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 nutrient discharges into affected designated sites.
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 where water quality targets are already being exceeded, or are failing to meet the targets downstream
- the amount of nitrogen in a specified water body of a marine SAC, or it’s upstream freshwater catchment, and has one or more features in unfavourable condition for dissolved inorganic nitrogen (DIN) and an associated ecological response.
The nutrient impact of a development will be reviewed in the Appropriate Assessment stage of an 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.
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 water environment because of the development or water discharge permit proposal compared with the existing site operation or land use. Welsh Government have developed a Nutrient budget calculator which can be used for this step of the process.
To achieve neutrality mitigation will be required to achieve no net nutrient impact of a development or water discharge permit. Mitigation measures must avoid impacts on the environment rather than to compensate for impacts once they have occurred. The Mitigation Measures Menu developed for both phosphorus and nitrogen provides a list of example mitigation measures.
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 water environment. If the impact will be phased, it may be that a range of measures may be needed to address impacts over time.
- 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 or its catchment.
- Measures used to demonstrate Nutrient Neutrality must not be double counted.
- Consideration will need to be given as to the location of any mitigation relative to where the development will have its impact on the SAC. Measures should, where possible be within the development site. Where this is not achieved there must still not be detriment to the SAC.
- For SAC Rivers, 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, upstream or downstream providing the offsetting occurs before the point at which the development impacts the SAC boundary.
- For Marine SACs, for discharges directly into the SAC, the mitigation measure will need to be upstream of the location where the development site run off and wastewater input will have a direct impact on the SAC. If the discharge is indirect (i.e. upstream in the catchment of Marine SAC), then the mitigation measures can be upstream or downstream within the catchment, as long as it will provide the offsetting before the point at which the development impacts the Marine SAC.
- 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 the SAC.
Where must nutrient neutrality be applied?
Nutrient neutrality 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.
Neutrality for phosphorus
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.
The whole of the River Teifi / Afon Teifi SAC catchment, affecting Ceredigion, Carmarthenshire, Pembrokeshire and Powys County Councils.
The whole of the Afon Gwyrfai and Llyn Cwellyn SAC catchment, affecting Gwynedd County Council and Eryri National Park.
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. This affects Flintshire, Denbighshire, and Gwynedd County Councils; Wrexham and Conwy County Borough Councils and Snowdonia 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 lowest main River Wye waterbody failing is GB109055042250 Wye - conf Afon Elan to conf R Ithon. Nutrient Neutrality will be required within this water body and throughout the catchment above this point. Additionally, there are other water bodies within the SAC that fail below that point, listed below. Nutrient Neutrality will also be required within each of those water bodies and throughout any parts of the catchment above.
The furthest downstream are:
- GB109055036680 Cledan - source to conf R Irfon;
- GB109055036990 Scithwen Bk - source to conf R Wye;
- GB109055037160 Builth Dulas Bk - source to conf R Wye;
- GB109055041870 Afon Gwesyn - source to conf R Irfon;
- GB109055041900 Howey Bk - source to conf R Ithon;
- GB109055041960 Mithil Bk - source to conf R Ithon;
- GB109055042070 Clywedog Bk - conf Bachell Bk to conf R Ithon;
- GB109055042140 Ithon - conf Gwenlas Bk to conf Camddwr Bk;
- GB109055036950 Afon Llynfi - conf Dulas Bk to conf R Wye;
- GB109055037030 Clettwr Bk - source to conf R Wye;
- GB109055037060 Bach Howey Bk - source to conf R Wye;
- GB109055037080 Edw - conf Clas Bk to conf R Wye;
- GB109055042080 Nantmel Dulas - source to conf R Ithon;
- GB109055042110 Aran - source to conf R Ithon;
- GB109055042130 Camddwr Bk - source to conf R Ithon;
- GB109055042190 Afon Chwefru - source to conf R Irfon.
This affects Powys, Ceredigion, Carmarthenshire County Councils and Bannau Brycheiniog National Park Authority.
Neutrality for nitrogen
Part of the Pembrokeshire Marine SAC. Nutrient Neutrality would be required for the Milford Haven Inner transitional waterbody and the whole of its upstream, freshwater catchment. This affects the Pembrokeshire Coast National Park Authority and Pembrokeshire County Council.
Part of the Carmarthen Bay and Estuaries SAC. Nutrient Neutrality would be required for the Burry Inlet Inner transitional waterbody and the whole of its upstream, freshwater catchment. This affects Swansea Council, Carmarthenshire County Council and a smaller area of Neath Port Talbot Council.
Part of the Cemlyn Bay SAC. Nutrient Neutrality would be required for the Cemlyn Lagoon waterbody and its catchment. This affects Ynys Môn County Council.
These areas are available to view and download as a GIS file from DataMapWales.