Appendix L Method Statements.pdf

CORRIB FIELD DEVELOPMENT PROJECT

Onshore Works – Glengad

METHOD STATEMENT Rev 01 LVI, GLENGAD COMPOUNDS and ACCESS ROAD CONSTRUCTION

Shell Exploration and Production Ireland Ltd. Title: LVI, Glengad Compounds and Access Road

Draft Environmental Management Plan Document No: COR‐14‐OP‐SH‐0000 EMP Method Statement Revision: 01 Page 2 of 8

SUMMARY

The construction of the Landfall Value Installation (LVI) within a dished area will be facilitated by the establishment of a construction compound. This compound will also facilitate the onshore works associated with the umbilical installation, onshore pipeline construction, and pipeline commissioning. A second compound will be established to construct the reception shaft for the Tunnel Boring Machine (TBM)1. A permanent access road to the LVI will also be constructed.

PURPOSE This method statement defines the method for the construction of the LVI, establishing the Glengad construction compounds and permanent LVI access road at Glengad.

LOCATION Glengad Headland. The temporary working area from chainage 83.38 – 83.92 lies within the Glenamoy Bog Complex candidate Special Area of Conservation (cSAC) Site Code 0000500 and is adjacent to the Blacksod Bay/Broadhaven proposed Special Protection Area (pSPA) Site Code 004037. The northern section of the access road from the L1202 is also in the cSAC.

HABITATS / CONSERVATION STATUS

The habitats located within the temporary working areas at Glengad comprise improved agricultural grassland and improved wet, rushy grassy grassland, neither of which are EU annexed habitats.

With the exception of the southern section of the reception shaft compound, these habitats are located within the cSAC.

TIMESCALE

The entire work scope will take approximately 26 months. The LVI construction compound will be in operation for the entire duration of the onshore pipeline construction including LVI surface water outfall pipe installation, LVI construction, Umbilical pull‐in, onshore pipeline construction, tie‐in of the onshore and offshore pipeline and final commissioning activities.

TECHNIQUE Establishment of Glengad Compounds

The compounds will be installed as follows:

• A 3m high palisade fence will be erected on grassland and secured by concrete road barriers.

• In designated sections the perimeter fence will be screened with a suitable solid board to visually and acoustically screen the works in order to minimise disturbance to birds and non‐avian fauna.

• A palisade fence fixed to precast concrete slabs will be positioned on the foreshore to facilitate the LVI outfall pipe installation. This fence will be removed upon reinstatement of the cliff face and replaced with a land based fence installed along the top of the cliff.

• The temporary fences around the construction compounds and the LVI will be mammal proof.

• A temporary access road and hardstand areas will be constructed using locally sourced imported gravel/stone.

• Temporary welfare facilities will be installed on prepared ground separate from the main working areas. Containers will be positioned as required within the compound.

• All necessary electrical/telecom wiring, site services, lighting, piping, ducting and fixtures will be installed.



Earthworks and Civil Works

• Topsoil will be stripped from LVI location and stockpiled in a designated location separate from sub soil and other excavated material.

• The dished area will be excavated, and the material stockpiled separate to topsoil.

• Individual LVI structures within dished area will be excavated. • Construction of LVI structures, pipeline and ancillary services installation

will be completed simultaneously. • Once all installation, inspection and testing has been completed, all

structures will be backfilled to their designated finished levels. • Permanent fencing and associated security systems will be erected. • Topsoil will be placed on new embankment slopes. An open mesh

biodegradable textile (GeoJute) maybe used on the slopes surrounding the LVI to stabilise topsoil against erosion.

LVI Mechanical , Electrical and Commissioning works

• The piping, valves, structures, and chambers will be erected on the prepared LVI foundations.

• The relevant LVI components will be welded/jointed and inspected. • The offshore pipeline will be connected to the LVI. • The required LVI and pipeline commissioning, including hydrotesting, will

take place within the construction compound.

Offshore Umbilical Installation (Onshore Works)

• The compound will also be used to support the offshore umbilical pull ashore.

• Prior to the pull ashore a winch base will be constructed and winch installed. This winch will be used to pull the offshore umbilical line through the existing umbilical conduit to a termination point onshore at the LVI.

• Following the pull ashore the umbilical will be monitored and tested during offshore installation.

• Following the offshore lay of the umbilical, the onshore winch and base will be removed and area reinstated.

Reinstatement

The compound will not be reinstated until the end of the construction period however, some reinstatement will take place prior to this if progress allows. In general, reinstatement will progress as follows:

• Excess materials from the excavation of the LVI “dished” area will be reused elsewhere if possible and the surplus removed to a licensed waste facility.

• Construct permanent access road to LVI using the specified mix of stone and soil.

• Remove temporary facilities.

• The site will be reinstated using the stockpiled topsoil and vegetation will be allowed to regenerate naturally. No seed will be imported.

• All drains will be reinstated to their previous condition or, as agreed with



the relevant parties.

• Where appropriate, simple, surface gravel field drains will be put in place to prevent water logging.

• The temporary palisade fencing will then be removed off site and stock proof fencing will be erected to protect the reinstated areas.

EQUIPMENT/MATERIALS Excavators

Articulated flatbeds and tipper trucks

Front tipping trucks

Temporary welfare cabins

Palisade security fence

Winches and hydraulic power packs

Hydrotest equipment

Cranes and lifting equipment

Side booms

Concrete pump

Electrical tools

Welding equipment

Synthetic fabrics

Commissioning plant and equipment

Storage tanks

RESTRICTIONS Some sections of the temporary working area lie within the Glenamoy Bog Complex Complex cSAC and adjacent to the Blacksod Bay/Broadhaven BaypSPA

• General working hours are restricted to between 07:00 – 19:00 weekdays and 07:00 and 16:00 Saturday.

• Noise and vibration limits • Lighting constraints

CONTINGENCY • Excavated material may have to be screened for potential reuse.

1 See Tunnelling Operations and Reception Shaft Method Statements

Shell Exploration and Production Ireland Ltd. Title: LVI , Glengad Compounds and Access Road

Draft Environmental Management Plan Document No: COR‐14‐OP‐SH‐0000 EMP

Method Statement Revision: 01 Page 5 of 8

POTENTIAL ENVIRONMENTAL IMPACT

MITIGATION

Noise, vibration and lighting Disturbance.

• Noise and vibration will be minimised through design, and appropriate section of plant and machinery.

• Proactive maintenance of plant and equipment.

• Cladding of stationary machinery such as generators.

• A 3m high non‐transparent noise barrier will be installed in designated places around the perimeter of the construction compounds to prevent disturbance to birds in the pSPA .

• Mobile and fixed site lighting will be designed to limit light spillage.

Increased dust levels • Roads/working area will be dampened down, as required to ensure dust levels due to construction activities are kept to a minimum.





MITIGATION

Damage to habitats, including cSAC habitats

Access Road

• The sod bank which forms the boundary on the eastern side of the access road (from the public road) will be fenced off to protect it from damage during construction. Any temporary widening of the access road will be done on the western side.

LVI and Glengad Compounds

• An earthen (sod) bank forms the cSAC boundary to the south of the temporary working area adjacent to the LVI and onshore pipeline temporary working area. This sod bank will be fenced off to prevent construction activities encroaching on it.

• Fencing will be put in place to protect the Annex 1 habitats located to the north of the compounds.

• No seed will be imported in order to prevent the pollution of the native gene pool by alien genotypes.

• The top soil removed from the footprint and compounds will be carefully stored (separately from the sub‐soil).

• Following construction this topsoil will then be used on the areas to be reinstated, including the slopes of the LVI and they will be left to re‐vegetate naturally.

• To aid topsoil stability and vegetation regeneration, an open mesh geotextile membrane (GeoJute) may be laid on the side slopes of the LVI excavation.

• Surface drainage will be put in place at the time of reinstatement to prevent water logging where appropriate.

• Stone used will be locally sourced.





MITIGATION

Disturbance to Birds

Ground nesting birds

• Prior to construction, the temporary working area will be mowed in order to discourage ground nesting birds from attempting to breed on the temporary working area.

• A walkover survey will be undertaken prior to construction in order to ensure that no ground nesting birds are present on lands to be disturbed.

Sand Martin

A Sand Martin colony is located in the soft cliffs to the north and north east of the landfall at Glengad. Mitigation measures as outlined below will be put in place.

• An exclusion zone will be defined above and behind the colony such that no construction activities affect the existing burrows or threaten the stability of the cliff in which the burrows are situated.

• Apart from specialists conducting monitoring, no personnel, traffic or construction activities will be permitted between the temporary fencing and the cliff‐top directly above the colony.

• Soil stockpiles will be covered where necessary with a fine mesh netting to prevent sand martins from making nest burrows therein.

• Lighting in site compounds will be directed downwards and be designed to minimise light spillage outside the working area.

pSPA

• Visual and acoustic screening will be placed on the palisade fence in designated places to prevent disturbance to birds in the pSPA.

• Lighting will be directed downwards and be designed to minimise light spillage outside the working area.





MITIGATION

Construction activities may have negative impact on local wildlife (otters and badgers etc).

• The palisade fence around the LVI and reception shaft compounds will be mammal proof.

• The remainder of the fencing demarking the temporary working area, including the access road, will have mammal gates at the base at 75m intervals. These will allow mammals (otters and badgers etc) free access across, and a means of escape from, the temporary working area.

• During construction ramps will be provided at open trenches to provide a means of escape for otters and badgers and other wildlife.

Pollution of terrestrial / aquatic habitats due to spillage or leaks of oil/diesel from plant and equipment.

• Machinery and plant will be inspected prior to mobilisation to site.

• Refuelling of plant/machinery will take place in designated areas only.

• Spill kits will be available on site

Release of suspended solids from the works may have negative impact on water quality.

• The LVI surface water outfall pipe will not be used for dewatering of excavations.

• A surface water management system will be utilised to ensure removal of suspended solids prior to discharge to receiving waters at an agreed location.


Visual impact from the LVI structure.

• The LVI will be constructed in a dished area to reduce visual impact of structure.

Earthworks may disturb archaeological remains.

• A licensed archaeologist will be on site to monitor all excavations in previously undisturbed areas.



METHOD STATEMENT Rev 01

LVI Surface Water Outfall Pipe and Cliff Reinstatement

Shell Exploration and Production Ireland Ltd. Title: LVI Surface Water OutfallDraft Environmental Management Plan Document No: COR‐14‐OP‐SH‐0000 SEPIL EMP


SUMMARY

The Landfall Valve Installation (LVI) Surface Water Outfall will be constructed by excavating a trench and installing the pipe, headwall and gabion basket structure within the cliff face. The cliff face will be subsequently reinstated and the outfall pipe trench backfilled with excavated material.

PURPOSE This document defines the method for installation of the LVI surface water outfall pipe and subsequent reinstatement of the cliff section at Glengad.

LOCATION Glengad Headland. The temporary working area from Chainage 83.38 – 83.50 lies within the Glenamoy Bog Complex candidate Special Area of Conservation (cSAC) and the Blacksod Bay/Broadhaven proposed Special Protection Area (pSPA).


Habitats comprise non‐annexed improved agricultural grassland (cliff top), reinstated sedimentary cliff; upper shoreline; and non‐qualifying intertidal Annex I habitat (1140 ‐ Mudflats and sandflats not covered by sea water at low tide).

TIMESCALE

The works will take approximately 8 weeks to complete, timed so that the works associated with the cliff face will be undertaken between April and September. This is to avoid disturbance to feeding Brent Geese during the overwintering period. The remaining works will take place outside this time period.

TECHNIQUE LVI Outfall Pipe Trench and Cliff Excavation

• Temporary site palisade fencing will extend through the cliff cut and extend onto a limited section of the foreshore (Ch 83.38 approximately).

• A trench will be excavated from the cliff face and material will be stored temporarily within the Glengad compound for reinstatement. This material will also be used to form a suitable access ramp onto the foreshore for the installation of the surface water outfall pipe.

• The excavation of the trench in the cliff face may be up to 5.5m in depth and up to 15m wide. All trench arisings will be temporarily stored in the Glengad compound.

• The trench will be excavated towards the LVI, sloping trench sides as necessary.

• In sections of restricted working area or where ground conditions are poor, the surface water outfall pipe will be laid using a trench box or support structure.

Installation of Pipe Headwall and Gabion Basket Structure

• The headwall will be constructed by means of hand filled gabion baskets around the outfall pipe blended in to the existing cliff face.

• A geotextile separation layer will be placed at the base of the cliff face, on top of which a headwall will be constructed using gabion mattresses and baskets.

• The baskets will be filled with locally sourced stone to maximise the integration of the headwall with the existing cliff and surrounding environment.



• The area in front of the headwall will be reinstated with locally sourced stone chosen to maximise the integration of the outfall with the existing cliff and surrounding environment.

Installation of LVI surface water outfall pipe

• The LVI surface water outfall pipe will be placed in sections and joined in the prepared trench.

• The LVI surface water outfall pipe will be backfilled after testing. • The backfill material shall consist of compacted fine material with

progressive layers of excavated material being utilised to complete trench backfill.

Cliff and Trench Reinstatement

• The cliff face will be reinstated once the outfall pipe installation has progressed an adequate distance from the cliff to enable full cliff reinstatement.

• As the gabions are installed the cliff material will be compacted in layers progressing to original ground level. The subsoil will be graded to reflect the original contours of the headland.

• Geotextile may be required on steep sections of the cliff to prevent wind erosion and silt run off.

• The foreshore area will be reinstated to the highest achievable standard with maximum reuse of original foreshore material.

• Surplus foreshore material will be reused or disposed of at a licensed facility.

• Any surplus imported rock will be removed off‐site for reuse. • The temporary fencing will be removed from the foreshore during cliff

reinstatement. • A stock proof fence will be erected on the cliff top for protection of

people and livestock.



EQUIPMENT/MATERIALS Excavators

Articulated tipper trucks

Front tipping trucks

Cranes

Welding Equipment

Pallisade Fencing

Surface Water Outfall Pipe

Gabian Baskets and locally sourced stone

Synthetic fabrics

RESTRICTIONS The working area lies within the Glenamoy Bog Complex

Blacksod Bay/Broadhaven Bay cSPA 4037

• Normal working hours are restricted to between 07:00 – 19:00 weekdays and 07:00 and 16:00 Saturday.

• Noise and vibration limits Lighting constraints.

CONTINGENCY A rock breaker mounted on an excavator, maybe required to achieve the required depth for the LVI outfall pipe or the LVI outfall pipe termination gabion installation.




MITIGATION


• Noise and vibration will be minimized through design, and appropriate selection of plant and machinery .

• Proactive maintenance of plant and equipment.


• Screening will be placed on the palisade fence in designated places to prevent disturbance to birds in the pSPA.



Damage to habitats in the cSAC and pSPA

• No machinery or personnel will be permitted outside the temporary fencing on the foreshore with the exception of specialists who are conducting monitoring / survey work.

• Works will be restricted to the section of cliff which was reinstated in 2009. Fencing will protect the previously undisturbed cliff on either side of the currently reinstated section of cliff.

• Sediment / pollutant run off control measures (see below) will be implemented to minimise impact on shoreline, intertidal and marine habitats.

• Imported stone, including that used for cliff reinstatement, will be locally sourced.

Construction activities may have negative impact on local wildlife ‐ otters and badgers.

• Pre‐construction surveys for otters and badgers will be undertaken within 1‐3 months prior to construction. The areas to be included are approximately 50‐100m either side of the centre line of the pipeline for otters, and 30m either side of the centre line for badgers.

• Wildlife will be excluded from the temporary works area by means of mammal proof fencing.




MITIGATION

Disturbance to Birds and the pSPA


• Prior to construction a walkover survey will be undertaken to check for ground nesting birds and the temporary working area onshore will be mowed to discourage these birds.


Sand Martin



• Apart from specialists conducting monitoring, no personnel, traffic and construction activities will be permitted between the Temporary Working Area fencing and the cliff‐top directly above the colony.

• A wide foreshore exclusion zone will be in place to prevent any activity on the foreshore below and in front of the burrows which may deter normal behaviour and could result in lowered breeding success.


• Lighting will be directed downwards and designed to minimise light spillage outside the working area.

• Acoustic & visual screening of construction activities will be in place.




MITIGATION

Brent Geese

Brent Geese over winter in the pSPA from October to the end of April and feed on algal beds adjacent to the Glengad landfall site.

• Construction activities for the LVI outfall, including cliff reinstatement works will be carried out during summer months and outside the overwintering period.

Pollution of terrestrial / aquatic habitats due to spillage or leaks of oil/diesel from plant and equipment.



• Refuelling will not take place on the foreshore.

• Spill kits will be available on site.

Release of suspended solids from the works could have negative impact on water quality.

• As much as possible, construction works associated with the cliff cut will be carried out during low tide or neap tides to prevent inundation and subsequent mobilisation of sediment into the marine environment.

• In drain mitigation will be placed as required to reduce silt impact on associated surface waters.

• The LVI surface water outfall will not be used for dewatering of excavations during construction works.


• Pumped water will be subject to sediment control measures.

Earthworks may disturb archaeological remains





ONSHORE PIPELINE CONSTRUCTION (Glengad)

Shell Exploration and Production Ireland Ltd. Title: Onshore Pipeline Construction Glengad Draft Environmental Management Plan Document No: COR‐14‐OP‐SH‐0000 SEPIL EMPMethod Statement Revision: 01 Page 1 of 6

SUMMARY

This method statement outlines the methodology for the construction of onshore gas pipeline and services from the tie in of the offshore pipeline to the Landfall Valve Installation (LVI) and from the LVI to the tunnel reception pit.

PURPOSE This method statement defines the methodology for construction of the pipeline and services in Glengad, to include preparation of the pipeline temporary working area, pipeline installation and reinstatement.

LOCATION Glengad Headland, between chainage 83.49 and 83.86. Most of the temporary working area is within the Glenamoy Bog Complex candidate Special Area of Conservation (cSAC). It is in close proximity to the Blacksod Bay/Broadhaven proposed Special Protection Area (pSPA).


The habitats located within the temporary working areas at Glengad comprise improved agricultural grassland and improved wet, rushy grassy grassland, neither of which are EU annexed habitats.

With the exception of a short section of the pipeline route, these habitats are located within the cSAC.

TIMESCALE

Preparation of the temporary working area and construction of the pipeline are expected to take approximately two months. It should be noted that the temporary working area will remain fenced off until the completion of tunnelling operations to facilitate removal of the tunnel boring machine (TBM) and to allow connection of the pipe within the tunnel to the pipe laid onshore.

TECHNIQUE Temporary Working Area Preparation

• The temporary working area will be fenced off using 3m high palisade fencing.

• In designated sections on the northern side of the works, the perimeter fence will be screened with a suitable solid board to provide a visual and acoustic screen.

• Topsoil within the temporary working area will be stripped and stockpiled onsite. Subsoil will be stockpiled separately.

• Any earthen (sod) banks to be impacted will be carefully dismantled with the surface sods being stored separately and maintained during construction. Those earthen (sod) banks which do not require to be dismantled will be fenced off to protect them from construction traffic.

• A running track, consisting of geotextile overlaid with materials excavated during LVI construction and/or locally sourced stone, will be constructed to allow access for construction plant.

• Drains within the temporary working area will be identified by marker posts

• Interceptor drains and flume pipes will be installed, as necessary, to isolate and divert surface water arising off site to receiving waters.


• Limited access across the temporary working area for landowners will be provided for by agreement with the landowner and when construction works allow safe access.

Pipeline Construction

• All pipelines will be strung out, welded and tested prior to excavating the trench.

• The pipeline trench will be excavated and the material stockpiled onsite. Should any distinct layers in the subsoil be encountered, they will be excavated and stockpiled separately.

• The excavated trench will be dewatered if required, from a sump box at the lowest point.

• The pipe sections will be lowered into the trench by means of side booms and inspected and backfilled with selected imported material. The main body of the trench will be backfilled with materials excavated from the trench. All soil layers will be reinstated in reverse order to the manner in which they were excavated.

Reinstatement As stated previously, the temporary working area and running track will be maintained until after completion of the tunnel and associated tie‐in works. Some reinstatement of the pipeline trench may be permitted after pipeline installation. Final reinstatement will be as follows; • The temporary running track will be removed off site for re‐use, if

appropriate and its route reinstated.

• The site will be reinstated using the stockpiled topsoil and vegetation will be allowed to regenerate naturally. No seed will be imported.

• All drains will be reinstated to their previous condition or as agreed with the relevant parties.

• Where appropriate, simple, surface gravel field drains will be put in place to prevent water logging.

• Earthen (sod) banks will be fully reinstated.

• The temporary palisade fencing will then be removed off site and stock proof fencing will be erected to protect the reinstated areas.

Note: All movement of materials will be through the Glengad compound entrance.


EQUIPMENT Excavators

Articulated Dumptrucks

Tracked Dumpers

Side booms

RESTRICTIONS Some sections of the temporary working area lie within the Glenamoy Bog Complex Candidate cSAC and are adjacent to Blacksod Bay/Broadhaven Bay pSPA.

• Construction works will be sequenced to facilitate the early commencement of reinstatement works if possible.

• Normal construction work is restricted to between 07:00 – 19:00 weekdays and 07:00 and 16:00 Saturday.

• Noise and vibration limits. • Lighting constraints.



MITIGATION


• Noise and vibration will be minimised through design, and appropriate selection of plant and equipment.

• Proactive maintenance of machinery to minimise noise and vibration.


• Acoustic screening & fencing to minimise noise.

• Site and mobile lighting will be designed to limit light spillage.


Damage to habitats, including those in the cSAC

• Fencing will be put in place to protect the Annex 1 dune grassland located to the north of the proposed pipeline route.

• The top soil removed will be carefully stored (separately from the sub‐soil) in order to maintain the seedbank.

• No seed will be imported to prevent pollution of the native gene pool by alien genotypes.

• Sod banks impacted by construction will be carefully dismantled and reinstated by hand.



MITIGATION

Disturbance to Birds and the pSPA


• Prior to construction, the temporary working area will be mowed in order to discourage ground nesting birds from attempting to breed on the temporary working area.


Sand Martin



• Apart from specialists conducting monitoring, no personnel, traffic or construction activities will be permitted between the fenced temporary working area and the cliff‐top directly above the colony.



pSPA

• At the northern side of the pipeline works, visual and acoustic screening will be placed on the palisade fence in designated places to prevent disturbance to birds in the pSPA.




MITIGATION

Construction activities may have negative impact on local wildlife.

• Pre‐construction fauna surveys will be undertaken within 1‐3 months prior to construction, including for otters and badgers. The areas to be included for these two species are approximately; 50‐100m either side of the centre line of the pipeline for otters, and 30m either side of the centre line for badgers.

• During construction, ramps will be provided at open trenches to provide a means of escape for otters and badgers and other wildlife. Mammal gates will be provided at the base of the fencing at 75m intervals to allow otters and badgers free access across, and a means of escape from the Temporary Working Area.

Pollution of terrestrial and aquatic habitats due spillage or leaks of oil/diesel from plant and equipment.




Release of suspended solids from the works may have negative impact on water quality.

• The LVI outfall will not be used for discharge from dewatering of excavations during construction works.




Earthworks may disturb archaeological remains.



Onshore Works – Aughoose


Aughoose Compound Construction

Shell E&P Ireland Ltd. Title: Aughoose Compound Construction

Draft Environmental Management Plan Document No: COR-14-OP-SH-0000 SEPIL EMP


SUMMARY

The works involve the erection of security fencing, site enabling works and all associated works to facilitate

the erection and construction of various temporary structures required to service the tunnelling

operations and subsequent pipeline installation.

PURPOSE This method statement outlines the general method and sequence for installation

of all temporary structures and services required for tunnelling. Actual tunnel

operations and launch shaft construction is detailed elsewhere.

LOCATION Aughoose Compound, pipeline chainage 88.67 to 89.11. The Aughoose Compound

is adjacent to the Glenamoy Bog Complex cSAC (Site Code 000500) and the

Blacksod Bay/Broadhaven pSPA (Site Code 004037).

HABITATS /

CONSERVATION

STATUS

Habitats comprise non-annexed modified blanket bog habitats, eroding blanket

bog and cutover. They do not form part of any designated conservation site.

TIMESCALE

Approximately 6-8 months to construct the compound which will be operational

for a further 20 months depending on seasonal reinstatement. Construction of a

2nd

entrance (Access B) will take place approximately 10 months after the main

entrance is constructed.

TECHNIQUE The construction of the temporary compound comprises a number of main

construction operations; security fencing, entrance road construction, services

installation, initial welfare area construction, peat/stone handling area

construction, peat stockpiling, shear key construction, settlement pond

construction, site drainage installation, bulk earthworks, flexible pavement

construction, rigid pavement construction, retaining wall construction and

acoustic barrier construction. These operations are completed generally as

follows;

Security Fencing

• A 3m high palisade fence is to be erected along the site boundary with the

L1202. This will involve a period of temporary traffic control to facilitate

this operation. All traffic control measures will be in accordance with

Chapter 8 of the Dept. of Transport Traffic Signs Manual and will be of

short duration.

• A 3m high palisade fence situated on bog mats will be used where the site

boundaries are on peat (east, north and western sides).

• In designated sections, the perimeter fence will be fitted with a suitable

solid board liner to visually and acoustically screen the works in order to

minimise disturbance to birds in the pSPA and otters on shorelines and

along the Leenamore River.

Entrance Road Construction

• The site entrance road will be constructed using the stone road method of

peat replacement/displacement with selected imported locally sourced

stone.

• The stone road will consist of a peat stone matrix (approximately 0.5m of

peat left insitu with a 300mm to 500mm single size stone pushed into it,




forming a peat stone matrix).

• Starting at the L1202 (incorporating the traffic control measures in

Chapter 8 of the Dept. of Transport Traffic Signs Manual) the road

construction will proceed northwards into the site.

• All excavated peat will be placed directly into the peat storage area and

spread as required.

• The initial 50m will consist of a widened site entrance to facilitate the

correct sightlines and a double gate security system for deliveries, visitors,

etc.

• The entrance road will be widened inside the 2nd

access gate to allow

laden vehicles turn around once they have passed through the gate. This

widened area will be removed once the entrance road opens out into the

peat handling area.

• The stone road construction operation will also involve a temporary

surface water treatment system involving the construction of lined v*

shaped drainage channels, temporary settlement lagoons and a mobile

settlement/treatment unit. All surface water runoff from the stone road

construction will flow through the water treatment system prior to

discharge to the existing surface water ditch.

• A secondary entrance (Access B) will also be constructed using a

temporary bog mat access from the peat handling area. A temporary

ramp will be installed to allow vehicular access from Access B onto the

L1202. For the initial construction phase of the project, Access B will only

be used in the case of emergency.

* V-ditches will be lined with impermeable high density polyethylene (HDPE) liner.

Services Installation

• Trenches will be excavated within the site roads to facilitate the

installation of a surface water collection system, a watermains and

ducting for temporary power and telecoms.

• All services will be installed to relevant engineering standards using an

open trench method in the installed stone road.

• Services will be continuously tested and backfilled as excavation

progresses using the same materials excavated.

Peat/Stone Handling Area

• In order to facilitate the export of peat to Srahmore a specific vehicle

turning and loading area (peat/stone handling area) will be constructed to

separate road traffic from site traffic.

• Peat excavated from various locations of the site will be transported to

this location.

• Peat suitable for stockpiling will be separated from peat which is to be

transported to Srahmore.

• Part of this area will also be used for stockpiling stone used in




construction operations.

• A wheel wash facility will be installed in this area.

Initial Welfare Area Construction

• The initial welfare area and materials laydown area will be constructed

within the peat handling area on the north-west side of the main access

road.

• Welfare facilities will consist of toilets, offices, drying rooms, storage

containers, waste compactors and skips, canteens and bunded chemical

stores.

Peat Stockpiling

• The peat from the surface of the site (generally 0.6 m), including the

surface vegetation, will be stockpiled onsite for reinstatement after

tunnelling completion.

• It should be noted that an additional quantity of peat will be stored onsite

for reinstatement of locations where mineral soil will be excavated.

• Peat stockpiling will involve the construction of a temporary bog mat

access into the designated areas.

• Peat stored in the peat handling area will be transferred to the peat

storage area.

• The vegetation layer will be placed (roots downwards) on top of the stored

peat so that it can continue to grow during storage and be available for

subsequent reinstatement.

• The bog mat access will be removed as the area fills and will be reinstalled

again during reinstatement operations.

Shear Key Construction

• In order to mitigate against geotechnical risks associated with peat

excavation (e.g. slippage of peat), a shear key will be installed around the

perimeter of the tunnelling compound by means of the stone road

method.

• This will be completed prior to any excavation of the main body of peat

from the tunnel compound.

• Peat excavated during shear key construction will be brought to the peat

handling area prior to stockpiling in the peat storage area or transport to

Srahmore.

Settlement Lagoon Construction

• Prior to excavation of the main body of peat (bulk earthworks), a

settlement lagoon will be constructed at the low point of the site.

• The lagoon will be constructed and lined/sealed with a HDPE liner. All

water collected in the various drainage ditches and pipes will flow to this

lagoon.




• An additional water tank will be constructed at the same time as the

settlement lagoon to provide additional storage capacity if required.

• Settlement ponds will be covered by firm wire mesh (WeldMesh) of small

enough mesh size to prevent access to birds.

Site Drainage Installation

• A surface water drainage system will be installed in the roads, shear keys

and main site as each section of works progresses.

• The drainage system will consist of gullies, underground pipework,

manholes and a number of lined open ditches.

• This system will collect all rainwater by gravity flow to the settlement

lagoon, passing through a bypass separator.

Acoustic Barrier Construction

• The entire tunnelling compound will be surrounded by an acoustic fence.

• Acoustic fence construction will progress in conjunction with shear key

construction.

• This fence will be in place prior to commencement of bulk earthworks.

Bulk Earthworks

• Once the shear keys, settlement lagoon and overground water storage

tank have been installed bulk excavation of the main body of peat will

commence.

• This will be completed by means of excavators and dumptrucks and will

coincide with the replacement of the peat by imported fill.

• In general, an approximate 0.5m depth of peat will be left insitu to form

the peat stone matrix, the surface peat will be stored onsite and the

remainder transported off site.

• The peat will be completely removed where required in settlement critical

locations.

Flexible Pavement Construction

• A flexible bitumen bound surface will be constructed over the majority of

the site (i.e access roads, shear keys etc).

• This flexible pavement will consist of imported stone and bitumen bound

macadam materials to NRA specifications.

• This will provide an impervious surface to reduce run off from the stone

roads and will provide an easily maintained clean surface for tunnelling

works.

Rigid Pavement Construction

• In certain locations on the site the standard flexible pavement will be

replaced by a rigid pavement.




• The rigid pavement will be constructed from reinforced concrete and will

generally form foundations and bunded areas at various locations.

Retaining Wall Construction

• At various locations retaining walls will be installed where a level platform

or a gradual fall is required for tunnelling works.

• These walls will be constructed from precast items where possible for

future recycling. Where precast structures cannot be used, in situ concrete

walls will be constructed.

Stringing Area

• Once tunnelling operations commence the stringing area construction can

begin.

• This will be completed by means of excavators and dumptrucks and will

coincide with the replacement of the peat by a mixture of tunnel arisings

and imported fill.

• In general, an approximate 0.5m depth of peat will be left in situ to form

the peat stone matrix, the surface peat and vegetation layer will be stored

on site, as for the tunnelling compound, and the remainder transported off

site.

• A stone road will be constructed from the stringing area over to access B,

replacing the original bog mat emergency access. This road will be

constructed 10 months after initial site mobilisation.

Reinstatement

• Once all tunnelling, pipelaying, testing and commissioning are complete

the entire compound will be reinstated with a layer of peat which was

previously stored in the peat storage area.

• All construction materials that can be reused (fencing, bogmats, precast

retaining walls, underground pipework, etc.) will be carefully dismantled

and transported off site.

• Other materials such as surplus stone will be returned to local quarries or

used elsewhere in the locality if possible.

• Materials which cannot be immediately reused (i.e. tarmacadam, concrete

etc) will be transported to a recycling facility.

• Any materials which do not fit the above criteria will be removed to a

licenced waste facility.

• In locations where peat was entirely removed during construction (e.g

crane locations) the imported fill will be excavated and a 1m layer of peat

will be installed on top of the mineral soil level and the fill placed back on

top of this peat layer again.

• The top 300mm to 500mm of stone will be excavated and removed off

site.

• Finally, the entire area will be covered with a layer of peat from the peat

storage area with the site being returned to its original levels in

preparation for habitat restoration.




• The surface vegetation layer will then be reinstated under the direction of

the Project Ecologist.

• Once the area is reinstated, the original drainage system will be reinstated

and the perimeter security fence will be removed off site.

• Stock proof fencing will be erected to protect the reinstated areas.

EQUIPMENT LGP Excavators Tracked Excavators

Articulated Dumptrucks Wheeled Excavators

Front Loading Dumpers Tracked Dumpers

Articulated Trucks (road going) Road sweepers

Water Bowsers Tractors

Rollers Vibrating wackers

Concrete pumps Cranes

Loadalls Generators

Lighting towers Pavers

Chip spreaders Tar sprayers

Tack coaters Pitch cart

Thermoplastic lining trucks

Turving bucket (for use during reinstatement)

RESTRICTIONS • Working adjacent to:

� Blacksod Bay/Broadhaven pSPA.

� Glenamoy Bog Complex cSAC.

• Normal construction work will take place between 07:00 and 19:00

weekdays and 07:00 and 16:00 on Saturday. Only essential works will

carried out between the hours of 19:00 and 07:00.

• Noise and vibration limits.

• Lighting constraints.




POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

Noise, Vibration,

Lighting - Disturbance

• Noise and vibration will be minimized through design, and appropriate

selection of plant and equipment.

• Proactive maintenance of plant and machinery.


• A 3m high non-transparent noise barrier will be installed around the

perimeter of the tunnelling compound.


Increased dust levels • Roads/working area will be dampened down, as required to ensure

dust levels due to construction activities are kept to a minimum.

Potential for indirect

impact on habitats and

species in the adjacent

cSAC /pSPA

• Robust measures (see below) will be implemented to prevent

sedimentation and pollution of the adjacent Annex I estuarine and

interidal habitats in Sruwaddacon Bay and species which depend upon

them, including salmon.

Direct impact on

habitats as a result of

construction activities

Habitat reinstatement and vegetation restoration

• During the initial site establishment works, plant material will be

harvested from areas which will be impacted during construction. This

will be removed from the site for propagation and for use during

reinstatement.

• The surface layer of peat will be stored on site. The stripped vegetation

layer will be placed, right way up – roots downwards, on top of the

peat in the peat storage areas for use in reinstatement.

• If required, stored peat will be covered with Geo-jute to stabilise it and

to encourage vegetation growth following storage.

• During re-instatement, the entire area will be re covered with a layer of

peat, and the vegetation from the top of the peat storage areas will be

replaced under direction from the Project Ecologist.

• A phased re-instatement programme will be undertaken over 1 to 5

years.

• Once the reinstated peat has stabilised, peat forming conditions will be

created by means of pool creation and Sphagnum inoculation.

• Native scrub species will be planted in places in the reinstated peat

storage areas.

Construction activities

may affect local wildlife

(otters and badgers)

• Fencing for the tunnelling compound will be fully wildlife proofed to

prevent mammals entering site.

• Acoustic and visual screening on fences will minimise disturbance to

otters on shorelines of the bay.

• During construction, ramps will be provided at any open trenches

accessible to wildlife to provide a means of escape.

• Work activities will be limited to between the hours of 07:00 and 19:00.

• Night caps will be placed over all pipe ends.




POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION


may affect amphibians

• Any frogs (adults, spawn and tadpoles) identified prior to, and during,

construction will be translocated under licence to a suitable location.

• Habitat reinstatement will re-create the former channel and drain

systems so that frogs may use these post construction.

Disturbance to birds in

the adjacent pSPA and

birds on migration

• Acoustic screening barriers will be installed on the temporary

perimeter palisade fencing.

• Solid acoustic fencing will be used within the compound to minimise

noise.

• Lighting will be designed to minimise light leakage into the pSPA (light

intensity no more than 0.3 lux at the shoreline).

• Green (beacon) lighting will be installed on tall structures and uprights

to reduce collision risk.

• Settlement ponds will be covered by firm wire mesh (WeldMesh) of

small enough mesh size to prevent access to birds.

• Robust sediment and pollution control measures to prevent impact on

prey species in the Bay (benthic macrofauna and fish species).


the locality (other than

in the pSPA)

• A walkover survey will be undertaken prior to construction in order to

ensure that no ground nesting birds are present on lands to be

disturbed.

• Vegetation restoration and planting of native scrub species during

reinstatement.

Pollution of

Land/Water/ cSAC and

pSPA habitats & species

due spillage or leaks of

oil/diesel from plant

and equipment


• Refuelling of plant/machinery will only take place in designated areas.


Release of suspended

solids from the works

could have negative

impact on water

quality, cSAC and pSPA

habitats & species

therein including

salmon

• The surface water treatment system will comprise a bypass separator

for removal of hydrocarbons followed by a settlement lagoon for

removal of suspended solids and the installation of a filtration system

for finer particles.

• V-ditches will be installed up slope and down slope of peat storage

areas.

• In drain mitigation will be placed as required to reduce silt impact on

associated waterways.

• Culverts will be placed at locations where access roads must cross

existing drains and ditches.

• Concrete wash system will be installed.

• Wheel wash system will be installed.


• Any concrete poured in situ will be covered to prevent run off during

rainfall as per industry best practice.




POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

Change in local

hydrology/hydro-

geological regimes.

• An approximate 500mm depth of peat will be left in situ to form a peat

stone matrix in all areas except those classified as settlement critical.

• The stone for constructing the stone road will be locally sourced and

carefully selected to ensure that it is appropriate for the local

environment within the peat.

Works may disturb

archaeological remains

• A licensed archaeologist will be on site to monitor all peat excavation

and tunnelling activities.




Construction of Start Shaft and Ramp

Shell Exploration and Production Ireland Ltd. Title: Construction of tunnel start shaft and ramp

Draft Environmental Management Plan Document No: COR-14-OP-SH-0000_SEPIL EMP


SUMMARY

This document defines the construction methodology and sequence of works for the construction of the

starting shaft and ramp in the Aughoose Compound, for the Corrib Onshore PIpeline. In order to facilitate

commencement of the tunnelling works it is necessary to excavate a shaft and ramp into which the Tunnel

Boring Machine (TBM) will be lowered. The TBM will be lowered in sections into the shaft/ramp for

assembly prior to commencement of tunnelling.

PURPOSE The start shaft and ramp will provide the commencement point for tunnelling works

and will serve as the main access corridor between the tunnel and the surface for

transport of material, plant and labour into and out of the tunnel.

LOCATION The start shaft and ramp will be located in the Aughoose Compound at chainage

88.77. The start shaft is approximately 18m long x 9m wide and 12m deep, the

adjoining ramp is approximately 75m long x 6m wide and ranging in depth from 6m to

12m below ground level. The Aughoose Compound is adjacent to the Glenamoy Bog

Complex cSAC (Site Code 000500) and the Blacksod Bay/Broadhaven pSPA (Site Code

004037).

HABITATS /

CONSERVATION

STATUS

The habitat present at the starting shaft is non-annexed eroding blanket bog. The

Aughoose compound is not in any designated conservation site.

TIMESCALE The duration of construction of the start shaft and ramp is approximately six to seven

months. It is anticipated that construction will take place in 2011/2012.

CONSTRUCTION

METHODOLOGY

The construction of the start shaft and ramp is based on the use of a sheet piling

system with the placement of concrete for support in the lower part of the

excavation.

Under this method of construction the sequence of construction would be as follows:

• In the deeper parts of the start shaft/ramp, where it is required to install

sheet piles through bedrock, the bedrock will be pre-drilled in order to

facilitate the installation of the piles.

• Piles will then be installed to the required depth using appropriate drilling

and driving equipment.

• Commence with initial excavation of material from within the footprint of

the sheet piles (to an initial depth of approximately 2m below the original

ground level).

• Install upper level props or anchors as required to brace the sheet piles.

• Continue with excavations down to bedrock level.

• Install anchors at low level as required to brace the sheetpiles.

• Commence with breaking and excavating of bedrock to the required level.

• Place and construct reinforced concrete support in the lower part of the

excavation.

• Construction of the TBM soft eye / sealing body.

Piling Works

• The ground conditions expected to be encountered in the construction of the




shaft/ramp will consist of an upper layer of engineering fill, mineral soil and

overlying bedrock. It is expected that bedrock will be encountered along the

entire length of the start shaft and ramp. As such the rock will be required to be

predrilled prior to the installation of the piles.

• The size and geometry of the piles installed through the bedrock will be varied to

suit the installation process and the requirements of the detailed design. Where

piles are installed into bedrock it is envisaged that the piles will terminate below

the base of the excavation.

• Following the initial installation of the piles, excavation will commence. As these

progress the sheet piles will have to be propped. To do this a series of walers will

be lifted into position inside the excavation and secured in place onto the

sheetpiles once the upper 2m of excavation has been carried out.

• Where upper level anchors are required in the walls then they will be installed

prior to the positioning of the walers and later tensioned following the

installation of the walers. Lower level anchors may also be required depending

upon the outcome of the detailed design.

Excavations

• Upon installation of the sheet piles it will be required to excavate the material

from within the area enclosed by the sheet piles. Excavation will be carried out in

various stages. Initially, the upper 2m of material will be removed using an

excavator(s) after which a series of struts/wailers will be installed to support the

upper level of the sheet piles. The struts will act as props spanning across the

excavation – props will be secured to walers placed on the face of the sheet piles

within the excavation.

• If necessary, a series of anchors will be installed as described above. Excavations

will then re-commence and be progressed down to bedrock.

• Where bedrock level is reached within the excavation it may be necessary to

install additional anchors through the sheet piles in order to ensure the stability

of the sheet pile structure prior to works progressing deeper. These anchors will

be installed using a drill rig working within the excavation.

• Following the installation of the anchors, excavation for the lower section of the

shaft/ramp will recommence. In order to remove the bedrock from the lower

level of the excavation, excavator(s) will be fitted with hydraulic breaker(s) which

will be used to break out the rock. Depending on the integrity of the rock

encountered additional excavation measures may be required (such as pre-

drilling) to facilitate the extraction/removal of rock.

• As and when sufficient volumes of rock have been broken, an excavator(s) will

remove the broken rock from the excavation. A crane may also be utilised to assit

with the removal of rock from within the lower level of the shaft/ramp.

• Groundwater ingress into the excavation will be controlled by pumping from

sumps located in the floor of the excavation. Water from pumps will be




discharged into the settlement lagoon or to an alternative temporary

storage/treatment facility, if necessary.

• Excavated material brought to the surface will generally be loaded into a dump

truck and either reused on site or transported to a temporary stockpile within the

Aughoose compound from where it will be transported off site.

Placement of Concrete

• Concrete will be required to support the piles in the lower part of the excavation

(through the bedrock) and also for the construction of the required slab at the

bottom of the excavation.

• Upon completion of the excavation works to the required level, reinforced

concrete, 0.5 to 1.0 m thick will be constructed in situ at the bottom of the shaft

and ramp. To prevent uplift of the concrete it may be required to install a series

of rock anchors into the bedrock underlying the reinforced concrete slab. These

anchors will be installed using a drill rig working from within the partially

completed ramp/shaft excavation.

• Low strength concrete will be used to form the TBM soft eye / sealing body.

Reinstatement

• Once the onshore pipeline and associated services have been installed in the

tunnel and the tunnel fully grouted, the start shaft and ramp will be backfilled.

The pipeline and associated services will be backfilled with suitable bedding and

surround material.

• The remaining excavation will be backfilled with suitable material compacted in

layers to within 1m of the underside of the original peat depth where a 1m layer

of low permeability reworked peat will be placed. Further backfilling of suitable

compacted material will continue to the underside of the surface reinstatement

layer, which will comprise peat.

• As backfilling progresses upwards, sheet piles left in situ will be cut to a depth of

1m below finished ground level. Anchors used for bracing of the sheet piles will

be distressed and props/walers removed.

• Reinstatement of the peat layer will be in accordance with the method statement

for the Aughoose Compound.

• The surface vegetation layer will then be reinstated under the direction of the

Project Ecologist.

EQUIPMENT Piling rigs Hydraulic breakers

Mobile cranes Dump trucks

Telehandlers/ Lifting and loading

devices

Rotary drilling equipment

Excavators Drilling rigs for anchor installation

Various pumps Miscellaneous small tools




Noise, vibration and lighting. • Noise and vibration will be minimised through design, and

appropriate selection of plant and equipment.

• Proactive maintenance of machinery.


• Acoustic screening & fencing.


Increased dust levels • Roads/working area will be dampened down, as required to ensure

dust levels due to construction activities are kept to a minimum.

Potential for indirect impact

on habitats and species in the

adjacent cSAC /pSPA

• Robust measures (see below) will be implemented to prevent

sedimentation and pollution of the adjacent Annex I estuarine and

intertidal habitats in Sruwaddacon Bay and species which depend

upon them, including salmon.

•

Direct impact on habitats as a

result of construction

activities

• Careful reinstatement of the area will be carried out following the

completion of the tunnelling works.

• Habitat reinstatement and vegetation restoration will be carried out

as set in the Aughoose Compound Method Statement.

Disturbance to birds in the

adjacent pSPA and birds on

migration

• Mitigation measures, as set out for the Aughoose Compound as a

whole, will be implemented

Disturbance to birds in the

locality (other than in the

pSPA)

• A walkover survey will be undertaken prior to construction in order

to ensure that no ground nesting birds are present on lands to be

disturbed.

RESTRICTIONS Working adjacent to:

• Blacksod Bay/Broadhaven pSPA

• Glenamoy Bog Complex cSAC

Noise and vibration limits

Lighting constraints

Normal construction works will be restricted to between the hours of 07:00 and 19:00

weekdays and 07:00 and 16:00 Saturday.

POTENTIAL ENVIRONMENTAL

IMPACT

MITIGATION




Pollution of Land/Water/ cSAC

and pSPA habitats & species


oil/diesel from plant and

equipment.


• Refuelling of plant/machinery will take place in designated areas

only.


Release of suspended solids

from the works could have

negative impact on water

quality, cSAC and pSPA

habitats & species therein

including salmon.

• Groundwater which may ingress into the excavation will be

controlled by setting up temporary sumps in the floor of the

excavation to dewater the excavation. Pumped water will be subject

to sediment control measures.

• A surface water managment will be utilised to ensure removal of

suspended solids prior to discharge to receiving waters at an agreed

location.

• Please refer to the Aughoose Compound Method Statement

Earthworks may disturb


• A licensed archaeologist will be on site to monitor all excavations in

previously undisturbed areas.


Onshore Works – Construction of Tunnel


Tunnelling Operations

Shell Exploration and Production Ireland Ltd. Title: Tunnelling Operations

Draft Environmental Management Plan Document No: COR-14-OP-0000_SEPIL EMP


SUMMARY

This document describes the construction of the 4.9km segment lined tunnel in which the Corrib Onshore

Pipeline between Glenagd and Aughoose will be installed.

PURPOSE A 4.9km segment lined tunnel will be constructed using a Tunnel Boring Machine

(TBM) between Aughoose and Glengad.

LOCATION The segment lined tunnel will be constructed from the starting shaft located at

Aughoose (approx. Chainage 88.77). From there, the pipeline route traverses

(underneath) the Glenamoy Bog Complex cSAC and the Blacksod Bay/Broadhaven

pSPA at Sruwaddacon Bay in a north-westerly direction towards Glengad for

approximately 4.9km, where the reception shaft (Chainage 83.88) will be

constructed in the cSAC. The tunnel will be constructed with a minimum depth of

cover of 5.5m.

TIMESCALE

It is anticipated that the tunnelling process will take approximately 15 months to

complete (at an average of 11m/ day).

The tunnelling construction will be carried out on a 24 hours a day/ 7 days a week

basis.

Other associated works, such as material transport and tunnel arisings disposal will

be executed between the hours of 07:00 and 19:00 weekdays and 07:00 and 16:00

Saturday.

CONSTRUCTION

METHODOLOGY

The scope of works for the construction of the segment lined tunnel can be

generally divided into the following work steps:

• Construction of the 4.9km tunnel including access ramps, starting shaft

and reception shaft;

• Installation and testing of the 20 inch gas pipeline and services in the

tunnel; and

• Grouting of the tunnel and re-instatement of the shafts.

Further details on the construction of the start and reception shafts are provided in

other method statements.

• Prior to the commencement of tunnelling, the Aughoose compound is

constructed and associated utility systems, e.g. an appropriate surface water

management system, are made available. A separate method statement

describes the construction of the Aughoose compound.

• Plant and equipment required for the tunnelling, including the TBM, are then

mobilised to site.

• All TBM assembly and material supply will be managed from the starting shaft

in Aughoose.




Plant and Equipment

The main plant and equipment required for the tunnelling process include:

• Gantry crane;

• Grout mortar Silos

• Slurry treatment plant

• Bentonite tanks and silos

• Freshwater tank

• Water storage tanks

• Filter press

• Power generation units

Following the installation of all the required plant and the set up of the site

compound and function testing the tunnelling process will commence.

Tunnel construction:

• The tunnel will be constructed using a slurry shield tunnelling method which

involves the drilling/boring of the soil face using a TBM and then installing

precast concrete segments as the TBM progresses.

• The cutting wheel at the front of the TBM tunnels into the ground. The TBM is

controlled by the steering cylinders within the TBM which pushes the cutter

head in the desired direction.

• Power switchboards, hydraulic and logistic units are all installed near the TBM

on a number of back-up trailers. These trailers (typically of 8 – 10 m length) are

interconnected and pulled by the TBM through the tunnel.

• Concrete segments are transported to the front of the tunnel on a train that

runs on tracks within the tunnel during construction. These tracks are installed

in parallel to the tunnelling operation on one of the TBM back-up trailers.

• The stacked segments are transported through the tunnel to the tail skin by a

supply system with train cars and cranes. An erector unit located within the

TBM is used to pick up the segments from the train and it installs the segments

into the designated position. Once installed they are bolted to the already

installed ring and segments.

• Concrete segments which are erected inside the back end of the tunnelling

machine (the tail skin) and assembled to form a complete segment ring which

is connected, grouted and when in position acts as the tunnel lining.

• After completion of one segment ring, all jacking cylinders are extended for a

further advance cycle. By using this method of tunnel lining, the already built

concrete tunnel remains stationary and serves as an abutment for the advance

of the TBM. Grout (annulus grouting) is injected into the overcut behind the

installed segment rings, which is created by the cutting wheel during

excavation.




• Slurry lines for spoil transport, air duct for ventilation, pressurised air supply

and power/communication cables are installed inside the tunnel to support

the drilling process.

• Drilling fluid consisting of a suspension of water and bentonite (bentonite

slurry) is used for lubrication and cooling of the cutting head, removal of

cuttings and stabilisation of the cutting face.

• Bentonite slurry suspension will be pumped through the feeding pipe into the

TBM working chamber. It is mixed with the excavated soil / rock and pumped

back through the slurry discharge pipe to the separation plant at Aughoose

Compound. The soil is separated and the recycled bentonite slurry suspension

pumped through the tunnel back into the TBM working chamber.

• The excavated materials from tunnelling (tunnel arisings) is separated from the

drilling fluid/bentonite slurry mixture using a separation plant where shakers

are deployed and stockpiled temporarily within the Aughoose Compound in

designated area.

• The surplus bentonite slurry will be removed and dewatered in a filter press.

After being treated in the filter press the filter cake is dry enough for

transportation to a licensed waste facility.

Mixing of Grout Mortar

• Grout mortar will be used for grouting the annulus of the tunnel (voids behind

the segments). The grout mortar will also be used for filling the tunnel

following the installation of the pipeline and services.

• Mixing of grout will take place in a controlled and contained environment

using automated mixing tanks located in the Aughoose Compound. Grout silos,

located adjacent to the mixing tanks, will be filled with dry cement brought in

by container truck. The cement will be ‘blown’ into the storage silos from the

container truck using a sealed unit and stored there for mixing as required

during the works.

• The mixing operation will involve the grouting mix and water. This is then

pumped in containers which are transferred to the tunnel using the tunnel

railway.

• To prevent ingress of water and grout into the TBM, brush seals between the

tail skin and the erected segments are filled with grease.

Demobilisation and Reinstatement:

• When the TBM reaches the receiving shaft in Glengad, it will be recovered and

the installation of the gas pipeline and services can start. Installation of the

pipeline and services is from Aughoose.




• Demobilisation of the TBM will be carried out at the Glengad site. Tunnelling

equipment, such as separation plant, bentonite treatment plant, grout silos,

etc. at the Aughoose Compound will be demobilised in stages upon completion

of the significant elements of the works.

• Once the onshore pipeline and associated services have been installed in the

tunnel and the tunnel fully grouted, the start shaft and ramp will be backfilled.

Backfilling of the Tunnel & Pipeline Installation:

• The grout mortar will also be used for filling the tunnel following the

installation of the pipeline and services.

• The equipment associated with this backfilling operation will be located at the

Aughoose compound and the backfilling operation will be carried out from one

side only by pumping the backfilling mix through the pre-installed grouting.

EQUIPMENT Tunnel boring machine (TBM) Filter press

TBM back-up system Supply system, feeding pipes / cables

Tunnel segments Control Station

Track and train system Lifting and loading devices

Separation plant Tanks

Bentonite handling unit Gantry crane

Bentonite silos Mortar silos

RESTRICTIONS Tunnel will be constructed underneath:

• Blacksod Bay/Broadhaven pSPA

• Glenamoy Bog Complex cSAC

Noise and vibration limits

Lighting constraints

Non-essential activities may require to be suspended at the Aughoose Compound

on Easter Sundays during periods when Mass is taking place at the nearby

commemorative site.




POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

Release of bentonite to

environment

• The composition of slurry is designed to suit the geotechnical conditions.

• Bentonite pressure and rate of usage will be monitored constantly. In the

event of bentonite release the bentonite operating pressure will be reduced

immediately to reduce bentonite loss.

• Bentonite sensors will be installed in the excavation chamber. The chamber

can be separated from the slurry system.

• The TBM speed will be altered to suit the ground conditions.

• In the unlikely event of a bentonite release the design and operation of the

TBM will limit the volume to 7m3.

• Measures will be implemented at Aughoose and Glengad to prevent any

egress of bentonite into watercourses leading into the cSAC /pSPA. A hard

standing area for bentonite handling plant will be located in the Aughoose

Compound. There is a separate drainage system where the run-off is

collected and pumped into a used bentonite tank. During removal of the

TBM at Glengad, the shaft will be partially flooded. This water will be

contained within the shaft and removed offsite for treatment at an

appropriate licensed water treatment facility. Robust measures will be

taken to ensure there is no bentonite release during the loading, handling

and transport of the TBM in Glengad.

Noise, vibration and

lighting disturbance.

• Noise and vibration will be minimised through design, and appropriate


• Proactive maintenance of machinery.

• Cladding of stationary machinery such as generators and separation plant.

• Acoustic screening & fencing.





POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION


the adjacent pSPA and

birds on migration

• Acoustic screening barriers will be installed on the temporary perimeter

palisade fencing.

• Solid acoustic fencing will be used within the compound to minimise noise.

• Lighting will be designed to minimise light leakage into the pSPA (light

intensity no more than 0.3 lux at the shoreline).

• Green (beacon) lighting will be installed on tall structures and uprights to

reduce collision risk.

• Settlement ponds will be covered by firm wire mesh (WeldMesh) of small

enough mesh size to prevent access to birds.

• Robust sediment and pollution control measures to prevent impact on prey

species in the Bay (benthic macrofauna and fish species).

• See LVI, Glengad Compounds and Access Road MS for details of further

mitigation.

Potential for indirect

impact on habitats and

species in the adjacent

cSAC /pSPA

• Robust measures (see below and Aughoose Compound Construction MS)

will be implemented to prevent sedimentation and pollution of the adjacent

Annex I estuarine and interidal habitats in Sruwaddacon Bay and species

which depend upon them, including salmon.

Pollution of

Land/Water /cSAC and

pSPA habitats & species



and equipment.






could have negative

impact on water quality

• A surface water management system will be utilised to ensure removal of

suspended solids prior to discharge to receiving waters at an agreed

location.




• A licensed archaeologist will be on site to monitor all excavations of the

tunnel start and reception shafts.

• In the event of an archaeological find the archaeologist may have work on

the site stopped, pending a decision as to how best to deal with the

archaeology by the Department of Arts, Heritage and Gaeltacht Affairs

(DAHGA) (previously assigned to the Department of Environment, Heritage

and Local Government (DoEHLG).


Onshore Works – Construction of Tunnel


Bentonite Handling and Monitoring

Shell Exploration and Production Ireland Ltd. Title: Bentonite Handling and Monitoring



SUMMARY

This document describes the handling and monitoring of bentonite during tunnelling for the Corrib

Onshore Pipeline project.

WHAT IS

BENTONITE?

Bentonite is a natural product comprising very fine inert clay which is widely used

in an aqueous suspension in tunnelling construction projects.

Bentonite is considered by the OSPAR Commission* as being a substance that

Poses Little or No Risk to the Environment (PLONOR)

PURPOSE The Corrib Onshore Pipeline will be installed into a 4.9km segment lined tunnel.

4.6km of this tunnel will be constructed beneath Sruwaddacon Bay which

comprises part of the Glenamoy Bog Complex cSAC and the Blacksod

Bay/Broadhaven pSPA.

A tunnel boring machine (TBM) will be used to construct the tunnel by excavating

material in front of the TBM, behind which concrete segments will be installed.

A drilling fluid consisting of a suspension of water and bentonite (bentonite

slurry) is used for lubrication and cooling of the cutting head, removal of cuttings

and stabilisation of the cutting face.

BENTONITE USE • The bentonite slurry will be pumped to the TBM via pipes within the tunnel

where it is introduced at the cutting face. As the soil is excavated by the TBM,

it passes through a crusher at the rear of the cutting head.

• All material is reduced to a maximum size of approximately 40mm and then

hydraulically transported as a bentonite slurry to the surface via the slurry

discharge line.

• The bentonite slurry containing the excavated material is pumped back to the

seperation plant located at the Aughoose Compound.

• Excavated materials from tunnelling (tunnel arisings) will be separated from

the bentonite slurry mixture and stock-piled temporarily on the site in

purpose designated area.

• Recycled slurry will be pumped back to the TBM excavation chamber by

means of feed pumps located at the separation plant and in the tunnel where

the process is repeated.

• Solids will be removed from the excess bentonite slurry in a filter press and

the solid cake (filter press outcome) will be disposed of at licensed waste

facility. Process water from the filter press requiring disposal is tankered

away and disposed off at a licensed water treatment plant.

BENTONIITE

HANDLING

Bentonite handling will occur in the following areas: and the process is outlined in

Figure 1 below :

Bentonite mixing plant

• Bentonite will be delivered as powder to the Aughoose Compound where it




will be stored in silos.

• The supply of dry bentonite powder to the mixing plant is fully automated via

a closed screw conveyor system. Bentonite will be mixed with water in the

bentonite mixing plant prior to being pumped to the fresh bentonite storage

tank. This process will be carried out within a closed system.

Fresh Bentonite Storage Tank

The fresh bentonite storage tank is used to store the drilling fluid before it is used

at the TBM tunnelling process.

Separation Plant

• The purpose of the separation plant is to separate the excavated material

from the transporting medium (bentonite slurry).

• The separation plant is the central facility where the bentonite slurry coming

from the TBM is treated and recycled. It is then fed back to the header tank

(linked to the fresh bentonite storage tank) through the slurry circuit to the

TBM.

Filter Press

• The function of the filter press is to separate the remaining solids from the

used slurry from the separation plant.

• After being treated in the filter press the solids are stored prior to been

disposed off at a licensed waste facility.

• The remaining liquid will be disposed of at licensed wastewater treatment

plant.

* OSPAR commission: Administrator of the Oslo and Paris Conventions for the protection of the marine environment

of the North-East Atlantic




FIGURE 1: TYPICAL BENTONITE SLURRY FLOWCHART




CONTROLS The bentonite slurry system is a controlled operation from the silos to the cutting

face and back through the slurry system to the separation plant.

During Tunnelling

• Bentonite slurry will penetrate the surrounding ground over a short distance

in order to support TBM face during tunnelling. The pressure of the slurry at

the soil face will be controlled by a compressed air cushion inside the TBM,

which allows for rapid changes of the slurry volume in mixed ground

conditions, while automatically maintaining a pre-set face support pressure.

The pressure at the soil face will be continuously measured and monitored by

the TBM operator and alarmed when limit values are met.

• The design and the operation of the TBM will ensure that any break-out

release will be contained to around 7m3

• In the unlikely event of a:

• Bentonite loss beyond the immediate vicinity of the tunnel bore; the

bentonite operating pressure will be reduced.

• Uncontrolled bentonite leakage within the slurry circuit; internal actions

will be initialised immediately to identify and eliminate the cause of the

problem.

• Uncontrolled bentonite breakout on the TBM cutting head; the

bentonite operating pressure will be reduced immediately to reduce

bentonite loss. Immediate actions will be initialised to identify, eliminate

the cause of the problem.

Onsite at Aughoose Compound

• Bentonite handling will be carried out within a closed system and located in a

hard standing area. It will have a separate drainage system from which all

run-offs will be collected and pumped into a used bentonite tank.

• Bentonite, though not considered to be a hazardous material, will be stored

and handled within a contained unit. Surplus bentonite slurry following

completion of tunnelling will be treated and disposed of at an appropriate

licensed water treatment facility.

Onsite at Glengad Reception Shaft Compound

• During removal of the TBM at Glengad, the shaft will be partially flooded. This

water will be contained within the shaft and removed offsite for treatment at

an appropriate licensed water treatment facility.

• Robust measures will be taken to ensure there is no bentonite release during

the loading, handling and transport of the TBM in Glengad.

MONITORING The use and consumption of drilling fluid in the tunnelling process will be

monitored throughout the works by material balance calculations and pressure




control.

• The bentonite slurry level in the cutter head is continuously monitored by

a series of level sensors.

• The volume imbalance or the reduction in pressure and bentonite levels

would alert the operator and mitigation measures as listed below would

quickly be put in place to control any localised breakout.

• The feed and discharge pipes of the TBM are equipped with a flow

indicator and a density measurement system to monitor the most

important parameters of the bentonite suspension and mass balance. All

values will be stored electronically and can be monitored at any time in

the control cabin of the TBM as well as in the site office and the

Separation Plant.

• The separation plant control cabin is also equipped with monitoring

equipment where all the bentonite suspension data is shown.

• In the TBM the face pressure will be monitored by the TBM operator via

pressure sensors located in the excavation chamber. The pressure values

will be electronically stored and can be monitored continuously in the

control cabin of the TBM as well as in the site office and the separation

plant.

EQUIPMENT TBM

Separation Plant

Filter press (secondary slurry process)

Fresh bentonite tank

Used bentonite tank

Slurry pipes

Slurry pumps




POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

Release of bentonite to

environment

• The composition of slurry is designed to suit the geotechnical conditions.

• Bentonite pressure and rate of usage will be monitored constantly.

• Bentonite sensors will be installed in the excavation chamber. The chamber

can be separated from the slurry system;

• The TBM speed will be altered to suit the ground conditions.

• Measures will be implemented to prevent any egress of bentonite into

watercourses leading into the cSAC /pSPA at Sruwaddacon Bay. A hard

standing area for bentonite handling plant will be located in the Aughoose

Compound. There is a separate drainage system where the run-off is

collected and pumped into a used bentonite tank. During removal of the

TBM at Glengad, the shaft will be partially flooded. This water will be

contained within the shaft and removed offsite for treatment at an

appropriate licensed water treatment facility. Robust measures will be

taken to ensure there is no bentonite release during the loading, handling

and transport of the TBM in Glengad.

• In the unlikely event of a bentonite release the design and operation of the

TBM will limit the volume to 7m3.




Construction under Leenamore Inlet

Shell E&P Ireland Ltd. Title: Construction under Leenamore Inlet

Environmental Management Plan Document No: COR-14-OP-SH-0000 SEPIL EMP


SUMMARY

The works involve the construction of the Corrib Onshore Pipeline across the Leenamore inlet and the wet

marshy areas either side.

PURPOSE Outline the general methodology for the construction of the onshore

pipeline through the Leenamore inlet and wet grasssland areas either side

of the river inlet.

LOCATION Leenamore inlet crossing and wet marshy areas either side (pipeline

chainage 89.11 to 89.35.)

The Leenamore inlet lies within the Glenamoy Bog Complex cSAC (Site Code

000500) and the Blacksod Bay/Broadhaven pSPA (Site Code 004037).

HABITATS/CONSERVATION

STATUS

Habitats comprise non-annexed improved wet rushy agricultural grassland

on either side of the inlet.

Intertidal habitats (EU annexed i: Mudflats and sandflats not covered by sea

water at low tide and Upper and Lower Saltmarsh) are non-qualifying

habitats located within the cSAC and pSPA. The approximate area of these

habitats to be disturbed at this location is 2,000 m², which equates to less

than 0.002% of the cSAC’s total land cover.

TIMESCALE/ TIMEFRAME

Approximately 6 weeks (river crossing period is approximately 2 days). It

will be completed during a period of optimum conditions (dry period of low

river flow coinciding with a period of neap tides). Construction will not take

place during the salmon spawning season without prior written agreement

from IFI and DCENR.

TECHNIQUE Temporary working area preparation works

• A 85 metre wide area will be fenced with 3m high fencing.

• A section of this fence will be located on the foreshore.

• The fence will be situated on bogmats or on precast concrete slabs

where ground conditions require.

Crossing Preparation works

• Concrete coated pipes will be prepared prior to construction.

• Cobbles within the river inlet to which epifauna & flora are attached will

be preserved by relocating to a similar position in the intertidal zone on

the shore, away from the works area. These will then be reinstated on

completion of construction works. A survey of the intertidal area will be

carried out on a receding tide to mark tidal lines in advance of

cobble/stone relocation and storage during the works.

• Areas of salt marsh likely to be impacted by the works will be turved by

means of an excavator with a specially designed turving bucket. The

machine used for salt marsh turving will work in the inter-tidal area and

transfer turves to a turve storage area. Machinery will not be allowed to

track across the salt marsh during the separation of upper layers of the

foreshore.

• The salt marsh turves will be stored in the intertidal area in a single

layer, on the foreshore which will be cleared of large stones prior to

placement. This will provide an even surface for storage.

• A geotextile will be used at the seaward edge of the stored turves to

protect against wave action in high winds. The geotextile will be




removed prior to lifting of turves during reinstatement.

• The salt marsh turves will be stored at the western edge of the

Leenamore Inlet, to the north of the pipeline route but within the

temporary working area, as this area is least susceptible to wave action

during prevailing westerly winds.

• The surface layer (approximately 300mm) of the intertidal area will be

carefully lifted and stored to reduce the impact to the organisms

therein. This material will be used for reinstatement.

• The two processes (salt marsh turving and separation of upper layer of

foreshore) will be undertaken at the same time, at low tide, allowing

gradual access across the inlet.

Onshore preparation works

• The top soil in the wet grassland areas on either side of the inlet will be

stripped and stockpiled to one side of the temporary working area and

stored separately from the underlying peat /peaty soil.

River Crossing Preparation

• The Leenamore River crossing will be carried out using an open-cut

trench. A stone road will be constructed using locally sourced, washed

stone (screened to remove fines) within 10 metres either side of the

river crossing.

• A sand bag dam structure will be placed across the river inlet on both

sides of the excavation area. This structure will assist in containing

sediments, mobilised during excavation works, within the working area.

• A flume pipe will be laid on the bed of the river to direct flow through

the temporary working area. The flume pipe will be used to divert river

flow during construction activities and will allow installation of the

onshore pipeline.

• If required by the Inlands Fisheries Ireland (IFI), electrofishing will be

carried out, under permit, prior to instream works. All fish encountered

will be removed and relocated upstream. A strip net will be placed

upstream to prevent fish from entering the area. The stop net will be

removed upon completion of the works.

• A temporary access bridge for construction traffic will be installed for

crossing of the Leenamore Inlet during pipeline installation works.

Pipeline Installation

• The trench will be excavated so that the cover above the pipeline to the

riverbed will be a minimum of 1.6m.

• Excavation will be carried out using two excavators located at opposite

sides of the river inlet. Machinery movement within the inter-tidal area

will be avoided.

• Excavation will be carried out using perforated buckets to allow

separation of solid material from water.

• Excavated material will be loaded into dumpers and transferred to the

Aughoose Compound for storage.

• Once the trench is ready the prefabricated pipelines (one pipeline, one

sleeve) will be transported from the Aughoose compound and placed

into the trench.




Reinstatement of the inlet

• Following the laying of the pipeline and sleeve, the trench will be

backfilled initially with a 150mm sand or pea gravel surround followed

by coarse, silt free material (natural gravel) or, depending on quality, the

excavated material. Impact protection in the form of precast concrete

slabs will be placed over the pipeline and sleeve.

• The upper layer of river bed sediment (300mm), that was stored

separately, will be replaced to reinstate the area where the open trench

existed.

• The geotexile protection will be removed prior to lifting the turves from

the storage area. The salt marsh turves will then be moved back into

place. Temporary staking and horizontal timber boards (planks) will be

used to protect the outer edges of the turves against wave action during

recovery. Biodegradable geogrid may be used on the surface of the

turves if considered necessary.

• The banks of the inlet will be stabilised to prevent bank erosion. Any

excess stone will be removed.

• The temporary access bridge will be removed during reinstatement of

the salt marsh.

• Finally, the large cobbles will be reinstated.

Reinstatement of the fields either side of the inlet

• The wet grassland areas on either side of the inlet will be reinstated by

means of replacing the underlying peat /peaty soil and then spreading

the stockpiled top layer material in readiness for landscaping and

planting.

• All security fencing will removed after reinstatement completion.




EQUIPMENT

Lifting Booms Turving bucket

Bulldozer. Articulated trench rollers

Dump trucks. 6 inch water pumps

Rubber tyred excavators Filtration tank

Tracked Excavators

RESTRICTIONS • The Leenamore inlet is within the Glenamoy Bog Complex cSAC and the

Blacksod Bay / Broadhaven pSPA.

Intertidal habitats are EU Annex I habitats (EU Habitats Directive):

1. Atlantic salt meadows (Salt marsh).

2. Mudflats and sandflats not covered by sea water at low tide.

• Requirement to turve areas of upper and lower salt marsh.

• Tidal conditions in the estuary and fluvial flows from the Leenamore

River.

• Works will be completed during suitable tides and during a period of low

flow in the Leenamore River.

• Construction work will be restricted to take place between 07:00 and

19:00 weekdays and 07:00 and 16:00 on Saturdays.


• Lighting constraints .

• Works will be undertaken only after prior agreement with relevant

statutory bodies, in consultation with the Project ecologist.




POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

Construction Works

negatively impacting

local environment

• Duration of construction will be minimised.

• Mammal gates will be provided at the base of the fencing at 75m intervals to

allow otters and badgers free access across and a means of escape from the

temporary working area.

• Ramps will be provided at intervals along the trench line to allow a means of

escape for wildlife should they enter the trench.

• Weather forecast and tide tables to be observed before commencement of

construction in this area to ensure works are undertaken in suitable

conditions.

• Works will be undertaken in summer time i.e outside the overwintering

period for the pSPA.

• A walkover survey of onshore sections including shorelines will be undetaken

prior to construction in order to ensure that no ground nesting birds are

present on lands to be disturbed.

• Water monitoring will be carried out in line with section 2.5.3 of the

Environmental Monitoring Programme (EMP, Appendix A).



could have negative

impact on estuarine,

intertidal, and

riparian habitats and

species.

• Containment, settlement and /or filtration methods will be used where

necessary and will be put in place prior to commencement of preparation

works.

• Once the river flow is isolated, river bed excavation works can commence.

Operation of machinery within the river inlet and use of machinery in the

immediate vicinity of the inlet will be kept to a minimum to avoid any

unnecessary disturbance.

• Disturbance of bankside soils and inlet sediments will be kept to the

minimum required for the pipe laying process to avoid unnecessary impact

on the river habitat.

• If pumps are utilised, care will be taken to screen pump inflows to protect

fish and to ensure that the watercourse upstream of the barriers is not

pumped dry.

• Splash plates will be placed at the outflow of pumps to ensure that scouring

and suspension of fine sediments does not take place.

• Locally sourced quarry stone will be used adjacent to the inlet

(approximately 10m each side).

• Upon completion of the instream work, the inlet will be restored to its

original configuration and stabilised to prevent bank erosion by means of

timber stakes, timber planks and geotextiles as required.

Pollution of terrestrial

/ aquatic habitats due

spillage or leaks of


and equipment.

• Machinery and plant will be inspected for potential leaks prior to being used

in the crossing works.






POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

Release of sediment

from works could

have negative impact

on estuarine,

intertidal, and

riparian habitats and

species.

• Sediment Control measures will be put in place prior to commencement of

preparation works.

Interference with the

chemical balance

caused by non-

chemically

compatible materials

such as stone.

• Locally sourced and washed quarry stone will be used adjacent to the river

inlet (approximately 10m each side).

Noise, vibration and

lighting Disturbance.


selection of plant and machinery

• Proactive maintenance of plant and machinery will be carried out.


• Mobile lighting will be designed to limit light spillage.


may have a negative

impact on salt

marshes due to the

friable nature of the

substrate and

relatively low

coherence of the

vegetation layer.

• Machinery will not be permitted to move across areas of salt marsh during

the separation of upper layers of foreshore.

• Control measures outlined in the construction technique must be complied

with. Particular attention will be given to protection of salt marsh prior,

during and post construction.

Damage to river

bank.

• Upon completion of the instream work, the river inlet bank will be restored

to its original configuration and stabilised to prevent bank erosion by means

of timber stakes and fencing.

Earthworks may

disturb archaeological

remains.

• A licensed archaeologist will be on site to monitor all ground disturbances.




Onshore pipeline construction in recovering eroded blanket bog

(190m section)

Shell E&P Ireland Ltd. Title: Construction in recovering eroded blanket bog (190m)



SUMMARY

The works involve construction of a pipeline (and associated stone road) in a 190m section of recovering

eroded blanket bog and the reinstatement of same.

PURPOSE Outlines the general methodology for completing the onshore gas pipeline through a

190m section of recovering eroded blanket bog.

LOCATION Aughoose, pipeline chainage 89.35 to 89.54

HABITATS /

CONSERVATIO

N STATUS

Recovering eroded blanket bog which is expected to return to, but has not yet

achieved, EU Annex I habitat quality.

This is not within any designated conservation site.

TIMESCALE/

TIMEFRAME

Approximately 10 weeks to coincide with summer season

TECHNIQUE Supervision and Independent Verification

These works will be supervised by a suitably experienced and qualified geotechnical

engineer or geologist familiar with construction in peat. The role of the supervising

engineer is to ensure that the works have been carried out in accordance with the

specifications and standards as set out below. In this regard, the supervising engineer

will carry out an independent verification of the works (that is installation of reworked

peat layer) similar to a construction quality assurance (CQA) approach.

Specification, Installation, Supervision and Verification will be completed in accordance

with the following reports:

1. Reworked peat & mineral soil permeability research, AGEC, October 2009;

2. Report on Trial Trench and Impedance Layer (Chainage 89.350 to 89.540),

AGEC, May 2011.

Site Preparation

The 40m wide temporary working area will be set up as follows:

• Install 3m high palisade security fencing mounted on bog mats.

• In order to facilitate the construction of a 9m wide stone road the upper vegetation

layer of peat will be removed as turves.

• The turves will measure approximately 2m x 1m x 0.5m and will be laid carefully on

bog mats in single layers within the temporary working area and stored for

reinstatement on completion of the works. The turves will be stored close together

to prevent drying of edges. They will be monitored during storage and irrigated as

required.




Stone Road Construction

• The process of installing the stone road will be a combination of excavation and

displacement of peat with stone. The depth of stone will vary depending on the

depth of the peat.

• This area may need to be sheet piled prior to stone road construction to allow for

safe pipe laying activities.

• Following removal of the turves, peat will be excavated to a nominal depth of 0.5m

from the base of the peat. Imported, single size stone will be pushed into this peat

layer to form a peat stone matrix.

• Suitable peat excavated during stone road construction will be stored within the

temporary working area outside the 190m for future use in backfilling the pipe. The

specification and testing requirements to determine suitability of this peat will

conform with the recommendations outlined in the reports entitled 'Reworked peat

& mineral soil permeability research' (AGEC, October 2009), Report on Trial Trench

and Impedance Layer (Chainage 89.350 to 89.540), (AGEC, May 2011).

• Additional peat for regulating the surface of the stone road prior to reinstatement

of the turves will also be stored outside of the 190m.

• The remainder of the excavation will backfilled with a standard graded stone to a

level approximately 0.8m below the original surface level of the bog.

• An additional bog mat access will be constructed adjacent to the stone road for

pipeline installation activities only.




Pipeline installation

• In this area, the trench excavation will go below the peat stone matrix in order to

get the required cover over the pipeline. This will involve excavation into mineral

soil.

• String out pipeline and other services on bog mat road and prepare for laying.

• Excavate trench and install pipe bedding.

• Excavated material will be placed on the stone road to raise the level of the stone

road to that of the bog mat access, ensuring a level running track for operation of

side booms.

• All mineral soil excavated during trench construction will be transported to a

licensed facility for disposal.

• Install gas and service pipes, and surround services with suitable material (sand or

pea gravel) as per pipeline designer’s specification.

• Roll out a geotextile layer over the level pea gravel. The width of the placed

geotextile filter membrane shall be of sufficient width to cover the trench base, side

walls and to allow a nominal 100mm lap above the interface of the peat and

mineral soil on both sides of the trench.

• Place a 1000mm deep layer of suitable reworked peat over the geotextile as




follows:

o Suitable reworked peat will be placed into the trench using an excavator

bucket so as not to damage the geotextile filter membrane.

o Suitable reworked peat shall not be dropped from a height.

o Suitable reworked peat shall be placed uniformly into the trench to avoid

excessive dragging and to avoid spreading of peat over the geotextile.

o No compaction of the reworked peat layer is required other than light

pressing during placement using the back of an excavator bucket.

o Suitable reworked peat shall contain no large clods or other material

prohibited by the specifications (AGEC, 2009, and AGEC 2011).

o Testing of reworked peat is required; refer to Test Requirements and

Acceptable Limits for Reworked Peat Layer in Pipeline Trench, AGEC 2009,

and AGEC, 2011.

o During placement of reworked peat layer the trench shall be kept free of

water.

• Place 300mm layer of clean stone immediately above reworked peat layer.

• Backfill remainder of trench with trench arisings (that is stone road fill) stored on

stone road.

Reinstatement

It should be noted that reinstatement of this area will run concurrently with

reinstatement of the grassland area east of the Leenamore river crossing and will

proceed as follows:

• Once the pipeline trench has been backfilled, remove the bog mats from beside the

stone road.

• On reinstatement of this area, a regulation 100mm layer of peat will be spread

upon the stone road. The peat used for this process will be original peat excavated

from the area.

• Stored turves will be packed firmly over the regulation layer and any gaps will be

hand-packed with peat scraw as the process is being done.




• Care will be taken to avoid compaction during reinstatement and the turves will be

reinstated to a slightly higher level than the surrounding bog in order to allow for

settlement post construction.

• The reinstated turves are to be replaced carefully, under the supervision of the site

Environmental officer under the direction of the Project Ecologist.

• Bog mats used for turve storage will be removed immediately after turve

reinstatement.

Monitoring, Testing & Reporting

• Groundwater and peat water level monitoring will be completed in accordance with

Section 7.7 of AGEC, 2009, and in accordance with the Environmental Monitoring

Programme (SEPIL, 2011).

• Independent on-site and laboratory testing will be completed on reworked peat

samples as per requirements of AGEC, 2009, and AGEC, 2011. Tests shall include:

o Moisture content (during storage and placement)

o Laboratory hydraulic conductivity (permeability), (during storage

and placement)

o Visual homogeneity

o Geotechnical engineering description (during storage and

placement)

o Peat thickness (during excavation)

• The following reports will be prepared in accordance with Section 7.5 (7) of AGEC,

2009:

o Daily reports.

o Test Report (including field and laboratory testing).

o Validation Report Prior to Commissioning.

• For further details of monitoring, testing and reporting reference should be made

to Environmental Monitoring Programme (SEPIL, 2011) and reports AGEC 2009

and AGEC 2011.




EQUIPMENT Side Booms.

Bulldozer.

Dump trucks.

Rubber tyred excavators.

Tracked Dumpers

Tracked Excavators

Articulated trench rollers.

6 inch water pumps

Turving Bucket

RESTRICTIONS • Working in an area of recovering eroded blanket bog which will be treated as

though it were EU Annex I blanket bog habitat.

• Working in close proximity to, and upslope of, the Glenamoy Bog Complex cSAC

and Blacksod Bay / Broadhaven pSPA, and the Leenamore River.

• No vehicle movements will be permitted outside the fenced working area.

• Normal construction work will be restricted to between 07:00 and 19:00 weekdays

and 07:00 and 16:00 Saturday.




Environmental Management PLan Document No: COR-14-OP-SH-0000 SEPIL EMP


POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

Damage to recovering

eroded blanket bog

• The temporary working area width will be approximately 40m to allow

sufficient spacing for storage of turves.

• No vehicle movements will be permitted outside the fenced working area.

• The stone road will be limited to a width of 9m to minimise impact on peat

land.

• A specially designed excavator bucket will be used to lift and place turves

carefully onto wooden bog mats so that the turves do not break up. These

mats will be located alongside the stone road within the temporary

working area.

• Turves will be stored in a single layer on bog mats, stored close together to

prevent drying of edges, and will be monitored and irrigated as required

until reinstatement.

• Stored turves will then be put back to cover the reinstated peat layer on

top of the stone road. Care will be taken to avoid compaction during

reinstatement.

• There will be minimum delay between construction and reinstatement of

this section and every effort will be made to minimise the duration of

disturbance in this area.

Loss of typical blanket

bog species due to

compaction of roots of

vegetation, surface

damage and water

logging from

compaction

• Reduce vehicle movement to a minimum.

• Temporary working area is fenced to prevent encroachment and damage

to the recovering blanket bog outside the working width.

• Low ground pressure vehicles will be used for traversing peat prior to

construction of the stone road. No tracking outside the working area

during the set out phase.

• Only essential vehicles will be used in this section.

• Bog mat access road will only be in position for duration of pipe stringing

and preparation works, they will be removed as soon as the pipes and

services are backfilled.

Hydrological changes

caused by pipeline

acting as a drain

• Placement of reworked peat impedance layer. Works to be completed in

accordance with the following reports:

1. Reworked peat & mineral soil permeability research, AGEC, October

2009;

2. Report on Trial Trench and Impedance Layer (Chainage 89.350 to

89.540), AGEC, May 2011.

• Peat plugs will be placed at approximately 50m intervals to prevent the

road acting as a preferential drainage channel.

• Raised contoured turve ridges will also be placed at 50m intervals to

deflect surface water runoff.

Interference with the

chemical balance

caused by non-

chemically compatible

materials such as stone

• The stone for constructing the stone road will be locally sourced and

carefully selected to ensure that it is appropriate for the local environment

within the peat.


Environmental Management PLan Document No: COR-14-OP-SH-0000 SEPIL EMP


POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

Pollution of terrestrial

and aquatic habitats



and equipment

• Machinery and plant will be inspected for potential leaks prior to being

used in this area.





could have negative

impact on riparian and

intertidal habitats and

species

• Surface Water Control measures will be put in place prior to

commencement of construction works.

• Silt control barriers will be installed along the boundary fence as required

to control sediment run-off.

Noise, Vibration,

Lighting - Disturbance



• Proactive maintenance of machinery to minimise noise and vibration.


• Acoustic screening & fencing to minimise noise.

• Site and mobile lighting will be designed to to limit light spillage.


may affect wildlife

(otters and badgers)

• Egress points will be placed at intervals along the trench line to allow

wildlife means of escape should they enter the trench.

• Mammal gates will be provided at the base of the fencing at 75m intervals

to allow otters and badgers free access across and a means of escape from

the temporary working area.


the locality

• A walkover survey will be undertaken prior to construction in order to

ensure that no ground nesting birds are present on lands to be disturbed

Damage during and

after reinstatement

works

• Stored turves will be packed firmly over a regulation peat layer on top of

the stone road. Gaps will be hand packed.

• Care will be taken to avoid compaction of turves during reinstatement and

the turves will be reinstated to a slightly higher level than the surrounding

bog in order to allow for settlement post construction.

• A stock-proof fence will be maintained to protect the reinstated section.




activities.


Onshore Works – Aughoose to Bellanaboy


Construction in Forested Area

Shell E&P Ireland Ltd. Title: Construction in Forested Area



SUMMARY

This method statement describes the construction of the Corrib Onshore Pipeline in a stone road through

a forested peatland area. A pipeline trench will be excavated, the pipe installed, trench backfilled and the

area reinstated.

PURPOSE This method statement outlines the general methodology for

construction of the Corrib Onshore Pipeline within a stone road through

a forested peat area.

LOCATION Pipeline Chainage 89.54 to 91.42.

This section of the route runs south east crossing commercially forested

land before changing direction where it crosses a road at Chainage

90.137. There is also a small stream crossing in this area at Chainage

90.15. It changes direction again to run south to south west falling

towards a small valley and stream crossing at 90.72 and rising again

towards the Terminal site.

HABITATS/CONSERVATION

STATUS

Habitats comprise commercial forestry plantation and are not within any

designated conservation area.

TIMESCALE/TIMEFRAME

Approximately 6 months with stream crossings, to occur during a dry

weather period.

TECHNIQUE Site Preparation

• The 40m wide temporary working area will be fenced off with 3m high

palisade fencing mounted on bog mats.

• Any necessary tree felling will be carried out under licence and in

consultation with the Project Ecologist during the winter season.

• Areas of dense vegetation, including conifer plantations, affected by the

development will be monitored by faunal experts during vegetation

clearance.

• Conifer trees will be felled and cut to ground level throughout the

working width, leaving roots intact, except along the route of the

pipeline trench, where trees – including roots – will be completely

removed.

Pipeline Construction

• The pipeline will be constructed using the stone road method. At the

western edge of the section (from chainage 89.54) washed stone will be

used in a 10m buffer zone (to protect the recovering eroded blanket bog

to the west of chainage 89.54)

• Peat will be excavated to approximately 0.5m from the base of the peat

and the excavation backfilled with stone to form a peat stone matrix.

The process of installing the stone road will be a combination of

excavation and displacement of peat with stone. The depth of placed

stone will vary depending on the depth of the peat.

• The top surface of peat including the vegetation will be removed by

excavator and kept separate from peat excavated from lower layers.




This material will be retained within the TWA and used during

reinstatement.

• Stockpiled peat will be stored away from the point of excavation.

• Once the stone road is in place, a trench will be excavated in the stone

road, within which the onshore pipeline and services will be laid (1m

separation between the gas pipe and the services). The trench will then

be backfilled using pipe bedding material and the excavated stone.

Stream Crossing (Chainage 90.15)

• Stream crossing will be completed in dry weather conditions.

• Sufficiently sized flume pipes will be placed within the stream and

overlaid with a geotextile membrane.

• A stone haul road is constructed on top of the flume pipes to allow

construction traffic to cross the stream and from which the pipeline

trench will be excavated.

• A dam will then be formed using impermeable clay and a sufficient

number of pumps will be set up. These will over pump any build-up of

water from the upstream side of the stream into its natural course on

the downstream side.

• The trench will be excavated to the required level, with the trench

widened at each end to allow welders to connect the pipe under the

stream to the main pipeline. Sheet piles will be installed where

necessary and imported sand will be used to bed the pipe if conditions

so require. The trench will be kept dry by means of water pumps set up

at a sump box in the low point of the trench. The water will be pumped

into suitable fitration/settlement equipment prior to discharge into the

existing stream. The pipe section, having been strung / welded will then

be laid. The pipeline’s services and outfall pipe will also be installed at

this stage.

• Backfilling of the trench in compacted layers will take place using the

excavated material where possible. Suitable selected fill will be placed

over the top of the pipeline before placing precast concrete slab across

the full width of the stream. The minimum cover over the pipe will be

1.6m at the stream crossings.

Temporary Compound (approx. Chainage 89.85)

• A temporary construction compound approximately 80m x 50m will be

fenced off by means of 3m high palisade fencing. This compound will be

located to the south of the pipeline.

• Any topsoil will be stripped and stored in a designated location within

the compound.

• This compound will facilitate waste storage and contain office and

welfare facilities and may be used as a temporary storage area.

Road Crossing (Chainage 90.14)




• There is a road crossing, which will be constructed using standard open-

cut techniques.

• Liaison with Mayo County Council regarding existing services will take

place and a road opening licence will be obtained prior to construction.

• Traffic control measures in accordance with Chapter 8 of the Dept. of

Transport Traffic Signs Manual will be put in place prior to excavation

works and a Traffic Management Plan will be in operation during the

works.

• A trench will be excavated across the road and pipe sleeves installed

and the trench backfilled. The sleeves will be installed with a minimum

depth of cover of 1.6m.

• A minimum clearance of 300mm will be maintained between the

onshore pipeline and any existing services.

• Impact protection in the form of pre cast concrete slabs will be placed

over the sleeves where they are located under the road.

• Road surfaces will be returned to a standard equal to or better than that

prior to construction of the pipeline.

• The pipeline and ancillary services will then be pulled through the

sleeves during pipeline installation.

Reinstatement

• Any pre existing land drains will be repaired and recorded on the as-

built survey.

• The reinstatement will take place using suitable Low Ground Pressure

(LGP) plant.

• Any remaining roots, branches, etc will be gathered and removed off-

site for later disposal.

• A regulation peat layer of approximately 0.1m will be placed over the

stone road.

• The top layer of peat with remnant vegetation will then be replaced in

preparation for landscaping and habitat creation.

• Upon completion of instream work, the streams will be restored to their

original configuration and stabilised to prevent bank erosion by means

of geotextiles as required.




EQUIPMENT Tracked Excavators

Rollers

Tracked Dumpers

Articulated Dump truck

Low Ground Pressure (LGP) tracked excavators

Side booms

Marookas

RESTRICTIONS • Area to the north of the L1202 is upslope of the Glenamoy Bog

Complex cSAC and Blacksod / Broadhaven Bay pSPA.

• All watercourse crossings (streams and drains) in the catchment of

designated conservation sites, i.e. cSAC & pSPA to the north.

• Noise and vibration limits

• Lighting constraints

• Normal construction work will be carried out between 07:00 and

19:00

• Restrictions will apply in the event of encountering a badger sett

and otter holts along or in the vicinity of the pipeline route. In this

case the mitigation measures outline in EIS appendix J1, Tables 11a

and 11b will be followed.

Shell E&P Ireland Ltd. Title: Construction in Forested area



POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

Construction Works

negatively impacting

local environment

• Weather forecast to be observed before commencement of stream crossing

Noise , Vibraion,

Lighting Disturbance



• Proactive maintenance of plant and machinery will be carried out.


• Mobile lighting will be designed to limit light spillage.

Construction

activities may have

negative impact on

local wildlife (non-

avian and avian)

• Pre-construction surveys for otters and badgers will be undertaken within 1-3

months prior to construction. The areas to be included are approximately; 50-

100m either side of the centre line of the pipeline for otters, and 30m either

side of the centre line for badgers.

• Areas of dense vegetation will be monitored by faunal experts during

vegetation clearance.

• During construction, ramps will be provided at open trenches to provide a

means of escape for otters and badgers and other wildlife to escape.

• Preconstruction fauna surveys, including for frogs, will be undertaken prior to

construction. Any adult frog, spawn and /or tadpoles present will be

translocated under the licence prior to and, if necessary, during construction.

• Mammal gates will be provided at the base of the fencing at 75m intervals to

allow otters and badgers free access across and a means of escape from the

temporary working area.

• A walkover survey will be undertaken prior to construction in order to ensure

that no ground nesting birded are present on lands to be disturbed.



could have negative

impact on stream

flora and fauna.

Potential for

suspended solids to

enter drainage

network/streams

which drain towards

Sruwaddacon Bay

which could have an

impact on salmonids,

frog breeding sites

and otters.

• Containment, settlement and /or filtration methods will be used where

necessary and will put in place prior to commencement of preparation works.

• Once the stream flow is isolated, stream bed excavation works can commence.

Operation of machinery within the inlet and use of machinery in the

immediate vicinity of any stream will be kept to a minimum to avoid any

unnecessary disturbance.

• Disturbance of bankside soils and instream sediments will be kept to the

minimum required for the pipe laying process to avoid unnecessary impact on

the stream habitat.

• If pumps are utilised, care will be taken to screen pump inflows to protect fish

and to ensure that the watercourse upstream of the barriers is not pumped

dry.

• Splash plates will be placed at the outflow of pumps to ensure that scouring

and suspension of fine sediments does not take place.

• Locally sourced quarry stone will be used. Washed stone will be used adjacent

to streams (approximately 10m each side).

Upon completion of the instream work, the stream will be restored to its

original configuration and stabilised to prevent bank erosion by means of

geotextiles as required.

Shell E&P Ireland Ltd. Title: Construction in Forested area



POTENTIAL

ENVIRONMENTAL

IMPACT

MITIGATION

The loss of habitat as

a result of tree felling

and clearing of dense

vegetation has the

potential to have

negative impact on

fauna.

• Any required tree felling will be carried out under licence and outside the bird

nesting season. In the unlikely event that any tree felling is required at any

time during the bird nesting season, such trees to be inspected by suitably

qualified ecologist in advance.

• The edges of the temporary working area will be replanted with the

appropriate tree and shrub species during reinstatement. The top surface of

peat including the vegetation will be removed by excavator and stored

separately from peat excavated from lower layers. This material will be

retained and used as a top layer during reinstatement.

Pollution of

terrestrial / aquatic

habitat / species due

to spillage or leaks of


and equipment.

• Machinery and plant will be inspected for potential leaks prior to being

transported to site.


• Machinery not permitted in stream.


Change in local

hydrology/hydro-

geological regimes.

• As the stone road is constructed, peat plugs will be placed at approximately

50m intervals as required to prevent the road acting as a preferential drainage

channel.

• The stone for constructing the stone road will be locally sourced and carefully

selected to ensure that it is appropriate for the local environment within the

peat. Where possible, tunnel arisings will also be used in combination with

quarry stone for the construction of the stone road.

Earthworks may

disturb

archaeological

remains.


activities.


Onshore Works – Onshore Pipeline Termination Point


Terminal Tie‐in and Surface Water Management within the Carrowmore Lake Catchment Area.

Shell E & P Ireland Ltd. Title: Terminal tie‐in & Surface Water ManagementWithin Carrowmore Lake Catchment

Draft Environmental Management Plan Document No: COR‐14‐OP‐SH‐0000 SEPIL EMPMethod Statement Revision: 01 Page 1 of 5

SUMMARY The works outlined here cover the excavation and installation of the onshore pipeline within the Terminal and all associated diversion of services, surface water management, concrete works, gas pipeline and ancillary services installation as well as painting, testing and reinstatement works. PURPOSE This methodology describes the works associated with tie in of the onshore

pipeline into the Bellanaboy Gas Terminal and the associated diversion of surface water into the Leenamore Catchment.

LOCATION North Western corner of the Terminal. Pipeline chainage 91.42 to 91.72.

TIMESCALE

Approximately 6 Months

TECHNIQUE Site Preparation

A number of existing services within the Terminal will have to be diverted to facilitate pipeline installation including; surface water drainage, groundwater drainage, security fence and associated lighting, road drainage system and road lighting. The sequence is as follows:

• At the tie‐in location, remove gabion baskets, strip topsoil, demolish concrete channel at the bottom of the embankment and strip off surface gravel and weed blanket.

• Excavate existing buried cables and divert south of the pig receiver (point where onshore pipeline ties into terminal structure).

• Insert water stoppers in both the surface water and ground water systems and set up over‐pumping system south of the pig receiver.

• Remove light poles and associated cable junction boxes. • Fence off a temporary working area inside the Terminal to facilitate

pipeline activities. • Dismantle both existing security fences inside the temporary working

area. • Saw cut bituminous road layers, excavate and remove to a recycling

facility. • Demolish concrete open channels and remove to a licensed recycling

facility.

Pipeline Installation Pipeline installation within the Terminal consists of standard welding and pipe trenching procedures used elsewhere on the onshore pipeline in addition to anchor block construction, valve pit construction and overground pipe work painting. The sequence is as follows:

• Excavate pipeline trench from pig receiver to the anchor block location. • Excavate anchor block location and prepare surface for steel fixing by

placing blinding layer of concrete. This will also control surface water within the anchor block excavation.

• Install steel reinforcement, erect temporary timber shuttering and pour concrete base.

• Remove timber shuttering and backfill foundation base up to underside of the pipeline.

• While the anchor block is being constructed the existing surface water and groundwater drainage pipes will be removed from the pipeline route.

• The pipeline and associated ancillary services will be strung out and



welded/jointed and prepared for laying. • The remainder of the pipeline trench will then be excavated and prepared.• The pipeline and ancillaries will then be laid, inspected and backfilled with

suitable material. • The remainder of the trench will be backfilled with the original excavated

material. • The surface water and ground water pipes will be re‐laid during the

pipeline backfilling. These pipelines will be retested prior to allowing them return to normal operation.

• Once the pipeline has been backfilled, the pipeline section situated over ground will be sand blasted and painted for corrosion protection. This may require the erection of a weather proof shelter.

Surface Water Management Surface water from pipeline construction works that lie within the Carrowmore Lake catchment (ch 91.42 to 91.72) will be collected, attenuated and taken through a settlement tank or treatment/filtration unit before being discharged into the Leenamore River catchment (north of ch 91.42). The anchor block and pipeline excavations will be dewatered by pumping surface water to a drain running parallel to the existing stone road. This drain will convey surface water to a settlement tank/treatment unit located upstream of the discharge point into the Leenamore River.

It should be noted that water collected in the Terminal drainage systems will be kept separate from any water collecting in the pipeline excavations..

Reinstatement

Pipeline reinstatement has two distinct operations; reinstating the Terminal inside the permanent security fencing (ch. 91.67‐91.72), and reinstatement of the onshore pipeline temporary working area (ch. 91.42 to 91.67). It should be noted that reinstatement of ch 91.67 to 91.42 is seasonal and will be incorporated during the landscaping/reinstatement of the entire Terminal temporary facilities. Chainage 91.67 ‐91.72 will be reinstated as follows:

• Construct concrete open channels, reinstate gravel area between road and pig receiver and reinstall bituminous road layers.

• Reinstall inner security fences including reinstatement of weed control blanket and gravel between the fences.

• Reinstate light poles and previously diverted underground cables. • Reinstate gravel inside the Terminal and remove temporary fencing. • Reconstruct drainage channel at bottom of embankment batter. • Reinstate topsoil on batter and seed as required. • Reinstall gabion baskets.



EQUIPMENT Minidigger Roller

Front Tipping Dumpers Vibrating compactor (whackers)

Articulated Dump trucks Tracked Excavator (14t‐46 ton)

Road saw Concrete pump

Consaw Concrete poker

Wheeled Excavator Cranes (50‐100ton)

Sand blaster Paint Sprayer

Side booms Welding units

RESTRICTIONS • Surface water from pipeline construction works that lie within the Carrowmore Lake catchment (ch 91.42 to 91.72) shall be collected, attenuated and taken through settlement/treatment units before being discharged into the Leenamore River Catchment (north of ch 91.42).

• Normal construction work is restricted to between 07:00 and 19:00 weekdays

and 07:00 and 16:00 Saturday.



Shell E & P Ireland Ltd. Title: Terminal tie‐in & Surface Water Management Within Carrowmore Lake Catchment



MITIGATION

Noise & Light Disturbance.

• Noise and vibration will be minimised through design, and appropriate selection of plant and machinery.

• Proactive maintenance of plant and equipment. • Noise will be reduced by Cladding of stationary machinery such as

generators. • Acoustic screening and fencing to minimise noise. • Mobile and site lighting will be designed to limit light spillage.


• Sand blasting of pipe work will be carried out under a weather proof shelter. Construction activities may affect local otters and badgers.

• A pre‐construction survey for otters and badgers will be undertaken within 1‐3 months prior to construction. The areas to be included are approximately; 50‐100m either side of the centre line of the pipeline for otters, and 30m either side of the centre line for badgers.

• Areas of dense vegetation affected by the development which could not be thoroughly searched will require monitoring by appropriate experts during vegetation clearance.

• Excavations will allow otters and badgers a means of escape if they get into the excavation. This will be achieved by placing access/egress planks and/or soil ramps at necessary locations.

• Work activities will be limited to between the hours of 07:00 and 19:00 weekdays and 07:00 and 16:00 Saturday.

• Caps will be placed over all pipe ends at night. • Gaps will be left at the base of the fencing at 75m intervals to allow otters

and badgers free access and a means of escape across the temporary working area.

Construction activities may affect amphibians

• Any frogs identified will be translocated under license to a suitable location. • Habitat reinstatement will re‐create the former channel and drain systems

so that frogs may use these post construction. Construction activities may affect nesting birds

• Vegetation clearance will be undertaken outside the breeding bird season i.e. March to August, where feasible.

• Re‐vegetation and planting of native scrub species will be completed during reinstatement.

Pollution of terrestrial and aquatic habitats due spillage or leaks of oil/diesel from plant and equipment.

• Machinery and plant will be inspected prior to mobilisation to site. • Refuelling of plant/machinery will only take place in designated areas. • Spill kits will be available on site.

Shell E & P Ireland Ltd. Title: Terminal tie‐in & Surface Water Management Within Carrowmore Lake Catchment



MITIGATION

Release of pipeline discharge waters to the Carrowmore Lake Catchment could have negative impact on drinking water quality.

• All surface water from construction activities within the Carrowmore Lake Catchment shall be collected, attenuated & treated prior to discharge into the Leenamore River Catchment.

• In drain mitigation will be placed as required to reduce silt impact on associated waterways.

Works may disturb archaeological remains.

• A licensed archaeologist will be on site to monitor all excavations.

Documents

Appendix L Method Statements.pdf