What is nutrient neutrality: navigating Natural England stipulations

Understanding legislative drivers and opportunities

Nutrient neutrality is a relatively new, albeit well-known, concept amongst both developers and local planning authorities (LPAs) due to its impact on housing delivery across affected areas. As of November 2023, estimates by the Home Builders Federation (HBF)[1] suggested the number of new homes on hold across England due to the requirement to demonstrate nutrient neutrality had reached 150,000. This, of course, has significantly impacted on the ability of relevant LPA’s to meet their housing policy requirements.

In this article we present a brief definition of nutrient neutrality, the legislative drivers underpinning these requirements and key opportunity areas where the Delivery Associates Network can help through our network of Subject Matter Experts (SMEs).

What is Nutrient Neutrality?

Nutrient neutrality is defined by Natural England as:

“…a means of ensuring that a plan or project does not add to existing nutrient burdens within catchments, so there is no net increase in nutrients as a result of the plan or project.”[2]

‘Nutrients’ within this context refers to phosphates (P) and nitrates (N), both of which are regulated to limit their impact on water quality and ultimately biodiversity. Examples of practices or processes which are known to emit excess nutrients to watercourses are: industrial wastewater treatment works not performing to their permits, intensive agricultural production and excess fertiliser application, and mis-connected or failing domestic wastewater treatment plants (e.g., septic tanks).

Which developments does the Natural England advice apply to?

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; and

Tourist attractions where overnight accommodation is provided, or where the development would attract visitors from outside of the catchment area.

The contribution of catchment sources to the total additional burden is dependent on the catchment characteristics. Understanding this at the strategic scale is crucial, but does not impact on how one might seek to achieve localised solutions.

Legislative Drivers

In 2018, a landmark ruling by the European Court of Justice (CJEU) known as the Dutch N case set a new precedent in how the Conservation of Habitats and Species Regulations 2017 (as amended) (Habitats Regulations) was applied. In broad terms, this meant that the current trajectory of detriment, from nutrient loading to Habitats Sites [3], could no longer be sustained.

Natural England, as the Statutory Nature Conservation Body (SNCB) for England, issued letters to 32 LPAs in 2019, advising that a number of Habitats Sites were in ‘unfavourable condition’ due elevated nutrient levels impacting the aquatic-dependant habitats and species. In July 2022, this advice was extended to a further 42 LPAs, bringing the total to 74.

Natural England’s advice stipulates that LPAs should only approve applications for developments in affected areas where no reasonable scientific doubt remains that new developments will not give rise to adverse effects on the integrity of these protected sites (i.e., nutrient neutrality is achieved).

This advice was issued to LPAs responsible for managing development that falls within river catchments connected to the Habitats Sites deemed to be in ‘unfavourable condition’ due to nutrient pollution. This means that LPAs across England are affected differently, and some Local Authority areas will have a smaller proportion of their overall authority area affected than others.

What types of planning applications are affected?

All new full and outline planning applications;

Section 73 applications, to amend previous conditions that lead to increased floorspace or amendments to drainage arrangements;

Discharge of pre-commencement conditions

Reserved matters applications; and

Retrospective planning applications that result in nutrient loading.

What are the opportunities?

Some small-scale developments may be exempt from the application of nutrient neutrality requirements (e.g., meeting a de minimus criteria set by the relevant LPA). However, for all those ‘captured’ by the nutrient neutrality requirements, there is no statutory requirement for the LPA to intervene to find solutions to deliver neutrality. The responsibility is on the developer to do so.

Demonstrating nutrient neutrality must be done so in-perpetuity (minimum 80 years), and any mitigation proposals must follow the ‘mitigation hierarchy’: avoidance → minimisation → restoration → offsetting. If a net increase in nutrient burden is identified [4], then the option is to ‘design out’ the additional nutrient load or to mitigate.

Common project-scale mitigation schemes put forward by developers include:

On/off site land use change to land use types with lower nutrient leaching rates;

On/off site upgrades to private wastewater treatment systems;

Retrofitting water efficiency measures to existing housing; and

Nature-based solutions (wetland creation, riparian buffer strips etc).

Developer-led approaches, however, need to overcome challenges in terms of stimulating an adequate delivery of housing in the affected areas, specifically heavily urban areas where there is a lack of adjacent or local green space to offset any additional nutrient burden.

It may be preferable for an LPA to be proactive and drive a strategic approach if significantly impacted by the nutrient neutrality requirements. The challenges with this remain to be funding [5] and ultimately resource (e.g., technical support) to enable strategic delivery. A strategic approach including offsetting through the creation of a high-integrity environmental market (e.g., nutrient credit trading) also provides opportunities for ‘stacking’ – a concept which seeks to secure multiple benefits from a single intervention or site (e.g., co-production of Biodiversity [Net Gain] units and credits, Carbon Credits).

Some common strategic, council-led approaches to mitigation can include:

Producing additional Planning Policy Guidance;

‘Nutrient credit’ production through upgrades to currently owned council housing stock;

Council-owned nutrient credit schemes;

Fund the development of 3rd party nutrient credit scheme(s); and

Engagement with water companies to establish “stretch” targets.

The Delivery Associates Network is here to help you navigate this process confidently and to provide the best advice on strategic approaches to comply with nutrient neutrality requirements.

Josh Gittins is a Senior Scientist, working for Arup’s Climate & Sustainability Services based in Bristol. He specialises in the restoration and recovery of the natural environment, and how we can implement nature-based solutions across the built environment to better facilitate sustainable development. Josh has a diverse background, having worked across academia, consultancy and the public sector on environmental consenting and urban planning challenges straddling England and Wales.

If you have any questions on this topic, or would like support, please contact your Delivery Associate, or email DeliveryAssociatesNetwork@Arup.com

References and Footnotes

[1] Brookbanks Research Report (2023). The extent to which housebuilding contributes to nutrient pollution across watercourses in England.

[2] Natural England (2022). Nutrient Neutrality Principles. Natural England Technical Information Note TIN186.

[3] 'Habitats Sites' in the context of nutrient neutrality include Special Areas of Conservation (SACs), Sites of Community Importance, Special Protection Areas (SPAs), Ramsar sites including potential SPAs, possible SACs and proposed Ramsar sites.

[4] ‘Nutrient Calculators’ are the consistent approach used to determine the ‘baseline’ nutrient burden of a site and the associated Proposed Development, to understand if mitigation is required.

[5] The Local Nutrient Mitigation Fund (LNMF) currently being rolled out by the Department for Levelling Up, Housing and Communities (DLUHC), has created a new opportunity for LPAs to pursue catchment-wide strategic mitigation proposals to unlock residential development. The DLUHC has advised that £110 million is available in the form of grants of up to £10 million for the ‘lead’ LPA within affected catchments. This is being granted in “rounds” following bidding by LPAs for the funding. This includes £57 million already awarded to LPAs as part of “round 1”. Expression of interest for the second round of funding closed in April 2024.

In addition to the financial boost provided by the LNMF, the Levelling Up and Regeneration Act (LURA), which came into force in December 2023, introduced a statutory duty for water companies in England to carry out upgrades to wastewater treatment works (WwTW) to the highest technically achievable limits (TAL) by 2030 in nutrient affected areas