Nutrient pollution especially impacts freshwater areas, where nutrient imbalance can harm plants and wildlife. As part of England’s ‘25 Year Environment Plan’, and the Environment Act which aims to end species decline by 2030, planning permission won’t be granted without a developer acting to offset.

Developing wetlands and other innovative schemes to provide nutrient offsets in areas affected by nutrient neutrality, Greenshank Environmental are specialists in this space. To meet requirements, they point developers towards purchasing ‘nutrient credits’, or creating nutrient mitigation schemes themselves.

What is ‘nutrient neutrality’?

Nutrient Neutrality is a new legal requirement within habitat regulations. Developers planning new schemes are obligated to comply. This is because nutrient pollution from new building development can damage the rare ecology of protected aquatic ecosystems. 

Some sites protected by these regulations already have unsustainable levels of nutrient pollution. To slow the impact of this down, all proposals for new development now have to show their new scheme will not make this pollution worse. It has to be a ‘nutrient neutral’ scheme. For new developments, nutrient neutrality is gained by offsetting the nutrients its construction will produce. Typically, developers make this happen through offsetting schemes, like creating new wetlands. 

Nutrient neutrality map

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What causes nutrient pollution?

Nutrient pollution is released into freshwater and coastal areas from a range of different sources, including agriculture, aquaculture, septic tanks, wastewater, urban stormwater runoff, industry and fossil fuel combustion. Deposit from land sources, or the atmosphere.Though efforts to reduce nutrient pollution are already underway, it’s still at unsustainable and damaging levels in many protected ecosystems.    

Which areas are under nutrient pressure?

Twenty seven areas of England, and most of Wales, have been impacted by nutrient pollution. In these areas, more than 72/333 local planning authorities have been affected, and cannot consent to new development, if it’s not nutrient neutral.

Over the next five years, nutrient pollution rates are set to double in scale, covering 65 areas, and more than 140 local planning authorities. Nutrient neutrality is most essential in areas where a large amount of planned development is scheduled. Within the UK, the areas now facing the largest challenges are: 

England 

• The River Tees catchment 
• The River Wensum and Norfolk Broads catchments 
• The Somerset Levels 
• The Solent 
• The Hampshire Avon catchment 
• The River Eden catchment 
• The Derwent and Bassenthwaite Lake catchment 
• The River Wye and Lugg catchment (Herefordshire) 
• The Poole Harbour catchment  
• The River Stour and Stodmarsh catchment   
• The River Wye catchment (Derbyshire) 
• The River Camel catchment  

Wales 

• The River Usk catchment 
• The River Dee catchment 
• The River Wye catchment  
• The River Towy catchment 
• The River Cleddau catchment 
• The River Teifi catchment

How do developers offset nutrients?

Agricultural abandonment schemes

Most of the mitigation schemes providing nutrient offsets are based on abandoning agricultural land. By stopping farming, you remove a source of nutrients by removing fertiliser or animal manure inputs to the land. This is how development has been unlocked in The Solent region. However, this approach is not cost efficient, has big impacts on the livelihoods of farmers, and it’s problematic at a time when food security is more important than ever. 

Agricultural abandonment schemes also don’t work for the nutrient phosphorus, as you need too much land for them to be financially viable. So, this approach can only be taken in areas where nitrogen is the only nutrient of concern.   

Catchment management solutions

There are multiple mitigation options that could be delivered by different types of land management. Including those known as ‘catchment management solutions’, such as…

• Riparian buffers
• Engineered logjams
• Blocking drainage ditches

These solutions have relatively low land take, are supported by evidence and backed by the regulator. Greenshank Environmental’s experts are currently writing guidance for the regulators on how these options could be deployed. 

Catchment management solutions also have a range of extra environmental benefits, including:

• Biodiversity improvements
• Natural flood management
• Carbon sequestration

Wetland schemes

Wetland schemes are another potential mitigation option that can deliver nutrient offsets at scale and without a significant land take, making them both space and cost efficient. This type of solution is also supported by methodology from the regulator.   

Who is involved in deploying a wetland scheme?

• The organisation or people that own the dirty water our wetlands will be treating.
• The relevant local planning authority.
• Natural England: The regulator for the protected ecological sites that the nutrient offsetting is needed for, and who ultimately sign off on wetlands. 
• The Environment Agency, who need to be consulted to obtain discharge permits, for the wetlands to discharge to specific water bodies. They may also need to be engaged for other regulatory assessments.
• Environmental NGOs, or other relevant community groups to manage the wetlands, and meet the ‘in perpetuity’ requirements for long-term maintenance.

What are nutrient credits?

Credits are created on an 'offset per year basis', as they need to offset the same amount of nutrients in perpetuity. 

Greenshank Environmental’s wetland project delivers nutrient offsets that are quantified as kgs of nitrogen, or phosphorus, removed from the environment. Each kg of nitrogen or phosphorus removed is sold as a nutrient credit.  

How are nutrient credits priced?

As credits can only be sold within a very specific catchment area, credit price is driven by local supply and demand. In the open market, in areas with high demand, but limited supply, there will be significant competition — this drives the price up.

Prices can go as high as £100,000/kg, for phosphorus.

Nitrogen credits are typically linked to agricultural offset costs, so tend to come in at a much lower price.  

Reaching nutrient neutrality with Greenshank Environmental 

Developing wetlands and other innovative schemes to provide nutrient offsets in areas affected by nutrient neutrality, Greenshank Environmental are experts in this space. The nutrient offsets their schemes create become nutrient credits that can be used by developers to offset the additional nutrient pollution caused by new developments, within protected areas. 

The team behind some of the UK’s first nutrient mitigation projects

This includes phosphorus treatment wetlands in Herefordshire, decommissioning industrial sites in Hampshire, and taking agricultural land out of production in the Solent. On the evidence and standards needed to secure nutrient credits with certainty, Greenshank Environmental also have a wealth of experience in advising regulators and local planning authorities. They use this expertise to ensure their own mitigation projects will deliver the necessary nutrient credits too, unlocking environmentally harmonious housing development.  

Get in touch with Greenshank to reduce credit costs with local co-investment schemes