Measures have been identified to avoid or reduce adverse effects following the hierarchy below:
- Avoidance – incorporate measures to avoid the adverse effect, for example, alternative design options or modifying the proposed programme to avoid environmentally sensitive periods.
- Reduction – incorporate measures to lessen the effect, for example, fencing off sensitive areas during construction and implementing a Code of Construction Practice to reduce the potential impacts from construction activities.
The environmental information papers also set out the committed mitigation either on annotated maps or within the papers themselves. There are several different types of mitigation:
Effects that remain after primary, secondary and tertiary mitigation are referred to as residual effects.
Where it is not possible to avoid or reduce an adverse effect then compensation measures will be considered, for example the provision of replacement of habitat to replace that lost to the Proposed Development.
Where it is not possible to compensate or replace a loss, provision of an alternative may be the next best approach, for example contributing to habitat creation or management regimes in a location outside of the Proposed Development boundary. This approach acknowledges that the impact cannot be avoided, and that compensation will not suffice.
Enhancement measures are considered to be over and above any avoidance, mitigation and compensation measures required to neutralise any adverse effects of the Proposed Development. In many cases enhancement may be delivered through the implementation of other mitigation – for example landscaping may deliver a biodiversity enhancement.
The core approach illustrated in the mitigation hierarchy shown above is to avoid impacts, and if they cannot be avoided, to reduce them. If impacts still remain, then the next option is to reduce or remedy the impact or compensate for it. The advice of specialists or statutory consultees may be required to advise what is considered satisfactory compensation; it may only be considered ‘compensation’ if it genuinely replaces what is lost. Otherwise, it may be considered offset. New planting in place of lost mature broadleaved woodland will obviously not be totally a satisfactory substitute, especially in the short term.
How will mitigation be secured?
Mitigation will be secured through the requirements of the Development Consent Order which grants permission of the Proposed Development to be built.