Biodiversity is defined as the variety of plants and animals living within an area or habitat. The interactions between different species and their surrounding environments are known as ecosystems.
Diverse ecosystems are vital to the health of the planet and of our communities.
We depend on a thriving ecosystem for a wide range of environmental, health and social benefits. However, the UK has suffered a considerable decline in biodiversity over recent years, worsened by fragmentation and loss of natural habitats – partly as a result of development.
BNG is a new approach to planning and land management that leaves the natural environment in a better state than it was before. Most development will now need to achieve a 10% BNG as part of a planning application.
What BNG is
The Environment Act 2021 introduced new planning legislation which requires development to achieve a 10% BNG post-development. This new legislation applied to planning applications for major development received from 12th February 2024 and to planning applications for minor development received from 2nd April 2024.
This change must be calculated using the Statutory Biodiversity Metric tool to measure the biodiversity value of habitats before and after development. The Biodiversity Metric measures biodiversity value in Biodiversity Units (BU) using habitat as a proxy value for nature.
For more information on how to use the Biodiversity Metric: Read the Gov.uk guidance on the biodiversity metric.
BNG in Calderdale
The delivery of BNG must align with national legislation and guidance however, there are certain aspects which reflect the differences between local authorities and the habitats within them.
Further guidance for developers within Calderdale is provided below:
Exempt developments
The legislation does exempt some types of development. The following is a summary of the types of development exempt from the 10% BNG requirement:
- De minimis exemption - A development that does not impact a priority habitat and impacts less than:
- 25 square metres (5m by 5m) of on-site habitat;
- or 5 metres of on-site linear habitats such as hedgerows.
Note: Evidence in the form of photos will be required to show this. For details, please see: Local List.
- Biodiversity gain sites. Planning permission for development which is for the purpose of achieving a 10% net gain in relation to another development.
- Householder applications. Applications made by householders as defined within Article 2(1) of the Town and Country Planning (Development Management Procedure) (England) Order 2015.
- Self-build and custom build applications. An exemption applies to this type of development when it meets all the following conditions:
- consists of no more than 9 dwellings
- on a site that has an area no larger than 0.5 hectares
- consists exclusively of dwellings that are self-build or custom housebuilding as defined in Section 1(A1) of the Self-build and Custom Housebuilding Act 2015.
Note: The majority of development will still need to include a Species Enhancement Statement (SES) to include features for faunal species. This requirement is separate to BNG.
What information you need to submit with your application
Planning applications which are not exempt from BNG must be accompanied by the latest minimum national information required in relation to BNG. This can be viewed within Paragraph: 011 Reference ID: 74-011-20240214 of the Biodiversity Net Gain Planning Practice Guidance.
In addition to the minimum national information requirements, Calderdale Council as Local Planning Authority (LPA) also requires further information to assist the consideration of BNG as part of the determination of the planning application. The level of information required for validation and determination will depend on the scale and type of the planning application.
For more guidance, refer to our Local List or the Biodiversity Net Gain SPD.
When you can use the Small Sites Metric (SSM)
Natural England has made a SSM for use on smaller development sites. For the purposes of this SSM, such sites are defined as:
For residential
Where the number of dwellings to be provided is:
- between one and nine inclusive (on a site having an area of less than one hectare);
- or not known (a site area of less than 0.5 ha).
For non-residential
where the floor space to be created is less than 1,000 square meters OR where the site area is less than one ha.
It is not possible to use the SSM on all small sites. This criteria must also be met to use it:
- Where only the habitats available in the SSM are present on-site.
- Where no priority habitats are within the development site.
- Where no statutory protected sites or habitats are present.
- Where no European protected species are present.
The SSM must be completed by a "competent person" as defined by page 6 of the Small Sites Metric (Statutory Biodiversity Metric) User Guide (GOV.UK).
Users of the SSM should be competent in identifying:
- habitats present on site (pre-development);
- management requirements for habitats to be created or enhanced within the landscape design (post-development).
Note: The developer is responsible for selecting the competent person for completing the SSM. If a SSM is submitted where a Statutory Metric Calculation Tool is required this may result in your application not being validated by the LPA.
BNG Policy
Local Plan Policy
Policy GN3 'Natural Environment' in the Calderdale Local Plan (adopted March 2023) requires developments to:
g) Design-in wildlife and provide appropriate management, ensuring development follows the mitigation hierarchy and achieves measurable net gains in biodiversity in accordance with the most up to date national and local guidance.
Biodiversity Net Gain Supplementary Planning Document (SPD)
This builds on and adds detail to policies in the Local Plan. We have made this to guide those who seek planning permission for development through the process of complying with national and local policies.
The Local Planning Authority (LPA) will expect all applications to conform to National Guidance and to all information set out within the BNG SPD. Failure to do so may result in delays to the planning application. The SPD provides guidance on (but not limited to) the following:
- Good Practice Principles.
- Information required for validation and determination.
- Strategic Significance.
- Monitoring and Reporting.
- Significant on-site gains.
- Demonstrating on-site delivery of BNG.
- Off-site delivery of BNG.
The BNG SPD went through public consultation between 23rd October and 20th November 2023 and will be formally adopted in 2024. It will be published here in due course.
Pre-application advice
This is available and encouraged. Avoidance of impacts on biodiversity and the delivery of a 10% net gain is important to think about when selecting a development site and during the design of the proposal.
There are some situations when providing the 10% BNG may be more complex. Having pre-application advice in these situations may help, in particular, where your application:
- Is in a Site of Special Scientific Interest (SSSI) or Local Wildlife Sites (LWS).
- Is located where irreplaceable habitats are present. (May require the relevant date for calculating the pre-development biodiversity value to be set as an earlier date.)
- Is located where habitat damage or removal has taken place.
- Is to be a phased development.
With your request, please include:
- Your name, address and contact details.
- A map showing the location of the proposal.
- Details of the nature of your proposal.
- A completed Statutory Biodiversity Metric of the baseline habitats. For details of how to do this, visit: Biodiversity Net Gain (GOV.UK).
Note: Our Planning Service provides this for a fee. please see: Planning service charges.
Long-term Monitoring Fees
A Habitat Management and Monitoring Plan (HMMP) will be required for significant on-site net gains and all off-site net gains for a minimum of 30 years.
In order for the LPA to audit the delivery of Biodiversity Units (BUs) approved within the Biodiversity Gain Plan and check that the management plan is being complied with, Monitoring Reports will be required for all on-site significant net gain and all off-site net gain. The schedule and methodology for monitoring should be included within the HMMP in accordance with the intervals set within Calderdale's BNG SPD.
A monitoring fee will be taken upon approval of a Biodiversity Gain Plan by the LPA to cover the long-term costs of the LPA to review reports and undertake site visits over the 30-year period. The fees will be proportional depending on the scale of the site and the complexity of the habitats to be delivered. Any non-significant on-site gains will not incur a monitoring fee.
Monitoring fees will be published upon adoption of the BNG SPD in 2024.
Note: A monitoring fee will not be taken when purchasing BUs directly from the Council as this will be built into the cost per unit charges. If you are purchasing off-site BUs from a habitat bank which already has a legal agreement in place (whether this is with Calderdale MB Council, another council or a Responsible Body) an additional monitoring fee may not be required.
Fees will be index linked and reviewed regularly.
Calderdale Council Habitat Bank
It is the ambition of the Council to enhance biodiversity on Council owned land by operating as a Habitat Bank selling Biodiversity Units. The Council have been operating this approach since 2021, however, due to the specific requirements of the Environment Act, from 2024 all off-site biodiversity Units must be legally secured and registered on the National Biodiversity Gain Sites Register. In order to do this the Council must work with a separate Responsible Body to secure their habitat bank land. Work is currently underway to enable this, but the Council is currently closed to applications for offsetting in the following circumstances:
- Major applications which were received on or after the 12th February 2024.
- Minor applications which were received on or after the 2nd April 2024.
Applications which meet the above criteria will need to source off-site Biodiversity Units either on their own land, on a third parties land or from a Habitat Bank.
For major applications submitted before the 12th February 2024 and minor applications submitted before 2nd April, the Council may accept a contribution for Biodiversity Units (subject to offsetting being approved for the proposal). All contributions for offsetting BNG on Council land will require a Section 106 Agreement.
The cost per Biodiversity Unit is £27,500 which is broken down as follows:
| BNG service | Price |
| Biodiversity Unit creation/management fees | £22,000 |
| Cost of site assessments and HMMP | £2,200 |
| Long-term monitoring and reporting | £2,200 |
| Strategic biodiversity delivery | £1,100 |
Note: The Council will not accept Biodiversity Offsetting contributions for the loss of any sort of Watercourse Units or habitats that it cannot provide on its land holding.
Calderdale Habitat Bank Mapping
The Council has undertaken preliminary mapping of its land holdings potential to be included with a Habitat Bank. This will be updated as baseline surveys are undertaken, management plans produced and legal agreements set up to indicate the type and number of Biodiversity Units available. This can be viewed on our Biodiversity and Geodiversity map under "Biodiversity Net Gain Potential Sites".
For queries or more about sites highlighted on the map, please email: biodiversitynetgain@calderdale.gov.uk.