7.2 Environmental Impact Assessment

The European Commission Directive on Environmental Assessment (85/337/EEC) (1985) has subsequently been amended by Directive 97/11/EC and also Article 3 of Directive 2003/35/EC. The Directives set out a framework for environmental impact assessment which has been enacted in Scotland principally by means of the Environmental Impact Assessment (Scotland) Regulations 1999 as amended. These regulations are applicable to specific development projects rather than strategies, plans or programmes.

An EIA draws 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 such effects, are understood by relevant stakeholders, the public and decision makers prior to any decision being made.

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.

The level of detail at which the assessment is conducted should be appropriate for the stage and type of option.

Various techniques may be employed to identify potential environmental impacts/issues:

• Use of environmental objectives - early identification of environmental objectives may allow particular topics to be identified to provide a focus for consideration of impacts. Such objectives (established policy directives, using the terminology introduced in Section 3) may be found in Development Plans or strategies prepared by planning authorities or other agencies and will generally be applicable at a wide area level. An option's planning objectives may include one or more which are focussed on environmental concerns;
• Involvement of experts - experts on the assessment team should set out their independent view of potential impacts based on their own knowledge and experience;
• The use of standard checklists - standard topic lists can be defined which set out, for each topic area, a description of the potential impacts, the geographical level of importance of the impact, the magnitude of the impact and the nature of the impact (e.g. short/long term, reversible/irreversible etc);
• Desk studies - a rapid search of published information (such as Development Plans and agency websites) can identify areas of sensitivity and issues of environmental concern. Development Plans can also assist in identifying potential land-use change and predicting future environmental conditions;
• Preliminary consultation with statutory, transport and land-use planners/practitioners and official bodies with an interest in the likely environmental effects who may have specific knowledge of the locality or experience of considering the impacts of particular types of option on their area of expertise;
• Comparison with the impacts of other similar options, which may be revealed through literature surveys; and
• Network analysis involving monitoring data, mathematical models, GIS, other mapping matrices and expert judgement.

At the strategic level, a useful approach will be to draw upon the above sources to identify environmental constraints and objectives affecting the study area. This can be used to set the scope for the initial stages of assessment and to guide development of the option. As more information becomes available about the emerging transport options, the scope of the assessment may need to be revisited - the nature of the option will be a key factor governing the range of potential effects on the environment.

Selected indicators used at the option development stage should also be capable of use in monitoring the performance of options following implementation.

Indicators that have been used to describe the baseline environment and objectives of a plan, or programme can often be used for monitoring as part of the SEA process.