Following rulings by the Court of Justice of the European Union, Natural England has given advice to halt the planning applications of up to 10,000 houses as a result of the uncertainty surrounding the water quality of the Solent area due to nitrate pollution. Humans create around 450 million tons of nitrogen annually, and in high concentrations within the environment, it can be damaging. The main culprits of high levels of nitrogen in Solent are nitrogen-containing fertilisers in agriculture, and the wastewater and sewage from existing communities and proposed developments.

The primary concern in the Solent area is the quality of the water, with high levels of nitrogen causing eutrophication (excessive growth of green algae) which can result in oxygen depletion within rivers and groundwater, and therefore a loss in species richness of protected habitats and bird species. An increase in nitrates also leads to an increase in nitrogen oxides, which can impact air quality and raise acidity levels in water. High levels of nitrogen in the atmosphere can also contribute to the greenhouse effect and acid rain, which are both concerns relating to climate change.

The Solent is located with a Special Protection Area (SPA), which is protected under the Conservation of Habitats and Species Regulations 2017. In order for councils to conform to the requirements of the Water Framework Directive and the Habitats and Species Regulations 2017, new developments need to have avoided harm to the protected site or ensure that appropriate mitigation measures are put in place to avoid harm. Under this legislation, consents for planning applications may not be issued unless there are appropriate mitigation measures in place to ensure that developments are made ‘nitrate neutral’. Building new houses without appropriate mitigation measures will increase levels of nitrogen, adding to nitrogen loading within the habitat due to additional sewage output. However, the need for new housing and the increasing population means that the avoidance of nitrogen generation is not possible.

The suspended granting of planning permissions has led to developers being concerned that they will lose money, or in a worst-case scenario, go out of business. Keith Oliver from Town Planning Experts in Portsmouth said, “The government is saying it needs more houses but they have made it impossible to meet”. The new advice is likely to delay any new planning applications and it has been questioned whether the economic needs of the local communities are likely to be met considering the environmental targets set out in Portsmouth’s climate change aims. Officers are planning to meet with Southern Water to discuss ways in which the current treatment of water can be adapted to improve water quality.

The current options to mitigate nitrogen inputs from new developments are either ‘direct’ through improving nitrogen stripping at Sewage Treatment Works or using alternative sewage treatment techniques such as wetlands or reedbeds, or ‘indirect’, such as through offsetting nitrogen generation. Despite the concerns raised by planners and developers in the area regarding the complexity and issues that this strategy may cause, similar mitigation strategies have been put in place in other areas where nitrogen loading is an issue, including Poole Harbour. One potential option to offset nitrogen in Poole Harbour that is being considered by the Environment Agency and Natural England is the feasibility of ‘nitrogen trading’ Payments for Ecosystem Services (PES) scheme. The concept of PES schemes allow ecosystem services to be traded between buyers and sellers. The PES scheme would allow those seeking planning permission for new developments to pay for a reduction in nitrogen discharges to mitigate nitrogen loading.

The issue is likely to impact all planning applications for residential development in the Partnership for Urban South Hampshire (PUSH) area, including Fareham, Gosport, Havant, East Hampshire and Portsmouth. Currently, Natural England will require all large residential developments to achieve nitrate neutrality and have produced a ‘working draft’ methodology for developers to calculate the nitrogen budget of their development and determine whether the nitrogen load is expected to increase. The study by the Environment Agency and Natural England states that within the Pool Harbour catchment, nitrogen mitigation requirements for new developments are likely to be between 21 and 40 tonnes of nitrogen per annum.

Developers have been advised to engage with the Local Planning Authority and statutory consultees at the beginning of the planning process in order to ensure a suitable and effective mitigation approach is in place. It has also been advised that those who are currently managing agricultural land are to re-consider current agricultural practices to improve net nitrogen loading. The issue of nitrate neutrality is likely to challenge the entire housebuilding industry, and while the scheme is in place to protect the environment, it has also highlighted how planning authorities are adapting their strategies as a result of human impact and climate change.

If you are concerned for any issues regarding your development in this area and whether this may impact your development, please feel free to contact us and we would be happy to offer advice.

Lizzie Murray-Clark
Environmental Consultant

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