This proceedings, ""Environmental and Coastal Hydraulics: Protecting the Aquatic Environment"", contains papers presented at the 27th Congress of the International Association of Hydraulic Research (IAHR) entitled ""Water for a Changing Global Community."" These two volumes cover topics ranging from basic research in fluid flow, mixing, sediment transport, turbulence, and interactions among flow, sediment, vegetation, and structures to applications in contaminant transport, coastal zone management, stream habitat restoration, water quality, waterway rehabilitation, and wetlands. In addition, research and engineering methodologies such as instrumentation, measurement, physical modeling, field monitoring, and computational modeling are discussed.