Nutrient pollution, nutrient neutrality and the planning process

Your nutrient neutrality statement should be concise, only providing the key information outlined in this note.

When do you need to provide a nutrient neutrality statement?

Nutrient neutrality statements will be required for all qualifying development within nutrient sensitive catchments. As nutrient neutrality statements are a requirement for validating planning applications, we advise that they are completed at the start of the process so that they are ready to submit alongside the other necessary information.

Qualifying development

The requirement for nutrient neutrality only applies where the increase in nutrient loading arising from the development is significant. This includes:

• any form of development that increases overnight stays within the catchment
• some commercial development that either attracts large numbers of people into the catchment (such as a tourist attraction) or where there is a significant discharge into the catchment for example from an industrial process
• development which results in the intensification of agricultural practices, such as an additional cattle barn

Development that increases overnight stays in the catchment may comprise permanent residential development, gypsy and traveller development, care homes, nursing homes, tourist accommodation including both permanent and temporary campsites and hotels. We refer to this as ‘qualifying’ development.

Catchment areas

The requirement for nutrient neutrality only applies to qualifying development within a nutrient sensitive catchment area.

There are a total of five nutrient sensitive catchment areas in Dorset Council’s administrative area. These are:

• Poole Harbour catchment
• River Avon catchment
• Somerset Levels and Moors catchment
• Chesil Beach and the Fleet catchment
• River Axe

The catchment areas are defined on maps prepared by Natural England which can be accessed on our webpages (applicants should also refer to the mapping prepared by Wessex Water which shows where treated effluent from wastewater treatment works is discharged).

What needs to go in a nutrient neutrality statement?

Site location and description of the proposed development

The nutrient neutrality statement must include maps showing the location of the proposed development site (scaled at 1:1250) and a block plan showing the application site boundaries (scaled at 1:500).

The proposed development must be clearly and precisely described referencing the relevant Use Class from the Use Classes Order where appropriate. If new homes are proposed, the statement must also specify:

• the number of new homes proposed
• the size and type of new homes proposed
• the tenure mix of the new homes (specifically the number of affordable homes as defined in the National Planning Policy Framework)
• the date when you expect the first home to be occupied
• for large sites only, detail of any phasing arrangements for the delivery of homes

Nutrient budget calculation

Following Natural England’s guidance, you should use the relevant nutrient budget calculator for the catchment area where the development is located to determine the nutrient budget. 

Calculators for each nutrient sensitive catchment can be accessed from the web pages relating to the relevant catchment. Each calculator takes the form of an excel spreadsheet.

For the nutrient calculations for each development proposal, the following information will be needed:

• details of when the development will be first occupied
• the proposed numbers of homes
• how wastewater effluent will be treated (there are options to select water company treatment works as well package treatment works and septic tanks)
• details of the ‘operational catchment’, ‘soil drainage type’, ‘annual average rainfall’ and confirm whether the site is within a ‘nitrate vulnerable zone’ (all of this information can be accessed using links provided in the instructions section of the calculator spreadsheet)
• using Natural England’s guidance, details of the existing land use and site area (where there is more than one land use this will need to be inserted along with the corresponding site area for each part of the site)
• using Natural England’s guidance, details of the future land use and site area (where there is more than one land use this will need to be inserted alongside the corresponding site area for each part of the site)
• details of Sustainable Urban Drainage Systems where available

Occasionally it may be necessary to amend some of the standard value inputs to take account of the proposed development (for example seasonal campsites, or other residential uses where there might be some limit or restriction on occupation). The accompanying statement should specify when standard values have been amended and provide clear evidence to justify the values used in the nutrient budget calculation.

Please save a copy of the excel spreadsheet that you create and send this electronically as part of your nutrient neutrality statement. Separately and alongside the excel spreadsheet, please also insert ‘screen shots’ of each stage of the nutrient budget calculation to insert within your nutrient neutrality statement.

The calculator should provide a nutrient budget for the proposed development. This may include a pre 2030 and post 2030 budget after the nutrient pollution standards take effect.

Proposed nutrient mitigation strategy

Referring to the nutrient budget calculation derived from the relevant calculator, the nutrient neutrality statement must detail a strategy setting out how the nutrient impacts from development will be mitigated. 

In some instances, particularly when applicants are seeking to rely on third party credits (including those from Natural England mitigation projects), it may not be possible to provide a provisional nutrient credit certificate as part of the nutrient neutrality statement when the planning application is submitted. In these cases, the applicant and development management case officer will need to work together to gather any further information on the mitigation measures over the course of the planning application process. The development management case officer may also need to consider whether it would be appropriate to apply a restrictive pre-commencement condition requiring the delivery of mitigation as part of the planning decision.

The specific approach to securing mitigation is likely to vary between applications, but in all instances, we will require that the mitigation is delivered prior to development commencing.

There are several different options, for providing mitigation including:

• on-site, or through other land in the ownership of the developer
• through an agreement with an accredited third-party mitigation provider
• through an agreement with Dorset and BCP Councils when acting as mitigation providers

In all instances, the mitigation will need to be secured in perpetuity (for the purposes of permanent residential development the council takes this as being 80 years) through the necessary legal agreements or planning conditions. The package of mitigation measures for any development proposals may comprise credits relating to both permanent and temporary mitigation projects.

We have prepared some separate guidance on securing Dorset and BCP Councils mitigation credits, mitigation credits from other third-parties and some of the issues that will need to be considered when delivering mitigation on site or on other land in your control.

This section of our webpages provides more information on mitigating nutrient pollution through credits obtained from a mitigation provider.

Mitigation credits delivered by Dorset Council

We have been awarded Local Nutrient Mitigation Fund grant to deliver nutrient mitigation schemes in Poole Harbour catchment. We will also explore opportunities to deliver mitigation in other nutrient sensitive catchments in our area, including within the Somerset and Wiltshire Councils who have also separately been awarded Local Nutrient Mitigation Fund grant. 

This section starts with an explanation of the process for securing mitigation projects from Dorset Council mitigation schemes.

The cost of Dorset Council credits

Credit prices will be set fairly with the aim of encouraging delivery of sustainable development in accordance with our development strategy. The price of credits will vary and will take account of:

• the costs of delivering the mitigation project (this may include investments to acquire land and to install plant and infrastructure)
• the ongoing costs connected with the ensuring that the mitigation project remains effective in perpetuity 
• administrative and legal costs
• the price of mitigation credits in the wider credit market

The steps for making an application for credits are outlined next.

Temporary nitrogen mitigation credits for the Poole Harbour catchment

As of January 2025, we are inviting expressions of interest for the purchase of temporary nitrogen mitigation credits in the Poole Harbour catchment. These credits are only likely to be of interest for development in Dorset Council area because wastewater treatment plant in the BCP Council area will not be subject to new permitting requirements from 1 April 2030.

If you are interested in securing temporary nitrogen mitigation credits for the Poole Harbour catchment from us you will need to make your application within a defined window. We will be accepting initial expressions of interest for these credits between 8 January 2025 and 8 February 2025. There are more details on this elsewhere on our website.

Securing credits from a mitigation project delivered by Dorset Council

At present (January 2025) the councils are not able to offer any permanent mitigation credits. We currently only inviting expressions of interest for temporary nitrogen mitigation credits for the Poole Harbour catchment area. Both councils are still working on investing Local Nutrient Mitigation Fund grant from government to secure permanent nitrogen mitigation projects in the Poole Harbour catchment. Earlier web pages that list ‘accredited’ mitigation schemes will be regularly reviewed and updated with details of credits as and when they become available.

This page sets out the process for making an application to secure mitigation credits from a project delivered by the council. 

Applications for credits can be made by:

• an individual
• a housing developer of any size
• a consultant working on behalf of an individual or a developer

To apply to buy credits the development proposal must fall within the definition of ‘qualifying development’ and be within the same catchment area as the mitigation project that is the source of the credits (it is not possible to mitigate the impacts from development located in one catchment area with a mitigation project delivered in another catchment area).

We suggest you investigate whether you will need nutrient mitigation for your development and how this will be secured before formally submitting your planning application. Your Nutrient Neutrality Statement should set out a nutrient budget and indicate how you intend to mitigate nutrient pollution from your development. We have set out the process of securing credits from us in more detail below.

Step 1

Screen whether your development proposals are located within any of nutrient sensitive catchments in Dorset and whether your development proposals fall within any of the categories of ‘qualifying development’. 

Assuming that you are seeking planning permission for qualifying development in a nutrient sensitive catchment the next step is to calculate how many credits are needed, based on a nutrient budget calculation for the development. Natural England have prepared calculators and guidance which allow nutrient budgets to be determined. We have also prepared separate guidance on water quality and nutrient neutrality statements, and determining how many temporary nitrogen mitigation credits you might require.

To calculate the nutrient budget for your development:

• begin by reading Natural England’s guidance on using the calculators
• use the relevant catchment calculator to determine the nutrient budget for your development

The calculator will give the annual total amount of nutrient (nitrogen and/or phosphorus) that requires mitigation in perpetuity. This will determine the amount of nutrient mitigation needed to offset the impact from the proposed development. The nutrient budget is expressed in kilograms (kg) for either total phosphorus (TP) or total nitrogen (TN) per year (yr). This has been abbreviated to: kg TP/yr or TN/yr. One nutrient credit is equivalent to one kilogram (kg) of nutrient pollution. Therefore, to mitigate one kilogram (kg) of nutrient pollution one nutrient credit will need to be purchased. To mitigate 2.75kg of nutrients 2.75 credits will be needed.

The nutrient pollution standards may affect nutrient loads from development after they take effect on 1 April 2030. The calculator will provide a pre and post-2030 nutrient loading figure in kg per year if there is a change in the budget after 2030. Details of both budgets will need to be provided in the nutrient neutrality statement that supports your planning application. We have prepared separate guidance on calculating temporary nitrogen mitigation budgets as part of our plans around sales of temporary nitrogen mitigation credits in early 2025.

At any point in time, temporary or permanent mitigation credits may be available depending on the mitigation projects which have been delivered. Temporary credits can be used to mitigate higher nutrient loading in the short term (i.e. pre-2030) before the nutrient pollution standards take effect. Permanent credits can meet both the short term (pre-2030) and long term (post-2030) loads from development.

You will also need to submit your nutrient budget calculations to us as part of your planning application (where required, we will not process your application unless you have provided nutrient budget calculations in a nutrient neutrality statement). We will review the calculations when assessing the planning application (this process will be simplified where we have already provided pre-application advice).

We will not accept credit applications unless your calculations have been checked and are confirmed by the council’s Environmental Assessment Team as part of the assessment of your planning application.

Step 2

You’ll need to provide the following information in your credit application:

• planning application reference number
• nutrient budget calculation that has been checked and confirmed by the council’s Environmental Assessment Team and Natural England
• assessed requirement for temporary and permanent mitigation credits
• applicants and agent’s names
• contact details

If you do not provide a checked and confirmed nutrient budget calculation, your credit application will be rejected.

Step 3

If your application is successful, we will contact you after the ‘window’ for expressions of interest closes to complete the sale of credits. There will be a streamlined payment process to purchase temporary nitrogen credits and anyone purchasing credits is expected to have the financing for the purchase in place. Planning permissions are likely to include a mechanism to ensure that work on implementing the permission does not begin until credits have been secured. This may take the form of a planning obligation or condition depending on the circumstances. 

Step 4

When you have received your final nutrient credit certificate, send a copy to our planning development management team (the team that is responsible for the sale of nutrient mitigation credits operates independently and separately from the officers who will be managing your planning application). Our development management team will confirm if you have met the terms of the nutrient mitigation conditions or planning obligations that were applied to the planning permission as part of any application to address the requirements of a planning condition.

When this has been confirmed, the housing on your development can be occupied.

Securing credits from a mitigation project delivered by a third party

Advice for mitigation providers

To meet the requirements of the habitats regulations we need to be satisfied that mitigation is achievable in practice at the point we take a decision on whether to grant planning permission.

We therefore need to be satisfied that a mitigation project delivered by a third-party will remain effective in perpetuity and that an applicant/developer has secured, or is capable of securing, the necessary credits before planning permission is granted.

We recommend that all third-party nutrient mitigation providers, within any of the catchments in Dorset Council area must enter a planning obligation with the council. During this process we will consider the suitability of the project to mitigate, the process for selling and tracking credits, and ongoing maintenance of the project to ensure that it remains effective in perpetuity. We will consider other arrangements for mitigation providers located outside Dorset Council area.

As part of the process of drawing up the planning obligation, third-party mitigation providers must seek and receive confirmation through Natural England’s Discretionary Advice Service that their mitigation project will be suitable and effective in perpetuity (a copy of the discretionary advice will be appended to the planning obligation).

We encourage mitigation providers to apply a similar approach and process to the sale of their credits as the council. We will maintain a record of the sale and availability of the credits relating to our own mitigation projects. Third party mitigation providers must maintain similar records and share details with the council on a regular basis and upon request.

Advice for applicants submitting a planning application which relies on mitigation credits from a third party

Applicants should outline in their nutrient neutrality statement how the impacts from their development will be mitigated. Whilst we would encourage third-party mitigation providers to follow a similar approach and process to the sale of credits, we cannot insist upon this (individual providers may also apply their own prioritisation policies for the sale of credits) but we will not enter into planning obligations or other agreements with mitigation providers unless certain terms have been satisfied (as outlined above).

Where available, we would encourage applicants to seek a provisional nutrient credit certificate from the third-party provider for submission with their planning application. In all instances we will need to be satisfied that the method for mitigating nutrients is achievable in practice before granting planning permission.

Securing mitigation credits from a Natural England mitigation project

There is currently one Natural England mitigation project within the Poole Harbour catchment. There are full details on applying for mitigation credits from this project on Natural England’s web site. The process for applying and securing credits is similar to the council's approach. Any queries relating to Natural England’s sale of credits should be directed to: creditsales.nutrientmitigation@naturalengland.org.uk.

Developer lead mitigation

If you intend to deliver nutrient mitigation for your development on the same site, or on other land in your control, you must discuss the suitability and effectiveness of your proposals with Natural England through their Discretionary Advice Service. Natural England’s advice should be appended to the nutrient neutrality statement that is submitted with your planning application.

You should provide details of how the mitigation will be secured and maintained in perpetuity. We are likely to require you to enter a planning obligation to secure the delivery of the mitigation project. Where delivering your own mitigation, you must draft terms of the planning obligation for submission with your planning obligation so that we can start to give it consideration early in the planning application assessment process.

This note provides guidance for third parties who intend to invest to deliver nutrient mitigation measures and sell mitigation credits, and those applicant/developers who intend to deliver mitigation within an application site or on other land in their control.

Third-party mitigation providers - Advice on developing and delivering mitigation projects

If you are considering investing to deliver a nutrient mitigation project in any of the nutrient sensitive catchments in Dorset Council area, we suggest you might want to consider some of the following issues.

The location of the proposed mitigation project

Initially, it is likely to be important to determine whether the project is located within the nutrient sensitive catchment area where you intend to sell mitigation credits (Natural England have mapped nutrient sensitive catchments and you should also refer to Wessex Water’s mapping information on the areas currently served by different wastewater treatment plant). It is not possible to deliver a project in one catchment to mitigate the impacts from development in another separate catchment. The impacts from development must be mitigated on a catchment specific basis.

Defining the proposed nutrient mitigation measures and completing a nutrient budget calculation

We recommend that you give consideration as to how reductions in nutrient flows into the nutrient sensitive catchment will be achieved. As part of this we suggest you evaluate options for reducing nutrient flows and select the most effective and efficient way of achieving the greatest reductions in flows. You must also consider when the measurable nutrient reduction will take effect. Any nutrient mitigation which is proposed on free draining chalk soils will need to consider the time associated with movement through the chalk up to 1 metre/year. In some circumstances Natural England will require hydrogeological studies to fully understand nutrient reduction and associated time lags.

As part of this process we also recommend that you give consideration as to whether the options which you might be reviewing would confer any wider benefits (including environmental: for example net gains in biodiversity, and social benefits: for example public access). As well as selecting the most effective and efficient projects for reducing nutrient flows we also encourage you to select those options which confer wider benefits.

Subject to site specific considerations, reductions in nutrient flows may be achieved through a change in land management, riparian buffers, wetlands, ditch blocking, upgrading package treatment plant or septic tanks. During this initial phase of selecting an approach to mitigation and project development, we also suggest that you attempt to fully investigate whether there are likely to be any issues or barriers connected with the delivery of your preferred mitigation measures (for example this could include legal restrictions, additional separate regulatory requirements for permitting etc.).

When preliminary proposals for the nutrient mitigation project have been drawn up, we also recommend that you complete a nutrient budget calculation. The nutrient budget calculation will allow you to determine the reductions in flows of nutrient into the nutrient sensitive catchment that could be achieved through the project. You may be able to rely Natural England’s calculators to complete this calculation, but depending on the site-specific considerations and the type of mitigation project which you are proposing, you may also need to complete more detailed specific investigations to precisely and accurately determine the nutrient budget. Completing several nutrient budget calculations to evaluate the effectiveness of different project options will help guide your overall approach.

Reviewing issues and constraints relating to a site and proposed mitigation measures

Following some initial screening and after reviewing the effectiveness of different options for mitigation, you will need to consider whether your preferred mitigation project conflicts, and is consistent, with any other issues and constraints relating to a site.

We suggest that you consider:

• agricultural land classification - land classed as the most versatile and productive land should normally be reserved for this purpose (agricultural land classifications are presented on Magic Map)
• protected areas (including National Landscapes, Sites of Special Scientific Interest, Special Areas of Conservation, Special Protection Areas, Ramsar wetlands and Marine Conservation Zones) – the proposed approach to mitigation may be inconsistent with these designations or it may complement them and provide opportunities to achieve wider environmental benefits
• heritage assets (including listed buildings, conservation areas, scheduled monuments, registered battlefields and registered park or gardens) – the approach to mitigate could have a damaging impact on the special character of the heritage asset, or it might provide an opportunity to achieve enhancement to its significance
• local and national planning policies

At this stage we also recommend that you seek to ascertain what consents or permissions may be required to deliver the proposed mitigation project (this may include planning permission or other environmental permits from the Environment Agency).

Defining the costs of delivering the mitigation measures

When you have a clearer idea of your proposals and the work required to deliver them, we suggest that you attempt to define or estimate as accurately as possible the costs of delivering your mitigation project.

Determining whether it would be viable to progress with the proposed mitigation project

Taking account of the costs of delivering the project, the nutrient budget calculations and the retail price which you set for the sale of credits we also recommend that you complete a viability assessment to guide your decision about whether to continue with investment in the project. Your viability assessment might take account of any opportunities for combining environmental payments (for example nutrient mitigation measures alongside Biodiversity Net Gain).

Seeking advice from Natural England through their Discretionary Advice Service

Before taking a final decision around investing to deliver a nutrient mitigation project, we strongly recommend that you approach Natural England through their Discretionary Advice Service for confirmation around the suitability and effectiveness of the proposed project.

Sale of credits

We have outlined our process for considering applications for nutrient mitigation credits for the nutrient mitigation projects which we deliver using Local Nutrient Mitigation Fund grant. Broadly this involves:

• applicant/developers formally applying for credits (we will require a planning application reference which means that applicants/developers will not be able to apply for credits until they have submitted their planning application)
• our consideration of their mitigation credit application
• issuing a decision on the outcome of the application – if successful we will issue a provisional credit allocation certificate where the applicant/developer pays a deposit to reserve the credits
• subject to the outcome of the planning application process, issuing a final credit allocation certificate following approval of planning permission and receipt of the outstanding fee for credits

For consistency, and effectiveness of the decision taking process, we suggest that you follow a similar approach when selling mitigation credits from your project.

Entering into a planning obligation with the council

After you receive discretionary advice from Natural England, we suggest that you approach us and open enquiries about entering an ‘overarching’ planning obligation for your mitigation project. There are advantages for you as a mitigation provider and for us when we take decisions on planning applications if both parties can agree suitable terms for an ‘overarching’ planning obligation for the mitigation project. When drafting the terms of the planning obligation we both must take account of the legal requirements in The Community Infrastructure Regulations (2010) (as amended).

Typically, an ‘overarching’ planning obligations for a nutrient mitigation project will provide a framework for:

• defining, tracking and recording the sale of mitigation credits
• ensuring that mitigation projects are secured and remain effective in perpetuity

Once in place an ‘overarching’ planning obligation gives us discretion to use restrictive pre-commencement planning conditions, rather than separate site-specific planning obligations, when taking decisions on planning applications where an applicant proposes to purchase credits that are derived from a mitigation project subject to the obligation. This streamlines the decision taking process on planning applications and is therefore also likely to be appealing to credit purchasers.

As part of the process of preparing a planning obligation, we will review the suitability and effectiveness of a mitigation project. We will not enter a planning obligation unless we are satisfied that the project is suitable and will operate effectively to reduce flows of nutrients. As part of our assessment of suitability and effectiveness we will ask for a copy of Natural England’s guidance, as provided through their Discretionary Advice Service, so that it can be incorporated into the planning obligation. It is unlikely that we will enter a planning obligation without discretionary advice from Natural England.

We can only enter planning obligations that relate to land in our administrative area, but there are other mechanisms which can also be considered as alternatives if you would like to put an ‘overarching’ agreement in place with us for a mitigation project located outside our administrative area. We suggest that you discuss these with us on a case-by-case basis as they arise.

Applicants/developers - Advice on developing and delivering mitigation projects for a specific planning application

Much of the advice around developing and delivering third-party mitigation projects is equally applicable to applicants/developers wishing to deliver their own mitigation alongside a specific planning application.

We recommend that applicants/developers work on their mitigation project whilst preparing their planning application so that details of the proposed mitigation are submitted alongside their planning application and nutrient neutrality statement. As part of preparing their planning application applicants and developers should seek discretionary advice from Natural England and must submit details of this with their planning application and nutrient neutrality statement.

It is likely that we will invite applicants/developers to enter into a planning obligation to ensure that their mitigation projects are secured and remain effective in perpetuity. We suggest that draft terms for the planning obligation are included in the planning application submission and that applicants/developers consider seeking pre-application advice from our planning and legal teams on the terms of the planning obligation before submitting their application.

Where a mitigation project delivered for a specific planning application delivers more credits than are needed for the development, we would welcome the opportunity of working with the mitigation provider to make surplus credits available to other development.