Monitoring cruise at the New London disposal site, 1992-1998 : Volume II, Seawolf Mound

272 Pages·2001·8.7 MB·English

by  United States. Army. Corps of Engineers. New England District

Monitoring Cruise at the New London Disposal Site 1992-1998
Volume
II
Seawolf Mound
Disposal Area
Monitoring System
DAMOS
DA^«Mi_ OS
DISPOSALAREAMONITORINGSYSTEM
Contribution 132
December 2001
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Uniy Corps
no 132-
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England District

REPORT DOCUMENTATION PAGE formapproved
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1.AGENCYUSEONLY (LEAVEBLANK) 2.REPORTDATE 3.REPORTTYPE ANDDATESCOVERED
December2001 FINALREPORT
4.TITLEANDSUBTITLE 5.FUNDINGNUMBERS
MonitoringCruiseattheNewLondonDisposalSite,1992-1998.VolumeII,SeawolfMound
6.AUTHOR(S
ScienceApplicationsInternational
PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES) 8.PERFORMING
ScienceApplicationsInternationalCorporation ORGANIZATIONREPORT
221ThirdStreet NUMBER
Newport,RI 02840 SAICNo.525
SPONSORING/MONITORINGAGENCYNAME(S)ANDADDRESS(ES) 10.SPONSORING/MONITORING
USArmyCorpsofEngineers-NewEnglandDivision AGENCYREPORTNUMBER
696VirginiaRoad
Concord,MA01742-2751 DAMOSContributionNumber132
11.SUPPLEMENTARYNOTES
AvailablefromDAMOSProgramManager,RegulatoryDivision
USACE-NAE,696VirginiaRoad,Concord,MA01742-2751
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Approvedforpublicrelease;distributionunlimited
13.ABSTRACT MonitoringsurveysoftheU.S.NavySeawolfMoundwithintheNewLondonDisposalSite(NLDS)wereconductedin
September1997andJuly1998. Fieldoperationsincludeddatacollectionofoneormoreofthefollowing:precisionbathymetricsurveys,Remote
EcologicalMonitoringoftheSeafloor(REMOTS),sediment-profilesurveys,grabsamplingofbenthicinvertebrates,andsedimentcoring. This
reportsummarizesthedisposalandmonitoringactivitiesattheSeawolfDisposalMoundfrom1995-1998. Acompanionreport,VolumeI,covers
monitoringconductedatothermoundsinthesitefrom1992-1998.
TheNLDShasbeenusedforon-goingdisposalthroughoutthe1990's,includingunconfineddisposalofsuitablesediments,andcappeddisposal
ofunsuitablesediments. During1995-1996,theNLDSreceivedatotalbargevolumeof877,500m3ofdredgedmaterialgeneratedfromthree
separateprojects(Seawolf,VenetianHarborandMysticRiver)intheeasternLongIslandSoundregion. Disposalresultedincreationofone
disposalmound,theU.S.NavySeawolfMound,consistingofunsuitabledredgedmaterial(ThamesRiverchannelandberthingareas,and
MysticRiver)andsuitablecapmaterial(ThamesRiverchannel,VenetianHarborandMysticRiver).
Bathymetricsurveys,REMOTSdataandsedimentcoredataconfirmedthattheSeawolfMoundwascappedwithatleast50cmofsuitable
dredgedmaterial. TheSeawolfMoundformedaflat,nearlycirculardepositwithadiameterofapproximately600m.Afteraninitialperiodof
consolidation(9monthsto1year),themoundsettledtoanaverageheightof2mwithasmallovalapexof3m. Acrossthesurfaceofthis
mound,alayer(0.5-3m)ofsuitablematerialformedacapconsistingofsandysedimentsandgrayglacialclaysfromimprovementdredgingin
theThamesRiverchannel.Basedonvisualanalysisandbenthicsampling,recolonizationofthefreshdredgedmaterialbymarineinvertebrates
proceededasexpectedwithbiologicalcharacteristicssimilartoNLDSreferenceareas.
Physicalandchemicalanalysisofsedimentcorescollectedin1997and1998confirmedthatthetop50cmofthemoundwaschemicallyconsistent
withthesuitablecappingmaterial. Therewasnoevidenceofmigrationorreleaseofcontaminantsfromlayersbeneaththecap. Onlylongcores
(>2m)clearlypenetratedbeneaththecapintoeitherambientsedimentsorunsuitablematerial. Theseresultsareconsistentwiththeconclusion
thatthecapisastable,thicklayerthathaseffectivelyisolatedtheunsuitablesedimentsfromtheenvironmentofLongIslandSound.
14.SUBJECTTERMSDAMOS,Seawolf,SedimentCores,Capping,BenthicRecolonization 15.NUMBEROFTEXTPAGES: 146
16.PRICECODE
17.SECURITYCLASSIFICATIONOF 18.SECURITYCLASSIFICATION 19.SECURITYCLASSIFICATION 20.LIMITATIONOF
REPORT Unclassified OFTHISPAGE OFABSTRACT ABSTRACT

MONITORING CRUISE
AT THE NEWLONDONDISPOSAL SITE 1992-1998
VolumeII
SeawolfMound
CONTRIBUTION#132
December2001
ReportNo.
SAIC-525
Submittedto:
RegulatoryDivision
NewEnglandDistrict
U.S. ArmyCorpsofEngineers
696VirginiaRoad
MA
Concord, 01742-2751
m
'- r-=l Submittedby:
i zr ScienceApplicationsInternationalCorporation
Admiral'sGate
221 ThirdStreet
Newport,RI02840
[phone]
o E3
JSArmy'Corps
ofEngineers®
(
NewEngand District

TABLEOFCONTENTS
Page
LISTOFTABLES v
LISTOFFIGURES vii
EXECUTIVE SUMMARY x
INTRODUCTION
1.0 1
1.1 Background 1
1.2 SeawolfDisposalMound 6
1.2.1 U.S. NavySeawolfDisposalActivity 6
1.3 MonitoringActivity 9
1.3.1 September 1997Monitoring Survey 9
1.3.2 July 1998 Monitoring Survey 10
METHODS
2.0 11
2.1 BathymetryandNavigation 11
2.1.1 1997 and 1998 SurveyActivity 11
2.1.2 Bathymetric DataCollection 13
2.1.3 Bathymetric DataProcessing 13
2.2 SedimentProfilePhotography 15
2.2.1 SeawolfDisposalMound 20
2.2.2 NLDS ReferenceAreas 24
2.3 Benthic CommunitySampling 24
2.3.1 SedimentGrabSampling 24
2.3.2 LaboratoryAnalysis 27
2.4 SedimentCores 27
2.4.1 FieldCollections 28
2.4.2 SedimentSampling 32
2.4.3 LaboratoryAnalysisMethods 32
2.4.4 QualityAssurance/QualityControl 36
3.0 RESULTS 42
3.1 SeawolfMound 42
3.1.1 Bathymetry 42
3.1.2 REMOTS® Sediment-ProfilePhotography 57
3.1.3 BenthicCommunityAnalysis 69
3.1.4 SedimentCoring 76
3.2 NLDS ReferenceAreas 102
4.0 DISCUSSION 105
4.1 Historical DisposalandBiologicalResponseattheNLDS 105
4.2 SeawolfDisposalMound 107
4.2.1 TopographicChanges ofthe SeawolfMound 108
4.2.2 Benthic CommunityRecolonization 109
4.2.3 PotentialResuspensionfromthe SeawolfMound 122
4.2.4 SedimentChemistryofthe SeawolfMound 130
5.0 CONCLUSIONS AND RECOMMENDATIONS 138
5.1 Overview ofNLDS Monitoring 138
5.2 U.S. NavySeawolfMound 139
5.3 Recommendations 142
6.0 REFERENCES 143
APPENDICES
INDEX
LISTOFTABLES
Page
Table 1-1. TimeseriesofBathymetric Surveys ofthe SeawolfMound 9
Table2-1. SummaryofSurveyactivityperformedoverthe SeawolfDisposal
Moundin 1997 and 1998 12
Table2-2. Grain Size Scales forSediments 18
Table2-3. CalculationofREMOTS®OrganismSedimentIndexValue 21
Table2-4. SeawolfDisposalMoundandNLDSReferenceAreas 1997 and 1998
REMOTS®Sediment-ProfilePhotographyStations 23
Table2-5. SeawolfDisposalMound 1997SedimentGrabSamples 27
Table2-6. SeawolfDisposalMound 1997 SedimentCores 30
Table2-7. SeawolfDisposalMound 1998 SedimentCores ...31
Table2-8. MethodsofPhysicalandChemicalAnalysesforNLDS SeawolfCore
Subsamples 33
Table3-1. REMOTS®DataCollectedattheSeawolfDisposalMoundinSeptember 1997
andJuly 1998.... 59
Table3-2. REMOTS®DataCollectedattheNLDS ReferenceAreas inSeptember 1997
andJuly 1998 60
Table3-3. BenthicCommunityParametersattheNLDS SeawolfDisposalMound 74
Table3-4. ResultsofPhysicalAnalysisofSamplesCollectedfromtheSeawolfCores,
September 1997 79
Table3-5. TraceMetalConcentrations inSamples CollectedfromtheSeawolfCores,
September 1997 80
Table3-6. 1997ResultsofTraceMetalsNormalizedtotheFine-GrainedFraction
inSamplesCollectedfromtheSeawolfCores 82
Table3-7. PAHConcentrationsinSamplesCollectedfromtheShortSeawolfCores
(0-0.5 m), September 1997 86
LISTOFTABLES (continued)
Page
Table 3-8. PAHConcentrations inSamplesCollectedfromtheLongSeawolfCores,
September 1997 87
Table3-9. ResultsofPhysicalAnalyses ofSamplesCollectedfromtheSeawolfMound
Cores,July 1998 92
Table3-10. TraceMetalConcentrations inSamplesCollectedfromtheSeawolfMound
Cores,July 1998 95
Table3-11. ResultsofTraceMetalsNormalizedtotheFine-GrainedFractionin Samples
CollectedfromtheSeawolfMoundCores,July 1998 96
Table3-12. ResultsofPAHAnalyses ofSamplesCollectedfromtheShortSeawolfMound
Cores (0-0.5 m),July 1998 98
Table3-13. ResultsofPAHAnalyses ofSamplesCollectedfromtheLongSeawolfMound
Cores,July 1998 99
Table4-1. Infaunalsuccessionalstageclassificationsforselectedtaxacollectedacross
theSeawolfMound (descriptionsforpolychaetefamiliesarebasedon
FauchaldandJumars, 1979) Ill