Blog: Designing for Biodiversity Net Gain

At the time of writing, summer seems like something of a mythical beast, but soon enough we will be into autumn, and before long it will be November. As well as the usual building of bonfires, and of course World Jellyfish Day, November will see the rest of England becoming familiar with a concept that developers here in Cornwall have been dealing with since 2020 – Biodiversity Net Gain.

Biodiversity Net Gain (BNG) seeks to protect, maintain, and ultimately improve the natural environment while developing the built environment. The Environment Bill 2019-2021 will require all major development projects in England to demonstrate a 10% net improvement in the natural environment as a result of the works, with these improvements protected and maintained for a minimum of 30 years via Planning conditions, agreements and covenants.

There are several triggers that would define a development as a major development, but common projects would be the provision of 10 or more dwellings, an outline proposal for dwellings on a site 0.5 hectares or larger in area, or provision of 1000m² or more of new floorspace of any usage class. However, in April 2024 the government plans to extend BNG requirements to smaller sites too.

Cornwall Council decided to implement the 10% net gain requirements for major development in March 2020, and has incorporated the policy into its Climate Emergency Development Plan Document.

These improvements in habitats, green spaces and natural infrastructure can be achieved either on site, on other land that the developer owns or controls, or, as a last result, at one of a number of licenced land banks the government’s Environment Agency is registering and overseeing.

But how can we measure something as nebulous as the natural world? 

At a macro level we are all familiar with the demonstrable effects of climate change, but what about at the scale of a small development of new houses? Natural England have released a calculation tool which, in the hands of a properly qualified person, can be used to put definable numbers and metrics to these seemingly amorphous inputs.

PLACE Architects regularly work alongside a number of excellent local ecologists, and are ideally placed to help you assemble and co-ordinate a design team for your development project, be it major or minor in scope.

Complying with any new regulations can be a challenge, and may sometimes seem onerous. However, it is important to understand the context in which these new requirements have been drawn up. Wildlife populations are in decline worldwide, and the UK has been particularly badly affected. We need to ensure that development of the built environment does not further jeopardise the natural one.

Development sites that incorporate green spaces and preserve and enhance natural habitats have been shown to have a range of benefits from environmental, to physical and mental wellbeing. 

Here at PLACE Architects, we can help you design exciting, enriching plans for your works that enhance the both natural and built environment, and create spaces that are inspiring and delightful for everyone.