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2 1 and seafloor. onthecoasts oficeimpacts the intensity oficeformation andbased onthetypes propose azonation Bay ofBaydaratskaya frozenby iceridges into large floe. We executed dueto themaximumimpact rim, nearthe fastice ice gouging isobserved centimeters upto 2m;themostintensive fromthe depthofgougesvaries thefirst is described, generalized andsystematized: gouging byfloesontheseabedandshores Bay, Sea. Kara oficeThe directimpact inBaydaratskaya ice gougemorphology we present results from recent studiesof Heredepth raisesthecostofconstruction. overestimation leadingto excessive burial lead to theinfrastructuredamage, while of icegouging ontheseabedcan intensity shoreface are required. Underestimation scourontheseabedand of ice-keel andpenetrationdepthof thefrequency cables infreezing seas, reliable estimates pipelinesandcommunication underwater [email protected] A1B 3X9,Canada; e-mail: Telegrafenberg [email protected] A43,14473Potsdam, e-mail: Germany; [email protected]: ; * 119991 Moscow, Russia; Tel: 7495939-22-38;Fax: 7(495)932-88-36 intensity oficeinfluence,intensity zoning. ridges, icegouging, bottom topography, the dynamics, geotechnical safety, , ice 3 2 Stanislav Ogorodov 5 4 Paul Overduin 1 ABSTRACT. KEY WORDS: IN BAYDARATSKAYA BAY, KARA SEA ONICE COAST EFFECT AND SEABED Department ofGeography, Department University ofNewfoundland, Memorial St.John’s, NL, Alfred Wegener HelmholtzCentre Institute for Polar Research, andMarine The University Centre inSvalbard, Pb. 1569171Longyearbyen, Norway; Zubov 6,119034,Moscow, pereulok, State Oceanographic Institute, Kropotkinskiy Faculty ofGeography, Lomonosov Leninskiye Gory; Moscow State University; Corresponding author

e-mail: [email protected] e-mail:

For theengineering design of

4 Kara Sea, arctic coastal Kara , DonaldForbes 1* , VasiliyArkhipov : e-mail: [email protected] : e-mail: 5 2,1 ridges andgrounded ridges (stamukhi). ridges seabed forms associated with pressure processes ofbottom scourandrelated have documented theoccurrence and topic. andCanadianresearchers American ofresearchthere onthis isalonghistory abroad, especiallyinCanadaandtheUSA, and theseafloorincoastalregions, whereas seaice between Russia ontheinteraction Until recently, hasbeendonein littlework burial. crossing design, andrequired depthsof ofpipelinelandfallsites,selection shore- the determining factors the mostimportant 2006: Lananetal., 2011]. This isoneof coastal andseabeddynamics[Løset etal., information ontheeffects ofseaiceon islands)requirepipelines, new andartificial terminals, platforms, drilling submarine areas (includingnavigation channels, coastal engineering facilitiesinthecoastalandshelf ofrelevantgas fieldsandtheconstruction coasts. The ongoingdevelopment ofoiland role intheevolution ofnorthern important the highlatitudesofArcticseas, plays an Sea ice, asazonal associated factor with INTRODUCTION , OsipKokin 1 , Aleksey Marchenko 3,2 , 226.08.2013 9:22:11 6 . 0 8 . 2 0 1 3

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2 22 GEOGRAPHY 2 recorded [Lisitsyn,1994]. formations reaching 50mdepthhave been from oflarge submarines, hummock keels of grounding). directobservations In below thesealevel (muchdeeperinregions coastal zone outto depthsof55mormore inthe icegouging isobserved underwater et al., 1990;Forbes and Taylor, 1994],while Sodhi, 1980;Shapiro etal., 1984;Reimnitz and [Kovacs andiceride-up as icepile-up onto andacrosspush canextend the beach topography [Ogorodov, 2003].Icescourand hydrometeorological andcoastal factors hummocks (pressure controlled ridges) by (ridging), andformation ofgrounded cover dynamics andmobility, hummocking bythe ice seasisdriven floor oftheArctic surface. ontheshore andthe This impact ground oficeontheunderlying impact Ice gouging mechanical isadestructive ofmultiyear iceincursion. frequency 2004], possiblyrelated to areductioninthe a reductioningouging rates [Blascoetal., Sea,recognizingBeaufort theevidencefor depthsandscourfrequenciesextreme inthe Wadhams [2012]provides newestimates of pipeline protection from icegouging and provides arecent review ofissuesrelated to Sea.Barrette [2011] the CanadianBeaufort etal. [1991]for shelfandHill for theAlaska results were provided etal. byRearic [1990] <1 mbutasdeep7,6m.Later synthesesof depths ofscourpenetrationwere typically if thedepthrangeof15–40m,andthat out to about55mdepth,wasmostintense [1977] establishedthaticescouroccurred andBrown[1975], Lewis [1977],Hnatiuk byShearerSea, seminalwork andBlasco theCanadianBeaufort etal.,[Barnes 1984].In into thesea floor, andwere upto 67mwide were upto 2km indepthsof20–40m. highest density They at depthsof0-65m(afew deeper),withthe , icegougeswere found ontheseafloor later augmented diving surveys, bysidescan 1984]. With thehelpofechosoundersand etal., 1984;Barnes Reimnitz andKempema, Reimnitz andBarnes, 1974;Barnes, 1982; shelf[e.g. Carsola,1954;Rex,1955; Alaska onthe Pioneering studieswere undertaken long, incisedasde ep as2,5m order oftheiceon to assesstheimpact a10-yearcontinued in2005after hiatus. In coastal zone dynamicsandseaiceeffects renewing oftheproject, investigations of area is22–23m.In the maximumbottom depthinthecrossing ofthepipelineisapproximately 65km, part route (Fig.1). The lengthoftheunderwater ofRussiabytheshortest in theEuropean part the withthepipelinenetwork underway. gasfieldsofThis wasto connect pipeline across Bay was theBaydaratskaya crossing ofthemaingas of theunderwater revived andbyAugust 2007,theconstruction of whichwould cross Bay, Baydaratskaya was [Environmental conditions..., 1997],thelines 2005, the “Yamal-” pipelineproject capacity. To provide gasfor thispipeline, in 2013thispipelinewillreach full Sea. In Germany through theseabedofBaltic Pipeline” Russiaand directlyconnected 2011,theso-called In “Nord-Stream Gas Vershinin, 2006]. 2005;Zubakin, shelf [Environmental conditions..., 1997; Sea, thePechora Island Sea,andtheSakhalin Bay oftheKara (Baydaratskaya construction out intheareas pipeline ofsubmarine significantly later andwere started carried (firstofall, theeffectimpacts oficegouging) Russia,specialstudiesoftheseaice In Fig. 1. “Yamal-Europe” gas pipelines crossing crossing pipelines gas 1.Fig. “Yamal-Europe” Baydaratskaya Bay in the Kara Sea Kara the in Bay Baydaratskaya connection withthe connection 226.08.2013 9:22:11 6 . 0 8 . 2 0 1 3

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2 categorized asmediumfirst-year ice. does notqualifyasthickfirst-year iceandis only 120cm. The icecover in thatarea often is typically annual maximumicethickness Across thebay alongtheUralcoast, ofthick first-yearfits into ice. thecategory cm onaverage, i.e. theicecover ingeneral alongthe thickness Yamal coastreaches 140 theendofcoldseason,ice coast. By is generallygreater thanalongthesteep Ural alongtheshallow ice thickness Yamal coast to note thatthemean in May. isimportant It days inMarch, 2–4cminApril, and1–2 cm February andthendeclines to 5–6cm per10 10days by8–10cmfrom Novemberevery to increases typically formation. Icethickness correlatedand poorly to thedate ofstableice cooling surface oftheunderlying intensity to the isdirectlyproportional thickness growthstage, inice therate offurther theicecoverAfter reaches thegrey-white 15 days later theiceformation closeto shore. remote from theshore, occurs10– freeze-up more ofthebay seaward In December). parts occurs late (endofNovember oreven into dominates theautumnseason,iceformation airfrom contrast, whenwarm theAtlantic in (thefirst10days ofOctober); early starts or thecooledcontinentprevail, ice formation when coldairmassesfrom theArcticOcean the temporal seasons rangeoffreeze-up. In hydro-meteorological conditionsdetermine 15–20 October. Year-to-year inthe variations date for theformation ofstableiceisabout ice appears. The climaticmeanfreeze-up negative values, thefirst,usuallyunstable water temperature descendtosurface of October, astheradiationbalanceand ice, i.e. inopenwater. Atthebeginning Bay usually occursintheabsenceofresidual The autumniceformation inBaydaratskaya directly are presented inthispaper. inwhichtheauthorsparticipated the work of theresults andscientificconclusionsof as well asmathematicalmodeling. Some out,includingfieldstudies has beencarried sea bottom, awiderangeofinvestigations 3 ICE CONDITIONS 10 of1misapproximatelywith icethickness 300 m. diameter icefield The mass ofa1km reaches 30m,whilethelength canbeupto Bay, includingboththesailandkeel, inBaydaratskaya of pressure observed ridges of 6-10km. dimension The maximumvertical diameter (Fig. 2a),thoughseveral reach sizes in of theicefields(floes)are lessthan2km hasshownthatmost on satellite imagery Analysis oficefieldsize for 2006based April iceconsistsoffieldsdifferentDrift sizes. complex iceformations, together. whichdrift hummocks freeze into icefields, buildingup ice hummocks(pressure form. ridges) Ice well icefields, asontheborders ofdrifting fasticeandpackice, between as interface ice isgenerallyless. Alongthe of drifting in thesameequalconditions, thethickness ice. Compared withtheimmobilefastice, than 10–15m,isthearea ofmobilepack Bay,of Baydaratskaya indepthsofmore Outside thefasticelimits, thecentral part where itswidthisapproximately 5–7 km. to theisobathsof10–12moffUralcoast, Yamal and coast,where itswidthis7–9km, ice corresponds to theisobathof15mat February-March theseaward border offast and the8–10misobathinDecember. In reaching the5–7misobathinNovember spreads seaward quickly, itsouter border oftheseason,fastice part theearly In cases ofitsbreak-away have beenobserved. ice islessstableandinthelastseveral years, of thebay only. to theUralcoast,fast Next near the Yamal coastandintheinnerpart increases considerably. Stablefasticeforms ice conditions, thefasticeresistance stabilizing of icehummocksandstamukhas, (upto 0.5 ice thickness sea-level rise. However, withthegrowth ofsea it canbeeasilybroken unstable intheinitialstagesandtherefore This young, relatively thin,fasticeisvery ofapproximatelyup, withathickness 30cm. ice forms 20–30days theinitialfreeze- after ofthe open parts Yamal andUralcoasts, fast iceandfast(Fig.drift 2 Bay consistsof The seaiceofBaydaratskaya 6 tons. The massofthe lar m) and strong a ). Closeto the the formation wind shearor gest pressure gest pressure 226.08.2013 9:22:11 6 . 0 8 . 2 0 1 3

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2 24 GEOGRAPHY 4 2.7 ridge 30m ridge and seabedisstatisticanalysis ofdataonthe onthecoast assessment ofsea-iceimpacts The mostcommonlyusedapproach to the Yamal coastofthebay. fromconditions for theUral to icedrift the currents,of counteracting thesewinds create windsprevail. theabsence and southerly In thewinter season,southwesterly 2 m.During surges, thewater levels have arangeofupto tides)is1.1m,butincludingstorm (spring is 1,0mpersecond. The maximumtidalrange while themeasured maximumcurrent speed is0,5, thetidalcycle of thetidalcurrent during tide(Fig.semidiurnal 2 axis ofthebay. Currents are bythe driven are reversive practically andaligned longthe field. Currents period measured intheice-free oftheice on theupperandlower surfaces and currents andtheshearstress theyexert are thewind drift forcesThe driving ofice-field within them,ratherthanbyindividualridges. frozenassociated keels) inandincorporated pressure (icehummocks andtheir ridges is dominated bythemassoficefieldswith the icescourprocess Bay inBaydarakskaya etal,ice field[Marchenko 2007].Consequently, METHODS • a –ice conditions on06.03.1999: satellite TERRA image; 10 5 tons, far less than the mass of the 1 km tons, farlessthanthemassof1km Ѕ 30m Ѕ 300mistherefore about b ). The maximumspeed Fig. 2. Baydaratskaya Bay, Kara Sea: and is observed atthemonitor inreal time.and isobserved GPS/GLONASS goesto thecomputer module sonar,from theside-scan echosounder, and exceed Alltheinformation coming 4knots. of thevesseltracks shouldnot during accepting WAAS error corrections. The speed GPSandGLONASSmodern receivers, withhighprecisionis determined using The positionofthesoundingtracks same vessel. are executed atthesametimefrom the surveys sonarandecho-sounding Side-scan methods. results ofseveral complementary approach, whichallowsusto combinethe forms ontheseabottom, we useacomplex parameters oficegouging morphometric and themorphology and determining oftheicegouging microrelieffield surveys equipped withthesedevices(Fig. 3 fromconducted aspecialized research vessel Investigations ofthebottom icegouging are and GPS/GLONASS positioningsystems. profilerssidescan, acousticsub-bottom multibeam sounding, interferometric sonar,geophysical equipment–side-scan is possibleonlywiththeuseofspecialized ice gougesonanextensivearea ofseabed andpenetrationdepthof the distribution of over time. Acquiring awideknowledge features ofthisparameter andthevariability andparameters oftheicescour distribution b–tidalcurrents [Environmental 2007] conditions..., a ). For 226.08.2013 9:22:11 6 . 0 8 . 2 0 1 3

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2 of theicegouging forms (Fig. 3 andorientation the ideaofspatialdistribution sonargives bottom sediments;theside-scan etc.), aswell aswhethertheyare filledwith motion units tracking the motion unitstracking context ofclimate change,context identification measurements. thetwo thebetween In and to distinguishforms which appeared repeated to conduct soundings necessary of theicescouratpresent time, itis sounding tracks. To assesstheintensity ofrepeatingand thenecessity previous by proximity to theprojected objects resolution ofthesoundingsisdetermined pipelines) onthebottom. The spatial infrastructure(trenches,transportation ontheseafloorandoilgas impacts with theaimofassessingicegouging As arule, suchinvestigations are conducted (more commonly)combinationsofallthree. fromthe noisearising pitch, roll, yaw, or vessel improve byreducing quality survey morphometry ofthefo morphometry sounding profile and showsthemorphology the sonarequipmentsuppliers. An echo- providedhelp ofthelicensedsoftware by is registeredIt onthehard drivewiththe 5 Fig. 3. Geophysical survey technology for mapping seabed features including ice-gouging features: features: ice-gouging including features seabed mapping for technology survey Geophysical 3. Fig. b – selection of geophysical of devicesb –selection to dete rms ( rms a –research devices; vessel survey withgeophysical 3D mo depth, tion ofthe b ). Inertial ). Inertial width, frequent. water areas are andstorms are least ice-free July to thebeginning ofAugust, whenthe Russian Arcticisfrom the secondhalfof inthecoastaland shelfzone ofthe surveys the besttimefor geophysical conducting Accounting recent for climate changes, very parameters. on theicegouging forms, and distribution, data statistical processing ofmorphometric processing stream. survey enables This work only thefirststep inthecomplexgeophysical equipment shouldbeused. The fieldstageis the previous ones, of andthesametype shouldcoincidewith tracks ofnewsurveys are documented. For thispurpose, the investigations indifferent conducted years troughs whichhave appeared between and bottom sedimentfilloftheicescour and thenumber, depth,width,orientation thisstudy,In thepositionofpipeline towards shallower water. zone and displacingthemaximumimpact years causingchangesintheiceregime ofthelastfewlight oftheclimate warming of “fresh” in gougesisespeciallyimportant rmine therelevant ice of parameters forms 226.08.2013 9:22:11 6 . 0 8 . 2 0 1 3

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2 26 GEOGRAPHY 6 5 – hummock keel into penetration 5 –hummock ice theground; frozen 6–seasonally andbed; ice atcontact forming between ridges) areridges) measured. microforms created bythem(gouges, pits, andice hummockridges) stamukhi, parameters oficeformations (icepiles, stations, morphological andmorphometric free. UsingGPS/GLONASS andlasertotal directly before thewater area becomesice- are made As arule,performed. observations the seabottom, coastalinvestigations are Besides icegouging relief soundingon forms. speed ofsedimentationintheicegouging for experiments the determining perform samples,photo andvideoimagery, take and gouging forms. Divers acquire underwater of geophysical interpretation oftheice mostlyforis conducted theconfirmation which activity Diving isacomplementary current action. before theyare obscured bywave and new icescourfeatures formed bystamukhi fasticemelting,after inorder to identify from smallervessels immediatelyperformed sonarandanechosounderare side-scan GLONASS. Shallowwater soundingusing hummock ridges, whichare fixed withGPS/ and thepositionofstamukhi determining ice cover are conducted, withtheaimof reconnaissance investigations ofthefast high hydrodynamic activity, preliminary microforms donotremain stabledueto areas ofshallowwater,In where icegouging Fig. 4. Subdivision of coastal zone by types of ice formations and their effects on coasts and seabed: seabed: and coasts on effects their and formations ice of bytypes zone coastal of Subdivision 4. Fig. 4 – hummocks ice formations4 –hummocks (ice grounded ridges, 7 – tidal crack; 8 – high-salinity water inlongshore cryopegs troughs, 8–high-salinity 7 –tidalcrack; 1 –fast ice floes; frozen ice; to 3–drift 2–floating thebed; the beachsedimentsandforms of ridges push event, thesolidicecover off trims formation). anice- During pressure-ridge (equivalentto floe)orpile-up (unbroken onshore iceride-up through wind-driven sea ice(20–40cmthick)canbepushed (Fig. 5 formedoccurrence ofridges byice-push reveal thewidespreaddefined. Oursurveys material, oficepushisclearly theimprint On shoreline composedofsand-pebble andbreak-upfast-ice destruction inspring. of iceformationperiods inautumnand Sea coastsare affected the byice during topography changescausedbythem. oficeformations andbottomgeneral types coastal zone Bay andthe ofBaydaratskaya themechanismsandfeaturesobserve ofthe slope,offshore we can downtheunderwater mechanisms oficescour(Fig. 4).Moving formation aswell asunderstandingofthe model regarding ofice thecharacteristics have madeitpossibleto refine Sovershaev’s under theguidanceofleadauthor, in recentinvestigations years performed of Arcticcoastaldynamics. Detailed to studies has madeahugecontribution [Environmental conditions..., 1997],who coasts andfloorwasby V.A. Sovershaev formation andtheireffect onthesea ofice Bay bythetypes of Baydaratskaya The firstsubdivisionofthecoastalzone RESULTS AND DISCUSSION hummocks andice dam),hummocks ice andoverthrusts; piles а ). In autumn and early winter, autumnandearly ). In young 226.08.2013 9:22:12 6 . 0 8 . 2 0 1 3

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2 is preceded of beaches bythefreeze-up areas. The development ofbottomfast ice and thedevelopment ofnewpermafrost induces thefreezing ofbottom sediment the nearshore andinopen shallowareas 1988]. The presence of bottomfast icein Bay [Sovershaevof Baydaratskaya etal., are widelyrecognized intheshallowareas beneath theseabed. These phenomena ofrelictpermafrost and thepreservation the formation ofseasonallyfrozen ground where theicebecomesbottomfast, allowing effects ofseaiceareThe thermal alsoimportant bent nearthebase(Fig. 5 lower than2,5ma.s.l.the benchmarks are give evidenceoftheseprocesses. of Most Bay,Baydaratskaya geodeticbenchmarks andinfrastructuredamage.scouring In hundreds ofmeters, whichcausessurface brought inlandasfartens andeven surges, highstorm during seaicecanbe lowlandsthatcanbeflooded On maritime considerable storm. forms, untilthefirst are usuallypreserved forms, alongwithmostoftheicesqueezing transverseoriented to thecoastline. These icegougesare <50m.Most is typically not usuallyexceed 0,5–1,0m,andthelength Taylor, 1994]. The depthoftheseforms does which appearonsandybeaches[Forbes and ridges, allof ice-pushed and alsovarious as furrows, striations, wallowdepressions the icealsoproduces small-scaleforms, such spring [Barnes, material 1982].In unsorted 7 b – coastal dynamics monitoring network b –coastal monitoring network dynamics b a – ice-pushed ridge (photo ridge by N.V.Kopa-Ovdienko),a –ice-pushed ). Fig. 5. 5. Fig. bench mark damaged by seaice markdamaged overthrust bench troughs, icereaches whenthethickening formation occurinthelongshore cryopeg Similar conditionsfavoring thecryopeg. leading to theformation ofthe so-called fall belowthefreezing pointofseawater, values; therefore, thewater temperature can water intheseclosedareas exceeds average sea [cf. Grasbyetal., 2013]. of The salinity regimes different from thoseintheopen and acquire theirownsaltandtemperature almost completely isolated from thesea theseareasmaximum thickness, become end ofwinter, whentheicereaches its the itsformation.the fasticeduring By lagoons intheform ofsaltdepletionin shallowsand can beseeninnear-coastal The chemicaleffect ofseaiceonfloor into thesea(Fig. 6). zone andprotrudingthe landfasticecontact reveals a “cap” from frozen-ground forms in ofthiswater.salinity The nearshore profile ofunfrozenproportion water, andincreased through increased temperature, ahigher subaqueous features, whichare expressed the seafloorgradually acquires specific below 0°Cto –2°C. The permafrost underlying alternate withunfrozen grounds cooled the areas offreezing. These grounds often formation ofsubaqueousfrozen grounds in the icethickness. This process results inthe sea depthbecomesequalto orgreater than from thewater edgeandgoingonuntilthe ice freezes just to bottom sediments, starting protective cover. autumn,developing fast In and tideflatstheformation ofanice 226.08.2013 9:22:12 6 . 0 8 . 2 0 1 3

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2 28 GEOGRAPHY 8 during storms.during windscandestroy Storm thelocationoffasticeedge particularly and controlled byhydrodynamic factors, pressure isirregularhummocky ridges Further out inthebay, of thepattern autumn. with thefirststrong waves insummerand is mainly<0.5m,commonlydisappear storm. These forms, thedepthofwhich untilthefirstsummer short, areas isvery developed onsandbeaches andshallow forms ofice-gouged The life expectancy only immediately fasticeisdestroyed. after (down to adepthof7–10m)canbetraced onbeachesandinshallowareas barriers and effect ofthecoastalhummockridges to thecoastline. normal mostly oriented The ofseaice, ice gougesinthiszoneimpact are bars.submarine Dueto theonshore pushing commonly corresponds to thenumberof and, thusthenumberofhummock ridges these bars, theybecomethefocus ofridging Because ofadecreased seadepth above bars[cf.above submarine Forbes etal., 2002]. hummocks closestto thecoastdevelop asaprotective buffer.serves of The ridges in thenearshore zone, ofice thisnewstrip ice. young After icefreezes to theseafloor formation untiltheseaiscompletely free of sea bottom lastsfrom theonsetofice oftheiceon The mechanicalaction protects bottom ground from freezing. water which They getfilledwithhigh-salinity troughs alsobecomeisolated from thesea. [Grigoriev, thiscase, thelongshore 1987].In the seafloorandfreezes to longshore bars Fig. 6. Geocryological section of the Yamal coast of Baydaratskaya Bay, Kara Sea: Sea: Bay, Kara Baydaratskaya of Yamal coast the of section Geocryological 6. Fig. 1 – permafrost, 2 – seasonally frozen 2–seasonally layer,1 –permafrost, 3–seaice, 4–cryopegs 14–16 m (within Baydaratskaya Bay), the 14–16 m(withinBaydaratskaya only. storms extreme during Atdepthsof this depth. smoothed They canbepartly (Fig. 8 of parallelicegougesupto 1,5m deep and 400mlong;itconsisted ofasystem dimensions ofapproximately 70mwide from theresearchsonar tracking vessel 2007,during of icefrom theopensea.In to thecoastlineduetonormal thepressure form aso-called “comb”, usuallyoriented the winter (Fig. 8 the floor(“ice dam”) develop throughout strongest. Here, pressure reaching ridges ontheseafloor is the where theiceimpact near the10–15misobaths)iszone Bay The fasticeedge(withinBaydaratskaya in thezone ofthefasticeedge. inshallow areas islowergouge density than smoothed,the gougesareand quickly Due to highhydrodynamic here, activity by thepressure oficefrom theseaward side. to thecoastline,normally whichisenhanced area are mostlyeitherchaotically or oriented gouges remain (Fig. 7 deep) holesandshallow, ice relatively short and wave small(upto 1m destruction, down to thebottom. theirmelting After remain non-mobile, frozen often stamukhi thefinalonsetoffastice After ofhummock formations.along-shore drift the coastline. This isdueto theprevailing this caseiseitherchaoticorparallelto (Fig. 7 hummocks orsinglegrounded hummocks the fasticeedgeandform of anewridge Petrov , sucha “comb” with wasobserved b a ). Icegougesare at well preserved ). oficeplowinginThe pattern a ). In thiscase, icegouges ). In b, c b, ). Icegougesinthis 226.08.2013 9:22:12 Ivan 6 . 0 8 . 2 0 1 3

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2 The above situationisdueto more active and grounded hummocksare formed here). (most ofthemobilesystems ofhummocks though icegouging isthemost intense out to belower thanatgreater depths, oficegougesturns occurrence anddensity 9 Fig. 7. Grounded hummock (stamukhi) (photo by A.А.Ermolov) and its effect on the seabed (as distinct from their short existence in from theirshort (as distinct over several years –firstdecadeyears here Due to this, thegougesatdepthcanexist and thevelocities oftidalcurrents are higher. the wave effect stillinfluencesthebottom hydrodynamics atshallowdepths, where 226.08.2013 9:22:13 6 . 0 8 . 2 0 1 3

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3 30 GEOGRAPHY 0 participates intheicegouging,participates thedeepest whole iceformation (floeandhummock) (Fig. that themassof 9a).Given thefact reaching thebottom frozen into themdrift and alongwhichicefieldshummocks, thewholecoldseason going onduring coast fast-ice where rim, icehummocksis depths from to the 16to 19m,next Yamal iceattherangeof occur inthearea ofdrift The mostintensive anddeepicegouges and vanishing. shallow areas), gradually smoothingover Fig. 10. Iceberg at the pipeline route “Yamal–Europe”, May 2007 (photo byA.M. Kamalov) (photo 2007 May “Yamal–Europe”, route pipeline the at 10. Iceberg Fig. Fig. 9. Ice gouging by hummock frozen into the floe the into frozen byhummock gouging 9. Ice Fig. Fig. 8. Ice dam and its effect on the seabed the on effect its and dam Ice 8. Fig. bottom [Ogorodov, than19 2003].Deeper Sometimes theycover upto 100%ofthesea bottom andare mostlysuperimposed. ice gougesare onthesea well preserved low.sedimentation are very As aresult, unaffected bywave therates of action, low hydrodynamic atthesedepths, activity etal.,Bay [Marchenko 2007].Dueto the directions –lengthwise theBaydaratskaya are conformably oriented withtidalcurrents inthisarea (Fig.been observed 9 icegougeshavelongest (upto several km) (up to 2m),thewidest(upto 50m)andthe b ). They 226.08.2013 9:22:13 6 . 0 8 . 2 0 1 3

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3 Sea show that the depth of ice gouges and Sea showthatthedepthofice gougesand Bay,Investigations on theBaydaratskaya Kara water area. thetimeofminimumicecover ofthe during andoccurs periods tois connected warm ispossiblethattheappearanceoficebergs It rarely, including in1932and2007(Fig. 10). Bay documentedin Baydaratskaya very . Icebergs have beendocumented that icegougesatthesedepthsare by left here.rarely observed The hypothesis is bottom icegouging stops. Icegougesare 23–26minthisarea, hummock thickness, At depthsexceeding themaximumpossible of icegouging here. effect gives afalseimpression ofahighintensity the longlife ofgougeforms. This “accumulation” oficegouginglow intensity iscompensated by for decades. exist onthebottom surface Thus, a conditions, thegouges, especiallylarge ones, can andlowsedimentationrates. Undersuch activity This situationiscausedbyalowhydrodynamic ice formations rarely occuratthesedepths. m, ice 1 Fig. 11. The distribution of the density ( density the of 11.Fig. distribution The gouges occurratherfrequently. However, a ) and depth ( depth ) and was found field dataonthe between as well. However, nosimplecorrespondence granulometric compositionofthesediments depends onplasticity, and mobility The shapeoficegouging forms probably composition andstate ofbottom deposits. ofsheerstress,intensity butalsoonthe and not onlyonseadepth,icethickness The depthoficegouging forms depends [Ogorodov, 2011]. problem oficegouging forms’ preservation and bottom withthe isdirectlyconnected about seaicegouging ofthecoasts intensity period,dynamically active sothequestion ofthesedimentsandduration type according to seadepth, essentially vary Meanwhile, thelifetime ofsuchforms can estimation oficegouges’ anddepth. density estimation oficegouging isthe intensity ice gouges. The mainmethodofindirect with rarer occurrence andsmallerdepthof of icegouging islower inshallowdepths highest valuesatdepthsof17–19m(Fig. 11 oficegouging formsthe density reach their However, thisdoesnotdenote thattheinte b ) of the ice gouges with sea depth sea with gouges ice the ) of nsity nsity a , 226.08.2013 9:22:14 b 6 . ). ). 0 8 . 2 0 1 3

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3 32 GEOGRAPHY 2 of ice gouging impact. Keels theice of iceof impact. do formations gouging mostly frozen into withtidalcurrents; andremnants theice icebergs of fields 7 drifting – area of drifting ice out of the zone ice ice Formation big of currents; area. gouges 6–drifting most intensive ice is caused gouging by thekeels theice of the ice cover towards ice of hummocks thelandand action atthefast ice bott iceof of intensity hummocks rim.High thestages of fastpressure attheforming ice rim,reflecting alongthecoast, “ice andseparatedeveloped st barriers” thefast of limited ice; by thestableness 3– andimmobility andstamukhiSea ice ridges aresi formations: hummocks withsites ne to wheretheicesbottom” theground freezes andforeshores beaches 1 –seaice onlowcoasts, overthrust lengths, sometimesupto several kilometers, especially large ones, have considerable showsthaticegouges, cases. Observations few ofsediments, type except inavery ofgougesandthe occurrence anddensity Fig. 12. Map of the arias with different intensity of the sea ice impact on the coasts and bottom bottom and coasts the on impact ice sea the of intensity different with arias the of 12. Map Fig. of Baydaratskaya Bay, Kara Sea. Legend: characteristics ofthesediments. characteristics withratherdifferentgouge bottom sections energy.kinetic Therefore hummockcan bottom for a longtimedueto theirlarge i.e. hummockscanconstantlygougethe om ice gouging as a result of pressure-forced movements of of movements pressure-forced asa result ice of om gouging n’t reach the bottom. ice of is low gouging probability The ar the water edge, on underwater bars and shallow gulfs. andshallow gulfs. bars ar thewater onunderwater edge, its prorogation. Ice intensity is medium; gouging prorogation. 4–area its amukhi correspond to the periods of contraction of correspond toamukhi theperiods dueto by the keels of heavy low-sitting hummocky formations hummocky low-sitting by thekeels heavy of hummocks, frozen intohummocks, theice area of unstable “floating” fast ice. Ice hummocks ridges tuated on underwater coastal bars. The ice is The gouging coastaltuated onunderwater bars. area; development 2–areaof stable of fast ice “on the drifting alongthefast ice ice The area. drifting rim; 5–drifting floe drifting withthetidal drifting floe 226.08.2013 9:22:14 6 . 0 8 . 2 0 1 3

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3 laying the3 to while considertheicefactor necessary are situated inthiszone. Therefore itwillbe pipelinecrossing underwater “Yamal-Europe” ofthe parts Most along thefasticerim. with thehelpoftidalcurrents which drift hummock formations frozen into them, 20 mdepth–thearea oficefloeswith thestrongestat15- experiences impacts withinthebay.selected The seabottom considerably, vary haveice impacts been ofthe the mechanismsandintensity developed (Fig. 12).Several zones, inwhich Bay,Baydaratskaya Sea” Kara hasbeen onthecoastsandbottom ofthe impact in 2005–2012,amap-scheme “Sea ice obtainedasaresultfrequency ofexpeditions statistical processing oftheicegouges’ andresultsconditions, of bathymetry Based onanintegrated analysisofice At the depthsofmore than14mfor – For Bay icegougescanbe Baydaratskaya – Coasts 2mabove between sealevel and – following conclusionscanbedrawn: zoning ofthepipelinecrossing area, the Bay,Baydaratskaya Sea,andonthe Kara onthecoastsandbottom of ice impacts Based onadetailedanalysisofthesea for seabottom icescourmonitoring. a sheetofpaper”“blank andanidealpolygon pipelines have already beenbuiltare literally pipeline andthecovered trench where the over thembyiceformations. The buried anddepthofbottom disturbance frequency the already laidpipelinerunsto establishthe well of constantmonitoring asto conduct 3 CONCLUSIONS

main controlling ofthebottom factor infer thatatthesedepthsgouging isthe most frequent bottom features, which the Yamal ice gougesare section, the andmore than12mforthe Uralsection long; kilometers up to 2mdeep, 50mwide, and several influence ofseaicescourorgouging; the 26 mbelowsealevel experience rd andthe4 th pipelinerunsas Excellence. ofCenters of and theCanadianNetworks Forbes byArcticNet by Donald issupported Technology” projects. Participation (SAMCoT) and andCoastal “Sustainable ArcticMarine JointResearchGerman Group, HGF-100” Russian- “Helmholtz Developpement, Permafrost Dynamics” Total E&PRecherche Peninsula: Environmental Conditions and Russia” (#8508), “Coastal Zone of Yamal academic teaching staffoftheinnovative Federal Target Program “Scientific and by supported waspartially This work – The underwater pipeline The underwater “Yamal- – The highesticegouging occurs intensity – Taking into considerationthevarying – With increasing depth,the “life span” of – gougeshave a 80%oftheobserved – ACKNOWLEDGEMENTS

bottom isalsonecessary. onthe oftheiceimpacts monitoring depthsforburial thepipes. Constant be considered whenprojectingthe most dangerous area; thisshould Europe” crossing issituated inthe area;drift-ice off the Yamal coastandintheadjacent ofthelandfastice along thewinter rim the icegouges; of solely fromorfrequency thedensity cannotbedetermined the iceimpacts of theicegouging forms, of theintensity hydrodynamic anddifferent activity “age” artefacts; the seabediscovered bythesegouging years; andfor someoftheareas 100%of forcan bepreserved tens to hundreds of the icegougesalsogrows, suchthatthey Bay oftidalcurrents; andthe pattern shape andalignment ofBaydaratskaya close to it), consistent withthegeneral (or orientation –south-east north-west processes; bywaveice gouging relief isre-worked relief formation. For shallower depths,  226.08.2013 9:22:15 6 . 0 8 . 2 0 1 3

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3 34 GEOGRAPHY 4 Sea// J. intheCanadianBeaufort (1977)Seabottom scouring andBrown, K. Hnatiuk, 12. P.R., Hill, Blasco, S.M.,Harper, J.R. andFissel,11. D.B. (1991)SedimentationontheCanadian Grigoriev, N.F. (1987)Permafrost of atthecoastalpart Western Yamal10. //Proceedings of Grasby, S.E.,Smith,I.R.,Bell, T. andForbes, andmirabilite D.L. pre- brine (2013)Cryogenic 9. Forbes, D.L., Chagnon, R.,Solomon,S.M.,vanderSanden,J.J. G.K., Manson, andLynds, T.L. 8. Forbes, D.L. and Taylor, R.B. (1994)Iceintheshore zone ofcold andthegeomorphology 7. Environmental Bay. conditions oftheBaydaratskaya results Main ofinvestigations for 6. Sea// Carsola,A.J. ofglaciationonthecontinentalshelf intheBeaufort (1954)Extent 5. Blasco, S.M.,Shearer, J.M., Campbell, P., Wright, B. insea andMelling, H.(2004)Reduction 4. Barrette, P. (2011)Offshore pipelineprotection againstseabedgouging byice:anover- 3. Barnes, P.W.,2. Rearic, D.M. andpro- andReimnitz, E.(1984)Icegouging characteristics Barnes, P.W. //Arctic, v. Sea,Alaska boulderridge, Beaufort 35, ice-pushed (1982)Marine 1. 1. ei, C.F Lewis, 15. Lanan,G.A.,Cowin, T.G. Seapipelinedesign, Beaufort andJohnston, D.K. (2011)Alaskan 14. models, fieldobservations, Kovacs, A.andSodhi,D.S. andride-up: (1980)Shore icepile-up 13. 17. Løset, S; Shkhinek, K.N; Gudmestad, O.T; K.N; Løset, Høyland, S;Shkhinek, K.V. from (2006) Actions IceonArctic 17. A.P. Lisitzyn, (1994).Sea-ice sedimentationinthe World 448p. Moscow, Ocean. (in Nauka, 16. REFERENCES Proceedings 9 Shelf//Continental ShelfResearch,Beaufort v. 11,N8–10,p. 821–842. ofPermafrostthe Institute ofthe USSR. Yakutsk. 112p. (inRussian). Harbour, western CanadianArctic//GeochimicaetCosmochimica v. Acta, 110,p. 13–28. cipitation formed transgression bymarine basins–Sachs ofhighlatitudecoastallake Engineering andResearch,tion ofHydraulic Dunedin,NewZealand, p. 344–351. Environment: Proceedings, Associa- SymposiumonIce. International 16thInternational (2002) Nearshore GulfofSt.Lawrence iceandclimate changeinthesouthern //Iceinthe coasts //Progress inPhysical Geography, v. 18,N1,p. 59–89. passage)(1997).Moscow, ofsubmarine construction GEOS,432p. (inRussian). Amer. J. Sci.v. 252,N6,p. 366–371. C43A-10. physical Meeting, abstract Union,Spring Geo- Sea. American rates ontheseabed1979–2003,CanadianBeaufort ice scourimpact view //Cold Regions Scienceand Technology, v. 69,N1,p. 3–20. Schell, E.Reimnitz).Academic Press, Orlando, p. 185–212. cesses. Sea:Ecosystems andEnvironments In: Beaufort (eds.The Alaskan P.W. Barnes, D.M. N 2,p. 312–316. the ice scour tracks in the Canadian //Proceedings,the icescourtracksinCanadianBeaufort 4 Texas, February 7–9.Offshore Technology Conference, 9p. installation andoperation.//Proceedings ofOTC Arctic Techology Conference, Houston, theoretical analyses//Cold Regions Scienceand Technology, v. 2,p. 209–288. Offshore and Coastal Structures, St.Petersburg: LAN.ISBN5-8114-0703-3. 271p. Russian). Engineering under Arctic Conditions,on Port andOcean St.John’s NL,v. 1,p. 568–579. .M. (1977) Estimation of the frequency andmagnitudegroundings.M. (1977)Estimationofthefrequency drift-ice from th Annual Offshoe AnnualOffshoe Technology Conference, Houston, v. 3,p. 519–527. th International Conference International 226.08.2013 9:22:15 6 . 0 8 . 2 0 1 3

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3 31. Zubakin, G.K. (ed.) (2006)Iceformations inthe G.K. Zubakin, Western seas. Arctic St.Petersburg. AARI. 31. Wadhams, P. depthsandscourfrequencies keel for (2012)Newpredictionsofextreme 30. Vershinin, S.A., Truskov, P.A.,29. Kuzmichev, K.V. at (2005)Iceeffect ontheconstructions Sovershaev, V.A., Voskresenskiy, F.A. Kamalov, A.M.,Romanenko K.S., (1998) 28. The develop- Shearer, J.M. phenomenon andBlasco, ofthescouring S.M.(1975)Further observations 27. Shapiro, L.H.,Metzner, R.C.,Hanson,A.andJohnson,J.B. (1984)Fast icesheetdeformation 26. Rex,R.W. (1955)Microrelief produced byseaicegrounding SeanearBar- intheChukchi 25. Reimnitz,E.,Barnes, P.W. andHarper, J.R. (1990)Areview from ofbeachnourishment ice 24. E.W. Reimnitz,E.andKempema, (1984)Pack Shoal, Beaufort withStamukhi iceinteraction 23. Reimnitz,E.,Barnes, P.W. Seashelfof (1974)Seaiceasageologic agentontheBeaufort 22. Rearic, D.M., Barnes, P.W. andReimnitz,E.(1990)Bulldozing andresuspension ofshallow- 21. Ogorodov, 20. Ogorodov, S.A. Press, University The RoleofSeaIceinCoastal–Moscow Dynamics. 2011, 19. 1 . Marchenko, A.V., Ogorodov, S.A.,Shestov, A.V. and Tsvetsinsky, A.S.(2007)Icegouging18. in 5 272 p. (inRussian). v. 76–77,p. 77–82. statistics//Cold Regions Scienceand Seausingicethickness the Beaufort Technology, shelf.Sakhalin Moscow: “Giprostroymost Institute”, 208c. (inRussian). Russia. Ed. V.I.Solomatin and V.A.Sovershaev. Moscow. MSU. P. 80–92.(inRussian). ment ofcoastalaccumulative oftheArcticcoasts forms inpermafrost //Dynamics ofCanada,Paper Sea.Geological Survey in theBeaufort 75-1. ments (eds. P.W. Barnes, D.M. Schell, E.Reimnitz).Academic Press, p. Orlando, 137–157. Sea:Ecosystems andEnviron- Beaufort Alaskan In: andshore iceride-up. ice-push during row, //Arctic, v. Alaska 8,N3,p. 177–186. p. 439–470. ofCoastal Research, //Journal v. ofshoreface materials,Sea,Alaska Beaufort transport 6, Schell, E.Reimnitz).Academic Press, p. Orlando, 159–183. Sea:Ecosystems andEnvironments Beaufort (eds. Alaskan P.W. In: Sea, Alaska. Barnes, D.M. p. Arlington. America, 301–353. ofNorth Institute // Alaska Sea(eds.The Coast andShelfoftheBeaufort J.C. ReedandJ.E. Sater). Arctic Geology,Marine v. 91,p. 133–147. // trajectories sediment transport implicationsforshelf sedimentbyicekeels: particle Water Resources, v. 30,N5,p. 509–518. 173 p. ISBN978-5211-06275-7. (inRussian). Dalian, P. 747–759. June 27–30.Edited byQianjin Yue Shunying of Ji.DalianUniversity Technology Press, ofOffshore Engineering“Recent Development inCold Regions”, POAC-07, Dalian,China, of 19 simulations//Proceeding Sea:fieldstudiesandnumerical bay oftheKara Baydaratskaya th International Conference International Engineering UnderArcticConditions onPortandOcean S.A. (2003) The Role of Sea Ice in the Coastal Zone Dynamics of the Arctic Seas // // S.A. (2003) The RoleofSeaIceintheCoastal oftheArctic Seas Zone Dynamics 226.08.2013 9:22:15 6 . 0 8 . 2 0 1 3

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3 36 GEOGRAPHY 6 Vasiliy V.Arkhipov Stanislav A.Ogorodov Aleksey V.Marchenko Osip V. Kokin of western shelfof Yamal Peninsula (2012,withco-authors). relief Ice Floes ice-gouging (2010,withS.A.Ogorodov); Modern byHummocky publications:CaspianSeaBottom Scouring Main sediments. coastal dynamics, shelfpermafrost andquaternary Oceanographic Institute. Area ofhisscientificinterest isArctic State University. Since 2010heisaLeading ScientistoftheState (2011). Dynamics inthePechorastability Sea(2005); The RoleofSeaIceinCoastal oncoastal dynamics oftheArctic Seas(2003);Human impacts seabed. publications: Main The role ofseaiceinthecoastalzone scientific interest isArcticcoastaldynamicsandiceeffect on a Leading ScientistattheMSUFaculty ofGeography. Area ofhis State andcommencedPh.D. University in1999.Since2004heis gravity waves (2013, withco-authors). sea-ice flexuralstiffnessbypressure offlexural- characteristics Measurements of K.); and analysisofmodeltests (2012,with Eik, (2008); Iceberg mathematicalmodelling towing onopenwater: consolidationandmeltingofseaiceridges Thermodynamic mechanics ofseaiceandArctictechnology. publications: Main Svalbard, Norway. Area ofhisscientificinterest isphysics and in 1997.Since2006heisProfessor Centre oftheUniversity in State andcommencedPh.D. University in1987andDr. Science advancein West Spitsbergen (2011). of surging (2011); The evidencesofthePre-Holocene ice. publications:Geological Main andgeomorphologic effects his scientificinterest isgeomorphologic effect ofglaciersandsea Scientific Researcher attheMSUFaculty ofGeography. Area of andcommencedPh.D.University in2010.Since2010heisa graduated from theLomonosov State Moscow graduated from theLomonosov Moscow graduated from theLomonosov Moscow graduated from theLomonosov Moscow 226.08.2013 9:22:15 6 . 0 8 . 2 0 1 3

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3 7 cycle (2007,withco-authors). cycle coastal andoffshore thelastclimatic permafrost Seasduring intheLaptev andEast Siberian Donald L.Forbes Pier P. Overduin geomorphology ofcoldcoasts(1994,withR.B.geomorphology Taylor). Review andOutlook(2011,editor); Iceintheshore zone andthe Glaciated coasts(2012);State oftheArctic Coast 2010:Scientific publications:PolarMain coasts(2012,withJ.D. Hansom); Newfoundland thecoastalproject inArcticNet. andco-leads ProfessorHe isanAdjunct of University at Memorial andadaptation. impacts paraglacial coasts, andclimate-change 31yearsof Canadaafter ofresearch oncoastaldynamics, 2012heretiredColumbia in1981.In from theGeological Survey Evolution anddegradationSea) (2012,withco-authors); of near-shore Beaufort permafrost atBarrow submarine (Alaskan ofthedegradation of observations Geoelectric co-authors); permafrost coastsintheLaptev Searegion (2013,with of ice-rich thermo-erosion andlong-term Arctic. publications:Short Main focuses permafrost andcoastaldynamicsinthe onsubmarine for Polar Research inPotsdam, andMarine Germany. research His attheAlfredPeriglacial Research Department Wegener Institute Fairbanks in2005.Since2006heisaSeniorScientistthe in Canada,andcompleted aPh.D. ofAlaska attheUniversity studiedat and Wilfrid Laurier York Universities obtainedhisPh.D. ofBritish attheUniversity 226.08.2013 9:22:16 6 . 0 8 . 2 0 1 3

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