king street gas storage project (pipelines): non … · other elements of the overall king street...

King Street Energy King Street Energy Gas Storage Project - Pipelines Environmental Statement

MWH UK Ltd 41514271/Non Technical Summary Rev03 NTS-1

KING STREET GAS STORAGE PROJECT (PIPELINES): NON TECHNICAL SUMMARY

Introduction

King Street Energy (Cheshire) Ltd (‘KSE’ or ‘the Applicant’) proposes to develop a site at King Street, near Northwich, Cheshire for the purposes of storing natural gas. As part of this project, it is proposed to construct two parallel pipelines, each of about 800mm internal diameter and approximately 58km long, for transporting water from the Mersey Estuary at Bromborough, to King Street, and returning the saltwater produced from the solution mining process back to the Mersey Estuary.

Other elements of the overall King Street Gas Storage Project, but not covered here, involve the development of ten underground salt cavities through the process of solution mining on the King Street site, and the construction of a gas processing facility for the storage of natural gas in the underground salt cavities. These other elements are the subject of a separate application (Planning Application No. 4/07/2486/FZ5) and Environmental Impact Assessment (EIA).

An EIA has also been undertaken for the proposed pipelines element of the project to identify, assess and mitigate the impacts of its construction and operation on the existing environment. The EIA also looks at the need for the project and its design. This document is the Non Technical Summary (NTS) of the Environmental Statement (ES) and provides a brief description of the proposed development and the findings and conclusion of the EIA.

Further copies of the NTS are available free of charge from the Applicant upon written request, at the following address:

Simon Towers King Street Energy (Cheshire) Ltd Fyfe Chambers 105 West George Street Glasgow G2 1PB

Hardcopies and CD-ROM copies of the ES Volumes are available for purchase from the above address, also upon written request. The cost for a hardcopy of the ES is £650.00, and £30.00 for CD-ROM. Alternatively, the ES and NTS can be downloaded from www.kingstreetenergy.com.

The Project

The estuary water and saltwater pipelines will connect the King Street site, located to the south east of Northwich, with the proposed abstraction and discharge points in the Mersey Estuary near to Bromborough on the Wirral peninsula, as shown in Figure 1.

The project comprises the pumping of untreated estuary water from an intake pumping station in Bromborough to the gas storage location at King Street. The intake pumping station will have a fine screen on the inlet pipe to prevent ingress of large solids and marine life. The pumping station structure will be constructed below existing ground levels, with an above ground control building and associated infrastructure. An intermediate booster pumping station will be required at Frodsham. This facility will comprise an above ground break tank with pumps and associated equipment housed in low-rise buildings.



Figure 1: Proposed Pipeline Route

The saltwater used to create the underground salt cavities will discharge into a pumping station tank located at the King Street site. The saltwater will then be pumped back along the second pipeline to Bromborough. This pipeline will also require an intermediate pumping station at Frodsham, similar to that provided for the estuary water pipeline.

The estuary water and saltwater pipelines will, for the most part, be constructed in an open trench. At major infrastructure crossing points tunnelling techniques will be employed to minimise disruption. The construction working corridor will be nominally 30m wide, but increasing where tunnelling set-up establishments are needed or where the presence of other underground services may dictate. At sensitive locations such as hedgerows, brook crossings etc., the working corridor width will decrease.

The saltwater pipe will run to a discharge site in the bed of the Mersey Estuary. The abstraction intake and discharge outfall locations are shown in Figure 2.

From west to east, the pipeline route runs south out of Bromborough and Eastham, passing to the west and south of Ellesmere Port on a course roughly parallel to the M56 motorway. The route continues to the north of Helsby and Frodsham until it reaches the River Weaver. At this point, the route turns in an approximate south easterly direction, heading towards Kingsley, Acton Bridge, Onston, and Bryn. The route passes to the east of Sandiway and continues in an approximate south easterly direction towards the village of Moulton. At Moulton, the route turns in a general north easterly direction, heading towards Rudheath and King Street.



Figure 2: Proposed Abstraction and Discharge Points

History of the Project and Consideration of Alternatives

The King Street Gas Storage Project was first proposed in late 2002. For much of the subsequent four years, the Applicant sought to find ways of exploiting the King Street asset through “salt for water” swap arrangements with local companies similar to those planned, at the time, for other, similar projects nearby. When all such avenues had been exhausted unsuccessfully, the applicant approached the Environment Agency in late 2006 with a view to abstracting solution mining water from the Mersey estuary and then returning the salt water for discharge into the estuary. Early discharge simulation by computer modelling has suggested that the volumes, about 60 million litres per day (60Ml per day), should not be a problem for the estuary. This is the development route now being followed

Abstraction and Discharge Locations (Mersey Estuary) To identify potential abstraction and discharge locations within the Mersey Estuary, a review was undertaken of existing Abstraction Licences and Discharge Consents with the aim of:

• Identifying whether any existing infrastructure could be effectively used by this project;

• Identifying other major abstraction and discharges which may conflict with an abstraction / discharge for this project; and

• Identifying new potential abstraction / discharge location(s) for this project.

The search area for this exercise was the Mersey Estuary between Wallasey, on the Wirral, and Runcorn, determined as the most suitable region to abstract and discharge the volumes of water



required. In spite of there being many and varied licences and consents, there was no combination suitable for use by this project and it was decided to investigate the construction of a new intake from and outfall into the Mersey Estuary.

From the discussions with the Environment Agency, the preferable location for the construction of the new intake and outfall was on the North Wirral coastline, between Bromborough and Eastham. Due to the developed nature of the coastline it was not possible to identify potential abstraction and discharge locations beyond the boundary of the Mersey Estuary Site of Special Scientific Interest (SSSI).

Pipeline Route Corridor

As part of the study to identify the preferred route corridor for the parallel pipelines the following considerations and criteria were take into account:

• Avoidance, where possible, of statutory and non-statutory environmental and archaeological designations, and other features of environmental significance;

• Avoidance, where possible, of potentially difficult construction areas such as side slopes, complex river crossings etc.;

• The avoidance, as far as possible, of centres of population and individual isolated properties;

• The crossing of rivers, major roads and railways at right angles, wherever possible;

• The safe access for construction vehicles, and the health and safety of construction personnel; and

• The shortest distance between the start and finish points of the pipelines bearing in mind the above.

A route selection methodology based on the above environmental, engineering and geotechnical considerations and constraints involved the following stages:

• Definition of Area of Search – based on the start and finish points of the pipeline, and aimed to cover all practicable routes between these points;

• Corridor Selection – information was gathered on the geography and environment of the search area and used to identify 1km wide potential route corridors which would allow flexibility as more data became available. This allowed the identification of a preferred corridor;

• Preliminary Route Selection – The preferred corridor was then assessed in greater detail so that a preliminary route within the corridor could be established;

• Route Refinement and Environmental Impact Assessment – Route refinement continued as detailed environmental and engineering survey information became available, and as the EIA was undertaken.

The route corridors identified are shown in Figure 3. Route Option 1B, the route from Bromborough, passing to the north of Frodsham and to the south of Northwich, was concluded to be the preferred option as it contained the least number of environmental and engineering constraints, in terms of topography, the number of major crossings, and overall length.



Figure 3: Route Corridor Options

Construction of the Pipelines and Associated Structures

Construction will involve the following activities:

• Construction site clearance, to include tree felling, hedge grubbing and other vegetation removal at the most appropriate times of year in order to minimise impacts on species.

• Establishment of areas for temporary compounds for pipe storage and site offices; to be located at King Street, Northwich, adjacent to Junction 14 of the M56, and adjacent to Junction 5 of the M53.

• Fencing of the pipeline route working corridor area.

• Stripping of topsoil. Topsoil and subsoil will be stored separately within the working corridor.

• Construction of the pipeline. Open trench excavation will be used to lay the parallel pipelines, although tunnelling techniques will be used at certain river, canal, road and rail crossings, as well as beneath Long Plantation, within Eastham Country Park. Wash-outs, air-valves and isolation valves will also be installed within small chambers at points along the pipelines. Existing services crossed by the pipelines will be protected during the construction. Land drainage will be installed in the working corridor to assist or temporarily replace existing land drains.

• Reinstatement. The following principles will be applied:

− all soils will be replaced in the reverse order in which they were excavated, ensuring topsoil is replaced on the surface;

− re-seeding will be undertaken with seed mixes agreed with landowners;

− all planting, including any landscape planting, will be undertaken with native species, locally sourced wherever possible;



− where trees have been removed during construction, two trees (or more) will be planted for every one removed, with landowner approval and subject to planting restrictions;

− hedgerow sections removed will be reinstated with an appropriate mix of species, using locally sourced plants where possible;

− any land drains that are temporarily diverted during the construction process will be reinstated;

− existing fences will be reinstated;

− river crossings will be reinstated to as close as possible to their original condition;

− Public Rights of Ways and other footpaths, diverted or temporarily closed in accordance with the necessary approvals, will be reinstated to their original alignments; and

− crushed or recycled concrete bases of the temporary access points will be removed and the sites reinstated and re-seeded as above.

• Construction of the Pumping Stations. The Bromborough pumping station facility is to be built on derelict land at Commercial Road and will involve the demolition of existing buildings and construction of underground and above ground structures. Two brick buildings will house control and electrical supply equipment. Other above ground structures include two transformers and a steel surge vessel. All structures will be within a 2.4m high steel security fence.

At Frodsham the two intermediate pumping stations will be located at the East Clifton landfill site within a single compound surrounded by security fencing. For each station the the pumps will be housed within a single storey brick clad building. Brick buildings will house electrical and control equipment and compressors. Located between the pumping stations will be two 6m high above ground tanks approximately 48m and 23m diameter. A surge vessel will be provided for each pipeline.

• Construction of the Marine Works. These works comprise an estuary water intake structure and intake pipeline, and an outfall pipeline including a diffuser section. The pipelines will both be constructed below the estuary bed level by the ‘directional drill’ tunnelling technique. Excavation from the bed level will only be needed for the intake structure and diffuser section of the outfall. The intake structure will be located approximately 120m offshore of the Bromborough pumping station site and will comprise a concrete caisson topped with a 6mm wedge wire screen. The 1300m long outfall will terminate in the Middle Deep channel approximately 800m offshore. The diffuser will be approximately 160m long with vertical pipes protruding 2m above estuary bed level. These ‘risers’ will be protected with pre-cast concrete domes and rock armour will be provided along the length of the diffuser to mitigate against scouring by the estuary currents.

Working Hours

Construction works will mostly be undertaken within the following working hours:

• Monday to Friday 7.30am to 6pm; and

• Saturdays 7.30am to 1pm.

Working outside these time restrictions may have to be undertaken for specific activities such as at road or river crossings. Work outside the above times will only be undertaken with prior approval and after giving notification to nearby residences and businesses, stating the reason for the activity and the likely duration.



Special Crossings

Where major infrastructure such as motorways and railways are to be crossed, specialist tunnelling techniques such as ‘directional drilling’ and ‘micro tunnelling’ will be used to avoid surface disturbance and disruption. These ‘special crossings’ will be undertaken at 29 locations, including all motorways, major roads and rivers, railways and canals.

Construction Vehicles, Plant and Machinery Main construction activities will be undertaken using large tracked excavators and dumper trucks. Deliveries of pipe sections and aggregates for pipe bedding will be made by articulated flat bed lorries and tipper lorries.

Traffic Management during Construction A construction Traffic Management Plan (TMP) will be prepared in discussion with Cheshire County Council, Wirral Metropolitan Borough Council (MBC), railway network owners and the Police, and submitted to them for approval prior to commencement of construction works. The TMP will include traffic management and control measures to maintain road and rail safety, accommodate the predicted traffic flows, protect the road structure, and co-ordinate works to minimise queues and delays.

Construction Environmental Management The Applicant acknowledges that Environmental Management is an essential part of the project, during both the planning and design phase, and during construction. They recognise their responsibilities to manage effectively the key environmental issues, including minimising environmental impacts and recognising how activities interact with communities. The planning, of this project has been undertaken in accordance with the aims and objectives set out in their environmental management systems which will continue to be adopted during the design and construction phases.

An important aspect of the project is the production of the Construction Environmental Management Plan (CEMP), to be prepared by the appointed contractor, but reviewed and approved by the Applicant. The CEMP will be implemented and maintained to control environmental performance, and will contain details of the environmental impacts and proposed mitigation measures identified during the EIA process.

Pipeline Operation

Once the new pipelines have been put into service, the creation of gas storage caverns at the King Street site will commence. Operation of the pipelines is anticipated to be for 3 ½ years.

Once in service, the new pipeline will need minimal maintenance, with periodic visits made to check the operation of air valves and washouts on the pipeline. These visits will usually be on foot and during normal working hours. Plant and equipment will only be needed should maintenance operations be required.

Pumping stations will operate automatically with control from King Street, where pump flow and pressure measurements will be monitored on a continuous basis. Weekly on-site maintenance checks will take place at each station.



The abstraction and discharge points within the Mersey Estuary will require visual inspection, initially on a three monthly basis for the abstraction intake and six monthly for the discharge outfall.

Leakage Detection Provision will be made for the accurate detection of leaks in the pipeline, and for shut-downs to facilitate repairs. Isolation of any leak and subsequent repair will be facilitated by manual operation of the line valves closest to the damaged length of pipeline.

Pipeline Decommissioning

Once there are no further uses for the pipelines, they will be decommissioned in accordance with the industry standards pertaining at the time. The estuary abstraction/discharge points will be removed when the pipelines are decommissioned.

Environmental Impact Assessment

The EIA process is governed in the UK by the Town and Country Planning (Environmental Impact Assessment) (England and Wales) Regulations 1999 (‘the EIA regulations’) which implement EC Directive 97/11/EC. The EIA regulations specify what information is to be included in an ES. All of the aspects stated in the regulations have been included, although the level of detail in which each is considered varies depending on the likelihood and significance of the potential effects.

A summary of the assessment is given below.

Geology, Soils and Contamination

The proposed pipeline route crosses a variety of different soil types. The land use tends to be seasonally wet grasslands, typically associated with dairying, and arable, with some woodland. The proposed alignment of the pipeline crosses the very northern extent of the active Gowy Landfill Site, located at Ince Lane, Wimbolds Trafford, Chester. The main area of known contaminated land is at East Clifton Tip, Frodsham, which has a history of landfilling operations. The site is bounded by the River Weaver, Weaver Navigation, the M56 viaduct and railway, and is the proposed location of the Frodsham Pumping Station.

The potential effects of the proposed pipeline development on geology and soils, and from contaminated land, will largely occur during the construction phase, and will be temporary and of short duration. Key potential impacts include:

• Disturbance of underlying geology. In localised areas the solid bedrock may cause hard digging conditions. However, it is considered that there will be no need for controlled blasting, and that mechanical means will be sufficient.

• Disturbance to superficial deposits. The proposed pipeline route cross alluvium and peat deposits at a number of locations which may cause problems during construction. Particular care will be taken to minimise impacts in these areas, including with regard to their reinstatement.



• Disturbance of, and damage to soils. The proposed pipeline route may impact on the fertility of certain soils used for agriculture. In order to minimise impacts to soils, construction activities will be undertaken in accordance with guidance given in the MAFF Code of Good Agricultural Practice for the Protection of Soil, DEFRA’s Controlling Soil Erosion and Section 10 of BS 8010:2004 Code of Practice for Pipelines.

• The potential sterilisation of mineral reserves. The proposed pipeline route crosses areas of minerals extraction, for sand and gravel and rock salt, however no mineral reserves will be sterilised.

• The possible mobilisation of localised areas of contaminated ground. Due to the industrial heritage of some of the areas through which the proposed pipeline route passes, there is the potential for other areas of contaminated land and landfill/waste disposal sites to be encountered. Areas of potential contamination have been identified through desk study, and a programme of sampling and analysis is to be undertaken as part of the Geotechnical Site Investigation in order to confirm the nature and extent of any contamination.

Agriculture

The Agricultural Land Classification (ALC) System is a land grading framework which was first developed by the Ministry of Agriculture in 1966. The system allows agricultural land to be graded from Grade 1 (excellent) Grade 5 (very poor). The majority of the proposed pipeline route crosses agricultural land with classification Grade 3 (good/moderate), with only small proportions of Grade 4 (poor) and Grade 2 (good) crossed. No ALC Grade 1 land is crossed.

The proposed pipeline route crosses land within agri-environmental schemes, including Environmental Stewardship (approximately 30% is within the Entry Level Stewardship) and Countryside Stewardship. In order to avoid any breaches in the conditions of these agreements, discussions will be held with landowners and farmers to ensure that disruption to any scheme is minimised and also ensure that there are no financial risks.

Japanese knotweed, Himalayan balsam and other non-native land-based and aquatic species have been identified within close proximity to the pipeline working corridor. A strategy will be developed and implemented prior to the construction phase to manage their presence. This will ensure appropriate treatment of invasive weeds in advance of construction in accordance with approved methodology and will prevent the spread of the species within and outside the working area. This strategy will form part of the overall CEMP.

Impacts and disruption to agriculture during construction will be minimised with the implementation of mitigation measures including: consultations with each landowner/farmer to identify appropriate measures, pre-construction Condition Surveys to ensure reinstatement of all features to their original condition; compensation for the loss of crops and loss of grazing; and the provision of temporary stock-proof fencing, gates and stiles, to facilitate continued access. Reinstatement will include measures to ensure no long-term effects on grazing, crop yield and quality.

Landscape and Visual Impact

There are no nationally designated National Parks or Area of Outstanding Natural Beauty within the pipeline route corridor. The proposed pipeline route does pass through Areas of Special County Value (ASCV) for Landscape and Areas of Special Local Environment Value (ASLEV).



No nationally registered historic parks and gardens are located within the pipeline route corridor. The nearest park of local interest, Vale Royal Park, lies within 500m. The park includes Vale Royal House, a Grade II* country house based on a Cistercian Abbey and is one of a number of Scheduled Monuments.

Conservation Areas within 500m of the proposed pipeline route include: Eastham Village; Frodsham (Town); Onston; Sandiway; and the Trent & Mersey Canal. The proposed pipeline route runs within the boundary of the Eastham Village Conservation Area to the north east of the village. The canal will be crossed by the proposed pipeline route, using trenchless techniques, to the south of Rudheath. The other Conservation Areas are unaffected.

Other relevant landscape policies within the area include the Mersey Forest, and the Mersey Waterfront and Weaver Valley Regional Parks.

Landscape and Visual Impacts of the Proposed Pipelines

The temporary impacts on landscape during construction will vary depending on the sensitivity of the receiving landscape, the key landscape features affected and the degree of enclosure. The most significant landscape features to be affected are the hedgerows and associated hedgerow trees. Such linear features are impossible to avoid and pipeline construction will require the removal of short sections of hedgerows, fences and walls at field boundaries and road crossings. In the medium term, the visual impact of the proposed pipeline route on hedgerows will be limited to these boundary features, although the impacts will be minimised by reducing the gap created, wherever possible, and their replanting following construction. However, it may take five or more years for the replanted sections of hedgerows to establish sufficiently to match the adjacent sections of hedge. Fences and walls will be restored immediately.

Other distinct landscape features include the major watercourses of the Shropshire Union Canal, the River Gowy, the River Weaver and Weaver Navigation, the Valeroyal Cut, the River Dane and the Trent & Mersey Canal. However, all will be crossed using trenchless techniques.

The scale of construction impacts to the landscape and particular landscape features will be minimised by the implementation of mitigation measures which include rapid reinstatement in sympathy to the character of the landscape, and the minimisation of the duration of that impact.

The main visual impacts of the proposed pipelines will be limited to the construction phase when the working corridor, with associated earthworks and construction plant movements, will be visible within the landscape; and for a short period after construction until the reinstated land use and landscape features have established sufficiently to merge with the surrounding landscape.

Landscape and Visual Impacts of the Pumping Stations

The pumping station site at Bromborough will not have any adverse effect on any significant landscape features as the site is well screened and its location within an established industrial area is in keeping with the character of the landscape setting.

The proposed mid-point pumping facility at Frodsham will be located on derelict land within an area which is industrial in character with existing prominent structures including the M56 motorway bridge over the River Weaver to the north west and the railway viaduct at Frodsham Bridge to the south east. Construction may require the loss of some tree and scrub vegetation and the proposed development will be visible at close proximity from recreational paths and facilities. Opportunities for landscape schemes are limited but will be designed to provide screening from areas where the site is most visible, such as recreational paths and Weaver Sailing Club.



Archaeology and Cultural Heritage

In general, the route crosses few known sites and none are known to be of more than local significance. However, the absence of known sites is unlikely to be representative of the true pattern and much of the route has the potential for the presence of previously undetected deposits.

Only one area of further assessment is required in advance of construction works. An area north of Onston will be subjected to a programme of systematic fieldwalking to allow detailed mitigation options to be produced.

In general, mitigation for most known features will be accommodated within a watching brief, concentrated on the known sites and conducted in accordance with project design or method statements agreed in advance with the Cheshire County Archaeological Curators.

No Scheduled Ancient Monuments or Registered Historic Parks or Gardens are directly affected.

The only Listed Building which may be directly affected is the Vyrnwy aqueduct which is a Grade II structure. Works in this area do not require Listed Building Consent.

The only Conservation Area directly affected is the Trent & Mersey Canal Conservation Area. Despite the proposal to undertake the crossing of the Trent & Mersey Canal using trenchless techniques, English Heritage will be consulted with regard to proposed works within this area and detailed mitigation proposals will include details of the proposed construction methodology for this section.

Ecology

The Mersey Estuary, a designated Site of Special Scientific Interest (SSSI), Ramsar site and Special Protection Area (SPA), is directly affected by the pipeline route. It is an internationally important wildfowl and wader site with a range of important coastal habitats, particularly the large areas of sand and mudflats exposed at low tide. The estuary is also a valuable staging post for migrating birds in spring and autumn. No other SSSIs which are directly impacted, although Warburton’s Wood SSSI lies adjacent to the route.

Five non-statutory Sites of Biological Interest (SBI) are crossed by the pipeline route, two of which will be crossed using tunnelling techniques and will not be directly affected. Those directly crossed are the Gowy Meadows and Ditches, the Frodsham and Helsby and Ince Marshes, and East Clifton Tip at Frodsham.

With regard to habitats and protected species, the following surveys have been undertaken during the EIA to supplement the ecological data, records and information obtained:

• Phase 1 Habitat Survey;

• Hedgerow Survey;

• River/Stream Corridor Survey;

• Breeding Bird Survey;

• Badger Survey;

• Bat Survey;

• Water Vole Survey;

• Otter Survey;

• Reptile Survey;

• White Clawed Crayfish Survey;

• Dormouse survey; and

• Invertebrate Survey.



During the surveys, consideration was also given to other potentially important species, including brown hare. All survey work was undertaken between February and October 2007, and generally completed during the most appropriate survey periods using standard survey methodologies agreed in advance with Natural England and the Environment Agency.

The majority of the pipeline route crosses arable farmland and improved permanent grassland. Sensitive habitats are generally avoided, although occasional areas of interest are crossed. A small number of semi-improved grasslands are crossed, and impacts will be addressed through the use of appropriate seed-mixes. Impacts to the grazing marsh habitat crossed by the pipeline will be addressed through detailed method statements, developed in consultation with key nature conservation bodies, with consideration given to the application of a locally derived hayseed concentrate as opposed to standard re-seeding.

Impacts to hedgerows and boundaries will be addressed through the replanting of affected sections with local native species. Mature trees in field boundaries have largely been avoided through minor route realignments, although it is likely that the loss of some mature trees will be inevitable. Further minor route realignments will be made, where possible, following a detailed survey of all trees deemed to be ‘at risk’.

Direct impacts on major rivers and watercourses have been avoided through the use of trenchless crossing methods. Other watercourses crossed will re-colonise rapidly, and efforts will be made to limit disturbance during construction.

The arable farmland and grazing marsh support ground nesting bird species, such as skylark and lapwing. Measures to protect breeding birds will include the use of bird-scaring measures to prevent ground nesting within the working corridor prior to construction, and encourage nesting in neighbouring fields which offer similar suitable breeding habitats. Other potential breeding bird habitats, such as hedgerows, will be removed prior to the breeding bird season to prevent disturbance to birds. Additional enhancement measures, such as the erection of nest boxes, will also be explored.

The pipeline route crosses numerous field ditches and drains, some of which support water vole populations. Mitigation requirements for water vole will be agreed in advance with Natural England, Environment Agency etc., and are likely to include the strimming of bankside vegetation to encourage the species to temporarily move away from the area during construction works. These measures will effectively encourage grass snakes, which may also be present within the ditch network, to temporarily move away. Further surveys will also be undertaken.

Breeding populations of great crested newt (GCN) were identified in 19 ponds. As these ponds will not be directly affected, impacts on GCN are limited to the loss of small sections of hedgerow vegetation through which the pipeline route passes. The pipeline route does pass within 100m of these ponds, requiring a GCN licence to be obtained for the works. Mitigation measures will include the erection of amphibian exclusion fencing and a capture programme to ensure that no GCN are present within the working corridor prior to construction.

Six bat species were recorded during nocturnal activity surveys. Wherever possible, mature trees, which offer potentially suitable bat roosting habitat, have been avoided, however, prior to construction, a survey of all trees deemed to be ‘at risk’ will be undertaken, during which a check for evidence of roosting bats will be made by a suitably qualified ecologist. Where trees are identified as being of importance as bat roosts, felling will be undertaken under the supervision of a licensed bat specialist outside the hibernation period and in accordance with an agreed felling procedure.

No direct mitigation is considered necessary for white-clawed crayfish under the current proposals, although a pollution control strategy will be implemented for all watercourses that



link directly to the River Weaver and River Dane to ensure that no run-off or siltation is washed downstream. Otters are very rare in Cheshire and no specific mitigation is merited, although further surveying at one potential location will be undertaken in 2008. Some precautionary mitigation for brown hare will be undertaken at locations known to support breeding hares.

The abstraction intake and discharge outfall into the Mersey Estuary have been carefully designed to minimise impacts to the aquatic ecology of the estuary. The abstraction intake has been designed to minimise the trapping of juvenile fish. The discharge outfall has been designed and located to ensure a high initial dilution and dispersion of the saltwater discharge within a relatively short distance from the outfall diffuser risers. Impacts on phytoplankton, macroinvertebrate communities and fish within the Mersey Estuary are considered to be negligible.

3-dimensional modelling of the saltwater discharge to date, shows that no increased salinity levels will be experienced by the sand and mudflat exposed at low tide. As such, there will be no impacts to the food species present within these sands and muds and, therefore, no impacts on the bird populations of international importance they support.

Water Quality and Resources

The proposed route of the pipelines crosses numerous ditches/drains, brooks, rivers and canals; 24 of which are Main Rivers maintained by the Environment Agency. The quality of water for the watercourses crossed, where available, ranges from Grade B (Good) for Crowton Brook (Kingsley to Cliff Brook) to Grade E (Poor) for the Shropshire Union Canal, Mill Brook and Hornsmill Brook, as defined by the Environment Agency’s classification system. The western section of the proposed pipeline route, from Bromborough to the Frodsham area, is underlain by a Major aquifer, with two areas of Minor aquifer associated with the River Gowy and the Frodsham, Helsby and Ince Marshes. To the east of Frodsham, the area is largely non aquifer with pockets of Minor aquifer. The proposed pipeline route crosses only one Groundwater Source Protection Zone (SPZ), at Hooton, where it crosses the outer edge of Zone 3 (Total Catchment) for a distance of approximately 200m.

All crossings of major watercourses will be undertaken using tunnelling methods thus avoiding major environmental impacts. Where minor watercourses are to be crossed by excavating from bed level, the crossing points have been selected to avoid the most ecologically sensitive areas, and mitigation measures have been proposed for implementation. These will be further developed in consultation with the Environment Agency, and other interested parties.

No ponds will be affected, as the proposed pipeline route has been designed specifically to avoid these features. However, several ponds are in close proximity to the working width, and protection measures will be implemented to prevent encroachment and pollution.

Sediment run-off is a major risk to watercourses. To prevent impacts from suspended solids, earth moving operations will be undertaken in compliance with Environment Agency Pollution Prevention Guidance (PPG) and construction best practice.

Areas of flood risk crossed by the pipeline route include the Gowy Meadows area, areas of the Frodsham, Helsby and Ince Marshes, and the land between the River Weaver and the Weaver Navigation, and along the River Weaver. To prevent impacts arising during times of flooding, mitigation measures such as the storing of topsoil outside of flood plains will be implemented.



Mersey Estuary

Initial 3-dimensional dispersion modelling has been undertaken to assess the likely impact of the saltwater discharge on the water quality of the Mersey Estuary. The results to date show that the high energy currents experienced within the Mersey Estuary dilute and disperse the saltwater such that the increase in salinity of the receiving water will be kept to low levels. Water quality impacts will be confined to a short distance of the outfall diffuser and generally within 2m of the estuary bed. Further modelling continues in discussion with the Environment Agency.

Much of the sediment carried from the intake in the estuary water will settle out within the gas storage caverns during their creation. It is expected that the amount of sediment discharged through the outfall will be less than the amount abstracted. There will be no temperature or chemical contamination impacts associated with the saltwater returned to the Mersey Estuary.

Traffic and Transportation

The proposed pipeline route crosses two motorways: the M53 and M56. Both are crossed twice. The proposed pipeline route also crosses nine Class A roads, a total of eleven times. The proposed pipeline route crosses four Class B roads. All motorways, A roads and the B5133 (Hooton Road) will crossed by tunnelling and will not be disrupted. All other road crossings will be via open trench. In addition, the pipelines are currently proposed to be laid within the carriageways or verges of four roads, most notably a short section of the A41, New Chester Road, at Eastham.

Railway lines will be crossed a total of eight times, however, all will crossed by tunnelling techniques and will not be disrupted.

The main impacts on the local road network will occur during the construction phase of the pipeline and will result from:

• Temporary increases in existing traffic flows due to construction traffic including delivery vehicles, potentially leading to congestion and delay to other road users; and

• Temporary disruption to the existing road network where the pipeline crosses or is within roads, due the physical construction of the pipelines.

Temporary increases in existing traffic flows, resulting from construction traffic, will be, at worst, very slight. This is because of the relatively small numbers of construction vehicles used and their spread along the entire length of the pipeline route. These impacts will largely be confined to key areas of construction, such as the temporary site compounds and storage areas, the pumping station construction sites, and the sections of the roads designated as accesses to/from the working corridor.

Disruption impacts to the users of the existing road network, due to open trench construction of the pipelines will have minor adverse impacts with the implementation of traffic control measures. However, all impacts will be of a temporary nature and will be highly localised.

Socio-Economics, Tourism and Community Effects

The proposed pipeline route crosses, or is within a distance of 50m of 45 Public Rights of Way within Cheshire, of which 35 are Footpaths, three are Bridleways and seven Restricted Byways, as defined by the Definitive Maps produced by Cheshire County Council. Within Wirral the proposed pipeline route affects three Public Rights of Way, including one designated public



Bridleway, with a further two Footpaths in close proximity. A total of six long distance trails and promoted walks are crossed.

No Access Land within Cheshire or the Wirral is affected.

Recreational pursuits within 500m of the pipeline route include fishing, horse-riding, golf courses, sports and playing fields, and country parks. Other community facilities include a college, allotment gardens a youth centre, a hospice, a primary school, and two nature reserves.

The construction phase of the pipeline works may result in adverse impacts on a variety of community, social and economic activities in the area. These will be temporary and highly localised. They include impacts to the amenity and enjoyment of recreational, sports and community facilities and visitor attractions, and impacts to Public Rights of Way, other recreational routes and country pursuits. With the implementation of mitigation measures, the majority of these impacts are considered of negligible to minor adverse significance.

More significant impacts are those to Public Rights of Ways, including the Delamere Way and the North Cheshire Way, particularly those which will require temporary closures and diversions to be put in place. These footpaths will be kept open as long as possible, with stiles, gates and directional signs provided to facilitate safe public access across the working width. On completion, all Public Rights of Ways will be reinstated to their original alignment and condition.

The most significant socio-economic impacts are anticipated to occur with regard to Eastham Lodge Golf Course, the sports and playing fields associated with Leverhulme Sports Ground and Eastham Village recreation ground, all of which are crossed by the proposed route alignment. With these locations every effort has been made to position the pipeline such that minimal disruption, disturbance and amenity impacts arise. Discussions will continue throughout the detailed design and construction phases, with relevant owners and operators, to further reduce impacts wherever possible.

Emissions to Land and Air

The construction phase of the proposed pipelines has the potential to result in emissions to land and air environments in the form of mud, spillages of fuels, oils and hazardous substances, sewage and waste water, solid wastes, noise, dust, exhaust emissions, and light.

It is proposed that the above described emissions will be managed and controlled during the construction phase through the implementation of the CEMP, and a Site Waste Management Plan (which will form part of the CEMP).

The Applicant will make every effort to keep the generation of dust to a minimum, with the implementation of construction best practice techniques. Mitigation measures to prevent transferring mud from the working corridor to local roads will be implemented by the Applicant, including measures such as wheel washers and road sweepers.

General wastes from the temporary site compounds will be segregated and recycled; excavated material from the pipeline trench will be reused for backfilling, wherever possible; and where practicable, all organic material removed as part of the site clearance works will be chipped and re-used as mulch during reinstatement. All waste management will undertaken in accordance with Waste Management: The Duty of Care - Code of Practice, 1996 and the Hazardous Waste Regulations, 2005.



Noise generated from the construction phase may temporarily affect people living or working close by, particularly those located within 100m of the pipeline working width. This will be unavoidable in built up areas, however, in the rural areas through which the majority of the route passes, the settlements and properties are largely avoided. Construction of special sections, such as road and river crossings, may create increased noise levels over a slightly longer duration, but will also be of a temporary nature and highly localised.

In order to minimise all noise impacts, good construction environmental best practice mitigation measures will be implemented, such as best practicable means, as defined in Section 72 of the Control of Pollution Act 1974, in agreement Cheshire County Council and/or Wirral MBC.

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