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Evaluation of ecosystem services in subsurface-drained agricultural catchments that include water quality wetlands in the upper Midwest, USA
Citation:
Forshay, Ken, T. Newcomer-Johnson, M. Mitchell, AND Chris Taylor. Evaluation of ecosystem services in subsurface-drained agricultural catchments that include water quality wetlands in the upper Midwest, USA. U.S. EPA Office of Research and Development, Washington, DC, EPA/600/F-20/444, 2021.
Impact/Purpose:
Nutrients that are lost from soils in the Midwest may make their way to the Gulf of Mexico where they can contribute to algal blooms and subsequent reductions in habitat quality, fish production, and recreation. The state of Iowa plans to reduce nutrient losses by 45%, with wetlands constructed to intercept water draining from agricultural fields likely playing a key role. These water quality wetlands remove nutrients from drainage water while also providing habitat for a variety of organisms. Additionally, much of the fertile upper Midwest, including Iowa, has poor-draining agricultural soils. Artificial drainage systems were installed to reduce crop losses due to flooding, but these systems are now either under designed or failing and require widespread improvements. Unfortunately, the effects of drainage improvements on water quality and greenhouse gas emissions are not well known, especially when paired with a water quality wetland and evaluated across the entire agricultural- water quality wetland system. This technical fact sheet highlights an ongoing investigation of the potential ecological benefits that result from the installation of water quality wetlands in agricultural landscapes with and without drainage improvements. This project and fact sheet will be of interest to land managers and landowners looking to optimize crop production, reduce nutrient pollution, reduce greenhouse gas emissions, and provide habitat and recreational opportunities. Further, the fact sheet highlights a collaboration between EPA’s ORD and Office of Water, EPA Region 7, the Iowa Department of Agriculture, Iowa Farm Bureau, Agribusiness Association of Iowa, Iowa State University, Iowa Department of Agriculture and Land Stewardship, and the Iowa Department of Natural Resources.
Description:
The state of Iowa plans to reduce nutrient loads from agricultural systems by 45%. At the same time, many landowners in the state are dealing with failing or under designed subsurface drainage systems that result in crop yield reductions. Water quality wetlands, constructed to intercept tile-drain flows at the catchment outlet, represent a potential solution for reducing nutrient loading while also providing habitat and other ecosystem services. ORD, Region 7, and our collaborators in Iowa are working to model crop yields and the net catchment-scale ecosystem services resulting from scenarios with and without drainage improvements and water quality wetlands. Results from this study will inform management decisions with the goal of optimizing systems for crop yields, water quality, and other ecosystem services such as greenhouse gas regulation, habitat, and recreational services.