Environmental Impact Assessments in Planning

Large developments may need an Environmental Impact Assessment. Here's when EIA applies and what it involves.

Environmental Impact Assessment (EIA) is a process that ensures the environmental effects of major developments are fully considered before planning permission is granted. It applies to the largest and most impactful projects.

When Is EIA Required?

The EIA Regulations divide projects into two schedules:

Schedule 1 - Always Requires EIA

Major infrastructure and industrial projects including:

• Power stations over 300MW
• Motorways and express roads
• Chemical installations
• Waste disposal installations for hazardous waste
• Airports with runways over 2,100m

Schedule 2 - May Require EIA

Projects that exceed certain thresholds and may have significant environmental effects. This is where most housing and commercial developments fall. Common thresholds include:

• Housing developments of 150+ dwellings or on sites over 5 hectares
• Industrial estates over 0.5 hectares
• Urban development projects over 1 hectare in sensitive areas
• Infrastructure projects above specified thresholds

For Schedule 2, the council (or the developer) can request a screening opinion to determine whether EIA is needed.

The EIA Process

1. Screening - is EIA required? The council considers the project's characteristics, location, and potential impact
2. Scoping - what should the assessment cover? The developer can request a scoping opinion from the council
3. Assessment - specialists assess each topic area using surveys, modelling, and professional judgement
4. Environmental Statement (ES) - the results are compiled into a formal document submitted with the planning application
5. Consultation - statutory consultees and the public review the ES
6. Determination - the council considers the ES alongside all other material considerations

What the Environmental Statement Covers

Typical chapters include:

• Traffic and transport - vehicle movements, highway safety, public transport
• Noise and vibration - during construction and operation
• Air quality - dust during construction, vehicle emissions
• Ecology and biodiversity - protected species, habitats, biodiversity net gain
• Landscape and visual impact - how the development looks in its setting
• Heritage - impact on listed buildings, conservation areas, archaeology
• Flood risk and drainage - surface water, groundwater, flood zones
• Socioeconomic - jobs, housing, community facilities
• Cumulative effects - combined impact with other nearby developments

Key Points

• EIA doesn't prevent development - it ensures environmental effects are understood and mitigated
• The ES must include mitigation measures for significant effects
• The process typically adds 6-12 months and £50,000-£200,000+ to project costs
• Failure to carry out EIA when required can result in the planning permission being quashed by judicial review