Monitoring cruise at the Morris Cove borrow pit

60 Pages·2001·1.7 MB·English

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

Monitoring Cruise at the Morris Cove Borrow Pit
Disposal Area
Monitoring System
DAIVIOS
DATA
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DISPOSALAREAMONaORINSSYSTEM
Contribution 129
June 2001
US Army Corps
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REPORT DOCUMENTATION PAGE formapproved
OMB No. 0704-0188
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searchingexistingdatasources,gatheringandmeasuringthedataneededandcorrectingandreviewingthecollectionofinformation. Sendcomments
regardingthisburdenestimateoranyotheraspectofthiscollectionofinformationincludingsuggestionsforreducingthisburdentoWashington
HeadquartersServices,DirectorateforinformationObservationsandRecords, 1215JeffersonDavisHighway, Suite 1204,Arlington VA22202-4302
andtotheOfficeofManagement andSupport, PaperworkReduction Project(0704-0188),Washington,D.C.20503.
1.AGENCYUSEONLY (LEAVEBLANK) 2.REJuPnOeR20T01DATE 3.REPORTTFYIPNEALARNEDPODRATTESCOVERED
4.TITLEANDSUBTITLE 5.FUNDINGNUMBERS
MonitoringCruiseattheMorrisCoveBorrowPit
6.AUTHOR(S)
ScienceApplicationsInternationalCorporation
7.PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES) 8O.RPGEARNFIOZRAMTIINOGN REPORT
ScienceApplicationsInternationalCorporation
NUMBER
221 ThirdStreet
Newport,Rl02840 SAICNo.520
9.SPONSORUISNAGr/mMyONCoIrTpOsRoIfNEGngAiGneEeNrCs-YNeNwAMEEn(glSa)nAdNDiDstAriDcDtRESS(ES) A10G.ESNPOCNYSROERPIONRG/TMNOUNMIBTOERRING
696VirginiaRd DAMOSContributionNumber129
Concord,MA 01742-2751
SUPPLEMENTARYNOTES
11.
AvailablefromDAMOSProgramManager,RegulatoryBranch
USACE-NAE,696VirginiaRd,Concord,MA01742-2751
12a.DISTRIBUTION/AVAILABILITYSTATEMENT 12b.DISTRIBUTIONCODE
Approvedforpublicrelease;distributionunlimited
13.ABSTRACT
DuringJanuaryandMay2000,anestimatedtotalof14,200m'ofsedimentdredgedfromtheU.S.CoastGuardBaseinNewHaven,CTwasplacedinasmall,man-made
depression(borrowpit)inMorrisCove,locatedinouterNewHavenHarbor. AmonitoringsurveywasconductedovertheMorrisCoveborrowpitinlateSeptember2000
todocumentthedistributionofthedredgedmaterialontheseafloor,verifythestabilityofthesedimentdeposit,andevaluaterecolonizationofthedepositbybenthic
ocorngdaintiisomnss.wTithheinmoannidtoardijancgeinntvtoolvtehdebtoherruoswepoift.RESeMdiOmTenSt®-prsoefdiilmeenitm-apgroefsilaelsiomwaegriengo,btsaidien-esdcaatnasorneafre,resnicneglaer-eabelaomcabtaetdhyampeptrroyx,imaantdeltyow8e0d0vmidweeosttooefvtahleuabtoerbreonwthpiictto
provideacomparisonwithambientseafloorconditions.
Theside-scansonardatashowedacleardifferentiationbetweensoftersedimentswithintheborrowpitandcoarser,morecompactsedimentscompnsingtheouterwallsof
thepit. Multiplebottomfeatureswithincreasedverticalreliefandsurfaceroughnessdetectedwithina50mradiusofthecentraldisposalpointandtotheeastofthispoint
wereattributedtodredgedmaterialdeposition. Boththeside-scansonarandtowedvideodatasuggestedthattheimpactsassociatedwiththedepositionofdredged
materialwerecontainedlargelywithinthesouthernportionoftheMorrisCoveborrowpit. Thecontrolledplacementofsmallbargeloadsofdredgedmatenalhad
facihtatedthecreationofasmall-scalesedimentdepositwithintheconfinesofthepit. TheREMOTS®sediment-profileimagesservedtoconfirmthepresenceofdredged
matenalatstationslocatedwithintheborrowpit. Thedredgedmaterialwasobservedatstationsincloseproximitytothedisposalbuoypositionandextendingout100to
150mfromthiscentraldisposalpoint. Themeasuredthicknessofthedredgedmateriallayertypicallyexceededthepenetrationdepthofthesediment-profilecamera(i.e.,
greaterthanabout10or15cm). Thedredgedmaterialwaspredominantlyfine-grained,consistingofsoft,sandysilt.
Thepresenceofmethanegasbubblesinthesedimentatthreestationswithintheborrowpitsuggestedthatsomeofthedredgedmaterialcontinuestocontainahigh
inventoryoforganicmatter. Fine-grainedsedimentshavingrelativelyhighsurfaceboundaryroughness,shelllagdeposits,andshallowdepthofaerationcharacterized
thereferencearea. Itwashypothesizedthattheshallowreferenceareamayexperienceperiodicphysicaldisturbancefromfishingactivitiesorthescouringactionofwaves
andcurrentsdurmghighwindevents.
Atthetimeofthesurvey(5monthspostdisposal),itappearedthatbenthicrecolonizationofthedredgedmaterialdepositwasprogressingasexpected. Thesediment-
profileimagesshowedthatthebenthicinfaunaincludedprimarilyStageIopportunisticpolychaetes(i.e.,pioneeringtaxa)atthesedimentsurface. Relatively
well-developedredoxdepthswerenotedatmoststations,andadvancedsuccessionalstages(StagesIIand/or111)wereobservedat8ofthe22stationsoccupied. Dueto
theprotectednatureoftheborrowpitandtherecentinputoforganicallyenrichedsediment,overallbenthichabitatqualitywithintheborrowpitwasconsideredtobe
betterthanthatatthenearby,shallowreferencearea.
14.SUBJECTTERMS MorrisCove,NewHavenHarbor,BorrowPit,DredgedMaterial 15.NUMBEROFTEXTPAGES: 38
16.PRICECODE
17.SECURITYCLASSIFICATIONOF 18.SECURITYCLASSIFICATION 19.SECURITYCLASSIFICATION 20.LIMITATIONOF
REPORT Unclassified OFTHISPAGE OFABSTRACT ABSTRACT

MONITORING CRUISE
AT THE MORRIS COVE
BORROW
PIT
CONTRIBUTION #129
June2001
ContractNo.
DACW33-00-D-0001
SAICReportNo. 520
Submittedto:
RegulatoryBranch
NewEnglandDistrict
U.S. ArmyCorpsofEngineers
696VirginiaRoad
MA
Concord, 01742-2751
Submittedby:
ScienceApplicationsInternationalCorporation
Admiral'sGate
221 ThirdStreet
Newport,RI02840
[phone]
USArmyCorps
ofEngineers®
NewEngland District

TABLE OFCONTENTS
Page
LISTOFTABLES iii
LISTOFHGURES
iv
EXECUTIVE SUMMARY vi
LO OBJECTIVEOFTHEMONITORINGSURVEY
1
2.0 METHODS 4
3.0 RESULTS 13
3.1 Side-scan Sonar 13
3.2 REMOTS®Sediment-ProfileImaging 13
3.2.1 Dredged Material Distribution andPhysical Sediment
Characteristics 18
3.2.2 Biological ConditionsandBenthicRecolonization 22
3.3 Towed Video Survey 28
3.3.1 SedimentComposition 28
3.3.2 BenthicMacrofauna 36
4.0 CONCLUSIONS 37
5.0 REFERENCES 38
INDEX
APPENDICES

LISTOFTABLES
Page
Table 1-L Summaryofdisposal operations overthe Morris Coveborrowpit
duringthe 1999-2000disposal season 2
Table2-1. MorrisCoveborrowpitREMOTS® SamplingLocations 7
Table 3-1. REMOTS® SUMMARYTABLEFORTHEMORRIS COVE
BORROW
PIT 14
Table 3-2. REMOTS® SummaryTablefortheNewHavenHarborReferenceArea 15