This book appears a century after the discovery of radioactivity. It was in 1896, when Henri Becquerel reported his first results about the penetrating radiation, which could darken the packed photographic plates. The initial fascination of radioactivity, e.g., the discovery of new radioactive elements, the first real description of the structure of atoms and their nuclei, the applications of radiotracers, the high sensitivity of activation analysis, etc., was followed by the use of atomic bomb in 1945. The mushroom cloud became a symbol of destructive nuclear power. And even nuclear energy production (which provides about 20% of the world's electricity) is overshadowed by radioactive waste. However, the latest results suggest that the Accelerator-Driven Transmutation Technology (ADTT) will solve this problem, since this technique can decrease the lifetime of the fission products comparatively to the human lifespan. Practical control of fusion may also be possible in the first decades of the next millennium.

Environmental Tracers in Subsurface Hydrology synthesizes the research of specialists into a comprehensive review of the application of environmental tracers to the study of soil water and groundwater flow. The book includes chapters which cover ionic tracers, noble gases, chlorofluorocarbons, tritium, chlorine-36, oxygen-18, deuterium, and isotopes of carbon, strontium, sulphur and nitrogen. Applications of the tracers include the estimation of vertical and horizontal groundwater velocities, groundwater recharge rates, inter-aquifer leakage and mixing processes, chemical processes and palaeohydrology. Practicing hydrologists, soil physicists and hydrology professors and students will find the book to be a valuable support in their work.

Mathematical modelling has become an indispensable tool for engineers, scientists, planners, decision makers and many other professionals to make predictions of future scenarios as well as real impending events. As the modelling approach and the model to be used are problem specific, no single model or approach can be used to solve all problems, and there are constraints in each situation. Modellers therefore need to have a choice when confronted with constraints such as lack of sufficient data, resources, expertise and time.

Environmental and Hydrological Systems Modelling provides the tools needed by presenting different approaches to modelling the water environment over a range of spatial and temporal scales. Their applications are shown with a series of case studies, taken mainly from the Asia-Pacific Region. Coverage includes:

• Population dynamics
• Reaction kinetics
• Water quality systems
• Longitudinal dispersion
• Time series analysis and forecasting
• Artificial neural networks
• Fractals and chaos
• Dynamical systems
• Support vector machines
• Fuzzy logic systems
• Genetic algorithms and genetic programming

This book will be of great value to advanced students, professionals, academics and researchers working in the water environment.

Soil science is perhaps one of the oldest practical sciences, having been of concern to man probably from the time he progressed from a strictly preda tory life to one in which agriculture became important. In view of the anti quity of concern with the subject, it is perhaps surprising that it can be approached from a fresh viewpoint, as is done in this book. Because soil science is an applied science, it is not surprising that the approach is usually descriptive, rather than imaginative. For agriculturalists and other land users, perhaps the most important part of soil science is the description of soils and the capacities of such soils to maintain crops, and this is reflected by the fact that soil science is usually treated ima highly descriptive manner, with soil classification being one of the main efforts. The treatment of the subject from a geological point of view, with considerable emphasis on the evolution of soils and the reasons governing their composition and form, makes this a highly readable book. Books on soil science are timely, with present-day concern with such major problems as the pollution of our environment and the possibility of overreaching our capacity for producing food for an expanding population.

Floods constitute a persistent and serious problem throughout the United States and many other parts of the world. They are respon sible for losses amounting to billions of dollars and scores of deaths annually. Virtually all parts of the nation--coastal, mountainous and rural--are affected by them. Two aspects of the problem of flooding that have long been topics of scientific inquiry are flood frequency and risk analyses. Many new, even improved, techniques have recently been developed for performing these analyses. Nevertheless, actual experience points out that the frequency of say a 100-year flood, in lieu of being encountered on the average once in one hundred years, may be as little as once in 25 years. It is therefore appropriate to pause and ask where we are, where we are going and where we ought to be going with regard to the technology of flood frequency and risk analyses. One way to address these questions is to provide a forum where people from all quarters of the world can assemble, discuss and share their experience and expertise pertaining to flood frequency and risk analyses. This is what constituted the motivation for organizing the International Symposium on Flood Frequency and Risk Analyses held May 14-17, 1986, at Louisiana State University, Bat-on Rouge, Louisiana."

This volume arises from the work of the International Geographical Union Working Group on Regional Hydrological Response to Climate Change and Global Warming under the chairmanship of Professor Changming Liu (1992-96). The book consists mostly of peer-reviewed papers delivered at the Working Group's first three scientific meetings held in Washington, D.C. (1992), Lhasa, Tibet (1993) and Moscow (1995). These have been supplemented by a few additional chapters that have been specifically commissioned in order to give a well-rounded coverage of the global and scientific aspects of the topic. As editors, we have sought to balance state-of-the-art reviews of methodology and regional research with detailed studies of specific countries and river basins. In the spirit of the IGU, we have devoted particular effort to encouraging contributions from scientists in the non-English-speaking world. These chapters provide valuable evidence of recent climatic change and predictions of future hydrological impacts from parts of the world where little detailed work has been conducted hitherto. They provide much valuable information that is new and interesting to an international audience and is otherwise very difficult or impossible to acquire. It is hoped that the present volume will be not only a record of current achievements, but also a stimulus to further hydrological research as the detail and spatial resolution of Global Climate Models improves. One notable aspect that emerges from a number of the contributions is that many, though by no means all, recent hydrological trends are in line with global warming predictions.

P. G. Sly Canada Centre Inland Waters, P.O. Box 5050, Burlington, Ontario L7R 4A6, Canada Keywords: symposium, sediments, freshwater Following the highly successful First Symposium work of the symposium: on Research into the Interactions between Sedi- I. Summary of sediment dynamics and distribu- ments and Freshwater held in Amsterdam, in 1976, tion in fluvial and lacustrine environments. it was decided that a second symposium in this 2. Land use effects on sediment yields,and quality. series should be held to continue the discussions on 3. Sediments in mass balance models, including progress in this rapidly expanding field of aquatic total loadings. science. The Second Symposium was held at 4. Sediments as concentrating mechanisms of nat- Queen's University, Kingston, Ontario, between 15 ural and anthropogenic, organic and inorganic and 18 June 1981. It was originally intended to hold materials. the meeting in Toronto a year earlier, but because 5. Release mechanisms, and transfer to biosystem, of difficulties in planning and the high cost of ac- from bed and suspended solids. commodation it was necessary to revise the original 6. Short- and long-term dating methods, spatial program and schedule. and temporai consistency, bioturbation and dif- The symposium received generous support from fusion.

Fluvial Geomorphology of Great Britain studies the development of river-made land forms, together with the associated fluvial processes. There are many sites of scientific interest and value throughout the UK. The GCR sites described in this volume represent the wide range of fluvial land forms in the UK, and the accounts provide scientific descriptions of all the fluvial geomorphology sites in Britain selected for statutory nature conservation as SSSIs.

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.

Is it not generally believed that our town is a healthy place . . . a place highly com mended on this score both for the sick andfor the healthy? . . And then these Baths - the so-called 'artery' of the town, or the 'nerve centre' . . . Do you know what they are in reality, these great and splendid and glorious Baths that have cost so much money? . . A most serious danger to health! All that filth up in Melledal, where there's such an awful stench - it's all seeping into the pipes that lead to the pump-room! Henrik Ibsen, An Enemy of the People, 1882 Henrik Ibsen gave the 'truth about mineral water' more than 100 years ago in An Enemy of the People. His examples came not from the decadent bathing spas of Bohemia or Victorian Britain, but from the very edge of polite society, subarctic Norway! His masterpiece illustrates the central role that groundwaters and, in particular, mineral waters have played in the history of humanity: their economic importance for towns, their magnetism for pilgrims searching for cures, the political intrigues, the arguments over purported beneficent or maleficent health effects and, finally, their contami nation by anthropogenic activity, in Ibsen's case by wastes from a tannery. This book addresses the occurrence, properties and uses of mineral and thermal groundwaters. The use of these resources for heating, personal hygiene, curative and recreational purposes is deeply integrated in the history of civilization.

In diamond alluvial deposits, the information about the spatial distribution of stone size is of crucial importance for the quantitative characterisation of the different areas of the deposit. In fact, the value of the diamond reserves depends strongly on the distribution of stone sizes: between two areas with the same grade, the most valuable is the one with larger stones. The geological genesis of the mineralization, related with the transport and deposition of stones in trapsites, can create separated spatial areas, corresponding to different stone size. To characterise these distinct areas, the non smooth transitions between them should be accounted for, in the estimation of internal properties. An extended version of zonal control of geostatistical estimation (Soares et ai, 1995) proposed in this paper, aims to characterising the classes of size histogram for each geological unit, avoiding the smooth effect. For this purpose the morphology of each geological unit is obtained by using two distinct criteria: i) first, the points of each unit are classified according to the local and global probabilities of belonging to each unit (Soares, 1992); ii) in a second classification, the optimization technique of Simulated Annealing is used to rearrange the pre-classified points in order to impose, in the final morphological maps, the spatial variability of experimental samples (Goovaerts, 1994). A case study of a diamond alluvial deposit with two geological units with distinct stone size histograms is presented.

This Topics volume is devoted to a study of sound propagation in the ocean. The effect of the interior of the ocean on underwater sound is analogous to the effect of a lens on light. The oceanic lens is related, as in light propagation, to the index of refraction of the medium. The latter is giv n by the ratio of the sound frequency to the speed of sound in water, typi ca lly about 1500 m s -1. It is the vari ation of the sound speed due to changing temperature, density, salinity, and pres sure in the complex ocean environment which creates the lens effect. Many oceanic processes such as currents, tides, eddies (circulating, translating regions of wa ter), and internal waves (the wave-like structure of the oceanic density variabil ity) contri bute in turn to the changes in sound speed'. The net effect of the ocean lens is to trap and guide sound waves in a channel created by the lens. The trapped sound can then propagate thousands of miles in this oceanic waveguide. In addition to the propagation in the interior of the ocean, sound can propagate into and back out of the ocean bottom as well as scatter from the ocean surface. Just as the sound produced by a loudspeaker in a room is affected by the walls of the room, so the ocean boundaries and the material properties below the ocean bottom are essential ingredients in the problem."

Since the landmark contributions of C. E. Shannon in 1948, and those of E. T. Jaynes about a decade later, applications of the concept of entropy and the principle of maximum entropy have proliterated in science and engineering. Recent years have witnessed a broad range of new and exciting developments in hydrology and water resources using the entropy concept. These have encompassed innovative methods for hydrologic network design, transfer of information, flow forecasting, reliability assessment for water distribution systems, parameter estimation, derivation of probability distributions, drainage-network analysis, sediment yield modeling and pollutant loading, bridge-scour analysis, construction of velocity profiles, comparative evaluation of hydrologic models, and so on. Some of these methods hold great promise for advancement of engineering practice, permitting rational alternatives to conventional approaches. On the other hand, the concepts of energy and energy dissipation are being increasingly applied to a wide spectrum of problems in environmental and water resources. Both entropy and energy dissipation have their origin in thermodynamics, and are related concepts. Yet, many of the developments using entropy seem to be based entirely on statistical interpretation and have seemingly little physical content. For example, most of the entropy-related developments and applications in water resources have been based on the information-theoretic interpretation of entropy. We believe if the power of the entropy concept is to be fully realized, then its physical basis has to be established.

In the book's four Parts, the interdisciplinary approach to many issues contributes to the relationship between water and poverty. Part I includes articles on the conceptual and methodological issues concerning poverty reduction through water resources development. It also offers analysis of quantitative measurements of poverty reduction, including some approaches for creating a Water Poverty Index. Part II considers the institutional frameworks for management of water and poverty reduction. Topics range from community-based decision making to international leadership. Part III encompasses discussions on participatory irrigation management and the privatization of urban water supplies and sewerage and the link to poverty. Case studies from India, Turkey, and Jordan make up Part IV. The studies present diverse water management and development practices for poverty reduction, including realistic pricing and effective irrigation practices, the use of water as an engine for sustainable development, small and large scale strategies for reducing the risks and uncertainties in water availability and food security, the economic value of improved water supplies, and the positive impact of small-scale development projects.

To honour the remarkable contribution of Michel David in the inception, establishment and development of Geostatistics, and to promote the essence of his work, an international Forum entitled Geostatistics for the Next Century was convened in Montreal in June 1993. In order to enhance communication and stimulate geostatistical innovation, research and development, the Forum brought together world leading researchers and practitioners from five continents, who discussed-debated current problems, new technologies and futuristic ideas. This volume contains selected peer-reviewed papers from the Forum, together with comments by participants and replies by authors. Although difficult to capture the spontaneity and range of a debate, comments and replies should further assist in the promotion of ideas, dialogue and criticism, and are consistent with the spirit of the Forum. The contents of this volume are organized following the Forum's thematic sessions. The role of theme sessions was not only to stress important topics of tOday but in addition, to emphasize common ground held among diverse areas of geostatistical work and the need to strengthen communication between these areas. For this reason, any given section of this book may include papers from theory to applications, in mining, petroleum, environment, geohydrology, image processing.

Since 1956 the author has been making extensive and detailed investigations of saline lakes on the Qinghai-Tibet plateau. On the basis of large amounts of reliable first-hand data and multidisciplinary analysis, the book deals with the temporal-spatial evolution of the plateau saline lakes and the prospects for inorganic salts and organic resources and their exploitation and protection, as well as the relationships between saline lakes and global changes. This book is the first English monograph on saline lakes on the Qinghai-Tibet Plateau - the Roof of the World'. Compared with books about saline lakes in other areas of the world, this monograph is written in a multidisciplinary, comprehensive and systematic way. It may be used by graduate students, teachers, researchers, field geologists and engineers as a reference book in research, teaching, etc.

It is well known that the interactions between land surfaces and the atmosphere, and the resulting exchanges in water and energy have a tremendous affect on climate. The inadequate representation of land-atmosphere interactions is a major weakness in current climate models, and is providing the motivation for the HAPEX and ISLSCP experiments as well as the proposed Global Energy and Water Experiment (GEWEX) and the Earth Observing System (EOS) mission. The inadequate representation reflects the recognition that the well-known phys ical relationships, which are well described at small scales, result in different relationships when represented at the scales used in climate models. Understanding this transition in the mathematical relationships with increased space-time scales appears to be very difficult, and has led to different approaches; at one extreme, the famous "bucket" model where the land-surface is a simple one layer storage without vegetation; the other extreme may be Seller's Simple Biosphere Model (Sib) where one big leaf covers the climate model grid. Given the heterogeneous nature of landforms, soils and vegetation within a climate model grid, the development of new land surface parameterizations, and their verification through large scale experiments is perceived to be a challenging area of research for the hydrology and meteorology communities. This book evolved from a workshop held at Princeton University to explore the status of land surface parameterizations within climate models, and how observa tional data can be used to assess these parameterizations and improve models."

In 1998 Armenia was commemorating the tenth anniversary of the catastrophic Spitak earthquake. The Second International Conference on "Earthquake Hazard and Seismic Risk Reduction" sponsored by the Government of the Republic of Armenia and United Nation's International Decade for Natural Disaster Reduction (UN/IDNDR) was held in dedication to that event between 14-21 September (later referred to as Yerevan Conference). The Yerevan Conference has been organized by the National Survey for Seismic Protection (NSSP) of the Republic of Armenia. All level's decision-makers (from the ministers to the local authorities), politicians, scientists, leaders of the executive and legislative powers, psychologists, leading businessmen, representatives from the private sector and the media as well as from the International Organizations have been invited by the Armenian NSSP to take part in joint discussion of the Seismic Risk Reduction Problem for the first time in the history of such forums. Armenian NSSP's such initiative has been triggered by the experience of the Spitak earthquake and other disasters. They showed that it will be possible to reduce the risks, posed by the natural disaster, only through the common efforts of all the community in co-operation with the International institutions.

The fonner Egyptian Minister of State for Foreign Affairs and fonner UN Secre tary General, Butros Butros Ghali stated after the second Gulf War "The next war in the Middle East will not be fought for oil, but for water. " This famous statement has been echoed by many politicians: shortly before be coming president of Turkey, SOleyman Demirel declared that the waters of the Euphrates and Tigris belonged to Turkey, just as oil belongs to the Arabs. Rafael Eytan, at that time and now again Israeli Minister of Agriculture, declared in 1990 in full-page advertisements in the Jerusalem Post that Israel would never cede the West Bank to the Palestinians because Israel's water supply would otherwise be endangered. Finally, Ismail Serageldin, vice president of the World Bank, declared in 1995 that "the wars of the next century will be over water." These statements are typical of the atmosphere reigning in the Middle East and in several other places around the world concerning the issue of international fresh water resources. Whether these perceptions correspond to an actual threat to a nation's water supply or whether they correspond to the official position of states in negotiations often conducted secretly, is an entirely different matter. A closer analysis of the issue of international fresh water resources, as we attempt in this book, admittedly reveals a dangerous potential for conflict over water."

Acidification is a universal problem at all mining sites in which oxygenated water comes in contact with sulfide minerals or other reduced sulfur compounds. An International Workshop was held in September 1995 at the Department for Inland Water Research of the UFZ-Centre for Environmental Research in Magdeburg on the limnology of lakes created by open-cast lignite mining, emphasizing the often observed geogenic acidification after oxidation of pyrite. The volume has 25 chapters including a chapter with results of group discussions about the topics mentioned above and further problems that were identified during the meeting. The monograph gives a baseline of the state of science on the worldwide problem of geogenic acidification of lakes following human mining activities.

This book evolved from a collaborative research project between the University of Manitoba, Canada and Jahangirnagar University, Bangladesh, which commenced in 1984 to study the problems of river channel migration, rural population displacement and land relocation in Bangladesh. The study was sponsored by the International Development Research Center (IDRC), based in Ottawa, Canada. It was through this project that I started my journey into disaster research more than thirteen years ago with basically an applied problem of massive magnitude in Bangladesh. I spent two- and-a half-years, in two stages, in Bangladesh's riparian villages to collect the empirical data for this study. Then the growing disaster discourse throughout the 1980s, especially its conceptual and theoretical areas, drew me in further, gluing my interest to these issues. In the 1990s, during my research and teaching at Brandon University, Canada, I realized that, despite the large body of literature on natural disasters, there was no work that synthesized the approaches to nature-triggered disasters in a comprehensive form, with sufficient empirical substantiation. In addition, despite the great deal of attention given to disasters in Bangladesh, I found no detailed reference book on the topic. Natural hazards and disasters, in my view, should be studied under a holistic framework encompassing the natural environment, society and individuals. Overreaction to the limitations of technocratic-scientific approaches-the control and prevention of physical events through specialized knowledge and skills-has resulted in a call for "taking the naturalness out of natural disasters.

In 1981 Chile's military government dictated a new Water Code that radically changed the country's previous water rights system by strengthening private property rights, favoring market incentives, and reducing state regulation. Against the Current: Privatization, Water Markets, and the State in Chile is the first empirical and interdisciplinary study of water markets in Chile, which is the leading international example of free market water policies. Against the Current: Privatization, Water Markets, and the State in Chile challenges the glowing reports given by neoliberals in Chile and the World Bank, showing that the results of this economic experiment have actually been rather mixed. Within the agricultural sector the Water Code has worked fairly well, although the market incentives to conserve water have been ineffective and water rights trading has been less active than expected. The Code's impact has been more negative at the level of river basins, where the institutional framework has revealed critical flaws in coordinating multiple water users and resolving conflicts. Against the Current: Privatization, Water Markets, and the State in Chile combines law, political economy, and geography to analyze the disadvantages, problems, and wider contexts of water markets. This book will appeal to everyone interested in property rights, market-friendly environmental policies, the political economy of sustainable development, and the intersection of economics with law and institutions.

On the basis of a total of thirteen case examples from the Tien Shan, Karakorum, Himalaya and Tangula Shan (central Tibet), the risk potential and hazards are inferred from the development of landscape during the Quaternary. The history of glaciers can be seen as of central importance for this. The Ice Age glacial erosion created V-shaped valleys, which with their steep flanks - as a consequence of the interglacial formation of V -valleys - have prepared and brought about landslides as well as rockslides and the hazards, combined with them. The same is true for the moraines, which the gla ciers have deposited high-up in the valley flanks and related loose stone deposits. Dry and wet mass movements follow after heavy precipitation, especially in the semi-arid investigation areas, and are catastrophes for the settlements and the communication routes in the valley floors. Their key-forms are debris cones and debris slopes, as well as mudflows and alluvial fans. In addition to the Ice Age glaciation history, as a preparatory, indirect factor, the Holocene to present glaciation history is, as a result of the danlming-up of glacier- and moraine lakes and their outbursts, a direct risk factor. The examples presented of acute and already occurred cases of damage were inves tigated in the years 1989-1994. Acknowledgements The authors wish to thank the Deutsche Forschungsgemeinschaft (DFG), the Max Planck-Gesellschaft (MPG), the Volkswagen-Stiftting (VW) and the Deutscher Aka demischer Austauschdienst (DAAD) for the financial support for the field-work."

Several important developments in our understanding of the chemistry of weathering have occurred in the last few years: 1. There has been a major breakthrough in our understanding of the mechanisms controlling the kinetics of sil icate dissolution, and there have been major advances in computer modeling of weathering processes. 2. There has been a growing recognition of the importance of organic solutes in the weathering process, and hence of the inter-relationships between mineral weathering and the terrestrial ecosystem. 3. The impact of acid deposition ("acid rain") has been widely recognized. The processes by which acid deposition is neutral ized are closely related to the processes of normal chemical weathering; an understanding of the chemistry of weathering is thus essential for predicting the effects of acid deposition. 4. More high-qual ity data have become available on the chemical dynamics of smal I watersheds and large river systems, which represent the integrated effects of chemical weathering.

In the past two decades several activities in the field of water resources management have been enhanced and intensified. This . rise had at least two independent reasons. The first and main one was the constantly increasing water demand for agriculture and industry on one side and the concern about the deteriorating environment on the other. While this last concern was lately overshadowed by deterioration of national economies, the quantity of available water resources has certainly not increased with the growing scarcity of funds for its development and protection. Furthermore, the standard of living, which raised across the world, even in India and China, countries which concentrate more than a third of the world population, has made people and their governments more aware of natural disasters caused by weather. Since a large percentage of losses in human life and material damage from weather-related disasters are caused by water, either by its excess or scarcity, the concern about water has been increasingly associated with these disasters. The second reason for intensified water resources management is man's spectacular technological advance in electronics, computers and use of satellites. The Koran says that two things cannot be predicted: the sex of the child in its mother's womb and the quantity of water that falls from the sky and flows in rivers. Technological progress has disproved both of these caveats.