Task 20 Deliverable: Final Report 1 · Executive summary Water & Soil Solutions, LLC (WSSLLC) has deployed an approximately 523‐acre Floating Aquatic Vegetative Tilling (FAVT) wetland

ImplementationofFloatingAquaticVegetativeTillingTechnologyintheCaloosahatcheeRiverWatershed

Task20Deliverable:FinalReport

Site1

Preparedfor:FloridaDepartmentofAgricultureandConsumerService

(FDACS)

Contract#021121

Preparedby:Water&SoilSolutions,LLC

Loxahatchee,FL

August18,2015

2

TableofContents

ListofFigures..............................................................................................3 ListofTables................................................................................................5 Executivesummary...................................................................................6 Introduction.................................................................................................9 FAVTSystemUnitProcesses.......................................................................................................................11

Optimization&MonitoringResults...................................................12 WaterChemistryintheFAVTsystem......................................................................................................12

Characterization of inflow and outflow water chemistry ..................................................... 15 TP and pH monitoring at cell inflows and outflows ............................................................. 21 Internal water chemistry monitoring of Cells 1 and 2 .......................................................... 28

FloatingandSubmergedAquaticVegetationSurveys.....................................................................30

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ListofFiguresFigure 1. Project location within the watershed (Source – Caloosahatchee River Watershed

Protection Plan January 2009). ............................................................................................... 10

Figure 2. Internal water quality sampling locations in Cells 1 and 2 of the FAVT facility during June 2015. ............................................................................................................................... 14

Figure 3. TP concentrations in the Caloosahatchee FAVT system inflow and outflow streams, for the POR 9/15/14 (initiation of system discharge) through 6/30/15. Monitoring was conducted on a weekly basis. ................................................................................................................... 17

Figure 4. SRP concentrations in the Caloosahatchee FAVT system inflow and outflow streams, for the POR 9/15/14 (initiation of system discharge) through 6/30/15. Monitoring was conducted on a weekly basis. .................................................................................................. 17

Figure 5. DOP concentrations in the Caloosahatchee FAVT system inflow and outflow streams, for the POR 9/15/14 (initiation of system discharge) through 6/30/15. Monitoring was conducted on a weekly basis. .................................................................................................. 18

Figure 6. PP concentrations in the Caloosahatchee FAVT system inflow and outflow streams, for the POR 9/15/14 (initiation of system discharge) through 6/30/15. Monitoring was conducted on a weekly basis. ................................................................................................................... 18

Figure 7. TN concentrations in the Caloosahatchee FAVT system inflow and outflow streams, for the POR 9/15/14 (initiation of system discharge) through 6/30/15. Monitoring was conducted on a weekly basis. .................................................................................................. 19

Figure 8. Nitrate+nitrite (NOx) concentrations in the Caloosahatchee FAVT system inflow and outflow streams, for the POR 9/15/14 (initiation of system discharge) through 6/30/15. Monitoring was conducted on a weekly basis. ....................................................................... 19

Figure 9. Ammonia-N concentrations in the Caloosahatchee FAVT system inflow and outflow streams, for the POR 9/15/14 (initiation of system discharge) through 6/30/15. Monitoring was conducted on a weekly basis. ........................................................................................... 20

Figure 10. Alkalinity in the Caloosahatchee FAVT system inflow and outflow streams, for the POR 9/15/14 (initiation of system discharge) through 6/30/15. Monitoring was conducted on a weekly basis. ........................................................................................................................ 20

Figure 11. pH in the Caloosahatchee FAVT system inflow and outflow streams, for the POR 9/15/14 (initiation of system discharge) through 6/30/15. Monitoring was conducted on a weekly basis. ........................................................................................................................... 21

Figure 12. Surface water TP concentration and pH at the inflow and outflow of Cell 1 of the Caloosahatchee FAVT system. Monitoring was conducted on a weekly basis from November 2014 through June 2015. ......................................................................................................... 24



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Figure 15. Mean surface water TP concentration (±1 standard deviation) at the system inflow (=Cell 1 inflow), Cell 1 outflow (=Cell 2 inflow), Cell 2 outflow (=Cell 3 inflow), and system outflow (=Cell 3 outflow) of the Caloosahatchee FAVT system. Values were calculated from data collected during 34 weekly monitoring events from November 2014 through June 2015. .................................................................................................................. 27

Figure 16. Mean surface water pH (±1 standard deviation) at the system inflow (=Cell 1 inflow), Cell 1 outflow (=Cell 2 inflow), Cell 2 outflow (=Cell 3 inflow), and system outflow (=Cell 3 outflow) of the Caloosahatchee FAVT system. Values were calculated from data collected during 34 weekly monitoring events from November 2014 through June 2015. ................... 27

Figure 17. Interpolated spatial TP profiles in Cells 1 and 2 (top), and individual data points for SRP (not interpolated) for Cells 1 and 2 (bottom), for the internal water quality monitoring event in Jun 2015. Note that most SRP values in Cells 1 and 2 were below the detection limit, so no interpolation of these data was performed. ................................................................... 29

Figure 18. Very dense mat of Eichhornia crassipes (water hyacinth) and Pistia stratiotes (water lettuce) in Cell 1 ...................................................................................................................... 32

Figure 19. Time-series for FAV species within Cells 1 and 2 depicting the percent of stations that was moderately dense or greater for each species. ................................................................. 33

Figure 20. Time-series for FAV species within Cells 1 and 2 depicting the percent of stations that each species present. ............................................................................................................... 34

Figure 21. Mixed species mat with Eichhornia crassipes (water hyacinth) and Pistia stratiotes (water lettuce) in Cell 1. .......................................................................................................... 35

Figure 22. Relative cover of the FAV species Eichhornia crassipes and Pistia stratiotes in Cells 1 and 2 of the Caloosahatchee wetland during October and December 2014 and February, April, and June 2015. The black dots represent the observation locations, and the six semi-quantitative density categories are shown in the legend. ........................................................ 36

Figure 23. Najas guadalupensis (southern naiad) growing near the outflow of Cell 3. ............... 38

Figure 24. Mixed SAV assemblage containing Utricularia sp. (bladderwort) and other species in Cell 3. ...................................................................................................................................... 39

Figure 25. Hydrilla verticillata, an invasive SAV species, at the Cell 2 culvert. ......................... 39

Figure 26. Time-series for SAV species within Cell 3 depicting the percent of stations that stations that was moderately dense or greater for each species. ............................................. 40

Figure 27. Time-series for SAV species within Cell 3 depicting the percent of stations that each species is present. .................................................................................................................... 41

Figure 28. Relative cover of Najas guadalupensis, Utricularia spp., and Hydrilla verticillata in Cell 3 of the Caloosahatchee wetland during October and December 2014, and February, April, and June 2015. The black dots represent the observation locations, and the six semi-quantitative density categories are shown in the legend. ........................................................ 42

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ListofTables Table 1. Analytical methods used for laboratory analysis of surface water sampled for the

Caloosahatchee FAVT project. Method detection limits (MDL) are shown for each chemical parameter analyzed. ................................................................................................................ 14

6

ExecutivesummaryWater& Soil Solutions, LLC (WSSLLC) has deployed an approximately 523‐acre Floating

AquaticVegetativeTilling(FAVT)wetlandtreatmentfacilityintheHendry‐HilliardWater

ControlDistrict (HHWCD) in theEastCaloosahatcheeRiver Sub‐Watershed southwestof

LakeOkeechobee.Thepurposeoftheprojectistocosteffectivelyremovephosphorus(P)

and nitrogen (N) from regional canals, including surface waters of the HHWCD and the

Caloosahatchee River (C‐43 Canal), using the patented FAVT technology in aman‐made

flow‐throughtreatmentmarsh.

FAVTsystemsutilizeanovelapproachtoenhanceNandPremoval fromsurfacewaters.

Thetechnologyusesthedirectassimilationofnutrientsfromthewatercolumnthroughthe

use of floating plant roots (as compared to plants rooted in the soil) and, rather than

periodically harvesting the plants (which is costly and inefficient due to the highwater

contentof thevegetation),allof thebiomass israpidly incorporateddirectly intothesoil

via tilling during the dry season. FAVT systems therefore operate similarly to a

conventional treatmentwetland by storing P in the soil, but they accomplish P removal

moreefficientlyandatasignificantlyfasterrate. Atthissite,FAVspeciescommontothe

adjacentcanals,namelyEichhorniacrassipes (waterhyacinth)andPistiastratiotes (water

lettuce),areutilizedinthefronttwocells,whileNajasguadalupensis,Utriculariaspp.,and

otherspeciesofsubmergedaquaticvegetation(SAV)dominatethebackend(Cell3)asa

final,“polishing”,componentoftheFAVTsystem.

Thesystembecamefullyoperational inSeptember2014,receivingregionalsourcewater

anddischargingthroughtheoutflowculvertsbeginning9/15/14.Subsequentmonitoring

of system inflow and outflow water chemistry was conducted on a weekly basis.

Monitoring results through June2015showthat systemoutflowTPconcentrationswere

consistently lower than inflow TP concentrations, despite highly variable inflow TP

concentrationsrangingaslowas35µg/L,duringthedryseason,andashighas325µg/L,

during thewet season. Outflow TP concentrations ranged from 22 to 62 µg/L, with the

highest concentrations occurring during the first two months of system discharge

(September‐October 2014). During the remainder of the monitoring period outflow TP

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concentrationsbecame increasinglystable,averaging29µg/Landranging from22to38

µg/L. OverallmeanTPconcentrationsintheinflowandoutflowstreamswere74and33

µg/L, respectively.Soluble reactiveP (SRP)concentrationswereconsiderably reduced in

theoutflowstream,fromanaverageof24µg/Lattheinflowto2µg/Lattheoutflow.On

average,SRPaccountedfor33percentofTPintheinflowstream,butonly7percentofTP

in the outflow stream. The reduction in SRP concentration is assumed to be largely

attributable to plant uptake. Dissolved organic P (DOP) and particulate P (PP)

concentrationswerealsoeffectivelyreducedbytheFAVTsystem.

TPmonitoringattheinflowandoutflowofeachofCells1,2and3beginninginNovember

2014indicatedthatmostofthePremovalhasoccurredacrossCells1and2.Furthermore,

TPconcentrationsattheCell1and2outflowsdecreasedovertime,whileconcentrationsat

the Cell 3 outflow showed little or no overall change over time. This could be due to a

numberoffactors,includingreleaseofsoilPtotheoverlyingwaterinCell3,enhancedby

decreasing Cell 2 outflow concentrations, and a limited capacity for P removal via plant

uptakeduringestablishmentofrobustSAVcommunitiesinCell3.

Internal monitoring of TP and SRP at 15 sites within Cells 1 and 2 during June 2015

indicated that P removalwithin thewetland followed a predictable spatial pattern,with

gradualreductionsinTPconcentrationsoccurringinCell1asdistanceincreasedfromthe

inflowthroughthecell.TPlevelsinthebacktwo‐thirdsofCell2wereextremelylow,at15

µg/Lor less.Theobserved spatial trends inTP suggest thatmuchof thepumped inflow

waterpreferentiallypassesalongtheeasternsideofCell1.Thebioavailablephosphorous

(SRP) results,manyofwhichwerebelow thedetection limitof2µg/L, also support this

hypothesis,with highest SRP levels observed along the easternportion of the flowpath.

PlantcoveranddensityalsomayaffecttheobservedspatialpatternsinPremoval,andthis

willbeatopicoffutureassessmentatthisfacility.

Total N (TN) concentrations were not effectively reduced during the 2014‐2015

monitoring period. The overallmean outflow TN concentrationwas slightly higher than

meaninflowTN(1.48vs.1.39mg/L,respectively).NearlyalloftheTNloadtothesystem

was inorganic form, representingasubstantialpoolofN that isnot readilybioavailable.

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Although some decomposition of organic N, and subsequent removal of inorganic N, is

likelyoccurring in thewater column, it is alsopossible that releaseofN from the soil is

serving to maintain elevated N concentrations in the overlying water during the early

stagesofoperationofthisrecently‐floodedsystem.Waterchemistrymonitoringduringthe

upcomingyearwill likelyprovideagreaterunderstandingof theshort‐and long‐termN

removalcapacityofthetreatmentsystem.

In order to evaluate vegetation growth and health, visual assessments of speciation and

areal coverage (i.e., relative abundance) of FAV (Cells 1 and 2) and SAV (Cell 3) were

performedonaroutinebasisatstations locatedonapre‐determinedgridpatternacross

Cells 1 (21 stations), 2 (33 stations) and 3 (53 stations). These surveyswere conducted

monthlyfromOctober2014throughJune2015.Resultsofthesurveysindicatedthatdense

growthofwaterhyacinthincreasedincoveragefrom56%to95%inCell1andfrom33%

to93%inCell2,withaslightdecreaseincoverageobservedattheendofthemonitoring

period.DensegrowthofPistiaoccurredat22%ofthestationsinCell1and13%ofstations

inCell2duringtheOctobersurvey,andreachedamaximumcoverageofonly30%inCell1

and19%inCell2, inFebruaryandMarch,respectively,beforedecreasingslightlyduring

theremainderoftheperiod.AmongeightSAVspeciesmonitoredinCell3,Utriculariaand

Najas (during later surveys) were by far the most commonly occurring. Utricularia

maintained a relatively dense growth across the majority of Cell 3 during the entire

monitoring period, whileNajas increased from sparse coverage in October to relatively

dense growth in 70% of Cell 3, mostly toward the inflow and outflow regions.Hydrilla

verticillataappearedinNovember,increasingincoverageslowlythroughearlyspring,and

morerapidlythereafter,andattaininganestimatedcoverageof45%ofthetotalareaofthe

Cell 3 during the June2015 survey. Continuedmonitoring of both SAV andFAVwill be

performedinFY2016,inordertoenhancesystemoperationsandmanagementpractices,

and to facilitate our understanding of spatial and temporal patterns in TP removal

performance.

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IntroductionWater&SoilSolutions,LLC(WSSLLC)hascompletedthefirst fullyearofoperationofan

approximately 523‐acre Floating Aquatic Vegetative Tilling (FAVT) wetland treatment

facilityintheHendry‐HilliardWaterControlDistrict(HHWCD)intheEastCaloosahatchee

River Sub‐Watershed southwest of Lake Okeechobee. The watershed is located in the

NorthernEvergladeswestofLakeOkeechobee.Theprojectsiteispartofalargeparcelof

privateland(Sections18&19/Township44South/Range32East)onthesouthernside

of the Caloosahatchee River (Figure 1). The purpose of the project is to cost effectively

removephosphorus(P)andnitrogen(N)fromregionalcanals,includingsurfacewatersof

the HHWCD and the Caloosahatchee River (C‐43 Canal), using the patented FAVT

technology in aman‐made flow‐through treatmentmarsh. This document encompasses

theFinalReportfortheprojectperiodJuly1,2014throughJune30,2015.

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ProjectSite

Figure1.Projectlocationwithinthewatershed(Source–CaloosahatcheeRiverWatershedProtectionPlanJanuary2009).

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FAVTSystemUnitProcesses

FAVTsystemsutilizeanovelapproachtoenhanceNandPremoval fromsurfacewaters.

ManyspeciesofFAV,suchaswaterhyacinth,areknowntorapidlyassimilateNandP,but

their high nutrient uptake rate can only be sustained if the plants aremaintained at an

optimaldensity.The ideal coverage is usually achievedbyperiodicharvesting; however,

since FAV are predominantly water, mechanical removal of the biomass is costly and

inefficient.FAVTovercomestheseconstraintsbyusingthefollowingoperationalapproach:

(1)theFAVwetlandisoperatedforaninitialgrowingseason,duringwhichtimetheFAV

assimilatenutrientsandgrowtoahighdensity;(2)thewetlandisdrainedduringthedry

season,therebystrandingtheFAVonthesoil;(3)afteranaturaldryingprocess,theplant

material is tilled into the soil togetherwith its associated nutrients; (4) thewetland is

reflooded;and(5)FAVthatarestoredindeeperzonesareusedtorepopulatethewetland

for the subsequent growth period. During this post‐tilling process, water is held in the

wetlandwithoutdischargeforseveralweekstoprovidetimeforthevegetationandwater

columnnutrient levels to equilibrate. It is anticipated that tillingwill beperformedon a

yearlybasis(approximately)attheProjectsite.

FAVTsystemsthereforeoperatesimilarlytoaconventionaltreatmentwetlandbystoringP

inthesoil,buttheyaccomplishPremovalmoreefficientlyandatasignificantlyfasterrate.

Thetechnologyusesthedirectassimilationofnutrientsfromthewatercolumnthroughthe

useoffloatingplantroots(ascomparedtoplantsrootedinthesoil),andallofthebiomass

israpidlyincorporateddirectlyintothesoilthroughtilling.Theprocesstherebyresultsina

reductionofup to80%of landneeded for treatmentascomparedto traditionalwetland

treatment systems. It isexpected that theFAVTsystemswillprovideP reductions in the

rangeof3to15gP/m2‐yr,dependingonthegrowthrateoftheFAV,whichwillbelinkedto

factorssuchas theP loadingrate,speciationofP inthe inflowwaters,andavailabilityof

inorganic N and other macro‐ and micro‐nutrients in the inflow waters. Similarly, N

removalcanbeextremelyhighinFAVsystems(upto250gN/m2‐yr)whenthesupplyof

inorganicNishighintheinflowwaters.AnefforttoestimatetotalPandNmassremoval

bytheEastCaloosahatcheeRiverProjecthasnotyetbeenmadeduetouncertaintiesofkey

underlyingvariables,suchaswateravailabilityandnutrientlevels.

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At this site, FAV species common to the adjacent canals are being utilized, for example,

Eichhornia crassipes (water hyacinth). Maximum growth (and P uptake) rates of this

species occur in the summer, which coincides with the periods of highest runoff flows

availablefortreatment.

Asnotedabove,soilsaretheultimatestoragereservoirforPwithinalltreatmentwetlands.

In conventional, emergent plant based wetlands such as the front‐end cells of the

Everglades Stormwater Treatment Areas (STAs), most of the soil P is associated with

organicmatterwith lesseramounts associatedwithminerals suchas calcium, aluminum

andiron.AnimportantaspectoftheFAVTtillingapproachisthatitacceleratestherateof

transferringnotonlyP,butalsoorganicmatterand inorganicP‐sorbingcompounds into

permanentstorage.

Optimization&MonitoringResultsThegoalofthisoptimizationandmonitoringeffortistocollect,analyzeandreportwater

quality, water flow, vegetation and soil data to facilitate optimization of the East

CaloosahatcheeFAVTsysteminanenvironmentallysoundmannerandinaccordancewith

establishedprotocols.

WaterChemistryintheFAVTsystem

Thesystembecamefullyoperational inSeptember2014,receivingregionalsourcewater

anddischargingthroughtheoutflowculverts,beginning9/15/14.Subsequentmonitoring

ofsysteminflowandoutflowwaterchemistrywasconductedonaweeklybasis.Resultsof

ongoingwaterqualitymonitoringarepresentedfortheperiod9/15/14–6/30/15.

Water samples collected during each event were analyzed for the parameters listed in

Table1,usingstandardmethodsofanalysis.DissolvedorganicP(DOP)andparticulateP

(PP)werecalculatedfromTP,SRPandTSP(DOP=TSP‐SRPandPP=TP‐TSP);totalN(TN)

was calculated as the sum of TKN and NOx‐N. pH was measured on site during each

samplingevent.

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Additionalweeklymonitoring,forTPandpHonly,wasconductedattheoutflowsofCells1

and2(equivalenttotheinflowsofCells2and3,respectively),startinginNovember2014.

The objective of this supplemental monitoring is to evaluate water chemistry changes

withineachofthethreesystemcells.Forthispurpose,thesysteminflowandoutflowdata

representtheCell1inflowandCell3outflow,respectively.

During June 2015, internal monitoring of selected water quality constituents (e.g., total

phosphorus[TP],solublereactiveP[SRP])wasperformedtobettercharacterizethespatial

watertreatmentpatternswithinthefloatingaquaticvegetation(FAV)dominatedportions

ofthewetland(i.e.,Cells1and2).TheinternalwatersamplinggridisshowninFigure2.

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Table1.AnalyticalmethodsusedforlaboratoryanalysisofsurfacewatersampledfortheCaloosahatcheeFAVTproject.Methoddetectionlimits(MDL)areshownforeachchemicalparameteranalyzed.

Figure2.InternalwaterqualitysamplinglocationsinCells1and2oftheFAVTfacilityduringJune2015.

Parameter Method MDL

Total Phosphorus (TP) SM4500‐P F 3 µg/L

Soluble reactive P (SRP) SM4500‐P F/DBE SOP OPO4 2 µg/L

Total Soluble Phosphorus (TSP) SM4500‐P F 3 µg/L

Alkalinity EPA 310.1 3 mg CaCO3/L

Nitrate + nitrite (NOx‐N) EPA/353.2/SM4500 NO3‐F 0.003 mg/L

Total ammonia (NH3+NH4) EPA 350.11 0.020 mg/L

Total Kjeldahl Nitrogen (TKN) EPA 351.2 0.08 mg/L

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Characterizationofinflowandoutflowwaterchemistry

During the September 2014 – June 2015 monitoring period, system outflow TP

concentrationswere consistently lower than inflowTP concentrations (Figure3). Inflow

TPconcentrationswerehighlyvariable,rangingaslowas35µg/L,duringthedryseason

(February 2015), and as high as 325 µg/L, during the wet season. Outflow TP

concentrations ranged from 22 to 62 µg/L, with the highest concentrations occurring

during the first twomonths of system discharge (September‐October 2014). During the

remainderofthemonitoringperiodoutflowTPconcentrationsbecameincreasinglystable,

averaging29µg/Landrangingfrom22to38µg/L.OverallmeanTPconcentrationsinthe

inflowandoutflowstreamswere74and33µg/L,respectively.

SolublereactivePconcentrationwasconsiderablyreducedintheoutflowstream,relative

to inflow concentration (Figure 4). Inflow SRP concentrations averaged 24 µg/L, but

rangedwidely,from6to171µg/L,duringthemonitoringperiod.Incontrast,outflowSRP

concentrationswereconsistentlybelow10µg/L,rangingfromnon‐detectable(<2µg/L)to

7µg/Landaveraging2µg/L.Onaverage,SRPaccountedfor33percentofTPintheinflow

stream,butonly7percentofTPintheoutflowstream.ThereductioninSRPconcentration

isassumedtobelargelyattributabletoplantuptake.

ConcentrationofDOP,whichisnotreadilyavailableforplantuptake,wasslightlylowerin

theoutflowstreamthanintheinflowstreamduringmostofthemonitoringperiod(Figure

5). The overallmean inflowDOP concentrationwas 23µg/L, comparedwith an outflow

mean concentration of 15 µg/L. Inflow DOP concentrations were considerably more

variable,rangingfrom10to66µg/L,relativetooutflowDOPconcentrations,whichranged

from 8 to 25 µg/L. On average, the proportion of DOP as a fraction of total P increased

betweenthesysteminflowandoutflow,from32to46percentofTP,reflectingthelower

bioavailabilityofDOPversusSRP.

ParticulatePconcentrationsdecreasedbetweenthesysteminflowandoutflowduringthe

majorityof themonitoringperiod (Figure6),with inflowandoutflowPP concentrations

averaging 26 and 16 µg/L, respectively. Inflow PP concentrationswere somewhatmore

variable,rangingfrom8to172µg/L,whileoutflowPPconcentrationsrangedfrom2to40

16

µg/L. The stability in outflow PP concentration relative to inflow PP is indicative of

effectivesettlingofparticulatesoverawiderangeofinflowPconcentrations.

DuringtheSeptember‐Junemonitoringperiod,TNconcentrationsintheinflowandoutflow

streamsweresimilar(Figure7),reflectinglittleornonetremovalofNduringthisperiod.

InflowTNconcentrationsrangedfrom1.02to2.19mg/L,whileoutflowTNconcentrations

weremorevariable,rangingfrom0.93to2.30mg/L.TheoverallmeanTNconcentrationin

the outflow streamwas slightly higher than themean inflowTN concentration (1.48 vs.

1.39 mg/L, respectively). Only a small fraction of the TN load to the system was in

inorganicform,eitherasNOx‐Norammonia‐N(Figure8andFigure9).Thelargefractionof

organic N in the system inflow represents a substantial pool of N that is not readily

bioavailable. Although mineralization of this organic N (decomposition of organic N to

ammonia‐N)islikelyoccurringwithinthewetland,itisalsopossiblethataneteffluxofsoil

organicN(includingsoilorganicmatteroriginatingfrommanure)isoccurringduringthe

early stages of operation of this recently‐flooded system. Within the much smaller

inorganic N pool in the system inflow, there is evidence of depletion of NOx‐N either

throughplantuptakeordenitrification, andammonia‐Nviaplantuptakeornitrification.

Thus,itislikelythatnetremovalofTNfromthecombinedsoil‐watersystemhasoccurred,

butthatsurfacewaterTNconcentrationshaveremainedelevatedduetocontinuedsoilN

efflux.Waterchemistrymonitoringduringtheupcomingyearwilllikelyprovideagreater

understandingoftheshort‐andlong‐termNremovalcapacityofthetreatmentsystem.

Alkalinitylevelsintheinflowwateraveraged146mg(asCaCO3)/Landrangedfrom114to

188mg/L, with no obvious seasonal trend observed over the course of themonitoring

period(Figure10). Outflowalkalinityrangedfrom112to165mg/L,andwasalternately

greaterthanorlessthaninflowalkalinity,thoughtheoverallmeanvalue(141mg/L)was

similar to mean inflow alkalinity. Outflow pH was consistently higher than inflow pH

(Figure 11), likely due in part to the consumption of dissolved CO2 by submerged

vegetation(SAV) inCell3of thetreatmentsystem. InflowpHrangedfrom6.8to8.1and

averaged7.3,whileoutflowpHrangedfrom7.2to8.3andaveraged7.7.

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Figure3.TPconcentrationsintheCaloosahatcheeFAVTsysteminflowandoutflowstreams,for the POR 9/15/14 (initiation of system discharge) through 6/30/15.Monitoring wasconductedonaweeklybasis.

Figure 4. SRP concentrations in the Caloosahatchee FAVT system inflow and outflowstreams,forthePOR9/15/14(initiationofsystemdischarge)through6/30/15.Monitoringwasconductedonaweeklybasis.

18

Figure 5. DOP concentrations in the Caloosahatchee FAVT system inflow and outflowstreams,forthePOR9/15/14(initiationofsystemdischarge)through6/30/15.Monitoringwasconductedonaweeklybasis.

Figure6.PPconcentrationsintheCaloosahatcheeFAVTsysteminflowandoutflowstreams,for the POR 9/15/14 (initiation of system discharge) through 6/30/15.Monitoring wasconductedonaweeklybasis.

19

Figure7.TNconcentrationsintheCaloosahatcheeFAVTsysteminflowandoutflowstreams,for the POR 9/15/14 (initiation of system discharge) through 6/30/15.Monitoring wasconductedonaweeklybasis.

Figure 8.Nitrate+nitrite (NOx) concentrations in the Caloosahatchee FAVT system inflowandoutflowstreams,forthePOR9/15/14(initiationofsystemdischarge)through6/30/15.Monitoringwasconductedonaweeklybasis.

20

Figure9.Ammonia‐NconcentrationsintheCaloosahatcheeFAVTsysteminflowandoutflowstreams,forthePOR9/15/14(initiationofsystemdischarge)through6/30/15.Monitoringwasconductedonaweeklybasis.

Figure10.AlkalinityintheCaloosahatcheeFAVTsysteminflowandoutflowstreams,forthePOR9/15/14(initiationofsystemdischarge)through6/30/15.Monitoringwasconductedonaweeklybasis.

21

Figure11.pH intheCaloosahatcheeFAVTsystem inflowandoutflowstreams, forthePOR9/15/14(initiationofsystemdischarge)through6/30/15.Monitoringwasconductedonaweeklybasis.

TPandpHmonitoringatcellinflowsandoutflows

Water chemistry monitoring at the inflow and outflow of Cells 1 – 3 during November

through June revealed somewhat different temporal trends in TP concentrations among

cells.TPconcentrationintheCell1outflowwassimilarto,orslightlylowerthan,TPinthe

Cell1inflow(systeminflow)duringmuchoftheperiodfromNovembertomid‐February

(Figure12).During the remainderof themonitoringperiod,Cell 1outflowTP showeda

slightoveralldecrease,evenas inflowTPtendedto increase,suggestiveofanincreasein

plantuptakeofPduringthe2015growingseason.ThelowestTPconcentrationsintheCell

1 outflow stream were measured at the end of the reporting period during June 2015,

whenconcentrationsaveraged21µg/Landrangedfrom17to27µg/L.

Cell 2 outflow TP concentration decreased as Cell 2 inflow (same as Cell 1 outflow) TP

concentrationtrendeddownward,withlowerTPlevelsmeasuredintheoutflowduringthe

majorityofthemonitoringperiod(Figure13)reflectingadditionalPremovalinCell2.As

observedfortheCell1outflow,thelowestTPconcentrationsintheCell2outflowoccurred

duringthelatterpartofthemonitoringperiod,inMayandJune.Duringthosemonths,Cell

2outflowTPaveraged14µg/Landrangedfrom12to18µg/L.

22

In contrast to Cells 1 and 2, TP concentrations in the Cell 3 outflow (system outflow)

showedno overall trendduring theNovember – Juneperiod, as indicated earlier in this

report,despitethedecreasingtrendinTPconcentrationintheCell2outflow/Cell3inflow

(Figure14).Thiscouldbeduetoanumberoffactors,includingdiffusivefluxofsoilPtothe

overlying water, enhanced by decreasing Cell 2 outflow concentrations, and a limited

capacityforPremovalviaplantuptakeduringestablishmentofrobustSAVcommunitiesin

Cell3.

Monitoringofcell inflowsandoutflowsalsoshowsaminimalchange inpHacrossCell1

(from inflow to outflow), although during June the Cell 1 outflow pH decreased to

approximately0.3unitslowerthaninflowpH(Figure12).Conversely,pHincreasedacross

Cell 2, especially during the 2015 growing season, while both inflow and outflow pH

trendeddownwardovertime(Figure13).AfurtherincreaseinpHwasobservedbetween

theinflowandoutflowofSAV‐dominatedCell3throughoutmostofthemonitoringperiod,

contributing to the overall net increase in pH between the system inflow and outflow

(Figure14).UnlikeCells1and2,theCell3outflowpHdidnotexhibitadetectabletemporal

trendduringtheNovember‐Junemonitoringperiod.

Figure15summarizestheoverall lineartrend inTPconcentrationalongthesystemflow

path during the November 2014 – June 2015 period, for which inflow‐outflow TP was

monitoredsimultaneouslyforCells1,2and3.ThemeansysteminflowTPconcentrationof

65µg/Lduringthatperioddecreasedtoameanvalueof38µg/LattheCell1outflowand

furtherdecreasedto27µg/LattheCell2outflow.Thesimultaneousdecreaseovertimein

Cell 2 outflow TP concentration and lack of change in Cell 3 outflow TP concentration

(Figure 14) is reflected in Figure 15 as a slight increase in the overallmean outflowTP

concentration (29 µg/L) as compared tomeanCell 2 outflowTP. Standard deviations of

meanTPconcentrationsatthecellinflowandoutflowpointsreflectasubstantialdecrease

intemporalvariabilityinTPconcentrationsalongthesystemflowpath,andareindicative

ofsubstantialattenuationwithinthesystemofhighlyfluctuatinginflowTPconcentrations

observedduringthemonitoringperiod.

23

Changes in pH across sequential treatment cells are summarized in Figure 16.Mean pH

valuesfortheNovember‐JuneperiodindicatethesmalldecreaseinpHobservedbetween

thesysteminflowandCell1outflow,andsubsequentincreasesinpHacrossCells2and3.

ThemeanpHof7.34at thesysteminflowdecreasedslightly toameanpHof7.31atthe

Cell1outflow,whilethemeanpHvaluesfortheCell2andCell3outflowswere7.53and

7.74,respectively.

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Figure12.SurfacewaterTPconcentrationandpHattheinflowandoutflowofCell1oftheCaloosahatcheeFAVTsystem.MonitoringwasconductedonaweeklybasisfromNovember2014throughJune2015.

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26


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Figure 15. Mean surface water TP concentration (±1 standard deviation) at the systeminflow (=Cell1 inflow),Cell1outflow (=Cell2 inflow),Cell2outflow (=Cell3 inflow),andsystemoutflow(=Cell3outflow)oftheCaloosahatcheeFAVTsystem.Valueswerecalculatedfromdatacollectedduring34weeklymonitoringeventsfromNovember2014throughJune2015.

Figure 16.Mean surfacewater pH (±1 standard deviation) at the system inflow (=Cell 1inflow),Cell1outflow (=Cell2 inflow),Cell2outflow(=Cell3 inflow),andsystemoutflow(=Cell 3 outflow) of the Caloosahatchee FAVT system. Valueswere calculated from datacollectedduring34weeklymonitoringeventsfromNovember2014throughJune2015.

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InternalwaterchemistrymonitoringofCells1and2

ResultsofinternalmonitoringofTPandSRPindicatedthatPremovalwithinthewetland

followed a predictable spatial pattern, with gradual reductions in TP concentrations

occurringinCell1asdistanceincreasedfromtheinflowthroughthecell.TPlevelsinthe

backtwo‐thirdsofCell2wereextremelylow,at15µg/Lorless(Figure17).Theobserved

spatial trends inTP suggest thatmuchof thepumped inflowwaterpreferentiallypasses

alongtheeasternsideofCell1.Thebioavailablephosphorous(SRP)results,manyofwhich

werebelow thedetection limit of2µg/L, also support thishypothesis,withhighest SRP

levels observed along the eastern portion of the flow path (Figure 17). Plant cover and

densityalsomayaffecttheobservedspatialpatternsinPremoval,andthiswillbeatopic

offutureassessmentatthisfacility.

29

Figure17.InterpolatedspatialTPprofilesinCells1and2(top),andindividualdatapointsforSRP(notinterpolated)forCells1and2(bottom),fortheinternalwaterqualitymonitoringeventinJun2015.NotethatmostSRPvaluesinCells1and2werebelowthedetectionlimit,sonointerpolationofthesedatawasperformed.

30

FloatingandSubmergedAquaticVegetationSurveys

Visualassessmentofspeciationandarealcoverage(i.e.,relativeabundance)ofFAV(Cells1

and 2) and SAV (Cell 3)was performed on a routine basis at stations located on a pre‐

determinedgridpattern acrossCells 1 (21 stations), 2 (33 stations) and3 (53 stations).

These surveys were conducted monthly from October 2014 through June 2015. Survey

dates were 10/28/14, 11/30/14, 12/30/14, 1/30/15, 2/24/15, 3/30/15, 4/30/15,

5/27/15,and6/23/15.

DuringturbidwaterconditionsorwhenSAVwasnotvisibleinthewatercolumn,theSAV

assessment in Cell 3 was performed using a systematic collection method, whereby a

garden rake was dragged three times along the bottom (~1 m distance) to collect the

vegetation. Note that this rake method was not used if dense SAV was present. The

coverageofeachspecieswasscoredbasedonthefive‐pointscalebelow.ForSAV,eachof

thesecoveragecategoriesincludedvegetationobservedwithinthewatercolumnaswellas

anyvegetationcollectedwiththerake.

Vegetationcoverage(relativeabundance)categorieswerereportedasfollows:

None Sparse:0–10percent ModeratelyDense:10–40percent Dense:10–80percent Verydense:>80percent

Resultsof theFAVsurveysreflectamonthly increase inmoderately‐dense tovery‐dense

(hereafterreferredtoas“dense”)coverageofwaterhyacinth(Figure18)inCells1and2

between late October 2014 andmid‐February 2015 (Figure 19). In Cell 1, the extent of

“dense” hyacinth coverage increased from 56 to 95 percent of stations during this time

period, then remained relatively constant, at ca. 90 percent of stations, during the

subsequent months, through June 2015. During the same time periods, the extent of

“dense”hyacinthcoverage inCell2 increasedfrom33percent to81percent, thenvaried

between67and93percent.Duringallbutonemonitoringevent“dense”hyacinthcoverage

wasgreaterinCell1thaninCell2,presumablyduetothehigherconcentrationsofplant‐

available nutrients in Cell 1. Hyacinthwas present at all stations in Cell 1 during every

31

monitoring event, while in Cell 2 hyacinth was found at all stations during all but two

events(Figure20).

CoverageofPistiastratiotes(waterlettuce)wasconsistentlylowerthanhyacinthcoverage,

in both cells (Figure 21). In Cell 1, “dense” coverage ofPistiawas found at less than 30

percentofstationsduring thecourseof themonitoringperiod(Figure19).Theextentof

“dense”coveragedecreased to less than10percentduringMarch through June inCell1.

Initial “dense”coverageofPistiawas lower inCell2 than inCell1,but theextentof this

coverage slowly increased to 19 percent by the end of March. During the subsequent

monitoringevents(April–June),“dense”Pistiacoveragedecreasedtolessthan15percent.

PresenceofPistia,atalldensities,wasinitiallyhighinCell1(94percentofstations),but

thefrequencyofoccurrencedecreasedsteadilythroughMarchto24percent(Figure20).

PistiawasmorefrequentlyobservedinCell2thaninCell1,primarilyatverylowdensities,

during all but the first monitoring event in late October, when it was found at only 20

percentof stations.During the last survey in themonitoringperiod (June23),Pistiawas

presentat19percentofstationsinCell1and43percentofstationsinCell2.

The spatial distributionsof hyacinth andPistia are shown forbi‐monthly intervals, from

October2014throughJune2015,inFigure22.Thetimeseriesofcoveragemapsatthetop

ofthefigureshowthespreadofmoderatetoverydensehyacinthtowardtheCell1inflow

and Cell 2 outflow during theOctober – April period. A slight decrease in coveragewas

observed in the western portion of Cell 2 during June, likely due to wind‐induced

movement of the plants. Relatively dense stands of Pistia filled in considerably from

OctoberthroughDecembertowardtheCell2inflowandoutflowregions(bottomofFigure

22), and during subsequent months the coverage varied in location and total extent. In

contrast,PistiacoveragetendedtorecedetowardthesouthinCell1,downstreamfromthe

systeminflow.

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Figure18.VerydensematofEichhorniacrassipes(waterhyacinth)andPistiastratiotes(waterlettuce)inCell1

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Cell 1:

Cell 2:

Figure19.Time‐seriesforFAVspecieswithinCells1and2depictingthepercentofstationsthatwasmoderatelydenseorgreaterforeachspecies.

0102030405060708090100

10/28/14

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6/23/15% of stations moderately

den

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E. crassipes P. stratiotes

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34

Cell 1:

Cell 2:

Figure20.Time‐seriesforFAVspecieswithinCells1and2depictingthepercentofstationsthateachspeciespresent.

0102030405060708090100

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35

Figure21.MixedspeciesmatwithEichhorniacrassipes(waterhyacinth)andPistiastratiotes(waterlettuce)inCell1.

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Figure22.RelativecoveroftheFAVspeciesEichhorniacrassipesandPistiastratiotesinCells1and2oftheCaloosahatcheewetlandduringOctoberandDecember2014andFebruary,April,andJune2015.Theblackdotsrepresenttheobservationlocations,andthesixsemi‐quantitativedensitycategoriesareshowninthelegend.

37

SAV survey results for Cell 3 revealed that, out of eight species reported during the

monitoringperiod, only twospecies,Najas (Figure23) andUtricularia (Figure24),were

commonly found (greater than 50 percent of stations) at amoderate or greater density,

whileathirdspecies,Hydrilla,increaseddramaticallyincoveragebytheendoftheperiod

after being passively introduced (not inoculated) (Figure 25). Coverage of “dense”

Utriculariavariedbetween42and70percent,withnoapparenttemporaltrend,duringthe

period,whilecoverageof“dense”Najasshowedanoverallincreasethroughouttheperiod,

from9to70percent(Figure26).“Dense”Hydrilla occurredatonlyafewstationsduring

thefirstsixmonitoringevents,butsteadilyincreasedinextentthroughJuneto≥30percent

ofstations.“Dense”BacopawasobservedwithinCell3duringallmonitoringevents,butat

less than 15 percent of stations, on a consistent basis. Similarly, “dense” Chara was

observedduringallsurveys,butatonlyafewstations.Ceratophyllum,Ludwigiarepensand

Potamogetonwerefoundathigherdensitiesatonlyafewstationsandonlyduringasubset

ofmonitoringevents.

UtriculariaandNajas(duringlatersurveys)werebyfarthemostcommonSAVspeciesin

Cell 3, occurring at the majority of monitoring stations (Figure 27). Bacopa was

consistentlypresent inCell3duringallmonitoringevents,withamore limitedextentof

about10to30percentofstations.Charawasalsopresentduringallevents,butataneven

lowerspatialextentoflessthan10percent.OverallpresenceofLudwigiadecreased,while

CeratophyllumandPotamogetonwererelativelyscarcethroughoutthemonitoringperiod.

Incontrast,theoccurrenceofHydrillawasextremelylimitedduringOctober‐February,the

extentof coverage rapidly increasedduring theperiodApril‐June2015, to45percentof

stations.

The spatial extent of the most prevalent SAV species, Najas, Utricularia and Hydrilla,

exhibiteduniquespatialpatternsduring themonitoringperiod(Figure28).Forexample,

NajastendedtocolonizetheinflowandoutflowregionsofCell3overtime,whileHydrilla

proliferatedprimarilyinthemid‐regionofCell3,towardtheendofthemonitoringperiod.

UtriculariamaintainedarelativelyconsistentdensityacrossCell3forthedurationofthe

monitoring period, although the coverage became somewhat “patchy” near the Cell 3

38

inflowandoutflowregions.Changes indensityandspeciescompositionduring theearly

stages of system operation will likely continue during the short term as water and soil

chemistry across the system stabilize. In addition, inter‐specific competition will play a

largeroleintheeventualdistributionofSAVspeciesinCell3.

Continued monitoring of both SAV and FAV will be performed in FY 2016, in order to

enhancesystemoperationsandmanagementpractices,andtofacilitateourunderstanding

ofspatialandtemporalpatternsinTPremovalperformance.

Figure23.Najasguadalupensis(southernnaiad)growingneartheoutflowofCell3.

39

Figure24.MixedSAVassemblagecontainingUtriculariasp.(bladderwort)andotherspeciesinCell3.

Figure25.Hydrillaverticillata,aninvasiveSAVspecies,attheCell2culvert.

40

Figure26.Time‐seriesforSAVspecieswithinCell3depictingthepercentofstationsthatstationsthatwasmoderatelydenseorgreaterforeachspecies.

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Figure27.Time‐seriesforSAVspecieswithinCell3depictingthepercentofstationsthateachspeciesispresent.

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Figure28.RelativecoverofNajasguadalupensis,Utriculariaspp.,andHydrillaverticillatainCell3oftheCaloosahatcheewetlandduringOctoberandDecember2014,andFebruary,April,andJune2015.Theblackdotsrepresenttheobservationlocations,andthesixsemi‐quantitativedensitycategoriesareshowninthelegend.

Documents

Task 20 Deliverable: Final Report 1 · Executive summary Water & Soil Solutions, LLC (WSSLLC) has deployed an approximately 523‐acre Floating Aquatic Vegetative Tilling (FAVT) wetland