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Strategic Environmental Assessment

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Strategic Environmental Assessment (SEA) is a formal process for assessing the effect of a plan or programme on the environment.

It is legislated in the European Commission SEA Directive and is transposed into the UK through the SEA Regulations.

There are separate Regulations for plans or programmes relating solely to England or to both England and other parts of the UK, and solely to Wales, Scotland or Northern Ireland.

The aim of SEA is to provide a high level of protection to the environment and to promote sustainable development by the integration of environmental considerations into the preparation and adoption of plans or programmes.

Examples of plans and programmes which require SEA are available in the ‘Practical Guide to the SEA Directive’. However, there is no exhaustive list and each case is considered on an individual basis.

The responsibility for deciding whether a plan or programme requires an SEA lies with the organisation that is going to prepare the plans/programmes or the organisation on whose behalf it is being prepared. The ‘Practical Guide’ explains this.

In some instances the significance of environmental effects may need to be determined. The SEA Directive provides a list of criteria that can be used for judging whether an environmental effect is significant or not. 

Stages in the SEA Process

It is important that SEA is included at the very beginning of a plan or programme, so that it is integrated into decision-making throughout. The stages in the SEA process are:

  • Setting the context and objectives, establishing the baseline and deciding the scope:
  • Developing and refining alternatives and assessing effects
  • Preparing the Environmental Report
  • Consulting on the draft plan or programme and the Environmental Report
  • Monitoring the significant effects of implementing the plans or programmes on the environment

With regard to the consultation requirement of SEA, the Directive prescribes what bodies should be consulted, the process of public consultation, where required, and various practical aspects of consultation. 

EU Directive (2001/42/EC) (External link)

Environmental Assessment of Plans and Programmes (Wales) Regulations (SI 2004/1656 (W/170)) (External link)

Strategic Environmental Assessment in Wales

Further guidance on aspects of SEA in Wales will be of use to those who are involved in carrying out SEA. It is important to emphasise, however, that this guidance is not exhaustive and that anyone considering SEA should refer to the Regulations and the ‘Practical Guide to the SEA Directive’.

Contact Details

To inform us of SEAs that you are doing, please email:

Or by post:

Strategic Environmental Assessment
Climate Change and Natural Resource Management Division
Department for Natural Resources
Welsh Government
Cathays Park 2
CF10 3NQ

Tel: 02920 823178