Nitrate pollution concerns halt housebuilding

Five local authorities in the Solent area have put a hold on determining planning applications for new housing as a result of advice from Natural England about nitrate pollution.

Following two rulings by the Court of Justice of the European Union in the ‘Dutch Case’ (C-293/17 and C-294/17) and ‘People Over Wind’ (C-323/17), Natural England has advised local planning authorities in the Solent area that existing uncertainty about the deterioration of the water environment, caused principally by nitrate pollution, must be appropriately addressed in order for the assessment of a planning application to be legally compliant. The advice has led five councils in the Partnership for Urban South Hampshire (PUSH) area to put some planning applications, including for new housing, on hold, for fear of having any decisions to grant planning permission judicially reviewed.

A recent report to Portsmouth City Council’s cabinet summarises the issue, stating that high levels of nitrates from housing and agricultural sources have caused eutrophication (the excessive growth of green algae) in protected waters in the Solent area, which is having a detrimental impact on protected habitats and birds. The report advises that the council is actively exploring a number of both direct and indirect mitigation options that will help to both improve water quality in the Solent and enable development to resume in the city.

The House of Commons Environmental Audit Committee report ‘UK Progress on Reducing Nitrate Pollution’ notes that agriculture is a key source of nitrate pollution, owing to the use of manufactured and organic fertilisers, but it also notes that nitrates and other pollutants can be released from domestic and industrial waste water into water sources. Natural England recommends that the problem is addressed by securing suitable mitigation measures to ensure that planning applications achieve ‘nitrate neutrality’.

Poole Harbour, itself a SSSI, SPA and Ramsar site, also faces issues. The problem has led local planning authorities in Dorset to adopt a Supplementary Planning Document (SPD) detailing how they will ensure that new development is nitrate neutral. The ‘Nitrogen Reduction in Poole Harbour’ SPD details three main mitigation options:

• direct mitigation by improving existing and introducing new nitrate stripping technology at waste water treatment works over and above the statutory minimum;
• direct mitigation by installing technologies to remove nitrates in new developments, such as reed beds and wetlands; and
• indirect mitigation by changing the use of high nitrate input land uses, like agricultural use, to low nitrate input land uses, like woodland and rough grazing land.

It would be possible for PUSH authorities to collect contributions via section 106 planning obligations and the community infrastructure levy, and make agreements with operators of waste water treatment works to mitigate the impacts of nitrates. However, as the SPD notes, nitrate stripping technologies for waste water treatment works are expensive and generate a significant amount of carbon dioxide.

It is difficult to envisage on-site mitigation on smaller, brownfield city centre sites that are not large enough to provide on-site open space incorporating nitrate removal technology. Such sites would be required to provide some form of off-site mitigation. Furthermore, some PUSH authorities, particularly those in built-up areas like Southampton and Portsmouth, do not have high nitrate input agricultural land available to take out of high input use. Smaller developers may also not have the resources to acquire and convert such land.

One potential way to overcome these problems and allow development to come forward would be for the authority in question to acquire high nitrate input land outside of its administrative area and have developers contribute to the cost of its purchase and change of use, either on a case by case basis via a section 106 planning obligation or generally via community infrastructure levy receipts.

In addition to exploring solutions like those detailed above, PUSH is currently lobbying central government and urging it to focus on the sources of the nitrates, by pursuing reforms to the environmental permitting regime (which regulates discharges from waste water treatment works) and waste water treatment practices, rather than putting the regulatory burden on the planning system and development industry.