BREAM_BBP 2006-004

8/14/2019 BREAM_BBP 2006-004

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Report of Norwegian Crown Ship Grounding

Thad Murdoch, Jack Ward, Annie Glasspool, Sarah Manuel and Mark Outerbridge

28th

June 2006

This report aims to document the location of the June 8th 2006 grounding of the cruiseship Norwegian Crown, describe the site conditions found after the ship was successfullyre-floated, and present remediation options and recommendations.

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Location:

The vessel ran aground on the eastern side of Dundonald Channel near the northern endof the dredged channel. Figure 1 below depicts this grounding site as yellow lines. In thisimage the channel shows clearly as the dark blue swath running approximately north-south. The dark brown patches to either side of the channel are live reef surrounded by a

shallow sandy seafloor. The grey-blue patches within the sandy zones are seagrass beds.This photograph is part of an aerial photo-mosaic created from images taken in 1997.

Figure 1 – Dundonald Channel with grounding site indicated.

Careful examination of this image reveals a gradation from dark to light blue in thebackground colouration underlying the yellow lines that depict where the ship came torest. The darker colour to the north represents deeper water. This reflects the fact that theship travelling south struck a sloping bottom and ran up this slope until cleaving andcoming to rest on a substantive patch reef.

Site conditions: The ship hit a shoaling sand bar leaving a clear impact scar in the form of a trench in this

soft material for approximately 120m. It encountered and broke a small patch reef in two,displacing half of this reef 40 – 50m prior to striking and coming to rest in contact with asecond, larger reef. This second reef was also split in two with the larger portion of thereef remaining in situ but shattered, whilst the smaller portion was pushed forward on thebow until the vessel came to rest. Figure 2 below provides an overview of the impact sitewhilst Figure 3 illustrates the location in higher detail.

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Figure 2(a) – Site map depicting approximate locations of major features (scale is

approximate as is location of bathymetric contours)

Figure 2(b) – Close-up site map detailing major features.

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Over the entire area there are many soft corals which have become unattached from thesubstrate, and in close proximity to the actual grounding site much of the hard corals havealso been shattered. These reefs were clearly dominated by soft corals and branching hardcorals. This is typical of coral reefs living in high sedimentation areas. These silt-tolerantcorals had become established on a foundation of massive dome-forming brain corals

which may have been killed many years ago from the increased siltation caused when thisactively used shipping channel was created. Many of these highly branched corals havebeen shattered by the cruise ship’s impact and remain as flattened shards of once complexstructures.

Anecdotal information indicates that this was recently a thriving reef which made a greatinshore dive site in the winter. The reef has been dramatically changed with very littlelive coral remaining. Much of the reef today reveals the underlying structure of ancientcoral skeletons. This is very clean calcite substrate presenting a complex three-dimensional nature which will probably form good settlement sites for coral recruits.Much sediment was moved during the effort to re-float the vessel and this has inundated

some adjacent coral reefs.

Figure 3: Ancient Coral Skeletons and Soft Corals Strewn over the Impact Site

(A Survey Tape Marks the Mid-line of the Scar)

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Extent of the impact:

The site was mapped in order to document the area affected by the ship grounding andsubsequent recovery effort. A grid was established over the site with the scar made by the

ship’s keel forming the baseline. This baseline was extended for 30m beyond the pointwhere the ship’s bow came to rest. At right angles every 10m along this line, 200mtransects were surveyed extending 100m to both the west and east. These transects wereshortened whenever the line ran out of the area of impact or into the channel.

At every 10m along these transects the degree of impact was assessed on a scale of 1-3and the nature of the substratum (rubble, sand, seagrass or coral) was recorded. Eachpoint sampled was taken to represent the 10m x 10m cell in which it was recorded. Figure4 presents the results of this survey.

Figure 4: Assessment of the extent and severity of the impact on benthic

communities.

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The most dramatic feature of this site is the remarkable scar left where the ship actuallycame in contact with the bottom. This is an area of complete destruction. The shipliterally ploughed through, leaving a deep furrow and shattered corals. Our estimate of the “scar” or the area destroyed as a direct result of the ship running aground is 1,100m2.

Figure 5: The Ship left a Deep Scar in the Sea Floor

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Figure 6: Shattered Corals at the Site of Impact

The survey revealed that an additional 3,900m2 was heavily impacted, having clearlybeen exposed to extreme currents which scoured sand and rubble from the seafloor,

bombarding nearby reefs and subsequently settling to smother adjacent reefs and seagrassbeds. Amongst the areas further from the source of this blasting action, an additional2,300 m2 was classified as moderately and 2,900 m2 as lightly impacted. Whilst ourmethodology classified areas beyond these zones as “no impact”, at many locationswithin this area we observed clear but scattered evidence that disturbance had occurred.

From this analysis we conclude that an area of at least 10,200m2

was impacted as a resultof this ship grounding and the subsequent re-floating effort. Of this, 1,100m2 orapproximately 10% was completely destroyed by the actual grounding whilst theremaining 90% of the area was impacted to various degrees by the salvage operation.

Remediation Options:

In jurisdictions where there is clear legislation which holds the owners of ships that runaground liable to fund restoration projects, businesses have developed to perform thisservice. Whilst full recovery of impacted systems will take time there are several well-tested methods to hasten this process. One key variable determining the success of remediation efforts is timely response. In locations where trained labour and legalincentives exist this is often initiated within days of the grounding.

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Despite the time which has passed since the Norwegian Crown grounding, live soft coralsremain scattered over the area. Many of these could probably be reattached to theremaining reef structure with a fair degree of success. This would improve the habitat forthe abundant fishes at this site. This work is labour intensive and a rough estimate of thecost is $25,000. This would provide for a first level of remediation. A full-blown

restoration and compensation package for environmental damage as would be required inmany jurisdictions could easily be an order of magnitude more expensive than this.Costing of full-service remediation would require a formal RFQ to contractors withexpertise in this area. The most likely source of such expertise in this part of the worldwould be Florida.

Figure 7: Some of the Dislodged Soft Corals adjacent to the Impact Site

The results of the survey to assess the extent of biocide contamination of the site are not

yet available. However, there is a patch of antifouling paint coating approximately 20square metres of the sediment the on the west side of the main furrow. This may present apotential for removal of a significant proportion of the biocide contamination of the site.The most effective method of accomplishing this is not known to us. However it doesappear that this may be a feasible endeavour. It is proposed that no action be taken on thisaspect of the grounding impact until results documenting the extent of contaminationhave been scrutinized.

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Recommendations:

It is our recommendation that clear guidelines for responding to ship grounding events bedeveloped. It is proposed that this guidance follow the form of the very effective oilpollution contingency plans. Such an integrated plan is essential to ensure that due

consideration is given to; safety, legal responsibility, continuity of essential services, andenvironmental impacts.

Examples of some of the issues that may require consideration include:

• A chain of command would need to be established, areas of responsibility wouldhave to be clarified, and callout lists maintained.

• If a prosecution aimed at recovering damages were contemplated the site may beconsidered a Crime Scene which should be secured and appropriately documentswith protocols established for chain of custody of evidence, training of firstresponse team, etc.

• If remediation of damage to grounding sites is desired, rapid response with

funding facilities to contract for this work should be established, etc.

In the case of the current grounding event it is clear that a very large proportion of thedamage was caused by the re-floating effort. This is common to most ship groundings.However, in this case it is frustrating as it appears that much of this impact wasavoidable. Without intent to detract from the fine efforts of the response team whoeffectively recovered this ship, it is respectfully suggested that the damage could havebeen dramatically reduced if longer hausers were used to position the tow boats in deepwater further from the shoaling water. This would have dramatically reduced the scouringof the seafloor and destruction of coral and seagrass communities.

Figure 8: Tugs Attempting to Recover the Ship using Short Tow Lines

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BREAM_BBP 2006-004