Agenda 06/30/2016PELICAN BAY SERVICES DIVISION
Municipal Service Taxing and Benefit Unit
NOTICE OF PUBLIC MEETING
JUNE 30, 2016
THE CLAM BAY COMMITTEE OF THE PELICAN BAY SERVICES
DIVISION WILL MEET AT 1:00 PM ON THURSDAY, JUNE 30 AT THE
PELICAN BAY SERVICES DIVISION, 3RD FLOOR OF THE SUNTRUST
BUILDING, SUITE 302, LOCATED AT 801 LAUREL OAK DRIVE,
NAPLES, FLORIDA 34108.
AGENDA
1. Roll call
2. Agenda approval
3. Approval of 04/26/16 meeting minutes
4. Audience comments
5. Mangrove die -off report and photos
6. Tidal gauge data
a. June 1-27 tidal gauge data
b. Historical tidal gauge data
7. Hand -dug channels in Upper Clam Bay
a. Missing channels
b. Additional work or channels needed
c. Permit that may be needed
8. Shoal and meandering channels impacting tidal flow
a. Location
b. Previous work and bathymetric surveys done in this area
9. Monitoring and restoration of mangrove die -off
10. Extension of FDEP dredging permit
11. Timeline for osprey nesting platform near Marker 36
12. Performance to date of tidal gauges
13. Copper results
14. Total nitrogen and total phosphorus results
15. Next meeting: August 31, September 1 or 2
16. Other
17. Adjournment
ANY PERSON WISHING TO SPEAK ON AN AGENDA ITEM WILL RECEIVE UP TO THREE (3) MINUTES 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:HPELICAN BAYSERVICESDIVISION.NET.
06/24/2016 9:43 AM
PELICAN BAY SERVICES DIVISION
CLAM BAY COMMITTEE MEETING
APRIL 26, 2016
The Clam Bay Committee of the Pelican Bay Services Division met on Tuesday, April 26 at 9:00
a.m. at the SunTrust Bank Building, 801 Laurel Oak Drive, Suite 302, Naples, Florida 34108. In
attendance were:
Clam Bay Committee
Susan O'Brien, Chairman
Pelican Bay Services Division Staff
Neil Dorrill, Administrator (absent)
Marion Bolick, Operations Manager
Also Present
Mohamed Dabees, Humiston & Moore
Jacob Damouni, PBSD Board
Robert Naegele, PBPOA
Jeremy Sterk, Earth Tech
Bohdan Hirniak (absent)
Gary Ventress
Mary McCaughtry, Operations Analyst
Lisa Jacob, Associate Project Manager
Barbara Shea, Recording Secretary
APPROVED AGENDA (AS AMENDED)
1. Roll call
2. Agenda approval
3. Approval of 02/24/16 meeting minutes
4. Audience comments
5. Hand -dug channel work
6. Osprey nesting platform near marker 36
7. Status of dredging project
8. Mangrove die -off monitoring
9. Data for January, February, March, and April from tidal gauges
10. Quarterly water quality reports (Turrell, Hall quote)
11. Monthly water quality results
a. Dune swale work — Basin 6 (add-on)
12. Other
13. Adjournment
ROLL CALL
Mr. Hirniak was absent and a quorum was established
Pelican Bay Services Division Clam Bay Committee Meeting
April 26, 2016
ENDA APPROVAL
Mr. Ventress motioned, Ms. O'Brien seconded to approve the agenda as amended
with the addition of Item #11a, The motion carried unanimously.
AL OF 02/24/16 MEETING
Ms. O'Brien motioned, Mr. Ventress seconded to approve the 02/24/16 meeting
minutes as amended. The motion carried unanimously.
AUDIENCE COMMENTS
None
HAND -DUG CHANNEL WORK
Mr. Jeremy Sterk, of Earth Tech, provided a map of Basin 6 which showed the locations
and depths of those hand -dug channels for which his teams have completed examinations. They
are in the process of mapping locations and depths of all of the hand -dug channels, and
simultaneously recording the conditions of those channels as well as the locations of any exotics.
Mr. Sterk requested that staff provide him a copy of the infrared photo which identifies
those areas of significant mangrove die -off in Upper Clam Bay to determine if a correlation
exists with those areas of clogged or non-existent hand -dug channels. He reported that a
significant area in the northern section of Basin 6 has no hand -dug channels, despite existing
maps showing their existence.
Staff reported that a work order has been issued for maintenance work of the hand -dug
channels for a total of 27 days of work.
UPDATE ON ERECTING AN OSPREY NESTING PLATFORM NEAR MARKER 36
Ms. Jacob reported that Mr. Dorrill contacted Mr. Hoppensteadt, President of the Pelican
Bay Foundation, to discuss the possibility of an osprey nesting platform on PBF North Beach
Facility/Marker 36 property. Mr. Hoppensteadt is open to the idea. Additional discussion is
required to identify the source of funding for this project.
STATUS OF DREDGING PROJECT
Dr. Dabees reported on the progress of the Clam Pass dredging project and estimated
completion by May 5. Mr. Damouni commended Ms. Jacob for her dedication to the oversight
of this project.
MANGROVE DIE -OFF MONITORING
Ms. Jacob reported that staff is in the process of obtaining a new proposal from Turrell,
Hall for mangrove die -off monitoring, commencing in May 2016.
DATA FOR FEBRUARY AND MARCH FROM TIDAL GAUGES
Dr. Dabees reported that the new tidal gauges were not fully functional in January, and
therefore, no report for January will be available. He reviewed the February and March tidal
gauge data with the committee. Dr. Dabees expects to see some improvement in future monthly
reports as a result of the dredging event. He reported that one gauge is "off-line" and that Mr.
Sterk will troubleshoot this issue.
2
Pelican Bay Services Division Clam Bay Committee Meeting
April 26, 2016
QUARTERLY WATER QUALITY REPORTS
Ms. Jacob reported that the first quarterly water quality report, to be completed by
Turrell, Hall, will cover November, December and January. Ms O'Brien requested staff to
establish due dates for subsequent quarterly reports.
MONTHLY WATER QUALITY RESULTS
Ms. Jacob reported that the County Lab's turnaround time for reports on water samples to
be 6-9 weeks.
DUNE SWALE WORK — BASIN 6
Ms. Jacob reported that our engineering firm, Agnoli, Barber & Brundage, has not
completed the interpretation of the topographic survey of the dune Swale along the Bay Colony
beach. Mr. Sterk reported that there are no hand -dug channels in this area as previously thought.
Mr. Bolick reported that the swale is clogged and requires maintenance work.
ADJOURNMENT
The meetiniz was adiourned at 9:48 a.m.
Susan O'Brien, Chairman
Minutes approved [ ] as presented OR [ ] as amended ON [ ] date
TO:
Agenda Item #5 and #7
Page 1 of 10
TURRELL, HALL & ASSOCIATES, INC.
MARINE & ENVIRONMENTAL CONSULTING
3584 Exchange Avenue, Suite B • Naples, Florida 34104-3732 • (239) 643-0166 a Fax (239) 643-6632
MEMORANDUM
PBSD Clam Bay Committee c/o Neil Dorrill
FROM: Tim Hall
DATE: June 24, 2016
RE: Die -off status, hand -dug channels, and future permitting
Neil,
Since I will be out of town during the upcoming Committee and Board meetings I have provided a written summary
in response to a few questions that have been asked.
DIE -OFF STATUS
At the request of the Board we have been keeping an eye on the status and extent of the new die -off area up near the
Strand. I had estimated about 7.76 acres of dead areas back in January 2016. Based on the most recent aerials
flown this month and some ground truthing, the area dying back has doubled in size since January. The area where
vegetation was largely dead now totals approximately 15.04 acres, with other nearby areas showing signs of stress
as well. There were small seedlings present in the northern die -off area and some signs of leave growth on a few of
the larger trees which did not die completely, but the area behind the strand was mostly dead white mangroves.
I still believe that the die -off was mainly the result of lower exchange through the Pass and the inability of water to
get out of the north end of the system, not a result of any blocked hand -dug channels. The heavy rains in January
and February simply overwhelmed the capacity of the Pass at that time and so water stacked up in the mangroves
similar to what happened in 1995.
We have included some photographs from the site visit, a map of the January die -off limits and a map of the June
die -off limits for your use.
HAND -DUG CHANNELS
The simple explanation for the three "missing" channels is that we messed up with the exhibit. Back in 2004/05
when we originally laid out the remaining channels we had shown three channels at the very north end of the
system. However, further investigation when the channels were being dug in 2006 indicated that that area was in
very good shape and the channels were not needed so they were never installed. Those three channels were not
shown on any annual report exhibits prior to 2013 or on the FDEP maintenance permit. Jump forward to 2013 when
we were updating exhibits for the management plan, somehow we used the GPS points for the 2004/05 proposed
channels instead of the installed channels and I did not catch the error. I don't use that exhibit when checking the
channels and just didn't realize that those three had been added back on. We have corrected that and sent the right
layout to Lisa.
Agenda Item #5 and #7
Page 2 of 10
PERMITTING
I am still not convinced that any new channels are needed through the mangroves though we are looking at one
channel that would run parallel to the strand wall from north to south and help move water that does look to be stuck
in places along the wall. It is immediately next to the wall where some of the new die -off seems to be concentrated
as well. Permitting would involve a new permit application to FDEP to add the new channel into our existing
network. The construction portion of the FDEP permit expired in 2015 but the operation portion of it allows us to
keep maintaining the existing channels. We would also have to modify the USACE permit to add any new channel.
The USACE permit is good until 2021 so a simple modification is all that would be needed. The USACE is still
backed up a bit so I would expect to spend 9 to 12 months with them to get the modification. FDEP should take 6 to
9 months for the new permit.
If you have any further questions while I am away please contact Arielle, Jeff or Marielle. Arielle will be attending
the meeting in my stead on the 6th
Sincerely,
Tim Hall
Senior Ecologist
Page 6 of 10
PHOTOGRAPHIC DOCUMENTATION
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Agenda Item #6a
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Mean Low Tide Lag: time difference between low tide in the Gulf of Mexico and at the gage's locations, averaged over a month in
minutes. The time lag is also represenattive of the pass's effectiveness in flushing water from the bay. The higher the lag the less
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Agenda Item #9
Page 1 of 1
>"4 TURRELL, HALL & ASSOCIATES, INC.
MARINE & ENVIRONMENTAL CONSULTING
3584 Exchange Avenue • Naples, Florida 34104-3732 • 239-643-0166 • Fax (239) 634-6632 • thall@turrell-associates.com
May 3, 2016
Pelican Bay Services Division
801 Laurel Oak Drive, Suite 605
Naples, FL 34108
Re: Proposal for Environmental Services- Contract 15-6397
Monitoring of Mangrove Die -Off Area
Turrell, Hall & Associates is pleased to provide you with this proposal for environmental
management services to inspect the new die -off area at the north end of Clam Bay on a monthly
basis and report to the various Boards as requested. Our scope of services on a per month basis
is as follows:
1. Fly monthly aerials of die -off area for comparison and presentation to the
Board/Committee.............................................................$250.00 Lump Sum
2. Groundtruth the die -off area each month to document the changes in vegetation cover and
species........................................................................$1,050.0 Lump S
0 Lu um
3. Provide Pelican Bay Services Division with a monthly summary memo of
findings..........................................................................$175.00 Lump Sum
4. Attend Monthly Board Meeting (and Committee Meetings if requested) to present
findings ........................$350.00 Board ($350.00 Committee if requested) Lump Sum
5. Miscellaneous Additional Services Requested by Pelican Bay Services
Division................................................................................$700.0
0 T&M
Total Cost Monthly Cost......... LS $1,825.00 ($2,175- if extra meeting requested) + T&M $700.00
Total 12 Month Cost..................................................................Not to Exceed $34,500.00
Please feel free to call me with any questions.
Sincerely,
Tim Hall
Vice President
4350 West Cypress Street
Suite 950
Tampa, FL 33607
813.207.7200 phone
813.207.7201 fax
memorandum
date May 2, 2016
to Tim Hall, Turrell, Hall and Associates, Inc.
from David Tomasko, Ph.D.
Emily Keenan, M.S.
subject Quarter 1: Clam Bay NNC SSAC evaluation
Background
Agenda Item #14
Page Vvofkesassoc.com
The United States Environmental Protection Agency (EPA) and Florida Department of
Environmental Protection Agency (FDEP) adopted site specific alternative nutrient criteria
(SSAC) for Clam Bay, as listed in Florida Administrative Code (FAC) 62-302.531. The SSAC
were derived based upon a nutrient: salinity relationship from the Estero Bay Wetlands, a
reference waterbody for water quality, as established by FDEP in prior TMDI_s. The SSAC for
Clam Bay is considered in the context of salinity due to the variability in nutrient concentrations
found within a given salinity range. Therefore, the appropriate management response
associated with any impairment determination is based upon the magnitude and duration of
any exceedances.
Based on prior work that showed that phytoplankton growth in Clam Bay was likely stimulated
by both Total Nitrogen (TN) and Total Phosphorous (TP) both TN and TP are used to
determine eutrophication status. As outlined in FAC 62-302.531, water quality status is
determined on an annual basis, preferably within a calendar year. Within a calendar year,
each individual TN and TP value collected within the waterbody is compared to the nutrient:
conductivity 90th percent prediction limit (Figure 1). An annual percent exceedance is
calculated to determine the magnitude of exceedance. To be consistent with the method
currently implemented by FDEP to identify impaired water bodies, if 13 percent or more of the
TN or TP values in a calendar year exceed the 90th percent prediction limit (after being
normalized for conductivity) the duration of exceedance would then be determined. Based on
the duration of exceedance (one year or greater than one year), the outcome designation is
assigned. If fewer than 13 percent of the values exceed the 90th percent prediction limit, then
the outcome is "0". If the magnitude (i.e., 13 percent) and duration (i.e., less than 1 year) of the
exceedances are deemed small, the outcome is "1 ". If the magnitude or duration of the
exceedances is large, then the outcome is "2". If both the magnitude and duration of the
exceedances are large, then the outcome is "3". The management response for Clam Bay
Agenda Item #14
Page 2 of 5
would be determined based on the outcomes assigned to both the TN and TP evaluations for
the magnitude and duration of exceedance (Figure 2).
The water quality status of Clam Bay would be assigned a green, yellow, or red designation
annually based on the magnitude and duration of exceedances of the 90th percent prediction
limit. The color designation is then used to determine what level(s) of management actions are
appropriate.
Annual management response actions are based on the response to nutrient concentrations of
phytoplankton and dissolved oxygen (DO) as well as impacts on water clarity (Figure 3). If the
outcome of the TN and TP evaluation is green, then no management actions are required.
However, if the outcomes are yellow or red then further evaluation of the effect of elevated
nutrient concentrations on both phytoplankton biomass and DO concentrations need to be
reviewed. If there is no relationship between nutrients and chlorophyll -a or DO, then no
management actions are required. If there is a signification relationship, then the impact of
chlorophyll -a on the water clarity
(Secchi disk depth) would be evaluated. If there is no relationship between chlorophyll -a and
water clarity, then no management actions are required. If there is a significant relationship
between chlorophyll -a concentrations and water clarity, an outcome designation of "yellow"
(indicative of small magnitude or duration of exceedances) identifies that management actions
should be taken to identify the potential causes and responses for the elevated nutrient levels.
It the outcome designation is "red" (indicative of a large magnitude or duration of
exceedances), management actions should be taken to implement recommended response
tactics to reduce nutrient concentrations. The "health" of Clam Bay is to be assessed annually
in this manner.
Figure 1. Clam Bay water quality flow chart.
Agenda Item #14
Page 3 of 5
Figure 2. Management response matrix using outcomes from both TN and TP
evaluation.
Figure 3. Management response actions in response to various outcomes.
dl difference or
rt duration
entify potential
Cd Uses and
responses
Total Phosphorus
Total Nitrogen
Outcome U
Outcome 1
Outcome 2
Outcome 3
Outcome U
Outcome 1
Outcome 2
Outcome 3
Figure 3. Management response actions in response to various outcomes.
dl difference or
rt duration
entify potential
Cd Uses and
responses
Agenda Item #14
Page 4 of 5
Data Analysis
The analysis conducted below was used to assess the water quality status of Clam Bay from
November 2015 to January 2016. Since the SSAC developed for Clam Bay is to be evaluated
on an annual time step, this analysis provides insight into current water quality conditions
within the Bay, but it does not substitute for the more comprehensive annual assessment
required. Clam Bay surface water quality data were provided by Turrell, Hall and Associates,
Inc. for comparison with the FDEP adopted SSAC established for Clam Bay and found within
FAC. 62-302-532 -1-j. The NNC SSAC states the following;
"No more than 10 percent of the individual Total Phosphorus
(TP) or Total Nitrogen (TN) measurements shall exceed the
respective TP Upper Limit or TN Upper Limit. "
The TP and TN upper limits are calculated using equations 1 and 2:
Equation 1: TP Upper Limit (mg/L)= e(-1.06256-0.000032s465`conductivity(us))
Equation 2: TN Upper Limit (mg/L)= 2.3601 — 0.0000268325*Conductivity(pS)
The dataset was supplemented with in situ water quality data (e.g., temperature, dissolved
oxygen, pH, conductivity, and salinity) retrieved from the chain of custody forms for each
sampling event. The corresponding TN or TP Upper Limit was calculated for each Clam Bay
estuarine water quality station and sampling date in which conductivity was available using
Equations 1 and 2. TN and TP concentrations were compared to the derived upper limit
thresholds to ascertain if elevated concentrations were identified (Appendix A).
Over the period analyzed (November 2015 to January 2016) a single ambient water quality TN
measurements exceeded the respective TN Upper Limit. In comparison, 2 of the 27 (7
percent) TP measurements exceeded the respective TP Upper Limit. Based on this time
period, the frequency of exceedance, if maintained over the course of a calendar year, would
not be determined to be impaired, and the likely outcome would be a value of "0".
The TN exceedance occurred at Clam Bay 9 on November 17, 2015. Similar to the previous
review (Technical Memo dated January 15, 2016), the TP exceedances occurred at Clam Bay
2 on November 17, 2015 and Clam Bay 1 on January 13, 2016; both stations are located in
Upper Clam Bay.
In addition, the Clam Bay Outfall monitoring station results were compared to the proposed
downstream protective values (DPV) for Clam Bay which are based upon "pristine" conditions
of Estero Bay (PBS&J 2011). Outfall TN and TP concentrations were compared to the median
and 90th percentile DPV values to determine if elevated concentrations were identified
(Appendix B).
The median and 90th percentile DPVs for TN are 1.31 and 1.8 mg/L, respectively. The median
and 901h percentile DPVs for TP are 0.1 and .25 mg/L, respectively. For TN, 47 and 32 percent
of the values exceeded the median and 90th percentile DPV values, respectively (Table 1). For
4
Agenda Item #14
Page 5 of 5
TP, 68 and 11 percent of the reported values exceeded the median and 90th percentile DPV
values, respectively (Table 1).
Table 1. Percentage of TN or TP concentrations from outfall stations which exceeded
the median or 90th percentile DPV values.
DPV I Total Nitrogen Total Phosphorus
Median 90th Percentile Median 90th Percentile
BelowI 53% 68% 32% 89%
Exceed 47% 32% 68% 11%
Findings
It should be noted that this data analysis is not conducted based on a full year of water quality
data, and thus is indicative of potential findings for a calendar year, but is not necessarily
predictive of what would be found with a calendar years' worth of data. The FDEP-adopted
SSAC for Clam Bay requires data analysis on a calendar year basis (FAC 62-302.531).
However, quarterly status reports can be useful as an early warning system if water quality
appears to be significantly different from expected ranges. Also, this effort required
conductivity data to be derived based on salinity for some of the months examined. This issue,
while not major, suggests a change in the data recording effort for field monitors (since both
parameters are displayed on most water quality meters) is warranted.
Preliminary evidence (see above) suggests that nutrient concentrations in Clam Bay are not
currently problematic, but that nutrient concentrations in stormwater runoff could be
problematic in the future.
Elevated nutrient concentrations in some of the outfall sampling locations suggests that some
of the TP concentrations in Upper Clam Bay could be due to activities occurring on the
watershed, and outfall sampling should continue.
Additionally, the finding that nutrient concentrations in runoff are elevated compared to
protective criteria, while the open waters of the bay itself appear to be unimpaired suggests
that the maintenance of the flushing influence of Clam Pass is important to the water quality of
Clam Bay. If Clam Pass was to close for some reason, the elevated nutrient concentrations
from watershed runoff (compared to undeveloped watersheds) would likely result not only in
the expression of eutrophication through mechanisms such as phytoplankton and/or
macroalgae blooms, but stagnant water conditions would likely result in Clam Bay exceeding
its FDEP-adopted water quality standards.
Rainfall in inches at Naples Airport
n.b. Bay Colony residents began reporting signs of mangrove die -off in the fall of 2015.
1 Through June 26, 2016
2014
2015
2016
January
2.39
.10
8.30
February
.77
1.33
1.11
March
1.53
1.45
.45
April
1.80
1.75
.47
May
1.97
3.18
2.48
June
8.18
5.82
4.081
July
6.95
9.91
August
13.89
2.78
September
10.08
6.46
October
1.43
1.20
November
1.05
2.62
December
.25
1.64
Total
50.29
38.24
n.b. Bay Colony residents began reporting signs of mangrove die -off in the fall of 2015.
1 Through June 26, 2016
wManassm
EXCEEDED STATE STANDARD DE r. 3.7 ug/L
❑1 N 'll t:3' +'� i15
co 'w, C7 W M ® ®'HCl
z�
-•IDp Co •tr.�i'"M Vl. a. wf
00 040 �03 00 17
County Lab
Benchmark
Clare
Bay 1
Clam
Bay 2
Clare
Bay 3
Clam
Bay 4
Clare
Bay 5
Clam
Bay 6
Clam
Bay 7
Clam
Bay 8
Clam
Bay 9
3/2/15
3/26/15
1.54
4.97
20.10
3.93
1.12
4.68
0.50
3.50
0.35
3.00
0.35
3.58
0.35
3.00
0.35
3.00
0.35
3.00
4/29/15
5/26/i5
4.70
4.49
4.49
2.66
3.39
1,24
0.65
1.37
4.73
0.27
1.71
0.27
0.94
0.35
1.69
0.36
1.51
1.91
6/30115
3.04
2.16
0.47
3.08
0.27
0.27
2.04
0.27
0.27
7/16/15
4.91
11.20
4.15
2.66
1.58
4.14
7.12
3.28
1.53
8/26/15
9/16/15
0.88
2.77
1.46
11.60
1.89
3.10
1.43
2.19
2.10
0.54
1.05
0.50
4.36
0.90
3.68
0.27
3.61
0.39
10/21/15
1.85
1.30
0.835
1.76
0.272
1.20
3.36
0.551
0.547
11/17/15
12/09/15
2.39
2.037
2.21
4.306
2.16
2.631
1.75
0.272
1.09
0.272
0.864
0.538
1.37
0.901
0.910
1.415
0.684
0.272
1/13/16
3.89
8.91
4.29
2.15
1.44
1.17
0.854
0.558
0.510
2/25/16
3.46
9.48
1.70
2.14
0.272
0.272
0.411
0.278
0.272
3/23/16
1.88
2.08
0.679
0.500
0.500
0.500
0.500
0.500
0.500
3/23/16
0.272
1 1.05
10.272
0.272
0.272
0.272
0.272
0.272
0.272
4/27/16
0.270
1 0.270
0.270
0.270
0.270
0.270
0.270
0.270
0.270
EXCEEDED STATE STANDARD DE r. 3.7 ug/L
❑1 N 'll t:3' +'� i15
co 'w, C7 W M ® ®'HCl
z�
-•IDp Co •tr.�i'"M Vl. a. wf
00 040 �03 00 17
County Lab
Benchmark
HUMISTON
& MOORE
ENGINEERS
COASTAL
ENGINEERING DESIGN
AND PERMITTING
June 30, 2016
Pelican Bay Services Division
c/o Mr. Neil Dorrill, Administrator
801 Laurel Oak Drive, Suite 302
Naples, FL 34108
Re: Clam Pass — Upper Channel Reconnaissance Survey
H&M File No. 23065
5679 STRAND COURT
NAPLES, FLORIDA 34110
FAX:239 594 2025
PHONE: 239 594 2021
Please find enclosed the results of the recent reconnaissance survey completed in the primary upper
clam bay channels. Specifically, the major connecting channels were surveyed from the Pelican Bay
South Boardwalk to Upper Clam Bay. The survey was completed March 10, 2016 by ABB. The 2016
survey consisted of spot elevations at approximately mid -channel at regular intervals to investigate if
the channel had shoaled. This provides a record of current channel depths. Survey data from 2008
are also provided for reference.
The scope of the survey is illustrated in the attached figures, along with the data point locations from
2016 and 2008. For ease of presentation, the channels are divided into three reaches, roughly
corresponding with the three areas that were previously dredged, known as Cut 1, Cut 2 and Cut 3.
Cut 1 is located in the channel from Inner Clam Bay to Upper Clam Bay. Cuts 2 and 3 are located in
the channel from the Pelican Bay South Bridge to Inner Clam Bay.
The preliminary assessment indicates that depths have not changed substantially throughout these
connecting channels. Nearly all spot elevations indicate elevations below reasonable thresholds for
each channel.
When averages are taken of the elevations recorded in the previous cut areas, the values are as
follows:
Average Elevations (Feet NAVD)
Cut 1 Cut 2 Cut 3
2008 -4.7 -4.7 -5.1
2016 -4.7 -4.4 -4.9
At this time we do not believe that the data indicate a need for further bathymetric assessment of this
area. If in the future new information suggests constriction in these channels, a much more intensive
survey effort will be required. If there are any questions or concerns please contact me.
Sincerely yours,
HUMISTON & MOORE ENGINEERS
Mohamed A. Dabees, P.E.
Clam Bay 2016 Reconnaissance Survey
Connecting Channels Between Bays
'�.
Cut 1- Inner Clam Bay to Upper Clam Bay
o �ry0 P'i1 pati y�° bP e 1°1� 1°�h 1ti1�1�.��A 1y� '0,
0 Ma
-2
i
a
Z
4 +- _-.._.._.._....
s
0
South
Cut 1 Area
. 2008
® 2016
North
■ 2008 ■ 2016 Recommended Elevation below -2' NAVD
Distance South to North (Feet)
A 2008
® 2016
Cut 2 Area
0
Cut 2 - Inlet to Inner Clam Bay - North
v�1 �y0 byA ,'`~� ^�a `bey °jb.Y O� �b9 goy^p 3.y0 b,�y p�h 'titi y10 6,yy ��b ^�ti 1
�3 X01 0� yQti
1 1 ti, 141101 11 1 .ti,, .t,. �, •y, n�� •y. -y �j. �, I 4 li l 1• 1• -y n�� �• n�, n�• p• b• b b• b• p. b. b.
South 92008 M2016 Recommended Elevation below -T NAVD North
-10
Distance South to North (Feet)
_2
0
a
z
w -4
e
0
Cut 3 - Inlet to Inner Clam Bay - South
btip
0 Opo
+01110 b1 �ti dy1 ti• mph �y,� ��O X16 PtiM ay0 �ry,� hy0 y�3 Oti5 6�6 ppA stip �p3 ��p �,y1, �y1 ��A pp
tip
O 'ti ti h 6 1 'b of ti, ti• ti• '�,• ti, y, y, �., .y, .y, .y, �., ti., '�, ti ti '� '�, '�• ti ti ti ti
-10
2008
2016
Cut 3 Area
Distance South to North (Feet)