environmental statement · intermediate pig-trap near three cocks, powys this pig-trap installation...

Felindre to TirleyNatural Gas PipelineEnvironmental Statement

Non-technical summaryAugust 2006Designed and produced by M&M Communications Consultants Ltd www.mmcomms.co.uk for RSK ENSR Environment Ltd.

For further information:Copies of the Environmental Statement can be viewedat relevant Local Authority planning offices and otherlocations, please call the freephone number below fordetails.

National Grid freephone number: 0800 731 0561

Additional free copies of this non-technical summary,copies of the Environmental Statement on DVD, andadditional paper copies of the EnvironmentalStatement can be obtained by writing to Mr Des Gellyat the address below. A nominal charge of £15 each ischarged for DVD copies, and £100 each is charged forpaper copies, as a contribution towards the materialcosts. Cheques should be enclosed for DVD and papercopies made payable to ‘National Grid Gas plc’.

Comments on the Environmental Statement for theFelindre to Tirley natural gas pipeline should bereturned to:

Mr G. MohammedDepartment of Trade and IndustryV21211 Victoria StreetLondonSW1H 0ET

It would be helpful if comments could be copied to:

Mr Des GellyNational Grid Project Managerc/o RSK ENSR Environmental Limited18 Frogmore RoadHemel HempsteadHertfordshireHP3 9RT

Non-technical summary

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National Grid Felindre to Tirley pipeline

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Introduction

The challenge – the increasing demand for gas infrastructure

National Grid owns and operates the gas transmissionpipeline system in the UK. This pipeline system isconstantly being enlarged to meet increasing demandand accommodate new sources of supply. As part ofthis process, National Grid is planning andconstructing a number of new gas pipelines andassociated installations from Milford Haven inPembrokeshire to Tirley in Gloucestershire andbeyond. The pipelines will transfer natural gas fromtwo new gas terminals at Milford Haven to bothSouth Wales and the rest of the UK.

The UK Government has already consented toconstruction of the first pipeline, which runs fromMilford Haven to a point to the north-east ofSwansea, and work on this 1220mm diameter 120kmlong pipeline began in spring 2006. Consent is nowbeing sought for the construction of the secondpipeline, from the north-east of Swansea to a pointnear Tirley in Gloucestershire. This second pipeline,

called the Felindre to Tirley pipeline, is due to beconstructed in 2007 and will be 1220mm diameterand 196km long. Both pipelines are required to beavailable to transport gas by the end of 2007 whenthe new terminals at Milford Haven becomeoperational.

As part of the process of seeking consent toconstruct this second pipeline, National Grid isrequired to submit an application to the Secretary ofState for Trade and Industry under the Public GasTransporter Pipe-line Works (Environmental ImpactAssessment) Regulations 1999. The applicationincludes an Environmental Statement, whichexplains how National Grid has assessed the effectsof the pipeline on the environment and how thesewill be minimised both during and afterconstruction has been completed. This non-technicalsummary is a précis of that document.

Why do we need new pipelines?Natural gas consumption in the UK is increasingand, at the same time, natural gas production fromthe North Sea has reached a plateau. Governmentanalysis has shown that the UK will becomeincreasingly dependent upon imported natural gasand the Government’s Energy Review, published inJuly 2006, notes the importance of new gasimportation projects in meeting UK energyrequirements.

Consequently, a number of gas importation projectsare being developed around the UK coast, includingtwo new gas terminals at Milford Haven. TheMilford Haven terminals will have the capacity tosupply up to 20% of UK gas demand.

National Grid is licensed by the Government totransport gas within the UK via its pipeline network.The gas is not owned by National Grid, but thepipeline network provides the means to move itaround the country to where it is needed.

As a licensed gas transporter, National Grid has alegal duty under the Gas Act 1986 (as amended), to‘develop and maintain an efficient, co-ordinated,safe and economical gas transportation system’. Assuch, National Grid is legally obliged to respond torequests for new pipeline connections to its pipelinesystem and has received such a request from theowners of the two new terminals near MilfordHaven. National Grid is also required to reinforcethe pipeline system where necessary to meet itslegal duty.

Why is a new pipeline beingconstructed?To help meet the UK’s future energy needs, twonew gas terminals are being built at Herbrandstonand Waterston near Milford Haven inPembrokeshire. The gas will be transported in liquidform, (Liquefied Natural Gas or LNG), by ship to theUK and will then be vaporised back into natural gasat the two terminals before entering the gaspipeline system. This technology is not new to theUK and was first used in the 1960’s when naturalgas was imported in liquid form by ship fromAlgeria to Canvey in Essex and, after re-gasification, transported by pipeline to themidlands and north of England.

The existing gas transmission pipeline system fromEngland into South Wales terminates to the

north-east of Swansea and is too small toaccommodate the large volume of gas that needs tobe transported from the two new gas terminals.Consequently, in line with its legal obligations,National Grid is required to build two new pipelines:a ‘connecting’ pipeline from Milford Haven to theexisting gas transmission system to the north-east ofSwansea and a ‘reinforcement’ pipeline from north-east of Swansea to a point near Tirley inGloucestershire. These two pipelines will be ofstrategic importance to the UK economy as they willsecure future gas supplies for both industrial anddomestic consumers.

The connecting pipeline from Milford Haven iscurrently under construction and consent from theSecretary of State for Trade and Industry is beingsought for the second (Felindre to Tirley)reinforcement pipeline.

The National Gas Transmission Systemin Great Britain. This picture also showsthe location of the two new LiquefiedNatural Gas terminals at Milford Haven and the pipelines associated with theMilford Haven Gas Connection Projects.

The solution – delivering a new pipeline


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Project descriptionWhat type of pipeline?The Felindre to Tirley pipeline will be constructed withhigh grade welded steel and will be buried at least1.2m (4ft) below the reinstated ground surface.National Grid selected the option of a buried crosscountry pipeline as it provides the safest, most secureand practical method of transporting gas, withminimum, medium or long-term physical orenvironmental impacts. National Grid does not favourabove-ground cross-country pipelines because of theirvisual impact, need for frequent maintenance and thefact that they sterilise the land, preventing its use foragriculture or other purposes. A marine or sub-sea

pipeline solution was also considered, but this wouldhave involved a greater overall length of newpipeline, both on-shore and off-shore, significantenvironmental effects, substantially higher risks andhigher cost.

LegislationWho gives permission for the pipeline?National Grid is required to make an application toconstruct the pipeline to the Secretary of State forTrade & Industry under the Public Gas TransporterPipe-line Works (Environmental Impact Assessment)Regulations 1999. This application is supported by theEnvironmental Statement summarised in thisdocument.

Milford Haven Gas Connection ProjectsIn addition to the Milford Haven connectingpipeline and the Felindre to Tirley reinforcementpipeline, a number of other projects are required tomeet the gas transmission capacity requirementsarising from the two new terminals. The scheme isshown in the diagram entitled ‘The Milford HavenGas Connection Projects’. These other projects willbe designed and constructed under separateconsent and planning applications.

Is there a ‘Do Nothing’option?To ‘Do Nothing’ would restrict gas output from thenew gas terminals and place National Grid in breachof its licence as a gas transporter. Both theconnecting pipeline from Milford Haven, which isalready under construction, and the Felindre toTirley reinforcement pipeline are essentialrequirements in order to comply with theseobligations.

The Milford Haven Gas Connection Projects. This diagram shows the projects necessary to extend and reinforce the NationalGas Transmission System to cope with the volume of gas to be imported via the new Liquefied Natural Gas (LNG) terminals at Milford Haven. The new terminals will have the capacity to supply up to 20% of current UK gas demand.

Compressor station and PIG-trap installationat Felindre, north of SwanseaA 30 megawatt (MW) compressor station and PIG-trapare proposed on a site near Felindre. The compressorstation is needed to compress the gas and so maintainthe gas pressure within the Felindre to Tirley pipeline,thus maintaining full flow capacity. It will containelectric and gas powered compressor units andassociated plant and buildings. PIG-traps are facilitiesat each end of a pipeline, and at strategic intermediatepoints along a pipeline’s length, where pipelineinternal gauge devices (PIGs), which clean and allowinspection of the pipeline, are launched and received.Both the compressor station and the PIG-trap will bewithin a fenced area of approximately 5 hectares (ha),with a 4ha operational area.

Intermediate block valve site south ofLlanwrda, CarmarthenshireBlock valves are comparatively small installationscomprising a fenced area of approximately 0.3ha. Theequipment consists of a number of buried valves thatenable sections of the pipeline to be isolated formaintenance purposes.

Intermediate PIG-trap near Three Cocks,PowysThis PIG-trap installation will comprise a fenced area ofapproximately 0.5ha. and contain two PIG-traps; onefor the receipt of gauges from the start of the pipelineat Felindre and a second to send gauges on to the endof the pipeline near Tirley.

Pressure reduction installation atTreaddow, adjacent to the existingPeterstow compressor station,HerefordshireA pressure reduction installation is necessary to enablea connection to be made between the new pipelinefrom Felindre and the existing gas pipeline system atthe existing Peterstow Compressor Station. The totalsite area will be approximately 2ha, of whichapproximately half will contain equipment. It will belocated in a separate fenced area immediately adjacentto the existing compressor station. Because the twopipelines operate at different pressures, the site willcomprise all the equipment necessary to deal with thissituation including pressure reduction valves, a boilerhouse to maintain the gas temperature and gas filtersand meters.

Pressure reduction installation and PIG-trap at Corse, in the vicinity of the existingTirley installation, GloucestershireAs with the pressure reduction installation atTreaddow, a connection to the existing gas pipelinenetwork is required at the end of the new pipeline inthe Tirley area. In addition to the equipment necessaryto cope with the difference in pressures between thetwo systems, this installation will contain two PIG-trapsto receive monitoring gauges from the Three CocksPIG-trap installation and to send monitoring gaugesinto the existing gas pipeline system. The installationwill comprise a fenced area of approximately 2ha, ofwhich approximately one third will contain equipment.

All of these installations are subject to their ownenvironmental assessment and planning applicationand will be landscaped to minimise visual impact.

Above Ground Installations associated with the Felindre to Tirley pipeline

New compressor station

Existing Above Ground InstallationsProposed Above Ground InstallationsTerminal

Existing compressor station site modifications

Existing compressor station

Peterstow

MilfordHaven

Felindre Derwen Fawr

AberdulaisDyffryn Clydach

PIG Trap TreaddowCorse

South Wales Reinforcement Strategy

TirleyWormington

Churchover

Honeybourne

Proposed pipeline (75barg)


Pipeline under construction(94barg)

Existing pipeline (75barg) Existing pipeline (70barg)

KeyNew compressor station

Existing Above Ground InstallationsProposed Above Ground InstallationsTerminal

Existing compressor station site modifications

Existing compressor station

Peterstow

MilfordHaven

Felindre Derwen Fawr

AberdulaisDyffryn Clydach

PIG Trap TreaddowCorse

South Wales Reinforcement Strategy

TirleyWormington

Churchover

Honeybourne



Pipeline under construction(94barg)

Existing pipeline (75barg) Existing pipeline (70barg)

Key


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Is planning permission required?Licensed gas transporters, such as National Grid, are not required to obtain permission from the local planning authority for the construction of underground pipelines. However, planningpermission under The Town and Country Planning Act1990 is required for any associated installations(usually referred to as Above Ground Installations orAGIs). Planning applications for the AGIs associatedwith the Felindre to Tirley pipeline are in the processof being submitted and further details can beobtained from National Grid (freephone 0800 7310561).

Is an Environmental ImpactAssessment required?As the pipeline will be over 40km in length and willhave a diameter of over 800mm, it falls under Part 1of Schedule 3 of the Public Gas Transporter Pipe-lineWorks (Environmental Impact Assessment)Regulations 1999, which states that anEnvironmental Impact Assessment is required.

Environmental ImpactAssessmentWhat is an Environmental ImpactAssessment?An Environmental Impact Assessment identifiespotential environmental effects caused by theconstruction and operation of the pipeline in orderthat these can be minimised. It comprises a series ofstudies, surveys and consultations that enables thepipeline to be routed to minimise its effects andidentifies measures to ensure successfulreinstatement after construction.

The results of this assessment are summarised in theEnvironmental Statement.

Who is consulted?As part of the process of preparing theEnvironmental Statement, National Grid has carriedout a series of consultations with numerous keybodies including the Local Authorities, the BreconBeacons National Park Authority, the CountrysideCouncil for Wales, English Nature, Cadw (the WelshAssembly Government’s historic environmentdivision), English Heritage, the Environment Agency(England and Wales), the Welsh AssemblyGovernment, the Department for Trade andIndustry, affected landowners and many localcountryside, farming and conservation groups.

How is the best route selected?Several Route Corridor Investigation Studies (RCISs)were carried out to identify, investigate and assesspotential route corridors for the pipeline. Thesewere followed by an extensive series of detailedenvironmental surveys and, in conjunction withlandowner consultation and engineering studies,enabled a preferred route to be selected. Carefulselection of a route is of prime importance inminimising adverse environmental effects.

Several stages were involved in selecting thepreferred route:

1. Identify an Area of Search based on the startand end points of the pipeline;

2. Identify potential route corridors (nominally1km wide, within which the pipeline is laterrouted) using desk-based information;

3. Select a preferred route corridor;

4. Identify a preliminary pipeline route within theroute corridor on the basis of site visits andinitial assessments of available ecological andother information; and

5. Identify the final route during theEnvironmental Impact Assessment of theproject using results from a wide range ofdetailed surveys and studies.

What are the route constraints?The major environmental and engineeringconstraints that have been considered whenrouteing the pipeline have been:

• Populated areas – routeing the pipeline awayfrom areas of population;

• Engineering issues (roads, railways, rivers,cables, other pipelines);

• Construction issues (avoiding steep slopes anddifficult ground conditions);

• The safety of construction personnel;

• Landscape and topography – minimisation ofeffects on the Brecon Beacons National Park,the Wye Valley ‘Area of Outstanding NaturalBeauty’ and other important landscapefeatures and designations including RegisteredHistoric Parks and Gardens;

• Archaeology – in particular avoidance ofimportant sites;

• Nature conservation – in particular avoidanceof rare species which are both nationally andlocally important, ancient woodland andupland areas that are difficult to restore suchas heathland and bog; and

• Mineral extraction and known landfills(avoidance, as far as possible of previousmining areas and suspected contaminatedground).

The results of an extensive range of surveys havebeen used to refine the pipeline route during theEnvironmental Impact Assessment process in orderto minimise the pipeline’s effect on theenvironment. These surveys include ecology,hydrology, geology, soils, archaeology andlandscape and have resulted in the avoidance ofapproximately 45 woodlands, 12 unimproved/semi-improved grassland areas and 2 bog areas. Where ithas been not been possible to avoid notable areas,specialist engineering techniques have beenintroduced to minimise the pipeline’s effect.

The pipeline routeWhere will the pipeline beconstructed?The pipeline starts near Felindre, a village to thenorth of Swansea and the M4. The pipeline runsnorth, turns briefly westwards, then continues

north, passing to the east of Pontarddulais, crossingover the upland common at Cefn Drum, and passingto the west of Ammanford. It then continuesnorthwards passing Llandeilo to the west, where thepipeline swings in an arc around the National Trust-owned Dynevor Park estate, crossing the Afon Tywi(River Towy). The route then turns north-eastwardsrunning up the Afon Tywi valley to the west ofLlangadog before turning east to climb onto theupland common at Mynydd Myddfai and MynyddBach-Trecastell, south-east of Llandovery. Thepipeline continues east, passing just to the south ofSennybridge, crossing the Afon Wysg (River Usk) andpassing to the north of Brecon. The route then turnsnorth, then east, passing south of Llyswen and thennorth-east following the Afon Gwy (River Wye)before swinging around Hay-on-Wye to the south.The pipeline then turns south-eastwards, runningpast Dorstone and down the Golden Valley pastPeterchurch and Vowchurch to Kingstone. Thepipeline route then turns east to enter the WyeValley, crossing the River Wye to the north of Ross-on-Wye, and continuing east, south of Dymock andStaunton, to reach Tirley.

Part of one of the maps prepared to illustrate the environmental designations and issues along the pipeline route.Information on these designations and constraints is used to help route the pipeline, along with survey informationgathered on site.


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ConstructionWhen will the pipeline beconstructed?Construction is planned to start in spring 2007, withcompletion scheduled for autumn 2007. However,some preparatory works will, subject to thenecessary consents, start before this date.Construction of the pipeline will be undertaken bytwo specialist pipeline construction companies.These companies will use a number of teams toconstruct the pipeline at separate geographicalsections.

Who will build the pipeline?National Grid will project manage the pipelineconstruction in its entirety, with the constructionitself being undertaken by the two specialistpipeline construction companies. The sectionbetween Felindre and Brecon has been awarded tothe joint venture company of Nacap Land andMarine and the section from Brecon to Tirley hasbeen awarded to Murphy Pipelines Limited. Bothcompanies have designed and constructed major gaspipelines in the UK over many years and have aproven track record.

What are the construction methods?The general method of pipeline construction isoutlined below:

Preparation of the working width

Growing crops and sections of hedge are removed,and stock or demarcation fencing erected to containthe working area. Bridges or conduits are installed atmost watercourse crossings so that plant andmachinery can cross. The topsoil is then removedfrom the working width and stored to one side ofthe fenced area. Existing field drainage systems areintercepted and new drains installed to maintainexisting field drainage systems and minimise theneed to dispose of water during construction.

The working width is nominally 44 metres wide butwider areas are required adjacent to crossings orwhere the terrain is particularly challenging. Thewidth of vegetation removed at hedgelines,woodlands and along river banks is minimised bycareful route planning. The actual width removed isspecific to each crossing, but is generally between 15metres and 25 metres.

Pipeline stringing and weldingThe pipes, which are typically 12 metres or 18metres long are transported onto the workingwidth, offloaded and welded together on thesurface to form long ‘strings’.

Trench excavation and pipeinstallationA trench is then excavated, the pipe lifted andlaid into it, surrounded by soft material toprotect the pipe coating from damage (this isusually material excavated from the trench thathas been passed through a grader and sorter toremove stones) and backfilled.

ReinstatementLand drains are installed to reinstate pre-existing land drainage patterns. The workingwidth is then cleared, the subsoil ripped torelieve compaction and the topsoil re-laid andcultivated. Temporary bridges at rivers areremoved, hedgerow sections and woodlandbelts replanted and drystone walls andpermanent fences rebuilt. Temporary fencingremains in place until grazing land hasrecovered sufficiently to withstand grazingpressures.

Road, rail and river crossingsThe crossings of larger or ecologically valuablerivers, busy roads and railways may beconstructed by tunnelling to avoid directdisturbance (known as non open-cut methods).For further information on watercourses, seethe section ‘What mitigation measures will beadopted? – Watercourses’.

Pipelineconstruction

method

Trench excavation and pipeline lowering.

General view of the pipeline working area (the ‘working width’).

Preparation of the working width.

Pipeline stringing and welding.

The route of the Felindre to Tirley pipeline.

River crossing by microtunnelling – one of the nonopen-cut techniques available for pipeline constructionunder roads, rivers and railway lines.

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CommissioningThe pipe is cleaned and checked internally and thenpressure tested using water (hydrostatic testing).The pipeline is then dried before being filled withnatural gas.

How is construction managed tominimise environmental effects?National Grid and its contractors’ constructionprocedures are based on established good practice,the latest industry guidance and a number of Britishand International Standards.

Detailed construction and reinstatement proceduresare prepared taking into account possible effects ofthe project on the surrounding environment, roads,archaeological remains, agriculture and localcommunities, as well as considering potential healthand safety issues.

The project management teams will comprise:

• Designated engineers, who are responsible forall health, safety and environmental issues onsite, including safety evaluations and riskassessments;

• Liaison officers, who will maintaincommunication with local communities,farmers and other groups during construction;

• Environmentalists, who ensure that themeasures outlined in the EnvironmentalStatement and Environmental ManagementPlan are being fully complied with;

• Ecologists, who will ensure that pre-construction surveys are carried out and ecological mitigation measures are implemented; and

• Archaeologists, who will monitor soil removaland excavations for unexpected archaeologicalfinds.

How will safety and security beensured?Great Britain’s high-pressure natural gas pipelinesystem has been in operation for more than 35 yearsand has an excellent, well-established andinternationally recognised safety record. Thepipelines are designed, constructed, operated andmaintained in accordance with the Institution of GasEngineers and Managers guideline: Steel pipelinesfor high-pressure gas transmission (IGE/TD/1: LatestEdition). This is the recognised industry standardand, in addition, National Grid has a set of standards

and procedures that underpin and complement thelatter guideline. These standards and procedureshave been developed over many years and havebeen fully accepted by the Health and SafetyExecutive.

The pipelines will be all welded construction with100% of the welds subjected to non-destructivetesting using either radiography, ultrasonics or acombination of the two. In addition, the completedpipeline sections are subjected to hydrostatic test toapproximately 150% of the maximum operatingpressure to check the pipeline’s integrity prior tocommissioning to gas.

Once a pipeline is operational, National Grid carriesout a strict and thorough programme of inspectionand maintenance so that its high safety standardsare upheld. The operation of the commissionedpipeline will be monitored from the National GasControl Centre. It is also over-flown regularly tocheck for any potential third party infringements.Monitoring of pipe condition, including changes inpipe geometry, is carried out at pre-determinedintervals using pipeline internal gauges, asophisticated technology first developed in the UKand now used throughout the world. This allows aninternal inspection device of great sensitivity to beinserted into the pipeline and be transported alongby the gas velocity itself. This allows National Grid toanalyse, and ultimately plan and rectify, any featureswhich may affect the pipeline’s integrity. In addition,the pipeline’s highly durable protective coating isenhanced by an electrical cathodic protection systemwhich ensures that the pipeline remains corrosionfree.

Safeguarding the environmentHow will the surroundingenvironment be affected? The gas pipeline route is carefully selected tominimise its environmental effect and will beentirely buried below ground; in addition, alldisturbed land will be restored after construction.An environmental assessment of the landscape,wildlife, archaeology, land-use and physicalenvironment (soils, geology, hydrology, etc.) hasbeen undertaken and is summarised in theEnvironmental Statement. The environmentalassessment has assisted the development of a seriesof measures to safeguard the physical environment,the landscape, nature conservation, water resources,agriculture, archaeological remains and the socio-economic environment. Specialists within thepipeline management teams will continue to work

alongside the construction teams to ensure that allcommitments made to protect the environment areundertaken.

What mitigation measures will beadopted?Physical environmentNational Grid seeks to avoid the most sensitive areasof the physical environment to limit damage anddisturbance to designated geological sites and soils.Areas of mineral resources, suspected contaminatedland and landfill sites are also avoided wherepossible.

The pipeline route avoids geological Sites of SpecialScientific Interest (SSSIs) and other individuallydefined geological sites, with the exception of aGeological Conservation Review site at Cusop Dingle,south of Hay-on-Wye, which will be crossed bytunnelling to minimise disturbance. In addition, ithas not proved feasible to avoid part of the FforestFawr Geopark, established within the BreconBeacons National Park, albeit the pipeline routeavoids the most geologically valuable features. In thisinstance, mitigation will focus on minimising effectson the broader archaeological, landscape andrecreational value of the Geopark.

Particular care will be taken to limit damage to thesoils along the pipeline route, through carefulcontrol of the timing of soil handling and strictadherence to good practice procedures for bothhandling and reinstatement in order to restore thesoils and associated ecological conditions as rapidlyas possible.

Some steep slopes will be crossed, particularly alongthe western sections of the pipeline route, and carewill be taken to implement a range of measures toprevent soil erosion and sediment run-off, includingthe use of temporary banks, fences and ditches torestrict and limit pollution from water run off inaccordance with industry good practice.

The pipeline route avoids areas of existing mineralextraction and has been routed to minimise thelength within the former South Wales coalfield. Thepipeline route crosses three areas safeguarded forpossible future sand and gravel extraction and anassessment has been made of the implications of this.

The visual landscapeWhilst construction activities will have a short termvisual impact, one of National Grid’s top priorities isto return the visual and physical integrity of thelandscape, as closely and as quickly as possible, to itsprevious condition. Specialist techniques for this

have evolved and improved over the past 20 yearsand are continually being developed. The visuallandscape has been assessed from the perspective oflocal properties, public Rights of Way, roads,recreation and business premises and key touristattractions. The techniques used to minimise thephysical effects on the landscape are generally thesame as those used to minimise effects onagriculture and nature conservation and arediscussed in ‘Nature conservation’ and ‘Agriculture’.

The pipeline route crosses the Wye Valley(designated as an ‘Area of Outstanding NaturalBeauty’) at its narrowest point and avoids the mainfeatures of interest. However, it has not provedfeasible to avoid routeing through the northernextremities of the Brecon Beacons National Park,from Mynydd Myddfai east past Sennybridge toBrecon, and again south of Hay-on-Wye. Thesesections have been the subject of extensiveconsultation and subsequent route refinements tominimise overall environmental effects. However,National Grid acknowledges the broader speciallandscape, recreational, ecological and historicalvalue of the Park and will work with the BreconBeacons National Park Authority to minimise effectson these values and ensure enhancement is in linewith National Grid’s statutory duties.

Whilst the pipeline has been routed to avoid allRegistered Historic Parks and Gardens, it does passthrough areas registered as Landscapes ofSpecial/Outstanding Historic Interest by Cadw andthrough a number of unregistered historic parks andgardens. Where it passes close to the Registered

The landscape of the Wye Valley ‘Area of OutstandingNatural Beauty’ looking south from Strangfordtowards Ross-on-Wye. The pipeline route is down theslope, out of view. The River Wye (in the picture) will becrossed by drilling or tunnelling under the river to avoid anydirect disturbance.


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Historic Parks of Penoyre Park (near Brecon),Penpont (between Brecon and Sennybridge), HayCastle (Hay-on-Wye) and through other notedhistoric parks and landscapes, the pipeline route hasbeen selected to minimise the effects on keyfeatures underpinning the value of these parks andhistoric landscapes.

The assessment of landscape importance andsensitivity not only considers statutory landscapedesignations, such as the Brecon Beacons NationalPark, but also takes into account other values tosociety, which may be expressed by the localcommunity or consultees, such as the scenic quality,unspoilt character, sense of place and conservationinterest. For example, note has been taken of anumber of landscape areas including the LlwchwrValley, Tywi Valley, Wye Valley (near Three Cocks)and the Golden Valley which have been designatedby the local authorities for their locally importantlandscape character or quality.

The landscape and visual assessment has alsoconsidered specific landscape elements and featuressuch as trees, woodlands, hedgerows, meadows,landform and topographic features, river corridorsand other water bodies, and built elements such asdrystone walls.

Improved agricultural land (this is land which issown with an agricultural grass seed mix andfertilized to ensure good grass productivity or isunder arable cultivation) is the easiest to reinstatethrough restoration of existing land drainage,careful soil handling and re-seeding and cultivation.

The pipeline route in these areas is largely restoredto its original visual appearance in the immediatemonths following pipeline construction, with theexception of the boundary hedgerows that takelonger to re-establish.

Unimproved grassland, marshy grassland, heathlandand bog are more difficult and time-consuming toreinstate and have been avoided by pipelinerouteing as far as possible. However, the pipelinedoes cross four areas of upland common of whichthe longest (4km) is within the northern limits of theBrecon Beacons National Park at Mynydd Myddfaiand Mynydd Bach-Trecastell, south-east ofLlandovery. The measures to be taken to ensurerestoration of these sites are described in ‘NatureConservation’.

Wherever possible, the pipeline has been routed tominimise hedgerow removal including routeingthrough gaps or weak/thin points in hedgerows. Allhedgerows will be replanted afterwards usingindigenous species. Drystone walls will bedismantled, stored and replaced after constructionand hedgebanks reformed.

Significant effort has been made to avoid routeingthrough woodland, particularly ancient woodland.Where this has not been feasible, the pipeline hasbeen routed to minimise the need to remove maturetrees and aligned to make use of existing gaps suchas tracks and rides. In several instances, tunnelling(non open-cut methods) of watercourses or railwaylines has been lengthened to cross under adjacentwoodlands to limit tree removal to a strip neededfor plant and machinery access. The total linearlength of woodland crossed by the pipeline route isslightly less than 1.8km, of which nearly one third(0.5km) will be crossed by tunnelling. The visual andlandscape effects of crossing these woodland beltshas been assessed and used in the development ofmitigation measures. The pipeline also crosses otherareas of semi-natural vegetation includingwatercourses and tree-lined lanes and tracks. Suchfeatures form important visual focal points alongthe route and so vegetation removal will beminimised, banks reinstated and trees replanted.

Where tree removal is unavoidable, four trees willbe replanted for every one removed. However, aslarge tree species are not planted directly overpipelines there will remain a limited visual landscapeeffect at some of these locations.

Nature conservationThe potential effects of the proposed pipeline onecology have been identified through acomprehensive desk-based assessment, consultations,walkover surveys and an extensive programme offollow-up surveys. This has provided detailedinformation on potential constraints associated withimportant features and species of natureconservation value along the pipeline route.

The pipeline has been successfully routed to minimiseeffects on important species and habitats; and site-specific mitigation measures will be undertakenwhere valuable areas cannot be avoided. Theseinclude:

WatercoursesSeveral watercourses crossed by the pipeline areinternationally recognised as important wildlife sitesfor their species assemblage, including their fishpopulations, and the presence of otters and white-clawed crayfish. These watercourses will be crossed bytunnelling (non open-cut methods) to minimise directeffects. Other large rivers will also be crossed bytunnelling. Minor watercourses will be crossed bydamming or channelling the water into pipes; thepipe trench can then be excavated in dry conditions.

Where the beds and banks of watercourses aredisturbed these will be carefully reinstated andprotected from erosion while vegetation is re-established. The crossing methods adopted for allwatercourses will be agreed with the EnvironmentAgency (England and Wales) prior to the start ofpipeline construction.

Valuable grasslands and bogsWhere such areas are crossed, site-specific measuresare proposed to minimise damage and ensuresuccessful restoration, these include:

• Reducing the working width;

• Special topsoil stripping techniques to maximisenatural germination when soil is replaced;

• Taking seed cuts of the same or adjacent areasto re-seed the area affected;

• Cutting turves, storing and replacing them afterconstruction;

• Maintenance of the existing drainage patternswhere these are important;

• Permitting natural regeneration where specificconditions allow; and

• Leaving the temporary fencing, installed eachside of the working width during construction,in place for as long as necessary to achieve therequired restoration to the satisfaction of theconsultees and landowners/occupiers.

The pipeline has been routed to avoid large areas ofnative daffodils. Small patches, mostly at field andwoodland edges, may be affected by the pipeline butthese will be carefully reinstated followingconstruction.

HedgerowsMeasures to minimise damage to hedges crossed bythe pipeline include:


• Replanting with indigenous, locally sourcedplants;

• Planting nearby gaps in the hedges, whereappropriate and with the approval of thelandowner, to achieve long-term landscape andecological improvement; and

• Translocation of the most ecologically valuablehedges (i.e. the physical removal of the hedgeto a temporary holding area and itsreplacement following construction in itsoriginal position).

Golden Valley looking east from the lane to Snodhill atbrook crossing. Pipeline route runs away from viewer onright hand side of the view.

Mynydd Myddfai and Mynydd Bach-Trecastell. This viewis looking south-east from the Waun Ddu Site of SpecialScientific Interest (SSSI) towards the north-eastern corner ofthe forest above the Usk Reservoir. The pipeline route runsfrom right to left in the middle ground outside the SSSI. Thisarea of common land, within the Brecon Beacons NationalPark, is of ecological, archaeological, landscape andrecreational importance. The route has been subject toextensive consultation and revision in this area to minimiseeffects. Specific construction and reinstatement methods willbe drawn up for approval by the Countryside Council forWales, the Brecon Beacons National Park Authority and othersbefore start of construction.


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WoodlandsWherever possible, the pipeline has been routed toavoid woodlands. In a small number of instances,where woodlands run perpendicular to the pipelineroute, this has not been possible. In each case a site-specific package of measures is proposed tominimise damage and ensure successful restoration.The measures include:

• Special topsoil stripping techniques tomaximise natural germination when soil isreplaced;


• Minor route changes to avoid individual trees;

• Harvesting of young saplings and seedlings touse in replanting;

• Replanting with locally sourced plant materialwhere additional plants are needed; and

• Maintenance of the existing drainage patternswhere these are important.

Important speciesMeasures have been taken to minimise the effect ofthe pipeline on species which are considered to beimportant both nationally and locally. For example,the pipeline has been routed to avoid badger settsand otter holts, and, wherever practical, vegetationremoval will take place outside of the bird nestingseason.

Additional measures taken to protect the mostvulnerable species that may be temporarily affectedby pipeline construction include:

• Fencing the working width to prevent greatcrested newts and reptiles from accidentalinjury during construction;

• Maintaining temporary links across theworking width during construction, andreplanting following construction, to ensurethat bats can continue to use hedges andwoodland belts as ‘flight corridors’;

• Careful clearance of hedges and woodlandwhere dormice may be present, encouragingthem into neighbouring habitat whereadditional dormice tubes and boxes have beeninstalled;

• Accelerated reinstatement ofhedges used by dormice and bats;

• Providing lines of deadwood foruse by dormice as pathways acrosshedgerow gaps made by thepipeline route while replacementhedge plants become established;

• Using non open-cut methods tocross those rivers designated asinternationally important, mainlyfor their populations of fish, ottersand white-clawed crayfish;

• Conducting fish rescues whenopen-cut methods are used to cross watercourses;

• Capture and transfer of white-clawed crayfish away from theimmediate working area at open-cut river crossings to avoidaccidental injury duringconstruction, together with other mitigation measures;

• Careful dismantling of log pilesand other potential ‘refugia’(features used for resting orhibernation); moving any reptilesaway from the working area,together with other mitigationmeasures, as appropriate;

• Retention of cut hedge material,where appropriate, to enable thecaterpillars of the brown hairstreakand white-letter hairstreakbutterflies to emerge andreplanting of the hedge sectionremoved with appropriate species;and

• Implementation of appropriategrassland reinstatement wherepotentially valuable sites for marshfritillary butterflies have beenidentified, with the approval of thelandowner.

Once the pipeline construction has beencompleted, additional surveys will beundertaken to monitor the progress ofreinstatement of important habitats andspecies which may have been affected bythe construction of the pipeline.

A lesser horseshoe bat. The pipeline route passes close to a numberof important bat roosts and the hedgerows and woodland belts crossedby the pipeline are, in these areas, often important as flight-lines forbats. These flight-lines will be maintained during construction andvegetation reinstatement accelerated, where appropriate.

A dormouse. Populations of dormice occur in several areas along thepipeline route. Vegetation will be removed carefully before constructionto avoid injury. Hedgerows and woodlands used by dormice will bereinstated with the needs of dormice in mind and opportunities takento improve the habitat for them, where appropriate.

A great crested newt. Great crested newts are present in some pondson the eastern half of the pipeline route. None of the ponds will beaffected by pipeline construction but special fencing will be erected toprevent newts being accidentally killed during pipeline construction.

Wet woodland of high nature conservationvalue. This photo shows one of the woodlandscrossed by the pipeline route. This 100m wide area ofwoodland borders the railway line running northfrom Ammanford, which the pipeline crosses to thenorth of Llandybie. Prior to works taking place, a site-specific Environmental Method Statement will beagreed with the Countryside Council for Wales forthis and other valuable woodlands crossed, detailinghow the pipeline will be constructed and how it willbe reinstated after construction. For this wetwoodland site, a non-open cut method, involvingdrilling or boring, will be used to install the pipelineunder the majority of the woodland and the adjacentrailway line, thus minimising direct effects. Treeremoval is likely to be needed, however, where thepipeline emerges at the eastern edge of thewoodland. Mitigation measures, where tree and soilremoval is required at woodlands crossed by thepipeline, are described in ‘Woodlands’.

This site, along with other sites of high natureconservation value, will be monitored over the yearsfollowing replanting, to assess the success ofrestoration. The line of tape marks one of thetransects that has been surveyed in detail to providea baseline against which the success of restorationwill be assessed.


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• Air emissions: emissions from diesel engineswill be kept to a minimum by turning them offwhen not in use and by correct maintenance;

• Dust and mud generation: dust and mud arelargely weather dependent and vary infrequency and location. Water bowsers,sweepers and speed limits will be used tominimise nuisance or hazards;

• Light: the construction site will generally beunlit. Some tunnelling and commissioningactivities may require 24-hour operation.Where this occurs, lighting will be shrouded to minimise disturbance;

• Unplanned emissions and spillage: stringentsite control measures will be put in place aspart of the pollution prevention andemergency response plans, including trainedemergency crews, spill kits and staff training;

• Noise and vibration: noise sensitive areas willbe identified and additional measures taken to reduce noise levels and to maintaincommunication with local residents.

AgricultureNational Grid has national agreements with UKfarming and landowner organisations. These detailoperational methods and minimum standards ofworkmanship for the construction and operation ofpipelines and the reinstatement of land.

National Grid is committed to:

• Consult with landowners and commoners tohelp resolve any problems;

• Take precautions to prevent damage andinjury to land, buildings, fences, stock, cropsand the general environment;

• Make good any loss or damage;

• Take precautions to prevent the spread ofanimal and plant diseases;

• Protect and repair land drainage;

• Protect water supplies; and

• Ensure that reinstatement is in accordancewith the objectives of any agri-environmentscheme. These are schemes designed toenhance the ecological value of agriculturalland, such as Tir Gofal in Wales andEnvironmental Stewardship in England.

Particular care will be taken to ensure thatreinstatement of land in agri-environment schemesis in accordance with the objectives of that scheme.

Where replacement land drainage schemes arerequired and the existing drainage pattern hashelped create valuable ecological habitats, both onand off the pipeline route, care will be taken toensure that existing groundwater drainage patternsare maintained.

ArchaeologyNational Grid has conducted an extensiveprogramme of archaeological surveys to identifyknown and potential archaeology along thepipeline route. The surveys undertaken consist of:

• Archaeological Desk-based Assessment;

• Archaeological Field Reconnaissance Survey(including archaeological line walking to allowfor specialist advice in the field whendetermining the pipeline route);

• Archaeological Earthwork Survey;

• Archaeological Field Walking Survey;

• Archaeological Geophysical Survey;

• Archaeological Metal Detection Survey; and

• Archaeological Trial Trenching.

These surveys have been used to develop themitigation measures described within theEnvironmental Statement. These measures are inaccordance with nationally recognised standardsand will be further developed and approved by therelevant Local Authority Archaeological Officers andthe Welsh Archaeological Trusts. The mitigationmeasures include:

• Preservation in-situ of sensitive archaeologicalremains through a combination of localisedvariations to the route, reducing the workingwidth, protective matting and carefulreinstatement procedures;

• Excavating the site where preservation in-situis not desirable or feasible. The findings arereported fully to preserve, by record, thearchaeological value of the site; and

• Employing qualified archaeologists to monitortopsoil and sub-soil removal to identify andrecord any previously unrecorded archaeologydiscovered during construction.


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Water resourcesA study of the hydrology and hydrogeology hasbeen undertaken to identify potentialenvironmental constraints such as aquifers, existingwater abstraction and discharge points, flood plains,watercourses, rivers at risk of pollution fromsediment run-off, habitats which are particularlysensitive to changes in groundwater levels, springsand private water supplies.

Mitigation measures will be adopted to minimiseboth temporary adverse effects during constructionand longer-term effects on water resources. Thesewill include:

• Constructing temporary bridges acrosswatercourses;

• Minimising surface water and sediment run-offthrough use of a range of measures includingtemporary banks, fences, ditches, etc. to trapsoil and restrict and limit pollution inaccordance with the latest good practiceguidance to the construction industry;

• Careful reinstatement of watercourse banks toprevent future erosion and instability;

• Preventing contamination of watercourses andgroundwater through applying stringent on-site pollution control measures;

• Applying strict controls over the pumping anddisposing of water from excavations;

• Careful planning of hydrostatic pressuretesting;

• Implementing flood prevention measures andtemporary dewatering systems in floodplains(dewatering involves the installation oftemporary drainage pipes, dischargingthrough settlement tanks, as necessary, tomanage the level of water entering the pipetrench or other excavations);

• Including barriers in the pipeline trench toprevent it acting as a conduit forgroundwater; and

• The monitoring of spring fed and privatewater supplies before, during and afterconstruction.

The pipeline passes close to public water suppliesnear Vowchurch in the Golden Valley, Herefordshire.The British Geological Survey has been appointed toundertake surveys to identify and assess the effectson the aquifer and water supplies and to propose

mitigation measures. This will include production ofa computer model of the hydrogeology of theaquifer and the effect of pipeline construction (if any).

EmissionsAn assessment of the effects of emissions is providedwithin the Environmental Statement and includeswastes, liquid effluents, releases to air and spillages.Emissions are almost entirely confined to theconstruction stage and will be minimised by carefulplanning and management as summarised below.Close liaison with relevant parties, such as LocalAuthority Environmental Health/Protection Officerswill be maintained throughout construction.

• Hazardous and non-hazardous wastegeneration: a waste management plan will be prepared to control waste production,storage and disposal. Materials will be recycledor re-used where possible and waste needingdisposal will be stored in suitable containersand removed off site;

• Water discharges: see ‘Water resources’;

The view from Dynevor Castle over the Tywi valley. Thepipeline route runs parallel to the Tywi within the floodplainon the far bank. The location of the topsoil storage moundsneeded during construction will be agreed with theEnvironment Agency Wales (EAW) to minimise flood risk. Thedesign of any temporary drainage system to controlgroundwater during construction will also be agreed withthe EAW. The topsoil will be replaced and the grassland re-established as soon as possible after pipeline construction.The pipeline route should be fully reinstated, and the routeof the pipeline no longer visible, the summer afterconstruction. The castle is open to the public. National Gridwill work with the National Trust, Cadw, Tourist Offices andthe National Park to ensure information for tourists,businesses and local communities is managed effectively.


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National Grid is mindful of the need to minimisetemporary negative impacts on local communitiesfrom traffic and to minimise impacts on tourism andrecreation both during and after pipelineconstruction. This is particularly important in theNational Park, where there may be both directeffects, for example on walkers, and indirect effectsfrom the perception that the special qualities of thearea have been affected.

During pipeline construction, public Rights of Waywill be kept open wherever practical and all will befully reinstated upon completion. Informal rights ofway and patterns of access, e.g. on common land,will be identified with the help of local groups andused to plan temporary access points across thepipeline construction area. Public Rights of Way andother important paths may be diverted and signedwhere necessary.

A project communications plan will ensure that,through timely communications, communities,businesses and local residents will be informed ofconstruction works and associated activities thatmay affect them throughout the lifetime of theproject. The communications may include sitesignage, targeted letter-drops, individual meetings,local exhibitions and information provided to thelocal press and media. A freephone telephoneinformation line (0800 731 0561) has beenestablished and will be maintained to providefurther access to project information.

Through consultation with the Brecon BeaconsNational Park Authority, Local Authorities, theEnvironment Agency (England and Wales) andothers, the communications plan will identify whereeffects on tourism may occur to ensure thatappropriate and timely information can be providedon pipeline construction and restoration. This willaim to provide reassurance about the effects thatthe pipeline may have and how these effects will beminimised.


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Traffic and transportSignificant traffic will only be generated during theconstruction phase and good practice mitigationmeasures will be applied to minimise effects. Theseinclude:

• Production of traffic management plans, inconsultation with local Highways Authoritiesand local Police;

• Crossing under main roads by tunnelling tominimise disruption;

• Minimising the distance travelled by roadusing local sources of equipment andmaterials;

• Minimising the generation of waste by reusingand recycling;

• Using the pipeline working width to moveequipment along the route;

• Avoiding narrow and restricted roads fortraffic movements;

• Plans to minimise impacts on tourist traffic,especially during holidays and when eventssuch as the Hay-on-Wye festival are takingplace; and

• Imposing local time restrictions onconstruction pipe and plant movements wherenecessary.

The level of temporary effects on communities,businesses and tourism will be carefully assessedalong the pipeline route and used to identify whereadditional liaison and communication is needed.National Grid will liaise with the Brecon BeaconsNational Park Authority and Local Authority tourismofficers to ensure that effects on promoted routesare minimised.

Socio-economic environmentThe pipeline is an important element in securing theUK’s future energy supplies. It will also help the UKmeet its commitments to reduce greenhouse gasemissions as part of efforts to minimise climatechange. At a regional level, increased availabilityand security of gas supply will enhance the potentialfor growth in the Welsh economy. At a local level,the demand for goods, services and staff duringconstruction will have a beneficial effect on the localeconomy.

National Grid recognises that, in order tominimise the effect of the Felindre to Tirleynatural gas pipeline, there are a significantnumber of mitigation measures that need tobe implemented across all aspects of theproject. To achieve this, National Grid willensure that the mitigation measures aredeveloped into achievable working practicesand, most importantly, that these workingpractices are undertaken at the appropriatetimes in conjunction with the constructionprogramme. These mitigation measures andworking practices will be disseminated to allstaff working on the project.

The result will be that the environmentaleffects of the pipeline are minimised. Themajority of the pipeline route will be restoredto its pre-existing visual appearance within the immediate months following pipelineconstruction. Other areas such as marshygrassland, upland grassland and heathland,newly replanted hedgerow sections andwoodland belts, will take longer to mergewith the existing vegetation. A programme of post-construction ecological managementwill be implemented to ensure successfulrestoration throughout the pipeline length.

Conclusion

A full programme of archaeological surveys is undertakenbefore the commencement of pipeline construction. One ofthe surveys carried out is geophysical survey usingmagnetometry. This method detects possible archaeologicalremains through analysis of local changes in the earth'smagnetic field. Potential archaeological remains wereidentified along a section of the pipeline route to the west ofLlangadog and this area was targetted for investigation. Atrial trench (one of over 250 such trenches along the pipelineroute) was excavated as shown in the photograph. In thiscase, an archaeological feature, believed to be a 15th/16thcentury brick kiln, has been identified and is visible in thephotograph. Mitigation measures for this site and othersidentified will be discussed and agreed with the relevant Archaeological Trust or Local AuthorityArchaeologist before start of construction.

environmental statement · intermediate pig-trap near three cocks, powys this pig-trap installation...

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