ABSTRACT
A wide variety of wastewaters have been treated with wetland systems. Features of water movement in these systems distinguish them from conventional concrete-and-steel wastewater treatment facilities. The purpose of this chapter is to set forth current information on key hydrologic processes, and to examine implications on process performance. Hydrologicai complexity makes design and data interpretation difficult for wetland treatment systems. Attempts to set wetland operating depths may fail if vegetative resistance creates a significant slope to the wetland water sheet. Flow through a wetland system is augmented by precipitation and (negatively) evapotranspiration. Precipitation records are available for nearby sites, and the above outlines methods for estimating evapotranspiration. The chapter addresses what effect these gains or losses have on wetland hydrodynamics. A wetland system designed without regard for atmospheric augmentation may be under- or overdesigned, depending on degree of treatment and local climatic conditions in terms of water gains or losses.
