Planning with nature in mind

25th May 2023

Matthew Coe looks at the challenges of securing biodiversity net gain on environmental impact assessment projects

When the UK parliament passed the Environment Act 2021, it stipulated that all planning permissions granted in England will be required to achieve a minimum of 10% biodiversity net gain (BNG). This is due to become mandatory for planning applications submitted under the Town and Country Planning Act from November 2023 and for Development Consent Order applications from November 2025. This article outlines how BNG can be achieved as part of environmental impact assessment (EIA) projects and the complexities of trying to deliver BNG alongside an EIA.

The purpose of EIA is to identify significant environmental effects and, where appropriate, suggest measures to mitigate significant adverse effects. To ensure it is deliverable, primary mitigation measures must be included within the planning application (red line) boundary (RLB). However, achieving 10% BNG is not generally required to mitigate significant adverse effects. Therefore, providing measures within the RLB are mitigating significant adverse effects (e.g., for ecology, landscape and visual effects), and additional ‘enhancements’ could be provided outside of the RLB that would not require planning permission. Therefore, BNG does not need to be achieved solely within the RLB.

AECOM worked on an EIA for a road-widening scheme. Constraints either side of the road meant that achieving 10% BNG within the RLB would have been difficult. In addition, BNG was known as a key concern for the planning authority and local stakeholders, such as the parish council. Therefore, provision of off-site enhancements/BNG was considered crucial to the success of the scheme.

To maintain progress on BNG, AECOM set up a BNG working group involving key technical and client team members to develop an extensive list of ideas for off-site BNG. The aim was that off-site BNG should be close to the RLB (all options within 2km and some much closer). The long list developed included land owned by parish councils, rural estates, public bodies and utility companies. The Applicant subsequently contacted each group to understand their willingness to participate and what BNG opportunities they were interested in (and how much this contributed to delivering 10% BNG).

Throughout this process, AECOM considered which BNG options would provide the best outcomes. One option was to make a financial contribution to an offsetting provider, and this may be valid if the offsetting provider can commit to defined local projects but, in this case, it was preferred to ensure that any BNG delivered would benefit the local communities affected by the scheme.

Key challenges and lessons learned included:

  • Allowing time in programme for potential slow responders and for discussions to develop. While some options were not available or viable, discussions did still uncover potential new possibilities that were more fruitful. Early engagement with the parish council provided particularly useful knowledge about local biodiversity enthusiasts.
  • Agreeing what BNG information the local authority expects to see submitted with the planning application. A risk was that a signed heads of terms or similar would be needed to give comfort that BNG was deliverable. In this case, concerns about deliverability were less acute, because the land parcel providing most of the 10% BNG was owned by the planning authority, although the BNG offer still included enhancements on private land. Early input from a land agent is required.
  • The Environment Act 2021 requires enhancements to be maintained for 30 years. The total costs for this can be significant. Does the client have funds available and when do the monies need to be released? If an offsetting provider is used, the total costs may need to be paid upfront.
  • It is still likely that planning conditions will be required to refine the BNG offer and confirm what will be delivered. Therefore, there is still flexibility for the client to amend the BNG offer if required due to changes in landowner circumstances.

BNG has developed significantly over the past five years. Now soon to be mandatory and already expected by many local communities, this article shows that, while not without challenges, there are opportunities for BNG enhancements to be provided outside of the RLB and generate a good news story for any development.

Matthew Coe is principal environmental consultant at AECOM


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