation. As shown in Table 9-2, approximately $1,775,000 of

annual expenditures are estimated to be required.

TABLE 9-1

RECOMMENDED MAIN!ElWNCE FREQUENCIES BY FACILITY TYPE

FACILITY TYPE MAINTENANCE FREQUENCIES

1. Storm Sewers and Culverts Annual inspections and silt/debris removal a t l eas t every two years.

2. Retentionpetention Ponds Annual structure inspection. S i l t removal every four years. Mow grass two or three times annually.

3. Bridges Annual inspection for structural s t ab i l i ty and erosion.

4. Canals, Ditches, and Swales Annual inspection for erosion and mowing two or three times annually. Removal of silt and sediments a t leas t every five years.

n a l n t e n a n c e T y p e

S w a l e n a l n t e n a n c e ( s e d l m e n t r e m o v a l e v e r y 5 y e a r s l C u l v e r t n a t n t e n a n c e

r e m o v a l e v e r y 5 y e a r s l C u l v e r t Rep l acemen t ( r e p l a c e e v e r y 30 y e a r s )

( 3 3-man c r e w s ) E q u l p m e n t Rep l acemen t ( s e e b e l o w )

I BASIN TOTAL ( $ 1 COUNTY TOTAL ( $ 1

O k l awaha R l v e r B a s l n

( $ 1

TABLE 9 -2

ANNUAL MAINTENANCE COSTS

MI t h l a c o o c h e e R l v e r B a s l n

( $ 1

U e t l v a R l v e r B a s l n

( $ 1

S t . Johns e l v e r B a s l n

( $ 1

K t s s lmmee R l v e r B a s l n

( $ 1

EQUIPMENT REPLACEMENT COSTS

COUNTY TOTAL

Equ 1 pmen t

G r a d a l l F r o n t End L o a d e r Backhoe ( o n t r a c k s ) Backhoe ( o n t l r e s ) Tandem T r u c k s F l a t - B e d T r u c k s D r a g 1 l n e Vacuum T r u c k

( 1 ) Assumes r e p l a c e m e n t o f equipment e v e r y 1 0 y e a r s ; a v e r a g e I n t e r e s t r a t e o f 101 .

Number

2 2 2 4

1 0 4 1 2

U n l t C o s t

( $ 1

165 .000 80.000

165.000 80.000 60.000 50.000

200.000 150,000

I

C o s t

( $ 1

330 .000 160.000 330.000 320.000 600.000 200.000 200.000 300.000

2.440.000

I

1 A m m o r t l z e d

C o s t s

( $ 1

53.700 26.000 53.700 52.100 97.600 32,600 32.600 48.800

397,100

I

9.2 STRUCTURAL IMPROVEMDJTS

Structural improvements are physical improvements to the County's

stomwater management system, along with the associated evaluations, field

information, and investigations required to implement the improvements.

9.2.1 PROBLEM AREA IMPROVEMENTS

Table 9-3 presents a summary of the problem areas identified in Section

6.0. The summary includes a probable cost for the recommended improvements

and a preliminary categorizing (as serious or nuisance based on the

definitions in Section 6.0) and ranking of the problem areas. The

preliminary categorizing of the problem areas is defined as:

o High Priority (Serious) - potential to endanger life and/or potable water supplies;

o Medium Priority (Serious) - potential to endanger property and/or environmentally vital areas; and

o Low Priority (Nuisance) - potential to cause minor damage to property, inconvenience, or unsightliness.

Of the 19 problem areas, 11 have been identified as high priority, 8 as

medium priority, and none as low priority. The projects are listed in a

preliminary ranking based on available information regarding severity of

the problem and the need for immediate solutions. The phased CIP should

consider land acquisition first, especially around Wolf-Branch sink and the

drainwells not associated with heatpumps. As shown in Table 9-3, the total

cost to implement the structural improvements is projected to be

$1,696,000. As stated previously in Section 6.0, prior to implementing

these improvements it is recommended that detailed hydrologic and hydraulic

evaluations should be performed.

TABLE 9-3

PROBLEM AREA SUMMARY

Preliminary Recommended Capital

Problem Area Ranking Priority (1 Improvement Cost($)

LC1 - Astor Area ' 4 M Sub-Basin Study (2)

LC2 - Lake Yale Dike / 18 M Erosion Protection 16,000

LC3 - Wolf Branch Road / 3 H Widen We i r 31,000

LC4 - Wolf Branch Sink ' 1 H Sub-Basin Study (2)

LC5 - Shocklee Heights Sink / 2 H Sub-Basin Study (2)

GR1 - Groveland High School 5 M Swales & Detention 256,000

GR2 - Gadson Avenue d 11 H Install Headwalls 9,000

GR3 - Baldwin Avenue 8 H 30" RCP & Detention 49,000

GR4 - Sampey Road 19 M Erosion Protection 10,000

GR5 - Mount Pleasant Road / 10 H Sub-Basin Study (2)

GR6 - Park Street J 9 H 3'x4' CBC 25,000

GR7 - Mascotte Park 1 17 M Install Headwalls 23,000

MA1 - Laurel Street 1 7 H Detention Pond 227,000

MA2 - Oaks Street 1 13 M 24" RCP & Detention 288,000

MI1 - Chester Street / 16 M Exfiltration Trench 88,000

MI2 - Washington Street 14

UM1 - Seminole Street / 12

M Closed Storm Sewer & 176,000

Detention

M Closed Storm Sewer & 335,000

Detention

UM2 - Lakeside Avenue ./' 15 M Flumes & Swales 133,000

LL1 - Oak Grove Subdivision 6 M Larger Pumping System 30,000

& Sub-Basin Study (2)

TOTAL $$,696,000(~)

Priorities were assigned as the following:

High Priority (H) - potential to endanger life due to depth of inundated and/or facility failure (e.g., evacuation route or arterial road);

Medium Priority (M) - potential to endanger property and/or environmentally vital areas; and

Low Priority (L) - potential to cause limited damage to property, inconvenience, or unsightliness.

(2) Included in Future Basin Study Recommendations (Section 9.2.3).

(3) The total costs identifiable at this time.

9.2.2 UNKNOWN PROBLEM AREA IMPROVEMENTS

Identification of unknown problem areas is difficult to ascertain at this

planning level. Potential water quantity problem areas can only be

identified through detailed hydrologic and hydraulic investigations, which

are performed during basin studies. However, at this planning level, a

conceptual analysis can be performed to estimate the cost of potential

retrofit improvements which would provide for the treatment of stormwater

in areas where no treatment currently exists. The retrofit improvements

would reduce existing pollutant loads to receiving waters in Lake County.

The retrofit improvements would provide treatment of the directly

connected impervious areas (DCIAs) in Lake County. Since the majority of pollutants is carried in the first inch of runoff from the DCIA, the

treatment of this volume would provide for a cost-effective treatment

facility in urbanized areas, which is where a majority of the areas are

located. For this conceptual analysis, the retrofit treatment facilities

were sized based upon the DCIA within each of the 18 hydrologic sub-basins

and the type of treatment (i.e., retention or wet detention) which could be provided within each sub-basin based on available soils and groundwater

information. Table 9-4 presents the conceptual cost estimate to provide

retrofit treatment of the DCIA in Lake County. It should be noted that no treatment facilities were planned for areas in the Ocala National Forest

except for the area contributary to the Shocklee Heights sink area. It is recommended that these conceptual retrofit facilities be better defined by

performing detailed basin studies as part of the County's overall

Stormwater Management Program.

9.2.3 ADDITIONAL STORMWATER PROGRAM NEEDS

AS stated in the County's Comprehensive Plan, Lake County needs to perform

a Stormwater Master Plan by 1993. This Master Plan is recommended to be

performed on a basin-by-basin basis, that is, a basin study for each of the

five major hydrologic basins. The basin studies would have sufficient

field information to assure that the results of the studies can be

implemented. Field information includes topograhical data for the basin

L C 1 . 9 TABLE 9 - 4 2 2 0 - 6 6 - L A K E 0 5 / 0 9 / 9 1 CONCEPTUAL PROBABLE COSTS FOR

R E T R O F I T TREATMENT F A C I L I T I E S

and field surveying information for major structures. The basin studies

are recommended to be of sufficient detail to allow the study to be

submitted to the Water Management Districts for conceptual permitting

approval. This would include water quantity evaluations and water quality

analysis, with the recommended computer models, and comprehensive

alternatives evaluations which are consistent with the County's goals,

objectives, and policies. Table 9-5 presents the estimated costs to

acquire the topographical and field surveying information, and to perform

the basin studies for each basin. The total estimated cost to acquire the

necessary data and perform the five basin studies is $5,032,000.

9.3 PRIORITIZATION

Areas within the County can be prioritized to ensure that proper solutions

for the problems are determined, that sound guidance is provided for newly

developing areas, that environmentally sensitive areas are protected, and

that public facilities are strategically placed. Priorities for the future

Stormwater Management Basin Studies were established by an equal weighting

of the following considerations:

1. Number and severity of water quantity problem areas in the basin;

2. Number and severity of water quality problem areas in the basin;

3. Predominance of recharge areas;

4. Predominance of wetland areas; and

5. Potential for high growth in the planning period.

Table 9-6 lists the five basins in the County and their respective rank.

The Oklawaha River basin ranked high in all aspects and is recommended to

be studied first. The Withlacoochee River basin, especially the Lady Lake

sub-basin, is the next critical basin for study due to high growth

pressures. Table 9-7 provides a preliminary list of annual and capital

costs per basin. The phasing of specific problem solutions were provided

TABLE 9 - 5

LAKE COUNTY STORMWATER MASTER PLAN B A S I N STUDIES COST ESTIMATE

E s t i m a t e d P r o b a b l e

B a s i n C o s t *

O k l a w a h a R i v e r $ 2 , 4 1 6 , 0 0 0 W e k i v a R i v e r 7 2 8 , 0 0 0 S t . J o h n s R i v e r 9 7 5 , 0 0 0 W i t h l a c o o c h e e R i v e r 8 0 5 , 0 0 0 K i s s i m m e e R i v e r 2 0 8 , 0 0 0

TOTAL ESTIMATED COST $ 5 , 1 3 2 , 0 0 0

----------------------------------------------.-------------------..----- * C o s t i n c l u d e s t o p o g r a p h i c a l c o n t o u r maps a t 2 - f o o t i n t e r v a l s

f o r a r e a s n o t c u r r e n t l y c o v e r e d i n L a k e C o u n t y , f i e l d s u r v e y s f o r m a j o r o p e n c h a n n e l c r o s s s e c t i o n s , a n d s t r u c t u r e d a t a ( i . e . , s i z e , t y p e , i n v e r t s , l e n g t h s , e t c . ) , a n d e n g i n e e r i n g e v a l u a t i o n s .

TABLE 9-6

PRIORITIES FOR STORMWATER MASTER PLANNING BY BASIN

Water Water Quantity Quality Recharge Wetlands Growth

Overall Problem Problem Area Area Change Basin Rank Rank Rank Rank Rank Rank

Oklawaha River 1 1 1 1 1 1

Wi thlacoochee 2 2 2 3 2 2

Wekiva River 3 4 3 2 3 3

St. Johns River 4 3 4 4 4 5

Kissimmee River 5 5 5 5 5 4

ANNUAL MAINTENANCE

C A P I T A L E X P E N D I T U R E S

P r o b l e m A r e a I m p r o v e m e n t s

F u t u r e S t u d l e s a n d F i e l d a n d A e r l a l S u r v e y s

R e t r o f i t I m p r o v e m e n t s

TOTAL C A P I T A L E X P E N D I T U R E S

TABLE 9 - 7

STORMUATER MANAGEMENT PROGRAM PROBABLE COST SUMMARY

I O k l a w a h a U l t h l a c o o c h e e R i v e r B a s i n R l v e r B a s i n

. ($ I ( $ 1

8 8 5 . 0 0 0 3 0 7 . 0 0 0

I U e k i v a S t . J o h n s

R i v e r B a s i n R i v e r B a s i n ( $ 1 ( $ 1

K i s s i m m e e R i v e r B a s i n

( $ 1 TOTALS

( $ 1

in Table 9-3. It is recommended that public information workshops be

conducted to finalize the priority phasing schedule of problem area

improvements and future basin studies.

9.4 ADDITIONAL PROGRAM NEEDS

As Lake County progresses with subsequent phases of its Stormwater

Management Program, the County needs to evaluate its ability to fund and

adminster the program. As shown in Table 9-7, approximately $1,800,000 per

year will be required to provide adequate annual maintenance, and approximately $116,400,000 could be expended to implement identified

capital improvements. To implement this program, efficient administration

of the program and alternative funding sources will be required. Thus, it is recommended that the County conduct a stormwater administration and

financing study to determine the most efficient methods to administer the

program and pursue the creation of an alternative funding source such as a

stormwater utility.

APPENDIX A

Lake County Stormwater Sub-~lement

CHAPTER VI PUBLIC FACILITIES ELEMENT

9J-5.011 (2) F.A.C. Lake County, Florida

Stormwater Sub-Element Chapter VI-C

GOALS, OBJECTIVES, AND POLICIES. This section establishes the Stormwater Sub-Element Goals, Objectives, and Policies for implementation pursuant to Section 95-5.011 (2), Florida Administrative Code.

GOAL 6C: STORMWATER. SURFACE WATER. AND GROUNDWATER MANAGEMENT. ULKE COUNTY SHALL PROVIDE SOUND STORMWATER, SURFACE WATER, AND GROUNDWATER RESOURCE MANAGEMENT TO PREVENT FLOOD DAMAGE AND PROTECT WATER QUALITY TO ENSURE THE SAFETY AND WELL BEING OF THE CITIZENS OF LAKE COUNTY.

OBJECTIVE 6C-1: CORRECT EXISTING DEFICIENCIES. Lake County shall identify and correct existing facility deficiencies on a priority basis. The County shall address known problems such as flooding and degradation of surface and groundwater quality.

Policy 6C-1.1: BlFminate Existina Deficiencies. By 1993, Lake County shall develop specific plans to correct existing stormwater problems in the following priority areas:

1. Wolf Branch Road 2. Shocklee Heights Sink - 3. Astor Area 4. Lake Yale Dike

based upon the Lake County Stormwater Management Needs Assessment completed in 1990.

Policy 6C-1.U: Purchase Wolf Branch Sink. Lake County shall coordinate with the Oklawaha Basin Recreation and Water Conservation and Control Authority in Lake County for the purchase of the Wolf Branch Sink and surrounding land.

Policy 6C-1.2: com~letion of Stormwater Manaaernent Master Plan. Lake County shall complete a Stomwater Management Master Plan by 1993. The County, in coordination with the appropriate Federal and State and Local agencies, shall seek additional opportunities for funding joint projects to facilitate the County-wide Stormwater Management Master Plan.

Policy 6C-1.3: Stormwater Manaaement Ordinance. By 1991, Lake County shall finalize, adopt, and implement the Lake County Stormwater Management Ordinance to establish a sound permitting, construction certification, and enforcement program. The County

VI-C-1 December 21, 1990

Lake County Stormwater Sub-Element

shall continue to pursue delegation of responsibility from the regulatory agencies. Where necessary, the Ordinance shall be as. compatible as possible with the regulatory agencies' regulations.

Policy 6C-1.4: Fundina for Stomwater Manaaement. By 1991, Lake County shall-initiate a stormwater utility or other permanent funding mechanism for funding stormwater improvements. These new funding sources shall be utilized to develop and implement the Stormwater Management Master Plan.

Policy 6C-1.5% Contour Interval Ma~~inq. By 1993, a complete detailed County-wide mapping at one (1) foot contour intervals shall be obtained from the SJRWMD and the SWFWMD. The Federal Insurance Rate Map (FIRM) shall continue to be used as the basis for development review.

Policy 6C-1.6% Priorities for Stormwater Master Planning. Lake County shall set the following basin priorities for detailed master planning: 1) Oklawaha River, 2) Withlacoochee River, 3) Wekiva River, 4) St. Johns River, 5) Kissimmee River. By 1994, Lake County shall develop corrective measures for minimizing or eliminating identified public threats through targeting the portion of the basin evaluated to be of greatest concern.

Policy 6C-1.7: Five Year Schedule of Facilitv Improvements. Within five years after the completion of the Stormwater Management Master Plan, Lake County shall correct or minimize the corresponding set of deficiencies that are identified as priorities in terms of the public's health and safety. Beginning in 1992, Lake County's Environmental Services Department shall, as part of the annual update of the five year Capital Improvements Program, prepare a list of prioritized stormwater improvements. Lake County shall prioritize and correct the deficiencies identified in the Stormwater Management Master Plan through the Capital Improvements Program, with consideration given to the following criteria.

A. The first priority should be given to those deficiencies that threaten health, safety and welfare. This policy shall be interpreted to include drainage wells identified in the Stormwater Management Master Plan that are known to be a public threat to the aquifer or public drinking well water supply.

B. The second priority should be given to those improvements that are necessary to bring the existing substandard systems and subsystems up to the adopted LOS appropriate for each basin with respect to flooding or pollution abatement deficiencies, as reflected by the stated goal or improving current levels of service.

C. The third priority should be given to those improvements that represent opportunities to participate on "joint projects" (with other public or private entities) that will result in the more efficient construction or replacement of improvements over time.



Policy 6C-1.8: Coordination with Adjacent Jurisdictions. Lake County shall cooperate and consult with the 14 municipalities and adjoining counties, in the completion of the Stormwater Management Master Plan and the subsequent identified improvements. Lake County shall encourage the municipalities to enact stormwater management programs which are consistent with State, Regional, and County requirements for new development.

OBJECTIVE 6C-2: GUIDE FUTURE DEVELOPMENT. Lake County shall manage and coordinate its stormwater review and implementation process to address the needs of future development.

Policy 6C-2.1: Im~act Assessment Durina Develomnent Review. By 1992, Lake County shall require, as part of the development review process, an impact assessment that addresses the effects of new development on existing storinwater management systems. This review process shall consider how the stormwater management systems will operate at build-out.

Policy 6C-2-22 8. By 1996, Lake County shall reevaluate the effectiveness of surface water management criteria for swales, open channels, and culverts for their applicability and effectiveness.

Policy 6C-2.3: Review of Land Develo~ment Reaulations. Lake County's Land Development Regulations shall incorporate Stormwater Management Design Standards as contained within the Lake County Stormwater Management Ordinance. These design standards shall include, at a minimum, the following criteria:

A. In new developments, Lake County shall require a retentioddetention system that limits peak discharge of a developed site to the peak discharge from the site in an undeveloped condition for a specified design stonn.

B. Stormwater collected in any development must be managed in a manner that will not cause personal or property damage to upstream and/or downstream property owners;

C. Any segment of a stormwater system which is to be dedicated and made a part of the County's Stormwater System shall be designed to accommodate upstream flows through the system;

D. Each phase of any development shall exist as an independent unit capable of having its surface water management needs met by the stormwater system design; and

E. Wet detention areas shall be designed as limnic systems and measures shall be provided to protect the publics health, safety, and welfare. Where no fencing is present the space shall count as part of the open space requirements.



Policy 6C-2.4: Storwater Convevance Riahts-of-Wav. Lake County shall pursue, if necessary, the acquisition of stormwater rights- of-way andlor easements necessary for the operation and maintenance of the County's stormwater system.

Policy 6C-2..5: Desicm of Stormwater Manaaement Svstems. Lake County shall require that all stormwater management devices constructed be designed to County standards.

Policy 6C-2.6: provide Stormwater Services. Lake County shall provide adequate stormwater services to maintain the adopted level of service standards based upon, but not limited to, the following considerations:

A. The protection and maintenance.of the public's health, safety, and welfare;

B. The protection and maintenance of the property;

C. The protection of existing public investment;

D. The protection of water quality;

E. The reduction of operating and maintenance costs; and,

F. The achievement and satisfaction of Regional, State and Federal regulations.

Policy 6C-2.7: provide Effective Stormwater Treatment. Lake County shall require that plans for expansion, modifications, and replacement of existing development, excluding phased development, meet the adopted level of service, where such stormwater treatment is currently inadequate.

Policy 6C-2.8: Cost Effective Stormwater Manaaement. Stormwater management systems shall employ the most cost-effective pollutant control techniques available that are consistent with sound environmental management and which provide the greatest efficiency in stormwater runoff pollutant removal. A continuing maintenance program shall be approved by the County.

Policy 6C-2.9: Non-Structural Solutions to Stormwater Problems. Lake County shall require that non-structural improvements be utilized to solve existing and future stormwater problems where it is economically and/or physically possible to utilize these approaches. Where structural approaches must be utilized, the County shall ensure that environmental damage is minimized. Non- structural solutions may include the use of conservation areas and maintaining floodplain protection (capacity) through the provision of compensating storage.



Policy 6C-2.10: Desim Storms Level of'service Standards. Lake County hereby adopts the following minimum twenty-four (24) hour level of service standards for design storms:

Facility Type Design Storm ................................................................ Bridges 50 Year

Principal Arterial Bridges 100 Year

Canals, ditches, roadside swales, or culverts 25 Year for stormwater external to the development

Canals, ditches, roadside swales, or culverts 10 Year for stormwater internal to the development

Crossdrains 25 Year

Storm sewers 10 Year

Major DetentiodRetention structures1 For the Probable Maximum Precipitation as required by SJRWMD

Minor DetentiodRetention structures1 25 Year

First floor elevation must be 18" or above the 100 year Flood Elevation

-0- -----.------..-----.------.-----...---.-.--m--..-----...-.-.-

Major/Minor DetentiodRetention Structures are based on Hazard Classification for Dams and Impoundments as defined by the SJRWMD.

-.-.----.----.----..---------.-----..-.----.-.---...----.--.---m

Policy 6C-2.11: Desiun Storm Level of Service Standard for Landlocked Areas. Landlocked areas shall maintain a twenty-five (25) year ninety-six (96) hour design storm level of service standard . Policy 6C-2.12: Stormwater Manaaement for Roadwav Construction. Lake County, in coordination with the Florida Department of Transportation, shall require appropriate or suitable stormwater management systems for the construction or reconstruction of all arterial and collector roadways within the County.

Policy 6C-2.13: Consideration for Natural Hvdro~eriod. Lake County shall consider the natural hydroperiod of receiving waters when stormwater management systems are designed.

Policy 6C-2.14: Accepted Stormwater Run-Off Computer Models. By February 1992, the Lake County Land Development Regulations shall include provisions for the acceptance of computer models which



calculate stormwater run-off. These models shall be limited to those accepted by regulatory agencies.

OBJECTIVE 6C-3: MAXIMIZE FACILITY USE AND DISCOURAGE INEFFICIENT LAND USE. Lake County shall maximize the use of existing stormwater management facilities and available capacity, and promote efficient land utilization through the implementation of appropriate technology.

Policy 6C-3.1: Utilize New Technoloaies. Lake County shall utilize new technologies and operational procedures as they become feasible.

Policy 6C-3.2: Innovative Stormwater Manaaement. The County shall actively participate in the development of innovative stormwater management programs which protect and conserve the County's water resources.

Policy 6C-3.3: Alternative Stormwater Systems. Lake County shall continue to investigate alternative stormwater management systems for providing efficient stormwater management service.

Policy 6C-3.4: Efficient Land Use Desiunations. Lake County shall designate land uses on its Future Land Use Map which incorporate stormwater management without promoting inefficient '

land utilization.

Policy 6C-3.5: Stormwater Manaaement Performance Standards. By February 1992, the Lake County Land Development Regulations shall include the performance standards that are contained within the Lake County Stormwater Management Ordinance which require new developments to utilize stormwater management systems which are designed to maintain predevelopment levels of stormwater discharge for the design storm specified by the Lake County Pollution Control Board or other appropriate governmental agencies, and which consider stormwater management systems on adjacent development to promote efficient land use.

Policy 6C-3.6: Adeuuate Flood Protection. Lake County Land Development Regulations shall include provisions that require stormwater management systems within all development to be designed and installed to provide adequate flood protection for all primary structures and to protect the structural integrity of all roadways.

Policy 6C-3.7: Provide for Stormwater Run-Off. Lake County Land Development Regulations shall require that all new stormwater management systems provide for the safe handling of all stormwater run-off that flows into, across, and is discharged from the site without creating any additional flooding to adjacent property owners.



Policy 6C-3.8: Desicrn Standards. Lake County shall utilize the design standards contained within the Lake County Stormwater Management Ordinance for construction and maintenance requirements of all stormwater retentioddetention systems and ensure compliance with these requirements to prevent degradation of the receiving surface water bodies.

OBJECTIVE 6C-4t PROTECT THE FUNCTIONS OF NATURAL PEATURES: Lake County shall 1) minimize the occurrence of flooding that is a threat to human health or property; 2) identify and prohibit drainage wells 3) improve its ability to manage stormwater so as to minimize the degradation of surface water in order to protect the functions of natural features.

Policy 6C-4-11 Protection of Natural Features throuah the Land Jkveloment Recrulations and the Stormwater Manaaement Ordinance. By 1992, Lake County shall ensure that the stormwater management regulations, contained in the Land Development Regulations, continue to protect natural features by approving only those developments that are consistent with the Lake County Stormwater Management Ordinance.

Policy 6C-4.2: Flood Hazard Area Restrictions. Lake County shall not approve the construction of any proposed road, street, or facility within a designated flood hazard area, unless mitigation measures, as set forth within the Land Development Regulations, are installed by the developer to overcome an identified flood hazard. All mitigation measures installed by the developer must be certified acceptable by the County prior to development. The Lake County Stormwater Management Ordinance shall contain provisions for the use of compensating storage to compensate for the loss of floodwater storage capacity.

Policy 6C-4.3: Best Manaaement Practices. Lake County shall require that Best Management Practices for agriculture, construction and silviculture be employed to protect the function of stormwater management and to minimize contributions of poor quality stormwater run-off to receiving water bodies.

Policy 6C-4.4: Location of RetentiodDetention Areas. Lake County shall require that retentioddetention areas be designed and located so as to not adversely reduce the existing flood storage of the flood plain.

Policy 6C-4.5: Diversion of the First-Flush of Stormwater. The Lake County Land Development Regulations shall include the provisions that are contained within the Lake County Stormwater Management Ordinance which require the diversion of the first flush of stormwater to separate detention or retention facilities for new or redesigned stormwater management systems which use isolated wetlands. Provisions shall also be included within the Land Development Regulations which address the use.of wet detention facilities where it can be demonstrated that such

VI-C-7 December 21. 1990


facilities provide for treatment of stormwater at the adopted level of service.

Policy 6C-4.6: Drainaae and Injection Wells. Consistent with Policy 7-2.11 within the Conservation Element, Lake County shall prohibit the use of drainage and injection wells for the purposes of stormwater management. Existing drainage and injection wells situated within the County shall be filled and/or capped by the owner of the well and/or the County. These drainage and injection wells shall be phased out as soon as practical, in conformance with the Stormwater Management Master Plan.

Policy 6C-4.7: Desianation of Outstandina Lake Countv Waters Proaram. In furtherance of policies within the Conservation Element, Lake County Land Development Regulations shall include provisions, by 1993, for the establishment of an Outstanding Lake County Waters Program which will identify those water bodies which possess exceptional water quality. The Lake County Stormwater Management Master Plan shall include measures to protect those lakes included in the Outstanding Lake County Waters Program. Through the establishment of the Outstanding Lake County Waters Program, lakes, for which stormwater is determined to be a major water quality problem, shall be identified and corrective measures shall be undertaken as part of the Stormwater Management Master Plan.


APPENDIX B

APPENDIX B

STORMWATER F A C I L I T Y INVENTORY BY SUB-BASIN

BAS I N

O k l a w a h a R i v e r

SUB-BASIN

L a k e W e i r L a k e Y a l e

L a k e G r i f f i n

L a k e E u s t i s

G o l d e n T r i a n g l e

- - - - - F 0 4 0 0 5 F 0 1 0 0 5 F 0 1 0 2 0 F O l O l O F 0 1 0 1 5

GO1050 GO1055 GO1060 GO7005 GO7010 GO9005 6 0 1 0 0 5 GO5005 6 0 5 0 1 0 6 0 5 0 1 5 6 0 5 0 2 0 GO5025 6 0 5 0 3 0

H I 1 0 0 5 H 0 9 0 0 5 H 0 4 0 0 5 H 0 4 0 1 0 H 0 4 0 1 5 H 0 1 0 0 5 H O l O l O H 0 1 0 1 5 H 0 1 0 2 0 H 0 1 0 2 5 H 0 5 0 0 5 H 0 5 0 1 0

I 0 1 0 0 5 I 0 1 0 1 0 I 0 1 0 1 5 I 0 1 0 2 0 I 0 1 0 2 5 I 0 1 0 3 0 I 0 1 0 3 5 I 0 2 0 0 5 I 0 5 0 0 5 I 0 5 0 1 0 - - - - - - - - -

F A C I L I T Y DESCRIPTION

- - - - - S I X ~ ' CBC 3 6 " RCP 4 8 " CMP 5 4 " CMPA 3 6 " RCP

4 8 " RCP 5 ' x 5 ' CBC 4 8 " RCP 4 ' x 4 ' CBC 4 ' x 4 ' CBC 2 - 4 8 ' ' RCP 4 ' X 6 ' CBC 3 6 " R C P 4 2 " RCP 4 2 " RCP 4 8 " RCP 3 6 " RCP 4 2 " RCP

3 6 " RCP 3 6 " CMP 3 6 " RCP 4 8 " RCP 8 ' x S ' CBC 3 6 " RCP 4 ' x 2 ' CBC 1 0 a x 3 ' C B C 3 6 " RCP 3 6 " RCP 2 - 4 8 " RCP 4 8 " RCP

3 6 " C I P 3 6 " C I P 3 ' x 3 ' CBC 3 6 " CMP 3 6 " CMP 3 6 " CMP 3 6 " CMP 3 6 " CMP 3 6 " CMP 3 - 3 6 " RCP - - - - - - - - - - - - - - - -

MAINTENANCE E N T I T Y

- - --- C o u n t y C o u n t y C i t y C o u n t y C i t y

FDOT FDOT FDOT FDOT FDOT C o u n t y C o u n t y FDOT FDOT C o u n t y F 0 0 T FDOT FDOT

C o u n t y FDOT C i t y C i t y C o u n t y C o u n t y F 0 0 T FDOT C o u n t y C o u n t y C o u n t y C o u n t y

C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y FDOT F 0 0 T

, - - - - - - - - - - - -

APPENDIX B ( c o n t i n u e d )

STORMWATER F A C I L I T Y INVENTORY BY SUB-BASI N


FOOT C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y

C o u n t y C o u n t y FOOT FDOT C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y

C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y FOOT FOOT C o u n t y C i t y C i t y FOOT C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y FOOT FOOT C o u n t y C o u n t y C o u n t y

- - - - - - - - - - - - -


2 - 8 ' x 8 ' CBC 3 6 " CMP 4 8 " RCP 7 I x 3 ' CBC 3 - 3 6 " RCP 4 8 " RCP

8 ' x 4 ' CBC 3 6 " CMPA 4 I x 3 ' CBC 8 ' x 4 ' CBC 7 ' x 4 ' CBC 6 ' x 3 ' CBC 5 ' x 2 ' CBC 8 I x 6 ' CBC 2 - 3 6 " RCP

2 - 3 6 " RCP 4 2 " RCP 4 2 " CMP 2 - 4 8 " RCP 3 6 " RCP 3 6 " C I P 3 6 " RCP 4 8 " RCP 3 6 " RCP 4 2 " RCP 8 I x 8 ' CBC 4 ' x 4 ' CBC 4 6 " RCP 3 6 " RCP 3 6 " CMP 3 6 " CMP 3 6 " RCP 4 8 " CMP 6 ' x 4 ' CBC 6 I x 4 ' CBC 3 6 " CMP 1 O 1 x 4 * CBC 4 8 " CMP 3 6 " C I P 6 ' x 4 ' CBC 4 ' x 4 ' CBC 3 6 " CMP 2 - 4 8 " CMP 4 8 " CMP

- - - - - - - - - - - - - - - - -

I D

I 0 4 0 0 5 I 0 4 0 1 0 I 0 9 0 0 5 I 0 9 0 1 0 I 0 9 0 1 5 I 0 9 0 2 0

5 0 1 0 1 5 5 0 1 0 2 0 5 0 7 0 0 5 5 0 7 0 1 0 5 0 9 0 0 5 5 1 2 0 0 5 5 1 2 0 1 0 5 0 1 0 0 5 5 0 1 0 1 0

K 2 4 0 0 5 K 1 7 0 0 5 K O 1 0 1 0 KO1065 K O 1 0 7 0 KO1075 K O 1 0 8 0 KO1085 K O 1 0 9 0 KO1095 K O 1 0 5 0 KO4005 KO40 1 0 KO1055 K O 1 0 6 0 KO1005 KO9005 KO1020 K 1 0 0 0 5 K l O O l O K 1 1 0 0 5 K l l O l O K 1 0 0 1 5 K 1 1 0 2 0 K 1 1 0 2 5 K 1 1 0 3 0 K 1 4 0 0 5 K 1 6 0 0 5 K 2 0 0 0 5

- - - - - - - - -

BAS I N

O k l a w a h a R i v e r ( C o n t i n u e d )

_------o---------

SUB-BASIN

G o l d e n T r i a n g l e ( C o n t i n u e d

L a k e A p o p k a

L a k e H a r r i s

. . . . . . . . . . . . . . . . . . . .



BAS IN


- - - - - - - - - - - - - - - - -

SUB-BASIN

P a l a t 1 a k a h a

81 a c k w a t e r C r e e k


. . . . . . . . . . . . . . . . . . . .


4 - 4 8 " CMP 2 - 3 6 " RCP 5 ' x 3 ' CBC 3 6 " RCP 6 0 " CMP 2 - 3 6 " CMP 4 I x 4 ' CBC 3 ' x 3 ' CBC 2 - 6 ' x 3 ' CBC 9 ' x 5 ' CBC 9 ' x 3 ' CBC 2 4 " RCP 2 - 6 I x 4 ' CBC 3 6 " D I P 3 - 6 0 ' ' CMP 2 - 4 8 " RCP 2 - 4 8 " RCP 4 8 " CMP 4 8 " CMP 4 8 " CMP 4 8 " CMP 4 8 " CMP

2 - 3 6 " RCP 3 6 " RCP 3 6 " RCP 4 8 " RCP 4 5 " RCP 4 8 " RCP 4 8 " RCP 3 6 " RCP 4 8 " RCP 2 - 4 2 " RCP 3 6 " RCP 2 - 3 6 " RCP 3 6 " RCP 3 6 " CMP 3 6 " RCP 4 8 " CMP

MAINTENANCE ENTITY

C o u n t y FOOT FOOT C o u n t y C o u n t y C o u n t y FOOT C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y LCWA LCWA LCWA LCWA

C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y

B A S I N

S t . J o h n s R i v e r

W i t h 1 a c o o c h e e R i v e r

APPENDIX B ( c o n t i n u e d 1


SUB-BASIN

A1 e x a n d e r S p r i n g s

L a d y L a k e

L o g g y Pond Swamp

SE F r u i t l a n d P a r k

G r o v e l a n d - M a s c o t t e

A 1 0 0 0 5 A 0 4 0 0 5 A 0 8 0 0 5 A 0 8 0 1 0 A 1 2 0 0 5 A1 2 0 1 0 A 1 2 0 1 5 A 1 2 0 2 0 A l O O l O A 1 0 0 1 5 A 1 5 0 0 5 A 0 1 0 0 5

- - - NO3005 NO7005 N 1 0 0 0 5 N l O O l O N 1 1 0 0 5 N l l O l O N 1 2 0 0 5 N 1 2 0 1 0 N 1 3 0 0 5 N 1 5 0 0 5 N 1 7 0 0 5 NO6005 NO6010

- - - P 1 0 0 0 5 P O 9 0 0 5 0 1 2 0 0 5 PO7005 P O 8 0 0 5 P l O O l O P 1 0 0 1 5 P 1 2 0 1 0 P 1 2 0 1 5 P I 3 0 0 5 P 1 3 0 1 0 P 1 4 0 0 5

- - - - - - - -


2 - 4 8 ' ' CMP 4 2 " RCP 4 2 " RCP 3 6 " RCP 2 - 3 6 " RCP 4 2 " RCP 4 8 " CMP 3 6 " RCP 4 8 " CMP 4 8 " CMP 2 - 4 2 " CMP 3 6 " RCP

3 6 " CMP 2 - 6 0 " CMP 4 2 " CMPA 3 6 " CMP 7 - 6 0 " CMP 3 6 ' ' CMP 3 - 4 8 ' ' CMP 4 - 4 8 " CMP 4 8 " CMP 2 - 3 O 8 ' x 4 8 " ECP 3 6 " C I P 3 6 " D I P 3 6 " RCP

3 - 4 8 ' ' RCP 3 6 " RCP 2 - 3 6 " CMP 3 6 " CMP 3 - 4 8 " CMP 4 8 " RCP 2 - 6 0 ' ' RCP 2 - 5 4 " RCP 2 - 4 8 ' ' RCP 2 - 4 8 " CMPA 4 - 4 8 " RCP 4 8 " RCP


C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y FDOT FDOT C o u n t y C o u n t y

I C o u n t y C o u n t y , C o u n t y C o u n t y C o u n t y C o u n t y

1 C o u n t y C o u n t y C o u n t y C o u n t y C o u n t y

I C o u n t y / C o u n t y

C o u n t y C o u n t y C o u n t y C o u n t y 1 C o u n t y

, C o u n t y C o u n t y FOOT C o u n t y C o u n t y FOOT

- - - - - - - - - - - - - I F O O T



-

BAS I N

W i t h 1 a c o o c h e e R i v e r ( C o n t i n u e d 1

K i s s i m m e e R i v e r

SUB-BASIN

L a k e Okahumpka

R e e d Hammock Pond

T r o u t L a k e

I I I

I D

9 0 3 0 0 5 9 0 3 0 1 0 9 0 3 0 1 5 9 0 3 0 2 0 9 0 1 0 0 5

--- ---

F A C I L I T Y O E S C R I P T I O N

1 1 8 x 7 . 5 ' CMPA 6 0 " RCP 4 2 " RCP g 8 X 3 * CBC 2 - 3 6 " RCP

----- -----


C o u n t y C o u n t y C o u n t y C o u n t y FDOT

--- - - -

APPENDIX B

LAND USE BY SUB-BASIN

BASIN SUB-BASIN

Oklawaha River Lake Weir

Lake Yale

Lake Griffin

Lake Eustis

Golden Triangle

Lake Apopka

Lake Harris

Palatlakaha

LAND USE PERCENTAGES BY CDM TYPE 1 2 3 4 5 6 7 8 9 10 - - - - - - - - - - 1 7 3 5 1 5 1 1 5 4 3 0 3 7

1 5 3 6 3 5 3 1 2 0 1 3 2 4

1 2 2 9 6 4 4 2 3 0 1 5 2 6

9 2 3 5 4 8 1 4 0 1 0 3 6

7 2 2 7 4 1 0 1 5 0 7 3 6

1 0 4 9 8 3 2 0 3 0 9 1 6

7 3 5 5 3 4 1 3 0 1 6 2 6

6 4 3 8 2 1 0 2 0 2 4 1 4

Wekiva River Blackwater Creek 23 30 11 5 3 0 1 0 19 7

Wekiva River 1 3 3 9 2 1 1 0 4 0 1 0 9 3

St. Johns River AlexanderSprings 48 8 4 1 1 1 1 0 26 9

Withlacoochee River ~ a d y Lake 1 7 3 5 1 5 1 1 6 4 4 0 2 6

Loggy pond Swamp 4 2 2 1 9 0 0 0 0 0 5 4 1

SEFruitlandPark 11 26 7 6 9 2 8 0 21 10

Groveland-Mascotte 10 42 9 2 1 0 1 0 27 7

Lake Okahumpka 10 24 6 5 10 2 8 0 25 10

ReedHammockPond 8 41 8 2 1 0 2 0 31 6

Kissimmee River Trout Lake 5 5 2 5 0 0 0 1 0 2 1 1 6

APPENDIX B

SOILS BY SUB-BASIN

BASIN SUB-BASIN

Oklawaha Lake Weir Lake Yale Lake Griffin Lake Eustis Golden Triangle Lake Apopka Lake Harris Palatlakaha

Wekiva Blackwater Creek Wekiva River

St. Johns River Alexander Springs

Withlacoochee Lady Lake Loggy Pond Swamp SE Fruitland Park Groveland-Mascotte Lake Okahumpka Reed Hammock Pond

Kissimmee Trout Lake

SUB-BASIN AREA (AC

8 BY SOIL TYPE A B C D - - - -

APPENDIX C

(Provided to Lake County under separate cover)

MAY 1991 - University of South Florida County... · 2010-11-29 · 3.1.4 Kissimmee River 3.1.5 St. Johns River Hydrologic Boundaries ... o There are a few drainage complaints throughout

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