7.2.3 Mitigation Measures

Mitigation measures are those measures considered necessary to prevent, reduce and where possible remedy or offset any significant adverse impacts on the environment. They should not be an afterthought, but integrated in the final option(s) to ensure that the best environmental fit is achieved. Effects which cannot be mitigated should be acknowledged. Where an assessment identifies significant environmental impacts in the absence of mitigation, this suggests that an alternative option should be considered rather than seeking to mitigate an unacceptable option. At the strategic level, mitigation measures may have to be stated in generic terms which can then be used to guide the development of projects forming part of their implementation.

Mitigation measures can take many forms including:

Projects:

• Modal alternatives and measures to influence traffic flows (by means of policies such as road pricing or traffic control/management systems);
• Alternative indicative routes or sites (for nodal facilities);
• Alternative detailed design criteria for the source or receptor;
• Alternative construction methods; and
• Remedial or compensatory action such as noise insulation or relocation of species.

Strategies, Plans and Programmes:

• Changes to the wording of the plan or plan alternative;
• The removal of the plan alternatives that are unsustainable or do not promote the objectives;
• The addition of new plan alternatives;
• Devising new alternatives, possibly a combination of the best aspects of existing alternatives; and
• Identifying issues to be considered in environmental impact assessment of specific developments.

Where appropriate mitigation measures associated with a particular option can be identified, these should be stated and included as commitments in the assessment reporting. At the strategic level the potential for mitigation measures should be acknowledged and taken into account as far as possible. At the project level, the design of mitigation measures may need to be specified in some detail and a commitment made to their implementation.

If the assessment of effects is to be made assuming stated mitigation measures are in place, it follows that there must be confidence that any measures identified are capable of being delivered and that they have a real prospect of success.

More extensive information on project-related mitigation is contained in Mitigation Measures in Environmental Statements DETR 1997.