Multitracer assessment of wetland succession: Effects on conservative and nonconservative transport processes

Abstract

Because of emerging vegetation and sedimentation processes, the succession of wetlands is a dynamic process. Hence, a noticeable impact on the functioning and the efficiency of constructed treatment wetlands regarding solute retention can be expected. Within 5 months a reduction of active wetland volume, a decrease of light decay, and an increase of sorption capacity were observed using four multitracer experiments in a newly established constructed wetland. Tracer breakthrough curves of conservative and nonconservative tracers were analyzed with the help of a transient storage model. The model characterized the impact of vegetation development and sediment accumulation on solute transport properties. Three different tracers allowed an assessment of wetland hydraulics, sorption processes, and light impact on photodegradable solutes. Finally, the exemplary transport prediction of a fourth, independent tracer that was both photodegradable and sorptive demonstrated a cost-efficient technique to determine the influence of succession processes on treatment efficiency. © 2012. American Geophysical Union. All Rights Reserved.