Field studies of pollutant removal from nursery and greenhouse runoff by constructed wetlands.

Plant nursery runoff commonly contains pesticides and nutrients that often threaten aquatic ecosystems. Constructed wetlands could be a tool to remove pesticides and nutrients from nursery runoff but have not been extensively studied in this setting. Two field-scale constructed wetlands (one subsurface-flow constructed wetland [SFCW] and one free-surface constructed wetland [FSCW]) were implemented and monitored for water quality improvement. The SFCW demonstrated significant mass reduction of 78% or greater for nitrate, orthophosphate, total nitrogen, total phosphorus, and total suspended solids. The SFCW also demonstrated significant mass reduction of 79% or greater for 10 of the 12 pesticide compounds detected in over half of the collected samples. The FSCW demonstrated significant mass reduction of 46% or greater for all nonpesticide analytes except total nitrogen. Loading rate and actual storage volume compared with inflow volume likely affected performance. Reduced size and increased loading rate of the FSCW likely reduced its ability to effectively reduce pesticides. Results from this study indicate that constructed wetlands are likely an effective tool for nursery runoff management. When designing and implementing constructed wetlands, it is important for practitioners to consider the tradeoff between system size (additional cost and land otherwise dedicated to production) and performance.

Critical Review of Technical Questions Facing Low Impact Development and Green Infrastructure: A Perspective from the Great Plains.

Since its inception, Low Impact Development (LID) has become part of urban stormwater management across the United States, marking progress in the gradual transition from centralized to distributed runoff management infrastructure. The ultimate goal of LID is full, cost-effective implementation to maximize watershed-scale ecosystem services and enhance resilience. To reach that goal in the Great Plains, the multi-disciplinary author team presents this critical review based on thirteen technical questions within the context of regional climate and socioeconomics across increasing complexities in scale and function. Although some progress has been made, much remains to be done including continued basic and applied research, development of local LID design specifications, local demonstrations, and identifying funding mechanisms for these solutions. Within the Great Plains and beyond, by addressing these technical questions within a local context, the goal of widespread acceptance of LID can be achieved, resulting in more effective and resilient stormwater management.