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Nutrient mitigation

Nutrient mitigation

Excessive nutrients (principally nitrogen and phosphates) in the Solent’s European sites are causing eutrophication, leading to an increase in algae growth. This has an adverse impact on the habitats and species within the European nature conservation designations sites in and around the Solent (including the Solent and Southampton Water SPA) to which the Habitat Regulations apply.

Following recent case law, Natural England has advised that there is a likely significant effect on the Solent’s European sites due to the increase in wastewater from new housing. It has also advised that any development proposed through any planning application providing overnight accommodation which would discharge into the Solent would also be likely to cause a significant effect. There is uncertainty as to whether the increase in wastewater from new housing in the Solent’s catchment will have an adverse impact on the Solent’s European sites.

Natural England recommends that the wastewater issue is examined within the Appropriate Assessment process undertaken by the National Park Authority.

For this reason, we are requesting the submission of a Nitrate Mitigation Checklist for any planning application for a net increase in dwellings or providing overnight accommodation.

Natural England has published updated guidance on the issue of nitrates from new development affecting the internationally-protected Solent habitats. This updated information is available to download from this website and comprises:

Solent nutrients guidance – Version 5, June 2020

Solent nutrients advice – non-technical summary, June 2020. This includes a Frequently Asked Questions section in Annex A.

Nitrogen budget calculator: This spreadsheet standardises nutrient budget calculations

Applicants are advised to review this guidance in preparing their applications. We have also published a map illustrating the respective water treatment catchment areas for the National Park area to indicate the areas of the New Forest affected by the issue. This is available to download on the right hand side.

National Park Member


'Read our guidance notes before applying to save yourself time in the long run.'

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