MAW01 Cable Risk Assessment Hazard Workshop

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Dorthy Benson
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1 MAW01 Cable Risk Assessment Hazard Workshop Anatec 8 th -9 th November 2018

2 Introduction Ørsted are carrying out a Cable Burial Risk Assessment (CBRA) for the export and inter-array cables associated with the Bay State Wind Offshore Wind Farm. The aim of this workshop is to provide a qualitative assessment of the potential hazards to the cables and get key local stakeholder input. Provide an overview of the approach/process being followed. The findings of this workshop will then be used to inform the quantitative risk assessment. This will include the risk from vessel anchors and any other key hazards identified (e.g. risk from fishing gear). 2

3 Agenda Item Description 1 Welcome and Introductions 2 Project Overview & Workshop Methodology Description 3 Review of Baseline (inc. marine traffic survey data) 4 Discussion of Potential Hazards for each Cable Zone 5 AOB / Close out 3

4 Project Overview 4

5 Guidance BOEM Offshore Electrical Cable Burial for Offshore Wind Farms on the OCS Includes guidance on burial depth vs capacity, special considerations, route selection, navigation risk assessment, cable protection BOEM Offshore Wind Submarine Cable Spacing Guidance DNV/GL RP0360 Subsea Power Cables in Shallow Water. Carbon Trust Guidance for carrying out Cable Burial Risk Assessment COP Guidelines Provides guidance on information requirements for a COP for OCS renewable energy activities on a commercial lease. Nothing directly related to cables 6

6 CBRA Methodology (Carbon Trust) Cable Routeing Desktop study, suitable landfall, minimise cable length Avoid busy shipping areas, anchorage areas, dredging areas Collation of Data Natural Geophysical and geotech surveys, bathymetry, metocean data Anthropogenic AIS data, fishing data, navigational charts, recreational data, UXOs Assessment of Seabed Conditions Seabed features, mobile sediment, soil density Quantitative Risk Assessment (where deemed necessary) Probabilistic assessments of risk to cable from vessel anchors (anchor dragging, emergency anchoring) and from fishing gear Used with anchor and fishing gear penetration models to provide burial recommendations Burial Depth Recommendations 7

7 Hazard Review Process Identify Hazard Agree Residual Level of Risk Identify Causes Identify Mitigations Rank by frequency and consequence 9

8 Cable Interaction Hazards The following list presents potential hazards to the cable : Fishing gear snags on cable Anchored vessel drags anchor onto cable Vessel suffering engine failure anchors onto the cable Vessel inadvertently anchors onto the cable Foundering vessel sinks onto or damages cable Dredging activity damages cable or causes cable(s) to become exposed Military activities damage the cable(s) Recreational activities damage the cable(s) 11

9 Natural Hazards The following list presents potential natural hazards to the cable : Seabed mobility causes cable to become exposed Seabed obstructions/boulders 12

10 3 rd Party Requirements The following issues also require to be considered with respect to cable burial: Bridges Dredged / Maintained Channels Electromagnetic Effects (Navigation and Organisms) Moorings for recreational craft 13

11 Sample Causes The following provides a sample of potential causes to the hazards: High levels of fishing activity Vessels at anchor near cable Bad weather High levels of shipping - emergency/inadvertent anchoring risk Dredging activity Out of date charts Recreational activity Military activity Sand waves / ripples Human error UXOs / seabed obstructions 14

12 Risk Ranking Methodology The definitions presented in the following table will be used to evaluate the frequency of occurrence for each impact: Rank Frequency 1 Negligible 2 Extremely Unlikely 3 Remote 4 Reasonably Probable 5 Frequent 15

13 Risk Ranking Methodology The definitions presented in the following table will be used to evaluate the severity of consequence for each impact: Rank Description People Property Environment Business 1 Negligible No injury No damage No effect No impact 2 Minor Minor injury Minor damage Minor effect Minor impact 3 Moderate Major injury Moderate damage Moderate effect Considerable impact 4 Major Single fatality Major damage Major effect Major national impact 5 Serious Multiple fatalities Extensive damage Extensive effect Major international impact 16

14 Risk Assessment for Burial Recommendations Determination of the consequence (consequence ranking) Determination of acceptable risk criteria (e.g. for a serious consequence the acceptable frequency may be extremely unlikely) Quantification of likelihood for different burial depths Recommend the depth needed to (where feasible). meet the acceptable risk criteria For fishing activity Orsted will consider both Human Safety and economic consequences. For anchor strike the consequences are only considered to be economic. 17

15 Design Burial Depths Interaction Hazards Natural Hazards Third Party Requirements Design Depth 19

16 Cable Burial Design 20

17 Mitigation Measures Mitigation measures to reduce level of risk from hazards could include: Cable re-routeing (e.g. UXO) Cable burial (CBRA Scope) Other cable protection methods, i.e. rock placement/concrete mattress (where burial is not achieved) Inspection and/or maintenance procedures Stakeholder Engagement Fisheries liaison Notice to Mariners Notices to fishermen Monitoring of shipping activity Charting of cable on nautical charts 21

18 Cable Route Zones 22

19 Zone 1 : Mount Hope Bay/Sakonnet River Zone 1 (KP1 to 14) of the export cable route intersects three maintained channels inc. the Mt. Hope Bay main ship channel, Tiverton channel and the Brayton Point Channel. Channels have authorised depths of 35 ft MLLW (USACE). USACE have agreed cable to be buried to 41 ft MLLW (Sept 26 th 2018). The anchored vessels is based on 12 months of AIS from August 2016 July Recreational vessels are only vessel type recorded within close proximity to cable route. 24

20 Zone 1 : Mount Hope Bay/Sakonnet River [Bridge Infrastructure] Stone Bridge Area USACE Navigation Project, 100ft wide, 25ft deep channel. Bridge demolition date not determined, discussions with Rhode Island DOT. Cable burial and scour modelling will consider dynamic area. Known problematic area for cable burial due to construction debris. 25

21 Zone 1 : Mount Hope Bay/Sakonnet River 12 Months AIS (August 2016 July 2017): The figure above represents the vessel type distribution of all AIS tracks intersecting Zone 1 of the export cable. 27

Zone 1 : Mount Hope Bay/Sakonnet River 12 Months AIS (August 2016 July 2017) excluding recreational: The figure above represents the DWT distribution

22 Zone 1 : Mount Hope Bay/Sakonnet River 12 Months AIS (August 2016 July 2017) excluding recreational: The figure above represents the DWT distribution of vessel tracks (exc. recreational) intersecting Zone 1 of the export cable route. Those estimated to be < 500 include fishing vessels and small tugs. 28

23 Zone 1 : Mount Hope Bay/Sakonnet River The deepest vessel draughts recorded intersecting the maintained channels are as follows: Tiverton : 6.7m (22 ft.) from the tug vessel Austin Reinauer Mt. Hope Bay & Brayton Point: 10.5m (34 ft.) from the bulk carrier CSL Spirit As mentioned previously, the authorised depths of the Tiverton & Mt Hope Bay channels is 35 feet. The CSL Spirit was also the deepest draught recorded intersecting Zone 1 of the export cable. 29

24 Zone 1 : Mount Hope Bay/Sakonnet River [Recreational] Borden Light Marina: The figure above represents the length distribution of all recreational tracks intersecting Zone 1 of the export cable route. 30

Zone 1 : Mount Hope Bay/Sakonnet River [Key crossing point] 12 Months AIS (August 2016 July 2017): There were 12 unique commercial vessels (10 cargo and 2 chemical oil tankers) recorded intersecting

25 Zone 1 : Mount Hope Bay/Sakonnet River [Key crossing point] 12 Months AIS (August 2016 July 2017): There were 12 unique commercial vessels (10 cargo and 2 chemical oil tankers) recorded intersecting Zone 1 on 44 occasions. The cargo vessels included general cargo and bulk carriers with destinations set to Fall River, Port Brayton Point, etc. The largest vessel was the 220m (~772 ft) bulk carrier, CSL Tarantau, with a DWT of 71,

Brayton Point between 15 th and 17 th November 2016.

26 Zone 1 : Mount Hope Bay/Sakonnet River [Sample vessels] CSL Tarantau ( MarineTraffic) was recorded intersecting Zone 1 whilst transiting in and out of Brayton Point between 15 th and 17 th November Pandemonium( MarineTraffic) was recorded intersecting Zone 1 on multiple occasions. This vessel is 11m (36 ft.). 32

Zone 1 : Mount Hope Bay/Sakonnet River [VMS obtained from North East Ocean Data Portal] VMS 2015 2016 : Monkfish It is assumed vessels fishing for demersal species (e.g. monkfish) will operate demersal gear.

27 Zone 1 : Mount Hope Bay/Sakonnet River [VMS obtained from North East Ocean Data Portal] VMS : Monkfish It is assumed vessels fishing for demersal species (e.g. monkfish) will operate demersal gear. This type of gear poses the greatest risk to subsea cables as gear is towed along the seabed. The figure opposite presents the density of vessels estimated to be engaged in fishing activities based on vessel speed, however, this does not distinguish between slow moving vessels entering / exiting harbours or ports. A higher density of fishing was recorded at the south of Zone 1. No other demersal fishing operations were recorded on VMS for within proximity to Zone 1 of the export cable. 33

28 Fishing Satellite Data : VMS [VMS obtained from Mid Atlantic Ocean Data Portal] Demersal Trawlers < 65 feet Demersal Trawlers > 65 feet These demersal gears pose the highest risk to subsea cables as gear is towed along the seabed. Fishing gear can penetrate up to 0.3m (12 inches) in soft soil. Carbon Trust recommendation 0.6m (24 inches) burial depth. Boat Dredges 34

29 Anything Missing? Baseline Data Hazards in Zone Causes Mitigation Measures 35

30 Zone 2 : Sakonnet River (KP 14 to 34) There are no main navigational features located within proximity to Zone 2 of the export cable. The anchored vessels are based on 12 months AIS from August 2016 July Only recreational vessels were recorded at anchor within Sakonnet River and thus pose a risk to the cable. Closest vessels were the Roseway & Lady Maryland, anchored approximately 200m east of the cable. 36

31 Zone 2 : Sakonnet River 12 Months AIS (August 2016 July 2017): The figure above represents the vessel type distribution of all AIS tracks intersecting Zone 2 of the export cable. 38

32 Zone 2 : Sakonnet River [Recreational and Fishing] Popular destinations for recreational craft include Pirate Cove Marina, Sakonnet Harbor and Flint Point Ledge off Third Beach where various vessels were recorded at anchor. There was one fishing vessel in particular that made up 86% of the fishing tracks intersecting Zone 2. This was the 25m (82 ft.) vessel Edna May. The Edna May was recorded transiting up/down Sakonnet River to Tiverton. No tracks were estimated to be actively fishing however this vessel operates handlines and polelines, therefore should not pose a risk to the cable. The figure above represents the length distribution of all tracks intersecting Zone 2 of the export cable route. The largest vessel was the passenger vessel Amer Constellation at 82m (269 ft) travelling to Fall River. 39

33 Zone 2 : Sakonnet River [Largest vessel] The largest vessel recorded intersecting Zone 2 was the passenger vessel Amer Constellation (seen opposite) at 82m (269 ft) travelling to Fall River. This was recorded on the 6 th June 40

Zone 2 : Sakonnet River [VMS obtained from North East Ocean Data Portal] VMS 2015 2016 : Monkfish As before, the density presented is estimated to be vessels actively fishing but may include vessels

34 Zone 2 : Sakonnet River [VMS obtained from North East Ocean Data Portal] VMS : Monkfish As before, the density presented is estimated to be vessels actively fishing but may include vessels transiting in and out of harbours in Sakonnet River. As with Zone 1, fishing for Monkfish was recorded along Zone 2 of the export cable route. Higher density was seen to the north of Zone 2 with less activity recorded at the south. 41

35 Anything Missing? Baseline Data Hazards in Zone Causes Mitigation Measures 43

36 Zone 3 : Sakonnet River Buzzards Bay TSS KP 34 to 51. Brenton Point anchorage is approximately 1.5-2nm west of the export cable route. Export cable intersects Buzzards Bay TSS with Narragansett Bay TSS approximately 6-7nm to the west. Recommended vessel route for deep draught vessels and tugs/barges transiting the Rhode Island Sound, Narragansett Bay & Buzzards Bay. 44

Zone 3 : Sakonnet River Buzzards Bay TSS [Anchored Vessels] There was an average of one unique vessel at anchor every two days in this zone (based on unique vessels per day).

37 Zone 3 : Sakonnet River Buzzards Bay TSS [Anchored Vessels] There was an average of one unique vessel at anchor every two days in this zone (based on unique vessels per day). Cargo vessels represented over half (66%) of vessels. The majority of vessels broadcast a destination of Providence. Two vessels were recorded at anchor at locations outwith the designated anchorage area as shown opposite. The pusher tug, Coho, broadcast a destination of St Johns on the 8 th January The bulk carrier, Bulk Beothuk, broadcast a destination of Providence on the 21 st & 22 nd February

38 Zone 3 : Sakonnet River - Buzzards Bay TSS 12 Months AIS (August 2016 July 2017): The figure above represents the main vessel type distribution of all AIS tracks intersecting Zone 3 of the export cable. 47

39 Zone 3 : Sakonnet River - Buzzards Bay TSS [DWT and Length] The figure above represents the DWT distribution of vessel tracks (exc. Recreational & fishing) intersecting Zone 3 of the export cable route. The majority of recreational vessels did not broadcast a destination however some examples recorded include Newport, Nantucket, Martha s Vineyard, Sag Harbour, etc. The figure above represents the length distribution of all recreational tracks intersecting Zone 3 of the export cable route. 48

Zone 3 : Sakonnet River - Buzzards Bay TSS 12 Months AIS (August 2016 July 2017): Majority of commercial tracks (ex tugs/fishing) are associated with the northbound lane of the Narragansett Bay TSS

40 Zone 3 : Sakonnet River - Buzzards Bay TSS 12 Months AIS (August 2016 July 2017): Majority of commercial tracks (ex tugs/fishing) are associated with the northbound lane of the Narragansett Bay TSS to the west of the cable. There was a total of 115 unique crossings of Zone 3 from commercial vessels. Commercial vessels intersecting Zone 3 of the cable range in size from 7,000 DWT to 56,600 DWT. The majority of cargo vessels intersecting Zone 3 were either refrigerated cargo ships or vehicle carriers. These intersecting vessels broadcast destinations such as Boston, St. John, etc. 50

Zone 3 : Sakonnet River - Buzzards Bay TSS 12 Months AIS (August 2016 July 2017): It can be seen from the figure, that there is a high density of tugs utilising the recommended route.

41 Zone 3 : Sakonnet River - Buzzards Bay TSS 12 Months AIS (August 2016 July 2017): It can be seen from the figure, that there is a high density of tugs utilising the recommended route. There are also some vessels utilising the Buzzards Bay TSS to the south of the recommended route. An average of 5 unique tugs per day intersect Zone 3 of the cable route. These are largely pusher tugs involved in tug/tow operations. 51

Zone 3 : Sakonnet River - Buzzards Bay TSS 12 Months AIS (August 2016 July 2017): There were a total of 1,070 unique crossings of Zone 3 by fishing vessels.

42 Zone 3 : Sakonnet River - Buzzards Bay TSS 12 Months AIS (August 2016 July 2017): There were a total of 1,070 unique crossings of Zone 3 by fishing vessels. Majority of vessels appear to be transiting through the study area as opposed to engaged in fishing operations. Wide range of vessels sizes from approximately 40 to 160 ft. (hydraulic dredgers ESS Pride & ESS Pursuit). 52

observed along Zone 3. Higher activity seen to the south.

43 Zone 3 : Sakonnet River - Buzzards Bay TSS [VMS obtained from North East Ocean Data Portal] VMS : Monkfish VMS : Scallop Overall there is a low density of monkfish fishing is observed along Zone 3. Higher activity seen to the south. A small area of scallop dredging takes place at the north of Zone 3 with larger areas of activity seen to the east and west of the cable. 53

44 Anything Missing? Baseline Data Hazards in Zone Causes Mitigation Measures 55

45 Zone 4 : Buzzards Bay TSS Cable End KP 51 to 94) Zone 4 of the export cable route intersects the Narragansett Bay military operating area. In addition, the route intersects a seasonal speed restriction zone (speeds < 10 knots). This applies to vessels over 65 ft. during November to April. 56

46 Zone 4 : Buzzards Bay TSS Cable End 12 Months AIS (August 2016 July 2017): 58

Zone 4 : Buzzards Bay TSS Cable End [Type and Length] The figure above represents the vessel type distribution of all AIS tracks intersecting Zone 4 of the export cable.

47 Zone 4 : Buzzards Bay TSS Cable End [Type and Length] The figure above represents the vessel type distribution of all AIS tracks intersecting Zone 4 of the export cable. The figure above represents the length distribution of all tracks intersecting Zone 4 of the export cable route. The largest vessel was the passenger vessel Europa 2 at 226m (~741 ft) travelling to Oak Bluff. 59

48 Zone 4 : Buzzards Bay TSS Cable End [Largest Vessel] The largest vessel was the passenger vessel Europa 2 at 226m (~741 ft) travelling to Oak Bluff. This vessel has a DWT of 5,285 t. This vessel was recorded intersecting Zone 4 of the export cable on 29 th September

monkfish is carried out along the length of Zone 4 with higher density seen to the north.

49 Zone 4 : Buzzards Bay TSS Cable End [VMS obtained from North East Ocean Data Portal] VMS : Monkfish VMS : Multispecies (Groundfish) Fishing activity for monkfish is carried out along the length of Zone 4 with higher density seen to the north. Density of vessels fishing for groundfish is much lower than monkfish along Zone 4 of the cable. 61

Zone 4 : Buzzards Bay TSS Cable End [VMS obtained from North East Ocean Data Portal] VMS 2015

50 Zone 4 : Buzzards Bay TSS Cable End [VMS obtained from North East Ocean Data Portal] VMS : Scallops VMS : Surfclam & Quahog This fishing is likely to be carried out by scallop or hydraulic dredgers. It can be seen there is a fairly high density of surfclam fishing at the northern end of Zone 4 whilst fishing for scallops is more common to the south. 62

51 Trawl Scars 64

52 Anything Missing? Baseline Data Hazards in Zone Causes Mitigation Measures 65

53 Zone 5 : Inter-array Cables The inter-array cables lie within the Narragansett Bay military operating area. In addition, there is a military transit lane west of the array cables (approx. 20nm). The seasonal speed restriction zone detailed for Zone 4 of the export cable also applies here. 66

54 Zone 5 : Inter-array Cables 12 Months AIS (August 2016 July 2017): The figure above represents the vessel type distribution of all AIS tracks recorded intersecting Zone 5 (array cables). 69

55 Zone 5 : Inter-array Cables 12 Months Fishing (August 2016 July 2017): 12 Months Recreational (August 2016 July 2017): 70

56 Zone 5 : Inter-array Cables [Length and DWT] Vessel Name Type DWT Relentless Offshore 868 Atlantis Research/Survey 1,332 Neil Armstrong Research/Survey 1,472 Caribbean Princess Cruise 8,418 The figure above represents the length distribution of all fishing and recreational tracks intersecting Zone 5. It is noted, no DWT information was available for fishing vessels. The figure above presents the DWT of the passenger and other vessels recorded intersecting Zone 5. It is noted DWT for recreational and fishing vessels is not included due to limited information. 71

Multispecies (Groundfish) Fishing for both monkfish and

57 Zone 5 : Inter-array Cables [VMS obtained from North East Ocean Data Portal] VMS : Monkfish VMS : Multispecies (Groundfish) Fishing for both monkfish and groundfish occurs within proximity to the array cables as seen in the figures above. 72

dredging occurs within proximity to the array cables.

58 Zone 5 : Inter-array Cables [VMS obtained from North East Ocean Data Portal] VMS : Scallops VMS : Surfclam & Quahog Scallop dredging occurs within proximity to the array cables. This type of fishing is the greatest risk to the subsea cables as they are dragged along the seabed. 73

Fishing Satellite Data : 2011-2015 VMS [VMS obtained from Mid Atlantic Ocean

demersal gears pose the highest risk to subsea cables as gear is towed along

59 Fishing Satellite Data : VMS [VMS obtained from Mid Atlantic Ocean Data Portal] Demersal Trawlers < 65 feet Demersal Trawlers > 65 feet These demersal gears pose the highest risk to subsea cables as gear is towed along the seabed. Dredgers can penetrate to depths of 0.2m each operation. Boat Dredges 74

60 Anything Missing? Baseline Data Hazards in Zone Causes Mitigation Measures 75

61 Thank you for attending. 76

62 Other Small Craft Information relating to anchors used for fishing vessels, pilot vessels and Coastguard ships in the area would be highly beneficial as publicly available information is limited. However, if no information can be obtained, the assumptions made for recreational will be used. The length distributions of these vessels within the baseline data are presented below to give an indication of vessel sizes to better inform expert opinion. Vessel Length (ft.) Pilot Fishing Coastguard % % 1% 3% % 2% % 13% 3% % 32% % 17% % % 22% % 2% % % 80

International regulations and guidelines for maritime spatial planning related to safe distances to multiple offshore structures (e.g.

International regulations and guidelines for maritime spatial planning related to safe distances to multiple offshore structures (e.g. wind farms) Introduction This is a summary of the most important international