Treatment marshes for runoff and polishing Treatment wetlands encompass a diversity of managed ecosystems and provide an array of water quality improvement mechanisms. This book explains how to calculate the pollutant removal performance of treatment marshes. It provides the basis for such calculations which reside in data acquired over many years of project experiences but primarily focuses on the latest water treatment information acquired over the past ten years. Coverage include free water surface systems (FWS) or marshes which are used for waters that are only lightly polluted. It also examines the ecological values of such marshes as part of the overall system values in addition to water quality improvement plans