Environment

Strategic Environmental Assessment (SEA)

When do I need a Strategic Environmental Assessment?

A Strategic Environmental Assessment (SEA) is used to assess the validity of plans, programmes and policies in terms of environmental impact.

You may need an SEA if you are producing:

  • Neighbourhood plans
  • Strategic transport plans
  • National infrastructure plans
  • Local development plans/local plans
  • Spatial development strategies

There are some other plans and programmes that will require an SEA too.

Who decides if I need an SEA?

The Local Planning Authority, Planning Inspectorate or relevant Regulator will advise if an SEA is required.

An Environmental Planner can prepare the relevant documentation to apply for a ‘Screening Decision’, which determines if an SEA is required.

What are the similarities and differences between an Environmental Impact Assessment (EIA) and an SEA?

Both of these processes are statutory requirements, and both have similar steps:

  • Screening – is an EIA or SEA required?
  • Scoping – if it is required, what should be assessed?
  • Assessment – what are the likely effects of the proposals?
  • Reporting – accurately and concisely communicating the likely effects and mitigation.

Stakeholder engagement and statutory consultation are legally required and essential for both EIAs and SEAs.

The main difference is that SEA is applied to strategic and large scale plans and programmes, such as local plans.  However, an EIA is focused on a specific planning project that may affect the environment.

Although an EIA does encompass both environmental and social issues, an SEA also includes economic issues.

What are the similarities and differences between a SEA and Sustainability Appraisal?

The SEA process is a legal requirement for certain types of plans or programmes, and Sustainability Appraisals are a requirement for strategic development strategies and local plans. This means there are different procedures that are followed, with an SEA having a legal framework and a Sustainability Appraisal having an informing role.

They are both tools which can be used in the plan-making process, but there is no legal requirement for a Sustainability Appraisal of neighbourhood plans, although the plan must demonstrate sustainable development.  A neighbourhood plan may require an SEA if it is likely to result in significant environmental consequences.


If you think your project needs an SEA, EIA or Sustainability Appraisal, speak to our environmental experts on +44 (0)1225 459564 or enquiries@engain.com

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To discuss your project requirements, please contact our experienced team