Green Infrastructure/Low Impact Development (GI/LID) features are stormwater management facilities that mimic nature. In the natural world, rainwater soaks, or infiltrates, into the soil. Unfortunately, in most cities and towns rainwater can no longer infiltrate into the ground because of buildings, pavement, sidewalks, and other surfaces that water cannot pass through. These hard surfaces, called "impervious" surfaces, generate stormwater runoff when rainwater falls and "runs off," rather than soaking into the ground. Conventional stormwater management, often referred to as "grey infrastructure," uses catch basins and storm drains to capture stormwater and pipe it, untreated, to nearby waterbodies.
Common GI/LID Practices
Rain gardens capture rainwater and allow it to filter through the soil and use vegetation to clean runoff before it enters the groundwater system. For more information on rain gardens see the Rain Garden Brochure.
Rain Garden Brochure
Tree pits and tree trenches allow stormwater to infiltrate into the soil around street trees and use trees to uptake the large volumes of stormwater running off surrounding areas.
Permeable Paving Surfaces
Permeable paving surfaces include paving materials such as porous asphalt and concrete and permeable pavers, which allow for urban uses, like driving and parking, while providing a path for stormwater to reach the soil underneath.
Stormwater chambers retain large volumes of stormwater after storm events and allow stormwater to infiltrate into the soil without impacting urban uses, like driving and parking.
Drywells capture smaller volumes of stormwater after storm events and allow stormwater to infiltrate into the soil without impacting urban uses, like driving and parking.
BWSC has undertaken several GI/LID projects to help demonstrate "green" alternatives to traditional "grey" stormwater management. Projects are located all over Boston, many in partnership with other city departments, including Boston Public Works Department, Boston Transportation Department, Boston Parks and Recreation Department, Boston Public Schools (BPS), and Boston Planning and Development Agency - all to foster a culture of collaboration and innovation among City Agencies.
BWSC's GI/LID projects include:
- Central Square in East Boston
- Audubon Circle
- GI at Five Boston Public Schools
- Rain Garden at South Street and Bussey Street
- Tree Trenches on Harrison Avenue
- Codman Square
Green Infrastructure at Boston Public Schools
BWSC installed GI/LID at the following five Boston Public Schools to reduce pollutant loading to the Charles and provide educational opportunities for City of Boston teachers and students.
- Washington Irving Middle School in Roslindale
- Rafael Hernandez K-8 School in Roxbury
- David A. Ellis Elementary School in Roxbury
- Jackson/Mann K-8 School and Horace Mann School for the Deaf and Hard of Hearing in Allston
- Edward M. Kennedy Academy for Health Careers in Roxbury
BWSC worked with a former BPS curriculum writer to author stormwater/GI curriculum for 5th and 7th grades, in accordance with the new MA Science and Technology/Engineering Standards, to accompany the five pilot projects.
Through the pilot projects and stormwater/GI curriculum, BWSC intends to build public awareness about green stormwater management. The master-planning process provides opportunities to reduce pollutants in the Charles River, improve BPS facility aesthetics, and illustrate the countless benefits of green stormwater management.
GI/LID that is both effective at pollutant removal and attractive was constructed at each school. During the design process, the project team also considered school needs. In schoolyards with large, paved areas and little shade, vegetated surfaces, and trees were incorporated. At schools where traffic patterns prevented students from playing outside, protected play spaces were created as a barrier between students and vehicle traffic.