Hodgins, B., B. Seipp. 2018. Bioretention System Design Specifications (Issue Paper). Center for Watershed Protection, Inc., Ellicott City, Maryland.

This paper was prepared to provide technical support for Chesapeake Bay managers and stormwater professionals implementing performance enhancing devices (PEDs) for the bioretention stormwater best management practice (BMP). The recommendations in this document relate to the development of specifications for enhanced bioretention designs and media mixes. The intent of such PEDs is to sequester higher levels of nitrogen and/or phosphorus than those currently specified in the Bay states.
This paper supplements the final report entitled, “Performance Enhancing Devices for Stormwater Best Management Practices” (Hirschman et al., 2017). The aforementioned final report summarizes the technical findings of primarily laboratory studies of PEDs specific to media amendments, the usage of an internal water storage zone in the underdrain system, and the maximization of plant uptake. This paper adds the context of evolving state design standards, fundamentals of nutrient adsorption in soils, and field studies of PEDs. Its goal is to further inform the development of bioretention designs for specific pollutants of concern.