Nutrient Management in Planning and Development

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NRW 2024 Compliance Assessment of River SACs

In 2024, Natural Resources Wales (NRW) published its latest compliance assessment of riverine Special Areas of Conservation (SACs) against water quality targets. The assessment draws on water quality data from 2020 to 2023, following methodological standards consistent with the Water Framework Directive.

The assessment found that a majority of SAC river water bodies in Wales are failing to meet NRW’s updated phosphorus targets. These targets are legally binding and are used to assess whether additional nutrient inputs from development can be permitted.

River SACs in Carmarthenshire: Current Status

The following SAC river catchments fall partly or wholly within Carmarthenshire’s boundary:

  • Afon Teifi SAC – Failing
  • Afonydd Cleddau SAC – Failing
  • River Wye SAC – Failing (minor overlap at eastern boundary)
  • River Usk SAC – Failing (limited impact within Carmarthenshire)
  • Afon Tywi SAC – Passing, but with limited headroom

Implications for Planning and Development

Planning advice can be found here. Where river catchments are failing phosphorus targets:

  • New development proposals that increase nutrient loading must demonstrate nutrient neutrality or betterment before permission can be granted
  • Connection to public sewerage infrastructure may be restricted, especially where the receiving wastewater treatment works (WwTW) discharge to failing reaches
  • Mitigation measures must be robust, legally secured, and monitored, and must reduce nutrient contributions to the affected catchment

Where catchments are passing but close to their limit (e.g. Afon Tywi):

  • Proposals will still be subject to Habitat Regulations Assessment (HRA)
  • NRW expects development to demonstrate that it does not compromise the ability to maintain compliance
  • Headroom is closely monitored, and further deterioration may result in additional constraints

Ongoing Review

NRW’s compliance assessments are updated periodically and represent the formal evidence base against which all planning decisions affecting SAC catchments must be made. Carmarthenshire County Council continues to monitor changes and adapt its planning guidance in line with the latest information and data.

For detailed maps and data tables, refer to the NRW 2024 Compliance Assessment Report.