Nutrient Neutrality mitigation: The latest updates

Nutrient neutrality is a means of ensuring that a plan or project does not add to existing nutrient burdens so there is no net increase in nutrients as a result of the plan or project.

October 22, 2023

Nutrient Neutrality: the latest

In August 2023, the government announced it would make changes to the Habitats Regulations underpinning nutrient neutrality rules. 

It tabled an amendment to the Levelling Up and Regeneration Bill 2022–23 which would have required local planning authorities to assume that nutrients in wastewater from new developments would not adversely affect protected habitat sites.

The amendment was defeated in the House of Lords and not added to the bill.

Nutrient Neutrality: the background

Environmental conservation is a growing issue for developers.  Following an historic EU ruling in 2018 (the “Dutch N Case”), Natural England adopted nutrient neutrality as a means to tackle pollution of protected aquatic ecosystems. This means that developers of new housing schemes in affected catchment areas must now prove that they can mitigate any excess nutrient load created by wastewater generated from the build.

What causes excess nutrient loading?

Phosphorus and nitrogen are essential chemical elements that nourish plants and animals, supporting their growth. These substances, often referred to as 'nutrients,' play a crucial role in discussions about nutrient neutrality and water pollution. Phosphorus and nitrogen can enter water bodies in the form of compounds like phosphates and nitrates.

If there are too many nutrients in rivers and lakes, it can cause excessive growth of algae and plants. This can affect the quality of the water and damage local ecosystems.

The main sources of phosphorus and nitrates in rivers and lakes in the UK are faecal matter in sewage and fertilisers from agricultural land.

An infographic showing how excess nutrients end up in water courses
Sources of nutrient pathways to impact (Source: AWE International)

Will development be affected by nutrient neutrality?

Potentially, yes, if it is in one of the affected catchment areas, which include sites that are protected under local, national or EU regulations.

As of March 2022, this includes zones in a total of 74 local authorities across England. Carter Jonas have produced a useful list of affected LPAs, which are also illustrated on the plan below. Where these specified Habitats Sites are already impacted due to excessive nutrient levels, councils can only approve plans that will have no additional adverse effects on the protected area.  

A map of the UK showing the council areas affected by nutrient neutrality
Affected council areas across the country (Source: Savills in Architects Journal)

Which properties are affected?

The focus for planning is on housing developments that result in “additional overnight stays” which will generate additional wastewater.

What Is Included:

  • New Homes: Where there is a net increase in the number of dwellings, even by one house.
  • Tourism: This can include campsites with wastewater facilities, or sites where there is infrastructure for day visitors – highly relevant in some of these scenic locations.

What Isn’t Included:

  • Commercial: In general, developments such as schools and retail sites are deemed not directly contributing to drawing people into an area.
  • Property Extensions: Depending on how overall occupancy is calculated, extensions are usually excluded.

What is the planning process?

Developers or architects need to submit a proposal based on a Habitats Regulations Assessment, and where needed, a mitigation plan. “Nutrient Budget” calculators are available to quantify potential nutrient loading, and the degree of mitigation needed to prove nutrient neutrality.

How to achieve Nutrient Neutrality?

In principle, by reducing pollution from the site itself or finding ways to reduce impacts of other sources. This can be broken down into:

  • Building measures into your plans on site
  • Off-site reduction schemes (either via the LPA or a private landowner)
  • Purchasing nutrient credits through a trading scheme

Development plans can be considered ‘nutrient neutral’ where they can demonstrate that they will cause no overall increase in nutrient pollution affecting specified Habitats Sites.

Nutrient Neutrality mitigation measures 

If a developer finds that their development will produce additional nutrient load, they are obligated to take proactive steps to address the issue. They must either provide mitigation measures onsite to prevent nutrient pollution or ensure it is ‘offset’ elsewhere within the same catchment.

Onsite mitigation methods

  • Sustainable drainage systems (SuDS)
  • Replacing existing in efficient septic tanks and Package Treatment Plants (PTPs) with improved PTPs
  • Provision of new waste water treatment facilities managed by an OFWAT-appointed statutory sewage undertaker

Offsite mitigation methods

  • Creating or restoring semi-natural habitats for example, woodlands, grasslands, or wetlands in the same catchment area
  • Creating a treatment wetland specifically designed to capture run-off from agricultural land or wastewater treatment works
  • Taking land that results in an excess of nutrients to a water system out of use

Natural England’s nutrient mitigation scheme

In March 2023, Natural England launched a credit scheme for developers in the Tees area, allowing them to purchase nutrient credits to offset nutrient pollution and help fund mitigation activities.

Currently, one credit costs £2,300.

In future application rounds and in different catchment areas, the cost of credits may vary, depending on the cost of mitigation projects.

Nutrient mitigation in practice

On-site schemes might include incorporating efficient wastewater treatment facilities or SuDS (which can also be retrofitted into existing developments). Including a water treatment plant into a mitigation proposal proved to be an ideal way to satisfy the “phosphate neutrality” of a two house (total GIA 450 sqm) residential development in Somerset.

Off-site schemes include nature-based projects, such as re-wilding and wetland creation, designed to offset the effects of pollution. The Solent Nutrient Market offers a centralised resource for nutrient trading, where developers can purchase nutrient credits for their protected sites, in turn supporting private mitigation projects in the local area.

Infographic showing The Solent nutrient market
The Solent nutrient market: how it works (Source: Solent Nutrient Market)

In contrast, Herefordshire Council have purchased a land site specifically to pioneer an Integrated Wetlands Scheme, to generate phosphate credits to unlock development in the River Lugg SAC.

Nutrient Neutrality is a controversial issue for developers, as stakeholders look to balance housing provision and environmental targets. With opportunities to meet housing shortfalls, Searchland can help you to establish what catchment areas are affected, and to source suitable sites, both for development and nutrient mitigation.

Thinking about Nutrient Neutrality? Let our team show you how Searchland can help by arranging a 1-2-1 demo today.

October 17, 2023

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