Designing With Nature

Designing with nature has always been a key part of the masterplanning process; however, we have found that meeting the BNG targets requires a greater level of interdisciplinary collaboration. 

While the concept of BNG is simple — a site’s biodiversity has to end up in a measurably better state than at the start of the development — in practice, the approach to BNG can vary greatly from site to site.

Defra has a tool which assesses habitats and calculates the BNG units. The best way of achieving 10% BNG is to minimise the loss of higher-value habitats.

Ultimately the site’s natural context and development objective will inform the approach to BNG. For example, on strategic greenfield sites that are in high-intensity arable use, the habitat baseline is often relatively low. In these cases, a combination of landscape-led masterplanning and ecologically sensitive landscape design will typically deliver around 10% BNG. 

Meeting BNG targets in an urban setting can be more challenging, as while some urban brownfield sites may have a lower value habitat baseline, there might be very little room to deliver the required net gains — even with innovative approaches to urban greening.

And, of course, high-value habitats can be found within greenfield and brownfield sites and these tend to be more challenging to compensate.

Practical Steps to Success

The delivery of 10% BNG can be complex and the approach will vary depending on the site context. It requires interdisciplinary collaboration and input from specialist ecological consultants.

To support the best outcomes for the development and for biodiversity we suggest:

1. Engage with ecological consultants early to establish the BNG baseline for the site. A high-value biodiversity baseline is likely to require very large offsets. 
2. Conduct ecological survey work at the right time of year. It is seasonal: missing a survey window can cause delays to the planning process.
3. Identify any high-value habitats to be retained within the proposals. Development should seek to retain areas of higher habitat value as the loss of these is more difficult to compensate.
4. Establish a high-level BNG brief to inform the masterplan and green infrastructure proposals that prioritises habitat restoration, creation and enhancement on site. 
5. Test the BNG requirements against the development brief early in the development process, considering how the requirements for both can be accommodated within the site masterplan. 
6. If initial assessments indicate that enhancing and restoring biodiversity within the site boundary cannot be achieved, then alternative off-site alternatives should be considered.
7. Be flexible about the development boundary: excluding or including key areas around a site periphery can be key to meeting the BNG requirements.

Defra has recently issued guidance on how local planning authorities can ensure that developers meet the requirements for BNG. This sets out the need for a clear mitigation hierarchy where enhancing biodiversity within the redline of the site is prioritised. If off-site gains are needed, this can be on the developer’s own land or through buying biodiversity units. Statutory credits are the last resort, but all three options can be combined if needed, provided the hierarchy is followed.

If the BNG requirements cannot be achieved on site, the Savills Natural Capital Environmental Exchange provides a bespoke brokerage platform. This delivers a map-based mechanism to connect parties seeking or providing natural capital offsets.

Conclusion

The BNG rules can seem complex to understand and challenging to navigate in practice. However, a collaborative approach to masterplanning that brings together a range of environmental disciplines and expertise creates a pathway to success.

Crucially, collaboration needs to bring together the right people at the right time. It therefore needs to be forward planned, and based around a full understanding of the site and the development context. This kind of joined-up, strategic approach is, in our experience, the most effective way to create the best outcomes for developments, planning authorities and for nature.

Further information

Contact Clare Mitchell or Joe Dance

Read more about BNG and the planning system here.