Potential effects in environmental statements

3rd August 2012

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Following on from Hyder Consulting's article on the length of environmental statements, Andrew Saunders and David Hoare examine the need for including a potential effects section in environmental statements

The Environmental Impact Assessment (EIA) Regulations require an environmental statement to contain: “a description of the likely significant effects of the development on the environment.”
To comply with this requirement, it has become common practice to describe the effects of a development on receptors by reporting the effects in the absence of mitigation (potential effects), then introducing the proposed mitigation measures, before reporting the effects with mitigation (residual effects).

Not only can this make environmental statements unnecessarily long, it can:

  • make the assessment difficult to follow;
  • raise undue concern by reporting effects without consideration of mitigation measures; and
  • lead to the identification of unlikely effects, as opposed to “likely significant effects”.

These issues are compounded with the advent of more topic areas being added to environmental statements (sustainability, health and materials, for example), where reporting the assessment in this way can appear clumsy.

In practice

The following example demonstrates how the result of providing a standard mitigation measure is commonly reported:

  1. A potentially significant effect on a watercourse is identified due to risks associated with fuel storage.
  2. Mitigation is then identified in terms of the provision of a bunded fuel tank and compliance with Pollution Prevention Guidelines from the Environment Agency and the Scottish Environment Protection Agency.
  3. The residual effect is then reported as “no significant effect”.

Although this approach is methodical and commonly used, it seems convoluted and contributes to overlong assessments. It also takes away the focus from the overall conclusion of “no significant effect”.

So what options could be considered for negating the need for the reporting of potential effects; significantly reducing the size of environmental statements, while still complying with the EIA Regulations?
In the first instance, it is important to distinguish between the embedded mitigation/design measures of the development and the “measures envisaged to prevent, reduce and where possible offset any significant adverse effects on the environment”.

A summary of the former can be presented early on in the environmental statement, together with an explanation as to the benefits of each individual embedded mitigation/design measure.

Providing this summary upfront allows for the topic assessment chapters to assess the development as it is being presented in the planning application, and also allows for the sections on topic-specific mitigation to focus solely on the mitigation measures required over and above those that have already been incorporated into the design of the development.

In terms of the topic assessment chapters, one option would be to describe in detail the mitigation measures designed to prevent, reduce and offset significant effects (following the description of the baseline conditions), and then report the actual effects with mitigation measures in place (residual effects).

After all, mitigation measures are now an integral part of a development, so it could be argued it is disingenuous to describe effects in the absence of mitigation measures in any event. However, there is the possibility that this approach means that the applicant can’t take credit for mitigation measures, or that the effectiveness of mitigation measures cannot be understood.

Therefore, a second option, where mitigation measures make a fundamental difference to the assessment, would be to report them in the “residual effects” section.

The information can either be put into a table to demonstrate the results with and without mitigation, or reported in the main body of the text. For example: “The predicted noise level at receptor X, in the absence of the noise barrier, was predicted to be 66 decibels. However, with the provision of the noise barrier, the noise level is predicted to be 56 decibels.”
This approach allows the effects of the mitigation measures to be succinctly reported in one place, without having to follow an audit trail to arrive at the final conclusion.

These options are presented for consideration only. In our experience, it is always advisable to seek advice from the project legal team when considering the structure of an environmental statement, particularly if your structure differs from the usual common practice.

Furthermore, you may be confined to using a structure given in specific guidance, such as the Department for Transport’s Design Manual for Roads and Bridges (DMRB). Although, interestingly, even in the case of the DMRB, the guidance on reporting potential effects varies depending on the location of the development. For projects in England potential effects do not need to be reported, whereas in Scotland and Wales they do.

This article was written as a contribution to the EIA Quality Mark’s commitment to improving EIA practice.

Andrew Saunders is a director of environmental services at Hyder Consulting, and David Hoare is a principal environmental consultant.


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