A floodplain is a flat, or nearly flat, land that is adjacent to a stream or river which experiences occasional flooding (a naturally occurring process), and those who live near rivers and floodplains are especially interested in them. Historically, floodplains have been used for waste disposal, supplies, power generation, transport and food. In this book, the student or professional will find information about some floodplains around the world and their main problems, as well as some techniques used to study them. This book is divided into nine chapters, and each one aims to show some relevant studies in floodplains and lakes using assorted themes, such as: mercury speciation and bioavailability, plant-soil interactions, indicators for evaluating floodplain restoration, floodplain formation, phytoplankton community, storage and release of water, hydrogenic heavy metals and hydrodynamics.