The tropical north of Australia covers almost half of the countrys total land area, is occupied by no more than about 5% of the total population, and yet has been estimated to account for close to 70% of the countrys potential freshwater resources. The region experiences strong climatic variability, both spatially and seasonally, with large areas subject to long dry periods interspersed by short periods of torrential rain. This book presents an overview of the freshwater resources of a region that has undergone a period of intense development (agricultural, industrial and social) over recent decades and for which is predicted a continuing period of development into the future. The author describes how the availability of surface, groundwater and stored freshwater, in terms of both quantity and quality, will continue to be the major factor influencing such development. It will also highlight how the emphasis on ensuring year-round water supply has, in recent decades, shifted to one of management to ensure sustainability of this vital resource and maintenance of the ecological health of what is known to be a fragile ecosystem. This book draws on the authors 25+ years of experience as a professional biologist living and working (as a teacher/researcher) in the tropical north of Australia, a region which in light of strengthening trade and other links between Australia and its neighbouring south-east Asian countries, is likely to become of increasing international significance in the future.