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5
ENVIRONMENTAL IMPACT ASSESSMENT METHODOLOGY
5.1
The EIA process
5.1.1
The main aims of Environmental Impact Assessment (“EIA”) are to inform
decision-makers of the environmental effects of the Scheme on people
and the environment, and to minimise the adverse effects of a project,
within engineering and other constraints.
5.1.2
EIA is an iterative process, which continues and develops in conjunction
with the design of the Scheme.
5.1.3
In general terms, the main stages in the assessment prior to an application
are as follows:
a)
Data Review - draw together and review available data;
b)
Screening - determine the need for EIA;
c)
Scoping - identify significant issues, determine the subject matter of
the assessment and the methodologies for undertaking the
assessment;
d)
Baseline Surveys - undertake surveys and monitoring to identify
existing environmental conditions;
e)
Consultation - provide information to consultees and the public
about the Scheme so that parties can make informed contributions
to the development of the Scheme and EIA process, and take
account of issues raised by consultees;
f)
Assessment and Iteration - assess the likely effects of the Scheme
(including alternatives) on people, communities and the
environment; identify the need for mitigation through improved
design and environmental management during construction and
operation; and re-assess the residual effects of the mitigated
development; and
g)
Preparation of an Environmental Statement (“ES”).
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5.2
Design guidance
5.2.1
The development and design of major highway projects is addressed by
guidance and standards set out in the Design Manual for Roads and
Bridges (“DMRB”). Volume 11 of DMRB provides guidance on the EIA
methodologies for highway projects, while environmental design guidance
is provided in Volume 10 (Ref 5-1). Where DMRB does not provide topic
specific guidance, alternative sources of guidance have been used in the
assessments undertaken for the Scheme. DMRB is supplemented by a
number of Interim Advice Notes (“IANs”) that provide up-to-date and
detailed guidance in relation to certain environmental topic assessments.
DMRB and IANs are published by the Department for Transport (“DfT”)
and the Highways Agency (“the Agency”) respectively.
5.2.2
DMRB Volume 11, Section 2, Part 1, ‘General Principles and Guidance on
Environmental Impact Assessment’ outlines the approach to assessment
that may be relevant, depending upon the potential environmental effects
and the stage of the project. The assessment levels are: scoping, simple
and detailed. These levels are not intended to be sequential, but
consequential on the findings at each stage. A different level of
assessment may be appropriate for each environmental topic.
5.3
Screening and scoping
5.3.1
As noted in paragraph 1.4.2 of chapter 1, the Scheme is a Schedule 2
development, which may have significant adverse effects on the
environment, and so is subject to EIA. Consequently, the Agency has
prepared this ES in accordance with DMRB and the Infrastructure
Planning (Environmental Impact Assessment) Regulations 2009 (“EIA
Regulations”).
5.3.2
In accordance with Regulation 8 of the EIA Regulations, the Agency
requested an opinion from the Secretary of State on the scope of the
information to be included in the ES for the Scheme. To inform the
Secretary of State’s Scoping Opinion, a Scoping Report was submitted by
the Agency outlining the intended scope of each environmental topic. The
Scoping Report identified that the Scheme could have environmental
effects on the following topic areas:
a)
Air Quality;
b)
Cultural Heritage;
c)
Landscape;
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d)
Nature Conservation;
e)
Geology and Soils;
f)
Materials and Waste;
g)
Noise and Vibration;
h)
Effects on All Travellers;
i)
Community and Private Assets;
j)
Road Drainage and the Water Environment; and
k)
Cumulative Effects.
5.3.3
The Scoping Report provided an outline approach for the identification of
potentially adverse and beneficial effects for each of the identified topics.
5.3.4
In formulating its response, the Planning Inspectorate (“Inspectorate”), on
behalf of the Secretary of State, consulted with nearly 150 stakeholders on
the Scoping Report and incorporated those stakeholders' comments on
the scope of the EIA into the Scoping Opinion. Drawing upon the Scoping
Opinion published by the Inspectorate on 19 September 2014, and the
Agency's on-going surveys and assessment work, this ES presents an upto-date assessment of the potentially significant environmental effects of
the Scheme. The approach taken to address each of the comments made
in the Inspectorate’s Scoping Opinion is set out in Appendix 5.1 of
Document Reference 6.3 (ES Appendices). The Agency's consultation of
the relevant Statutory Nature Conservation Bodies and other bodies
undertaken as part of the EIA is described in the Consultation Report.
5.3.5
In addition to the topics set out above, the Scoping Report considered the
need for a Health Impact Assessment. The Government’s National Policy
Statement for National Networks ("NN NPS") notes that national road
networks have the potential to affect the health, well-being and quality of
life of the population (see paragraph 4.81 of the NN NPS). This can be in a
variety of ways, for example:
a)
direct effects on health and wellbeing through changes in noise and
air pollution, water quality and climate change;
b)
lifestyle changes, such as encouraging travel by means other than
private car, for example encouraging walking and cycling;
c)
effects on the local economy by changing access to employment;
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d)
effects on access to key services, particularly access to health
facilities;
e)
changes to the built environment to promote exercise through a
healthy environment; and
f)
effects on accessibility to the countryside and open spaces.
5.3.6
The potential effects of the Scheme on pedestrians and cyclists in terms of
human health effects are covered in chapter 13 Effect on All Travellers.
Potential human health effects are also referred to in chapter 6 Air Quality
and chapter 12 Noise and Vibration.
5.4
Study areas
5.4.1
There is no single study area which is applicable to all topic areas in this
ES. Instead, the study areas for each topic vary according to the
environmental resource potentially affected. The individual study areas for
each environmental topic are defined in chapters 6 to 15. These are based
on the geographical scope of the potential effects relevant to the topic, and
the information required to assess the effects, as well as topic specific
guidance provided in DMRB and other best practice guidance and
consultation with stakeholders.
5.4.2
A 1km study area, from the centreline of the Scheme (in most locations,
the central reserve) between junctions 3 and 12, is shown on all drawings
presented in Volume 2. This generally represents the widest study area
used by any of the disciplines. However, where the study area has been
extended beyond 1km to include off-line areas for traffic management or
proposed construction compounds, a buffer of 250m surrounding the offline areas has been used. In the professional opinion of the experts
carrying out the various assessments, this is considered to represent the
likely area within which potential significant effects could occur.
5.5
Baseline data
5.5.1
Establishing the baseline environmental conditions (i.e. the environment
without the Scheme) is a necessary starting point for any assessment of
potential change as a result of the Scheme. The existing conditions for the
study area have been identified by desk-based study and/or survey, or
calculated by modelling to allow the assessment of changes that would be
caused by the Scheme.
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5.5.2
For the assessment of environmental effects, the baseline needs to reflect
the conditions that would exist in the absence of the Scheme, at:
a)
the time that construction is expected to start, for effects arising
from construction (the start of construction for this Scheme being
September 2016);
b)
the time that the Scheme is expected to open to traffic, for impacts
arising from its operation on opening (the Opening Year for this
Scheme being 2022); and
c)
a period after the Scheme opens for traffic (usually taken at 15
years after opening), for impacts arising from its operation in the
longer term (the Design Year for this Scheme being 2037).
5.5.3
Therefore, it is necessary to predict the changes that would occur in the
absence of the Scheme. This includes the consideration of trends such as
traffic growth, and identification of developments that are likely to be
implemented (i.e. committed developments) before the Scheme is
constructed. In this assessment, this is referred to as the ‘future baseline’.
5.5.4
The description of the baseline and future baseline conditions has
identified receptors that may be affected by the Scheme and also their
‘value’ and/or ‘sensitivity’ to potential change. Receptors may be a
physical resource (e.g. a water body or a habitat type), flora/fauna, or a
user group (e.g. local residents or recreational users of an area). Some
receptors will be more sensitive to particular environmental impacts than
others, or be considered more valuable.
5.6
Assessment of effects
Defining assessment years and scenarios
5.6.1
The assessment of effects compares a scenario with the Scheme against
one without the Scheme over time. The absence and presence of the
Scheme are referred to as the ‘Do Minimum’ and ‘Do Something’
scenarios respectively. The ‘Do Minimum’ scenario represents the future
baseline with minimal interventions and without new infrastructure,
particularly the Scheme or alternatives. The ‘Do Something’ scenario
represents the situation if the Scheme is progressed.
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5.6.2
Depending on the topic, the effects are assessed for the ‘Do Minimum’ and
‘Do Something’ scenarios in the baseline year and a future assessment
year, or a series of future assessment years. For example, assessments
might be undertaken 15 years after opening, or the worst year in the first
15 years of operation.
5.6.3
This ES sets out the assessment of the construction and operation effects
of the Scheme. The Scheme has been, and will continue to be, designed
to maximise the scope for materials re-use in the event of
decommissioning of its components, as well as considering the design life
and maintenance requirements of the Scheme. In view of the long designlife of the Scheme (30 years for new gantries, 40 years for new
carriageway construction, and 120 years for new bridges), it is not
considered appropriate for decommissioning to form part of each
environmental topic assessment. Instead, the focus will be on seeking to
minimise disruption and to re-use materials that will also form part of the
Materials Assessment (chapter 11).
Identifying potential effects
5.6.4
Schedule 4 of the EIA Regulations requires: “A description of the likely
significant effects of the development on the environment, which should
cover the direct effects and any indirect, secondary, cumulative, short,
medium and long-term, permanent and temporary, positive and negative
effects of the development, resulting from:
a)
the existence of the development;
b)
the use of natural resources;
c)
the emission of pollutants, the creation of nuisances and the
elimination of waste; and
d)
the description by the applicant of the forecasting methods used to
assess the effects on the environment”.
5.6.5
The terms “impact” and “effect” are used interchangeably throughout this
ES.
5.6.6
A range of environmental topics may be affected by the Scheme. Effects
may be negative or positive, temporary or permanent. They may also be
described as:
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a)
Direct or Primary Impacts: caused by activities which are an integral
part of the Scheme resulting in a change in environmental
conditions, such as construction works causing an increase in dust
concentrations in the air;
b)
Indirect or Secondary Impacts: due to activities that affect an
environmental condition or receptor, which in turn affects other
aspects of the environment or receptors, for example, drainage
from the construction site increases sediment in the receiving water,
which in turn affects aquatic organisms ;
c)
Cumulative: comprising multiple effects from different sources
within the Scheme, or in combination with other developments, on
the same receptors;
d)
Residual: effects that remain after the positive influence of
mitigation measures are taken into account; or
e)
Temporary: effects that would last for a limited duration, for
example, dust generated during construction.
5.7
Assessing significance
5.7.1
The significance of an environmental effect is typically a function of the
‘value’ or ‘sensitivity’ of the receptor and the ‘magnitude’ or ‘scale’ of the
impact. Combining the environmental value of the resource or receptor
with the magnitude of change produces a significance of effect category.
5.7.2
DMRB Volume 11, Section 2, Part 5 HA 205/08 ‘Assessment and
Management of Environmental Effects’ provides advice on typical
descriptors of environmental value, magnitude of impact and significance
of effects, which are reproduced in Appendix 5.2 of Volume 3 of this ES.
5.7.3
DMRB recognises “the approach to assigning significance of effect relies
on reasoned argument, professional judgement and taking on board the
advice and views of appropriate organisations. For some disciplines,
predicted effects may be compared with quantitative thresholds and scales
in determining significance. Assigning each effect to one of the five
significance categories enables different topic issues to be placed upon
the same scale, in order to assist the decision-making process at whatever
stage the project is at within that process”.
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5.7.4
In arriving at the significance of effect, the assessor also considers
whether the effect is direct, indirect, secondary, cumulative, short, medium
or long-term, permanent or temporary, positive or negative as set out in
paragraph 5.6.6.
5.7.5
Not all of the environmental topics will use the approach described above.
For example, some topics do not use a matrix based approach, but
instead use numerical values to identify effects (e.g. Noise and Vibration).
Some topics do not have agreed or standard methods of assessment or
scales of measurement for either value or sensitivity (e.g. Materials or
Geology and Soils). Therefore, each environmental topic specialist has
used the information provided above and in Appendix 5.2 of Document
Reference 6.3 (ES Appendices), alongside their topic-specific guidance
and their professional judgment to assess the significance of effects.
Where alternative bases of assessment apply, this is explained in the
appropriate chapter, with the relevant tabulation derived from DMRB
contained in an appendix to each chapter. However, irrespective of the
criteria or approach that a topic requires, the descriptors of significance
listed in Appendix 5.2 of Document Reference 6.3 (ES Appendices) have
been used where appropriate.
5.7.6
Further details of the topic specific significance criteria used in this ES are
discussed in chapters 6 to 16.
5.8
Mitigation measures, enhancements and residual effects
5.8.1
Where potentially significant adverse environmental effects have been
identified during the assessment process, developing appropriate
mitigation has been an iterative part of the Scheme development following
the hierarchy below:
a)
Avoidance – incorporate measures to avoid the effect, for example,
alternative design options or modifying the Scheme programme to
avoid environmentally sensitive periods;
b)
Reduction – incorporate measures to lessen the effect, for example,
fencing off sensitive areas during construction and implementing a
CEMP to reduce the potential impacts from construction activities;
c)
Remediation – as a form of mitigation, for example the re-provision
of habitat to replace that lost to Scheme construction, or
remediation such as the clean-up of contaminated soils; and
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d)
Compensation – to be considered in the context where mitigation at
the affected location is not possible to avoid or reduce a significant
effect, in which case offsetting measures should be considered at
other locations.
5.8.2
The term "enhancement" refers to providing measures over and above
those needed to mitigate the adverse effect, and/or maximising the
opportunity for beneficial effects from the Scheme.
5.8.3
Effects that remain after mitigation are referred to as "residual effects".
Therefore, the key outcome of the assessment is the significance of the
residual effects after mitigation or enhancement.
5.9
Assessment of cumulative effects
5.9.1
The EIA Regulations require an assessment of direct, indirect and
cumulative effects with other projects and plans. Cumulative effects are
the result of multiple actions on environmental receptors or resources.
There are two types of cumulative effect:
a)
the combined action of a number of different environmental topicspecific effects upon a single resource/receptor ("in combination");
and
b)
the combined action of a number of different projects, cumulatively
with the project being assessed, on a single resource/receptor
("cumulative").
5.9.2
Further details on the scope of, and approach to, the cumulative effects
assessment is provided in each topic chapter and, specifically, in ES
chapter 16.
5.10
Deviation
5.10.1
Under the proposed Development Consent Order (“DCO”), a power of
deviation is provided. This allows the Scheme to be varied within strictly
controlled parameters, which are specified in the DCO. For instance, it
allows a change in the height of structures or gantries up to maxima which
are specified in the DCO or on the planning drawings, for each type of
work which may be subject to that power to deviate. Similarly, some
limited ability to move elements of the Scheme in the horizontal plane are
provided, for example the exact location of individual gantries may move
horizontally within the limits of the gantry siting zones shown on the Works
plans accompanying the DCO Application.
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5.10.2
The power of deviation, contained in articles of the DCO, has been
considered by those undertaking assessments for this ES having regard to
the scope for change under the proposed DCO.
5.11
Land access limitations
5.11.1
Access to land both within and out with the Order limits has been gained
wherever possible through liaison with land-owners, in order to undertake
the necessary environmental surveys. However, access was not afforded
to all areas. Within the Order limits, such areas comprise construction
compounds 5, 8 and 9. In areas where access was not available, the
baseline has been defined through desk-top study using aerial
photographs, or by surveying from the boundary of the land where
publically accessible. Professional judgment has been used, and
assessments have been based on a worst case scenario. This has been
described in the relevant topic chapters, and is summarised in Appendix
5.3 of Document Reference 6.3 (ES Appendices).
5.11.2
Such access issues are not considered to be detrimental to the baseline
information, nor the findings of the relevant assessments, for the reasons
set out in the relevant topic chapters and Appendix 5.3 of Document
Reference 6.3 (ES Appendices). Consequently, as it is considered that
sufficient information has been collected to undertake the assessments
required, in accordance with Inspectorate Advice Note 5, it was not
considered that there was a genuine reason for submitting an application
for rights of entry to survey the land pursuant to section 53 of the Planning
Act 2008 (“PA 2008”).
5.12
The Environmental Statement
5.12.1
The results of the EIA process up to the point of application, including
consultation, are presented in this ES submitted with the Application for
development consent. The structure of the ES is similar to the structure of
the PEI Report published in November 2014, but presents a final
assessment of the Scheme design that will be included in the Application
for development consent. This includes the proposed mitigation measures
to be included in the Scheme.
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