Where a completed Nutrient Neutrality Budget Calculator identifies that an additional total annual phosphorus load needs to be mitigated (or nitrogen in the case of the Tees Catchment), applicants will need to demonstrate and evidence how this mitigation will be identified and secured.
Mitigation can be provided on site or off site. Offsite mitigation must be located upstream of the development area in the same catchment area.
Mitigation could also be provided in the form of the change in land use of off-site land from a higher to certain lower nutrient generating uses. For example, cereals (arable) or lowland (grazing) to woodland.
In order for us to complete the appropriate assessment applicants seeking to use off site land as mitigation will need to submit:
- Evidence of the mitigation land's current use such as a Baseline Condition Assessment
- Evidence and details of how the proposed habitat will be created, such as a Planting Schedule
- Evidence of how the proposed habitat will be managed and monitored in perpetuity, such as a Habitat Management and Monitoring Plan
- A separate completed Nutrient Neutrality Budget Calculator including the mitigation land
A legal mechanism will also need to be used to secure the land for nutrient neutrality mitigation purposes in perpetuity.
Other nutrient mitigation measures
Other measures which could be taken to reduce nitrogen pollution from development proposals include:
- Lower Water usage - You may wish to consider ways in which your development could reduce the water usage lower than the 120 litres per person per day (which is used in the calculator)
- Lower water usage rates should be evidenced properly and submitted with your completed budget calculator
- Sustainable Drainage Schemes (SuDs) – You may also wish to consider the inclusion of SuDs and design this to maximise the opportunity to capture and remove nitrogen from the surface water runoff of your proposal. The Construction Industry Research and Information Association (CIRIA) has published a guide: Using SuDs to reduce nitrogen in surface water runoff (2023). This is intended for areas where nutrient neutrality is required. The guide outlines the design criteria for a good SuDs scheme that can maximise the opportunity to capture and remove nitrogen
For development within the Teesmouth and Cleveland Coast Special Protection Area you can apply to buy credits that fund mitigation activities, such as creating a new woodland or wetland. This will balance out nutrient pollution produced by your housing development.
Gov.uk website: Tees catchment: how to apply for nutrient mitigation credits from Natural England