Biodiversity Net Gain will soon become a fundamental part of planning consent due to legislation changes set out in the new Environment Bill. These changes include a mandatory Biodiversity Net Gain of 10% for most new developments.
What is Biodiversity Net Gain?
Biodiversity Net Gain is the process of improving a site’s biodiversity value. The biodiversity value of a site is calculated by using habitats as a proxy. The types of habitats, their condition and the species they support, or are likely to support, determines the value of the site before and after development.
What is a Biodiversity Net Gain Assessment?
A Biodiversity Net Gain Assessment weighs up the current baseline conditions of a site against the proposed development plans. To achieve net gain, the site must increase the number of biodiversity units available after the development is complete.
The following steps are used to calculate biodiversity net gain for a site:
- A Preliminary Ecological Appraisal is undertaken to collect baseline information for the site’s habitats and species. The number of biodiversity units a site is worth is determined from the habitat survey information using the DEFRA metric.
- The post development value in biodiversity units is determined using landscaping plans and the DEFRA metric. Habitats that are retained or created on site increase a site’s value. Additional biodiversity units can be gained off site using compensation sites.
- The net gain or net loss is calculated using the difference between the proposed and current development habitat data.
Plans for the site are needed to carry out a full BNG assessment, however, if plans are not available, the feasibility of achieving BNG onsite can be included as part of the PEA or can be included in a separate BNG Feasibility Report. Then, when plans for the site are finalised, a BNG Design Stage Report is produced as part of the Ecological Impact Assessment or as a separate document for submission to planning.
Biodiversity Net Gain requires a 30 year management plan to demonstrate how the proposed onsite and offsite habitats will be delivered after the development. This can sometimes be conditioned as part of the planning process and can be included in a Project Implementation and Construction Plan (BNG PICP) or Landscape Ecological Management Plan (LEMP). Our ecologists can help you through the full BNG process from determining the site baseline feasibility to achieving a net gain and planning permission.