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Last edited 04 May 2021
Environmental impact assessment EIA
The purpose of an Environmental Impact Assessment (EIA) is to ensure that the environmental effects of a proposed development are properly considered. An EIA provides the local planning authority with better information about certain types of projects, enabling them to make a more informed decision about whether permission should be granted and to allow imposition of more appropriate conditions and obligations to mitigate possible negative impacts.
The Town and Country Planning (Environmental Impact Assessment) (England and Wales) Regulations 2011 sets out a requirement to carry out an EIA as part of the planning application process for certain projects (generally those which are large or environmentally complex).
Carrying out an EIA can involve a considerable amount of work, can cause significant delays and incur additional costs to a project. It may therefore be advisable to enter into early consultation with the local planning authority to determine whether an EIA will be required, and if so, what it should contain and what methodology should be used to carry out the necessary assessments.
If an applicant is uncertain about whether an EIA is required, they can ask the local planning authority for a decision called a 'screening opinion' (or screening decision). They can also ask the local planning authority for advice about the required scope of the EIA; this is called a 'scoping opinion' (or scoping decision). If the applicant disagrees with these opinions, they can appeal to the Secretary of State who will then make a direction.
EIAs are required for developments described in Schedule 1 and Schedule 2 of The Town and Country Planning (environmental impact assessment) (England and Wales) Regulations. This includes a wide variety of projects such as:
- Power stations
- Certain industrial processes
- Certain transport projects
- Major projects (above certain thresholds set out in Schedule 2)
- Developments in sensitive or vulnerable locations (thresholds do not apply in sensitive locations such as national parks or national nature reserves where every project must be screened for environmental impact assessment).
- Unusually complex projects that may have adverse environmental effects.
An Environmental Statement (usually prepared by the developer) summarises the findings of the EIA process and is used primarily to inform decision makers regarding the environmental implications of the development. In addition, it should provide appropriate information for statutory consultees, other interested organisations and members of the public and should provide a basis for consultation.
An Environmental Statement may contain:
- A description of the proposed development and its use.
- An estimate of the likely residues and emissions resulting from the construction and operation of the development (water, air and soil pollution, noise, vibration, light, heat, radiation, etc.).
- An assessment of how the development complies with planning policy.
- An assessment of environmental opportunities and constraints.
- An assessment of appropriate alternatives. This may include an assessment of possible alternative sites, so it is important that this is done during the very early stages of a project - not as a process of post-rationalisation after the client has already selected a site.
- An assessment of the likely impacts of the development.
In April 2015, the Town and Country Planning (Environmental Impact Assessments)(Amendment) Regulations 2015 came into effect, raising the threshold above which a screening decision is required to determine whether an environmental statement is necessary, as set out in the Town and Country Planning (Environmental Impact Assessment) Regulations 2011. Controversially, this raised the threshold for industrial estates, residential developments and other urban developments from 0.5ha to five ha (or 150 units for residential developments).
In addition, in April 2014, the Council of the European Union approved changes to the environmental impact assessment directive with new elements including '...a mandatory assessment of reasonable alternatives studied by the developer, broader scope, as the EIA will cover new issues, and more detailed provisions on screening'. Member states have three years to incorporate the changes into national legislation (ref. EN, Council approves environmental impact assessment directive 14 April 2014).
In December 2016, the UK government launched a consultation on proposed changes to legislation that are needed to implement amendments introduced by the 2014 Directive. The consultation closed in January 2017.
In October 2018, the government published statutory instruments confirming that developers will still be required to undertake EIAs after the UK leaves the European Union, ensuring continuity of planning policy.
 Related articles on Designing Buildings Wiki
- Air quality.
- Alternative site assessment ASA.
- Construction environmental management plan.
- Ecological impact assessment.
- Ecological survey.
- Environmental engineering.
- Environmental impact.
- Environmental management procedures manual.
- Environmental modelling.
- Environmental net gain.
- Environmental permit.
- Environmental plan.
- Environmental policy.
- Environmental statement.
- Green plot ratio.
- In-combination effects.
- Scoping study.
- Screening decision.
- Permission for mining or working of minerals.
- Planning permission.
- Protected species.
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