Local Green Stormwater Infrastructure Projects and Research Findings are Highlighted through Site Visits with Practitioners

The Lake Champlain Sea Grant and Vermont Department of Environmental Conservation’s Green Infrastructure Collaborative (GIC) bridges the gap between research, extension, and application of green stormwater infrastructure (GSI) in Vermont. GSI practices, such as bioretention and stormwater wetlands, capture and treat polluted stormwater using plants and soil close to the source, rather than sending stormwater directly to water bodies, which increases the chance of flooding and other downstream impacts. Pollution from stormwater runoff can contribute to cyanobacteria blooms in Lake Champlain and other water bodies. 

On July 17, the GIC hosted over 30 stormwater partitioners for site visits to green stormwater infrastructure projects in Essex and Essex Junction. The goal was for stormwater managers, State agencies, consultants, designers, researchers, and students to learn from local experiences of implementing, researching, and maintaining GSI. 

The group visited two stormwater subsurface gravel wetlands, two sand filters, and one infiltration trench across the two municipalities. One gravel wetland was part of recent LCSG-funded research and one sand filter project was researched by a UVM team with funding from the Vermont Agency of Transportation. Both studies investigated the ability of  these projects to reduce phosphorus loads within influent stormwater to improve understanding of project design and function. At each site, research teams explained their findings to the site visit attendees. 

“I was both excited and honored to share our research findings with such a large group of local experts. The tour itself was full of great discussions and lessons,” says Micayla Schambura, UVM graduate student who researched a sand filter project in Essex. “My hope is that going forward we continue to research and implement stormwater treatment practices that consider resource recovery and circular economy in their designs.” 

Researchers looked closely at the soils utilized in these projects. Gravel wetlands require an organic soil media to sustain plantings, but if that media contains an excess of nutrients, it can be a source of pollution, particularly phosphorus. Researchers recommend using on-site soil media when possible and testing the soil media as described in this document.

Sand filters have been implemented as a stormwater treatment practice for a long time, but the novel piece of the study was the addition of drinking water treatment residuals (a waste byproduct) to target dissolved phosphorus in place of alternative expensive materials. Previous UVM research demonstrated their ability to capture dissolved phosphorus in bioretention systems and simulated lab experiments prior to this study. 

During the site visits, managers shared their experience overseeing these projects, working with residents, and maintaining them, which are essential factors to ensuring long-term successful projects. 

“I like hearing about the imperfect projects and where challenges have been with maintenance and monitoring,” one participant reflected. “Those teach great lessons learned and help identify areas for research/improvement.” 

Essex and Essex Junction are both communities that must manage stormwater due to the municipal separate sewer system (MS4) permit. In Vermont, many MS4 communities have implemented GSI practices to comply with permit regulations. These events are an opportunity to bring practitioners together and learn from each other so we can all continue to improve stormwater management across the state. 

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 Jill.Sarazen [at] uvm.edu (reach out to Jill Sarazen )to partner with Lake Champlain Sea Grant!