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WHY DEVELOPERS ARE STRUGGLING TO KEEP PACE WITH NUTRIENT NEUTRALITY

Nutrient pollution is harming the UK’s water and wildlife, but Natural England’s measures to combat this are causing confusion and housing development delays. Positively, schemes and suggestions for progress are on the horizon

Words by NIAMH SMITH

ousebuilders and developers are coming under increasing pressure to maintain water quality. Nutrient pollution is one of the most harmful environmental issues affecting the UK’s water, according to Natural England and Defra, which have started to implement stringent requirements. Unusually high levels of nitrates and phosphates disrupt natural processes and harm wildlife by causing excess plant and algal growth, which depletes oxygen in waterways and restricts the functioning of aquatic ecosystems.

To combat the issue, Natural England has been advising 74 local planning authorities in several affected areas, including Dorset, Cheshire, Northumberland, and Cornwall, to ensure the development of accommodation—including housing, hotels, student halls, and care homes—achieves nutrient neutrality.

Nutrient neutrality aims to prevent new projects from adding to the nutrient loads caused by the land’s existing use within designated catchment areas. A development is considered neutral if it results in no net increase in harmful nutrients deposited in water systems. If there would be an unavoidable increase in nutrients from a scheme, developers could still achieve net neutrality by purchasing offsets. Natural England introduced its nutrient mitigation scheme in March this year to allow housebuilders to do this. Currently, the Tees catchment—which comprises three rivers: Tees, Skerne and Leven—is hosting the only nutrient mitigation scheme pilot project, which allows developers planning to build within the catchment area to purchase nutrient credits from Natural England. Developers working in the area can purchase one credit to mitigate one kilogram of nitrogen for £1,825. Nutrient credits are used to fund land managers’ mitigation activities, such as creating woodland or wetlands in local areas, to balance out any nutrient pollution the housing development will cause.

Even though the scheme is currently limited to the Tees area, more catchment zones will be added as Natural England continues to work with partners to identify suitable sites for mitigation, focusing on places with the highest housing need. However, many within the construction and planning industry have criticised the schemes for slowing down the development of projects amid a worsening housing crisis.

Housebuilders step back

HNatural England’s nutrient neutrality scheme could reduce between 2,500 and 12,700 new homes being built each year, according to the Home Builders Federation (HBF). The body also estimates the cost of on- and off-site mitigation measures and purchasing nutrient credits to comply with Natural England’s nutrient mitigation scheme will cost developers approximately £5,000 per home in affected regions.

During the planning stage, housing developers operating in catchment areas will have to request a nutrient calculator from their local planning authority or work with consultants to calculate the level of nutrients their project would add to nearby water systems, as well as the cost of mitigating them. Levels of nutrient pollution are measured through an assessment of factors including additional population and water usage.

Due to the cost implications, Lawrence Turner, director at consultancy firm Boyer Planning, says many housebuilders have determined it is more economically efficient to avoid building on areas covered by nutrient neutrality altogether. “At the present time, many developers seek to avoid land that is identified by Natural England as falling into an affected river catchment,” he shares.

Lawrence explains that the problem is particularly acute for developers that acquired land before nutrient neutrality issues arose, because they now face the burden and costs of assessing the nutrient load and delivering mitigation measures.

As more developers avoid building in catchment areas, the shortage of land supply has led to increased competition for sites not affected by nutrient issues and made homes in these regions less affordable. Developers submitting planning applications within areas covered by nutrient neutrality must follow steps to demonstrate that any necessary measures to mitigate nutrient pollution would be followed. Development plans have to include details such as the number of units of overnight accommodation and an assessment of existing land uses on the site, says Simon Packer, director at Turley—a consultancy that has helped secure permission to build 180,000 homes across eight regions in the UK, including in the Southampton area, which is classified as a nutrient neutrality catchment zone.

Assessing existing land use is an important step as it provides a baseline of nutrients already entering the sensitive catchment area, from which further degradation can be assessed. “When you calculate for proposed land use, you usually end up with a net gain in the amount of nutrients you will be adding to the catchment area as part of your development. You then end up with levels of nitrates and phosphates that you would have to mitigate,” notes Simon.

Richard Broadbent, environmental law director at Freeths, stresses the importance of ensuring these calculations are completed during the early stages of planning. He says that once developers have identified the levels of nutrient output associated with their project, they must consider any opportunities that exist on site and in the local area to mitigate them. “If this issue is picked up late in the design and planning process, it can cause a great deal of delay and increased costs. With nutrient neutrality, being forewarned is forearmed,” he emphasises.