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Nutrient Neutrality

Nutrient Neutrality

Background Information

In 2019 and 2022, Natural England issued guidance to all Local Planning Authorities raising concerns about the level of nutrients in protected sites. Planning decisions must therefore take account of this concern under Habitat Regulation legislation.

The protected sites of the Solent and River Itchen are internationally important for their wildlife. These sites are vulnerable to elevated nutrient levels. There are many types of nutrients, however the ones which require mitigation are nitrogen and phosphorus. An increase of such nutrients can cause a process called eutrophication. This is where increased nutrient levels cause excessive growth of certain plants, such as green algae, which has a detrimental impact upon protected habitats and bird species. Sources of nutrients include agriculture such as fertiliser run off, and wastewater outputs from new development.

Residential development, including new homes and other uses that provide overnight accommodation and tourism attractions, can potentially have an adverse impact on the protected sites of the Solent and River Itchen because of the wastewater they generate.

For the types of new development listed above, the Authority will need to undertake a Habitats Regulations Assessment of planning applications to be satisfied that the proposal will not have any adverse impact on the protected site or sites.

These development proposals will need to be nutrient neutral to avoid detrimental harm to the ecology of the Solent and River Itchen. This means that a development is not adding any further nutrients into the natural system, and therefore a neutral balance is achieved. A Nutrient Budget will need to be prepared and submitted to demonstrate this. Natural England has provided advice on how to do this.

The advice affects three river catchments in the South Downs National Park: the East Hampshire Catchment and Western Streams Catchment that drain towards the Solent SPA, SAC and Ramsar designated sites, and the Itchen Catchment, that drains towards the River Itchen SAC.

Natural England have produced a summary guide and further information which is included below, If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email enquiries@naturalengland.org.uk

What you need to know

What you need to do depends on which river catchment your development is within.

You can find out which river catchment you are in by going to the Environment Agency website, zooming in to the site of your development and clicking. This will then tell you which catchment you are within.

East Hampshire Catchment

You will be required to demonstrate that your development is nitrogen neutral before permission can be granted.

Before your planning application During your planning application Mitigation options
  • Prepare the nutrient budget calculator. This must be submitted as part of your application.
  • For the East Hampshire Catchment, the correct calculator can be found here.
  • If the calculator shows a positive nitrogen calculation, you will be required to demonstrate this is mitigated before planning permission can be issued.
  • Investigate your mitigation options in preparation for your submission.
  • You may find these documents useful:
  • The case officer will assess your calculation alongside Natural England. There may be points of clarification for you to answer.
  • If you have not done so already, please inform your case officer how you intend to mitigate the amount of nitrogen the development will create.
  • Please note that under the Habitat Regulations a Planning Authority cannot lawfully approve an application where mitigation has not been demonstrated.
  • If your calculator is accepted and suitable mitigation is secured, and provided all other matters under consideration for your application are acceptable, the case officer will write an Appropriate Assessment which is a record of the mitigation.
  • On-site Package Treatment Plant – it is possible to remove nutrients on-site using equipment.
  • The SDNPA need to monitor that the equipment is working as it should over a 125 year period and there are monitoring fees associated with this approach – please discuss with your case officer.  Please note that if on-site treatment and a third party site are used, monitoring fees still apply.

 

Western Streams Catchment (The Ems, The Lavant, and Bosham Stream)

You will be required to demonstrate that your development is nitrogen neutral before permission can be granted.

Before your planning application During your planning application Mitigation options
  • Prepare the nutrient budget calculator. This must be submitted as part of your application.
  • For the Chichester Catchment, the correct calculator can be found here
  • If the calculator shows a positive nitrogen calculation, you will be required to demonstrate this is mitigated before planning permission can be issued.
  • Investigate your mitigation options in preparation for your submission.
  • You may find these documents useful:
  • The case officer will assess your calculation alongside Natural England. There may be points of clarification for you to answer.
  • If you have not done so already, please inform your case officer how you intend to mitigate the amount of nitrogen the development will create.
  • Please note that under the Habitat Regulations a Planning Authority cannot lawfully approve an application where mitigation has not been demonstrated.
  • If your calculator is accepted and suitable mitigation is secured, and provided all other matters under consideration for your application are acceptable, the case officer will write an Appropriate Assessment which is a record of the mitigation.

     

    Itchen Catchment

    You will be required to demonstrate that your development is nitrogen and phosphorus neutral before permission can be granted.

    Before your planning application During your planning application Mitigation options
    • Prepare the nutrient budget calculator. This must be submitted as part of your application.
    • For the Itchen Catchment, the correct calculator can be found here
    • If the calculator shows a positive nitrogen and/or phosphorus calculation, you will be required to demonstrate this is mitigated before planning permission can be issued.
    • Investigate your mitigation options in preparation for your submission.
    • You may find these documents useful:
    • The case officer will assess your calculation alongside Natural England. There may be points of clarification for you to answer.
    • If you have not done so already, please inform your case officer how you intend to mitigate the amount of nitrogen/phosphorus the development will create.
    • Please note that under the Habitat Regulations a Planning Authority cannot lawfully approve an application where mitigation has not been demonstrated.
    • If your calculator is accepted and suitable mitigation is secured, and provided all other matters under consideration for your application are acceptable, the case officer will write an Appropriate Assessment which is a record of the mitigation.

       

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