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TRANSPORT AND WORKS ACT 1992
Transport and Works (Applications and Objections
Procedure) (England and Wales) Rules 2006
THE NETWORK RAIL
(EAST WEST RAIL WESTERN SECTION PHASE 2) ORDER
DRAFT ENVIRONMENTAL STATEMENT
CHAPTER 11: GEOLOGY, SOILS AND LAND CONTAMINATION
Document Reference 133735-PBR-REP-EEN-
000009
Author Network Rail
Date June 2017
Date of revision and revision
number
June 2017
2.0
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
CONTENTS
11. GEOLOGY, SOILS AND LAND CONTAMINATION ......................................... 1
11.1 Introduction ........................................................................................................ 1
11.2 Limitations and Assumptions ............................................................................. 2
11.3 Legislation, Policy and Guidance ....................................................................... 5
11.4 Approach and Methodology ............................................................................. 14
11.5 Baseline Conditions ......................................................................................... 25
11.6 Assessment of Effects ..................................................................................... 59
11.7 Mitigation ....................................................................................................... 136
11.8 Residual Effects ............................................................................................. 137
LIST OF TABLES
Table 11.1 Local Planning Policies and Mineral Plans ............................................... 9
Table 11.2 Scoping Report Responses .................................................................... 16
Table 11.3 Estimation of the level of risk by comparison of consequence and probability ................................................................................................................. 19
Table 11.4 Defining the Sensitivity of Receptors ...................................................... 20
Table 11.5 Classification of Effects: Geology as a Resource (a) .............................. 21
Table 11.6 Significance Criteria: Physical Effects of the Project (b) ......................... 22
Table 11.7 Significance Criteria: Land Contamination Risk and Part 2A Status (c) . 23
Table 11.8 Significance criteria: waste soils and material re-use (e) ........................ 24
Table 11.9 Summary of Encountered Ground Conditions: Claydon Junction to Jarvis Lane, Bicester .......................................................................................................... 26
Table 11.10 Summary of Encountered Ground Conditions: Claydon Junction to Bletchley ................................................................................................................... 28
Table 11.11 Summary of Encountered Ground Conditions: Claydon Junction to Aylesbury ................................................................................................................. 29
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Table 11.12 Summary of Potential Mineral Resources from Mineral Safeguarding Plans ........................................................................................................................ 30
Table 11.13 Summary of Geological Hazards by Project Sub-section ..................... 32
Table 11.14 Summary of Controlled Waters Receptors by Sub-section .................. 34
Table 11.15 Summary of Designated Ecological Sites by Sub-section .................... 38
Table 11.16 Off-Site Human Health Receptors ........................................................ 41
Table 11.17 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Cherwell District Council sub-section ........................................ 44
Table 11.18 Baseline Phase Conceptual Site Model Findings: Potential Contaminant Linkages within the Aylesbury Vale: Claydon/Quainton sub-section ........................ 45
Table 11.19 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Aylesbury Vale: Winslow/Swanbourne sub-section. ................. 47
Table 11.20 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Aylesbury Vale: Aylesbury sub-section ..................................... 49
Table 11.21 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Wycombe District Council sub-section. ..................................... 51
Table 11.22 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Milton Keynes Council sub-section ........................................... 53
Table 11.23 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Central Bedfordshire Council sub-section. ................................ 55
Table 11.24 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Bedford Borough Council sub-section ....................................... 57
Table 11.25 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Cherwell District Council sub-section .................................................................................................. 61
Table 11.26 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Claydon/Quainton sub-section ................................................................................. 63
Table 11.27 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Winslow/Swanbourne sub-section............................................................................ 65
Table 11.28 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Aylesbury sub-section .............................................................................................. 67
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Table 11.29 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Wycombe District Council sub-section .................................................................................................. 69
Table 11.30 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Milton Keynes Council sub-section ............................................................................................................... 71
Table 11.31 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Central Bedfordshire Council sub-section .................................................................................................. 73
Table 11.32 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Bedford Borough Council sub-section .................................................................................................. 75
Table 11.33 Construction Phase Land Contamination Impact Assessment for the Cherwell District Council sub-section ....................................................................... 78
Table 11.34 Construction Phase Impact Assessment for the Aylesbury Vale: Claydon/Quainton sub-section ................................................................................. 80
Table 11.35 Construction Phase Impact Assessment for the Aylesbury Vale: Winslow/Swanbourne sub-section............................................................................ 83
Table 11.36 Construction Phase Impact Assessment for the Aylesbury Vale: Aylesbury sub-section .............................................................................................. 86
Table 11.37 Construction Phase Impact Assessment for the Wycombe District Council sub-section .................................................................................................. 89
Table 11.38 Construction Phase Impact Assessment for the Milton Keynes Council sub-section ............................................................................................................... 92
Table 11.39 Construction Phase Impact Assessment for the Central Bedfordshire Council sub-section .................................................................................................. 95
Table 11.40 Construction Phase Impact Assessment for the Bedford Borough Council sub-section .................................................................................................. 98
Table 11.41 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Cherwell District Council sub-section ................................................................................................ 103
Table 11.42 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Claydon/Quainton sub-section ............................................................................... 105
Table 11.43 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Winslow/Swanbourne sub-section.......................................................................... 107
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Table 11.44 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Aylesbury sub-section ............................................................................................ 109
Table 11.45 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Wycombe District Council sub-section ................................................................................................ 111
Table 11.46 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Milton Keynes Council sub-section ............................................................................................................. 113
Table 11.47 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Central Bedfordshire Council sub-section ................................................................................................ 115
Table 11.48 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Bedford Borough Council sub-section ................................................................................................ 117
Table 11.49 Operational Phase Impact Assessment for the Cherwell District Council sub-section ............................................................................................................. 121
Table 11.50 Operational Phase Impact Assessment for the Aylesbury Vale: Claydon/Quainton sub-section ............................................................................... 122
Table 11.51 Operational Phase Impact Assessment for the Aylesbury Vale: Winslow/Swanbourne sub-section.......................................................................... 124
Table 11.52 Operational Phase Impact Assessment for the Aylesbury Vale: Aylesbury sub-section ............................................................................................ 126
Table 11.53 Operational Phase Impact Assessment for the Wycombe District Council sub-section ................................................................................................ 128
Table 11.54 Operational Phase Impact Assessment for the Milton Keynes Council sub-section ............................................................................................................. 130
Table 11.55 Operational Phase Impact Assessment for the Central Bedfordshire Council sub-section ................................................................................................ 132
Table 11.56 Operational Phase Impact Assessment for the Bedford Borough Council sub-section ............................................................................................................. 134
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 1
11. GEOLOGY, SOILS AND LAND CONTAMINATION
Summary
Baseline
The Project Area is largely active railway surrounded by rural and residential land uses. A section of the Project is disused railway. There are a number of potential sources of contamination, including active and historic landfills within 500 m of the Project Area. Superficial Alluvial and River Terrace Deposits are localised Secondary A aquifers. A small portion of the Project overlies a Principal aquifer. Numerous surface water courses pass beneath the route. There are no significant areas of potential ground instability, and limited economic mineral resource potential.
Effects
The assessment found that with incorporated mitigation the ground conditions (including stability) and contamination effects are assessed as neutral and not significant.
Mitigation
No additional mitigation measures beyond those required under legislative and best practice have been identified.
Residual Effects
No residual effects are anticipated.
11.1 Introduction
11.1.1 This chapter of the Draft ES identifies and assesses the effect of the
Project on geology, soils and land contamination. The potential effects of
the Project on surface and groundwater, including flooding, are covered in
detail in Chapter 13 (Water Quality and Flood Risk).
11.1.2 The assessment of the geology, soil and land contamination effects of the
Project covers the shorter term effects during construction and the longer
term effects arising from the operation of the Project. The Department for
Communities and Local Government (DCLG) ‘Environmental Impact
Assessment: A guide to good practice and procedures’275 identifies the
following effects which may be relevant to the assessment of a
development on geology, soils and/or land contamination:
275
http://webarchive.nationalarchives.gov.uk/20120919132719/www.communities.gov.uk/documents/planningandbuilding/pdf/151087
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Draft Environmental Statement
Volume 2 Chapter 11 Page 2
(a) Effects of the Project on geology as a resource, e.g. loss of or damage to Local Geological Sites276, geological sites of special scientific interest (SSSIs) or mineral resource sterilisation;
(b) Physical effects of the Project, e.g. ground stability;
(c) The potential for existing ground contamination to be mobilised, the addition of pathways for migration and/or additional receptors, or effects associated with the potential for polluting substances used (during construction/operation) to cause new ground contamination issues on site, e.g. introducing/changing the source of contamination;
(d) Effects on land use/resources, e.g. quantity and quality of agricultural soils taken, effect on surrounding land uses, loss of greenfield land; and
(e) Impacts associated with re-use of soils and waste soils, e.g. re-use of site-sourced materials on-site or off-site, disposal of site-sourced materials or importation of materials to the site.
11.1.3 In order to assess the effects set out above, this chapter assesses the
effects of the Project on geology and mineral resources (a), physical
effects (b), the potential for contamination to be introduced to the
environment or mobilised as a result of the works (c), and effects
associated with the re-use of soils and waste soils (e). Some of these
effects may be managed through the incorporation of embedded
mitigation measures; this is discussed in Section 11.2.
11.1.4 The assessment of effects on soils in use for agricultural purposes (d) is
discussed within Chapter 6 (Land Use and Agriculture). The detail of
material importation/re-use is not covered in this chapter. Chapter 2
(Project Description) sets out more information about how the Project will
approach waste management.
11.2 Limitations and Assumptions
11.2.1 General limitations to assessments within the Draft ES are outlined in
Chapter 4 (EIA Methodology) Section 4.11. With regard to Geology, Soils
276 Government guidance uses the term Local Sites for non-statutory sites, as distinct from the Sites of Special Scientific Interest [SSSIs] which are protected by government statute. The term Regionally Important Geological/geomorphological Sites (RIGS) has been in usage now for many years and is still used to describe Local Geological and should be regarded as synonymous. (http://wiki.geoconservationuk.org.uk/index.php5?title=Main_Page).
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Draft Environmental Statement
Volume 2 Chapter 11 Page 3
and Land Contamination the following limitations were encountered during
the process of collating baseline information and undertaking the
subsequent assessment:
Intrusive investigation has been undertaken across the Project; however restrictions on third party land access have resulted incomplete coverage of the Project Area. The focus and design of the investigation was also geotechnical which has further limited the usefulness of the data gathered in relation to contamination; and
Groundwater gauging and sampling of the installed wells has yet to be undertaken.
11.2.2 In order to ensure a robust assessment, the following assumptions have
therefore been incorporated into the assessment of the Project:
Members of the public will have no direct access to the Project Area during construction works (thereby reducing the likelihood for human health exposure to potentially contaminated materials); and
Construction best practice will be adhered to at all times during the works.
11.2.3 It should be noted that the risk assessment and impact assessments have
been carried out predominantly using desk-based information, i.e. a
qualitative assessment. Though informative these assessments are
unavoidably high level. Risks such as the potential for ground gas
migration to impact the works and for groundwater receptors to be
impacted as a result of piling works proposed within the Project can only
be appropriately assessed by undertaking further targeted intrusive
ground investigation.
11.2.4 Groundwater gauging and sampling of the installed monitoring wells will
be undertaken in the vicinity of key areas of proposed earthworks.
Ground gas monitoring will also be carried out in key risk areas. Piling risk
assessments must also be undertaken in line with the requirements set
out within the desk study in order to fully characterise and mitigate the
risks to groundwater.
Embedded Mitigation
11.2.5 In relation to soils, geology and land contamination, measures considered
to be ‘construction best practice’ are integral to the Project’s construction.
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Draft Environmental Statement
Volume 2 Chapter 11 Page 4
The Code of Construction Practice (CoCP) for the Project will set out and
deliver the measures to be implemented during construction. A draft
CoCP is appended to this Draft ES. In relation to geology, soils and land
contamination, these measures will be:
Areas of contamination will be identified and remediated by specialist contractors prior to general construction access;
Construction workers will be provided with appropriate Personal Protective Equipment (PPE) and informed by risk assessment to limit their exposure to contamination;
Hand washing facilities will be made available to site operatives, site rules will be created insisting on hand washing prior to breaks and at the end of the working day, and eating and drinking will be limited to site welfare facilities during agreed break periods;
Provision of specific dust mitigation measures will be implemented;
The work area will be well delineated and kept secure to prevent trespass;
Silt mitigation measures will be implemented to limit runoff of exposed soil into watercourses. Bunds, cut-off ditches, settlement ponds and drainage covers will be utilised to limit runoff from entering watercourses;
Spill kits and plant nappies will be provided for all static plant and equipment;
Environmental awareness training will be provided and documented to all staff working on the Project, including daily site briefings (Toolbox Talks);
Re-fuelling will be via a mobile bowser (storage and supply tank)
equipped with a full spill kit and bunding. No refuelling will take place within 10 m of a water course or receptor;
A procedure will be included within the CoCP to manage previously-unidentified contaminated material that is encountered during the works;
Storage areas for materials will be identified, and surplus soil arisings from levelling or excavation works that demonstrate visual or olfactory evidence of contamination will be stored in covered skips, or on a sheeted stockpile placed on hardstanding or sheeting pending its removal or treatment; and
The intrusive investigation to characterise ground conditions will incorporate an assessment of the ground aggressivity which will inform the design of the Project. Further specific intrusive investigation will likely be required prior to the commencement of construction.
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Draft Environmental Statement
Volume 2 Chapter 11 Page 5
11.2.6 The assessment of likely significant effects during construction therefore
takes into account implementation of these mitigation measures. During
the operational phase further mitigation measures are embedded into the
design of the Project, such as an improvement of drainage infrastructure
and the removal/remediation of contaminated arisings encountered
following the construction phase.
11.3 Legislation, Policy and Guidance
11.3.1 National and local policy and guidance considered within this assessment
are detailed below. The list is not intended to be exhaustive, but includes
the main documents relating to the protection, preservation and, where
appropriate, enhancement of the geological environment.
Legislative Framework
11.3.2 The legislative framework applicable to this assessment is summarised as
follows:
Part 2A of the Environmental Protection Act 1990 (as amended)277;
the Environment Act 1995278;
The Control of Substances Hazardous to Human Health Regulations 2002 (as amended) (COSHH Regulations)279;
The Water Environment (Water Framework Directive) (England and Wales) Regulations 2003280;
Dangerous Substances Directive (Amendment) 2006281;
Environmental Damage and Liability (Prevention and Remediation) Regulations 2009282;
The Environmental Permitting (England and Wales) Regulations 2010283;
Environmental Permitting Regulations 2016284;
277 HMSO (1990) Part 2A of the Environmental Protection Act, 1990
278 HMSO (1995) Environment Act, 1995
279 SI 2002/2677 (as amended)
280 SI 2003/3242
281 SI 2006/3311
282 SI 2015/810
283 SI 2010/675 (as amended)
284 SI 2010/675 (as amended)
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 6
Waste Framework Directive 2008;
Waste (England and Wales) (Amendment) Regulations 2012;
Landfill Regulations285, which implement the requirements of the Landfill Directive (99/31/EC);
Hazardous Waste Regulations286;
Control of Asbestos Regulations 2012287;
Contaminated Land (England) (Amendment) Regulations 2012288; and
Construction (Design & Management) Regulations 2015 (CDM Regulations)289.
Land Quality and Contamination
11.3.3 Part 2A establishes a legal framework for dealing with land contamination
in the UK. It provides a means of dealing with unacceptable risks posed
by land contamination to human health and the environment. Government
objectives with respect to land contamination policy and the Part 2A
regime are set out in the Department for Environment Food and Rural
Affairs (Defra) Contaminated Land Statutory Guidance 2012290 as:
To identify and remove unacceptable risks to human health and the environment;
To seek to ensure that contaminated land is made suitable for its current use; and
To ensure that the burdens faced by individuals, companies and society as a whole are proportionate, manageable and compatible with the principles of sustainable development.
11.3.4 The Contaminated Land regime as set out in Part 2A of the Environmental
Protection Act 1990, secondary legislation291 and relevant guidance292,
does not address potential risks to construction or maintenance workers
or other occupations which may have direct exposure to contaminated
285 SI 2002/1559
286 SI 2005/894
287 SI 2012/632
288 SI 2012/263
289 SI 2015/51 290 Department for Environment Food and Rural Affairs. Environmental Protection Act 1990: Part 2A. Contaminated Land Statutory
Guidance. April 2012.
291 Contaminated Land (England) Regulations 2006 (SI 2006/1380) and Contaminated Land (Wales) Regulations 2006 (SI 2006/2989), which include details of grounds for appeal and when land should be designated as a special site, and Radioactive Contaminated Land (Modification of Enactments) (England) Regulations 2006 (SI 2006/1379).
292 Defra: Contaminated Land Statutory Guidance (April 2012).
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 7
land. The risks to these human receptors are managed through health
and safety legislation, such as the COSHH Regulations and the CDM
Regulations which require the employer to carry out an assessment of the
risks associated with exposure to hazardous substances and then to
prevent those risks, and, if this is not reasonably practicable, to
adequately control such exposures.
Waste Soils and Materials Re-use
11.3.5 The Waste Framework Directive 2008 (WFD 2008)293 establishes the
legislative framework for the management, recovery and disposal of
waste. It also provides a definition of waste as “any substance or object
which the holder discards or intends or is required to discard.”
11.3.6 The most recent revisions to the WFD 2008 are transposed in England
and Wales through the Waste (England and Wales) (Amendment)
Regulations 2012. Accordingly, where uncontaminated soils and other
natural materials (for example, rock) are excavated during earthworks and
it is proposed to re-use them in the construction of the Project, then these
materials would fall outside the definition of waste and so outside the
waste management regime.
11.3.7 The WFD 2008 specifically excludes from its scope “uncontaminated soil
and other naturally occurring material excavated in the course of
construction activities where it is certain that the material will be used for
the purposes of construction in its natural state on the site from which it
was excavated.”
11.3.8 Material that is surplus to requirements or needs to be discarded (e.g. due
to its engineering properties or contamination) is strictly classified as
waste and should be disposed of in accordance with waste duty of care
requirements, including the Landfill Regulations294, Hazardous Waste
Regulations295 and publication WM3296.
293 2008/98/EC
294 SI 2002/1559
295 SI 2005/894
296 Environment Agency (2015). Hazardous Waste Classification – Guidance on the classification and assessment of waste.
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11.3.9 Re-use of materials on site can be managed through either the
Environmental Permitting Regulations 2016297 (EPR) or in accordance with
the guidance provided in the Contaminated Land: Applications in Real
Environments (CL:AIRE) Code of Practice Definition of Waste: Code of
Practice (CoP)298.
11.3.10 Inert excavated material can be re-used without consent, providing that
the works for which it is used are part of the development design and
approved under planning consents. Under the CL:AIRE CoP, materials
excavated on-site are not deemed to be waste if it can be demonstrated
that they are suitable for re-use within the development, subject to the
relevant assessment, the preparation of a Materials Management Plan
and a declaration by a CL:AIRE Qualified Person.
National Planning Policy
National Planning Policy Framework (2012)
11.3.11 The National Planning Policy Framework (NPPF)299 sets out the
Government’s interpretation of the planning system and identifies main
policy objectives and principles. With regard to development of land, the
NPPF states that Local Planning Authorities should take into account the
nature, scale and extent of contamination which may pose risks to health,
the natural environment and the potential sensitivity of the area or
proposed development. In order to achieve these objectives the
Government aims for every local authority in England to draft and adopt a
local plan. The plans set out local planning objectives, policies and identify
how land is currently utilised. These plans are developed in consultation
with local communities and provide a framework by which proposed
developments are assessed by planning officers with regard to the
requirements of local populations/infrastructure. Local plans are therefore
compiled to ensure that when assessing developments:
297 SI 2010/675 (as amended)
298 CL:AIRE (2011) The Definition of Waste: Development Industry Code of Practice.
299 Department for Communities and Local Government (2012) National Planning Policy Framework
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The natural and local environment are protected and enhanced, including protection and enhancement of valued landscapes, geological interests and soils, remediating and mitigating despoiled, degraded, derelict, contaminated and unstable land (Paragraph 109);
To prevent unacceptable risks from pollution and land instability planning policies and decisions should ensure a development is appropriate for its location (Paragraph 120);
Sites are suitable for their proposed new use, taking account of ground conditions and land instability, including from natural hazards or former
activities. Once developed, the land should not be capable of being determined as Contaminated Land under Part 2A (Paragraph 121); and
11.3.12 Mineral resources should be protected from development through the
formulation of mineral safeguarding areas (Paragraphs 142 and 143).
Local Planning Policy
11.3.13 Local planning policies for the Project Area have been reviewed as part of
this assessment and are listed in Table 11.1. The local core mineral
strategies have also been reviewed identifying mineral safeguarding areas
adjacent to the Project Area.
Table 11.1 Local Planning Policies and Mineral Plans
Relevant Local Planning Policies/Mineral Strategies
Local Authority Sub-section
Adopted Cherwell Local Plan 2011 -
2031 (July 2015)
Cherwell District Council
The Oxford Minerals and Waste Core
Strategy (August 2015)
Adopted Aylesbury Vale District Local
Plan (January 2004)300 Aylesbury Vale: Claydon/ Quainton;
Winslow/Swanbourne and Aylesbury
Wycombe District Council (WDC) (subject
to Buckinghamshire Mineral strategy) The Buckinghamshire Minerals and
Waste Core Strategy (November 2012)
The Milton Keynes Local Plan (2005)301
The Milton Keynes Core Strategy
(2013)
Milton Keynes Council
300 The Vale of Aylesbury Local Plan is currently being reviewed following closure of the public consultation period in
September 2016.
301 The Milton Keynes Local Plan (referred to as Plan:MK) is under preparation at the time of writing following closure of the
consultation period in April 2016.
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Volume 2 Chapter 11 Page 10
Relevant Local Planning Policies/Mineral Strategies
Local Authority Sub-section
Milton Keynes Minerals Local Plan
2001 – 2011 Adopted (April 2006)302 Milton Keynes Council
The Central Bedfordshire Core
Strategy (2009 – 2026) (2009)
Central Bedfordshire Council,
Bedfordshire Borough Council Bedford Borough, Central
Bedfordshire and Luton Borough
Council Minerals and Waste Local Plan
(2014)
The Wycombe District Local Plan
(2004)303
The Wycombe Core Strategy (2008 –
2026)
Wycombe District Council
Adopted Cherwell Local Plan 2011-2031 (July 2015)
11.3.14 The Cherwell Local Plan states that the Cherwell District Council (CDC)
has a number of key challenges to ensuring sustainable development
such as “a need to ensure that contamination is addressed effectively on
sites through re-development”. Policy ESD10 states that during
development “the reuse of soils will be sought”. Policy ENV12
encourages development to occur on brownfield land.
The Oxford Minerals and Waste Core Strategy (2015)
11.3.15 Policy M9 requires that “mineral infrastructure that supports the supply of
minerals in Oxfordshire is safeguarded against development that would
unnecessarily prevent the operation of the infrastructure or would
prejudice or jeopardise its continued use by creating incompatible land
uses nearby.”
Adopted Aylesbury Vale District Local Plan (AVDLP) (2004)
11.3.16 In 2007 the policies contained within this plan ceased to be in effect
unless saved by a Direction from the Secretary of State. The new Vale of
Aylesbury Local Plan (VALP) has yet to be adopted. No policies relevant
to this assessment were saved from the AVDLP.
302 The updated Milton Keynes Minerals Local Plan was submitted to the Secretary of State for review in March 2016.
303 An updated Wycombe District Local Plan to cover the period up to 2033 is currently in preparation.
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The Buckinghamshire Minerals and Waste Core Strategy (2012)
11.3.17 Strategic Objective 03 of the Buckinghamshire Minerals and Waste Core
Strategy Development Plan is “to protect the county’s mineral resources
within the Thames Valley, where the richest deposits of sand and gravel
are to be found and potentially viable resources in north Buckinghamshire
from development which would prevent their future use.”
Adopted Milton Keynes Local Plan (2005)
11.3.18 Milton Keynes Council (MKC) is currently preparing a new local plan for
the Borough called Plan:MK, although it has yet to be finalised and
adopted. Only those policies saved from the Milton Keynes Local Plan are
currently adopted. The following policy relevant to this chapter has been
saved from the previous Local Plan; NE3 states that “all new development
should incorporate proposals to enhance geological features and where
possible compensate for impacts on the immediate area and site
characteristics.”
Milton Keynes Minerals Local Plan (April 2006)
11.3.19 Policy MLP4 states that the planning authority “will not permit
development proposals that would cause sterilisation of mineral deposits
on the proposed development site, or which prejudice the future working
of minerals on adjacent sites.”
11.3.20 There are three exceptions to this policy which are:
The mineral deposit is not currently commercially viable and is unlikely to be in future;
There is a case in favour for allowing the proposed development to proceed without prior extraction of the mineral; and
Extraction of the mineral would be subject to strong environmental or other objections making it highly unlikely to be permitted.
The Central Bedfordshire Core Strategy (2009)
11.3.21 Policy CS18 states that the council will:
“Support the designation, management, and protection of biodiversity and
geology including national designations (SSSIs), locally important County
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Wildlife Sites (CWSs) and Regionally Important Geological and
Geomorphological Sites (RIGGS304); as well as those local priority habitats
and species identified in the Local Biodiversity Action Plan.”
Bedford Borough, Central Bedfordshire Minerals and Waste Local Plan (2014)
11.3.22 The Plan states that most development proposed within a mineral
safeguarding area will be subject to Mineral Strategic Policies (MSP) 11
and 12. MSP 11 requires that a Mineral Resource Assessment be
undertaken by a suitably qualified professional, which establishes through
site specific geological survey data, the existence or otherwise of a
mineral resource of economic importance. MSP 12 outlines the
circumstances under which mineral extraction will be permitted.
The Wycombe Local Plan (2004)
11.3.23 Saved policy RT19 includes the following guidance in paragraph 12.61
“Development proposals must also take particular regard of the ground
conditions and its stability due to mineral extraction and landfill activities in
the area.”
Building Control
11.3.24 Any construction work resulting in the creation of a structure is subject to
Building Control under the Building Regulations (2010)305. Requirement
C1. (2) states:
“Reasonable precautions shall be taken to avoid danger to health and
safety caused by contaminants on or in the ground covered, or to be
covered by the building and any land associated with the building”.
11.3.25 Contamination in the ground has the potential to attack and weaken
building materials which may consequently lead to a breach of Part A of
these Regulations which relate to structural safety. The following
approach is proscribed to address ground contamination:
304 Regionally Important Geological Sites (RIGS) and Regionally Important Geological and Geomorphological Sites (RIGGS)
are synonymous
305 HM Government (2010) The Building Regulations: Site preparation and resistance to contaminants and moisture C.
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Site investigation should be carried out to determine the extent and nature of any contamination;
Any ground covered by a building must be free from any material that might damage the building or affect its stability;
Reasonable precautions must be taken to avoid danger to health and safety caused by contaminants on or in the ground covered by a building or any land associated with that building; and
Precautions must be taken against ground gases such as landfill gases, radon, vapours etc.
Additional Guidance
11.3.26 The following additional guidance documents relevant to geology and
soils, and contaminated land have been considered when undertaking this
chapter:
The Design Manual for Roads and Bridges (DMRB) was utilised, which is a guidance document produced by Highways England (Volume 11, Section 2, Part 5 Assessment and Management of Environmental Effects, August 2008);
DMRB Volume 11, Section 3, Part 11 Geology and Soils, June 1993;
Contaminated Land Report (CLR) 11: Model Procedures for the Management of Land Contamination, produced jointly by the Environment Agency and Defra 2004;
Department of the Environment (DoE) – Industry Profiles for previously developed land, Environment Agency, 1995;
Construction Industry Research and Information Association (CIRIA) C552 – Contaminated Land Risk Assessment – A Guide to Good Practice 2001;
CIRIA C665 – Assessing Risks Posed by Hazardous Ground Gases to Buildings,2007;
CIRIA C681 – Unexploded Ordnance (UXO) – A Guide for the Construction Industry, 2009;
CIRIA C733 - Asbestos in Soil and Made Ground: A Guide to Understanding and Managing Risks, 2014;
CIRIA C682 – The Volatile Organic Contaminants (VOCs) Handbook, 2009;
Environmental Impact Assessment: A guide to good practice and procedures, Department for Communities and Local Government, June 2006; and
British Standards (BS) 10175:2011 (A1:2013) – Code of Practice for Investigation of Potentially Contaminated Sites.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 14
11.4 Approach and Methodology
11.4.1 The approach to the assessment comprises:
Establishing the baseline conditions for the area of study with respect of, but no limited to geology, mineral resources, regionally important geology sites (RIGs), ground stability, soils, hydrology, hydrogeology, contaminated land (including the potential for unexploded ordnance and ground gases) and historical uses supplemented in some areas by intrusive investigation;
Identification of potential impacts on identified resources and receptors, such as local geological sites, from the construction and operational phases;
Assessment of the significance of likely effects from the Project;
Identification of potential measures for mitigating any likely significant effects resulting from the Project; and
Identification of any residual effects.
Establishing the Baseline
11.4.2 The baseline has relied on existing data, reports, and historic records.
The following sources have been reviewed:
Environmental data from Landmark Envirocheck report (April 2015);
Historical mapping at scales of 1:10,000 and 1:2,500 from publically-available mapping sources to identify former industrial or similar land uses with the potential to cause residual land contamination or indicate possible ground stability issues, or areas of geological significance such as a mineral resources which could at some point be subject to extraction, or features which demonstrate an educational value;
Local Authority mineral plans, which set out the planning framework for future mineral extraction and associated development were used to identify ‘mineral safeguarding areas’ which could potentially be affected by the Project;
Local geology groups were contacted to identify regionally important geological sites (RIGs) also known as local geology sites which are sites designated for their importance in terms of geology or geomorphology. They are not afforded the statutory management protection enjoyed by SSSIs;
Existing risk assessment reports regarding the potential risk from unexploded ordnance;
Preliminary consultation advice from the Environment Agency, local authorities and other regulatory agencies from the Scoping Opinion responses in respect of potential impacts to ground conditions; and
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 15
A series of ground investigation reports have been consulted in order to obtain high-level ground conditions information such as geological succession and the presence/absence of significant thicknesses of Made Ground306.
11.4.3 During operation, HS2 is considered part of the Operational Baseline, so
has not been considered cumulatively.
Spatial Scope
11.4.4 The definition of the study area takes into account the transport and final
location of potential contaminants of concern in the environment, and the
connectivity of these contaminants via pathways of migration/exposure to
the receptors identified. A 500 m zone from the site boundary is
commonly used for the initial consideration of potential land contamination
and associated potential risks for schemes such as this, where
contamination is generally historic and likely to be of limited lateral
mobility307. If the presence of mobile contaminants and migration
pathways is confirmed, then the area subject of study may be extended to
identify additional receptors. Based on the land quality baseline
information compiled for the Scoping Report, the extension of the area
subject of study beyond 500 m from the Project Boundary was not
considered necessary. The Project drawings show a 250 m buffer zone
from the Project Boundary, which is the most critical area for identification
of potential sensitive receptors and sources of risk such as contamination
or areas of ground instability.
11.4.5 The only exception to this buffer zone was when considering ecological
receptors. A maximum 1 km lateral ‘buffer’ zone was selected from the
Project Boundary in this instance to incorporate the risks of ecological
receptors travelling beyond identified habitats.
306 Made Ground is described by the BGS as “artificial ground, often previously developed, associated with potentially
contaminated material, unpredictable engineering conditions and unstable ground”.
307 During the Scoping stage, baseline information was reviewed in order to confirm potential contamination sources and
sensitive receptors, and 500 m was judged to be sufficient to capture potential effects given the particular environment setting of the Project.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 16
Temporal Scope
11.4.6 The assessment considered the potential impacts and associated
significance of effects at the following stages:
The construction phase (2019); and
The operational phase (2024).
Consultation
11.4.7 Following issue of the Scoping Report, feedback was received from
stakeholders with regard to the scope of the assessment. These are
detailed in Table 11.2, alongside a response to each comment. Where
respondents made duplicate comments these are included once in the
table.
Table 11.2 Scoping Report Responses
Consultee Consultee comment Technical team response
Department for
Transport (DfT)
Groundwater and surface water
monitoring of Project requested
– including hydrocarbon testing
Groundwater gauging and
sampling not yet undertaken for
Project – additional intrusive
ground investigation is planned,
and this will be included as part
of that scope, in line with the
Compliance Assurance Quality
requirements under the Landfill
Directive.
EWR
Consortium Local geological sites should be
included as sensitive receptors
Local Geology Groups were
contacted to determine if any
such sites were in the vicinity of
the Project
Environment
Agency
Requested a detailed
investigation of each historic
and active landfill
The ground investigation scope
was confined to the Project
Area.
Requested consultation and
input into proposed drilling
methods to avoid creation of
preferential pathways for
contaminant migration
This will be addressed in
subsequent phases of intrusive
investigation, to be undertaken
in consultation with regards to
the GI design.
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Consultee Consultee comment Technical team response
Environment
Agency
Concern about impacts on
existing landfills at Stewartby
and Bletchley regarding
potential impacts to leachate
and gas management systems.
Letter drafted to landfill
operators and a meeting
undertaken with Environment
Agency - additional
consultation/risk assessment
required when works to be
undertaken on or in vicinity of
landfilled material and to define
the GI design.
11.4.8 To collect data relevant to the assessment, local authority members of the
EWR Consortium were consulted via email on 3 September 2015.
Responses were received from Wycombe District Council (WDC),
Aylesbury Vale District Council (AVDC) and Bedford Borough Council
(BBC). WDC and AVDC provided site investigation reports. BBC noted
that they held no relevant information.
11.4.9 Regular meetings with the Environment Agency have taken place to
discuss relevant issued posed by the Project. A meeting was held at the
Environment Agency Wallingford office on 8 December 2015 at which
they requested that their investigated site data was included in the
baseline. A shape file for mapping was provided which was reviewed,
however no detailed information was included. A factual summary of
Environment Agency investigated sites in the vicinity of the Project Area
has been included within the desk studies, which can be found in
Appendix (11.1).
11.4.10 The operators of landfills in the immediate vicinity of the Project were
consulted via letter in order to obtain background information on ground
conditions adjacent to the Project. No response was received from any of
these operators prior to the preparation of this Draft ES.
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Draft Environmental Statement
Volume 2 Chapter 11 Page 18
Methods
11.4.11 The method of assessing the potential impacts of the Project on geology,
soils and land contamination were carried out in two stages.
Stage 1: Risk Assessment
11.4.12 The approach for the risk assessment was based on Environment Agency
guidance document CLR11308 and the DCLG guidance on EIA. These
documents provide a technical framework for the application of a risk
management process through the following steps:
Preliminary Conceptual Site Model (PCSM): A desk study review of available information, including existing ground investigation data within the area of study, was undertaken to complete a PCSM, identifying potential hazards/sources, migration or exposure pathways and receptors relevant to the area subject of study, as well as potential geo-environmental hazards. A Conceptual Site Model (CSM) will be developed once further GI has been completed at the detailed design stage, when more site-specific information is available and the PCSM can be updated.
Risk assessment: A qualitative risk assessment has been carried out and is presented within this ES chapter using desk-based information only, on the basis of the PCSM. Where risks are identified, these will be appropriately mitigated through design and/or the development of a remediation strategy and its subsequent validation as necessary. The residual risks are determined and assessed based on the likelihood and consequence of their realisation. Once further GI data is available, generic quantitative risk assessments (GQRA) for human health and controlled water receptors will be undertaken.
11.4.13 The risk assessment used a methodology based on guidance provided in
CLR11308 and R&D66309 which provides direction on the development and
application of the consequence and probability matrix (see Table 11.3) for
contaminated land risk assessment.
308 Environment Agency. 2004. Model Procedures for the Management of Land Contamination. CLR11.
309 NHBC & Environment Agency. R&D 66
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Draft Environmental Statement
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Table 11.3 Estimation of the level of risk by comparison of consequence and
probability
Consequence
Severe Medium Mild Minor P
rob
ab
ilit
y
(Lik
elih
oo
d)
High
Likelihood Very high risk High risk Moderate risk Moderate /
low risk
Likely High risk Moderate risk
Moderate /
low risk Low risk
Low
Likelihood Moderate risk Moderate /
low risk Low risk Very low risk
Unlikely Moderate /
low risk Low risk Very low risk Very low risk
11.4.14 Definitions of probability, consequence and the classified risks (as given in
R&D66) adopted for this assessment are provided in Appendix 11.2.
Stage 2: Impact Assessment
11.4.15 The impact assessment was completed by comparison of the baseline
condition to both the construction and operational phase risk assessments
of the Project to determine the change in risk profile. The impact
assessment included those mitigation measures considered to be
embedded. The changes in contamination status are described as
positive, neutral or negative, and consideration is made of whether they
are major, moderate or minor (on the basis of the area over which the
effect may occur), duration (short, medium or long term) and whether the
effect is permanent or temporary. Appendix 11.2 presents an explanation
of these criteria.
11.4.16 In addition to the above, a value has been assigned to each of the
receptors with respect to its value and/or sensitivity. The definition of
each of these is given in Table 11.4. The value of a receptor is
considered when determining consequence or an effect in the risk
assessment.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
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Table 11.4 Defining the Sensitivity of Receptors
Value Criteria Examples
Very high
Very high importance / rarity;
international significance and very
limited opportunity for replacement.
Principal aquifer providing
potable supply to a large
population, within a
groundwater Source
Protection Zone (SPZ) 1. SPZ
are buffer zones defined by
the Environment Agency to be
protective for identified
groundwater sources such as
wells or boreholes.
Water Framework Directive
(WFD) high status surface
water body providing potable
supply to a small population.
Sensitive human health
receptors, e.g. young children.
Sterilisation or loss of
strategically-important mineral
resources.
Creation of ground instability
(on- or off-site)
Loss of potential for materials
re-use
High High importance and rarity; limited
opportunity for substitution.
Principal aquifer beyond a
SPZ, or a Secondary aquifer.
WFD good status surface
water body which implies that
the water body possesses a
good biological quality (a
diverse composition of
invertebrates), a good
hydromorphological quality -
measured elements include
river continuity, channel
patterns, and a good physico-
chemical quality- measured
elements include pH,
oxygenation, temperature and
concentrations of specific
pollutants. Surface waters can
be classified as good,
moderate, poor and bad
based upon an assessment of
these characteristics.
Less sensitive human
receptors, e.g. construction
workers using PPE.
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Draft Environmental Statement
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Value Criteria Examples
Loss of a significant proportion
of a regionally-important
mineral resource.
Creation of ground instability
(on-site structures affected)
Reduced potential for
materials re-use.
Medium
High or medium importance and
rarity, regional scale, limited
opportunity for substitution.
Secondary aquifer providing
abstraction of water for
agricultural or industrial use.
WFD moderate status.
A moderately economically
viable mineral resource.
Creation of ground instability
Minimal potential for materials
re-use.
Low Low or medium importance and
rarity, local scale.
Unproductive strata
(groundwater) are rock layers
of a low permeability which do
not contribute significantly to
river base flow or water
supplies.
WFD poor status.
No economically viable
minerals.
No changes to ground
stability.
No opportunity for material re-
use.
11.4.17 The classification of effects has been based on the criteria defined in
Table 11.7, and Table 11.5.
Table 11.5 Classification of Effects: Geology as a Resource (a)
Classification Effect
Major adverse
Loss of or major damage to a site designated due to its geological
attributes such as an SSSI including land take/ destruction of
distinctive geological features. Significant sterilisation of mineral
resources from an identified mineral safeguarding area such that it
is unavailable for development by future generations.
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Draft Environmental Statement
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Classification Effect
Moderate
adverse
Moderate damage to the amenity of a site designated due to its
geological attributes such as an SSSI. Moderate sterilisation of a
mineral resource from identified mineral safeguarding area.
Moderate damage to local geology sites and RIGs.
Minor adverse
Minor damage to the amenity of a site designated due to its
geological attributes such as an SSSI. Minor sterilisation of a
mineral resource from identified mineral safeguarding area. Minor
physical damage to Local Geological Sites.
Neutral No change to geological receptors identified during the baseline
as a result of the Project.
Minor beneficial
Slight improvement to a site designated due to its geological
attributes such as an improvement in access. An improvement of
access to a mineral safeguarding area (potentially facilitating
future mineral extraction) or a minor improvement in access to a
Local Geological site.
Moderate
beneficial
A moderate improvement to a site designated due to its geological
attributes such as an improvement in access. A moderate
improvement in access to Local Geological Sites as an education
resource and a moderate improvement in access to mineral
safeguarding areas (potentially facilitation future mineral
extraction).
Major beneficial
A major improvement to a site designated due to its geological
attributes such as SSSI; including improvements in access or
physical improvements to the site layout/surrounding
infrastructure. An improvement in access to identified mineral
safeguarding areas (potentially facilitating mineral extraction).
11.4.18 Table 11.6 presents an explanation of the significance criteria utilised in
terms of physical effects of the Project on soils and geology.
Table 11.6 Significance Criteria: Physical Effects of the Project (b)
Classification Effect
Major adverse
An increase in the risk of ground stability/soil compaction/erosion
issues from the existing baseline conditions from land which is
structurally stable in the baseline becomes a high or very high
risk. Land that is structurally stable in the existing baseline
becomes capable of landslide, building structural collapse, severe
erosion or severe compaction.
Moderate
adverse
An increase in the risk of ground stability/soil compaction/erosion
issues from the existing baseline becomes a moderate or high
risk. Land that is currently stable / competent in the existing
baseline becomes capable of building subsidence, moderate
erosion or moderate compaction.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
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Classification Effect
Minor adverse
An increase in ground stability risks from the existing baseline
conditions; land that has a low structural stability risk in the
baseline becomes moderate/low risk.
Neutral No change in land topography, soil compaction, soil erosion,
ground stability.
Minor beneficial
A minor improvement to the physical condition of the Project from
the existing baseline conditions, for example land that has a
moderate/low landslide risk in the baseline becomes a low risk.
Moderate
beneficial
A moderate improvement to the physical conditions of the Project
from the existing baseline conditions; for example land that
previously was unused as a result of its physical condition at
baseline is improved such that it comes back into use. For
example earthworks undertaken on railway embankments to
facilitate construction.
Major beneficial
An improvement to the physical condition of the Project from the
existing baseline conditions; for example land that has a very high
risk of landslide or significant erosion in the baseline becomes a
low or very low risk; such that the land is brought back into use.
11.4.19 Table 11.7 presents an explanation of the significance criteria utilised in
terms of ground contamination for the Project.
Table 11.7 Significance Criteria: Land Contamination Risk and Part 2A Status (c)
Classification Effect
Major adverse
An increase in contamination risk from the existing baseline
conditions from land that has a very low contamination risk in the
baseline becomes a high or very high risk. Land that does not
meet the statutory definition of Contaminated Land in the existing
baseline becomes capable of being determined under Part 2A.
Moderate
adverse
An increase in contamination risk from the existing baseline
conditions of land which has a low contamination risk in the
baseline becomes a moderate or high risk. Land that does not
meet the statutory definition of Contaminated Land in the existing
baseline becomes capable of being determined under Part 2A.
Minor adverse
An increase in contamination risk from the existing baseline
conditions; land that has a low contamination risk in the baseline
becomes moderate/low risk.
Neutral No change in contaminated land risks.
Minor beneficial
A reduction in contamination risk from the existing baseline
conditions, for example land that has a moderate/low
contamination risk in the baseline becomes a low risk.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
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Classification Effect
Moderate
beneficial
A reduction in contamination risk from the existing baseline
conditions; for example land that previously met the statutory
definition of Contaminated Land in the baseline is no longer
capable of being determined as Contaminated Land under Part
2A.
Major beneficial
A reduction in contamination risk from the existing baseline
conditions; for example land that has a very high contamination
risk in the baseline becomes a low or very low risk. Land that
previously met the statutory definition of Contaminated Land in the
baseline is no longer capable of being determined as
Contaminated Land under Part 2A.
11.4.20 Table 11.8 presents the significance criteria utilised during the waste soils
and materials re-use assessment.
Table 11.8 Significance criteria: waste soils and material re-use (e)
Classification Effect
Major adverse The generation of significant volumes of hazardous waste
requiring off-site disposal to appropriate landfill.
Moderate
adverse
The generation of a moderate volume of waste requiring offsite
disposal.
Minor adverse The generation of a minor amount of waste.
Neutral No waste generation as part of the Project, materials used
sustainably.
Minor beneficial A minor amount of materials reuse as part of the Project limiting
the offsite disposal of waste.
Moderate
beneficial
A moderate amount of materials reuse as part of the Project
limiting the offsite disposal of waste.
Major beneficial Sustainable use of material including recycling/reusing on site
material. No offsite disposal of wastes to landfill.
11.4.21 An effect that is moderate or major is considered to be a significant effect
in EIA terms for the purposes of this Draft ES. Minor and neutral effects
are not considered to be significant, in accordance with standard EIA
practice.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 25
11.5 Baseline Conditions
11.5.1 Data was collected to establish the baseline geological, hydrogeological,
hydrological and historical conditions through desk study review. The
following sections summarise the key environmental baseline conditions
for the Project, presented from west to east (and south to north for the
Aylesbury branch); additional information is given in the following figures:
Figures 11.1 to 11.8 – Superficial Geology
Figure 11.9 to 11.16 – Solid Geology
Figures 11.17 to 11.24 – Superficial Aquifer Designation
Figures 11.25 to 11.32 – Bedrock Aquifer Classification
Figures 11.73 to 11.80 – BGS Recorded Groundwater Wells
Figures 11.49 to 11.56 – BGS Recorded Mineral Sites
Figures 11.41 to 11.48 – Active Landfills
Figures 11.33 to 11.40 – Historic Landfills
Figures 13.1-13.8 - Water Constraints Maps
11.5.2 It is anticipated that Made Ground will be present along the length of the
Project, primarily associated with the original construction (and in places
removal) of the existing railway, as well as at specific locations where
landfilling or other earthworks have occurred. BGS geological mapping310
indicates that superficial deposits are likely to be present under discrete
sections of the railway, most notably along the eastern end and
associated with surface water courses. Localised superficial deposits
predominantly comprising till and alluvium are anticipated, as well as
windblown (Head) deposits of clay, silt, sand and gravel.
11.5.3 BGS mapping shows the Project to be underlain by the Oxford Clay
Formation, consisting of mudstones from the West Walton Formation,
Weymouth Member, Stewartby Member, and the Peterborough Member.
The Kellaways Formation is also anticipated. No structural features such
as fault lines are indicated to cross the Project Area. More detailed
geological information is provided in the Scoping Report (a copy of this
310 BGS website http://mapapps2.bgs.ac.uk/geoindex/home.html. Accessed September 2016.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 26
can be found in Appendix 1.1); site-specific information obtained from the
ground investigation is summarised below.
11.5.4 Where present, the superficial deposits are classified by the Environment
Agency as being either Secondary A or Secondary (undifferentiated)
aquifers. The mudstones of the Oxford Clay Formation are not water-
bearing strata and are therefore not classified as an aquifer. Where
present, the Kellaways Sand Member is classified, by the BGS mapping,
as a Secondary A aquifer.
11.5.5 The following tables summarise superficial deposits and bedrock
encountered during the intrusive ground investigation, as well as aquifer
classification (where applicable). It should be noted that the geographical
descriptors in this section do not currently correspond with the reporting
sub-sections used in the rest of this Draft ES. The final ES will address
this.
Table 11.9 Summary of Encountered Ground Conditions: Claydon Junction to
Jarvis Lane, Bicester
Superficial/Bedrock
Stratum and General Description
Maximum Reported Thickness
Aquifer Classification
Topsoil – Broadly
cohesive with sand
and gravel
components.
<0.50 m --
Made Ground – Re-
worked deposits of
cohesive and granular
material with varying
clay, sand and gravel
components.
Up to 5 m in railway
footprint of high
embankment,
generally 0.5-2 m
--
Superficial
Alluvium – Silt, Sand
and Gravel. Local
environment
previously dominated
by rivers.
4 m Secondary A
Glacial Deposits –
Cohesive. Soft to firm
bluish grey silty clays
with up to cobble
sized fragments of
chalk and rare bands
of sand.
2 m Secondary
(undifferentiated)
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Superficial/Bedrock
Stratum and General Description
Maximum Reported Thickness
Aquifer Classification
Bedrock
Oxford Clay –
Weymouth Member –
Firm becoming very
stiff pale grey
calcareous
mudstone/clay.
20 m Unproductive Strata
Oxford Clay –
Stewartby Member –
Firm becoming very
stiff pale to medium
grey smooth silicate
mudstone/clay with
subordinate beds of
shell debris.
20 m
Oxford Clay –
Peterborough Member
– Firm to very stiff
organic-rich brownish-
grey silicate
mudstone/clay.
25 m
Kellaways Sand
Member – Grey,
calcareous very silty
fine sand / sandy silt.
2 m to 5 m Secondary A
Kellaways Clay
Member – Firm to stiff
grey clay.
1 m to 4 m Unproductive Strata
Cornbrash Limestone
- Limestone, medium-
to fine-grained,
predominantly
bioclastic wackestone;
characteristically
bioturbated and poorly
bedded. Bluish grey
when fresh, but
weathers to olive or
yellowish brown. Thin
argillaceous partings
or interbeds of
calcareous mudstone
may occur.
1 m to 4 m Principal
Forest Marble –
Sillicate- mudstone,
greenish grey,
variably calcareous.
2 m to 7 m Secondary A
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Table 11.10 Summary of Encountered Ground Conditions: Claydon Junction to
Bletchley
Superficial/Bedrock
Stratum and General Description
Maximum Thickness
Aquifer Classification
Topsoil – Broadly cohesive with
sand and gravel components.
<0.5 m --
Made Ground – Re-worked
deposits of cohesive and granular
material with varying clay, sand
and gravel components.
Up to 8 m in
railway footprint
in areas of high
embankment.
Generally
between 0.5
and 2 m.
--
Relic Topsoil – Soft grey to black
organic clay. Organic material is
black amorphous peat.
<0.5 m --
Superficial
Alluvium – Silt, Sand and Gravel.
Local environment previously
dominated by rivers.
2 m Secondary A
River Terrace – Slightly sandy
medium to coarse gravel
deposits.
5 m
Head – Firm sandy gravelly
(stony) clays.
3 m Secondary
(undifferentiated)
Glacial Till – Firm becoming very
stiff sandy gravelly clay with
chalk, flint and mudstone gravel
and occasional cobbles.
30 m Unproductive
Strata
Glacial Deposits
(cohesive/granular) –
Undifferentiated Glacial Deposits
Broadly comprising interbedded
soft to firm occasionally silty,
sandy gravelly clay with
lenses/beds of sand and fine
gravel.
10 m Secondary
(undifferentiated)
Glaciofluvial Deposits – Generally
comprising sand and gravel
deposits of variable thickness
were also encountered.
10 m Secondary A
Bedrock
West Walton Formation – Firm
becoming very stiff dark grey silty
clay with interbedded pale grey
mudstone.
10-15 m Unproductive
Strata
Oxford Clay – Weymouth
Member – Firm becoming very
stiff pale grey calcareous
mudstone/clay.
15-20 m
Oxford Clay – Stewartby Member 20 m
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Superficial/Bedrock
Stratum and General Description
Maximum Thickness
Aquifer Classification
– Firm becoming very stiff pale to
medium grey smooth silicate
mudstone/clay with subordinate
beds of shell debris.
Oxford Clay – Peterborough
Member – Firm to very stiff is an
organic rich brownish – grey
silicate mudstone/clay,
25 m
Table 11.11 Summary of Encountered Ground Conditions: Claydon Junction to
Aylesbury
Superficial/ Bedrock
Stratum and General Description
Maximum Thickness
Aquifer Classification
Topsoil – Broadly cohesive with
sand and gravel components.
<0.5 m --
Made ground – Re-worked
deposits of natural cohesive and
granular material with varying
clay, sand and gravel
components. Material also
contains varying quantities of
ballast, clinker and ash.
Up to 8 m in
areas of high
embankment.
Generally 0.5 –
2 m
--
Relic topsoil – Stiff dark brown
silty clay with black silty organic
partings.
--
Superficial
Alluvium – Silt, sand and gravel.
Local environment previously
dominated by rivers - soft to firm
light brown mottled grey clay with
orange/brown silt partings.
2 m Secondary A
River Terrace Deposits – Multi-
coloured clayey fine to coarse
sand and gravel.
2 m
Head Deposits – Firm grey
mottled orange slightly sandy
clay.
2 m Secondary
(undifferentiated)
Glacial Deposits – These
deposits are highly localised on
the Sub-section 2E route.
2 m
Bedrock
Kimmeridge Clay – Firm to very
stiff sandy silty clay.
35-40 m Unproductive
Strata
Ampthill Clay: Firm becoming
very stiff smooth or slightly silty
pale to medium grey firm to stiff
clay.
10-20 m
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 30
Superficial/ Bedrock
Stratum and General Description
Maximum Thickness
Aquifer Classification
West Walton Formation: Firm
becoming very stiff dark grey silty
clay interbedded pale grey
mudstone.
10-15 m
Oxford Clay – Weymouth
Member: Firm becoming very stiff
pale grey calcareous
mudstone/clay.
15-20 m
Oxford Clay – Stewartby Member:
Firm becoming very stiff pale to
medium grey smooth silicate
mudstone/clay with subordinate
beds of shell debris.
20 m
Oxford Clay – Peterborough
Member: Firm to very stiff: an
organic rich brownish grey silicate
mudstone/clay.
25 m
Kellaways Formation – Grey
calcareous very silty fine sand/
sandy silt (Kellaways Sand
Member) overlying a firm to stiff
grey clay (Kellaways Clay
Member).
Unknown Secondary A
11.5.6 The following table provides details of mineral safeguarding areas which
could potentially be affected by mobilisation of contamination during
construction/operation of the Project.
Table 11.12 Summary of Potential Mineral Resources from Mineral Safeguarding
Plans
Sub-section Mineral Safeguarding Areas and Geologically Designated Sites
Cherwell District
Council sub-
section
Superficial deposits – Sub-alluvial: Inferred resources a band of
alluvium crossing the Project Area to the east of Bicester.
Aylesbury Vale:
Claydon/Quainton
sub-section
Bedrock deposits – Brick Clay underlying much the East West
portion of the former Varsity line route from Marsh Gibbon to
Verney Junction
Superficial deposits – Sub-alluvial: Inferred resources a band of
alluvium crossing the Project Area to the east of Verney Junction.
River terrace deposits adjacent to the eastern extent of the Sub-
section.
Aylesbury Vale:
Claydon/Quainton
sub-section
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 31
Sub-section Mineral Safeguarding Areas and Geologically Designated Sites
Aylesbury Vale:
Winslow /
Swanbourne sub-
section
Superficial deposits – Glaciofluvial sand and gravel deposits
intersect with the Project in multiple areas surrounding Winslow.
Superficial deposits – Sub-alluvial: Inferred resources a band of
alluvium crossing the Project Area to the north of Winslow.
Aylesbury Vale:
Aylesbury sub-
section
Superficial deposits – Sub-alluvial: Inferred resources a band of
alluvium crossing the Project Area to the north of Waddesdon and
Fleet Marston Farm.
Superficial deposits – River terrace deposits underlie the Project
Area within Aylesbury to the north west of Quarrendon
Wycombe District
Council sub-
section
Superficial deposits – Sub-alluvial: Inferred resources a band of
alluvium adjacent to the Project Area at the northern extent of the
Sub-section.
River terrace deposits a narrow band adjacent to the northern
boundary of the Sub-section.
Milton Keynes
Council sub-
section
River terrace deposits a narrow band to the north of Bletchley
Brickworks (Newton Longville).
As the route branches to the north of Bletchley station it becomes
underlain by Bedrock deposits of Brick Clay with multiple historic
brickworks identified surrounding Milton Keynes.
As the route extends to the east of Bletchley it is underlain by River
terrace deposits and Brick Clay deposits surrounding Fenny
Stratford. Further to the east the former Station Brick and Tile
works and the Woburn sands Brickworks historic clay extraction
sites have been identified.
Central
Bedfordshire
Council sub-
section
Bedrock deposits - Outcrop area of Lower Oxford Clay surrounding
historic clay pits adjacent to Quest clay pit.
Bedrock deposits – Woburn Sands intersect with the Project Area
to the north of Aspley Guise.
Bedford Borough
Council sub-
section
Bedrock deposits - Outcrop area of Lower Oxford Clay surrounding
historic clay pits adjacent to Kempston Hardwick further to the
north of Elstow the route is underlain by River gravel resources.
11.5.7 No Local Geology Sites or RIGs have been identified within 500 m of the
Project Area Boundary.
Ground Stability and Soil Compaction
11.5.8 Geological hazard information has been collated and is summarised in the
following table:
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 32
Table 11.13 Summary of Geological Hazards by Project Sub-section
Geological Hazards Predominant classification
Exceptions and sub-section impacted
Collapsible Ground No hazard to very low hazard --
Compressible
Ground Predominantly no hazard
Alluvial deposits designated as
moderate hazard in Cherwell
District Council, Aylesbury
Vale: Winslow/Swanbourne,
Aylesbury Vale: Aylesbury,
Wycombe District Council,
Milton Keynes Council ,
Central Bedfordshire Council ,
Bedford Borough Council sub-
sections
Dissolution No hazard to low hazard --
Landslide Predominantly very low hazard
A band in the Aylesbury Vale:
Claydon/Quainton sub-section
designated moderate hazard
Running
Sand
Predominantly no hazard in
Cherwell District Council,
Aylesbury Vale:
Claydon/Quainton, Aylesbury
Vale: Aylesbury and Wycombe
District Council sub-sections.
Predominantly very low hazard
in Aylesbury Vale:
Winslow/Swanbourne, Milton
Keynes Council, Central
Bedfordshire Council and
Bedford Borough Council sub-
sections.
Variable - with multiple areas
of alluvium designated low
hazard and areas of river
terrace deposits and glacial till
designated very low hazard
across all sub-sections
Shrinking or Swelling
Clay
Predominantly designated
moderate hazard associated
with Oxford Clay within
Cherwell District Council,
Aylesbury Vale:
Winslow/Swanbourne,
Aylesbury Vale:
Claydon/Quainton sub-
sections becoming low to the
north west of Aylesbury within
Aylesbury Vale: Aylesbury
sub-section
Project within Wycombe
District Council sub-section
predominantly designated no
hazard with bands designated
very low hazard and moderate
hazard in the north of
Wycombe District Council sub-
section
Radon Hazards
The majority of the route is
designated as a lower
probability radon area, with
less than 1 % of homes
exceeding the action level.
There are however areas of
intermediate designation in the
Aylesbury, Wycombe District
Council and Milton Keynes
Council sub-sections.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 33
Geological Hazards Predominant classification
Exceptions and sub-section impacted
Mining Hazards
According to Coal Authority
records, no part of the entire
Project Area including all sub-
sections lies within a zone of
likely physical influence at the
surface from any past or
present underground workings.
--
Hydrology
11.5.9 Numerous watercourses intersect with the Project Area within each of the
sub-sections. These watercourses include the following Environment
Agency designated main rivers, ordinary rivers and surface water features
such as lakes.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 34
Table 11.14 Summary of Controlled Waters Receptors by Sub-section
Sub-section
Controlled water receptors including Environment Agency main rivers intersecting with Study Area
Discharge to Aquifer classification(s)
Cherwell
District
Council
sub-section
Langford Brook and Launton Brook both
Main Rivers
Langford Brook discharges to the River
Ray, Launton Brook discharges to
Cutters Brook
Superficial : Predominantly not classified
aside from Alluvium classified as Secondary
A Aquifer
Bedrock: Predominantly Unproductive Strata
Limited extent underlain by Secondary A
Aquifer
Aylesbury
Vale:
Claydon /
Quainton
sub-section
East West Alignment
Beaconhill Ditch Main River, Fleet Marston
Brook Main River
Grebe Lake
Calvert Jubilee Local Nature Reserve
Four tributaries of Padbury Brook
Claydon Brook
North South Alignment
Muxwell Brook Main River
Two ordinary watercourses
Greatmoor Ditch
The River Ray Main River
Doddershall Brook Main River
Beaconhill Ditch discharges to Cutters
Brook
Claydon Brook discharges to Padbury
Brook
The two ordinary watercourses
discharge to Muxwell Brook and the
River Ray
Greatmoor Ditch discharges to the River
Ray
Doddershall Brook confluences with
Tetchwick Brook
Superficial : Predominantly not classified
aside from Alluvium and River Terrace
Deposits classified as Secondary A Aquifers
Diamicton classified as Unproductive Strata
Bedrock: predominantly Unproductive Strata
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 35
Sub-section
Controlled water receptors including Environment Agency main rivers intersecting with Study Area
Discharge to Aquifer classification(s)
Aylesbury
Vale:
Winslow /
Swanbourne
sub-section
None --
Superficial: Predominantly classified as
Unproductive Strata aside from Alluvium and
Glaciofluvial Deposits classified as
Secondary A Aquifer. Limited bands
designated as Secondary (undifferentiated)
Aquifers
Bedrock: Unproductive Strata
Aylesbury
Vale:
Aylesbury
sub-section
Fleet Marston Brook Main River
River Thame (mapping indicates this river
has been subject to historic diversion) Main
River
Bear Brook Main River
Coldharbour Way Ditch Main River
California Brook Main River
Southcourt Brook
Stoke Brook Main River
Fleet Marston Brook discharges to the
River Thame
Bear Brook discharges to the River
Thame
California Brook discharges to Bear
Brook
Southcourt Brook confluences with Bear
Brook
Stoke Brook confluences with Bear
Brook
Superficial: Alluvium and River Terrace
Deposits classified as Secondary A Aquifer.
Limited bands designated as Secondary
(undifferentiated) Aquifers
Bedrock: Predominantly Unproductive Strata
with bands of Secondary A and Secondary
(undifferentiated) Aquifers. A Principal
Aquifer is mapped within Aylesbury (though
outside the Project)
Wycombe
District
Council
sub-section
The Terrick Brook Main River
Scotsgrove Brook ordinary watercourse
Three ordinary watercourses
Scotsgrove Brook confluences with
Terrick Brook
The three ordinary watercourses
confluence with Horsenden Stream
Superficial: Alluvium and River Terrace
Deposits classified as Secondary A Aquifers.
Limited bands designated as Secondary
(undifferentiated) Aquifers
Bedrock: Unproductive Strata with the Chalk
in the south of the Sub-section identified as a
Principal Aquifer.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 36
Sub-section
Controlled water receptors including Environment Agency main rivers intersecting with Study Area
Discharge to Aquifer classification(s)
Milton
Keynes
Council
sub-section
The River Ouse Main River
Unnamed ordinary watercourse 80 m to the
south of the Project
Loughton Brook ordinary watercourse
Unnamed tributary of Loughton Brook
ordinary watercourse
The Grand Union Canal
The River Ouzel Main River
The River Great Ouse Main River
Caldecotte Lake
Five minor watercourses to the east of Fenny
Station
The unnamed watercourse discharges
to Water Easton Brook and River Ouzel
The five minor watercourses to the east
of Fenny Station discharge to the River
Ouzel
Superficial: Alluvium, Stoke Goldington
Member, Felmersham Member and River
Terrace Deposits classified as Secondary A
Aquifers. Limited bands of Head Deposits
designated as Secondary (undifferentiated)
Aquifers.
Oadby Member designated Unproductive
Strata
Bedrock: Predominantly Unproductive Strata
with bands of Secondary A Aquifers
associated with the Kellaways Formation
Central
Bedfordshir
e Council
sub-section
None --
Superficial: Alluvium and Stoke Goldington
Member classified as Secondary A Aquifers.
Head Deposits designated as Secondary
(undifferentiated) Aquifers.
Oadby Member designated Unproductive
Strata
Bedrock: Unproductive Strata
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 37
Sub-section
Controlled water receptors including Environment Agency main rivers intersecting with Study Area
Discharge to Aquifer classification(s)
Bedford
Borough
Council
sub-section
Elstow Brook
The River Great Ouse
Minor ordinary watercourses
The majority of minor ordinary
watercourses discharge to Elstow Brook
Superficial: Alluvium, Stoke Goldington
Member and Felmersham Member classified
as Secondary A Aquifers. Head Deposits
designated as Secondary (undifferentiated)
Aquifers.
Bedrock: Predominantly Unproductive Strata
with Secondary A Aquifers associated with
the Kellaways Sand Member.
A Principal Aquifer of the Greater Oolite
Group within Bedford.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 38
11.5.10 For the purposes of the assessment these surface water features will be
considered sensitive water quality receptors. The locations of these are
shown on Figures 13.1-13.8 (Water Constraints Map).
11.5.11 The following sensitive ecological receptors have been identified within 1
km of the Project Boundary:
Table 11.15 Summary of Designated Ecological Sites by Sub-section
Sub-section Off-site sensitive ecological receptors
Cherwell District
Council Upper Thames Tributaries
Aylesbury Vale:
Claydon/Quainton Sites of Special Scientific Interest (SSSI): Sheephouse Wood and
Finemere Wood
Wycombe District
Council
Special Area of Conservation (SAC): The Chilterns
Two SSSIs: Ellesborough and Kimble Warrens
Milton Keynes
Council Local Nature Reserve named the Blue Lagoon
11.5.12 On review of the characteristics of each of these sites and their proximity
to the Project, the potential for soils/geology-related impact upon these
receptors is not considered likely to be significant. No further
consideration of ecological receptors is made in this chapter; full
assessment and details are given in Chapter 9 (Ecology).
Potential for Re-use of Soils and Waste Soils
11.5.13 The efficient use of resources is stipulated in legislation, policy and best
practice guidance. Network Rail’s Sustainable Procurement Policy311
states that in terms of waste, the aim is for “zero waste to landfill and
increased use of sustainable and recycled materials”.
11.5.14 A combined Site Waste Management Plan (SWMP) and Materials
Management Plan (MMP) tool has been created for the Project to forecast
and confirm the ultimate destination of excess/unsuitable soil arisings
311 Network Rail, Sustainable Development Strategy (2013-2024), Version 0.71,
http://www.networkrail.co.uk/browse%20documents/strategicbusinessplan/cp5/supporting%20documents/transforming%20network%20rail/sustainable%20development%20strategy.pdf [Online, 13 November 2015]
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 39
generated during construction of the Project. All materials which are to be
sent to landfill will be accompanied by a justification.
11.5.15 Information on the nature of the soils within the Project will be collected
during detailed design to undertake a detailed assessment of the
suitability of existing materials for re-use and the appropriate destination
for waste soils. In the meantime, the general principle that will be adhered
to is that the material must be suitable for its proposed use or offsite
disposal destination, both geotechnically and in terms of contamination.
The stockpiling of potentially contaminated ballast, for example adjacent
to a watercourse, would be considered a risk to a sensitive receptor (the
surface water), and would therefore not be carried out.
11.5.16 Another risk for consideration is the potential for some of the existing
railway ballast/fill material to be contaminated. Frequently railway land can
be impacted by asbestos, metals, metalloids and their compounds and
ash, arising from historic construction. In addition, historic operation of the
railway can also lead to contamination. This contamination is most likely
to occur in areas where trains have been stationary (sidings and stations).
This contamination could result in the material being classified as
hazardous waste following earthworks. Network Rail follow a procedure
for handling used ballast (NR/L3/ENV/044) that requires the waste to be
correctly categorised and handled. The standard is to guard against
pollution and to fulfil statutory requirements, such as the duty of care to
the handling, transport and management of waste, and has been agreed
with the Environment Agency
Ground Contamination
11.5.17 For the Project, key potential contamination sources are considered to be:
Contamination associated with the existing railway, as works proposed require modernisation of existing railway much of which predates the earliest available historical maps (c1880s);
Areas of historic clay extraction and brick manufacturing have been identified surrounding Calvert, Stewartby, Kempston Hardwick and Bletchley. Some of these former brick fields have subsequently been put to use as landfills, both historically and up to the present day; and
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 40
Historical potentially contaminative industries such as gas works sites and sewage farms adjacent to the Project where it passes urban areas such as Bicester, Aylesbury and Bletchley.
11.5.18 Ground conditions data from the initial round of intrusive
investigation312,313,314,315 found:
No exceedances of the applied generic assessment criteria were recorded as part of the soils testing undertaken;
No soil leachabilty or groundwater analytical testing was undertaken; and
Asbestos was not detected by the analytical laboratory in any of the soil samples recovered during any phases of investigation.
Environmental Receptors
11.5.19 The following sensitive receptors have been identified as relevant to the
assessment of contamination in respect of the Project.
Human Receptors
11.5.20 Public access to the parts of the Project Area where exposure is likely to
occur (such as earthworks during construction or operational railway
infrastructure during operation) during construction and operation will be
limited. The Project will provide fencing to prevent unauthorised access or
trespassing to these parts of the Project Area during construction and
operation. The only human health receptors with direct access to the soils
underlying the Project are considered to be construction and maintenance
workers, potentially undertaking excavation. Exposure is unlikely to occur
in the parts of the Project Area that members of the public (e.g. footpath
users, farmers, station users, road users) will have access to during
construction or operation.
312 WSP | Parsons Brinckerhoff, (2015). East West Rail - Phase 2, Ground Investigation Report, Phase 2A, Claydon Junction
to Jarvis Lane. Bicester.
313 WSP | Parsons Brinckerhoff, (2015). East West Rail - Phase 2, Ground Investigation Report, Phase 2B, Part Single Bi-
Directional Freight & Part Disused Line.
314 WSP | Parsons Brinckerhoff, (2015). East West Rail - Phase 2, Ground Investigation Report, Phase 2E, Aylesbury Central
to Calvert Junction.
315 WSP | Parsons Brinckerhoff, (2015). East West Rail - Phase 2, Ground Investigation Report, Phase 2F, Aylesbury to
Princes Risborough.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 41
11.5.21 Off-site human health receptors including residential housing in both
estates and individual properties have been identified adjacent to the
Project Area at the following locations:
Table 11.16 Off-Site Human Health Receptors
Sub-section Off-Site Residential Areas
Cherwell District
Council Bicester, Launton
Aylesbury Vale:
Claydon /
Quainton Charndon, Twyford, Steeple Claydon, Verney Junction
Aylesbury Vale:
Winslow /
Swanbourne Winslow, Newton Longville
Aylesbury Vale:
Aylesbury Waddeson, Aylesbury
Wycombe
District Council Marsh
Milton Keynes
Council Bletchley, Woburn Sands
Central
Bedfordshire
Council
Woburn Sands, Aspley Guise, Husborne Crawley, Brogborough,
Lidlington
Bedford
Borough Council Stewartby, Kempston
11.5.22 The following human health receptors have therefore been considered:
On-site:
o Construction workers; and
o Future maintenance workers.
Off-site:
o Residents in adjacent properties during construction and operation; and
o Recreational users of adjacent land, e.g. footpaths, during construction and operation.
11.5.23 The principal contaminant exposure pathways to on-site (within the
Project Area) human receptors are:
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 42
Dermal contact with, inhalation of and / or ingestion of contaminants in soil and water; and
Inhalation of ground gases or asbestos fibres.
11.5.24 The principal contaminant exposure pathways to off-site (beyond the
Project Boundary but within 500 m of it ) human receptors are:
Dermal contact with and / or ingestion of contaminants in windblown soil-derived dusts and water which may have migrated off-site;
Inhalation of contaminants in windblown dust; and
Inhalation of vapours or asbestos fibres which may have migrated off-site.
Controlled Water Receptors
11.5.25 The following potential controlled water receptors have been identified:
Main Rivers which cross the line of the railway – Launton Brook, Langford Brook, Beaconhill Ditch, Fleet Marston Brook, Muxwell Brook, the River Ray, Doddershall Brook, Fleet Marston Brook, the River Thame, Bear Brook, Coldharbour Way Ditch, Southcourt Brook, Stoke Brook, the Terrick Brook, the River Ouse, the River Ouzel, the River Great Ouse, Elstow Brook;
Ordinary water courses which cross the line of the railway – Scotsgrove Brook, Loughton Brook, multiple unnamed tributaries;
Surface water bodies adjacent to the Project – Grebe Lake, the Grand Union Canal and several smaller ponds identified during ecology surveys (further information can be found in Chapter 9 (Ecology));and
Sensitive superficial and bedrock aquifers underlying the Project.
11.5.26 Principal contaminant migration pathways for controlled waters receptors
comprise:
Surface runoff;
Infiltration and lateral migration; and
Infiltration and vertical migration.
Property Receptors
11.5.27 Property receptors located within the Project Area may have the potential
to be affected by contamination during both the construction and
operational phases of the Project. The following on-site property
receptors have been identified:
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 43
Station buildings including below ground utility services – Winslow Station; and
Railway platforms – Aylesbury Vale Parkway, Woburn Sands, Ridgmont, and Princes Risborough stations.
11.5.28 The following off-site property receptors have been identified:
Buildings including residential homes and commercial properties within 500 m of the Project Boundary.
11.5.29 Potential pathways comprise:
Direct contact with aggressive ground conditions; and
Migration through permeable ground/via utility corridors/cracks in floor slab/service entry points – accumulation of gases and vapours in confined spaces generating potentially explosive atmosphere.
Preliminary Conceptual Site Model
11.5.30 A Conceptual Site Model (CSM) identifies the potential or known sources
of contamination, receptors and migration or exposure pathways. Where
all three are present or considered likely to be present, i.e. source –
pathway – receptor, this is termed a Potential Contaminant Linkage
(PCL). Three preliminary CSMs (baseline, construction and operation)
were developed for the Project using the baseline information summarised
above. The baseline Conceptual Site Models (CSM) for ground
contamination, subdivided by reporting sub-section, are presented in the
following section. All potential contaminant linkages identified have been
displayed within the relevant baseline CSM tables. Pathways relevant to
human health receptors including the risk of direct ingestion of soils, direct
contact with groundwater, and inhalation of vapours have largely been
assessed as low risk. Pathways relevant to controlled waters receptors
such as infiltration and leaching have also been assessed as Low
depending on the underlying geology of the Project in the sub-section.
11.5.31 A summary of the PCLs is given in the following sections and in Table
11.17 to Table 11.24.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 44
Table 11.17 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Cherwell District Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing
contamination within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Dermal contact/ ingestion/
inhalation of contaminated dust
or soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties. Medium Low likelihood
Moderate / low
risk
Recreational users of adjacent
land Medium Low likelihood
Moderate / low
risk
Maintenance workers on existing
line Minor Low likelihood Very low risk
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways
Superficial Secondary A aquifer
(Alluvial deposits)
Launton Brook, Langford Brook
Minor Low likelihood Very low risk
Geological hazards
(ground stability)
Collapsible ground Existing on- and off-site structures Medium Unlikely Low risk
Compressible ground Existing on- and off-site structures Medium Low likelihood Moderate / low
risk
Ground dissolution Existing on- and off-site structures Medium Unlikely Low risk
Landslide Existing on- and off-site structures Medium Unlikely Low risk
Geological hazards (ground stability)
Running sand Existing on- and off-site structures Medium Unlikely Low risk
Shrinking / swelling clay Existing on- and off-site structures Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 45
Table 11.18 Baseline Phase Conceptual Site Model Findings: Potential Contaminant Linkages within the Aylesbury Vale: Claydon/Quainton sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing
contamination within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Medium Low likelihood Moderate/ Low
risk
Recreational users of adjacent
land
Medium Low likelihood Moderate/ Low
risk
Maintenance workers on existing
line
Minor Low likelihood Very low risk
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways
East-West Alignment:
Beaconhill Ditch Main River, Fleet Marston Brook Main River
Grebe Lake
Calvert Jubilee Local Nature Reserve
Four tributaries of Padbury Brook
Claydon Brook
North-South Alignment:
Muxwell Brook Main River
Two ordinary watercourses
Greatmoor Ditch
The River Ray Main River
Doddershall Brook Main River Beaconhill Ditch, Little Marsh Ditch, Tetchwick Brook and Fleet Marston Brook.
Minor Low likelihood Very low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 46
Source of risk Pathway / action Receptor Consequence Probability Risk
Superficial Secondary A aquifer
(Alluvium & River Terrace
Deposits)
Minor Low likelihood Very low risk
Infill material
associated with the
former Calvert clay
pits/brick works
Migration of ground gas through
permeable ground/ utility
corridors/ cracks in floor slabs/
service entry points with
potential accumulation to
explosive atmospheres
Built environment receptors:
Buildings and, subsurface
structures including utilities
surrounding the Project Area.
Mild Low likelihood Low risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate into
the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing on- and off-site structures Medium Unlikely Low risk
Compressible ground Existing on- and off-site structures Medium Unlikely Low risk
Ground dissolution Existing on- and off-site structures Medium Unlikely Low risk
Landslide Existing on- and off-site structures Medium Low likelihood Moderate / low
risk
Running sand Existing on- and off-site structures Medium Unlikely Low risk
Shrinking / swelling clay Existing on- and off-site structures Medium Low likelihood Moderate / low
risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 47
Table 11.19 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Aylesbury Vale: Winslow/Swanbourne sub-section.
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing
contamination within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Mild Low likelihood Low risk
Recreational users of adjacent
land
Mild Low likelihood Low risk
Maintenance workers on existing
line
Minor Low likelihood Very low risk
Surface run-off
Migration of contaminants through
granular or fractured materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways
Horwood Brook
Unnamed minor watercourse to
the east of Whaddon Road.
Minor Low likelihood Very low risk
Superficial Secondary A aquifer Minor Low likelihood Very low risk
Buried waste of
unknown provenance
at the active landfill at
Newton Longville
Project and the
surrounding historic
landfills.
Migration of ground gas through
permeable ground/ utility
corridors/ cracks in floor slabs/
service entry points with potential
accumulation to explosive
atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate into
the Project Area
Subsurface infrastructure /
foundations
Mild Low likelihood Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 48
Source of risk Pathway / action Receptor Consequence Probability Risk
Geological hazards
(ground stability)
Collapsible ground Existing on- and off-site structures Medium Unlikely Low risk
Geological hazards
(ground stability)
Compressible ground Existing on- and off-site structures Medium Low Moderate / low
risk
Ground dissolution Existing on- and off-site structures Medium Unlikely Low risk
Landslide Existing on- and off-site structures Medium Unlikely Low risk
Running sand Existing on- and off-site structures Medium Unlikely Low risk
Shrinking / swelling clay Existing on- and off-site structures Medium Low Moderate / low
risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 49
Table 11.20 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Aylesbury Vale: Aylesbury sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground
of unknown
provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Mild Low likelihood Low risk
Maintenance workers on
existing line
Minor Low likelihood Very low risk
Surface run-off
Migration of contaminants through
granular or fractured materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways e.g. newly-created
service runs.
Fleet Marston Brook
The River Thame
Bear Brook
Coldharbour Way Ditch
California Brook
Stoke Brook
Minor Low likelihood Very low risk
Superficial Secondary A aquifer
Bedrock Principal & Secondary
A aquifers
Medium Low likelihood Moderate / low
risk
Buried waste of
unknown provenance
adjacent to the Project
Area including
Channel Infill
associated with the
River Thame.
Migration of ground gas through
permeable ground/ utility
corridors/ cracks in floor slabs/
service entry points with potential
accumulation to explosive
atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Off-site human health receptors
in properties adjacent to the
Project
Severe Low likelihood Moderate risk
Migration of landfill leachate into
the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards Collapsible ground Existing on- and off-site Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 50
Source of risk Pathway / action Receptor Consequence Probability Risk
(ground stability) structures
Geological hazards
(ground stability)
Compressible ground Existing on- and off-site
structures
Medium Low likelihood Moderate / low
risk
Ground dissolution Existing on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing on- and off-site
structures
Medium Low likelihood Moderate / low
risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 51
Table 11.21 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Wycombe District Council sub-section.
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground
of unknown
provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Mild Low likelihood Low risk
Maintenance workers on existing
line
Minor Low likelihood Very low risk
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways e.g. newly-created
service runs.
Terrick Brook and Scotsgrove
Brook
Minor Low likelihood Very low risk
Superficial Secondary A &
Principal Bedrock aquifers
Medium Low likelihood Moderate / low
risk
Buried waste of
unknown provenance
adjacent to the Project
Area associated with
historic landfilling.
Migration of ground gas through
permeable ground/ utility
corridors/ cracks in floor slabs/
service entry points with
potential accumulation to
explosive atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate into
the Project Area
Subsurface infrastructure/
foundations
Mild Low likelihood Low risk
Geological hazards Collapsible ground Existing on- and off-site structures Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 52
Source of risk Pathway / action Receptor Consequence Probability Risk
(ground stability)
Geological hazards
(ground stability)
Compressible ground Existing on- and off-site structures Medium Low likelihood Moderate / low
risk
Ground dissolution Existing on- and off-site structures Medium Unlikely Low risk
Landslide Existing on- and off-site structures Medium Unlikely Low risk
Running sand Existing on- and off-site structures Medium Unlikely Low risk
Shrinking / swelling clay Existing on- and off-site structures Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 53
Table 11.22 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Milton Keynes Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground
of unknown
provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Mild Low likelihood Low risk
Maintenance workers on existing
line
Minor Low likelihood Very low risk
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways e.g. newly-created
service runs.
The River Great Ouse, the Blue
Lagoon LNR, Caldecotte Lake
and the Grand Union Canal
Minor Low likelihood Very low risk
Superficial & Bedrock Secondary
A aquifers
Medium Low likelihood Moderate / low
risk
Buried waste of
unknown provenance
at the active landfill at
Newton Longville site
and the surrounding
historic landfills.
Migration of ground gas through
permeable ground/ utility
corridors/ cracks in floor slabs/
service entry points with
potential accumulation to
explosive atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate into
the Project Area
Subsurface infrastructure/
foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing on- and off-site structures Medium Unlikely Low risk
Compressible ground Existing on- and off-site structures Medium Low likelihood Moderate / low
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 54
Source of risk Pathway / action Receptor Consequence Probability Risk
risk
Ground dissolution Existing on- and off-site structures Medium Unlikely Low risk
Geological hazards
(ground stability)
Landslide Existing on- and off-site structures Medium Unlikely Low risk
Running sand Existing on- and off-site structures Medium Unlikely Low risk
Shrinking / swelling clay Existing on- and off-site structures Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 55
Table 11.23 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Central Bedfordshire Council sub-section.
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground
of unknown
provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of windblown dust,
fibres or vapours.
Members of the public within the
vicinity of the Project
Mild Low likelihood Low risk
Maintenance workers on existing
line
Minor Low likelihood Very low risk
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways e.g. newly-created
service runs.
Controlled waters: The Broughton
Brook (ordinary watercourse)
Tertiary unnamed rivers in the
vicinity.
Natural Ponds
Minor Low likelihood Very low risk
Superficial Secondary A aquifer Mild Low likelihood Low Risk
Buried waste of
unknown provenance
within the
surrounding historic
landfills.
Migration of ground gas through
permeable ground/ utility
corridors/ cracks in floor slabs/
service entry points with
potential accumulation to
explosive atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate into
the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards Collapsible ground Existing on- and off-site structures Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 56
Source of risk Pathway / action Receptor Consequence Probability Risk
(ground stability)
Geological hazards
(ground stability)
Compressible ground Existing on- and off-site structures Medium Low likelihood Moderate / low
risk
Ground dissolution Existing on- and off-site structures Medium Unlikely Low risk
Landslide Existing on- and off-site structures Medium Unlikely Low risk
Running sand Existing on- and off-site structures Medium Unlikely Low risk
Shrinking / swelling clay Existing on- and off-site structures Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 57
Table 11.24 Baseline Conceptual Site Model Findings: Potential Contaminant Linkages within the Bedford Borough Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground
of unknown
provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Medium Unlikely Low risk
Maintenance workers on existing
line
Minor Low likelihood Very low risk
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways e.g. newly-created
service runs.
Groundwater (SPZ): Superficial
Secondary A and bedrock
Principal aquifers
Numerous water bodies within the
sub-section which cross the
Project Area.
The River Ouse and an unnamed
river.
Medium Low likelihood Moderate / low
risk
Buried waste of
unknown provenance
within and
surrounding the
historic landfills.
Migration of ground gas through
permeable ground/ utility
corridors/ cracks in floor slabs/
service entry points with
potential accumulation to
explosive atmospheres
Built environment receptors:
Buildings and subsurface
structures including utilities
surrounding the Project Area.
Mild Low likelihood Low risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate into
the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing on- and off-site structures Medium Unlikely Low risk
Compressible ground Existing on- and off-site structures Medium Low likelihood Moderate / low
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 58
Source of risk Pathway / action Receptor Consequence Probability Risk
risk
Ground dissolution Existing on- and off-site structures Medium Unlikely Low risk
Geological hazards
(ground stability)
Landslide Existing on- and off-site structures Medium Unlikely Low risk
Running sand Existing on- and off-site structures Medium Unlikely Low risk
Shrinking / swelling clay Existing on- and off-site structures Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 59
11.6 Assessment of Effects
Construction
11.6.1 This section considers the assessment of the construction phase of the
Project. The following potential sources of contamination, receptors and
exposure/migration pathways have been identified:
The disturbance of existing contamination associated with historic/current landfilling/other land uses and the introduction of new pathways for migration;
Excavation, storage and removal of potentially contaminated materials;
The introduction of potentially polluting substances through storage of chemicals, solvent and the use of fuels/oils;
The potential for off-site migration of contaminants and increased suspended solid loading in surface water run-off;
The introduction of human health receptors (construction/future maintenance workers); and
The potential for migration of contaminants to groundwater (Project Area underlain by Principal aquifer within Wycombe District Council and Bedford Borough Council sub-sections, with a groundwater SPZ identified within Bedford), taking into account the minor works currently proposed in these sub-sections.
11.6.2 Temporary structures will be established within construction compounds
of varying sizes including welfare facilities, offices and storage buildings.
These structures are assumed to be modular shipping container type units
which are unlikely to possess below ground foundations. These structures
have therefore been excluded as ‘built environment’ receptors. The new
station at Winslow and the identified platform extensions have been
included. Further information on the proposed works during construction
can be found in Chapter 2 (Project Description).
11.6.3 In addition to the mitigation measures set out in Section 11.2 (Limitations
and Assumptions) the following assumptions have been incorporated into
the assessment of the construction phase of works:
Appropriate best practice techniques and guidance such as CLR11 and the Environment Agency guidance on Piling into Contaminated
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 60
Sites316 will be adhered to in order to minimise and prevent pollution being introduced or mobilised as a result of the Project;
Appropriate working practices will be adopted such as the use of dust suppression during dry site conditions to limit off-site dust dispersal;
Contamination was not encountered during the various phases of intrusive ground investigation, though it may be present associated with historic land uses in the vicinity of the Project. It has been assumed that during the construction phase, potentially contaminated soils encountered will be appropriately managed.
Where material is removed due to its chemical unsuitability for retention at the site, full records should be maintained and a verification report prepared following Environment Agency guidance;
A combined SWMP and MMP tool will be used for the Project to forecast and confirm the ultimate destination of arisings generated during construction phase of the Project;
There is the potential for groundwater flow to be impacted by deep excavation and the use of piling/drilling during the construction phase. This is particularly likely during the construction of the new station at Winslow, the platform extensions and the construction of new bridges;
Piling risk assessments will be prepared where piling is proposed within a groundwater source protection zone, within 8 m of an Environment Agency main river or close to potential sources of contamination such as landfills or chemical works;
The majority of the Project Area in which excavation/construction is proposed is underlain by unproductive strata and much of the work to be undertaken requires only limited shallow excavation with the construction of near surface structures (tracking/ signalling); and
Aside from the discussed localised areas of construction no changes to the ground surface composition and thus water infiltration rates are anticipated to be required within the Project Area.
11.6.4 There is the potential for off-site contamination in the form of
contaminated soils, leachate and ground gas to impact receptors
(construction/maintenance workers) within the Project Area associated
with historic/contemporary landfilling in the vicinity of the Project and other
historic sources.
11.6.5 The following Tables 11.25 to 11.32 present the CSM findings for the
construction phase.
316 Environment Agency. 2002. Piling into Contaminated Sites.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 61
Table 11.25 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Cherwell District Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing
contamination within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Recreational users of adjacent
land
Mild Likely Moderate / Low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours..
Construction workers Mild Low likelihood Low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in
suspended silts into
surface run-off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along
preferential pathways e.g.
newly-created service runs.
Superficial Secondary A aquifer
(Alluvial deposits)
Launton Brook and Langford
Brook
Minor Likely Low risk
Geological hazards Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 62
Source of risk Pathway / action Receptor Consequence Probability Risk
(ground stability) Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 63
Table 11.26 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Claydon/Quainton sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing
contamination within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Recreational users of adjacent
land
Mild Likely Moderate / Low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Construction workers Mild Low likelihood Low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along
preferential pathways e.g.
newly-created service runs.
Multiple surface water courses as
listed in Table 11.14.
Minor Low likelihood Low risk
Superficial Secondary A aquifer
(Alluvium & River Terrace
Deposits)
Minor Low likelihood Very low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 64
Source of risk Pathway / action Receptor Consequence Probability Risk
Infill material
associated with the
former Calvert clay
pits/brick works
Migration of ground gas
through permeable ground/
utility corridors/ cracks in
floor slabs/ service entry
points with potential
accumulation to explosive
atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Construction workers Severe Low likelihood Moderate risk
Migration of landfill leachate
into the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 65
Table 11.27 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Winslow/Swanbourne sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing
contamination within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Recreational users of adjacent
land
Mild Likely Moderate/ Low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Construction workers Mild Low likelihood Low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along
preferential pathways e.g.
newly-created service runs.
Superficial Secondary A aquifer
Horwood Brook
An unnamed minor watercourse
to the east of Whaddon Road.
Minor Likely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 66
Source of risk Pathway / action Receptor Consequence Probability Risk
Buried waste of
unknown provenance
at the active landfill at
Newton Longville
Project and the
surrounding historic
landfills.
Migration of ground gas
through permeable ground/
utility corridors/ cracks in
floor slabs/ service entry
points with potential
accumulation to explosive
atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Construction workers Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate
into the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low Moderate / low risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Low Moderate / low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 67
Table 11.28 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Aylesbury sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground
of unknown
provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Mild Likely Moderate / Low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Construction workers Mild Low likelihood Low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along
preferential pathways e.g.
newly-created service runs.
Fleet Marston Brook
The River Thame
Bear Brook
Coldharbour Way Ditch,
California Brook
Stoke Brook
Minor Likely Low risk
Superficial Secondary A aquifer
Bedrock Principal & Secondary A
aquifers
Medium Likely Moderate risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 68
Source of risk Pathway / action Receptor Consequence Probability Risk
Buried waste of
unknown provenance
adjacent to the Project
Area including
Channel Infill
associated with the
River Thame.
Migration of ground gas
through permeable ground/
utility corridors/ cracks in
floor slabs/ service entry
points with potential
accumulation to explosive
atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Construction workers Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate
into the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 69
Table 11.29 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Wycombe District Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground
of unknown
provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Mild Likely Moderate/ Low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Construction workers Mild Low likelihood Low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along
preferential pathways e.g.
newly-created service runs.
Terrick Brook and Scotsgrove
Brook
Minor Likely Low risk
Superficial Secondary A &
Principal Bedrock aquifers
Medium Low likelihood Moderate risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 70
Source of risk Pathway / action Receptor Consequence Probability Risk
Buried waste of
unknown provenance
adjacent to the Project
Area associated with
historic landfilling.
Migration of ground gas
through permeable ground/
utility corridors/ cracks in
floor slabs/ service entry
points with potential
accumulation to explosive
atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Construction workers Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate
into the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 71
Table 11.30 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Milton Keynes Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground
of unknown
provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Mild Likely Moderate / Low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Construction / Maintenance
workers
Minor Low likelihood Low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials. Leaching /
migration of contaminants
through Made Ground and
along preferential pathways
e.g. newly-created service
runs.
The River Great Ouse, the Blue
Lagoon LNR, Caldecotte Lake
and the Grand Union Canal
Minor Likely Low risk
Superficial & Bedrock Secondary
A aquifers
Medium Low likelihood Moderate / low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 72
Source of risk Pathway / action Receptor Consequence Probability Risk
Buried waste of
unknown provenance
at the active landfill at
Newton Longville site
and the surrounding
historic landfills.
Migration of ground gas
through permeable ground/
utility corridors/ cracks in
floor slabs/ service entry
points with potential
accumulation to explosive
atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Construction workers Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate
into the Project Area
Subsurface infrastructure /
foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 73
Table 11.31 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Central Bedfordshire Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties.
Mild Likely Moderate / Low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Construction workers Mild Low likelihood Low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along
preferential pathways e.g.
newly-created service runs.
Broughton Brook (ordinary
watercourse)
Minor Likely Low risk
Superficial Secondary A aquifer Mild Likely Moderate / low risk
Buried waste of
unknown provenance
within the surrounding
Migration of ground gas
through permeable ground/
utility corridors/ cracks in
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Mild Low likelihood Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 74
Source of risk Pathway / action Receptor Consequence Probability Risk
historic landfills. floor slabs/ service entry
points with potential
accumulation to explosive
atmospheres
Project Area.
Construction workers Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate
into the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 75
Table 11.32 Construction Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Bedford Borough Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Existing contaminants
within Made Ground
of unknown
provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Off-site residents of adjacent
properties. Mild Likely Moderate / Low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust,
fibres or vapours.
Construction workers Mild Low likelihood Low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along
preferential pathways e.g.
newly-created service runs.
Groundwater (SPZ): Superficial
Secondary A and bedrock
Principal aquifers
Medium Likely Moderate risk
Numerous water bodies within the
sub-section which cross the
Project Area.
The River Ouse and an unnamed
river.
Mild Likely Moderate / low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 76
Source of risk Pathway / action Receptor Consequence Probability Risk
Buried waste of
unknown provenance
within and
surrounding the
historic landfills.
Migration of ground gas
through permeable ground/
utility corridors/ cracks in
floor slabs/ service entry
points with potential
accumulation to explosive
atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Construction workers Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project Severe Low likelihood Moderate risk
Migration of landfill leachate
into the Project Area
Subsurface infrastructure /
foundations Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures Medium Low likelihood Moderate / low risk
Ground dissolution Existing and new, on- and off-site
structures Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 77
Construction Phase Impact Assessment
11.6.6 The soils and geology impact assessment has been undertaken by
comparing the potential land contamination risks at the baseline stage to
those predicted during construction; these are summarised by sub-section
in Table 11.33 to Table 11.40. There is likely to be increased windblown
dust as a result of the stripping of topsoil, vegetation clearance,
earthworks and the movement of heavy plant. There is also the potential
for increased runoff with a high sediment load to impact surface water
receptors. The previously discussed mitigation measures are again
considered to ameliorate these impacts to an extent. A summary of the
impacts of the Project upon geology both as a resource and the physical
effects (ground stability) of the development subdivided by sub-section is
also discussed below each table.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 78
Table 11.33 Construction Phase Land Contamination Impact Assessment for the Cherwell District Council sub-section
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminated windblown
dust.
- Moderate / Low risk
Construction related contaminants
may have the potential to impact
off-site residents; dust control
measures assumed.
Minor adverse
Exposure of off-site residents
to existing contaminants via
windblown dust.
Moderate/ Low risk Moderate / Low risk
Existing contamination could
potentially be mobilised during
earthworks. Dust control measures
assumed
Neutral
Exposure of construction
workers to construction
related contaminants
- Low risk
Construction workers are assumed
to be equipped with PPE and
adhering to safe systems of work.
Minor adverse
Exposure of construction
workers to existing
contamination disturbed
during earthworks
- Low risk
Construction workers are assumed
to be equipped with PPE and
adhering to safe systems of work.
Minor adverse
Pollution of surface water
courses Very low risk Low risk
It is assumed that best practice
working methods will be adhered
to.
Minor adverse
Pollution of groundwater Moderate/ Low Risk Low risk It is assumed that best practice
working methods will be adhered to Minor beneficial
Overall Assessment Minor adverse
effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 79
11.6.7 The construction phase impact assessment within the Cherwell District
Council sub-section has been undertaken by comparing the land
contamination risks at the baseline stage to those predicted during
construction informed by the specific conditions within this sub-section.
Overall there is predicted to be a minor adverse effect as a result of the
construction phase of works. The assumptions outlined at the beginning of
the chapter are likely to reduce the risks of potential contamination to the
identified receptors to a neutral level. The potential for the
removal/remediation of any encountered contamination sources is
considered a minor beneficial effect.
11.6.8 In terms of the risks to geology as a resource within this sub-section no
local geology sites or RIGs are located within 500 m of the Project
Boundary. A band of sub-alluvial inferred sand and gravel resource is
indicated to underlie the Project to the east of Bicester to the west of
Manor Farm, underlying approximately 300 m of the Project within this
sub-section. The widening of the railway as a result of the construction
phase is considered therefore to result in a minor sterilisation of a mineral
safeguarding area. There is the potential that existing contamination
encountered during the construction phase could also be mobilised and
impact the viability of identified mineral resources; this would be
considered a minor adverse effect owing to the limited extent of mineral
resources impacted.
11.6.9 The principal ground stability issues are related to the moderate hazard
posed by shrinking or swelling clays within the Cherwell District Council
sub-section. There are also areas of compressible ground identified
associated with mapped bands of superficial Alluvium. The earthworks
design for the Project will take adequate account of these risks therefore
the impact is considered to be Neutral.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 80
Table 11.34 Construction Phase Impact Assessment for the Aylesbury Vale: Claydon/Quainton sub-section
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminated windblown
dust.
- Moderate/ Low risk
Construction related contaminants
may have the potential to impact
off-site residents; dust control
measures assumed.
Minor adverse
Exposure of off-site residents
to existing contaminants via
windblown dust.
Moderate/ Low risk Moderate/ Low risk Dust control measures assumed Neutral
Exposure of construction
workers to construction
related contaminants
- Low risk
Construction workers are
assumed to be equipped with
PPE and adhering to safe
systems of work.
Minor adverse
Exposure of construction
workers to existing
contamination disturbed
during earthworks
- Low risk
Construction workers are
assumed to be equipped with
PPE and adhering to safe
systems of work.
Minor adverse
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk
Any works undertaken in the
vicinity of the active landfill will be
coordinated with the landfill
operator. Should landfill waste be
encountered during the works
further advice must be sought.
Neutral
Exposure of construction
workers to landfill gas during
works
- Moderate risk
Where contractors are working in
areas with limited ventilation, in
close proximity to known landfills,
precautions such as the use of
LEL gas meters will be adopted.
Moderate adverse
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 81
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
The risks to built environment
receptors posed by the
creation of preferential
pathways for landfill gas
migration (explosion)
Low risk Low risk
There is the potential for the
creation of preferential pathways
for landfill gas migration during
the works.
Neutral
The risks to built environment
receptors posed by the
creation of preferential
pathways for landfill leachate
migration
Low risk Low risk
There is the potential for the
creation of preferential pathways
for landfill leachate migration
during the works. Should leachate
be encountered further advice
should be sought.
Neutral
Pollution of surface water
courses Very low risk Low risk
It is assumed that best practice
working methods will be adhered
to in terms of fuel
storage/stockpiling of soils.
Minor adverse
Pollution of groundwater Moderate risk Moderate risk
It is assumed that best practice
working methods will be adhered
to
Neutral
Overall Assessment Minor adverse effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 82
11.6.10 The construction phase impact assessment within the Aylesbury Vale:
Claydon/Quainton sub-section has been undertaken by comparing the
land contamination risks at the baseline stage to those predicted during
construction informed by the specific conditions within this sub-section.
Owing to the close proximity of contemporary and historic landfills within
this sub-section the risks of construction workers encountering landfill gas
has been given a significance of moderate adverse; appropriate
consideration of this risk will be incorporated into the planning of work.
Overall there is predicted to be a minor adverse effect during the
construction phase of works. The assumptions outlined at the beginning of
the chapter are likely to reduce the risks of potential contamination to the
identified receptors to neutral.
11.6.11 In terms of the risks to geology as a resource within this sub-section no
local geology sites or RIGs are located within 500 m of the Project
Boundary. Multiple bands of sub-alluvial inferred sand and gravel
resource are indicated beneath the Project to the east of Verney Junction,
underlying approximately 830 m of the sub-section. A band of River
Terrace deposits is indicated to the eastern extent of the sub-section and
underlying approximately 230 m of the Project. Brick clay is identified on
mineral safeguarding plans to underlie approximately 7 km of the eastern
extent of the sub-section. The widening of the railway as a result of the
construction phase, both in terms of the variety of resources impacted and
the total area underlain by identified mineral resources, is considered to
result in a moderate sterilisation of mineral resources, resulting in a
moderate adverse effect.
11.6.12 The principal ground stability issues identified within this sub-section are
related to the moderate hazard posed by shrinking or swelling clays. Two
areas along the route from Claydon Junction to Aylesbury have also been
designated a moderate risk of landslide; this appears related to the steep
topography of embankments in this area. The design of earthworks for the
Project will take adequate account of these risks, therefore the impact is
considered to be neutral.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 83
Table 11.35 Construction Phase Impact Assessment for the Aylesbury Vale: Winslow/Swanbourne sub-section
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of off-site
residents to construction
related contaminated
windblown dust.
- Moderate/ Low risk
Construction related contaminants
may have the potential to impact
off-site residents; dust control
measures assumed.
Minor adverse
Exposure of off-site
residents to existing
contaminants via
windblown dust.
Low risk Moderate / Low risk Dust control measures assumed Minor adverse
Exposure of construction
workers to construction
related contaminants
- Low risk
Construction workers are
assumed to be equipped with
PPE and adhering to safe
systems of work.
Minor adverse
Exposure of construction
workers to existing
contamination disturbed
during earthworks
- Low risk
Where contractors are working in
areas with limited ventilation, in
close proximity to known landfills,
precautions such as the use of
LEL gas meters will be adopted.
Minor adverse
Exposure of off-site
residents to landfill gas via
the creation of preferential
pathways for migration
during works
Moderate risk Moderate risk
Any works undertaken in the
vicinity of the active landfill will be
coordinated with the landfill
operator. Should landfill waste be
encountered during the works
further advice must be sought.
Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 84
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of construction
workers to landfill gas
during works
- Moderate risk
Where contractors are working in
areas with limited ventilation, in
close proximity to known landfills,
precautions such as the use of
LEL gas meters will be adopted.
Moderate adverse
The risks to built
environment receptors
posed by the creation of
preferential pathways for
landfill gas migration
(explosion)
Low risk Low risk
There is the potential for the
creation of preferential pathways
for landfill gas migration during
the works.
Neutral
The risks to built
environment receptors
posed by the creation of
preferential pathways for
landfill leachate migration
Low risk Low risk
There is the potential for the
creation of preferential pathways
for landfill leachate migration
during the works. Should leachate
be encountered further advice
should be sought.
Neutral
Pollution of surface water
courses Very low risk Low risk
It is assumed that best practice
working methods will be adhered
to in terms of fuel
storage/stockpiling of soils.
Minor adverse
Pollution of groundwater Moderate/ Low Risk Low risk
It is assumed that best practice
working methods will be adhered
to
Minor beneficial
Overall Assessment Minor adverse effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 85
11.6.13 The construction phase impact assessment within the Aylesbury Vale:
Winslow/Swanbourne sub-section has been undertaken by comparing the
land contamination risks at the baseline stage to those predicted during
construction informed by the specific conditions within this sub-section.
Overall there is predicted to be a minor adverse effect during the
construction phase of works. The effects of construction workers
encountering landfill gas as a result of works in the vicinity of historic and
contemporary landfilling have been categorised as moderate adverse;
appropriate controls for this risk will be incorporated into the planning of
work. The assumptions outlined at the beginning of the chapter are likely
to reduce the risks of potential contamination to the identified receptors to
neutral.
11.6.14 In terms of the risks to geology as a resource within this sub-section no
local geology sites or RIGs are located within 500 m of the Project
Boundary. Multiple bands of glaciofluvial sand and gravel resource are
indicated to underlie approximately 1.8 km the Project in multiple areas
surrounding Winslow. A band of sub-alluvial sand and gravel is indicated
to the north of Winslow underlying approximately 1 km of the Project. The
widening of the railway as a result of the construction phase is considered
therefore to result in a minor sterilisation of mineral safeguarding areas,
resulting in a minor adverse effect.
11.6.15 The principal ground stability issues identified within this sub-section are
related to the moderate hazard posed by shrinking or swelling clays.
Bands of alluvium have also been associated with a moderate risk of
compressible ground. The design of earthworks for the Project will take
adequate account of these risks therefore the impact is considered to be
neutral.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 86
Table 11.36 Construction Phase Impact Assessment for the Aylesbury Vale: Aylesbury sub-section
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of off-site
residents to construction
related contaminants via
windblown dust.
- Moderate/ Low risk
Construction related contaminants
may have the potential to impact
off-site residents; dust control
measures assumed.
Minor adverse
Exposure of off-site
residents to existing
contaminants via
windblown dust.
Low risk Moderate/ Low risk Dust control measures assumed Minor adverse
Exposure of construction
workers to construction
related contaminants
- Low risk
Construction workers are
assumed to be equipped with
PPE and adhering to safe
systems of work.
Minor Adverse
Exposure of construction
workers to existing
contamination disturbed
during earthworks
- Low risk
Construction workers are
assumed to be equipped with
PPE and adhering to safe
systems of work.
Minor Adverse
Exposure of off-site
residents to landfill gas via
the creation of preferential
pathways for migration
during works
Moderate Moderate
Any works undertaken in the
vicinity of the active landfill will be
coordinated with the landfill
operator. Should landfill waste be
encountered during the works
further advice must be sought.
Neutral
Exposure of construction
workers to landfill gas
during works
- Moderate risk
Where contractors are working in
areas with limited ventilation, in
close proximity to known landfills,
precautions such as the use of
Minor adverse
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 87
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
LEL gas meters will be adopted.
The risks to built
environment receptors
posed by the creation of
preferential pathways for
landfill gas migration
(explosion)
Low risk Low risk
There is the potential for the
creation of preferential pathways
for landfill gas migration during
the works.
Neutral
The risks to built
environment receptors
posed by the creation of
preferential pathways for
landfill leachate migration
Low risk Low risk
There is the potential for the
creation of preferential pathways
for landfill leachate migration
during the works. Should leachate
be encountered further advice
should be sought.
Neutral
Pollution of surface water
courses Very low risk Low risk
It is assumed that best practice
working methods will be adhered
to in terms of fuel
storage/stockpiling of soils.
Minor adverse
Pollution of groundwater Moderate
risk Low risk
It is assumed that best practice
working methods will be adhered
to
Minor beneficial
Overall Assessment Minor adverse effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 88
11.6.16 The construction phase impact assessment within the Aylesbury Vale:
Aylesbury sub-section has been undertaken by comparing the land
contamination risks at the baseline stage to those predicted during
construction, informed by the specific conditions within this sub-section.
No significant effects have been identified within this sub-section. Overall
there is predicted to be a minor adverse effect during the construction
phase of works. The assumptions outlined at the beginning of the chapter
are likely to reduce the risks of potential contamination to the identified
receptors to neutral.
11.6.17 In terms of the risks to geology as a resource within this sub-section no
local geology sites or RIGs are located within 500 m of the Project
Boundary. A band of sub-alluvial inferred sand and gravel resource is
indicated to underlie approximately 4.9 km of the Project north of
Waddesdon and Fleet Marston Farm. River terrace deposits underlie the
approximately 370 m of the Project to the north west of Quarrendon. The
widening of the railway as a result of the construction phase is considered
therefore to result in a minor sterilisation of a mineral safeguarding area,
resulting in a minor adverse effect.
11.6.18 The principal ground stability issues identified within this sub-section are
related to the moderate hazard posed by shrinking or swelling clays.
Bands of alluvium have also been associated with a moderate risk of
compressible ground. The design of earthworks for the Project will take
adequate account of these risks therefore the impact is considered to be
neutral.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 89
Table 11.37 Construction Phase Impact Assessment for the Wycombe District Council sub-section
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of off-site residents to
construction related
contaminants via windblown
dust.
- Moderate/ Low risk Construction related contaminants
may have the potential to impact off-
site residents; dust control measures
assumed.
Minor adverse
Exposure of off-site residents to
existing contaminants via
windblown dust.
Low risk Moderate/ Low risk Dust control measures assumed Minor adverse
Exposure of construction
workers to construction related
contaminants
- Low risk Construction workers are assumed to
be equipped with PPE and adhering
to safe systems of work.
Minor adverse
Exposure of construction
workers to existing
contamination disturbed during
earthworks
- Low risk Construction workers are assumed to
be equipped with PPE and adhering
to safe systems of work.
Minor adverse
Exposure of off-site residents to
landfill gas via the creation of
preferential pathways for
migration during works
Moderate risk Moderate risk Any works undertaken in the vicinity
of the active landfill will be
coordinated with the landfill operator.
Should landfill waste be encountered
during the works further advice must
be sought.
Neutral
Exposure of construction
workers to landfill gas during
works
- Moderate risk Where contractors are working in
areas with limited ventilation, in close
proximity to known landfills,
precautions such as the use of LEL
gas meters will be adopted.
Moderate adverse
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 90
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill gas migration (explosion)
Low risk Low risk There is the potential for the creation
of preferential pathways for landfill
gas migration during the works.
Neutral
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill leachate migration
Low risk Low risk There is the potential for the creation
of preferential pathways for landfill
leachate migration during the works.
Should leachate be encountered
further advice should be sought.
Neutral
Pollution of surface water
courses
Very low risk Low risk It is assumed that best practice
working methods will be adhered to
in terms of fuel storage/stockpiling of
soils.
Minor adverse
Pollution of groundwater Moderate risk Moderate risk It is assumed that best practice
working methods will be adhered to
Neutral
Overall Assessment Minor adverse
effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 91
11.6.19 The construction phase impact assessment within the Wycombe District
Council sub-section has been undertaken by comparing the land
contamination risks at the baseline stage to those predicted during
construction, informed by the specific conditions within this sub-section.
The risks of landfill gas to construction workers has been rated as
moderate owing to an identified landfill in close proximity to the Project
within Princes Risborough; however no work is proposed to take place in
this location therefore this risk is likely to be neutral. Overall there is
predicted to be a minor adverse effect during the construction phase of
works. The assumptions outlined at the beginning of the chapter are likely
to reduce the risks of potential contamination to the identified receptors to
neutral.
11.6.20 In terms of the risks to geology as a resource within this sub-section no
local geology sites or RIGs are located within 500 m of the Project
Boundary. A band of sub-alluvial inferred sand and gravel resource is
indicated to underlie the Project to the northern extent of the sub-section,
underlying approximately 150 m of the Project within this sub-section. A
narrow band of River Terrace deposits is indicated to intersect with the
Project adjacent to the northern boundary of the sub-section. An area of
low purity Chalk 93-98% is indicated to underlie approximately 3.9 km of
the Project surrounding Princes Risborough. The limited works currently
proposed within this sub-section during the construction phase is
considered therefore to result in a minor sterilisation of a mineral
resource, resulting in a minor adverse effect.
11.6.21 The principal ground stability issues identified within this sub-section are
related to bands of alluvium which have been associated with a moderate
risk of compressible ground. The design of earthworks for the Project will
take adequate account of these risks therefore the impact is considered to
be neutral.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 92
Table 11.38 Construction Phase Impact Assessment for the Milton Keynes Council sub-section
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Moderate / Low risk Construction related
contaminants may have the
potential to impact off-site
residents; dust control measures
assumed.
Minor adverse
Exposure of off-site residents
to existing contaminants via
windblown dust.
Low risk Moderate/ Low risk Dust control measures assumed Minor adverse
Exposure of construction
workers to construction related
contaminants
- Low risk Construction workers are
assumed to be equipped with
PPE and adhering to safe
systems of work.
Minor adverse
Exposure of construction
workers to existing
contamination disturbed during
earthworks
- Low risk Construction workers are
assumed to be equipped with
PPE and adhering to safe
systems of work.
Minor adverse
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk Any works undertaken in the
vicinity of the active landfill will
be coordinated with the landfill
operator. Should landfill waste
be encountered during the
works further advice must be
sought.
Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 93
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of construction
workers to landfill gas during
works
- Moderate risk Where contractors are working
in areas with limited ventilation,
in close proximity to known
landfills, precautions such as the
use of LEL gas meters will be
adopted.
Moderate adverse
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill gas migration
(explosion)
Moderate risk Low risk There is the potential for the
creation of preferential pathways
for landfill gas migration during
the works.
Minor beneficial
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill leachate migration
Moderate risk Low risk There is the potential for the
creation of preferential pathways
for landfill leachate migration
during the works. Should
leachate be encountered further
advice should be sought.
Neutral
Pollution of surface water
courses
Very low risk Low risk It is assumed that best practice
working methods will be
adhered to in terms of fuel
storage/stockpiling of soils.
Minor adverse
Pollution of groundwater Moderate risk Moderate risk It is assumed that best practice
working methods will be
adhered to
Neutral
Overall Assessment Minor adverse effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 94
11.6.22 The construction phase impact assessment within the Milton Keynes
Council sub-section has been undertaken by comparing the land
contamination risks at the baseline stage to those predicted during
construction, informed by the specific conditions within this sub-section.
Due to the long history of mineral extraction and subsequent landfilling
within this sub-section the risks of landfill gas to construction workers
have been classified as moderate adverse. Any work undertaken in the
vicinity of known landfills should incorporate control measures for the
possibility of encountering landfill gas into the risk assessment. Overall
there is predicted to be a minor adverse effect during the construction
phase of works. The assumptions outlined at the beginning of the chapter
are likely to reduce the risks of potential contamination to the identified
receptors to neutral.
11.6.23 In terms of the risks to geology as a resource within this Sub-section no
local geology sites or RIGs are located within 500 m of the Project
Boundary. A narrow band of River Terrace sand and gravel resource is
indicated to underlie the Project to the north of the former Bletchley
Brickworks site in Newton Longville. As the route branches to the north of
Bletchley station it becomes underlain by bedrock deposits of Brick Clay
with multiple historic brickworks surrounding Milton Keynes. As the route
extends to the east of Bletchley it is underlain by River terrace deposits
and Brick Clay surrounding Fenny Stratford. Further to the east the former
Station Brick and tile works and the Woburn Sands brickworks historic
clay extraction sites have been identified. There is the potential for
extraction of further mineral reserves in this study area in the future,
however given the narrow Project Area and existing railway infrastructure,
it is unlikely that significant mineral resource sterilisation will occur.
11.6.24 The principal ground stability issues identified within this sub-section are
related to the moderate hazard posed by shrinking or swelling clays.
Bands of alluvium have also been associated with a moderate risk of
compressible ground. The design of earthworks for the Project will take
account of these risks and therefore the impact is considered to be
neutral.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 95
Table 11.39 Construction Phase Impact Assessment for the Central Bedfordshire Council sub-section
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Low risk
Construction related
contaminants may have the
potential to impact off-site
residents; dust control measures
assumed.
Minor adverse
Exposure of off-site residents
to existing contaminants via
windblown dust.
Low risk Low risk Dust control measures assumed Neutral
Exposure of construction
workers to construction
related contaminants
- Low risk
Construction workers are
assumed to be equipped with
PPE and adhering to safe
systems of work.
Minor adverse
Exposure of construction
workers to existing
contamination disturbed
during earthworks
- Low risk
Construction workers are
assumed to be equipped with
PPE and adhering to safe
systems of work.
Minor adverse
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk
Any works undertaken in the
vicinity of the active landfill will
be coordinated with the landfill
operator. Should landfill waste
be encountered during the
works further advice must be
sought.
Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 96
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of construction
workers to landfill gas during
works
- Moderate risk
Where contractors are working
in areas with limited ventilation,
in close proximity to known
landfills, precautions such as the
use of LEL gas meters will be
adopted.
Moderate adverse
The risks to built environment
receptors posed by the
creation of preferential
pathways for landfill gas
migration (explosion)
Low risk Low risk
There is the potential for the
creation of preferential pathways
for landfill gas migration during
the works.
Neutral
The risks to built environment
receptors posed by the
creation of preferential
pathways for landfill leachate
migration
Low risk Low risk
There is the potential for the
creation of preferential pathways
for landfill leachate migration
during the works. Should
leachate be encountered further
advice should be sought.
Neutral
Pollution of surface water
courses Very low risk Low risk
It is assumed that best practice
working methods will be
adhered to in terms of fuel
storage/stockpiling of soils.
Minor adverse
Pollution of groundwater Low risk Moderate risk
It is assumed that best practice
working methods will be
adhered to
Minor adverse
Overall Assessment Minor adverse effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 97
11.6.25 The construction phase impact assessment within the Central
Bedfordshire Council sub-section has been undertaken by comparing the
land contamination risks at the baseline stage to those predicted during
construction, informed by the specific conditions within this sub-section.
Owing to the history of mineral extraction and subsequent landfilling in the
vicinity of the Project the effects of exposure to landfill gases on
construction workers has been classified as moderate adverse. Any works
in the vicinity of the Project must incorporate considerations and controls
appropriate to the encounter of landfilled waste. Overall there is predicted
to be a minor adverse effect during the construction phase of works. The
assumptions outlined at the beginning of the chapter are likely to reduce
the risks of potential contamination to the identified receptors to neutral.
11.6.26 In terms of the risks to geology as a resource within this sub-section no
local geology sites or RIGs are located within 500 m of the Project
Boundary. An outcrop of the Lower Oxford Clay surrounding historic clay
pits adjacent to the Quest clay pit have been identified adjacent to the
Project. The Woburn Sands formation intersects with the Project Area to
the north of Aspley Guise. The limited proposed work within this sub-
section in the construction phase is considered to result in a neutral effect
on geology as a resource.
11.6.27 The principal ground stability issues identified within this sub-section are
related to the moderate hazard posed by shrinking or swelling clays.
Bands of alluvium have also been associated with a moderate risk of
compressible ground. An area centrally has been designated as a
moderate landslide risk; this appears to be associated with an area of
unmapped superficial deposits and regional topography. The design of
earthworks for the Project will take adequate account of these risks
therefore the impact is considered to be neutral.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 98
Table 11.40 Construction Phase Impact Assessment for the Bedford Borough Council sub-section
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
Exposure of off-site
residents to construction
related contaminants via
windblown dust.
- Moderate/ Low risk
Construction related
contaminants may have
the potential to impact
off-site residents; dust
control measures
assumed.
Minor adverse
Exposure of off-site
residents to existing
contaminants via
windblown dust.
Low risk Low risk Dust control measures
assumed Neutral
Exposure of construction
workers to construction
related contaminants
- Low risk
Construction workers
are assumed to be
equipped with PPE and
adhering to safe
systems of work.
Minor adverse
Exposure of construction
workers to existing
contamination disturbed
during earthworks
- Low risk
Construction workers
are assumed to be
equipped with PPE and
adhering to safe
systems of work.
Minor adverse
Exposure of off-site
residents to landfill gas via
the creation of preferential
pathways for migration
during works
Moderate risk Moderate risk
Any works undertaken in
the vicinity of the active
landfill will be
coordinated with the
landfill operator. Should
landfill waste be
encountered during the
Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 99
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
works further advice
must be sought.
Exposure of construction
workers to landfill gas
during works
- Moderate risk
Where contractors are
working in areas with
limited ventilation, in
close proximity to known
landfills, precautions
such as the use of LEL
gas meters will be
adopted.
Moderate adverse
The risks to built
environment receptors
posed by the creation of
preferential pathways for
landfill gas migration
(explosion)
- Low risk
There is the potential for
the creation of
preferential pathways for
landfill gas migration
during the works.
Minor adverse
The risks to built
environment receptors
posed by the creation of
preferential pathways for
landfill leachate migration
Low risk Low risk
There is the potential for
the creation of
preferential pathways for
landfill leachate
migration during the
works. Should leachate
be encountered further
advice should be
sought.
Neutral
Pollution of surface water Very low risk Low risk It is assumed that best Minor adverse
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 100
Potential linkage Baseline (current) risk assessment
Construction stage risk assessment
Comment Significance of effect
courses practice working
methods will be adhered
to in terms of fuel
storage/stockpiling of
soils.
Pollution of groundwater Low/ Moderate Risk Low risk
It is assumed that best
practice working
methods will be adhered
to
Minor beneficial
Overall Assessment Minor adverse effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 101
11.6.28 The construction phase impact assessment within the Bedford Borough
Council sub-section has been undertaken by comparing the land
contamination risks at the baseline stage to those predicted during
construction, informed by the specific conditions within this sub-section.
The risks of landfill gas encounter to construction workers has been
assessed as a moderate adverse effect. The limited works proposed
currently within this sub-section would likely mitigate this potential effect to
neutral. Overall there is predicted to be a minor adverse effect during the
construction phase of works. The assumptions outlined at the beginning of
the chapter are likely to reduce the risks of potential contamination to the
identified receptors to neutral.
11.6.29 In terms of the risks to geology as a resource within this sub-section no
local geology sites or RIGs are located within 500 m of the Project
Boundary. An outcrop area of Lower Oxford Clay surrounding historic clay
pits adjacent to Kempston Hardwick further to the north of Elstow the
route is underlain by river gravel resources. Owing to the limited works
currently proposed within this sub-section the effect on minerals as a
resource is considered to be neutral.
11.6.30 The principal ground stability issues identified within this sub-section are
related to the moderate hazard posed by shrinking or swelling clays.
Bands of alluvium have also been associated with a moderate risk of
compressible ground. The design of earthworks for the Project will take
adequate account of these risks therefore the impact is considered to be
neutral.
Construction Phase Conclusions
11.6.31 The construction phase of works across the sub-sections is considered to
result in neutral to minor adverse effects to controlled waters, off-site
human health and built environment receptors. The exception to this are
the potential moderate adverse effects identified associated with
construction workers being impacted by exposure to landfill gas.
Insufficient information currently exists to adequately assess and mitigate
these risks; additional intrusive ground investigation will be undertaken in
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 102
order to characterise the risk and identify appropriate worker protection
measures (if required).
11.6.32 No RIGs or locally important geology sites have been identified within 500
m of the Project Boundary. There are instances of potential mineral
sterilisation as a result of land take required by the Project, particularly
surrounding Milton Keynes. However, the extent of additional land take
when compared to the baseline is considered minor owing to the
presence of the existing railway overlying much of these mineral
resources.
11.6.33 The principal ground stability issues identified across the Project is related
to the moderate hazard posed by shrinking or swelling clays associated
with the various members of the Oxford Clay formation. The earthworks
design for the Project will take this risk into consideration.
Operation
11.6.34 The following tables present the CSM findings for the operation phase.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 103
Table 11.41 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Cherwell District Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Residual
contaminants within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for maintenance
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of windblown dust.
Off-site residents of adjacent
properties.
Recreational users of land within
and adjacent to the Project Area
Mild Unlikely Very low risk
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of vapours.
Maintenance workers Minor Unlikely Very low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for maintenance
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways e.g. newly-created
service runs.
Superficial Secondary A aquifer
(Alluvial deposits)
Launton Brook and Langford
Brook
Minor Unlikely Very low risk
Geological hazards Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 104
Source of risk Pathway / action Receptor Consequence Probability Risk
(ground stability) Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low
risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 105
Table 11.42 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Claydon/Quainton sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Residual
contaminants within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of windblown dust.
Off-site residents of adjacent
properties.
Recreational users of land within
and adjacent to the Project Area
Mild Unlikely Very low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of vapours.
Maintenance workers Minor Unlikely Very low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along
preferential pathways e.g.
newly-created service runs.
Multiple surface water courses as
listed in Table 11.14.
Minor Unlikely Very low risk
Superficial Secondary A aquifer
(Alluvium & River Terrace Deposits)
Minor Low likelihood Very low risk
Infill material
associated with the
Migration of ground gas
through permeable ground/
Built environment receptors:
Buildings, subsurface structures
Mild Low likelihood Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 106
Source of risk Pathway / action Receptor Consequence Probability Risk
former Calvert clay
pits/brick works
utility corridors/ cracks in
floor slabs/ service entry
points with potential
accumulation to explosive
atmospheres
including utilities surrounding the
Project Area.
Maintenance Workers Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate
into the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low
risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low
risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 107
Table 11.43 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Winslow/Swanbourne sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Residual contaminants
within Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants introduced
to the Project, e.g. fuel
and oils for construction
plant and equipment.
Dermal contact/
ingestion/ inhalation of
contaminated dust and
soil.
Inhalation of windblown
dust.
Off-site residents of adjacent
properties.
Recreational users of land within
and adjacent to the Project Area
Mild Unlikely Very low risk
Dermal contact/
ingestion/ inhalation of
contaminated dust and
soil.
Inhalation of vapours.
Maintenance workers Minor Unlikely Very low risk
Contaminants introduced
to the Project, e.g. fuel
and oils for construction
plant and equipment.
Increase in suspended
silts into surface run-off
Surface run-off
Migration of
contaminants through
granular or fractured
materials
Leaching / migration of
contaminants through
Made Ground and along
preferential pathways
e.g. newly-created
service runs.
Horwood Brook
Unnamed minor watercourse to the
east of Whaddon Road.
Superficial Secondary A aquifer
Minor Low likelihood Very low risk
Buried waste of unknown Migration of ground gas Built environment receptors: Mild Low likelihood Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 108
Source of risk Pathway / action Receptor Consequence Probability Risk
provenance at the active
landfill at Newton
Longville Project and the
surrounding historic
landfills.
through permeable
ground/ utility corridors/
cracks in floor slabs/
service entry points with
potential accumulation
to explosive
atmospheres
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Maintenance workers Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill
leachate into the Project
Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low Moderate / low
risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Low Moderate / low
risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 109
Table 11.44 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Aylesbury Vale: Aylesbury sub-section
Source of risk Pathway / action Receptor Consequence
Probability Risk
Residual
contaminants within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Off-site residents of adjacent
properties.
Mild Unlikely Very low risk
Dermal contact/ ingestion/
inhalation of contaminated dust
and soil.
Inhalation of vapours.
Construction/Maintenance
workers
Minor Unlikely Very low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants through
granular or fractured materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways e.g. newly-created
service runs.
Fleet Marston Brook
the River Thame
Bear Brook
Coldharbour Way Ditch,
California Brook
Stoke Brook
Minor Low likelihood Very low risk
Superficial Secondary A aquifer
Bedrock Principal & Secondary A
aquifers
Medium Low likelihood Moderate / low
risk
Buried waste of
unknown provenance
adjacent to the Project
Migration of ground gas through
permeable ground/ utility
corridors/ cracks in floor slabs/
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Mild Low likelihood Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 110
Source of risk Pathway / action Receptor Consequence
Probability Risk
Area including
Channel Infill
associated with the
River Thame.
service entry points with potential
accumulation to explosive
atmospheres
Project Area.
Maintenance workers Severe Low likelihood Moderate risk
Off-site human health receptors in
properties adjacent to the Project
Severe Low likelihood Moderate risk
Migration of landfill leachate into
the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low
risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low
risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 111
Table 11.45 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Wycombe District Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Residual
contaminants within
Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Off-site residents of adjacent
properties.
Mild Low likelihood Very low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of vapours.
Maintenance workers Minor Low likelihood Very low risk
Contaminants
introduced to the
Project, e.g. fuel and
oils for construction
plant and equipment.
Increase in suspended
silts into surface run-
off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along preferential
pathways e.g. newly-created
service runs.
Terrick Brook and Scotsgrove
Brook
Minor Low likelihood Very low risk
Superficial Secondary A & Principal
Bedrock aquifers
Medium Low likelihood Moderate / low
risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 112
Source of risk Pathway / action Receptor Consequence Probability Risk
Buried waste of
unknown provenance
adjacent to the Project
Area associated with
historic landfilling.
Migration of ground gas
through permeable ground/
utility corridors/ cracks in floor
slabs/ service entry points with
potential accumulation to
explosive atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
Maintenance workers Severe Unlikely Moderate/low
risk
Off-site human health receptors in
properties adjacent to the Project
Area
Severe Unlikely Moderate/low
risk
Migration of landfill leachate
into the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low
risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 113
Table 11.46 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Milton Keynes Council sub-section
Source of risk Pathway / action Receptor Consequence
Probability Risk
Residual contaminants
within Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants introduced
to the Project, e.g. fuel
and oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Off-site residents of adjacent
properties.
Mild Unlikely Very low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of vapours.
Maintenance workers Minor Unlikely Very low risk
Contaminants introduced
to the Project, e.g. fuel
and oils for construction
plant and equipment.
Increase in suspended
silts into surface run-off
Surface run-off
Migration of contaminants
through granular or
fractured materials
Leaching / migration of
contaminants through
Made Ground and along
preferential pathways e.g.
newly-created service runs.
The River Great Ouse, the Blue
Lagoon LNR, Caldecotte Lake and
the Grand Union Canal
Minor Unlikely Very low risk
Superficial & Bedrock Secondary A
aquifers
Medium Low likelihood Moderate / low
risk
Buried waste of unknown
provenance at the active
landfill at Newton
Longville Project and
Migration of ground gas
through permeable ground/
utility corridors/ cracks in
floor slabs/ service entry
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 114
Source of risk Pathway / action Receptor Consequence
Probability Risk
surrounding historic
landfills.
points with potential
accumulation to explosive
atmospheres
Maintenance workers Severe Unlikely Moderate/low
risk
Off-site human health receptors in
properties adjacent to the Project
Area
Severe Unlikely Moderate/low
risk
Migration of landfill
leachate into the Project
Area
Subsurface infrastructure/foundations Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low
risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 115
Table 11.47 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Central Bedfordshire Council sub-section
Source of risk Pathway / action Receptor Consequence
Probability Risk
Residual contaminants
within Made Ground of
unknown provenance
associated with the
historical uses of the
land surrounding the
Project Area.
Contaminants introduced
to the Project, e.g. fuel
and oils for construction
plant and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Off-site residents of adjacent
properties.
Mild Unlikely Very low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of vapours.
Maintenance workers Mild Unlikely Very low risk
Contaminants introduced
to the Project, e.g. fuel
and oils for construction
plant and equipment.
Increase in suspended
silts into surface run-off
Surface run-off
Migration of contaminants
through granular or fractured
materials
Leaching / migration of
contaminants through Made
Ground and along
preferential pathways e.g.
newly-created service runs.
Controlled waters: The Broughton
Brook (ordinary watercourse)
Minor Low likelihood Very low risk
Superficial Secondary A aquifer Mild Low likelihood Low Risk
Buried waste of unknown
provenance within the
surrounding historic
landfills.
Migration of ground gas
through permeable ground/
utility corridors/ cracks in
floor slabs/ service entry
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Mild Low likelihood Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 116
Source of risk Pathway / action Receptor Consequence
Probability Risk
points with potential
accumulation to explosive
atmospheres
Exposure of maintenance workers
to landfill gas.
Severe Unlikely Moderate/low
risk
Off-site human health receptors in
properties adjacent to the Project
Area
Severe Unlikely Moderate risk
Migration of landfill leachate
into the Project Area
Subsurface
infrastructure/foundations
Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low
risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 117
Table 11.48 Operational Phase Conceptual Site Model Findings: Potential Contaminant Linkages Associated with the Project within the Bedford Borough Council sub-section
Source of risk Pathway / action Receptor Consequence Probability Risk
Residual contaminants
Made Ground of unknown
provenance associated
with the historical uses of
the land surrounding the
Project Area.
Contaminants introduced
to the Project, e.g. fuel and
oils for construction plant
and equipment.
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Off-site residents of adjacent
properties.
Mild Unlikely Very low risk
Dermal contact/ ingestion/
inhalation of contaminated
dust and soil.
Inhalation of vapours.
Maintenance workers Minor Unlikely Very low risk
Contaminants introduced
to the Project, e.g. fuel and
oils for construction plant
and equipment.
Increase in suspended
silts into surface run-off
Surface run-off
Migration of contaminants
through granular or
fractured materials
Leaching / migration of
contaminants through
Made Ground and along
preferential pathways e.g.
newly-created service
runs.
Groundwater (SPZ): Superficial
Secondary A and bedrock Principal
aquifers
Numerous water bodies within the
sub-section which cross the Project
Area.
The River Ouse and an unnamed
river.
Medium Low likelihood Moderate/low
risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 118
Source of risk Pathway / action Receptor Consequence Probability Risk
Buried waste of unknown
provenance within and
surrounding the historic
landfills.
Migration of ground gas
through permeable
ground/ utility corridors/
cracks in floor slabs/
service entry points with
potential accumulation to
explosive atmospheres
Built environment receptors:
Buildings, subsurface structures
including utilities surrounding the
Project Area.
Severe Unlikely Moderate/Low
risk
Maintenance workers Severe Unlikely Moderate/low
risk
Off-site human health receptors in
properties adjacent to the Project
Area
Severe Unlikely Moderate/low
risk
Migration of landfill
leachate into the Project
Area
Subsurface infrastructure/foundations Mild Low likelihood Low risk
Geological hazards
(ground stability)
Collapsible ground Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Compressible ground Existing and new, on- and off-site
structures
Medium Low likelihood Moderate / low
risk
Ground dissolution Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Landslide Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Running sand Existing and new, on- and off-site
structures
Medium Unlikely Low risk
Shrinking / swelling clay Existing and new, on- and off-site
structures
Medium Unlikely Low risk
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 120
Operation Phase Impact Assessment
11.6.35 The operational phase impact assessment has been undertaken by
comparing the land contamination risks at the baseline stage to those
predicted during operation for each sub-section. This is summarised by
sub-section within Table 11.49 to Table 11.56. As during the construction
phase several assumptions have been incorporated regarding the finished
condition of the Project:
Contaminated arisings from construction will be appropriately managed and removed from the Project Area following construction;
All potentially contaminative construction-related materials (fuels / chemicals / paints / stockpiled soils) would be removed from the Project Area;
Bare soils will be re-vegetated as part of the Project completion; any contamination encountered will be bunded and sealed / sheeted prior to removal from site
Detailed control measures will be included in risk assessments. Primary control will be to prevent exposure by careful selection of materials, safety / COSHH briefing will form part of task briefings and suitable PPE provided;
Bunds, cut-off ditches, settlement lagoons, segregation of refuelling etc. will be employed to protect surface and groundwater receptors from e.g. spillages and silt;
Material will be subject to contamination identification and treatment prior to commencement; site workers will be briefed on visual signs of contamination; and
Construction work areas within the Project Area will be fenced preventing access.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 121
Table 11.49 Operational Phase Impact Assessment for the Cherwell District Council sub-section
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Very low risk See above assumptions. Neutral
Exposure of off-site residents
to residual contaminants via
windblown dust.
Moderate / Low risk Very low risk See above assumptions. Neutral
Exposure of construction
workers to construction related
contaminants
- Very low risk See above assumptions. Neutral
Exposure of construction
workers to residual
contamination disturbed during
earthworks
- Very low risk See above assumptions Neutral
Pollution of surface water
courses
Very low risk Very low risk See above assumptions. Neutral
Pollution of groundwater Moderate Very low risk See above assumptions Minor beneficial
Overall Assessment Neutral effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 122
Table 11.50 Operational Phase Impact Assessment for the Aylesbury Vale: Claydon/Quainton sub-section
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to residual contaminants via
windblown dust.
Moderate / Low Very low risk See above assumptions Minor beneficial
Exposure of construction
workers to construction related
contaminants
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk See above assumptions Neutral
Exposure of construction /
maintenance workers to landfill
gas during works
- Moderate risk See above assumptions Neutral
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill gas migration
(explosion)
Low risk Low risk See above assumptions Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 123
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill leachate migration
Low risk Low risk See above assumptions Neutral
Exposure of construction
workers to residual
contamination disturbed during
earthworks
- Very low risk See above assumptions Neutral
Pollution of surface water
courses
Very low risk Very low risk See above assumptions Neutral
Pollution of groundwater Moderate Very low risk See above assumptions Minor beneficial
Overall Assessment Neutral effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 124
Table 11.51 Operational Phase Impact Assessment for the Aylesbury Vale: Winslow/Swanbourne sub-section
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to residual contaminants via
windblown dust.
Low risk Very low risk See above assumptions Minor beneficial
Exposure of construction
workers to construction related
contaminants
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk See above assumptions Neutral
Exposure of construction
workers to landfill gas during
works
- Moderate risk See above assumptions Neutral
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill gas migration
(explosion)
Low risk Low risk See above assumptions Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 125
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill leachate migration
Low risk Low risk See above assumptions Neutral
Exposure of construction
workers to residual
contamination disturbed during
earthworks
- Very low risk See above assumptions Neutral
Pollution of surface water
courses
Very low risk Very low risk See above assumptions Neutral
Pollution of groundwater Low Very low risk See above assumptions Minor beneficial
Overall Assessment Neutral effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 126
Table 11.52 Operational Phase Impact Assessment for the Aylesbury Vale: Aylesbury sub-section
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to residual contaminants via
windblown dust.
Low risk Very low risk See above assumptions Minor beneficial
Exposure of construction
workers to construction related
contaminants
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk See above assumptions Neutral
Exposure of construction
workers to landfill gas during
works
- Moderate risk See above assumptions Neutral
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill gas migration
(explosion)
Low risk Low risk See above assumptions Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 127
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill leachate migration
Low risk Low risk See above assumptions. Neutral
Exposure of construction
workers to residual
contamination disturbed during
earthworks
- Very low risk See above assumptions Neutral
Pollution of surface water
courses
Very low risk Very low risk See above assumptions Neutral
Pollution of groundwater Moderate Very low risk See above assumptions Neutral
Overall Assessment Neutral effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 128
Table 11.53 Operational Phase Impact Assessment for the Wycombe District Council sub-section
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to residual contaminants via
windblown dust.
Low risk Very low risk See above assumptions Neutral
Exposure of construction
workers to construction related
contaminants
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk See above assumptions Neutral
Exposure of construction
workers to landfill gas during
works
- Moderate risk See above assumptions Neutral
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill gas migration
(explosion)
Low risk Low risk See above assumptions Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 129
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill leachate migration
Low risk Low risk See above assumptions Neutral
Exposure of construction
workers to residual
contamination disturbed during
earthworks
- Very low risk See above assumptions Neutral
Pollution of surface water
courses
Very low risk Very low risk See above assumptions Neutral
Pollution of groundwater Moderate Very low risk See above assumptions Minor beneficial
Overall Assessment Neutral effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 130
Table 11.54 Operational Phase Impact Assessment for the Milton Keynes Council sub-section
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to residual contaminants via
windblown dust.
Low risk Very low risk See above assumptions Neutral
Exposure of construction
workers to construction related
contaminants
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk See above assumptions Neutral
Exposure of construction
workers to landfill gas during
works
- Moderate risk See above assumptions Neutral
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill gas migration
(explosion)
Low risk Low risk See above assumptions Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 131
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill leachate migration
Moderate risk Low risk See above assumptions Neutral
Exposure of construction
workers to residual
contamination disturbed during
earthworks
- Very low risk See above assumptions Neutral
Pollution of surface water
courses
Very low risk Very low risk See above assumptions Neutral
Pollution of groundwater Moderate Very low risk See above assumptions Minor beneficial
Overall Assessment Neutral effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 132
Table 11.55 Operational Phase Impact Assessment for the Central Bedfordshire Council sub-section
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to residual contaminants via
windblown dust.
Low risk Very low risk See above assumptions Minor beneficial
Exposure of construction
workers to construction related
contaminants
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk See above assumptions Neutral
Exposure of construction
workers to landfill gas during
works
- Moderate risk See above assumptions Neutral
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill gas migration
(explosion)
Low risk Low risk See above assumptions Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 133
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill leachate migration
Low risk Low risk See above assumptions Neutral
Exposure of construction
workers to residual
contamination disturbed during
earthworks
- Very low risk See above assumptions Neutral
Pollution of surface water
courses
Very low risk Very low risk See above assumptions Neutral
Pollution of groundwater Low risk Very low risk See above assumptions Minor beneficial
Overall Assessment Neutral effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 134
Table 11.56 Operational Phase Impact Assessment for the Bedford Borough Council sub-section
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
Exposure of off-site residents
to construction related
contaminants via windblown
dust.
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to residual contaminants via
windblown dust.
Low risk Very low risk See above assumptions Neutral
Exposure of construction
workers to construction related
contaminants
- Very low risk See above assumptions Neutral
Exposure of off-site residents
to landfill gas via the creation
of preferential pathways for
migration during works
Moderate risk Moderate risk See above assumptions Neutral
Exposure of construction
workers to landfill gas during
works
- Moderate risk See above assumptions Neutral
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill gas migration
(explosion)
Low risk Low risk See above assumptions Neutral
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 135
Potential linkage Baseline (current) risk assessment
Operational stage risk assessment
Comment Significance of effect
The risks to built environment
receptors posed by the creation
of preferential pathways for
landfill leachate migration
Low risk Low risk See above assumptions Neutral
Exposure of construction
workers to residual
contamination disturbed during
earthworks
- Very low risk See above assumptions Neutral
Pollution of surface water
courses
Very low risk Very low risk See above assumptions Neutral
Pollution of groundwater Very low risk Very low risk See above assumptions Neutral
Overall Assessment Neutral effect
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 136
Operational Phase Conclusion
Mineral Resources (a)
11.6.36 The operational phase impact assessment has not identified any potential
significant loss of mineral resource on completion.
Physical Effects (Stability) (b)
11.6.37 Design of the Project engineering will take in to account the particular
ground stability conditions, therefore resulting in no anticipated impact at
operation stage.
Potential for Contamination introduction / mobilisation (c)
11.6.38 The operational phase impact assessment has been undertaken by
comparing the land contamination risks at the baseline stage to those
predicted during the operation of the Project. It is anticipated that there
will be no change to the baseline condition as a result of the development
as a result of embedded mitigation measures incorporated into the
Project. The mitigation measures in isolation may not however be
sufficient to lower the risk levels in every instance as (assuming the worst
case) contamination will remain and some pathways will still exist.
11.6.39 With mitigation incorporated into the design of the Project, a minor
beneficial effect is anticipated associated with the removal/remediation of
encountered on-site contamination as well as improvements to the Project
drainage systems. The anticipated minor beneficial and neutral effects
are considered to be not significant.
Waste soils and material re-use (e)
11.6.40 The conclusions for this part of the assessment will be presented in the
final ES.
11.7 Mitigation
11.7.1 Given the incorporated mitigation outlined in Section 11.3 and that the
ground conditions and contamination effects are assessed as neutral and
not significant, no further mitigation is required.
The Network Rail (East West Rail Western Section Phase 2) Order
Draft Environmental Statement
Volume 2 Chapter 11 Page 137
11.8 Residual Effects
11.8.1 With no further mitigation considered to be required the residual effects for
construction and operation of the Project are as reported above.