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Phosphates on the Somerset Levels and Moors Ramsar Site

Information on Phosphate Mitigation in Mendip and progress on solutions.

Parts of the Somerset Levels and Moors are designated as a Special Protection Area (SPA) under the Habitat Regulations 2017 and listed as a Ramsar Site under the Ramsar Convention which protects wetlands. These are sites of national and international significance for wildlife.  On 17 August 2020, Mendip and other Somerset authorities received a letter from Natural England about the high levels of phosphates in watercourses affecting the condition of the RAMSAR site. 

Natural England have advised that, in light of the unfavourable condition of the Somerset Levels and Moors Ramsar Site, before approving a planning application that may give rise to additional phosphates within the catchment risk area, competent authorities should undertake a Habitats Regulations Assessment (HRA). In practice, this means the HRA for housing and other applications in the risk area will need to include a phosphate loading calculation and measures to reduce phosphates in water runoff and sewerage so it becomes 'nutrient neutral'. This is explained in the Natural England summary: Icon for pdf Nutrient Neutrality - non technical summary [138.83KB].  A planning application will only be able to proceed to a positive recommendation if the proposed development is phosphate neutral or there is identified mitigation that can be secured.

Risk Maps showing where Phosphate Mitigation is required

An overview map of the areas in Mendip subject to phosphate mitigation requirements can be found here: Icon for pdf Map of Area of Risk [306.66KB] 

The requirements will vary depending on whether you need to mitigate for foul water, surface water or both sources. The shaded area shows the surface water area of risk together with specific  Water Recycling Centre catchments where  either  (a) sewage treatment impacts on the RAMSAR but there is no mitigation for surface water or (b) the sewage treatment does not impact on the RAMSAR but there remains a need for surface water mitigation.

Surface and Water Recycling catchments can be viewed in detail on Mendip Maps 

Go to 'Environment and Planning' in the drop-down list of map categories and select both 'Somerset Levels and Moors Ramsar Risk Area' and both 'Indicative WRC linked to RAMSAR' and 'Indicative non-RAMSAR WRC'.  

Affected Development:

The types of development subject to phosphates related HRA within the area of risk include:

  • New residential units - including tourist accommodation, gypsy sites /pitches
  • Commercial developments - where overnight accommodation is provided
  • Agricultural Development - additional barns, slurry stores etc. where it is likely to lead to an increase in herd size
  • Anaerobic Digesters
  • Possibly some tourism attractions

Further information on how this will affect your application for planning permission or discharge of conditions, including how the Council will deal with your application and the additional information required can be found here: Apply for Planning Permission - Phosphates and the Somerset Levels and Moors Ramsar Site 

    Phosphate Budget Calculator

    The phosphate budget calculator can be used on proposed developments across Somerset. It will provide a transparent and rapid calculation of net phosphate loading from developments, including phosphate offsetting calculations for on or off site locations. The calculator has been approved by Natural England and it can therefore be used to provide a standardised and transparent decision making tool for the Local Planning Authority and Developers.  Please contact the council for advice on the use of the calculator for loadings for just surface water or sewerage.

    Developers should use this calculator to show the level of phosphates where a development will generate loadings for foul flows and surface water.  This should be part of the package of information to support the planning application.  The calculator will remain under constant review and updated to ensure that it reflects any data changes - see Icon for pdf calculator updates [39.71KB].

    A video has been prepared which provides a step by step guide to help you use the calculator.

    Phosphorous Budget Calculator 

    Please contact the council for advice on the use of the calculator where a single loading (surface water or sewerage) is required.

    View the Phosphates Guidance Video

    Wessex Water Maps of WRC catchments and nutrient permit information - see 'developers' tab

    Somerset Phosphate Strategy

    Phosphate Mitigation Solutions Report

    Since receipt of Natural England's 2020 letter, the four Somerset district councils and Somerset County Council have been working hard to clarify the position on affected planning applications, lobby government and stakeholders and develop a phosphate strategy for Somereset.

    The five Somerset Local Planning Authorities jointly appointed Royal Haskoning DHV (RHD) in March 2021 to develop a Phosphates Management Strategy to enable future development to take place within the catchment of the Somerset Levels and Moors Ramsar Site.

    The report provides an overview  of phosphate mitigation solutions, potential costs, effectiveness and feasibility. It also provides estimates of the scale of mitigation required to meet current planned housing growth.

    The report includes feedback from stakeholder workshops held in August  2021 and input from Natural England and Environment Agency. See video of the consultant workshop (Sept 2021

    Icon for pdf Somerset Phosphate Mitigation Solutions Report [3.84MB]

    The solutions report forms part of work to develop a Somerset wide Phosphate Strategy.  Joint work is continuing to develop a strategic approach to solutions such as catchment actions plans and a register of nature-based schemes. This will build on the recommendations and evidence in the solutions report.  However, the strategic solution is still being worked on and will not be available for some time.

    Scope and Timescales on the strategy are set out in the Icon for pdf Phosphates Position Statement 29.11.2022 [77.78KB].

    Natural England Letters and Government Advice

    Natural England released a new national approach, tools and guidance on nutrients mitigation on 16th March 2022.  It has been agreed the existing Somerset approach and phosphate mitigation calculator should continue to be used while this is evaluated. The Government announced in March 2022 a package of support for impacted areas and a policy statement for nutrients on 20th July 2022. Further details are contained in the Icon for pdf chief planners letter [164.51KB].

    Wessex Water Information

    Legal Advice

    The Council has sought legal advice from Counsel on some key issues. This includes advice sets out that 'pre-commencement' conditions relating to affected developments within the catchment area, cannot be discharged until an HRA has been undertaken. This approach has been confirmed nationally.

    The Council and Natural England have also agreed advice around 'permitted development'.

    Further information and FAQs

    The Planning Advisory Service (PAS) are supporting planning authorities impacted by nutrient mitigation.  The national PAS FAQ on neutrality issues can be found here.

    If you have any questions in the meantime, please contact  

    Press Releases 

    Icon for pdf Mendip phosphate newsletter no 1 [281.25KB]

    National action needed to address phosphates issue

    Mendip moves to protect precisous Levels and Moors

    Council leaders seek Government support on phosphate requirements

    Councils publish phosphate calculator