Physical modelling is an established technique for hydraulic research. It bridges the gap between what can be simulated accurately using numerical models and the real world. It also facilitates the calibration of numerical models and increases confidence in future predictions. These are vital given the present need to understand and adapt to the impacts of climate change. Worldwide it has been estimated that more than 2.75 billion people will live within 95 km of the coasts by the year 2025 (Science Daily, July 18 2006, Center for Climate Systems Research). Added to this is the impact of history that dictates that the majority of cities and towns are situated on rivers which have long been prime sources of water, waste disposal, food and transport. This growing section of the population are susceptible to the effects of changes in both rainfall patterns and sea level which control both the frequency and scale of river and coastal flooding and the rates of coastal erosion. It is therefore imperative that we find ways of predicting the consequences of future changes in river and coastal systems. This can only be achieved through modelling – and most predictions are now based on numerical models. However, such models are only as good as assumptions and data on which they are based. Physical models are one of the most cost-effective ways of providing these data. Physical hydraulic models which are well founded and controlled laboratory experiments simulating hydraulic systems are therefore important to both our present and future research needs. This book is designed to act as a guide to best practice in this type of laboratory experimentation. It encompasses work carried out during the Integrated Infrastructure Initiative project HYDRALAB III of the European Community’s Sixth Framework Programme.