Matthew Baldwin is a project director at McBains, a property and construction consultancy
The delayed requirements on construction companies to meet new biodiversity net gain (BNG) rules – where they are required to deliver a net positive for the local environment, for example by creating new habitats and green spaces – are now in force.
The regulations were originally due to come into effect in November 2023, before the government postponed the legislation initially until January, and then February.
Because of this lack of clarity on implementation, many contractors may – quite reasonably – not have considered the range of options they could take to create at least 10 per cent more of biodiverse habitat.
But now the regulations are in place, here’s a five-point guide on how to deliver BNG:
1. Get to grips with government regulations
Last November, the government published draft biodiversity net gain planning practice guidance, including the statutory biodiversity metric, which is critical for calculating the correct biodiversity gain, and the draft biodiversity gain plan template, which will help developers prepare for the planning application stages. These materials will ensure that developers and planning authorities have access to the necessary tools and information to effectively implement BNG.
2. Check with your planning authority on any local standards
It’s not just national guidance you should check. Some local planning authorities are setting their own local standards, which may require more than a 10 per cent BNG. For example, property consultancy Carter Jonas has been tracking and analysing the emergence of local BNG policies. At the end of 2023, Guildford, Brighton and Hove, and Worthing already required or encouraged a percentage net gain higher than 10 per cent. Many other local planning authorities are mulling over more strenuous BNG requirements – according to Carter Jonas, Kingston upon Thames and Tower Hamlets may require a minimum of 30 per cent net gain.
3. Make onsite BNG the priority
The best option is for BNG to be delivered onsite locally. This is because it will generally be cheaper as often the development is likely to be on brownfield rather than greenfield land (although the cost will depend on factors such as the location of the development and the type of habitat to be replaced). If BNG has to be delivered offsite, then land nearer the site will score more highly than land further away. As a result, it is advantageous for developers to find sites as locally as possible for their offsite enhancements.
Going down the route of purchasing credits is likely to be more expensive: the government currently prices individual trees at an indicative cost of £42,000, for example.
4. Consider the options
Some of the options developers could consider are:
- Living walls or green roofs. These enhance biodiversity by providing habitat for flora and fauna and are a good option for large-structured developments, such as car dealerships, for example. Some are already doing this – in Buckinghamshire, Porsche and Bentley dealerships are incorporating living walls at new outlets on a former leisure centre site. Live roofs can help insulate and cool buildings too. Remember they do require maintenance – an important factor as BNG requires all habitats to be secured for at least 30 years.
- Landscaping with native species. Native plants are adapted to the local ecosystem, promoting a more sustainable environment. These can work especially well in new housing developments.
- Biodiverse parking areas. Parking areas (in supermarket developments, for example) could be designed with permeable surfaces and the parking lot could incorporate green spaces. This could include tree islands, rain gardens or bioswales, for example.
- Wildlife-friendly design. Consider including features like bird boxes, insect hotels, or bat roosts in designs to support local wildlife.
- Mixed-use development. If feasible, consider incorporating mixed-use elements into the development, combining commercial or residential spaces. This can create a more sustainable and diverse urban environment.
- Don’t leave it too late. The best plan is to account for BNG requirements early. Factoring site space allocations for biodiverse planting into schemes at the site appraisal stage could negate the need for costly design solutions, monetary offsets, or potential ongoing maintenance challenges. Of course, this will need to be balanced against land cost, build costs, and the retailer and brand requirements.
5. Establish a monitoring system
Finally, make sure to implement a system to monitor the ecological performance of the site over time to demonstrate commitment to BNG.
