Water Quality Issues in the Solent Catchment Area

An update on Nitrate & Phosphate credits

The context

The Solent has recognised problems from nitrate enrichment; high levels of nitrogen from human activity and agricultural sources in the catchment have caused excessive growth of green algae (a process called eutrophication) which is having a detrimental impact upon protected habitats and bird species. Since mid-April 2019 Natural England (NE) has required developers in south Hampshire including the Borough of Eastleigh to quantify the nitrate level of their development and mitigate any increase in nitrates compared to the existing land use. A development must demonstrate how it will ensure for at least 80 years there will be no nitrate loading from the development within the Solent.

Ultimately this issue needs to be dealt with at a Government level and the Council will continue to lobby government and work with other Councils, Partnership for South Hampshire (PfSH) and other outside bodies to find a long term solution to this issue. Whilst this is progressing, at a strategic level, PfSH continues to develop a coordinated strategy to mitigate the impact of additional residents in new housing.

What we're doing 

Council planners have agreed with Natural England a short-term interim strategy to enable planning decisions to continue to be issued (whilst meeting our obligations under the Habitat's Regulations) while a more comprehensive and strategic solution is determined. With mitigation measures in place, the Council will be able to continue to grant planning permissions to ensure we continue to deliver much-needed new homes. 

For all current and new planning applications, planning staff have asked developers to undertake a nutrient budgeting assessment using Natural England’s methodology. A nitrate neutral development can be achieved in a number of ways, one of which is working with the Council to seek to remove land that the Council owns from an agricultural use to offset any increase in nitrates as a result of the development.

The Council has successfully acquired 194 acres of land with the primary purpose of offsetting the nitrate impact of development. As information develops on the impact of nitrates and mitigation methodologies it is appropriate to review charges.

Updates on Nitrate and Phosphate 'credits'

In March 2020 Cabinet agreed an initial charging policy for nitrate credits offered by the Borough to developers as a mechanism to mitigate any increase in nitrates arising from development. 

In March 2021 Cabinet agreed to charge per nitrate credit rather than a charge per dwelling.

In March 2022 Natural England’s updated guidance advised that mitigation is now also required to address the impact of phosphates in the River Itchen catchment area.

In July 2022 Cabinet agreed an interim Phosphate Mitigation Strategy including on-site mitigation and the sale of phosphate credits.

A limited number of credits are available for purchase within the Itchen catchment, at a cost of £50,000 per credit.

Note: One credit is equivalent to one kilogram of total nitrate or phosphate per year (KgTN/yr or KgTP/yr).

Read the Cabinet report on nitrates

Read the Cabinet report on phosphates

Information on the Eastleigh Borough Council's Nutrient Offset Schemes

Natural England Budget Calculators and guidance

Further information on nutrients