Southwest Environmental Limited

Small Sites Metric Calculation Tool

Here to help: If you need assistance filling out the Small Sites Metric Calculation Tool please email for a quotation phone numbers are at top of page if you prefer.

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Purpose:

Designed for smaller development projects in England where the biodiversity impacts are less complex and extensive. Simplifies the Biodiversity Net Gain (BNG) assessment process, making it more accessible to smaller developers and landowners.

Key Features:

Streamlined assessment: It focuses on a select range of habitat types and biodiversity features, reducing the amount of data required compared to the full Biodiversity Metric. User-friendly interface: It's typically available as a spreadsheet-based tool, making it relatively easy to use and understand. Tailored guidance: It includes specific guidance on how to apply the tool for different types of small sites.

Functionality:

Habitat Mapping:

Users map the existing habitats on the development site, using standardized habitat codes and descriptions.

Impact Assessment:

The tool calculates the biodiversity units lost due to the proposed development, based on the area and quality of affected habitats.

Habitat Creation and Enhancement:

Users input details of planned habitat creation or enhancement measures, such as planting trees or restoring ponds.

Net Gain Calculation:

The tool automatically calculates the overall biodiversity units gained or lost, factoring in both losses and gains.

Reporting:

It generates a report summarizing the assessment results, including the net gain or loss and proposed mitigation measures.

Availability and Use:

The Small Sites Metric Calculation Tool, as well as its user guide and supplementary materials, can be freely accessed and downloaded from the Natural England website: https://publications.naturalengland.org.uk/publication/6047259574927360 It's intended for use by qualified ecologists or professionals with appropriate expertise in biodiversity assessment and BNG.

Additional Considerations:

It may not be suitable for sites with highly sensitive habitats or protected species. For those cases, the full Biodiversity Metric may be required for a more comprehensive assessment. It's important to consult with relevant authorities and guidelines to ensure compliance with local BNG requirements.

The below section was written by a machine.

Technical Guidance: Navigating the Small Sites Metric (SSM)

The Small Sites Metric (SSM) is a simplified version of the Statutory Biodiversity Metric, specifically designed for smaller development projects where ecological impacts are less extensive. For developers in England, achieving a mandatory 10% Biodiversity Net Gain (BNG) is now a core requirement of the planning process. The SSM provides a streamlined route for quantifying these impacts without the need for the full complexity of the larger metric tool, provided the site meets specific criteria regarding size and habitat sensitivity.

Criteria for Using the Small Sites Metric

While the SSM simplifies data entry, its application is restricted to developments that do not fall under the "major development" category. Our ecology consultants ensure that your project qualifies for this route before commencing technical assessments. Typically, the SSM is applicable for:

• Residential Developments: Projects with fewer than 10 dwellings on a site area of less than 0.5 hectares.
• Non-Residential Sites: Developments where the floor space created is less than 1,000 square metres or the site area is less than 1 hectare.
• Site Constraints: The metric cannot be used if high-value habitats or protected species are present, in which case a Phase 1 Habitat Survey and the full biodiversity metric calculation may be required.

The Assessment and Reporting Process

To successfully navigate an SSM submission, precise habitat mapping and condition assessments are required. The process involves identifying baseline "biodiversity units" before development and calculating the units provided through on-site enhancement or creation. This data must be integrated into a robust planning statement to demonstrate compliance with the National Planning Policy Framework (NPPF).

Expert Support for Small-Scale Developments

Our consultancy provides the technical authority required to manage BNG requirements for small sites. By linking ecological findings with broader Environmental Impact Assessments (EIA), we provide a comprehensive route to regulatory consent. With over 15 years of industry experience and 900+ projects completed across the UK, SWEL offers the professional accreditation (IES/CIEEM) necessary to secure your project's future and ensure your biodiversity calculations are technically sound and ready for planning officer review.