Lake Champlain Sea Grant and Partners Educate about Green Stormwater Infrastructure Best Practices
Green Stormwater Infrastructure (GSI) practices are nature-based solutions that use vegetation and soil processes to slow, store, and infiltrate stormwater into the ground and create healthier human environments. Local communities can utilize GSI to manage stormwater in the Lake Champlain basin. More dispersed GSI across the landscape can help slow stormwater before it reaching a downstream water body, and reduce pollutants to improve water quality.
Lake Champlain Sea Grant’s Green Infrastructure Collaborative (GIC) Coordinator, Jill Sarazen, partners with city governments, the state of Vermont, and practitioners to share the best practices for GSI. The GIC works to bridge the gap between research, extension, and application of GSI through tours, research communication pieces, trainings, and mailing list.
On June 8th, Sarazen and the City of South Burlington Stormwater Department brought 25 stormwater practitioners to tour stormwater infrastructure projects. During the tour, Sarazen and Dave Wheeler, City of South Burlington Deputy Director of Water Resources, shared lessons learned after implementation, research findings from monitoring studies, and operation and maintenance (O&M) considerations.
The tour brought participants to one bioretention research project on the University of Vermont’s campus and visited eight stormwater treatment systems actively managed by the City of South Burlington, which include two gravel wetlands, four dry detention basins, one sand filter, and one stormwater pond.
The bioretention research project was constructed in 2016 at UVM Miller Farm. Bioretention is a common form of GSI designed to capture and treat runoff from impervious areas, like rooftops and pavement, using an engineered soil media and planted vegetation. Sarazen shared water quality results recorded and analyzed from storm events from 2016-2019. These data suggest nutrient removal is optimized by incorporating vegetation into design. If compost is desired, it should contain low levels of phosphorus and be used sparingly due to concerns for nutrient leaching in effluent water. More information on this project can be found in the linked peer-reviewed publications below.
Discussions at each site focused on soil media designs, plant establishment, maintenance activities, such as mowing, and pretreatment technologies.
“Being able to see real constructed projects and hear about lessons learned is invaluable and I really appreciated the opportunity to do so,” shared one of the participants on the tour.
As the first stormwater utility in the state, founded in 2005, the City of South Burlington Stormwater Department has extensive experience managing stormwater treatment practices. They have specific expertise with gravel wetlands, which are becoming more common due to their ability to treat stormwater at sites where infiltration is not feasible. These are constructed wetlands with a subsurface gravel/stone layer and a wetland soil layer that sustains plantings. Many of the projects on the tour have involved partnerships with local environmental consultants, engineers, and faculty and student researchers at UVM.
In collaboration with some of these community partners, Sarazen developed a research communication piece that shares soil media specifications and testing guidance for two common GSI systems in Vermont—gravel wetlands and bioretention cells.
The guidance is intended for designers and contractors who install these systems and was informed by the findings of a recently completed Lake Champlain Sea Grant funded project: Stormwater Subsurface Gravel Wetlands in Vermont, which thoroughly examined gravel wetlands in both field and laboratory settings.
The guidance document with soil nutrients testing information and other resources to learn about GSI can be found on the Lake Champlain Sea Grant website.
If you have ideas for other related tours that highlight successful green stormwater infrastructure practices in the Lake Champlain Basin or have questions about installing GSI, please reach out to Jill.sarazen [at] uvm.edu (Jill Sarazen) to partner with Lake Champlain Sea Grant!
Learn more about GSI from this peer-reviewed research:
Roy, Eric D., et al. 2023. “Stormwater Subsurface Gravel Wetland Hydraulics, Phosphorus Retention, and Chloride Dynamics in Cold Climates.” Environmental Science: Water Research & Technology, https://doi.org/10.1039/d3ew00062a.
Sarazen, Jillian, et al. 2022. “Nitrogen and Phosphorus Removal in a Bioretention Cell Experiment Receiving Agricultural Runoff from a Dairy Farm Production Area during Third and Fourth Years of Operation.” Journal of Environmental Quality, vol. 52, no. 1, pp. 149–160, https://doi.org/10.1002/jeq2.20434.
Shrestha, Paliza, et al. 2020. “Influence of Low-Phosphorus Compost and Vegetation in Bioretention for Nutrient and Sediment Control in Runoff from a Dairy Farm Production Area.” Ecological Engineering, vol. 150, p. 105821, https://doi.org/10.1016/j.ecoleng.2020.105821.