PBSD MSTBU Clam Bay Committee Agenda 07/11/2019 PELICAN BAY SERVICES DIVISION
Municipal Service Taxing and Benefit Unit
NOTICE OF PUBLIC MEETING JULY 11, 2019
THE CLAM BAY COMMITTEE OF THE PELICAN BAY SERVICES DIVISION WILL
MEET AT 1:30 PM ON THURSDAY, JULY 11 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 05/09/19 meeting minutes
4. Audience comments
5. Clam Bay
a. Hand-dug channel maintenance
b. Canoe trail markers 10 and 12
c. Scaevola treatment
d. Canoe Trail guide
e. Pelican Bay Post articles
6. Clam Pass
a. June tidal ratio report
b. June aerial photos
c. Bathymetric survey results
d. Data on Clam Pass dredging
7. Water Quality
a. First quarter report
b. Copper results
c. Impact of pond contamination on Clam Bay
8. Next meeting: September 10 or 12, 2019
9. 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.
07/05/2019 10:26 AM
PELICAN BAY SERVICES DIVISION
CLAM BAY COMMITTEE MEETING
MAY 9,2019
The Clam Bay Committee of the Pelican Bay Services Division met on Thursday, May 9 at 1:30
p.m. at the SunTrust Bank Building, 801 Laurel Oak Drive, Suite 302,Naples, Florida 34108. In
attendance were:
Clam Bay Committee Denise McLaughlin
Susan O'Brien, Chairman Rick Swider (absent)
Pelican Bay Services Division Staff Mary McCaughtry, Ops. Analyst (absent)
Neil Dorrill, Administrator Barbara Shea, Recording Secretary
Lisa Jacob, Interim Operations Manager
Also Present Jeremy Sterk, Earth Tech
Mohamed Dabees, Humiston& Moore Scott Streckenbein, PBSD Board
APPROVED AGENDA (AS AMENDED)
1. Roll call
2. Agenda approval
3. Approval of 03/07/19 meeting minutes
4. Audience comments
5. Clam Bay
a. March mangrove monitoring
b. Canoe trail markers 10 and 12
c. Hand-dug channel maintenance
d. Scaevola treatment
e. Submittal of articles to the PB Post (add-on)
6. Clam Pass
a. April tidal ratio report
b. April aerial photos
c. Bathymetric survey
d. Cost information for dredging Clam Pass
e. Data on Clam Pass dredging
7. Water Quality
a. Next quarterly report
b. Copper results
c. Update on WIN
d. Impact of pond contamination on Clam Bay
8. Next meeting: July 9 or 11, 2019
9. Adjournment
1
Pelican Bay Services Division Clam Bay Committee Meeting
May 9,2019
ROLL CALL
Mr. Swider was absent and a quorum was established
AGENDA APPROVAL
Ms. O'Brien motioned, Ms. McLaughlin seconded to approve the agenda as
amended with the addition of item #5e. The motion carried unanimously.
APPROVAL OF 03/07/19 MEETING MINUTES
Ms.O'Brien motioned,Ms.McLaughlin seconded to approve the 03/07/19 meeting
minutes as amended. The motion carried unanimously.
MS. O'BRIEN WELCOMED OUR NEW COMMITTEE MEMBER MS. DENISE
MCLAUGHLIN
AUDIENCE COMMENTS
Mr. Peter Duggan requested information on the trimming of mangroves about ten yards
from the beach in Clam Pass Park, about two years ago. Mr. Dorrill responded that this area is
outside our jurisdiction and suggested Mr. Duggan call Mr. Barry Williams, Director of County
Parks& Rec.
CLAM BAY
MARCH MANGROVE MONITORING
Mr. Jeremy Sterk, Environmental Consultant with Earth Tech, provided a table of the
March mangrove monitoring plots. He noted that the health scores in the TH-5 area have slightly
declined. All other monitored areas are stable or improving. He reported that Earth Tech has
continued mapping additional hand-dug channels. This summer's hand-dug channel maintenance
will be concentrated in the TH-5 area. He will provide a plan for this year's channel maintenance
to Ms. Jacob so that the project can be bid out as soon as possible.
CANOE TRAIL MARKERS 10 AND 12
Mr. Sterk reported on a recent conversation with Mr. Chris D'Arco, Sr. Field Inspector of
the Collier County Coastal Zone Management, who suggested that the County may be able to re-
install canoe trail markers 10 and 12 in July or August. Ms. Jacob commented that a permit
modification would be required to change the location of any of these canoe trail markers. Mr.
Dorrill commented that he would follow up on the re-installation of these two markers with Mr.
Gary McAlpin, Manager of Collier County Coastal Zone Management.
• Ms. O'Brien commented that the PBF has never received the new updated version of the
Clam Bay canoe trail brochure. Ms.Jacob commented that when the process of updating the canoe
trail brochure began, we agreed to pay Earth Tech for working on the update, and Mr.
Hoppensteadt agreed that the PBF would pay for printing. Mr. Dorrill will follow up on this issue
with Mr. Hoppensteadt, and a new canoe trail brochure will be available to residents as soon as
possible.
HAND-DUG CHANNEL MAINTENANCE
2
Pelican Bay Services Division Clam Bay Committee Meeting
May 9, 2019
Mr. Sterk commented that he estimates this year's hand-dug channel maintenance to be
approximately $30-35,000.
SCAEVOLA TREATMENT
Mr. Sterk provided an exhibit(included in the agenda packet) showing scaevola areas that
are visible using aerial interpretation. He suggested that the next step would be to "ground truth"
this documentation. He recommended focusing on areas with a tortoise population, as scaevola
typically crowds out native vegetation. Mr. Sterk suggested that if we could piggyback with the
County on a similar scaevola removal project, we could lower our overall cost.
SUBMITTAL OF ARTICLES TO THE PB POST
Ms. McLaughlin commented that a lot of information covered in this meeting would be of
interest to our residents. She volunteered to draft a few educational articles for the PB Post for
review by our board members.
CLAM PASS
APRIL TIDAL RATIO REPORT
Ms. O'Brien reported that the April tidal ratios look good.
APRIL AERIAL PHOTOS
The committee reviewed April Clam Pass aerial photos. Dr. Dabees provided a brief
overview of the inlet features and fundamentals of the Clam Pass system. Mr. Dorrill commented
that monthly aerial photos include not only shots of Clam Pass, but also shots of those mangrove
areas which have been historically stressed and those adversely affected by Hurricane Irma. Mr.
Sterk noted that we are seeing mangrove regrowth in most of the stressed mangrove areas.
The committee agreed that we should continue to include the ten monthly photos of Clam
Pass in the PBSD Board Regular Session agenda packet.
BATHYMETRIC SURVEY
Dr. Dabees reported that the Clam Pass bathymetric survey work has been completed, and
that the data should be provided to him next week.
COST INFORMATION FOR DREDGING CLAM PASS
Mr. Dorrill clarified that Mr. Swider had requested information (in Feb./Mar 2019) on
payments to our consultants for Clam Bay (not Clam Pass dredging) as backup information for
discussion by the Budget Committee on the possible budgeting of a new in-house environmental
specialist.
DATA ON CLAM PASS DREDGING
Dr. Dabees commented that we are on schedule to discuss our historical data on Clam Pass
dredging at our July committee meeting. This data will ultimately be provided to the County
Manager's Office to address their concerns.
WATER QUALITY
NEXT QUARTERLY REPORT
3
Pelican Bay Services Division Clam Bay Committee Meeting
May 9, 2019
Ms. O'Brien commented that we are waiting on the January water quality data from the
County Lab. The first quarter water quality report cannot be completed until this data is received.
COPPER RESULTS
Ms. O'Brien commented that during the first four months of this year, we only had one
instance in our nine Clam Bay sampling sites where copper exceeded an acceptable level.
UPDATE ON WIN
Ms. O'Brien commented that information on WIN (Watershed Information Network) was
provided in the agenda packet. She noted that the County Lab is entering data from 2017 to the
present into WIN.
IMPACT OF POND CONTAMINATION ON CLAM BAY
Ms. O'Brien commented on possible impact of pond contamination on Clam Bay from the
Easter Sunday sewer pipe break. She commented that the last County water quality testing report,
dated April 26, showed two test sites (including the St. Maarten/St. Thomas pond) that were still
out of compliance. Ms. Jacob commented that she will follow up on this issue with the County
Pollution Control Division on May 10.
NEXT MEETING:
By consensus,the committee agreed that the next meeting of the committee would be held
on July 11, 2019 at 1:30 p.m.
ADJOURNMENT
The meeting was adjourned at 2:58 p.m.
Susan O'Brien, Chairman
Minutes approved 1 1 as presented OR 1 1 as amended ON I ] date
4
humistonandmoore I ClamPass-TIDE Agenda item#6a
Page 1 of 1
CLam Pass Tide Monitoring- Click here for Maintenance Dredging Project details
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Agenda item#6c
Page 1 of 1
CLAM PASS MAINTENANCE DREDGING-COLLIER COUNTY
May 2018,November 2018,May 2019
2018-05-10 2018-11-06 2019-05-02
Measured Measured Measured
Volumetric Total Volumetric Total Volumetric Total
Effective Rate Volume Rate Volume Rate Volume
Easting Northing Azimuth Distance (CY/FT) (CY) (CY/FT) (CY) (CY/FT) (CY)
-4+00 387,464.97 686,291.39 180 100.0
o -3+00 387,564.96 686,292.28 180 100.0
N -2+00 387,664.95 686,293.18 180 100.0 3.6 363.0 2.4 238.9
-1+00 387,764.95 686,294.08 180 150.0 5.8 874.4 3.7 557.0
0+00 387,864.94 686,294.98 180 125 0.0 0.0 7.5 94.2 7.1 178.3
0+25 387,889.94 686,295.20 180 25.0 8.6 213.8
0+50 387,914.94 686,295.42 180 25.0 0.0 0.0 9.9 247.8 6.7 336.9
0+75 387,939.94 686,295.65 180 25.0 11.7 292.7
1+00 387,964.94 686,295.87 180 25.0 0.0 0.0 14.1 352.9 6.7 335.6
1+25 387,989.94 686,296.10 180 25.0 15.2 381.0
Q 1+50 388,014.94 686,296.32 180 25.1 0.8 37.7 14.6 365.5 6.5 3275
c
o 1+75 388,040.12 686,296.55 180 25.0 12.5 311.4
F.1• 2+00 388,064.94 686,296.77 180 24.9 1.2 60.4 11.3 280.8 5.9 294.9
"
2+25 388,089.94 686,296.99 180 25.0 9.0 224.2
2+50 388,114.94 686,297.22 180 25.0 0.4 18.1 7.4 185.5 4.4 219.1
2+75 388,139.94 686,297.44 180 25.0 7.2 180.9
. 34-00 388,164.94 686,297.67 180 27.5 0.2 8.1 5.7 157.2 5.6 155.0
3+30 388,194.94 686,297.94 180 32.3 0.1 3.9 5.2 168.7 5.3 171.5
3+64.5 388,229.44 686,298.25 180 42.3 0.4 15.3 5.4 227.2 4.8 204.1
4+10 388,279.10 686,372.13 156 50.0 0.2 9.1 9.1 453.1 6.4 320.6
4+60 388,326.17 686,389.30 156 50.1 0.0 2.2 4.4 219.7 4.6 229.4
co
c 5+10 388,373.24 686,406.47 156 50.1 0.1 5.2 5.1 255.7 7.1 356.9
c
5+60 388,420.31 686,423.64 156 50.1 0.3 13.7 5.1 253.3 8.9 446.1
6+10 388,467.38 686,440.81 156 49.0 0.5 23.2 2.8 136.8 7.2 351.9
6+60 388,512.37 686,457.21 156 49.1 0.0 0.0 0.9 43.9 1.7 85.0
7+10 388,553.62 686,486.14 145 45.0 0.0 0.0 0.2 9.0 0.5 23.2
7+50 388,548.38 686,525.38 82 44.8 0.0 0.0 0.0 0.0 05 21.2
8+00 388,541.76 686,574.94 82 50.0 0.9 46.3 1.6 81.3 4.5 224.8
8+50 388,535.14 686,624.50 82 50.0 0.9 46.3 4.8 240.6 5.0 252.4 � /
9+00 388,528.52 686,674.06 82 50.0 0.5 23.5 5.2 260.0 4.9 246.1 P/l.
9+50 388,521.91 686,723.62 82 50.0 0.6 28.5 4.8 239.4 3.7 1865
u 10+00 388,515.29 686,773.18 82 345 0.0 0.0 1.2 43.1 0.5 17.8
c 10+19 388,512.76 686,792.09 140 25.0 0.0 0.0 1.0 24.0 0.2 5.4 ��'
� �
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0
i 10+50 388,536.63 686,811.79 140 40.5 0.0 0.0 2.9 118.9 2.7 109.7 _.7'3 JZ UI 3P
11+00 388,575.19 686,843.61 140 50.0 0.0 0.0 0.7 32.8 0.3 16.9 3J
11+50 388,613.75 686,875.44 140 50.0 0.0 0.0 2.0 102.0 0.7 36.7
12+00 388,652.32 686,907.26 140 101.0 0.8 81.5 4.4 445.1 4.2 422.0
16+00 388,736.07 686,848.63 240 25.0 0.4 10.5 4.9 122.8 6.2 154.4
16+50 388,760.89 686,805.22 240 50.0 0.0 0.0 4.8 238.3 5.7 286.3
17+00 388,785.72 686,761.82 240 25 0.2 5.6 4.2 104.1 3.8 95.0 3 i
Section A 144 3,684 2,223
Section 8 53 1,372 1,813 33`2
Section C 242 2,052 2,075 L g•t:;
Totals 439 7,108 6,111 _
.5 / 7
Agenda item#7a
ESA 4350 West Cypress Street Page 1e.esassoc.com
Suite 950
Tampa,FL 33607
813.207.7200 phone
813.207.7201 fax
memorandum
date June 28, 2019
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
The United States Environmental Protection Agency and the 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 TMDLs. The SSAC for
Clam Bay is considered in the context of specific conductance, which is directly related to salinity.
The reason for this is that nutrient concentrations vary with the amount of freshwater influence,
even in watersheds with no human impacts. The Clam Bay NNC criteria are constructed in such
a manner that changes in nutrient concentrations that are likely due to variation in rainfall alone
are identified, so that the focus can remain on changes in nutrient concentrations due to sewage
spill
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
the degree of nutrient enrichment of Clam Bay's waters. 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 percentile prediction limit (Figure 1), and an annual percent
exceedance is calculated to determine the magnitude of exceedances per year. 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 percentile prediction limit
(after being normalized for conductivity) the duration of exceedance is then 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
Agenda item#7a
Page 2 of 7
exceedances are large, then the outcome is "3". The management response for Clam Bay 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. In this manner, the
"health" of Clam Bay is to be assessed annually.
Do 213%of all TN 8,t/or TP
values from a calendar year
No exceed the 90%prediction limit
from the reference WBID?
Outcome0 Yes
213°/v_ Magnitude of X15%
exceedance
Duration of Duration of
exceedance exceedance
1 year >1 year 1 year >1 year
Outcome 1 Outcome 2 Outcome 2 Outcome 3
Figure 1. Clam Bay water quality flow chart.
2
Agenda item#7a
Page 3 of 7
Total Phosphorus
Total Nitrogen Outcome 0 Outcome 1 Outcome 2 Outcome 3
Outcome 0
Outcome 1
Outcome 2
Outcome 3
Figure 2. Management response matrix using outcomes from both TN and TP
evaluation.
Green Response Yellow or Red
evaluation
Hold the
line
Evaluate phytoplankton/ significant
dissolved oxygen (p<0.05)
Not significant response to nutrient
(l)0.05) concentrations
Evaluate water clarity
Not significant response to chlorophyll-a
(x0.05)
Significant(p4.05)
Small difference or
short duration
Identify potential causes Identify potential
and implement
Large difference or causes and
recommended response long duration rncponce,
Figure 3. Management response actions in response to various outcomes.
3
Agenda item#7a
Page 4 of 7
Data Analysis
The analysis conducted below was used to assess the water quality status of Clam Bay during
the months of November 2018 to January 2019. 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.os25s-o.0000328465*Conductivity(Ns))
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).
Results
Over the period analyzed in this memo (November 2018 to January 2019), there were three
TN measurement from the open waters of Clam Bay (from the 9 ambient water quality stations
sampled three times each) which exceeded their Upper Limits for NNC criteria. In the prior
annual report, a total of fifteen (15) ambient water quality values for TN exceeded the
respective TN Upper Limit. In terms of nitrogen, it does not appear that the open waters of
Clam Bay are problematic, at least for the last quarter and this current one.
In contrast, 26 of the 27 TP measurements (96 percent) exceeded their respective Upper
Limits. This frequency of occurrence exceeds the 13 percent threshold shown in Figure 1,
which means that for this quarter continues to have phosphorus concentrations that exceed
the established criteria. The exceedances occurred throughout the open water areas of Clam
Bay and all sampling events In the prior annual report, 67 of 108 samples exceeded NNC
criteria for TP, which indicates that elevated TP concentrations have been prevalent for an
extended period of time.
It should be noted that laboratory detection limits can sometimes come into play when
comparing values against criteria, as detection limits sometimes are such that values have to
be "rounded up" based on minimum detection limits. Based on the results from this time
4
Agenda item#7a
Page 5 of 7
period, and if the frequency of exceedance seen here was to be maintained over the course of
a calendar year, Clam Bay would likely be determined to be impaired for TP.
The TN and TP exceedances are illustrated in Tables 1 and 2. While the TP exceedances
during this quarter are numerous, and are consistent with the widespread elevated
concentrations noted in the 2018 annual report. Since July 2018, TP concentrations have
been elevated throughout the entire Clam Bay system. This widespread pattern of
exceedances had been suggested to be related to tree defoliation and excessive rainfall and
runoff associated with Hurricane Irma. After Hurricane Charley hit Southwest Florida in 2004,
widespread defoliation of vegetation brought about impacts to water quality throughout both
Charlotte Harbor and the Peace River watershed (Tomasko et al. 2006). However, the
persistence of TP exceedances more than a year after the passage of Hurricane Irma is not
consistent with the shorter-term impacts that were recorded after the passage of Hurricane
Charley (Tomasko et al. 2006).
Table 1. Observed TN Exceedances (marked with an "X") at the ambient Clam Bay
surface water sample sites over the period of November 2018 to January 2019. Table
extended to show 12 months of data required for an annual assessment.
Sampling event
Station Nov Dec Jan Feb Mar Apr May Jun Jul Aug Oct
1
2
3 X
4
5
6 X
7
8
9 X
Table 2. Observed TP Exceedances (marked with an "X") at the ambient Clam Bay
surface water sample sites over the period of November 2018 to January 2019. Table
extended to show 12 months of data required for an annual assessment.
Sampling event
Station Nov Dec Jan Feb Mar Apr May Jun Jul Aug Oct
1 X X X
2 X X X
3 X X
4 X X X
5 X X X
6 X X X
7 X X X
8 X X X
9 X X X
5
Agenda item#7a
Page 6 of 7
In addition, water quality data from six of the Clam Bay Outfall monitoring stations were
compared to the proposed downstream protective values (DPV) for Clam 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 1.80 mg/L, respectively (PBS&J
2011). The median and 90th percentile DPVs for TP are 0.10 and 0.25 mg/L, respectively. For
TN, 78 and 39 percent of the values exceeded the median and 90th percentile DPV criteria,
respectively, during the months of November 2018 through January 2019 (Table 3). It should
be noted that a "median" value represents a value where 50 percent of samples would be
expected to be in exceedance. Similarly, it would be expected by chance alone that 10
percent of values would exceed the 90th percentile DPV, vs. the 39 percent of TN values found
here. For TP, 72 percent of values exceeded the median DPV criterion, while 11 percent of
values exceeded the 90th percentile DPV criterion.
Table 3. Percentage of TN or TP concentrations from outfall stations which exceeded
the median or 90th percentile DPV values for stormwater runoff.
DPV Total Nitrogen Total Phosphorus
Median 90th Percentile Median 90th Percentile
Percent of values below 22 61 28 89
Percent of values above 78 39 72 11
Discussion
It should be noted that because this data analysis is not based on a full calendar year of data,
it is only an indicator of the potential for the Clam Bay system to be determined to be out of
compliance with its established water quality criteria (FAC 62-302.531). However, quarterly
status reports can be useful as an early warning system to alert the County of situations where
water quality might be significantly out of compliance with established criteria.
As was previously noted in the 2018 Annual Report, the findings displayed here suggest
phosphorus concentrations in the open waters of Clam Bay are potentially problematic. Within
this quarter, 96 percent of TP values exceeded a threshold value meant to "hold the line" on
nutrient concentrations in the Clam Bay system. However, elevated nutrient concentrations at
outfall sampling locations identified that during this quarter, only 11 percent of TP values from
sampled outfall locations exceeded a criterion that is expected to be exceeded 10 percent of
the time, suggesting that the watershed does not add excessively high TP runoff to Clam Bay.
These findings suggest that elevated TP concentrations in Clam Bay could be due to activities
not in the watershed alone. However, 83 percent of stormwater outfall samples exceeded a
threshold criterion for phosphorus that was only expected to be exceeded 50 percent of the
time.
6
Agenda item#7a
Page 7 of 7
At the outfall locations in contrast to previous reporting periods, concentrations of nitrogen are
slightly elevated, as exceedance rates for the median DPV concentration are greater than what
is to be expected. Despite the elevated TN concentrations in the outfalls, a concurrent impact
on nitrogen in Clam Bay was not observed.
Taken as a whole, the water quality data collected between the months of November 2018 and
January of 2019 suggest that the open waters of Clam Bay have more phosphorus than would
be expected, as 96 percent of samples exceeded the criteria spelled out for Clam Bay in the
State of Florida's Impaired Waters Rule (FAC 62-302.531). For nitrogen, no such concern
currently exists. These results come from sampling events during Southwest Florida's typical
dry season, and results might be expected to differ from results from sampling efforts in the
current wet season.
7
Agenda item#7b
Page 1 of 1
Clam Bay Copper ug/L
Collection Date CBI CB2 CB3 CB4 CB5 CB6 CB7 CB8 CB9 Report Date
6/22/2016 0.862 0.700 0.700 0.700 1.640 2.100 0.700 3.520 1.510 9/8/2016
7/20/2016 0.924 5.330 5.110 5.660 2.470 3.960 4.950 5.710 10.500 9/12/2016
7/20/2016 0.924 6.160 4.700 1.690 2.470 1.830 1.980 1.870 8.360 9/21/2016
8/25/2016 2.000 1.850 1.680 1.470 1.240 1.520 2.250 1.280 8.060 10/4/2016
9/20/2016 1.690 2.280 1.280 1.760 0.751 0.700 0.700 1.030 0.700 11/22/2016
10/12/2016 2.760 2.200 2.130 1.190 2.900 1.860 1.060 0.954 1.310 12/7/2016
11/9/2016 2.340 3.390 2.300 2.250 1.630 1.500 1.180 2.030 1.300 1/16/2017
12/6/2016 2.330 2.930 5.100 2.450 2.390 1.780 1.270 1.880 1.720 3/14/2017
1/19/2017 2.570 3.560 2.110 1.990 0.818 0.800 0.961 1.110 2.020 4/4/2017
2/23/2017 2.510 3.350 1.600 1.120 0.851 0.848 1.500 2.570 2.600 4/24/2017
3/21/2017 7.970 4.080 1.710 1.120 0.894 0.846 1.080 1.090 0.957 6/1/2017
4/18/2017 6.480 8.160 1.620 1.240 0.800 0.956 1.280 1.010 1.100 6/14/2017
5/24/2017 2.840 4.060 4.990 0.800 0.800 0.959 0.800 0.920 0.946 7/6/2017
6/21/2017 3.840 4.240 3.850 0.906 1.200 1.140 1.260 1.110 0.760 8/8/2017
7/13/2017 4.700 2.950 3.800 4.080 2.500 2.440 2.370 2.380 2.210 8/29/2017
8/14/2017 4.290 3.810 3.220 2.650 1.400 1.220 1.470 1.020 0.700 10/10/2017
10/4/2017 2.680 1.270 0.600 0.800 12.600 1.610 0.600 0.600 1/22/2018
11/28/2017 0.700 0.722 2.540 0.700 0.700 0.700 0.700 0.700 0.700 1/22/2018
12/12/2017 1.780 2.250 1.890 0.700 1.210 1.210 1.300 0.728 0.911 3/26/2018
1/8/2018 0.420 1.510 1.690 1.590 0.800 0.809 0.800 0.800 2.400 4/27/2018
2/6/2018 3.400 3.980 2.130 2.420 0.829 1.640 3.920 0.800 0.800 4/30/2018
3/22/2018 5.450 4.890 3.670 2.370 1.010 1.040 1.750 1.010 1.320 5/11/2018
4/4/2018 2.370 3.190 2.380 1.970 1.690 0.848 1.280 1.250 5.160 6/11/2018
5/8/2018 5.490 4.880 2.360 1.090 0.800 1.050 1.270 1.570 1.640 7/2/2018
6/6/2018 3.120 3.320 2.670 0.800 0.800 0.853 0.828 1.080 1.220 7/18/2018
7/17/2018 1.400 1.440 1.600 1.600 2.270 1.600 1.600 1.600 1.600 8/21/2018
8/15/2018 1.500 1.410 1.400 1.400 1.600 1.600 1.600 1.650 1.600 10/8/2018
9/13/2018 1.720 1.960 1.200 1.200 1.400 1.400 1.400 1.600 1.400 10/9/2018
10/15/2018 3.190 4.800 4.400 4.030 1.400 1.400 1.960 1.400 1.400 12/21/2018
11/14/2018 1.750 1.900 1.960 1.600 1.600 1.600 1.600 1.600 1.600 2/28/2019
12/12/2018 4.480 2.790 2.400 1.820 1.600 1.600 1.600 1.600 1.600 2/28/2019
1/14/2019 3.150 2.740 2.100 1.880 1.600 1.600 1.600 1.600 1.600 5/3/2019
2/25/2019 3.420 2.470 2.000 1.940 1.600 1.600 1.600 1.600 1.600 5/3/2019
3/25/2019 1.830 3.090 1.600 2.730 1.600 1.600 1.600 1.600 1.600 5/14/2019
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Channels through the Mangroves
There are thirteen miles of channels through the mangroves of Clam Bay. These
channels ensure that sea water flows through the mangroves and drains back into
the Gulf leaving the right amount of salinity for our mangroves to thrive. The
construction of the hand dug flushing channels was done in 1998 allowing the
mangroves to reestablish after a severe die off. There was concern expressed in
the Clam Bay Committee meetings in 1999 that the problem was the excessive
amount of fresh water and fertilizer running in to the mangroves. The problem
went on to be diagnosed as insufficient saltwater from the gulf getting through to
the mangroves. In 1998 starter islands were created and planted with additional
mangroves to reinvigorate decimated areas. Over time and with constant
attention, the mangroves recovered, grasses reestablished, and crabs returned
and burrowed into the soil aerating it and bringing a healthy mangrove
watershed.
After Hurricane Irma, there was devastating destruction stripping most of the
leaves off the branches and breaking many branches. Among the action items
that were immediately put in place was a more extensive clearing of fallen trees
which were blocking the channels. Today, there is a map of all those channels.
Annually, Turrell Hall & Associates, a consultant hired and managed by the Pelican
Bay Services Division (PBSD), walks through the targeted channels removing any
significant obstruction— and any plastic bottles, cups and other people related
paraphernalia that has blown there. The process is manual, using a shovel to
maintain the twelve-inch depth. This summer additional hand dug channels will
be concentrated in the TH-5 area which is located ...... Downed trees are
generally left to naturally decay. Drones and aerial photographs are also used to
diagnose and track specific sectors where mangroves are failing to thrive.
These are only a few of the tools in the Clam Bay Natural Resource Protection
Area (NRPA) Management Plan process begun in 1998 and reviewed and updated
in 2014. We will continue to learn about the other tools and techniques used to
maintain and enhance the health of our vital and beautiful mangroves and Clam
Bay.
Five years later, how are we doing against the Clam Bay Natural Resource Protection Area (NRPA) Plan created
in November 2014?One of the five objectives included: Ensure the estuary has adequate tidal and freshwater flows to
maintain ecological health within the Clam Bay NRPA. Nature changes the opening, particularly driven by high pressure
weather events including, but not limited to hurricanes and storms.
There are many mechanisms used to assess the health of Clam Pass.One is the regular quarterly(?)aerial
photographing of the bay with a focus on the channel.. who then
Turrell, Hall& Associates, Inc. a firm in the fields of marine environmental and coastal engineering has been
the lead consultant for, ongoing restoration and maintenance for the Clam Bay ecosystem since 1998. The
system consists of a series of shallow estuarine lagoons with approximately 500 acres of mangrove forested
areas, open shallow water areas, sea grass beds, dune and beach habitat. - _• . - •- - - .
system is currently stressed; approximately 40 50 acres of black mangroves have been reported dead or dying
Given the size of the system a combination of ground truthing and aerial photography has been used to
accurately and efficiently map and catalogue vegetative communities in Clam Bay. Efforts were focused on
restoration activity success could be measured.
The aerial survey was conducted by Park Coastal Surveying and compared with pre-construction survey from
April 2018.
The photographs are then analyzed and measured against a prior shots and against an established plan agreed
upon with federal, state and local entities (such as SFWM, CAC, ?). By monitoring changes we are able to
anticipate needs for dredging or other actions to ensure the flow of salt water into the mangroves.
There are two phots shown here to highlight the process and evaluation.
Overall the survey indicates a healthy inlet condition that is able to maintain flow through section A with
capacity remaining in sections B and C to accommodate additional shoaling, reported D. Mohamed Dabees of
Humiston&Moore Engineers.
Clam Pass is a small wave dominated inlet on the southwest coast of Florida that provides a tidal connection to 500
acres of the wetland preserve of Clam Bay Natural Resource Protection Area(NRPA). This preserve includes several
interconnected bays surrounded by extensive areas of mangrove wetlands. The preserve is a pristine environmental
resource that is collectively known as Clam Bay. Clam Pass has gone through periods of inlet migration as well as
closure,because the relatively small tidal prism for Clam Bay provides critical balance between tidal energy and littoral
process at the inlet channel.
Humiston&Moore Engineers provides professional engineering services to Pelican Bay Services Division of Collier
County, Florida for Clam Pass and Clam Bay. Humiston& Moore Engineers provided engineering services to assist
Turrell Hall &Associate in the development of the Clam Bay NRPA management plan of 1998 and the updated plan
of 2014. The engineering services included the development of design criteria for the inlet stability and conditions for
maintenance dredging to maintain hydraulic efficiency and avoid potential inlet closure including.The implementation
of the NRPA management plan includes various monitoring to maintain the health of the eco system. In addition to
the ecological and biological monitoring of the bay system and its function as a protected environmental resource,the
monitoring program includes hydraulic and physical monitoring of the inlet and bay system to monitor the stability of
the pass and assess maintenance requirements. Monitoring of the hydraulic and physical conditions of the Clam Bay
system continues according to the updated NRPA management plan. The hydraulic monitoring includes continuous
water level and tidal data collection at 4 locations within the bay system.