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PBSD MSTBU Clam Bay Committee Agenda 07/12/2018 PELICAN BAY SERVICES DIVISION Municipal Service Taxing and Benefit Unit NOTICE OF PUBLIC MEETING JULY 12, 2018 THE CLAM BAY COMMITTEE OF THE PELICAN BAY SERVICES DIVISION WILL MEET AT 1:30 PM ON THURSDAY, JULY 12 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 05/03/18 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 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://PELICANBAYSERVICESDIVIS I ON.NET. 07/05/2018 1:43 PM PELICAN BAY SERVICES DIVISION CLAM BAY COMMITTEE MEETING MAY 3,2018 The Clam Bay Committee of the Pelican Bay Services Division met on Thursday, May 3 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 Lisa Jacob,Associate Project Manager Marion Bolick, Operations Manager Barbara Shea, Recording Secretary Also Present Mike Shepherd, PBSD Board Jennifer Bobka, Earth Tech Jeremy Sterk, Earth Tech Marielle Kitchener, Turrell, Hall &Associates Trent Waterhouse, PBF APPROVED AGENDA (AS AMENDED) 1. Roll call 2. Agenda approval 3. Approval of 03/08/18 meeting minutes 4. Audience comments 5. Clam Bay a. Update on March mangrove monitoring b. Rookery photos/videos c. Bee boxes d. Debris removal and hand-dug channel maintenance e. Update on exotic maintenance f. Canoe trail marker 12 g. Update modems on tidal gauges (add-on) 6. Clam Pass a. Update on dredging b. H&M April tidal ratio results c. FDEP requiring idle speed signage 7. Water quality a. Proposal for copper sediment testing in Upper Clam Bay b. Copper results c. Upland pond WQ reports d. Data needed for Tomasko WQ report e. Contract for THA WQ work for 2018 f. Other 8. Next meeting: July 12, 17, or 23 9. Adjournment 1 Pelican Bay Services Division Clam Bay Committee Meeting May 3,2018 PBSD BOARD MEMBER,MR. RICK SWIDER,WAS WELCOMED AS A NEW MEMBER TO THE CLAM BAY COMMITTEE 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 amended, with the addition of item#5g. The motion carried unanimously. APPROVAL OF 03/08/18 MEETING MINUTES [-- Mr. Hirniak motioned, Ms. O'Brien seconded to approve the 03/08/18 meeting minutes as amended. The motion carried unanimously. AUDIENCE COMMENTS Mr. Trent Waterhouse, PBF board member, commented on (1) the recent motion filed by the PBF with the judge to get the lawsuit (against FWC to obtain a Manatee Protection Zone designation) remanded to the lower courts to obtain a decision, (2) plans by Mr. Gary McAlpin, Collier County Manager of Coastal Management Programs, to install four signs (idle or slow speed) in Outer Clam Bay, and (3) comments by Mr. McAlpin indicating that the County has no plans for manatee signage in Clam Bay until the PBF lawsuit is resolved. CLAM BAY UPDATE ON MARCH MANGROVE MONITORING Mr. Sterk,consultant with Earth Tech,commented on the results of the March semi-annual mangrove monitoring,which showed that a majority of the plots were relatively stable. However, additional dead trees were observed,considered to be"after-effects"of Hurricane Irma. Mr. Sterk noted two out of the 21 plots as areas of concern. ROOKERY PHOTOS/VIDEOS Mr. Sterk provided drone photos of the rookery in Upper Clam Bay near Station #8, and suggested the high density of nests could be the source of high phosphorus levels in water quality data in this area. Ms.Marielle Kitchener, consultant with Turrell Hall&Assoc.,offered to contact Dr. Tomasko (CH2MHi11)to determine a"suggested method of documentation" of the nests. BEE BOXES Ms. O'Brien commented that the PBF is not interested in installing bee boxes. DEBRIS REMOVAL AND HAND-DUG CHANNEL MAINTENANCE Mr. Sterk commented that his firm, Earth Tech, will begin the annual hand-dug channel maintenance and IRMA debris removal work. The project is estimated at 40 days utilizing 6-8 workers. UPDATE ON EXOTIC MAINTENANCE None 2 Pelican Bay Services Division Clam Bay Committee Meeting May 3,2018 CANOE TRAIL MARKER 12 Mr. Sterk commented that canoe trail marker 12 remains on the County's list of markers to be replaced. UPGRADE MODEMS ON TIDAL GAUGES (ADD-ON) Ms. Jacob commented that she will work with Mr. Sterk and/or Mr. Kevin Locher(Locher Environmental) to upgrade the modems on the tidal gauges, at a maximum estimated cost of $2,000. The deadline to upgrade is December 2019. CLAM PASS UPDATE ON DREDGING Mr. Dorrill provided an update on the current dredging project,which may be substantially complete by Tuesday,May 8. He commented very positively on the quality and speed of the work of the contractor, Cavache, Inc. H&M APRIL TIDAL RATIO RESULTS Ms. O'Brien commented that the April tidal ratios look good. Mr. Dorrill commented that Dr. Dabees reported to him that this morning's tidal ratios were .76 or .78 which were the highest he has ever seen. FDEP REQUIRING IDLE SPEED SIGNAGE Ms.O'Brien commented 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. Mr. Dorrill commented that he will discuss this issue with Dr. Dabees. WATER QUALITY PROPOSAL FOR COPPER SEDIMENT TESTING IN UPPER CLAM BAY Ms. O'Brien commented on the Turrell,Hall&Assoc. sediment testing proposal of$2,962 to help determine the source of high copper at Station#9 (as provided in the agenda packet). Mr. Hirniak motioned, Ms. O'Brien seconded to approve the Turrell, Hall & Assoc. sediment testing proposal of$2,962. The motion carried unanimously. COPPER RESULTS Ms. O'Brien commented that November 2017—January 2018 copper results look good. UPLAND POND WQ REPORTS Ms. O'Brien commented that on 4/16/18 the Water Management Committee suggested that the Clam Bay Committee take another look at the possibility of reducing the proposed expenditure of$25,000 for four CH2MHi11 quarterly water quality reports on WQ data from 28 of the upland ponds we manage. Mr. Shepherd questioned what is actionable as a consequence of gathering this data. Ms. O'Brien commented that we are currently impaired for copper and not meeting the criteria for total phosphorus in Clam Bay. She suggested that the FDEP may ask, "What are your inputs from the upland ponds into Clam Bay?" Ms. O'Brien commented that the water quality data is collected for documentation purposes and to provide to the FDEP as a defense and/or response to an inquiry. Mr. Hirniak commented that this documentation would show that we are 3 Pelican Bay Services Division Clam Bay Committee Meeting May 3, 2018 "proactive" and continue to monitor the data closely. Ms. Kitchener commented that the action of "trying"keeps the FDEP at bay. Ms. O'Brien suggested that Mr. Hall and Dr. Tomasko weigh in on whether we should continue the quarterly reports "as is,"or could we change the scope and/or frequency. Mr. Trent Waterhouse commented that the PBSD is the managing entity of Clam Bay, and the PBF has jurisdictional oversight, as acknowledged by the FDEP. Mr. Dorrill commented that a violation by FDEP could result in the FDEP setting TDML (total daily maximum load)parameters or they may set mitigation requirements. DATA NEEDED FOR TOMASKO WO REPORT Ms. O'Brien suggested that THA be given only the monthly water quality data for the six berm sites, without including any extraneous data. CONTRACT FOR THA WO WORK FOR 2018 Ms. Kitchener commented that the THA water quality contract expired on April 11. Mr. Dorrill will work with Ms. Jacob to get a new contract in place. NEXT MEETING: By consensus,the committee agreed that the next meeting of the committee would be held on July 12 at 1:30 p.m. ADJOURNMENT The meeting was adjourned at 2:50 p.m. Susan O'Brien, Chairman Minutes approved [ 1 as presented OR [ ] as amended ON [ ] date 4 Humiston& Moore Engineers 1 ClamPass-TIDE Agenda item#6a Page 1 of 3 CLam Pass Tide Monitoring - Click bgisfor Maintenance Dredging Pt oiect details ide Gages Location'. ( ,»4 ` •17' . ;:s..,,s.A f ,,,-,--/,:,,, .h.A.d; Monthly Time Series 2018(Click on Thumbnails to Expand) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Mean Low TideTime Lag -2018 300.0 PASS DOTINGI _ 250.0 1200.0 ^ ■Marker 4 3 150.0 ■tgrleer 14 • • ■ arWr26 1 100.0 -I ■Marker 32 •Mtge net 50^0 -' working 0.0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Gage/Gulf Mean Tide Ratios-2018 0.90 PASS 0_go ^ DREDGING_ 0.70 •d+s"rot working f0.60 ,, ...... ■Marker 4 y 0 5 ■Marker 14 0.40 ' ■Marker 26 m 1 0.30 ■Marker 32 Elibili over fiabkty ..,.. NaVelot Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 44 14. Gage/Gulf Mean Tide Ratios-2017 0.9 V= H..*kery'CA a 0-41 - Tropical Storm Early 0.6 Marker 4 OS Marker 14 Marker ■Marker 26 03 aMarker 32 p;2 comae 0.1 Patorro PAPP frN r es Jan Feb Mar Apr Map km Jul Aug Sep Oct Nov Dec 48114^ https://www.humistonandmoore.com/clampass-tide 7/2/2018 Humiston&Moore Engineers I ClamPass-TIDE Agenda item#6a Page 2 of 3 Gage/Gulf Mean Tide Ratios -2016 0.9 PASS T.S. 0.8 - DREDGING T.S.COUN HERMI NE :E:rE : 03 i L,Marker 32 02 crm 0 __.__ +. ..... _�_.. .,.. r. .-.. y Markers Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec a&Ja. 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 Laq: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. https://www.humistonandmoore.com/clampass-tide 7/2/2018 RI M #O E M I I Ifq I I IR I IR I II I ' c _.... .:..r ......:.'.:...+. -N -...:. .....(..R .yam.LT! • N - _....... ..r..N ...i N ....� ....i ...N �m _ . ..._07 —O • -13. r — r r r 00 ....co .,-GO.- --..... .......:- 034- N r r r r C ,4 -E.:- .....- . a O at co as € " a „r —..... r r ...._O —... O —.... O ........Q r.+ _O ..r......' O ..r....' O� O -..... O -+ -O cp • • T O T OJ Oa -O -` -O .i.....;.. gy -4..... ... gV .} _ ......,.., .��gy }...... ,.. gyy - . gy I II I l I I I I O I I I N 0 N. O N 0 C.t O N 0 CC':9O N O N N 0 f'. O Agenda item#6c Page 1 of 2 David Cook 6' Fwd-FW:Clam Pass-Construction Drawings and Specifications for PBSD review March 26,2018 at 3:25 PM Neil Dorrif . Scott William Streckenbein , Jim Hoppensteadt Susan O'Brien Neil,in reading through this document I was struck by the language covering manatees-section 10.8 and especially 10.8.2 It says that Florida DEP requires that there be an idle speed and no wake restriction in the Clam Bay ecosystem as a condition of the permiiI I know this would beyour personal opinion and not a legal one,but does this mean that we already have standing under Florida law to post idle speed in Clam Bay? The permit is a multi-year permit,under which this dredging is taking place. Is that correct? What do you think'? ` Is there other language in the original permit that supports these same comments? anks Dave Forwarded message------ From:JacobLisa< Date:Mon,Mar 26,2018 at 2:13 PM Subject:FW:Clam Pass-Construction Drawings and Specifications for PBSD review To:David Cook( )< Dave,here's the Clam Pass draft construction plans and the technical specs. Let me know if you need anything else. Thanks, Lisa From:Matthew Fleming[ Sent:Thursday,March 22.2018 3:42 PM To:JacobLisa< >:Mohamed Dabees< Cc:Celia Fellows< Subject:Clam Pass-Construction Drawings and Specifications for PBSD review Lisa. As we discussed this morning-attached are the latest and greatest of the Clam Pass drawings and specs for PBSD to review prior to Monday's meeting. Matthew Matthew Fleming, M. Sc. Humiston &Moore Engineers office: 239-566-0649 x105 cell: 239-572-4903 Agenda item#6c Agenda VtgirAli 2 2018 Clam Pass Maintenance-Technical Specification DRAFT should also be contacted in Jacksonville (1-904-232-2580) for north Florida or in Vero Beach(1-407-562-3909)for south Florida". 10.8.1.4.Siltation Barriers, if used, shall be made of material in which manatees cannot become entangled, are properly secured, and are regularly monitored to avoid manatee entrapment. Barriers must not block manatee entry to or exit trom essential habitat. 10.8.1.5.If manatees are seen within 100 yards of the active daily construction/dredging operation, CONTRACTOR shall ensure that all appropriate precautions shall be implemented to ensure protection of the manatee. These precautions shall include the operation of all moving equipment no closer than 50 feet of a manatee.CONTRACTOR is advised that operation of any equipment closer than 50 feet to a manatee shall necessitate immediate shutdown of that equipment. 10.8.1.6.CONTRACTOR shall report any collision with and/or injury to a manatee immediately to the Florida Marine Patrol (1-800-DIAL-FMP, or 1-800-342- 5367) and to the Florida Fish and Wildlife Commission Bureau of Protected Species Management at(850)922-4330. 10.8.2.The Clam Bay ecosystem contains waterways that are difficult to navigate due to shallow water depths and meandering channels lined with protruding mangrove branches and roots to protect the significant natural resources and water quality of the Clam Bay ecosystem,and to provide protection to the public safety,a condition of the DEP permit requires that there be an idle speed and no wake restriction on motorized vessels used in the system.The CONTRACTOR shall • adhere to an idle speed and"no wake"requirement in the project area. 10.9. Marine Turtle and Shorebird Nesting Protection 10.9.1.The project construction will occur during the shorebird nesting season and potentially a small portion of the sea turtle nesting season. Daily clearance is necessary for work activities continuing during the day. Nighttime activities are regulated in the state and federal permits. All requirements of the state and federal permits relating to endangered sea turtle and shorebird protection and work within the season must comply with those conditions. Daily clearance from the sea turtle and shorebird monitors, as deemed necessary, shall be required prior to the start or continuation of construction activity and movement of equipment across the beach. When moving heavy equipment from Construction Access to the area of WORK, a spotter shall walk ahead of the equipment to ensure safety to endangered species and pedestrians. 10.9.1.1.A pre-work conference shall be held between representatives of the CONTRACTOR, the ENGINEER, the Marine Turtle Permit holder, shorebird monitor, and a representative of the State Department of Environmental Protection, the U.S. Army Corps of Engineers, and Florida Fish and Wildlife Conservation Commission(FWC)prior to commencement of WORK. 10.9.1.2.In the event that an unmarked marine turtle nest or a dead,injured, or sick marine turtle is discovered during construction activities, the marine turtle permit holder and the Bureau of Protected Species Management shall TS-12 Agenda item#7c Page 1 of 1 Clam Bay Copper ug/L Collection Date CB1 CB2 CB3 CB4 CBS 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 Agenda item#7g Page 1 of 1 Background information on CH2MHill reports on Water Quality in PB's upland ponds • Clam Bay is a Class 2 water body so it is subject to regulation by Florida Department of Environmental Protection (FDEP). • Between 2005 and 2012 FDEP collected and analyzed 25 water samples in Clam Bay and found that 12 of the samples (48%) exceeded allowable limits for copper. • In November 2011 PBSD began collecting and analyzing water samples on a quarterly basis from selected ponds in PB because stormwater from these ponds flows into Clam Bay, and CH2MHill began doing quarterly reports on the results, costing about $25,000 annually. • In 2012 FDEP identified Clam Bay as impaired for copper and said detailed documentation of efforts to remedy the issue, e.g. monitoring water quality in upland ponds, was needed. • In 2012 the Environmental Protection Agency adopted nutrient concentration criteria for Clam Bay(Florida Administrative Code (FAC) 62-302.531). This FAC established criteria for total phosphorus and total nitrogen in Clam Bay. • In September 2013 the PBSD Board approved the immediate cessation of copper sulfate to treat algae in ponds PBSD manages and asked all PB associations to also cease using copper sulfate. • The 2017 Clam Bay WQ report found 16 of 98 samples exceeded allowable limits, making Clam Bay impaired for copper. (Reducing the number of samples from 48% in 2005-2012 to 16% in 2017 is significant progress, but Clam Bay is still impaired for copper.) • The 2017 Clam Bay WQ report found that 33 of 98 water samples (34%) in Clam Bay exceeded allowable upper limits for Total Phosphorus, significantly more than the allowable 15%. • In 2017 the contract for CH2MHiIl's reports expired. Water samples from 29 selected ponds are still being collected and analyzed quarterly, but no reports are being done. • Thus Clam Bay is currently impaired for copper and total phosphorus and a major part of the documentation that PBSD was doing to demonstrate its efforts to address the issue is no longer being done. • The Clam Bay Committee will address this issue at its meeting on July 12, 2018. Prepared by Susan O'Brien July 2, 2018 Aaanrla item#7g 4350 West Cypress Street Page 1 frtMesassoc.com Suite 950 Tampa,FL 33607 813.207.7200 phone 813.207.7201 fax memorandum date March 7, 2018 to Tim Hall,Turrell, Hall and Associates,Inc. from David Tomasko, Ph.D. Emily Keenan,M.S. subject Annual Report on Clam Bay Numeric Nutrient Concentration(NNC) Criteria Executive Summary Water quality data collected from Clam Bay between November 2016 and October 2017 were analyzed to determine the degree to which the waters of Upper, Inner and Outer Clam Bay are in compliance with relevant criteria. For nutrients, it was found that levels of phosphorous were out of compliance with existing site-specific criteria for Clam Bay. Levels of nitrogen were not out of compliance. Based on data from throughout the Clam Bay system, there is a positive correlation between phosphorous concentrations and the amount of algae in the water column, and an inverse correlation between phosphorous and levels of dissolved oxygen (DO). These results suggest that phosphorous concentrations are at potentially problematic levels in Clam Bay, and they should be carefully monitored, to ensure that conditions do not deteriorate. Should phosphorous continue to exceed established criteria; the County would benefit from the development of a detailed and data-rich phosphorus loading model, to develop appropriate management responses. Although this is supposition at this time, the temporal pattern of phosphorus exceedances suggests that nesting behavior of wading bird might better explain the temporal pattern of phosphorus enrichment than stormwater runoff. This potential link needs to be investigated in greater detail. Levels of DO are problematic when compared to newly adopted criteria developed by the Florida Department of Environmental Protection (FDEP). For DO, 13 of the 98 samples had levels lower than existing guidance criteria from FDEP, a value in excess of the 10 percentile exceedance rate allowed by FDEP. For copper, 16 of 98 samples collected in Upper, Inner and Outer Clam Bay exceeded FDEP criteria for Class II marine waters. Based on this exceedance rate, the waters of Clam Bay would be determined to be "impaired" for copper. The majority of the copper impairments occurred within Upper and Inner Clam Bay, at stations 1, 2 and 3, and special attention should be placed on determining the potential cause(s) of elevated copper at those locations. The determination of copper exceedances in freshwater sampling sites in the watershed requires the simultaneous collection of data on "hardness". Unfortunately, not all of the copper values from freshwater locations were accompanied by hardness values, so the degree of impairment cannot be fully investigated. Future sampling should include measurements of water clarity for all Clam Bay sites, and measurements of hardness for all freshwater sampling sites. Agenda item#7g Page 2 of 14 Background Over the past several decades, it has become well-established that an over-abundance of the plant nutrients nitrogen and/or phosphorous can have adverse impacts on the water quality and ecology of lakes, rivers and estuaries. Excessive nutrient supply can stimulate the growth of nuisance plants, creating nuisance algal blooms. In a system like Clam Bay, algal blooms can reduce water clarity, which is essential for the continued persistence of seagrass meadows, which provide food and shelter for the majority of recreationally and commercially important species of fish and invertebrates (such as crabs and shrimp). Once algal blooms die-off, their decomposition can reduce levels of DO, which is essential to most forms of aquatic life. Successful management of coastal waterbodies thus requires the collection, analysis and interpretation of results from water quality monitoring programs, particularly data related to nutrient amounts and sources. Determination of Impairment Status In 2012, the United States Environmental Protection Agency formally adopted nutrient concentration criteria for Clam Bay, as produced for Collier County, which had also been reviewed and approved by FDEP. The Numeric Nutrient Concentration (NNC) criteria produced for Clam Bay are termed Site Specific Alternative Criteria (SSAC) and they are listed in Florida Administrative Code (FAC) 62- 302.531. The SSAC for Clam Bay was derived based upon a relationship between salinity and nutrients that was initially established at one of FDEP's "reference sites" in Estero Bay. The need to take into account salinity was based upon the finding that nutrient concentrations in estuaries and tidal rivers vary as a function of rainfall and runoff, as well as the amount of tidal influence. For example, even in FDEP's reference sites, which were chosen to represent waterbodies with little to no human impacts, nutrient concentrations are lowest on high tides, in areas close to passes, and during dry periods with little rainfall-generated stormwater runoff. Even in these reference sites, nutrient concentrations increase as one moves farther away from passes, as the tide falls, and during wet seasons and wet years. Therefore, a single nutrient concentration criterion does not make much sense, if water quality data from even pristine locations could potentially pass or fail proposed criteria simply as a function of location, tidal stage or antecedent rainfall. The SSAC for Clam Bay therefore considers the concentration of nutrients, while also taking into account the salinity, such that a finding of elevated nutrients in combination with higher salinities is considered more problematic than elevated nutrients in combination with lower salinities. As such, the relationship between nutrients and salinity is determined as part of the process to determine if the waters of Clam Bay are "impaired" or not. Also, the frequency with which values exceed NNC criteria is taken into account when determining the appropriate management response, as is the amount of time over which an exceedance has occurred. For example, if nutrient concentrations were to exceed NNC criteria by a relatively small percentage, and if such an exceedance was to only last a short period of time, the appropriate management response would be different than if water quality was to exceed criteria to a larger extent, and if the condition of exceedance was to have lasted for a greater period of time. Therefore, the management response associated with any impairment determination is proportional, and based upon both the magnitude and duration of any exceedances. Based on prior work conducted in Clam Bay, it was found that the amount of floating microscopic algae (i.e., phytoplankton) in the bay was likely stimulated by both Total Nitrogen (TN) and Total Phosphorous (TP). Consequently, the amount of both TN and TP in Clam Bay is used to determine the degree of nutrient enrichment of Clam Bay's waters. As outlined in FAC 62-302.531, the water quality status of waterbodies is to be determined on an annual basis, preferably within a calendar year. For this report, the data collection effort comprised 12 2 Agenda item#7q Page 3 of 14 months of effort, but the 12 months did not fall within a single calendar year. Nonetheless, the compilation of results and the interpretation of results presented in this report should be fully consistent with that which would have occurred if the full 12 months of data had been collected in a single calendar year. As outlined in FAC 62-302.532, for each year, each individual TN and TP value collected within Clam Bay is compared to an "upper boundary" of the expected relationship between those two variables and salinity, which was originally informed by the water quality data from an FDEP-designated reference water body. The formal name of the upper boundary condition is the "90th percentile prediction limit" which was originally derived for the relationship between nutrient concentrations and salinity in Clam Bay, and which is based on the determination by FDEP that Clam Bay's water(in 2012) was sufficient to protect its biological integrity. In other words, a TN or TP concentration higher than the 90th percentile prediction limit is a nutrient concentration higher than at least 90 percent of the values that would be expected, after taking into account the salinity value at the time that the water quality sample was collected. The number of occasions when a nutrient concentration is higher than the 90th percentile prediction limit is quantified for each year, and an annual percent exceedance is then calculated. To be consistent with methods currently used by FDEP, if more than 13 percent of TN or TP concentrations exceed the 90th percentile prediction limit(for a given year) then the year as a whole is classified as one where water quality is out of compliance with the existing criteria. If fewer than 13 percent of the values exceed the 90th percentile prediction limit, then water quality is not considered to be out of compliance. If more than 15 percent of TN or TP values exceed the 90th percentile prediction limit, then the degree of impairment is determined (as per FDEP guidance) to be more problematic than if only 13 percent of values exceeded the established criteria. The screening of water quality data against the adopted NNC criteria is performed as outlined in Figure 1, where different outcomes are given different scores, depending on the frequency of impairment, as well as the duration that the impairment has lasted. Figure 1. Flow chart for determining water quality compliance in Clam. Do?13%of all TN&for fP values from a calendar year r exceed the 90%prediction limit No from the reference W8ID? tautcomeit Yes u ?131a M,ignrtudeof ?..15% exreedarrce v _. Duration of Duration of exceedance exceedance 1 year >1 year 1 year 2 year Outcome'I Outcome2 r7uit°me ) rNu omit The possible outcomes displayed in Figure 1 are then compared for both TN and TP, and the combined outcomes are converted into designations of"green", "yellow" and "red"which correspond to an increasing need for concern (Figure 2). 3 Apanda itam#7p Page 4 of 14 Figure 2. Management response matrix using outcomes for TN and TP. Total Phosphorus Total Nitrogen Outcome 0 Outcome I Outcome 2 Outcome 3 4-iv Outcome 0 19 Outcome 1 Outcome 2 Outcome 3 111111 As a final step, the appropriate management response to water quality within a given year is then identified based on the results from Figure 2. For example, if water quality data suggest that TN and TP concentrations are elevated, then it is important to determine if the ecological health of Clam Bay appears to be adversely impacted by those nutrient concentrations. As a test of the impact of potential nutrient enrichment, water quality data would then be tested to determine if phytoplankton levels are perhaps higher, or dissolved oxygen levels lower, based on nutrient concentrations (Figure 3). Figure 3. Management response actions in response to various outcomes Green Response Ydlow or Red evaluation kFt1€ Evaluate phytoplankton/ significant dissolved oxygen (p<0 OS) Not significant response to nutrient (fa,0.0S) concentrations Evaluate water clarity Not significant response to chlorophyll-a <r),0 05) Significant ti><0.05) Small difference or short duration dent3fs„{ is t.=!coos€ I1 edify potnrtt l arc targedifferenceor 4dU'4,5 and r cc?tlat'=.i+ r rc d C4 R 3t? s' long Chit Aron f 'i,t.ionSfS In this manner, management responses are proportional to the frequency and duration of exceedance conditions, as well as the determination of whether or not nutrient supply appears to be causing adverse water quality conditions. With this information as background, the rest of this report will focus on the analysis of water quality data collected during the period of November 2016 to October 2017, at nine open water locations shown in Figure 4. In addition to the open water sample sites, a number of 4 Agenda item#7g Page 5 of 14 sampling locations were located in the stormwater treatment ponds east of the mangrove fringe on the east side of Outer, Inner and Upper Clam Bays (Figure 4). Figure 4. Locations of monthly monitoring stations sampled for Clam Bay and its directly adjacent watershed. a, , ,� ,.. .. �.- - •, , _ } to _ .a .'e.E, 'k 1 , ' .'1... .,t Int t Y.:... 3,.s.. .,--•'- `` ". is +ye. __ t ♦�,z, ar 4X94 x Via.,,s ----'''::":.: -..77:' Z tY ,'a S" ,i ----1v... ..: T I ,R. ' g �► --gyp.. - - {,,,.a°xs^--;:l...''....S rt ♦a .4 3rt w.. , °„ -r �*4r- e Fi7:+�; s�rgsv ^' �$ vity., ...w;,,,. i irx*3j r x C. Y..4 a ,* _ ce a BAY'SBA T 111N ci4M BdQYI 9 clam CIM ears N a ri � "' awcy Oip, � u17r. } ° ,°x " $t �x ' arS - 1,61.6.444!.;%;;.T.;'rc � SAwi g, , —.x � l,jt gym €, �; y.s HaflraNNIMMM t Le SAM BAYS®al®©0 ®moo®©o© s�Ise.MMl4.,tytwfr CURRENT SAMPLE LOCATIONS �c:,c:ac�®co ©� — Data Analysis—Nutrient Status The analysis conducted below was used to assess the water quality status of Clam Bay during the months of November 2016 to October 2017. While the period of analysis was not from a single calendar year, it does encompass twelve consecutive months of data collection. A monitoring event was not performed in September 2017 due to the landfall of Hurricane Irma in Immokalee, Florida. In addition, a sample was not collected at station Clam Bay 1 in October 2017 due to debris blocking access to the monitoring site. Therefore, a total of 98 water quality samples were reported within Clam Bay for the analysis period. Water quality data from Clam Bay and its watershed were provided by Turrell, Hall and Associates, Inc. For comparison with the FDEP adopted SSAC for Clam Bay, a listed within FAC. 62-302-532, the water quality data set provided by Turrell, Hall and Associates was analyzed based on the following: 5 Agenda item#7Q Page 6 of 14 "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 Upper Limits for TP and TN concentrations noted above are derived based on Equations 1 and 2, respectively: Equation 1: TP Upper Limit (mg/L)= e(-1.o6256-o.0000328465`Conductivity(Ns)) Equation 2: TN Upper Limit (mg/L)= 2.3601 —0.0000268325*Conductivity(pS) The nutrient dataset examined 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. TN and TP concentrations were compared to the derived upper limit thresholds to quantify the presence or absence of elevated concentrations of TP and/or TN, with results listed in (Appendix A). Over the period analyzed (November 2016 to October 2017), a total of three (3) ambient water quality values for TN exceeded the respective TN Upper Limit, for an exceedance frequency of approximately 3 percent. In comparison, 33 of the 98 TP measurements (approximately 34 percent) exceeded their respective TP Upper Limit. Based on these results, the frequency of exceedance would not be high enough for the waters of Clam Bay to be determined to be impaired for TN, but those same waters would be determined to be impaired for TP. Table 1 displays the results in a manner intended to allow for a quick visualization or results by month and by station. Sampling locations and months are color coded as to the results, with green representing "passing" values, boxes with an "x" representing data that numerically exceed established criteria. In addition, boxes in yellow represent values within the error rate (i.e., ±5 percent) of threshold criteria, whether in exceedance, or slightly below exceedance. Table 1. Representation of frequency of impairment for TN and TP for different site and date combinations. Green represents sample clearly not out of compliance with criteria. Boxes with "x" represent values out of compliance with criteria. Boxes in yellow with "x" represent data out of compliance, but within the range of resolution of laboratory values (i.e., ±5 percent) and/or rounding errors. Boxes in yellow but without "x" represent values in compliance, but also within range of resolution of laboratory values (i.e., ± 5 percent) and/or rounding errors. Clear cells represent a lack of data. Month 1 + 2 3 4 5 6 -- 7 — 8 g _ TN TP TN TP TN TP TN TP TN TP TN TP TN TP TN TP TN TP Nov-16 x — Dec-16 x Jan-17 Feb-17 x x x x Mar-17 x x x x x Apr-17 x x x x x May-17 x x x x x x x x x Jun-17 x x x Jul-17 Aug-17Sep-17 , Oct-17 x x x x x x x x Acanrla item#7g Page 7of14 The overall pattern shown in Table 1 is that of reduced frequencies of exceedance of criteria for TN, compared to TP. As well, the months of November 2016 to January 2017 and then July to August 2017 had relatively low rates of exceedance. The months of February to May had, on average, the highest rates of exceedance of nutrient criteria, usually for phosphorus. These results suggest that nutrient impairment may not be driven by stormwater runoff alone, as the months of February to May are typically some of the drier months in Southwest Florida. In contrast, the months of July and August of 2017 exhibited lower rates of exceedance, even though they typically represent times of maximal runoff of stormwater from the Clam Bay watershed. A possibility, worthy of further investigation, is whether or not the trend of elevated phosphorus concentrations might reflect seasonal changes in the abundance of wading birds, and in particular the nesting habits of wading birds. In a study titled "South Florida Wading Bird Report" it was noted that wood storks (Mycteria americana) typically initiate nesting in South Florida in the months of February to March (Cook 2016). Other species, such as White Ibis (Eudocimus albus) and herons within the genus Egretta nest somewhat later, up to April, but they extend their nesting behavior until May or June, if the wet season starts later in the year(Cook 2016). Thus, the abundance of wading birds, particularly nesting pairs and their offspring, may have an influence on water quality not only in Clam Bay, but in the nearby ponds that drain into Clam Bay. Bird guano has an exceptionally high phosphorus content, which could explain the apparent concurrence between those months with the greatest frequency of impairment for phosphorus (February to June) and those months where wading bird nesting in South Florida is at a seasonal high (February to May). Since the TP exceedances have occurred in two consecutive reporting periods, the outcome from the flowchart shown in Figure 1 would that of a score of"3"for TP, compared to a score of"0"for TN (Figure 2). With two years' worth of data, the combination of outcome "3"for TP and outcome "0" for TN would result in a "yellow" management response, as illustrated in Figure 3. Since the TP exceedance rate was greater than 15 percent, then the "yellow" management response would be the outcome for this first year's data collection effort. Consequently, the following additional data investigations were conducted: • Determining the relationship, if any, between TP and chlorophyll-a • Determining the relationship, if any, between TP and dissolved oxygen • Determining the relationship, if any, between chlorophyll-a and water clarity Depending upon the findings of the analyses listed above, management implications would be developed, which could include the need to determine the basis for a potential adverse impact on water quality. A review of the last 12 months of data indicated a direct relationship between TP and chlorophyll- concentrations (Figure 5) as well as an inverse relationship between TP and DO (Figure 6). As measurements of water clarity were not available for review, water clarity data was not included in the reviewed data sheets. Unfortunately, this did not allow for the determination of whether or not there was a correlation between chlorophyll-a concentrations and water clarity. As such, we were unable to evaluate the influence of chlorophyll-a on water clarity in Clam Bay. 7 Afl nria itam#7d Page 8 of 14 Figure 5. Relationship between total phosphorus and chlorophyll-a over the period of November 2016 to October 2017 in Clam Bay (p<0.0001). 0 $01 10 801 ° 40- 0 0 0 0 O 0 ° ° 20-4 .�,...+^'.. O 0 m p oo o ° ° 0 0 O O ° p O O Ob B 0- 0.05 0.10 0.15 020 0.25 Total Phosphorus(mg/i..) Figure 6. Relationship between total phosphorus and dissolved oxygen over the period of November 2015 to October 2016 in Clam Bay (p<0.001). 0 0 °p 0 0 0 000 0 0 OO 0 0 00 8 ° °O °O,p°° O 00 ° 00 3 o 0 0°0-.0. 0 0 O •p 0 00 O ° 0 0 O l9 ° K � 0 0 0 000 0 0 0 G O 0 0 O ° 0 O ° O 0 2- o ° 0 0 0 0- 0 -- 0 05 0.10 0.15 0.20 025 Total Phosphorus(mg In addition to the data assessments described above, data from Clam Bay outfall monitoring stations were compared to the proposed Downstream Protective Values (DPV) derived 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 found at those locations (Appendix B). The median DPV quantity represents a value that would be expected to be exceeded approximately 50 percent of the time, while the 90th percentile value represents a concentration sufficiently high that only 10 percent of values would be expected to be higher. Using this approach, the amount of TN or TP in the water 8 A9anria itam#7g Page 9 of 14 column at stations sampled in the Clam Bay watershed can be compared to criteria that are meant to be protective of the open waters of Clam Bay. The TN and TP concentrations in DPV estimates are expected to be higher than concentrations in the open waters of Clam Bay, as the influence of the more saline and lower nutrient content waters of the Gulf of Mexico would not yet have diluted the higher nutrient concentrations found in freshwater inflows from the watershed. The median and 90th percentile DPVs for TN are 1.31 and 1.8 mg/L, respectively. The median and 90th percentile DPVs for TP are 0.10 and .25 mg/L, respectively. For data collected at the outfall monitoring sites, 53 and 17 percent of the TN concentrations exceeded the median and 90th percentile DPV values for TN, respectively (Table 2). For those same outfall monitoring sties, 83 and 32 percent of the TP concentrations exceeded the median and 90th percentile DPV values, respectively (Table 1). Table 2. Percentage of TN or TP concentrations from outfall stations which exceeded the median or 90th percentile DPV values. Total Nitrogen Total Phosphorus DPV Median 90th Percentile Median , 90th Percentile Below 47 83 17 68 Exceed 53 17 83 32 Results— Nutrient Status Based on the data collected from this year's monitoring efforts, the waters of Clam Bay do not appear to be problematic in terms of nitrogen, but they do exceed regulatory criteria for phosphorous. The abundance of phosphorous positively correlates with chlorophyll-a concentrations in Clam Bay, which suggests that the availability of phosphorous influences the amount of phytoplankton in Clam Bay. Also, increased phosphorous concentrations are inversely correlated with levels of dissolved oxygen in Clam Bay. Data collected from the outfall monitoring stations suggest that nitrogen concentrations are somewhat elevated, but that most of the elevated concentrations of nitrogen are from the highest values recorded, rather than there being a "typical" condition of elevated nitrogen enrichment. For phosphorous, elevated concentrations are found both in typical conditions and also amongst the highest concentrations, compared to guidance criteria. These results strongly support the recommendation that the watershed and open waters of Clam Bay should continue to be monitored on a regular basis, as there is the possibility that phosphorous loads, in particular, could become problematic to the water quality and ecosystem health of Clam Bay, particularly if phosphorous concentrations were to increase over time. Additionally, as nutrient concentrations vary as a function of the balance between stormwater runoff and mixing with the waters of the Gulf of Mexico, the tidal prism for the Clam Bay system should be maintained such that it continues to allow for sufficient tidal exchange of the waters of Upper, Inner and Outer Clam Bay. Results— Dissolved Oxygen For levels of DO the applicable regulatory criterion, as outlined in FAC 62-302.533, is that minimum DO levels (for Class II waters like Clam Bay) shall not be lower than 42 percent saturation more than 10 9 AgPnria itam#7g Page 10 of 14 percent of the time (for average daily values) or that 7-day average values shall not be below 51 percent saturation more than once in any 12-week period, or that the 30-day average DO percent saturation shall not be below 56 percent more than once per year. The less-restrictive 7-day and 30-day criteria require DO measurements to be made over a 24 hour period, which is not applicable for comparison with water quality data collected at a single time of day, once a month. As such, the more restrictive criterion was used for Clam Bay, and DO values (in units of percent saturation) were compared against the 42 percent saturation value. Results are shown in Figure 7. Figure 7. Dissolved oxygen values (percent of 100 percent saturation) for nine stations in Clam Bay, over the period of November 2016 to October 2017. 0 O 8 too 0 8 8 ° 0 @ 0 ° 0 °o 0 8 so 8 0 8 0 0 0 o ° o ® ° ° ° 0 a ° 0 0 0 0 0 'rf 60 ° 8 0 ® N ° ° 0 0 0 0 0 0 0 ° ° O O O 40 Class If Standard G ° 0 0 0 20 0 0 0 0 T Nov Daa Jon Feb Mar Ad' Mar Jtn Jo Auc Sp Oct tiov 2016 201', Sampling Date Since DO values were collected at nine stations for eleven months (n = 98) it would take 10 values below 42 percent saturation for Clam Bay to be considered to be out of compliance with the DO criteria listed in FAC 62-302.533. Thirteen values show DO at lower than 42 percent saturation, the majority of which occurred during the months of July to October. Based on these results, the waters of Clam Bay would be considered to be out of compliance with existing DO criteria. Of the thirteen depressed values, five were reported at the Clam Bay 2 monitoring location, which is located in a narrow channel between Upper Clam Bay and Inner Clam Bay (Table 3). 10 Agenda itam#7g Page 11 of 14 Table 3. Dissolved Oxygen Saturation values at sites Clam Bay 1 to 9, in units of%. Values highlighted in yellow are below the criteria for Class II waters (42%). Station 1 2 3 4 5 6 7 8 9 11/9/2016 65.9 69.1 92.5 84.0 94.1 93.5 79.0 84.7 77.9 12/6/2016 65.8 48.5 73.2 86.6 103.6 95.1 93.5 94.1 76.5 1/19/2017 61.9 33.3 72.4 102.5 98.4 97.4 101.6 79.5 71.9 2/23/2017 49.6 56.7 72.4 93.8 105.8 89.9 105.9 92.8 83.7 3/21/2017 59.6 60.9 102.1 91.1 100.1 99.6 80.2 81.3 72.4 4/18/2017 54.3 17.2 98.6 88.4 99.5 87.7 85.1 83.2 71.3 5/24/2017 69.9 57.1 80.1 85.8 103.0 86.0 69.6 7.6 59.3 6/21/2017 44.2 50.5 60.6 80.3 92.6 89.8 70.7 60.0 52.7 7/13/2017 47.9 20.5 42.7 41.0 56.0 46.0 63.1 21.1 41.1 8/14/2017 28.9 19.3 36.5 48.2 84.7 80.9 83.6 61.2 65.2 10/4/2017 - 0.4 29.3 33.0 76.6 69.5 59.9 53.1 50.2 Results - Copper For levels of copper, there are different criteria used for marine waters vs. freshwater systems such as stormwater ponds. For marine waters, the standard, as listed in FAC 62-302.530, is that concentrations are not to exceed 3.7 pg / liter. However, the State of Florida's Impaired Waters Rule (FAC 62-303) allows for a certain amount of"exceedances"to occur, before water quality is considered to be out of compliance. Table 4 summarizes the data collected from all stations, from November of 2016 to October of 2017, for Stations Clam Bay 1 to Clam Bay 9, all of which are located in the open waters of Upper, Inner or Outer Clam Bay. 11 Agenda item#7g Page 12 of 14 Table 4. Copper values at sites Clam Bay 1 to 9, in units of pg / liter. Values highlighted in yellow exceed copper criteria for Class II waters (3.7 pg Cu / liter). Station 1 2 3 4 5 6 7 8 9 11/9/2016 2.34 3.39 2.30 2.25 1.63 1.50 1.18 2.03 1.30 12/6/2016 2.33 2.93 5.10 2.45 2.39 1.78 1.27 1.88 1.72 1/19/2017 2.57 3.56 2.11 1.99 0.82 0.80 0.96 1.11 2.02 2/23/2017 2.51 3.35 1.60 1.12 0.85 0.85 1.50 2.57 2.60 3/21/2017 7.97 4.08 1.71 1.12 0.89 0.85 1.08 1.09 0.96 4/18/2017 6.48 8.16 1.62 1.24 0.80 0.96 1.28 1.01 1.10 5/24/2017 2.84 4.06 4.99 0.80 0.80 0.96 0.80 0.92 0.95 6/21/2017 3.84 4.24 3.85 0.91 1.20 1.14 1.26 1.11 0.76 7/13/2017 4.70 2.95 3.80 4.08 2.50 2.44 2.37 2.38 2.21 8/14/2017 4.29 3.81 3.22 2.65 1.40 1.22 1.47 1.02 0.70 10/4/2017 2.68 1.27 0.60 0.80 12.60 1.61 0.60 0.60 mean 3.99 3.93 2.87 1.75 1.28 2.28 1.34 1.43 1.36 median 3.34 3.56 2.3 1.24 0.894 1.14 1.27 1.11 1.1 N 10 11 11 11 11 11 11 11 11 #> 3.7 5 5 4 1 0 1 0 0 0 % > 3.7 50% 45% 36% 9% 0% 9% 0% 0% 0% Of the 98 samples collected for copper, 16 of them exceeded the established criteria of 3.7 pg / liter. Based on guidance in Table 3 of FAC 62-303, if a water body has between 97 and 104 samples collected, it would be determined to be out of compliance if 15 values exceeded established criteria. For Clam Bay, 16 of 98 samples collected in Upper, Inner and Outer Clam Bay exceeded FDEP's criterion for copper, which is sufficient for Clam Bay to be determined to be out of compliance for copper. Elevated copper concentrations were observed more frequently stations 1, 2 and 3, which are located in Upper Clam Bay down to Inner Clam Bay, and where the immediate shoreline is that of a natural mangrove fringe. It would be helpful to determine the reason(s) for elevated copper at these stations, as they are responsible for more than 90 percent of the exceedances of copper criteria in the entire Clam Bay system. The determination of copper exceedances in freshwater sampling sites in the watershed requires the simultaneous collection of data on "hardness". Unfortunately, most of the copper values from freshwater locations do not appear to have been accompanied by hardness values, so the degree of impairment cannot be fully investigated. However, 35 of the 61 samples from freshwater locations included results on hardness, and those data are analyzed below. The water quality standard for copper differs between predominately marine waters and freshwater. As classified by FDEP, open waters of Clam Bay have a water quality standard for copper of< 3.7 pg / 12 Adanria item#70 Page 13 of 14 liter. In contrast, the copper standard for freshwater is more complicated, as it requires the concurrent recording of a value for"hardness" in units of mg CaCO3/ liter. The toxicity of copper is mostly restricted to the abundance of the copper ion, and the greater the abundance of other dissolved compounds, the lower the probability that free copper ions will be available to bind with cell membranes, etc. and cause direct and indirect biological impacts. Briefly stated, the higher the hardness level of a water sample, the lower the probability that a given level of copper will be toxic. Once the level of hardness is determined, the copper criterion for a sample collected from freshwater is derived as: Copper standard (mg / liter) = e(0.8545[InH]-1.702) Where: e = the base of the natural logarithm (ca. 2.718281), and InH = natural log of hardness (in units of mg CaCO3/ liter) Thus, the determination of whether a sample meets or exceeds the water quality standards for copper only requires determination of the concentration of copper for marine samples; a concurrent value for hardness is required to determine compliance with freshwater criteria In the data set examined it appears that there were only 35 date and location combinations for freshwater stations where both hardness and copper levels were analyzed. Those stations and date combinations include the following: • The site "Glenview" on the dates of 2/28/2017, 5/22/2017, 6/22/2017, 7/12/2017, 8/15/2017 and 10/3/2017 • The site "PB-11" on the dates of 2/28/2017, 5/22/2017, 6/22/2017, 7/12/2017, 8/15/2017 and 10/3/2017 • The site "PB-13" on the dates of 6/22/2017, 7/12/2017, 8/15/2017 and 10/3/2017 • The site "N-Boardwalk" on the dates of 2/28/2017, 5/22/2017, 6/22/2017, 7/12/2017, 8/15/2017 and 10/3/2017 • The site "N-Berm" on the dates of 2/28/2017, 5/22/2017, 6/22/2017, 7/12/2017, 8/15/2017 and 10/3/2017 • The site "St. Lucie" on the dates of 5/22/2017, 6/22/2017, 7/12/2017, 8/15/2017 and 10/3/2017 • The site "N-41 PIPE" on the dates of 6/22/2017 and 7/12/2017 Copper concentrations at the sites Glenview, N-Berm, N-Boardwalk and St. Lucia exceeded the hardness-normalized copper criteria for Class III freshwater systems during at least one monitoring period. Typically, levels of copper were many times higher than impairment thresholds. These stations are located within the series of open water features on the west side of the Pelican Bay development, just east of the mangrove fringe that separates Clam Bay from its developed watershed. In contrast, none of the copper values from sites N-41, PIPI, PB-11, or PB-13 exceeded criteria for Class III freshwaters. Recommendations For the waters of Upper, Inner and Outer Clam Bay, water quality monitoring should continue at the same nine stations locations sampled in the reviewed data set. For determining compliance with nutrient criteria, chlorophyll-a should continue to be collected (and be corrected for phaeophytin) along with both Total Nitrogen and Total Phosphorous. To ensure results can be compared to NNC criteria 13 AgPnria item#7� Page 14 of 14 established specifically for Clam Bay, values of specific conductance also need to be collected, as they were here. Future sampling should include measurements of water clarity for Clam Bay sites 1 through 9, through the use of a Secchi disk or through the direct measurement of light attenuation coefficients. If phosphorous concentrations continue to be elevated, a more detailed pollutant loading model should be developed, so that loading sources could be identified and appropriate management responses developed. This loading model should include the potential for wading bird populations to be a significant factor, since the overall temporal pattern appears to be that phosphorus concentrations correlate better with presumed populations of wading birds than with stormwater runoff. For copper, the sampling sites in Upper and Inner Clam Bay should be investigated in greater detail, as that these three stations (of 9 total stations) are responsible for more than 90 percent of copper impairments in the Clam Bay system. As well, measurements of copper in freshwater ponds need to have concurrent measurements of hardness, as impairment determination in freshwater samples requires the "normalization" of copper values to the level of hardness in the water. Based on the locations where copper and hardness values were both recorded, it appears that levels of copper are elevated (often to a considerable degree) in the open water features to the east of the mangrove fringe that separates the developed watershed of Clam Bay from the marine waters of Clam Bay. The source(s) of the copper in these ponds should be determined, as those sources could also be impacting the waters of Clam Bay itself, particularly in the wet season. 14 TECHNICAL MEMORANDUM 01112441 Pelican Bay Stormwater Lakes Water Quality Monitoring Program: August 2017 Sampling Event Data Review PREPARED FOR: Pelican Bay Services Division PREPARED BY: CH2M HILL 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: • Nitrate- Nitrite • Ammonia • Total Kjeldahl Nitrogen(TKN) • Ortho Phosphate • 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. Because water quality concerns regarding the potential influence of stormwater discharges these lakes to Clam Bay revolve most{y around nitrogen, phosphorus,and copper,evaluations presentedfrom herein are focused on these parameters. FIGURE 1 Locations of Pelican Bay Stormwater Lake Basins and Monitoring Stations in Relation to Clam Bay Pelican Bay Stormw✓ater lakes Water Quality Monitoring Program:August 2017 Data Review - Y" � std{ ` t.27 t„1.. .,,,J.„tk.,,,t,.. .. ,,.;.-.1 ik:11,v„t't i,t.rt;,. *`:-"ts'44' ' .in*,--,,T..,1°.111..."1.e - i. ;jib '''.\ .444.:''tilt:"7.1::::'04:°19jS.Ift.,iljg .,.. -, j7 *:-°'''''' A..:-.' 0. .'3/4, ,1' z 'i1V- + 4 —:%"4';'; "�r2 '.4';4444rfi4 ' "'• --r.°z xrt. 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'#''Y�< ;211.-,„,,,,_ ,,,, ,,c , ;it, P . ,1 �I 'f,' }� Co t „ F-`?y ; f.7pt55LCS`Ttf45 FW11 anQ AS I-Ii fh1[�Ci� PELICAN BAY STORMWATER LAKES WATER DUALITY MONITORING PROGRAM.AUGUST 2017 SAMPLING EVENT DATA REVIEW TABLE 1 Water Sampling Locations of 29 Stormwater Lakes and Reclaimed Water Source Pelican Bay Storm water 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 MJD 4 5 4-2 Bay 2 6 1-4 Crayton 2 4-4 Bay 4 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 5 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 Interlochen 6 2 6-2 Remington 9 3-6 Valencia (2) N/A RC Reclaim Water 7 3-8 Pelican 1 5 3-9 Club 9 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 events,the Basin 6 TP concentration (0.16 mg/L)dropped back below Basin 3 concentrations and has returned to historical values measured at this site. FIGURE 2 Ammonia and Nitrate-Nitrite Concentrations by Basin in August 2017 Pelican Bay Stormwater Lakes Water Quality Monitoring Program:August 2017 Data Review 0.40 0.35 030 0.25 020 TE0 0.15 f 0 10 0.05 ■ 0.00 Basir,1 Basin 2 Basin 3 Basir:4 Basin 5 Basin 6 ON(mgjt} ■Ammonia(mgJlf 3 Nitrate_Nitrite tmg,1L) The average TP concentrations at Basin 4 for the August sampling event had only a minor deviation of approximately 18 percent when compared with values observed during the May 2017 event. Basins 1 and 6 average TP decreased by approximately 2 and 43 percent, respectively.The TP concentrations in Basins 2,3 and 5 varied significantly and increased by 45 percent, 25 percent and 91 percent, respectively.With the exception of Basins 1 and 4,the average TP values exhibited large increases,while the average TP values for all other basins returned to previous historical average levels. Figure 3 shows that Basins 1 arid 2 are comprised of nearly equal parts orthophosphate and organic phosphorous while Basins 3,4 and 6 are dominated by orthophosphate. Basin 5 is dominated by organic phosphorus.The average concentration of orthophosphate observed in all basins ranged from 0.05 to 0.20 mg/L. Basin 3 had the highest average orthophosphate value,calculated to be 0.20 mg/L,or 71 percent of the average TP concentration,with Basin 3 also having the highest single sample orthophosphate concentration of 0.35 mg/L,or 76 percent of the TP concentration. Basin 6 had the largest ratio of average orthophosphate to organic phosphorous at 77 percent. Lakes that have higher ratios of orthophosphate to organic phosphate can be considered to potentially reflect a more direct influence from landscape fertilizer application practices. Higher concentrations of orthophosphate are more conducive to producing algal blooms. The reclaimed water(RC)sampling location used for irrigation had a TP concentration of 2.09 mg/L in August 2017.This together with fertilizer applications within Pelican Bay may be potential contributing sources of the phosphorus load to the stormwater lakes. PS ICA',EAr 5-:,RMWATER LAKES WATER QUALITY MONITORING PROGRAM:AUGUST 2017 SAMPLING EVENT DATA REVIEW FIGURE 3 Average Total Phosphorus Concentrations by Basin in August 2017 Pelican Bay Stormwater Lakes Water Quality Monitoring Program:August 2017 Data Review 0.30 4.25 to E 0.20 Ail i O s 0.15 0. VI 0 s c,- 010 O0,,F- 0,05 III ilk IIII 0o a Basin 1 Basin 2 Basin 3 Basin 4 Basin 5 Basin 6 Organic Phosphorus(mg/L) Orthophosphate(mg/L) To assess the variability of the TP values at the different sampling locations within each basin,box plots were developed to compare measured TP. Box plots,shown in Figure 4, are a graphical method for summarizing data variability. For a data set representing all of the TN values for a given basin,the median value is identified along with various measures of data variability within the basin(maximum and minimum values as well as the 75`h and 25`h percentile values). If extreme outlier values are present,they generally are excluded from these evaluations of variability, but are shown graphically as indicated in Figure 4.Generally, the median values are the key point of comparison when assessing differences across data sets (in this case, basins). Data sets where the variability bars from the 25th to the 75th percentile values are similar would typically not be considered significantly different from each other. FIGURE 4 Explanation of the Features of a Box and Whisker Plot Pelican Bay Storm water Lakes Water Quality Monitoring Program:August 2017 Data Review X -�-•.. Outlier -----MAXIMUM c a u -it--03(75"Percentile) c 0 U .s—MEDIAN 5 E 0 m is 0 -.r--01 (25"Percentile) r _ s-----MINIMUM Sampling Location 5 Figure 5 compares the six Pelican Bay Stormwater Lakes basins based on the August 2017 TP results. Basin 3 had the greatest range of variability of 0.31 mg/L as well as the highest median value at 0.25 mg/L. Basin 1 had a minimum outlier value of 0.044 mg/L,while Basin 2 had a max outlier value of 0.25 mg/L at station 2-04, (Basin 2, Lake no. 12). Basin 1 had the lowest median value at 0.096 mg/L and showed the smallest range of variability at 0.06 mg/L. Basin 6 consists of a single sample,which is not sufficient for statistical analysis. FIGURE 5 Variability of TP Results per Basin for August 2017 Pelican Bay Storm water Lakes Water Quality Monitoring Program:August 2017 Data Review 0.50 - Max Outlier Min Outlier 0.45 - 0.40 - 0.35 - 0.30 Z5 0.25 - - ci t 0.20 - 0.15 - I - F- 0.10 - 1 0.05 - 1 1 0.00 , --- Basin 1 Basin 2 Basin 3 Basin 4 Basin 5 Basin 6 Copper Concentrations Copper monitoring in the Pelican Bay Stormwater Lakes consists of analysis of surface water samples for total recoverable copper. Figure 6 presents the average copper concentrations for each basin.The average copper concentrations in August 2017 for all the basins ranged from 10 to 25.5 micrograms per liter(µg/L). Basin 4 had the highest average copper value (25.5 pg/L),and Basin 4 had the highest single sample lake concentration for this event(87.6 pg/L) measured at station 4-08 (Basin 4, Lake no. 14). Basin 1 had the lowest average copper concentration (10.0 pg/L)and the lowest single sample concentration(2.1 pg/L) measured at station 5-07 (Basin 5, Lake no. 11). Data from Basin 6 was limited to a single sample(4.1 pg/L) so an average value could not be calculated. A decline in total recoverable copper concentrations was observed in all basins except Basin 6 when compared to the May 2017 sampling event,with decreases ranging from 6 to 68 percent.Compared to the same season last year(August 2016), Basins 1 through 4 decreased significantly in recoverable copper concentration while Basin 5 slightly increased and Basin 6 significantly increased,an approximately 127 percent increase compared to August 2016. Basins 1 and 3 were almost half the copper concentrations from those measured in 2016. 6 PELICAN BAY STORMWATER LAKES WATER QUALITY MONITOR:NG PROGRAM.AUGUST 2017 SAMPLING EVENT DATA REVIEW FIGURE 6 Average Copper Concentrations by Basin in August 2017 Pelican Bay Stormwater Lakes Water Quality Monitoring Program:August 2017 Data Review 30.0 7.7 e 75.0 0 o• 70.0 <`J 0.4 Basin 1 Basin 2 Basin 3 Basin 4 Basin 5 Basin 6 To assess the variability of the copper concentrations at the different sampling locations within each basin, box plots were developed to compare measured total recoverable copper. Figure 7 compares the six Pelican Bay Stormwater Lakes basins based on the August 2017 copper results. Basin 4 had the greatest range of variability from 4.0µg/L to 87.6µg/L. Basin 4 had an outlier value 87.6 µg/L and had the highest median value at 25.9 ug/L. Basin 1 and Basin 5 also had maximum outliers at 23.2 µg/L and 53.1µg/L, respectively. Basin 1 had the lowest median value of 11.3 µg/L. Basin 6 consists of a single sample,which is not sufficient for statistical analysis. The surface water quality standard for copper in the State of Florida's Class Ili freshwater lakes is a calculated value and varies based on water hardness.This standard is not directly applicable to the Pelican Bay Stormwater Lakes since they are man-made lakes designed to treat stormwater and manage runoff. FIGURE 7 Variability of Copper Results by Basin in August 2017 Pelican Bay Starmwater Lakes Water Quality Monitoring Program:August 2017 Data Review 100 - Max Outlier -Min Outlier 90 - 80 - s a`5 70 - ca_ U 60 - • 50 - co > 40 - a • 30 -cc -- -- 20 - 4 ~ - 10 - rjj 1 0 T-- Basin 1 Basin 2 Basin 3 Basin 4 Basin 5 Basin 6 However,the calculated values provide a reference value for comparison with the monitoring results. Hardness for the August monitoring in the Pelican Bay stormwater lakes ranged from 65 up to 216 mg/L calcium carbonate(CaCO3).Applying this value to the formula provided in Chapter 62-302 of the Florida Administrative Code(Ch. 62-302, F.A.C.),yielded a copper reference value of 18.0 pg/L.Water quality within 7 of the 29 stormwater lakes at Pelican Bay in August 2017 reflected concentrations above this copper reference value.This is 8 fewer lakes above the copper reference level than assessed during the May 2017 event and 14 fewer lakes than the February 2017 event. Table 2 summarizes the August 2017 sampling results by basin showing both the average copper concentrations for each basin,as well as the range of copper concentrations by sample station.Twenty-six of the 29 stations had copper concentrations of 25µg/L or less,approximately 90 percent of the sample sites.Three of the basin sample sites,or 10 percent, had concentrations ranging from 26 to 100 pg/L,with no sites recording average levels over 100 pg/L. In November 2016,43 percent of the sample stations were less than 25 pg/L,and 14 percent of the stations were measured at 100 pg/L or greater.This distribution of total recoverable copper has shifted to lower concentrations compared to last year,a clear and improving trend in lower copper levels. Comparison of August 2017 Results to Historical Monitoring Data The historical monitoring data from November 2011 through August 2017 were compiled and analyzed to generate basin-level means for all parameters monitored over the period of record.The means for each basin in each quarter were used to generate time series plots for TN,TP,and total recoverable copper to compare the current basin concentrations to the entire period of record.These time series plots allow a comparison of the August 2017 data to the historical records since November 2011.The number of lakes monitored was reduced from 45 to 29 lakes during December 2014. TABLE 2 Distribution of Basins by Copper Results in August 2017 Pelican Bay Storm water Lakes Water Quality Monitoring Program:August 2017 Data Review Basin Stations with Copper Concentrations,in tg/L Basin Avg. 418/0 <12 13-25 26-50 51-75 76-100 101-125 >125 1-03 1-04 1 10.0 1-05 1-06 2-01 2-02 2 11.8 2-03 2-04 2-05 2-06 3-04 3-01 3 10.9 3-05 3-09 3-06 3-08 4-04 4-02 4-10 4-08 4 25.5 4-06 4-07 5-05 5-01 5-02 _ 5 16.0 5-07 5-10 5-08 6 4.1 6-02 8 PELICAN SAY STORM WATER LAKES'DATER QUiAJTY MONItORISG PROGRAM:.AJG..ST 2017 SAMPLING EVENT DATA REVIEW Rainfall contributions to the stormwater lakes and watershed have a potentially significant effect on lake water quality and residence time. For this reason, historical rainfall data were obtained from South Florida Water Management District's DBHYDRO database. Rainfall data was obtained from COCOl_R,database key D0535,with Latitude 26°15'22.3"N and Longitude 81°46'47.3"W,which is located near the spillway on Cocohatchee canal at Palm River Rd. This rain gauge is managed by the South Florida Water Management District. The rainfall records for the C0001_R site for the period of November 1,2011 to August 31,2017 were used for the evaluation of rainfall impacts on the collected water quality parameters. Rainfall data previously collected from BCBNAPLE was replaced with COCOl R data to maintain a consistent dataset. Figure 8 presents a time series plot of basin mean TN concentrations for this period of record (November 1, 2011 to May 31, 2017) but does not include TN data for August 2017 due to the hurricane.A declining trend in TN is evident from November 2011 to August 2013. From November 2013 to May 2015,the mean TN values trended upwards with peak values noted in February 2015.Since February 2015,the basin averages have been decreasing,and have returned to levels comparable to events prior to March 2013.Typically, Basins 1,5 and 6 have lower values than Basins 2,3,and 4. Changes in nitrogen observed in each basin are attributable to complex chemical and biological interactions and seasonal factors,such as variation in rainfall and associated runoff inputs,along with fertilization practices and schedules. In addition,the discontinuation of algaecide can influence the nitrogen cycle by changing the environmental factors that influence the uptake and recycling of nitrogen.All basins showed similar ranges in TN levels before August 2013, but TN concentrations started varying significantly once the use of copper sulfate was terminated.The stormwater lakes are designed to retain the first flush of rainfall runoff and control direct discharge of nutrients to Clam Bay. FIGURE 8 Basin Average Total Nitrogen Time Series Through May 2017(August 2017 data not included) Pelican Bay Storm water takes Water Quality Monitoring Program:August 2017 Data Review 6.0 6 5.5 5.0 5 4.5 4.0 4 — 0 3.5 3.0Ts 3 .E zcc 25 O 2.0 , 0.5 1I�d�C,6 .,., r161 l�l�. h ��'I Ilk 1.1141 �1�..ii�0.0 � �� 0 +-i N N N N M M mM C,+' ' C ='1 �7 ,f stl U 'l� 4^. iU N. N- N. e-1 o u — 0 t o c, C c1 o v a j = Z 2 Z g < Z u- 2 < Z 2 < z g < z g < Rainfall 1 -f-2 3 - 5 6 Figure 9 presents a time series plot depicting the basin mean TP concentrations for the six basins for the period of record.All basins show a variable trend over time since 2011 with low TP levels in most basins during February 2014.Since August 2014,Basins 1,2,4,and 5 appear to have stabilized with average TP concentrations between 0.05 to 0.20 mg/l.Basin 3 continues to exhibit elevated concentrations ranging from approximately 0.23 to 0.36 mg/L. Basin 6 exhibited an elevated TP concentration(0.28 mg/L)during May 2017,but in August 2017 the levels have returned to historical levels when compared with previous sampling events. The majority of phosphorus present is inorganic which is likely associated with sediment cycling between that contained within the sediment at the bottom of the lakes and soluble phosphorous in the water column.TP typically accumulates in settled sediment and cycles back into the water column increasing TP discharges from the lakes between storm events.As a result,concentrations of phosphorus remain high even during times of low rainfall,and.stormwater lakes generally provide little TP removal due to phosphorus solubilization of settled sediment.The levels observed within these stormwater lakes are likely in equilibrium with sediment cycling and are not expected to change in the near term even if TP loads were reduced. Figure 10 presents a time series plot depicting the basin mean copper concentrations for the period of record for the 6 basins.The significant decrease in average copper concentration after August 2013 appears to be a direct result of discontinued use of copper-based algaecides. The average concentration of copper shows an overall improvement from August 2013 to August 2017.Similar to TP,Basins 3 and 4 show elevated copper during dry periods,likely associated with sediment cycling. During this August 2017 event,every basin decreased in average copper concentration over the previous quarter.Only 10 percent of sampling sites had a measured copper concentration of over 26µg/L,with all of the values below 100µg/L. Copper levels overall appeared to have reached an equilibrium with sediments accumulated in these lakes and fluctuations in concentrations may be associated with perturbations of the sediment layer.Windy days, fountains,and general maintenance within the lakes might create some disturbance of the sediment which results in changes in copper concentrations in the water column. io PELICAN BAY STORMWATER LAKES WATER QUALITY MONITORING PROGRAM AUGUST 2017 SAMPLING EVENT DATA REVIEW FIGURE 9 Basin Average Total Phosphorus Time Series for Period of Record Pelican Bay Stormwater Lakes Water Quality Monitoring Program:August 2017 Data Review 0.60 6 0.55 0.50 5 0.45 0.40 4 . 0.35 c 0 0.30 3 70- 0t.n .25 a 00.20 � tI ; 2a 0.15 IA .: .,. irk; 4 -4 -„,- t,„ II'II if 'Lli' Cl„ 4t0 ..P 4iii - Viti IL'-''0.10 4--t L � , 0.05 # .i{{r` I 1 iii .l dl�,h� e� I l i 1i R.11�Ii 111II 1 r 11 I. 0.00 0 .-i N N N NI M en M m ay C' .t, L'7 .-n 4^1 s.^, i4 s j Z 'C..s' I-- h t-- e-1 e-i .-i .-; e-4 .-i e-d .-1 ed e-1 e-4 r, r# e-+ . e-1 .-i ,- ,-{ e-i e-1 e-I 7 6 7 t`..�. 7 .. A C: L'J t5 O Tta � Q as � O d3 4 = O ^; � = i7 fit Z L.- 2 a z g z L 2 < z '.- 2 < z Iw 2 < z w- 2 INIIII Rainfall 1 -111-2 -- -- 3 4 --5 --4-,---6 FIGURE 10 Basin Average Total Recoverable Copper Time Series for Period of Record Pelican Bay Stormwater Lakes Water Quality Monitoring Program:August 2017 Data Review 500 6 Discontinued 450 use of CuSO4in 400 August 2013 5 t 350 4 C ,• 300 .cco 75 250 '%, 3 - ✓ I cc > 200 1 _ 2 ig 1 it O 100 4 liy i . 1 50 \ it I I "ter ø11 II 1iba ` mi .-i N N N N M rn rn :e'7 nr c'. 'C!' . Ira In 4^ v't t0 t3 L3 iJ N r� N e-1 e-1 .i r{ e-1 r' .-1 .-1 e-/ -I e-t e-1 .-I r3 r} .-f e-4 e-1 .-t e-f ea rt . • e ? .L > GCT t... 7 .0 74 CA > so 7, to > .L >- to > ^ T to O to MIN Rainfall 1 -0-2 _.3 -*-4 -5 -t-i- 6 Reclaimed Water The historical monitoring data of the reclaimed water samples from November 2011 through August 2017 were compiled and analyzed to compare reclaimed water quality to the average basin water quality of the stormwater lakes. Figure 11 presents a time series plot of the reclaimed water measured TN concentrations compared to the basin mean TN concentrations for the period of record,excluding August 2017 data when TN data were not available due to the hurricane.The discussion here presents data through May 2017 as a reference.There is no trend evident for TN from November 2011 to May 2017, however,the average reclaimed water TN concentration for the period of record is 6.78 mg/L,which is greater than the average TN value for each of the basins.This comparison to reclaimed water does not take into account the temporal lag time for applied reclaimed water to reach the stormwater lakes whether through runoff or groundwater infiltration. FIGURE 11 Reclaimed Water and Basin Average Total Nitrogen Time Series Through May 2017 Pelican Bay Storm water Lakes Water Quality Monitoring Program:August 2017 Data Review r 12.0_ 10.0 10.oa • 8.0 8.0 5.0 6.0 c' • 4'0 4.0 . 2.0 ., • 0.0 0.0 N N N N m tr rr r.'S c C c v i.f; N tr, t.0 kip cU t:.) N r. N e-1 e-! e-i e-i e-i ei e-i . . e-i e: e-1 e-1 e ? ..-4 e-1 r-4 e-1 o 0 a: 0 4: 0 G: r z 0 U 0 U Z -id-1 -0-2 3 -- .4 . 5 Li 6 —.—PC Figure 12 presents a time series plot depicting reclaimed water TP concentrations compared to the basin mean TP concentrations for 6 basins for the period of record.There is no evident trend observed for TP concentration in reclaimed water from November 2011 to August 2017. The average reclaimed water TP value for the period of record is 2.09 mg/L,which is significantly higher than the average TP concentration in each of the basins. Historically,the average composition of TP in reclaimed water is approximately 90 percent orthophosphate. PELICAN BAY STORMWATER LAKES WATER QUALITY MONITORING PROGRAM.AUGUST 2017 SAMPLING EVENT DATA REVIEW FIGURE 12 Reclaimed Water and Basin Average Total Phosphorus Time Series for Period of Record Pelican Bay Storm water Lakes Water Quality Monitoring Program:August 2017 Data Review 2.0 3.5 Ij LS . 3.0 .! 1.6 1.4 2.5 1.2 _. 2.0 0 1.5 0.8 E 0.6 - 1.0 4.4 iti a �,, 05 C (y , 0.2 T - 0.0 1-1 N N N N MI M m it C C C 'C' Ln i!5 in I•tl tz t13 Lc t0 r• r• r-- .--L .--I r-i r-I r? V.4 c-f r-i ri ,-i ri r-1 .-I +-f .•.i r-1 <-1 e-fi — t-i r-1 .-I a--1 > . - it > - >- 40 > _^.. >- tLS ? -6 S^ C.0 > _.6 6D > .271 ;- t.11 --4-1 - --2 3 4 .. ..5 il, 6 -40—RC Figure 13 presents a time series plot depicting the reclaimed water mean copper concentrations for the period for comparison with the concentrations of the six basins.The data clearly indicate reduction in copper in 2013,when application of copper-based algaecides ceased.The average total recoverable copper for each of the basins,except for Basin 6,is typically much greater than the total recoverable copper measured in reclaimed water.Since May 2013,measured copper in the reclaimed water has been less than 8µg/L with the exception of February 2016.The average reclaimed water copper concentration from May 2013 to August 2017 was 3.57 Rg/L. In August 2017,the reclaimed water total recoverable copper concentration was below this average at a value of 2.02 sg/L. FIGURE 13 Reclaimed Water Total Recoverable Copper Time Series for Period of Record Pelican Bay Storm water Lakes Water Quality Monitoring Program:August 2017 Data Review 500 300 450 250 T 400 \to ^' Q. 350 - 200 f 300 1 t 250 ' 150 I- L 200 f. 100 Y. i 150 +. 9 .. --. 100 . .. 50 50 R. c Q - ,tet < Y.• _„it ., ., ,--t N N N N m m m m - -• C - to sr) al t.f) t3 LO t7 LA N N N. r-i rf e-1 rd 71 r-1 r-1 ri r•! - 1•-1 .-s - <-4 <A ri e-f ri .-•I ri ri e-I e-i - sr & o 0 ra 4 0 6 1 u- u. d z u- Q z u- Q Z L- 2 Q -A-1 2 3 -0-4 izi, 5 id 6 -*—RC 13 Observations and Recommendations Based upon a review of the August 2017 monitoring results,the following observations were made regarding the water quality trends within the six Pelican Bay stormwater lakes. Nutrients have shown little response over the past year.The lakes continue to experience nutrient concentrations at hypereutrophic levels.While some lakes have experienced slightly lower levels since the last quarter,the improvements are not statistically significant. Basin 6 showed a significant increase in TP levels in February 2017 which cannot be explained and may be related to physical perturbations of the settled sediment within the lakes in this basin.TP levels have since declined and returned to levels previously recorded in this basin. Total recoverable copper concentrations remain significantly lower than those measured prior to August 2013 when copper sulfate use for algae control ceased.All lakes experienced a decrease in average total copper concentration in August 2017 compared to the preceding quarter,well below elevated historical concentrations.This trend shows continuing improvement in copper levels in the stormwater lakes. Seasonal patterns in copper concentrations appear driven but rainfall.August is the peak of the normal wet season when stormwater flows dominate the water balance,thereby diluting concentrations of conservative ions. February is during the driest period,when groundwater inputs dominate with greater inorganic ion concentrations. However,copper concentrations appear to have reached an equilibrium with sediment cycling but a declining trend is notable. While an overall decline in copper concentrations has been observed in the lakes, copper concentrations continue to be significantly above the Florida Class Ill water body standard.While state water quality criteria are not directly applicable to the stormwater lakes,the FDEP has expressed concern that stormwater discharges to Clam Bay may be having an effect on estuarine water quality for copper. Long-term data indicate that both phosphorus and copper are cycling from lake sediments and have reached equilibrium. Controlling phosphorus cycling could reduce the potential for algal blooms. Planting littoral vegetation would promote additional treatment and reduce the overall nitrogen load to the bay.