This book brings together research into the process of stream acidification and its impact on Welsh surface waters, carried out over the past decade or so. It is perhaps surprising that not until the 1980's was clear evidence of stream acidification assembled. In Wales, concerns over pollution had focused water quality sampling principally on the areas of traditional heavy industry and large urban popula tions served by inadequate sewerage systems and sewage disposal arrange ments. Mistakenly, it had 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. Assurance of the high quality of Welsh upland streams, the traditional nursery ground of salmonids, was eroded particularly by studies in the vicinity of Llyn Brianne reservoir in the catchment of the River Tywi of Central Wales. These demonstrated a clear correspondence between the biological quality and fisheries of streams in the catchment and aspects of stream chemistry, par ticularly pH, aluminium and calcium on the one hand, and catchment land use on the other. It is salutary to record that the first signals were of an inexplicable failure of the runs of migratory salmonids into the upper catchment, occupied by the Llyn Brianne reservoir and its influent streams, and the failure to restore the fishery by re-stocking with eggs and fry. Only then did the significance of the recent decline in some other upland lake and reservoir fisheries in Wales become apparent.

Internationally, the wetlands of headwater and upland regions provide many valuable environmental services. This book moves towards a more comprehensive inventory of the benefits and costs of headwater wetlands. It evaluates the research that tries to understand the tolerances, exchanges, checks and balances within headwater landscapes and the downstream impacts of changes in wetlands. It employs case studies and reviews from 21 nations spanning Europe, Africa, Asia and the Americas. It explores the new policy frameworks, changes in land husbandry, new systems for community education, participatory processes and technological interventions required for the effective management of headwater wetlands and the full integration of wetlands (including newly constructed wetlands) into environmental management and planning. In the past, most research dealt with wetlands as isolated features, this book examines wetlands in their watershed management context.

An encyclopedic work! This comprehensive volume is an impressive integration of European and North American research, providing the most complete information to date regarding the problems and solutions associated with aquatic liming. The book gives readers a thorough understanding of the complexities of liming by providing detailed information on design, use, and effects of liming systems for acidic surface waters. It also includes a complete and objective review of liming successes and failures, providing additional information to help readers determine how well a particular method will restore and protect the affected biota. This book is essential for anyone interested in the restoration of acidic lakes and streams.