ABSTRACT

This chapter reviews the data on treatment wetland water temperatures and explores the tools available to wetland designers to predict water temperatures that result from energy flows within treatment wetlands. Water temperatures in treatment wetlands are driven by energy flows that act on the system. As water flows through the wetland, energy gains and losses drive the water temperature towards a balance point temperature, at which energy gains equal energy losses. Convection and diffusion carry water away from the surface, and transfer heat from the air to the wetland. For water vapor transport, the driving force is the water partial pressure difference between the wetland and the air above Heat may enter or leave the wetland surface water from the underlying soils, via the process of heat conduction. Wetland water temperatures are determined by the wetland energy balance, which also contains a strong dependence on the latent heat of the evaporating water.