DEVELOPMENTS IN WATER-QUALITY STANDARDS AND CLASSIFICATION SCHEMES INENGLAND AND WALES

This paper discusses the changes in national water quality classificat ion schemes in England and Wales that have been proposed following the introduction of new legislation. The conclusion has been reached that two separate systems are necessary. A new General Quality Assessment scheme has been introduced for the purpose of assessing and reporting upon status and trends in water quality. A separate system of Use Clas sifications will be progressively introduced to drive the water qualit y planning process through the setting of Water Quality Objectives on a statutory basis. Recent advances in ecotoxicology have provided the opportunity for the development of new, more ecologically relevant, ap proaches to deriving water quality standards. One example of this is t he development of criteria relevant to rivers affected by intermittent pollution for which alternative ways of expressing standards have bee n proposed and applied in conjunction with dynamic impact modelling te chniques.