These data identify the compliance of Welsh river Special Areas of Conservation (SACs) regarding targets for seven water quality attributes: Dissolved Oxygen, Biochemical Oxygen Demand, Total Ammonia, Unionised Ammonia, Trophic Diatom Index, pH and Acid Neutralising Capacity. The targets and methods of assessment are set at a UK level by the Joint Nature Conservation Committee as published in the Common Standards Guidance for Rivers 2016, and form part of the conservation objectives for the riverine SAC features. There are nine SACs in Wales with riverine features (known in their respective Core Management Plans as):
• River Dee and Bala Lake
• Afon Gwyrfai a Llyn Cwellyn
• Coedydd Derw a Safleoedd Ystlumod Meirion (Afon Glaslyn)
• Afon Eden - Cors Goch Trawsfynydd • Afon Teifi
• Afonydd Cleddau
• Afon Tywi
• River Usk
• River Wye
For the purposes of water quality reporting, Natural Resources Wales (NRW) divides rivers into units called water bodies. A total of 119 (of a possible 127) water bodies, each with a single sampling point, were assessed for one or more attribute.
Water quality data collected by NRW’s routine surveillance monitoring programme for a three-year period (1st of January 2017 – 31st December 2019) were extracted from the NRW water quality database (KiWQM) to assess compliance with targets.
Data were not available for all attributes for all water bodies due to the risk-based design of NRW’s monitoring programmes. The majority of water bodies were assessed for more than one attribute. All data were subject to robust quality assurance processes. The data consists of two products: 1. An Excel spreadsheet summarising results and 2. GIS layers consisting of the WFD catchment area water bodies, clipped to the Welsh border and excluding water bodies not overlapping with river SAC boundaries.
