Surface Waters (Fishlife) (Classification) (Scotland) Regulations 1997 (No. 2471, S.163).

These Regulations prescribe a system for classifying the quality of inland waters which need protection or improvement in order to support fishlife. The classifications SW ("salmonid waters") and CW ("cyprinid waters") reflect the mandatory values assigned by Directive 78/659/EC on the quality of fresh waters needing protection or improvement in order to support fishlife (reg. 2). Regulation 3 sets out the standards for compliance. The Scottish Environment Protection Agency shall ensure that waters classified under these Regulations are sampled and samples are analysed in accordance with the following provisions of this regulation. Regulation 4 prescribes the methods and frequency of sampling. Regulation 5 specifies derogations: the Agency may derogate from the requirements of these Regulations: (a) in the case of requirements marked (0) in the Schedule to these Regulations, because of exceptional weather or special geographical conditions; or (b) where waters classified under these Regulations undergo natural enrichment in certain substances as a result of which they do not comply with the requirements specified in the Schedule to these Regulations for waters of the relevant class.