Agenda 02/09/2021 Item #11D (SFWMD's BCB Boundary Delineation study)02/09/2021
EXECUTIVE SUMMARY
Recommendation to accept a presentation on the Big Cypress Basin (BCB) Boundary
Delineation study conducted by the South Florida Water Management District (District)
and recently submitted to the Governor and legislative leadership as directed in the 2020
General Appropriations Act.
______________________________________________________________________________
OBJECTIVE: To hear a presentation on the Big Cypress Basin (BCB) Boundary Delineation
study conducted by the South Florida Water Management District (District) and recently
submitted to the Governor and legislative leadership as directed in the 2020 General
Appropriations Act. Senate Bill 406 and House Bill 209, which propose expansion of the BCB
administrative boundary using this study as a scientific basis, are currently pending committee
consideration in Tallahassee.
CONSIDERATION: Lee County, the City of Bonita Springs, and the Village of Estero have
petitioned the District to evaluate an amendment of basin administrative boundaries to consider
moving areas of Lee County to the BCB. The impacts on the BCB, both in governance and
operations, of an expansion of its boundaries have not been quantified.
In their 2020 General Appropriations Act, the Legislature included language directing the
District to “conduct a study to recommend the most appropriate geographic boundaries of the
Big Cypress Basin” and to submit the report to the Governor and the leadership of the
Legislature by February 1, 2021. On November 18, 2020, the BCB Board was presented a draft
report of the scientific study determining the hydrologic boundaries of the Big Cypress Swamp
sub-basin.
On December 30, 2020, Lee County State Senator, Ray Rodrigues, filed SB 406, setting the
membership of the BCB governing board to five appointed members, expanding the basin
boundary to the scientific boundary (excluding any county with less than 50 percent of their
jurisdiction within the scientific boundary), and allocating ad valorem tax collections to projects
within the county of origin. On January 11, 2021, Representative Adam Botana filed an identical
bill with the Florida House of Representatives.
At the January 12, 2021, Board meeting, staff conducted an overview of the technical
deficiencies in the proposed legislation, including the lack of apportionment between Lee and
Collier counties of the five appointed seats on the Basin board, the methodology of inclusion of
counties to be part of the new administrative boundary, and the restricted use of ad valorem
collected in the respective counties solely for “projects.”
At the January 26, 2021, Board meeting, a motion was adopted directing staff to coordinate a full
hearing on the proposed Basin boundary expansion featuring a presentation on the scientifically
based study submitted by the District to the Legislature.
FISCAL IMPACT: This executive summary has no immediate fiscal impact.
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02/09/2021
GROWTH MANAGEMENT IMPACT: This executive summary has no immediate growth
management impact.
LEGAL CONSIDERATIONS:
RECOMMENDATION: That the Board accept a presentation on the Big Cypress Basin
Boundary Delineation study conducted by the South Florida Water Management District and
recently submitted to the Governor and legislative leadership.
Prepared by: John Mullins
ATTACHMENT(S)
1. The SFWMD transmittal letter of the study to the Governor/Legislative Leadership (PDF)
2. BCB_Boundary_Delineation_Dec2020_FINAL (PDF)
3. BCB_Presentation_CC_Feb2021 (PDF)
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02/09/2021
COLLIER COUNTY
Board of County Commissioners
Item Number: 11.D
Doc ID: 14886
Item Summary: ***This item to be heard no sooner than 1:00 p.m.*** Recommendation to
accept a presentation on the Big Cypress Basin (BCB) Boundary Delineation study conducted by the
South Florida Water Management District (District) and recently submitted to the Governor and
legislative leadership as directed in the 2020 General Appropriations Act. (John Mullins, Government
Affairs Manager, County Manager's Office)
Meeting Date: 02/09/2021
Prepared by:
Title: Director - Operations Support – Administrative Services Department
Name: Michael Cox
02/01/2021 9:53 AM
Submitted by:
Title: Executive Secretary to County Manager – County Manager's Office
Name: MaryJo Brock
02/01/2021 9:53 AM
Approved By:
Review:
County Attorney's Office Michael Cox Level 3 County Attorney's Office Review Skipped 02/01/2021 9:59 AM
Office of Management and Budget Michael Cox Level 3 OMB Gatekeeper Review Skipped 02/01/2021 10:00 AM
County Manager's Office Dan Rodriguez Level 4 County Manager Review Completed 02/01/2021 10:57 AM
Board of County Commissioners MaryJo Brock Meeting Pending 02/09/2021 9:00 AM
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The Honorable Ron DeSantis, Governor The Honorable Wilton Simpson, President
State of Florida The Florida Senate
The Capitol 409 The Capitol
400 S. Monroe Street 404 S. Monroe Street Tallahassee, FL 32399-0001 Tallahassee, FL 32399-1100
The Honorable Chris Sprowls, Speaker
Florida House of Representatives
420 The Capitol
402 S. Monroe Street
Tallahassee, FL 32399-1300
January 12, 2021
Subject: Submission of the Watershed Review of the Big Cypress Basin
Dear Governor De Santis, President Simpson, and Speaker Sprowls:
Florida Law, Chapter 2020-111 (House Bill No. 5001) includes language directing the South
Florida Water Management District to conduct a study to recommend the most appropriate
geographic boundaries of the Big Cypress Basin. The proviso language specifically requires the
District to base the study “solely upon the common watershed within the Big Cypress Basin and
must be scientifically supported.” The findings of the study are to be submitted to the Governor,
the President of the Senate and the Speaker of the House of Representatives by
February 1, 2021.
We have completed the study and attached to this letter is a report documenting the approach
and results. The work was completed using a scientific approach that incorporated new
information including topographic data and land use changes. As required, the study was based
on the common hydrologic watershed comprising the Big Cypress Basin, the Big Cypress Swamp
Sub Basin. The resulting map is based solely on the hydrologic basin.
The study has been peer reviewed, presented to local stakeholders, and presented at a public
meeting of the Big Cypress Basin Board. With this submittal we are satisfying the requirement to
deliver the recommended changes to the Governor, the President of the Senate and the Speaker
of the House of Representatives as required by law.
Thank you,
Drew Bartlett Executive Director
DB/ao
Enclosure
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Packet Pg. 260 Attachment: The SFWMD transmittal letter of the study to the Governor/Legislative Leadership (14886 : BCB item)
Big Cypress Basin (BCB)
Boundary Delineation
South Florida Water Management District
Hydrology and Hydraulics Bureau
December 2020
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EXECUTIVE SUMMARY
Regional land areas are conceptually divided into smaller units or watersheds to help with the
management of land and water in those areas, as well as for more convenient legal and political
administration and organization. The process of delineating the boundaries of watersheds can be
done in several ways. A science-based approach to watershed delineation establishes the boundary
lines based on physical laws and environmental features of the landscape. Typically, the main factor
that defines a catchment is the land elevation, which naturally drains rainfall and runoff from higher
areas to lower areas and leads to a single discharge point for each catchment. Examples of other
physical factors considered in a science-based approach include land use, man-made improvements to
drainage features, animal habitats, and subsurface properties of aquifers. A science-based approach is
based on measurements of physical properties and is repeatable and verifiable by independent
observation.
This report documents the study to recommend the most appropriate geographic boundaries of the
Big Cypress Basin as mandated in CHAPTER 2020-111, House Bill No. 5001, which states:
The South Florida Water Management District shall conduct a study to recommend the most
appropriate geographic boundaries of the Big Cypress Basin. The proposed boundaries shall
be based solely upon the common watershed within the Big Cypress Basin and must be
scientifically supported. The completed study and recommendations must be submitted to the
Governor, the President of the Senate, and the Speaker of the House of Representatives by
February 1, 2021.
This report provides a general methodology or approach for conducting a scientifically supported
delineation, then applies the methodology to review watershed boundaries in the Big Cypress Basin
(BCB). In cases where it was determined that a watershed boundary required updating, an analysis
was conducted, and modified boundaries were proposed. This analysis considers historical factors
but is an assessment of the current state of the system.
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TABLE OF CONTENTS
Executive Summary .................................................................................................... 2
Table of Contents ...................................................................................................... 3
List of Figures .......................................................................................................... 4
List of Tables ........................................................................................................... 4
Description of Science-Based Delineation Methodology .......................................................... 5
Step 1: Review current catchment boundaries ................................................................. 5
Step 2: Evaluate the topography .................................................................................. 5
Step 3: Examine aerial photography ............................................................................. 5
Step 4: Review road maps ......................................................................................... 6
Step 5: Conduct a field visit ....................................................................................... 6
Step 6: Review permits ............................................................................................. 6
Step 7: Review soil maps ........................................................................................... 6
Step 8: Review other historical documents ..................................................................... 6
Step 9: Distribute proposed delineation for review ............................................................ 7
BCB Basin Boundary Delineation ..................................................................................... 7
Region A: Iona Drainage District ................................................................................. 11
Region B: Whiskey Creek .......................................................................................... 11
Region C: Old Ft. Myers Well Field .............................................................................. 12
Region D: SR82 corridor ........................................................................................... 13
Region E: Upper Corkscrew ....................................................................................... 14
Region F: Okaloacoochee Slough ................................................................................. 17
Region G: CR846 & CR858 ......................................................................................... 18
Region H: L-28 Gap Boundary .................................................................................... 20
Region I: Coastal Sloughs .......................................................................................... 23
Summary ............................................................................................................... 25
References ............................................................................................................. 26
APPENDIX A ............................................................................................................ 28
Hydrologic Unit Levels ............................................................................................. 28
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LIST OF FIGURES
Figure 1. Hydrologic features of the Big Cypress Basin. Green outline represents the existing Big Cypress
Swamp sub-basin boundary. .......................................................................................... 7
Figure 2. Existing BCS sub-basin in green with internal watersheds and neighboring external watersheds
in orange. ............................................................................................................... 8
Figure 3. Nine areas of the Big Cypress Swamp sub-basin examined in depth, with the existing boundaries
in green and proposed revised boundaries in red. See Table 1 for description. ............................ 10
Figure 4. Iona Drainage District map, with the existing boundary in green and proposed revised boundary
in red. .................................................................................................................. 11
Figure 5. Existing Ft. Myers sub-watershed boundary in green with the proposed revised boundaries in
red for both Whiskey Creek and the Old Ft. Myers Wellfield. .................................................. 12
Figure 6. Topography map of the Lehigh Ridge in the SR82 corridor. ......................................... 13
Figure 7. Sub-basin boundary in the SR82 corridor, there is no proposed change to the boundary in this
region. .................................................................................................................. 14
Figure 8. Topography map showing the high elevation of the Immokalee Rise and the Corkscrew Swamp
to the west. ........................................................................................................... 15
Figure 9. Upper Corkscrew headwaters region, showing existing sub-basin boundary in green and proposed
revisions in red. CPI Groves, Turner Groves, and Cow Slough WCD have developed water management
systems in the area that define the drainage flow patterns (Q). .............................................. 16
Figure 10. Topography map of the Okaloacoochee Slough. ..................................................... 17
Figure 11. Map of Okaloacoochee Slough, with the existing boundary in green and proposed revised
boundary in red. ...................................................................................................... 18
Figure 12. The north side of the intersection of CR858 and CR846, with the existing boundary in green
and proposed revised boundary in red. ............................................................................ 19
Figure 13. The region south of the intersection of CR858 and CR846, with the existing boundary in green
and proposed revised boundary in red. ............................................................................ 20
Figure 14. Upper end of L-28 Gap Boundary proposed revisions with the existing boundary in green and
proposed revised boundary in red. ................................................................................. 21
Figure 15. Middle portion of L-28 Gap Boundary proposed revisions with the existing boundary in green
and proposed revised boundary in red. ............................................................................ 22
Figure 16. Lower end of L-28 Gap Boundary proposed revisions with the existing boundary in green and
proposed revised boundary in red. ................................................................................. 22
Figure 17. Coastal sloughs with the existing boundary in green and proposed revised boundary in red. 23
Figure 18. BCS and coastal sloughs with the existing boundary in blue and proposed revised boundary in
red. ..................................................................................................................... 24
Figure 19. Full set of proposed revisions to existing Big Cypress Basin sub-basin boundary delineation.
The green line represents the existing BCS sub-basin boundary, and the red line represents the proposed
revisions to the boundary. ........................................................................................... 25
LIST OF TABLES
Table 1. Description of BCS study regions .......................................................................... 9
Table A-1. Six levels of hydrologic units........................................................................... 28
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DESCRIPTION OF SCIENCE-BASED DELINEATION
METHODOLOGY
The process to evaluate watershed boundaries requires consideration of several sources of information
relevant to the stated purpose of the boundary determination. These sources may range from current
scientific data stored in databases to soil surveys to land use permits to historical maps and land
surveys. The following steps outline a prioritized methodology for conducting a science-based
delineation with numerous sources of information. As a writing convention, the remainder of this
analysis defines a catchment as any land area that drains through a single location, and the hierarchy
from largest area to smallest area is consistent with the naming convention established by the USGS
(Appendix A) and adopted by the South Florida Water Management District (SFWMD or District)
ArcHydro Enhanced Database (AHED) (SFWMD, 2020c), where basin > sub-basin > watershed >
sub-watershed. Earlier drainage studies or projects in other areas of the District may follow other
conventions.
Step 1: Review current catchment boundaries
In a Geographic Information System (GIS) setting, overlay existing drainage boundary maps and
coverages. Areas where multiple existing boundary lines are identical will provide insight into the local
features of the landscape, while areas where boundary lines differ will reveal areas where boundaries
may not be clear-cut to define, where changes in drainage have occurred over time, where better data
has become available, or possibly where non-science based methodologies were used. Additionally,
differences in the boundary lines may indicate subtle changes in the landscape and shallow geology
that affect surface hydrology. Newer maps are likely to include better data resolution and the changes
in hydrography that have resulted from more-recent development, and therefore can confirm the
continuation of previous boundaries or reveal where new boundaries have formed.
Step 2: Evaluate the topography
In GIS use the best available digital elevation data to represent the topography of the landscape.
Complete an assessment of the topography by comparing and contrasting high and low elevations
with the catchment boundaries identified in Step 1. Up-to-date topographic data can provide valuable
insight in determining which catchment boundaries need realignment. In many cases, remote sensing
technology for determining topography with high resolution at a regional scale, such as Light
Detection and Ranging (LIDAR) (Lukas & Stoker, 2016), has resulted in more extensive and
comprehensive data for analyses.
Step 3: Examine aerial photography
Conduct a survey on available aerial photography to identify current and historical land use, natural
drainage features, and drainage characteristics modified through development. Current satellite
imagery typically gives the most up-to-date aerial perspective, and older satellite imagery and historical
flyover photographs should be reviewed when available. Older photographs in particular are useful
for documenting changes over time.
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Step 4: Review road maps
Roads are typically constructed on higher land surfaces, and therefore are commonly used as
catchment boundaries. However, roads also may have a variety of drainage features such as bridges,
culverts, and ditches that may affect drainage pathways, so a careful review of runoff routing and
pathways as a result of such drainage features must be conducted.
Step 5: Conduct a field visit
If possible, visit the location to conduct on-site reconnaissance to help confirm drainage patterns and
features. Site visits, especially when conducted shortly after a large rainfall event, provide visual
confirmation of runoff patterns in the landscape that help guide the establishment of the boundary
lines. Photographs and video taken during a site visit, especially if aerial images are available via a
helicopter or drone, are priceless records of the state of the system that can be used in the
establishment of the boundaries and for planning of current and future projects.
Step 6: Review permits
Conduct a review of any regulatory action or authorized permits that may alter or describe drainage
patterns in a catchment, especially any permits related to the properties along the perimeter of a
catchment and the relation to neighboring catchments. For example, SFWMD Environmental
Resource Permits (ERPs) (SFWMD, 2020a) provide useful information for determining local
hydrology. In the conceptual project documents of the ERPs, project engineers delineate pre- and
post-project drainage patterns which may identify drainage patterns where the relief is too flat and
ambiguous to resolve using other information. The approved permits describe any resulting changes
to surface hydrology and as-built documents provide specific locations and dimensions of surface
water control features.
Step 7: Review soil maps
If available, soil maps may be a useful reference to supplement the items above. The soils reflect an
integration of landscape, land use, vegetation, and surface and subsurface hydrology. The published
soils maps vary in detail and can be largely based on current land cover and landscape features.
However, the soil series boundaries are secondary and confirmatory and should not contradict or
overrule primary surficial factors such as topography in defining the catchment boundary maps.
Step 8: Review other historical documents
Search for and review any other historical documents available. Examples could be old county road
maps and USGS quad sheets, which may have large-scale features that are not present on current
maps. The large-scale landscape features may be indicative of native drainage patterns or drainage
patterns that were present prior to more recent development. Development frequently enhanced or
accommodated the native features, while the old roads frequently honored those features due to the
cost incurred in building roads in difficult locations.
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Step 9: Distribute proposed delineation for review
Distribute draft delineation to subject matter experts for review of areas such as water supply planning,
permitting (ERP, Water Supply, etc.), and legal and policy-related matters.
BCB BASIN BOUNDARY DELINEATION
The objective of this study is to “recommend the most appropriate geographic boundaries of the Big
Cypress Basin”. The starting point for this assessment is the boundaries of the Big Cypress Swamp
(BCS) sub-basin (USGS HUC number 03090204) shown in Figure 1. This sub-basin is an aggregation
of all AHED watersheds south of the Caloosahatchee Estuary that discharge to the Gulf of Mexico.
Figure 1. Hydrologic features of the Big Cypress Basin. Green outline represents the existing Big Cypress Swamp
sub-basin boundary.
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The watersheds within the BCS sub-basin are shown in Figure 2, along with the neighboring
watersheds outside the BCS sub-basin. The sub-basin was developed by SFWMD, in coordination
with USDA & USGS while developing the AHED geodatabase (SFWMD, 2004).
Figure 2. Existing BCS sub-basin in green with internal watersheds and neighboring external watersheds in orange.
There are several significant hydrologic features of the Big Cypress Swamp sub-basin (SFWMD, 2017)
(Figure 1). The first is the Corkscrew marsh in northern Collier County that drains to the southwest
along the southern border of Lee County and drains to the west coast. The Corkscrew marsh includes
the Flint Pen Strand and Bird Rookery Swamp, and discharges to the Gulf of Mexico through the
Cocohatchee River, Imperial River, Estero River to the west and the Faka Union Canal system to the
south. The western inflows, along with Six-Mile Cypress and Hendry/Mullock sloughs, are a
significant portion of the inflows to Estero Bay. The second feature is the Big Cypress Swamp in
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central Collier County, a large rain-driven cypress swamp and wet prairie that drains to the south
through a group of shallow sloughs to the coastal estuaries of the Ten Thousand Islands. Additionally,
there are several canal systems including the Cocohatchee, Henderson Creek, Golden Gate, and Faka
Union canal systems. These canals drain to the west and to the coastal slough and bays to the south.
To the east of these canals is the Fakahatchee Strand, which receives runoff from the Okaloacoochee
Slough and drains into the same coastal estuary and bay complex. Finally, the Big Cypress National
Preserve (BCNP) is in eastern and southeastern Collier County and makes up the southern portion of
the BCS sub-basin1. Like the BCS, the BCNP is a large rain-driven swamp and drains to the southwest
through many sloughs to the Gulf of Mexico.
The principal physically-based boundary for the BCB is defined by the AHED (BCS) sub-basin
boundary. This sub-basin defines the catchment that drains to the Lower West Coast. The boundary
of the BCS sub-basin is bounded on the north by the Caloosahatchee sub-basin, which includes the
Caloosahatchee river and estuary, and on the east by the Everglades sub-basin. The current sub-basin
boundaries provide a starting point for the evaluation of the catchment boundaries for the BCS sub-
basin performed as part this study. In addition to AHED, other sources of information considered
include the Southwest Florida Feasibility Study (USACE, 2015) – BEM (SWFFS-BEM) sub-
watershed boundaries (BEM, 2004), particularly the Hendry/Mullock sub-watershed. The SWFFS
sub-watersheds are a verified update from the Lee County stormwater master plan boundaries (JEI,
CDM, HMA & WDBA, 1991a,b) and the Johnson Engineering, Inc. boundaries (JEI et al, 1998).
Additionally, the Florida Department of Environmental Protection (FDEP) more-recently developed
a set of boundaries for the Caloosahatchee River and Caloosahatchee Estuary which were also
considered in this analysis (FDEP, 2012).
A science-based review of the existing sub-basin boundaries was conducted and is broken down into
nine key regions starting in the northwest portion of the BCS sub-basin and moving clockwise. It was
determined that eight of the nine regions need revision. The nine areas considered are described in
Table 1 and are shown in Figure 3.
Table 1. Description of BCS study regions
Region ID (Fig. 3) Description
Boundary
Revision
Proposed?
Watershed
inside BCS Watershed outside BCS
A Iona Drainage District Y Estero Bay Tidal South
B Whiskey Creek Y Estero Bay Tidal South
C Old Ft. Myers Well Field Y Estero Bay Tidal South
D SR82 Corridor N Estero Bay Tidal South
E Upper Corkscrew Y Trafford West Caloosahatchee
F Okaloacoochee Slough Y Okaloacoochee East Caloosahatchee
& C139
G CR846 & CR858 Y Okaloacoochee &
East Collier
Feeder Canal & L-28
Gap
H L-28 Gap Boundary Y East Collier L-28 Gap
I Coastal Sloughs Y East Collier &
Chatam Turner
ENP & Lostmans
1 Note that the “BCS” is a land area in Collier County and the “BCS sub-basin” is a distinct sub-basin in AHED.
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Figure 3. Nine areas of the Big Cypress Swamp sub-basin examined in depth, with the existing boundaries in green
and proposed revised boundaries in red. See Table 1 for description.
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Region A: Iona Drainage District
The sub-watershed boundary in south Ft. Myers is defined by the Iona Drainage District (IDD) canal
system. The IDD canals were constructed in the 1920s and are the basis for the current canal system.
In this low-gradient landscape, the catchment divides are determined by neighborhood drainage
ditches and roads between the IDD canals. The current BCS sub-basin boundary follows the original
IDD divides. Approximately half of the canals drain to the Caloosahatchee River (i.e. outside BCS)
and the remaining canals drain to Hendry Creek (i.e. inside BCS). At Deep Lagoon, the drainage has
been improved by several mosquito control canals and the drainage south is blocked by an old roadbed
south of Summerlin Rd. The revised boundary follows San Carlos Blvd., as the water in San Carlos
Bay is generally more representative of discharges from the Caloosahatchee River than it is of the
water in Estero Bay. The proposed revised boundary is shown in Figure 4.
Figure 4. Iona Drainage District map, with the existing boundary in green and proposed revised boundary in red.
Region B: Whiskey Creek
The Fort Myers sub-watershed is modified to better reflect the drainage pattern in the Lee County
Whiskey Creek watershed Following the drainage description from the Lee County surface water
watersheds (AHED sub-watersheds), a southward shift to the boundary to better reflect the drainage
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of the IDD H-9 canal which drains to Whiskey Creek and the Caloosahatchee Estuary is
recommended as part of this study. The proposed revised boundary is shown in Figure 5.
Figure 5. Existing Ft. Myers sub-watershed boundary in green with the proposed revised boundaries in red for
both Whiskey Creek and the Old Ft. Myers Wellfield.
Region C: Old Ft. Myers Well Field
The basin boundary has been modified due to the development of the old Ft. Myers municipal well
field and the Hanson Street improvements. The spray field has limited drainage as it was designed to
receive and distribute water pumped from the Caloosahatchee River. The spray field has been
decommissioned and is being developed into other land uses. Hanson Street is being improved to
facilitate the improvements. The drainage on the site has been modified so that the runoff from the
golf course and adjacent land drains under Hanson Street and in ditches that drain into 10-mile canal
and Estero Bay. The proposed revised boundary includes a slight northward shift and is shown in
Figure 5.
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Region D: SR82 corridor
The SR82 road provides the basin boundary (Figures 6 and 7). Historically a ridge through Lehigh
Acres defined the drainage divide between the Orange River and Upper Estero Bay landscapes. SR82
was placed on the southern shoulder of the ridge, and the East County Water Control District
(ECWCD) drainage network was constructed to direct the surface drainage to the Orange River and
Hickey Creek. Although there are small projects designed to direct more flow south, SR82 remains
the BCS sub-basin boundary and no changes to the boundary lines are proposed as part of this study.
Figure 6. Topography map of the Lehigh Ridge in the SR82 corridor.
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Figure 7. Sub-basin boundary in the SR82 corridor, there is no proposed change to the boundary in this region.
Region E: Upper Corkscrew
The land north of SR82 east of Lee County is the headwaters of the Corkscrew watershed. This land
is west of the Immokalee Rise (Figure 8). The land contains several citrus groves with well-developed
water management systems that define the drainage boundaries. The CPI grove (ERP: 26-00159-S)
is constructed to drain north to the Caloosahatchee River. The Turner Groves water management
system (ERP: 11-00262-S) drains to Corkscrew Swamp. There are two additional properties between
Turner Groves and CPI, and they drain to Corkscrew swamp.
The Cow Slough Water Control district (CSWCD, ERP: 26-00324-S) provides drainage for several
landowners whose land may have drained naturally to Corkscrew on the west or the Okaloacoochee
Slough on the east. The runoff from the ranch land and citrus groves in the CSWCD drains into
canals that flow via the Townsend Canal to the Caloosahatchee River. The CSWCD borders on the
Turner Groves to the west and SR 29 on the east. The proposed revised boundary is included with
these permitted areas in Figure 9.
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Figure 8. Topography map showing the high elevation of the Immokalee Rise and the Corkscrew Swamp to the
west.
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Figure 9. Upper Corkscrew headwaters region, showing existing sub-basin boundary in green and proposed
revisions in red. CPI Groves, Turner Groves, and Cow Slough WCD have developed water
management systems in the area that define the drainage flow patterns (Q).
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Region F: Okaloacoochee Slough
The Okaloacoochee Slough (OKS) is the predominant natural drainage feature east of the Immokalee
Rise. OKS is a shallow marsh that drains North to the Caloosahatchee River and south to the Gulf
of Mexico via the Fakahatchee. The drainage boundary is defined by the topography and roads. The
west side of the drainage is defined by SR29 going north along the east side of CSWCD until CR830.
The drainage ditch along CR830 captures runoff from the south and discharges to OKS on the east.
Runoff north of CR830 drains to the north into Roberts Canal and north to the Caloosahatchee River,
and a small levee defines the sub-basin divide from CR830 to CR832. CR832 is located along a
moderate ridge approaching the slough from the west side, and a detailed review of the LIDAR shows
that the drainage divide occurs at CR832 (Figure 10).
Figure 10. Topography map of the Okaloacoochee Slough.
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Along the east side of OKS south of CR832, the landscape, topography and natural drainage are
indeterminant. The Alico ranch has constructed all-season roads that appear to provide a drainage
divide. To the south, the Dinner Island property has a ditch system that provided drainage for the
property when it was a ranch. The drainage system included a berm, road and drainage ditch along
the west side of the property that divides the flow between the OKS and the C-139 watershed. The
proposed revised boundary is shown in Figure 11.
Figure 11. Map of Okaloacoochee Slough, with the existing boundary in green and proposed revised boundary in
red.
Region G: CR846 & CR858
In northern Collier County, CR846 leaves the city of Immokalee and runs due east into Hendry County
before turning north into central Hendry County (Figure 12). CR858 runs north to south and forms
the boundary between Collier and Hendry Counties. South of CR846 in this region, the BCS sub-
basin boundary separates the OKS from the Feeder Canal and L-28 Gap watersheds (Figure 13).
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Figure 12. The north side of the intersection of CR858 and CR846, with the existing boundary in green and
proposed revised boundary in red.
There are agricultural developments along CR858 that have developed water management systems
that partition drainage either toward OKS to the west or to the east. The discharge that flows to the
east may contribute to runoff in the Feeder basin or flow south toward the L-28 Gap and Mullet
slough. The fine resolution LIDAR indicates that the land slopes from higher ridges in the northwest
downward to the southeast, and the runoff is therefore expected to flow toward the southeast.
Agricultural land along the western edge of the Feeder sub-watershed directs the water south. A
private road extending from Wainwright Drive to Winegate Mill Road acts as a water control feature.
There are two significant ditches flowing under the road. Surface runoff flowing down the eastern
ditch flows into the headwaters of Mullet Slough while the runoff flowing into the western ditch flows
south to a drainage ditch that flows west along Shoults Grade to OKS. The land south of Shoults
grade drains to the west or to the south. A road to the east of Shoults Grade, Ranch Nursery Road
provides a berm that separates runoff that flows south into the East Collier watershed from runoff
that flows into Mullet Slough in the Feeder Canal watershed. At the southeast corner of the agricultural
land the boundary follows a low ridge until it meets an old road. The boundary follows the road south
until it reaches I-75. The proposed revised boundary is shown in Figures 12 and 13.
The boundary follows one of the shallow ridges south from I-75 and turns towards the east and
connects with the L-28 tie-back levee. The boundary through this region is somewhat indeterminant.
The direction of surface flow is determined by season, local water levels and recent burns.
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Figure 13. The region south of the intersection of CR858 and CR846, with the existing boundary in green and
proposed revised boundary in red.
Region H: L-28 Gap Boundary
The L-28 levee provides a boundary between BCS (East Collier watershed) and Everglades Water
Conservation Area 3A (WCA-3A) (Figure 2). Before development, the edge of the Everglades may
have been further east where peat soil occurs. Runoff from Mullet Slough flowed east into the
Everglades and curved back to the west and flowed back into the marsh (WCA3A). With the
construction of the L-28 and L-28 Tieback the marsh is cut off from those flows. Cuts were made in
the L-28 Tieback to facilitate rehydration of the east edge of the swamp. The L-28 Borrow canal is
located on the east side of the levee on the northern half and located on the west side of the levee on
the south half of the L-28. Water from the canal can interact directly with the swamp on the south
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half. At the south end, the L-28 canal intersects with the Tamiami road ditch and the L-29. Most of
the discharge from L-28 goes into L-29 and flows into the Everglades through five culverts. The
proposed revised boundary is shown in Figures 14-16.
Figure 14. Upper end of L-28 Gap Boundary proposed revisions with the existing boundary in green and proposed
revised boundary in red.
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Figure 15. Middle portion of L-28 Gap Boundary proposed revisions with the existing boundary in green and
proposed revised boundary in red.
Figure 16. Lower end of L-28 Gap Boundary proposed revisions with the existing boundary in green and proposed
revised boundary in red.
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Region I: Coastal Sloughs
South of Tamiami Trail the Pinecrest string of hammocks provides a flow divide between Dayhoff
Slough and Lostmans Slough (Figure 17). Pre-development, Dayhoff slough received runoff from
Big Cypress Swamp while Lostmans Slough primarily received runoff from what is now WCA-3A.
This historic connection has been severed by the L-28 canal and runoff from the area now discharges
to the L-29 canal. The runoff from the swamp west of L-28 and east of the Pinecrest hammocks
appears to collect in the Tamiami ditch and flow under Tamiami Trail through two culverts and flows
to the southwest through shallow channels in the wet prairie landscape. The proposed revised
boundary is shown in Figures 17 and 18.
Figure 17. Coastal sloughs with the existing boundary in green and proposed revised boundary in red.
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Figure 18. BCS and coastal sloughs with the existing boundary in blue and proposed revised boundary in red.
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SUMMARY
This report provides a science-based assessment of the Big Cypress Swamp sub-basin boundaries.
The analysis was done considering a wide variety of current and historical information and presents
the most accurate sub-basin boundary delineation based on current conditions. The analysis shows
that some of the previous boundaries are still accurate sub-basin limits, but other regions require
revisions to represent the most current conditions. A comparison of the existing sub-basin boundary
and the proposed revised boundary is shown in Figure 19.
Figure 19. Full set of proposed revisions to existing Big Cypress Basin sub-basin boundary delineation. The green
line represents the existing BCS sub-basin boundary, and the red line represents the proposed
revisions to the boundary.
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REFERENCES
BEM Systems (BEM), 2004. Southwest Florida Feasibility Study Modeling Services subtask 3.6:
Preparing Model Input. Prepared for South Florida Water Management District, Fort Myers,
FL. October, 2004. 40 pp.
Florida Department of Environmental Protection (FDEP), 2012. Caloosahatchee Estuary Basin
Management Action Plan (BMAP). Developed by the Caloosahatchee Estuary Basin Technical
Stakeholders in cooperation with the FDEP, Division of Environmental Assessment and
Restoration, Bureau of Watershed Restoration, Tallahassee, FL. December, 2012. 85pp.
Johnson Engineering, Inc. (JEI), Camp Dresser & McKee Inc. (CDM), Hole, Monete & Assoc.
(HMA), and W. Dexter Bender & Assoc. (WDBA), 1990. Lee County Surface Water
Management Master Plan. Interim Report. Prepared for Lee County Division of Natural
Resources Management, Fort Myers, FL.
Johnson Engineering, Inc. (JEI), Camp Dresser & McKee Inc. (CDM), Hole, Monete & Assoc.
(HMA), and W. Dexter Bender & Assoc. (WDBA), 1991a. Lee County Surface Water
Management Master Plan. Six Mile Report. Prepared for Lee County Division of Natural
Resources Management, Fort Myers, FL.
Johnson Engineering, Inc. (JEI), Camp Dresser & McKee Inc. (CDM), Hole, Monete & Assoc.
(HMA), and W. Dexter Bender & Assoc. (WDBA), 1991b. Lee County Surface Water
Management Master Plan. Ten Watersheds Report. Prepared for Lee County Division of
Natural Resources Management, Fort Myers, FL.
Johnson Engineering, Inc. (JEI), Camp Dresser & McKee Inc. (CDM), Hole, Monete & Assoc.
(HMA), and W. Dexter Bender & Assoc. (WDBA), 1992. Lee County Surface Water
Management Master Plan. Nineteen Watersheds Report. Prepared for Lee County Division of
Natural Resources Management, Fort Myers, FL.
Johnson Engineering, Inc. (JEI), Camp Dresser & McKee Inc. (CDM), Hole, Monete & Assoc.
(HMA), and W. Dexter Bender & Assoc. (WDBA), 1996. Lee County Surface Water
Management Master Plan. Six Watersheds Report. Prepared for Lee County Division of
Natural Resources Management, Fort Myers, FL.
Johnson Engineering, Inc. (JEI), Agnoli, Barber & Brundage, Inc., and Boylan Environmental
Consultants, Inc., 1998. Volume I (Interim) South Lee County Watershed Plan. South Florida
Water Management District, West Palm Beach, FL.
Lukas, Vicki, Stoker, J.M., 2016, 3D Elevation Program—Virtual USA in 3D: U.S. Geological
Survey Fact Sheet 2016–3022, 1 p., http://dx.doi.org/10.3133/fs20163022 .
South Florida Water Management District, 2017. Water Control Operations Atlas: Big Cypress
Basin System, Part 1--Watersheds. H&H Bureau and BCB Service Center, SFWMD, West
Palm Beach, FL. 78 pp, April 20, 2017.
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South Florida Water Management District. 2020a. South Florida Water Management District,
EPermitting Database, 2020. Database updated daily, West Palm Beach, FL, Data accessed
June-July, 2020 at www.sfwmd.gov/epermitting
South Florida Water Management District. 2020b. LIDAR datasets available at SFWMD, accessed
June-July, 2020.
SFWMD_SF_MRG_2016_5Ft elevation
WERP_LiDAR_DTM_20171229
T36448_DEM_ALL -Okaloacoochee Slough
DinnerIsland_2016_5ft
ENPN_2017_1_6ft
MD_2015_5ft
HAED_USGS_2007
South Florida Water Management District 2020c. Geospatial Services ArcHydro Enhanced
Database (AHED), accessed June-July, 2020).
https://geo-sfwmd.hub.arcgis.com/search?q=AHED
US Army Corps of Engineers, 2015. Southwest Florida Comprehensive Watershed Plan: A habitat
quilt tied by threads of water reconnecting a sustainable landscape. Jacksonville District,
Jacksonville, FL. 186pp. October, 2015.
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APPENDIX A
Terminology from USGS that is used in the AHED database (SFWMD, 2020c). This report updates
the boundaries of the Big Cypress Swamp sub-basin (HUC ID 03090204; area = 2850 sq mi.).
Hydrologic Unit Levels
The six different levels of hydrologic units for the United States of America are shown in Table A-1.
More information can be found on the USGS website http://water.usgs.gov/GIS/huc.html .
Table A-1. Six levels of hydrologic units.
Hydrologic Unit Level Name Digits Size Hydrologic Units
1 Region 2 Average: 177,560 square miles 21
2 Sub-region 4 Average: 16,800 square miles 222
3 Basin 6 Average: 10,596 square miles 352
4 Sub-basin 8 Average: 703 square miles 2,149
5 Watershed 10 63-391 square miles (40,000-
250,000 acres) 22,000 (estimate)
6 Sub-watershed 12 16-63 square miles (10,000-
40,000 acres) 160,000 (estimate)
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Big Cypress Basin Boundary Delineation
February 9, 2021
Jeff Iudicello, Ph.D., P.E., Lead Engineer, H&H
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Introduction
➢Florida Chapter 2020-111, House Bill No. 5001:
➢Summary:
▪District to examine BCB watershed boundaries, propose revisions as needed
▪Implement a scientifically supported approach
▪Submit to State authorities in Tallahassee by Feb. 1, 2021
The South Florida Water Management District shall conduct a study to recommend the
most appropriate geographic boundaries of the Big Cypress Basin.The proposed
boundaries shall be based solely upon the common watershed within the Big Cypress
Basin and must be scientifically supported.The completed study and recommendations
must be submitted to the Governor,the President of the Senate,and the Speaker of the
House of Representatives by February 1,2021.
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Science-Based Watershed Delineation
➢Divides regional land areas into smaller units or watersheds based on
physical laws
➢Considers the actual environmental features of a landscape
➢Land elevation is a key factor defining runoff from rainfall
➢Other physical factors:
▪Land use
▪Man-made improvements to drainage features
▪Animal habitats
▪Subsurface properties of aquifers
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Science-Based Watershed Delineation
➢Based on measurements of physical properties
➢Would be repeatable and verifiable by independent observation
➢Considers a variety of sources of information
➢Contrasting approaches may use political or legal factors to establish
boundaries
▪Administrative boundaries (e.g. County lines)
▪Landowner property limits
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Delineation Methodology
➢Step 1: Review current catchment boundaries
▪Use Geographic Information Systems (GIS) to overlay existing boundary maps and
coverages
➢Step 2: Evaluate the topography
▪Use digital elevation data in GIS to compare high/low landscape elevations with
catchment boundaries
➢Step 3: Examine aerial photography
▪Survey old and new satellite imagery, flyover pictures, etc., to assess current and
historical land use, natural drainage features, and man-made drainage modifications
➢Step 4: Review road maps
▪Roads are typically constructed on higher land surfaces but may have bridges, culverts,
and/or ditches that affect drainage
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Delineation Methodology
➢Step 5: Conduct a field visit
▪On-site reconnaissance will help confirm drainage patterns and features
➢Step 6: Review permits
▪Regulatory actions and authorized permits (e.g. ERPs) will describe drainage patterns
and modifications resulting from permitted projects
➢Step 7: Review soil maps
▪A valuable secondary source of info on land use, vegetation, and subsurface hydrology
➢Step 8: Review other historical documents
▪Old county road maps, USGS quad sheets, etc., may provide additional useful info
➢Step 9: Distribute proposed delineation for review
▪Seek additional review from subject matter experts.
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Definition of Terms
➢Definitions from District’s ArcHydro Enhanced Database (AHED)
➢AHED District totals, from largest to smallest:
▪Basin –4
▪Sub-basin –12
•Note: Big Cypress Swamp is a sub-basin
▪Watershed –227
▪Sub-watershed -633
➢Earlier drainage studies or projects in other areas of the District may follow
other definitions
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➢Key sub-basin items:
▪Neighboring sub-basins
▪Natural hydrologic features
▪Natural & man-made waterways
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A.Iona Drainage District
B.Whiskey Creek
C.Old Ft. Myers Wellfield
D.SR82 Corridor
E.Upper Corkscrew Swamp
F.Okaloacoochee Slough
G.CR846 & CR858
H.L-28 Gap Boundary
I.Coastal Sloughs
9
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Products
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Results
➢The proposed map is the final product to address HB No. 5001
➢Developed from District expertise, GIS data, permitting knowledge, etc.
➢Consulted with Ft. Myers Service Center staff and BCNP
➢Reviewed by District Bureaus:
•Water Use, Water Supply
•Applied Science, Water Quality
•Ecosystem Restoration Planning, Everglades & Estuaries Protection
➢Numerous external briefings were held with local stakeholders
➢Was submitted to meet Feb. 1 Legislative deadline
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Thank You.
Questions?
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