Mark Topping is director of design at consultancy Lanpro
The requirement for a minimum 10 per cent biodiversity net gain (BNG) came into force for small sites in February last year.
The requirement was introduced under Schedule 7A of the Town and Country Planning Act 1990 (as inserted by Schedule 14 of the Environment Act 2021). Developers must demonstrate how they plan to achieve a minimum 10 per cent increase in biodiversity for most new developments. Its implementation can make substantial changes to the layout of sites and the way in which they are constructed.
“Probably the most significant challenge is the new skill set required – ecologists are suddenly in short supply”
Frequently, BNG will require a combination of onsite and offsite habitat creation and enhancement, and the former is most relevant to construction companies. Significant habitat creation and enhancement must also be managed and monitored for a minimum of 30 years. BNG has been accepted quite positively by the development sector, and many developments achieved a minimum 10 per cent biodiversity uplift prior to the legal requirement to do so.
Another significant benefit is that land under public ownership that is unsuitable for particular uses, such as land prone to flooding, may benefit from the offsite provision of BNG. Construction companies will have already had a role in enhancing such sites to be of benefit to the wider community – plant and animal, as well as human.
‘Green infrastructure-led schemes’ take the existing environmental parameters as a base and deliver projects around this. This approach has been welcomed and encouraged by local planning authorities, both before and after BNG became mandatory. With the legislation now in place, the make-up of sites will move from developer-led to environment-led, and the construction sector may need to engage with potentially complex ecological considerations.
There are already many excellent examples that show an intelligent and pragmatic approach to providing BNG. Simple changes to the way in which developments are constructed can considerably benefit the capital costs. As such, an intrinsic understanding of the site at the outset, and a parameters-based approach to the site’s layout, working with the fabric of the site, greatly improves the process.
Tech solutions to expertise shortages
Probably the most significant challenge attached to BNG is the new skill set that is required within construction teams – ecologists are suddenly in short supply.
This is also true of the local authorities with which the construction teams work: according to a survey conducted by Chartered Institute of Ecology and Environmental Management, in 2022, some 26 per cent of local planning authorities did not have any access to ecological expertise.
However, the shortage of ecologists could be helped by a technological solution. CAD programs could evolve to incorporate baseline habitats and then automatically calculate BNG results as designs are tweaked and changed during the construction process. This would allow the client to see the BNG implications of design in ‘real time’ and design sensitively while reducing the time needed for ecologists to assess BNG multiple times per site.
Taking this a step further, there is almost certainly potential for AI to contribute to some aspects of the challenge.
Clearly, one measure of the success of BNG is the roll-out of well-designed sites, based on good advice. Essentially, this comes down to appropriate design – designs that are maintainable in perpetuity.
Clear management plans should be created to enable this, and should cover the full 30-year period to ensure landscape management is adaptable to evolving aspects such as increased development in proximity and environmental changes. One aspect of this is also a clear understanding of the soil composition of sites, and protection of existing habitats and soils through construction.
Looking ahead, there are many issues to resolve in relation to the provision of BNG. And when these issues are ironed out, the standard of new development will improve exponentially.
