What’s new in LID and green infrastructure for stormwater management

First, what is LID? It is a stormwater management approach that, unlike conventional stormwater management which focuses on piping stormwater away from a site to large centralized stormwater treatment areas, concentrates on controlling stormwater by using small, decentralized methods to treat stormwater close to the source. LID practices are innovative practices that manage stormwater close to its source by mimicking a site’s predevelopment hydrology and use design techniques that infiltrate, evapotranspirate, and reuse runoff.

The city of Burlington, Vermont, which is home to the University of Vermont (UVM), is ahead of the curve when it comes to innovative stormwater management. It established a dedicated city stormwater program in 2009 to address state and federal stormwater permit requirements, and requires a stormwater user fee from property owners to fund efforts to meet or exceed the city’s stormwater permit requirements. In addition, all projects that disturb more than 400 square feet of earth require review from the stormwater program, regardless of whether other city permits are required. UVM’s professors and students are researching and testing emerging technologies, and the University staff is implementing best management practices (BMPs) to prevent, control, and treat stormwater runoff on the campus.

Here are a few of the projects that stood out during our NEIWPCC travels:

Updating the permaeble pavement model. We all know that traditionally paved surfaces are impervious, so when a storm event occurs, stormwater runoff is a major concern. Permeable paving allows the movement of stormwater through the surface, reducing runoff and also trapping suspended solids and filtering pollutants from the stormwater. There have been great successes with this LID technique, but its few faults – maintenance, durability, and replacement- have made Megan Moir, Burlington’s Stormwater Coordinator, question how to improve it in its parking lot along the Lake Champlain waterfront. She is now considering the modular porous concrete that UVM has installed. Why? The porous sections are easily installed, can be removed and replaced because of their size, and can be reused at other projects if needed.

Giving trees underground space to grow. Burlington has begun a new project with the city’s Department of Parks to install a tree based stormwater system using a modular frame/deck system that supports the pavement systems and allows utilities to pass through the soil and frame structure. This new technology provides trees with essential uncompacted soil volume in a highly urbanized environment, where soil is generally very compacted due to foot and road traffic, and stormwater storage and filtration. Large trees also maintain an urban tree canopy that reduces stormwater runoff as trees intercept rainfall within their canopy and allow water to evaporate back into the atmosphere rather than reaching the city’s drainage system.

“Greening” the roof. Green roofs aren’t new, but UVM’s Rubenstein School of Environment and Natural Resources is testing out how to improve them. Green roofs create a lightweight, permeable, vegetative surface on a roof, using a variety of plants, in order to reduce heating and cooling costs, and reduce and filter stormwater runoff. UVM has installed eight different research watersheds with separate drains for measurement and data collection to see where green roof installation practices can improve and what plants thrive in a green roof system.

Amanda Czepiel, J.D., is a Legal Editor for BLR’s environmental law publications. Ms. Czepiel has over 6 years of experience as an attorney and writer in the field of environmental compliance resources and has published numerous articles on a variety of environmental law topics, including wastewater and NPDES permitting, brownfields and contaminated sites remediation, oil spill prevention, wetlands, and corporate sustainability. Before starting her career in publishing, Ms. Czepiel worked in hospitality consulting and for various non-profit organizations and government agencies in the environmental field. Ms. Czepiel received her law degree from the University of Connecticut School of Law.