Using wetlands to reduce nutrient loadings to rivers and the coast

Hosted by the US Environmental Protection Agency

1. Scaling wetland-mediated nutrient reductions to large watersheds and river basins 

Wetland restoration and construction are important land management options for retaining nitrogen and phosphorus, thereby improving water quality locally, such as in streams. However, little is known about the cumulative influence of wetlands outside of floodplains, i.e., non-floodplain wetlands (NFW), on surface water quality at large scales. This presentation will discuss research (1) assessing the potential for NFWs to reduce nitrate within small subbasins of the Upper Mississippi River Basin (UMRB) as well as at the river basin’s outlet, (2) exploring what NFW and NFW catchment characteristics influence nitrate reductions at these spatial scales, and (3) quantifying how far downstream NFW-mediated nitrate reductions are realized. 

Presenter: Heather Golden, Ph.D. (EPA’s Office of Research and Development)    

Heather is a Research Physical Scientist at US EPA’s ORD Center for Environmental Measurement and Modeling, in Cincinnati, Ohio. She holds a Ph.D. in forest hydrology and watershed management from the State University of New York College of Environmental Science & Forestry. Her research focuses on modeling watershed-scale hydrology and nutrient cycling and the effects of these processes on aquatic ecosystems. She is also an Associate Editor for Water Resources Research and Frontiers in Ecology & the Environment.   

2. Constructed wetlands for nutrient reduction at the watershed scale: linking models, design, and real-world execution 

This presentation will cover a decade-long pursuit to implement constructed wetlands for nutrient reduction from row crops (RC) in a large watershed in southwestern Ohio. Initially, nutrient reduction practices were modeled at the watershed scale and included residue management, cover crops, filter strips, grassed waterways, constructed wetlands, and reducing fertilizer. Among the scenarios modeled, constructed wetlands ranked highest for their low cost of nutrient removal. Real-world projects were designed to understand the feasibility of retrofitting the system with the necessary extent of constructed wetlands to meet a 42% target phosphorus reduction. Current wetlands construction expenditures can only achieve a portion of the required treatment. The results show the importance of considering realistic field-scale build opportunities in watershed-scale nutrient reduction simulations using constructed wetlands. 

Presenter: Christopher Nietch, Ph.D. (EPA’s Office of Research and Development)   

Chris is a Research Ecologist at US EPA’s ORD Center for Environmental Measurement and Modeling in Cincinnati, OH. He holds a Ph.D. in biological and marine sciences from the University of South Carolina. His research focuses on the implementation of nutrient pollution reduction programs and practices in watersheds and harmful algal bloom ecology and risk assessment. He also directs research at the US EPA’s Experimental Stream Facility where he leads ecotoxicology studies focusing on stressor impacts on small streams.