The earlier page introduced the issue of nutrient pollution in estuarine and freshwater habitat sites and the catchments of these sites which overlap Dorset. Habitat sites are defined in national planning policy as:
Any site which would be included within the definition at regulation 8 of the Conservation of Habitats and Species Regulations 2017 for the purpose of those regulations, including candidate Special Areas of Conservation, Sites of Community Importance, Special Areas of Conservation, Special Protection Areas and any relevant Marine Sites.
Habitat sites are designated and protected under the Conservation of Habitats and Species Regulations 2017 (as amended). When competent authorities (including local planning authorities) determine planning applications they must consider whether the development alone, or in combination with other plans or projects, is likely to have significant effects on a habitat site. Competent authorities do this through a series of assessments that include several distinct stages which all must be undertaken in accordance with the Regulations.
Where the competent authority cannot rule significant effects to a habitat site, they must complete an appropriate assessment of the implications of the development, alone or in combination with other plans and projects, taking account of the habitat site’s conservation objectives. If the appropriate assessment cannot rule out damage due to nutrient pollution, mitigation to reduce or eliminate the impact can be put in place.
The habitat sites of Poole Harbour, the River Axe, the River Avon, Chesil and the Fleet and the Somerset Levels and Moors are in an unfavourable condition because of nutrient pollution. In this context, unfavourable condition means a habitat site that is not being adequately conserved and/or where the results from monitoring show that important features of the site are not meeting all the mandatory site-specific targets. A habitat site’s condition must be taken into consideration when completing the assessments required by the Habitats Regulations.
Nutrient pollution and development
Nutrient pollution arising from additional qualifying development in the catchments of freshwater or estuarine habitat sites can worsen the site’s condition. If the habitat site is already assessed as being in an unfavourable condition it can make the site more sensitive to further nutrient pollution.
Where suitable mitigation measures are provided, additional harm arising from the qualifying development may be avoided. In this context suitable mitigation measures may comprise measures which prevent nutrient pollution directly or measures which reduce nutrient pollution from other sources that indirectly offset the impacts from a qualifying development.
Natural England’s advice on Nutrient Neutrality
On 16 March 2022, Natural England notified Dorset Council with their new advice for development proposals that may have the potential to adversely affect the condition of freshwater and estuarine habitat sites. This advice applied to the catchments of five habitats sites which together cover a large part of the Dorset Council area.
Natural England advice is to ‘carefully consider the nutrients impacts of any new plans and projects (including new development proposals) on habitats sites and whether those impacts may have an adverse effect on the integrity of a habitats site that requires mitigation, including through nutrient neutrality.’
The catchment areas and nutrients of concern within Dorset that Natural England’s advice relates to are:
- Poole Harbour – Nitrogen and Phosphorus nutrient pollution
- Somerset Levels and Moors – Phosphorus nutrient pollution
- River Avon – Phosphorus nutrient pollution
- Chesil and The Fleet – Nitrogen and Phosphorus nutrient pollution
- River Axe – Phosphorus nutrient pollution
Wessex Water’s Drainage and Wastewater Management Plan map (in particular the parts of the map relating to ‘Drainage Strategies’ and ‘Developers’) will help in understanding whether the wastewater treatment works which is likely to serve the development discharges into a protected habitat site.
Development can be considered Nutrient Neutral where it will not cause an overall increase in nutrient pollution affecting a specified habitats site. Natural England’s approach, and tools, for Nutrient Neutrality are based upon the latest evidence and include bespoke catchment specific calculators to help assess a nutrient budget for any new qualifying development. Nutrient budget calculations allow councils and developers to determine the level of mitigation required to offset the additional nutrient pollution expected from a particular development.
Further information on the guidance and tools from Natural England is available here: