CRWA in the News

Chestnut Hill Square: A Watershed View

By Kate Bowditch

Newton TAB, Wednesday, April 5, 2006

Mention the proposed development of Chestnut Hill Square, on Route 9 near the Newton/Brookline border, and you are likely to hear groans or worse. Already burdened with traffic during much of the day, area residents and commuters alike shudder to think of still more cars trying to make their way through the congested corridor.

But the site at 200 Boylston Street, home of the Omni Foods supermarket, an abandoned building shell and several acres of pavement, desperately needs to be redeveloped. Far more than just an eyesore and an economically underutilized parcel, the property is an environmental blight. Because it is almost entirely paved and impervious to rainwater, huge volumes of polluted stormwater run off the site and pour into the wetland system at the headwaters of the Saw Mill Brook every time it rains.

If it is done right, with up-to-date technologies and designs, the new development could begin to reverse decades of damage to an area once rich with water and wetland resources. Throughout the public review process, Charles River Watershed Association (CRWA) has encouraged the developers of the site to consider "green" site design, especially those commonly referred to as Low Impact Development (LID) techniques. Ideally, the new design will function less like a man-made hardscape and more like a natural landscape.

New England is just beginning to see building designs and site layouts that reduce damage to the environment. "Green" buildings like Genzyme´s new corporate headquarters in Cambridge incorporate energy and water conservation, recycled materials and natural light to promote a healthy workspace and reduce environmental impacts. LID programs like the pilot program in Wilmington to improve Silver Lake are proving that there are alternatives to traditional pavement-and-pipe systems for urban stormwater runoff.

The proposed development at Chestnut Hill Square could incorporate many of these designs. Each building could have a "green roof," a shallow layer of soil and plants that is built on top of a flat roof to absorb rainwater, reducing pollution and runoff volumes using the natural absorption and filtration of plants. The site could have far less paved, impervious cover, with more vegetation and trees, narrower roadways and permeable sidewalks and pedestrian areas. Runoff from roadway areas and surface parking lots could be directed to numerous, small "rain gardens" and vegetated swales. Stormwater could be collected after it has passed through these natural pre-treatment systems and directed to underground chambers, where some of it could be allowed to infiltrate, or seep into the ground, recharging the groundwater and feeding the Saw Mill Brook, which rises nearby.

All of these design elements provide multiple benefits. In addition to reducing downstream flooding and improving water quality, they reduce heating and cooling costs to the property, save energy, and improve the public realm. Across the country, developers of urban, environmentally impaired sites are realizing real economic returns on redevelopment that includes environmental restoration. In a place like the Chestnut Hill corridor, where redevelopment can impact traffic, air quality, noise and views, creating a site design that provides some real, measurable environmental benefits is a priority.

Only a few years ago, these suggestions were considered radical, and when watershed advocates tried to promote these techniques, developers and even regulators were skeptical that the benefits would be meaningful, or that the ideas were even possible. But today, the economic, environmental and quality-of-life benefits of green building designs and LID site designs are well recognized.

Across the United States, redevelopment of already developed parcels will soon surpass new development on open space as an economic sector. In mostly built-out, high land value areas like Newton, redevelopment is clearly the main kind of development. Certainly redevelopment brings real challenges to communities, like figuring out how to manage traffic and noise, and how to prevent our roadways from becoming urban "canyons." But redevelopment is also our best opportunity to improve our environment, to undo some of the damage we did when we built without understanding the long term impacts of paving land and piping water away.

Perhaps Chestnut Hill Square will begin to unpave the way.

Kate Bowditch, Senior Environmental Scientist and Project Manager at Charles River Watershed Association, is a hydrologist. She earned her MA in Geography/Water Resources Management from Boston University.

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