Agenda 03/18/2014 PELICAN BAY SERVICES DIVISION
Municipal Service Taxing and Benefit Unit
NOTICE OF PUBLIC MEETING TUESDAY, MARCH 18, 2014
THE CLAM BAY COMMITTEE OF THE PELICAN BAY SERVICES
DIVISION WILL MEET TUESDAY, MARCH 18 AT 1:00 PM AT THE
COMMUNITY CENTER AT PELICAN BAY, 8960 HAMMOCK OAK DR.,
NAPLES, FL.
AGENDA
The agenda includes, but is not limited:
1 . Roll call
2. Agenda Approval
3. Audience comments
4. Approval of February 4 meeting minutes
5. Discussion of Management Plan's goal and objectives
6. Discussion of revisions to Chapters 1-4, appendices and bibliography
7. Suggested timeline for management plan and permit application
8. Possible new reports/activities for FY 2015
9. Draft of article for PB Post
10. Establish meeting dates for April and May
11 . Update on ordinance change for Clam Bay
12. Estimated costs and funding source for permit application and related
work
13. Discussion of when to dredge and dredge template
14. Other
15. Adjourn
ANY PERSON WISHING TO SPEAK ON AN AGENDA ITEM WILL RECEIVE UP TO
ONE (1) MINUTE PER ITEM TO ADDRESS THE BOARD. THE BOARD WILL
SOLICIT PUBLIC COMMENTS ON SUBJECTS NOT ON THIS AGENDA AND ANY
PERSON WISHING TO SPEAK WILL RECEIVE UP TO THREE (3) MINUTES. THE
BOARD ENCOURAGES YOU TO SUBMIT YOUR COMMENTS IN WRITING IN
ADVANCE OF THE MEETING. ANY PERSON WHO DECIDES TO APPEAL A
DECISION OF THIS BOARD WILL NEED A RECORD OF THE PROCEEDING
PERTAINING THERETO, AND THEREFORE MAY NEED TO ENSURE THAT A
VERBATIM RECORD IS MADE, WHICH INCLUDES THE TESTIMONY AND
EVIDENCE UPON WHICH THE APPEAL IS TO BE BASED. IF YOU ARE A PERSON
WITH A DISABILITY WHO NEEDS AN ACCOMMODATION IN ORDER TO
PARTICIPATE IN THIS MEETING YOU ARE ENTITLED TO THE PROVISION OF
CERTAIN ASSISTANCE. PLEASE CONTACT THE PELICAN BAY SERVICES
DIVISION AT (239) 597-1749. VISIT US AT
HTTP://PELICANBAYSERVICESDIVISION.NET.
3/17/2014 1:56:33 PM
CLAM BAY COMMITTEE MEETING MINUTES
PELICAN BAY SERVICES DIVISION
TUESDAY, FEBRUARY 4,2014
The Clam Bay Committee of the Pelican Bay Services Division met on February 4,2014 at
1:00 PM at the Community Center at Pelican Bay located at 8960 Hammock Oak Drive,Naples,
Fl. The following members attended:
Clam Bay Committee
Susan O'Brien, Chairman John Domenie
Joe Chicurel Mike Levy
Tom Cravens
Pelican Bay Services Division Board Scott Streckenbein
Pelican Bay Services Division Staff
Neil Dorrill, Administrator Mary McCaughtry, Operations Analyst
Kyle Lukasz, Operations Manager Lisa Resnick, Recording Secretary
Also Present
Mohamed Dabees, Humiston &Moore Engineers
Tim Hall, Turrell-Hall and Associates
Clam Bay Stakeholders
Marcia Cravens Linda Roth
Mary Johnson Kathy Worley
Diane Lustig
REVISED AGENDA
1 . Roll call
2. Agenda approval
3. Audience comments
4. Approval of January 7 meeting minutes
5. Discussion of engineering-related components of Management Plan
6. Discussion of current condition of Clam Pass
7. Update on Idle speed/No wake signs
7.1 Discuss Kathy Worley's goals
7.2 Update on canoe trail signs
8. Set meeting dates for March 4 & 18
9. Other
10. Adjourn
ROLL CALL
All Committee members were present.
52
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Clam Bay Committee Meeting Minutes
February 4,2014
AGENDA APPROVAL
Mr. Domenie motioned,Mr. Cravens seconded, to approve the agenda as amended
[add items 7.1 and 7.21. The motion carried unanimously.
APPROVAL OF JANUARY 7 MEETING MINUTES
I IMr. Cravens motioned,Mr. Domenie seconded, to approve the January 7 meeting
minutes as presented. The motion carried unanimously.
ENGINEERING-RELATED COMPONENTS OF MANAGEMENT PLAN
The Committee reviewed the Humiston and Moore Engineers annual tidal analysis report
and the Clam Pass six-month post-dredge report briefly, and discussed historical dredging events
that were described in the tidal analysis report and debated how detailed this information should
be in the management plan.
Dr. Mohamed Dabees explained that there is a difference between engineering design
plans in permit versus actual construction. Engineering plans in a permit are generalized;
whereas, construction plans are detailed and based on the actual work to be done.
EXISTING CONDITIONS OF CLAM PASS
Dr. Dabees presented recent aerial photographs and reviewed the existing conditions of
Clam Pass.
DEVELOPMENT OF DESIGN CRITERIA
Dr. Dabees described the ebb shoal as the defense shield that allows a small pass like
Clam Pass to survive weather events, the area of critical concern was Section B or the flood
shoal,where sand could build up and dry out, not the width of the channel. As long as there was
water in the back and in front of the channel, a tide, and a section of water to connect the two
waters,then the channel would"fill-in"to its equilibrium width and conform to whatever size it
needs to be. If the flood shoal were to start to dry up then that would be a warning sign. The ebb
shoal is outside of the dredge template and cannot be controlled; however, it does have a huge
impact on the system.. The flood shoal and channel are big parts of what should be included in
the management plan.
Dr. Dabees emphasized there should not be one red line that once that red line is crossed,
dredging is required, or if the red line is not crossed, dredging is not required, and instead,
recommended a set of several indicators or guidelines. The metrics to use as indicators would be
53
Clam Bay Committee Meeting Minutes
February 4,2014
multi-dimensional, (calculating area and volume, not length or width). The design criteria
development deals with the flow cross-section area,volume of sand within the template, channel
length, and ebb shoal size and shape. When more than one of these areas cross the critical
threshold,this would indicate the health of the system, and when conditions for dredging should
occur. These parts of the design criteria development areas were discussed at length.
Dr. Dabees pointed out that in order to recommend the optimal criteria one year's worth
of post-dredging data from the 2013 dredging event would be necessary;however,there is not
yet sufficient data to use as the basis for a recommendation.
Mr. Hall clarified that at this time, Dr. Dabees could prepare the range of metrics, but not
the targets, for the next meeting.
UPDATE ON IDLE SPEED/NO WAKE SIGNS
Mr. Cravens motioned,Mr. Domenie seconded, that the Committee recommend to the
full board to direct Kyle and Tim to come back with an idle speed/no wake sign
replacement plan and bring to the full board at the March meeting. The motion
carried unanimously.
UPDATE CANOE TRAIL SIGNS
Mr. Lukasz reported that seven signs/pilings would be replaced.
SET MEETING DATES FOR MARCH 4 AND 18
The Committee set meeting dates for March 4 and 18.
MISCELLANEOUS
The Committee discussed briefly having Barry Williams, Director of County Parks and
Recreation, to give a presentation regarding Clam Pass Park improvements.
Mr. Dorrill received a complaint regarding shells in the sand at Clam Pass and he
explained that the Services Division is not involved in ongoing mechanical grooming of the
beach. The complainant also mentioned the escarpment is a safety hazard and was told that it
was being monitored.
ADJOURN
Mr. Cravens motioned,Mr. Domenie seconded to adjourn. The motion carried I
unanimously.
Susan O'Brien, Chairman 3/17/2014 11:44:06 AM
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TABLE OF CONTENTS
1.0 Introduction
Purpose of the Clam Bay NRPA Management Plan.
Development of the Clam Bay NRPA Management Plan
Role of Pelican Bay Services Division
2.0 Overview of the Clam Bay NRPA
Natural history
Historical Overview
Mangrove Die-off and Restoration
Time line of important events within the Clam Bay system
Time line specific to establishment of the Clam Bay NRPA
3.0 Resource Descriptions
Soils
Topography
Climate
Natural Communities
Exotic Species
Listed Species
Other Wildlife Species
Hydrology
Water Quality
Archaeological Resources
Inlet Dynamics
Recreational Use
4.0 Authorized Construction Activities
List of permits and work undertaken to date
5.0 Management Goal and Objectives
Management action/work required,performance criteria and monitoring, responsible
entities,timeframe
1. Maintain and protect the native floral and faunal communities within the Clam Bay
NRPA
2. Protect archaeological sites within the Clam Bay NRPA
3. Ensure recreational activities are environmentally compatible within the Clam Bay
NRPA
4. Ensure the estuary has adequate tidal and freshwater flows to maintain ecological
health within the Clam Bay NRPA
5. Monitor, maintain, and where possible and economically feasible, enhance water
quality within the Clam Bay NRPA
1.0 Introduction
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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March 18,2014
Ver.4.2
Purpose of the Management Plan
The purpose of this management plan will be to provide guidance and direction for the
management of the Clam Bay Natural Resource Protection Area (NRPA). This plan will form
the basis by which future management decisions can be made by identifying the appropriate
management techniques necessary to protect, preserve, maintain and monitor the natural
resources and their uses within the Clam Bay NRPA.
This plan, in addition to providing a brief historical perspective of activities undertaken within
this system, will identify management goals and objectives; develop methods to achieve these
goals and objectives; and develop implementation, assessment, and evaluation strategies that
strive to balance resource protection with recreational use. While the 1998 Restoration and
Management Plan focused on mangrove health and recovery, this plan will address all floral and
faunal components of the NRPA, not just the mangroves. The Plan will draw from the 1998
Clam Bay Restoration and Management Plan, input from multiple interested stakeholders, and
the findings of 15 years of biological and hydrographic monitoring activities within the system,
to outline goals and objectives for future management and maintenance of the ecosystems
throughout Clam Bay.
The Clam Bay NRPA Management Plan and any subsequent revisions shall be submitted to the
Collier County Board of County Commissioners (BCC) for approval. Once approved by the
Collier County Board of County Commissioners and relevant regulatory agencies, this Plan will
supersede all others and will serve as the primary guidance tool for future permitting and other
management activities necessary to protect, preserve, maintain, and monitor resources within the
system.
Development of the Management Plan
Turrell, Hall &Associates served as the principal consultant for the management plan. This
consultant firm has a long history of work in the Clam Bay NRPA and was responsible for the
implementation the Clam Bay Restoration and Management Plan (1998)that resulted in the
successful restoration of Clam Bay's mangrove forest. The coastal engineering firm of
Humiston& Moore, Inc. provided input and monitoring data for the 2014 Management Plan
relative to Clam Pass and the dredging activities and templates.
The PBSD Clam Bay Committee consists of members of the Pelican Bay Services Division
Board, which is an advisory board to Collier County's Board of Commissioners, met regularly in
2013 and 2014 and provided input and direction to the consultants. Additional regular input was
provided by representatives of the Conservancy of Southwest Florida; the Mangrove Action
Group; and the local Calusa Group of the Sierra Club. All Committee and Board meetings were
properly noticed, open to the public, and allowed audience participation.
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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Input was also solicited via notices to area businesses, government officials and
employees, condominium associations, and individuals who regularly use Clam Bay. These
representatives were invited to participate in two meetings held in the spring of 2013. They were
also notified in , 2014 that a draft of the management plan was available on the PBSD's
website and they were invited to send their comments to the PBSD's office. (A list of these area
people/organizations is on p. .)
Pelican Bay Services Division Turrell, Hall &Associates
Chairman Tim Hall—Project Manager
801 Laurel Oak Drive, Suite 302 3584 Exchange Ave
Naples, FL 34108 Naples,Fl 34104
(239) 597-1749 (239) 643-0166
Humiston&Moore Engineers
Brett Moore—Project Manager
Mohammed Dabees—Project Engineer
5679 Strand Court
Naples, FL 34110
(239) 594-2021
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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Ver.4.2
Role of the Pelican Bay Services Division
In order for the management and maintenance of the Clam Bay NRPA to be successful,
coordination between a myriad of local, state, and federal agencies and concerned citizen's
groups is required. The Pelican Bay Services Division (PBSD) has undertaken that role for most
of the past fifteen years.
The PBSD is a dependent special district known as the Pelican Bay Municipal Services Taxing
and Benefit Unit. It was formed pursuant to Chapter 125 of the Florida Statutes and was
formally enabled by the Collier County Commission pursuant to Ordinance numbers 90-111 and
91-22. These ordinances were replaced in 2002 by Ordinance 2002-27 which further clarified
the basis and role of the MSTBU and PBSD Board. This MSTBU was created to, among other
things, provide for the maintenance of conservation and preserve areas within Pelican Bay.
This responsibility was undertaken diligently from 1998 to 2009 and resulted in the
implementation of the previous 1998 Management Plan and the recovery of the mangrove die-off
areas. Per action by the Collier County commissioners, the responsibility for many of the
monitoring and maintenance activities associated with the Clam Bay was given to the Collier
County's Coastal Zone Management Department from 2009 to 2012. In 2013, the Collier
County BCC returned responsibility for the monitoring and maintenance of the system to PBSD
via Ordinances 2013-19 and 2013-61. It is under the PBSD's direction that this current
management plan has been written.
While the MSTBU is a dependent special taxing and benefit district, the PBSD is an arm of
Collier County government and makes recommendations to the Collier County Board of County
Commissioners (BCC). The PBSD implements its defined responsibilities within the Pelican
Bay community; sets its own budget and agenda; and regularly submits them to the BCC for
approval. The BCC has regularly approved the Clam Bay management activities and authorized
the development of this Clam Bay NRPA Management Plan. The PBSD's effective working
relationship with the BCC is expected to continue as the PBSD serves as the official manager of
the 2014 Management Plan which is consistent with Ordinances 90-111, 2002-27, 2013-19, and
2013-61 of Collier County.
The PBSD will direct this Management Plan and have the responsibility for its implementation
and operation over time. As such, the PBSD will plan and implement defined management
activities with BCC approval whose purpose will be to protect, preserve, maintain and monitor
the natural communities and ecological integrity of the Clam Bay NRPA.
The PBSD has several attributes which already make it a logical guiding force in the
management and maintenance of Clam Bay. The PBSD:
• Is located within the Clam Bay drainage basin;
• Has an advisory board made up of residential, and business members within Pelican Bay;
• Garners fiscal support collected from local special assessments (non ad valorem taxes);
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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March 18,2014
Ver.4.2
• Is accessible by the public due to its local governing board and advertised public monthly
meetings;
• Has demonstrated a long-term commitment to the Clam Bay NRPA and a successful
track record regarding its preservation, restoration and maintenance over the past fifteen
years.
These attributes give PBSD the knowledge and expertise in matters of local concern and, in
particular, the problems, opportunities and interests of local residents as they relate to the Clam
Bay ecosystem. Its relationship to the BCC gives it an additional level of access to technical
expertise and oversight that will be necessary to assure that the Management Plan, as
contemplated in this document, is fully implemented in the field.
As part of its responsibilities, the PBSD will assemble and distribute various technical reports
and assessments as required under the Management Plan, as well as coordinate with the other
public and private groups interested in Clam Bay. The PBSD is organized for and designed to
maintain both its knowledge of the Clam Bay resources and to generate public support for the
same. PBSD will insure that the general public, residents in Pelican Bay, PBSD consultants, and
representatives from government agencies with jurisdiction over Clam Bay each have on-going
involvement and input into the Management Plan as appropriate.
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Ver.4.2
2.0 Overview of the Clam Bay NRPA
The Clam Bay NRPA is a 570-acre estuarine system consisting of sandy beaches, shallow bays
and creeks, seagrass beds, mangrove forests, and Clam Pass on the west coast of Collier County
in southwest Florida. The Clam Bay system is part of the Cocohatchee-Gordon River Transition,
referred to by Collier County Department of Natural Resources as Coastal Zone II. It is one of
the few remaining estuarine systems in the Cocohatchee-Gordon River Drainage System.
Historically, Clam Bay was tidally connected to the Gulf of Mexico via Wiggins pass to the
north, Doctor's Pass to the south, and centrally located Clam Pass (Collier County, 1994,
Tropical BioIndustries, 1978). These connections were eventually severed with the development
of Vanderbilt Beach Road and Seagate Drive in the 1950s.
Aerial photographs taken prior to the construction of Vanderbilt Beach Road show that the Clam
Bay system was connected to Wiggin's Pass to the north via a system of mangrove swamps and
shallow creeks with intermediate open water areas through the area that was excavated and is
now known as Vanderbilt Lagoon (Collier County, 1994, Tropical BioIndustries, 1978). It is
recognized that the connection was marginal at best and while passable at times, it was not
uniformly and consistently navigable(Clam Bay Restoration and Management Plan, 1998).
Similarly, aerial photos of the Seagate Drive area taken prior to its construction show that Outer
Clam Bay was connected to the mangrove swamps to the south via shallow meandering creeks
and intermediate open waters leading to Doctors Pass. These creeks were only navigable by
canoes and small skiffs (Turrell,2009). These swamps to the south were eventually excavated to
become Venetian and Mooring Bays.
Today,the system includes three primary bays; Outer Clam Bay (southernmost), Inner Clam Bay
(central), and Upper Clam Bay (northernmost), connected by a series of tidal creeks and
connected to the Gulf of Mexico by Clam Pass. The community of Pelican Bay abuts the
northern and eastern edges of the system, while the Seagate and Naples Cay communities abut
the southern portion of the system. This s stem is an im ortant natural and recreational
resource for local residents and visitors. pr
nce 96-1
The Clam Bay system is bounded on the north by Vanderbilt Beach Road and the Bay Colony
portion of the Pelican Bay development, to the south by Seagate Drive, and the Seagate and
Naples Cay developments, to the east by the Pelican Bay development and to the west by the
Gulf of Mexico and the Strand enclave of the Pelican Bay development.
Pelican Bay is predominately a residential community consisting of private single-family homes,
villas, and both high and low-rise condominium units. The community also includes a 27-hole
golf course, common areas with meeting rooms, tennis courts, beach park facilities, emergency
services facilities, and commercial areas with shopping and hotels. The 2,104-acre Planned Unit
Development (PUD) was approved in 1977 as a partnership between Collier Enterprises and
Westinghouse Communities. It was one of the first developments in Florida required to save
fragile coastal wetlands and associated ecosystems (Urban Land Institute, 1981). The
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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March 18,2014
Ver.4.2
development of Pelican Bay had a limited impact on the wetlands themselves (approximately 94
acres in total with about 78 of those acres located in the northwestern corner of the property)
leaving the mangrove forest intact and preserved around the bays. As mitigation for these
wetland impacts, the 570 acre preserve area, including the 35 acre beach park, was donated to
Collier County and eventually became the NRPA which is in place today.
Development of Pelican Bay required a stormwater management system designed to spread
runoff along the eastern edge of the Clam Bay estuary (Collier County Report 1996). A four to
six foot high and 2 '/2 mile long berm separates the developed portion of Pelican Bay from the
estuary lying to the west of the development, but numerous culverts through the berm discharge
water to a swale system along the eastern perimeter of Clam Bay. The eastern edge of Pelican
Bay is about 12-14 feet above sea level at US 41, sloping in an east-west direction to about 2 feet
above sea level near the berm. Six drainage basins operate on a gravity system to slowly move
surface water into the receiving area of Clam Bay.
Naples Cay is a high rise development consisting of 8 multi-story condominium buildings. The
community also includes pools,tennis courts, approximately 33 acres of park and preserve areas,
and two canoe and kayak launching piers. The first building started in Naples Cay in the late
1970's and the last was completed in 2002. Stormwater management is accomplished through
several internal detention areas before water flows into Outer Clam Bay.
The Seagate community is composed of single family residences. The community was first laid
out in the 1950's and still has a few undeveloped lots. Because development of this community
occurred so early, there was no community-wide stormwater management system put in place.
More recent improvements to the road and utility systems have allowed for some dry retention
and sewerage improvements to be put in place. Seagate is the only community adjacent to the
Clam Bay NRPA that is allowed under the County Manatee Protection Plan to have motorized
vessels and the associated boat docks.
Clam Pas Park is a 35 acre County park providing beach access on the south side of Clam Pass.
The park is wholly contained within the NRPA boundary. Access to the park is via a boardwalk
through the mangroves from the parking lot at the very southern end of Pelican Bay.
The Clam Bay system was designated a Natural Resource Protection Area (NRPA) by Collier
County in 1995. The purpose of the NRPA designation is to protect endangered or potentially
endangered species and to identify large connected intact and relatively unfragmented habitats,
which may be important for these listed species (Collier County Growth Management Plan,
Future Land Use Element). See the NRPA timeline (starting on page 15) later in this report for
more details on the NRPA history.
Clam Pass is a small, marginally stable inlet that has migrated north and south along the shore
over the years. Prior to dredging, average water depths of Clam Pass were -2.5' to -1.0', and its
width ranged from 30-50' (Collier County, 1994). The Pass remains the primary source of tidal
exchange for the Clam Bay system, but it is restricted by sediment deposits just inside the pass
and in the long meandering tidal creeks surrounded by mangrove forests.
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
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Approximate extent of Clam Bay NRPA boundary.
Clam Bay NRPA Vital Statistics
Total acres: Approx. 570 acres
Beaches: Approx. 5,000 feet
Beach Park:Approx. 35 acres
Mangrove: Approx. 420 acres
Open Water:Approx. 115 acres
Latitude and Longitude of Pass:N 26° 13' 11",48s,
1", W 81° 49' 01"
Section, Township, Range: Sec. 32 & 33, Twp 48S, Rng 25E, &
Sec. 4, 5, 8, & 9, Twp 49S, Rng 25E
Water Body Identification (WBID) 3278Q1
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
Natural History
Prior to development, the entire coastline of south Florida would have resembled the Clam Bay
ecosystem with meandering mangrove lined shallow waterways buffering sandy barrier islands
and natural terrestrial communities. Unique within the heavily developed coastal community of
Collier County, the Clam Bay estuarine system is a valuable resource for wildlife (particularly
juvenile marine species and birds) as well as residents and visitors to the area who enjoy the
recreational opportunities the system offers such as photography, kayaking, fishing, walking,
swimming, bird watching, and beach going.
The system is a mixture of mangrove-lined tidal creeks, mangrove forests, shallow bays and tidal
passes, seagrass beds, tidal flats, sandy beaches and brackish interior wetlands. It consists of
approximately 420 acres of mangroves and some 115 acres of shallow, open water bays, as well
as a 35 acre beachfront parcel (Clam Pass Beach Park) and approximately 1.5 miles of sandy
beach.
A man-made water management berm now divides natural and developed portions where
historically mangrove forest would have transitioned gradually into the mesic coastal hammocks
and upland pine scrubs that made up the now developed portions of the Pelican Bay community.
A brief overview of these important habitat types, their key characteristics and value is provided
in the Resource Description Section (Section 3.0) of this Plan.
Historical Overview
Historically, Clam Pass was a small part of a large system of relatively shallow waterways and
interconnecting wetland communities extending from Lee County to Doctor's Pass. Anecdotal
evidence suggests that small boating activities took place within many of these interconnected
areas.
During the 1950's this system was isolated from adjacent mangrove lined creeks and bays by the
construction of Seagate Drive to the south and the construction of Vanderbilt Beach Road to the
north. The practical effect was to leave Clam Pass as Clam Bay's only connection to the Gulf.
The Clam Pass opening has moved over its lifetime up and down the shoreline, influenced by
major storm events and by man's alteration of the tidal prism and drainage basin that feeds the
Pass. A detailed discussion of the Pass, as well as aerial photographs of the Pass over time, is
provided in Section 3.0 of this Plan.
To properly understand and successfully implement proposed management objectives, actions
and events which have lead to the current situation in Clam Bay should be described. The
following time lines are intended as background information and as a factual recount based on
anecdotal evidence,press reports, published and unpublished reports.
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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March 18,2014
Ver.4.2
Mangrove Die-off and Restoration
The first mention of stressed or dying mangroves within the Clam Bay NRPA came from a 1978
Tropical Biolndustries and Gee and Jensen report titled Carbon Flows in Portions of the Clam
Pass Estuarine System, Collier County, Florida. Reports of stressed or dying mangroves
continued through the 1980's and 90's. In 1995 a large area of dead and dying mangroves was
documented encompassing approximately 42 acres adjacent to Upper Clam Bay (Turrell, 1996).
By 1999 this area had expanded to approximately 50 acres (Turrell, 2000).
The Clam Bay Restoration and Management Plan was finalized in 1998 to address the mangrove
die-off. The major objective of the plan was to restore the dead mangrove area through
improvements to the tidal flushing capabilities of the system, including enhancements to tidal
flow into and out of the mangrove forest areas. This was accomplished through the dredging of
Clam Pass and portions of the interior channels within the system, as well as construction of a
network of hand-dug flushing channels throughout the original die-off area and a few other areas
that were exhibiting stress.
In the fifteen years following the implementation of the CBRMP the mangrove forest has
undergone a substantial recovery with over 90% of the original die-off area re-vegetated with
new mangrove growth.
Time Line of Important Events Within the Clam Bay System
1920
A dirt road is built by Forest Walker running from the north-east to south portion of Pelican Bay,
a forerunner of US 41.
1950
Clam Bay ecosystem is part of a connected system of barrier islands, mangrove forest, passes
and waterways. The orientation of the beaches and passes would have changed seasonally and
with storms.
1952
Vanderbilt Beach Road is constructed, eventually severing connection with the Wiggins Pass
system to the north.
1958
Construction on Seagate Drive is completed severing flow into and out of the mangroves
swamps to the south which will soon be dredged and excavated to become Venetian Bay.
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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March 18,2014
Ver.4.2
-
Vanderbilt Lagoon
r •—'�
Outer Clam Bay
Upper Clam Bay
1.1
tt '
Venetian Bay
Circa 1952 Aerial Photograph Circa 1960 Aerial Photograph
1972
Tri-County Engineering produces reports:
• An Ecological Study of the Clam Pass Complex is published by Humm& Rehm
• Hydrographic Investigation of the Clam Bay System
Coral Ridge-Collier Properties, Inc. (a partnership between Westinghouse and Collier Properties)
acquired the property and initiated development of Pelican Bay.
1974
Pelican Bay Improvement District is formed to manage common property in Pelican Bay and
provide for long term sustainable infrastructure.
1976
Three, bi-directional 24-inch culverts are placed under Seagate Drive to provide hydrologic
connection to Venetian Bay.
Report"Environmental Assessment for Development Approval" is prepared for Pelican Bay.
Clam Pass closed and was mechanically dredged by dragline to re-open the entrance; no records
of quantities or dredge limits are available.
1977
Pelican Bay Planned Unit Development is approved, and construction commences.
1977-1979
Gee & Jensen Hydrographic Engineers conduct a series of tidal studies within the system and
distribute "A hydrographic study of Clam Bay system" in 1978.
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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March 18,2014
Ver.4.2
1978
Tropical Bio-Industries produce a report: Carbon Flows in portions of the Clam Pass estuarine
system.
Ecological assessment work by Tropical Bio-Industries for permitting of the north-west fill area,
notes a small area of stressed and dead mangroves close to Upper Clam Bay.
1979
Environmental Assessment of the northwest fill area is distributed.
Tropical Bio-Industries produce biological reports:
• A comparative study of the water and carbon flows of Upper Clam Bay
• Invertebrate Population Studies in the vicinity of Upper Clam Bay
1981
Clam Pass closed and was mechanically dredged by dragline to re-open the entrance; no records
of quantities or dredge limits are available.
WCI, the developers of Pelican Bay, transferred title to Clam Bay to Collier County with the
stipulation that Clam Bay shall remain a conservation/preservation area in perpetuity.
1982
WCI deeded Clam Pass Park and Clam Bay to Collier County and in accordance with the Pelican
Bay PUD, required the County to seek approval of WCI or its successors for any modifications
to Clam Bay.
1983
Tropical Bio-Industries produce biological reports:
• Fish populations of tidal ponds west of Upper Clam Bay
• Populations of Melampus coffeus (Coffee bean snail) and Cerithidea scalariformis (Ladder
hornsnail) west of Upper Clam Bay
1986
Collier County constructs a 2,900'boardwalk to provide access to the county park, south of Clam
Pass.
1988
Clam Pass closes twice, first in the spring and again in the late fall after Tropical Storm Keith
(November 23, 1988).
1989
Small areas of stressed and dying mangroves are noted by residents in the basin west of Upper
Clam Bay and east of The Strand in Bay Colony. A Department of Natural Resources (DNR)
interdepartmental memo highlights cause of the stress as "the lack of adequate water circulation
resulting from the closure of Clam Pass".
11
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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March 18,2014
Ver.4.2
1989
First emergency dredging permit received from DNR to re-open clogged Clam Pass, following
memo by David Crewz to the DNR highlighting problems and danger if the Pass was not re-
opened.
Clam Pass was mechanically dredged to re-open. Approximately 700 cubic yards of material
were removed from the mouth of the inlet and the south bend of the channel. Material was
placed south of the Pass. Multiple closures of the inlet occurred during the construction process.
1990
Pelican Bay Improvement District becomes a dependent district of Collier County called the
Pelican Bay Services Division.
1992
The area of dead mangroves is reported at 7 acres.
1994
20 acres of mangroves are reported dead.
1995
Clam Bay is approved by the Board of County Commissioners as Collier County's first Natural
Resource Protection Area(NRPA).
Clam Pass closes following a winter storm event. Emergency dredging permit issued allowing
opening of the Pass, but no work farther back than 600 feet. Mechanical dredging is undertaken
removing approximately 5,000 cubic yards of material from the entrance of the pass.
1996
Clam Pass closes following a winter storm event. Permits to open Clam Pass received from
FDEP and USACE. Mechanical dredging event carried out at the entrance of the Pass.
In summer and fall blasting and hand excavation were permitted and completed in 1997.
Mangrove die-off area estimated at 50 acres.
1997
Clam Pass, on the verge of closing following a winter storm event is mechanically dredged again
under modification to 1996 Permits. Interior portions of the flood shoal were dredged to station
6+10.
1998
Clam Pass was on the verge of closing again following a winter storm event. A mechanical
maintenance dredging event was carried out under modification to 1996 Permits. Interior
portions of the flood shoal were dredged to station 6+10.
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
Ten year permits received from FDEP and USACE for dredging Clam Pass and the interior
channels. Included adjustments to the Seagate culverts and installation of hand dug channels
throughout the system. Associated monitoring work and storm and freshwater studies were
required.
1999
Dredging work associated with the CBRMP was implemented (Mgmt by PB SD) in the spring by
Ludlum Construction Company. Hydraulic dredging of Cuts 1, 2, 3, and 4 were carried out. A
30 foot entrance cut was dredged.
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Ellicott Series 370HP Pumping Sand out of Clam Pass (1999)
One way flap valves installed on Seagate culverts to allow flow from south to north.
Staff at The Conservancy of Southwest Florida commences a 3-5 year study of mangroves,
surface water level and elevation within the mangrove die-off area.
2000
Hurricane Gordon impacts the area with no inlet closure.
2002
Hydraulic maintenance dredging of Clam Pass flood shoals between stations 3+10 and 18+00
(Mgmt by PBSD) completed to improve tidal circulation. The entrance of the pass was not
dredged during this event.
Flap valves on Seagate culverts removed due to insufficient head differential causing them to act
as plugs instead of valves.
Canoe trail markers permitted and installed throughout Clam Bay system.
13
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
2004
Hurricane Charley passes approximately 30 miles west of Clam Pass. A lot of sand was
redistributed but the Pass did not close. Extensive limb and leaf loss was documented within the
mangrove forest.
2005
Hurricane Wilma comes ashore about 30 miles south of Clam Pass. More limb and leaf loss is
noted. Pass did not close.
4
" e *. : a , x
Via.°
Hurricane damaged mangroves along bay 2005 Same mangroves along bay 2007
2007
Hydraulic maintenance dredging of Pass and entrance channel was conducted between Stations 0+00
and 18+00. The entrance of the Pass was dredged at 80 foot width. (Mgmt by Collier County Coastal
Zone Management Dept.).
2008
Tropical Storm Fay comes ashore about 30 miles south of Clam Pass. The area received over 10
inches of rainfall. Pass not affected.
2009
1998 FDEP and USACE permits for maintenance of the Pass expired after 1-year extensions.
2010
Permits issued to continue maintenance of hand-dug flushing channels throughout the system.
2011
White mangrove die-off was observed in central portion of the system and found to be caused by a
bark beetle infestation of trees that had suffered cold temperature stress.
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
Benthic Habitat Assessment study completed within the Clam Bay NRPA by the Conservancy of
Southwest Florida. Study provides comprehensive mapping of benthic habitat compositions and
distribution throughout the Clam Bay NRPA.
2012
Canoe trail markers and informational signage installed throughout Clam Bay.
The mouth of Clam Pass moves to the north near the Pelican Bay Beach Store. The northern shoreline
of the Pass is temporarily reinforced with the installation of concrete barriers.
Impacts from tropical storms Debby and Isaac, along with numerous winter storm fronts caused the
closure of the Pass.
2013
A single event mechanical dredge is carried out in March under FDEP and USACE permits with an
entrance cut of 45 feet. Beach compatible material is placed north and south of the pass above the
mean high water line.
Development of a new Management Plan is initiated through stakeholder input and multiple public
meetings.
Time Line specific to the establishment of the Clam Bay NRPA
1976
Collier County Ord. 76-30 zoned coastal areas environmentally sensitive lands as ST(Sensitive
Treatment)
1977
Approval of the Pelican Bay PUD (Ord. 77-18) by Collier County. The PUD identified 98 acres of
coastal mangrove wetlands to be filled in for development while preserving 570 acres of ST lands as
the Pelican Bay Conservation Area. (35 acres in the south and 5 acres in the north would become parks
providing public beach access).
1981-82
Department of Army Permit (79K-0282) authorized the fill of the 78 acres of coastal wetlands (76
acres for residential development and 2 acres for public parking area). It required 570 acres including
Upper, Inner, and Outer Clam Bays, and their adjacent wetlands to be conveyed to Collier County and
to remain a conservation/preservation area in perpetuity for the use of the public. It also prohibited
dredging Clam Pass except to keep it open to the Gulf of Mexico.
1988
The Pelican Bay Conservation Area (570 acres)was approved and recorded as FL-64P by Congress
and became part of the Federal Coastal Barrier Resources System (CBRS).
15
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
1995
The Collier County Board of County Commissioners approved the County Natural Resources
Department's recommendation to establish the County's first Natural Resource Protection Area
(NRPA); stipulating that that it would have the same boundaries as the Pelican Bay Conservation Area
within the Pelican Bay PUD.
The Collier County Manatee Protection Plan is approved. It contains the recommendation to establish
an "Idle Speed/No Wake"zone throughout the Clam Bay/Clam Pass System.
1996
Collier County Ordinance 96-16: "The Clam Bay System Water Safety and
Vessel Control Ordinance" is approved. It establishes that the Clam Bay System is an "Idle Speed/
No Wake"zone.
1998
The Clam Bay Restoration and Management Plan (CBRMP) is developed, implemented, and managed
by the PBSD and their consultants.
FL Admin. Court Case No. 98-0324GM provided an interpretation that certain elements of the Collier
County Growth Management Plan(Conservation and Coastal Management Element)require protection
of habitats within NRPAs which support existing and potential uses by wildlife.
2008
Public Law 110-419 was adopted identifying the Coastal Barrier Resource System, Clam Pass Unit,
FL-64P to be entirely located within the existing boundaries of the Clam Bay NRPA.
2013
Work begins on new Clam Bay NRPA Management Plan under PBSD direction.
16
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
3.0 Resource Description and Assessment
SOILS
Based on the National Resource Conservation Service (NRCS) "Soil Survey of Collier County Area,
Florida" (NRCS, 1998) there are 2 different soil types (soil map units) present within the NRPA
boundary.
It is important to understand that where the soil survey shows mapping units named for soil series, the
units represent the dominant undisturbed soils in that landscape that existed predevelopment. The unit
descriptions do not recognize or appropriately interpret the drastically disturbed nature of urban
landscapes created after the soil survey was completed.
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Durbin and Wulfert mucks, frequently flooded (Map Unit #40), covers approximately 66% of the
NRPA. These level,very poorly drained soils are most often found in association with tidal mangrove
swamps. Mapped areas can consist entirely of either Durbin or Wulfert or any combination of the two
soils. Individual areas are elongated and irregular in shape and range from 50 to 1000 acres. The
slope is 0 to 1 percent. The permeability of the Durbin soil is rapid and the available water capacity is
high. The permeability of the Wulfert soil is rapid and the available water capacity is moderate. The
water table fluctuates with the tide and is within 12 inches of the surface most of the year. The soil is
subject to tidal flooding. The natural vegetation within these areas consists of red, white and black
mangroves.
Canaveral-Beaches Complex (Map Unit #42) covers approximately 9%of the NRPA.
This map unit consists of the nearly level, moderately well drained Canaveral soil on low ridges and
beaches. Individual areas are elongated and irregular in shape and range from 20 to 300 acres. The
slope is 0 to 2 percent. Typically, beaches consist of sand mixed with shell fragments and shells and
are subject to frequent wave action. The permeability of the Canaveral soil is rapid to very rapid. The
available water capacity is very low. In most years, the seasonal high water table is at a depth of
between 18 to 40 inches for 1 to 4 months. This soil is subject to tidal flooding under severe weather
17
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
conditions. Natural vegetation consists of sea oats, sea grape, cabbage palm, and salt grasses. They are
commonly invaded by exotics such as Australian pine and Brazilian pepper.
TOPOGRAPHY
Topography is shown below using a Light Detecting and Ranging map (LIDAR) obtained from Collier
County. The elevations within the NRPA boundary range from +5.0 to -7.0 NAVD88. The
surrounding lands are generally higher than the NRPA and generate the freshwater flows into the
preserve.
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18
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
CLIMATE
Clam Bay's climate falls within the USDA subtropical classification. There are essentially two
seasons experienced. The wet season occurs in the summer, and the dry season occurs in the winter.
Typical rainfall and temperature data are provided in Tables 4.1 and 4.2.
In the summer the center of the trade winds shift north and moisture-laden breezes blow from the east
or south-east. In winter the trade winds shift southward and the winds are less constant. Weather is
then more influenced by fronts advancing from the northwest. This brings cooler conditions, although
temperatures rarely reach freezing, due to the fact that they are being moderated by the surrounding
waters. Cold fronts are typically preceded by winds from the southwest, which clock to the west then
northwest as the front passes, with strong winds of 20-25 knots and cooler air. In general terms,winds
are predominantly southeast during the summer and northeast during the winter.
Historical meteorology for Clam Bay is based on data collected for 30 years (from 1981 to 2010) from
the Naples Municipal Airport by the Florida Climate Center (NOAA & FSU). The following charts
present meteorological statistics for temperature and precipitation.
1981-2010 TEMPERATURE AND PRECIPITATION NORMALS GRAPH
110.0
100.0
90.0 0—*0
! #' IMPAIWW.0Oar
—.•
70.0 �
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60
•
50.0
40. 1
30.0
20.0
10.0
0.0 .. . * "
Jan M 31 May °E:: Nov
Q Precip(in) 1 0 Min Tmp{"F} 0 Avg Tmp (OF) 0 Max Imp('F)
Table 4.1
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
Temperature
The monthly average temperatures range from 64.5°F to 83.2°F. The lowest monthly minimum
temperature is 54.2°F while the highest monthly maximum temperature is 91.2°F. The data reflect a
humid subtropical climate with a narrow fluctuation in air temperature.
Precipitation
Average annual rainfall for the Naples Municipal Airport NOAA station is documented at 51.89
inches. The data in the table indicates the highest rainfall occurs during the summer months of June,
July,August, and September.
1981-2010 TEMPERATURE AND PRECIPITATION NORMALS CHART
0 Precsp (ire) 0 Min Tmp( H Q Avg Tmp F) 0 Max Tmp IF)
January 1 8 542 64.5 74.7
February 2.10 566.8 66.9 76.9
March 2.38 60.0 70.0 79.9
April 2 3 63.4 73.3 83.2
May 3 1 68.5 78.2 87.8
June 8 82 73.9 81 9 89 9
July 7.27 74,9 83 1 91.2
August 8 5 75.3 83 2 91.0
September 7.69 74.8 82 4 89 9
October 4 1 70 0 78 5 86 9
November 2 0 62.9 721 81.2
December 1 4 57.0 66 8 76.6
Table 4.2
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
Winds
Winds are predominantly easterly throughout the year, but with a tendency to become northeasterly
from October to April and southeasterly from May to September. Wind speeds, not including storm
events are, on average, below 10 knots. During the winter months when fronts move through, for a
day or two at a time,winds out of the northwest to northeast may increase to about 25 knots.
Sea breeze
As the land surface around Naples and Clam Bay warms, the air above is heated. The warm air is less
dense and tends to rise creating a lower air pressure over the land than the water. The cooler air over
the water then flows inland creating a sea breeze. In the evening the reverse occurs and the cooler air
over the land will flow back toward the water creating a land breeze.
The incoming sea breeze acts as a lifting mechanism, resulting in the warmer air rising up to higher
altitudes. This creates cumulus clouds that begin to build which leads to the development of afternoon
showers and thunderstorms in the area.
Storms
Naples and Clam Bay specifically are within the Atlantic Tropical Cyclone basin. This basin includes
much of the North Atlantic, Caribbean Sea, and the Gulf of Mexico. On average, six (6) to eight (8)
tropical storms form within this basin each year. The hurricane season lasts from June 1st to December
1st. The formation of these storms and possible intensification into mature hurricanes takes place over
warm tropical and subtropical waters. Eventual dissipation or
Saffir—Simpson Hurricane Scale
modification, averaging seven (7) to eight (8) days later, typically
Category Wind speed Storm surge
occurs over the colder waters of the North Atlantic or when the
mph a storms move over land and away from the sustaining marine
(km/h) (m)
X156 >1 a environment.
Five
(2250) (>5.5)
' '-'S5 1
3 '
Four Due to the destructive nature of these storms, landfall can result in
`21c-24 ) 0.0-5.5) significant damage to upland development and facilities from storm
111-130 9-12
Three (1713-209) (2.7-3.7) surge, waves, and wind. A good example of this would be
96-110 6-8 Hurricane Wilma which formed in 2005.
Two
(154-177) (16-2.4)
One 74-95 4-5 A tropical storm is defined by maximum sustained winds from 35-
(119-153) (12-1.5) 64 knots (40-74 mph). A hurricane has maximum sustained winds
Additional classifications that exceed 64 knots (74 mph). Hurricanes are classified into
Tropical 39-13 different categories according to the Saffir-Simpson scale.
storm (63-11T) (0-09) Hurricanes can also spawn severe weather such as tornadoes as they
Tropical 0-38 0 move inland.
depression (0-62) (0)
The table below lists the number of tropical storms and hurricanes
that passed through or near Naples over the past 20 seasons including 1992 through 2012 as reported
21
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
by the National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center and
Hurricane City (www.hurricanecity.com). Analysis of the available information indicates that Naples,
on average, is brushed or hit by a tropical storm or hurricane once every 2.71 years and is directly hit
once every 7.05 years.
Table 4.4 Number of Named Storms Passing through or near Naples
Year #of Storms Names Strength closest to Naples
1992 1 Andrew Hurricane Cat. 3
1993 0
1994 1 Gordon Tropical Storm
1995 1 Jerry Tropical Storm
1996 0
1997 0
1998 1 Mitch Tropical Storm
1999 1 Harvey Tropical Storm
2000 1 Gordon Tropical Storm
2001 0
2002 0
2003 0
2004 1 Charley Hurricane Cat.3
2005 1 Wilma Hurricane Cat.2
2006 0
2007 0
2008 1 Fay Tropical Storm
2009 0
2010 0
2011 0
2012 0
2013 0
Hurricane Wilma image
ItiO ilio
}
22
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
NATURAL COMMUNITIES
In this Section, a natural community refers to the mix of plant and animal species that form the natural
basis of the Clam Bay NRPA. A combination of factors including geology, climate,hydrology, soils,
and anthropogenic influences determines the specific types of plants found in any given area. These
plants are a major factor in what type of animal species that may be present. The Florida Department
of Transportation's Land Use, Cover, and Forms Classification System (FLUCFCS 1999) has been
used to identify the plant communities found within the Clam Bay NRPA.
FLUCFCS Community Description Upland or %of Clam Bay
Code Wetland NRPA
181 Swimming Beach Upland 5.95
186 Community Recreation Facilities Upland 0.40
322 Coastal Scrub Upland 3.98
428 Cabbage Palm Hammock Upland 0.45
540 Bays (with and without direct Wetland 23.16
connection to Gulf or Ocean)
612 Mangrove Swamp Wetland 64.60
642 Saltwater Marsh Wetland 0.04
651 Tidal Flat Wetland 1.44
911 Seagrasses** Wetland 0.84**
** included in the Bays (541) category
Several other components of the Clam Bay NRPA ecosystem are also addressed below. These
components include offshore hardbottom, oyster and other benthic faunal communities that are not
specifically addressed in the FLUCFCS classification system. Additional historical information on the
Clam Bay mangrove and seagrass habitats is included as appendices to the Plan.
FLUCFCS Code 181 - Swimming Beach
Beaches form when offshore sand deposits are moved landward by wave action usually during the
spring and summer. Sand, which is stirred up as the wave breaks on the shore, drops out of suspension
as the water moves up the beach face. Thus, the beach becomes gradually higher, wider, and steeper.
In the wintertime, larger, higher energy waves associated with winter storms overflow the beach area
and stir up the sand deposited earlier in the year. The sand is pulled off the beach as the wave recedes
and is deposited in an offshore sand bar. If these two forces are in equilibrium, the beach area will be
stable from year to year. However, naturally occurring factors such as storm events, littoral drift
(lateral movement of sand because waves approach the beach at an angle), and offshore winds, upset
this equilibrium and result in the ever shifting nature of the beach environment.
Dunes form because of onshore wind action on beach sand. When wind speeds are sufficient,
individual grains of sand start to roll and bounce along the surface. This windborne sand is transported
23
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
landward until the wind speed drops below that needed to move the sand. Coastal vegetation is critical
for slowing wind speeds and causing sand to be deposited.
Landward of the highest tides, pioneer or frontal zone sites are stabilized by sand trapping action of
various rhizomatous grasses and low growing shrubs that are tolerant of salt spray. Only a few plant
species can tolerate the stresses of a dune environment, particularly frontal dune sites. Foredune plants
must be able to survive being buried by blowing sand, sand blasting, salt spray, salt water flooding,
drought, heat, and low nutrient supply. Coastal plants colonizing the dunes are key players in trapping
windblown sand and preventing coastal erosion as the first defense against heavy winds and surge of
tropical storms.
Many plant species that occur on dune areas have developed specific attributes to help them survive these harsh
environments. These include high growth rates, dense root systems, low profiles, and high flower and seed
production rates. Species common on the beaches of the Clam Bay system include; Sea oats (Uniola
paniculata), Seagrape (Coccoloba uvifera), and Railroad vine (Ipomoea pes-caprae).
There is approximately 8,675 linear feet of shoreline within the Clam Bay NRPA in three distinct
segments separated by the two Pelican Bay Foundation beach facilities. Contiguous beach habitat
extends from the NRPA habitat both north and south along the coast. Shorebirds feed on marine
invertebrates such as coquina clams and mole crabs at the water's edge and beaches are crucially
important habitat for nesting sea turtles.
This particular habitat has been monitored periodically in terms of width as part of the Collier County
Beach renourishment program though no conclusive statements can be made about the floral or faunal
details of the ecotone over the years. Large scale generalizations based on the annual aerial
photographs can be made that the overall size, composition, and health of the habitat have remained
relatively stable and, with the exception of the areas immediately adjacent to the Pass, are mostly
unaffected by the status of the Pass. 44,01 4
' 1 ". ; *V
444:It 104-0,elx.„iii- 4714.
Beach habitat within NRPA Boundary
24
CLAM BAY NRPA T)
Pelican BayMANAGEMENT ServPLANices Di(DRAFvision
March 18,2014
Ver.4.2
FLUCFCS Code 322 - Coastal Scrub
Landward of the frontal (Beach) zone area is the back dune zone (also often called the shrub or scrub
zone), a portion of the dune that is more stable, has greater organic matter, and supports less salt
tolerant grasses and shrubs as well as some trees.
Many of the woody species found incoastal scrub are low growing and shrubby due to low nutrient
and droughty conditions of sandy soils. High winds and salt spray often prune the terminal buds of the
trees and shrubs growing on the dunes and result in salt-pruned, windswept canopies.
Coastal scrub is represented by a conglomeration of coastal species generally found in at narrow band
between the Mangrove forest and the beach areas. Species common on the beaches of the Clam Bay
system include; Seagrape (Coccoloba uvifera), Cabbage palm (Sabal palmetto), Buttonwood
(Conocarpus erectus) and Spanish bayonet (Yucca aloifolia). This is an important habitat as it helps
anchor the back dune sands and provides habitat for several listed plant and animal species including
the gopher tortoise (Gopherus polyphemus).
The primary management issues of concern in the coastal scrub are gopher tortoise habitat
management and exotic vegetation control.
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25
(DRAFT)DRAFT)CLAM BAY NRPAMPelican Bay
4.2
Ver.
4
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FLUCFCS Code 428- Cabbage Palm Hammock
;Ii
This forested zone is composed of the more protected dune vegetation farthest from the ocean. The
Cabbage Palm Hammock habitat is identified by the preponderance of cabbage palms (Sabal
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if
4.
palmetto). It is generally found in pockets located between the mangrove forest and the coastal scrub
or beach areas. Aside from the cabbage palms, sea grapes (Coccoloba uvifera), buttonwood, and
several other hammock species such as wax myrtle and myrsine are common. A hammock is a habitat
that is densely shaded by a canopy of trees. Hammocks usually have a sparse groundcover that leaves
the forest floor mostly open for animals to travel through. Hammocks also provide a reprieve from the
sun for animals and humans alike. In Clam Bay, this habitat is also susceptible to infestation by exotic
vegetation such as Australian pine and Brazilian pepper which are addressed further on in this Section.
The primary management issues for this habitat are exotic control and preventing destructive visitor
access.
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eta
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a
Palm habitat within NRPA Boundary
26
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
FLUCFCS Code 540—Bays (with and without connection to the Gulf)
The Clam Bay NRPA contains the three larger bays associated with Clam Pass (Outer, Inner, and
Upper) as well as the interconnecting shallow creeks and small open water areas. Second in extent of
aerial coverage within the NRPA boundary, it is the bays and interconnections which serve as the life
blood of the estuary.
This open water habitat serves as the basis for many other communities. Seagrass beds, oyster bars,
clam beds, and other benthic communities can all be supported to varying degrees with the open waters
of the bays and interconnecting creeks. As outlined below, several of these communities are present
within the Clam Bay NRPA and will be considered when deciding on management activities outlined
within this Plan
Multiple studies have indicated that the single most important thing that can be done to restore the
health of the Clam Bay system is to improve the total tidal flushing capacity of the system (Tackney
1996; Lewis 1996; Wilson Miller, et al 1996; Turrell 1996.). The dredging conducted within the Pass
and the interconnecting creeks, as well as the hand-dug flushing cuts, have been seen as the major
contributing factors to the restoration of the mangrove forest community within the system (Turrell
2008; Humiston& Moore 2003).
Tidal Pass
Clam Pass is the only open water connection to the Gulf of Mexico for the Clam Bay NRPA. The
exchange of seawater between Clam Bay and the Gulf is critical to the ability of the estuary to export
organic matter, as well as to help regulate excess salt and freshwater. It also supplies oxygen rich
water from the Gulf. In the absence of surface water circulation or tidal activity, estuarine habitats
such as mangroves can slowly die due to deleterious changes in the sediment: 1) in the absence of
oxygenated water, the sediments become anaerobic or anoxic, and 2) metabolic wastes and hydrogen
sulfide accumulate in the anoxic sediment(CBRMP, 1998).
Tides in the Gulf of Mexico are mixed, with the norm being two high tides and two low tides
experienced per day and normal amplitude (range) of approximately 2 feet. The highest tides (springs)
are experienced twice per lunar month at full and new moons when the gravitational pull on the earth's
surface waters is greatest. Neap tides also occur twice per lunar month when the planetary
(gravitational) influences of earth, moon and sun are perpendicular.
27
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
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28
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
It can be seen that the health of mangrove forests is directly related to the efficiency of the tidal pass.
Clam Pass and its associated waterway is a very dynamic creek whose location has varied over time
(Turrell 1995; Tackney 1996). Because of this, it is susceptible to outside events and can periodically
close, such as has happened at least six times in the last 25 years.
The following aerial photographs show how the Pass and its waterway have changed over the past 60
years.
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29
i
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
i „
March 18,2014
Ver.4.2
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Tidal creeks are passageways for fish and marine invertebrates between the open waters of the Gulf
and the protected embayments of Clam Bay. Manatees and turtles may also use the Pass. Scouring
action of the fast flowing tide generally prevents colonization by seagrasses and other benthic plants
and the substrate is typically sand and shell with the finer sediments carried in suspension and
deposited just outside the mouth of the pass (the ebb shoal delta) or to the interior of the system on the
incoming(flood)tide.
Management concerns related to the bays and associated creeks include maintaining sufficient flow
through them to accomplish flushing needs of the system, stabilization of the Pass without harming
other components of the NRPA, and educating recreational users of the NRPA of the need to protect
the shallow water habitats and the communities located therein.
30
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
♦ 4
.` �. '„i?.r gyp' ,,p, ��' '�. a+ ` ?; i r .
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Open Water habitat within NRPA Boundary
FLUCFCS Code 612—Mangrove Swamps (Forest)
Mangroves are salt tolerant trees that grow in tidal areas of the tropics and are legally protected for
their ecological value,with such functions as;
• Providing habitat for marine,terrestrial and avian wildlife.
• Protecting coastal areas from storm surges and coastal erosion.
• Improving water quality by acting as a natural filter for land based freshwater run-off.
• Forming the basis of a highly productive estuarine food chain which includes many commercially
valuable species.
• Enhancing the atmosphere by absorbing carbon dioxide and reducing greenhouse gasses.
Approximately 65%of the Clam Bay NRPA is composed of the three most common mangrove species
in Florida, namely red mangroves (Rhizophora mangle), black mangroves (Avicennia germinans), and
white mangroves (Laguncularia racemosa) make up the mangrove forests within the Clam Bay NRPA.
All three species have special biological adaptations to cope with salt and unstable, mucky, low
oxygen soils that result from the tidal, hence continually waterlogged, environment. The dominance of
mangroves in tidal areas is a function of these adaptations and their ability to out-compete other
wetland plants. Tidal flushing allows nutrients to be distributed within the forest and provides for the
transportation of dead leaves, twigs, etc. As this material decays, it becomes food for marine life. It is
this mangrove detritus which is consumed by the many organisms at the base of the food chain and
which in turn create the next level of the food chain necessary to support the fish populations that
characterize the mangrove community.
Special attention has been given to the mangrove community in the past because of the die-off which
occurred between 1991 and 1997 (though stress in the community was documented as far back as the
late 1970's). The die-off affected black and red mangroves initially but eventually ended up
encompassing some white mangroves as well. More details on the recent history of the mangrove
management are provided in Appendix 1 included with this plan.
31
CLAM BA YNRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
Red Mangroves
Red mangroves (Rhizophora mangle) are recognized by their tangle of reddish looking prop roots, long
cigar shaped seedlings and their large, pointed evergreen leaves. Red mangroves flower all year but
reach maximum propagule production during the late spring and early summer months. They are
typically the most seaward of the three species with the prop roots and vertical drop roots providing
support, small pores on the trunks called lenticels allow oxygen exchange via air as the waterlogged
soils become rapidly oxygen depleted. Salt is excluded from the plants cells through a process called
ultra-filtration in the roots. The characteristic propagules germinate on the parent tree and drop and
float for up to a year, finally becoming heavier at one end so that when encountering a suitable
substrate they are ready to root upright. The mass of prop and drop roots forms extensive surface area
under water for attachment of sessile, filter feeding marine species (such as sponges, tunicates and
mollusks) as well as hiding places for juvenile fish. Birds, butterflies, insects and mammals find home
and food within the canopy.
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Red Mangroves and •Propagules (inset)
32
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
Black Mangroves
Black mangroves (Avicennia germinans) are typically found a little further inland and key
identification features include the snorkel like pneumatophores which radiate upwards out of the soil
from the base of the trunk, agrey-black rough bark and slightly pointed, oval leaves which are silvery
with salt deposits on the undersides. The pneumatophores play an important role in oxygen exchange
and unlike the red mangroves, which keeps salt out of body cells through filtration in the roots; the
black mangrove excretes salt out of the backside of the leaves. They are also reliant on adequate tidal
exchange but lack the supporting prop roots that typify the red mangrove. Small white flowers and
lima bean shaped propagules are typically apparent during the late spring and early summer months.
Black mangroves are cryptoviviparous as the embryo develops within the fruit while on the parent
plant. When these propagules fall from the parent tree, they are able to float for a short period before
rooting in the mucky soil.
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Black Mangrove Pneumatophores
33
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,
Ver.2014 4.2
White Mangroves
White mangroves (Laguncularia racemosa) are the third mangrove species and are often found further
inland than the other two species (although zonations described are typical they can frequently vary).
Since they often occur in drier areas, white mangroves do not exhibit the adaptations to soft, anaerobic
soil of the other species. The bark is characteristically grooved and furrowed and leaves are oval, mid-
green and leathery with two small glands on the petiole at the base of each leaf. White mangroves also
flower in the spring and early summer and the small seedlings have the shortest floating dispersal stage
of the three species. White mangroves are semi-viviparous and germinate inside the fruit during the
approximately five day dispersal, but not while attached to the parent plant
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White Mangrove leaves and fruit
34
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
The mangrove communities are composed of both riverine (along the creeks) and basin forest
components. The species composition of mangroves within these two community components is very
distinctive. Riverine mangrove areas are almost exclusively composed of red mangroves within the
Clam Bay NRPA while all three species, along with buttonwood are found in the forest component.
Riverine (Creeks)Mangroves
On the waterward edges of small islands and the tidal creeks, passes and estuarine waterways that
make up the Clam Bay system, a fringe of red mangroves will be found growing up to 25 feet in
height. This zone can be just one or two trees in depth or extend landward for some distance,
depending on topography. The habitat provided by the prop roots of these red mangroves is of great
importance to many fish and other aquatic organisms.
Forests
The majority of the Clam Bay mangrove habitat is low-lying basin forest where the dominant
mangrove species varies between red, white, and black throughout the forest habitat. This forest
community was the habitat affected by the mangrove die-off. The hand dug flushing channels were
constructed throughout this community to increase the flushing capacity through tidal inundation.
Associated plants within the mangrove habitat include Buttonwood (Conocarpus erectus), the
succulent groundcovers Saltwort (Batis maritime) and Glasswort (Salicornia cervicornis), (especially
where a fallen tree provides a break in the canopy and light penetration to the forest floor) and, further
inland and closer to freshwater sources,the Leather fern (Acrosirichum danaefolia).
- cf. - .* 'if 7.1"1-C;1;11;
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Mangrove habitat within NRPA Boundary
FLUCFCS Code 642 - Salt Marsh
At the interface between forested mangrove areas and the water management berm are depressional
areas that have become colonized by aquatic freshwater plants such as cattails (Typha latifolia),
Carolina willow (Salix caroliniana), Bulrush (Scirpus californicus), Needlerush (Juncus romerianus)
and Leather fern (Acrostichum danaeifolium). Wildlife such as otters (Lutra canadiensis), alligators
35
•
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
(Alligator mississippiensis), various turtles, and wading birds can be commonly observed. These areas
require regular maintenance to prevent the spread of nuisance and exotic plant species and ensure
, ,
optimal functioning and interface between the natural mangrove forest and the development water
management system.
- - 7°491". *ft'. ' It l'. till'1;\ \''''''t1:: "..:ik:'''N t t'''' i"°17.7%.,7'_'14' .'; '47-4..qt
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ilt. - 1-TO' *.kNe,,, r , ,',ist. *,„ 't.ACt,r ' ..,,,,, t4,, ,, .. , -ir, ! 77 '
z
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Marsh habitat within NRPA Boundary
FLUCFCS Code 651 -Tidal Flats
Tidal flats are flat bottomed, sub- or intertidal habitats that lack an oyster or seagrass community and
are located inside the outer coastal margin. The two most significant environmental characteristics that
control a flat's infauna (benthic organisms that live within the substrate) and epifauna (benthic animals
that live on the surface of a substrate) are: the height of the substrate relative to mean sea level and the
sedimentary consistency of the substrate. The position relative to mean sea level dictates whether the
habitat is emergent (in air) for part of a tidal cycle or how deep below the water it is. This latter
characteristic controls other physical water quality measures, such as dissolved oxygen, the frequency
and duration of hypoxic events, and light penetration. Firmness of the substrate affects the capacity to
support an epifauna by both supporting the organism on the substrate and permitting the burrowing of
the infauna.
The sand and mudflats of Clam Bay are rich feeding grounds for many species of fish and wading
birds. These organically rich sediments support a variety of mollusks, worms and invertebrates that
scavenge detritus or, in the case of many bivalve mollusks, extend siphons at high tide and filter vast
quantities of water. Birds such as a variety of herons, ibis, egrets and spoonbills pick through the
sediment for the invertebrate food sources.
The dredging of the pass associated with the 1998 Restoration and Management Plan resulted in an
increase of exposed tidal flats within the southern portion of the system. Increased tidal range
resulting from the dredging allowed more area to be periodically exposed during the tidal cycle. Some
of the area that had supported seagrasses prior to the dredging work were converted into the tidal flats
36
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services March Divisi18on
Ve,
r.4.2
by the increased range and reduced phase lag. Management concerns related to the tidal flats include
the templates established for the dredging, the resultant currents that could be expected as a result of
dredging, and the frequency of disturbance.
,. ,wriiilk. „„..... ii.v..1 ,73.,401", *.r,V.--.44140.9 e
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Tidal Flat habitat within NRPA Boundary
FLUCFCS Code 911 - Seagrass Beds
Seagrasses are flowering marine plants of shallow, tropical regions. With a creeping growth form
connected by horizontal rhizomes they serve to trap and anchor sediment. Both the grass blades
themselves and the surface area they represent provide food and attachment for marine species.
Seagrass beds are renowned for their value as nursery habitats and are legally protected.
Several areas within the Clam Bay system host seagrass beds, specifically Outer Clam Bay and
waterways just inside Clam Pass. Three species are commonly found in these Clam Bay waters; the
largest Turtle grass (Thalassia testudinum) with flat strap shaped leaves, the smaller shoal grass
(Halodule beaudettei (fka wrightii)) with narrow, flat blades and Paddle grass (Halphila decepiens)
with the smallest, paddle shaped leaves. Shoal grass is by far the most common though ad
small area of
turtle grass has persisted since the original 1998 dredging. Paddle grass is much more ephemeral in
nature and diligence is required to be able to locate it during the time frames when::,,t,,.i,ms:,..,:e.se,n,..
t.
v v � �.���s a '`411 ,�� �. =, �._,a. .,. ' ���.�3�+°*"-'"� ��l �p ».F � ,irk. � „„.....;i k isrp
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Seaygrass habitat within
NRPA Boundary
37
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
_ .' .. n r °,;�* ,. •*tom r + .c,}
n
r - L,
'
,i
"w" a f ',rV`•�`7+ „tea-_
�> � "` 1' ,rte V. ' F�' - -
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or
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Shoal grass (Halodule beaudettei)along interior channel south of Clam Pass
. R
* �
Paddle grass (Hcrlphila decepierrs) in center of Outer Clam Bay
38
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
�r „ .
kt
+ '� sw < tea,
Turtle grass(Thalassia testudinum)just south of County boardwalk in Outer Clam Bay
Seagrasses rely on good light penetration to enable photosynthesis and are sensitive to reduced tidal
water quality. Growing in shallow regions they are also vulnerable to physical damage by boats. A
variety of marine algae can be associated with grass species, differing in the lack of a true rooting and
vascular system. Several species of both brown and green alga have been observed.
Seagrass coverage in Clam Bay has varied over time but has always been found predominately in
Outer Clam Bay and the waterway between this bay and Clam Pass. A 1994 Collier County report
estimated seagrass coverage at approximately 10 acres. Pre-dredge surveys conducted in 1999
estimated coverage. at about 5.13 acres. Annual monitoring of seagrass beds along the monitoring
transects have estmated coverage from a low of approximately 1.2 acres in 2003 to the current
estimate of 2.85 acres from the 2013 survey. It should be noted that the coverage estimates are taken
from along the survey transects only and do not account for other scattered grasses that may be located
elsewhere in the system.
Management concerns related to seagrasses include direct impacts due to recreational use and potential
dredging templates,turbidity and water quality concerns related to flushing (too much or too little) and
stormwater inputs, and algal infestations due to nutrient increases.
A history of the seagrass monitoring efforts in Clam Bay is •included in the Appendix 2 attached to this
report.
39
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
Other Benthic Habitats
Oyster Bars
Oysters (Croassostrea americana) are filter-feeding bivalves, which were once common within the
tidal creeks of Clam Bay (Humm and Rehm 1972). Oysters play a significant role in shaping the
environment in which they live by forming a hard structure upon which an intricate biological
community is built. Similar to coral reefs, oyster reefs are `biogenic' (formed by the accumulation of
colonial animals) and provide structure and surface area for numerous other temporary and permanent
species.
Providing complex habitat structure is the most fundamental of ecosystem services that oysters
provide. The structure provides a place for algae and non-mobile invertebrates to attach, as well as a
place for mobile invertebrates and fishes to be protected from predators. Although the relationships
between sportfish and oyster habitats are not as well studied as in other estuarine habitats such as
seagrass beds,they are considered essential fish habitat.
The numerous ecosystem services provided by oysters can be summarized into three general
categories: habitat provision, water quality improvement, and shoreline stabilization. Oyster reefs
provide habitat to a diverse array of flora and fauna. The role of oyster habitat to the estuarine food
chain is highly significant, as discussed in the previous paragraph. Through their feeding process
oysters filter large quantities of water which transfers energy and material from the water column to
the benthic community, subsequently reducing turbidity and water column nutrients. Through bio-
deposition, nutrients are made available to the flora and fauna which comprise the complex oyster bar
food web. Additionally, oyster reefs stabilize sediments, shorelines and adjacent habitats by buffering
wave energy, further aiding water quality.
Deteriorating conditions related to closures of Clam Pass is thought to have resulted in the
disappearance of oyster bars in the system; though some re-occurrence has been observed to the south
of the pass in the last few years during seagrass transect monitoring. Oysters have been documented
around the perimeter of Outer Clam Bay in past years monitoring efforts.
OYSTER PHOTO
40
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
A 2011 benthic habitat assessment conducted by the Conservancy of Southwest Florida found living
oyster clusters in the upper reaches of Upper Clam Bay (a single cluster), in the tributary between
Outer and Inner Clam Bays (a single cluster), and throughout the shoreline of Outer Clam Bay.
Management concerns related to oyster growth are similar to the seagrass concerns, namely protection
from recreation users,water quality, and flushing.
iIleri ..
# i. :41FYI
r .
. a
kE:
Other bivalve mollusks
In addition to oysters,the 2011 benthic habitat assessment conducted by the Conservancy of Southwest
Florida also found two other bivalves within the Clam Bay system. The pointed Venus clam
(Anomalocardia auberiana) and the stout razor clam (Tagelus plebeius) were both observed. Turrell,
Hall and Associates benthic surveys found several beds of southern hard clams (Mercenaria
campechiensis) also present within the system.
a, ;
ya`
Southern hard clam (Mercenaria campechiensis) from waterway south of Clam Pass
41
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
These mollusks are generally found within the shoal and tidal flat areas of the system and could be
susceptible to impact during dredging or other disturbance operations. Management concerns would
be protection from recreational users,water quality, flushing, and dredging.
ADD Polychaete Worms per KW
Hardbottom Communities
Another important marine habitat marginally associated with the estuarine system is the hard bottom
reef community found just seaward of Clam Pass. In about 10-15 feet of water a variety of sponges,
stony corals, gorgonians, fish and associated invertebrates can be found within a system of rocks and
ledges. Outcroppings of similar habitat type occur along the length of Collier County and are a little
known resource of regional significance.
Hardbottom outcrop off of Clam Pass
Collier County has mapped this resource through side scan sonar surveys in 2005 and 2009 as part of
its beach renourishment project. The information received from the County shows that the landward
edge of this habitat is located approximately 250 to 300 feet offshore from the Pass.
42
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
4
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Management concerns related to this habitat include recreation use and potential turbidity impacts
resulting from dredging or other management activities within the Clam Bay NRPA.
Invasive,Non-native and Problem Species
In an ecological context, an invasive species is one that is aggressive in growth and expansion of range
and tends to dominate other appropriate native species. Its establishment and dominance can cause
widespread harm to an ecological system by altering the species composition, susceptibility to fire and
hydrology of an area. Non-indigenous species (i.e., non-native or exotic species)are those that have
been introduced purposefully or accidentally to an area outside their normal range. The characteristics
of some of these species (high rate of growth/reproduction, no natural predators, easily dispersed, able
to out-compete native species)make them invasive. Some indigenous species (a species whose natural
range included Florida at the time of European contact circa 1500 AD or a species that has naturally
expanded or changed its range to include Florida)may also become invasive. Invasions by native and
non-native species often follow an alteration to ecosystem function, disruption of the food web, large-
scale fragmentation of an ecosystem and/or disturbance (e.g., clearing, fire, drought, etc.) of an area.
While some native species may become invasive,the establishment and dominance of non-native
species is of particular concern. The exotic species documented within the NRPA and those that have
a potential to occur within the NRPA are discussed in the following section.
Invasive and Problem Plant Species
The Florida Exotic Pest Plan Council (FLEPPC)maintains a list of exotic plans that have been
documented to (1)have adverse effects on Florida's biodiversity and plant communities, (2) cause
habitat loss due to infestations, and (3) impact endangered species via habitat loss and alteration. To
date, 9 non-indigenous plant species have been detected within the Clam Bay NRPA which are listed
by FLEPPC as Category. I exotics. FLEPPC defines Category I plants as those that alter native plant
communities by displacing native species, change community structures or ecological functions, or
hybridize with natives. Category II plants have increase in abundance or frequency but have not yet
altered Florida plant communities to the extent shown by Category I species. These definitions do not
rely on the economic severity or geographic range of the problem, but rather on the documented
ecological damage caused by these plants(FLEPPC 2013).
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FLEPPC Category 1 plants observed within the Clam Bay NRPA boundary:
- Brazilian Pepper(Schinus terrebinthifolius)
- Melaleuca(Melaleuca quinquenervia)
- Australian Pine (Casuarina equisetifolia)
- Beach Naupaka(Scaevola taccada)
- Earleaf Acacia(Acacia auriculiformis)
- Shoebutton Ardisia (Ardisia elliptica)
- Air Potato (Dioscorea bulbifera)
- Lantana(Lantana camara)
- Old World Climbing Fern (Lygodium microphyllum)
FLEPPC Category II plants observed within the Clam Bay NRPA boundary:
- Coconut Palm (Cocos nucifera)
- Wedelia(Sphagneticola trilobata)
- Oyster Plant(Tradescantia spathacea)
- Mahoe (Talipariti tiliaceum)
Methodology outlining the management activities that will be used to treat exotics is found in Chapter
5 of this Plan.
LISTED SPECIES
Smalltooth Sawfish (Pristis pectinata)
A juvenile smalltooth sawfish was observed in 2008 in the connector creek between Inner and Outer
Clam Bays. Smalltooth sawfish are found in the tropical and subtropical Atlantic Ocean. In the
western Atlantic they have historically ranged from New York to Brazil, including the Gulf of Mexico
and Caribbean Sea. Habitat destruction and overfishing have succeeded in eradicating the smalltooth
sawfish from the majority of its former range. Consequently, it survives in small pockets throughout its
current range. The last remaining population in U.S. waters is off south Florida, a small remnant of a
population that once ranged from New York to Texas.
This sawfish primarily occurs in estuarine and coastal habitats such as bays, lagoons, and rivers. It
does at times occur in deeper waters, however, and may make crossings to offshore islands. It can
tolerate freshwater. This fish is easily recognized by its flattened body and wing-like pectoral fins. The
mouth is located ventrally, the eyes are positioned dorsally. The "saw" is approximately 25% of the
body's total length. It is widest at the base, with teeth more broad than long, and spaced apart. The tips
of the teeth are sharp, becoming blunt over time. Dorsally, it is brownish or bluish gray body with a
white underside. The maximum length recorded is 24.7 feet (7.6 m); however, a length of 18 feet (5.5
m) is considered average. The average lifespan for the smalltooth sawfish is unknown.
On April 1, 2003 the U.S. National Marine Fisheries Service placed the smalltooth sawfish on the
Endangered Species List, making it the first marine fish species to receive protection under the
Endangered Species Act. Florida has also designated critical habitat areas to further protect its habitat.
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Mangrove Rivulus (Rivulus marmoratus)
This small fish has not been identified within the Clam Bay system in previous surveys or field work
but the mangrove habitat is appropriate and they could be present in the upper reaches of the mangrove
forest. The mangrove rivulus is primarily a saltwater or brackish water species, with limited
occurrence in freshwater. Within the Everglades and along Florida's west coast, this fish occurs in
stagnant, seasonal ponds and sloughs as well as in mosquito ditches within mangrove habitats. The
mangrove rivulus is able to survive in moist detritus without water for up to 60 days during periods of
drought, anaerobic, or high sulfide conditions.
This fish can reach a maximum size of 2 inches (5 cm) in length, however it is more commonly
observed at lengths between 0.4-1.5 inches (1.0-3.8 cm). The head and body are maroon to dark
brown or tan, with small dark spots and speckling on the body, particularly the sides. The dorsal
surface is always darker than the creamy ventral surface. The color of the body is reflective of the
habitat, with light coloration in areas of light colored sediments and darker coloration in environments
with dark leaf litter substrates. A large dark spot surrounded by a band of yellow is located at the upper
base of the caudal fin in hermaphroditic individuals. Males lack this dark spot and have a red-orange
cast to their flanks and fins.
The mangrove rivulus was once listed as a threatened species in the Gulf of Mexico. However, recently
additional surveys have revealed the existence of numerous populations. In Florida it has been
downlisted to a species of special concern. In 1999, it was submitted by the National Marine Fisheries
Service as a candidate for protection under the Endangered Species Act. As of yet, it has not been
officially listed as endangered or threatened.
The main threat to the survival of the mangrove rivulus is habitat degradation and destruction as well
as exposure to pollutants. Disturbances that alter salinity and temperature as well as vegetation cover
may also reduce naturally occurring populations.
Loggerhead Sea Turtle (Caretta caretta)
Loggerhead sea turtles have been documented nesting on beaches within the Clam Bay NRPA.
Loggerheads are circumglobal, occurring throughout the temperate and tropical regions of the Atlantic,
Pacific, and Indian Oceans. They are the most abundant species of sea turtle found in U.S. coastal
waters. In the Atlantic, the loggerhead turtle's range extends from Newfoundland to as far south as
Argentina.
During the summer, nesting occurs primarily in the subtropics. Although the major nesting
concentrations in the U.S. are found from North Carolina through southwest Florida, minimal nesting
occurs outside of this range westward to Texas and northward to Virginia. Adult loggerheads are
known to make extensive migrations between foraging areas and nesting beaches. During non-nesting
years, adult females from U.S. beaches are distributed in waters off the eastern U.S. and throughout the
Gulf of Mexico, Bahamas, Greater Antilles, and Yucatan.
Loggerheads were named for their relatively large heads, which support powerful jaws and enable
them to feed on hard-shelled prey, such as whelks and conch. The top shell (carapace) is slightly heart-
shaped and reddish-brown in adults and sub-adults, while the bottom shell (plastron) is generally a pale
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yellowish color. The neck and flippers are usually dull brown to reddish brown on top and medium to
pale yellow on the sides and bottom.
In the southeastern U.S., mating occurs in late March to early June and females lay eggs between late
April and early September. Females lay three to five nests, and sometimes more, during a single
nesting season. The eggs incubate approximately two months before hatching sometime between late
June and mid-November.
Loggerheads occupy three different ecosystems during their lives: beaches (terrestrial zone), water
(oceanic zone), and nearshore coastal areas ("neritic" zone). Because of this,NOAA Fisheries and the
U.S. Fish and Wildlife Service (USFWS) have joint jurisdiction for marine turtles, with NOAA having
the lead in the marine environment and USFWS having the lead on the nesting beaches.
The loggerhead turtle was first listed under the Endangered Species Act as threatened throughout its
range on July 28, 1978. In September 2011,NMFS and U.S. Fish and Wildlife Service listed 9 Distinct
Population Segments of loggerhead sea turtles under the ESA. The population in our Northeast
Atlantic Ocean Segment is listed as endangered. The agencies are currently proposing Critical Habitat
designations on several areas which contain a combination of nearshore reproductive habitat, winter
area, breeding areas, and migratory corridors. The Clam Bay NRPA is contained within the LOGG-N-
27 segment of this proposed critical habitat area.
Gopher Tortoise (Gopherus polyphemus)
Gopher tortoises and their burrows are found along the coastal strand portions of the Clam Bay NRPA.
The range of the tortoise includes southern portions or Alabama, South Carolina, Louisiana,
Mississippi, and Georgia as well as most of Florida.
Gopher tortoises are one of the few species of tortoise that dig burrows. These burrows can be up to ten
feet deep and 40 feet long, and are as wide as the length of the tortoise that made it. In addition to
providing the tortoise a home, it has been documented that as many as 350 other species also use the
burrows including the indigo snake, Florida mouse, gopher frog and burrowing owl.
Gopher tortoises can live 40 to 60 years in the wild and average 9 to 11 inches in length. These
tortoises are superb earth-movers, living in long burrows from 5 to 45 feet long and up to 10 feet deep
that offer refuge from cold, heat, drought, forest fires and predators. The burrows maintain a fairly
constant temperature and humidity throughout the year and protect the gopher tortoise and other
species from temperature extremes, drying out, and predators. The mating season generally runs from
April through June and gestation for the eggs is between 80 and 100 days.
The shell or "carapace" of the gopher tortoise is mostly brownish gray and the underside of the shell, or
"plastron," is yellowish tan. Their front legs are shovel-like which helps them when digging their
burrows.
The gopher tortoise has been regulated in Florida since 1972 and has been fully protected since 1988.
Despite the afforded protection, gopher tortoise populations throughout the state have declined. As a
response to the continuing decline of the species, a new management plan was drafted and approved in
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September 2007 as a precursor to reclassifying the gopher tortoise from a "species of special concern"
to a "threatened species." The threatened status was approved and went into effect on November 8,
2007.
Piping Plover(Charadrius melodus)
Piping plovers have been rarely sighted foraging or resting along the shoreline within the Clam Bay
NRPA boundaries. No nesting activities have been documented within the NRPA.
Piping plovers are small shorebirds approximately seven inches long with about a 19 inch wingspan.
They have sandy/grey colored plumage on their backs and crown and white underparts. Breeding birds
develop a single black breast band, a black bar across the forehead, bright orange legs and bill with a
black tip on the bill. During the winter, the birds lose the black bands, the legs fade to pale yellow, and
the bill becomes mostly black.
Piping plovers breed in three geographic regions of North America: the Atlantic Coast(which is where
the Clam Bay NRPA is located), the Northern Great Plains, and the Great Lakes. Nesting in the
Atlantic Coast region occurs on coastal beaches, sand flats and bars associated with barrier islands,
gently sloped and sparsely vegetated dunes, and washover areas cut into or between dunes. Plovers
from all three breeding populations winter along South Atlantic, Gulf Coast, and Caribbean beaches
and barrier islands, primarily on intertidal beaches with sand and/or mud flats with no or very sparse
vegetation.
Piping plover populations were federally listed as threatened and endangered in 1986. The Northern
Great Plains and Atlantic Coast populations are threatened, and the Great Lakes population is
endangered. Piping plovers are considered threatened throughout their wintering range. The highest
concentration of birds reported in winter censuses are found in Texas, Louisiana, and Florida. In recent
decades, piping plover populations have drastically declined as breeding habitat has been replaced with
shoreline development and recreation. (USFWS).
West Indian Manatee(Rivulus marmoratus)
Manatees have been sighted on numerous occasions within the Clam Bay NRPA boundaries. Manatees
can be found in shallow, slow-moving rivers, estuaries, saltwater bays, canals, and coastal areas
particularly where seagrass beds or freshwater vegetation flourish. Manatees are a migratory species.
Within the United States, they are concentrated in Florida in the winter. In summer months, they can
be found as far west as Texas and as far north as Massachusetts, but summer sightings in Alabama,
Georgia and South Carolina are more common.
Manatees are large, gray aquatic mammals with bodies that taper to a flat, paddle-shaped tail. They
have two forelimbs, called flippers, with three to four nails on each flipper. The average adult manatee
is about 10 feet long and weighs between 800 and 1,200 pounds. They eat a large variety of
submerged, emergent, and floating plants and can consume 10-15% of their body weight in vegetation
daily. Because they are mammals, they must surface to breathe air. They rest just below the surface of
the water, coming up to breathe on an average of every three to five minutes. It is believed that one
calf is born every two to five years, and twins are rare. The gestation period is about a year. Mothers
nurse their young for one to two years, during which time a calf remains dependent on its mother.
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Protections for Florida manatees were first enacted in 1893. Today, they are protected by the Florida
Manatee Sanctuary Act and are federally protected by both the Marine Mammal Protection Act and the
Endangered Species Act
PLANT SPECIES -List to be added based on FL UCFCS Mapping
ANIMAL SPECIES
The following lists of species have been observed within the Clam Bay NRPA and the adjacent Pelican
Bay development areas. These lists are not all inclusive but represent a wide array of the species found
within and adjacent to the Clam Bay NRPA habitats.
Aquatic Invertebrates—Add from Conservancy Report
Fish
COMMON NAME SCIENTIFIC NAME
Atlantic needlefish Strongylura marina
Barracuda Sphyraena barracuda
Bay anchovy Anchoa mitchilli
Blacktip Shark Carcharhinus limbatus
Blue crab Callinectis sapidus
Cowfish Acanthostracion quadricomis
Flounder Paratichthys alb!gutta
Gray snapper Lutjanus griseus
Great barracuda Sphyraena barracuda
Gulf killifish Fundulus grandis
Inshore Iizardfish Synodus foetens
Killifish spp. Fundulus spp.
Leatherjacket Oligoplites saurus
Longnose killifish Fundulus simitis
Mangrove snapper Lutjanus griseus
Mullet Mugil cephalus
Mutton snapper Lutjanus anatis
Needlefish Strongylura marina
Permit Trachinotus falcatus
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Pigfish Orthopristus chrysoptera
Pinfish Lagodon rhomboides
Pipefish Syngnathus spp.
Puffer Sphoeroides parvus
Sailfin molly Poecilia latipinna
Sand perch Diplectrum bivittatum
Scaled sardine Harengula pensacolae
Sea robin Prionotus scitulus
Sheepshead Archosargus probatocephal
Sheepshead minnow Cyprinodon variegatus
Silver jenny Eucinostomus gula
Smalltooth Sawfish Pristis pectinata
Snook Centropomus undecimalis
Spot Leiostomus xanthurus
Spotfin mojara Eucinostomus argenteus
Spotted seatrout Cynoscion nebulosus
Tidewater silverside Menidia peninsulae
Triggerfish Batistes capriscus
White grunt Haemulon plumierii
Whiting Menticirrhus tittoratis
Reptiles and Amphibians
COMMON NAME SCIENTIFIC NAME
SNAKES
Banded water snake Nerodia faciata faciata
Black racer Coluber constrictor
Common garter snake Thamnophis sirtalis
Eastern coachwhip Masticophis flagellum
Mangrove salt marsh water snake Nerodia clarkii
Mud snake Farancia abacura
Red rat snake Elaphe guttata guttata
Ring-necked snake Diadophis punctatus
Yellow rat snake Elaphe obsoleta
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LIZARDS AND CROCODILIANS
American alligator Alligator mississippiensis
Brown anole Anolis sagrei
Brown basilisk lizard** Basiliscus vittatus
Cuban knight anole** Anolis equestris
Eastern glass lizard Ophisaurus ventralis
Green anole Anolis carolinensis
Southeastern five-lined skink Eumeces inexpectatus
FROGS AND TOADS
Cuban treefrog Osteopilus septentrionalis
Eastern narrow-mouthed toad Gastrophryne carolinensis
Eastern spadefoot toad Scaphiopus holbrookii
Giant marine toad** Rhinella marina (fka Bufo marinus)
Green treefrog Hyla cinerea
Oak toad Anaxyrus quercicus
Southern leopard frog Lithobates sphenocephalus
Southern toad Bufo terrestris
Squirrel treefrog Hyla squirella
TURTLES AND TORTOISES
Chicken turtle Deirochelys reticularia
Florida box turtle Terrapene carolina bauri
Florida redbelly cooter Pseudemys nelsoni
Florida snapping turtle Chelydra serpentina osceola
Florida softshell turtle Apalone ferox
Gopher tortoise Gopherus polyphemus
Green sea turtle Chelonia mydas
Loggerhead sea turtle Caretta caretta
Penninsula cooter Pseudemys peninsularis
Pond (yellowbelly) slider Trachemys scripta scripta
Striped mud turtle Kinosternon baurii
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Birds
COMMON NAME SCIENTIFIC NAME
American avocet Recurvirostra americana
American coot Fulica americana
American kestrel Falco sparverius
American oystercatcher Haematopus palliatus
American Robin Turdus migratorius
Anhinga Anhinga anhinga
Bald eagle Haliaeetus leucocephalus
Barred owl Strix varia
Belted kingfisher Megaceryle alcyon
Black skimmer Rynchops niger
Black vulture Rynchops niger
Black-and-white warbler Mniotilta varia
Black-bellied plover Pluvialis squatarola
Black-crowned night heron Nycticorax nycticorax
Black-necked stilt Himantopus mexicanus
Blue jay Cyanocitta cristata
Blue-gray gnatcatcher Polioptila caerulea
Boat-tailed grackle Quiscalus major
Brown pelican Pelecanus occidentalis
Brown thrasher Toxostoma rufum
Budgerigar Melopsittacus undulatus
Caspian tern Hydroprogne caspia
Cattle egret Bubulcus ibis
Chuck-will's-widow Caprimulgus carolinensis
Common grackle Quiscalus quiscula
Common ground-dove Columbina passerina
Common moorhen Gallinula chloropus
Common nighthawk Chordeiles minor
Common snipe Gallinago gallinago
Common tern Sterna hirundo
Common yellowthroat Geothlypis trichas
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Double-crested cormorant Phalacrocorax auritus
Dowitcher long-billed Limnodromus scolopaceus
Dowitcher short-billed Limnodromus griseus
Downy woodpecker Picoides pubescens
Dunlin Calidris alpina
Eastern screech owl Megascops asio
Eurasian collared dove Streptopelia decaocto
European starling Sturnus vulgaris
Fish crow Corvus ossagus
Forster's tern Sterna forsteri
Glossy ibis Plegadis falcinellus
Gray catbird Dumetella carolinensis
Great blue heron Ardea herodias
Great crested flycatcher Myiarchus crinitus
Great egret Ardea alba
Great horned owl Bubo virginianus
Greater yellowlegs Tringa melanoleuca
Green heron Butorides virescens
Green-winged teal Anas crecca
Herring gull Larus argentatus
Hooded merganser Lophodytes cucullatus
House sparrow Passer domesticus
Killdeer Charadrius vociferus
Laughing gull Leucophaeus atricilla
Least sandpiper Calidris minutilla
Limpkin Aramus guarauna
Little blue heron Egretta caerulea
Loggerhead shrike Lanius ludovicianus
Magnificent frigate bird Fregata magnificens
Mangrove cuckoo Coccyzus minor
Merlin Falco columbarius
Mocking bird Mimus polyglottos
Mottled duck Anas fulvigula
Mourning dove Zenaida macroura
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Muscovy duck Cairina moschata
Northern cardinal Cardinalis cardinalis
Northern gannet Morus bassanus
Northern parula Parula americana
Northern waterthrush Seiurus noveboracensis
Osprey Pandion haliaetus
Painted bunting Passerina ciris
Palm warbler Dendroica palmarum
Peregrine falcon Falco peregrinus
Pied-billed grebe Podilymbus podiceps
Pilleated woodpecker Dryocopus pileatus
Piping plover Charadrius melodus
Prairie warbler Dendroica discolor
Purple gallinule Porphyrula martinica
Red knot Calidris canutus
Red-bellied woodpecker Melanerpes carolinus
Red-breasted merganser Mergus serrator
Reddish egret Egretta rufescens
Red-shouldered hawk Buteo lineatus
Red-tailed hawk Buteo jamaicensis
Red-winged blackbird Agelaius phoeniceus
Ring-billed gull Larus delawarensis
Roseate spoonbill Platalea ajaja
Royal tern Sterna maxima
Ruby-throated hummingbird Archilochus colubris
Ruddy turnstone Arenaria interpres
Sanderling Calidris alba
Sandwich tern Sterna sandvicensis
Semipalmated plover Charadrius semipalmatus
Snowy egret Egretta thula
Spotted sandpiper Actitis macularia
Swallow-tailed kite Elanoides forfacatus
Tri-colored heron Egretta tricolor
Turkey vulture Cathartes aura
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Western sandpiper Calidris mauri
White ibis Eudocimus albus
White pelican Pelecanus erythrorhynchos
Willet Catoptrophorus semipalmatus
Wood stork Scolopax minor
Yellow-bellied sapsucker Sphyrapicus varius
Yellow-crowned night heron Nyctanassa violacea
Yellow-rumped warbler Dendroica coronata
Yellow-throated warbler Dendroica dominica
Mammals
COMMON NAME SCIENTIFIC NAME
Big brown bat Eptesicus fuscus
Bobcat Lynx ri figs
Bottle-nosed dolphin Turciops truncatus
Brazilian free-tailed bat Tadarida braziliensis
Coyote Canis latrans
Eastern gray squirrel Sciurus carolinensis
Eastern mole Scalopus aquaticus
Feral domestic cat Felis catus
Florida Black bear Ursus americanus floridanus
Gray fox Urocyon cinereoargenteus
House mouse Mus musculus
Marsh rabbit Sylvilagus palustris
Nine-banded armadillo Dasypus novemcinctus
Raccoon Procyon lotor
River otter Lutra canadensis
Roof rat Rattus rattus
Virginia opossum Didelphis Virginia
West Indian manatee Trichechus manatus
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HYDROLOGY
Hydrological regime, sometimes referred to as the surface water or surficial hydrology, in simple terms
describes the long term spatial variation in the water depths and period of inundation within a wetland
system. This is because the surficial hydrology has both horizontal and vertical components and
provides key ecological functions to the mangrove forest. (Lewis, pers. comm. 2008)
With respect to the horizontal component, incoming water (both tidal and surface water run-off) into
an estuary brings with it nutrients, dissolved oxygen, and marginally lower salt concentrations.
Conversely, the outgoing water leaving a mangrove wetland (through tidal exchange) removes
metabolic waste products (e.g., carbon dioxide and toxic sulfides) and excess salt. The vertical
component refers to incoming water that percolates down into the sediment and root zone, and the
sediment drainage, on a falling tide,which removes metabolic wastes and excess salt.
It is the inflow and outflow of sea water that is critical to the ability of the estuary to manage these two
ecological functions and as such dissipate salts, organic matter and freshwater. It follows that anything
that affects the system and alters the ability of the system to perform these functions, will, in most
instances, cause stress to the system and, at some point in time, result in the death of the system, or
portions of it.
Hydrologic studies indicate that the tidal flushing capacity of Clam Bay prior to the restoration
dredging was limited and almost insignificant in Upper Clam Bay. The preliminary hydrographic
assessment of the Clam Bay system prepared by Tackney & Associates, Inc. (August 1996)
demonstrated rather dramatically that there was a significant reduction in tidal range between the
middle boardwalk and Inner Clam Bay. Tackney described the flow in that area as "measurably
reduced" and "very inefficient". This connecting tidal creek is the key conduit for tidal input and
outflow to the northern reaches of the Clam Bay system. And its constriction and the ancillary
constriction of tributaries connection to it, impact the quantity and quality of the flushing that can
occur in Inner and Upper Clam Bay.
Another key aspect of the surficial hydrology is the vertical location of the water level elevation
relative to the sediment elevation. Specifically, the mean low water (tide) elevation has to be
sufficiently lower than the sediment elevation in order for sediments to drain during low tide. A
persistent high surface water elevation stops sediment drainage and results in anoxic sediment and the
accumulation of toxic waste products. The absence of meaningful exchange was certainly a
contributor to the significant degradation of the mangrove system within Clam Bay. (Tackney 1996;
Lewis pers. comm. 2008).
In this context Tackney observed that even in the absence of rainfall, the average water surface
elevations for the inner and upper bays were higher than the average surface elevation for the Gulf.
Analysis of the tidal data indicated that average water surface elevations in the Inner and Upper Clam
Bays were both elevated above the average Gulf water surface elevation by approximately 0.2 feet.
This indicated that the tidal range in Inner and Upper Clam Bays was muted and that the system was
receiving significant additional water through runoff and restricted capacity to drain additional inflow.
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In fact, during portions of the Tackney study no tidal fluctuation was noted in the Upper Clam Bay and
only marginal tidal effects were observed in Inner Clam Bay.
The reduced tidal ranges were also accompanied by relatively large phase lags. The phase lag is the
average time delay measured in hours and minutes between the occurrence of slack(high or low)water
in the Gulf of Mexico and the measurement stations. It is affected by both the distance between
measurement stations and the amount and quality of hydraulic resistance of the connecting channel.
The longer the distance and the higher the resistance, the more pronounced one would expect the phase
lag to be. In the upper bays, high and low waters generally occurred over three hours later than the
Gulf tides.
These conditions indicate that the tidal creeks connecting the interior bays are hydraulically very
inefficient. As a result, the upper bays are prone towards extended periods of flooding as a result of
freshwater runoff and the inability of the system to drain efficiently. During Tackney's field studies of
May 1996, rainfall of approximately 4 inches in three days was adequate to flood the Upper Clam Bay
above high tide levels and sustain this flooded condition for over two days. Accordingly, he concluded
that the creeks and bays that serve to connect the Inner and Upper Bays were significantly less efficient
in the ebb tide stage than they were in the flood stage. Studies undertaken by both Lewis
Environmental Services, Inc. and Turrell & Associates, Inc. would support this conclusion. (Turrell
1995).
Finally, an additional attribute of the system that is directly related to tidal prism and the quantity of
inflow and outflow is the question of inlet stability. Inlet stability refers to a tidal inlet's capacity to
adequately scour out deposited sediments and prevent inlet closure. For a given wave environment,
inlet stability is governed primarily by the volume of water (tidal prism) carried by the inlet. To
remain stable, an inlet must have the characteristic that a temporary constriction in cross sectional area
produces an increase in current velocities adequate to scour out the constriction. To function without
mechanical intervention, the system must generate a sufficient volume of water on the ebb tide to scour
out the inlet naturally, otherwise the inlet will, over time, continue to close. This is particularly true
during periods of high wave activity and low tidal ranges. (Turrell 1995; Tackney 1996). The six
closures of Clam Pass that have occurred in the past twenty-five years indicate that stability of Clam
Pass is marginal. (Turrell 1995; Tackney 1996, Humiston 2010).
Freshwater Component
Under predevelopment conditions, much of the area's rainfall was held on the surface of the land in
sloughs and other low areas. This water would either slowly filter through the soil to recharge the
shallow aquifer or move through the mangrove community to the bay. Less than ten inches of the
approximately 53 inch average rainfall is estimated to have been lost from the uplands east of Clam
Bay as surface runoff. The storage capabilities of the land thus moderated surface flows, preventing
extremely high flow rates during the rainy season and serving to maintain surface flow and
groundwater flow during the dry season. (FDER 1981).
The development of Pelican Bay had limited fill impact to the Clam Bay system, but it did modify the
pattern of freshwater entering the Clam Bay system. (Wilson, Miller et.al. 1996). The stormwater
management system as designed, permitted and implemented at Pelican Bay employs a series of
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CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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Ver.4.2
detention ponds, swales and culverts to regulate the discharge of run-off into Clam Bay. Discharge
occurs almost continuously along the eastern perimeter of the conservation area. Run-off from the
northern end of Pelican Bay is collected and discharged into Upper Clam Bay. Irrigation water for 27
holes of golf and landscaping in Pelican Bay is approximately 3.0 MGD which approximates 26 inches
per year of additional rainfall equivalent, (Wilson, Miller et.al., 1996). When added to the average
rainfall for South Florida of approximately 53 inches per year, the local area has an effective rainfall of
approximately 80 inches plus annually. This is significant, particularly when viewed in the context of
predictable storm events that have the potential for altering the amount of average rainfall entering the
Clam Bay system.
The "Pelican Bay Water Management System — Stormwater Detention Volume and Water Budget
Analysis" (Wilson, Miller, Barton & Peek, Inc. April, 1996) describes the water management system
as being divided into six watersheds or drainage systems. Rainfall, including irrigation, reaches the
ground and either seeps into the ground or runs off to a stormwater detention area within each system.
The stormwater detention plan for Pelican Bay has a standard, permitted design capacity to hold the
first inch of stormwater during a 25-year storm event. The stormwater is detained for flood protection
and water quality treatment. Stormwater discharge is controlled by a series of weirs designed such that
the post-development stormwater run-off rate does not exceed pre-development rates. Stated
differently, the system is designed to discharge stormwater in the development portion of Pelican Bay
in the same manner that it discharged stormwater prior to development. The stormwater discharge
exits the weir system for a final release into Clam Bay.
Stormwater runoff from an additional 130 acres of watersheds, outside of Pelican Bay, contributes an
additional and significant volume of discharge to Clam Bay. This water represents 7.9% of the total
stormwater discharge to Clam Bay.
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CLAM BA Y NRPA MANAGEMENT PLAN(DRAFT)
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Approximate locations of Drainage Basins within the Pelican Bay Development(photo is oriented with north up and west
to the left).
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As the area of Pelican Bay to the east has undergone development, it has increased the impervious
surface area, with a concomitant increase in surface runoff, which is eventually discharged to Clam
Bay. The daily irrigation water volume enhances the saturation of the uplands which reduces their
ability to accommodate rainfall volume, thus effectively increasing surface and groundwater discharge.
Groundwater discharge can be commonly observed throughout-the eastern side of Clam Bay and is
discernable as a very slight sheet flow. Where this water encounters a discharge system, even one that
is not operating at peak efficiency (from an engineering, not historical, standpoint), such as Outer Clam
Bay, excess water is effectively removed from the system. However, in the northern section, sheet
flow was not efficiently removed due to lack of flow through the forest. Thus, it accumulated,
increasing soil saturation and raising the mean water table elevation, and apparently overwhelming the
black mangrove's anaerobic soil/gas exchange mechanisms. Mangroves in these areas became
stressed and died.
WATER QUALITY
During the initial environmental permitting of Pelican Bay, the agencies required water quality testing
within the Pelican Bay subdivision and the Clam Bay estuary to help evaluate the impact of
development on Clam Bay. The water quality-testing program was first implemented by Pelican Bay
Improvement District (PBID) starting in the early 1980's. In 1990, PBID became the Pelican Bay
Services Division (PBSD), a dependent Division of Collier County. PBSD continued the testing
program after 1990. PBSD is currently the responsible entity for the testing program.
The water quality testing is performed at several sample points within Pelican Bay and Clam Bay. The
sample point locations are shown on the exhibit below. There are currently nine sampling locations
within Pelican Bay and Clam Bay. Sample points W-7 (located in the creek near the north Foundation
boardwalk), W-6 (located in the creek near the south Foundation boardwalk), W-1 (located near the
kayak launch area at the southern end of Outer Clam Bay), North Seagate (located on the north side of
the Seagate Culverts between Venetian Bay and Outer Clam Bay), and Upper Clam Bay (located at the
very north end of Upper Clam Bay) are within Clam Bay, which are categorized as Class II waters by
the Florida Department of Environmental Protection (FDEP). The remaining five sampling points are
PB-13 (located north of the Sandpiper parking lot on both sides of the berm), PB-11 (located between
the St. Maarten condominium and the Commons on the east side of the berm), Glenview (located
between the Glenview and Stratford condominiums on the east side of the berm), and St. Lucia
(located adjacent to the St. Lucia condominium on the east side of the berm), are located in the
stormwater treatment portion of the property (Class III waters) within Pelican Bay.
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BAY NRPA MANAGEMENT PLAN(DRAFT)
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March-1 8,201
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Water quality sampling is conducted within the Clam Bay system on a monthly basis. The samples are
collected by PBSD staff and transported to the Collier County Pollution Control laboratory for
processing. Parameters sampled and collected, include;
• Field pH
• Field Temperature
• Field Salinity
• Field Dissolved Oxygen
• Ammonia
• Carbon- Total Organic
• Chlorophyll a
• Copper* (added to the parameter suite in 2013)
• Nitrate-Nitrite (N)
• Nitrite (N)
• Nitrogen- Total Kjeldahl
• Orthophosphate (OPO4)
• Pheophytin
• Phosphorus- Total
• Residues- Filterable (TDS)
• Silica(SiO2)
Water quality sampling results of nutrient loading seem to indicate that the development stormwater
management system is doing its job. No evidence of nutrient loading has been observed within the
Class II waters though several spikes and elevated nutrient (N and P) levels have been observed from
the testing locations along the berm. It is believed that the spikes observed are correlated with
fertilizer application within the community.
The Florida Department of Environmental Protection (FDEP) conducted water quality sampling within
the Clam Bay NRPA in 2001 and 2012. Based on their sample results, FDEP had made an initial
determination that Clam Bay could be impaired for both Dissolved Oxygen (DO) and Copper.
Subsequent coordination between FDEP, PBSD, the Pelican Bay Foundation, and involved
consultants, FDEP made a determination that the oxygen levels in Clam Bay were natural and the
system was not listed as impaired for DO.
FDEP did determine that the system was impaired for copper and was placing the system on the
Everglades West Coast verified list for copper with a medium TMDL priority (5 to 10 years for TMDL
development). Subsequent copper testing undertaken by PBSD has also shown periodic elevated
levels of copper within the Clam Bay Class II waters.
FDEP acknowledged that the Pelican Bay community was working on an upland stormwater and
nutrient management program that was designed to reduce nutrient and copper inputs into the
stormwater system. Once completed, this program can be given to FDEP for review and if satisfied
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with the anticipated reduction of copper resulting from the implementation of the plan,the system
could be removed from the impaired list. While the upland nutrient management plan is not part of
this NRPA Management Plan, PBSD will work closely with the Pelican Bay Foundation to coordinate
and share information, and to integrate management decisions and activities into this Plan where
appropriate.
ARCHAEOLOGICAL RESOURCES
The Florida Division of Historical Resources Master Site File lists three known archaeological sites
within the Clam Bay NRPA boundary. All three are located within the mangrove forest habitat. Two
of the sites (CR476 and CR547) are located north of the Pass and south of Inner Clam Bay. The third
site (CR576) is located south of the Pass and north of the Clam Pass Park boardwalk.
Site CR476 is identified as a prehistoric campsite and shell midden possibly supporting the use of
several cultures dating from 8500 B.C. to A.D. 1700.
Sites CR547 and CR576 are identified as shell middens which were in use between 1000 B.C. and
A.D. 1700.
All three of the sites are within the mangrove forest and outside of the footprint of any previous or
future anticipated dredging activities.
INLET DYNAMICS— To be added from Engineer's report(s)
RECREATIONAL USE
The Clam Bay NRPA provides a variety of opportunities for recreation such as walking, kayaking,
canoeing,paddle boarding, swimming, fishing, and snorkeling. Many Collier County residents and
visitors enjoy the natural environment of the preserve. Recent stakeholder input as well as prior
reports supports the use of the Clam Bay NRPA for recreational endeavors. It is important that all who
participate in recreational activities within the system do no harm to the unique flora and fauna.
Clam Bay's dense forest of mangroves significantly limits walking in the preserve. Most walkers
seeking to enjoy the rich natural environment of Clam Bay use the three boardwalks that cross the
preserve and provide access to the beach. Residents and guests of Pelican Bay residents use the
northern and middle boardwalks. The southern most boardwalk is open to the public and accessed
from the parking lot at the south end of the system. Trams are used on all three boardwalks to transport
those choosing not to walk on the boardwalk to the beach.
Kayaks and canoes are used by those wanting to enjoy the natural setting and serenity of Clam Bay's
waterways. There is a public launching area adjacent to the parking lot at the south end of the bay, and
there is also a private launch for Pelican Bay residents on the northern boardwalk. The canoe/kayak
trail is clearly designated by canoe trail markers from Outer Clam Bay to Upper Clam Bay.
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Fishing and swimming are also popular pastimes. Fishing can be done from the boardwalks and canoes
or by wading into the water. Swimming is usually confined to the beach areas,but some swimmers and
waders, if conditions permit, venture into Clam Pass.
The operation of motorized w� FEraft in Clam Bay is restricted by Collier County Ordinance 96-16
that requires vessels with motors to travel at idle speed with no wake throughout the Clam Bay syle
The relatively shallow waterways of the system, in conjunction with the boardwalk heights, limit t
size and drafts of motorized watercraft. Some residents of the Seagate neighborhood immediately
south of Outer Clam Bay have historically utilized motorized watercraft in Clam Bay but this use is
still subject to the County ordinance. Violation of the ordinance is a civil infraction for which a fine
may be levied. Occasionally motorized vessels, including jet-skis or other personal watercraft, have
been reported to be in violation of the ordinance. Efforts to identify and report violators will continue
to insure that Clam Bay Alb onlylace dirlis AK, but ttsirntA
prowl.In the future should any adverse effects on Clam Bay's natural resources or water quality be
found to be related to motorized watercraft, additional management options will be explored to
ameliorate these adverse effects.
EFFORTS TO AMEND ORDINANCE OR REMOVE ABOVE
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4.0 Authorized Construction Activities
List of permits for work undertaken to date and relevant legal framework
Eighteen years ago, Collier County processed a permit to dredge limited areas of Clam Pass to
facilitate the movement of tidal water in and out of Clam Bay. The FDEP permit for this activity was
issued on March 28, 1996 with the companion USACOE permit being issued on April 2, 1996. The
FDEP permit was modified on April 10, 1996 with the authorized work being undertaken and
completed on April 17, 1996. The practical effect of implementing this Permit was to reopen the Pass,
but it was clear that without a more comprehensive strategy, this effort, standing alone, would not
revitalize the Clam Bay ecosystem.
A permit to improve the channel flow within defined areas of the Clam Bay system by a combination
of blasting and hand excavation was issued on June 26, 1996. The work was undertaken and
completed in two segments. The first channels were opened in August 1996 and the second channels
were opened in November 1996. The results of these two initiatives were positive in that measurable
improvements in tidal flow were discernible and with that have come improved conditions for natural
re-vegetation.
A permit was issued on January 5, 1997 to construct a portable pump and pipe system as an interim
measure to divert freshwater within the Clam Bay system to the Gulf while a more permanent solution
contemplated by the construction of an outfall structure was reviewed. Although this plan was never
implemented and is no longer considered, it envisioned two pumps that would be operational when the
water surface elevation within Clam Bay exceeded a specified threshold. The plan anticipated the
direct discharge of excess water into the Gulf with the expectation that this system would augment the
natural discharge through the tidal mechanism after severe storm events.
Subsequently, Collier County authorized the pursuit of a ten-year permit to allow the County, or its
designee (which in this case was the Pelican Bay Services Division), to maintain Clam Pass in an open
condition. The application, as filed, did not address any other issues affecting the operational
characteristics of Clam Bay and essentially mirrored the 1996 Permit described in the first paragraph
above. Agency comments and concerns which arose as part of the permit review led to the creation of
the 1998 Clam Bay Restoration and Management Plan. The Plan addressed agency concerns at the
time and included provisions for adding one-way flap gates to the Seagate culverts, dredging within
three sections of the creek north of Clam Pass, a network of hand dug channels throughout the forest
area, in addition to the dredging of the Pass. This permit was issued in 1998 and the Management Plan
created in support of the permit has been the guiding document for the maintenance activities
undertaken in the Clam Bay system since then.
It is anticipated that FDEP and USACE 10-year permits will be sought in conjunction with this new
Management Plan. The permits will allow for ongoing maintenance and/or enhancement activities to
continue along with occasional, modest removal of material by dredging within a discreet area of Clam
Pass in order to maintain the existing tidal regime within the system. Any changes to the submitted
dredging scope or other new management initiatives will be reviewed by the PBSD Board and Collier
County Commissioners before seeking any additional permit(s) which may be necessary for the
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modified activities. Additional investigations which may be undertaken at a later date to look at, for
example, faunal investigations, more in-depth water quality concerns, or other issues that may arise as
a result of stakeholder discussions could also necessitate permitting which will have to be reviewed by
the PBSD and BCC prior to any such permit applications being submitted. This Management Plan is
specifically tasked to maintain the improvements and benefits already realized and to insure that the
restoration success observed to date is continued. Dredging for navigation or beach renourishment will
not be done.
The following list contains more details related to existing and historical permits issued for the Clam
Bay system.
Permit Details
South Florida Water Management District Surface Water Permit No.: 11-00065-S
Date of Issue: August 10, 1978
Expiration Date: Operational phase doesn't expire
Project Description: To construct and operate water management systems 1 and 2 serving 539 acres of
residential lands discharging by westerly sheet flow to Inner, Outer, and Upper Clam Bays.
Department of Environmental Regulation Construction Permit/Certification No.: 11-50-3769
Date of Issue: May 23, 1979
Expiration Date: May 15, 1984
Project Description: To provide construction sites for residential development in a planned community
by: placing approximately 700,000 cy of clean upland fill material onto approximately 94 plus acres
of submerged lands of waters of the state landward of the line of mean high water.
Department of the Army Corps of Engineers Permit No.: 00754929
Date of Issue: November 18, 1981
Expiration Date: November 18, 1984
Project Description: This permitted the filling of 75± acres of mangrove wetlands north, east and west
of Upper Clam Bay and south of Vanderbilt Beach Road.
Department of Environmental Regulation Modification Permit No.: 11-50-3769
Date of Issue: December 23, 1981
Expiration Date: November 18, 1986
Project Description: This modification extended the expiration date of the permit to November 18,
1986.
Department of the Army Corps of Engineers Permit No.: 79K-0282
Date of Issue: August 2, 1983
Expiration Date:November 18, 1986
Project Description: This was an extension of the permit authorizing the filling of 75± acres of
mangrove wetlands north, east and west of Upper Clam Bay and south of Vanderbilt Beach Road, plus
approximately 2 acres of mangroves at the existing Collier County beach access at Vanderbilt Beach
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Road. The request was reviewed and no objections were raised to the proposed work schedule;
therefore,the completion date of the permit was extended for 2 years until November 18, 1986.
South Florida Water Management Plan Modification of Surface Water Management Permit No.: 11-
00065-5
Date of Issue: December 15, 1983
Date of Expiration: Operational phase doesn't expire
Project Description: Approved modifications to 1) Revise system V, drainage area 3. 2) Construction
and operation of water management system number VI.
Department of Environmental Regulation Permit/Certification No: 110974055
Date of Issue: September 12, 1985
Expiration Date: September 11, 1987
Project Description: To construct approximately 2900 linear feet of 10' wide public access elevated
boardwalk and pier with a 6' wide navigation access lift gate in Outer Clam Bay.
Department of the Army Corps of Engineers Permit No.: 86IPT-20328
Date of Issue: December 18, 1986
Expiration Date: December 18, 1991
Project Description: Discharge+2.3 acres of clean fill to construct an access road.
Department of Environmental Regulation Modification Permit No.: 11-50-3769
Date of Issue: January 7, 1987
Expiration Date: December 18, 1991
Project Description: This permit modification extended the expiration date and reduced the amount of
fill in the area extending south along the coastal edge from approximately 13 acres, as permitted, to
2.43 acres in order to construct a linear access road(for The Strand in Bay Colony).
Department of Environmental Protection Permit/Certification No: 112659015
Date of Issue: March 14, 1995
Expiration Date: March 14, 2000
Project Description: Re-establish the connection between the Gulf of Mexico to the Clam Bay system,
by dredging from the mouth of Clam Pass and spoiling the sand over an upland beach site.
Collier County Ordinance No: 96-16
Date of Issue: April 9, 1996
Expiration Date: n/a
Project Description: To impose idle speed/no wake zones in the Clam Bay system.
Department of Environmental Protection Permit/Authorization No.:0128463-001-JC
Date of Issue: July 06, 1998
Expiration Date: July 06, 2008
Project Description: This Permit authorized activities to improve the hydrodynamics of, and thus
restore and manage,the Clam Bay ecosystem.
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Department of the Army Corps of Engineers Permit No.:199602789 (IP-CC)
Date of Issue: August 11, 1998
Expiration Date: July 08, 2008
Project Description: This Permit authorized the following works: 1) Replacement of Seagate Drive
Culverts and installation of one-way check valves on the culverts (pages 45 — 50 of the CBRMP). 2)
Clam Pass main channel dredging for Cuts 1, 2, 3 and 4 (pages 49—65 of the CBRMP). 3) Excavation
and maintenance of Interior Tidal Creeks (pages 65—71 of the CBRMP).
Department of Environmental Protection Permit Modification DEP Permit No:0128463-001-JC
Date of Issue: December 15, 1998
Expiration Date: July 06, 2008
Project Description: This permit modification authorized: 1) an alternative to upland spoil disposal
area for Cut#1; 2) an increase in the width of the channel Cut#4 through Clam Pass; and 3) alternative
pipeline corridors between the dredge cuts and the disposal areas.
Department of Environmental Protection Permit Modification for Permit No: 0128463-001-JC
Date of Issue: February 16, 1999
Expiration Date: July 6, 2008
Project Description: Authorize minor revisions to the mangrove trimming procedures pursuant to site
verification.
Department of the Army Corps of Engineers Modification for Permit No.:199602789 (IP-CC)
Date of Issue: February 26, 1999
Expiration Date: July 08, 2008
Project Description: This application requested a modification to: 1) discharge the dredge material
from Cut#1 to new disposal area identified as an upland parking area; 2) increase the width of channel
Cut #4; 3) remove native vegetation and excavate a portion of upland Disposal Site #2; 4) remove
native vegetation and excavate a portion of upland Disposal Site #3. Issues 1 & 2 were found to be
insignificant and the permit was modified. The requests regarding issues 3 & 4 were not approved at
this time.
Department of the Army Corps of Engineers Modification for Permit No.:199602789 (IP-CC)
Date of Issue: March 08, 1999
Expiration Date: July 08, 2008
Project Description: This application requested a modification to: 1) discharge the dredge material
from Cut#1 to new disposal area identified as an upland parking area; 2) increase the width of channel
Cut #4; 3) remove native vegetation and excavate a portion of upland Disposal Site #2; 4) remove
native vegetation and excavate a portion of upland Disposal Site #3. The proposed modification to
widen channel Cut #4 is to be done without any additional seagrass impacts. Based on the review and
coordination with FWS, the permit was modified in accordance with these requests.
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Department of Environmental Protection Permit Modification for Permit No: 0128463-001-JC
Date of Issue: May 19, 1999
Expiration Date: May 28, 1999
Project Description: Re-grade beach fill material during the marine turtle nesting season to remove
pockets of fine silty material and to remove an escarpment which may interfere with nesting marine
turtles.
Florida Fish and Wildlife Conservation Commission File No: 2003-0511-016BS for Permit No: CO-
016
Date of Issue: March 24, 2000
Expiration Date: n/a
Project Description: This Permit granted approval for placement of canoe trail markers in Clam Bay.
Department of the Army Corps of Engineers for Permit No: 200001076 (NW-EF)
Date of Issue: April 13, 2000
Expiration Date: February 11, 2002
Project Description: Approved the installation of 32 waterway markers for a canoe trail in the Clam
Bay system.
Department of the Army Corps of Engineers Modification for Permit No.:199602789 (IP-CC)
Date of Issue: May 05, 2000
Expiration Date: July 08, 2008
Project Description: This application requested modifications to the monitoring and reporting schedule
referenced on page 93 (Biological Monitoring) of DA Permit (CBRMP). The request was to submit
annual reports instead of semi-annual reports. The permit was modified as requested.
Department of Environmental Protection Permit for Permit No: CO-732
Date of Issue: October 25, 2002
Expiration Date: October 25, 2003
Project Description: Perform dune and beach restoration, and plant salt-tolerant native dune vegetation
in association with interim maintenance dredging event.
Department of the Army Corps of Engineers Permit No.:199602789 (IP-CC) Extension
Date of Issue: May 8, 2008
Expiration Date: July 08, 2009
Project Description: This Permit authorized the extension of the expiration date for a period of one
year.
Department of Environmental Protection Permit/Extension No. 0128463-001-JC
Date of Issue: June 5, 2008
Expiration Date: July 06, 2009
Project Description: This modification extends the expiration date for a period of one year.
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Department of Environmental Protection Permit No: 11-0128463-005
Date of Issue: December 17, 2010
Expiration Date: December 17, 2015
Project Description: Continue maintenance activities to the hand-dug channels in the Clam Bay
system originally permitted under Permit No. 0128463-001-JC.
Department of Environmental Protection Permit No: 11-0295193-004
Date of Issue: November 2, 2011
Expiration Date: November 2, 2016
Project Description: Install 32 canoe trail markers and informational signage.
Department of Environmental Protection Permit No: 0296087-001-JC
Date of Issue: August 14, 2012
Expiration Date: August 14, 2022
Project Description: Restore the alignment of Clam Pass to the previously approved location and
conducting periodic maintenance dredging of a portion of the Clam Pass Channel in order to maintain
tidal exchange between Clam Bay and the Gulf of Mexico.
United States Fish and Wildlife Service Biological Opinion Activity Code No: 41420-2010-CPA-0395
Date of Issue: February 22, 2013
Expiration Date: n/a
Project Description: FWS analysis of the potential effects of the dredging of the Pass on the threatened
piping plover (Charadrias melodus), threatened loggerhead sea turtle (Caretta caretta), endangered
Hawksbill (Eretmochelys imbricate), leatherback (Dermochelys coriacea), green (Chelonia mydas),
and Kemp's ridley (Lepidochelys kempii) sea turtles, and the endangered West Indian manatee
(Trichechus manatus).
Department of the Army Corps of Engineers Permit No: SAJ-1996-02789 (NWP-WDD)
Date of Issue: February 28, 2013
Expiration Date: March 18, 2017
Project Description: Dredging from Clam Pass and tidal creek to restore tidal exchange into Clam
Bay.
Department of Environmental Protection Permit Modification to Permit No: 0296087-002-JN
Date of Issue: March 1, 2013
Expiration Date: August 14, 2022
Project Description: Modification to re-open Clam Pass
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5.0 Management Plan Goal and Supporting Objectives
The following goal and supporting objectives for the management of the Clam Bay Natural Resource
Protection Area were developed in accordance with the directives of the Collier County Board of
County Commissioners (BCC) and the Pelican Bay Services Division, which serves as an advisory
board to the BCC. The goal and supporting objectives were formed in conjunction with stakeholder
input and are based on the management issues present in the preserve as well as the purposes for which
the land is held in public trust. The document goal and supporting objectives set forth in this plan
should not appreciably change over time but the management techniques and activities proposed may
be modified based on ongoing coordination with stakeholder and user groups or when management
objectives are not being met.
Management concerns are addressed in the following sections along with the management techniques
or activities proposed for addressing those concerns. The ability to implement specific goal objectives
presented in this plan will be based on funding and staffing availability. The following framework was
identified during the stakeholder and PBSD committee meetings.
GOAL
The goal of the Clam Bay NRPA Management Plan is to protect, preserve, maintain, and
monitor the native floral and faunal communities to ensure protection and long-term
sustainability of the natural resources by incorporating, evaluating and prioritizing all relevant
information about the estuary into a cohesive management strategy that allows for recreational
activities within its boundaries, while protecting the long-term health of the ecosystem and its
natural and historical resources.
Objectives to support this goal include:
1. Maintain and protect the native floral and faunal communities within the Clam Bay
NRPA
2. Protect archaeological sites within the Clam Bay NRPA
3. Ensure recreational activities are environmentally compatible within the Clam Bay
NRPA
4. Ensure the estuary has adequate tidal and freshwater flows to maintain ecological health
within the Clam Bay NRPA
5. Monitor, maintain, and where possible and economically feasible, enhance water quality
within the Clam Bay NRPA
These objectives were formed to allow for adaptive management, whereby the compilation and
analysis of all data will occur holistically and provide direction to adjust strategies to better achieve the
goal.
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Objective 1 - Maintain and protect the native floral and faunal communities within the Clam Bay
NRPA
A. Maintain healthy, native floral and faunal populations
i) Identify and Plan:
a. Identify flora and faunal resources to monitor
b. Establish methods for monitoring
c. Determine if a baseline study for the resource has been completed or if one is
needed
d. Define an appropriate monitoring schedule
ii) Report and Analyze:
a. Document monitoring results
b. Analyze data
c. Compare data to baseline conditions
d. Determine if anthropogenic habitat enhancements are appropriate (nest boxes,
planting, etc)
e. Determine implications on current management methods
iii) Adapt and Act:
a. Identify changes to methods to better achieve objective
b. Implement adaptions to management
B. Protect Listed Species
i) Identify and Plan:
a. Identify, locate and determine status of listed flora and fauna species and
associated habitat types
b. Identify vulnerable listed species and potential problem areas
c. Compile existing and baseline data (including population trends, potential
threats, and past incidents)
d. Establish methods for monitoring
e. Define an appropriate monitoring schedule
ii) Report and Analyze:
a. Assess listed species and compare data to baseline
b. Document threats, harassment, and/or damage
c. Analyze trends
d. Determine implications on current management methods
iii) Adapt and Act:
a. Identify changes to methods to better achieve objective
b. Implement adaptions to management
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C. Remove Exotic and Nuisance Flora and Fauna
i) Identify and Plan:
a. Identify and locate exotic, non native and nuisance species
b. Establish methods for monitoring
c. Define an appropriate monitoring schedule
ii) Report and Analyze:
a. Assess status of exotics and nuisance species
b. Track changes in type and extent
c. Determine if removal action is required
iii) Adapt and Act:
a. Remove Category I and II invasive exotic species and nuisance species (if
appropriate)
b. Identify changes to methods to better achieve objective
c. Implement adaptions to management
D. Develop an integrated resource management strategy to interpret research results and
configure modeling tools for implementing a conservation strategy
i) Identify and Plan:
a. Define a suite of indicators to detect changes in the ecosystem and response(s)
to that change
b. If appropriate, develop an ecosystem model that incorporates system drivers
ii) Report and Analyze:
a. Report and analyze model results
b. Assess biological and physical characterizations of the estuary
c. Verify model predictions with actual collected data
iii) Adapt and Act
a. Identify missing components
b. Plan future research
c. Identify changes to methods to better achieve objective
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Objective 2 -Protect archaeological sites within the Clam Bay NRPA
Develop an effective management approach to maintain and conserve known
archeological sites and their associated artifact assemblage from vandalism, exotic
vegetation, erosion and other forms of degradation
i) Identify and Plan:
a. Identify the historical studies on record with the Florida Division of Historical
Resources (DHR)that have been completed to date
b. Allow archeologists interested in conducting further investigations to do so in
conjunction with DHR
c. Establish methods for monitoring (photo stations,transects, etc.)
d. Define an appropriate monitoring schedule
ii) Report and Analyze:
a. Document monitoring results, identifying any signs of deterioration
b. Compare data to baseline conditions
iii) Adapt and Act
a. Report any new findings to DHR Master Site Files
b. Develop methods to discourage vandalism and/or disturbances (if necessary)
c. Plan future research should new technologies allow opportunities
d. Identify changes to methods to better achieve objective
e. Implement adaptions to management
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Objective 3 - Ensure recreational activities are environmentally compatible within the Clam Bay
NRPA
A. Enable the public to make informed decisions when recreating by increasing their
ability to act responsibly when enjoying the coastal community ecosystem
i) Identify and Plan:
a. Identify and locate existing permitted signage, publications and interpretive
exhibits that educate the public about the system and stewardship
b. Define an appropriate monitoring and updating schedule for permitted signage,
publications and interpretive exhibits
c. Establish methods for tracking trends of public use, law enforcement citations
and incompatible uses
ii) Report and Analyze:
a. Document monitoring and tracking results
b. Analyze data
c. Determine if any activities resulted in damage to natural resources
d. Track changes in signage permitting process and enforceability
e. Determine implications on current management methods
iii) Adapt and Act:
a. Repair or replace damaged signage
b. Update or add to existing permitted signage, publications and interpretive
exhibits (if necessary and/or able)
c. Promote and encourage traditional, low impact recreational uses
d. Identify changes to methods to better achieve objective
e. Implement adaptions to management
B. Increase active stewardship by promoting the value of coastal resources
i) Identify and Plan:
a. Catalog educational signage and printed materials
b. Identify potential partner/volunteer organizations and personnel
c. Establish methods for planning and performing volunteer efforts (including
clean-up, monitoring, educational tours, etc.)
d. Develop methods to discourage vandalism and resource disturbance
ii) Report and Analyze:
a. Document data, results, and events
b. Analyze data
c. Determine if any activities resulted in damage to natural resources
d. Track changes in signage permitting process and enforceability
e. Determine implications on current management methods
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iii) Adapt and Act:
a. Repair or replace damaged educational signage
b. Update or add to educational signage and printed materials (if necessary and/or
able)
c. Promote and encourage volunteer and partnering efforts
d. Identify changes to methods to better achieve objective
e. Implement adaptions to management
C. Maintain opportunities for low-impact public use
i) Identify and Plan:
a. Define Collier County (Parks and Rec) and PBSD upkeep responsibilities
regarding public access and areas
b. Establish methods for inspecting and maintaining public access and areas
c. Develop methods to relay public concerns, as well as issues with public access
and areas, back to Collier County (Parks and Rec) and to ensure action/follow
up
ii) Report and Analyze:
a. Document concerns and maintenance issues
b. Analyze data
iii) Adapt and Act:
a. Coordinate with Collier County (Parks and Rec)to refine interactions and doling
of responsibilities
b. Identify changes to methods to better achieve objective
c. Implement adaptions to management
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Objective 4 - Ensure the estuary has adequate tidal and freshwater flows to maintain ecological
health within the Clam Bay NRPA
A. Identify the minimum tidal flow necessary to ensure a healthy ecosystem. Provide
sufficient tidal exchange to maximize benefits while minimizing negative environmental
impacts.
i) Identify and Plan:
a. Establish adequate long-term key hydrological and biological guidelines to
sustain ecosystem health
b. Identify conditions that prompt further investigation into whether or not to
dredge Clam Pass
c. Plan for stakeholder meetings to address the need for a 10 year dredging permit
d. Establish methods for monitoring the Pass and internal waterways, including
(bathymetry,tide gauge data, and biological data)
e. Define appropriate monitoring schedules
ii) Report and Analyze:
a. Document data collected to monitor the Pass and internal waterways
b. Analyze data in conjunction with biological data to determine if any action is
necessary
1. Evaluate if dredging is necessary to prevent ecological damage to estuary
2. Determine if recent hydrologic surveys indicate significant shoaling
3. Assess the probability that the situation is unable to naturally rectify
itself
iii) Adapt and Act:
a. If action is appropriate, design and develop a dredging template with
consideration of resources
b. Attain authorization from agencies
c. Identify changes to methods to better achieve objective
d. Implement adaptions to management
B. Ensure appropriate freshwater inputs and drainage
i) Identify and Plan:
a. Determine quantity, quality and timing of adequate freshwater inputs
b. Develop methods and schedule for assessing watershed flow
c. Establish methods and schedule of assessing hand dug channels
ii) Report and Analyze:
a. Document status of hand dug channels and identify areas of impoundment
b. Assess current watershed flow and compare to data from prior years and per-
development
c. Prioritize maintenance needs within hand dug channels
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d. Determine implications on current management methods
iii) Adapt and Act:
a. If needed, conduct prioritized maintenance on hand dug channels
b. Attain necessary authorization from agencies
c. Identify changes to methods to better achieve objective
d. Implement adaptions to management
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Ver.4.2
Objective 5 - To restore, enhance and maintain with water quality within the Clam Bay NRPA
A. Develop a long-term water quality program that assesses physical, chemical and
biological processes to ensure a sustainable healthy environment for all users
i) Identify and Plan:
a. Establish a water quality monitoring program that incorporates historical data to
assess water quality
b. Ensure that this program complies with FDEP guidelines and standards,
addresses the Site Specific Criteria previously approved by the State, and
complies with Objectives 4 and 5
c. Continue monthly water quality sampling in accordance with FDEP Standard
Operating Procedures
d. Develop a plan to track the quality of freshwater and saltwater inputs within the
watershed
e. Explore partnership opportunities to address water quality concerns
ii) Report and Analyze:
a. Complete quarterly reports detailing water quality data
b. Assess results and compare to past data
c. Assess results in conjunction with biological data
d. Determine if any parameters are outside of tolerances or presenting trends
e. Determine probable cause if deterioration occurs
iii) Adapt and Act:
a. Develop and enact solutions to restore healthy water quality
b. Identify changes to methods to better achieve objective
c. Implement adaptions to management
B. Promote comprehensive programs for controlling water pollution from point and
nonpoint sources
i) Identify and Plan:
a. Determine how and to what degree water quality within the Clam Bay NRPA is
influenced by land use (including hydrologic restoration)
b. Identify best management practices geared at reducing storm water pollutant
loads
c. Continue with plan to reduce or eliminate Copper Sulfate usage within Pelican
Bay storm water lakes
ii) Report and Analyze:
a. Assess monthly water quality sampling results
b. Assess upland stormwater sampling results when available
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c. Analyze data to determine if efforts have resulted in a reduction in nutrient
and/or pollution parameters of freshwater inputs
iii) Adapt and Act:
a. Refine strategies to achieve both reduction of nutrients and pollutants and to
achieve compliance with FDEP standards
b. Implement adaptions to management
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Ver.4.2
Clam Bay NRPA Management Plan Amendments
Studies within the Clam Bay Estuary as well as in other similar local ecosystems are either ongoing or
expected to occur within the asked for time frame of this document. The Management Plan is not
expected to be a static document and ongoing research and data collection related to water quality;
hydrographic changes in the various areas of the system; benthic community health; mangrove
community health; exotic and nuisance vegetation control; and public education will be conducted
and/or collected. Conclusions, recommendations, or alternative management activities that come about
as a result of studies conducted outside of the scope of this management plan will be examined and
considered by the Pelican Bay Services Division and its consultants. Those modification that are
found to be viable,pertinent, and economically feasible alternatives or additions allowed under the
scope of this plan will be added to the plan. Those changes in management activities or new work
items that are outside of the scope of the Plan but are considered important or practicable by the
Pelican Bay Services Division and its consultants will be submitted to DEP and the ACOE for
consideration and inclusion into this Management Plan.
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March 18,2014
Ver.4.2
Clam Bay NRPA Management Plan Bibliography
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2. Tri-County Engineering, Inc., 1971, Tidal Datum Plane Determination for the Collier
Company.
3. Davis, R.A. Jr., Gibeaut, James C., 1990, Historical Morphodynamics of Inlets in Florida:
Models for Coastal Zone Planning, Technical Paper.
4. Department of Coastal and Oceanographic Engineering, Florida Engineering and Industrial
Experiment Station, University of Florida, 1970, Proposed Navigation Entrance to Clam Bay
on Marco Island, Collier County, Marco Island Development Corporation,technical paper.
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Associates, Inc.,technical paper.
6. Devlin, Donna J., Gore, Robert H., Proffitt, C. Edward, 1987, Preliminary Analyses of Seagrass
and Benthic Infauna in Johnson and Clam Bays, Collier County, Florida,Natural Resources of
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8. Heald, Eric J., Tabb, Durbin C., Roessler, Martin A., Beardsley, Gary L., Ward, Gerlad M.,
Durrance, Dallas H., Yeend, John S., 1978, Carbon Flows in Portions of the Clam Pass
Estuarine System, Collier County, Florida, Tropical Biolndustries Company and Gee and
Jenson, Engineers-Architects-Planners, Inc.,technical paper.
9. 1994, Clam Bay Natural Resources Protection Area Management Plan Draft, Collier County
Natural Resources Department,technical paper.
10. Worley, Kathy, Hennig, Markus, July 2000, Clam Bay Mangrove Projects: Interim Summary
of Statistical Results, The Conservancy of Southwest Florida, technical paper.
11. Benedict, Mark A., Harvey, Judson W., Curran, Maura E., 1983, Part 1 Beach Management
Planning and Implementation Strategies at the Local Level,Natural Resources of Collier
County Florida, technical paper.
12. Benedict, Mark A., Harvey, Judson W., Curran, Maura E., 1983, Part II The Beach in Collier
County: A Model in Southwest Florida,Natural Resources of Collier County Florida,technical
paper.
81
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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Ver.4.2
13. Benedict, Mark A., Harvey, Judson W., Curran, Maura E., 1983, Part 3 A Resource
Management Program for the Coastal Barriers of Collier County Florida,Natural Resources of
Collier County Florida,technical paper.
14. October 1990, Collier County Sand Source and Environmental Report Phase II Hard Bottom
Characterization, Continental Shelf Associates, Inc.,technical paper.
15. Hartwell, Richard W., Hatcher, James M., Grabe, Stephen, August 1994, Clam Bay Natural
Resources Protection Area (NRPA), Collier County Environmental Services Division,
Publication Series NR-SP-94-01,technical paper.
16. Dean, R.G., O'Brien, M.P., December 1987, Florida's West Coast Inlets Shoreline Effects and
Recommended Action, Coastal and Oceanographic Engineering Department and Division of
Beaches and Shores Department of Natural Resources, technical paper.
17. Heald, E.J., Roessler M.A., Beardsley, G.L., 1979, Litter production in a Southwest Florida
Black Mangrove Community, Reprint from Proceedings of the Florida Anti-Mosquito
Association 50th Meeting, Abstract.
18. May 1970, Coastal Engineering Study of the Proposed Clam Pass Improvement, The Collier
Company, Department of Coastal and Oceanographic Engineering,technical paper.
19. Sarkar, Chiranjib K., October 1972, Hydrographic Investigation of the Clam Bay System, Tri-
County Engineering, Inc., Technical paper.
20. June 1979, A Comparative Study of the Water and Carbon Flows of Upper Clam Bay, Tropical
BioIndustries and Missimer and Associates, Inc.,technical paper.
21. Heald, Eric J., Roessler, Martin A., December 1979, Invertebrate Population Studies in the
Vicinity of Upper Clam Bay, Collier County, Florida, Tropical BioIndustries, technical paper.
22. Heald, Eric J., July 1983, Populations of Melampus coffeus and Cerithidea scalariformis West
of Upper Clam Bay, Collier County, Florida, Tropical BioIndustries, Inc.,technical paper.
23. Heald, Eric J., July 1983, Fish Populations of Tidal Ponds West of Upper Clam Bay Collier
County, Florida, Tropical BioIndustries, technical report.
24. Crewz, David W., 1989, Clam Pass Park mangrove damage, Department of Natural Resources
Interoffice Memorandum.
25. Wanless, Harold R., Risi, J. Andrew, July 1996, Observations on Barrier Beach Stratigraphy
and Groundwater Flow in the Vicinity of the Mangrove Die Off Adjacent to the Strand, Pelican
Bay, Collier County, Florida, Collier County Natural Resources Department,technical report.
26. Wanless, Harold R., February 1975, Report on the Beaches of Naples, Florida,technical report.
82
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
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Ver.4.2
27. Hawkins, Mary Ellen, Obley, Ross P., "Pelican Bay-Visit and Revisit." Urban Land Vol. 40,
No 11., (December 1981) 21-27.
28. Lorenz, William, D. Jr., January 1996, Clam Bay NRPA Nutrient Reduction Program Draft,
technical report.
29. Scott, Will, December 1993, "Water, Water...Everywhere what you may not know about
Pelican Bay's innovative water management system."Draft- memorandum, ABB.
30. Heald, Eric J., January 1972, Investigation of Fluctuations in the Clam Bay System, Tri-County
Engineering, Inc and Tropical Biolndustries,technical report.
31. Acquaviva, Daniel J., October 1993, Responses to Development of Regional Impact Questions
Number 14 and 17 Pelican Marsh Community,North Naples, Florida, ViroGroup
Inc./Missimer Division,technical paper.
32. Davis, Richard A Jr., Gibeaut, James, January 1990, Historical Morphodynamics of Inlets in
Florida: Models for Coastal Zone Planning. Department of Geology, University of South
Florida, technical report.
33. Knapp, Michael S., Burns, Wm. Scott, Sharp, Timothy S. Preliminary Assessment of the
Groundwater Resources of Western Collier County, Florida. Technical publication#86-1.
February 1986.
34. "Modification of Permit No. 11-00065-S Pelican Bay." Pelican Bay Improvement District Staff
Report. March 1983.
35. Preliminary Hydrographic Assessment Clam Bay Systems. Tackney &Associates, Inc.,August
1996.
36. Hole, Montes & Associates, Inc., Post, Buckley, Schuh & Jernigan, Inc. Water Management
Plan Construction Permit Application for Systems 4 and 5. Pelican Bay Improvement District,
September 1982.
37. Goodrick, Robert L. "Pelican Bay—Environmental Considerations,permit No. 11-00065-S."
Memorandum to file, January 15, 1982.
38. Hermanson, George H. "Proposed Modifications to Drainage Area 3, System No. V." Hole,
Montes& Associates, Inc., January 28, 1988.
39. "Modification of Permit No. 11-00065-S Pelican Bay." Pelican Bay Improvement District Staff
Report, 1983.
83
CLAM BAY NRPA MANAGEMENT PLAN(DRAFT)
Pelican Bay Services Division
March 18,2014
Ver.4.2
40. Florida. South Florida Water Management District. In Reply to Request for Modification of
Surface Water Management Permit No. 11-00065-S." October 19, 1978.
41. Stanley W. Hole and Associates, Inc., Post, Buckley, Schuh & Jernigan, Inc. Water
Management Plan Permit Application. Pelican bay Improvement District, April 1978.
42. Florida. Collier County Environmental Services Division Inlet Management Resources.
Bibliography.
43. Florida. South Florida Water Management District. Application No. 04718-C for Surface Water
Management Permit Staff Report. August 1978.
44. Post, Buckley, Schuh &Jernigan, Inc. Consulting Engineers and Planners. Engineering Report
Water Management System VI for the Pelican Bay Improvement District. February 1984.
45. Wilson, Miller, Barton &Peek, Inc. Pelican Bay/Clam Bay Water Management System
Contributing Areas. CAD drawings. October 1998.
46. Coral Ridge-Collier Properties, Inc. Pelican Bay A Planned Residential Community.
47. Florida. Natural Resources of Collier County Florida. Part 5 Coastal Zone Management Units:
Atlas. 1984.
48. Suboceanic Consultants Inc.Naples Beach Study Report. University of Florida Coastal
Engineering Archives. August 1980.
49. Wilson, Miller, Barton&Peek, Inc. Pelican Bay Mangrove Investigation, Pelican Bay Water
Management System-Stormwater Detention Volume and Water Budget Analyses. April 1996.
50. Continental Shelf Associates, Inc. Collier County Sand Source and Environmental Report
Phase I Hard Bottom Mapping. Coastal Engineering Consultants, Inc, October 1990.
51. Collier County Pelican Bay Services Division. Clam Bay Restoration and Management Plan.
Florida Environmental Resource and Joint Coastal Permit Application, Federal Dredge and Fill
permit Application. April 1997.
52. Missimer and Associates, Inc. Subsurface Water and Carbon Floes to Portions of the Clam Pass
Estuarine System, Collier County, Florida. Technical report, March 1979.
53. The Collier Company. Coastal Engineering Study of the Proposed Clam Pass Improvement.
Engineering and Industrial Experiment Station, College of Engineering, University of Florida.
May 1970.
54. Crewz, David W. Florida. Department of Natural Resources. Clam Pass Mangrove Damage.
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84
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March 18,2014
Ver.4.2
55. Wilson, Miller, Barton &peek, Inc. Figure 1 Existing Stormwater Flows on an Outgoing Tide
(Diagrammatic). Map of Clam Bay.
56. Wilson, Miller, Barton&Peek, Inc. Figure 2 Proposed Expedited Conveyance Plan of
Stormwater Flows on an Outgoing Tide (Diagrammatic). Map of Clam Bay.
57. Acquaviva, Daniel J. Site Specific Investigations to Obtain Hydrologic Information for the
Design of Horizontal Well Systems at Pelican Bay,Naples, Florida. Water Resource Solutions,
Inc., September 1999.
58. Hole, Montes & Associates, Inc. "Evaluation of an Onsite Irrigation Water Source." The
Pelican Bay Improvement District, April 1984.
59. Post, Buckley, Schuh & Jernigan, Inc. Hydrology and Geology of a Proposed New Well Field
Site in North Collier, Florida. For the Pelican Bay Improvement District, March 1978.
60. Obley, Ross P., letter to Jim Ward. July 1999.
61. Gee & Jenson Engineers,Architects & Planners, Inc. "Pelican bay System VI Drainage."April
1983.
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63. Florida. "Aquatic Plant Management Annual Operations Report." Florida Department of
Environmental Protection Bureau of Aquatic Plant Management. January 1999.
64. Florida. "Agreement for Delivery and use of Treated Wastewater Effluent for Spray Irrigation."
Official record of Collier County, Florida. Interoffice Memo. August 1996.
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January 1999.
66. Davis, Richard A., Hine, Albert C., Bland, Michael J. "Midnight Pass, Florida: Inlet Instability
Due to Man-Related Activities in Little Sarasota Bay." Coastal Sediments `87, May 1987.
67. Metz, Charles. "More than Mangroves at Stake."April 1997.
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Water Management Permit No. 11-00065-S." Staff Report. October 1978.
69. Florida. South Florida Water Management District. "Water Use Permit." June 1998.
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70. Hartman, P.K. "Excavation Permit No. 59.156." Collier County Water Management
Department letter, March 1983.
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Groundwater Monitoring." Department of Environmental Regulation, State of Florida, letter.
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Summary."April 1992.
86
Appendix 1
Recent History of Mangrove Management in Clam Bay
According to detailed field surveys performed in the early 1970's mangrove tree
densities within the Clam Bay NRPA ranged from 726 to 7,580 per acre and
maximum canopy height was 39 feet. Within the black mangrove dominated basin
forest west of Upper Clam Bay, 16% of the black mangrove trees were reported as
dead and others as severely stressed; evidenced by a high incidence of dead limbs on
trees of all sizes (Tropical Biolndustries and Gee and Jenson, 1978).
Dead and stressed mangroves were again reported for Clam Bay in 1989 when David
W. Crewz, a biologist with the Florida Marine Research Institute, was asked to
inspect Clam Pass Park by Mary Ellen Hawkins,then a Collier County representative
to the legislature (letter to Don Duden dated April 3, 1989). Mr. Crewz concluded
that the "dead and stressed mangroves were caused by lack of adequate water
circulation resulting from the closure of Clam Pass.... allowing toxin and salt
buildup."
Westinghouse Consultants, Inc., employees in February 1992 noted additional
mangrove die-offs, north of Clam Pass Park on the west side of Upper Clam Bay.
This area was inspected by Dr. Eric Heald, a consultant to WCI, and reported to WCI
in April 1992, as probably due to hypersalinity, although 1991 was an above average
rainfall year. The same conclusion was reached by Robin Lewis of Lewis
Environmental Services, Inc., after an inspection in May 1994. At this time the die-
off area was approximately 6 acres. A widespread mortality of mangroves in Florida
Bay was also reported in the summer of 1991 (Yarboro et al. 1994) and it was
attributed, in part, to natural drought conditions and unusual tidal inundation
patterns.
After above average rainfall in the summer of 1995, The Conservancy, Inc.'s staff
and residents in Pelican Bay reported additional mangrove deaths which continued
through 1995 and 1996. The total area of the die-off through July 1999 was around
50 acres.
The death of trees occurred around hyper saline ponds and is consistent with conditions
caused by periods of excessive inundation of freshwater followed by periods of
continuous dry down, particularly where the mechanism for flushing is impaired. (Lugo,
et. al. 1976). During the period immediately preceding the observed die off, and during
the periods following, Clam Bay received record amounts of rainfall. This rainfall, when
combined with an admittedly impaired circulation system, encroaching development of
the Strand community to the west, and intermittent pass closure, resulted in water levels
that were high enough for a long enough period of time to adversely impact the
mangroves (CBRMP 1998).
The Clam Bay Restoration and Management Plan was finalized in 1998 to address the
mangrove die-off. In assessing a variety of alternatives to the restoration of Clam Bay,
the original need was not so much to restore the system to a mangrove forest (although
that remained the primary goal) as it was to stabilize and restore the system as a thriving
natural resource. This was accomplished through the dredging of Clam Pass and portions
of the interior channels within the system, as well as construction of a network of hand-
dug flushing channels throughout the original die-off area and a few other areas that were
exhibiting stress. It was recognized that with changes to naturally induced flushing rates
and hydrological regimes the mangroves would likely adjust by altering zonation
patterns, species compositions, rates of growth and mortality, etc. (CBRMP 1998).
Summary of annual monitoring since the implementation of the CBRMP
Provided below is a brief, annual summary of the overall health of the Clam Bay
mangrove system. This recent history of the mangrove management spans from 1999 to
2013. These summaries include key events, such as major weather occurrences, flushing
channel construction and maintenance, as well as documentation of areas of improvement
and calculations of die-off acreages.
1999
A total estimate of 42.67 acres dead or stressed mangroves was provided by Turrell, Hall
& Associates, Inc. consisting of the main basin area adjacent to The Strand and several,
smaller, discrete areas possibly attributed to lightning strikes or where slight depressional
areas allow ponding and salinity/oxygen stress. Little change was noted later in the
summer at the time-zero survey although most mangrove plots showed significant
standing water which could be a function of the dredging work as well as tides and rains
around the survey time.
The main die-off area(NW Clam Bay, adjacent to The Strand) 1999
2000
A full year after the dredging work, no dramatic changes were apparent, some mangrove
plots had declined; others appeared in slightly better health. Seedling recruitment was
good throughout. Heavy rains in late 1999 were thought to have contributed to a dieback
in groundcover noted by Lewis Environmental Services. No new mangrove die-offs or
expansion of stressed areas were noted. Work planned for 2001 included the
experimental Riley encasement method for mangrove propagules.
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2001
Mapping of the die-off area was repeated and estimated to have increased in size,
spreading to the north, to encompass just under 50 acres. Additionally a few new
stressed areas were identified through aerial photographs. Individual plots showed some
additional tree losses but consistent seedling recruitment. Channel construction in the
main die-off area and close to Plot 7 is thought to have contributed to the recovery
process underway, illustrated by extensive Batis and dramatic seedling recruitment.
The observations generated sufficient concern amongst project managers in 2001 that a
suggestion for additional flushing channel construction in the die off area was made.
4,<
Main die-off area 2001
2002
Additional flushing channels were constructed in the die-off area during late 2001 and
results from the 2002 surveys show that these efforts appeared to have been successful
with a reduction of 12 acres made in the die-off area. Batis growth and seedling
recruitment was good. The problem of exotic vegetation growth in many areas was
highlighted and two new diffuse areas of stressed trees were identified. The presence of
standing water and bacterial mats suggested lack of flushing was responsible. The one-
way culverts installed at Seagate, thought to have reduced tidal exchange in Outer Clam
Bay, were removed in October to determine whether tidal exchange between Venetian
Lagoon and Outer Clam Bay could be achieved without affecting Clam Pass.
Main die-off area 2002 with notable re-growth
•
2003
Stressed areas identified in 2002 were revisited and no changes were noted in 2003. One
of the aerially depicted mangrove stress locations was found, upon groundtruthing, to
actually be an infestation of exotic plant species. Of significance is a reduction in
calculated die-off area to just over 17 acres total with 14 acres in this main die-off region,
now classified as recovering.
a
Main die-off area 2003
2004
Die-off acreage was estimated at 18 acres total in.2004, with the addition of a new area
adjacent to the Contessa condominium building n Bay Colony and several new small
lightning strike areas throughout the system. Plot 7 continues to show the most-Ler,
ost dramatic
change of mangrove plots where most exhibit slow change in existing tree number, some
losses, some growth and size-class change, but consistent seedling recruitment. Storm
events in 2004 (Charlie, Frances, Ivan, and Jeanne) had minimal effects with some leaf
loss and limb breakage. Additional flushing channels were constructed during dry season
of this year. Water level monitors put in place last year were removed due to repeated
equipment failures.
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Main die-off area 2004
2005
Several stressed areas were noted as recovering this year including that adjacent to the
Contessa building where a drainage channel was in need of maintenance and clearing,
work which alleviated the problems. A new die-off area was identified near the County
boardwalk and it is suggested that clogging of channels due to Hurricane Charley may be
responsible. Total die-off acreage in 2005 is estimated at 24.7 acres. Plot 7 and Plot 8
continue to show significant re-growth.
Hurricane Wilma in October of 2005 caused considerable leaf loss, limb breakage and
leaf browning throughout Clam Bay although the constructed flushing channels alleviated
extensive ponding that could have occurred and the system weathered the storm well.
Work completed in 2005 included the last component in flushing channel construction.
In total, approximately 13 miles worth of had-dug channels has been installed since 1999.
1
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Main die-off area 2005
2006
Stress damage from the 2005 hurricane season necessitated the need for a division of the
classification system currently used to define the status of the mangroves in the system.
Stressed mangrove zones are now classified as "die-off area" for mangroves stressed by
some factor other than storm events or"area of concern"for mangroves stressed by storm
events. It was estimated in 2006 there were 23 acres of recovery, 12.3 acres of stressed
areas of concern and 23.4 acres of die-off area present, bringing the total area of stressed
mangroves to 74.7 acres. Since the last mangrove channels were dug in 2004 and
dredging work continues when needed, most of the monitoring plots have shown
improvements and there has been a significant reduction of die-off in the original locale.
Main die-off area 2006
2007
The storm damage of 2005 added a level of difficulty to subsequent classification of areas
within the system. Extensive defoliation and falling of individual trees meant that areas
that could be termed stressed by the flow issues thought to have been responsible for the
original die-off in Clam Bay were in fact affected by the high winds and storm surge.
Approximately 4.9 acres of formerly classified 'die off area have been reclassified to
`recovered' this year. Stressed areas of concern that are likely not related to storm
damage total about 15 acres while areas of concern that we suspect are due to the storm
events have been estimated at about 25 acres. An additional 20 acres within the original
die off area has not yet fully recovered and so is also included in this category. A total of
10.6 acres of mangroves are still considered dead, a significant reduction from the
original die-off of over 50 acres in the late 1990's. This brings the total aerial estimate of
mangroves that are not at optimum health to about 70 acres.
Main die-off area 2007
2008
The 2008 monitoring report was the final report associated with the original 1998
restoration permits. Effects of the storms form 2005 still added a level of difficulty to the
classification of areas within the system. While the defoliation associated with the storms
had mostly recovered, falling debris affected several of the monitoring plots throughout
the system.
Approximately 35.4 acres of forest area have been removed from the die-off
classification since the implementation of the project. Stressed areas of concern that may
still be related to storm damage total or may be due to other factors (such as ponding or
drying) add up to about 7.1 acres. Areas throughout the system that have not yet fully
recovered but that have flushing channels and have shown marked increases in mangrove
recruitment and new growth have been removed from this category (approx. 20 acres).
A total of 7.3 acres of mangroves are still considered dead. This includes three main
areas, the initial die-off area east of the strand where there are about 5.5 acres still dead,
the damage from a tornado in the extreme north of the system accounts for about 0.8
acres, and the Hurricane Charley damage that resulted in a tidal restriction just south of
the Pass accounts for about 0.75 acres. Several lightening strikes and small discrete die-
offs spread throughout the estuary make up the remainder of the die-off acreage.
}
East of the Strand Die-off area, 2008
2010
Even though the permit requirement for monitoring reports ended with the expiration of
the 1998 permits, the PBSD continued to monitor the mangrove health within Clam Bay
and document the positive results within the mangrove forest. Exotic eradication
activities were also continued to allow for natural regeneration of mangroves observed
elsewhere in the system.
Construction of the last component of the flushing channels was completed in the 2005-
06 season. Inspection of these flushing cuts this year showed that they are still operating
as designed and are contributing to the continued growth of'new mangroves within the
system.
Stress in mangrove forest areas is still apparent, although in several areas this may still be
attributable to storm damage or to frost damage brought about by a couple of'very cold
temperature nights. The spectacular recruitment of white mangrove seedlings, now 8 to
10 feet tall saplings, throughout the original die-off area is testament to the efforts
undertaken with the initial dredging and that work can be considered a success.
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Main die-off area 2010
2011 -2012
An infestation of boring beetles was discovered in the early months of 2011.
Observations within the system and research into the life habits of many boring
beetles led to the conclusion that white mangroves stressed by the sustained cold
temperatures in December 2010 and January 2011 were most susceptible to the beetle
attack. Cold stress reduced the abilities of these trees to fight off the boring activities
and many trees succumbed to them. Yellowing leaves, leaf drop, and eventual death
of the tree was the result. The dead trees were easily visible in the rooftop photos
taken periodically from the Grosvenor and Montenero condominiums. Efforts to
hatch beetle larva led to the identification of at least two species, a round-headed
(Longhorned beetles) and aflat-headed borer (Metallic beetles). No further loss of
trees was documented after 2012 as a result of the borers.
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2013
The lack of harsh weather occurrences, hurricanes or freezing temperatures over the past
year seems to have allowed the areas impacted by the boring beetles to begin to recover.
A total of 4.02 acres of mangroves are still considered dead or stressed, ai significant
reduction from the original die-off of over 50 acres in the late 1990's. Fypical flushing
channel maintenance was conducted to ensure that the channels were operating as
designed and continue contributing to the growth of new mangroves within the system.
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Main die-off area 2013
Appendix 2
Recent History of Seagrass presence in Clam Bay
Reports of field surveys from the early to mid 1970's document the presence of
seagrasses within the Clam Bay NRPA but do not give any estimation of coverage or
densities within the system. It is noted that seagrasses are present only in Outer
Clam Bay and there is some hypothesizing that the lack of seagrasses in Inner and
Upper Clam Bays is the result of lower salinity levels and lack of water exchange
with the Gulf. (Heald, 1972, Tropical BioIndustries and Gee and Jenson, 1978).
The Collier County Department of Natural Resources produced undertook an
analysis of the seagrasses and benthic infauna in Clam Bay in 1987. In this report it
is stated that a 15m x 15m plot encompassed most of the grass beds in Clam Bay.
The report exhibits show the plot location on the east side of the waterway between
the Pass and Outer Clam Bay, much in the same location of seagrass beds which
exist today.
A DNR memorandum produced by David Crews in 1989 also mentions "some
seagrass and algal beds" being present in Outer Clam Bay but again offers no
information on location, aerial extent, or densities.
The 1991 Collier County Seagrass Protection Plan states that "Outer Clam Bay contains
one of the densest and most extensive seagrass beds in Collier County." though it does
not quantify aerial extent or density within the report. An exhibit associated with the
report shows the entirety of Outer Clam Bay from the Pass to the Seagate culverts as
seagrasses (almost 60 acres).
A 1994 report documenting conditions in the proposed Clam Bay Natural Resources
Protection Area by the Collier County Environmental Services Division documented that
seagrass coverage in Outer Clam Bay was approximately 10 acres.
Based on anecdotal information and on comparisons with other seagrass areas in the
County during the same time frame, it is not presumed probable that there was an 80%
decline in seagrass coverage during those two years but instead the 1992 report may have
over-estimated the coverage.
In 2007, PBS&J conducted a seagrass assessment in Outer Clam Bay for the Collier
County Coastal Zone Management Department. Of the 30 randomly selected sampling
sites observed, seagrasses were found in 13 of them. No conversion to an acreage
estimate was made in this report. At the locations where seagrasses were observed, the
estimated density relative to bottom coverage was between 5 and 25 percent.
•
Annual Estimates of Seagrass Coverage since implementation of CBRMP
The following annual summaries provide general observations of the presence of
seagrasses within Outer Clam Bay since the implementation of the Clam Bay Restoration
and Management Plan.
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1999
Prior to the initial dredging associated with the 1998 restoration and Management Plan,
seagrass acreage is estimated at 5.13 acres, restricted to Outer Clam Bay and the channel
leading to Clam Pass.
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1999 Seagrass Coverage
2000—2004
Seagrasses show a slow decline during this time frame. Water quality testing within the
system does not indicate chronic degradation. The decline is attributed to the increased
tidal range caused by the dredging work, which results in longer exposure at low tides of
the shallow areas where seagrasses were present. The one-way culverts installed at
Seagate, thought to have reduced tidal exchange in Outer Clam Bay, were removed in
October 2002 to determine whether tidal exchange between Venetian Lagoon and Outer
Clam Bay could be achieved without affecting Clam Pass. Seagrass bed in southernmost
portion of Outer Clam Begins to expand in 2003 after removal of flap gates.
c
2005
An increase in the seagrass coverage within the channel transects was documented.
Increased density of the beds within the bay area east of Clam Pass is also noted.
2006
Shoalgrass patches are still present in ecologically significant densities within the
channel north of the County boardwalk and just inside Clam Pass mouth. Sea grass beds
in Outer Clam Bay are still reduced compared to the 1999 pre-dredge conditions, but
their steady improvement since 2004 seems to have continued into 2006. Approximately
3.6 acres of seagrasses are noted along the transects.
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2006 Seagrass Coverage
2007
Concerns related to the seagrass coverage within the bay were raised by adjacent property
owners this year and Collier County contracted an additional study by Post, Buckley,
Schuh, & Jernigan Inc. (PBS&J) to investigate seagrasses and nutrient inputs within not
only the Clam Bay System but also Venetian Bay, Moorings Bay and the entire Doctors
Pass area.
Some of the results of the PBS&J study relevant to the Clam Bay System were;
• That seagrasses were present within Outer Clam Bay. Paddle Grass (Halophila
engelmannii) was observed at 13 of the 30 randomly generated points within
Outer Clam Bay.
• That resident's concerns that seagrass coverage had declined from 60+ acres to
present were unfounded as early estimates of 60+acres were likely erroneous.
• That nutrient and chlorophyll-a levels within Outer Clam Bay, had increased over
the past 20 years but were still below median values for Florida estuaries.
Also as a result of these increased concerns regarding seagrasses, Turrell, Hall &
Associates expanded the annual seagrass survey to cover the entire bay and not just the
defined transects. Additional seagrass beds and macroalgae were observed in areas were
they had not previously been documented. Though all of THA observations were of
shoal grass, it was noted that all of the PBS&J observations were of paddle grass. It has
been observed in the past that paddle grass is very ephemeral in this system and it is
likely that the 2 months between the PBS&J and the THA surveys was enough time for
the paddle grass to disappear.
2008
This was the final monitoring event of the seagrasses associated with the 1998
Restoration and Management Plan permits.
Increases in seagrass coverage that were noted in 2007 continued through this year. A
small area of paddle grass was observed along Transect #2 which had been devoid of
grasses in the past. Other transect areas that have been devoid of grasses until this year
include the western shoreline of the channel between Clam Pass and Outer Clam Bay
(Transect 5). Seagrasses had been present along this area prior to the dredging but were
replaced by black mangrove propagules when the increased tidal range led to extended
drying times of the shoals where the grasses had been located. New grasses this year
have been observed along the edges of the channel in areas that do not dry out so much
during low tides.
In addition to the seagrasses, other observation made along transects indicate that the
biological diversity of the macro-invertebrate fauna within the system has increased.
4
Several mollusk species including Florida horse conchs, southern hard clams, stiff pen
shells,tulip snails, cockles, oysters, and several others were all observed.
2012
Seagrass coverage within Outer Clam Bay has continued to increase. The initial decline
noted immediately following the initial (1999) dredging activities appears to have been
reverse over the past 8 years. The decrease stabilized around 2004 and has reversed in the
past few years to where the grass beds are re-establishing previous areas and new areas
appropriate for the grasses (in terms of water depths and light penetration) are being
colonized. Approximately 4.27 acres of seagrasses were noted within the system this
year. Most of the seagrass observed was shoal grass though small patches of paddle grass
and turtle grass were also observed. Future monitoring of the seagrasses will be
conducted to see if this trend continues.
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2012 Seagrass Coverage
2013
Seagrass coverage overall totaled
within the Clam Bay system, approximatel
y is than there what has been shown b acreshalong the monitored transeng
initial t(1999 was a decrease in the Y the
ets
dred in monitored seagrass bedsatthirteen
2005 and has reversed ctn the1es. This years monitoring
decrease a immediately followin
previous areas andpast few years toears to have stabilized around 2004orlight new areas appropriate for the where the grass beds are re-establishing
conducted tor see if this bend eing colonized.
grasses (in terms of Fater depths and
continues. Future monitoring of the seagrasses
will be
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2013 Seagrass Coverage
March 18,2014 Clam Bay Committee of the Pelican Bay Services Division
Submitted by Susan O'Brien
Suggested timeline for 2014 Clam Bay NRPA Management Plan and ten-year
dredging permit application
April 8 Committee meeting to put final touches on Tim's portion of the
management plan and to discuss engineering-related parts of plan
Mid-April Distribute letter to area stakeholders re: May 1 availability of
Management Plan for review and comment; and invitation to attend
Clam Bay Committee meeting on May 6 to discuss Management Plan.
(Need to decide who will distribute letter and whether hard
copies will be made available to those requesting same.)
Mid-April Article in PB Post re: May 1 availability of Management Plan for
review and comment; and Clam Bay Committee meeting on May 13 to
discuss Management Plan. (Committee may prefer to have one
meeting for both area stakeholders and PB members.)
April 22 Committee meeting to put final touches on engineering-related parts
of plan
April/May Prepare ten-year dredging permit application and appropriate
attachments for USACE and modifications to FDEP permit.
May 1 Put draft of Management Plan on website
May 6 Committee meeting for area stakeholders
May 7 Preview Management plan and permit application for PBSD Board
members
May 13 Committee meeting for interested PB members
May 16 Deadline for receiving comments on Management Plan
May 20 Committee meeting, if necessary, to discuss/address comments from
stakeholders
Late-May Finalize Management Plan and ten-year permit applications
June 4 Present to PBSD Board
June 10 Present to BCC
Mid-June File permit applications
March 18,2014 Clam Bay Committee of the Pelican Bay Services Division
Submitted by Susan O'Brien
Possible new reports/activities for Clam Bay for FY 2015
Inspect archeological sites $ 750
Monitor gopher tortoise burrows 3750
Conduct bird survey 2500
Monitor plots in scrub and hammock habitats 6000
Inspect canoe trail and Clam Bay signage 300
Monitor upland activities that could affect flow 600
Promote educational information re: exotic and nuisance species 700
Monitor sea turtle nesting 500
Coordinate with Collier County and Waldorf
re: vegetation and litter control 1000
Bathymetric survey of Clam Pass (annual)
Bathymetric survey of interconnecting waterways (initial)
March 18,2014 Clam Bay Committee of the Pelican Bay Services Division
Submitted by Susan O'Brien
CLAM BAY UPDATE (Draft for Mid-April PB Post with March 21 due date)
Clam Bay Management Plan
A draft of the 2014 Clam Bay NRPA Management Plan will be available at
PelicanBayServicesDivision.net on May 1, 2014. Interested parties are encouraged to review the
Management Plan and send their comments to Iresnick @colliergov.net by May 16 and/or attend the Clam
Bay Committee meeting on May 13, 2014,at which the document will be discussed.
The Pelican Bay Services Division's Clam Bay Committee developed the plan over the past year with the
assistance of consultants Tim Hall of Turrell,Hall&Associates and Mohamed Dabees of Humiston&
Moore Engineers and input from many area stakeholders. Members of the Clam Bay Committee are Joe
Chicurel, Tom Cravens,John Domenie,Mike Levy,and Susan O'Brien, Chairperson.
The major goal of the 2014 Clam Bay NRPA Management Plan is to protect,preserve,maintain, and
monitor the native floral and fauna communities to ensure their natural resource protection and long-term
sustainability by incorporating, evaluating, and prioritizing all relevant information about the estuary into
a cohesive management strategy that allows for recreational activities within its boundaries while
protecting the long-term health of the ecosystem and its natural and historical resources.
The objectives to support this goal include the following:
• Maintain and protect the native floral and faunal communities in Clam Bay
• Protect archaeological sites within Clam Bay
• Ensure recreational activities are environmentally compatible within Clam Bay
• Ensure the estuary has adequate tidal and freshwater flows to maintain ecological health within
Clam Bay
• Monitor,maintain and where possible and economically feasible enhance water quality in Clam
Bay
The Clam Bay Committee will recommend the final draft of the 2014 Clam Bay NRPA Management Plan
to the PBSD Board at its meeting on June 4 and ask that the PBSD Board recommend its adoption to the
Board of County Commissioners at its meeting on June 10.
The Committee is also working with the consultants on the application for a ten-year dredging permit that
will also be subject to the approval of the PBSD Board and the BCC before its submittal to the regulatory
agencies.
Clam Pass
The six-month post-dredging report, completed by Humiston&Moore Engineers in January,2014,
reported that"the Clam Pass system seems relatively stable after seven months of post construction
adjustment. The channel entrance is dynamic in nature and seems to shift with the ebb shoal delta in
response to seasonal wave,climate and tidal conditions."
Because the Pass is vulnerable to local weather conditions, it is being monitored very closely. Data for
the 12-month post dredging report is being collected in April, 2014.
Both the three-month and six-month reports are available at PelicanBayServicesDivision.net
March 18,2014 Clam Bay Committee of the Pelican Bay Services Division
Submitted by Tim Hall,Turrell,Hall&Associates,Inc.
) -,,
TURRELL, HALL & ASSOCIATES, INC.
MARINE & ENVIRONMENTAL CONSULTING
3584 Exchange Avenue, Suite B • Naples, Florida 34104-3732 • (239) 643-0166 • Fax (239) 643-6632
MEMORANDUM
TO: PBSD Clam Bay Committee
FROM: Tim Hall
DATE: March 14,2014
RE: Estimated costs for new 10 year permit application and processing
At the request of the Committee, we have put together the following rough estimate of costs associated with our
involvement in the application and processing until issuance of a new 10-year permit for management activities
within the Clam Bay NRPA system. The following proposal anticipates the cost of permitting with the Department
of Environmental Protection Beaches and Coastal Section and the U.S. Army Corps of Engineers. Additional
proposals will be needed form the Engineer and Surveyors for inclusion in the submittal and processing.
1. Prepare and produce environmental documentation required for the application (existing conditions of
system to include seagrass survey,shorebird utilization,biological assessment for Fish and Wildlife Service
and National Marine Fisheries Service) $8,500.00
2. Coordinate and compile application submittal with Engineer and surveyor. $5,000.00
3. Application submittal costs: Application copies (estimated$100.00), FDEP Application Fee(anticipated
$ ) $
4. Processing application through Requests for Additional Information(Assumes no more that 2 requests each
from FDEP and USACE) (Time and materials,not to exceed**) $25,000.00
** If any agency requests additional studies or research, more funds could be required.
5. Miscellaneous reimbursable expenses billed at cost $500.00
Total $39,000.00 plus application cost
October 17,2013 Clam Bay Committee of the Pelican Bay Services Division -
Submitted by Kathy Worley.Conservancy of Southwest Florida
Page 1 of 4
What conditions should trigger a dredging event?
Dredging should occur when it is determined that the hydrologic exchange between the
Gulf of Mexico and the Clam Bay system has been reduced to the point where it has been
determined that the biological integrity of both the Clam Bay estuary and the mangrove
forest are at risk of impairment. Several conditions would have to become evident in
order for a dredging operation to be considered. Further, such conditions would have to
be deemed irreversible by the dynamics of the natural hydrological processes that
influence Clam Pass.The decision of when to dredge is not a straightforward process,but
rather carefully determined by assessing several hydrologic indicators of inlet dynamics
in concert with natural hydrologic forces and biological conditions within the entire
estuary.
Among the many factors that influence inlet dynamics are: inlet current patterns driven
by tides, waves and wind; severe weather; constantly variable inlet hydrodynamics that
are influenced by tidal prism,channel and estuary morphology,slope,elevation,sediment
type(s) and geological features; freshwater inflow; gross geometric variation, flow
velocity; tidal amplitude and phase; shoaling and scouring; and many other factors.
Realistically it is not practical or financially feasible to assess all of these factors. Several
critical factors should be investigated by instituting a monitoring program at locations
throughout the Clam Bay system that have been previously used for this purpose for over
10 years. This will enable comparisons of current and future hydrologic and ecological
indicators to past conditions and provide data for trending analysis overtime. Indicators
including minimum cross-sectional area of the inlet at the "gorge" (the narrowest part of
the inlet); tidal range and high and low tidal phase lag overtime; along with bathyrnetry
and mangrove forest overall vitality should be used to determine whether or not dredging
is necessary.
There are two different circumstances that could necessitate dredging.
1)Clam Pass completely closes due to a storm or natural event or is in eminent danger of
immediate closure following a weather driven event.This situation should be handled as
an emergency in order to prevent impoundment of water within the system.In this case
the inlet should be dredged as soon as possible.
2)The inlet has lost hydraulic efficiency that is not recoverable through natural processes
and the health of the estuary is in jeopardy.This determination is estimated primarily by
comparing current tidal hydraulic monitoring data and analysis,along with historical data
comparisons,current trends,and the present health of the mangrove forest.
Monitoring
The purpose of the monitoring program is to evaluate inlet characteristics on a
comprehensive long-term basis,with less emphasis on day to day,week to week changes,
or even month to month seasonal changes. It is not recommended that evaluations of
hydraulic indicators be based on the usage of short-term datasets as"snapshots"can yield
erroneous conclusions.A protocol of regular monitoring on a long-term basis needs to be
established.This methodology will prevent over-reacting to short term changes that could
revert or adjust themselves back to a state of dynamic equilibrium without resorting to
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October 17,2013 Clam Bay Committee of the Pelican Bay Services Division
Submitted by Kathy Worley,Conservancy of Southwest Florida '
Page 2 of 4
dredging. Many of the hydrologic parameters vary over short-term intervals and thus
long-term monitoring of these indicators is required.
The monitoring program will collect data to determine the minimum inlet cross-sectional
area,high and low tidal phase lag,tidal range and bathymetry.
a) Minimum inlet cross-sectional area: Determined on a yearly basis through
measurements collected at the critical cross-sectional areas previously identified in
Humiston and Moore Hydrologic Reports as Sections A(STA 0+00 to STA 3+00),
B (STA 3+65 to STA 6+10), and C (STA 6+60 to STA 18+00). If the cross-
sectional area is consistently measured at<200ft2 for at least a period of 3-6 months
then this will trigger an evaluation of tidal phase lag and tidal range. The length of
the monitoring period is governed by weather dependent factors specific to the
current conditions(i.e.extreme spring tides,drought,floods,etc.).A cross sectional
area of less than 200ft2 was chosen to indicate that further investigation is
warranted, since it has been determined that this measurement is close to the
equilibrium cross sectional area(particularly at Sections A&B)as these areas tend
to fluctuate around the 200ft2level.
b) Tidal Phase Lag & Tidal Ranges: Once it has been established that the minimum
cross-sectional area is <200 ft2 for a sufficient period of time and is assumed
unlikely to self correct,then the high and Iow tidal phase lag and tidal range will be
investigated. The magnitude of the high and low phase lag is an important indicator
of inlet dynamics. Tidal range can be used as an indicator of whether or not tidal
circulation throughout the system is being effected by inlet shoaling and whether or
not tidal flushing is adequate to prevent impoundment of water particularly in the
upper reaches of the system,which could adversely affect the mangrove forest.Tide
gauges at previously established Iocations (the Gulf of Mexico, registry, south and
north beach boardwalk facilities, and upper Clam Bay) will be maintained to
operate year-round enabling comparison to historical data. Data collected from
gauges will be used to determine high and low tidal phase lag and tidal ranges
within the Clam Bay system.
c) Bathymetry: Once the high and low tidal phase lag have been determined to have
increased and the tidal range has decreased to the extent that tidal flushing is in
jeopardy, and the mangrove system is likely to be adversely affected due to inlet
dynamics,then bathymetry will be performed. As in previous inlet evaluations,the
bathymetric monitoring of the inlet shoals will be evaluated in conjunction with
tidal data and phase lag in determining whether or not another dredging event
should be considered.
Data Assessment
For the purposes of evaluating hydrologic performance all historical data collected
beginning at the 1998 pre-dredge timeframe will be used for comparison to assess current
hydrologic performance. Particular emphasis will be placed on the pre 1998 dredge
conditions in evaluating the current status and trends in tidal range and high and low tidal
phase lag. What is important is whether or not the high and low phase lag and tidal range
data continues to show greater system hydraulic efficiency in comparison to 1998
conditions. If there is a very high probability that the inlet can not self-correct itself and
October 17,2013 Clam Bay Committee of the Pelican Bay Services Division
Submitted by Kathy Worley,Conservancy of Southwest Florida
Page 3 of 4
anthropogenic intervention is absolutely necessary to preserve the viability of the
mangrove system and estuary then dredging will be scheduled.
The attached Flowchart delineates the process that will be used to determine whether or
not a dredging event is necessary.
t ..
0
h
October 17,2013 Clam Bay Committee of the Pelican Bay Services Division
Submitted by Kathy Worley,Conservancy of Southwest Florida °
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Sequence of Events that determine whether or not a dredging event is necessary to
alleviate Environmental Concerns in the Clam Bay NRPA.
`
Monitor Cross-sections,High and Low Tidal Phase Lag,&Tidal Range
A
Is the minimum cross-
sectional area<200 ft2 at NO ,
Segments A,B&C? 1 ► Continue to Monitor
1/4 f
• } YES
NO
r I , NO
Increased Tidal Phase AND Decreased Tidal
Lag?2 4 ■ Range?2
►
L J
1YES
NO Is Dredging Necessary to Prevent Ecological Damage to the Mangrove System?
Does recent Bathymetric Surveys Indicate Significant Shoaling?
Is there a High Probability that the situation can not naturally rectify itself?
1
YES
v.
t
Dredge Template
I. Design Phase
t
YES
. ,
Authorization by
Agencies to Proceed
YES l YES
r
Seagrass Survey
Seagrass located within Dredging Template?
,
Jr NO
,
Begin Dredging
'In the event that the Pass completely closes due to a storm or other natural event and is in eminent
danger of immediate closure this should be treated as an Emergency-proceed directly to Dredge
Template Design Phase to expedite the process.
2 The length of the monitoring period is intuitively governed by weather dependent factors specific to
the current conditions(i.e.extreme spring tides,draught,floods,etc.).Conclusions are derived in the
context of overall long-term trends.