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Strategic Environmental Assessment (SEA) is about how a plan will affect the environment.

First published:
7 May 2019
Last updated:

It is a formal process for assessing the effect of a plan or programme on the environment.


The aim of SEA is to:

  • provide a high level of protection to the environment
  • promote sustainable development
  • integrate environmental considerations into the preparation and adoption of a plan or programme


It is the responsibility of:

  • the organisation preparing the plan, or
  • the organisation on whose behalf it is being prepared

to decide if it requires an SEA. Each case needs to be considered on an individual basis. In some instances, you may need to determine the significance of environmental effects. Guidance and examples are available at Strategic Environmental Assessment Directive: guidance on


    Stages in the SEA process

    It is important that you include SEA at the beginning of a plan preparation, so that it is an integral part of the process. 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 plan or programme on the environment

    Contact details

    To inform us about your SEA, please:


    phone: 029 2082 3178  

    Rydym yn croesawu galwadau’n Gymraeg / We welcome calls in Welsh

    post to:

    Strategic Environmental Assessment
    Land Nature and Forestry Division
    Department for Economy, Skills and Natural Resources
    Welsh Government
    Cathays Park 2
    CF10 3NQ