This section provides guidance on assessing the environmental impacts of a transport option, whether this comprises a strategy, plan, programme or specific project. It provides guidance on the general process to be adopted in the Part 2 Appraisal and outlines the issues and methodologies relating to different topic areas. Environmental assessment is conducted to contribute to the appraisal of the transport option within the terms of the Environment Criteria.
The Part 2 Appraisal requires an assessment of the environmental impact of an option against a number of Environmental sub-criteria. It should be noted that these issues classified as sub-criterion will not necessarily be common to all assessments.
The Environmental sub-criteria considered in detail during Part 2 Appraisal, include:
The scoping exercise undertaken during Part 1 Appraisal should identify the relevance of each sub-criterion to a particular option and whether any additional topics need to be covered. The Part 1 Appraisal will also determine the scope and level of detail required for the appraisal against each sub-criterion at Part 2.
The underlying fundamental principles are that practitioners should concentrate on significant impacts and that both qualitative and quantitative measures should be used to determine significance, provided that these measures are understandable and robust.
Significant impacts may be defined as those which should be given due consideration in decision-making. Where an impact on a particular sub-criterion is unlikely to be significant, the detailed assessment as reported in Part 2 Appraisal may not be necessary. On the other hand if the scope of the assessment is too narrowly defined, significant issues may not be identified at the outset of the study and subsequent data collection and analysis may be inadequate. Issues which are significant at the specific option level (such as land take from a particular habitat of ecological value) may not be significant at the more strategic level.
The process of assessing environmental impacts should be fully integrated with the development of the option and should therefore be applied at the strategic level, during option formulation and appraisal, and at the detailed project level. Early consideration of environmental issues should result in the development of options that avoid environmental constraints, or result in a reduced environmental impact and a lesser need for mitigation measures and their associated costs. It should also inform the consideration of alternatives and the choice between them.
Additional Environmental Assessment Requirements
Before substantive work is undertaken the need for a Strategic Environmental Assessment (SEA) or an Environmental Impact Assessment (EIA) should be considered carefully.
There is a certain level of overlap between the STAG Process and both SEA and EIA. However, duplication of effort can be avoided if the available guidance on SEA and EIA is reviewed prior to undertaking the STAG Process to ensure appropriate methodology and approach.
In summary, if a SEA or EIA is undertaken as part of the STAG Process, the focus should be on:
Strategic Environmental Assessment (SEA):
When considering the environmental impact of options a Strategic Environmental Assessment (SEA) may also be required of the transport plan, programme or strategy. Similarly, a transport project may also require an Environmental Impact Assessment (EIA) to be undertaken in addition to the STAG study.
Project Environmental Impact Assessment (EIA):
The Environmental Impact Assessment (EIA) process provides a means of drawing together, in a systematic way, an assessment of a project's likely significant environmental effects. This helps to ensure that the importance of the predicted effects, and the scope for reducing them, are properly understood by relevant stakeholders prior to any decision being made.
A transport plan or programme requiring a STAG assessment may also require a SEA, within the terms of the Environmental Assessment (Scotland) Act 2005. Similarly, a transport project may require a STAG and also require EIA to be undertaken within the terms of the EIA Regulations. Practitioners should refer to the relevant legislation and Scottish Government Circulars for guidance on legislative requirements for assessment.
Until recently, EIAs of transport options tend to have been conducted on projects which have been fairly well defined (either at the outline planning stage or where detailed designs have been available). Examples have included road schemes, a rail freight terminal, a causeway and jetty improvements. This means that consideration of alternatives has been limited to, for example, variations in alignment or design rather than considering different modal solutions to address the particular transport problem.
The EC Directive 97/11/EC has increased the emphasis on the consideration of alternatives and on the reason for the choice of preferred option. The approach to the environmental assessment of transport options, including, at the strategic level, plans, programmes and transport corridor studies, needs to reflect this by incorporating the consideration of environmental issues at the option appraisal stage, early in the decision making process. Such strategic assessments will increasingly be used to select transport options for further development and implementation.
