Principles of nutrient neutrality in relation to development or water discharge permit proposals

What is nutrient neutrality?

Nutrient neutrality is an approach for managing new development and water discharge permit proposals to prevent them from causing any net increase in nutrients for the duration of the authorisation. Nutrient neutrality is applicable in Wales to developments with phosphorus discharges into Special Areas of Conservation (SAC) rivers.

When is it needed?

Applicants for Planning Consents or Environmental Permits for a water discharge will need to demonstrate that their proposals are nutrient neutral where they could increase the amount of phosphorus in a river SAC and water quality targets for phosphorus are already being exceeded, or are failing to meet the targets downstream.

In SAC catchments meeting phosphorus targets, nutrient neutrality may not be required providing that new developments do not cause a   SAC to exceed its water quality targets or prevent them from being achieved in the future.

The nutrient impact of a development will be reviewed in the Appropriate Assessment stage of a Habitats Regulations Assessment (HRA) for a planning or water discharge environmental permit application. Demonstrating nutrient neutrality is a recognised approach to show that a development will not have an adverse impact.

Read more about why we are concerned for our river’s health and which rivers are affected.

How can nutrient neutrality be achieved?

The first consideration in nutrient neutrality should be to minimise or eliminate the amount of nutrient generated by a development. Nutrient balance calculations should then be completed to determine how much nutrient could enter the river environment because of the development or water discharge permit proposal compared with the existing site operation or land use. Some nutrient calculation tools are publicly available for this although their suitability should be checked before use.

To achieve neutrality mitigation will be required to achieve net nutrient impact of a development or water discharge permit. Mitigation measures must avoid impacts on the river environment rather than to compensate for impacts once they have occurred. 

What are the principles of nutrient neutrality?

Development or water discharge permit applications for nutrient neutral developments must demonstrate that all of the following principles have been applied:

  • Calculations must be based on best available scientific evidence and research, including key inputs and assumptions at the time of the Appropriate Assessment.
  • Measures are effective and in place for the lifetime of the development/permitted activity effects, demonstrating how this will be secured, such as legal agreements.
  • Evidence mitigation will be in place when proposed development becomes active. The nutrient neutrality mitigation must be in place and functioning when the proposed development or water discharge permit will start to discharge (directly or via a sewerage system) to the river. If the impact will be phased, it may be that a range of measures may be needed to address impacts over time.
  • Mitigation must not compromise the restoration of the SAC. This means not constraining those measures already in place or which may be required in future to maintain or restore the SAC. Implementation of mitigation measures through nutrient neutrality should not undermine the objectives in the Habitat Regulations aimed at restoring the site to favourable condition. For example, where there are limited options of mitigation available these should be used to maintain or improve the site rather than to enable more discharges to the SAC river.
  • Measures used to demonstrate Nutrient Neutrality must not be double counted. A national register of schemes is likely to be required in order to ensure no double counting occurs.
  • Measures should, where possible be within the development site. Where this is not achieved there must still not be detriment to the SAC. Permissions will not be granted unless the competent authority is satisfied that the SAC will not be impacted. Development or water discharge permit proposals within a SAC river boundary will need to be mitigated at the site or upstream. Development affecting a watercourse that joins a SAC river boundary can have mitigation at the site, up or downstream providing the offsetting occurs before the point at which the development impacts the SAC boundary.
  • Nutrient calculations must be based on precautionary principle. The uncertainty in the nutrient calculations is dealt with by taking a precautionary approach through the use of buffers. This will involve adding a percentage onto the calculation when using a nutrient calculator. This should provide the necessary level of confidence to ensure that new developments or permitting activities will not increase the nutrient load entering SAC rivers.

Where must nutrient neutrality be applied?

Nutrient neutrality for phosphorus is required for new developments and water discharge permits in the catchments and water bodies listed below. Planning authorities have the discretion to require nutrient neutrality for developments in other SAC catchments.

The whole of the River Wye / Afon Gwy SAC catchment, affecting Monmouthshire, Powys, Ceredigion, Carmarthenshire County Councils and Brecon Beacons National Park Authority.

The whole of the River Usk / Afon Wysg SAC catchment, affecting Monmouthshire and Powys County Councils; Blaenau Gwent and Torfaen County Borough Councils and Brecon Beacons National Park Authority.

Part of the Afonydd Cleddau / Cleddau Rivers SAC.  Nutrient neutrality would be required for the Western part of the SAC catchment plus two water bodies on the Eastern Cleddau (GB110061030690 and GB110061030660), affecting Carmarthenshire and Pembrokeshire County Councils and Pembrokeshire Coast National Park Authority.

The whole of the River Teifi / Afon Teifi SAC catchment, affecting Ceredigion, Carmarthenshire, Pembrokeshire and Powys County Councils.

The whole of the River Dee and Bala Lake / Afon Dyfrdwy a Llyn Tegid SAC catchment, with the exception of water body GB111067057080 at the downstream end of the Dee, as phosphate target passes and there are no further river water bodies downstream.  This affects Flintshire, Denbighshire, and Gwynedd County Councils; Wrexham and Conwy County Borough Councils and Snowdonia National Park Authority.

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