Despite the mechanisms of reservoir sedimentation being well known for a long time, sustainable and preventive measures are rarely taken into consideration in the design of new reservoirs. To avoid operational problems of powerhouses, sedimentation is often treated for existing reservoirs with measures which are efficient only for a limited time. The today's challenge of dam owners and engineers is to guarantee with adequate mitigation measures the future sustainable use of the vital reservoirs supplying water for drinking, food and energy production. Research and development is still urgently needed to identify efficient mitigation measures adapted to the main sedimentation processes involved in reservoirs. During the seventh International Conference on Fluvial Hydraulics "River Flow 2014" at Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland, scientists and professionals from all over the world addressed the challenge of reservoir sedimentation in a special session and exchanged their knowledge and experiences. Invited and selected contributions, which give an overview on the latest developments and research regarding reservoir sedimentation including case studies, are presented in this book, in the hope that they can contribute to better sustainable use of the vital reservoirs worldwide.

Dam engineering is currently experiencing a strong revival of labyrinth oriented weirs. Labyrinth weirs, with a repetitive constructional character and an increased specific discharge capacity, are a very good technical-economical compromise. The concept of Piano Key Weir (PKW), with alveoli developed in overhangs from a reduced support area, enables the installation of non-linear crests at the top of concrete dams. As a result it eliminates the main drawback of classical labyrinth weirs, and enables their use to rehabilitate numerous existing dams. Since the first implementation of piano key weirs by Electricite de France on Goulours dam (France) in 2006, at least eight PKWs have been built in France, Vietnam and Switzerland. Their operation over a few years has already provided the first prototype data. Other projects are under study, construction or planning in varied countries. On another hand, research programs are under progress all over the world. Following a first edition in 2011, Labyrinth and Piano Key Weirs II - PKW 2013 collects up-to-date contributions from people with various backgrounds, from engineers and researchers to academics. Summarizing the last developments on labyrinth oriented weirs, the book constitutes the state-of-the-art in research and application of piano key weir solutions, and will be invaluable to professionals and scientists interested in Dams Engineering.

Since the first implementation by Electricite de France on the Goulours dam (France) in 2006, the Piano Key Weir has become a more and more applied solution to increase the discharge capacity of existing spillways. In parallel, several new large dam projects have been built with such a flood control structure, usually in combination with gates. Today, more than 25 Piano Key Weirs are in operation or under construction all over the world. More than 15 years of research and development have enabled detailed investigations of the hydraulic and structural behaviour of the Piano Key Weir complex structure and have provided more and more accurate design equations. Following the proceedings of the first two workshops held in Liege (Belgium - 2011) and Paris (France - 2013), Labyrinth and Piano Key Weirs III collects the contributions presented by people with varied background, from researchers to practitioners, at the 3rd International Workshop on Labyrinth and Piano Key Weirs - PKW 2017 (22-24 February 2017, Qui Nhon, Vietnam). The papers, reviewed and accepted by an International Scientific Committee, summarize the current state-of-the-art on Piano Key Weirs from a theoretical to a practical point of view, and present most of the main projects in operation or under construction. Labyrinth and Piano Key Weirs III is thus a reference for students, practitioners and researchers interested in Dams Engineering.

Hydraulic engineering of dams and their appurtenant structures counts among the essential tasks to successfully design safe water-retaining reservoirs for hydroelectric power generation, flood retention, and irrigation and water supply demands. In view of climate change, especially dams and reservoirs, among other water infrastructure, will and have to play an even more important role than in the past as part of necessary mitigation and adaptation measures to satisfy vital needs in water supply, renewable energy and food worldwide as expressed in the Sustainable Development Goals of the United Nations. This book deals with the major hydraulic aspects of dam engineering considering recent developments in research and construction, namely overflow, conveyance and dissipations structures of spillways, river diversion facilities during construction, bottom and low-level outlets as well as intake structures. Furthermore, the book covers reservoir sedimentation, impulse waves and dambreak waves, which are relevant topics in view of sustainable and safe operation of reservoirs. The book is richly illustrated with photographs, highlighting the various appurtenant structures of dams addressed in the book chapters, as well as figures and diagrams showing important relations among the governing parameters of a certain phenomenon. An extensive literature review along with an updated bibliography complete this book.

The behaviour of river systems is a result of the complex interaction between flow, sediments, morphology and habitats. Furthermore, rivers are often used as a source of water supply and energy production as well as a waterway for transportation. The main challenge faced by river engineers today, in collaboration with environmental and ecological scientists, is to restore the channelized rivers under the constraints of high urbanization and limited space, as well as sustainable water use. During the seventh International Conference on Fluvial Hydraulics "River Flow 2014" at Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland, scientists and professionals from all over the world addressed this challenge and exchanged their knowledge regarding fluvial hydraulics and river morphology. This book comprises the proceedings of the high quality contributions of the participants, which reflect the state-of-the-art in the fields of river hydrodynamics, morphodynamics, sediment transport, river engineering and restoration. The conference was organized under the auspices of the Committee on Fluvial Hydraulics of the International Association for Hydro-Environment Engineering and Research (IAHR). Past River Flow conferences have witnessed a significant increase in participation of our community of river engineers and researchers, confirming the need for such a forum.