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The Influence of Green Infrastructure Practices on Groundwater Quality
Citation:
Beak, D., S. Acree, M. Borst, R. Ross, AND J. Brumley. The Influence of Green Infrastructure Practices on Groundwater Quality. Groundwater Protection Council (GWPC) Annual Forum (Stormwater session), Oklahoma City, OKLAHOMA, September 15 - 17, 2019.
Impact/Purpose:
Stormwater management in urban areas has been a problem facing communities for a longtime. Stormwater can cause flooding in urban areas as well as increased discharges to surface water. Green infrastructure (GI) has been suggested as a practice to alleviate flooding risks and increased discharges. However, in many cases GI infiltrates the captured stormwater into the subsurface and the risk to groundwater quality posed by the infiltration of stormwater is poorly understood. To understand the risk to groundwater quality posed by the use of GI a comprehensive literature review was undertaken, and several studies were instituted to investigate the potential risks to groundwater quality posed by the use of GI to manage stormwater. The initial short-term results indicate that there are potential risks to groundwater quality from the use of GI to manage stormwater. Chloride in the stormwater moves rapidly to groundwater and there is potentially a build up of other contaminants in the vadose zone. The long-term risks to groundwater are not known at this time and will require more study to determine the long-term risks. The results of this study would be important for program or regional partners, state officials, tribes, local stormwater managers and the general public.
Description:
The U.S. Environmental Protection Agency (EPA) in 2013 (EPA Green Infrastructure Strategy, 2013) implemented a green infrastructure (GI) approach emphasizing the role of GI not only in reducing the volume of stormwater runoff and associated pollutant loadings, but also in creating “sustainable and resilient water infrastructure that supports and revitalizes urban communities.” The overall goal was to increase the use of constructed and natural GI into stormwater management plans and watershed/ sewershed sustainability goals. However, there is limited information on the effects of GI enhanced infiltration on groundwater quality. In 2015, EPA began a study investigating the effects of GI on groundwater quality, specifically to look at potential impacts from 1) direct contamination of groundwater by infiltrated dissolved and suspended surface contaminants; 2) indirect contamination through changing aquifer conditions that allow a potential contaminant to be mobilized; 3) interaction of infiltrated water with existing subsurface contaminants (in either soil, subsoil, or groundwater) that could alter the spatial extent of existing contamination; and 4) whether materials used in construction of the GI affect water quality. The results of this study will be presented. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.