Acid waters in Wales

Research on the process of stream acidification and its impact on Welsh surface waters, carried out over the past decade is presented. Clear evidence of stream acidification was first assembled in Wales in the 1980s. It had mistakenly been assumed that, with its prevailing westerly winds, Wales would receive precipitation substantially unpolluted by the industrial and urban emissions from Britain and mainland Europe. Studies in the vicinity of Llyn Brianne reservoir in central Wales demonstrated a clear correlation between the biological quality and fisheries of streams in the catchment and stream chemistry, particularly pH, aluminum and calcium and catchment land use. Subsequent studies have been conducted on analytical and experimental investigations of inputs, pathways and effects of acid precipitation, taking into account the potentially modifying effects of forms of land use and management. These studies include the manipulation of land-management practices, particularly the application of lime products; a synoptic survey of stream chemistry at over 100 sites throughout Wales, relating water quality to upstream land use and, wherever possible, establishing the biological status of these sites; paleoecological studies to establish the historical changes in lake ecosystems and to explore relationships with land use and atmospheric pollution; and development and applicationmore » of models which facilitate the prediction of changes in the biological and chemical quality of surface waters with changes in emission patterns of atmospheric pollutants and in land use and management practices. Nineteen chapters have been processed separately for inclusion in the appropriate data bases.« less