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ENVIRONMENTALSTATEMENT: Environmental Impact Assessment Methodology

https://infrastructure.planninginspectorate.gov.uk/wp-content/ipc/uploads/projects/TR010019/TR010019-000267-6-1-ES-Chapters_05-EIA-Process.pdf

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:

1. a) Data Review – draw together and review available data;
2. b) Screening – determine the need for EIA;
3. c) Scoping – identify significant issues, determine the subject matter of

the assessment and the methodologies for undertaking the

assessment;

1. d) Baseline Surveys – undertake surveys and monitoring to identify

existing environmental conditions;

1. 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;

1. 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

1. g) Preparation of an Environmental Statement (“ES”).

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:

1. a) Air Quality;
2. b) Cultural Heritage;
3. c) Landscape;
4. d) Nature Conservation;
5. e) Geology and Soils;
6. f) Materials and Waste;
7. g) Noise and Vibration;
8. h) Effects on All Travellers;
9. i) Community and Private Assets;
10. j) Road Drainage and the Water Environment; and
11. 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:

1. a) direct effects on health and wellbeing through changes in noise and

air pollution, water quality and climate change;

1. b) lifestyle changes, such as encouraging travel by means other than

private car, for example encouraging walking and cycling;

1. c) effects on the local economy by changing access to employment;
2. d) effects on access to key services, particularly access to health

facilities;

1. e) changes to the built environment to promote exercise through a

healthy environment; and

1. 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

1. 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.

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:

1. a) the time that construction is expected to start, for effects arising

from construction (the start of construction for this Scheme being

September 2016);

1. 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

1. 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.

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 newcarriageway 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:

1. a) the existence of the development;
2. b) the use of natural resources;
3. c) the emission of pollutants, the creation of nuisances and the

elimination of waste; and

1. 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:

1. 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;

1. 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 ;

1. c) Cumulative: comprising multiple effects from different sources

within the Scheme, or in combination with other developments, on

the same receptors;

1. d) Residual: effects that remain after the positive influence of

mitigation measures are taken into account; or

1. 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”.

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:

1. a) Avoidance – incorporate measures to avoid the effect, for example,

alternative design options or modifying the Scheme programme to

avoid environmentally sensitive periods;

1. 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;

1. 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

1. 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:

1. a) the combined action of a number of different environmental topicspecific effects upon a single resource/receptor (“in combination”);

and

1. 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.

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.