Guest blog: a bluffer’s guide to EIA


In this guest blog, Katharine Blythe – senior consultant at Ramboll ENVIRON – sheds some light on Environmental Impact Assessments in her bluffer’s guide.


Environmental Impact Assessment (EIA) has a bit of a bad press.

Cynics state that it is a study funded by the developer, and therefore inevitably biased. Supporters assume that the very fact an EIA has been completed for a development magically removes all environmental impact. Unsurprisingly, neither of these is true. There is a lot of misunderstanding of the process – and this post will briefly explain what EIA is, what it involves and – probably the most important – why we bother with EIA at all.


First – the regulation bit

EIA Regulations in the UK[1] enact an EU Directive which outlines what an EIA in the EU must contain, when one must be completed and how decision makers must take it into account. These regulations are not riveting reading. However, the key issue is that an EIA must be carried out before consent for a development is granted, where there is potential for a “significant” impact on the environment[2] because of the characteristics or location of a development.

EIA really refers to the assessment process.

The report arising from this is called an Environmental Statement (ES) (excitingly to be renamed an EIA Report in 2017 when changes to the EU directive come into force) and this is submitted with an application for planning consent. Under the EIA Regulations some very large projects (new roads, power stations, chemical works etc) will always require an EIA and ES.   Other projects exceeding certain thresholds may require EIA if the Planning Authority (usually the local council) considers the development could have a significant environmental effect.

The EIA Regulations require certain things to be included in an ES – namely:

  • a project description;
  • a summary of the baseline environment likely to be affected;
  • an outline of any alternatives considered (and justification of why the chosen location, process, or layout was preferred);
  • likely significant effects of the development on the environment– and how these effects have been predicted; and
  • measures to prevent, reduce and where possible offset any significant adverse effects on the environment – so-called mitigation measures.

A Non-Technical Summary is also required, summarizing the content of the ES to a lay-person.

Good practice and guidance for EIA has been produced by various professional bodies – for example, for assessments of ecology, landscape and traffic. Therefore the process of EIA can be amended and modified as best practice changes. This guidance generally pins down how to identify the vague concept of “significance” into quantifiable measures for each effect. Generally this is through comparing the “magnitude” of any impact, against the “sensitivity” of the bit of the environment affected – whether a home, habitat, river or view.


But what is EIA actually for..?

The Planning Authority has to take an ES into account when making its planning decision.  Therefore the report needs to be objective and scientifically-based to give the planning officers and their advisors enough information to establish what the impacts are likely to be and their effect on the overall environment.

What EIA is definitely NOT for is to “sell” the development by painting a rosy picture.  It is impossible to design out all environmental impact from any development – and some of these impacts may potentially be significant, even with mitigation in place.  A wind farm, for example, will almost certainly have significant impacts on views from several locations. This does not mean the development must be refused, but the planning process has to weigh up whether such changes would be acceptable, or could be made so.

However, EIA is also integral in the sensitive design of a development, through consideration of alternatives and development of mitigation. Its use as a design tool can minimize environmental impacts – but also, conveniently, minimize cost for the developer.  It is much cheaper to swap locations of plant on site at the design stage, for example, than build noise screens around them.

So although the finished ES may well end up being used as a makeshift table in a planner’s office[3], the process to reach this finished product, and to ensure that the completed development is as environmentally sensitive as it can be, is its real value.


[1] The Town and Country Planning (Environmental Impact Assessment) Regulations 2011 – Or the Scottish or Northern Irish equivalent
[2] Schedule 4 of the EIA Regulations defines aspects of the environment which could be affected to be “population, fauna, flora, soil, water, air, climatic factors, material assets, including the architectural and archaeological heritage, landscape and the interrelationship between the above factors”
[3] Yes, this is always guaranteed to give me pride in my job.