Comparison of Constructed Wetlands to a Preservation Wetland in the Nashville Basin, Tennessee (USA)

Wetland restoration projects are monitored to verify wetland function. Two constructed wetlands were compared with an onsite preservation wetland in the Nashville Basin, TN (U.S.) based on shallow groundwater wells, wetland determination forms, and Indicator of Reduction in Soil (IRIS) tubes data collected from 2013-2017. Results from Multiple Factor Analysis indicate that the constructed wetlands become more similar to the preservation wetland over the course of five years after construction. Shallow groundwater wells reported similar data in 42, 67, 63, and 55% of the growing season in 2013, 2014, 2015, and 2017, respectively. IRIS tubes documented the successful creation of aquic and hydric soil conditions in the created wetlands in 2016 and 2017. IRIS tube and groundwater monitoring well data indicate the duration of saturation required for developing reducing conditions decreases from 20 to 7 days as the growing season progresses. Hydrophytic vegetation was present during the course of this study. After five years of monitoring, the constructed wetlands are more similar to the preservation wetland, although the constructed wetlands still lacked the tree strata.