Nutrient Neutrality information for developers

This webpage contains a summary of the information needed to accompany applications which are affected by nutrient neutrality.

All the information on this webpage should be read in conjunction with the Natural England Advice set out below.

March 2024 - Updated Natural England Nutrient Neutrality Calculator

Natural England have updated their guidance on nutrient neutrality.  This includes a new nutrient neutrality calculator which should be used in nutrient assessments, submitted with planning applications.

For planning applications which are waiting determination, the nutrient budgets should be calculated using the new methodology.

Please note the 2024 calculator supersedes the 2022 calculator.

View and download the 2024 Nutrient Neutrality Calculator

March 2022 - Previous Natural England Methodology

Natural England Nutrient Neutrality Methodology March 2022 [pdf] 964KB

Stodmarsh Nutrient Budget Calculator March 2022 [xlsx] 4720KB 

Stodmarsh Nutrient Budget Calculator Guidance [pdf] 797KB

The 2022 updated methodology supersedes the November 2020 Natural England Advice [pdf] 1421KB.

What information do I need to submit with my application?

If your application site is located in the Stour catchment and your development is required to demonstrate nutrient neutrality you will need to submit the following information:

• Nutrient calculations undertaken in accordance with the methodology set out in the related (Natural England) (NE) Advice [pdf] 964KB.
• Where the calculations identify a net increase in nutrients, details of how it is intended to mitigate the impact of the additional nutrients generated.

Once all this information has been submitted to the council, we will conduct an Appropriate Assessment to determine whether the development proposal demonstrates nutrient neutrality.

Nutrient calculations

In order to calculate the total nutrients generated by a development, Natural England has prepared a calculator for public use.

Download the Natural England Nutrient Budget calculator [xlsx] 2663KB

To assist with using the calculator, the council has set out average occupancy rates for specific types of developments, such as flats or hotels.  These values can be used in the nutrient calculations.

Any applicant wishing to deviate from these values will be required to provide robust evidence in support of their application in order to justify their approach.

Non-mains drainage

For development proposals that connect to non-mains drainage, information about the type, location and efficiency of Package Treatment Plant (PTP) must be provided, together with details of the monitoring and maintenance of the PTP(s).

Evidence to support the PTP efficiencies could include:

• Test result documents from the lab
• Measured effluent concentrations from real world applications

What counts as mitigation?

Mitigation, for nutrient neutrality, acts to reduce the overall nutrients released from development.

Examples of mitigation include:

• Wetlands
• Sustainable Urban Drainage Systems (SUDs)
• Taking land out of agricultural land use

For any mitigation proposal, information should be given to show the design, location and efficiency of any mitigation and how this results in the development achieving nutrient neutrality.

Wetland mitigation

The effectiveness of wetlands at removing nutrients is highly dependent on the design and maintenance.

Natural England sets out that wetlands must:

• Have a permanent input of water
• Have a detailed design of the proposed wetland to accompany the planning application
• Calculate wetland specific Nitrogen and Phosphorus removal rates
• Include details of the monitoring and maintenance of the proposed wetlands in perpetuity (minimum 80 years)

In partnership with the Rivers Trust and the Constructed Wetland Association, Natural England has prepared a Constructed Wetland Hub. The hub contains information about constructed wetlands. Natural England have also produced a Wetland Framework which sets out the types of information that should be provided for the development proposals including wetlands as nutrient mitigation.

View the Constructed Wetland Hub and Wetland Framework

(Please note the hub is still currently under construction and will be updated with relevant information, when this information is available).

SuDS

Sustainable urban drainage systems (SuDS) simulate the natural drainage processes in urban environments to reduce surface water flooding.  SuDS can also provide a form of nutrient mitigation.

CIRIA has worked with Natural England to prepare guidance about the nutrient removal associated with SuDS. This guidance is set out in:

• C808F: Using SuDS to reduce phosphorus in surface water runoff
• C815F: Using SuDS to reduce nitrogen in surface water runoff

Please use the links above to access the relevant SuDS advice from the CIRIA website.

Borough Mitigation Strategy & strategic nutrient mitigation

For development proposals, which can’t mitigate on-site, the Council is preparing a borough Mitigation Strategy. This Mitigation Strategy will be a series of short, medium and long term solutions.

Following an announcement by the Leader of the Council in October 2023, work on the Mitigation Strategy is currently on pause.

Further information is out on our main nutrient neutrality webpage.

Should you choose to submit an application that relies upon strategic nutrient mitigation, please continue to prepare the nutrient calculations and provide these together with any additional information required (in accordance with the guidance above) and submit these as part of the planning application. Please also confirm in a covering letter that you intend to wait for strategic nutrient mitigation.

Stodmarsh Operational Statement - March 2022

The Council has adopted an Operational Statement in March 2022 which sets out that the Council will work in collaboration with the Environment Agency, Kent County Council and Natural England towards the delivery of strategic wetlands.

View the Stodmarsh Operational Statement [pdf] 905KB.