SiltRemovalTeam5-YearSummaryReport

TowerLakesOurmostimportantAsset

�  68AcresincludingNorthLake�  4milesofshoreline�  2majorinletstoMainLake�  3existingsilttraps�  Vastmajorityofwaterenters

fromstormwaterrun-off�  Acrosslawns�  Stormwaterdrainpipes

LakeCommi*eeGoals&Impacts

Rain=Watershed&RoadRun-off

Sun

Fishery&NaturePreserve

Boating

Nutrients,Phosphates&Trash

Swimming&WaterSports

InvasiveWEEDS ALGAES

WATERQUALITY

DEPTHSILTUSE

IMPA

CT

LakeManagementChallengesEutrophica:on

Eutrophication:Theprocessbywhichabodyofwaterbecomesenrichedwithdissolvednutrients(suchasphosphates)thatstimulatethegrowthofaquaticplantlifeusuallyresultinginthedepletionofdissolvedoxygen.Lakesthatcannotcontrolthisprocesswillendupas“dead”lakes,andeventuallybogsorswamps.

LakeManagementChallenges

Nutrients•  FOODforplants•  PhosphatesandNitrogen

naturallyoraddedviarunoff•  ExistingSiltfromlakecreation•  Siltenteringthelakefrominlets

andstormwaterrunoff•  Siltcreatedbyorganic

decomposition•  Leaves•  Sticks•  Deadaquaticplants

AquaticPlants•  GOODforfish

•  ProvideOxygen•  Createhabitat

•  Fedbynutrients•  Difficultforswimmingand

boating•  Weexecuteaplantomanage

speciesandcoverage•  EliminateorMitigateNuisance

Weeds

WeHaveAHistoryasCARETAKERSofthisLake!1966-1968

SiltRemovalProject2012-2016WhyRemoveTheSilt?

•  LargebuildupofNutrient-RichSedimentoverseveraldecades.

•  EngagedinRegularCycleof:•  (1)ObservePlantorAlgaeGrowth•  (2)ChemicallyKilltheGrowth•  (3)ObserveRe-GrowthofPlants&Algae

•  WantedtoBreaktheCycle.

SiltRemovalProject2012-2016Op:onsConsidered

•  TraditionalDredging(Scoop&Haul)

•  Expensive•  DraintheLaketodoproperly•  Limited(ifany)useoftheLakeduringtheTraditionalDredgingprocess

•  HydraulicDredging(SlurryVacuumOperation)

•  Lessexpensive•  LeastdisruptiveorvisibletoHomeowners•  Considered“Barge”vs.“Diver”(UsedBoth)

SiltRemovalProject2012-2016HopedForResult

•  Removelargevolumesofmuck•  Significantlyreducenutrientsourcethatfuelsundesirableplantandalgaegrowth

•  CreateimprovedLakeconditions•  Appearance•  Biosystem(Health)•  EnhancedRecreationalUse

•  Boating•  Fishing•  Swimming

•  Donewithout“chemicalizing”theLake.

SiltRemovalProject2012-2016

•  TLIAmembersapprovedin2011•  $250/yearassessmentfor5years•  Siltremovalandrestorationonly•  Projectedthreeareas•  Originalsilttraplocations

•  Davlin’sandChannel•  RobertsRoad•  SoutheastMainLake

•  78%MembershipApproval

SiltRemovalProject2012-2016NecessaryPre-Work(#1)

•  SiltChemicalAnalysis(ConfirmnotHazardousMaterial)

•  SiltGrowthTests(ConfirmGrassorPlantGrowthPossible)

•  HomeownersAssociationMarketing&Buy-In•  DevelopmentofaComprehensive5-YearPlan•  IndependentSiltSurveys(ConfirmAmountandLocationofSilt)

•  ResearchSiltCollectionBagLocations(Pros/Cons)•  ContractingwithEnvironmentalConsultant

SiltRemovalProject2012-2016NecessaryPre-Work(#2)

•  DevelopmentofHydraulicDredgingContractorOptions•  SomeContractors“toobig”;Some“toosmall”;•  Onlyafewwere“justright”

•  DevelopmentofRequestforProposals•  ReviewofContractorBids•  ContractorSelection•  Permits!(USArmyCorpofEngineers;ILEPA;LCSWM)

SiltProjectPhaseI(July–October2013)

Davlin’sPondandChannel

SiltProjectPhaseI(2013)–SUMMARY

•  Removed9,000CubicYardsofwetsilt

•  900CubicYardsofdriedsilt

•  Deepenedsomeareas2feetto4feetdeeper

•  Re-established#1SiltTrap

SiltProjectPhaseIIRobert’sRoadSouth(2014-15)

•  Fallof2014andSummer2015

•  Removed3,500CubicYardsofwetsuspendedsilt

•  350CubicYardsofdriedsilt•  UtilizedcapacityatNorthLakeEntrance

•  Re-established#3SiltTrap(1994)

Lathan’sLanding–WetlandRestora:on

•  Collaborationw/VOTLandLakeCountyStormwaterMgt

•  $12,000LCWMBgrant(Dec2014)

•  $21,750VOTLmatch•  Remediatedwetland“swamp”•  Fixedoldcatchbasin&replaceddrainagepiping

•  SiltatNLentrancemovedandseeded

•  Depressionfilledandre-landscaped

SiltfillfromPhaseIandII

Lathan’sLanding–WetlandRestoration

Endresultisanawesomeboatlaunch

Largercatchbasin

SiltProjectPhaseIII(July–October2016)

KelseyWoods•  JulytoSeptember2016•  Removed9,000CubicYardsofwetsilt

•  900CubicYardsofdriedsilt

•  Deepenedsomeareas2feetto6feetdeeper

•  Re-established#2SiltTrap•  Mostefficientprojecttodate

•  Kelseysitehascapacityandpermittingforfutureprojects

SiltRemovalSummary�  Removedapproximately:

�  25,000WetSuspendedcubicyardsofsilt�  2,500Drycubicyardsofsilt

�  DeepenedallthreepreviousSilttraps�  Developedextensivelearningviacollaborationwithlocalagenciesand

neighboringlakes�  Becamemoreefficientovertime�  Provided:

�  Exampletoothercommunities�  Deliveredmultiple“howto”presentationsasrequested

�  Successfullyimplementedfirststepsto“longtermmaintenance”ofourlakes

10CubicYardsIsaTruckload!

246DryTruckloadswereremediatedonsitevs.costofover$60,000tohaulaway.

Consul:ng,$(43,140.64),

-10%

Permieng,$(8,370.00),-2%

Lathan'sLanding,$(29,177.27),-7%

Remedia:on,$(8,083.02),-2%

BAGCost,$(43,847.00),-10%

SiltPumping,$(283,150.00),-65%

SetUp,$(19,941.32),-6%

TotalExpenditures$435,709.25

Financials

Financials•  ImportantMetrics:(approximations)

•  ActualSiltRemoval(pumping)was~65%ofProjectcost•  TotalSiltRemoval(setup,bags,pumping)was~80%ofcost•  Therefore,Non-SiltRemovalcostswere~20%ofTotalProjectcosts

•  IncludedcostsofConsultant(s),Permits,Remediation•  Smallerprojectswillhaveconsiderablyhigher“other”costs•  ThescaleofourProject(3Phases)drovedowntheNon-SiltRemovalCosts

from~33%(Phase1only)to~20forPhases1–3•  DriedSiltrelocationand/ordisposalcostscouldbesubstantial

•  (Thesiltwasusedon-site,hencenodisposalcosts)

•  VERY,VERYROUGHESTIMATES:(Useatyourownrisk!)•  Totalcostwas~$175perdried,compressedcubicyardofsiltremoved•  Totalcostwas~$17perwet,dispersedcubicyardoflakesedimentremoved

SiltRemovalChallenges&LessonsLearned•  CosttoHomeowner’sAssociation•  StakeholderSupport(Criticaltohave“Buy-In”fromallrelevantparties)Terrificsupporteventhough~75%ofTLIAHomeownersdonotownshorelineproperty.•  Permits(timing)arecrucialtoProjectschedule•  MusthavegoodrapportwithSiltRemovalContractor

•  However,mustdiligentlymonitorContractorandkeepontaskthroughoutProject

•  SiltDrydownTime-Longtimetodryout;Unsightly!•  SiltDisposal-Unabletosell.UltimatelyusedallthesiltwithinTowerLakes.Thisisa

critical(andpossiblyunder-appreciated)issue.Disposalcostscouldbesubstantial.

•  Mustminimize“extraneous”costssofaraspracticalDifficult,butmaximizingSiltRemoval(Pumptime)iscritical.

•  Difficulttotell(withcertainty)oftheoverallsuccessoftheprocess-Underwater!Initiallyappearstohave“worked”.

LakeMaintenanceRequest–BestManagementPrac:ces(BMPs)

•  WeedHarvesting•  AlumTreatments•  Aeration•  WaterElevators•  WaterMovers•  FloatingIslands

Needtoresearchandevaluatethese

potentiallakemanagementsolutions

LakeMaintenanceRequest

•  Stillneedtoremovesiltincriticalremainingareas

•  Fundsfortwomoreremovalprojects

•  KelseyRoadsiteisavailableandpermittedformoresilt

•  AlsoneedtoresearchandexperimentwithotherlakemanagementBMPs

•  AskingfornewLakeSpecialAssessment@$200/HHfor5years

10CubicYardsDryvs.Wet

TheWetSuspendedVolumeintheLakewas10xthedry246Truckloads

SoinEffect2,460TruckloadsofSiltbyVolumehasbeenRemoved!

20,000cubicyardsunder12to15surfaceacresofthelake