The U.S. Clean Water Act calls for the minimization of "adverse environmental impact" at cooling water intake structures. To facilitate an exchange of information among all stakeholders in the issue, the Electric Power Research Institute organised a national symposium in 2001 to discuss the meaning of adverse environmental impact and methods for its assessment. Technical experts in federal and state resource agencies, academia, industry and non-governmental organizations attended the symposium. This is a collection of peer-reviewed papers, intended both to inform and to encourage the development of rules regarding the minimization of adverse environmental impact at cooling water intake structures.

Towards the Balance and Management of the Carbon Budget of the Biosphere The current state of misunderstanding of the global C cycle and our failure to resolve an issue that has been debated for 100 years (Jones and Henderson-Sellers, 1990) speaks loudly about the limitations of modem science when faced with the complexity of the biosphere. Efforts to understand and balance the global C budget have gone through several phases. First was a holistic view of the C budget as part of efforts to understand the geochemistry of the Earth (e. g. , Clarke, 1908). Next, came a period of data collection and sythesis which focused on the diversity of sectors of the biosphere. This phase culminated in the early 1970's with the realization that humans were greatly impacting the global C cycle as measured at the Mauna Loa Observatory (Keeling et al. , 1973). New syntheses of the global C budget emerged at this time (Woodwell and Pacan, 1973; Bolin et al. , 1979). The next phase was one of controversy and intense focus on particular sectors of the biosphere. The controversy rested on discrepancies about the role of the terrestrial biota in the global C cycle and the failure to account for sufficient C sinks to absorb all the C emitted by land-use change in the tropics (Woodwell et al. , 1978, 1983; Houghton et al. , 1983).

The acidification problem is still an area of great concern. Many areas in the world are subject to large, in some cases increased, deposition ofacidifying substances. Scientific research has played a crucial role in the discovery and exploration of the problems as well as a basis for the development ofcontrol strategies for the more than 25 years that have passed since Svante Oden first presented his results. Even today scientific research is important as a tool for policy, most clearly observed in the effect-oriented second sulphur protocol under the Convention on Long-range Transboundary Air Pollution signed in Oslo 1994. Without a close international scientific cooperation this protocol would have never been able to develop. The 5th Conference on Acidic Deposition Acid Reign '95? should be seen in the context ofthe ongoing process to strengthen the scientific background for policy. It was therefore a great pleasure for Sweden to host the conference. It became a success in many respects. First the number ofscientists and presentations made this conference the most comprehensive ever on acidic deposition. From the organizers, we were extremely pleased to see the number of participants and contributions from countries outside Western Europe and North America. These participants turned the focus to areas showing signs ofan increased acidification problem and areas still under heavy pressure from acidic deposition. An excursion to the Czech republic prior to the conference underpinned this interest.

Acknowledgements Conference Summary R. D. EVANS, A. PROVINI, J. S. MATIICE, B. T. HART and J. WISNIEWSKI/Interactions Between Sediments and Water: Summary of the 7th International Symposium 1-7 Sediment I Water Dynamics D. E. WALLING and W. HE /Investigating Spatial Patterns of Overbank Sedimentation on River Floodplains 9-20 R. JEPSEN, J. ROBERTS and W. LICK / Effects of Bulk Density on Sediment Erosion Rates 21-31 T. G. MILLIGAN and D. H. LORING / The Effect of Flocculation on the Size Distributions of Bottom Sediment in Coastal Inlets: Implications for Contaminant Transport 33-42 loG. DROPPO, G. G. LEPPARD, D. T. FLANNIGAN and S. N. LlSS / The Freshwater Floc: A Functional Relationship of Water and Organic and Inorganic Floc Constituents Affecting Suspended Sediment Properties 43-53 C. H. TSAI and J. Q. HU / Flocculation of Particles by Fluid Shear in Buffered Suspensions 55-62 P. M. STONE and D. E. WALLING / Particle Size Selectivity Considerations in Suspended Sediment Budget Investigations 63-70 Q. HE and D. E. WALLING / Spatial Variability of the Particle Size Composition of Overbank Floodplain Deposits 71-80 C. YEN and Y. LIN KEY / Variations of Bed Surface Sediment Size in a Channel Bend 81-88 M. STONE and B. G. KRISHNAPPAN / Transport Characteristics of Tile-Drain Sediments From an Agricultural Watershed 89-103 U. KERN and B. WESTRICH / Sediment Budget Analysis for River Reservoirs 105-112 A. I. PACKMAN, N. H. BROOKS and J. J.

Most of the attention with respect to the increase in atmospheric greenhouse gas concentrations centers around three issues: human-generated sources of carbon, mostly from burning fossil fuels; tropical deforestation, which accelerates the production of atmospheric carbon while causting havoc with biodiversity and the economic development of tropical countries; and the temperature increase that may accompany increased atmospheric greenhouse gas concentrations. This is the first book to focus extensively on the reverse to emissions of carbon dioxide (CO2), i.e. the sequestering of atmospheric carbon by aquatic and terrestrial ecosystems. Natural ecosystems are currently sequestering carbon and it is economically feasible to manage existing and additional terrestrial (forest, soil, saline land) and aquatic (coastal, wetland and ocean) ecosystems to substantially increase the level of carbon storage. The prospect of managing natural systems to absorb additional carbon should begin to change the mindset under which scientists, policy makers and society deal with the issue of further greenhouse gas increases.

The early 1990's marked an environmental watershed for our countly. Under two federal administrations significant environmental legislative, regulatOly and institutional changes took place which affected our Nation's wetland resources. Injust a few years, we have seen rapid evolution in the way in which we view wetlands with more emphasis on specific wetland types and the geographic provinces in which they occur. This Southern Appalachian Man and the Biosphere (SAMAB) conference on "Wetland Ecology, Management and Conservation" represents just one example of our desire to understand wetlands in non-coastal regions of the southern United States. The backdrop to this conference was one where the government, universities, and private sector have come together to create a broader and more sophisticated understanding of environmental stewardship for our water resources, especially wetlands. Although enforcement of environmental legislation by federal and state government agencies - limited by manpower shortages, budgetary constraints and undermined by weak enforcement - remains strong as measured by world standards; the realization that environmental degradation of wetlands is likely to get much worse necessitates a greater commitment and increased resource allocation for wetland protection and management. These contiIUled pressures on the wetland resource will create substantial opportunities for the application of environmentally-sound technologies and interdisciplinmy modeling teams to keep abreast of the factors influencing wetland integrity and function in the last half of the 1990's.

The proceedings of a special technical session dealing with the addition of Ca based materials to waters and soils for the purpose of restoring or enhancing fisheries in acidified waters are contained in this volume. The session was part of the North American Fisheries Society's annual meeting sponsored by the Water Quality Section of the Society. While the concept of liming is not new, the extent of the recent research, demonstrations and applications reported at the conference is enlightening. Six countries are represented by government, state and private sector participants. The scope of activities reported in the following 23 papers range from the simple to the very complex addition of liming materials to ponds, lakes, streams and watersheds. This volume of presentations is broad and impressive as are the methods used in the actual application of the neutralizing materials. Those programs that are demonstration application oriented are deploying techniques that are either new or modifications of existing technology.

ACKNOWLEDGEMENTS IX PART I CONFERENCE SUMMARY STATEMENT R. W. BROCKSEN, W. CHOW, E. D. DAUGHERTY, Y. G. MUSSALLI, J. WISNIEWSKI and A. L. WOODIS I Clean Water: Factors that Influence its Availability, Quality and its Use: Summary of the International Water Conference 3-7 PART II WATER RESOURCE OVERVIEWS S. PECK I Managing and Protecting Our Water Resources 11-20 R. BROCKSEN, W. CHOW and K. CONNOR I Addressing Electric Utility Surface Water Challenges 21-29 C. LOHSE-HANSON I Lake Superior Binational Program: The Role of Electric Utilities 31-40 J. A. VEIL and D. O. MOSES I Consequences of Proposed Changes to Clean Water Act Thermal Discharges 41-52 PART III ECOLOGICAL I HEALTH RISKS c. SEIGNEUR, E. CONSTANTINOU and L. LEVIN I Multipathway Health Risk Assessment of Power Plant Water Discharges 55-64 C. W. CHEN, J. HERR, R. A. GOLDSTEIN, F. J. SAGONA, K. E. RYLANT and G. E. HAUSER I Watershed Risk Analysis Model for TVA's Holston River Basin 65-70 S. FERSON, L. R. GINZBURG and R. A. GOLDSTEIN I Inferring Ecological Risk from Toxicity Bioassays 71-82 C. ARQUIETT, M. GERKE and I. DATSKOU I Evaluation of Contaminated Groundwater Cleanup Objectives 83-92 G. L. BOWIE, J. G. SANDERS, G. F. RIEDEL, C. C. GILMOUR, D. L. BREITBURG, G. A. CUTIER and D. B. PORCELLA / Assessing Selenium Cycling and Accumulation in Aquatic Ecosystems 93-104 D. W. RODGERS, J. SCHRODER and L.

This special volume contains papers that are partly based on contributions to the symposium "Minesite Recultivation" wh ich was held at the Brandenburg Technical University in Cottbus, FRG in lune 1994. Ouring this symposium, various aspects of research into the recultivation of open-cast minesites were discussed. As a prime example, the symposium focussed on the recultivation (reclamation) of post-mining landscapes in the Lusatian lignite mining district of the former German 2 Oemocratic Republic (GOR). In this area, about 700 km have been devastated by open- cast mining during the last 70 years. Therefore, the research into recultivation has a long tradition in Lusatia, going back to the 1930's. Oue [0 the scientific isolation of the former GOR, most of the research results were not available to an international audience until now. This situation holds also true for other eastern countries. Hence, this special volume is a first step to fill this gap. The papers by Pietsch, Heinsdorf, and Katzur and Haubold-Rosar detail the Lusatian lignite mining district presenting an overview of recultivation research results and practical experiences related to the establishment of terrestrial and aquatic ecosystems in this region after mining. In particular, the amelioration and reforestation of extremely acid, sulfurous mine soils, the fertilization of forest stands under different mine site conditions and the site-specific recolonization and re vegetation strategies are described.

This special volume contains papers that are partly based on contributions to the symposium "Minesite Recultivation" wh ich was held at the Brandenburg Technical University in Cottbus, FRG in lune 1994. Ouring this symposium, various aspects of research into the recultivation of open-cast minesites were discussed. As a prime example, the symposium focussed on the recultivation (reclamation) of post-mining landscapes in the Lusatian lignite mining district of the former German 2 Oemocratic Republic (GOR). In this area, about 700 km have been devastated by open- cast mining during the last 70 years. Therefore, the research into recultivation has a long tradition in Lusatia, going back to the 1930's. Oue [0 the scientific isolation of the former GOR, most of the research results were not available to an international audience until now. This situation holds also true for other eastern countries. Hence, this special volume is a first step to fill this gap. The papers by Pietsch, Heinsdorf, and Katzur and Haubold-Rosar detail the Lusatian lignite mining district presenting an overview of recultivation research results and practical experiences related to the establishment of terrestrial and aquatic ecosystems in this region after mining. In particular, the amelioration and reforestation of extremely acid, sulfurous mine soils, the fertilization of forest stands under different mine site conditions and the site-specific recolonization and re vegetation strategies are described.

Boreal forests form Earth's largest terrestrial biome. They are rich in ecosystem and landscape diversity, though characterized by relatively few plant species, as compared to other forested regions. The long term viability and sustainability of boreal forests is influenced by many factors. They are subject to interruptions at intervals by large-scale natural disturbances, and increasingly by human activities. Boreal ecosystem development is typically a slow process; hence rapid changes in the global environment may invoke complex responses. Many industrial nations border, or lie within, boreal regions, deriving much of their economic wealth and culture from the forests. The response of boreal forests to changes in the global environment - whether caused by direct human activity or by indirect changes such as the anticipated changes in climate - are therefore of considerable international interest, both for their policy implications and their scientific challenges. This book which contains almost 50 peer-reviewed papers from a world-wide group of experts assembled under the auspices of IBFRA, the International Boreal Forest Research Association, covers topics which will stimulate further research and the development of constructive policies for improved management and conservation of global boreal forest resources.

The proceedings of a special technical session dealing with the addition of Ca based materials to waters and soils for the purpose of restoring or enhancing fisheries in acidified waters are contained in this volume. The session was part of the North American Fisheries Society's annual meeting sponsored by the Water Quality Section of the Society. While the concept of liming is not new, the extent of the recent research, demonstrations and applications reported at the conference is enlightening. Six countries are represented by government, state and private sector participants. The scope of activities reported in the following 23 papers range from the simple to the very complex addition of liming materials to ponds, lakes, streams and watersheds. This volume of presentations is broad and impressive as are the methods used in the actual application of the neutralizing materials. Those programs that are demonstration application oriented are deploying techniques that are either new or modifications of existing technology.

Most of the attention with respect to the increase in atmospheric greenhouse gas concentrations centers around three issues: human-generated sources of carbon, mostly from burning fossil fuels; tropical deforestation, which accelerates the production of atmospheric carbon while causting havoc with biodiversity and the economic development of tropical countries; and the temperature increase that may accompany increased atmospheric greenhouse gas concentrations. This is the first book to focus extensively on the reverse to emissions of carbon dioxide (CO2), i.e. the sequestering of atmospheric carbon by aquatic and terrestrial ecosystems. Natural ecosystems are currently sequestering carbon and it is economically feasible to manage existing and additional terrestrial (forest, soil, saline land) and aquatic (coastal, wetland and ocean) ecosystems to substantially increase the level of carbon storage. The prospect of managing natural systems to absorb additional carbon should begin to change the mindset under which scientists, policy makers and society deal with the issue of further greenhouse gas increases.

This volume presents the work carried out by eight working groups at a meeting held in Bad Harzburg, Germany, in March 1993, to develop an assessment of the present and likely future carbon fluxes associated with the major components of the Earth's terrestrial biosphere. Major topics considered were: global carbon cycle; boreal forests and tundra; temperate forests; tropical forests; grasslands, savannas and deserts; land and water interface zones; agroecosystems; and biomass management.