Charles River Watershed Association Green Infrastructure Demonstration Projects

The Charles River Watershed Association (CRWA), through its “Blue Cities Initiative,” develops demonstration projects that feature green infrastructure along streets and in other public and private spaces, with the goal of managing increases in precipitation caused by climate change. More frequent and intense rainfall events will increase the risks of flooding, sewer overflows, and water pollution in the Northeast. CRWA has implemented demonstration projects in the Boston metropolitan area to illustrate and assess the effectiveness of different green stormwater management techniques, including permeable pavements and roadside vegetation, and to encourage replication of these strategies in other areas.

CRWA’s demonstration projects focus on capturing rainfall and reducing runoff from roads and sidewalks. The projects employ two general strategies: the use of porous asphalt or pavers instead of traditional asphalt or concrete roads and sidewalks; and natural basins for water retention and ground or plant filtration such as rain gardens, stormwater tree pits, and infiltration trenches. These strategies collect water from areas adjacent to roads and sidewalks and retain, filter, absorb, or slow the flow of precipitation. Many of CRWA’s demonstration projects include changes to transportation infrastructure that will help reduce flooding and improve water quality and groundwater recharge.

Porous Alley Demonstration Project

The Porous Alley project in Boston, MA replaced a section of an alleyway with porous asphalt that filters stormwater naturally into the ground. The groundwater is therefore replenished where it is needed to support building foundations. This absorption also mitigates flooding, and the filtration effect of the asphalt decreases pollution in waterways fed by storm drains. The porous alley will be monitored for its effectiveness in increasing groundwater levels. Construction was completed in late summer of 2014 with funding from the Massachusetts Department of Environmental Protection, the City of Boston, and Boston Groundwater Trust and was designed by Vanasse Hangen Brustlin, Inc.

Everett Street Pilot Demonstration Project

Another demonstration project, called the Everett Street Pilot, replaced an asphalt parking lot in the Allston-Brighton area with green infrastructure to mitigate increased precipitation, warmer temperatures, and air quality problems expected to accompany climate change. New trees, two rain gardens, permeable pavers, and a stormwater tree pit were installed along Everett Street. A rain garden trench was also installed to treat runoff from a nearby school parking lot. Benefits of the project include more shade and community green space, reduction in urban heat islands, improved air quality, and stormwater runoff filtration. The project is supported by the CRWA, the German International School of Boston, St. Anthony of Padua Church, and the Allston-Brighton Community Development Corporation.

Peabody Square Demonstration Project

The Peabody Square demonstration project in the Dorchester neighborhood of Boston is another effort to reduce the flow of stormwater runoff into a nearby, impaired waterway. The project involved redesigning a street intersection to address vehicle and pedestrian traffic while also incorporating new green infrastructure features. The design included a pedestrian plaza with porous pavers and a roadside rain garden and infiltration trench to treat runoff from the roadway. These measures will filter stormwater through the ground and plants and reduce water pollution. Partners of CRWA for this project include the City of Boston, MA and the Massachusetts Department of Environmental Protection.

The Blue Cities Initiative designs transportation improvements to mimic the way that natural landscapes handle precipitation. Its demonstration projects provide examples of strategies that can be implemented by the general public and city planners to reduce flood risks related to increasing precipitation and stormwater runoff.  By monitoring these projects, staff will also be able to evaluate the effectiveness of the various techniques that have been installed. As cities plan for increased precipitation levels and more frequent storm events, many of the green infrastructure strategies implemented by CRWA could prove extremely useful in reducing heat, water pollution, and flood risks. A road and sidewalk system that filters and absorbs water rather than funneling it quickly into waterways has environmental benefits and reduces multiple risks to the community.

 

This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on January 28, 2016.

 

Related Organizations:

  • Charles River Watershed Association
  • City of Boston, Massachusetts
  • Massachusetts Department of Environmental Protection

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  • Best practice
  • Case study

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