Enhancing commonly used model predictions for constructed wetland performance: as-built design considerations

Successful performance management of constructed wetlands for water treatment requires that mathematical interactions between influent surface water and the water balance be predictable and consistent. Water inflows and outflows, as quantified by a water balance model, form the baseline for pollutant loadings of solutes and nutrients. These flows, coupled with the induced ecological and chemical interactions, affect the design and predictive performance of constructed wetlands as well as the transport and fate of contaminants. The constructed wetland’s water balance was targeted for investigation through the application of a geotechnical field data acquisition. Utilization of the as-built soil profiles and the associated hydraulic conductivity properties were used to quantify the potential influence of soil structure on the design water balance, probable quantitative contributions to the hyporheic zone and predicted effluent concentrations of BOD and ammonia.