In the context of this book, it involves the Sarawak River of Kuching, Sarawak as a case study on the roles of river barrages, with special emphasis on one of its minor tributary Maong River. The term "Environment Quality" is meant for the impacts of the constrained Sarawak River on the tributary Maong River, in which carries the academic credibility of this research in tributary-trunk relationships. Furher analyzed are the set of properties and characteristics that are critical in managing the environment, restoring  polluted environments and anticipating the effects of man-made changes on the environments.