PBSD MSTBU Clam Bay Committee Agenda 09/06/2018 PELICAN BAY SERVICES DIVISION
Municipal Service Taxing and Benefit Unit
NOTICE OF PUBLIC MEETING SEPTEMBER 6, 2018
THE CLAM BAY COMMITTEE OF THE PELICAN BAY SERVICES DIVISION WILL
MEET AT 1:30 PM ON THURSDAY, SEPTEMBER 6 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 07/12/18 meeting minutes
4. Audience comments
5. Clam Bay
a. Update on monitoring
b. Update on THA assessment of debris removal and hand-dug channel
maintenance
c. Canoe trail marker 12
d. Draft update for October PB Post
6. Clam Pass
a. H&M August tidal ratio report
b. August aerial photos
c. Bathymetric survey results for annual report
7. Water quality
a. Tomasko Clam Bay WQ reports for Nov. 2017 —April 2018
b. Copper results
c. Proposal for copper sediment testing
d. Suggested changes in upland pond WQ testing and report
8. Annual Reports
a. Clam Bay Tidal Analysis and Bathymetric reports due December 21, 2018
b. Water Quality report due February 15, 2019
c. Documentation of rookery for annual WQ report
9. Next meeting: January 3, 2019
10. Adjournment
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ITEM TO ADDRESS THE BOARD. THE BOARD WILL SOLICIT PUBLIC COMMENTS ON SUBJECTS NOT ON
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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.
8/30/2018 11:26 AM
PELICAN BAY SERVICES DIVISION
CLAM BAY COMMITTEE MEETING
JULY 12,2018
The Clam Bay Committee of the Pelican Bay Services Division met on Thursday, July 12 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 Bohdan Hirniak
Susan O'Brien, Chairman Rick Swider
Pelican Bay Services Division Staff Mary McCaughtry, Operations Analyst
Neil Dorrill, Administrator (absent) Lisa Jacob, Assoc. Project Manager (absent)
Marion Bolick, Operations Manager (absent) Barbara Shea, Recording Secretary
Also Present Mike Shepherd, PBSD Board
Jennifer Bobka, Earth Tech Jeremy Sterk, Earth Tech
Tim Hall, Turrell, Hall & Associates Trent Waterhouse, PBF
APPROVED AGENDA (AS PRESENTED)
1. Roll call
2. Agenda approval
3. Approval of 05/03/18 meeting minutes
4. Audience comments
5. Clam Bay
a. Update on hand-dug channel maintenance
b. Update on exotic maintenance
c. Canoe trail marker 12
6. Clam Pass
a. H&M June tidal ratio report
b. June aerial photos
c. FDEP requiring idle speed signage
7. Water quality
a. THA contract for WQ in 2018
b. Tomasko report on Nov. 2017-April 2018 Clam Bay WQ results
c. Copper results
d. Copper sediment testing in Upper Clam Bay
e. Documentation of rookery
f. Using hydrogen peroxide algaecide in swale on east side of berm
g. Upland pond WQ report
8. Next meeting: September 6
9. Adjournment
1
Pelican Bay Services Division Clam Bay Committee Meeting
July 12, 2018
ROLL CALL
All members were present and a quorum was established
AGENDA APPROVAL
Mr.Hirniak motioned,Ms.O'Brien seconded to approve the agenda as presented.
The motion carried unanimously.
APPROVAL OF 05/03/18 MEETING MINUTES
Mr. Hirniak motioned, Ms. O'Brien seconded to approve the 05/03/18 meeting
minutes as amended. The motion carried unanimously.
AUDIENCE COMMENTS
None
CLAM BAY
UPDATE ON HAND-DUG CHANNEL MAINTENANCE
Mr. Sterk commented that his firm, Earth Tech, has recently completed the annual hand-
dug channel maintenance and IRMA debris removal work. Ms. McCaughtry commented that she
is about to issue a notice to proceed to Turrell, Hall &Assoc. to review ETE's work. When THA
completes the review, a report will be provided to PBSD staff. Mr. Sterk provided the committee
with before and after photos of the channels where maintenance work was completed, as well as a
map documenting every area of completed work(through GPS tracking).
UPDATE ON EXOTIC MAINTENANCE
Mr. Sterk reported a discovery of one patch of Brazilian Pepper(an invasive exotic),while
working on the hand-dug channel maintenance field work. This area of exotics will be scheduled
for removal.
CANOE TRAIL MARKER 12
Mr. Sterk commented that canoe trail marker 12 remains on the County's list of markers
to be replaced.
CLAM PASS
H&M JUNE TIDAL RATIO RESULTS
Ms. O'Brien commented that the June tidal ratios are above .7 and look excellent.
JUNE AERIAL PHOTOS
Mr. Sterk provided the June Clam Bay aerial photos for review by the committee. Mr. Tim
Hall, Turrell, Hall, & Assoc., commented on new growth areas of mangroves.
FDEP REQUIRING IDLE SPEED SIGNAGE
Ms. O'Brien commented that she will follow up with Mr. Dorrill on an e-mail from Mr.
Dave Cook to Mr.Dorrill,which suggested that a condition of the FDEP Clam Bay permit requires
that there be idle speed and no wake. At the May Clam Bay Committee meeting, Mr. Dorrill had
commented that he would discuss this issue with Dr. Dabees.
2
Pelican Bay Services Division Clam Bay Committee Meeting
July 12,2018
WATER QUALITY
THA CONTRACT FOR WQ WORK FOR 2018
Ms. O'Brien commented that a new contract for Clam Bay water quality reports is now in
place with Turrell, Hall & Assoc. Mr. Hall will review the Clam Bay Management Plan to
determine whether four quarterly water quality reports are required, and then coordinate reporting
with Dr.Dave Tomasko (Environmental Science Associates). Ms. O'Brien requested that the first
report be available no later than Sept. 6.
COPPER RESULTS
Ms. O'Brien commented that copper results look good, showing just 7 out of 63
exceedances so far this year.
COPPER SEDIMENT TESTING IN UPPER CLAM BAY
Mr. Tim Hall commented on his report on recent copper sediment testing in Upper Clam
Bay which shows large variances in copper levels in the samples tested. He noted that none of the
samples tested show copper levels in the "danger zone" (at a level where the biological system is
considered poisoned). Mr. Hall recommended adding additional Upper Clam Bay sample points
to the next system-wide sediment test.
Mr. Shepherd questioned whether the FDEP could require a dredge of part of the Clam
Bay estuary, and if so, what entity would be financially responsible. Ms. O'Brien suggested the
likelihood of a cost shared project by the PBSD, the PBF, and the County. Mr. Hall commented
that the FDEP could force remedial work. Mr. Sterk commented that the FDEP could force
dredging of upland lakes. Ms. O'Brien commented on the tremendous progress that the PB
community has made,as exemplified by 48%of copper sample exceedances in 2012 and just 16%
exceedances in 2017 (with a goal of under 15%in any given year).
DOCUMENTATION OF ROOKERY
Mr. Hall commented on a recent conversation with Dr. Tomasko, who recommended
keeping records/documentation on the number of nests and photos of the rookery in Upper Clam
Bay. These could be used to support a response to an FDEP inquiry on high phosphorus levels,
which would show these levels to be a natural result of the existence of the rookery.
USING HYDROGEN PEROXIDE ALGAECIDE IN SWALE ON EAST SIDE OF
BERM
Mr. Hall commented that hydrogen peroxide is an effective algaecide. However,removing
algae on the east side of the berm will cause an increase in nutrients entering Clam Bay.
UPLAND POND WQ REPORT
Ms. O'Brien commented that our contract with CH2MHi11 for upland pond water quality
reports has expired and suggested the possibility of reducing the number of reports and/or the
number of samples. Mr. Hall recommended the continuation of the reports and will consult with
Dr. Tomasko to obtain his opinion on reducing the parameters. The committee commented in
favor of continuing these reports.
PHOTOS SENT TO THE COUNTY MANAGER'S OFFICE: AREA OF MANGROVE
DIE-OFF
3
Pelican Bay Services Division Clam Bay Committee Meeting
July 12,2018
Mr. Sterk reported that a PB resident sent photos of a mangrove die-off area in Clam Bay
to the County Manager's Office. Mr. Sterk commented that this die-off is a result of Hurricane
Irma.
NEXT MEETING:
By consensus,the committee agreed that the next meeting of the committee would be held
on September 6 at 1:30 p.m. Mr. Swider commented that it is critical for Ms.Jacob and Mr.Bolick
to attend this meeting.
ADJOURNMENT
rTIle meeting was adjourned at 2:56 p.m.
Susan O'Brien, Chairman
Minutes approved F 1 as presented OR [ 1 as amended ON 1 1 date
4
Agenda item#5d
Page 1 of 2
DRAFT
Clam Bay Update (for October Pelican Bay Post)
Post Irma
A year after Irma some encouraging signs of regrowth, including new seedlings, in the mangrove
forest have been noted. Hurricane Irma did considerable damage to the mangroves, especially on the
east and north sides of Clam Bay. The Pelican Bay Services Division's (PBSD) consultant, Earth Tech
Environmental, noted these encouraging developments during its biannual monitoring of the
mangroves. Hopefully these signs of recovery will continue to be noted, but full recovery may be years
away. Extensive work was done in May and June to remove Irma-related debris from Clam Bay
waterways and hand-dug channels. The removal of dead mangrove branches and trees from Clam Bay
is not recommended because their presence can enhance seedling regeneration.
2015 Mangrove Die-off
Another encouraging sign from recent Clam Bay monitoring is that the 2015 die-off of some
mangroves in Upper Clam Bay has stabilized and is not expanding. The monitoring of this area will also
continue so any new concerns can be promptly addressed.
Water Quality
In 2012 the Florida Department of Environmental Protection found Clam Bay to be impaired for
copper, based on 12 of 25 water samples (48%) exceeding the state standard for copper. In September
2013 PBSD stopped using copper sulfate in water management ponds in Pelican Bay(PB) and asked PB
associations to do the same. Per the 2017 Annual Water Quality Report, only 16%of the water samples
in Clam Bay exceeded the state standard for copper. An acceptable percentage is 15%so the copper
level in Clam Bay is not quite where it needs to be, but considerable progress has been made in the last
five years to reduce unacceptable levels of copper in Clam Bay.
The 2017 Annual Water Quality Report found that about 30%of water samples in Clam Bay
exceeded the state standard for total phosphorus, significantly more than the allowable 10%. The
highest instances of exceedances were from February to May when wading birds may be nesting in
Upper Clam Bay. This may be a significant source of the high phosphorus level so further documentation
of bird activity in this rookery will be done.
Clam Pass
The dredging of Clam Pass was completed on May 10 with about 8250 cubic yards of sand
removed. Since the dredging event,the tidal ratios, based on monthly data from tidal gauges in Clam
Bay, are very good, showing good flow into and out of Clam Pass.
Additional information and questions
The 2017 annual reports on Clam Bay monitoring, Water Quality, and Physical and Tidal
Monitoring are available on PBSD's home page at PelicanBayServicesDivision.net. PBSD's Clam Bay
Committee typically meets every other month, and its meetings are posted on the calendar on PBSD's
home page. Please send questions or concerns about Clam Bay to the email link on PBSD's home page.
Submitted by PBSD's Clam Bay Committee: Bohdan Hirniak, Susan O'Brien, and Rick Swider
Agenda item#5d
Page 2 of 2
I-Iumiston & Moore Engineers I ClamPass-TIDE Agenda item#6a
Page 1 of 2
Clam Pass Tide Monitoring -Click here for Maintenance Dredging Project details
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Humiston & Moore Engineers I ClamPass-TIDE Agenda item#6a
Page 2 of 2
Gaae/Gulf Mean Tide Ratios-2016
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Definitions:
Mean Tide Ratio:ratio of tide amplitude of gages over the tide amplitude from the Gulf of Mexico,averaged over a month.This
ratio is representative of the pass's effectiveness in flushing water from the bay. The lower the ratio, the less efficient is
flushing,indicating material accumualting in the pass.
Mean Low Tide Lao: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 efficient is flushing,indicating material accumulating in the pass.
Background,
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.
•
littps://www.humistonandmoore.com/clanlpass-tide 9/4/2018
Agenda item#7a-1
Page 1 of 36
4350 West Cypress Street
Suite 950
Tampa,FL 33607
813.207.7200 phone
813.207.7201 fax
memorandum
date August 13, 2018
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 (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 TMDLs. The SSAC for
Clam Bay is considered in the context of salinity due to the variability in nutrient concentrations
that can be due to changes in freshwater inflow, rather than changes in nutrient concentrations
alone. 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 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
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
Agenda item#7a-1
Page 2 of 36
magnitude and duration of the 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.
Figure 1. Clam Bay water quality flow chart.
11e. 13%ofall TN&/orTP
values froma calendar year
N o exceed the 90%prediction limit
from the reference WRIT ?
Outcome0 Yes
?13°l0 Magnitude of ?1.5°
exceedance
Duration of Durationof
exceedance exceedance
1 year >1 year 1 year >1 year
Outcome I Outcome 2 Outcome2 Outcome 3
2
Agenda item#7a-1
Page 3 of 36
Figure 2. Management response matrix using outcomes from both TN and TP
evaluation.
Total Phosphorus
Total Nitrogen Outcome 0 Outcome 1 Outcome 2 Outcome 3
Outcome 0
Outcome I
Outcome 2
Outcome 3
Figure 3. Management response actions in response to various outcomes.
green Response Yellow or Red
evaluation
ltolco t'�r
Evaluate phytoplankton/ significant
dissolved oxygen (p<o.os)
Not significantJ_.__. response to nutrient
(p-o,os) concentrations
Evaluate water clarity
Not significant response to chlorophyll-a
(p•-o.os)
Significant(p<1.O5)
Small difference or
short duration
Identify potential causes
and implement Identify potential
l
Large di
recommendedreslaorlse ffereniecauses or
long dui ation responses
3
Agenda item#7a-1
Page 4 of 36
Data Analysis
The analysis conducted below was used to assess the water quality status of Clam Bay during
the months of November 2017 to January 2018. 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(-1.06256-0.0000328465`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).
Results
Over the period analyzed in this memo (November 2017 and January 2018), there were no 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 three (3) 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, 10 of the 27 TP measurements (38 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, at least, phosphorus concentrations appear to be
problematic. The majority of exceedances occurred during the November 2017 sampling
event (6 event exceedances were reported). These exceedances could be attributed to the
defoliation of trees associated with the passing of Hurricane Irma in September 2017;
however, in the prior annual report, 33 of 98 samples exceeded NNC criteria for TP, which
indicates that although Irma may have exacerbated water quality problems, such problems
(elevated levels of TP) preceded the passage of that storm.
4
Agenda item#7a-1
Page 5 of 36
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
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 10 TP exceedances are illustrated in Table 1. The fairly widespread pattern of
exceedances in November 2017 are potentially related to the 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). In
Clam Bay, most of the exceedances of the TP criteria were observed in portions of Clam Bay
with the most restricted circulation (Upper and Inner Clam Bay) and exceedances decreased
from November to December and then again to January. These results could be indicative of
the impact and subsequent recovery of water quality after the passage of Hurricane Irma.
Table 1. Observed TP Exceedances (marked with an "X") at the ambient Clam Bay
surface water sample sites over the period of November 2017 to January 2018.
Sampling event
Station Nov Dec Jan Feb Mar Apr May Jun Jul Aug Oct
1 X X X
2 X X
3 X X
4
5 X
6 X
7 X
8
9
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, 47 and 6 percent of the values exceeded the median and 90th percentile DPV criteria,
respectively, during the months of November 2017 through January 2018 (Table 2). 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 6 percent of TN values found
here. For TP, 94 percent of values exceeded the median DPV criterion, while 6 percent of
values exceeded the 90th percentile DPV criterion.
5
Agenda item#7a-1
Page 6 of 36
Table 2. 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 53 94 6 94
Percent of values above 47 6 94 6
Discussion
It should be noted that because this data analysis is not based on a full calendar year of data,
it is 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 has been noted in the 2017 Annual Report, the findings displayed here suggest phosphorus
concentrations in the open waters of Clam Bay are potentially problematic. Within this quarter,
38 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 6 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, 94 percent of stormwater outfall samples exceeded a
threshold criterion for phosphorus that was only expected to be exceeded 50 percent of the
time.
At the outfall locations, concentrations of nitrogen do not appear to be overly problematic, as
exceedance rates for the median DPV concentration are mostly in-line with expectations. The
highest TN values were consistent with what was expected, as only 6 percent of samples
exceeded a criterion that was only expected to be exceeded 10 percent of the time.
Taken as a whole, the water quality data collected between the months of November 2017 and
January of 2018 suggest that the open waters of Clam Bay have more phosphorus than would
be expected, as 38 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 included the after effects of the passage of an extreme tropical event, the
landfall of Hurricane Irma in nearby Everglades City.
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Agenda item#7a-2
Page 1 of 36
memorandum
date August 27, 2018
to Tim Hall, Turrell, Hall and Associates, Inc.
from David Tomasko, Ph.D.
Emily Keenan, M.S.
subject Quarter 2: Clam Bay NNC SSAC evaluation
Background
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 TMDLs. The SSAC for
Clam Bay is considered in the context of salinity due to the variability in nutrient concentrations
that can be due to changes in freshwater inflow, rather than changes in nutrient concentrations
alone. 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 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
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
Agenda item#7a-2
Page 2 of 36
magnitude and duration of the 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.
Figure 1. Clam Bay water quality flow chart.
bo 3%of all TN&forTP
values from a calendar year
N0 exceed the 90 pr iictien limit
from the reference MID?
Outcome f Yes
?13% Magnitude of >15°%
exceedance
Duration of Duration of
exceedance exceedance
1 year >1 year 1 year >1 year
Outrmne1 Outeomea Outcome 2 Outeome:t
Agenda item#7a-2
Page 3 of 36
Figure 2. Management response matrix using outcomes from both TN and TP
evaluation.
Total Phosphorus
Total Nitrogen Outcome 0 Outcome 1 Outcome 2 Outcome 3
Outcome 0
Outcome 1
Outcome 2
Outcome 3
r
if
Figure 3. Management response actions in response to various outcomes.
Green Response Yellow or Red
evaluation
Hold the
tie
Evaluate phytoplanton/ Significant
dissolved oxygen (p<0,05)
Not significant response to nutrient
(1)"0.05) concentrations
Evaluate water clarity
Not significant response to chlorophyll-a
(p-0.05)
Significant(pc a.05)
I
Small difference or
identify potential causes i short duration
ILit ri f,1potential
and implement
Largo difference or causeS 3 flcl
recommended response long duration responses
Agenda item#7a-2
Page 4 of 36
Data Analysis
The analysis conducted below was used to assess the water quality status of Clam Bay during
the months of February 2018 to April 2018. 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(-1.06256-0.0000328465*Conductivity(ps))
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 (February 2018 to April 2018), there was one TN
measurement from the open waters of Clam Bay (from the 9 ambient water quality stations
sampled three times each) which exceeded the respective Upper Limits. In the prior quarter
report, no 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, 15 of the 27 TP measurements (55 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, at least, phosphorus concentrations appear to be
problematic. The majority of exceedances occurred during the March and April 2018 sampling
events (7 and 6 event exceedances were reported, respectively).
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
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.
Agenda item#7a-2
Page 5 of 36
The 15 TP exceedances are illustrated in Table 1. The fairly widespread pattern of
exceedances in March 2018.
Table 1. Observed TP Exceedances (marked with an "X") at the ambient Clam Bay
surface water sample sites over the period of November 2017 to April 2018.
Sampling event
Station Nov Dec Jan Feb Mar Apr May Jun Jul Aug Oct
1 X X X X X X
2 X X X X X
3 X X X X
4 X X
5 X X X
6 X X
7 �, X X
8
9 X
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, 50 and 19 percent of the values exceeded the median and 90th percentile DPV criteria,
respectively, during the months of February through April 2018 (Table 2). 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 6 percent of TN values that exceeded the 90th
percentile value for results displayed here. For TP, 63 percent of values exceeded the median
DPV criterion, while 6 percent of values exceeded the 90th percentile DPV criterion.
Table 2. 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 50 81 38 94
Percent of values above 50 19 63 6
Agenda item#7a-2
Page 6 of 36
Discussion
It should be noted that because this data analysis is not based on a full calendar year of data,
it is 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 has been noted in the 2017 Annual Report, the findings displayed here suggest phosphorus
concentrations in the open waters of Clam Bay are potentially problematic. Within this quarter,
55 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 6 percent of TP values from sampled
outfall locations exceeded a criterion that is expected to be exceeded 10 percent of the time.
Also, 63 percent of stormwater outfall samples exceeded a TP threshold criterion that was only
expected to be exceeded 50 percent of the time.
At the outfall locations, concentrations of nitrogen do not appear to be overly problematic, as
exceedance rates for the median DPV concentration are mostly in-line with expectations. The
highest TN values were slightly more frequent with what was expected, with 19 percent of
samples exceeded a criterion that was only expected to be exceeded 10 percent of the time.
Taken as a whole, the water quality data collected between the months of February through
April of 2018 suggest that the open waters of Clam Bay have more phosphorus than would be
expected, as 55 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.
The prior quarterly sampling period (November 2017 to January 2018) included months that
included sampling events after the landfall of Hurricane Irma, in September of 2017. The
passage of that hurricane was thought to have potentially been associated with the elevated
levels of TP in Clam Bay. However, the results from this sampling event show evidence of
even greater rates of exceedance of TP criteria, which does not support the suggestion that
Hurricane Irma was the primary reason behind exceedances in the prior quarter.
As the rate of exceedance of TP criteria was actually greater in the open waters of the bay
(55%) than rates of exceedance of criteria for runoff into the bay (i.e., 63 vs. 50% expected
exceedance of median DPV, and 6 vs. 10% expected exceedance of 90th percentile DPV) it is
possible that phenomena in the open waters of the bay are equally important to the
exceedance in the bay as is the watershed itself. For example, the influence of birds and their
roosting and nesting behavior could be involved with elevated levels of TP in the open waters
of Clam Bay. An effort to compile known bird counts should be conducted, to determine if the
exceedances for TP are due to human activity in the watershed, or a natural, and welcome,
consequence of a potentially rebounding wading bird population.
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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
Agenda item#7d
Page 1 of 2
TECHNICAL. MEMORANDUM Cli •
Pelican Bay Stormwater Lakes Water Quality Monitoring
Program: August 2017 Sampling Event Data Review
PREPARED FOR: Pelican Bay Services Division
PREPARED DY: CH2M HULL
DATE: 11/16/2017
PROJECT NUMBER: 688446
Introduction
Pelican Bay,a 2,300-acre residential community in Naples,Florida,is located adjacent to a 570-acre
mangrove preserve area known as Clam Bay.This community is served by a stormwater management
system consisting of 63 stormwater lakes designed to attenuate stormwater runoff.The Pelican Bay
Stormwater Lakes are distributed among six drainage basins which deliver stormwater runoff to the west to
Clam Bay(Figure 1).
The Pelican Bay Services Division(PBSD)is currently conducting quarterly surface water quality monitoring
at 29 of the 63 stormwater lakes.The twenty-nine lakes and the reclaimed water source were selectively
chosen for monitoring based on demonstrated elevated concentrations of copper for the period of record
and are listed in Table 1.This technical memorandum(TM)summarizes the stormwater lake water quality
data collected by PBSD during August 2017 which is the fourth and final fiscal year 2017 event. in addition,a
comparison of these data relative to historical water quality data gathered since November 2011 is also
provided.
Appendix A presents a summary of the water quality results for all of the parameters analyzed by the Collier
County Pollution Control laboratory In August 2017.The chain of custody forms for the samples collected in
August 2017 are provided in Appendix B,and Appendix C provides the entire laboratory report.A portion of
the laboratory data was missing due to Hurricane Irma affecting laboratory operations.This resulted in the
loss of only certain nitrogen parameters but did not affect other portions of the laboratory results.
August 2017 Water Quality Data Summary
On August 22,2017,PBSD collected samples at the 29 stormwater lake monitoring stations and the
reclaimed water source as shown in Figure 1.Surface water grab samples were collected and submitted to
Collier County Pollution Control laboratory for analysis of the following parameters:
o Nitrate-Nitrite
• Ammonia
• Total Kjeldahl Nitrogen(TKN)
6 Ortho Phosphate
o Total Phosphorus(TP)
• Total Suspended Solids(TSS)
• Hardness
• Arsenic
• Copper
• Zinc
Concurrent with the collection of the surface water quality grab samples,pH and conductivity were
measured at each sampling location.
Agenda item#7d
Page 2 of 2
PELICAN BAY STORLtWATER LAKES WATER QUALITY MORITOR1UO PROGRAM.AUGUST 2017 SAMAUNO EVENT DATA REVIEW
TABLE 1
Water Sampling Locations of 29 Stormwater Lakes and Reclaimed Water Source
Pelican Day Stormwater Lakes Water Quality Monitoring Program:August 2017 Data Review
Basin Lake Station Station Basin Lake Station Station
No. Number ID Name No. Number ID Name
1 3 1-3 M1D 4 5 4-2 Bay 2
6 1-4 Crayton 2 4-4 Bay4
7 1-5 Registry S 12 4-6 Crescent
Swale 1-6 Heron 8 4-7 Pelican 6
2 1 2-1 Ridgewood Pk 14 4-8 Coco Bay
5 2-2 George N 11 4-10 Pelican 3
3 2-3 George W 5 1 5-1 Hammock Oak
12 2-4 Club 4 2 5-2 L Ambience
7 2-5 Club 7 8 5-5 Breakwater S
13 2-6 Lugano 11 5-7 Bay Colony EN
3 2 3-1 Laurel Oaks 12 5-8 Bay Colony
WN
6 3-4 Pelican 9 15 5-10 Viscaya
8 3-5 interiochen 6 2 6-2 Remington
9 3-6 Valencia (2) N/A RC Reclaim Water
7 3-8 Pelican 1
5 3-9 Club9
Nitrogen Concentrations
Nitrogen monitoring in the Pelican Bay stormwater lakes typically consists of analyses of the nitrogen
species that make up total nitrogen including nitrate-nitrite,ammonia,and TKN.Because this event was
affected by the hurricane,only ammonia and nitrate-nitrite species were reported for Basins 1 through 4,
and no nitrogen samples were analyzed for Basins 5 and 6. Figure 2 presents the ammonia and nitrate-
nitrite concentrations for these basins.These values are similar to previous events at Pelican Bay.However,
these concentrations represent only a small fraction of the nitrogen species that make up total nitrogen.
Organic nitrogen has typically been the largest fraction within the Pelican Bay lakes but these data could not
be determined with the missing data from the laboratory for these 4 basins.
Phosphorus Concentrations
Phosphorus monitoring in the Pelican Bay Stormwater Lakes consists of analysis of two forms of
phosphorus,orthophosphate and total phosphorus(TP).Orthophosphate represents the inorganic form of
phosphorus.Organic phosphorus is calculated as the difference between the TP and orthophosphate
concentrations.Mean concentrations for each drainage basin were calculated for each phosphorus species,
based on the August 2017 data. Figure 3 compares the average TP concentration for each basin and the
relative contributions of each form of phosphorus to the basin mean.
Average TP in all basins ranged from approximately 0.08 to 0.28 milligrams per liter(mg/L).Basin 3 had the
highest average TP concentration(0.28 mg/L)while Basin 1 had the lowest average(0.08 mg/L).The highest
single sample TP value(0.46 mg/L)was measured at station 3-09(Basin 3,Lake No.5)and the lowest single
sample value(0.04 mg/L)at station 1-06(Basin 1,Swale).The last eight events showed similar results for
Basins 1,2,3,4 and 5,with the highest average TP concentrations consistently occurring in Basin 3 at all
events except for the last two previous events where Basin 6 had the highest value.Basin 6 is represented
by a single value at station 6-02(Basin 6,Lake No.2),and cannot be averaged.In contrast to the last two
3