Enterprise Energy Ireland Corrib Offshore EIS RSK/H/P/P8069/03/04/Appendices Rev01 LIST OF APPENDICES APPENDIX 0.1: RSK ENVIRONMENT LTD – BRIEF SUMMARY OF SERVICES APPENDIX 0.2: ORGANISATIONS CONSULTED DURING THE ENVIRONMENTAL IMPACT ASSESSMENT PROCESS APPENDIX 0.3: KEY CONCERNS RAISED BY THE CONSULTEES APPENDIX 2.1: HISTORICAL ACTIVITY IN THE CORRIB FIELD APPENDIX 4.1: THE HARMONISED OFFSHORE CHEMICAL NOTIFICATION FORMAT (HOCNF) SCHEME APPENDIX 7.1: BIOTOPES IDENTIFIED FROM THE LANDFALL AND CROSSING LOCATIONS APPENDIX 7.2: DESCRIPTIONS OF BIOMAR SITES IN BROADHAVEN BAY APPENDIX 7.3: INTERTIDAL MACROFAUNAL ABUNDANCE FROM THE LANDFALL AND ADJACENT SITES APPENDIX 7.4: SYNOPSES FROM CONSERVATION SITES IN THE BROADHAVEN BAY AREA APPENDIX 7.5: SPECIFICATION FOR BROADHAVEN BAY MONITORING SURVEYS APPENDIX 7.6: CETACEAN SPECIES SIGHTED IN THE VICINITY OF BROADHAVEN BAY APPENDIX 8.1:CORRIB FIELD AND PIPELINE ROUTE SEDIMENT PHYSIO-CHEMICAL DATA APPENDIX 9.1: DISPERSION MODELLING APPENDIX 9.2: DISCHARGES TO WATER APPENDIX 9.3: WATER TREATMENT FLOWCHART APPENDIX 10.1: DESCRIPTION OF ATMOSPHERIC POLLUTANTS APPENDIX 14.1: MARINE ARCHAEOLOGY REPORT, AS SUBMITTED TO DUCHAS
Transcript
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
LIST OF APPENDICES APPENDIX 0.1: RSK ENVIRONMENT LTD – BRIEF SUMMARY OF SERVICES APPENDIX 0.2: ORGANISATIONS CONSULTED DURING THE ENVIRONMENTAL IMPACT
ASSESSMENT PROCESS APPENDIX 0.3: KEY CONCERNS RAISED BY THE CONSULTEES APPENDIX 2.1: HISTORICAL ACTIVITY IN THE CORRIB FIELD APPENDIX 4.1: THE HARMONISED OFFSHORE CHEMICAL NOTIFICATION FORMAT (HOCNF)
SCHEME APPENDIX 7.1: BIOTOPES IDENTIFIED FROM THE LANDFALL AND CROSSING LOCATIONS APPENDIX 7.2: DESCRIPTIONS OF BIOMAR SITES IN BROADHAVEN BAY APPENDIX 7.3: INTERTIDAL MACROFAUNAL ABUNDANCE FROM THE LANDFALL AND
ADJACENT SITES APPENDIX 7.4: SYNOPSES FROM CONSERVATION SITES IN THE BROADHAVEN BAY AREA APPENDIX 7.5: SPECIFICATION FOR BROADHAVEN BAY MONITORING SURVEYS APPENDIX 7.6: CETACEAN SPECIES SIGHTED IN THE VICINITY OF BROADHAVEN BAY APPENDIX 8.1:CORRIB FIELD AND PIPELINE ROUTE SEDIMENT PHYSIO-CHEMICAL DATA APPENDIX 9.1: DISPERSION MODELLING APPENDIX 9.2: DISCHARGES TO WATER APPENDIX 9.3: WATER TREATMENT FLOWCHART APPENDIX 10.1: DESCRIPTION OF ATMOSPHERIC POLLUTANTS APPENDIX 14.1: MARINE ARCHAEOLOGY REPORT, AS SUBMITTED TO DUCHAS
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 0.1: RSK ENVIRONMENT LTD – BRIEF SUMMARY OF SERVICES
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP0.1 - 1
RSK Environment Ltd is an independent consultancy providing specialist support services in the areas of environmental, health and safety management to industry, finance and public sector clients. The core business of the company is based in the oil and gas industry.
RSK was founded in 1989, and has established offices in England, Scotland, the Republic of Ireland, the Isle of Man, Germany and Azerbaijan. RSK’s registered office is in Aberdeen and the Head Office is in Helsby, near Chester.
A large part of RSK’s work can be described under the umbrella of Environmental Impact Assessments. RSK works in all stages of the EIA process, from scoping, liaising with engineers during conceptual and detailed design to report production, and design and implementation of programmes for public dissemination of information. RSK also provide project management during construction and a high level of involvement during reinstatement.
International work is responsible for a large amount of RSK’s revenue. In the past eleven years we have completed work in nearly thirty countries worldwide. RSK has completed more than 200 Environmental Impacts Statements (EIS) during this time, including the following:
• Bellanaboy Terminal EIS, Ireland
• Second Interconnector EIS (subsea route), Ireland and Scotland
• Interconnector EIS (for both landfalls), Ireland and Scotland
• Offshore Oil Development EIS for Esson, Angola
• Drilling and oil production EISs for Elf, Exxon/Mobil, Chevron and BP in the former Soviet Union
• Pipeline route EISs (for oil and gas) from Azerbaijan to Turkey
• Landfall EIS for Elf, Bacton (Norfolk), UK
• Dock re-development EISs, Liverpool, UK
• Incinerator EIS, Isle of Man
• Power Station EISs, Azerbaijan and Morocco
RSK Environment has a wide range of specialists comprising Environmental Scientists and Engineers. RSK Environmental Scientists have disciplines including ecology, biology (including marine), geology, hydrogeology, landscape architecture, archaeology, chemistry and air quality. RSK’s engineering expertise is concentrated in civil, environmental, geological, pipeline and process engineering.
Presented below is a table giving a list of the offshore EIS work that RSK has carried out in the North Sea and associated areas.
Corrib Offshore EIS Enterprise Energy Ireland
APP0.1 - 2 RSK/H/P/P8069/03/04/Appendices Rev01
Technical area
Client Brief description
EIA/EIS BP Exploration Production of EIS for Auburn Field Development.
Venture Production Company
Production of EIS for Pine Development.
Venture Production Company
Production of EIS for Elm Development.
Venture Production Company
Preparation of PON 15s and POPA exemption applications for various drilling projects.
Marathon Oil/Lasmo
Production of EIA report for Larch Field in-field incremental development.
Marathon Oil Production of updated EIS for Brae Field Development.
Marathon Oil Production of EIS for Braemar Field Development.
BHP Petroleum Production of EIS for Keith Field Development.
Elf Exploration Production of EIS for Elgin & Franklin Development
Ranger Oil Production of EIS for Kyle Field Development.
Amoco Production of EIS for Cavendish Field Development.
Confidential Client
Production of EIS for a new Gas Field Development in SNS
Marathon Oil Peer review of EIS for Tranche 37 Well 153/5-A.
Audit/EMS BP Exploration Development and implementation of EMAS & ISO 14001 for SNS Business Unit.
Shell Detailed environmental audit of contracted drilling rig prior to drilling in environmentally sensitive waters off Falkland Islands.
Marathon Oil Offshore audits of Global Marine drilling rig (Glomar Artic III) and onshore contractor management systems.
Kerr-McGee Development of offshore Environmental Management programme for Gryphon FPSO and Murchison Platform.
Transocean Sedco Forex
Development of environmental management systems to cover all U.K. operations. Offshore audits.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP0.1 - 3
Transocean Completion of EMS gap analysis and development of environmental procedures.
Marathon Oil Development and publication of 1997 Environmental Performance Report.
BP Exploration Development and publication of 1997 and 1998/99 EMAS Environmental Statement.
Elf Exploration Completion of offshore (3 platforms and Flotta Oil Terminal) and onshore waste management audits.
Elf Exploration Completion of IPC Audit of Flotta Oil Terminal.
Roemex Development and implementation of ISO 14001.
Diamond Offshore Drilling
Offshore environmental audit of Ocean Nomad Drilling Rig.
Kerr-McGee Completion of audits of drill cuttings disposal companies prior to award of 3 year contract.
Kerr-McGee Pre-commissioning audit of Janice Floating Production Unit.
Atmospherics and IPPC/PPC
BP Exploration Atmospheric emissions monitoring on Schiehallion FPSO.
BP Exploration Atmospheric emissions monitoring on Foinaven FPSO.
BP Exploration Atmospheric emissions monitoring programme – PBLj drilling rig.
Elf Exploration NOx emissions monitoring programme – Piper B Platform.
BP Fugitive emissions and LDAR – Grangemouth Refinery
Shell (Switzerland)
Fugitive emissions and LDAR – Cressier Refinery
Elf Exploration NOx emissions monitoring programme – Flotta Terminal
BP Exploration Fugitive emissions and LDAR – Wytch Farm gathering station.
BP Exploration Provision of offshore and onshore waste management training for SNS personnel.
Corrib Offshore EIS Enterprise Energy Ireland
APP0.1 - 4 RSK/H/P/P8069/03/04/Appendices Rev01
Texaco Production of Asset Development’s Environmental, Heath, Safety and Quality Management System manual.
Marathon Oil Production of Environmental Awareness Training – A Manual for Marathon Employees.
Kerr-McGee Waste management awareness training for rig personnel and Kerr-McGee company representatives.
Amoco Waste management audits and training for Santa Fe (McGellan Rig) Drilling personnel whilst on contract to Amoco.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 0.2: ORGANISATIONS CONSULTED DURING THE ENVIRONMENTAL IMPACT ASSESSMENT PROCESS
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP0.2 - 1
OFFSHORE CONSULTEES Consulted by Letter or Telephone An Taisce (consulted on briefing document) Birdwatch Ireland Coastwatch Europe Dúchas Erris Inshore Fisheries Association Environmental Protection Agency Geological Survey of Ireland Irish Federation of Sea Anglers Irish Lobster Association Irish Salmon Growers Association Irish Shellfish Association Irish Underwater Council Marine Institute Maritime Institute of Ireland Public Exhibitions Pollatomish, McGraths Ballina, Downhill Hotel Killibegs, Fish Ireland Rossport Castlebar Belmullet Meetings Duchas, 26th July Environmental Protection Agency, 5th October
APPENDIX 0.3: KEY CONCERNS RAISED BY THE CONSULTEES
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP0.3 - 1
Consultees Key Concerns Addressed in
Section • Provide figure showing relative size of project to
the land. 1.0
• Reference made to reviewed policies and plans also current policy on coastal zone management.
5.0
• Further information required on socio econ baseline.
6.0
• Socio-economic impact of decommissioning needs to be considered.
6.0
• More information required on sites proposed for conservation designation.
7.0
• Discussion of impact on SAC. 7.0 • Summary of likely environmental consequences
and implications. Show construction will not affect the environment.
16.0
• Significant effects away from immediate areas of construction and operation.
17.0
• List any species recorded which are listed under the habitats directive
7.0
• Details on blasting need to be submitted to MCC. 3.0/11.0 • Noise limits 11.0 • Landfall restoration plan submitted to MCC and
PAD for approval. 12.0
• Climate change – further clarification on meteorology and oceanography.
13.0
• Protection of Archaeological ‘chance’ finds procedure to be submitted to Duchas and PAD.
14.0
• Submit waste management plan to appropriate planning authority for approval.
15.0
• Hydrotest discharge water plan must be submitted to PAD.
3.0/15.0/16.0
• Drilling operations and various operational monitoring requirements.
18.0
• Field facilities and pipeline. Visual inspections. 2.0/16.0 • Detailed consideration given to uncontrolled
events outside production process. 16.0
• Distribution of habitats – distribution of species. 7.0 • Pipeline decommissioning. 3.0 • Blasting and decommissioning. 11.0/3.0 • Outfall discharges 9.0 • Noise and vibration issues at the landfall. 3.0/11.0 • Assessment of impacts on fishing activity,
cumulative effects on fisheries. 6.0/17.0
• Other planned developments in the area. 17.0 • Cumulative impacts of outfall discharge. 17.0 • Monitor effectiveness of proposed environmental
management systems over operational life. 18.0
Department of Marine and Natural Resources Petroleum Affairs Division (PAD)
• Submission of environmental reports 18.0 Marine Institute • EIS need to address issues arising from the
Dumping at Sea Act 1996. 1.0
Chief State Solicitors
• Show proposed development will not adversely affect the SPA and SAC.
7.0
Corrib Offshore EIS Enterprise Energy Ireland
APP0.3 - 2 RSK/H/P/P8069/03/04/Appendices Rev01
Consultees Key Concerns Addressed in Section
• Assess activities within and outside designated area that could indirectly affect SPA.
7.0/17.0 Office
• Discharge of drilling fluids. 7.0 • Spillage of oil during drilling. 7.0 • Disturbance to seabed and current patterns from
facilities and pipeline installation. 7.0/8.0/9.0
• Flaring during well testing 10.0 • Acoustic energy and acoustic energy releases. 11.0/7.0 • Supply vessels and aircraft (noise) 11.0 • Seismic work on redefinition of reservoir. Appendix 2.1 • Emissions from vessels - Global warming. 10.0/13.0/15.0 • Release of natural gas from subsea structures –
Global warming. 13.0
• Discharges containing hazardous substances. 15.0 • Methods of cuttings disposal. 3.0 • Chemical discharge during drilling and
cementing. Appendix 2.1
• Produced water and deck drainage. 9.0 • Discharge of produced water. 9.0 • Impacts if trawling across pipeline is not allowed. 6.0 • Inshore fishermen concerned with water quality. 9.0
An Taisce
• Exclusion zones 15.0 • Discharge of process effluent into the estuary. 9.0 • Blasting adjacent to aquatic zones. 7.0/11.0
Central Fisheries Board
• Exact location of outfall 9.0/15.0 Marine Licensing Vetting Committee
• Economic and social issues need to be resolved. 6.0
• Impact on local linguistic and cultural heritage. Also impact on tourism and recreation.
6.0
• Effect on fishermen, angling and diving tourism. 6.0 • Effect on cetaceans 7.0 • Discharge of methanol into Broadhaven Bay 9.0 • Traffic movements, safety, school runs and road
conditions. 15.0
• Environmental disaster management and minimization of environmental damage.
16.0/18.0
• Baseline study of heavy metals. 17.0/18.0 • Vehicle movements 15.0
Local Community
• Impacts to active season of wading birds, wildfowl and corncrake.
7.0
Dave Dendy • Permanent landscape impacts 2.0/3.0/12.0 • Deposition of spoil in SAC and SPA. 3.0/7.0 • No sand or mud to be removed. 7.0 • Presence of otters 7.0 • Impacts to little tern when constructing landfall 7.0
Duchas
• Impacts to corncrake 7.0 • Reinstatement of soft shore and sand dunes at
Dooncarton. 3.0/7.0
• Impact of construction activities within an SPA 7.0 • Assessment of landfall alternatives 4.0 • Impact of past drilling operations 7.0/Appendix 2.1
Bird Watch Ireland
• Lack of detailed surveys 7.0
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP0.3 - 3
Consultees Key Concerns Addressed in Section
• Impact on seabed habitats 7.0/Appendix 2.1 • Bioaccumulation of metals in offshore species. 7.0/9.0/17.0/Appendix
2.1 • No data has been presented from seismic surveys
in 1997 Appendix 2.1
Dr Alex Rogers
• Disturbance to cetaceans. 7.0/11.0 • Impact monitoring. 18.0 • Effect of pipe laying, drilling, the use of sonar
and noise and vibrations from the site on cetaceans.
7.0
• Oil spills contingencies. 18.0 • Monitoring of cetacean activity post construction
• Access to site for workers and products etc. 15.0
Mayo County Council
• Landfall activities – habitat and bird disturbance, effects on little tern.
7.0/16.0
PAD, Local Community, Porturlin shellfish and Dave Dendy
• Effects of discharge on Broadhaven Bay; seaweed, shellfish and other marine species.
7.0/9.0
AWABI and Local Community
• Further research into tidal movements. 6.0/9.0/15.0
Central Fisheries Board and Porturlin shellfish
• Fishing interests within and close to construction area should be informed prior to construction.
18.0
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 2.1: HISTORICAL ACTIVITY IN THE CORRIB FIELD
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 1
Figure App 2.1-1: Schematic of marine seismic survey............................................................ 3
Figure App 2.1-2: Schematic representation of a typical airgun........................................... 4
Figure App 2.1-3: The MV Western Monarch............................................................................. 6
Table App 2.1-1: Summary Characteristics of the 1994 2D Seismic Survey .......................... 5
Table App 2.1-2: Summary Characteristics of the 1997 3D Seismic Survey ........................... 5
Table App 2.1-3: Impacts on benthic organisms from seismic airgun surveys ..................... 7
Table App 2.1-4: Effects on eggs and larvae caused by seismic airguns ............................ 8
Table App 2.1-5: Effects on adult fish caused by seismic airguns ........................................10
Table App 2.1-6: General key threshold values for behavioural effects in fish ..................11
Table App 2.1-7: Overview of historical drilling activity in the Corrib Field ..........................17
Table App 2.1-8: Summary of the surveys carried out in the Corrib Field ...........................18
Table App 2.1-9: Estimated Routine Atmospheric Emissions per Well...................................19
Table App 2.1-10: Estimated Emissions from Production Well Tests .......................................19
Table App 2.1-11: Summary of Historical Drilling Activity in the Corrib Field.......................21
Table App 2.1-12: Reported Tonnage of Mud Chemical Discharges from Corrib Field Wells ...........................................................................................................................22
Table App 2.1-14: Recorded Waste Arisings transported for Onshore Disposal ................24
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 2 RSK/H/P/P8069/03/04/Appendices Rev01
HISTORICAL ACTIVITY IN THE CORRIB FIELD, A RETROSPECTIVE ANALYSIS Summary of Historical Activity in the Corrib Field
The Corrib Field is located on the Irish Continental Shelf off north-west Ireland, County Mayo. As such, under the 1958 Geneva Convention on the Continental Shelf, Ireland has the exclusive sovereign rights over the hydrocarbon resources.
Enterprise, Saga, Statoil and Marathon initially held the licences for blocks 18/20 and 18/25. However, following the purchase of Saga by Norsk Hydro, Saga sold its interest in the Corrib licences to Statoil. The licence status is now Enterprise Energy Ireland Ltd (45%), Statoil Exploration (Ireland) Limited (36.5%) and Marathon International Petroleum Hibernia Limited (18.5%).
Exploration activities have been taking place in the Corrib Field since 1994. This Appendix provides details of these activities, including the seismic survey programme and the exploration and appraisal drilling programme. The Appendix then goes on to discuss the emissions (to air, water and solid waste) and the possible environmental impacts of these activities and discharges.
Seismic Survey Programme
Enterprise carried out programmes of seismic surveys within the Corrib Field area in 1994 and 1997. It should be noted that Enterprise do not intend to carry out any further seismic exploration within this area; therefore the following assessments of seismic impacts are purely a retrospective assessment of activities already undertaken.
Overview of Seismic Surveys
Seismic surveys are carried out in the seas to study the layers of rock lying beneath the earth’s surface and to determine where oil and gas deposits may be located. Energy pulses in the form of moderate level, low frequency sound sources are discharged into the water column. These pulses travel through the geological strata and are reflected from the boundaries of these strata. They are subsequently recorded by receivers near the water surface (Figure App 2.1-1). The depths of the reflecting layers are calculated from the time taken between the sound generation and the received reflected signal being detected by the receiver, and the resulting information can be analysed to determine the underlying geological structure.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 3
Water
Acoustic Source
Hydrophone Receiver
Recording System
Figure App 2.1-1: Schematic of marine seismic survey
Previously, and as late as the 1960s in some places, the most commonly used energy source for seismic surveys was chemical explosives. However, these are now rarely used for offshore surveys, in part as a consequence of the negative impact on the environment associated with their use. They have largely been superseded by other sources such as water guns, gas detonators, spark generators and the more common airguns.
Airguns are operated either singly or in arrays. Single airgun sources are used only for shallow water surveys. Rig site surveys use a single, small array. Deep water surveys, such as those carried out in the Corrib Field, require arrays which are comprised of several sub-arrays of airguns.
The seismic airgun is an impulsive underwater transducer which produces moderate energy level sound at low frequencies (Figure App 2.1-2). In operation, air at high pressure (1,900 psi) is supplied continuously to the airgun. This forces the piston downwards. The chambers fill with compressed air while the piston remains in the closed position. When triggered, the solenoid valve opens and the piston is forced upwards. The compressed air in the lower chamber flows rapidly through the ports, pushing air away from the airgun and creating a pressure wave. This sudden release of air resembles a small explosion, and it generates energy which radiates into the earth below the sea floor.
The seismic signal, reflected by boundaries in the subsurface geology, is received by hydrophones (pressure sensors) carried in streamer cables. These consist of tubular sections, containing the receiver phones, and electrical conductors which carry the signals. The cable sections are connected together with electronic modules where the signals from the
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 4 RSK/H/P/P8069/03/04/Appendices Rev01
phones are digitized and put onto an optical carrier for returning to the recording system onboard the vessel.
Streamer cables are filled with electrical insulating fluid, which has a specific gravity less than one to make the overall streamer neutrally buoyant. Although historically organic compounds were used, more recently purely synthetic non-water based materials have replaced these.
Solenoid Valve
High Pressure
Air
High Pressure
Air
Triggering Piston
Port Port
Firing Piston
High Pressure Air
DISCHARGE RECHARGE
SOUND PULSE EMITTED
Figure App 2.1-2: Schematic representation of a typical airgun
There are different types of seismic survey. 2D surveys are, by comparison to 3D, fairly basic, inexpensive and relatively simplistic in their use of seismic exploration methods. 3D surveying is a much more complex and accurate method of seismic surveying which involves greater investment and more sophisticated equipment. Until the beginning of the 1990’s, 2D work predominated as the primary tool in oil and gas exploration. 3D tends now to be used for the more detailed phases of the work. For both 2D and 3D surveys, the seismic vessel towing the survey equipment is required to sail along predetermined paths.
Outline of the Corrib Field Seismic Survey Programme
Enterprise carried out a programme of seismic acquisition in connection with the exploration and appraisal of the Corrib Field. In August 1994 a 2D survey was carried out by Geoteam using the MV Nalivkin. The characteristics of this survey are summarised in Table App 2.1-1.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 5
Table App 2.1-1: Summary Characteristics of the 1994 2D Seismic Survey
Survey Parameter Details No of seismic lines 70
Total no. km covered 1208 Line orientation 275 or 45 degrees Energy source Airguns
Cable Single Cable length 3000 m Cable depth 7.8 m
This 2D programme was followed by a more extensive 3D survey in 1997 carried out in two phases by Western Geophysical using the MV Western Monarch (Figure App 2.1-3). Phase 1 took place between 23rd June and 24th July 1997 and Phase 2 between 11th August and 24th August 1997. Table App 2.1-2 summarises the survey parameters.
Table App 2.1-2: Summary Characteristics of the 1997 3D Seismic Survey Parameter Details
Phase 1 Phase 2 General
Area of coverage (full fold area) 400 200 km2 Number of data acquisition lines 72 32
Average line length 19.6 km 19.6 km Line orientation 298 degrees
Source Source volume:
Combined chamber volume for each array Combined chamber volume for each subarray
4350 cu. inch 1450 cu. inch
Nominal operating pressure 2000 psi No. of active guns 72
Source interval 25 m Shot interval 25 m Source depth 10 ± 1 m
Streamers Number of streamers 6 8
Streamer spacing 100 m Streamer length 4000 m
Streamer deployment depth 10 ± 1 m
Enterprise do not intend to carry out any further seismic exploration within the Corrib Field.
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 6 RSK/H/P/P8069/03/04/Appendices Rev01
Figure App 2.1-3: The MV Western Monarch
Environmental Description
The background data used to determine the impacts of the seismic survey programme is taken from Chapter 7 of the EIS.
Impacts of the Seismic Survey Programme
The seismic survey operations described above would have resulted in emissions of combustion gases, and liquid and solid wastes. Air emissions would have been in the same order as those for a large fishing vessel, and are therefore not anticipated to have resulted in significant impacts. The only waste streams discharged from the seismic vessels during the survey operations were black and grey waters and food waste as permitted under the MARPOL international shipping agreement. Such discharges have the potential to impact plankton and fish in the surface waters over a localised area; however, the impact would be no greater than that associated with any other marine vessel. Any solid wastes were returned to shore for disposal.
The remainder of the discussion on impacts from seismic surveys relates to the operation of the seismic source – i.e. the airgun array.
Impact on Benthos
The findings of several key studies on the assessment of the potential impact of seismic operations on specific macrobenthic organisms are summarised in Table App 2.1-3.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 7
Table App 2.1-3: Impacts on benthic organisms from seismic airgun surveys
Author Species Experimental work Observations Kosheleva (1992)
Macro-benthic community
Barents Sea. Airgun array volume of 80-180 cubic inches. Source level 220-240 dB re1µPa @ 1 m.
No effect on caged macrobenthos at distances greater than 1 m from seismic source.
Webb & Kempf, 1998.
Brown shrimp Crangon crangon
Wadden Sea. Array of 15 airguns, total volume 480 cubic inches at 2,000 psi. Source level 190 dB re1µPa @ 1m. Water depth 2 m.
Observations during the survey showed no mortality of shrimp and no evidence of reduced catch rates. Impact limited due to lack of gas voids and rigid exoskeleton.
La Bella et al., 1996.
Venerid clam Paphia aurea
Central Adriatic Sea. Array of 16 airguns, total volume 2,500 cubic inches at 2,000 psi. Intensity 210 dB/Hz re 1 µPa @ 1m. Water depth 15 m.
Sampled using a commercial clam dredge. Same density estimates were obtained from the dredge samples before and after the seismic acquisition with no evidence of clam mortalities.
The 1994 and 1997 Corrib seismic surveys were undertaken in water depths of approximately 350 m. No bubble pulse train effects, resulting in re-suspension of superficial sediments into the water column, would have been observed due to the deep water of the Corrib Field. It is generally accepted that no significant disturbance to the seabed or impacts to the associated benthic community from airgun operations are observed in water depths greater than 50 m.
Impact on Plankton and Fish Recruitment
Planktonic organisms can be divided into two broad divisions, the phytoplankton (photosynthetic plankton largely capable of independent growth, mostly unicellular algae) and zooplankton (heterotrophic organisms which are dependent on other organisms as a food source).
The phytoplankton forms the major basis for the marine food chain. Phytoplankton species are characterized by relatively resistant unicellular structures and short generation times, ranging from a few doublings per day for the faster growing species, to one doubling every week to ten days for the slower growing species (Harris, 1986). Their natural population dynamics are further characterized by high mortality rates and marked patterns of seasonal and annual fluctuations in abundance.
Zooplanktonic organisms are multicellular, and have organs and tissues which are more sensitive, at close proximity to the airgun, to pressure waves created by the seismic source. The degree of exposure of zooplankton to the seismic airgun array is dependent upon abundance, spatial distribution, seasonal timing and the duration of the seismic survey. As for phytoplankton, natural population dynamics for zooplankton are characterized by short generation times and high natural mortality rates,
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 8 RSK/H/P/P8069/03/04/Appendices Rev01
with some species having natural mortality rates as high as 99.999% per generation (McCauley, 1994).
It is the meroplankton component of the zooplankton (planktonic organisms which only spend part of their life in the plankton, such as the eggs and larvae of fish and invertebrates) that has been the focus of studies reported in the literature, as the fitness of these stages of the fish life cycle is considered to be an important factor in determining adult fish population structure (Doherty & Williams, 1988).
The findings of several key studies undertaken to assess the extent and type of injuries to eggs and larvae exposed to airguns are summarised in Table App 2.1-4.
Table App 2.1-4: Effects on eggs and larvae caused by seismic airguns Author Experimental
work Results and Conclusions
Kosheleva, 1992 Source level 220 dB re1µPa @ 1m.
Eggs and larvae of plaice died at 1 m distance, but uninjured at 2 m.
Matishov, 1992 Source level 250 dB re1µPa @ 1m.
Damage to 5 day old cod at distances of 1 m. Delamination of the retina.
Dalen & Knutsen, 1987
Source level 222 dB re1µPa @ 1m.
No mortality of cod eggs and larvae (small airgun Bolt 600B).
Holliday et al. 1987 Source level 223 dB re1µPa @ 1m.
Damage to eggs and larvae of anchovy at distances up to 2 m. Possible mortality of larvae at 2 m.
Kostyvchenko, 1973 Source level 230 dB re1µPa @ 1m.
Injuries to eggs of red mullet, anchovy and various other species, within a radius of 5 m. Damage included deformation of the outer egg membrane, spiral curling of the embryo, displacement if the embryo and damage to the vitelline membrane.
Source: Adapted from DNV, 1993
The findings of these studies indicate that injuries and mortality to eggs and larvae are highest at close range, within 2 m of the source, and decrease rapidly with distance from the gun. Outside a range of 5 m, no effects are demonstrated (Kostychenko, 1973).
In an attempt to update this data and determine the internal injuries that eggs, larvae and fry might exhibit, studies on the impacts of airguns on the early life stages of fish were continued at Havforskningsinstituttet (the Norwegian Institute of Marine Research ) during 1992 and 1995.
The findings of these investigations confirmed those of previous experimental work. Mortality effects for fish eggs were demonstrated up to a distance of 5 m from the airgun source. Experiments investigating later life stages such as larvae, post-larvae and fry revealed that relatively high mortality rates were found in plaice with 10 - 20% mortality at a distance of 2 m, and pronounced mortality was also shown in cod at 5 m. Increased
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 9
mortality rates at the post larval stage were also demonstrated at 1 - 2 m from the seismic source (Dalen et al., 1996).
Other observed effects included changes in the buoyancy of organisms which influences their ability to avoid predators, and the condition of the larvae which in turn affects their ability to survive (Dalen et al., 1996).
This experimental data indicates that seismic surveys only cause direct damage to eggs and larvae within a very limited area around the seismic source that varies depending on species (up to 5 m from the source). As a result of the findings of this work, the Norwegian Authorities made the decision not to impose restrictions on survey work on the basis of damage to fish eggs, larvae and fry (Webb & Kempf, 1998). The findings indicated that the effect of seismic surveys at the population level, in terms of species recruitment, is not statistically significant (Dalen et al., 1996) as ichthyoplankton species are generally widely distributed, and recovery, in terms of both abundance and diversity, is usually rapid in response to localised impacts. McCauley (1994) demonstrated that the fraction of the meroplankton affected during an airgun survey is much less than 1% of the natural mortality. In addition, stochastic (chance) events may also grossly override any deterministic processes involved in larval replenishment. Hence events such as storms, and plankton drift may completely mask any effects from seismic surveys (McCauley, 1994).
The 1994 and 1997 seismic surveys were undertaken between June and August, coinciding with the spawning period of pelagic mackerel (March to June) but outside the spawning period for demersal fish species in the area (late winter to spring). It should be noted, however, that demersal fish larvae may still have been present within the plankton during the seismic survey period as it remains in the surface water for approximately 6 months.
The above studies show, however, that due to the naturally high mortality rates for planktonic organisms, the direct mortality effects of the seismic surveys would have lead to neither statistically significant nor measurable impacts on the plankton populations or fish recruitment at population level.
Impact on Adult Fish
Several studies have been performed to determine whether seismic airguns cause damage to adult fish. Field experiments have been conducted using penned fish held at different distances from a seismic source. The findings of some of the key studies are shown in Table App 2.1-5.
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 10 RSK/H/P/P8069/03/04/Appendices Rev01
Table App 2.1-5: Effects on adult fish caused by seismic airguns Author Experimental work Results and Conclusions La Bella et al. (1996)
Captive fish in cages at 12 m depth. Airgun array 210 dB/Hz re1µPa @ 1m. Seismic vessel passed at a minimum of 150 m.
200 Sea Bass. Behavioural response to the approach of the sound source, but no lethal event was recorded on captive sea-bass immediately after the seismic shooting. The cage was recovered after 6 hours, no evidence of traumatic effects on fish skeleton structure.
Matishov (1992)
Single airgun. 226 dB re1µPa @ 1m.
Transient stunning: cod died within 48 hours owing to internal injuries.
Kosheleva (1992)
Single airguns and arrays. 1,000 - 3,000 cubic inches Source level 220 - 240 dB re1µPa @ 1m.
50% of Barents Sea cod, subject to airgun emissions, with peak sound pressure levels estimated in the range 220 - 240 dB, suffered damage to blood cells, internal bleeding and eye injuries when in the immediate vicinity (i.e. within 0.5 m) of the firing airgun or array.
Falk & Lawrence (1973)
Single airgun 4916 cm3 Source level 230 dB re 1µPa @ 1m.
Caged whitefish exposed to a single large airgun resulted in several fish with swimbladder damage.
The findings of the experimental work reviewed indicate general threshold levels for potential pathological and lethal effects in fish. The findings further indicate that beyond a range of 0.5 - 1 m from the airguns, no fish are killed. Internal injuries appear to occur in fish at received sound pressure levels of 220 dB, which only occur very close to the source, and general auditory damage from 180 dB (Turnpenny & Nedwell, 1994). Gausland (1992) also reported that fish killed within a distance of 0.5 m of airguns had ruptured swimbladders. The pressure pulse generated by airguns is considered to be the most important factor leading to tissue damage in fish.
Under natural conditions, fish detect the sound of airguns at long distances, and healthy adult fish will exhibit avoidance behaviour, moving away from the sound source. The fish sense both the strength and direction of the sound produced by airguns as the frequency spectrum, 10 - 200 Hz, coincides with the most sensitive region of fish hearing, 20 - 700 Hz. The hearing capabilities of fish indicate that the sound of a full-scale airgun array may be heard at a distance of more than 100 km (Dalen et al., 1996). The type of behavioural response that may be elicited in response to a range of source levels is summarised in Table App 2.1-6.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 11
Table App 2.1-6: General key threshold values for behavioural effects in fish
Source level Behavioral effect Range from airgun for these effects to be exhibited
160 dB re 1µPa Subtle changes 2.1 - 12 km
180 dB re 1µPa Alarm response, e.g. tight milling
630 - 2,000 m
200 - 205 dB re 1µPa
Startle response, e.g. attempts to flee
100 - 316 m
Source: Based on McCauley, 1994
Fish avoidance capacity is largely determined by their size, and it is expected on the basis of established knowledge of swimming ability, that most fish bigger than 30 - 50 mm will swim away and keep a safe distance from the passing seismic source. Hence injuries caused by seismic survey activity would be expected to be restricted to the juvenile stages (i.e. fish less than 50 mm in length).
Adult fish likely to have been present during the seismic surveys of the Corrib Field are described in Section 7 of the main EIS. From this, it can be seen that, during the 1994 and 1997 seismic surveys (conducted between June and August) the majority of commercial pelagic fish species (e.g. mackerel and horse mackerel) would still have been in the vicinity of the Corrib Field following spawning off the west coast of Ireland. In addition, the following demersal fish species may have been present haddock, cod, angler, megrim, saithe and sole. Of the species mentioned, mackerel, angler, megrim and sole do not have swimbladders, and all but the mackerel and horse mackerel are found close to the seabed, more than 300 m from the seismic source, therefore the potential damage to these species from seismic activities in the Corrib Field was low. It should also be noted that adult fish normally exhibit avoidance behaviour in response to seismic survey activities thus effectively evading potential damage.
At greater risk from airgun operations are juvenile fish. At close range (less than 5 m) of a firing airgun, mortality may be observed as juvenile fish, which are less than 50 mm in length, are unable to swim away from the seismic source. It should be noted, however, that juveniles tend to be concentrated in the shallow shelf areas rather than the offshore areas in the vicinity of the Corrib Field.
Natural mortality rates for juvenile fish are high, therefore it is considered that the direct mortality effects of the seismic surveys would have lead to neither statistically significant nor measurable impacts to fish recruitment at the population level.
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 12 RSK/H/P/P8069/03/04/Appendices Rev01
Impact on Seabirds
Offshore bird species present in the vicinity of the Corrib Field are listed in Section 7 of the main EIS. During the 1994 and 1997 surveys (June-August period) the following species are likely to have been present; gannet, gulls, shearwaters, petrels, storm petrels and auks.
It should be noted that acoustic damage to birds could only have been experienced if they were diving in close proximity to the airgun array (i.e. within 5 m of the array). However, as the array is towed directly behind the survey vessel there would effectively have been a bird free corridor where the vessel disturbed any birds present. Although some alarm may have been caused to birds as the array passed, they would already have been beyond any harmful range (Macduff-Duncan & Davies, 1995). It is not considered likely that birds would have been in the water close to the airgun array once it was operating. In 20 years of seismic exploration in the North Sea no reports of seabird injuries or deaths due to seismic activity are known to have been reported (Dave Simmons, pers comm.).
Impact on Marine Mammals
During the last thirty years, seismic survey operations have been conducted extensively in the seas around Northern Europe. The introduction of regular loud noises into the marine environment over extended periods of time has led to concerns that marine mammals at short distances might be physically damaged, and at greater distances be disturbed in such a way as to interfere with their daily activities such as communication, or be displaced from preferred feeding or breeding areas.
Impact on Cetaceans
The dominant frequencies of seismic sound sources overlap directly with those used by baleen whales for obtaining information about their environment and communicating with one other. Information on the behavioural effects of seismic testing is limited almost exclusively to two baleen species; the bowhead whale in the Beaufort Sea and the grey whale off California. However, the findings are broadly similar, with avoidance responses being elicited particularly from received sound levels of 160-170 dB. This compares closely with the sound levels eliciting an avoidance-response in a variety of fish species (Evans & Nice, 1996).
Sightings surveys show that sperm whales were displaced to a distance of 60 km from an area in the Gulf of Mexico, where seismic surveys were taking place (Mate et al., 1994). Sperm whales were also found to stop vocalising in response to relatively weak seismic pulses from a ship hundreds of kilometres away (Bowles et al., 1994). Studies by Rankin and Evans (1998) in the Northern Gulf of Mexico indicate that seismic exploration has a negative impact on aspects of communication and orientation behaviour of sperm whales, but no effects on the distribution of other odontocetes.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 13
In a series of studies using a 4000 cubic inch air-gun array, 10% of grey whales showed avoidance to received broad-band levels of 164dB re1µPa, 50% showed an avoidance reaction at 170dB re1µPa, and 90% at 180dB re1µPa. Whales were seen to move into the shallow surf zone and into sound shadows of rocks (Malme et al., 1983; 1984 cited in Richardson et al., 1995).
Koski and Johnson (1987 - in Richardson et al., 1995) noted that bowhead whales swam rapidly away from a seismic vessel at a distance of 24 km. Ljungblad et al. (1988) observed initial behavioural changes of bowheads more than 8 km away, at received noise levels of 142-157dB re1µPa. Richardson et al. (1985) found subtle alterations in surfacing, respiration and dive cycles in response to seismic vessels, indicating that the absence of a conspicuous response does not necessarily prove that an animal is unaffected. Richardson et al. (1986) observed bowhead whales engaging in normal activities as close as 6km to the vessels, where estimated received levels were 158dB re1µPa.
Direct physical damage to the hearing of whales has been implicated recently from post-mortem examination of humpback whales exposed to loud noises such as underwater blasting and dredging (Lien et al., 1993). However, according to Evans & Nice (1996), in the case of seismic airguns this is only likely to be a problem at very short distances, in the order of low hundreds of metres (or received sound levels of 220 dB). As mentioned above this is unlikely to occur due to the avoidance reaction exhibited by the whales.
The hearing of odontocetes (porpoises, dolphins and toothed whales) is most sensitive over the frequency range 10-150 kHz. As this is outside the peak energy range of seimic airguns one might predict that they would be less susceptible to seismic sound than baleen whales. However, airgun arrays also produce significant sound at frequencies ranging from 1-20 kHz, which overlap the hearing range of odontocetes (Goold & Fish, 1999).
Acoustic and visual surveys of odontocetes in the Irish Sea showed temporary displacement of small cetacean populations (Evans & Nice, 1996). Goold & Fish (1999) also observed this avoidance reaction in surveys undertaken in the southern Irish/Celtic Sea, where common dolphins preferred to be at least 1 km away from the seismic source. They also noted that the seismic emissions appeared to be clearly audible to dolphins over a distance of 8 km.
In addition to the direct effects of seismic impulses upon marine mammals, seismic testing can also adversely affect cetaceans in an indirect manner by having an impact upon their potential prey species. This can occur in a number of ways: the first and most frequent is the change in distribution of fish species under the influence of seismic shooting (Dalen & Raknes, 1985), since they are often scared away from the area under influence. It has also been demonstrated that seismic sound pulses may change the shoaling behaviour of fish (Turnpenny & Nedwell, 1994). Norwegian studies of the effects of seismic activities upon fish distribution have shown spatial
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 14 RSK/H/P/P8069/03/04/Appendices Rev01
displacement of fish over an area of 5,500 km2, extending for a period of at least 5 days. This could have an indirect effect upon odontocetes which depend upon fish for food, displacing them from favoured areas or making them expend more energy to re-locate a food source than would otherwise be the case (Engas et al., 1993).
Baleen and Odontocete species recorded off Northwest Mayo are listed in Table 7.3. It is unlikely that these species would have been physically damaged by the seismic survey operations, as they would have exhibited avoidance behaviour to the seismic source. However, as described above, this behavioural response has the potential to disrupt communication, feeding and breeding patterns. However, the short term nature of the seismic surveys (1 month in 1994, 1 month in June/July 1997 and two weeks in August 1997) is unlikely to have had a significant impact on the cetacean populations in the area and the moving seismic source would not have provided a restriction of access to a preferred habitat for any great length of time.
Impact on Seals
The extent of physical damage to seals from seismic survey is likely to be very limited as they generally exhibit avoidance behaviour, in the same way as fish, to seismic noise. Available data (McCauley, 1994) suggests that marine mammals avoid seismic vessels within a 1 - 3 km range (i.e. when received impulse levels reach 160 - 170 dB re 1 µPa). Seals are therefore unlikely to be in the immediate vicinity once seismic operations have begun.
There have been few studies on the reactions of seals to seismic survey noise. Recently, however, detailed observations of behavioural and physiological responses of harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus) have been reported by Thompson et al. (1998). These researchers conducted one hour playbacks with small airguns to individual seals that had been fitted with telemetry packs. The telemetry packs allowed the seals’ movements, dive behaviour and swim speeds to be monitored and provided detailed data on the animals’ responses to seismic pulses.
Harbour seals showed short term startle reactions, evidenced by a sudden profound drop in heart rate (bradycardia) and in six out of eight trials showed avoidance reactions to simulated seismic surveys using a three times 30 cubic inch airgun array and a single 20 cubic inch (0.33 litre) gun at ranges of 2 km. In four cases, the seals reverted to the undisturbed foraging pattern within minutes of the end of firing. In two cases the animal swam to a haulout site apparently in response to the guns. Grey seals also showed avoidance reactions, moving away from the source and increasing their swim speed. All test animals continued to, or returned to, forage in the areas where they were exposed to airgun sounds (Thompson et al., 1998).
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 15
The indirect behavioural responses of seals are perhaps of more concern than direct physical damage, as they could potentially result in lowered survival or reproductive success (Evans & Nice, 1996). Behavioural changes such as disruption of normal feeding, breeding and migration patterns are all potential effects brought about by seismic survey. These effects are a consequence of the avoidance behaviour of seals to seismic surveys and the displacement of seal populations due to reduced prey availability and the need to search for a new food source (Evans & Nice, 1996).
As the Corrib seismic survey programme was undertaken approximately 70 km offshore, the majority of common (Phoca vitulina) and grey (Halichoerus grypus) seals in the area would have be unaffected by the operations due to the fact that they would have been concentrated in the coastal areas. However, there is evidence that some seal species, and particularly grey seals, feed in a variety of continental shelf habitats and relatively far offshore in some cases (CRC pers. comm.). These individuals are likely to have shown avoidance reactions to the seismic surveys moving away from the seismic source and increasing their swim speed.
However, the short term nature of the seismic surveys, is unlikely to have had a significant impact on the seal populations in the area and the moving seismic source would not have provided a restriction of access to preferred feeding habitats for any great length of time. As noted by Thompson et al., 1998, it is highly likely that the seals returned to their foraging areas following cessation of seismic operations.
Mitigation Measures for the Seismic Survey Programmes
The main mitigation methods associated with Corrib seismic survey programme were those associated with the seismic source. A soft-start procedure was used, where the power was built up slowly in the seismic array, firstly using the low volume guns and increasing slowly to full power. The first shots were therefore of a lower sound level than normal, allowing any marine mammals or fish in the area to move away without causing them physical damage. This soft start procedure was conducted in accordance with the JNCC Guidelines for Minimising Acoustic Disturbance to Marine Mammals from Seismic Surveys. Effort-related Cetaceans sightings were recorded during the seismic survey and passed on to JNCC.
The seismic survey programme was also undertaken in accordance with the Enterprise’s Environmental Management System (EMS) and the International Association of Geophysical Contractors (IAGC) Environmental Guidelines for Worldwide Geophysical Operations.
During the seismic survey programmes, any leakages of cable fluid were directed to the oily bilge water tank system, with no discharges to the marine environment. All petroleum products were stored in approved labelled tanks which were bunded to retain accidental spillage and valves
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 16 RSK/H/P/P8069/03/04/Appendices Rev01
between connected fuel tanks were kept closed to minimise the amount of oil that would be lost if a tank was ruptured.
All vessels operating on behalf of Enterprise had safety certificates, and all marine operations were covered by an oil spill contingency plan (OSCP) approved in advance of operations by the Irish Coastguard. The OSCP detailed the most appropriate methods of response to any spill.
Residual Impacts of the Seismic Survey Programmes
Overall, as a consequence of the limited duration of the Corrib seismic survey programmes and the mitigation measures employed to reduce or avoid potential impacts or disturbance, no significant environmental impacts were predicted and none were subsequently observed.
Exploration and Appraisal Drilling Programme
Overview of Exploratory and Appraisal Drilling
The exploration (or wildcat well) is defined as “the first well to be drilled in a geographic region”. The drilling of the exploration well is the beginning of the final stages of exploration and is the first opportunity to actually bring back to the surface for analysis samples of sub-surface rocks and fluids.
If, as a result of drilling an exploration well, it is determined that there appears to be sufficient hydrocarbon presence to justify activity, then appraisal wells will be drilled. The purpose of drilling appraisal wells is to define the hydrocarbon reservoir. This involves locating the boundaries of the reservoir and determining its shape and size, determining rock properties and reservoir fluid properties, and defining the types of rocks, fluids, and pressures which must be drilled through to reach the reservoir. Appraisal wells are necessary in order to:
• gather sufficient information on which to base a decision as to whether there is economic justification for proceeding with development of the hydrocarbon reservoir; and
• provide additional information relative to the reservoir and its associated geologic environment, so as to permit preparation of an effective reservoir development plan. This development plan will be used over the productive life of the reservoir, to most effectively and efficiently recover maximum hydrocarbon in a reasonable production lifetime within economic limits.
Outline of the Corrib Field Exploratory and Appraisal Drilling Programme
Well 18/20-1 was drilled in the Corrib Field during the summer months of 1996 to explore a potential reservoir identified from the 1994 seismic survey. The well was drilled to a measured depth of 4370 m and revealed some of
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 17
the technical challenges of drilling in the formations at this location. The well was not tested, but was plugged and abandoned.
Subsequent to the above, several appraisal wells were drilled in the Corrib gas field, see Table App 2.1-7. These wells have been completed successfully and have confirmed the scale of the reserves.
Table App 2.1-7: Overview of historical drilling activity in the Corrib Field Well Depth Spud
The drilling and casing plan of wells 18/20-1, 18/20-2Z and 18/25-1 followed a conventional design, incorporating a 26” surface casing. The later wells 18/20-3, 18/20-4 and 18/25-3 used ‘slimhole’ four section design without a 26” section.
Well 18/25-3, drilled in 2001 is too recent for some information to be available at the time of writing, and has not been included further in this historical overview.
Environmental Description
The background data used to determine the impacts of the exploration and appraisal drilling programme is taken from Chapter 7 of the EIS. It should be noted that previous non-statutory EIAs have been produced by Rudall Blanchard Associates, on behalf of Enterprise, to cover appraisal wells.
There have been a number of sediment surveys carried out within the Corrib Field since 1998, both pre and post drilling, for most of the individual wells. These surveys have been in compliance with Fisheries Research Centre requirements. Prior to 2000, sediment surveys consisted of chemical analysis. A summary of the surveys for each of the wells is presented in Table App 2.1-8.
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 18 RSK/H/P/P8069/03/04/Appendices Rev01
Table App 2.1-8: Summary of the surveys carried out in the Corrib Field Well location
Surveys Well number
Lat (N) Long (W) Pre Post 18/20-1 54°20’47.554” 11°05’41.114” ROV 1996 GS 1997, 98 & 2000 18/20-2z 54°20’20.169” 11°03’26.819” ROV 1998 ROV 98, GS 98 & 2000 18/25-1 54°19’09.119” 11°02’54.963” None ROV 1999 & GS 2000 18/20-3 54°20’51.419” 11°02’15.468” ROV 2000 ROV 2000 & GS 2000 18/20-4 54°20’19.348” 11°03’26.173” GS 2000 ROV 2000 18/25-3 54°19’14.467” 11°04’09.378” ROV 2001 ROV 2001 ROV = remotely operated vehicle, GS = Gardline Surveys No results available from the 2001 survey to date.
The results from the 2000 survey are provided in sections 7 and 8 of the main EIS. Figure 7.3 from the main EIS provides some of the invertebrate results from the survey undertaken in 2000.
Emissions, Discharges and Waste Inventory
Well Site Survey
In order to ensure that there are no potentially hazardous sections close to the surface of the seabed through which the well will be drilled, a rig site survey or “geohazards survey” is usually carried out. The seismic source is smaller that that used for 2d and 3 d seismic surveys (160 cubic inches compared with 4000 cubic inches), and the surveys lasted only for three or four days per well.
Air Emissions
The air emissions presented in this appendix are based on the recorded fuel use for each well. Categories of fuel included are MGO for the MODU generator engines, and for stand-by and supply vessels, and helicopter fuel. These routine emissions are presented in Table App 2.1-9.
The recorded durations and flow rates of gas from well tests of wells 18/20-2z, 18/25-1, 18/20-3 and 18/20-4 form the basis for the calculation of emissions from well testing. These emissions are presented in Table App 2.1-10.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 19
Table App 2.1-9: Estimated Routine Atmospheric Emissions per Well Fuel Use 18/20-1
102 days 18/20-2z 66 days
18/25-1 107 days
18/20-3 77 days
18/20-4 73 days
18/25-3 112 days
Total (Tonnes)
Diesel Tonnes
2260 1463 2371 1706 1618 2482 11900
Helifuel Tonnes
20 13 22 15 15 22 107
Emission
Substance
18/20-1 Tonnes
18/20-2z 66 Tonnes
18/25-1 Tonnes
18/20-3 Tonnes
18/20-4 Tonnes
18/25-3 Tonnes
Total (Tonnes).
CO2 7298 4724.3 7565.4 5443 5224 7919 38173.7
NOx 145 93.9 152.1 108 103.8 157.8 760.6
CO 29.6 19.2 31 2214 21.2 32.2 2347.2
SO2 18.2 11.8 19.1 13.6 13 20 95.7
NMVOC 4.9 3.2 5.2 3.7 3.5 5.4 25.9
CH4 0.5 0.3 0.5 0.35 0.3 0.5 2.45 Fuel Tonnages supplied by Enterprise Oil. Emissions Factors from UKOOA/EEMS Guidelines The drilling days given for each well include the days for the well testing programme. Helifuel converted from litres at SG 0.8
Table App 2.1-10: Estimated Emissions from Production Well Tests Emission
CH4 77 33 127 93 163 493 Emissions Factors from UKOOA/EEMS Guidelines Gas at 17.02 g/mole Condensate at 0.5 bbl/Mmscf
Discharges to Water
The wells that have been drilled to date have involved marine discharge of cuttings, mud chemicals, routine drainage and service waters. In addition to these, a hydraulic fracturing operation was carried out for well 18/25-3. This operation involved the discharge of 28 milliCuries of gamma radiation under a licence authorised by the Radiological Protection Institute of Ireland.
Cuttings
The WBM cuttings from the 36” section of all wells have been discharged at the seabed. The cuttings from the 26” sections of wells 18/20-1, 18/20-2z and 18/25-1 were also discharged at the seabed. WBM cuttings from the 17.5” sections of 18/20-3 and 18/25-3 were discharged at the seabed.
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 20 RSK/H/P/P8069/03/04/Appendices Rev01
WBM cuttings from the 17.5” sections of 18/20-1, 18/20-2z and 18/25-1, and the 12.25” section of 18/20-1 (to 2098m) and 18/20-2z were discharged to the sea from the shale shakers.
Some SBM shale shaker cuttings from the 12.25” sections of 18/20-1 (below 2098 m), and from the 12.25” sections of all the subsequent wells except for 18/20-2z were discharged to sea. Coarse cuttings from the 8.5” sections of all the appraisal wells were discharged to the sea. A policy of containment of the finer SBM cuttings for transport to shore was instituted for well 18/20-3. For well 18/25-3 all of the cuttings and centrifuge discharges produced from sections where oil based mud was used were contained. The 12 ¼” and the 8 ½” sections were drilled using LTOBM, and a total of 1089 tonnes were contained in vacuum sealed skips and transported to shore for re-cycling.
A summary of the drilling activities carried out up to 2001 in the Corrib Field is included in Table App 2.1-11.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 21
Table App 2.1-11: Summary of Historical Drilling Activity in the Corrib Field
36” hole washes out to 45 ½” average during drilling with WBM; 26” hole washes out to 30.75” average during drilling with WBM; 17 ½” hole washes out to 19.25” average during drilling with WBM; 12 ¼” hole washes out to 13” average during drilling with SBM; 8 ½” hole washes out to 9” average during drilling with SBM;
(1) SBM discharged from the rig is calculated on the basis of a mass balance; SBM discharged = total SBM brought out – SBM returned for re-cycling (2) Ecomul with base fluid containing LAO, PAO and Paraffin. PAO was not included in subsequent Ecomul formulations (3) SBM (Ester) only used for 8 ½” hole (4) Volume calculated on the basis of SBM specific gravity of approx 0.7 t/m3
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 22 RSK/H/P/P8069/03/04/Appendices Rev01
Mud Chemical Usage
The main constituents of the chemical discharge from the Corrib Field wells, in terms of discharged mass, comprise barite, potassium chloride, sodium chloride, bentonite, calcium chloride and synthetic base fluid from SBM discharged on cuttings, see Table App 2.1-12.
The chemicals belonging to HOCNF environmental categories other than E are BW Envirowash 2 (D), BW Enviroclean (D), BW Envirocor (C), BW Biocide (D), BW Defoamer (C), BW Biolube (D), Proxel XL2 (D), and the SBM base fluids.
Table App 2.1-12: Reported Tonnage of Mud Chemical Discharges from Corrib Field Wells
The assumptions on which the estimation of drainage water discharges were made in Chapter 15 are here used to estimate the discharge from the wells which have been drilled to date. This is based on the drilling days and an allowance of 7 days for mobilisation and demobilisation.
Paper and cardboard 1400 kg 1500 kg 1350 kg 1400 kg
1450 kg
Metal or glass packaging 150 kg 170 kg 150 kg 160 kg
145 kg
Used cloth and gloves
Oily rags etc 600 kg
Oily rags etc 650 kg
Oily rags etc 470 kg
Oil rags etc 580 kgs
Oil rags etc 610 kgs
Miscellaneous scrap metal 16000 kg 18000 kg 14000 kg 13000 kg
15000 kg
Cases/ wooden palettes N/A1 N/A1 N/A1 N/A1 N/A1
Electric/ electronic -
128 fluorescent
lamps 16 x
Mercury vapour lamps
63 fluorescent
lamps 10 x
Mercury vapour lamps
118 fluorescent
lamps 14 x Sodium 8 x Mercury
vapour lamps
75 fluorescent
lamps 12 x
Mercury vapour lamps
Sewage sludge N/A2 N/A2 N/A2 N/A2 N/A2 1 Cases/Wooden pallets are returned to original vendor for reuse. 2 The Sedco 711 has a sewage treatment plant so nothing is shipped from rig
In addition, periodical helifuel waste after repairs and inspection of system would have been produced as follows:
410 Litres-06/04-01 to 27/07-01 205 Litres -30/06-00 to 10/09-00 205 Litres-13/04-00 to 29/06-00
Impacts of the Exploration and Appraisal Drilling Programme
The following drilling impacts are addressed retrospectively for the exploration well drilled in 1996 and the subsequent appraisal wells drilled between 1998 and 2000.
In the majority of cases, the impacts from the drilling operations would have been the same as those described in Section 7.8.1.1 (impacts on flora and fauna), Section 10.5 (impacts on air) and Section 9.15.1 (impacts to water).
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 25
The exception to this is there will be no further rig site surveys (future wells will be drilled in areas which have already been subject to surveys), and that the practice of discharging SBM cuttings which was carried out during the exploration and appraisal drilling programme is now discontinued. During drilling of well 18/25-3, and for subsequent wells, OBMs were (and will be) used rather than SBMs. The resulting OBM and associated cuttings were then taken ashore for disposal.
Impacts of Rig Site Survey
The effects of using a small airgun source of approximately 160 cu in. (compared to 3000-4000 cu in. for a seismic survey) for a period of 6 - 20 days for the 6 wells drilled to date would not have posed a significant threat to cetaceans unless they were within close proximity of the array. This situation was avoided as far as possible, by following the JNCC ‘Guidelines for Minimising Acoustic Disturbance to Marine Mammals from seismic surveys’.
Impacts of Vertical Seismic Profiling
VSP takes place after the well has been drilled and involves a number of loggers being strung at 10 m depth intervals down the well (in the case of well 18/25-3 the string contained 12 loggers). A seismic source is used close to the surface to generate a signal, and the loggers record the signal at the different depths in the well. The string of loggers is then moved up the well, and the seismic source is fired again, for well 18/25-3 a total length of 2400 m was covered, involving 20 movements of the string and 20 firings of the seismic source. The single airgun used as the seismic source for VSP has a volume of 500 cubic inches (approximately 1/6 to 1/8 of that used in 3-D seismic surveys). Impacts from VSP on each of the wells drilled in the Corrib Field are expected to have been minor, and very short-term.
Impacts of SBM Cuttings Discharge
For the wells drilled between 1996 and 2000, water based muds (WBM) were used for the upper whole sections and synthetic based muds (SBM) for the lower hole sections. The cuttings and associated WBM and SBM were then discharged to the seabed.
It is generally acknowledged that discharge of SBM cuttings has a greater impact than the discharge of WBM cuttings as the rate of biodegradation of SBMs is generally slower. The cuttings discharged would have fallen to the seabed within a limited area around the point of discharge from the cuttings chute. Within this limited area there may have been smothering effects and changes in benthic community structure related to changes in particle size composition and organic enrichment and impacts on demersal fish from water column turbidity effects. In addition to the impacts that resulted directly from the decomposition of cuttings, it is possible that the constituent chemicals of the drilling fluids may have exhibited some degree of toxicity.
Campbell (1998) reviewed the available information on biodegradation of SBM. A number of generalisations were made about the environmental
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 26 RSK/H/P/P8069/03/04/Appendices Rev01
behaviour of SBMs and the factors which should be considered in the evaluation of persistence as follows:
• degradation rates in sediments decrease as base fluid concentration increases. This suggests that “dispersability” is a factor that should be considered in the assessment of SBMs;
• sediment types such as sand or mud have an influence on degradation rate. Degradation rates in sand have been shown to be significantly slower than in mud (Munro, 1997); and
• full evaluation of degradation should address rates under both anaerobic, as might be found in the main area of the cuttings accumulation, and aerobic conditions, as may apply in the peripheral areas of cuttings accumulations.
The most definitive information concerning the impacts of the SBM cuttings in the Corrib Field has been obtained from post-drilling monitoring, as described below.
Impacts of discharge of radioactive material
It is considered that the material discharged (isotopes of scandium, antimony and iridium) will have had a negligible impact in the area in which it was discharged. The amount of material discharged was small, and the half-lives of the isotopes are all shorter than 84 days.
Chemical Monitoring:
M-Scan and Gardline undertook pre and post drilling sampling surveys around the well site location for well 18/20-1 in 1996 and 1997 respectively. Subsequent post drilling sampling was undertaken by Gardline in 1998 in the vicinity of well 18/20-1 and the newly drilled well 18/20-2z. Sediment from around well 18/25-1 was sampled both before and after drilling using an ROV. A wider survey was carried out in the Field in 2000, during which sediment was analysed for its chemical and biological content, all sites around the manifold were sampled whilst well 18/20-3 was being drilled. Once the rig moved from 18/20-3, samples were taken from around that well position.
Wells 18/20-1 and 18/20-2z were both drilled with SBM systems. SBM with a base fluid comprising a mixture of paraffin & LAO and PAO was used for well 18/20-1 while an ester base fluid was used for well 18/20-2z.
The following paragraphs provide an overview of the status of the sediments within the Corrib Field at various points after the wells had been drilled.
Exploratory Well Monitoring:
The findings of the monitoring survey data for well 18/20-1 indicate that elevated levels of drilling muds were present within 250 m of the well site, with the highest concentrations found within 50-100 m from the well site.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 27
Samples taken on two transects around the well site indicated that SBM concentrations in the sediment had generally decreased over time. This could be attributed to biodegradation of the SBM base fluid.
Further, the findings indicated that different components of the SBM base fluid degraded at different rates with poly alpha olefin (PAO) degrading slower than linear alpha olefin (LAO) and paraffin. In particular LAO and paraffin were found to originally make up 80% of the SBM in the samples taken in the first survey. Subsequently they were found to make up only 20% of the SBM base fluid component in the samples after 2 years, while at the same time, almost no reduction in the PAO concentration was observed.
Appraisal Well Monitoring:
Following drilling of well 18/20-1, the PAO, which was the least biodegradable component of the base fluid formulation, was removed from the mud formulation.
For well 18/20-2z, elevated concentrations (up to 610 ppm) of the ester base fluids were observed within 100 m of the well site. Outside of this area concentrations of the base fluid were below detectable limits.
The dominant base oil detected throughout the Field was Ecosol (LAO and paraffin), (except at 18/20-1 where PAO was still part of the base oil formulation). The highest concentration of Ecosol was 3800 µg/g at 100m south of 18/20-3 (drilled in 2000).
Up to 1800µg/g observed in sediments around 18/25-1 in 1999 had decreased to 710 µg/g in 2000. Approximately 1800 µg/g Ecosol was observed on a transect around 18/20-3 in 2000. At the 18/20-1 wellsite in 2000, if it is assumed that there has been no biodegradation of the PAO, then 95% of the other alkanes have been removed by biodegradation.
At wellsites 18/20-1 (sampled in 1998) and 18/25-1 (sampled in 1999) a notable reduction in Total Organic Extractables (TOE) was observed in 2000 compared to the previous surveys. TOE at 18/20-1 decreased by 85%, and by 53% at 18/25-1.
To summarise, the sediments in the Corrib Field showed differing degrees of recovery after the drilling of the wells. The level of recovery was dependent upon the proximity of the nearest well, and the time since it was drilled. The majority of the impacts have been as a result of discharge of synthetic mud on cuttings.
Biological Monitoring:
Macrofaunal data collected during the survey in 2000 indicated that the sediment around well 18/20-1 showed the greatest level of macrofaunal disturbance within the Corrib Field. The macrofaunal population here indicated a paucity in both abundance (c. 40-50%) and species number (c. 50%) when compared to uncontaminated sites in the same area. As a
Corrib Offshore EIS Enterprise Energy Ireland
APP2.1 - 28 RSK/H/P/P8069/03/04/Appendices Rev01
consequence, this station clustered separately to all others when using community statistics (PRIMER), although the overall level of disturbance is not thought to be severe. It is anticipated that as levels of organics in the sediment fall back to baseline levels, the distribution of fauna is expected to follow a similar trend.
Statistical analysis of the remaining wells indicated that the faunal communities immediately surrounding the well sites and some of the outer stations indicated a similar, but less marked impact to that recorded at 18/20-1. Should the same rate and level of recovery be replicated for these wells then a similar level of community succession is expected and consequently alterations to the biological population. The only well which appeared to remain relatively undisturbed during drilling activities was that of 18/20-2z, which clustered statistically with the reference stations. This would suggest that the level of impact caused by the ester based drilling mud used at this site was insignificant.
The findings outlined above indicate that the area of organic enrichment caused by the base fluid on the cuttings is limited to the areas closest to the point of discharge from the cuttings chute, where the accumulations were greatest. It is in these areas that anoxic conditions may have caused mortality of benthic organisms and a reduction in the rate of degradation of the drilling fluid. In the peripheral areas, where the thickness of cuttings is limited, aerobic conditions may have prevailed and a rapid biodegradation of the base fluid is expected.
Mitigation Measures for the Exploration and Appraisal Drilling Programme
The mitigation measures in place for the exploration and appraisal drilling programme were the same as those described in Section 7. However, additional measures were in place due to the discharge of SBM cuttings, as follows:
Impacts associated with the discharge of SBM and cuttings for the appraisal wells drilled between 1996-2000 were minimised by using a predetermined drilling programme and procedures. In addition, the mud and cuttings strategy employed achieved approximately 8% (by weight) retained SBM on cuttings efficiency. SBM cuttings were discharged above sea level, at rig operating draft, to optimise the efficient dispersal of the cuttings and mud. Routine onboard testing (retort) was undertaken of the mud system and sediment monitoring programmes were in place for all wells. It should be noted that whole or spent SBM was not discharged to the marine environment.
Residual Impacts of the Exploration and Appraisal Drilling Programme
The monitoring of the Corrib Field following cessation of SBM cuttings discharge indicates that the impact on the marine benthic environment has been minor and localised.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP2.1 - 29
The area of organic enrichment caused by the base fluid on the cuttings is limited to the areas closest to the point of discharge from the cuttings chute, where the accumulations were greatest. It is in these areas that anoxic conditions may have caused mortality of benthic organisms and a reduction in the rate of degradation of the drilling fluid. In the peripheral areas, where the thickness of cuttings is limited, aerobic conditions may have prevailed and a rapid biodegradation of the base fluid is expected.
It should be noted that Enterprise do not intend to discharge any SBM cuttings during the drilling of future wells. Therefore, it is expected that the sediment contamination levels will decrease further with time.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 4.1: THE HARMONISED OFFSHORE CHEMICAL NOTIFICATION FORMAT (HOCNF) SCHEME
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP 4.1 - 1
The Harmonised Offshore Chemical Notification Format (HOCNF) Scheme
The HOCNF Scheme is an Oslo and Paris Commission (OSPARCOM) initiative established under cover of the Paris Commission Decision 96/3. The aim of the HOCNF initiative is to harmonize the measures and criteria used by the signatory states to regulate chemicals management by the offshore oil and gas industry.
The objective of the HOCNF scheme is to prevent unacceptable damage to the marine environment as a consequence of use, discharge and accidental loss of exploration and production chemicals.
The HOCNF scheme standardizes the requirements for the testing and reporting of all chemicals used by the offshore oil and gas industry operating within the North Sea and North East Atlantic.
The classification system places chemicals into one of five categories, A to E. Chemicals in category A have the potential to cause the greatest damage to the environment, and category E chemicals have the potential to cause the least damage to the environment.
The method of classification used is a two-stage process. Chemicals are first assigned an initial grouping on the basis of toxicity, determined in accordance with the parameters presented in Table 1 below.
Table A.4.1.1: Toxicity Classification Parameters for the HOCNF Scheme
Initial Grouping A B C D E Result for aquatic toxicity data (ppm)
<1 >1-10 >10-100 >100-1000
>1000
Result for sediment toxicity data (ppm)
<10 >10-100 >100-1000
>1000-10000
>10000
The eco-toxicology data used are the results of laboratory tests on aquatic indicator organisms. Acute toxicity is assessed and expressed as either:
• an LC50 test - the concentration of the test substance in sea water that kills 50% of the test batch; or
• an EC50 test - the concentration with a specified sub-lethal effect on 50% of the test batch.
The subject organisms and test protocols that form the basis of the toxicity testing programme are as follows:
• Algae test: Skeletonema costatum (EC50 72 hour test )
The second stage of the classification process allows for an adjustment of the preliminary first stage grouping to reflect the environmental performance criteria, as outlined in Table 2 below.
Table A.4.1.2: Environmental Performance Parameters for the HOCNF Scheme
Increase by 2 Groups (e.g. from C to E)
Increase by 1 Group (e.g. from
C to D)
Do not adjust Initial Grouping
Decrease by 1 Group
(e.g. from C to B)
Decrease by 2 Groups
(e.g. from C to A) Substance is readily biodegradable and is non-bioaccumulative
Substance is inherently biodegradable and is non-bioaccumulative
Substance is not biodegradable & is non-bioaccumulative or Substance is readily biodegradable & bioaccumulates
Substance is inherently biodegradable & bioaccumulates
Substance does not biodegrade & bioaccumulates
The definitions used for the environmental performance criteria used in the second stage of the HOCNF classification process are presented in Table 3 below.
results of >60% biodegradation in 28 days to OSPARCOM HOCNF accepted biodegradation protocol.
Inherently biodegradable
results of >20% & <60% to an OSPARCOM HOCNF accepted ready biodegradation protocol OR result of >20% by OSPARCOM accepted inherent biodegradation study
Not biodegradable results from OSPARCOM HOCNF accepted ready biodegradation protocol OR inherent biodegradation protocol are <20%
Non-bioaccumulative / non-bioaccumulating
Log Pow <3, or results from a bioaccumulation test (preferably using Mytilus edulis) demonstrates a satisfactory rate of uptake and depuration OR the molecular mass is >600
Bioaccumulative / Bioaccumulates
Log Pow >3, or results from a bioaccumulation test (preferably using Mytilus edulis) demonstrates an unsatisfactory rate of uptake and depuration and the molecular mass is <600
Aquatic toxicity data result
LC / EC50 data for Skeletonema costatum, Acartia tonsa or Juvenile turbot (units=ppm or mg/l)
Sediment toxicity data results
LC / EC50 data for Abra alba (generated pre 11/2/94) or preferably, Corophium volutator (units=ppm or mg/kg)
Annual tonnage limits that trigger the requirement for an operator to provide prior notification of use of production chemicals can also be set for each category of chemical used for each installation.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP 4.1 - 3
Under such a notification system, if the suite of production chemicals proposed for a particular installation results in the use of a cumulative total of production chemicals above the trigger value, for a particular category of categories, the operator can be required by the regulatory body, who administer the scheme, to undertake an environmental risk assessment and to provide justification for their selection where alternatives are available (see Table 4 below).
In addition to the basic classification scheme provided above, specific requirements have been set for the testing of drilling fluid types, as outlined in Table 4 below.
Table A.4.1.4: Specific Requirements for Testing of Drilling Fluids
Mud System Parameter Testing Requirements Water based drill-mud systems
containing <5% water-immiscible liquid
Individual component products. Each component product will be classified separately after assessment under the HOCNF.
*Oil based muds >5% v/v water-immiscible liquid
Generic ‘worst-case’ mud systems (i.e. likely most toxic, persistent, or otherwise environmentally damaging)
*Synthetic muds >5% v/v water-immiscible liquid
as above
*Emulsified water based muds
>5% v/v water-immiscible liquid
as above
* full HOCNF data set required as follows; • Toxicity test for Skeletonema costatum, Acartia tonsa & Corophium volutator, for the whole mud system with an agreed ‘worst-case’ formulation; • Log Pow and Koc (base fluid & all knowingly added wholly organic substances of the whole mud except for surfactants) • Aerobic degradation (base fluid & all knowingly added wholly organic substances of the whole mud) • Anaerobic biodegradation tests may be conducted in addition to aerobic tests. • Anaerobic biodegradation data have also been proven to be irrelevant for water soluble materials which do not adsorb to surfaces.
Presence of surfactants may increase the bio-availability of other substances within a preparation. Evidence is required to show that the surfactants within a mud system are sufficiently degradable and will not increase the bio-availability of the base fluid. Otherwise a bio-concentration test may be required for both the base fluid and whole preparation to demonstrate that the surfactants do not significantly increase bio-accumulation potential of the base.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 7.1: BIOTOPES IDENTIFIED FROM THE LANDFALL AND CROSSING LOCATIONS
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP 7.1 - 1
Biotopes identified from the landfall and crossing locations
(Descriptions follow Connor et al., 1997)
Biotope code: LR.YG
Biotope name: Yellow and grey lichens on supralittoral rock
Stable hard substrata in the supralittoral zone are typically characterised by a maritime community of yellow and grey lichens such as Xanthoria parietina and Caloplaca marina. This band is usually found immediately above a zone of Verrucaria maura (Ver), a black lichen which is also present in this zone, though typically less than common. Damp pits and crevices are occasionally occupied by littorinid molluscs and acarid mites. In sheltered areas the transition from this biotope to Verrucaria maura (Ver) beneath is often indistinct and a mixed zone of YG and Ver may occur. With increasing wave exposure both zones become wider and more distinct.
Biotope code: LR.Ver
Biotope name: Verrucaria maura on littoral fringe rock
A band of the black lichen Verrucaria maura typically occurs on bedrock or stable boulders and cobbles in the littoral fringe. It occurs below the yellow and grey lichen zone (YG) and above communities of barnacles and fucoid algae. This type covers a wide range of wave exposures and several variants are defined. On exposed shores Verrucaria spp. may occur with sparse barnacles, (Chthamalus spp. or Semibalanus balanoides) (Ver.B). Where the ephemeral red alga Porphyra umbilicalis occurs this should be recorded as Ver.Por. More sheltered shores tend to lack these species (Ver.Ver).
Biotope code: SLR.Pel
Biotope name: Pelvetia canaliculata on sheltered upper shore rock
Lower littoral fringe bedrock or stable boulders on sheltered shores are characterised by a dense cover of the upper shore fucoid Pelvetia canaliculata. The fucoid overgrows a crust of black lichens Verrucaria maura and Verrucaria mucosa, or Hildenbrandia on very sheltered shores. This biotope lacks the cover of barnacles beneath the Pelvetia commonly found on more exposed shores (PelB). The littorinids Littorina littorea and L. saxatilis occur. The red alga Catenella caespitosa is characteristic of this biotope, as is the lichen Lichina confinis.
Corrib Offshore EIS Enterprise Energy Ireland
APP7.1 - 2 RSK/H/P/P8069/03/04/Appendices Rev01
Biotope code: SLR.Fspi
Biotope name: Fucus spiralis on moderately exposed to sheltered upper eulittoral rock
Moderately exposed to very sheltered upper eulittoral bedrock and boulders are typically characterised by a band of the spiral wrack Fucus spiralis overlying the black lichens Verrucaria maura and V. mucosa. Limpets Patella vulgata, winkles Littorina spp. and barnacles Semibalanus balanoides are usually present under the fucoid fronds and on open rock. During the summer months ephemeral green algae, such as Enteromorpha spp. and Ulva lactuca, may also be present. This zone usually lies below a Pelvetia canaliculata zone (Pel); occasional clumps of Pelvetia may be present (usually less than common) amongst the F. spiralis. In areas of extreme shelter, such as in Scottish sealochs, the Pelvetia and F. spiralis zones often merge together forming a very narrow band. Fspi occurs above the Ascophyllum nodosum (Asc) and/or Fucus vesiculosus (Fves) zones and these two fucoids may also occur, although Fucus spiralis always dominates. Vertical surfaces in this zone, especially on moderately exposed shores, often lack the fucoids and are characterised by a barnacle-Patella community (BPat).
Biotope code: SLR.Fves
Biotope name: Fucus vesiculosus on sheltered mid eulittoral rock
Moderately exposed to sheltered mid eulittoral rock characterised by a dense canopy of large Fucus vesiculosus plants (typically Abundant-Superabundant). Beneath the algal canopy the rock surface has a sparse covering of barnacles (typically Rare-Frequent) and limpets, with mussels confined to pits and crevices. Littorina littorea and Nucella lapillus are also found beneath the algae, whilst Littorina obtusata and Littorina mariae graze on the fucoid fronds. The fronds may be epiphytised by the filamentous brown alga Elachista fucicola and the small calcareous tubeworm Spirorbis spirorbis. In areas of localised shelter, Ascophyllum nodosum may also occur, though never at high abundance (typically Rare-Occasional) -(compare with Asc). Damp cracks and crevices often contain patches of the red seaweed Osmundea (Laurencia) pinnatifida, Mastocarpus stellatus and encrusting coralline algae. This biotope usually occurs between the Fucus spiralis (Fspi) and the Fucus serratus (Fser) zones; both of these fucoids may be present in this biotope, though never at high abundance (typically < Frequent). In some sheltered areas Fucus vesiculosus forms a narrow zone above the Ascophyllum nodosum zone (Asc).
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP 7.1 - 3
Biotope code: SLR.Asc
Biotope name: Ascophyllum nodosum on very sheltered mid eulittoral rock
Sheltered to very sheltered mid eulittoral rock with the knotted wrack Ascophyllum nodosum. Several variants of this biotope are described. These are: full salinity, tide-swept and variable salinity.
Biotope code: SLR.Fcer
Biotope name: Fucus ceranoides on low salinity eulittoral rock
Bedrock and stable boulders in the eulittoral zone that are subject to reduced salinity may be characterised by the horned wrack Fucus ceranoides. As this fucoid is more tolerant of reduced salinity than the other fucoids, F. ceranoides tends to replace Fucus spiralis, Fucus vesiculosus and Ascophyllum nodosum towards the upper reaches of estuaries and sealochs. This biotope may, however, still contain other fucoids, though Fucus ceranoides always dominates. Species richness is typically low in this biotope. Since areas of bedrock and stable boulder are generally scarce within estuarine systems, this community is more commonly encountered on stable mixed substrata (see FcerX).
Biotope code: SLR.FvesX
Biotope name: Fucus vesiculosus on mid eulittoral mixed substrata
Sheltered and very sheltered mid eulittoral pebbles and cobbles lying on sediment are typically characterised by Fucus vesiculosus. FvesX is usually subject to some variability in salinity from riverine input or, in more marine conditions, the habitat consists predominantly of smaller stones which are too unstable for Ascophyllum nodosum to colonise to any great extent (compare with AscX). This biotope typically differs from Fves in having a less dense canopy and reduced richness of epifaunal species, presumably as a result of the increased siltation, variable salinity and lack of stable substrata. In addition, the sediment between patches of hard substrata often contains the lugworm Arenicola marina, cockles Cerastoderma edule or the ragworm Hediste diversicolor. Littorinids, particularly Littorina littorea, commonly graze on the algae. Ephemeral algae such as Enteromorpha spp. are often present, especially on any more mobile pebbles during the summer. Limpets are less common than in AscX, because of the limited availability of larger rocks.
Corrib Offshore EIS Enterprise Energy Ireland
APP7.1 - 4 RSK/H/P/P8069/03/04/Appendices Rev01
Biotope code: SLR.FcerX
Biotope name: Fucus ceranoides on reduced salinity littoral mixed substrata
Boulders, cobbles and stones in the eulittoral zone that are subject to reduced salinity conditions may be covered by Fucus ceranoides. This biotope is typical where streams run across the shore, or towards the heads of marine inlets. Other fucoids may occur, but are generally scarce. Amongst the fucoid algae, opportunistic green algae such as Enteromorpha spp. and Ulva lactuca are frequently encountered. Littorinid molluscs and clumps of large Mytilus edulis may be present. Species diversity is generally low, however, with red algae being rare or absent. Sediment, on which the cobbles and boulders frequently lie, often contains infaunal species such as the lugworm Arenicola marina and the ragworm Hediste diversicolor.
Biotope code: LGS.Tal
Biotope name: Talitrid amphipods in decomposing seaweed on the strand-line
This strand-line community may occur on any shore where decomposing seaweed accumulate on the extreme upper shore strand-line. This community occurs on a wide variety of substrata from shingle and mixed substrata through to fine sands. The shores are usually depositional in nature but the community may also occur on mixed and rocky shores in some circumstances. The decaying seaweeds provide cover and humidity for Talitrus saltator and other components of the community. The amphipods Orchestia spp. may also be present, as well as enchytraeid oligochaetes. Polychaetes, molluscs and other crustaceans may be brought in on the tide, but are not necessarily associated with the infaunal community. Further analysis of the data may determine that Orchestia spp. are associated with a denser strand and that there are differences in the community dependent upon the substratum-type. Talitrus saltator may occur further down the shore, almost invariably accompanied by burrowing amphipods such as, Bathyporeia spp. (LGS.AEur).
Biotope code: LGS.AP
Biotope name: Burrowing amphipods and polychaetes in clean sandy shores
A level one biotope to be used when there is insufficient information to assign a level two biotope. The mid and lower shore of clean sandy beaches on wave-exposed or moderately wave-exposed coasts may support a community of burrowing amphipods and polychaetes, sometimes with bivalves such as Angulus tenuis. The sand is usually medium or fine-grained with little organic matter. The finer particles, together with the
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP 7.1 - 5
location of the habitat on the lower shore results in poor drainage. The community consists of burrowing amphipods (Pontocrates altamarinus, P. arenarius, Bathyporeia elegans, B. guilliamsoniana, B. pelagica, B. pilosa and B. sarsi), the isopod Eurydice pulchra and polychaetes (including Scolelepis squamata, Paraonis fulgens and Nephtys cirrosa and Arenicola marina). The presence of polychaetes is seen as coloured burrows running down from the surface of the sediment. The sediment is often rippled and typically lacks an anoxic black sub-surface layer.
Biotope code: LMU.HedStr
Biotope name: Polychaetes dominated by Hediste diversicolor and Streblospio shrubsolii in sandy mud and mud shores
Sandy mud and mud shores in sheltered marine inlets and estuaries subject to variable or reduced salinity. The biotope is typically found on the mid and lower shores and is often associated with the presence of sea defences, rocky outcrops, rubble training walls or shallow layers of cobbles and pebbles in the sediment in the upper and mid estuary. In addition, the presence of nearby sewage outfalls or a high organic content probably influences the infaunal community. Tidal streams can be strong, further supporting the possibility that this biotope has a disturbed habitat. The infaunal polychaete community includes species with a limited salinity range tolerance such as Streblospio shrubsolii, Caulleriella (Tharyx) killariensis and Manayunkia aestuarina. In addition to the mentioned polychaetes, Hediste (Nereis) diversicolor, Nephtys hombergii, Pygospio elegans, the burrowing amphipod Corophium volutator, the mud snail Hydrobia ulvae and the bivalves Macoma balthica and Abra tenuis are characterising species. In the absence of the more frequently encountered characterising species, the presence of the isopod Cyathura carinata or polychaetes Polydora spp., Heteromastus filiformis or Ampharete grubei are also indicative of this biotope. The sediment is anoxic and black close to the surface and remains water saturated throughout the tidal cycle. The frequency and abundance of oligochaetes, particularly Tubificoides benedii and Tubificoides pseudogaster, is greater than in LMS.HedMac, whilst the closely related LMS.HedMac.Pyg rarely has Streblospio shrubsolii or Manayunkia aestuarina and has a greater frequency and abundance of Cerastoderma edule and Eteone longa. LMU.HedScr is similar to this biotope, but is slightly less muddy, has a higher frequency and abundance of bivalve species and a less diverse range of polychaete species, reflecting the more stable habitat of LMU.HedScr. The polychaete species richness is greater than in LMU.HedOl. The number of species that may be present in this biotope and the number of transition areas along salinity, wave-exposure and sediment particle size continua make this biotope potentially very variable in species content.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 7.2: DESCRIPTIONS OF BIOMAR SITES IN BROADHAVEN BAY
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP7.2 - 1
Table A.7.2.1: List of species recorded from S of Rinroe Point, Broadhaven and their relative abundance. Species names follow Howson and Picton (1997). Abundance scale follows Hiscock (1986). S - super abundant, A - abundant, C - common, F - frequent, O - occasional, R - rare. Porifera (sponges) Psammechinus miliaris O Scypha ciliata O Echinus esculentus O Polymastia mamillaris F Holothuria forskali O Halichondria panicea O Esperiopsis fucorum O Tunicata (sea squirts) Clavelina lepadiformis F Anthozoa (anemones) Polyclinum aurantium O Urticina felina F Morchellium argus O Bunodactis verrucosa O Aplidium nordmanni F Sagartia elegans O Aplidium punctum O Diplosoma listerianum O Hydrozoa (hydroids) Diplosoma spongiforme O Plumularia setacea R Botryllus schlosseri F Sertularia argentea O Obelia geniculata F Pisces (fish) Lophius piscatorius R Polychaeta (worms) Psetta maxima R Eupolymnia nebulosa F Pomatoceros triqueter O Algae (seaweeds) Scinaia interrupta R Crustacea (crabs and barnacles)
Dilsea carnosa O
Balanus crenatus O Callophyllis laciniata F Pagurus bernhardus F Corallinaceae F Galathea squamifera O Corallina officinalis O Inachus phalangium O Ahnfeltia plicata O Macropodia rostrata R Phyllophora crispa F Pirimela denticulata R Plocamium cartilagineum R Cancer pagurus O Lomentaria orcadensis R Liocarcinus puber O Ceramium sp. O Xantho incisus O Acrosorium venulosum F Delesseria sanguinea O Mollusca (snails and bivalves)
Hypoglossum hypoglossoides F
Gibbula cineraria F Membranoptera alata O Calliostoma zizyphinum O Heterosiphonia plumosa O Aplysia punctata C Brongniartella byssoides F Aegires punctilucens P Laminaria spp C Polycera faeroensis R Laminaria hyperborea F Archidoris pseudoargus O Bryopsis plumosa O Pelecypoda indet. R Bryozoa (sea mats) Membranipora membranacea
F
Scrupocellaria reptans F Bicellariella ciliata O Echinodermata (starfish and urchins)
Henricia oculata O Asterias rubens F Marthasterias glacialis O Ophiothrix fragilis O Amphipholis squamata P
Corrib Offshore EIS Enterprise Energy Ireland
APP7.2 - 2 RSK/H/P/P8069/03/04/Appendices Rev01
Descriptions of other sites in Broadhaven Bay, from the BioMar viewer (Picton and Costello, 1998):
E Illandaruck, Broadhaven 54° 18.48' N 009° 59.52' E
The site was located on the east side of an islet adjacent to a large headland and sheltered from the prevailing south-west winds. The substratum from 25 - 34 m BCD was gently sloping bedrock which gave way to a sandy plain at 34 m BCD of well sorted medium sand with bivalves and Echinocardium spp. The bedrock was characterised by Corynactis viridis, Securiflustra securifrons, Alcyonium glomeratum and Alcyonium digitatum. Sertularella spp. were occasional. Caryophyllia smithii was conspicuously absent.
Gubastuckaun, Broadhaven 54° 18.06' N 009° 58.92' E
The site was located at the tip of a headland on the east side of a large north-facing bay on the west coast of Ireland. The seabed from 30 - 40 m BCD consisted of sloping bedrock, with a vertical face to the north. At 40 m BCD there were large blocks of rock lying on the bedrock and embedded in coarse sand. The coarse sand plain extended offshore.
S of Gubastuckaun, Broadhaven 54° 17.99' N 009° 58.98' E
The site was located to the south of a headland on the east side of a large north-facing bay on the west coast of Ireland. The seabed from 13 m to 30 m BCD consisted of bedrock ridges with deep, vertical-sided gullies. Some boulder holes were present and at 20 m BCD was a shallow cave with the colonial anemone Parazoanthus anguicomus in abundance.
N of Cone Island, Broadhaven 54° 17.27' N 009° 58.20' E
Situated on a north-east facing stretch of coastline on the side of a large open coast inlet. The site was adjacent to a small islet which ran in a north-south direction extending into the sublittoral as a ridge. The seabed at 29.8 m BCD was the bottom of a boulder strewn gully with bedrock rising almost vertically to 23.2 m BCD before flattening out. The area was formed into a series of ridges and gullies. The dominant organisms were sponges Axinella spp. with Alcyonium glomeratum and Caryophyllia smithii.
Cave, S of Cone Island, Broadhaven 54° 16.98' N 009° 58.26' E
The site was located on the north-eastern side of the Mullet Peninsula, facing a broad open coast bay, sheltered from the prevailing winds. The shore was high cliffs with many cave entrances at the bases. The cave surveyed went back into the cliff 4 - 5 m before turning right and forming a swim through to emerge around a small headland. The cave was approximately 4 m high varying in depth from 4.2 m BCD to its roof at 0.5 m
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP7.2 - 3
BCD. The floor was strewn with boulders which were likely to be mobile having scoured the lower 0.5 m of the walls. The remaining walls and roof had a dense cover of sponges, anemones and ascidians.
E of Ooghran Point, Broadhaven 54° 16.67' N 009° 57.12' E
Bedrock in angular ridges with pink coralline crusts almost continuous over the rock. Animals were sparse, with Echinus esculentus, Holothuria forskali, Haliclona viscosa and Pachymatisma johnstonia most abundant.
W of Duveel Point, Broadhaven 54° 16.49' N 009° 55.44' E
The site was located to the east of a north-facing headland in a large, open, north-facing bay on the west coast of Ireland. The seabed at 20 - 30 m BCD consisted of ridges of rock varying in height from 0.5 m to 2 m. The rock was pink and sparsely covered with algae, the algae was more dense at 20 m with scattered kelp plants throughout the zone. The fauna was very sparse with Holothuria forskali and Echinus esculentus frequent. The starfish Stichastrella rosea was present in considerable numbers.
N of Gubacashel, Broadhaven 54° 16.20' N 009° 53.22' E
The site was located on a headland in a large open coast bay where the bay narrowed to an inlet approximately 1 km across. The site was possibly subject to some tidal streams. The seabed at 24.5 m BCD consisted of pinnacles and ridges of 'sculptured' bedrock rising from a boulder/cobble plain. The boulders were likely to be mobile in bad weather possibly scouring the bedrock. The boulders were not surveyed. The bedrock supported Antedon bifida with red foliose algae and Alcyonium digitatum on the upward-facing areas. Kelp was present at 21.5 m BCD but the rock was not surveyed any shallower.
S of Rinroe Point, Broadhaven 54° 17.39' N 009° 50.40' E
The site was located in the centre of a wide bay which was backed by a long beach. The bay was situated on the open coast but with protection from the south-west by the northern end of the Mullet peninsula. The seabed at 12.5 m BCD was a level plain of cobbles and boulders with Laminaria hyperborea on the larger pieces of rock. Between the large boulders was a lot of drift/unattached algae.
SE of Slugga Rock, Broadhaven 54° 18.06' N 009° 51.84' E
The site was located on the eastern shore of a large, open, north facing bay on the west coast of Ireland. A small headland extended underwater as a rocky ridge, out towards a breaking rock. The seabed generally sloped gently underwater, with small cliffs and gullies. From 6.7 to 13.9 m BCD was fairly dense kelp forest with an understorey of red foliose algae.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 7.3: INTERTIDAL MACROFAUNAL ABUNDANCE FROM THE LANDFALL AND ADJACENT SITES
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP 7.3 - 1
Table A.7.3.1: Intertidal macrofaunal abundance from the landfall and adjacent sites.
T1 T2 T4 High
water Mid water
Low water
High water
Mid water
Low water
Mid water
A B C A B C A B C A B C A B C A B C A B C Oligochaeta 1 2 1 13 11 5 3 6 4 Scololepis sp 1 Nereis diversicolor 1 2 1 Manayunkia estuarina
Note: Rocky shore at Transect 3 prevented cores being taken from these locations.
Only a mid tide level core taken from Transect 4.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 7.4: SYNOPSES FROM CONSERVATION SITES IN THE BROADHAVEN BAY AREA
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP7.4 - 1
Broadhaven Bay (candidate Special Area of Conservation (cSAC), Site code: 000472)
Broadhaven Bay is a large bay situated between the north-east side of the Mullet Peninsula and the north-west Mayo coast. Exposure to prevailing winds and wave action diminishes from the mouth toward the head of the bay. Subsidiary inlets along the length of the bay provide further areas of additional shelter. The bay encompasses a range of habitats from extremely exposed bedrock at Benwee Head to sheltered sediments and saltmarsh in the inner bay.
Broadhaven Bay contains excellent examples of four habitats listed on Annex I of the EU Habitats Directive, namely Atlantic saltmarsh, tidal mudflats, reefs and large shallow bay. The shoreline is comprised mostly of shingle beaches and sandy beaches, as well as marginal habitats such as cutaway bog, heathland, dune grassland and machair, wet grassland, tidal rivers and dry pasture, which is used for grazing. There are several extensive areas of intact saltmarsh, with Thrift (Armeria maritima), Saltmarsh Rush (Juncus gerardii), Buck's-horn Plantain (Plantago coronopus), Sea Arrowgrass (Triglochin maritima), Common Scurvygrass (Cochlearia officinalis) and Common Saltmarsh-grass (Puccinellia maritima). Parts of the saltmarsh are heavily grazed.
Sheltered littoral sediments in Broadhaven Bay are characterised by fine sand. Sand hoppers live under drift weed in the upper shore. Lugworms (Arenicola marina) are present in the mid-shore, whereas different worm species (Scolelepis foliosa and Spiophanes bombyx) and crustacea (Bathyporeia elegans and Crangon crangon) live in the lower shore. Bivalve molluscs (Cerastoderma edule and Angulus tenuis) occupy both the middle and low shore. Sublittoral sediments range from coarse sand in exposed areas to fine sand in more sheltered areas in the inner bay. The coarse sand is characterised by the bivalve Lutraria lutraria. Echinocardium and bivalves characterise the sediment moderately exposed to wave action. In sheltered areas with medium sand and moderate current, communities of burrowing anemones, bivalves, the red seaweed Gracillaria verrucosa, and a community of hydroids, in particular Sertularia argentea occur.
There are good examples of wave-surged cave communities in shallow water with the anemone, Phellia gausapata typically found in areas very exposed to wave action. The rare anemone Parazoanthus anguicomus and the soft coral Alcyonium glomeratum are present in a deeper water cave. Dercitus bucklandi, which is characteristic of caves and crevices, has also been recorded.
The reef communities of Broadhaven Bay are subject to a range of conditions, from very exposed to wave action to very sheltered from wave action. Tidal streams are weak or negligible. Much of the bedrock is ridged with steeply sloping sides and gullies between the ridges. Shallow, exposed
Corrib Offshore EIS Enterprise Energy Ireland
APP7.4 - 2 RSK/H/P/P8069/03/04/Appendices Rev01
and very exposed communities at the mouth of the bay are dominated by Laminaria hyperborea forest with an understorey of red algae. In the kelp park at approximately 15 – 25 m, and below the kelp, foliose brown algae (Dictyota dichotoma and Dictyopteris membranacea) and red algae (Delesseria sanguinea) are more dominant. Species richness in the latter zone can be high (up to 72 species). The southern brown algae Taonia atomeria occurs here close to the northern limits of its distribution. Gullies and small cliffs in and below the kelp are dominated by jewel anemones Corynactis viridis and Dead Man’s Fingers Alcyonium digitatum, while small horizontal ledges support foliose red and brown algae. The sheltered reefs east of Ballyglass are distinguished by the presence of mobile boulders and cobbles that are colonised by the kelps Saccorhiza polyschides and Laminaria saccharina. In the outer part of Broadhaven Bay, animal dominated communities occur at depths greater than 23 m. Many of the reefs at these depths are characterised by the Axinellid sponge community which has a wide variety of sponges.
Broadhaven Bay supports an internationally important number of Brent Geese (average peak 292, 1983/84-86/87), as well as regionally important populations of Ringed Plover (234), Golden Plover (103), Dunlin (271), Bar-tailed Godwit (85), Curlew (186) and Redshank (80) - all figures are average peaks for the period 1984/85-1986/87. Two pairs of Common Gulls bred in 1994. Inishderry island holds an important colony of terns; Sandwich Tern (160-170 pairs in 1994), Common / Arctic Terns (28 pairs in 1984; 15+ pairs of Common Terns in 1994), Little Tern (6 pairs in 1984). Black-headed Gulls were also present in 1984 with 150 individuals.
Broadhaven Bay is a fine example of a coastal bay and associated habitats. It contains excellent examples of four habitats listed on Annex I of the EU Habitats Directive and supports a number of unusual marine communities and species. The presence of wintering waterfowl and breeding Terns adds to the importance of the site.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP7.4 - 3
Glenamoy Bog Complex (SAC no. 500)
This very large site is dominated by lowland blanket bog, with significant areas of additional habitats, most notably sea-cliff, coastal heath, machair estuary and shallow bays. Most of the blanket bog within the site lies below an altitude of 150 m and thus is classified as lowland blanket bog, however there are also areas of highland blanket bog. Due to the location of the site, the habitats present are subject to an extreme oceanic influence.
Blanket bog
The vegetation of the lowland blanket bog areas is typically dominated by Molinia caerulea and Schoenus nigricans accompanied by Erica tetralix, Potentilla erecta, Narthecium ossifragum, Potentilla erecta, Eriophorum angustifolium, Rhynchospora alba, Trichophorum cespitosus and various Sphagnum species such as Sphagnum capillifolium, S. papillosum and S. cuspidatum. Well-developed pool areas are frequent and undisturbed islands in some of the larger pools support an unusual shrub community in which the relatively rare Juniperus communis is conspicuous. A noteworthy feature of the blanket bog is the presence of base-rich flushes which, in addition to containing plant species largely absent from ombrotrophic blanket bog, e.g. Carex rostrata, support a number of locally rare plant species such as Vaccinium oxycoccus and the moss Homalothecium nitens. A particularly extensive and well-developed flush system occurs at Rathavisteen.
Coastal habitats
Coastal habitats also occur within this site, however they occupy a relatively small proportion of the site area. Precipitous sea-cliffs, which reach a maximum height of c. 250 m at Benwee Head, dominate the northern fringes of the site. These cliffs contain a typical sea-cliff flora and the exposed cliff tops support wind-shorn heath vegetation which includes Calluna vulgaris, Empetrum nigrum and locally rare species such as Juniperus communis and Arctostaphylos uva-ursi. The cliffs also support large seabird colonies including Storm Petrels, Puffins, Manx Shearwaters, Kittiwakes, Guillemots and Razorbills. In addition to these bird species the cliffs also support Peregrine Falcon and Chough, both of which are listed under Annex 1 of the Birds Directive. A small area of machair occurs at Garter Hill in the north-western corner of the site. Although this area is somewhat degraded and eroded due to overgrazing by sheep, the tightly cropped dune turf does support a large population of Petalophyllum rafsii, a liverwort listed in Annex 2 of the European Habitats Directive. The site also encompasses Sruwaddacon Bay, which is a shallow tidal inlet to the south of Garter Hill and which is a designated Special protection Area under the EU Birds Directive. This bay is of special importance for its wintering wildfowl populations which feed on the intertidal sand/mud flats.
Corrib Offshore EIS Enterprise Energy Ireland
APP7.4 - 4 RSK/H/P/P8069/03/04/Appendices Rev01
General condition of the site
In general the condition of this site is rather poor. Extensive sheep grazing throughout has lead to erosion of blanket bog and dune machair, however damage caused by cattle is also a problem locally. The integrity of many areas of blanket bog in low-lying areas close to roads continues to be threatened by peat extraction and afforestation remains a serious threat.
Erris Head (Natural Heritage Area) (now part of the Glenamoy Bog Complex SAC, Site Code: 001501)
Erris Head is an extensive stretch of rocky sea cliffs on the Mullet peninsula which has been identified as of ornithological importance. This site has been recorded as having a regionally important colony of breeding Great Black-backed Gulls (39 pairs in1970). This site also has recently been identified as an important breeding site for other species, including Choughs, Peregrine Falcons, Ravens, Fulmars and Kittiwakes (D. Strong, pers, comm.). It is also used regularly by small numbers of Barnacle Geese (O. Merne, pers, comm.).
In addition to its ornithological interest, these steep to vertical rugged cliffs along this long strip of coastline contain other habitats of interest including blanket bog and wet grassland on peaty and mineral soils. This area also has excellent scenic value and is a popular amenity area for hikers and visitors.
Grey Seals also occur along this coast and out on some of the inshore locks.
Stags of Broadhaven (Special Protection Area (SPA), Site Code: 000546)
The Stags of Broadhaven are a group of four precipitous rocky islets totally 4 ha. rising to almost 100m, located about 2Km north of Benwee Head. The islets are of ornithological interest, although their relative inaccessibility has made population counts difficult.
Breeding seabirds include:- Leach’s Petrel (200 pairs in 1982), Storm Petrel (< 100 pairs in 1966, numbers unknown in 1982), Puffin (numbers unknown but described as one of the most densely populated colonies in Ireland in 1996), Fulmar (c. 150 pairs in 1969, 45 pairs in 1971), Razorbill (9 pairs in 1971), Herring Gull (c. 25 pairs in 1969) and Kittiwake (c. 25 pairs in 1069).
The Islands are the only known breeding site for Leach’s Petrel (an EU Bird Directive Annex 1 species) in Ireland.
Designated an SPA on 02/11/1995.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP7.4 - 5
Blacksod Bay/ Broadhaven SPA ( No. 037)
This large coastal site, located in north-west Mayo, comprises much of the Mullet Peninsula, the sheltered waters of Blacksod Bay and the low-lying sandy coastline from Belmullet to Kinrovar. The character of the site is strongly influenced by the Atlantic Ocean and the exposed location of much of the site results in a terrestrial landscape dominated by blown sand and largely devoid of trees. The underlying bedrock is principally metamorphic schist and gneiss. The site displays an excellent range of coastal and marine habitats, including several listed on Annex I of the EU Habitats Directive.
Blacksod Bay is 16 km in length and 8 km wide at the mouth. It is a shallow bay, reaching a maximum depth of 19 m and with weak tidal streams. The bay has a good range of representative littoral and sublittoral sediment communities and also infralittoral reefs.
The littoral sediments of the bay consist of areas that are moderately exposed to, or very sheltered from, wave action. Characteristically, exposed to moderately exposed sediment communities are composed of coarse to fine sand and have a polychaete fauna with crustaceans. Species richness increases as conditions become more sheltered. Talitrid amphipods occur in decomposing seaweed on the strand line. Polychaete worms (Arenicola marina), bivalves (Cerastoderma edule) and crustaceans, such as Urothoe brevicornis, Ampelisca brevicornis, and Bathyporeia pilosa, are common in the middle shore.
The sublittoral sediment towards the entrance of the bay is comprised of rather barren medium sand with the occasional bivalve molluscs Glycymeris glycymeris and Ensis spp. Much of the sediment in the centre of the bay is composed of firm, muddy sand with the brittle stars Amphiura spp and the razor shells Ensis spp. Towards the head of the bay the sediment is composed of muddy sand with Turritella communis, Amphiura brachiata and Philine aperta and soft sandy mud with Anthopleura balli and decaying algae. In some areas the sea grass Zostera marina and the reef forming polychaete Serpula vermiculata are frequent. Notable species include Oyster (Ostrea edulis), which occurs at head of the bay, and the sea anemona Phellia gausapata, which is present in the middle of the bay.
Infrallitoral reefs within Blacksod Bay are sheltered or very sheltered from wave action and subject to weak or moderate tidal streams. In sheltered areas that are composed of bedrock, occasional Saccorhiza polyschides overlie a rich assemblage of red algal species such as Dudresnaya verticillata, Heterosiphonia plumosa and Chondria tenuissima. Very sheltered bedrock reef communities are also characterized by foliose red algae. The sea anemone, Metridium senile, is abundant on the tops of the reefs and Antedon bifida on the steeper surfaces. Much of the infralittoral reef in Blacksod Bay is composed of boulders, cobbles and pebbles. The red algae in these areas are sand-tolerant species such as Chondria dasphylla and Gracilaria gracilis. Characterizing faunal species are the anthozoans Metridium senile and Alcyonium digitatum, the hydroid Nemertesia ramosa
Corrib Offshore EIS Enterprise Energy Ireland
APP7.4 - 6 RSK/H/P/P8069/03/04/Appendices Rev01
and the sponge Dysidea fragilis. The purple sea urchin, Paracentrotus lividus, occurs at two sites at the head of the bay.
Large areas of machair, a priority habitat on Annex I of the EU Habitats Directive, are found within this extensive coastal site. On the Mullet peninsula the habitat is best developed to the west of Termoncarragh lake, Tonamace/Macecrump and to the west of Cross Lough. On the eastern shores of Blacksod Bay, extensive areas of Machair occur at Doolough, Srah and Dooyork. The vegetation of the habitat is dominated by plant species of dry dune grassland which include Red Fescue (Festuca rubra), Wild Thyme (Thymus praecox), Daisy (Bellis perennis), Ribwort Plantain (Plantago lanceolata), Selfheal (Prunella vulgaris), Sand Sedge (Carex arenaria) and Lady’s Bedstraw (Galium verum). The main moss species are Brachythecium albicans, Calliergon cuspidatum and Bryum species. In damper areas of machair the vegetation is transitional to fen and contains, in addition to the typical dry machair species, such species as Fairy Flax (Linum catharticum), Cuckooflower (Cardamine pratensis) and Grass-of-parnassis (Parnassia palustris).
Fixed dunes with herbaceous vegetation, another Annex I priority habitat, have an extensive distribution throughout the site and are particularly well developed in the middle and south of the Mullet peninsula, e.g. Emlybeg, Newtown, Agleam. Areas of fixed dunes are typically at their highest c. 500 metres back from the sea and at Emlybeg and Newtown they attain a height of approximately 33 metres. The fixed dunes areas present within the site often form a complex mosaic with other dune habitats such as shifting dunes and machair. Frequent plant species recorded in the habitat include Marram Grass (Ammophila arenaria), Smooth Meadow-grass (Poa pratensis), Wild Carrot (Daucas carota), Common Bird’s-foot-trefoil (Lotus corniculatus), Harebell (Campanula rotundifolia) and Kidney Vetch (Anthyllis vulneraria). The moss cover is well developed and includes Rhytidiadelphus squarrosus, Hypnum cupressiforme, Tortula ruralis and Homalothecium lutescens. The conspicuous lichen Peltigera canina is also occasionally encountered in the vegetation.
Smaller areas of shifting dunes with Marram (Ammophila arenaria) are found in most of the dune areas within the site and typically occur along the most exposed ridges of sand dune systems. The vegetation is species-poor and generally sparse. Along with Marram, typical plant species include Mayweed (Matricaria maritime), Sea Holly (Eryngium maritimum), Colt’s-foot (Tussilago farfara) and the locally rare Sea Bindweed (Calystegia soldanella).
Salt marshes occur in a number of places, notably at Elly Bay, Salleen Harbour, Bunnahowen, Doolough and Gweesalia. Typical species include Thrift (Armeria maritima), Salt-marsh Grass (Puccinellia maritima), Sea Aster (Aster trifolium), Sea Milkwort (Glaux maritima), Sea Rush (Juncus maritimus) and Saltmarsh Rush (Juncus gerardi). At the lower levels of the marshes, and in places extending onto the open sand flats, there occurs Glasswort (Salicornia europaea agg.) and Seablite (Suaeda maritima).
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP7.4 - 7
The site also include shallow freshwater lakes, Termoncarragh Lough, Cross Lough and Leam Lough, the latter two having a brackish influence at times. Marsh and swamp vegetation is well developed around Termoncarragh Lough.
The Annex II liverwort species Petalophyllum ralfsii has been recently recorded from damp areas of machair at Doolough and Dooyork. The Red Data Book plant species Narrow-leaved Marsh Orchid (Dactylorhiza traunsteineri) also occurs.
This site has high ornithological importance, with seven Annex I Bird Directive species occurring regularly in winter and a further two as rare breeders. Blacksod Bay provides ideal habitat for divers (all given accounts are average maxima over the three winters 1994/95 to 1996/97), with Great Northern Diver (64) occurring in numbers of international importance and Red-throated Divers (45) in significant numbers. The site is an important wintering area for an internationally important population of Barnacle Geese (400-500), and also populations of Greenland White-fronted Geese (56) and Whooper Swans (95). Golden Plover are regular in small numbers (c.700), while a nationally important population of Bar-tailed Godwits (552) occur. Little Tern has bred in small numbers in the past, while the site is well known for one of Ireland’s rarest breeding birds, the Red-necked Phalarope. Unfortunately this species may now be extinct as a breeding species.
A wide range of other wintering birds occur. Of particular note are Brent Geese (212) and Ringed Plover (524), both of which have internationally important populations. A further six species have populations of national importance: Common Scoter (642), Red-breasted Merganser (50), Grey Plover (60), Knot (342), Sanderling (58) and Dunlin (2,601). The site is also notable for its breeding waders, with very important concentrations of Dunlin (26 pairs in 1996) and Lapwing (43 pairs in 1996), and significant numbers of Snipe (12 pairs) and Ringed Plover (5 pairs).
High levels of grazing and associated agricultural practices, e.g. feeding of stock and fertilization, has already resulted in locally severe damage to areas of dune and machair. The damage has been intensified by the recent division of dune and machair commonage, which is particularly evident on the Mullet. These agricultural activities remain serious threats. Benthic communities are very vulnerable to bottom-fishing gear such as that used for fishing oysters, and this is thought to be the most damaging to littoral sediment communities if the areas are over-fished.
This site is of high importance for the range of marine and coastal habitats, of which at least seven are listed on Annex I of the EU Habitats Directive, two having priority status. The Annex II species Petalophyllum ralfsii also occurs. It is also of particular ornithological importance, having four wintering species with internationally important populations and also important concentrations of breeding waders.
23.8.1999
Corrib Offshore EIS Enterprise Energy Ireland
APP7.4 - 8 RSK/H/P/P8069/03/04/Appendices Rev01
Blacksod Bay and Broadhaven, Ramsar Site (no. 844)
This Ramsar site has the same boundaries as the Blacksod and Broadhaven SPA.
Site: Blacksod Bay and Broadhaven Designation date: 11/06/1996 Coordinates: 54°03'N 010°00'W Elevation: 0 m Area: 683 ha Location: The site is situated on the western coast of the Mullet Peninsula, near the town of Belmullet on the northwestern coast of Ireland. Criteria: (2c,3b,3c) Blacksod Bay and Broadhaven is important for a range of maritime and coastal habitats. The area holds internationally important numbers of Brent geese Branta bernicla and ringed plover Charadrius hiaticula. Blacksod Bay holds considerable numbers of Haematopus ostralegus, Numenius arquata, Limosa lapponica, Charadrius hiaticula, Tringa totanus, Calidris alpina and C. alba. The site is Ireland's only breeding site for Phalaropus lobatus. Wetland Types: A,E,H,Q (dominance unspecified) The site consists of a sandy sea bay (Blacksod) together with the sheltered inner part of a north-facing sea bay (Broadhaven). It includes considerable stretches of dune systems up the western coast of the Mullet Peninsula. Along the shoreline of Blacksod Bay, saltmarshes occur in sheltered bays and inlets. The site also includes several brackish lakes, i.e. Termoncaragh, Cross Lough and Leam Lough. Biological/Ecological notes: This large area contains a composite of diverse, predominantly marine habitat types. Behind the dunes are extensive areas of dune grassland and machair. These grasslands are of considerable botanical importance. The brackish lakes are important to the breeding waders: Calidris alpina, Gallinago gallinago, Vanellus vanellus and Tringa totanus. The lakes are also important to the wintering wildfowl like Aythya fuligula, A. marila, Cygnus cygnus, Pluvialis apricaria and Branta leucopsis. Hydrological/Physical notes: No information available. Human Uses: No information available. Conservation Measures: The site is an EU Special Protection Area for wild birds. Adverse Factors: No information available.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 7.5: SPECIFICATION FOR BROADHAVEN BAY MONITORING SURVEYS
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP7.5 - 1
Broadhaven Bay Monitoring Surveys
The objective of the surveys will be to monitor for contamination relating effluent discharges to Broadhaven Bay related to the Corrib Field Development. All sampling, analyses and reporting will be carried out in line with internationally accepted practices for such surveys.
Surveys will begin in 2002. The focus of the biomonitoring will be on sedentary or sessile species which are representative of local conditions. In addition chemical and biological characteristics of the sediments will be analysed.
Biomonitoring
Fauna
Cultured oysters or mussels will be kept in cages close to the discharge site of the effluent from the terminal. Cages will be placed both up-current and down-current of the outfall location. The up-current samples acting as controls. The whole body tissue of the molluscs will be analysed twice yearly (spring/early summer and autumn).
Plaice caught in the vicinity of the outfall at the same time that the molluscs are sampled will be analysed. Both muscle and liver tissue will be analysed.
It is anticipated that 20 individuals of each species will be analysed on each sampling occasion at each site. This number will be assessed to ensure that the statistical needs are fulfilled.
Flora
Three nearshore locations will be sampled annually for macro algae (Ascophyllum nodosum being the preferred species).
Parameters to be analysed
All biological samples will be analysed for organic contaminants and trace metals as follows:
Sediments shall be sampled from the area possibly affected by the proposed wastewater outfall. The sampling technique chosen (e.g. box corer, diving) must ensure that the undisturbed top surface layers are taken. The precise sampling pattern will be decided in consultation with both the DOMNR and the EPA when the preferred discharge position is decided. The main sampling axis shall be in the prevailing direction of the effluent plume. The sampling station down stream the outfall should be at 10, 50, 100, 300 and 1000 metres away from the outfall. Sampling positions up-stream and at 90 and 180 degree angle to the main axis should be at 50 and 300 metres.
In addition three (3) stations in the near-shore embayment containing finer sediments shall be sample and analysed
The parameters are described to be analysed are as follows:
Physical parameters (one sample from each stations)
• Visual description and smell
• Total Organic Content (TOC)
• Porosity
• Water content
• Particle size
Chemical parameters (three replicates from each stations)
• Total Hydrocarbon Content (THC)
• Napthalenes, Phenanthrene/Aanthracene, Dibenzothiophene and their C1 – C3- alkylated homologues
• Bicyclic aliphatic hydrocarbons
• PAH according to USA-EPA’s list of 16 compounds
• The metals: As, Ba, Cd, Cr, Cu, Pb, Mn, Hg, Ni, Se, Ag, Zn, Sr and Fe
Biological parameters (five replicates from each station)
• Number of species per 0.5 m2
• Number of individuals per species
• Statistical analysis
The results of the analyses will be reported to both the EPA and the DOMNR. They will also be made available to the local fishing organisations.
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 7.6: CETACEAN SPECIES SIGHTED IN THE VICINITY OF BROADHAVEN BAY
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP7.6 - 1
Cetacean sightings from Broadhaven Bay and adjacent waters (20 within nautical miles), extracted from the Irish Whale and Dolphin Group (IWDG) database.
Record No.
Location Species Date No (s) Behaviour
1 Erris Head Bottlenose dolphin 050601 5 Unknown 2 Benwee head Bottlenose dolphin 030601 10 Unknown 3 Kilcummin Head Harbour porpoise 270501 2 Unknown 4 Annagh Head Minke whale 270501 1 Travelling 5 Achill Island Harbour porpoise 170501 2 Travelling 6 Achill Island Rissos dolphin 170501 3 Travelling 7 Blacksod Harbour porpoise 240301 2 Travelling 8 Achill Island Bottlenose dolphin 240900 3 Unknown 9 Achill Island Killer whale 020700 2 Unknown 10 Benwee Head Killer whale 030600 1 Unknown 11 Downpatrick Head Pilot whale 100899 7 Travelling 12 Offshore Whale sp 200597 2 Bow riding 13 Offshore Common dolphins 211096 10 Unknown 14 Offshore Common dolphins 210796 4 Unknown 15 Inishkea Island Bottlenose dolphin 191195 7 Feeding 16 Inishkea Island Bottlenose dolphin 181195 7 Feeding 17 Blacksod Harbour porpoise 060995 1 Travelling 18 Blacksod Bottlenose dolphin 080495 2 Travelling 19 Eagle Island Small whale sp. 281093 1 Bow riding 20 Achill Island Dolphin sp. 020993 10 Unknown 21 Achill Island Common dolphin 150693 25 Bow riding 22 Achill Island Bottlenose dolphin 100593 12 Unknown 23 Achill Island Humpback whale 151192 20 Unknown 24 Belderrig Rissos dolphin 100792 14 Feeding 25 Achill Island Bottlenose dolphin 220691 30 Travelling 26 Inishkea Island Humpback whale 220584 1 Breaching
Sightings listed in Gordon et al., 2000 are not included in the above table, but are listed in Section 7
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 8.1: CORRIB FIELD AND PIPELINE ROUTE SEDIMENT PHYSIO-CHEMICAL DATA
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP8.1 - 1
FIELD
Summary of Surface Particle Size Distribution and sediment Parameters
nd not detected * The concentration of Chrysene has been included with that of benzo (a) anthracene as the compounds were not fully resolved # The concentration of benzo (k) fluoranthene has been included with that of benzo (b) fluoranthene as the compounds were not fully resolved HS-4B Canadian marine sediment Certified Reference Material Published blished Gardline Data
Enterprise Energy Ireland Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP8.1 - 5
Summary of Heavy and Trace Metal Concentrations (µg/g-1)
Domestic liquid waste water discharges per well (drilling rig and support vessels)
Waste Streams
Generation Rate
Drilling Programme: Total Quantity Discharged (60 d)
Completion Programme: Total Quantity Discharged (25 d)
Well testing: Total Quantity Discharged (25 d)
MODU Sewage & Grey water
0.250 m3 per person per day
1,350 m3 563 m3 563 m3
Putrescible Galley Wastes
0.0003 tonnes per person per day
1.62 tonnes 0.45 tonnes 0.45 tonnes
Service vessels (2)
Sewage & Grey water
0.250 m3 per person per day
360 m3 150 m3 150 m3
Putrescible Galley Wastes
0.0003 tonnes per person per day
0.43 tonnes 0.18 tonnes 0.18 tonnes
(1) Based on the assumption that there will be two service vessels operating in the Corrib Field for the duration of the drilling and completion programmes
Testing programme quantities as for Completion Programme
Cuttings discharges per well Section I
(36”) m3 (tonnes)
Section II (17.5”)
m3 (tonnes)
Section III m3 (tonnes)
Section IV m3 (tonnes)
Total m3 (tonnes)
Dry cuttings
52 (139) 94 (249) 185 (490) 72 (190) 403 (1068)
Mud on Cuttings
156 (187) 40 (144) 79 (116) 31 (39) 306 (486)
Oil on Cuttings
N/A N/A 49 (39) 19 (15) 68 (54)
Assumptions: Washout: 36” well section washes out to 45.5” (60%), 17.5” washes out to 19.25” (21%), 12.25” washes out to 13” (13%), 8.5” washes out to 9” (12%). Rock density of approx 2.65 “oil on cuttings” is the part of the mud which is the organic base fluid, and volumes provided above are those which are theoretically extractable from the “mud on cuttings” Mud and cuttings from sections I and II are discharged direct to seabed Mud and Cuttings from sections III and IV are returned to the shore
Enterprise Energy Ireland Ltd Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP9.2 - 3
MUD CHEMICAL DISCHARGES DURING DRILLING OF IRE 18/25-3
Mud Chemicals
OCNS Class
36" x 30" Section 17.1/2" x 13.3/8" Section
12.1/4" x 9.5/8" Section 8.1/2" x 7" Section Well Testing & Fraccing
Xantham Gum E 0 0 0 Lime E 590 2,436 2,380 1,183 2,970 0 3,619 Soda Ash E 410 590 0 1,000 0
CONTINGENCY CHEMICALS
BW Defoam Green E 0 0 0 Guargum E 0 0 0 Hi Vis CMC E 675 0 675 0 BW Emul Thin S SBM 23 15 23 0 15 BW Envirowash2 D 200 800 4731 0 5,731 0 BW Nutplug E 0 0 0 Calcium Chloride E 0 0 0 Sandseal E 861 2,084 390 861 390 2,084 BW Metacarb E 1,550 4,596 1,633 4,467 3,183 4,467 4,596 Delta P E 0 0 0 Kwikseal E 0 0 0 Sodium Chloride E 9750 1067 68423 130578 78,173 131,645 0 Sodium Bicarbonate E 0 0 0 Citric Acid E 0 0 0 Mica E 0 0 0 Ironite Sponge E 0 0 0
Corrib Offshore EIS Enterprise Energy Ireland
APP9.2 - 4 RSK/H/P/P8069/03/04/Appendices Rev01
COMPLETION FLUID Sodium Bromide E 28814 70303 28814 70303 0 Potassium Chloride E 41353 73878 41353 73878 0 BW Rheodrill D E 350 0 350 0 BW Envirosolv 2 E 770 0 770 0 BW Envirocor 2 E 1468 2184 1468 2184 0
Sodium Metabisulphite E 121 204 121 204 0 BW Biocide D 173 291 173 291 0 Rheopol R E 14 211 14 211 0
WELL CLEAN-UP ADDITIVE BW Envirofloc 2 D 1000 0 1000 0
SUPPLEMENTARY/PRODUCTION CHEMICALS Methanol E 3148 0 3148 0
Monoethylene Glycol E 6069 0 6069 0 CarboProp E 35398 16415 35398 16415 0 1. Barite exceeded 30" limit due to 2 x 10 ppg displacements. 2. In 17 1/2" Section, excess tonnage registered by tank dips designated as discharged. 3. Total Containment system in operation for 12 1/4" and 8 1/2" Sections. The table above provides actual discharges during the drilling of well 18/25-3. It can be assumed that the discharge volumes of mud chemicals for drilling of each of the future wells will be similar. All discharge figures are in kilogrammes.
Enterprise Energy Ireland Ltd Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP9.2 - 5
CEMENT CHEMICAL DISCHARGES DURING DRILLING OF IRE 18/25-3
Cement Chemicals
OCNS Class 30" Conductor 20" x 13.3/8" 9.5/8" Well testing
& Fraccing
Suspension – 2 ×
Cement Plugs
Cumm. Actual Material Left
Downhole
Cumm. Actual Total Discharge
a b c d e f g h i j a+c+e+g+i b+d+f+h+j
Left In Hole
Discharge to sea
Left In Hole
Discharge to sea
Left In Hole
Discharge to sea
Left in hole
Discharge to sea
Left in hole
Discharge to sea Kgs Kgs
Calcium Chloride E 1,538 431 1,538 431 Sodium Chloride E 1,872 990 1,872 990 Retarder E 552 549 189 69 14 1,170 203 Barite E 0 0 Bentonite E 0 0 Surfactant C 712 187 712 187 Cement Rugby Class G E 35,591 1,409 93,330 1,000 83,051 6,949 12500 500 224,472 9,858 Retarder C 0 0 Defoamer E 68 20 76 78 37 11 4 233 61 Dispersant C 150 764 182 42 5 956 187 Mudpush XL B 0 0 Anti Settling Agent E 0 0 Retarder E 47 11 10 58 10 Silica Flour E 0 0 Extender E 2,362 1,113 341 3,475 341 Mutual Solvent E 0 0 Sea Dye E 25 25 50 0 Gasblock D 0 0 UNIFLAC E 2,782 1,028 2,782 1,028
BF-10LE E 996 551 996 551 BF-7L E 6970 1703 6970 1703 D-4G D 38 0 38 D-4GB E 3855 1038 3855 1038 FP-9L B 248 59 248 59 GBW-5 C 31 7 31 7 GW-4 AFG E 7407 4464 7407 4464 High Perm CRB C 13 3 13 3 XCIDE 102 D 532 448 532 448 XLW-56 D 3500 856 3500 856 XCD Polymer E 29 0 29 FRW-14 B 244 0 244 CI-27 C 170 0 170 TOTAL = 260,870 TOTAL = 22,906
Enterprise Energy Ireland Ltd Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 9.3: WATER TREATMENT FLOWCHART
Enterprise Energy Ireland Ltd Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 10.1: DESCRIPTION OF ATMOSPHERIC POLLUTANTS
Enterprise Energy Ireland Ltd Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01 APP10.1 - 1
Oxides of Nitrogen
Oxides of nitrogen are produced as a result of combustion processes, such as flaring. The term ‘NOx’ is often used to mean a mixture of nitrogen monoxide (NO) and nitrogen dioxide (NO2). It is nitrogen dioxide (NO2), which is associated with adverse effects on human health. NO2 may have both acute (short term) and chronic (long term) effects on health. Certain individuals within the general population are particularly susceptible to elevated NO2 concentrations (e.g. people with asthma). At relatively high concentrations, NO2 causes inflammation of the airways. Long-term exposure may effect lung function and enhance the response to allergens in sensitised individuals. NO2 is also, indirectly, a greenhouse gas as it is a primary precursor of ozone.
Carbon Monoxide
Carbon monoxide (CO) is formed as a result of incomplete combustion of carbon-containing fuel. Human exposure to certain levels of carbon monoxide has been demonstrated to result in negative health effects. Certain individuals within the general population are more sensitive to the effects of elevated levels of CO than others. Sensitive individuals include those who have an existing disease that affects delivery of oxygen to the heart or the brain (e.g. coronary artery disease). Motor vehicles are the largest contributors to emissions of CO in most countries.
Sulphur Dioxide
Sulphur dioxide is formed as a result of the oxidation of sulphur impurities in fuel during and after combustion. Health effects include constriction of the airways (asthmatics are particularly vulnerable). Sulphur dioxide is also the primary cause of acid rain.
Volatile Organic Compounds (VOCs)
The term VOC encompasses a large range of compounds. VOCs are involved in the formation of ground level ozone and in depletion of the ozone layer. They also contribute to the greenhouse effect in that methane and photochemical oxidants produced from the use of VOCs are both greenhouse gases. They therefore have both local and regional / transboundary effects.
Carbon Dioxide
Carbon dioxide is a non-toxic, odourless, colourless gas. It is generally not hazardous to the local environment in the short term but on a global scale it is considered to be the largest single contributor to the greenhouse effect, despite being the least harmful of the major greenhouse gases per unit volume. The major source of CO2 in Ireland is the burning of fossil fuels, mainly for power generation. Carbon dioxide and global warming potential are discussed in Chapter 13.
Corrib Offshore EIS Enterprise Energy Ireland
APP10.1 - 2 RSK/H/P/P8069/03/04/Appendices Rev01
Methane
Methane is unlike the other pollutants described in this section as its major source is not fuel combustion. Sources include agriculture (particularly enteric fermentation in cows) and leakage from the gas distribution system. In sufficient concentrations, methane presents an explosion hazard but, in terms of industrial emissions, the major threat is global warming. Methane has a GWP factor of 21, meaning that a unit volume has 21 times the global warming potential of the same volume of CO2. Methane and global warming potential are discussed in Chapter 13.
Ozone
Ozone is not emitted directly from any man made source in any significant quantities. It arises from chemical reactions in the atmosphere triggered by sunlight. In the stratosphere, ozone has a beneficial role, shielding the earth from harmful ultra-violet radiation. It is formed by the action of sunlight on oxygen molecules, initially. In the stratosphere, the balance between ozone and oxygen is disturbed by the upward migration of ozone-depleting substances such as chlorofluorocarbons (CFCs). This causes a reduction in ozone levels and thus allows more ultra-violet radiation to reach the earth’s surface.
In the lower layers of the atmosphere, ozone is formed primarily by a series of complex reactions, occurring over several hours or even days, between VOCs and oxides of nitrogen (NOx), initiated by sunlight. Both VOCs and NOx are produced from combustion and other industrial processes and are the most important precursors of ozone in the lower atmosphere, where ozone acts as a greenhouse gas. Acute health effects have also been observed - irritation to the eyes and nose and minor changes to the airways can occur at sufficient concentrations.
Enterprise Energy Ireland Ltd Corrib Offshore EIS
RSK/H/P/P8069/03/04/Appendices Rev01
APPENDIX 14.1: MARINE ARCHAEOLOGY REPORT, AS SUBMITTED TO DUCHAS
