Nutrient Neutrality

Effects of Eutrophication on Development Sites

Water bodies can experience a build-up of nutrients known as eutrophication, leading to an accumulation of phosphorus and nitrogen pollution that has the ability to cause countless issues. For example, nutrient pollution can increase the risk of flooding, cause harm to ecosystems in or near water, and worsen water quality through algal blooms and oxygen depletion.

Drivers of eutrophication include the use of fertilisers in agricultural activity, changes in land use such as gardens causing nutrient runoff into nearby watercourses, and an increase in the number of residents, leading to heightened volumes of sewage. All in all, the possibility of excess nutrients can impact a proposed development, particularly in the case of statutory designated sites.

Specifically in planning, problems caused by eutrophication have the potential to be hazardous to the environment and costly to the developer. Changes to freshwater habitats and a decrease in oxygen can pose serious problems to biodiversity, as it will worsen the ecological health of the water and the quality of living for species of flora and fauna within it.

In terms of the side effects on developments, lake, stream or river pollution could dispute efforts to support sustainable development and remain compliant with biodiversity net gain (BNG), likely affecting planning applications. Counteracting the environmental impact of eutrophication is possible, however, through nutrient neutrality.

What is Nutrient Neutrality?

Nutrient neutrality is a type of environmental concept that applies to new developments throughout the country. It works to prevent additional nutrient pollution from occurring in local watercourses such as lakes, estuaries, rivers and coastal waters. Suitable mitigation measures and efforts to offset potential increases in nutrient pollution will then reduce the concerns otherwise raised by the presence of nitrogen and phosphorus.

Reducing the likelihood of eutrophication impacts is especially important in protected sites such as special protection areas (SPAs), RAMSAR sites, special areas of conservation (SACs) and sites of special scientific interest (SSSIs). The aim is to make the development site nutrient-neutral, meaning that the created nutrient load is offset or mitigated to such a point that the net effect on current nutrient levels is at zero.

Due to the nature of catchment areas, water courses collect rainwater, run-off and animal waste from agricultural land and partially treated sewage, bringing with it a nutrients issue, as high levels of nitrogen and phosphorus cause eutrophication. Additional wastewater entering rivers and wetlands as a result of new homes, tourist attractions, wastewater management or diverted river water is only likely to see increased levels of total phosphate and nitrogen.

Nutrient Neutrality in the Law

The government recognises the severity of additional pollution corrupting bodies of water, with Natural England’s nutrient mitigation advice in June 2019 affecting 74 local planning authorities and insisting on neutrality before planning permission is considered. The Department for Levelling Up, Housing and Communities (DLUHC) amended the regeneration bill, and once it achieved royal assent, it became the Levelling Up and Regeneration Act 2023 (LURA), replacing the Water Industry Act 1991 and enforcing nutrient pollution standards onto wastewater treatment works.

The DLUHC attempted to remove nutrient neutrality requirements but was rejected by the House of Lords in September 2023, as it would contradict environmental regulations and cause damage to nature. Instead, other steps were taken, such as the local government supporting arable farming to reduce and prevent additional nutrients from spreading. Nutrient neutrality legislation also features within various directives, laws and habitat regulations, such as the Conservation of Habitats and Species Regulations 2017 and the Town and Country Planning Act 1990.

Buying Nutrient Neutrality Credits

A development proposal will ideally be designed in such a way that nutrient neutrality will be deliverable on the site through, for example, upgrading existing private sewage treatment plants or setting a provision of sustainable drainage features and wetlands.

Sharing similarities to the last resort option of buying biodiversity units or credits as a way of accomplishing BNG when undeliverable on-site, developers are able to purchase nutrient neutrality credits as a means of nutrient offsetting in a new development.

In the space below, we’ve set out the nutrient neutrality methodology for buying credits:

Steps for Purchasing Nutrient Neutrality Credits

1. Evaluate Eligibility and Requirements

After confirming that the development site does in fact need nutrient neutrality by speaking to the local authority or Natural England, the developer would need to quantify the predicted nitrogen and phosphorus exposure from the development and on the environment. Without consideration of eutrophication, planning permissions simply will not be given.

A calculation will usually be created following a broad ecological assessment such as an environmental impact assessment (EIA) or preliminary ecological assessment (PEA) for large developments – effectively acting as a nutrient neutrality assessment – or simply as a result of an expected occupant increase in small developments. Arbtech can undertake nutrient neutrality assessments, EIAs and other ecology surveys, as well as any that overlap, such as a habitats regulations assessment (HRA) or a BNG assessment to generate biodiversity net gain units.

2. Consider Schemes and Providers

Various nutrient neutrality credit schemes and projects are available for developers to refer to for nutrient neutrality. Like buying statutory credits for BNG, nutrient mitigation credits can be bought for off-site improvements to other areas affected by eutrophication whenever direct site restoration or enhancement isn’t viable. It can also pay for the septic tanks of local homeowners or contribute to nearby waste treatment facilities.

A large number of nutrient mitigation schemes and nutrient mitigation projects are provided by conservation organisations, local authorities and third-party companies, and a nutrient offset market helps developers track down a site-specific quantity of credits to buy and sell. Instead of joining an open market, however, you can buy nutrient credits from Arbtech, giving us the responsibility of meeting the requirements on your behalf locally or even in the same catchment area.

3. Review Terms of Credit Purchase

Mitigation providers are typically given approval by certified regulators, preventing developers from inadvertently choosing to buy credits from untrustworthy or unlicensed sellers. Not only that, but it’s equally important to ensure that the correct number of credits are purchased, as failing to meet the mitigation requirements will only trigger further delays and additional fees, or leave you paying more than you should be.

Unlike other sources, our team can remain involved with a development project from determining the level of mitigation required to the point of conducting the appropriate assessment and seeking credits available long-term to satisfy the nutrient mitigation scheme. If, alternatively, you opt for another provider, make sure there are guarantees that avoid short-term, unreliable or insufficient mitigation solutions.

4. Incorporate Credit Purchase into Planning Application

Within the planning system, developers need to provide documentation of the credit purchase to the local planning authorities, presented as a part of the nutrient neutrality plan that will be displayed within the report for the assessment. The mitigation burden will then be lifted, as the report acts as evidence that the developer has been compliant with the nutrient neutrality regulations.

At this point, it would also be vital to guarantee that the credits are registered with a registry or tracking system. When it comes to submitting an application for full planning permission, the credit purchase should be included in the report from the ecology survey that was conducted to meet the legal agreement, and a provisional nutrient credit certificate can be used as proof that a deposit was paid.

5. Continue to Monitor Credit Progress

Once the local planning authority is sufficiently happy that a developer has been able to achieve nutrient neutrality, planning consent can be granted and a final nutrient credit certificate will be released as proof of the credit purchase.

Many new housing developments can take a long period of time to complete, and as a result of that, developers may need to renew or extend credits. Even if the purchased credits suffice, it would be advisable to keep tabs on any future updates on how the credits are used.

Nutrient Neutrality Calculation

A Natural England nutrient neutrality calculator summarises the factors that need to be considered before a developer can fully quantify the required number of nutrient credits. Several worksheets are available on the gov.uk website, and between them, they make it possible to gauge the nutrient budget for developers affected by eutrophication.

Below, you will find a brief explanation of each worksheet’s purpose:

Worksheet 1

Inputs:

• Daily Water Usage
• Date of First Occupancy
• Number of Residential Units
• Occupancy Rate
• Wastewater Treatment Works Name

Outputs:

Nutrients from Waste Water

Worksheet 2

Inputs:

• Catchment
• Nitrate Vulnerable Zone (NVZ)
• Pre-Development Landcover Area
• Pre-Development Landcover Type
• Rainfall
• Soil Type

Outputs:

Nutrients from Current Land Use

Worksheet 3

Inputs:

• After Development Land Cover Area
• After Development Land Cover Type

Outputs:

Nutrients from Future Land Use

Worksheet 4

Inputs:

• Landcovers in SuDS Catchment
• Per Cent of Flow Entering SuDS
• Removal Rates
• SuDS Catchment Area
• SuDS Features

Outputs:

Nutrients Removed Through SuDS

Worksheet 5

The net increase in nutrients as a result of the development is determined based on all worksheets combined. With the addition of an extra buffer, the nutrient budget for credits needed can then be confirmed.

Natural England and Nutrient Neutrality Maps

Natural England also provides nutrient neutrality catchment maps to assist developers, planners and local authorities with acknowledging areas affected by nutrient neutrality. Maps for nutrient neutrality display the affected catchments around particularly sensitive water bodies that are notably vulnerable to eutrophication.

Managed by the Environment Agency (EA) and organised within the River Basin Districts (RBD), the main nutrient neutrality catchments across England include:

You can view the nutrient neutrality catchment maps from Natural England online.

Cost of Nutrient Credits

Nitrogen credits and phosphate credits are priced up in a way that varies throughout the country, with factors such as the demand, location, market conditions and type of mitigation all playing a role in the cost to generate a positive neutral impact.

The cost is based on a payment per kilogram of total nitrogen and total phosphorus offset per year. It would broadly range from between £1,500 to £5,000 per kilogram per year. Other factors, however, will influence the cost, such as:

• Administration and Monitoring Fees
• Changes to Policy
• One-Time Fees v Long-Term Payments
• Public v Private Providers
• Supply Constraints
• Type of Mitigation Sites and Projects

Get Help with Nutrient Neutrality in Planning

We’ve explained the key facts around nutrient neutrality, assessments and buying credits, but before you decide to choose us as your provider of eutrophication services, read more about how we specifically operate on affected sites, what makes our team capable of assisting you, how you can contact our team for help, and the moves we make to abide by the nutrient neutrality rules.

Nutrient Neutrality Advice

Whether new projects are in protected areas, certain areas close to listed catchment areas, the development falls under the category of housing projects or other schemes that are recognised as threats to water quality, or local authorities or applicable regulators such as Natural England advised you to uphold a new duty to combat eutrophication, our team can provide advice on nutrient neutrality.

Our team has worked with housing developers, planners, local planning authorities and a wide array of other professionals in planning. If it is possible to initiate an interim solution such as installing buffer strips or cover crop, we will prioritise this option, but if the circumstances of the present habitats’ sites and your aims in securing a housing delivery call for new credits to be bought elsewhere, we can also help with this process.

The nutrient neutrality consultants we manage operate under the best practice guidelines and ensure that all issued advice contributes to the developer’s goals of seeing the planning project completed successfully. We are used to dealing with developments on a protected site or in other locations that could otherwise be tricky to deal with, but through the nutrient neutrality guidance we provide, you should see no problem in obtaining planning consent.

Nutrient Neutrality Mitigation

Using the primary nutrient neutrality principles as a foundation for every step we take, our assessments incorporate such other considerations as environmental schemes, feasibility studies, local plans, the national planning policy framework (NPPF), the nature recovery network, planning practice guidance and input from competent authorities and the planning advisory service.

For the mitigation burdens to be addressed accordingly, our team of dedicated nutrients advisors will submit a nutrient neutrality assessment and mitigation strategy that directly corresponds with the affected catchment of the new residential development, housing development or other potential sites that are expected to harm the quality of water bodies.

An advanced set of skills designed to contribute proactive interventions and mitigation options to see planning applications received and accepted enable developers to benefit from numerous qualities across our team. For instance, we can help with eutrophication in relation to carbon sequestration, new semi-natural habitats of certain plants and any adverse effect on dirty water catchments, all to support the planning process.

Purchase Nutrient Neutrality Credits from Arbtech

A permanent residential development or project involving tourist attractions, wastewater or changes to land use has the potential to create new wetlands or turn the local water quality from a favourable condition to an unfavourable condition. Our aim is to achieve nutrient neutrality on the same land, but if it isn’t possible to push nitrogen and phosphorus to lower levels, we can work on a nutrient mitigation scheme to purchase the changes via credit accounts.

If your development is set for the coming months, show consideration to the potential damage caused on your specific project site by leaving the assessment and credit trading responsibilities to Arbtech. Speak to our team today by completing a quote form, emailing us, calling us or messaging us on our socials. We can then assess your needs, help you through the planning application process, uncover further information about your site and secure planning approval.

Alternatively, if you need help with buying nutrient credits, email us at [email protected].